The state of the art of in-vivo and in-vitro penetration measurements of topically applied substances is described. Only optical techniques represent online measuring methods based on the absorption or scattering properties of the topically applied substances. Laser scanning microscopy (LSM) has become a promising method for investigations in dermatology and skin physiology, after it was possible to analyze the skin surface on any body side in-vivo. In the present paper the application of a dermatological laser scanning microscope for penetration and distribution measurements of topically applied substances is described. The intercellular and follicular penetration pathways were studied.

We propose a theoretical modeling of a turbid medium images formed by two-photon fluorescent microscopy technique. On the basis of this model, general properties of the calculated images, such as the registered fluorescence intensity dependence on the focusing depth and the influence of the scattering in the medium, have been studied. A comparison of image properties for single-photon and two-photon microscopy is given.

One of important stages of the substrate bond breaking in the active site (AS) of α-chymotrypsin (ACT) is considered. Three tasks are solved by methods of quantum mechanics and stochastic molecular dynamics: the loosening of peptide bond of a substrate attacked by O^- ion of Ser195 of catalytic group; the opportunity of increase of a peptide bond (PB) breaking probability; the increase of this probability related to nonlinear interacting modes (or Fermi resonance (FR)) of oscillations of group N-H in PB. It is shown also that the splitting of vibrational levels Amide A and Amide B in a spectrum of an amide group pays off due to FR.

F₁-ATPase is one of the most important enzymes of membrane bioenergetics. F₁-ATPase is the constituent complex that provides the ATP formation from ADP and inorganic phosphate (P_i) at the expense of energy of electrochemical gradient of hydrogen ions generated across the energy transducing mitochondrial, chloroplast or bacterial membrane. F₁-ATPase is a reversible molecular machine that can work as a proton pump due to energy released in the course of ATP hydrolysis (ATPase reaction). The unusual feature of this enzyme is that it operates as a rotary molecular motor. Recently, using the fluorescence microscopy method for the real time visualization of molecular mobility of individual molecules, it was demonstrated directly that the ATP hydrolysis by F₁-ATPase is accompanied by unidirectional rotations of mobile subunits (rotor) of F₁F₀-ATP synthase. In this work, we calculated the contribution of electrostatic interactions between charged groups of a substrate (MgATP), products molecules (MgADP and P_i), and charged amino acid residuals of ATPase molecule to the energy changes associated with the substrate binding and their chemical transformations in the catalytic centers located at the interface of α and β subunits of the enzyme (oligomer complex α₃β₃γ of bovine mitochondria ATPase). A catalytic cycle of ATP hydrolysis considered in our work includes conformational changes of α and β subunits caused by unidirectional rotations of an eccentric γ subunit. The knowledge of energy characteristics and force field in catalytic center of an enzyme in different conformational states may be important for further simulation dynamic properties of ATP synthase complex.

Refraction index and scattering properties of biological liquid and tissue are changing in low level laser field due to alteration of their structure state. The field model of low-level optical radiation effect on a human organism is presented. In vivo and in vitro experimental results confirm this approach.

During cystoscopy procedure, fluorescence diagnostics induced by 5-ALA improves visual detection of the bladder cancer. Macroscopic ALA-fluorescence allows visualizing of small flat tumors, carcinoma in situ, true neoplasm margins and dysplasias of the bladder. Following ALA instillation, cystoscopy has been performed under both standard and blue light illumination. Totally, 153 biopsies have been carried out at 53 patients with suspicion of bladder cancer. The results were compared to ALA-fluorescence data. In 13% of the patients, bladder cancer and dysplasia were found out in addition, due to red fluorescence. The sensitivity and specificity of ALA-fluorescence technique aggregated 96% and 52% respectively. The sensitivity and specificity of 5-ALA-fluorescent detection exceeded standard endoscopy under white light on 20%. The new method does not exclude a false positive and a false negative fluorescent luminescence. The ALA-based fluorescence detection system enhances the diagnosis of malignant/dysplastic bladder lesions significantly.

The method of fluorescent diagnostics (FD) of tumors is a promising tool that may allow to increase sensitivity of tumor detection especially at initial stages. One of the most promising photosensitizers today is 5-aminolevulinic acid (5-ALA) that, actually, is not photosensitizer itself but precursor of protoporphyrin IX (PpIX). This paper deals with cancer diagnostics in gynecology by means of ALA-induced Pp IX laser-fluorescence spectroscopy. The tissue fluorescence spectra in vivo were studied in patients with various pathologies of ovaries, uterine and vulva after 5-aminolevulinic acid administration. It was shown that different pathologies varies in accumulation of Pp IX. Coefficient of fluorescence k_f for normal tissue is not high, but exceptions are endometrium and mucous membrane of uterine tubes. Benign tumors of uterus and ovary have low values of k_f, but polyps of endometrium exhibit high k_f. Optical express-biopsy is important for diagnosis of ovarian cancer and micrometastatic spread. Coefficients of diagnostic contrast were determined for cancer of endometrium, cervical cancer, vulvar cancer.

The results have been obtained by flow cytometry showed the significant raise of fluorescence intensity of Yersinia pestis EV cells binding FITC-labelled plague polyclonal immunoglobins after 24 h cultivation in Hottinger broth pH 7.2 at 37 °C in the presence of increasing concentration serotonin (5-Hydroxytryptamine). The presence of serotonin (5-HT) in nutrient broth at concentration of 10^-5 M, 10^-8 M could modulate DNA content in 37 °C growing population of plague microbe. The effect of this action depended of 5-HT concentration.

The method of dynamical spectroscopy the change in sizes of aggregates of bile vesicules caused by different nucleating factors has been investigated. It is shown that the bile vesicule sizes at chronic cholecystites vary from 90-200 nm. In so doing, the presence of a large fraction of bile vesicules characterized, as shown in the paper, by a higher concentration of cholesterol can serve as a criterion for cholestitis acuteness and litogenesis intensity.

A multiphysics approach, combining acoustics, optics, and mechanics can be used to detect regions of skin with distinct mechanical behavior that may indicate a pathology, such as a cancerous skin lesion. Herein, an acousto - optical approach to evaluating the viscoelastic behavior of superficial skin layers will be presented. The method relies upon inducing low frequency guided surface waves in the skin and detecting these waves by monitoring the shift in the backscattered laser speckle pattern created by illuminating a small region of the skin with coherent light. Artificial lesions in the form of chemical cross-linking and chemical softening were induced in superficial porcine skin layers and detected based upon variations in local mechanical behavior. The lesions affect not only the time-of-flight of the guided surface waves, but also change the relative phase of the acoustic waves as determined optically. The method may be applicable in the study and diagnosis of superficial skin lesions.

Optical coherence tomography (OCT) is one of the most promising recently developed methods for non-invasive in vivo characterization of biological highly scattering tissues. However, one of the drawbacks of the pure OCT imaging is that it is not sensitive to changes in metabolism. This may impact derived information and consecutive diagnostics, because pathological changes of tissue structure are accompanied with changes in metabolic activity or functional state in these areas even if there is not yet strongly evident structural change. Therefore, it is desirable to combine early detection of tissue malformations by OCT with other techniques, capable to detect and evaluate their functional state. One of suitable candidates for such non-invasive optical functional imaging is detection of laser induced autofluorescence, which could provide information about rate of biological and chemical processes in living cells. As an example, the cells in proliferative state (with increased metabolic activity or during mitosis) show more intensive NIR fluorescence than the cells that are not proliferative, because of increased concentration of free porphyrins. In presented study we used OCT and laser induced NIR autofluorescence imaging for detection and evaluation of changes in areas of naevus and injuries in group of volunteers. The fusion of information on structural and functional state of biotissues provided by the two mentioned complementary methods may enhance the diagnostics power of their prospective clinical use. Firstly the fluorescence of area of naevus and injuries, excited by 630 nm was taken by CCD camera and then was naevus scanned by OCT. The findings of both methods were compared and correlated. In the case of naevus the obtained results were reviewed with histological treatment of the same area.

Pressure waves can be generated in biological tissues by pulsed lasers which deposit optical energy in absorbing structures such as blood vessels. Arrays of acoustic detectors on a tissue surface can sense the arrival of such waves. Analysis of the time-resolved signals can be used to reconstruct the 3-D distribution of the absorbing structures. In this report, a computer simulation was developed (see code listed in Appendix) to predict the time-resolved spatial distribution of pressure in a tissue in response to a pulse laser beam. In particular, the temporal history of pressure generated in a sphere of uniform energy deposition was calculated to illustrate the calibration of the computation. The temporal histories of pressures generated by a flat-field beam and a Gaussian-profile beam are also presented. The results show that the sharp edge of the flat-field beam yields tensile pressure wave and the pressure pattern is significantly different than the pressures produced by the smoother Gaussia-profile beam. The computer simulation is a very simple computation that is a valuable tool for predicting expected experimental results, and may be used in a reconstruction algorithm. This paper can be viewed at http://optics.sgu.ru/SFM/2002/internet/Jacques/index.htm.

Non-invasive blood glucose sensing often employs contact measurement, that is, the optical probe directly contacts the skin to reduce specular reflection. The contact pressure and the variation of skin temperature therefore contribute much to interference incurred by the internal structure and composition change of the detecting part. In this paper, we are going to discuss the influence of contact pressure between fiberoptic probe and skin as well as heat transfer on spectral measurement. A through investigation is made on approaches to eliminate these factors for both contact and non-contact measurement.

The paper briefly reviews the methodology of the symbolic nucleic sequence conversion into genomic signals and presents large scale and global features of the resulting genomic signals. Whole chromosomes or whole genomes are converted into complex signals and phase analysis is performed. The phase, cumulated phase and unwrapped phase of genomic signals are studied as tools for revealing important features of to the first and second order statistics of nucleotide distribution along DNA strands. It is shown that the unwrapped phase displays an almost linear variation along whole chromosomes. The property holds for all the investigated genomes, being shared by both prokaryotes and eukaryotes, while the magnitude and sign of the unwrapped phase slope is specific for each taxon and chromosome. The comparison between the behavior of the cumulated phase and of the unwrapped phase across the putative origins and termini of the replichores suggests a model of the 'patchy' structure of the chromosomes.

An overview on some advanced techniques of fluorescence spectroscopy and fluorescence microscopy is given. These techniques include time-resolved fluorescence spectroscopy, energy transfer spectroscopy (FRET), total internal reflection fluorescence microscopy (TIRFM) and fluorescence lifetime imaging (FLIM). The principle of these methods is explained, and numerous applications are described.

A diagnostic method is described to detect differences between diseased and normal tissue from bladder carcinoma by FTIR-microspectroscopy and fiber-optics methods. Regions of interest on 10 μm thin tissue sections were mapped using an IR-microscope in transmission mode. Afterwards the specimens were analyzed using standard pathological techniques. Quadratic discriminant as well as correlation analysis was applied for data analysis. IR optical fibers, not only allowed measurements to be made in the attenuated total reflectance (ATR)-mode but also absorption measurements to be carried out at a remote location. The IR-sensor is in contact with the sample which shows characteristic absorption lines. This method can be used to determine the absorption of a sample in a non-destructive manner. In this paper we report our efforts to develop a fiber-optic infrared sensor to differentiate between malignant and healthy tissue in vivo. Silver halide fibers and a special sensor tip were used for the ATR measurements on human tissue specimens. The results indicate that IR-spectrometry will be a useful tool for bio-diagnostics.

We studied the temperature-controlled localized reflectance of the dorsal arm of diabetic and non-diabetic subjects. The thermo-optical response of human skin at small source-detector distances is related to the diabetic status of the subject. It was possible to segregate diabetic from non-diabetic data based on the values of μa, μs^' and δ; and the change in their values (Δμa, Δμs^', and Δδ) as a function of temperature. The segregation into diabetic and non-diabetic based on the thermal response of μa, μs^' is consistent with cross-linking of vascular and tissue proteins by excess glucose during frequent hyperglycemic episodes.

Much attention has been devoted to the enzymatic production of nitric oxide (NO) by the endothelial layer lining blood vessel walls, which regulates among other things local vasodilatation and platelet adhesion. Considerably less attention, however, has been paid to the accumulation of NO-related products in the vascular wall itself. Such local storage of NO products could conceivably contribute to the local regulation of blood flow and provide additional anti-adhesive protection, if biochemically activated to regenerate NO. Since little is known about their chemical nature, concentrations, and possible role in vascular biology we sought to characterize those species basally resent in rat aorta. To this end we developed a functional form of optical spectroscopy that allows us not only to identify NO-stores in intact tissues but also to monitor their production and disappearance in real-time. The method is based on the ability of NO stores to reversibly release NO when illuminated with light of particular wavelengths, which can be detected as a robust relaxation of vascular smooth muscle (photorelaxation). Characterization of NO-stores is achieved through a careful assessment of photorelaxation action spectra, taking into account the light scattering properties of the tissue, and of depletion of the NO-stores induced by exposure to controlled levels of light. This functional form of optical spectroscopy is applied to rat aortic tissue where the results suggest that the NO photolytically released from tissue stores originated from a low-molecular-weight RSNO as well as from nitrite. The significance of these findings to vascular physiology and pathophysiology is discussed.

We have performed cerebral near-infrared spectroscopy (NIRS) and polysomnography (electro-encephalography, electro-oculography, electro-myography, pulse oximetry, and respiratory monitoring) during all-night sleep in five human subjects. Polysomnography data were used for sleep staging, while NIRS data were used to measure the concentration and the oxygen saturation of hemoglobin in the frontal brain region. Immediately after sleep onset we observed a decrease in the cerebral concentration of oxy-hemoglobin ([HbO₂]) and an increase in the concentration of deoxy-hemoglobin ([Hb]), consistent with a decrease in the cerebral blood flow velocity or an increase in cerebral metabolic rate of oxygen. An opposite trend (increase in [HbO₂] and decrease in [Hb]) was usually observed after transition to deep sleep (stages III and IV). During rapid eye movement (REM) sleep, we observed an increase in [HbO₂] and decrease in [Hb], consistent with an increase in the cerebral blood flow that overcompensates the increase in the metabolic rate of oxygen associated with REM sleep.

Diffusing Wave Spectroscopy (DWS) is a novel modern technique uniquely suited for the non-invasive measurements of the particles size and their motion within the randomly inhomogeneous highly scattering and absorbing media, including biological tissues as a human skin. The technique is based on the illuminating the media (tissues) with a coherent laser light, and analyzing the loss of coherence of the scattered field arises from motion of the scattering particles with respect to each other. Both theoretical and experimental results has shown the potentialities and viability of DWS application for the express non-invasive quantitative monitoring and functional diagnostics of skin blood microcirculation, with down to 1 μm/sec resolution. This is likely lead to quantitative monitoring in general diagnostics, diabetes studies, pharmacological intervention for the failing surgical skin flaps or replants, blood microcirculation monitoring during sepsis, assess burn depth, diagnose atherosclerotic disease, and investigate mechanisms of photodynamic therapy for cancer treatment. In frame of current report we describe the recent developments of DWS further to the point that skin blood micro-flow can be routinely and accurately obtained in a separate skin vascular bed on normal skin tissues.

We review a new theoretical description of the optical coherence tomography (OCT) geometry for imaging in highly scattering tissue. The new model is based on the extended Huygens-Fresnel principle, and it is valid in the single and multiple scattering regimes. Furthermore, we simulate the operation of the OCT system using a specially adapted Monte Carlo simulation code. To enable Monte Carlo simulation of the coherent mixing of the sample and reference beams the code uses a method of calculating the OCT signal derived using the extended Huygens-Fresnel principle. Results obtained with the Monte Carlo simulation and the new theoretical description compare favorably. Finally, the application of the extended Huygens-Fresnel principle for extracting optical scattering properties is used to obtain a so-called true reflection algorithm.

Optical trapping techniques are widely used for micromanipulation of biological molecules and cells. Advanced design of optical traps including focused Gaussian, Bessel beams are described depending upon optical trap function and possible applications. The basic theory of harmonic potential well is developed for a full description of particle dynamics. It is shown that stochastic resonance phenomena are also involved in essential of diffusion dynamics of Brownian particle in tailored potentials.

A fiber optic biosensor to monitor mutans streptococci activity in human saliva is discussed. The developed biosensor is based on the selective bacterial growth medium and evanescent wave spectroscopy at the core-cladding interface of a multimode fiber to monitor the bacterial mediated biochemical reaction. In order to achieve this, a short length of the cladding is removed; the fiber core surface is treated and coated with a thin film of porous glass medium using sol-gel technique. During experiments, the mutans streptococci mediated reaction with sucrose is monitored using a photosensitive indicator, which is immobilized within the porous glass coating. This investigation highlights the potential benefits of the FOBS to monitor mutans streptococci activity in saliva.

Laser-induced fluorescence spectra were obtained during the exposure of lamb heart (n=20) tissue to Argon-ion radiation (457.9nm). Fluorescence spectra from different heart compartments (the left and right atria and ventricles, the myocardium, the epicardium, and the aorta) were recorded. Simple algebraic algorithms based on the spectral intensity variation were constructed in order to detect spectral features and characterize the different cardiac compartments. Additionally, it was investigated whether each chamber exhibited constant spectral response. After the end of each experiment the lamb hearts were stored in formalin (10%). The samples were irradiated again after forty eight (48) hours in order to investigate the spectral differences that appear due to formalin conservation. Similar fluorescence measurements were taken from a limited number of human heart tissues (n=2) ex vivo.

Tumor cells are more sensitive to temperature increase than normal tissue. Hyperthermia has been used as a potential modality for cancer treatment. Another benefit from the thermal interruption of tumor cells is the immunological reactions, caused by inflammation and other mechanisms, and more interestingly caused by antigen(s) release. The temperature control is crucial both in direct tumor destruction through acute thermal effect and in immune reactions. Low temperature may not achieve the desired tumor cell killing. High temperature could result in over heating of the tumor, hence introducing undesirable damage to surrounding normal tissue. High temperature could completely denature the cell proteins, hence rendering tumor antigen(s) useless in immunological stimulation. A combination of an 805-nm laser and in-situ indocyanine green (ICG) solutions were used in treating rat tumors. Temperature measured at different locations showed that the effective photothermal interaction could reach as deep as 1 cm below the treatment surface and the temperature inside the tumor can be controlled by the laser and dye parameters. Multiple beams were also used to irradiate the tumor. When the tumor is free of ICG, the temperature increase of the tumor was less significant under the laser irradiation with a power density of 0.33 W/cm²; tumor tissue at a depth of 1 cm only experienced a 7°C-temperature increase. However, when the tumor contained ICG solution, the temperature at 1-cm depth experienced more than 15°C-temperature increase. Multiple-fiber irradiation further enhanced the photothermal selectivity. Furthermore, when one fiber was used, the edge of the tumor experienced less impact by the laser beam, while multiple beams resulted in an almost uniform temperature increase over the entire tumor.

In this paper we present recent results of our studies on the development and tests of: 1) optoacoustic monitoring of cerebral blood oxygenation; 2) optical coherence tomography for accurate measurement of tissue optical properties; and 3) ultrasound-enhanced anti-cancer drug delivery. Major experimental results obtained in vitro and in vivo with the use of these techniques are reported and discussed.

In order to study the behavior of cerebral physiological parameters and to further the understanding of the fMRI blood-oxygen-level-dependent (BOLD) effect, we have recorded simultaneously multi-source frequency-domain near-infrared and BOLD fMRI signals during motor functional activation in humans. From the near-infrared data we obtained information on the changes in cerebral blood volume and oxygenation. In order to relate our observations to changes in cerebral blood flow we employed the “balloon” model of cerebral perfusion. Our data showed that the deoxyhemoglobin concentration is the major factor determining the time course of the BOLD signal.

Spectronephelometric measurement techniques are in the order of the day. We can apply these techniques to monitor the production of consumable fluids and to verify their quality. Products like Wine, Beer and Olive Oil for instance, are widely consumed over the world. These products do have a major role in people’s dietary habits and their quality is of greater concern from day to day. If we can make use of a monitoring system that is able to perform measurements in situ, on line and in real time, then we will obviously have the capacity to improve quality. Particles that are suspended in consumable fluid samples interact with radiation by scattering it in almost all directions. If we can detect this scattered radiation, then we have information on the suspended particles. Making use on some Physical relations, we can transpose this information to physical parameters like Color and Turbidity.

Particle measurement is important in many applications such as the manufacture of drugs and paints, and aerosols. In bioimaging there is interest understanding the imaging of nanoparticles and subcellular scatterers. We present in this paper a wide field, phase measuring confocal microscope that can be used for such measurements. The wide field confocal response is obtained by illuminating both sample and reference arms of an interferometric microscope with nominally identical speckle patterns. When the speckle patterns are highly correlated the interference is significant. Contributions from out of focus planes result in uncorrelated speckle patterns and no interference. This provides a wide field confocal response. High speed measurements are enabled by parallel phase stepping using polarization optics. We have also developed a vector diffraction microscope model, using Mie theory as a scattering function, to validate the images of small particles. Correctly scaling the amplitudes of the unscattered and scattered electric fields enables co-polar transmission imaging to be modeled. Finally it is demonstrated that the phase is a more sensitive measurement of particle size than the amplitude.

Laser Doppler fluxmetry (LDF) or photopletysmography (PPG) are frequently used as non-invasive tools for the detection of the so-called “inspiratory gasp response” (IGR), a vasoconstrictive episode provoked by a voluntary deep inspiration. According to our knowledge, a rigorous comparison of both methods has not been reported in the literature. Therefore, the aim of the study was to compare the detection of IGR with LDF and PPG. We investigated 14 young and healthy volunteers. A PPG and a LDF probe were applied to adjacent fingertips of the dominant hand (thumb/index finger). After baseline measurements the subjects were asked to perform a deep inspiration with time intervals of 90 sec., 60 sec., 30 sec., and 15 sec. We found that both methods are useful to detect individual IGR. However, overall correlation of IGR amplitude detected with LDF and PPG was poor (r=0.433). Surprisingly, there was a continuous increase of the correlation coefficient from the first (r=0.105) or second (r=0.184) IGR to the fifth (r=0.727) IGR. These results imply that experimental data obtained with PPG and LDF are not equivalent and therefore one has to be cautious regarding the comparison and interpretation of results obtained with these two different methods.

A review is presented of the developments in Kent in the field of optical coherence tomography (OCT) based instrumentation. Original versatile imaging systems have been devised which allow operation in different regimes under software control. Using such systems, B-scan and C-scan images are demonstrated from retina, anterior chamber, skin and teeth. The systems developed in Kent employ the flying spot concept, i.e. they use en-face scanning of the beam across the target. This has opened the possibility of providing simultaneous en-face OCT and confocal images (C-scans). Application of a standalone OCT/confocal system for investigating the retina in eyes with pathology, the anterior chamber, skin and teeth is demonstrated.

The spatio-temporal characteristics of changes in cerebral blood volume associated with neuronal activity were investigated in the hindlimb somatosensory cortex of α-chloralose/urethan anesthetized rats (n=10) with optical imaging at 570nm through a thinned skull. Activation of cortex was carried out by electrical stimulation of the contralateral sciatic nerve with 5Hz, 0.3V pulses (0.5ms) for duration of 2s. The stimulation evoked a monophasic optical reflectance decrease at cortical parenchyma and arteries sites rapidly after the onset of stimulation, whereas no similar response was observed at vein compartments. The optical signal changes reached 10% of the peak response 0.70±0.32s after stimulation onset and no significant time lag in this 10% start latency time was observed between the response at cortical parenchyma and arteries compartments. The evoked optical reflectance decrease reached the peak (0.25%±0.047%)2.66±0.61s after the stimulus onset at parenchyma site, 0.40±0.20s earlier (P<0.05) than that at arteries site (0.50%±0.068% 3.06±0.70s). Variable location within the cortical parenchyma and arteries compartment themselves didn’t affect the temporal characteristics of the evoked signal significantly. These results suggest that the sciatic nerve stimulation evokes a local blood volume increase at both capillaries (cortical parenchyma) and arterioles rapidly after the stimulus onset but the evoked blood volume increase in capillaries could not be entirely accounted for by the dilation of arterioles.

A single fiber may be employed to emit and collect light from a optically diffusing medium such as biological tissues. However, the light collected by the fiber consists of two components: diffusely scattered light from within the tissue and specularly reflected light from the surfaces. Only the diffuse reflection contains the desired information regarding the optical absorption and scattering properties of the tissue, but the specular component is comparable in magnitude to the diffuse reflection with visible light. The refractive index mismatch between the fiber and tissue account for a portion of the specular reflection. However, imperfect contact of the fiber with the surface of tissue creates additional boundaries and thus additional specular reflections. Experiments are performed with a 200 micron diameter fiber and a 632.8 nm He-Ne source to characterize the specular reflection collected through the same fiber using water as a coupling medium. The angular collection efficiency is measured for a fiber in contact with the surface on a glass substrate (specular reflection only) and an epoxy resin tissue phantom (specular and diffuse reflection components). Next, the collection efficiency is measured for a separation between the fiber and the samples for perpendicular illumination to the surface, 14 degrees, and 25 degrees from normal. Imperfect contact is demonstrated to vary the amount of specular reflection collected using a single fiber where changes in angle greater than 4 degrees or a separation between the fiber and the surface in excess of 400 micron caused a minimum of 7 percent reduction of the collected specular reflection.

A Rayleigh interferometer was constructed to measure changes of concentrations in the biological solutions. With the stability tests, our Rayleigh interferometer system showed its insensitivity to environment vibrations and with the second compensating cuvette, effects on the refractive index changes other than the concentration changes of molecules in the sample solution could be compensated. A thin glass plate was inserted in the beam path and rotated to vary the optical path length to test the sensitivity of the system. With this glass plate, the detectable optical path differences of the system was Δ(nl) = 7 nm. Finally, the concentration of sucrose solutions were varied to change the refractive index. The refractive index changes by 1.43 × 10^-4 for each gram of sucrose per liter at 20°C. With our system, the sensitivity to sucrose solution was 7mg/L. Based on this sensitivity this interferometric system can be used to detect concentrations of albumin solutions as low as 0.6mg/mL.

Polarized light imaging can facilitate clinical mapping of skin cancer margins and can potentially guide clinical excision. A real-time hand-held polarized-light system was built to image skin lesions in the clinic. The system consisted of two 8-bit CCD cameras (Camera 1 and Camera 2) mounted on the camera assembly and illuminated the patient’s skin. Light was polarized parallel to the source-patient-camera plane. The light, reflected from the patient, was collected with an objective lens mounted on the beam splitter and divided into a horizontal (H) and vertical (V) component. The H component was collected by Camera 1, and the V component was collected by Camera 2. A new image was generated based on the polarization ratio (H - V)(H + V) and displayed. This image was sensitive to the superficial skin layer and some early clinical examples are presented. A web version of this paper is available at the following web site: optics.sgu.ru/SFM/2002/internet/Jessica/.

Approximately 14 million people in the USA and more than 140 million people worldwide suffer from Diabetes Mellitus. The current glucose sensing technique involves a finger puncture several times a day to obtain a droplet of blood for chemical analysis. Recently we proposed to use optical coherence tomography (OCT) for continuous noninvasive blood glucose sensing through skin. In this paper we tested the OCT technique for noninvasive monitoring of blood glucose concentration in lip tissue of New Zealand rabbits and Yucatan micropigs during glucose clamping experiments. Obtained results show good agreement with results obtained in skin studies, good correlation of changes in the OCT signal slope measured at the depth of 250 to 500 μm with changes in blood glucose concentration, and higher stability of the OCT data points than that obtained from skin.

Monte Carlo method was implemented to simulate random photon transport inside an infinitely wide layer of highly scattering medium. Temporal distributions of intensity of light passing through the sample for different initial Gaussian pulse durations, dependences of number of scattering events, distributions of photons absorbed and scattered inside the medium are analyzed and compared to the experimental data, obtained for different parameters of the medium.

To investigate the effects of PUVA (psoralen + UVA-irradiation) and photooxidized psoralen (POP) on cell-cell junctions, two kinds of multicellular spheroids, which were grown from HeLa cells of epithelioid human cervix carcinoma, were used as a model systems: i) defective in intercellular communication through gap junctions (HeLa-spheroids) and ii) transfected with coding sequences of murine connexin Cx43 with restored gap-junction coupling (HeLa-Cx43-spheroids). It was been found that both PUVA and POP induced disaggregation of HeLa-spheroids as well as HeLa-Cx43-spheroids. It implies that gap-junction plaques are not, apparently, critical targets in psoralen-photosensitized disaggregation. The rate of disaggregation was estimated as inverse time of disaggregation of 50% or 100% spheroids in suspensions (1/t₅₀ or 1/t₁₀₀, respectively). The rate of PUVA-induced disaggregation was found to increase with the increase of UVA-fluence up to 85 kJ/m². Photosensitization coefficient was highest at low UVA-fluences (4-6 kJ/m²) and significantly decreased with increase in UVA-fluence. The viability of cells in spheroids was estimated with the use of trypan blue stain. At low UVA-fluences, the process of disaggregation was found to occur without the formation of trypan positive cells in spheroids. Results obtained evidence that PUVA-induced disaggregation of spheroids may occur, at least partially, through the action of POP-products.

In this work we used angle-resolved Monte-Carlo simulation to study light propagation in non-aggregated RBC suspensions. In our model we used phase functions, calculated in different optic approximation (geometrical optics, Fraunhofer diffraction, hybrid approximation, Mie theory) as well Heyney-Greenstein function. Scattering indicatrices obtained in different approximations were compared. Heyney-Greenstein function was used for calculations at different hematocrits. It was shown that for hematocrits in a range of 20...50 % the scattering indicatrices for wavelength 633 nm do not differ significantly, however this difference is higher fro smaller hematocrit. We also compared contributions of single and multiple scattering to light intensity distribution at different angles. We showed that for 100-μm thick suspension layer the major contribution to forward scattering is given by snake-photons, while to backward scattering - by multiply scattered photons.

The novel Monte Carlo technique of simulation of spatial fluorescence distribution within the human skin is presented. The computational model of skin takes into account spatial distribution of fluorophores following the collagen fibers packing, whereas in epidermis and stratum corneum the distribution of fluorophores assumed to be homogeneous. The results of simulation suggest that distribution of auto-fluorescence is significantly suppressed in the NIR spectral region, while fluorescence of sensor layer embedded in epidermis is localized at the adjusted depth. The model is also able to simulate the skin fluorescence spectra.

The results of statistical analysis of spectra of intensity fluctuation of light, scattered from oral cavity membrane and teeth pulp, are presented. The dependence of the spectral moments of speckle-interferometric signal on the cutoff frequency is investigated. Influence of own noise of measuring system on formation of speckle-interferometric signal is studied. Dependencies of scattering properties of biotissues on characteristics of speckle interferometric and Doppler signals are analyzed. New algorithms to statistical processing of measuring are suggested.

The peculiarities of movement of red blood cells and blood plasma in very narrow capillaries are analyzed in this paper. The characteristics of blood cell motion in the isolated microvessel are considered on the base of theoretical works of Lighthill and Fitz-Gerald. Capillaries with diameter a rather larger than erythrocyte size are investigated in details. Optical model of blood microflow in the smallest capillaries is developed. Process of diffraction of strongly focused laser beam from such vessel is considered. The shapes of Doppler spectra of scattering intensity fluctuations are studied. Relations between the spectral characteristics of dynamic speckles scattered from RBC, moving in blood plasma, and the hydrodynamic characteristics of microflow are found.

The results of statistical analysis of Doppler spectra of intensity fluctuations of light, scattered from mucose membrane of oral cavity of healthy volunteers and patients, abused by the orthodontic diseases, are presented. Analysis of Doppler spectra, obtained from tooth pulp of patients, is carried out. New approach to monitoring of blood microcirculation in orthodontics is suggested. Influence of own noise of measuring system on formation of the speckle-interferometric signal is studied.

The surface of rejected dental implants was studied. It was clarified that the implant rejection happened in a case of incomplete osteointegration of implants, incomplete proliferation of a bone tissue in holes. In a turn, osteointegration depends on uniformity of deposition of a titanium-hydroxyapatite (Ti/HA) coating and the impurities composition of used materials. The excess of exterior elements imported at technological processes also influences on adhesion.

One of the most attractive perspectives for modern medicine is to solve a problem of a superfluous weight. Method of solving the problem by means of a light source initiates to study optical characteristics of fatty tissue in details. This paper studies temperature dynamic of IR, NIR and visible spectrum of fatty tissue. It refers to temperature, spectra absorption bands and aggregation state of fatty tissue. Character of spectrum changes close to temperatures complying with the change of in-vitro fatty tissue condition is a subject of author’s particular attention.

The T-matrix method together with the approximate theories such as the Rayleigh-Gans and anomalous diffraction approximations are used for the refractive index determination of bacterial cells from spectral extinction measurements. The water suspension of Escherichia coli K12 cells in exponential phase of growth is modeled as a system of randomly oriented homogeneous circular cylinders with identical radii and different lengths. In the case of length monodispersity the results of the approximate theories are compared with those obtained by the exact T-matrix method. Assuming the gamma distribution of bacterial lengths, the influence of the length polydispersity on the refractive index is investigated using the Rayleigh-Gans approximation. It is shown that the effect of the length polydispersity degree upon the refractive index of rod-shaped bacteria is negligible. The wavelength dependence of the refractive index of E. coli cells obtained gives the value of 1.397 at 589 nm what is in a good agreement with the result of immersion refractometry (1.395±0.005).

A simple modification of the Rayleigh-Gans approximation for homogeneous prolate cylinders are presented. It is shown that the structure of the phase function, calculated by the modified Rayleigh-Gans approximation, is more close to that, obtained by the T-matrix method, then do the classical Rayleigh-Gans approximation.

The human blood optical parameters have been calculated based on Mie theory. The calculations have been done in the spectral range from 400 nm to 1000 nm, which is of great interest due to usage of many therapeutic and diagnostic technologies. The influence of an immersion agent, like glucose, on optical properties of blood, has been studied.

Water is the most important biological liquid. On the basis of literature data we present a simple approximation of water refractive index in dependence on temperature and wavelength in the spectral range from 200 to 1000 nm. The approximation is important for different applications in biomedical optics and optics of tissues.

We have studied morphine action on mobility and structure of water by means of fluorescent investigations and light scattering analysis. Wave-like concentration dependences have been plotted in the both cases. Theoretical description of the discovered effect has been made based on the formalism of N.N.Bogolubov.

The temporal behavior of autofluorescence of human skin and epidermis under continuous UV-irradiation has been studied. Fluorescence spectra and kinetic curves of fluorescence intensity have been obtained. The fluorescence intensity recovery after dark period also has been examined. The vitiligo skin and epidermis were used for comparing their spectra with reflectance and fluorescence spectra of healthy skin. The epidermal samples were prepared using surface epidermis stripping technique. It has been concluded that fluorophores being undergone the UVA photobleaching are actually present in epidermal layer, and immediate pigment darkening does contribute, no less than a half of magnitude, to the autofluorescence decrease under continuous UVA irradiation.

A new versatile near-field scanning optical microscope (NSOM) for technical and biological application have been developed in our laboratory. The microscope can be operated in all known modes, viz., scanning optical, photon tunneling and apertureless photon tunneling modes. Different methods of NSOM tip production are discussed in the paper. The maximal displacement of the coarse adjustment unit is 1 mm the approach step is about 0,05 μm. The NSOM scanner consist of a mechanical scanner with large displacement range (1 mm) on which is mounted a fine piezoscanner with a scanning range about 4 μm. The maximal scanning range of the NSOM is about 1 mm laterally and 4 μm in perpendicular to sample surface direction with rough selection of area for study in the total area about 15x15 mm under conventional optical microscopy observation (maximal magnification 100). As a sample holder are used either a glass prism in photon tunneling mode or a flat glass in scanning optical mode. The microscope has a digital control unit connected with IBM PC through a parallel interface. The NSOM high rigidity makes it possible to operated in ordinary laboratory without any additional vibration isolation devices.

Considering enhanced angiogenesis in malignant tissues we propose in a new functional imaging technique. If proven in clinical trial, the technique may be useful for differentiating malignant tumors with enhanced vascularity from normal tissues and benign lesions. The technique is based on observing the dynamics of light attenuation in the breast tissue in response to an external pressure stimulus. The attenuation is related to blood flow and blood oxygenation. In the proposed technique the measurements are made in the red spectral wavelength region where hemoglobin serves as a natural contrast agent. In order to understand and interpret the temporal dynamic of attenuation or signatures, a model of blood circulation in zones of tumor and normal tissues is developed. The blood volume, blood flow, and oxygen saturation level are evaluated using a lumped fluid flow model incorporating published hemodynamics data obtained from biopsy samples or in-situ chamber growth of human tumor. The hemodynamics properties are translated into normal tissues. The results suggest that the differences in the transient response may be used as a secondary diagnostic tool in breast imaging or as a monitoring tool in anti-angiogenesis drug therapy.

A new model of low intensity laser irradiation action (LILI) on biological objects on cell level was suggested. Up to this model the effect of LILI action is a result of that fact that laser light irradiation due to it coherence can obtain periodical character (interference picture or speckle-structure) with small enough periods of dark and light parts changing comparable with cell or cell organelles sizes. In this conditions inhomogeneous light absorption can lead to electrical field appearance (Dember effect), which can change the character of photostimulated reactions and change membrane charge condition either of cell itself or of its organelles, that is lead to cell life cycle shifts.

We studied photodynamic action of LED radiation (660 nm) sensitized by Methylene Blue on bacteria strain Staphylococcus 209 P. Method efficiency was compared with photodynamic action of He-Ne laser radiation (632,8 nm). Methylene Blue was proved to possess good photosensitizing properties and its application in photodynamic therapy of pyoinflammatory diseases was found advantageous.

Staining technique and NIR LED based setup has been developed for study of photodynamic action (PDA) of Indocyanine Green (ICG) on Staphylococcus Aureus. ICG appeared sufficiently effective PDA photosensitizer acceptable for grampositive bacterial cultures effective suppression. The efficiency of PDA was estimated as 89%.

The outcomes of experiments on a research of in vivo human organism response for the influence of the low intensity optical radiation are presented. The dynamics of spectral intensity of backscattering diagnostic radiance was registered. It was shown, that the biotissues optical properties alteration process has similar character in a whole investigated optical range from 430 up to 860 nm and its kinetics was explained by the field model mechanism of interaction.

Sulphonated alumophthalocyanine Photosens AIPcS_n (mean n= 3.1) localizes predominately in the glial envelope surrounding the crayfish stretch receptor neuron. PDT treatment of the isolated stretch receptor organ with 10^-7 M Photosens inhibits and then irreversibly abolishes neuron activity for approximately 20 min. Then, in 1.7 h after PDT treatment, the plasma membrane loses its integrity and propidium iodide enters into the cytosol and stains the nuclear chromatin. Neuron nucleus progressively shrinks but apoptotic nucleus fragmentation is not occurred. This neuron death type is delayed necrosis. Nuclei of the satellite glial cells also shrink. In 8 h after PDT treatment some of them become fragmented that is characteristic for apoptosis, whereas others lose the plasma membrane integrity and die through necrosis. However, glial cells not only die but also proliferate under PDT treatment and their number is increased. This gliosis is probably aimed to neuron saving.

Distinction of hypodermic lipocells of practically healthy people and patients with NIDDM to temperature eposure is revealed. This distinction is caused not only by the peak size difference of lipoblasts in practically healthy people and in insulin metabolism disorders, but in the greater degree - by distinction of morpho-functional properties of lipocell membrane of practically healthy donors and patients with noninsulindependent mellitus.

Flow cytofluorometric DNA analysis was applied to determine of the relative contents of proliferative (more then 2C DNA per cell) and apoptotic (less then 2C DNA per cell) leukocytes in blood of adult rabbits, challenged with 10,000 times the 50 % effective dose of Vibrio cholerae virulent strain by the RITARD technique. It has been shown that irreversible increase the percentage of cells carrying DNA in the degradation stage brings to disbalance between the genetically controlled cell proliferation and apoptosis that leads to animal death from the cholera infection. Such fatal changes were not observed in challenging of immunized animals that were not died. Thus received data show that the flow cytofluorometric measurements may be used for detection of transgressions in homeostasis during acute infection diseases, for outlet prognosis of the cholera infection.

No abstract available

The series of workshops on academic writing have been developed by academic writing instructors from Language Teaching Centre, Central European University and presented at the Samara Academic Writing Workshops in November 2001. This paper presents only the part dealing with strucutre of an argumentative essay.

Computers have opened doors to the new era of telecommunication. Electronic mail is becoming very popular in different spheres of professional activity and everyday life of people all over the world as it provides people an excellent opportunity for real, natural communication. The use of e-mail and the Internet involves a whole range of skills including knowing how to use a personal computer, knowing how to navigate the immense resources of cyberspace, and becoming familiar with the special register of e-mail communication (which lies somewhere between the formality of traditional writing and the spontaneity of speech). Conferencing via e-mail, or communicating with partners through networked computers, offers many opportunities in the Scientific Community. E-mail allows us to collaborate easily with thousands of colleagues, sharing new ideas, resources, and materials. It can provide the information, contacts, and stimulation that can make our research work more effective and enjoyable. The English language is world-wide accepted as lingua-franca of the Internet and intercultural communication. This brings us to a necessity to introduce some ideas on e-mail writing.

The article focuses on the current problem of teaching English for Specific Purposes(ESP) language vocabulary taking into consideration the ways how learners store and recall words and the influence of their mother tongue. Through incidental learning and explicit vocabulary instructions the elaborated vocabulary learning occurs involving the creation of an affective semantic network.