Sub-cell FRET imaging for determination of signaling pathway of cell apoptosis during tumor therapy
Author(s):
Lei Liu D.D.S.;
Da Xing;
Wei R. Chen
Show Abstract
The current advances in fluorescence microscopy, coupled with the development of new fluorescent probes, make
fluorescence resonance energy transfer (FRET) a powerful technique for studying molecular interactions inside living
cells with improved spatial and temporal resolution, distance range, and sensitivity and a broader range of biological
applications. In recent years, a large number of studies have been conducted aiming to understand the process of
apoptosis during tumor therapy on a molecular basis. Here, we utilized a recombinant FRET Bid probe to determine
the kinetics of Bid cleavage during Cisplatin-induced apoptosis in ASTC-a-1 cells. Cells treated with Cisplatin (20 μM)
showed a cleavage of the Bid-FRET probe, occurring at about 4-5 h after onset of the Cisplatin exposure, and lasted
about 1.5 h. Our data clearly showed the kinetics of Bid cleavage during Cisplatin-induced apoptosis. We also used
FRET technique to measure the dynamics of caspase-3 activation during apoptosis induced by high fluence low-power
laser irradiation (LPLI). The data showed that we can detect caspase-3 activation sensitively and effectively, by using
the FRET probe SCAT3.
Cellular rehabilitation of photobiomodulation
Author(s):
Timon Cheng-Yi Liu;
Jian-Qin Yuan;
Yan-Fang Wang;
Xiao-Yang Xu;
Song-Hao Liu
Show Abstract
Homeostasis is a term that refers to constancy in a system. A cell in homeostasis normally functions. There are two kinds
of processes in the internal environment and external environment of a cell, the pathogenic processes (PP) which disrupts
the old homeostasis (OH), and the sanogenetic processes (SP) which restores OH or establishes a new homeostasis (NH).
Photobiomodualtion (PBM), the cell-specific effects of low intensity monochromatic light or low intensity laser
irradiation (LIL) on biological systems, is a kind of modulation on PP or SP so that there is no PBM on a cell in
homeostasis. There are two kinds of pathways mediating PBM, the membrane endogenetic chromophores mediating
pathways which often act through reactive oxygen species, and membrane proteins mediating pathways which often
enhance cellular SP so that it might be called cellular rehabilitation. The cellular rehabilitation of PBM will be discussed
in this paper. It is concluded that PBM might modulate the disruption of cellular homeostasis induced by pathogenic
factors such as toxin until OH has been restored or NH has been established, but can not change homeostatic processes
from one to another one.
1310nm high-power, broad-band superluminenscent laser diode for OCT application
Author(s):
Lisa Tongning Li;
Xiangjun Zhao;
Jingyi Wang;
Jinyan Jin;
Zhenghua Wu;
Weiming Zhu;
Wenchao Xu
Show Abstract
Super-luminescent laser diodes (SLD) in 800 to 1300 nm wavelength windows have been widely used in optical
coherence tomography (OCT) systems. The imaging resolution of OCT systems is proportional to the bandwidth of the
SLD light source. Here we present a new design to achieve broad bandwidth (>100nm at 1310nm) in one chip by using
two types of quantum wells.
The bandwidth of an SLD with a single active region is determined by the material bandwidth, confinement factor, and
the length of the active region. Neglecting spatial hole burning (SHB), the spectral density of amplified spontaneous
emission (ASE) can be the function of cavity length and spectral density of spontaneous emission and net gain. The main
factor that limits the ASE bandwidth is the net gain. The bandwidth of net gain has to be larger than 200 nm to obtain a
100 nm wide ASE spectrum if the ASE power is larger than several mW.
SLDs usually work at very high pump current (>400mA) to achieve high output power. From simulations, we found the
level of electron injection mainly determines the material gain. At the high injection level, large bandgap quantum wells
can get high gain and dominate the spectrum if the improper design is used. So in our design, we put the small bandgap
quantum wells at the N side to make the electron distribution in favor of long-wavelength material. Thus, and will be
balanced at high current injection level (>550mA). Figure 7 shows the measured spectrum of such structure. The
achieved spectral width is larger than 100nm and out put power is larger than 5 mW.
Distinguish activations on sensorimotor cortex using high-resolution diffuse optical tomography
Author(s):
Qing Zhao;
Lijun Ji;
Feng Shi;
Tianzi Jiang
Show Abstract
Diffuse optical tomography (DOT) is an appropriate tool for non-invasive exploration of human brain activation. The
activation of sensorimotor cortex has been studied by several researchers since the first images of human brain were
generated in 1995. However, high-quality images of sensorimotor cortex can not be obtained until the emerging of
high-resolution DOT which uses a multi-centered geometry for arranging optical fibers. In this study, we did two
experiments using our CW5 instrument (TechEn, USA). In the first experiment, the subject was asked to move his four
fingers of right hand for 30 seconds, followed by 30 seconds of rest. Data collection lasted 420 seconds. In the second
experiment, the subject was asked to tap his thumb against the other four fingers. Two conclusions can be reached from
the experiments. Firstly, larger activated regions can be found on motor cortex in experiment 2 than in experiment 1.
This indicates that high-resolution DOT can detect larger activated brain region when moving five fingers comparing to
moving four fingers. Secondly, few activated regions can be found on sensory cortex in experiment 1, but it can be
clearly found on sensory cortex in experiment 2. Up to our knowledge, it is the first time DOT has detected activated
region on sensory cortex during motorial task.
Wave-front division fourier domain optical coherence tomography
Author(s):
Jiechen Yin;
Qin Miao;
Ping Xue
Show Abstract
A power-conserving wave-front division Fourier domain optical coherence tomography (WD FDOCT) has been
successfully demonstrated. Unlike conventional Michelson-based FDOCT system, splitting ratio of WD FDOCT can be
arbitrarily adjusted to enhance signal-to-noise ratio (SNR). Both theoretical and experimental SNR of this system are
evaluated. WD FDOCT imaging of the anterior eye of a rat is also demonstrated.
Influence of source power on spatial-resolved diffuse reflectance close to the source
Author(s):
Lijun Wang;
Ying Liu;
Yunfeng Guo;
Huijuan Tian
Show Abstract
Influence of source power on spatial-resolved diffuse reflectance in the region close to the source is studied
experimentally. The fiber detector method is performed and the diffuse reflectances from 0.3mm-2.675mm
source-detector separations are measured. The source is a 650nm diode laser and its maximum power is 10mw. The
experimental result shows that the influence of source power on the diffuse reflectance from a tissue phantom at short
source-detector separations is considerable. Also, this influence is found different from the effect of scattering
coefficient (μs) and absorption coefficient (μa) on the diffuse reflectance. These results are important to measure the
optical parameters of the tissue from the diffuse reflectance.
Adaptive optics optical coherence tomography
Author(s):
Guohua Shi;
Zhihua Ding;
Yun Dai;
Xunjun Rao;
Yudong Zhang
Show Abstract
When optical coherence tomography (OCT) is used to image human retina, its lateral resolution is deteriorated by the
aberrations of the human eye. To get over this disadvantage, a high-resolution imaging system combining OCT with
adaptive optics (AO) is being developed. The AO system consists of a 61-element deformable mirror and a 16×16 array
Shack-Hartmann wave front sensor. In this paper, the configuration of the AO/OCT system is described, and the
simulation results and the static aberration analysis of AO/OCT systems are presented.
Research on animal laser varicose treatment in CIOMP, CAS
Author(s):
Laiming Zhang;
Dianjun Li;
Qipeng Lu;
Guilong Yang;
Jin Guo
Show Abstract
The work on laser varicose treatment carried out in CIOMP, CAS cooperating with The First Clinical Hospital, Jilin
University is summarized. Dozens of animal experiments adopting dog and rabbit samples are made in a long time of
several years. Different lasers are used, including long pulse frequency-doubled Nd:YAG(532nm) and semiconductor
laser(808nm). Dozens of animal experiments show that laser has good efficacy to occlude the vein vessels. It has precise
adjustability and relatively short treatment time only needing outpatient office setting with high cost and effect rate; It
provides minimal invasion, often under local anesthesia and intravenous sedation thereby eliminating the need for
general anesthesia, greatly shortens postoperative recovery term, and it is highly safe with no side effects and no serious
complications.
Polarization gated imaging in turbid media: a study with Monte Carlo simulation
Author(s):
Wei Li;
Hanrong Shao;
Honghui He;
Yonghong He;
Hui Ma
Show Abstract
Polarized light has been increasingly used in biomedical imaging to study the optical properties of biological tissues or
enhance the imaging contrast by eliminating the scattered light. In this report, we combine polarization gating and
Fourier gating to suppress interference by the diffusive photons and improve the quality of projection images. A Monte
Carlo simulation is utilized to study the propagation of different polarized light through turbid media. Polarization of a
photon is represented by a Stokes vector and the scattering matrix is calculated from Mie theory. By tracing the trajectory
and the polarization of the photons, spatial distribution and polarization of photons transmitted through a spatial filter
aperture are simulated. It is shown that polarization gating and Fourier gating can effectively reject the multiple scattered
photons and improve the contrasts of the images. Differences between linearly and circularly polarized lights for
scatterers of different size are compared. However, for large particles, effects of both gating techniques are limited.
Contrasts of the polarization difference projection images with linearly and circularly polarized lights
Author(s):
Nana Wang;
Hanrong Shao;
Yonghong He;
Hui Ma
Show Abstract
Polarization gating has been an attractive technique for optical imaging in turbid media. In this study, we investigate the
polarization difference projection image (PDPI) in turbid media with linearly and circularly polarized lights. An iris is
placed at the focal spot of the imaging optics to examine the influence of spatial filtering on imaging contrast.
Polystyrene microsphere suspensions in Rayleigh and Mie domains are used as the phantoms. Scattering coefficient μs
and anisotropy factor g are varied independently to obtain the quantitative relation between the PDPI contrasts and the
optical properties of the phantom. We also compare the PDPI contrast with the contrast of degree of polarization (DOP).
Primary results show that the PDPI contrast is better than DOP image contrast either in Rayleigh or Mie scattering
domain. In the Mie scattering domain, linear and circular PDPI contrasts are compared for different scattering
coefficients. We also discussed how Fourier spatial gating improves the image contrast. The results are compared with
Monte Carlo simulation.
Resonance-based rapid scanning fiber cantilever for forward-imaging optical coherence tomography
Author(s):
Gang Huang;
Zhihua Ding;
Ling Wu;
Shengman Wang
Show Abstract
We develop a fast scanning probe for forward-imaging optical coherence tomography (OCT). The
probe is based on the resonant oscillation of a fiber cantilever which has two distinguished resonant
frequencies intrinsic to its geometry. When actuated by piezoelectric bimorph with signals of mixed
frequencies, various two-dimensional traversal scanning patterns are generated. Experiments on
different probe parameters relating to the qualities of the final images- such as the density of the
scanning coverage, frame rate are carried out. For correct image reconstruction, a micro
two-dimensional position-sensitive detector (PSD) is also introduced to record the scanning pattern in
real-time. Preliminary results of OCT imaging with this developed probe are presented.
Double grating based rapid scanning optical delay line for dispersion compensation in optical coherence tomography
Author(s):
Dong Li;
Zhihua Ding
Show Abstract
A method for dispersion compensation in optical coherence tomography (OCT) by a double-grating based rapid scanning
optical delay line (RSOD) is put forward. The added grating introducing an independent variable of the distance
between gratings, along with the adjustable distance between grating and Fourier transform lens in a conventional RSOD
can be used to compensate the group velocity dispersion (GVD) and the third order dispersion (TOD) of OCT system
simultaneously. Theoretical development of the dispersion characteristics as well as the dispersion management
scheme is given. Example of dispersion compensation in a typical OCT system is provided.
Noninvasive measurement of glucose concentration using OCT based on the extended Huygens-Fresnel principle
Author(s):
Xuefang Li;
Youwu He;
Zhifang Li;
Hui Li
Show Abstract
We have developed a noninvasive method to monitor the glucose concentration in tissue phantom used the OCT model
which based on the extended Huygens-Fresnel (EHF) principle. The changes of the optical properties such as the
scattering coefficient μs,
the anisotropy factor g and the effective scattering coefficient μs
with the increase of the
glucose concentration in 10% Intralipid solution were obtained. The results showed that the scattering coefficient
μs
decreased when the glucose concentration increased in the solution, which is accorded with the conclusions by others.
Contrarily, the factor
g increased when the glucose concentration grown up. As a result, the coefficient μs is fall with
the increased of the glucose concentration. Comparing with those previously reported in which only got the relative
value of scattering coefficient
μs,
the most important advantage of our model is that we got the practical value of μs, g and μs.
All of these reveal that the OCT EHF model is a
promising method which is adapted to detect the glucose
concentration in solution, and it will be applied in medical fields someday.
Determining tissue optical properties by optical coherence tomography
Author(s):
Kai Wang;
Zhihua Ding;
Ling Wang
Show Abstract
Accurate measurement of tissue optical properties becomes more and more important in biomedical applications such as
diagnostic imaging for tissue pathology. Taking account of multiple scattering effects in OCT model, an algorithm is
developed to extract depth-resolved tissue optical properties including scattering coefficient and anisotropy factor. By
adding absorption coefficient as the third fitting parameter in the algorithm, it is possible to reduce fitting errors
introduced by sample absorption. With an adapted algorithm based on the extended model, absorption coefficient can
also be extracted. The validity of those algorithms is verified by sample model of solution of polyethylene sphere (PS).
Numerical analysis on RSOD-based phase modulation in OCT
Author(s):
Ling Wang;
Zhihua Ding;
Kai Wang
Show Abstract
Optical coherence tomography (OCT) is an emerging technology for high-resolution bio-medical imaging. The rapid
scanning optical delay line (RSOD) has developed basically for depth scanning and dispersion compensation. If the
pivot center of the galvamirror in RSOD is offset, phase modulation can be realized, providing a high carrier frequency
required for heterodyne detection. However, the size of galvamirror should be increased, leading to lower response for
its oscillation and hence a low scanning rate. In this paper we propose to apply a sinusoidal waveform (resonant scan)
instead of a triangle waveform (linear scan) to the galvamirror. Numerical analysis on phase modulation by RSOD and
successive envelop demodulation under different driving waveform is conducted. We demonstrate that it is possible to
improve OCT frame rate by resonant scan without compromising the signal-to-noise performance if complete and
accurate envelope demodulation and appropriate signal processing are adopted.
Effect of coherence length and numerical aperture on the formation of OCT signals from model biotissues
Author(s):
Mikhail Yu. Kirillin;
Alexander V. Priezzhev;
Risto Myllyla
Show Abstract
Maximal depth of non-distorted imaging is an important characteristic, which shows the efficiency of an application of a
certain OCT setup for imaging the given object. This characteristic depends on the setup parameters and the properties of
the studied object. The definition of the maximal depth of non-distorted imaging based on the classifications of photons
contributing to the signal in dependence on the relations of their optical travel pathlength in the object and maximal
reached depth was used in this work. We studied the effect of the coherence length and the detection angle on the
formation of OCT signals and images from model biotissues as well as on the maximal depth of non-distorted imaging.
The signals and images were obtained by implementing the Monte Carlo technique developed in our earlier works. The
following single- and multilayer biotissue phantoms were considered as the studied objects: erythrocyte suspension at
physiological hematocrit (35%), 2% intralipid solution reported to have optical properties close to those of skin in optical
and NIR range, and multilayer human skin phantoms. For the simulations, the parameters of the OCT setup were chosen
in accordance with real ones. The wavelengths of the light sources were chosen 820 and 910 nm. The conducted
simulations show that a decrease in the detection angle and an increase in the coherence length increase the maximal
probing depth in the studied objects due to smaller role of multiple scattering photons in the formation of the OCT
signals. The obtained value of maximal depth of non-distorted imaging varies in the range from 50 to 600 μm depending
on the values of the setup parameters.
Realization of 2D scanning pattern of a fiber cantilever by nonlinear coupling
Author(s):
Ling Wu;
Zhihua Ding;
Gang Huang
Show Abstract
Optical coherence tomography (OCT) is a recently developed high resolution biomedical imaging method. Fast scanning
speed and miniature probe is benefit for clinical applications of OCT. In this paper we present a method to realize fast
lateral scanning with two-dimensional (2D) resonant scanning pattern. By driving a fiber cantilever with a bimorph
actuator near its resonance, the planar motion of the fiber cantilever may develop to an elliptical motion due to nonlinear
coupling with longitudinal inertia. This effect can be exploited to form 2D scanning pattern. Basic principle relevant to
realization of 2D scanning pattern of the fiber cantilever scanner by 1D actuator, as well as confirming experimental
results are presented. Future work and system configuration on implementing this fiber cantilever scanner in the sample
arm of a fiber-based OCT system is proposed.
Numerical simulation of the micro-explosion during hard tissue ablation with infrared laser
Author(s):
Yucheng Yao;
Zhengjia Li;
Chuyun Huang;
Hongxing Xia
Show Abstract
A numerical simulation of the micro-explosion process during hard tissue ablation with infrared laser has been developed.
This simulation investigates the explosion dynamics evolution of the water film in the Er:YAG and CO2 laser irradiation
and calculates the pressure and intensity of impulse on the hard tissue surface. The calculation results indicate that the
micro-explosion has its special duration for different parameters. The pressure on the target surface caused by the explosion
increases rapidly with the laser intensity increase and the maximal pressure value appeared for an adaptive water film
thickness.
Ventrolateral prefrontal activation during a N-back task assessed with multichannel functional near-infrared spectroscopy
Author(s):
Yuan Zhou;
Ye Zhu;
Tianzi Jiang
Show Abstract
Functional near-infrared spectroscopy (fNIRS) has been used to investigate the changes in the concentration of
oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin in brain issue during several cognitive tasks. In the present
study, by means of multichannel dual wavelength light-emitting diode continuous-wave (CW) NIRS, we investigated the
blood oxygenation changes of prefrontal cortex in 18 healthy subjects while performing a verbal n-back task (0-back and
2-back), which has been rarely investigated by fNIRS. Compared to the 0-back task (control task), we found a significant
increase of O2Hb and total amount of hemoglobin (THb) in left and right ventrolateral prefrontal cortex (VLPFC) during
the execution of the 2-back task compared to the 0-back task (p<0.05, FDR corrected). This result is consistent with the
previous functional neuroimaging studies that have found the VLPFC activation related to verbal working memory.
However, we found no significant hemisphere dominance. In addition, the effects of gender and its interaction with task
performance on O2Hb concentration change were suggested in the present study. Our findings not only confirm that
multichannel fNIRS is suitable to detect spatially specific activation during the performance of cognitive tasks; but also
suggest that it should be cautious of gender-dependent difference in cerebral activation when interpreting the fNIRS data
during cognitive tasks.
Registration of intraoperative optical image sequence
Author(s):
Ming Li;
Yugang Jiang;
Yadong Liu;
Lingyun Zhang;
Xiaogang Chen;
Dewen Hu
Show Abstract
In neurosurgery, cortical warping is one of the significant sources of noises during optical imaging after the skull and the
dura have been removed. The optical image sequence must be registered for further data analysis. The registration
algorithms in widely used medical image tools, e.g. Automated Image Registration (AIR), Statistical Parametric
Mapping (SPM), usually express the cortical warping as polynomials or terms of cosine basis. However, these nonlinear
models do not faithfully fit the elastic warping of the cortexes, and thus can not achieve a satisfactory result. Based on
the elastic model, i.e., the approximating thin-plate splines (aTPS), we propose herein an improved aTPS (iaTPS)
algorithm to deal with the elasticity of the cortical warping. In the cost function of the original aTPS algorithm,
landmarks with different localization uncertainties should be given different weights, however, due to the absence of a
convincing method to specify these weights, a same weight value was manually set for all landmarks in practice. In our
iaTPS algorithm, landmarks are categorized into several classes (usually 3~5) by their localization uncertainties, and the
weights for each class are decided by an optimization process. The comparison experiment on the intraoperative optical
data of human brain has shown that the new algorithm can offer better registration accuracy than the aTPS algorithm.
Contourlet based mammographic image enhancement
Author(s):
Zhibo Lu;
Tianzi Jiang;
Guoen Hu;
Xin Wang
Show Abstract
In original mammographic images obtained by X-ray radiography, only a small part of detected information is displayed
to the human observer. A method aimed at minimizing image noise while optimizing contrast of mammographic image
features is presented in this paper, for more accurate detection of microcalcification clusters. The method is based on the
contourlet transform, which is a multiresolution, local and directional image representation. The difference from wavelet
and other multiscale expansion lies in that the contourlet transform is constructed by using non-separable filter banks in
discrete-domain, thus it can effectively capture important features of images. The enhancement procedure consists of two
steps: noise filtering by the Stein's thresholding and denoised contourlet coefficients modification via a nonlinear
mapping function. The experimental results have shown an improved visualization of significant mammographic features
by the proposed method. A comparison with other enhancement algorithms is also discussed by employing a measure
named target to background contrast ratio using variance.
Light scattering by biological spheroidal particles in geometric optics approximation
Author(s):
Andrei E. Lugovtsov;
Alexander V. Priezzhev;
Sergei Yu. Nikitin
Show Abstract
The main goal of this work is the fast analysis of light scattered by a large optically soft spheroidal particle (size
parameter ka > 20). In particular, these particles mimic single cells (e.g., red blood cells (RBC)) and their
aggregates. Methodology of calculation of light scattering by arbitrarily oriented optically soft spheroidal particles
in geometric optics approximation is presented. We show that the geometric optics approximation permits to
quickly calculate the angular distributions of the intensities and phases of light scattered from optically soft
particles, such as erythrocytes.
Response of diffuse reflectance light of two-layered tissue to optical properties of inner layer
Author(s):
Dongqing Peng;
Hui Li;
Shusen Xie
Show Abstract
Although measurement of diffuse reflectance light can be used to determine the optical properties of tissue noninvasively,
great effort should be firstly devoted to the development of the relation between the reflectance and optical properties of
tissue in our opinion. In this paper, light diffuse reflectance by a tissue optical model with two-layered structure is
discussed by use of Monte Carlo method. The distribution of diffuse reflectance vs. emitting angle at different optical
properties of inner layer is calculated. In addition, the influence of the changing absorption coefficient, scattering
coefficient of the inner layer on the light diffuse reflectance from the surface is investigated and analyzed. The
simulation results show that the diffuse reflectance light is sensitive greatly to micro-change of optical properties
(absorption coefficient and scattering coefficient) of the inner layer which has small value of optical properties. We
believe that the results will be useful for the development of determination the optical parameters of bio-tissue in vivo.
Sensitivities of reflectance to scattering variations in a diffusive medium
Author(s):
Xiaojuan Zhang;
Ying Liu
Show Abstract
The sensitivity expression of spatial-resolved diffuse reflectance to scattering parameter is deduced in the P3
approximation model, and the influence of scattering parameter on the reflectance is analyzed using this expression. The
results show that the sensitivity is distinct with that of the diffusion approximation in the region of about one transport
mean free path, and optimum source-detector distance where the sensitivity to scattering parameter equals zero differs
from the diffusion approximation's too.This optimum source-detector distance is found shortened when a medium has
bigger scattering coefficient or bigger absorption coefficient. The research is very valuable for in vivo measurement
based on the spatial-resolved diffuse reflectance.
Effects of isoflurane on measurement of fluorescence spectra and CLSM imaging in Acetabularia acetabulum
Author(s):
WenLi Chen D.D.S.;
Zhou Quan;
Da Xing
Show Abstract
The volatile halogenated methyl ethyl ether is used as anesthetic to inhibit actin-based dynamics directly or indirectly in
animal cells. In plant cells, most intracellular movements are related with actin pathways too. We utilized isoflurane to
study the dynamic choloroplast organization in unicellular baby and adult alga Acetabularia acetabulum. Fluorescence
spectra were measured and choloroplast movements were recorded by confocal laser scanning microscope (CLSM)
imaging in in Acetabularia acetabulum. Isoflurane was effective in the unicellular baby and adult organisms and showed
time- dependent actin-inhibition patterns. Acetabularia acetabulum cells were treated for different times with
isoflurane saturated solutions in artificial seawater (it was defined to be 100% isoflurane). The intensity of fluorescence
at 680nm and 730nm were progressively decreased at 100% isoflurane. It was remarkable difference between
fluorescence spectra of baby and adult Acetabularia were inhibited by isoflurance, adult Acetabularia cells showed more
sensitive. Whereas the choloroplast in Acetabularia acetabulum was commendably imaged by CLSM at 20 and 40 zoom.
Expanded research of spectroscopic optical tomographic functional imaging system
Author(s):
Yuheng Chen;
Zhihua Ding;
Jie Meng
Show Abstract
Spectroscopic optical coherence tomography (OCT), a functional extension of conventional structural OCT is developed
based on previous fiber-based OCT system. Spectral information is obtained by carrying out Fourier transformation of
the detected OCT signal without recurring to hardware. The developed system is applied to film reflectivity
measurement and spectroscopic imaging of a finger from a human volunteer. The feasibility for spectroscopic
extension of the developed system is confirmed by comparison curves of film reflectivity measured by the developed
system with that obtained from a commercial spectrometer.
Determination of optical properties in tissue: modeling and simulation
Author(s):
Zheng Ma;
Dongli Qin;
Feng Gao
Show Abstract
In this paper, a Monte Carlo (MC) based model of diffuse reflectance is introduced to retrieval the light absorption and scattering
coefficients of multi-layered tissue. The absorption and transport scattering coefficients of biological tissues determine the radial
dependence of the diffuse reflectance that is due to a point source. The MC model of diffuse reflectance consists of a forward part and an
inverse one. The forward refers to a multi-layered MC simulation at a certain source detector separation, which results a time-resolved
profile. The inverse one is a fitting procedure based on Levenberg-Marquardt algorithm using forward model in iteration, and the
normalized intensity in each time bin is fitted. Tests with independent MC simulations show the errors in the deduced absorption and
reduced scattering coefficients. Although a high amount of computation time is needed, compared with investigation methods using
diffuse approximation to the transport equation, this model is valid for a wider range of optical properties and is easily adaptable to
exiting probe geometries.
Determination of optical properties in turbid medium based on time-resolved determination
Author(s):
Dongli Qin;
Zheng Ma;
Feng Gao;
Huijuan Zhao
Show Abstract
In this article, we briefly described a time-correlated single photon counting (TCSPC) system specifically designed
for extracting the optical properties in turbid medium. This system was evaluated by use of two sets of liquid
tissue-simulating phantoms containing different concentrations of Intralipid-10% as scatters and India ink as
absorbers. With the distribution of times of flight (DTOF) of photons measured by the TCSPC system, some
featured parameters, such as the mean time of flight and the variance of DTOF were calculated. Based on these
parameters, we developed a simple and fast method to obtain the absorption coefficient μa and reduced scattering
coefficient μs
of the turbid medium. Furthermore, the accuracy of the method was validated using the Monte Carlo
simulations. It was found that the optical properties could be extracted with this method, which was much faster
than the conventional curve-fitting procedure. Our method could be useful in on-line monitoring of optical
properties of biological tissue.
Full-field optical coherence tomography by achromatic phase shifter with a rotating half-wave plate
Author(s):
Yaliang Yang;
Zhihua Ding
Show Abstract
In optical coherence tomography (OCT), broad-bandwidth optical sources are required to achieve high axial resolution.
Introducing a variable phase shift achromatically between the probe and reference beams is required for phase-shifting
algorithms implemented to extract the coherence signal. We propose a full-field OCT using an achromatic phase shifter
based on wave plates. The phase shifter that is almost independent of the wavelength over a range of 240 nm, can
provide a phase shift of eight times the rotating angle of the half-wave plate. The system is based on a Michelson
interferometer, illuminated by a white light source, and has several advantages compared with previous implementation
of full-field OCT based an achromatic phase shifter. Numerical simulation on phase shift error and amplitude ratio
between orthogonal polarization components at nominal phase shifts required for two typical phase-stepping algorithms
is conducted. Approach for extracting OCT signal by the revised Carre algorithm is presented.
The analysis of laser influence on partial bonds of DNA and its application onto breeding
Author(s):
Can-Bang Zhang;
Jia-Jin Tian;
Zhi-Fu Dai;
Bo Gao;
Ling-Yun Zhou
Show Abstract
With the model of harmonic oscillator in quantum mechanics, we derive the interaction equations between laser and
molecule bonds. We conclude that Laser- irradiated process can lower molecule energy level, improve the biological
activity, shorten the period of mature according to the investigation on the seed of "Sangjiao sticky rice". The technique
of Raman spectroscopy also is used to analysis the sample groups and contrast groups.
Analysis on interaction effect of terahertz radiation with living biology system
Author(s):
Zhifu Dai;
Canbang Zhang;
Shengyu Wang;
Lingyun Zhou
Show Abstract
In the first place, the coherent collective vibration models of the living biological molecule system (e.g. DNA and
protion) are analyzed in this paper. Then we have analyzed yet order-disordering variance due to resonance effect and the
nonlinear behavior of terahertz radialion(THR)-biological system interaction. The analytic results show that the
interaction between the living biological system and THR can produce resonance excitation effect, and so the system can
be produced under further action of the laser. In addition, we have analyzed the nonlinear properties of the THR
bio-molecule interaction and explained the mutagenesis effects of THR. The theoretic analysis is consistent with the
results of THR biological test.
Ultra-weak photon emission and its mechanism during tomato ripening
Author(s):
Shanshan Tian;
Hao Qi;
Shuli Li;
Jintao Bai
Show Abstract
Experiments were carried out using the tomato (Lycopersicon esculentum) stored at 28°C and 4°C , at the same time, the
spontaneous ultra-weak photon emission (UPE), delayed luminescence (DL), ethylene releasing, respiratory intensity,
chroma main wavelength and chlorophyll content were detected. It was found that: The curve of the spontaneous UPE is
just consists with respiratory intensity at 28°C and relate to chlorophyll content variation. The experiment data were
given guide line to noninvasive test maturity, DL data were dealt with curve fitting and compared with coherent theory.
Different hemodynamic response of prefontal area for men and women to mental arithmetic: a near-infrared spectroscopy study
Author(s):
Hongyu Yang;
Zhenyu Zhou;
Yun Liu;
Zongcai Ruan;
Hui Gong;
Qingming Luo;
Zuhong Lu
Show Abstract
A 16-channel near-infrared spectroscopy (NIRS) was used to measure concentration changes of oxygenated and
deoxygenated hemoglobin (oxy-HB and deoxy-HB) in prefrontal area while the subjects were performing mental works.
Thirty healthy college participants were administered two mental arithmetic tasks while the changes of concentration on
oxy-HB and deoxy-HB were measured. Oxy-HB increased during the mental works, and the increases of oxy-HB were
greater in male subjects than in female subjects during the difficult task. These results suggest that NIRS is sensitive to
evaluate the oxy-HB activity of prefrontal cortex during mental works.
Nondestructive determination of pear internal quality indices by near-infrared spectrometry
Author(s):
Yande Liu;
Xingmiao Chen;
Aiguo Ouyang;
Yibin Ying
Show Abstract
The objectives of the study were to establish relationships between the nondestructive near-infrared (NIR) spectral
measurements and the major internal quality indices of pear ('Fengshui', Jiangxi) fruit, and to evaluate the use of NIR
spectrometry in measuring the internal quality indices of pear fruit. Intact pear fruit were measured by reflectance NIR in
350-1800 nm range. In this study, Calibration models relating NIR spectra to soluble solids content (SSC), and firmness
were developed based on multi-linear regression (MLR), Principal component analysis (PCA) and partial least square
(PLS) regression with respect to the logarithms of the reflectance reciprocal log (1/R), its first derivative D1log (1/R)and
second derivative D2log (1/R). The best combination, based on the prediction results, was MLR models with respect to
D1log (1/R) at equatorial position of pear fruit. Prediction with MLR models resulted correlation coefficients (Rp) of
0.9151 and 0.8125, and root mean standard error of prediction (RMSEP) of 0.6834 and 1.3778 for SSC and firmness,
respectively. The preliminary results of the built models indicated that NIR spectroscopy could provide an accurate,
reliable and nondestructive method for assessing the internal quality indices of pear fruit.
Preliminary research of measurement methods for optical property parameters in fruit tissue
Author(s):
Jianping Wen;
Xingmiao Chen;
Yande Liu
Show Abstract
The research for optical transmission in biomedicine has been studied for many years at domestic and abroad, but the
applicative research for nondestructive measuring in fruit internal qualities has not been found nowadays. Therefore, the
transmission mechanism and the research methods of optical transmission in biomedicine can be applied in fruit internal
qualities analysis. It will give a chance to improve measuring precision in fruit internal qualities. In this paper, the optical
transmission mechanism in fruit tissue, the optical property parameters of fruit tissue, the models of optical transmission
in fruit tissue and the measurement methods of optical parameters in fruit tissue have been researched respectively.
Meanwhile, an important measurement method, namely integrating sphere technology, is presented. It will provide the
theoretical foundation for the research for nondestructive measuring in fruit internal qualities.
Study of a new parameter used in objective measurement of skin erythema
Author(s):
Keke Shang;
Ying Liu;
Yixing Lu;
Yu Guo;
Lijun Wang;
Xiaoqi Chang
Show Abstract
The objective measurement of skin erythema is of much importance in clinical dermatological diagnosis and new
dermatological drug tests. The measurements that used currently are facing a main problem that all the
measurements are deeply influenced by the melanin in the epidermis and the incident intensity. Basing on the skin
optical model, a new parameter is introduced in order to describe the change of erythema. The new parameter is
defined by the difference of the logarithm of the diffuse reflected light intensity between normal skin and erythema
skin. The theoretical analysis shows that this new parameter can reflect directly the deviation of the concentration of
haemoglobin from the normal range under the assumption of keeping the concentration of melanin constant and the
illuminating light uniform. In addition, the experimental study also shows that this method is hardly influenced by
the illuminating light intensity, and can be effectively applied in the clinical diagnosis.
Microscopic fluorescence spectral analysis of basal cell carcinomas
Author(s):
Qingli He;
Harvey Lui M.D.;
David Zloty;
Bryce Cowan;
Larry Warshawski;
David I. McLean M.D.;
Haishan Zeng
Show Abstract
Background and Objectives. Laser-induced autofluorescence (LIAF) is a promising tool for cancer diagnosis. This
method is based on the differences in autofluorescence spectra between normal and cancerous tissues, but the underlined
mechanisms are not well understood. The objective of this research is to study the microscopic origins and intrinsic
fluorescence properties of basal cell carcinoma (BCC) for better understanding of the mechanism of in vivo fluorescence
detection and margin delineation of BCCs on skin patients. A home-made micro- spectrophotometer (MSP) system was
used to image the fluorophore distribution and to measure the fluorescence spectra of various microscopic structures and
regions on frozen tissue sections. Materials and Methods. BCC tissue samples were obtained from 14 patients
undergoing surgical resections. After surgical removal, each tissue sample was immediately embedded in OCT medium
and snap-frozen in liquid nitrogen. The frozen tissue block was then cut into 16-&mgr;m thickness sections using a cryostat
microtome and placed on microscopic glass slides. The sections for fluorescence study were kept unstained and unfixed,
and then analyzed by the MSP system. The adjacent tissue sections were H&E stained for histopathological examination
and also served to help identify various microstructures on the adjacent unstained sections. The MSP system has all the
functions of a conventional microscope, plus the ability of performing spectral analysis on selected micro-areas of a
microscopic sample. For tissue fluorescence analysis, 442nm He-Cd laser light is used to illuminate and excite the
unstained tissue sections. A 473-nm long pass filter was inserted behind the microscope objective to block the
transmitted laser light while passing longer wavelength fluorescence signal. The fluorescence image of the sample can be
viewed through the eyepieces and also recorded by a CCD camera. An optical fiber is mounted onto the image plane of
the photograph port of the microscope to collect light from a specific micro area of the sample. The collected light is
transmitted via the fiber to a disperserve type CCD spectrometer for spectral analysis. Results. The measurement results
showed significant spectral differences between normal and cancerous tissues. For normal tissue regions, the spectral
results agreed with our previous findings on autofluorescence of normal skin sections. For the cancerous regions, the
epidermis showed very weak fluorescence signal, while the stratum corneum exhibited fluorescence emissions peaking at
about 510 nm. In the dermis, the basal cell island and a band of surrounding areas showed very weak fluorescence signal,
while distal dermis above and below the basal cell island showed greater fluorescence signal but with different spectral
shapes. The very weak autofluorescence from the basal cell island and its surrounding area may be attributed to their
degenerative properties that limited the production of collagens. Conclusions. The obtained microscopic results very
well explain the in vivo fluorescence properties of BCC lesions in that they have decreased fluorescence intensity
compared to the surrounding normal skin. The intrinsic spectra of various microstructures and the microscopic
fluorescence images (corresponding fluorophore distribution in tissue) obtained in this study will be used for further
theoretical modeling of in vivo fluorescence spectroscopy and imaging of skin cancers.
Theoretical analysis on particle manipulation of the optical tweezers arrays system
Author(s):
Qin Li;
Wanli Feng;
Chu Wang;
Qun Cao;
Xiaoming Hu;
Dingguo Sha;
Jiaming Lin;
Dejun Zhu
Show Abstract
In biological scientific research, separating biological macromolecules or cells in liquid is always a
challenging job. Optical tweezers have been a valuable research tool since their invention in the 1980s. One of the
most important developments in optical tweezers in recent years has been the creation of two-dimensional arrays of
optical traps. In this paper, a method based on interference is discussed to form the gradient laser fields, which may cause
spatial modulation of the concentration of particles. The parameters related with the optical tweezers array are discussed
in detail and simulated by Matlab software to show the impact factor of the important parameters for the concentration
distribution of the particles. The spatial redistribution of particles in a laser interference field could be also predicted
according the theoretical analysis.
Single tapered fiber optical tweezers
Author(s):
Zhihai Liu;
Chengkai Guo;
Jun Yang;
Libo Yuan
Show Abstract
A single tapered fiber optical tweezers is demonstrated experimentally based on a fused tapered fiber probe. Yeast cells
immersed in water were trapped at the tip of the fiber probe and moved in 3 dimensions at a certain velocity. The
trapping force, both axial and transverse, can only be attributed to the force effect of the optical field emerging from the
end of the fiber probe. The output optical field was numerically simulated by using a BPM (beam propagation method)
method. It is qualitatively discussed that such optical field own the ability to form a 3-D optical trap.
A novel analysis method for near infrared spectroscopy based on Hilbert-Huang transform
Author(s):
Zhenyu Zhou;
Hongyu Yang;
Yun Liu;
Zongcai Ruan;
Qingming Luo;
Hui Gong;
Zuhong Lu
Show Abstract
Near Infrared Imager (NIRI) has been widely used to access the brain functional activity non-invasively. We use a
portable, multi-channel and continuous-wave NIR topography instrument to measure the concentration changes of each
hemoglobin species and map cerebral cortex functional activation. By extracting some essential features from the BOLD
signals, optical tomography is able to be a new way of neuropsychological studies. Fourier spectral analysis provides a
common framework for examining the distribution of global energy in the frequency domain. However, this method
assumes that the signal should be stationary, which limits its application in non-stationary system. The hemoglobin
species concentration changes are of such kind. In this work we develop a new signal processing method using
Hilbert-Huang transform to perform spectral analysis of the functional NIRI signals. Compared with wavelet based
multi-resolution analysis (MRA), we demonstrated the extraction of task related signal for observation of activation in
the prefrontal cortex (PFC) in vision stimulation experiment. This method provides a new analysis tool for functional
NIRI signals. Our experimental results show that the proposed approach provides the unique method for reconstructing
target signal without losing original information and enables us to understand the episode of functional NIRI more
precisely.
Detect the motion of green fluorescence proteins within living cell
Author(s):
Chen Wang;
Jinyuan Wang;
Guo Fu;
Guiying Wang;
Zhizhan Xu
Show Abstract
Single-molecule/particle tracking technology is becoming a powerful tool to the noninvasive study of membrane
property and membrane molecular processes. Here, we used total internal reflection fluorescence microscopy combined
with oblique illumination fluorescence microscopy to investigate green fluorescence protein within living cell. Total
internal reflection illumination allowed the observation of molecules in the cell membrane of living cell since the
penetrate depth is adjusted to about 100nm, and oblique illumination is allowed the observation of molecules/particles
both in the cytoplasm and apical membrane, which suggested this combination would be promising to investigate protein
dynamics through the whole cell. Not only individual protein molecule/particle tracks have been analyzed quantitatively
to reveal the motion of protein, but also statistical analysis has been done to substantiate the observation of protein
dynamics. Our data that involved up to 700 trajectories in several hundreds cells are indicated that at least four modes of
motion are presented, that is directed motion, normal diffusion (random walk), binding motion and corralled motion.
Detailed analysis as well as statistical analysis is presented in the paper.
Quantitative fluorescence resonance energy transfer measurements using microarray technology
Author(s):
Jiang Zhu;
Cheng Deng;
Guoliang Huang;
Yang Yang;
Shukuan Xu;
Zhonghua Dong;
Xiaoyong Yang;
Keith Mitchelson;
Jing Cheng
Show Abstract
Fluorescence resonance energy transfer (FRET) has found wide use in structural biology, biochemistry, and cell biology
for measuring intra- and inter-molecular distances in the 1-10 nm range and for obtaining quantitative spatial and
temporal information about the interaction of proteins, lipids, and DNA. The measurements of distances and interactions
are based on the calculation of the fluorescence transfer efficiency using some algorithms to process the acquired images
from several different filter sets. However, FRET measurements can suffer from several sources of distortion because of
cross talk between donor and acceptor fluorophores. In this paper, we measured the FRET efficiency on glass coverslips
using microarray technology and described an algorithm to analyze the FRET data obtained, which is corrected for the
cross talk due to spectral overlap of donor and acceptor molecules. Measurement of the interaction of the donor and
acceptor, which are mixed together or coupled to the respective 3'-end and 5'-end of a single-strand DNA are shown to
document the accuracy of the approach, and allow one to estimate cross talk between the different filter units and to
reveal the relationship of the FRET efficiencies of these two samples relative to the donor and acceptor concentrations.
A promising method based on surface plasmon resonance for quantitative analysis of biological samples
Author(s):
Zhonghua Dong;
Cheng Deng;
Shukuan Xu;
Jiang Zhu;
Yang Yang;
Xiaoyong Yang;
Guoliang Huang
Show Abstract
Surface plasmon resonance (SPR) technique is based on an optical measurement approach that is highly sensitive to the
refractive index unit (RIU) of the sample on its analysis surface. Here, we demonstrate the direct detection of proteins
and small molecules using an advanced SPR technology with a sensitivity that is as good as Fourier transform infrared
(FTIR) spectroscopy. Some quantitative results are reported in this paper.
Single dye molecules observed by total internal reflection fluorescence microscopy
Author(s):
Jinyuan Wang;
Guo Fu;
Chen Wang;
Li Liu;
Guiying Wang
Show Abstract
Total internal reflection fluorescence microscopy (TIRFM) was used to image single molecules with evanescent waves.
The molecules were excited by an evanescent wave with different intensities. Single molecules were imaged on
low-noise high-quantum-yield charge-coupled device (CCD) cameras. Two-step photobleaching behavior was observed.
Duration from fluorescent spots appearing to disappearing was counted. The duration was decided by the speed of
photobleaching. Peak intensity was counted as exciting intensity change. The proportion relationship between the
reciprocal of duration and exciting intensity was obtained. The emitted intensity and duration of fluorescein were
compared with GFP. A single molecules emit the same number photons was proved.
Optical imaging of TNF-a induced apoptosis pathway in living PC12 cells
Author(s):
Lan Zhang;
Da Xing;
Miaojuan Chen
Show Abstract
Tumor necrosis factor-α (TNF-α) elicits a wide range of biological responses, including neuronal apoptosis and
neuroprotection, and this functional pleiotropy is essentially determined by the individual molecular orchestration. Two
main pathways lead to apoptosis - the 'extrinsic' or death receptor-initiated pathway, and the 'intrinsic' or
mitochondrial pathway. In this study we firstly examine the signaling pathways involved in TNF-α induced apoptosis in
living PC12 cells by optical imaging. Our results show that the cleavage of BID has been monitored in real time using
fluorescence resonance energy transfer (FRET) technique after PC12 cells treated with TNF-α. Then we observe BAX
can't translocation to mitochondria during PC12 cells apoptosis induced by TNF-α, and that there is no any evidence of
cytochrome C release into cytosol during cell apoptosis. Our data support that TNF-α mediated PC12 cells apoptosis is
extrinsic apoptotic pathway which independent of mitochondria.
Dynamic activation of H-Ras induced by low power laser irradiation in living cells
Author(s):
Xuejuan Gao;
Da Xing;
Yihui Pei;
Fang Wang
Show Abstract
Low-power laser irradiation (LPLI) has been shown to promote cell proliferation in various cell types, yet the
mechanism of which has not been fully clarified. Studying the signaling pathways involved in the laser irradiation is
important for understanding these processes. The Ras/Raf/MEK/ERK (extracellular-signal-regulated kinase) signaling
pathway is a network that governs proliferation, differentiation and cell survival. Recent studies suggest that Ras/Raf
signaling pathway is involved in the LPLI-induced cell proliferation, but the dynamic activation of Ras in living cells
induced by LPLI has not been reported. In present study, to monitor the dynamic activation of H-Ras after LPLI
treatment in living cells in real time, Raichu-Ras reporter was utilized, which was constructed based on fluorescence
resonance energy transfer (FRET) technique. Our results show that the dynamic activation of H-Ras at the cell edges of
the plasma membrane is monitored during cell proliferation induced by LPLI (0.8 J/cm2) in serum-starved COS-7 cells
expressing Raichu-Ras reporter using FRET imaging on laser scanning confocal microscope, and that LPLI causes the
redistribution of H-Ras from the cytoplasm to plasma membrane. The same results are observed in EGF treated COS-7
cells. Taken together, LPLI induces the COS-7 cells proliferation by activated Ras.
High sensitive method detection of plant RNA viruses by electrochemiluminescence reverse transcription PCR
Author(s):
Ya-bing Tang;
Da Xing;
De-bin Zhu;
Xiao-ming Zhou
Show Abstract
It is well known that plant and animal viruses had widely spread the whole of world, and made a big loss in farming and
husbandry. It is necessary that a highly efficient and accurate virus's detection method was developed. This research
combines reverse transcription polymerase chain reaction (RT-PCR) technique with electrochemiluminescence method,
to detect plant RNA viruses for the first time. Biotin-probe hybridizes with PCR product to specific select the target for
detection, thus can avoid pseudo-positive result. TBR-probe hybridizes with PCR product to emit light for ECL detection.
Specific nucleic acid sequences (20bp) were added to 5' terminal all of the primers, which can improve the chance of
hybridization between TBR-probe and PCR product. At the same time, one of the PCR product chain can hybridize two
Ru-probes, the ECL signal is intensified. The method was used to detect Odntoglossum ringspot virus ORSV, Sugarcane
mosaic virus ScMV, Sorghum mosaic virus SrMV, and Maize dwarf mosaic virus MDMV, the experiment results show
that this method could reliably identity virus infected plant samples. In a word, this method has higher sensitivity and
lower cost than others. It can effectively detect the plant viruses with simplicity, stability, and high sensitivity.
Mitochondrion-mediated apoptosis induced by photofrin-PDT
Author(s):
Yunxia Wu;
Da Xing
Show Abstract
Apoptosis is an important cellular event that plays a key role in pathogeny and therapy of many diseases. The
mechanisms of the initiation and regulation of PDT-induced apoptosis are complex. Some PDT-associated apoptosis
pathways involved plasma membrane death receptors, mitochondria, lysosomes and endoplasmic reticulum (ER). In
order to determine the apoptosis pathway induced by Photofrin-PDT, we used fluorescence resonance energy transfer
(FRET) technique and probe SCAT3 to monitor the dynamics of caspase-3 activation after PDT treatment and also
measured caspase-8 activity. With laser scanning confocal microscopy, we found that Photofrin were localized primarily
in mitochondria, the primary targets of Photofrin-PDT. Formation of mitochondrial reactive oxygen species (ROS) was
detected within minutes after PDT treatment. This was followed by mitochondrial membrane potential (ΔΨm),
cytochrome c release, caspase-9 activity, caspase-3 activity and apoptosis. After PDT treatment, caspase-3 was activated
rapidly while caspase-8 remained inactivated. Our results indicated that PDT-induced apoptosis was initiated from
mitochondria pathway and independent of caspase-8 activation. The activation of caspase-3 by PDT started 20 minutes
after treatment and completed in about 15 minutes. PDT-induced apoptosis is directly initiated from mitochondria
pathway and not involved in the death receptors-dependent pathway. Our results demonstrated that FRET could be an
effective tool to determine PDT-induced apoptosis and other cell death mechanism.
The single cell analysis of HSP70 expression on tumor cell surface induced by PDT in living cells
Author(s):
Feifan Zhou;
Da Xing;
Wei Chen
Show Abstract
Heat shock protein70 (HSP70) is expressed plentifully in tumor cells, and it could regulate tumor immunity. Recent
studies show that PDT induces cell surface expression and release HSPs from the treated cells. HSPs have critical role in
the PDT-induced immune responses, but the dynamic of HSP70 in living cells induced by PDT has not been reported. In
present study, YFP-HSP70 was used to monitor the dynamic distribution of HSP70 in living cells in real time. With
confocal laser scanning microscope, we detected the dynamic distribution of HSP70 after PDT treatment. The results
show that HSP70 most localize in the cytoplasm of tumor cells, but few localize on cell surface, and that the cytoplasmic
HSP70 immediately translocated to the cell surface after Photofrin-PDT treatment. In addition, the surface-expressed
HSP70 remain unchanged and did not release from tumor cells during apoptotic process. Our data suggest that HSP70,
expressing on the cell surface after PDT treatment , may serves as a surface targets for immune cells and induced
immune responses to regulate the efficacy of PDT.
Enhancement of taxol-induced apoptosis by inhibition of NF-κB with ursorlic acid
Author(s):
Yunlong Li;
Da Xing
Show Abstract
Taxol is known to inhibit cell growth and triggers significant apoptosis in various cancer cells, and activation of
proliferation factor NF-κB during Taxol-induced apoptosis is regarded as a main reason resulting in tumor cells
resistance to Taxol. It has been found that ursorlic acid can inhibit the activation of NF-κB. In order to study whether
ursorlic acid can enhance the Taxol-induced apoptosis, we use fluorescence resonance energy transfer (FRET) technique
and probe SCAT3 to compare the difference of caspase-3 activation between Taxol alone and Taxol combined ursorlic
acid. With laser scanning confocal microscopy, we find that ursorlic acid, a nontoxic food component, sensitizes
ASTC-a-1 cells more efficiently to Taxol-induced apoptosis by advanced activation of caspase 3. The result also
suggests that there would be a synergistic effect between Taxol and ursorlic acid, and the more detailed mechanism of
synergistic effect needs to be clarified further, such as the correlations among NF-κB, Akt, caspase 8, which leads to the
advanced activation of caspase 3 during combined treatment of Taxol and ursorlic acid. Moreover, this may be a new
way to improve Taxol-dependent tumor therapy.
Single cell analysis demonstrates a rapid activation of bax in mitochondrion mediated-PDT apoptosis
Author(s):
Qingling Wan;
Da Xing;
Yunxia Wu
Show Abstract
Apoptosis is a very important cellular event that plays a key role in pathogeny and therapy of many diseases. One of the
important modes cell death by photodynamic therapy (PDT) is apoptosis. The translocation of Bax from the cytosol into
the mitochondrial outer membrane is a central event during apoptosis. In this study, we detected the kinetics of Bax
activation in the cells with different photosensitizers treatments. Using laser scanning confocal microscopy, we found
that Photofrin were localized primarily in mitochondria and N-aspartyl chlorine e6 (NPe6) preferentially localized to
lysosomes. The results showed Bax can be activated and translocated from the cytosol to mitochondria by Photofrin-PDT
treatment but not by NPe6-PDT treatment in ASTC-a-1 cells. The activation of Bax started 15 minutes after Photofrin-
PDT treatment and the process of activation completed within 45 minutes. These results indicated that the initiation and
process of Bax activation are different corresponding to different sublocalization photosensitizers treatments. Our data
suggests that different sublocalization photosensitizers in PDT treatments photodamaged different organelles and will
trigger various apoptotic pathways in PDT treatment.
Temporal and spatial characteristics of bid and bax translocation during UV-induced apoptosis
Author(s):
Yinyuan Wu;
Da Xing;
Lei Liu D.D.S.;
Tongsheng Chen
Show Abstract
UV irradiation is a DNA-damage agent that triggers apoptosis through both the membrane death receptor and the
mitochondrial apoptotic signaling pathways. Bid and Bax are two important proapoptotic members of the Bcl-2 family,
localize largely in the cytoplasm and redistribute to mitochondria in response to most apoptotic stimuli. Cells deficient in
Bax are resistant to UV-induced apoptosis, cells deficient in Bid are less susceptible than normal cells in response to
DNA damage. Thus, studying characteristics of Bid and Bax translocation by UV irradiation is very important for us to
understand the cellular signaling mechanisms mediating UV-induced apoptosis. In this study, to investigate Bid and Bax
translocation in real time in a single cell by UV irradiation, we transfected Bid-CFP, YFP-Bax and DsRed-Mit into
human lung adenocarcinoma cells (ASTC-a-1), then observed temporal and spatial characteristics of Bid and Bax
translocation by laser confocal scanning microscope imaging technique. Our results showed that Bax translocation was
earlier than Bid translocation and the average duration of Bax translocation was about 20-30 min during UV-induced
apoptosis.
Application of fluorescence labeled liposome nanoparticles in the cell imaging
Author(s):
Jianbing Hu;
Huimin Li;
Xiaoxiao He;
Ping Gong;
Kemin Wang;
Shouchun Zhang
Show Abstract
Fluorescence labeled liposome nanoparticles were prepared by dispersion of film method. The size of nanoparticles was
around 50 nm. DPPE-FITC synthesized in our lab was used to label the liposome nanoparticles. Anti-cytokeratins 19
antibody was connected to the surface of the fluorescence liposome nanoparticles. After incubation with MGC cells and
COS-7 cells for 30 min, MGC cells were selectively recognized by anti-cytokeratins 19 antibody modified liposome
nanoparticles and well imaged under laser confocal microscope. This fluorescence labeled liposome nanoparticles is
expected to have good applications in cell recognition and tumor diagnosis.
Light-induced damage and its diagnosis in two-photon excited autofluorescence imaging of retinal pigment epithelium cells
Author(s):
Danni Chen;
Junle Qu D.D.S.;
Gaixia Xu;
Lingling Zhao;
Hanben Niu
Show Abstract
In this paper, a novel method for the differentiation of the retinal pigment epithelium (RPE) cells after light-induced
damage by two-photon excitation is presented. Fresh samples of RPE cells of pig eyes are obtained from local
slaughterhouse. Light-induced damage is produced by the output from Ti: sapphire laser which is focused onto the RPE
layer. We study the change of the autofluorescence properties of RPE after two-photon excitation with the same
wavelength. Preliminary results show that after two-photon excitation, there are two clear changes in the emission
spectrum. The first change is the blue-shift of the emission peak. The emission peak of the intact RPE is located at
592nm, and after excitation, it shifts to 540nm. It is supposed that the excitation has led to the increased autofluorescence
of flavin whose emission peak is located at 540nm. The second change is the increased intensity of the emission peak,
which might be caused by the accelerated aging because the autofluorescence of RPE would increase during aging
process. Experimental results indicate that two-photon excitation could not only lead to the damage of the RPE cells in
multiphoton RPE imaging, but also provide an evaluation of the light-induced damage.
Spectral resolved imaging of biological samples
Author(s):
Jianxin Chen;
Shuangmu Zhuo;
Qilian Zou;
Tianshu Luo;
Xingshan Jiang
Show Abstract
The spectral resolved imaging technique has a typical characteristic that it allows simultaneous recording of real-color
RGB image representation and corresponding spectra. In this paper, we present a nonlinear spectral resolved imaging
approach based on two-photon excited autofluorescence and second harmonic generation of biological tissues to
elucidate microstructure and spectroscopic features of unstained rabbit arterial wall. Coupled to the image-guided
spectral analysis method, we use a series of recorded nonlinear spectral resolved images excited by a broad range of laser
wavelengths (730-910nm) to identify five components in unstained rabbit arterial wall including in NADH, elastin,
flavin, porphyrin derivatives and collagen. Using the combination of a nonlinear spectral resolved imaging approach and
two-channel synchronized detection, we obtained high contrast 2-D and 3-D images of collagen and elastic fiber in the
arterial wall. Our results demonstrate that simultaneously linking a nonlinear spectral resolved imaging approach with
the image-guided spectral analysis method and multi-channel synchronized detection technique is a very useful method
because it can in tandem acquire the structural modifications of different tissue components and quantitatively record the
change of corresponding emission signal. This method has the potential to provide more comprehensive diagnostic
information for determining tissue pathology which associated with mechanical properties of aorta wall and
pharmacodynamical studies of vessels.
Study on the autofluorescence profiles of iris pigment epithelium and retinal pigment epithetlium
Author(s):
Gaixia Xu;
Junle Qu D.D.S.;
Danni Chen;
Yiwen Sun;
Lingling Zhao;
Ziyang Lin;
Zhihua Ding;
Hanben Niu
Show Abstract
Transplantation technique of retinal pigment epithelium has been noticeable in recent years and gradually put into
clinical practice in treatment of retinal degenerative diseases. Generally, immunological, histochemical, and physical
methods are used to study the iris pigment epithelium (IPE) and retinal pigment epithelium (RPE) cells, which need
complex sample preparation. In this paper, we provided a simple autofluorescence microscopy to investigate the fresh
porcine IPE and RPE cells without any pretreatment. The results showed that the morphology and size of both were
similar, round and about 15 μm. The main flourophore in both cells was similar, i.e. lipofuscin. In additional, the
autofluorescence spectrum of RPE shifted blue after light-induced damage by laser illuminating. Because it was easier
for IPE to be damaged by laser than for RPE, and the power of one scanning operation to get a full image was strong
enough to damage IPE sample, we hadn't get any satisfied autofluorescence spectrum of IPE.
Identification of endogenous flurophores in the layered retina
Author(s):
Gaixia Xu;
Danni Chen;
Yiwen Sun;
Junle Qu D.D.S.;
Ziyang Lin;
Zhihua Ding;
Hanben Niu
Show Abstract
In this paper, we measured and analyzed the characteristic of endogenous fluorophores in porcine layered retina by using
advanced fluorescence spectroscopy and microscopy imaging technology. It was found that there were obvious contrasts
corresponding to the different layers of retina, which may be important for fundus disease diagnosis. The retinal pigment
epithelium cells exhibited strong autofluorescence with as emission peak of 600±10nm when excited with 860-nm light.
The emission peak of photoreceptors was at 652±5nm, and the emission peak of retinal vessels layer was weak and at
640~700nm, when excited with 488-nm light. Autofluorescence images of three layers of retina were obtained using the
same setup. We concluded that the main endogenous fluorophore in PRE was lipofuscin and that in retinal vessels was
porphyrin. What's more, the FMHW (full width at half. maximum) of retinal fluorescence spectrum was broad, which
suggested that there wasn't only one endogenous fluorophores of tissues excited.
A microarray scanner for the real-time quantitative detection
Author(s):
Quanjun Liu;
Ying Zhuang;
Lingwei Wu;
Zhongwei Wu;
Song Hu;
Zuhong Lu
Show Abstract
The real-time and quantitative detection assay is important for the gene detection. With the TaqMan probes for the
detection based polymerase chain reaction (PCR), four targets could be checked in a single process in solution assay. A
new method is developed to immobilize the TaqMan probes on a microarray, which could be used to the multi-target
gene fragment quantitative detection with PCR. A new type microarray scanner is designed for the assay. A thermocycler
system was built into the scanner platform. A new type of the vessel sealed with the gene amplification solution which
could perform the thermo-cycling and scanning. To decrease the background intensity a confocal system was used as the
fluorescent intensity detection in the scanner. To calculate the gene quantity, a standard liner graph was draw with the
fluorescent intensity versus the cycles. From the standard liner, the quantity of the original gene fragment could be
calculated in time with the cycles. This scanner offers the great advantage of real-time quantitative detection of DNA
targets in a microarray.
Five-dimensional multifocal multiphoton microscopy
Author(s):
Lixin Liu;
Junle Qu D.D.S.;
Lei Wang;
Ziyang Lin;
Zhe Fu;
Baoping Guo;
Wenqing Liu;
Hanben Niu
Show Abstract
We present a novel 5-dimensional (5-D) MMM system that is based on a microlens array for producing discrete
excitation spots array, a prism for 2-dimensional (2-D) spectral dispersion and a specially designed picosecond streak
camera for providing simultaneous temporal and spectral resolutions, which enables the acquisition of fluorescence
lifetime information of any spectrum within the whole spectra in only one measurement. The near-infrared light from a
mode-locked titanium: sapphire femtosecond laser is split into an array of beams that are transformed into an array of
high-aperture foci at the sample. A time- and spectrum-resolved image of 3×3 foci on the sample can be obtained with a
snapshot. By translating the sample stage laterally and axially and implementing a dedicated image reconstruction
algorithm in the control system, 5-D data sets that combine temporal and spectral resolutions and 3-dimensional (3-D)
spatial coordinates can be obtained. The spectrum-resolved and depth-resolved fluorescence lifetime microscopic images
are demonstrated. Preliminary results indicate that the system has high temporal, spectral and spatial resolutions and
holds potential for providing high image acquisition rate.
Two-photon excited fluorescence imaging of cell spindles for developmental biology
Author(s):
Liang Gao;
Wenjia Bai;
Lei Jin;
Ping Xue;
Hui Ma;
Dieyan Chen
Show Abstract
By integrating two-photon excited fluorescence (TPEF) technique into confocal optical system, TPEF images of zygote
spindles of ICR (Internal Control Region) rats have been obtained in high resolution for the first time. Experimental
results demonstrate the validity of TPEF as an efficient probe in investigating cell spindles at early embryonic
developmental stage.
Data and image processing for a simultaneous time-and spectrum-resolved multifocal multiphoton microscopy
Author(s):
Zhe Fu;
Junle Qu D.D.S.;
Ziyang Lin;
Lixin Liu;
Baoping Guo;
Hanben Niu
Show Abstract
A Simultaneous Time- and Spectrum-Resolved Multifocal Multiphoton Microscopy (STSR-MMM) system has been
developed for the acquisition of fluorescence lifetime information of any spectrum of the biological samples in only one
measurement. The near-infrared light from mode-locked titanium: sapphire femtosecond laser is split with a microlens
array into an array of beams that are transformed into an array of high-aperture foci at the sample for parallel
multiphoton excitation. The Gaussian shape of the excitation beam results in non-uniformity and asymmetry of the
excitation foci array and also of the reconstructed fluorescence image. A coefficient matrix has been presented for the
correction of the non-uniformity and asymmetry in the fluorescence image. Data acquisition and image processing
methods have also been investigated to increase the image acquisition speed and improve the reconstruction of time- and
spectrum-resolved fluorescence image. The methods for obtaining fluorescence intensity image, spectrally resolved
intensity image and spectrally resolved lifetime image are also presented.
Study the autofluorescence of microalgae inducted by laser using laser scanning confocal microscope
Author(s):
Lin Ou;
Hui-ru Zhuang;
Rong Chen;
Jin-pin Lei;
Xiang-ying Huang;
Yan Tian;
Shen Lin;
Li-jiang Wang
Show Abstract
In this present paper, the microalgae irradiated by Nd:YAP laser are observed using Laser Confocal Scan microscope,
and the auto fluorescence of microalgae cells is analyzed with quantitative analysis system, so as to investigate the effect
of auto fluorescence alteration on growth of irradiated microalgae. Method: Platymonas subcordiformis, Phaeodactylum
tricormutum and Isochyrsis zhanjiangensis are irradiated by Nd:YAP laser with 10w at 1341nm, irradiating time:12s, 30s,
35s and 55s. On Lambda Scan mode, the auto fluorescence images and fluorescence spectra of algae cells are obtained
by the excitation 488nm (Ar+ laser). Result: there are two summit peaks, 489.8nm and 680.9nm, for Platymonas
subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis fluorescence spectrum. Contrast to the CK,
the peak positions of fluorescence of irradiated algae cells is similar to the whole while the peak light intensity alters. On
irradiation of promoting dose, however, the auto fluorescence intensity is enhanced more than control, with different type
of microalgae, the different fluorescence intensity are shown in the analysis, and all of the microalgae pigment bodies
change can be seen also. Conclusion: Physiological incentive effect of irradiated microalgae can be given expression on
fluorescence characteristics and fluorescence intensity alteration of cells.
Full-field OCT for developmental biology
Author(s):
Rui Wang;
Ping Xue;
Wenjia Bai;
Dieyan Chen
Show Abstract
In this paper, we developed a full-field OCT system using thermal light as the low-coherence light source. A well-known
Linnik interferometer configuration was used. Broad spectral width of the thermal light 450-650nm was used to achieve
high axial resolution of 1.1&mgr;m in biological sample for OCT imaging. Two water immersion objectives of 0.5N.A were
used to balance the dispersion and a transverse resolution of 0.7μm was obtained. With a fast machine-coding algorithm,
system sensitivity of more than 80dB and imaging rate as high as 18frame/s with 500x500 pixels per frame could be
achieved. Mouse embryos were imaged in vivo with full-field OCT at different depth for the developmental study. Useful
information for pre-implementation genetic diagnosis (PGD) was obtained by image analysis and segmentation. As far as
known, for the fist time, 3D images of mammalian embryos were obtained with full-field OCT without the need of dye
labeling.
The early study on the inspection of tongue of the traditional Chinese medicine using optical coherence tomography
Author(s):
Hui-Qing Zhong;
Chang-Chun Zeng;
Zhou-Yi Guo;
Yong-Hong He;
Rui-Kang Wang;
Song-Hao Liu
Show Abstract
Inspection of tongue is an age-old technique used by Traditional Chinese Medicine (TCM) practitioners to determine a
patient's health status. Because tongue examination is a subjective and inaccurate diagnostic method, a scientific tool
which can provide objective and accurate information is needed to assist the TCM practitioners in their practice. The
purpose of the study was to examine the feasibility of developing a glossoscopy from an optical coherence tomography
(OCT) imaging system. In the present study, an OCT system was used to examine the tongue of the rat. After
examination, the tongue was surgically removed, sectioned by a microtome and put on a glass slide for histological
examination. The slides were examined under a bright-field microscope. Results of the OCT imaging studies showed that
the OCT system was capable of showing the images of three distinct regions of the tongue: the tongue coating layers, the
interface between the tongue coating and the tongue body, and the tongue body. It was also possible to assign an index
number to each of the coating layers. When the tongue tissue was examined under a microscope, three separate regions
of the tongue also were visible. Results of this pilot study shows that the OCT potentially can be developed into a
glossoscopy for clinical application in TCM practice.
The mechanism and influencing factors on photodynamic purging of leukemia cells
Author(s):
Zhongming Li;
Zhenxi Zhang
Show Abstract
The paper compared the response of HL60 cells with peripheral blood mononuclear cell (PBMC) after 5-ALA PDT for
different periods of time and then followed by irradiating with different wavebands for different fluences. The results of
parameter experiments were obtained: 1 × 105/mL HL60 cell was incubated with 1 mmol/L ALA in dark for 4 h and the
maximum fluorescence of PpIX level appeared; then irradiated with 410 nm (4 mW/cm2) for 14.4 J/cm2 and maximum
photodamage to membrane and mitochondrial function of HL60 cell resulted. Analyzed the experimental results of
references, we got that the effect of photodynamic purging of leukemia cells may be modulated by the leukemia cell type;
the photosensitizer's type, dose, and its location point; the incubation time and condition; the light wavelength and its
dosage. If the light is delivered at a high rate, significant heating of a molecule and its surrounding may take place. A too
low dosage has no effect at all or will result in high relapse rate due to the presence of cancer cells. The wavelength and
intensity of light required to carry out photopurging is determined by the absorption properties of the photosensitizer.
The light dose actually received by the photosensitizer and tissue may be higher or lower depending on the manner of
irradiation.
Experiment and mechanism investigation on acid resistance of Nd:YAG laser treated enamel
Author(s):
Li Liu;
Zhengjia Li
Show Abstract
The effectiveness of Nd:YAG laser treatment on in vitro acid resistance of human enamel was studied. After surface
polishing, enamel blocks irradiated by different power laser and control group were put into 5ml of lactate buffer
solution (0.1mol/L), which was in water of 37°C for 72 hours. The hardness and morphology of enamel surface were
investigated by microhardness meter and scanning electron microscopy. Compared with control, the group with 0.3W
laser treatment has the least caries lesion (p<0.001). At the same time, the mechanism of caries prevention and acid
resistance by laser was discussed in detail. We drew a conclusion that the change of contents in enamel and crystal
orientations and partial decomposition of the organic matrix might be the main reason for enhancing acid resistance.
And best caries inhibition could be achieved when the temperature rising of enamel surface was in the range of
300~400°C by laser parameters being controlled suitably.
Photobiomodulation on alcohol induced dysfunction
Author(s):
Zheng-Ping Yang;
Timon Cheng-Yi Liu;
Yan Zhang;
Yan-Fang Wang
Show Abstract
Alcohol, which is ubiquitous today, is a major health concern. Its use was already relatively high among the youngest
respondents, peaked among young adults, and declined in older age groups. Alcohol is causally related to more than 60
different medical conditions. Overall, 4% of the global burden of disease is attributable to alcohol, which accounts for
about as much death and disability globally as tobacco and hypertension. Alcohol also promotes the generation of
reactive oxygen species (ROS) and/or interferes with the body's normal defense mechanisms against these compounds
through numerous processes, particularly in the liver. Photobiomodulation (PBM) is a cell-specific effect of low intensity
monochromatic light or low intensity laser irradiation (LIL) on biological systems. The cellular effects of both alcohol
and LIL are ligand-independent so that PBM might rehabilitate alcohol induced dysfunction. The PBM on alcohol
induced human neutrophil dysfunction and rat chronic atrophic gastritis, the laser acupuncture on alcohol addiction, and
intravascular PBM on alcoholic coma of patients and rats have been observed. The endonasal PBM (EPBM) mediated by
Yangming channel, autonomic nervous systems and blood cells is suggested to treat alcohol induced dysfunction in terms
of EPBM phenomena, the mechanism of alcohol induced dysfunction and our biological information model of PBM. In
our opinion, the therapeutic effects of PBM might also be achieved on alcoholic myopathy.
The photodamage effect and ROS generation induced by PDT with HMME in MCF-7cells in vitro
Author(s):
Huijuan Yin;
Xiaoyuan Li;
Jianzhong Liu;
Yan Li
Show Abstract
Hematoporphyrin monomethyl ether (HMME) is a novel and promising porphyrin-related photosensitizer for
photodynamic therapy (PDT). We use the human breast cancer MCF-7 cells to investigate the photodamage effect of
HMME and reactive oxygen species (ROS) generation in HMME-PDT. Methods: The growth rates of MCF-7 cells at 24h
after irradiation by 532nm laser with HMME of 5~20μg/ml and light dose of 0.3~4.8J/cm2 were determined by CCK-8
assays. Hoechst33342 staining was used to investigate the morphological change of the tumor cell. Flow cytometry
combined with dual Annexin V/PI staining was used to identify the death mode of the cells following PDT. The changes of
ROS labeled by DCFH-DA were observed by Laser Scanning Confocal Microscopy (LSCM). Our results show that
HMME-based PDT induced significant cell death, and the photocytotoxity to MCF-7 cells is dose-dependent at the range
of HMME concentration 5~20μg/ml and the light dose 0.3~4.8J/cm2. The nucleolus underwent apoptosis and/or necrosis
observed by LSCM with Hoechst33342 staining. The necrosis and apoptosis rate were 16.0% and 12.4% respectively by
FCM, showing the number of necrosic cells was more than that of apoptosis. There was an intense increase of fluorescence
intensity standing for ROS generation within 30min post-PDT, and the peak was at about 10min after PDT. Our results
suggest that HMME-PDT could inhibit the proliferation of MCF-7 cells remarkably. Because the MCF-7 cells lack
procaspase-3, the apoptosis rate is lower. ROS played an important role in the photodamage with HMME.
80-W green KTP laser used in photoselective laser vaporization of the prostrate by frequency doubling of Yb3+ -doped large-mode area fiber laser
Author(s):
Hongxing Xia;
Zhengjia Li
Show Abstract
Photoselective laser vaporization of the prostate (PVP) is the most promising method for the treatment of benign
prostatic hyperplasia (BPH), but KTP lasers used in PVP with lamp-pumped are low efficient .To increase the efficiency ,
we develop a 80-W, 400kHz, linearly polarized green laser based on a frequency-doubled fiber laser. A
polarization-maintaining large-mode area (LMA) fiber amplifier generate polarized 1064nm fundamental wave by
amplifying the seed signal from a composite Cr4+:YAG-Nd3+:YAG crystal fiber laser. The fundamental wave is injected
into a KTP crystal with confined temperature management to achieve second harmonic generation (SHG). The overall
electrical efficiency to the green portion of the spectrum is 10%.80-W maintenance-free long-lifetime KTP laser obtained
can well satisfy the need of PVP.
Based on photo-electro position sensitive detector contour damage diagnosis measurement system research
Author(s):
Tianze Li;
Jin Shen;
Shuyun Wang
Show Abstract
Based on the lateral photo effect of the semiconductor photoelectric position sensitive device, Developing a new kind
of photo-electro position sensitive detector as the receiver of the laser beam, taking the laser as the launcher, and using
optical lens, light filter .etc, we have designed a new kind of 3D non-contact optical measurement system with high
accuracy and high resolution. The characteristics of this system are demonstrated as: very high response speed; very
high position resolution; the position output has nothing to do with the intensity of the light spot as well as the size of
it, only if the center of gravity of it is related; And it can detect the intensity and the position of the incident light spot at
the same time, etc. On the basis of the ruled lines of the Cartesian axes located on the object that is measured, it can
produce the contour of the object, which provides a optical detecting method that can measure the marginal date
accurately for detecting irregular shape and early surgical analysis and diagnosis. This measurement system has very
high application value for the clinical diagnosis. Finally, it has analyzed the factors affecting system precision and
causes of the system errors, and has provided the experimental result and several important conclusions.
Up-converting phosphor technology-based biosensor
Author(s):
Kun Yu;
Lei Zhou;
Lei Liu;
Lihua Huang;
Zhongqiang Yan;
Yongkai Zhao;
Ruifu Yang;
Huijie Huang
Show Abstract
A new generation of Up-converting phosphor technology-based biosensors (UPT-based biosensor) has been developed
for immunoassay, where a kind of novel Up-converting phosphor (UCP) particle serves as the biological marker. Its
control system is based on a micro-computer control unit instead of a personal computer, which results in low power
consumption, high reliability and portability for field detection. By detecting the content of the UCP on the test strip, the
system figures out the concentration of the biological molecular of interest, which can be used in field examination of
biological analytes. In this paper, a series concentration of standard samples have been tested by the biosensor, which is
proved to have higher sensitivity (~ng/ml), higher stability (CV<3~5%), better linear relationship and an excellent
correlation (R2≥0.95). The UPT-based biosensor has stable, reliable and sensitive performances. It can meet the need of
various rapid bioassay applications.
Effect of LED irradiation on the expression of MMP-3 and MMP-13 in SW1353 cells in vitro
Author(s):
Chang-chun Zeng;
Zhou-yi Guo;
Feng-xue Zhang;
Wen-di Deng;
Song-hao Liu
Show Abstract
Matrix Metalloproteinase (MMP) plays an active role in remodeling cartilage in osteoarthritic cartilage. To find an
effective method of prevention of osteoclasia, this in vitro study focuses on the expression of MMP-3 and MMP-13 in
the SW1353 cells by LED irradiation. The human chondrosarcoma cell line SW1353 were stimulated with the
proinflammatory cytokine IL-1beta or tumor necrosis factor-alpha (TNF-alpha), and were received the irradiation of
LED (632nm, 4mW/cm2). The cell count was assessed over a 96-hour period by using Trypan blue dye exclusion assay,
and the cell activity was evaluated with a Cell Counting Kit-8 Assays. The subsequent expression of MMP-3 and
MMP-13 was quantified. Results of this experiment showed that the cultural cell activity was decreased, and the
expression of MMP-3 and MMP-13 was increased by being stimulated with IL-1beta or TNF-alpha. After received LED
irradiation, the death rate of cultural cell was increased and the expression of MMP-3 and MMP-13 was decreased
significantly. The present study concluded that particular LED irradiation stimulates SW1353 cell proliferation activity
and inhibit the MMP-3 and MMP-13 enzymatic activity. These findings might be clinically relevant, indicating that the
low power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.
Membranotropic photobiomodulation on red blood cell deformability
Author(s):
Gang-Yue Luo;
Yan-Ping Zhao;
Timon Cheng-Yi Liu;
Song-Hao Liu
Show Abstract
To assess modulation of laser on erythrocyte permeability and deformability via cell morphology changes, healthy
human echinocytes with shrinking size and high plasmic viscosity due to cellular dehydration were treated with 1 mW, 2
mW, 3 mW, and 5 mW laser power exposure respectively. Image analyzing system on single intact erythrocyte was
applied for measuring comprehensive cell morphological parameters (surface area, external membrane perimeter, circle
index and elongation index) that were determined by the modulation of erythrocyte water permeability and deformability
to detect relationship between erythrocyte water permeability alteration and deformability. Our preliminary experiment
showed that exposure under light dose of 5 mW for 5 min could induce more active erythrocyte swelling and
deformation. water channel aquaporin-1(AQP-1) was inhibited by the incubation of HgCl2 in the presence and absence of
5 mW laser irradiation. The result suggested that osmotic water permeability is a primary factor in the procedure of
erythrocyte deformability. In addition, no modulation of laser(5mW) on erythrocyte deformability had been found when
the echinocytes were cultured with GDP-β-S (G protein inhibitor).
Absorption spectrum characteristic of chorophyll derivatives photosensitizer CPD3
Author(s):
Fenghua Xiang;
Hui Liu;
Youshan Lu;
Ping Chen D.D.S.;
Guoqing Tang
Show Abstract
Absorption spectrum of CPD3 is determined. There are two absorption bands all in absorption spectrum, the
maximal absorption of band B is at 395nm in 0.9% NaCl solution and TE buffer solution, the band Q is locating at
677nm and 651nm respectively in solvents above. The order of magnitude of extinction coefficient is 104 in both
solvents. the absorption peak of CPD3-DNA mix solution have 6nm and 23nm red shift for band B and band Q
respectively compared with pure CPD3 in 0.9% NaCl solution, this indicates that interaction between
photosensitizer and DNA occurring. Time series data of absorption for CPD3-DNA mix solution supports the
interaction viewpoint further, and the full action time is about 90mins. The type of interaction needs a further
investigating. Stronger absorption in red region and the interaction with DNA suggests that CPD3 will have a bright
future in photodynamic therapy.
Monitoring of hemoglobin glycation using spectral and refraction measurements
Author(s):
Ekaterina N. Lazareva;
Valery V. Tuchin
Show Abstract
This study is focused on the determination of the real and imaginary parts of the complex refractive index of
oxyhemoglobin and deoxyhemoglobin solutions (1.6 g/l) at different concentrations of glucose (from 0 to 1000 mg/dl
with a step of 100 mg/dl) from a few hours to over one week of incubation. The real part was measured using Abbe
refractometer. Theoretical values of real part of refractive index were calculated supposing non-interacting hemoglobin
and glucose molecules. The imaginary part was determined using transmittance measurements at the wavelength range
from 500 nm to 1000 nm. It is shown that the real and imaginary parts of the complex refractive index measurements
have a potential for the evaluation of glycated hemoglobin amount.
A novel method for rapid and non-invasive detection of plants senescence using delayed fluorescence technique
Author(s):
Lingrui Zhang;
Da Xing;
Junsheng Wang;
Lizhang Zeng;
Qiang Li
Show Abstract
Plants senescence is a phase of plants ontogeny marked by declining photosynthetic activity that is paralleled by a
decline in chloroplast function. The photosystem II ( PSII ) in a plant is considered the primary site where light-induced
delayed fluorescence (DF) is produced. With the leaves of Catharanthus roseus (Catharanthus roseus (L.) G.Don) as
testing models, we have studied the effects of plants senescence induced by dark and/or exogenous hormones treatments
on characteristics of DF by using a home-made portable DF detection system, which can enable various DF parameters,
such as DF decay kinetic curve and DF intensity, to be rapidly produced for the plants in a short time. The results show
that the changes in DF intensity of green plants can truly reflect the changes in photosynthetic capacity and chlorophyll
content. Therefore, DF may be used an important means of evaluating in vivo plants senescence physiology. The changes
in DF intensity may provide a new approach for the rapid and early detection of plants senescence caused by age or other
senescence-related factors. DF technique could be potential useful for high throughput screening and less
time-consuming and automated identifying the interesting mutants with genetic modifications that change plants
senescence progress.
The luminescence properties of CdS nanoparticles labeled on DNA molecules
Author(s):
Weilin Shi;
Xiying Ma
Show Abstract
We present the luminescence properties of CdS nanoparticles conjugated with active DNA molecules. Having the action
of activators, CdS nanoparticles combine with DNA molecules easily and tightly. The fluorescence from CdS
nanoparticles is characteristics of bright spots under dark optical microscopy, indicating that CdS nanopaticles can be
used labeling DNA molecules. Strong photoluminescence emission of A-DNA-CdS keeps relatively steady at room
temperature in terms of the time behavior of optical bleaching, showing that CdS nanoparticles are suitable to long time
biological analysis and detection.
Delayed luminescence spectra detection of AflatoxinB1 contamination in whole rice
Author(s):
WenLi Chen D.D.S.;
Zhou Quan;
Da Xing
Show Abstract
Employing a luminescence spectrometer the usefulness of light-induced delayed luminescence (DL) for the
detection of aflatoxinB1 (AfB1) contamination in whole rice was studied. Rice was artificially contaminated with
Aspergillus flavus (7.5×105 conidia/ml) and incubated for 0 - 72 h. The DL spectra of contaminated rice were
obtained by a luminescence spectrometer. The correlation between the spectra and contamination levels was
established. The DL intensity has a negative correlation with the AfB1 concentration. The results suggested that the
DL technique might be useful for the rapid and non-invasive evaluation of AfB1 contamination levels in whole rice.
Design and theoretical investigation of a digital x-ray detector with large area and high spatial resolution
Author(s):
Jianbao Gui;
Jinchuan Guo;
Qinlao Yang;
Xin Liu;
Hanben Niu
Show Abstract
X-ray phase contrast imaging is a promising new technology today, but the requirements of a digital detector with large
area, high spatial resolution and high sensitivity bring forward a large challenge to researchers. This paper is related to
the design and theoretical investigation of an x-ray direct conversion digital detector based on mercuric iodide
photoconductive layer with the latent charge image readout by photoinduced discharge (PID). Mercuric iodide has been
verified having a good imaging performance (high sensitivity, low dark current, low voltage operation and good lag
characteristics) compared with the other competitive materials (α-Se,PbI2,CdTe,CdZnTe) and can be easily deposited on
large substrates in the manner of polycrystalline. By use of line scanning laser beam and parallel multi-electrode readout
make the system have high spatial resolution and fast readout speed suitable for instant general radiography and even
rapid sequence radiography.
Measurement of optical absorption coefficient of bio-tissue at 532nm wavelength
Author(s):
Chuyun Huang;
Zhengjia Li;
Yucheng Yao;
Yanyan He
Show Abstract
Laser technology has succeeded in medical application. High power 532nm laser has applied in prostate ablation and
other clinic application. To understand optical property of bio-tissue at 532nm wavelength, a method of monitoring
surface temperature was used to measure absorption coefficient of gall-stone, porcine liver and canine prostate. The
absorption coefficient of gall-stone is about 62cm-1 at 532nm wavelength, and those of porcine liver and canine prostate
are about 13cm-1 and 5.4cm-1, respectively. These results help to understand the optical property of bio-tissue and offer
theoretic reference for optical dosimetry in clinic application.
Discussion of evaluating methods for photorejuvenation
Author(s):
Yue Yun Wang;
Rong Chen;
XiaoHua Liao;
Yong Zeng Li
Show Abstract
Photorejuvenation is a promising technique for esthetics. But evaluating approach for efficacy of photorejuvenation is
relatively behind demand. In this study, after discussion of current techniques, a novel evaluating method for
photorejuvenation which combines reflectance and fluorescence spectroscopy is proposed. Laser induced
autofluorescence spectroscopy can be used to detect biochemical information from depth of skin. Tristimulus values
which reflect the color of skin can be obtained by diffuse reflectance spectroscopy. So combination of the reflectance and
fluorescence spectrum is expected to be a promising tool for evaluating efficacy of photorejuvenation.
The analysis and practical application about the effect of intra-vascular laser irradiation on C-C bond
Author(s):
Can-Bang Zhang;
Zhi-Fu Dai;
Li-Li Zhang;
Jia-Jin Tian;
Ling-Yun Zhou
Show Abstract
C-C bond is the most common kind of interactions in biological molecules. For example, the molecules of cholesterol
and fibrinogen are connected with C-C bonds. We analysis the effect of Laser onto C-C bond in medical cure case by the
method of Intra-vascular Laser Irradiation on blood (ILIB), and in theory a new model of "Laser-(C-C)" inharmonic
oscillator is constructed on the base of quantum mechanics. Furthermore, we investigate the helpful influence of ILIB
through sixty-two cases of brain-thrombus.
Influencing factors in the measurement of intracellular free calcium
Author(s):
Yuanyuan Li;
Sujuan Zhang;
Dan Sun;
Ying Qu;
Xinliang Zheng
Show Abstract
One of the popular methods for measurement of intracellular free calcium ([Ca2+]i) is ratiometric fluorescence technique.
Rmax and Rmin play an important role in the calibration of [Ca2+]i measurement. The purpose of this study was to analyze
influencing factors in the [Ca2+]i measurement. Rmax and Rmin deduced from theory had a hyperbolic relation with the
ratio of Cf and Cb (Cf: free indicator concentration; Cb: Ca2+-bound indicator concentration). In experiments, using
radiometric fluorescence imaging system, they were measured separately in two types of cell lines in concentration
gradient (2×105cells/ml, 5×105cells/ml, 1×106cells/ml and 2×106cells/ml). By Triton method, Rmax and Rmin of K562 cells
were 1.21 and 0.20, respectively, and that of Hepa1-6 cells were 2.02 and 1. These results indicated that Rmax and Rmin
were not influenced by concentration gradient in a certain range of cell concentration, but they were different in various
types of cell lines.
Calcium signaling in UV-induced damage
Author(s):
Dan Sun;
Su-juan Zhang;
Yuan-yuan Li;
Ying Qu;
Zhao-Yu Ren
Show Abstract
Hepa1-6 cells were irradiated with UV and incubated for varying periods of time. [Ca2+]i (intracellular calcium
concentration) of UV-irradiated cell was measured by ratio fluorescence imaging system. The comet assay was used to
determine DNA damage. During the UVB-irradiation, [Ca2+]i had an ascending tendency from 0.88 J/m2 to 92.4J/m2.
Comet assay instant test indicated that when the irradiation dosage was above 0.88J/m2, DNA damage was observed.
Even after approximate 2 h of incubation, DNA damage was still not detected by 0.88J/m2 of UVB irradiation. During
UVA-irradiation, the elevation of [Ca2+]i was not dose-dependent in a range of 1200 J/m2-6000J/m2 and DNA damage
was not observed by comet assay. These results suggested that several intracellular UV receptors might induce [Ca2+]i
rising by absorption of the UV energy. Just [Ca2+]i rising can't induce DNA damage certainly, it is very likely that the
breakdown of calcium steady state induces DNA damage.u
Distribution and photobleaching of photosensitizer chlorophyll derivative (CPD) in SMCF7 cancer cells
Author(s):
Lie Lin;
Ping Chen D.D.S.;
Kun Zhang;
Yan Liu;
Guoqing Tang
Show Abstract
Photodynamic therapy (PDT) is a promising new treatment modality for several diseases, most notably cancer. In PDT,
light, O2, and photosensitizer are combined to produce a selective therapeutic effect. Chlorophyll derivative
photosensitizer(CPD) is the class of new photosensitizers for photodynamic therapy ( PDT) . And to date, little is known
about the interaction between the photosensitizer and the inner parts of tumor cell in PDT. A fluorescent microscopy and
imaging study on CPD was performed. To observe the dynamic process of how the photosensitizer (CPD) enters the
tumor cell and intracellular distribution of CPD in tumor cells, we used confocal laser scan microscopy(CLSM) under
one-photon excitation induced by a 488nm Ar+ laser. We also obtained the fluorescence photobleaching of CPD in cells
with varied intensity of excitation laser(488nm). By means of CLSM, we found most of the photosensitize CPD
distribute in on nuclear membrane but few in nuclear.
Using delayed chemiluminescence as a photodynamic therapy dose metric in vivo
Author(s):
Yanchun Wei;
Da Xing;
Qun Chen
Show Abstract
Photodynamic therapy (PDT) is an important method to treat tumor. It is known that singlet oxygen (1O2) is the main
factor mediating cytotoxicity in PDT. The effectiveness of a PDT treatment is directly linked to the 1O2 produced in the
target. So to control the dose of 1O2 is very important. Although the luminescence from 1O2 can be detected and is
suggested as an indicator for evaluating photodynamic therapy, the inherited disadvantages limit its potential for in vivo
applications. We have previously reported that chemiluminescence (CL) can be used to detect 1O2 production in PDT and
linked the signal to the cytotoxicity, but the irradiation of laser decrease the sensitivity of the detection in vivo. During
PDT the high sensitivity probe, Fluoresceinyl Cypridina Luciferin Analog (FCLA), is used to monitor 1O2. In order to
avoid the infection of irradiation light, the delayed CL of FCLA is used to indicate 1O2. After recording the delayed CL
during PDT and scoring the skin of mice after PDT, the statistic analysis was done. The data shows a remarkable
relationship between the score and the CL. the result suggests that the CL can be used as a dose metric in vivo in PDT.
Newly developed optical systems and their potential applications
Author(s):
Guoliang Huang;
Jiang Zhu;
Cheng Deng;
Shukuan Xu;
Zhonghua Dong;
Yang Yang;
Xiaoyong Yang;
Xianhua Wang;
Keith Mitchelson;
Jing Cheng
Show Abstract
Since microscope was invented in 17 century, optical instruments have continued to be an important tool for advanced
investigations in biology and medicine. The step by step development of optical technology has also preceded the
realization of macroscopic and microscopic biology, providing new advances that help better understanding of these
fields. Even today it is necessary to build new optical devices to foster the advancement of frontier biological research,
and for new applications in medical research. Here in this paper, we describe two new advanced optical systems for
biological detection, which are already used in a series of new instrument products, such as the confocal scanner, the
digital imaging scanning system.
Experimental research on LED light source used for ALA-PDT
Author(s):
Meixiang Liao;
Jianwen Xiong;
Hua Xiao
Show Abstract
A LED array is used as PDT light source in a photo-reaction chamber. The LED array is alterable in wavelength by
replacing different LEDs, stable in output power, adjustable in power value and spot size; the geometry of the LED array
is flat shape. Based on the experiment of ALA-PDT, we measured and analyzed the spectrum characteristics and output
power of some different purple LEDs, selected one as PDT light source whose emission peak is near the absorption peak
of the ALA. The experiment on HL60 tumor cells in vitro demonstrates our photo-reaction chamber has visible
photodynamic effect on ALA-PDT.
The survey of medical image 3D reconstruction
Author(s):
Liping Zheng;
Guangyao Li;
Jing Sha
Show Abstract
Medical image 3D reconstruction is an important research and application areas. A comprehensive survey is given in
four aspects: the general process of medical image 3D reconstruction, image fusion, image segmentation, and 3D
reconstruction algorithm.
Analysis of density features surrounding mammographic abnormalities
Author(s):
Jiang Luan;
Enmin Song;
Meng Bo;
Renchao Jin;
Xiangyang Xu
Show Abstract
In clinic, surrounding density of breast abnormalities is an important cue for radiologists to distinguish between benign
and malignant abnormalities on mammogram. It may also be an important feature to be used in computer-aided diagnosis
(CAD) system. The purpose of our work is to analyze the density distribution surrounding benign or malignant mass.
The cases used in this study are selected from the Digital Database for Screening Mammography (DDSM) provided by
the University of South Florida. For each case, the mass boundaries marked by experienced radiologists are used and 30
3-pixel-wide bands, one outside another, surrounding each mass are considered. A few density features including the
average gray level and the distribution skewness of the gray levels on every surrounding band were calculated. For every
feature in each corresponding band, average values were calculated for 10 benign cases and 10 malignant cases,
respectively. The preliminary analysis results show that the intensities surrounding benign masses tend to be higher than
those surrounding malignant masses. They also show that the standard deviation of intensities surrounding benign
masses tend to be larger than those surrounding malignant masses. Similar analysis was also carried out with mass
boundaries automatically identified by computer and the results corroborate the analysis with mass boundaries marked
by radiologists.
Medical image registration based on maximization of mutual information and particle swarm optimization
Author(s):
Qi Li;
Hongbing Ji
Show Abstract
In order to provide comprehensive information and improve the accuracy of clinical diagnoses and surgical therapies,
medical image fusion is becoming a new hot topic. As the basic and key issue medical image registration has very
important meaning. This paper offers a solution to medical image registration based on maximization of mutual
information (MI) and particle swarm optimization (PSO). First, the rigid transformation with translational and rotational
parameters is applied to the floating image. As an increasingly popular matching criterion for image registration, MI is
adopted in this method. Theoretically, the maximization of MI is obtained if the transformed image and the reference
image are geometrically aligned. Then an improved PSO algorithm is used to search the registration parameters. The
experimental results demonstrate the effectiveness of the proposed registration scheme.
3D reconstruction of coronary arteries from two x-ray angiograms based on anatomic model
Author(s):
Rong Tu;
Qin Li;
Haomiao Shui;
Jian Yang;
Yongtian Wang
Show Abstract
In this paper, we have developed a model-based approach to match two X-ray angiograms from different views. Under
the guidance of the prior knowledge of anatomic structure of human coronary vessels, this method can build a node
attribute table and assign unique anatomic labels to coronary arteries in X-ray angiograms automatically by the
father-son relationship of the nodes, which is essential in reconstruction of vessels.
Computer-aided measurements of cell electrorotation by image analysis techniques
Author(s):
Yang Yang;
Chengjun Huang;
Jiang Zhu;
Guoliang Huang;
Jing Cheng
Show Abstract
Electrorotation (ROT) is widely used for the investigation of the dielectric properties of biological cells. Traditionally the
tedious measurements of the rotational rates of the cells are handled manually. In this paper, a ROT chip detection
platform equipped with computer-aided measuring system is presented. The rotational motions of the cells are captured
by CCD camera and an algorithm is implemented to automatically estimate the rotational rates by analyzing the captured
image. The acquired data is verified by a comparison with manual stop-watch measurements. The experimental results
are accurate and robust against variations in illumination and cellular deformation within maximum 5% deviation from
the manual measurements. Thus the platform as a whole can be employed to detect changes in the cellular membrane
dielectric properties caused by external stimulation, or those occurring naturally.
A novel method to acquire 3D data from serial 2D images of a dental cast
Author(s):
Yaxing Yi;
Zhongke Li;
Qi Chen;
Jun Shao;
Xinshe Li;
Zhiqin Liu
Show Abstract
This paper introduced a newly developed method to acquire three-dimensional data from serial two-dimensional images
of a dental cast. The system consists of a computer and a set of data acquiring device. The data acquiring device is used
to take serial pictures of the a dental cast; an artificial neural network works to translate two-dimensional pictures to
three-dimensional data; then three-dimensional image can reconstruct by the computer. The three-dimensional data
acquiring of dental casts is the foundation of computer-aided diagnosis and treatment planning in orthodontics.
Ultrahigh resolution parallel Fourier domain optical coherence tomography using xenon flash lamp
Author(s):
Xuan Liu;
Ping Xue
Show Abstract
We present a parallel Fourier domain optical coherence tomography (FD-OCT) system using Xenon flash lamp. Parallel
configuration is implemented by one dimensional illumination and two dimensional detection with a CCD camera. The
imaging axial resolution is 2.6μm in air with maximum depth range of ~650μm. The dynamic range is ~70DB with
exposure time less than 1ms for a 1000*512 pixel image.
Ultrasound-modulated optical phenomena in scattering media driven by a pulsed transducer
Author(s):
Jiali Cai;
Lili Zhu;
Cuncheng Weng;
Hui Li
Show Abstract
In this presentation, several ultrasound-modulated optical phenomena in a tissue phantom were observed by a pulsed
ultrasound transducer. Some factors affected the modulated signal value were studied including the changing of the
experimental conditions such as the distance between the focused volume of ultrasound beam and the detector as well as
the frequency of ultrasound transducer. The experimental results and the analysis suggest that a compositive parameter
concerning the intensity of the modulated signal, namely the modulation depth which is a key parameter to measure the
scattering property even as a sensor to indicate the glucose concentration.
Numerical analysis on oxygen saturation measurement by dual-wavelength optical low-coherence interferometry
Author(s):
Ling Wang;
Zhihua Ding;
Lina Huang;
Martial Geiser
Show Abstract
Dual-wavelength optical low-coherent interferometry is proposed in this paper to measure the oxygen saturation in
human retinal blood vessel. Wavelength consideration is made from the standpoint of eye safety and system
sensitivity. Principle of oxygen saturation measurement based on dual-wavelength low-coherence interferometer is
thoroughly developed. Numerical simulation on interference signal versus oxygen saturation corresponding to the
oxygen sensitive wavelength and the isobestic wavelength is conducted.
Improvement of axial resolution in optical coherence tomography by optical pupil filter
Author(s):
Lin Zhou;
Zhihua Ding;
Jie Meng;
Zhenming Zhou
Show Abstract
Axial resolution is a key factor in optical coherence tomography (OCT). Biomedical applications will benefit from
improved resolution and quality that ultrahigh resolution OCT can provide. Existing approaches to improve axial
resolution of OCT mostly depend on new broadband light sources, which are always costly and inconvenient in
instrumentation. In this paper we adopt an alternative method to enhance the axial resolution of OCT by combining
coherence gate with optical superresolution. A three-zone phase pupil filter is designed and inserted into the sample
arm of OCT. The depth responses measured demonstrate that an improvement of more than 15% in axial resolution is
achieved in the proposed OCT system.
Optical coherence tomography based projected index computed tomography
Author(s):
Zhengming Zhou;
Zhihua Ding;
Yaliang Yang
Show Abstract
Projected index computed tomography (PICT) is an emerging noninvasive imaging technique that can provide
tomographic mapping of sample's refractive index. In this paper, we report a PICT system developed on the basis of a
fiber-optic OCT system. The tomographic mapping is reconstructed with convolution back projection algorithm using a
series of angular projection data collected by optical coherence tomography (OCT) at sequential orientations.
Measurement of refractive index distribution of a glass tube is carried out. The result shows that the developed system
has high resolution and sensitivity to discriminate tube boundaries. With index information involved, the reconstructed
PICT image is free of distortions, which are inherent artifacts of conventional OCT image.
A novel and fast method of detecting foreign body in biological tissue using microwave-induced thermoacoustic tomography
Author(s):
Liming Nie;
Da Xing;
Diwu Yang;
Lvming Zeng
Show Abstract
The customary methods for localizing the foreign body in human body present several disadvantages, radioscopy has
significant radiation exposure, MRI can not work with the metal, and also they are expensive and neither is portable.
Microwave-induced thermoacoustic imaging which shares similar mechanism with photoacoustic imaging can achieve
high ultrasound resolution and good microwave absorption contrast. Besides, microwave can reach deeply hidden sample
in biological tissue because of its long wavelength, hence, this new imaging modality can be potentially applied to detect
the foreign body hidden in human body. Our detecting methods were validated by imaging simulated foreign body
embedded in biological tissue at different depths, the unknown samples embedded deeply were discernible and the signal
to noise ratio was good. By employing the multi-element linear transducer array and phase-controlled focus algorithm, a
circular scan of thermoacoustic signals at 20 angles needs no more than 2 minutes. Our established thermoacoustic
imaging system has potential to supply a novel and fast method for surgical localization of an unknown foreign body.
A rapid gradient segmentation method for edge recognition of biomedical image
Author(s):
Guan-nan Chen;
Zhong-jian Teng;
Kun-tao Yang;
Rong Chen
Show Abstract
Image edge recognition is a crucial aspect of biomedical image processing. In this paper, a rapid gradient segmentation
method based on the depth-first traverse of images is presented. This method defines the data structure for the pixel
firstly, estimate and catch gradient from four pixels around the arbitrary point coming from an arbitrary pixel of image. If
the pixel satisfies the feature of edge, the edge perpendicular to the directions of gradient is processed by depth-first
traverse, the pixels are marked at the same time. It will withdraw when no pixels satisfy the feature in the directions, then
depth-first traverse from the next direction with gradient, mark the pixel as corner, and traverse the image completely.
The segmentation method has been applied to edge recognition of color biomedical image and other images. The
experimental results showed that edges and corners of biomedical image can be segmented obviously, and be easy to
identify.
Monitoring male canoeists' cardiac function by Doppler-echocardiography during heavy load exercise
Author(s):
Guodong Xu;
Huan Tan;
Zongzhen Mao
Show Abstract
This study is to evaluate cardiac systolic and diastolic function of Chinese male canoeists during heavy load exercise
training by Doppler echocardiography. Eighteen young male volunteer canoeists were tested, and trained five weeks.
Then the change of cardiac systolic and diastolic function of the tester was examined by the Doppler echocardiography
method.The results showed that there were no significant differences of LVEF and Δ%D, but the E/A ratio of elite
canoeists reduced (p<0.05) after the heavy load exercise training. Moreover, the ratio of E/A less than 1 was found in
two elite canoeists. The further research is required to understand the mechanism of the change. These results showed
that monitoring of diastolic function was more meaningful than monitoring of systolic function during the heavy load
exercise training, especially not neglected the cardiac function of elite canoeists.
An accelerated and convergent iterative algorithm in image reconstruction
Author(s):
Jianhua Yan;
Jun Yu
Show Abstract
Positron emission tomography (PET) is becoming increasingly important in the field of medicine and biology. The
maximum-likelihood expectation-maximization (ML-EM) algorithm is becoming more important than filtered
back-projection (FBP) algorithm which can incorporate various physical models into image reconstruction scheme.
However, ML-EM converges slowly. In this paper, we propose a new algorithm named AC-ML-EM (accelerated and
convergent maximum likelihood expectation maximization) by introducing gradually decreasing correction factor into
ML-EM. AC-ML-EM has a higher speed of convergence. Through the experiments of computer simulated phantom data
and real phantom data, AC-ML-EM is shown faster and better quantitatively than conventional ML-EM algorithm.
Study on the cerebrovascular reserve capacity by MR perfusion weighted imaging in SHR
Author(s):
Quan Zhou;
Yang Dong;
WenLi Chen D.D.S.;
Xueying Lin;
Da Xing;
Li Huang
Show Abstract
Cerebrovascular disease is one of the leading causes of death, and approximately 50% of survivors have a residual
neurologic deficit and greater than 25% require chronic care. Cerebrovascular reserve capacity (CVRC) describes how
far cerebral perfusion can increase from a baseline value after stimulation. High blood pressure is the most important
independent risk factor for stroke and other vascular diseases. The incidence of stroke in the hypertensive is six times
higher than in the patient with normal blood pressure. CVRC in the hypertensive was even lower than in control patients.
MR perfusion weighted imaging (MR PWI) with the well-established acetazolamide (ACZ) stimulation test has been
used for assessing brain function. The aim of this work is to assess the cerebrovascular reserve capacity by MR PWI with
"ACZ" tolerance test in spontaneous hypertensive rat (SHR) and to identify its value in evaluating the CVRC.
Experimental animal including 3 groups: Wistar-Kyoto rats (WKY) (12-week-old) as control group, SHR (12-week-old
and 20-week-old) as experimental group. MR PWI was performed respectively before and after acetazolamide
administrated orally in 3 groups on a clinical 1.5 Tesla GE Signa MR fx/i whole-body MR system. The ROI was chosen
in the bilateral frontal lobe to measure the value of rCBV, rCBF and MTT. The results showed that before ACZ-test,
there was statistic differences between the WKY and SHR(12-week-old), and between SHR(12-week-old) and
SHR(20-week-old) in the values of rCBV and rCBF (P>0.05), and after ACZ-test, there were statistic differences
between WKY and SHR (20-week-old), and between SHR(12-week-old) and SHR(20-week-old) in the rCBV value (P<0.05). It is concluded that the method of MRI PWI combined with the "ACZ stress test" can provide more qualitative
and half-quantitative information on the cerebral perfusion to evaluate the CVRC in SHR.
Imaging of gold nanoshell clearance in animal brains in vivo by improved-simultaneous-iterative-based photoacoustic tomography
Author(s):
Liangzhong Xiang;
Da Xing;
Huaimin Gu;
Diwu Yang;
Sihua Yang;
Lvming Zeng
Show Abstract
The high contrast and high resolution photoacoustic tomography was used to image the gold nanoshell clearance in rat
brain in vivo. With our current imaging system, the acquisition of photoacoustic signals is realized through a circular
scan of a single-element transducer. Therefore, the data acquisition is slow. In this case, an improved simultaneous
iterative reconstruction algorithm was developed to reduce the acquisition time by using limited data in the experiments.
This algorithm is based on the least square principle; it can be used to reconstruct high quality images from the limited
data containing much noise. Furthermore, it is always convergent. So it can improve the imaging quality comparison
with conventional filter back-projection algorithm (FBP) and algebraic reconstruction algorithm (ART). Here we
accurately mapped rat brain structures with gold nanoshell contrast agents. We also imaged the clearance of gold
nanoshell in the rat brain. It provides an accurate non-invasive monitoring method for fluid pathways in biological
tissues, which makes photoacoustic tomography as a powerful method for imaging pathologic tumor vessels, delineating
neovascularization, and studying global and regional hemodynamic activities in the brain.
Limited-view scanning microwave-induced thermoacoustic CT using a multi-element linear transducer array
Author(s):
Lvming Zeng;
Da Xing;
Diwu Yang;
Sihua Yang;
Liangzhong Xiang
Show Abstract
In this paper, we have developed a limited-view scanning microwave-induced thermoacoustic computed tomography
(CT) system based on the multi-element phase-controlled focus technique. A 320-element linear transducer array was
relatively rotated to capture thermoacoustic signals within limited detection views, which effectively eliminated the
problem that the focused ultrasonic transducer can but receive finite signal from boundaries of tissues which are nearly
perpendicular to the axis of the transducer. Using phase-controlled focus technique to collect thermoacoustic signals, the
data need not be averaged because of a high signal-to-noise ratio, resulting in a data acquisition time of less than 5 s in
each view. The collected limited-view data was utilized to reconstruct the geometrical details based on
limited-field-filtered back-projection algorithm. The system may provide a reliable approach to thermoacoustic imaging,
which can potentially be developed as a powerful diagnostic tool for early-stage breast caners.
Fast photoacoustic imaging with multi-element linear transducer array system
Author(s):
Diwu Yang;
Da Xing;
Huaimin Gu;
Lvming Zeng;
Liangzhong Xiang;
Sihua Yang
Show Abstract
Noninvasive monitoring of the microvascular network and detection the angiogenesis around tumors is one of the most
active areas in biomedical research. In this paper, we present a multi-element photoacoustic imaging system for fast
imaging the blood vessels. In this system, a Q-switched Nd: YAG pulse laser operated at 532nm with a 6 ns pulse width
is used to generate a photoacoustic signals; a 64-element linear transducer array with the central frequency of 7.5MHz is
used to measure the photoacoustic waves. The limited-field filtered back projection algorithm is used to reconstruct the
optical absorption distribution in tissue. The experiments of a phantom model and in vitro blood vessels were performed
with this system. A clear photoacoustic image of microvascular network was obtained with high resolution. The
experimental results demonstrate that our multi-element photoacoustic imaging system has the ability of imaging
microvascular network and may potentially be used to monitor the angiogenesis around tumors.
Femtosecond pulse dispersion in biotissue-like media: theory versus experiment
Author(s):
Ekaterina A. Sergeeva;
Alexey I. Korytin
Show Abstract
We report on experimental and theoretical study of a femtosecond NIR pulse distortion at its propagation in optically
turbid medium with highly anisotropic scattering. We have proposed a novel theoretical model of temporal structure of
a scattered pulse based on expansion of radiation intensity over orders of scattering. In parallel, we have performed
experiments on measuring profile of scattered 50-fs pulse passed a 5-mm slab of model medium with controlled
concentration of micron-sized spherical beads. Temporal structure was measured by the means of nonlinear optical
gating at noncollinear second harmonic generation. Comparison showed good agreement between experimental and
theoretical results and demonstrated validity of the developed theoretical model within wide range of scattering
parameters.
Noninvasive blood glucose measurement system based on three wavelengths in near-infrared region
Author(s):
Yaqin Chen;
Ge Bai;
Jun Xiao;
Long Wang;
Qingming Luo
Show Abstract
Near-infrared region of optical spectrum extends from 0.7 to 2.5μm and can be used for quantitative measurement of
organic functional groups, especially C-H, O-H, N-H and C=O. Analyzing sample concentration by near infrared
spectroscopy focuses on the design of the optical sensor and the spectral data processing. Noninvasive blood glucose
measurement methods using near-infrared spectroscopy usually apply a beam of light to irradiate the blood region of
human, and then extract the information of blood glucose from the spectrum. The key is to improve the signal to noise
ratio so that very low glucose absorption can be detected. In this paper, according to the absorption of glucose, a
noninvasive blood glucose measurement system based on three wavelengths in the near-infrared region was designed.
The system included several important parts such as the light source, the optical chopper, the detector and the lock-in
amplifier. The three wavelengths were respectively chosen at the signal wavelength 1610nm by glucose absorption peak
in the overtone band and the reference wavelengths 1200/1350nm to eliminate the interference effect. The optical probe
used an annular light bundle to greatly increase the intensity of incidence light and improve the signal-noise ratio. Two
group experiments of glucose aqueous solutions with different concentration interval in the normal human physiological
blood glucose range (0-500mg/dL) have been done to evaluate the predictive performance of the system. In these group
experiments, the partial least square algorithm was used to predict the glucose concentration. The preliminary results
showed when the interval was 100mg/dL, the correlation coefficient (R) was 0.998 and the root mean square error of
prediction (RMSEP) was 17.08mg/dL; and when the interval was 20mg/dL, the values of R and RMSEP were 0.959 and
23.22mg/dL, respectively.
Quantifying the properties of high scattering media with Mueller matrix
Author(s):
Yong Deng;
Qiang Lu;
Qingming Luo
Show Abstract
We have developed a new third-order approximation model of Mueller matrix for spatial characterization of the
polarization effects in backscattering from highly scattering media. Using the Stokes-Mueller formalism and scattering
amplitudes calculated with Mie theory, we are able to numerically determined matrix elements. Specific features of the
2D Mueller matrix components corresponding to light backscattered from polystyrene micosphere suspensions are
characterized and compared with the experimental data for different size of scatterers, the scattering coefficient and the
anisotropy factor g. The results show good agreement in both azimuthal and radial direction.
Polarization videoreflectometry of multiple scattering anisotropic media in application to fibrous tissue diagnostics
Author(s):
O. V. Ushakova;
L. V. Kuznetsova;
D. A. Zimnyakov
Show Abstract
Diffuse reflectance of polarized light is studied in application to characterization of multiple scattering anisotropic
media (such as, e.g., the fibrous tissues) with the use of focused probe laser beam. The theoretical model for description
of the transport properties (the values of transport scattering coefficients and effective refractive index for different
polarization states of probe light) of closely packed systems of partially disordered dielectric cylinders is considered on
the base of coherent potential approximation. The influence of structural and optical characteristics of fibrous systems
(such as the volume fraction of cylindrical scatters, their average diameter, the degree of disorder, refractive indices of
scatters and surrounding medium) on diagnostical parameters determined with the polarization videoreflectometry can
be analyzed in the framework of the considered theoretical model. The obtained theoretical results satisfactorily agree
with the experimental data on polarization videoreflectometry and spectral-polarization measurements in the
transmittance mode of in-vitro samples of demineralized bone, muscular tissue and phantom samples (partially oriented
polymer films).
Polarization optical reflectometry: the technique for puncture diagnosis
Author(s):
Alex V. Mjakov;
Pavel D. Agrba;
Natalia M. Shakhova M.D.;
Vladislav A. Kamensky
Show Abstract
We propose to realize an endoscopic all-fiber clinical device for polarized reflectance spectroscopy based on
polarization-maintaining (PM) fiber. Results of testing the above device in model media and the first data of clinical
investigations are presented.
Investigations in vivo were carried out on the uterine cervix with benign and malignant alterations. 7 female patients
were examined. POR technique confirm a possibility of differentiating neoplastic changes by the depolarization ratio.
Methods of cross polarization OCT
Author(s):
Valentin M. Gelikonov
Show Abstract
We consider methods of cross polarization optical coherence tomography (OCT) using the polarization-maintaining
(PM) and the single-mode (SM) fibers that can give additional information about biotissue. A cross-polarized optical
coherence tomography (CP OCT) system based on Michelson interferometer with PM fiber uses natural orthogonally
polarized waves to form two channels receiving scattered light in initial (linear) polarization and in the orthogonal
polarization. A novel cross-polarized optical coherence tomography (CP OCT) system is developed, which is based on
standard isotropic single-mode fiber. We exploit the property of an arbitrary pair of orthogonal waves propagating in a
single-mode fiber to maintain their orthogonality in the absence of anisotropy losses, regardless of induced phase
anisotropy. The well-known isotropic fiber based OCT scheme that commonly comprises an optical probe with a Fizeau
interferometer and a compensating Michelson interferometer with Faraday mirrors is modified. We introduce an
additional optical element to form the initial radiation into two mutually time-delayed and coherent waves that have
strictly orthogonal polarizations.
Glucose sensing in biotissue phantom by spatial resolved reflectometry: Monte Carlo simulations
Author(s):
Mikhail Yu. Kirillin;
Alexander V. Bykov;
Alexander V. Priezzhev;
Risto Myllyla
Show Abstract
The possibility of spatial resolved reflectometry (SRR) application at wavelength of 820 nm for the detection of
changes in optical properties of multilayer scattering medium was considered. The considered changes
correspond to changes induced by glucose level variations in model biotissue. The model signals from a 3-layer
biotissue phantom mimicking two skin layers and a blood layer between them were obtained by implementing
Monte Carlo technique. It was supposed that changes in the glucose level induce changes in the blood layer and
the deeper skin layer. In order to analyze the trajectories of the photons contributing to the signal, the scattering
maps were obtained. Relative changes of the signal induced by the glucose level variations was analyzed for
different source-detector separations. It was shown that the maximal relative change of the signal of about 7%
corresponding to the glucose concentration change from 0 to 500 mg/dl takes place for source-detector
separations in the range from 0.3 to 0.5 mm depending on the model parameters.
Coherent backscattering diagnostics of tissue-like media and tissues
Author(s):
Liana V. Kuznetsova;
Dmitry A. Zimnyakov
Show Abstract
The transport properties of highly scattering media including biotissues with expressed fibrillar structure are studied by
measuring coherent backscattering. Fitting of the experimental data with the coated coherent potential approximation led
to evaluation of the transport parameters without a-priori knowledge of the optical properties of scattering particles for
strongly scattering dense media. The peculiarities of light diffusion in multiple scattering media characterized by
macroscopic anisotropy of scattering properties (such as, the collagen-containing biological tissue with partially oriented
fibrillar structure) are introduced. The experimentally obtained ratio of the reduced scattering coefficients in the
directions of parallel and perpendicular to the fibers is equal to 0.37 which is in a good agreement with the same value
obtained with laser videoreflectometry method.
Enhancement of spontaneous burst activity of hippocampal neuronal networks with low frequency close-loop stimulation
Author(s):
Yanling Li;
Wei Zhou;
Shaoqun Zeng;
Xiangning Li;
Man Liu;
Qingming Luo
Show Abstract
In this paper, we study the modulation of low frequency closed-loop electric stimulation on spontaneous activity in cultured hippocampal neuronal networks. First, we plated monolayer cultures of hippocampal neurons from rat embryos (E18) on multi-electrode arrays and the experiments were performed in the networks from the second week to the sixth week continuously. During the experiments, we detected the spontaneous spikes of the networks firstly, and then stimulated the networks at low frequency (0.2 Hz or 1 Hz) stimulation respectively until a desired response was observed 20-80msec after a stimulus. The protocol was closed-loop. After that, we detected the spontaneous spikes of the networks. It is observed that the spontaneous activity in the developing networks is developing, which is oscillatory and periodic. Low frequency (0.2 Hz or 1 Hz) stimulation enhanced the spontaneous synchronous burst activity of the developing networks. These results implicated that activity-dependent mechanism in the modulation of plasticity of synaptic transmission in the cultured neuronal networks. Closed-loop stimulation will give a better view on the functional significance of networks activities. Besides, close-loop stimulation could set up the stimulus-reward system in the neuronal networks, which is of great benefit to the plasticity of synaptic transmission in the cultured neuronal networks.
Synchronies in cultured neuronal network
Author(s):
Yunsheng Lin;
Lin Chen;
Shaoqun Zeng;
Qingming Luo
Show Abstract
The neuronal network cultured in virto used as an important tool for study have been realized by more and more
researchers owing to its non-invasive nature. But till now, there isn't a parameter that can conveniently describes the
changing states of neuronal network from the whole. In this paper, the synchrony calculation acted as the reactive results
of the neuronal network to electrical stimulation (used for learning training) or bicuculine is analyzed and the variety of
the synchrony of the network is tried as an important value to depict the diversification of the neuronal network. These
experimental results processed in this way are given out in the end of this paper.
A biomedical information system for neuroimaging and brain function
Author(s):
Jun You;
Jie Zhang;
Qingming Luo
Show Abstract
In order to solve the database interoperability and neuroscientific information integration, we have built an
internet-accessible Biomedical Information System (BMIS) for neuroimaging and brain function research. BMIS is a
multi-purpose academic periodical full-text literature platform; it safeguards the literature involving Neuroscience,
Biomedical Photonics, Medical Imaging, Bioinformatics and so on, and can carry on the input, retrieval and maintenance
of the literature data. Based on the cluster system of TS10000 and new data processing technologies, the establishment of
this integrated, individualized and extensible system will provide the massive data set needed for knowledge discovery
and will serve as a foundation for future hypothesis-driven experiments, which begin with a special problem of
substantial scientific interest about neuroimaging and brain function.
Spontaneous generation and disappearance of burst firing in cultured neuronal network
Author(s):
Man Liu;
Wei Zhou;
Xiangning Li;
Qingming Luo
Show Abstract
Burst as a unit of information coding is widely investigated in the developing central nervous system. However the
mechanism underling the bursts generate and disappear is unclear at present. Neurons cultured on the multi-electrode
arrays, are spontaneously active, and show complex pattern with random spikes and bursts firing. With long-term
recording, the course of bursts generation and disappearance was detected. The results showed that the firing pattern
could transform from random spikes to bursts firing. In the beginning, the random spikes rate decreased, accompanied
with bursts occurred once in a while. It appeared both single spikes and bursts at the same time. After that, the random
spikes disappeared. Spontaneous activity displayed a regular occurrence of bursts with shorter interspike interval. During
such bursts the firing rate at the active sites was increased dramatically. After several seconds, firing rate decreased,
interburst interval extended, accompanied with the occurrence of random spikes, opposite to the beginning. At last,
bursts disappeared and the networks just fired in random spikes. The observation showed that the complex
electrophysiological activities of the cultured neuronal networks could implicate the spontaneous generation of burst
firing. Understanding how bursts generate and disappear might be significant for deeply investigating the function and
mechanism of bursts information coding.
Frequency domain fluorescence diffuse tomography of small animals
Author(s):
Anna G. Orlova;
Ilya V. Turchin;
Vladislav A. Kamensky;
Vladimir I. Plehanov;
Irina V. Balalaeva;
Ekaterina A. Sergeeva;
Marina V. Shirmanova;
Michail S. Kleshnin
Show Abstract
Fluorescent compounds for selective cancer cell marking are used for development of novel medical diagnostic methods,
investigation of the influence of external factors on tumor growth, regress and metastasis. Only special tools for turbid
media imaging, such as optical diffusion tomography permit noninvasive monitoring of fluorescent-labeled tumor
alterations deep in animal tissue. In this work, the results of preliminary experiments utilizing frequency-domain
fluorescent diffusion tomography (FD FDT) experimental setup in small animal are presented. Low-frequency modulated
light (1 kHz) from Nd:YAG laser with second harmonic generation at the wavelength of 532 nm was used in the setup.
The transilluminative planar configuration was used in the setup. A series of model experiments has been conducted and
show good agreement between theoretical and experimental fluorescence intensity. Models of deep tumors were created
by two methods: (1) glass capsules containing fluorophore solution were inserted into esophagus of small animals to
simulate marked tumors; (2) a suspension of transfected HE&Kgr;293-Turbo-RFP cells was subcutaneously injected to small
animal. The conducted experiments have shown that FD FDT allows one to detect the presence of labeled tumor cells in
small animals, to determine the volume of an experimental tumor, to perform 3D tumor reconstruction, as well as to
conduct monitoring investigations. The obtained results demonstrate the potential capability of the FD FDT method for
noninvasive whole-body imaging in cancer studies, diagnostics and therapy.
Restoration of fluorescence images from two-photon microscopy using modified nonlinear anisotropic diffusion filter
Author(s):
Hongmin Zhang;
Qingming Luo;
Shaoqun Zeng
Show Abstract
Two-photon laser scanning fluorescence microscopy is becoming a powerful tool in study of neuron functional imaging
in vivo for its inherent deeper penetration, less photo-damage. Now, with the two-photon fluorescence images of brain
tissue, we can reconstruct three-dimensional neuronal morphologies easily. However, the images usually are obscured by
a lot of noise, in particular in deep tissue with strong excitation laser power. Therefore, good image restoration technique
that could remove the noise while preserve neuronal structure is crucial for the results of subsequent image segmentation
and neuron reconstruction. Here, we propose a modified nonlinear anisotropic diffusion filter which incorporates both
gradient and gray-level variance of raw data, to remove the noise, rather than merely considers gradient as the classical
Perona-Malik nonlinear anisotropic diffusion model. Experimental results have shown that the proposed scheme can
remove noisy speckles effectively while maintain the shape of neuronal morphologies in two-photon fluorescence
images without conflict.
Modulation of temperature on optical properties of rat skin in vivo
Author(s):
Qing Ouyang;
Dan Zhu;
Qihuan Luo;
Hui Gong;
Qingming Luo
Show Abstract
Local optical properties of tissue measurement system combined with a temperature control setup were used to
investigate temperature-induced changes in optical properties of rat skin in vivo. The temperature of skin was maintained
at 32°C, 35°C, 38°C and 41°C for more ten minutes, respectively. And the system composed a single wavelength
(1310nm), multi-arrays optical probe with the separations of source-detector less than 1.25mm, was introduced to
measure the reflectance of skin. The results showed that the reflectance at higher temperature was less than that at lower
temperature. Further more, the optical properties were calculated. The higher temperature, the more both reduced
scattering coefficient and absorption coefficient decreased. It means that temperature rise will induces a decrease in
attenuation coefficient, and increase the penetrability of light. Research on temperature effect of skin may be helpful to
optical clearing technique.
Assessment of diffusion coefficient of glycerol into the skin ex vivo
Author(s):
Anna A. Gavrilova;
Alexander B. Pravdin;
Valery V. Tuchin;
Gregory B. Altshuler;
Ilya V. Yaroslavsky
Show Abstract
In present study we have considered diffusion of immersion agent into the skin through thermally pretreated stratum
corneum solving the corresponding diffusion problem. Algorithm of refractive index of interstitial liquid and diffusion
coefficient of immersion agent into biotissue estimations at a creation of lattice-like pattern of localized thermal damage
islets in the stratum corneum, was develop. Theoretical model which sufficiently describes the influence of immersion
agents on skin optical properties was presented. The diffusion coefficient of glycerol into pig skin ex vivo at creating a
lattice of islets of damage in the stratum corneum is 0.84±0.08 μm2/s.
Optimal sizes of gold nanoparticles for laser treatment of tumors
Author(s):
Alexey P. Popov;
Alexander V. Priezzhev;
Risto Myllylä
Show Abstract
In the present paper, the problem of laser treatment of tumors by means of gold nanoparticles is discussed. One of the
mechanisms of cancerous cells destruction is formation of small bubbles on cell membranes and inside cells around gold
nanoparticles induced by laser pulse absorption by the particles. It is shown by Mie theory calculations that the optimal
spectral region for such tumor treatment is within 400 - 550 nm with the corresponding nanoparticles sizes to be 30 - 40
nm. The appropriate durations of laser pulses for such kind of laser therapy are under 1 ns in this spectral region.
Gold nanoshells as solid-phase dot assay labels
Author(s):
Boris N. Khlebtsov;
Lev A. Dykman;
Vadimir A. Bogatyrev;
Nikolai G. Khlebtsov
Show Abstract
We report on the first application of silica-gold nanoshells to a solid-phase dot immunoassay. The assay principle is based
on staining of a drop (1μL ) analyte on a nitrocellulose membrane strip by using silica/gold nanoshells conjugated with
biospecific probing molecules. Experimental example is human IgG (hIgG, target molecules) and protein A (probing
molecules). For usual 15-nm colloidal gold conjugates, the minimal detectable amount of hIgG is about 4ng. By contrast,
for nanoshell conjugates (silica core diameter of 70 nm and gold outer diameter of 100 nm) we have found significant
increase in detection sensitivity and the minimal detectable amount of hIgG is about 0.5 ng.
Laser diffraction analysis of shear deformability of human and rat erythrocytes in norm and ischemia
Author(s):
A. E. Lugovtsov;
A. V. Priezzhev;
S. Yu. Nikitin;
V. B. Koshelev
Show Abstract
Ischemic diseases of people and animals are accompanied with deterioration of microrheologic properties of their
blood, in particular, with impairing red blood cells (RBC) deformability. In this work, the analysis of human and rat
RBC deformability in norm and ischemia was performed by means of the laser diffractometry - a modern technique
allowing for measuring the flexibility of RBC, which determines the blood flow parameters in vessels. Human RBC
were obtained from the blood of healthy individuals and from patients suffering from ischemic diseases. Human RBC
deformability from both groups of individuals was measured. Rat RBC were obtained from a control group of animals
and from a group with experimentally induced ischemia (EII). This animal model is frequently used for studying the
response of an organism to ischemia. The effect of Semax, a medication that is frequently used for therapeutic
treatments of human brain diseases in clinical practice, on RBC deformability was studied with its application in vitro
and in vivo.
It is shown that in human ischemic patients, the deformability of RBC was lower than that from healthy individuals.
Both in vivo and in vitro applied semax positively influences the impaired deformability properties of RBC of ischemic rats.
Dynamic imaging of cerebral blood flow in rat reperfused mini-stroke model using laser speckle temporal contrast analysis
Author(s):
Zhen Wang;
Weihua Luo;
Pengcheng Li;
Shaoqun Zeng;
Qingming Luo
Show Abstract
Laser speckle temporal contrast analysis (LSTCA) was used to image the cerebral blood flow (CBF) of ischemic area in
reperfused mini-stroke model in rats. Focal cortical ischemia in male Sprague-Dawley rats (n=20) was induced by
deliberate ligation of multiple branches of the middle cerebral artery (MCA) together with a nylon ring and the dura.
LSTCA was used to monitor the spatio-temporal characteristics of cerebral blood flow dynamics in the rat
somatosensory cortex in the ischemic and reperfused stages. The infarction volume was measured by 2, 3, 5-
triphenyltetrazolium chloride (TTC) staining 24 hours after reperfusion. The distribution of changes in cerebral blood
flow which outlined by the laser speckle imaging represented the relative CBF gradient (21.98±1.96%, 67.2±1.67 %,
107.24±4.71 % of the baseline) from ischemic core, penumbra zone to normal tissue immediately after cortical
ischemia, in which a central ischemic core had little or no perfusion surrounded by a penumbral region with reduced
perfusion, in addition, we had shown the existence of a surrounding region of hyperemic tissue; Thereafter a postrecanalization
hyperperfusion occurred in the same infarct core since 24 hours after reperfusion (242.62±18.52% of the
baseline). Histology of the ischemic regions at 24 hours after reperfusion revealed small focal infarcts that were
typically 3~4 mm in diameter, approximately equal to the nylon ring in size and position and essentially accordant with
the spatial distribution of the ischemic cortex with below 30% residual CBF of the pre-ischemic baseline. It was
demonstrated that this technique of LSTCA was easy to implement and availably used to image the spatial and temporal
evolution of CBF changes with high resolution in rat reperfused mini-stroke model.
Temporal dynamics of blood microcirculation in oral cavity mucous membrane, caused by low-intensity laser irradiation at the wavelength 630 nm
Author(s):
Natalia Kharish;
Elena Safonkina;
Mikhail Naumov;
Sergey Ulyanov;
Natalia Bulkina;
Larisa Ostrovskaya;
Yulia Osipova;
Katia Omelchenko
Show Abstract
Influence of laser irradiation on the statement of blood microcirculation in mucous membrane of human oral cavity has
been investigated. Speckle methods and Doppler diagnostics have been used for investigation of temporal fluctuation of
velocity of blood microcirculation. Pulse waves (low temporal changes of hemodynamics) have been studied by
methods of laser photoplethysmography. Influence of coherent light (at the wavelength 630 nm) on the intensity of
microcirculation in the capillary net of mucous membrane has been demonstrated directly during the short-time session
of laser therapy. It is shown that during the session of laser therapy it is expedient to use first-order frequency-weighted
spectral moments of Doppler signal for evaluation of the effects of laser irradiation on the intensity of microcirculation
in human oral cavity mucous membrane. Preliminary investigations, involving the objective methods of monitoring the
statement of microcirculation, show that coherent light can cause the slight enhancement of intensity of
microcirculation during the short sessions of laser therapy. Effect of lasers on the blood saturations is not reliably
observed.
Low intensity laser treatment of nerve injuries
Author(s):
Xiao-Guang Liu;
Timon Cheng-Yi Liu;
Qing-Ming Luo
Show Abstract
The neural regeneration and functional recovery after nerve injuries has long been an important field in neuroscience.
Low intensity laser (LIL) irradiation is a novel and useful tool for the treatment of many injuries and disorders. The aim
of this study was to assess the role of LIL irradiation in the treatment of peripheral and central nerve injuries. Some
animal experiments and clinical investigations have shown beneficial effects of LIL irradiation on neural tissues, but its
therapeutic value and efficacy are controversial. Reviewing the data of experimental and clinical studies by using the
biological information model of photobiomodulation, we conclude that LIL irradiation in specific parameters can
promote the regeneration of injured peripheral and central nerves and LIL therapy is a safe and valuable treatment for
superficial peripheral nerve injuries and spinal cord injury. The biological effects of LIL treatment depend largely on
laser wavelength, power and dose per site and effective irradiation doses are location-specific.
Photoinactivation of bacteria of P. Aeruginosa: role of light coherence
Author(s):
Onega V. Ulianova;
Sibo Zhou;
Zhihong Zhang;
Sergey S. Ulyanov;
Qingming Luo
Show Abstract
Influence of laser irradiation and low-coherent speckles on the colonies grows of Pseudomonas Aeruginosa is studied. It
has been demonstrated that effects of light on the inhibition or re-activation of cells are connected with speckle
dynamics. Role of temporal coherence of light at photoinactivation of bacteria is studied. The regimes of cell
suspension perfusion with purpose of devitalization of bacteria are found on the base of experimental investigations.
Mathematical model of interaction of low-coherent laser radiation with bacteria suspension has been developed.
Parameters of mathematical model have been identified on the base of experimental researches. Computer simulations
of the processes of laser-cells interaction have been carried out.