This PDF file contains the front matter associated with SPIE Proceedings Volume 9531 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Full-field optical coherence tomography (FF-OCT) is a biomedical imaging technique based on white-light interference microscopy. FF-OCT produces tomographic images by arithmetic combination of interferometric images acquired with an area camera and by illuminating the whole field to be imaged with low-coherence light. The major interest for FFOCT lies in its high imaging resolution in both transverse and axial directions using a simple and robust experimental arrangement. This paper provides an overview of the principle of FF-OCT. The system characteristics are reported in details, including the detection sensitivity and spatial resolution. Several of the challenges, advantages and drawbacks of the technique are discussed and compared with other optical imaging techniques such as conventional OCT and confocal microscopy. Images of normal and diseased human breast tissue are presented to illustrate the potential of FF-OCT for cellular-level anatomopathological examinations without sample processing.

Due to their high number of supported modes, multimode optical fibers carry large amount of spatio-temporal information. However, propagation of a light pulse through a multimode optical fiber suffers from spatial distortions due to superposition of the various exited modes and from time broadening due to modal dispersion. Here, we present a method based on digital phase conjugation to selectively excite specific optical fiber modes in a multimode fiber that follow similar optical paths as they travel through the fiber. In this way, they can be made to interfere constructively at the fiber output to generate an ultrashort spatially focused pulse. The excitation of a limited number of modes limits modal dispersion, allowing the transmission of an ultrashort pulse. We also show that the short spatially focused pulse can be scanned digitally without movable elements. We experimentally demonstrate that the pulse at the output of the multimode fiber generate a two-photon signal. We show delivery of a 1550 nm pulse with 500 fs duration, spatially focused to a spot size of 7 micrometers, through a 30 cm long, 200 micrometers core multimode step-index fiber. We show how this technique is applied to endoscopic two-photon imaging.

The collagen fibers are one of the most important structural proteins in skin, being responsible for its strength and flexibility. It is known that their properties, like fibers density, ordination and mean diameter can be affected by several skin conditions, what makes these properties a good parameter to be used on the diagnosis and evaluation of skin aging, cancer, healing, among other conditions. There is, however, a need for methods capable of analyzing quantitatively the organization patterns of these fibers. To address this need, we developed a method based on the autocorrelation function of the images that allows the construction of vector field plots of the fibers directions and does not require any kind of curve fitting or optimization. The analyzed images were obtained through Second Harmonic Generation Imaging Microscopy. This paper presents a concise review on the autocorrelation function and some of its applications to image processing, details the developed method and the results obtained through the analysis of hystopathological slides of landrace porcine skin. The method has high accuracy on the determination of the fibers direction and presents high performance. We look forward to perform further studies keeping track of different skin conditions over time.

Changes in the ultrastructure of collagen in various tumor and non-tumor human tissues including lung, pancreas and thyroid were investigated ex vivo by a polarization-sensitive second harmonic generation (SHG) microscopy technique referred to as polarization-in, polarization-out (PIPO) SHG. This involves measuring the orientation of the linear polarization of outgoing SHG as a function of the linear polarization orientation of incident laser radiation. From the PIPO SHG data, the second-order nonlinear optical susceptibility tensor component ratio, χ⁽²⁾ ZZZ’/χ⁽²⁾ ZXX’, for each pixel of the SHG image was obtained and presented as color-coded maps. Further, the orientation of collagen fibers in the tissue was deduced. Since the χ⁽²⁾ ZZZ’/χ⁽²⁾ ZXX’ values represent the organization of collagen in the tissue, theses maps revealed areas of altered collagen structure (not simply concentration) within tissue sections. Statistically-significant differences in χ⁽²⁾ ZZZ’/χ⁽²⁾ ZXX’ were found between tumor and non-tumor tissues, which varied from organ to organ. Hence, PIPO SHG microscopy could potentially be used to aid pathologists in diagnosing cancer. Additionally, PIPO SHG microscopy could aid in characterizing the structure of collagen in other collagen-related biological processes such as wound repair.

Nanotechnology offers a targeted approach to both imaging and treatment of cancer, the leading cause of death worldwide. Previous studies have found nanoparticles with a wide variety of coatings initiate an immune response leading to sequestration in the liver and spleen. In an effort to find a nanoparticle platform which does not elicit an immune response we created 43/44 nm gold or silver nanoparticles coated with biomolecules normally produced by the body, α-lipoic acid and the Epidermal Growth Factor (EGF), and have used mass spectroscopy to determine their biodistribution in mouse models, 24 hours following tail vein injection. Relative to controls, mouse EGF (mEGF) coated silver and gold nanoprobes are found at reduced levels in the liver and spleen. mEGF coated gold nanoprobes on the other hand do not appear to elicit any immune response, as they are found at background levels in these organs. As a result they should remain in circulation for longer and accumulate at high levels in tumors by the enhanced permeability retention (EPR) effect.

Water-based materials are commonly used in phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. Styrene-Ethylene/Butylene-Styrene (SEBS) copolymer in mineral oil samples were made varying the SEBS concentration between 5─15%, and low-density polyethylene (LDPE) between 0−9%. Acoustic properties such as speed of sound and attenuation coefficient were obtained by the substitution technique with frequencies ranging from 2.25─10 MHz, and were consistent to that of soft tissue. These properties were controlled varying SEBS and LDPE concentration; speed of sound from 1445─1480 m/s, and attenuation from 0.86─11.31 dB/cm were observed. SEBS gels with 0% of LDPE were optically transparent, presenting low optical absorption and scattering coefficients in the visible region of the spectrum. In order to fully characterize the optical properties of the samples, the reflectances of the surfaces were measured, along with the absorption. Scattering and absorption coefficients ranging from 400 nm to 1200 nm were calculated for each compound. The results showed that the presence of LDPE increased absorption and scattering of the phantoms. The results suggest the copolymer gels are promising for ultrasound and optical imaging, what make them also potentially useful for photoacoustic imaging.

Clinical symptoms of diabetic retinopathy are not detectable until damage to the retina reaches an irreversible stage, at least by today’s treatment standards. As a result, there is a push to develop new, “sub-clinical” methods of predicting the onset of diabetic retinopathy before the onset of irreversible damage. With diabetic retinopathy being associated with the accumulation of long-term mild damage to the retinal vasculature, retinal blood vessel permeability has been proposed as a key parameter for detecting preclinical stages of retinopathy. In this study, a kinetic modeling approach used to quantify vascular permeability in dynamic contrast-enhanced medical imaging was evaluated in noise simulations and then applied to retinal videoangiography data in a diabetic rat for the first time to determine the potential for this approach to be employed clinically as an early indicator of diabetic retinopathy. Experimental levels of noise were found to introduce errors of less than 15% in estimates of blood flow and extraction fraction (a marker of vascular permeability), and fitting of rat retinal fluorescein angiography data provided stable maps of both parameters.

Active dynamic thermography (ADT) is an imaging technique capable of characterizing the non-homogenous thermal conductance of damaged tissues. The purpose of this study was to determine optimal stimulation parameters and quantify the optical resolution of ADT through various depths of human skin. Excised tissue from plastic surgery operations was collected immediately following excision. A total of 12 thin to thick split-thickness grafts were harvested from 3 patients. Grafts were placed on top of a 3D printed resolution chart and thermal stimulation was applied from a 300W halogen lamp array for between 0.5-10 seconds to determine optimal parameters. Video was captured with a thermal camera, and analysis was performed by reconstructing an image from thermal gradients. In this study ADT resolved 0.445±0 lp/mm at a depth of 0.010”, 0.356±0.048 lp/mm at a depth of 0.015”, 0.334±0.027 lp/mm at a depth of 0.020” and 0.265±0.022 lp/mm at a depth of 0.025”. The stimulus energy required for maximum resolution at each depth was 3- 4s, 8s, 12s and 12s respectively. ADT is a sensitive technique for imaging dermal structure, capable of resolving detail as fine as 1124 μm, 1427 μm, 1502 μm and 1893 μm in thin to thick split-thickness skin grafts respectively. This study has characterized a correlation between stimulus input and maximal resolution at differing depths of skin. It has also defined the functional imaging depth of ADT to below the sub-cutis, well below conventional spectrophotometric techniques.

The paper presents a novel combined approach aimed to detect and monitor singlet oxygen molecules in biological specimens by means of the simultaneous recording and monitoring of their deactivation dynamics in the two complementary channels: radiative and nonradiative. The approach involves both the direct registration of phosphorescence at the wavelength of about 1270 nm caused by radiative relaxation of excited singlet oxygen molecules and holographic recording of thermal disturbances in the medium produced by their nonradiative relaxation. The data provides a complete set of information on singlet oxygen location and dynamics in the medium. The approach was validated in the case study of photosensitized generation of singlet oxygen in onion cell structures.

Introduction: To date, it has never been demonstrated the propagation sound speed in human corneas and lens in vivo. With the advent of Optical Coherence Tomography (OCT), it became possible to determine the dimensions of the ocular tissues without the interference of sound propagation speed and to use this information to define the real propagation sound speed for each patient and individualized structure. Aim: To determine the sound propagation speed in the cornea and lens from patients that theoretically exhibits differences in tissue elasticity (normal corneas and keratoconus, corneas of young and elderly patients, in addition to clear crystalline lens from young and elderly patients with cataract). Then, relate the determined velocity in each group with the expected tissue elasticity of the cornea and lens. Methods: We studied 100 eyes from 50 patients: 50 with keratoconus and no cataract and 50 with cataract and no corneal changes. All patients measured corneal and lens thickness by ultrasound methods (Ultrasonic Biomicroscopy - UBM and Ultrasonic Pachymetry - USP) and by OCT (RTVue®, Lenstar® and Visante®), then were divided into 2 groups: Group 1 (Cornea) analyzed the central corneal thickness (UBM, USP, RTVue®, Visante®, Lenstar®); Group 2 (Lens) analyzed the axial thickness of the lens (UBM and Lenstar®). Based on standard ultrasonic speed from USP (1640 m/s) and UBM (1548 m/s), we calculated the real sound propagation speed in each tissue. Results: Based on USP, the corneal sound speed on control group (1616 m/s) was faster than on keratoconus group (1547 m/s) (P < 0.0001). Based on UBM, the lens sound speed on cataract group (1664 m/s) was faster that on control group (1605 m/s) (P < 0.0001). Discussion: It is known that sound propagates faster in materials with lower elasticity. We found that the sound speed on keratoconic corneas (high elasticity) was slower and on cataract lens (lower elasticity) was faster than normal corneas and lens in vivo.

Evaluating transplantation grafts at harvest is essential for its success. Laser-induced fluorescence spectroscopy (LIFS) can help monitoring changes in metabolic/structural conditions of tissue during transplantation. The aim of the present study is to correlate LIFSobtained spectra of human hepatic grafts during liver transplantation with post-operative patients' mortality rate and biochemical parameters, establishing a method to exclude nonviable grafts before implantation. Orthotopic liver transplantation, piggyback technique was performed in 15 patients. LIFS was performed under 408nm excitation. Collection was performed immediately after opening donor’s abdominal cavity, after cold perfusion, end of back-table period, and 5 min and 1 h after warm perfusion at recipient. Fluorescence information was compared to lactate, creatinine, bilirubin and INR levels and to survival status. LIFS was sensitive to liver changes during transplantation stages. Study-in-progress; initial results indicate correlation between fluorescence and life/death status of patients.

Endoscopy is frequently used in the diagnosis of several gastro-intestinal pathologies as Crohn disease, ulcerative colitis or colorectal cancer. It has great potential as a non-invasive screening technique capable of detecting suspicious alterations in the intestinal mucosa, such as inflammatory processes. However, these early lesions usually cannot be detected with conventional endoscopes, due to lack of cellular detail and the absence of specific markers. Due to this lack of specificity, the development of new endoscopy technologies, which are able to show microscopic changes in the mucosa structure, are necessary. We here present a confocal endomicroscope, which in combination with a wide field fluorescence endoscope offers fast and specific macroscopic information through the use of activatable probes and a detailed analysis at cellular level of the possible altered tissue areas. This multi-modal and multi-scale imaging module, compatible with commercial endoscopes, combines near-infrared fluorescence (NIRF) measurements (enabling specific imaging of markers of disease and prognosis) and confocal endomicroscopy making use of a fiber bundle, providing a cellular level resolution. The system will be used in animal models exhibiting gastro-intestinal diseases in order to analyze the use of potential diagnostic markers in colorectal cancer. In this work, we present in detail the set-up design and the software implementation in order to obtain simultaneous RGB/NIRF measurements and short confocal scanning times.

During the last decade, Optoacoustic Imaging (OAI), or Optoacoustic Tomography (OAT), has evolved as a novel imaging technique based on the generation of ultrasound waves with laser light. OAI may become a valid alternative to techniques currently used for the detection of diseases at their early stages. It has been shown that OAI combines the high contrast of optical imaging techniques with high spatial resolution of ultrasound systems in deep tissues. In this way, the use of nontoxic biodegradable contrast agents that mark the presence of diseases in near-infrared (NIR) wavelengths range (0.75–1.4 um) has been considered. The presence of carcinomas and harmful microorganisms can be revealed by means of the fluorescence effect exhibited by biopolymer nanoparticles. A different approach is to use carbon nanotubes (CNTs) which are a contrast agent in NIR range due to their absorption characteristics in the range between 800 to 1200 nm. We report a multi-wavelength (870 and 905 nm) laser diode–based optoacoustic (OA) system generating ultrasound signals from a double-walled carbon nanotubes (DWCNTs) solution arranged inside a tissue-like phantom, mimicking the scattering of a biological soft tissue. Optoacoustic signals obtained with DWCNTs inclusions within a tissue-like phantom are compared with the case of ink-filled inclusions, with the aim to assess their absorption. These measurements are done at both 870 and 905 nm, by using high power laser diodes as light sources. The results show that the absorption is relatively high when the inclusion is filled with ink and appreciable with DWCNTs.

Currently implants or tissue replacements are inserted either as a whole implant or by injecting a liquid which polymerizes to form a solid implant at the appropriate location. This is either highly invasive or not controllable. We developed a tool to perform such surgeries in a minimally invasive and controllable way. It combines photopolymerization and fluorescence spectroscopy in a surgical apparatus. However, to successfully replace tissue such as cartilage or an intervertebral disc, photopolymerizable materials do not only need to be photoactive. They should also be able to withstand the environmental loading conditions after implantation. Therefore we developed a set of in situ and in vitro tests adapted to the evaluation of photopolymerized tissue replacements and implants. In particular in this article, we report on a method, which combines photopolymerization and photorheology to track the current state of polymer during photopolymerization.

Opto-Acoustic Endoscopy (OAE) requires sensors with a high sensitivity and small physical dimensions in order to facilitate integration into an endoscope of less than 1mm in diameter. We present fibre Bragg grating (FBG) and Fabry- Perot intrinsic fibre sensors for ultrasound detection. We present a structure profile characterisation setup to analyse tune the fibre sensors in preparation for ultrasonic detection. We evaluate the suitability of the different structures and grating parameters for ultrasonic sensing. By analysing the prepared gratings, we enable the optimisation of the profile and a simplification of the detection regime for an optimal interferometric OAE configuration.

Pulchellin is a type 2 of ribosome-inactivating proteins isolated from some seeds significantly growing in Brazil. It is a potent agent to inhibit the protein synthesis in cancer cells and also HIV-infected cells. Pulchellin can be conjugated to HIV monoclonal antibodies to specifically target the HIV-infected cells. To analyze the protein synthesis inhibition by Pulchellin, the intracellular localization of the immunoconjugate should be compared to Pulchellin. In this case, the intracellular trafficking of this protein in cells can be determined by confocal microscopy. In our study, we utilized Pulchellin to construct HIV monoclonal antibody-conjugated Pulchellin A chain in order to target HIV-infected lymphocyte cells. Afterward the conjugation was labeled with the superior Alexa Fluor 488 dye. As a subsequent step, we are interested in studying the intracellular trafficking pathway of this novel conjugation in HIV-infected cells by confocal microscopy. Moreover, possible quantitative methods for fluorescent labeling of the immunoconjugate during confocal microscopy will be investigated.

We verified the changes promoted by ionizing radiation in bone tissue using FTIR. Samples of bovine bone were irradiated using Cobalt-60 with 0.01kGy, 0.1kGy, 1kGy, 15kGy and 75kGy. The effects of ionizing irradiation on chemical structure of bone, were studied considering the sub-bands of amide I, the crystallinity index and relation of organic and inorganic materials. ATR-FTIR spectroscopy showed changes in organic components and in hydroxyapatite crystals organization. High correlation with statistical significance was observed between (amideIII+collagen)/ ν1,ν3PO4, crystallinity and mechanical properties of the samples.

Objectives: to develop an apparatus for the detection of early caries lesions in enamel using the full extent of the tooth fluorescence spectrum, through the integration of a laser diode, fiber optics, filters and one portable spectrometer connected to a computer, all commercially available; to evaluate the developed device in clinical and laboratory tests, and compare its performance with commercial equipment. Methods: clinical examinations were performed in patients with indication for exodontics of premolars. After examinations, the patients underwent surgery and the teeth were stored individually. The optical measurements were repeated approximately two months after extraction, on the same sites previously examined, then histological analysis was carried out. Results: the spectral detector has presented high specificity and moderate sensitivity when applied to differentiate between healthy and damaged tissues, with no significant differences from the performance of the commercial equipment. The developed device is able to detect initial damages in enamel, with depth of approximately 300 μm. Conclusions: we successfully demonstrated the development of a simple and portable system based in laser-induced fluorescence for caries detection, assembled from common commercial parts. As the spectral detector acquires a complete recording of the spectrum from each tissue, it is possible to use it for monitoring developments of caries lesions.

Infrared radiation was employed to study the optical transmission properties of pigskin and the factors that influence transmission at room temperature. The skin samples from the forehead of piglets were irradiated using an infrared-pulsed source by varying the beam properties such as optical power, power density, duty cycle, as well as sample thickness. Because infrared radiation in select instances can penetrate through thick-fleshy skin more easily than visible radiation, temperature fluctuations observed within the skin samples stemming from exposure-dependent absorption revealed interesting transmission properties and the limits of optical exposure. Pigskin was selected for this study since its structure most closely resembles that of human skin. Furthermore, the pulsed beam technique compared to continuous operation offers more precise control of heat generation within the skin. Through this effort, the correlated pulsed-beam parameters that influence infrared transmission were identified and varied to minimize the internal absorption losses through the dermis layers. The two most significant parameters that reduce absorption losses were frequency and duty cycle of the pulsed beam. Using the Bouger-Beer-Lambert Law, the absorption coefficient from empirical data is approximated, while accepting that the absorption coefficient is neither uniform nor linear. Given that the optical source used in this study was single mode, the infrared spectra obtained from irradiated samples also reveal characteristics of the skin structure. Realization of appropriate sample conditions and exposure parameters that reduce light attenuation within the skin and sample degradation could give way to novel non-invasive measuring techniques for health monitoring purposes.

The effects of ageing and skin type on Photodynamic Therapy (PDT) for different treatment methods have been theoretically investigated. A multilayered Monte Carlo Radiation Transfer model is presented where both daylight activated PDT and conventional PDT are compared. It was found that light penetrates deeper through older skin with a lighter complexion, which translates into a deeper effective treatment depth. The effect of ageing was found to be larger for darker skin types. The investigation further strengthens the usage of daylight as a potential light source for PDT where effective treatment depths of about 2 mm can be achieved.

Cellular redox potential is important for the control and regulation of a vast number of processes occurring in cells. When the fine redox potential balance within cells is disturbed it can have serious consequences such as the initiation or progression of disease. It is thought that a redox gradient develops in cancer tumours where the peripheral regions are well oxygenated and internal regions, further from vascular blood supply, become starved of oxygen and hypoxic. This makes treatment of these areas more challenging as, for example, radiotherapy relies on the presence of oxygen. Currently techniques for quantitative analysis of redox gradients are limited. Surface enhanced Raman scattering (SERS) nanosensors (NS) have been used to detect redox potential in a quantitative manner in monolayer cultured cells with many advantages over other techniques. This technique has considerable potential for use in multicellular tumour spheroids (MTS) – a three dimensional (3D) cell model which better mimics the tumour environment and gradients that develop. MTS are a more realistic model of the in vivo cellular morphology and environment and are becoming an increasingly popular in vitro model, replacing traditional monolayer culture. Imaging techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM) and helium ion microscopy (HIM) were used to investigate differences in morphology and NS uptake in monolayer culture compared to MTS. After confirming NS uptake, the first SERS measurements revealing quantitative information on redox potential in MTS were performed.

Nonmelanoma skin cancers are the most common form of malignancy in humans. Between the traditional treatment ways, the photodynamic therapy (PDT) is a promising alternative which is minimally invasive and do not requires surgical intervention or exposure to ionizing radiation. The understanding of the cascade of effects playing role in PDT is not fully understood, so that define and understand the biochemical events caused by photodynamic effect will hopefully result in designing better PDT protocols. In this study we investigated the potential of the FTIR spectroscopy to assess the biochemical changes caused by photodynamic therapy after 10 and 20 days of treatment using 5-aminolevulinic acid (ALA) as precursor of the photosensitizer photoporphyrin IX (PpIX). The amplitude values of second derivative from vibrational modes obtained with FTIR spectroscopy showed similar behavior with the morphological features observed in histopathological analysis, which showed active lesions even 20 days after PDT. Thus, the technique has the potential to be used to complement the investigation of the main biochemical changes that photodynamic therapy promotes in tissue.

Raman spectroscopy has been applied to the analysis of biological samples for the last 12 years providing detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential use of this technology in cancer diagnosis has shown encouraging results for the in vivo, real-time and minimally invasive diagnosis. Confocal Raman technics has also been successfully applied in the analysis of skin aging process providing new insights in this field. In this paper it is presented the latest biomedical applications of Raman spectroscopy in our laboratory. It is shown that Raman spectroscopy (RS) has been used for biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis. This study aimed to improve the discrimination between different thyroid pathologies by Raman analysis. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. It will be also report the application of in vivo confocal Raman spectroscopy as an important sensor for detecting advanced glycation products (AGEs) on human skin.

Drugs used during anesthesia could enhance microvascular flow disturbance, not only for their systemic cardiovascular actions but also by a direct effect on the microcirculation and in particular on hemorheology. This is particularly important in high-risk surgical patients such as those with vascular disease (diabetes, hypertension, etc.). Therefore, in this work we propose a set of innovative parameters obtained by digital analysis of microscopic images to study the in vitro hemorheological effect of propofol and vecuronium on red blood cell from type 2 diabetic patients compared to healthy donors. Obtained innovative parameters allow quantifying alterations in erythrocyte aggregation, which can increase the in vivo risk of microcapillary obstruction.

Considering several clinical situations, low intensity laser therapy has been widely applied in pain relief or analgesia mechanism. With the advent of new LED-based (light emitting diode) light sources, the need of further clinical experiments aiming to compare the effectiveness among them is paramount. The LED system therapeutic use can be denominated as LEDT - Light Emitting Diode Therapy. This study proposed two clinical evaluations of pain relief effect: to dentin hypersensitivity and to cervicogenic headache using different sources of lasers (low and high intensity) and light emitting diodes (LEDs), one emitting at the spectral band of red (630+/- 5nm) and the other one at infrared band (880+/- 5nm). Two different clinical studies were performed and presented interesting results. Considering dentin hypersensitivity, red and infrared led were so effective than the control group (high intensity laser system); by the other side, considering cervicogenic headache, control group (infrared laser) was the best treatment in comparison to red and infrared led system.

In this work we investigate the scattering of light in means turbid in the presence or not of pigment and nanoparticles. For this we initially using a sample of collagen from means turbid with and without the presence of curcuma pigments and nanoparticles. Our results show that the light scattering is more intense in the samples with nanoparticles and curcuma pigment.

The experimental evaluated the photodynamic therapy (PDT) in wound healing. It used 60 male rats, making two circular wounds at each animal. They were treated at 48hs intervals, with methylene blue (MB), low level laser treatment (LLLT) or both, thus resulting in PDT. The wounds were observed 01, 03, 07, 14 and 21 days after and then processed and subjected to HE staining to analyze granulation tissue, necrosis, epithelialization and collagen. After day 1, wounds treated with MB showed necrosis less intense than other groups, and the PDT group showed more intense granulation tissue. At day 3, reepithelialization was absent for half of injuries in the PDT group, and this group was also with lower collagen. However, at day 7, this same group presented reepithelialization more advanced than control group, which did not happen with those treated with MB or LLLT (p = 0.015). The results allow us to conclude that PDT difficulted reepithelization at 7th day and interfered in standard healing. However, when used separately, MB and LLLT interfered significantly compared to the control group, which did not happened to the PDT group. There was no significant difference between the treatment groups in other analysed times.

Skin hydration is important to prevent aging and dysfunction of orofacial system. Nowadays, it is known that cutaneous system is linked to muscle system, then every dentist need to treat healthy facial skin, as lips, keeping orofacial functions healthy. Thirty-two patients were treated using laser and led therapy single or associated to biomaterials (dermo-cosmetics) searching for the best protocol to promote skin hydration. Using a peace of equipment to measure electric impedance, percentage of water and oil from skin, before and after different treatments were analyzed. Statistic tests using 5% and 0.1% of significance were applied and results showed that light could improve hydration of epidermis layer of facial skin. Considering just light effect, using infrared laser followed by blue led system is more effective to hydration than just blue led system application. Considering dermo-cosmetic and light, the association between both presented the best result.

Knowledge of dental structures is essential for understanding of laser interaction and its consequences during adhesion processes. Tubule density in dentin ranges from 4.900 to 90.000 per mm², for diameters from 1 to 3 μm. Light propagation inside the tubules is associated with tubules orientation. To the best of our knowledge, there is no previous work in literature characterizing physical-chemical alterations in dentin. The dentin samples were irradiated with a Er,Cr:YSGG Laser at wavelength 2.78 μm, with an energy density of 9.46 J/cm² , above the ablation threshold. ATRFTIR at wavenumbers 2000 to 700 cm^-1 was used to evaluate the differences among third root region and tubules orientation.

Blue LED system irradiation shows many important properties on skin as: bacterial decontamination, degradation of endogenous skin chromophores and biostimulation. In this clinical study we prove that the blue light improves the skin hydration. In the literature none authors reports this biological property on skin. Then this study aims to discuss the role of blue light in the skin hydration. Twenty patients were selected to this study with age between 25-35 years old and phototype I, II and III. A defined area from forearm was pre determined (A = 4.0 cm²). The study was randomized in two treatment groups using one blue light device (power of 5.3mW and irradiance of 10.8mW/cm²). The first treatment group was irradiated with 3J/cm² (277seconds) and the second with 6J/cm² (555 seconds). The skin hydration evaluations were done using a corneometer. The measurements were collected in 7, 14, 21 and 30 days, during the treatment. Statistical test of ANOVA, Tukey and T-Student were applied considering 5% of significance. In conclusion, both doses were able to improve the skin hydration; however, 6J/cm² has kept this hydration for 30 days.

Photodynamic therapy (PDT) is a treatment modality that can be indicated for several cancer types and pre-cancer lesions. One of the main applications of PDT is the treatment of superficial skin lesions such as basal cell carcinoma, Bowen’s disease and actinic keratosis. Three elements are necessary in PDT, a photosensitizer (PS); light at specific wavelength to be absorbed by the PS, and molecular oxygen. A typical PS used for skin lesion is protoporphyrin IX (PpIX), which is an intrinsic PS; its production is stimulated by a pro-drug, such as 5-aminolevulinic acid (ALA). Before starting a treatment, it is very important to follow up the PpIX production (to ensure that enough PS was produced prior to a PDT application) and, during a PDT session, to monitor its photodegradation (as it is evidence of the photodynamic effect taking place). The aim of this paper is to present a unique device, LINCE (MMOptics - São Carlos, Brazil), that brings together two probes that can, respectively, allow for fluorescence imaging and work as a light source for PDT treatment. The fluorescence probe of the system is optically based on 400 nm LED (light emitting diodes) arrays that allow observing the fluorescence emission over 450 nm. The PDT illumination probe options are constituted of 630 nm LED arrays for small areas and, for large areas, of both 630 nm and 450 nm LED arrays. Joining both functions at the same device makes PDT treatment simpler, properly monitorable and, hence, more clinically feasible. LINCE has been used in almost 1000 PDT treatments of superficial skin lesions in Brazil, with 88.4% of clearance of superficial BCC.

Image processing tools have been widely used in systems supporting medical diagnosis. The use of mobile devices for the diagnosis of melanoma can assist doctors and improve their diagnosis of a melanocytic lesion. This study proposes a method of image analysis for melanoma discrimination from other types of melanocytic lesions, such as regular and atypical nevi. The process is based on extracting features related with asymmetry and border irregularity. It were collected 104 images, from medical database of two years. The images were obtained with standard digital cameras without lighting and scale control. Metrics relating to the characteristics of shape, asymmetry and curvature of the contour were extracted from segmented images. Linear Discriminant Analysis was performed for dimensionality reduction and data visualization. Segmentation results showed good efficiency in the process, with approximately 88:5% accuracy. Validation results presents sensibility and specificity 85% and 70% for melanoma detection, respectively.

Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with excellent spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400–1,800 cm^-1) has been shown to be very promising for optical biopsy purposes. However, limitations to discrimination of dysplastic and inflammatory processes based on the fingerprint region still persist. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2,800–3,600 cm^-1) provides more specific information based on N-H, O-H and C-H vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the highwavenumber spectral region by collecting Raman spectra of nucleoli, nucleus and cytoplasm from oral epithelial cancer (SCC-4) and dysplastic (DOK) cell lines and from normal oral epithelial primary cells, in vitro, which were then analyzed by area under the curve as a method to discriminate the spectra. In this region, we will show the discriminatory potential of the CH vibrational modes of nucleic acids, proteins and lipids. This technique demonstrated more efficient discrimination than the fingerprint region when we compared the cell cultures.

Optical properties of the biological tissue play an important role to a correct use of optical techniques for therapy and diagnosis. The mice skin presents morphological differences due to characteristics such as gender, body mass and age. Murine models are frequently used in pre-clinical trials in optical therapy and diagnosis. Therefore, the assessment of the skin tissue in animal models is needed for a proper understanding of how light interacts with skin. Noninvasive techniques such as optical coherence tomography (OCT) have been used to obtain optical information of the tissue, as the attenuation coefficient, with the advantage of obtaining sectional images in real time. In this study, eight female BALB/c albino mice (twenty-four weeks old) and eight male C57BL/6 black mice (eight weeks old) were used to measure the attenuation coefficient of the light in the skin, utilizing the OCT technique, aiming to check for influence of the aging process. Two moments were assessed twenty-two weeks apart from each other. Our data show that the aging process significantly affects the light attenuation coefficient in mice skin. Twenty-two weeks after, statistical significant differences were observed between groups within a same strain. We conclude that light attenuation coefficient of mice skin may be influenced by factors such as disorganization of the dermis. Morphological aspects of skin should be taken into account in studies that involve optical strategies in murine models.

Vitamins A, E and C play important role in skin homeostasis and protection. Hence, they are extensively used in many cosmetic and cosmeceutic products. However, their molecules are unstable, and do not easily penetrate into the skin, which drastically decreases its efficiency in topical formulations. Liposoluble derivative of the vitamin A - retinyl palmitate, vitamin E - tocopheryl acetate, and vitamin C - tetraisopalmitoyl ascorbic acid, are more stable, and are frequently used as an active ingredient in cosmetic products. Moreover, increased hydrophobicity of these molecules could lead to a higher skin penetration. The aim of this work is to track and compare the absorption of the liposoluble derivatives of the vitamins and their encapsulated form, into the healthy human skin in vivo. We used Confocal Raman Spectroscopy (CRS) that is proven to be helpful in label-free non-destructive investigation of the biochemical composition and molecular conformational analysis of the biological samples. The measurements were performed in the volar forearm of the 10 healthy volunteers. Skin was treated with both products, and Raman spectra were obtained after 15 min, 3 hours, and 6 hours after applying the formulation. 3510 Skin Composition Analyzer (River Diagnostics, The Netherlands) with 785 nm laser excitation was used to acquire information in the fingerprint region. Significant difference in permeation of the products was observed. Whereas only free form of retinyl palmitate penetrate the skin within first 15 minutes, all three vitamin derivatives were present under the skin surface in case of nanoparticulated form.

Metastasis is one of the major cancer complications, since the malignant cells detach from the primary tumor and reaches other organs or tissues. The sentinel lymph node (SLN) is the first lymphatic structure to be affected by the malignant cells, but its location is still a great challenge for the medical team. This occurs due to the fact that the lymph nodes are located between the muscle fibers, making it visualization difficult. Seeking to aid the surgeon in the detection of the SLN, the present study aims to develop a widefield fluorescence imaging device using the indocyanine green as fluorescence marker. The system is basically composed of a 780nm illumination unit, optical components for 810nm fluorescence detection, two CCD cameras, a laptop, and dedicated software. The illumination unit has 16 diode lasers. A dichroic mirror and bandpass filters select and deliver the excitation light to the interrogated tissue, and select and deliver the fluorescence light to the camera. One camera is responsible for the acquisition of visible light and the other one for the acquisition of the ICG fluorescence. The software developed at the LabVIEW^® platform generates a real time merged image where it is possible to observe the fluorescence spots, related to the lymph nodes, superimposed at the image under white light. The system was tested in a mice model, and a first patient with tongue cancer was imaged. Both results showed the potential use of the presented fluorescence imaging system assembled for sentinel lymph node detection.

The raw cotton production requires multiple steps being one of them the removal of impurities acquired during previous processes. This procedure is widely used by textile industries around the world and is called bleaching. The raw cotton is composed by cellulosic and non-cellulosic materials like waxes, pectins and oils, which are responsible for its characteristic yellowish color. The bleaching process aims to remove the non-cellulosic materials concentration in the fabric, increasing its whiteness degree. The most used bleaching method utilizes a bath in an alkali solution of hydrogen peroxide, stabilizers and buffer solutions under high temperature. In the present study we evaluated the possibility of using a blue illumination for the bleaching process. We used blue LEDs (450 nm) to illuminate an acid hydrogen peroxide solution at room temperature. The samples treated by this method were compared with the conventional bleaching process through a colorimetric analysis and by a multiple comparison visual inspection by volunteers. The samples were also studied by a tensile test in order to verify the integrity of the cloth after bleaching. The results of fabric visual inspection and colorimetric analysis showed a small advantage for the sample treated by the standard method. The tensile test showed an increasing on the yield strength of the cloth after blue light bleaching. The presented method has great applicability potential due to the similar results compared to the standard method, with relative low cost and reduced production of chemical waste.

Biochemical composition of the skin changes in each layer and, therefore, the skin spectral profile vary with the depth. In this work, in vivo Confocal Raman spectroscopy studies were performed at different skin regions and depth profile (from the surface down to 10 μm) of the stratum corneum, to verify the variability and reproducibility of the intra- and interindividual Raman data. The Raman spectra were collected from seven healthy female study participants using a confocal Raman system from Rivers Diagnostic, with 785 nm excitation line and a CCD detector. Measurements were performed in the volar forearm region, at three different points at different depth, with the step of 2 μm. For each depth point, three spectra were acquired. Data analysis included the descriptive statistics (mean, standard deviation and residual) and Pearson's correlation coefficient calculation. Our results show that inter-individual variability is higher than intraindividual variability, and variability inside the SC is higher than on the skin surface. In all these cases we obtained r values, higher than 0.94, which correspond to high correlation between Raman spectra. It reinforces the possibility of the data reproducibility and direct comparison of in vivo results obtained with different study participants of the same age group and phototype.

The hypertrophy is known as an increase the cross-sectional area of the muscle as a result of a muscular work against an overload, and it is compensatory because the overload is induced by functional elimination of synergistic muscles. The importance of study the compensatory hypertrophy is understand how this process can be influenced by the irradiation with regard to the weight and muscle cross-sectional area, to assist in the rehabilitation process and the effectiveness functional return. The aim was evaluate the effects of low-level laser irradiation on morphological aspects of muscle tissue, comparing the weight and cross-sectional area in rat skeletal muscle. Wistar rats were divided into three groups: control, hypertrophy group without irradiation (right plantar muscle) and hypertrophy group and irradiation (left plantar muscle), both analyzed after 7 and 14 days. The irradiation was performed daily immediately after the surgery. The parameters were: λ = 780nm, beam spot of 0.04 cm2, output power of 40mW, power density of 1W/cm2, energy density of 10J / cm2 and 10s exposure time with a total energy of 3.2 J. The results revealed that low level laser irradiation an increase the weight of the plantaris muscle after 7 and 14 days with a difference of 7.06% and 11.51% respectively. In conclusion, low level laser irradiation has an effect on compensatory hypertrophy to produce increased muscle weight and promoted an increase in cross-sectional area of muscle fibers in the compensatory hypertrophy model after 14 days with parameters cited above.

Accumulation of AGEs [Advanced Glycation End – products] occurs slowly during the human aging process. However, its formation is accelerated in the presence of diabetes mellitus. In this paper, we perform a noninvasive analysis of glycation effect on human skin by in vivo confocal Raman spectroscopy. This technique uses a laser of 785 nm as excitation source and, by the inelastic scattering of light, it is possible to obtain information about the biochemical composition of the skin. Our aim in this work was to characterize the aging process resulting from the glycation process in a group of 10 Health Elderly Women (HEW) and 10 Diabetic Elderly Women (DEW). The Raman data were collected from the dermis at a depth of 70-130 microns. Through the theory of functional density (DFT) the bands positions of hydroxyproline, proline and AGEs (pentosidine and glucosepane) were calculated by using Gaussian 0.9 software. A molecular interpretation of changes in type I collagen was performed by the changes in the vibrational modes of the proline (P) and hydroxyproline (HP). The data analysis shows that the aging effects caused by glycation of proteins degrades type I collagen differently and leads to accelerated aging process.

The immediate dental implant placement in the molars region is critical, because of the high amount of bone loss and the discrepancy between the alveolar crest thickness and the dental implant platform. Laser phototherapy (LPT) improves bone repair thus could accelerate the implant placement. Twenty patients were selected for the study. Ten patients were submitted to LPT with GaAlAs diode laser (808nm) during molar extraction, immediately after, 24h, 48h, 72h, 96h and 7 days. The irradiations were applied in contact and punctual mode (100mW, 0.04cm2, 0.75J/cm2, 30s per point, 3J per point). The control group (n=10) received the same treatment; however with the power of the laser off. Forty days later samples of the tissue formed inside the sockets were obtained for further microtomography (microCTs) and histomorphometry analyses. Data were compared by the Student t test, whereas those from the different microCT parameters were compared by the Pearson correlation test (p<0.05). The relative bone volume, as well as area was significantly higher (p<0.001) in the lased than the control group. In the control group there were negative correlations between number and thickness, and between number and separation of trabecula (p<0.01). Between thickness and separation of trabecula the correlation was positive (p<0.01). The laser group showed significant negative correlation between the number and the thickness of trabecula (p<0.01). LPT accelerated bone repair. By the Pearson correlation test it was possible to infer that the lased group presented a more homogeneous trabecular configuration, which would allow earlier dental implant placement.

Considering the use of high intensity lasers for preventing dental caries, this blind in vitro study evaluated the compositional and fluorescence effects promoted by Nd:YAG laser (λ=1064 nm) when applied for prevention of progression of dentin caries, in association or not with topical application of acidulated phosphate fluoride (APF). Sixty bovine root dentin slabs were prepared and demineralized by 32h in order to create early caries lesions. After, the slabs were distributed into six experimental groups: G1- untreated and not submitted to a pH-cycling model; G2- untreated and submitted to a pH-cycling model; G3- acidulated phosphate fluoride application (APF); G4- Nd:YAG irradiation (84.9 J/cm2, 60 mJ/pulse); G5- treated with Nd:YAG+APF; G6- treated with APF+Nd:YAG. After treatments, the samples of groups G2 to G6 were submitted to a 4-day pH-cycling model in order to simulate the progression of early caries lesions. All samples were characterized by the micro-attenuated total reflection technique of Fourier transformed infrared spectroscopy (μATR-FTIR), using a diamond crystal, and by a fluorescence imaging system (FIS), in which it was used an illuminating system at λ= 405±30 nm. Demineralization promoted reduction in carbonate and phosphate contents, exposing the organic matter; as well, it was observed a significant reduction of fluorescence intensity. Nd:YAG laser promoted additional chemical changes, and increased the fluorescence intensity even with the development of caries lesions. It was concluded that the compositional changes promoted by Nd:YAG, when associated to APF, are responsible for the reduction of demineralization progression observed on root dentin.

Red blood cell aggregation is one of the most important factors in blood viscosity at stasis or at very low rates of flow. The basic structure of aggregates is a linear array of cell commonly termed as rouleaux. Enhanced or abnormal aggregation is seen in clinical conditions, such as diabetes and hypertension, producing alterations in the microcirculation, some of which can be analyzed through the characterization of aggregated cells. Frequently, image processing and analysis for the characterization of RBC aggregation were done manually or semi-automatically using interactive tools. We propose a system that processes images of RBC aggregation and automatically obtains the characterization and quantification of the different types of RBC aggregates. Present technique could be interesting to perform the adaptation as a routine used in hemorheological and Clinical Biochemistry Laboratories because this automatic method is rapid, efficient and economical, and at the same time independent of the user performing the analysis (repeatability of the analysis).

Cancer is responsible for about 13% of all causes of death in the world. Over 7 million people die annually of this disease. In most cases, the survival rates are greater when diagnosed in early stages. It is known that tumor lesions present a different temperature compared with the normal tissues. Some studies have been performed in an attempt to establish new diagnosis methods, targeting this temperature difference. In this study, we aim to investigate the use of a handheld thermographic camera to discriminate skin lesions. The patients presenting Basal Cell Carcinoma, Squamous Cell Carcinoma, Actinic Keratosis, Pigmented Seborrheic Keratosis, Melanoma or Intradermal Nevus lesions have been investigated at the Skin Departament of Amaral Carvalho Hospital. Patients are selected by a dermatologist, and the lesion images are recorded using an infrared camera. The images are evaluated taken into account the temperature level, and differences into lesion areas, borders, and between altered and normal skin. The present results show that thermography may be an important tool for aiding in the clinical diagnostics of superficial skin lesions.

The pharyngitis and laryngitis are respiratory tract infections highly common. Pharyngitis can be accompanied by fever, especially if caused by a systemic infection. Laryngitis is an inflammation of your voice box (larynx) from irritation or infection. The conventional treatment is the antibiotics administration, which may be responsible by an increase of identification of bacterial strains resistant to drug. This fact associated to high incidence of these infections become important to develop new technologies for diagnosis. This study aims to evaluate the use of widefield fluorescence imaging for the characterization of oropharynx infections, in order to diagnose the bacteria colonization. The imaging system for wide field fluorescence visualization is Evince^® (MMOptics, São Carlos, SP, Brazil) coupled to an Apple iPhone^® cell phone device. The system consists of Light Emitting Diodes (LEDs) operating in the violet blue region centered at green-red spectrum 450 nm and optical filters that allow viewing of fluorescence. A tongue depressor was adapted to Evince^® for mouth opening. The same images were captured with white light and fluorescence with an optical system. The red fluorescence may be a bacterial marker for physiological monitoring of oropharynx infection processes. The bacterial biofilm on tissue were assigned to the presence of protoporphyrin IX. This work indicates that the autofluorescence of the tissue may be used as a non-invasive technique to aid in the oropharynx infection diagnostic.

In the present study we report on the ability of gold nanoparticles (AuNP) to enhance the antimicrobial activity of the photosensitizer Rose Bengal (RB), a very effective singlet oxygen generator. Our experiments were conducted using a suspension of Escherichia Coli in the presence of either RB or a combination of RB and AuNP. Nanoparticles were synthesized by laser ablation in water, which allows high purity, biologically friendly AuNP production, as compared to traditional chemical methods. Several relative concentrations of bacteria, photosensitizes and AuNP were studied. Bacterial survival rates were determined before and after LED light illumination. The phototoxicity of RB with and without AuNP was checked following illumination for 10 and 20 minutes. As a control, the dark toxicity of RB was verified. The results show that the survival rate of bacteria decreases significantly with the increase of RB concentration and illumination time, which is in accordance with previous works. Interestingly, our results also indicate a significant increase in the lethal photosensitization of RB in the presence of AuNP. We propose this effect is due to plasmonic light enhancement, considering the superposition of RB and AuNP absorption spectra, which favors electric field enhancement effects in the presence of AuNP. Similar experiments using the photosensitizer Methylene Blue (MB) allowed us to test our hypothesis for MB did not show any difference in its phototoxicity in the presence of AuNP. We propose this observed synergistic effect could be an effective way for improving photodynamic inactivation of microorganisms.

Liposomes have been used to deliver DNA, drugs and, more recently, nanoparticles such as quantum dots, into living cells. Their electrostatic interaction with cell’s surface (negatively charged) can lead to membrane destabilization and/or fusion, facilitating intracellular release of those compounds. Nevertheless, cationic lipids can modify living cells homeostasis, depending on their concentration. In this study, we observed that the DOTAP cationic lipid concentrations influence the red blood cells (RBCs) homeostasis. We used fluorescent fusogenic liposomes composed by three lipids: DOPE, DOTAP and DPPE-Rhodamine (1:0.1/0.3/0.5/0.8/1:0.1 mM respectively), varying DOTAP from 0.1 to 1 mM. To probe liposomes ability to fuse with cells, RBCs (1% in saline) were utilized. Liposomes were characterized by zeta potential, dynamic light scattering (DLS), fluorescence and transmission electron microscopy. Their interaction with RBCs was evaluated by fluorescence microscopy and flow cytometry. Zeta potential results showed that, from 0.1 to 1 mM concentration, the charge increases, due to the addition of DOTAP. Liposomes’ diameter does not vary significantly when more DOTAP was added, except for the one containing 0.1 mM of DOTAP, according to DLS results. Flow cytometry and microscopy analysis showed that for all DOTAP’ concentration applied, the liposomes were capable to label RBCs. However, as higher the amount of DOTAP in liposomes, the more harmful they were to cells. Thus, the results showed that it is possible to use lower concentrations of DOTAP keeping the fusogenic liposomes’s ability and cell homeostasis. This is important to guarantee a greater efficiency in the delivery of nanoparticles or other active samples into cells.

The aim of this study was to assess the effect in the enamel demineralization of low-intensity infrared laser (λ=810 nm, 100 mW/cm², 90 sec, 4.47 J/cm², 9 J) with or without photodynamic cream fluorinated or not fluorinated, using Optical Coherence Tomography (OCT). Background data: Lasers can be used as tools for the prevention of tooth enamel demineralization.

All enamel specimens (n= 105) were analyzed using OCT at baseline, and randomly assigned into seven groups (n=15): C (+), laser application; C(-), no treatment; (F), acid fluoride gel; cream (IV); cream and neutral fluoride (IVF); cream and laser (IVL); and cream with neutral fluoride+ laser (IVFL). The specimens were submitted to all kind of treatments before demineralizing pH cycling challenge and were reanalyzed.

ANOVA and Tukey's multiple comparative analysis (p <0.01) demonstrated a greater delta attenuation between baseline and post challenge for C + (0.034 ± 0.011) compared to IVF (0.016 ± 0.007) F (0.018 ± 0.010) IVFL (0.019 ± 0.008), and IVL (0.014 ± 0.010). The cream laser group (IVL) also showed lower delta (0.014 ± 0.010) compared to C - (0.025 ± 0.008).

The OCT technique demonstrated that cream associated with laser showed the lowest quantitative enamel mineral looses after cariogenic challenge.

New biomaterials such as multi-walled carbon nanotubes oxide/graphene oxide (MWCNTO/GO), nanohydroxyapatite (nHAp) and combination of them together or not to acidulated phosphate fluoride gel (F) have been tested as protective coating before root dentin erosion. Fourteen bovine teeth were cleaned, polished, divided into two parts (n=28) and assigned to seven groups: (Control) – without previous surface treatment; F treatment; nHAp; MWCNTO/GO; F+nHAp; F+MWCNTO/GO and F+MWCNTO/GO/nHAp composites. Each sample had two sites of pre-treatments: acid etched area and an area without treatment. After the biomaterials application, the samples were submitted to six cycles (demineralization: orange juice, 10 min; remineralization: artificial saliva, 1 h). Micro energy-dispersive X-ray fluorescence spectrometry (μ-EDXRF) mapping area analyses were performed after erosive cycling on both sites (n=84). μ-EDXRF mappings showed that artificial saliva and MWCNTO/GO/nHAp/F composite treatments produced lower dentin demineralization than in the other groups. Exposed dentin tubules allowed better interaction of nanobiomaterials than in smear layer covered dentin. Association of fluoride with other biomaterials had a positive influence on acid etched dentin. MWCNTO/GO/nHAp/F composite treatment resulted in levels of demineralization similar to the control group.

The fluorescence spectra and fluorescence lifetime analysis in biological tissues has been presented as a technique of a great potential for tissue characterization for diagnostic purposes. The objective of this study is to assemble and characterize a fluorescence lifetime spectroscopy system for diagnostic of clinically similar skin lesions in vivo. The fluorescence lifetime measurements were performed using the Time Correlated Single Photon Counting (Becker & Hickl, Berlin, Germany) technique. Two lasers, one emitting at 378 nm and another at 445 nm, are used for excitation with 20, 50 and 80 MHz repetition rate. A bifurcated optical fiber probe conducts the excitation light to the sample, the collected light is transmitted through bandpass filters and delivered to a hybrid photomultiplier tube detector. The fluorescence spectra were obtained by using a portable spectrometer (Ocean Optics USB-2000-FLG) with the same excitation sources. An instrument response function of about 300 ps was obtained and the spectrum and fluorescence lifetime of a standard fluorescent molecule (Rhodamine 6G) was measured for the calibration of the system ((4.1 ± 0.3) ns). The assembled system was considered robust, well calibrated and will be used for clinical measurements of skin lesions.

In laser cut clinical applications, the use of energy densities lower than the ablation threshold causes increase of temperature of the irradiated tissue, which might result in an irreversible thermal damage. Hence, knowing the ablation threshold is crucial for insuring the safety of these procedures. The aim of this study was to determine the ablation threshold of the Er,Cr:YSGG laser in bone tissue. Bone pieces from jaws of New Zealand rabbits were cut as blocks of 5 mm × 8 mm and polished with sandpaper. The Er,Cr:YSGG laser used in this study had wavelength of 2780 nm, 20 Hz of frequency, and the irradiation condition was chosen so as to simulate the irradiation during a surgical procedure. The laser irradiation was performed with 12 different values of laser energy densities, between 3 J/cm² and 42 J/cm², during 3 seconds, resulting in the overlap of 60 pulses. This process was repeated in each sample, for all laser energy densities. After irradiation, the samples were analyzed by scanning electron microscope (SEM), and it was measured the crater diameter for each energy density. By fitting a curve that related the ablation threshold with the energy density and the corresponding diameter of ablation crater, it was possible to determine the ablation threshold. The results showed that the ablation threshold of the Er,Cr:YSGG in bone tissue was 1.95±0.42 J/cm².

Resin composites are widely used as restorative materials due to their excellent aesthetical and mechanical properties. Posterior teeth are constantly submitted to occlusal stress and upon restoration require more resistant resins. The aim of this study was to analyze in vitro the wear suffered over time by restorations in resin composite in posterior teeth, by Optical Coherence Tomography (OCT). 30 molars had occlusal cavities prepared and were randomly divided into three groups (n=10) and restored with resin composite: G1: Filtek P90 (3M/ESPE), G2: Tetric N-Ceram (Ivoclar Vivadent); G3: Filtek P60 (3M/ESPE). Specimens were subjected to initial analysis by OCT (OCP930SR, Thorlabs, axial resolution 6.2 μm) and stereoscopic microscope. Specimens were submitted to thermocycling (500 cycles, 5-55 °C) and subjected to simulated wear through a machine chewing movements (Wear Machine WM001), projecting four years of use. After mechanical cycles, the specimens were submitted to a second evaluation by the OCT and stereoscopic microscopy. As a result, it was observed that 90% of the restorations of both groups had fractures and/or points of stress concentration, considered niches for early dissemination of new fracture lines. It was also found that G1 and G2 had more points of stress concentration, whereas G3 had a higher incidence of fracture lines already propagated. It was concluded that the G3 showed more brittle behavior at the masticatory wear when compared to G1 and G2.

Optical images have been used in several medical situations to improve diagnosis of lesions or to monitor treatments. However, most systems employ expensive scientific (CCD or CMOS) cameras and need computers to display and save the images, usually resulting in a high final cost for the system. Additionally, this sort of apparatus operation usually becomes more complex, requiring more and more specialized technical knowledge from the operator. Currently, the number of people using smartphone-like devices with built-in high quality cameras is increasing, which might allow using such devices as an efficient, lower cost, portable imaging system for medical applications. Thus, we aim to develop methods of adaptation of those devices to optical medical imaging techniques, such as fluorescence. Particularly, smartphones covers were adapted to connect a smartphone-like device to widefield fluorescence imaging systems. These systems were used to detect lesions in different tissues, such as cervix and mouth/throat mucosa, and to monitor ALA-induced protoporphyrin-IX formation for photodynamic treatment of Cervical Intraepithelial Neoplasia. This approach may contribute significantly to low-cost, portable and simple clinical optical imaging collection.

The in situ study evaluated antihistamine (DA) and bronchodilator(DB) drugs actions on dental enamel using FT Raman spectroscopy.

Analysis of pH drugs were permorfed, DA 1.48 and DB 2.90. Enamel (n=24) were analysed by FT - Raman and randomly distributed in control group (CG) and experimental groups (GEA and GEB), specimens fixed in palatine appliances. In CG, dripped 20% sucrose (8Xday/3 min)/7 days. In GEA, 20% sucrose (8Xday/3 min) + drug (4Xday/3 min). In GEB, 20% sucrose (8Xday/3 min) B + drug (4Xday/3 min). FT- Raman analysis was performed again. Data analyzed by Student t test and ANOVA

Differences in peak intensity of carbonate (CO₃) /phosphate (PO₄) (p<0.0286) post challenge in GEB related to baseline. The GEB integrated area of inorganic post challenge (p<0.0349).Organic loss in GEA, area (p<0.0228) and intensity (p<0. 0471) between moments and in GEB, area (p<0.0243) and intensity (p<0.00276). Comparing organic area and intensity difference observed post challenge GC (0,31±0,13) and GEB(0,54±0,13). Area difference between GEA(0,30±0,16) X GEB(0,54±0,13) and intensity difference GC(0,09172±0,04) and GEB(0,16±0,04) and GEA(0,091±0,05) X GEB(0,16±0,04). Significant integrated area CO₃/PO₄ loss for GC(0,12±0,01)X GEB(0,16±0,02) and GEB X GEA(0,13±0,02). For intensity differences were observed between GC(0,08±0,01) and GEB(0,10±0,01), and the last one and GEA(0,08±0,01)

After administration of drugs, reduction in the amount of carbonate, organic and inorganic components were observed, denoting possible demineralization.

The bone fracture is important public health problems. The lasertherapy is used to accelerate tissue healing. Regarding diagnosis, few methods are validated to follow the evolution of bone microarchitecture. The aim of this study was to evaluate the effects of lasertherapy on bone repair with x-ray microtomography (μCT) and histomorphometry. A transverse rat tibia osteotomy with a Kirchner wire and a 2mm width polymeric spacer beads were used to produce a delayed bone union. Twelve rats were divided into two groups: (i) Control Group: untreated fracture and; (ii) Laser Group: fracture treated with laser. Twelve sessions of treatment (808nm laser, 100mW, 125J/cm², 50seconds) were performed. The μCT scanner parameters were: 100kV, 100μA, Al+Cu filter and 9.92μm resolution. A volume of interest (VOI) was chosen with 300 sections above and below the central region of the fracture, totaling 601sections with a 5.96mm. The softwares CT-Analyzer, NRecon and Mimics were used for 2D and 3D analysis. A histomorphometry analysis was also performed. The connectivity (Conn) showed significant increase for Laser Group than Control Group (32371±20689 vs 17216±9467, p<0.05). There was no significant difference for bone volume (59±19mm3 vs 47± 8mm³) and histomorfometric data [Laser and Control Groups showed greater amount of cartilaginous (0.19±0.05% vs 0.11±0.09%) and fibrotic (0.21±0.12% vs 0.09±0.11%) tissues]. The negative effect was presence of the cartilaginous and fibrotic tissues which may be related to the Kirchner wire and the non-absorption of the polymeric that may have influenced negatively the light distribution through the bone. However, the positive effect was greater bone connectivity, indicating improvement in bone microarchitecture.

Optical Coherence Tomography (OCT) is a noninvasive technique capable of generating in vivo high-resolution images. However, OCT images are degraded by a granular and random noise called speckle. Nevertheless, such a noise may be used to gather information regarding the sample, as is exploited by techniques like Speckle Variance – OCT (SV-OCT). SV-OCT is widely used in the literature, but the variance calculation is computationally expensive. Therefore, we propose a new algorithm to employ speckle in identifying flow based on the evaluation of intensity fluctuation between two consecutively acquired OCT images. Our results were compared to those obtained by traditional method of Speckle Variance to demonstrate the feasibility of the technique. Both algorithms were applied to series of OCT images from a microchannel flow phantom, as well as from a biological tissue with blood flow. The results obtained by our method are in good agreement with those from SV-OCT. We've also analyzed the performance of both algorithms, registering the processing time and memory use. Our method performed 31% faster with the same use of memory. Therefore, we demonstrated a new method to map flow on OCT images.

Optical Coherence Tomography (OCT) is a noninvasive imaging technique with high resolution widely used for in vivo applications. Nonetheless, OCT is prone to speckle, a granular noise that degrades the OCT signal. Speckle statistics may, nevertheless, reveal information regarding the scatterers from which it originates. This fact is exploited by techniques such as Speckle Variance-OCT (SVOCT). SVOCT, however, doesn’t provide quantitative information, which is a major drawback for the use of speckle based techniques on OCT. In the present work we attack this problem, proposing a new method for analysis of speckle in OCT signal, based on autocorrelation. We associate the changes in decorrelation time of the signal with the changes in flow velocity. It is expected that greater velocities result in lower decorrelation times. To verify that, milk was pumped through a microchannel at different velocities, and the decorrelation time was computed for a single point in the center of the microchannel, sampled at 8 kHz rate. Our results suggest that for flows rates greater than 1 μl/min it is possible to associate decorrelation time with flow velocity, while velocities below that value are not distinguishable, supposedly due to the Brownian motion. For flow rates above 50 μl/min our acquisition rate doesn’t get enough sampling information, as the decorrelation time gets too low. These results indicate that Speckle based techniques may be used to get quantitative information of flow in OCT samples, which can be used to assist in many diagnostics modalities, as well as map such flow regions.

This paper aims to research about the effects of radiating a sample containing the platelet population of the human blood system (ages ranging 18 to 35 years) with low power lasers (wavelengths 632 nm and 532 nm) for a given time. The proposed methodology consists on exposing samples to both radiations. Two more samples, a male and a female, are not exposed, thus working as control groups and allowing quantitative comparisons with the exposed samples. The results showed that after radiating for 30 minutes with the green laser (532 nm), the platelet population from the male sample increased 0.5% while the one from the female sample increased 4.5%; after radiating for 60 minutes, the male sample showed an increase of 3.5% and the female 1.4%. After radiating with the red laser (632 nm) for 30 minutes, the male sample revealed an increase of 7.9%; after radiating for 60 minutes, the male sample presented an increase of 0.7 and the female 5.5%. In conclusion, the experiments demonstrated that 532 nm and 632 nm laser radiation increase platelet numbers in human blood cells.

Imaging methods are widely used in diagnostic and among the diversity of modalities, optical coherence tomography (OCT) is nowadays commercially available and considered the most innovative technique used for imaging applications, in both medical and non-medical applications. In this study, we exploit the OCT technique in the oral cavity for identification and differentiation between free and attached gingiva, as well as determining the gingival phenotype, an important factor to determination of periodontal prognosis in patients. For the animal studies, five porcine jaws were analyzed using a Swept Source SS-OCT system operating at 1325nm and stereomicroscope, as gold pattern. The SSOCT at 1325nm was chosen due to the longer central wavelength, that allows to deeper penetration imaging, and the faster image acquisition, an essential factor for clinical setting. For the patient studies, a total of 30 males and female were examined using the SS-OCT at 1325nm and computer controlled periodontal probing. 2D and 3D images of tooth/gingiva interface were performed, and quantitative measurements of the gingival sulcus could be noninvasively obtained. Through the image analysis of the animals jaws, it was possible to quantify the free gingiva and the attached gingiva, the calculus deposition over teeth surface and also the subgingival calculus. For the patient’s studies, we demonstrated that the gingival phenotype could be measured without the periodontal probe introduction at the gingival sulcus, confirming that OCT can be potentially useful in clinic for direct observation and quantification of gingival phenotype in a non-invasive approach.

Burn healing is a process to repair thermally damaged tissues. Although burn healing has many aspects, it is common for dynamics of collagen fiber, such as decomposition, production, or growth, to be closely related with burn healing. If such healing process can be visualized from the viewpoint of the collagen dynamics, one may obtain new findings regarding biological repairing mechanisms in the healing process. To this end, second-harmonic-generation (SHG) light will be an effective optical probe because of high selectivity and good image contrast to collagen molecules as well as high spatial resolution, optical three-dimensional (3D) sectioning, minimal invasiveness, deep penetration, the absence of interference from background light, and in situ measurement without additional staining. Furthermore, since SHG light arises from a non-centrosymmetric triple helix of three polypeptide chains in the collagen molecule, its intensity decreases and finally disappears when thermal denaturation caused by the skin burn changes the structure of this molecule to a centrosymmetric random coil. Therefore, optical assessment of skin burn has been investigated by SHG microscopy. In this paper, we applied SHG microscopy for in situ imaging of the healing process in animal skin burn and successfully visualized the decomposition, production, and growth of renewal collagen fibers as a series of time-lapse images in the same subject.

Liver transplantation is a well-established treatment for liver failure. However, the success of the transplantation procedure depends on liver graft conditions. The tissue function evaluation during the several transplantation stages is relevant, in particular during the organ harvesting, when a decision is made concerning the viability of the graft. Optical fluorescence spectroscopy is a good option because it is a noninvasive and fast technique. A partial normothermic hepatic ischemia was performed in rat livers, with a vascular occlusion of both median and left lateral lobes, allowing circulation only for the right lateral lobe and the caudate lobe. Fluorescence spectra under excitation at 532 nm (doubled frequency Nd:YAG laser) were collected using a portable spectrometer (USB2000, Ocean Optics, USA). The fluorescence emission was collected before vascular occlusion, after ischemia, and 24 hours after reperfusion. A morphometric histology analysis was performed as the gold standard evaluation ─ liver samples were analyzed, and the percentage of necrotic tissue was obtained. The results showed that changes in the fluorescence emission after ischemia can be correlated with the amount of necrosis evaluated by a morphometric analysis, the Pearson correlation coefficient of the generated model was 0.90 and the root mean square error was around 20%. In this context, the laser-induced fluorescence spectroscopy technique after normothermic ischemia showed to be a fast and efficient method to differentiate ischemic injury from viable tissues.

Traditional techniques to evaluate the aggregation of red blood cells by optical methods require large sample volume and provide parameters that vary significantly from one method to another. A simplified variant of a chip system previously developed by Shin et al. (2009)¹ based on light transmission for measuring erythrocyte aggregation is presented. Through a detailed analysis of intensity versus time curves, relevant information about erythrocyte aggregation and its variables is obtained. Parameters that provide more accuracy for the diagnosis of patients in order to have an immediate application in Clinical Medicine are proposed.

The use of portable electronic devices, in particular mobile phones such as smartphones is increasing not only for all known applications, but also for diagnosis of diseases and monitoring treatments like topical Photodynamic Therapy. The aim of the study is to evaluate the production of the photosensitizer Protoporphyrin IX (PpIX) after topical application of a cream containing methyl aminolevulinate (MAL) in the cervix with diagnosis of Cervical Intraepithelial Neoplasia (CIN) through the fluorescence images captured after one and three hours and compare the images using two devices (a Sony Xperia^® mobile and an Apple Ipod^®. Was observed an increasing fluorescence intensity of the cervix three hours after cream application, in both portable electronic devices. However, because was used a specific program for the treatment of images using the Ipod^® device, these images presented better resolution than observed by the Sony cell phone without a specific program. One hour after cream application presented a more selective fluorescence than the group of three hours. In conclusion, the use of portable devices to obtain images of PpIX fluorescence shown to be an effective tool and is necessary the improvement of programs for achievement of better results.

The atheromatous plaques exhibit an accumulation of protoporphyrin IX, or PpIX, which is transferred to the feces. In this work it was associated a precursor of the PpIX, the 5-aminolevulinic acid, ALA, with gold nanoparticles (ALA:AuNps). The objective was verify the possibility to use ALA:AuNPs as a diagnosis agent for atherosclerosis. ALA:AuNps were synthesized mixing ALA with Tetrachloroauric(III) acid in miliQ water solution followed by photoreduction with light from a Xenon lamp. A total of 22 Male New Zealand rabbits were divided into 3 groups: control group (CG) where animals received normal diet, control group with ALA (CGALA ) and Experimental Group with ALA:AuNPs ( EGALAAu ) in which the animals received a diet with 1% cholesterol. Measurements of the emission intensity of extracted porphyrins from the feces in the region between 575 and 725 nm were done. An increase in the feces porphyrin emission after ALA and ALA:AuNPs administration was observed.

Diffuse reflectance spectroscopy (DRS) is a rapid, non-invasive optical method widely adopted to gain diagnostic information of tissue. The most flexible approach to this method is a fiber-optic contact-probe used with a spectroscopy system. A challenge of this method is that the external pressure brought by the probe can significantly affect the tissue optical properties as well as the light coupling into the probe, and thus influence the collected DRS-spectrum. In this study we investigate and characterize the effect of probe pressure on DRS-spectra obtained with a calibrated loaded-spring system used with a fiber optic probe in the range (400 − 1600) nm. A multilayer FE-model of the indentation is developed to get a better insight of the distribution of pressure and stresses inside the skin under indentation.

Euglenoids are a group of predominantly free-living unicellular microorganisms that mostly live in freshwater bodies but can also be found in marine and brackish waters. These organisms have a characteristic that distinguishes them form the other protists: they are covered by a surface pellicle formed by S-shaped overlapping bands which resemble a diffraction grating. These microorganisms have developed numerous protection mechanisms intended to avoid or reduce the damage produced by UV radiation, such as the production of pigments and the repair mechanisms in hours of darkness and during daylight. In a recent paper we have investigated the role played by the pellicle of Euglenoids in the protection of the cell against UV radiation, by means of an electromagnetic approach based on the approximation of the pellicle profile by a one-dimensional diffraction grating. This simplified model allowed us to confirm that under certain incidence conditions, the corrugation of the pellicle helps increase the UV reflection, and consequently, diminish the UV radiation that enters the cell. In order to analyze the electromagnetic response of the whole cell, we extend two different approaches to calculate the reflected response: a simulation method especially developed to deal with complex biological structures that permits the introduction of the scattering object via an electron microscopy image, and the integral method, which has been widely used to compute the electromagnetic response of finite structures. Numerical results of near and far fields are shown.

pathology. The optical properties of these intrinsic fluorophores respond to the microenvironment and the metabolic status, thus making fluorescence spectroscopy a valuable tool to study the conditions of biological tissues. The purpose of this study is to investigate the hairless mice skin metabolic changes during the photoaging process through lifetime and fluorescence measurements targeting NADH and FAD. Two lasers centered at 378 nm and 445 nm, respectively, perform excitation of NADH and FAD. The fluorescence acquisition is carried out at mice dorsal and ventral regions throughout the photoaging protocol and aging process. Differences in fluorescence and lifetime data between young and photoaged mice measurements were observed. The endogenous fluorescence spectrum of photoaged dorsal skin showed an increase compared to young and aged skin. Lifetime of bound NADH and free FAD presented an increase in the first week that continued until the end of the protocol. Aging process is being investigated to complement the information obtained from fluorescence data and lifetime of photoaging process.

OCT has been used to evaluate dental materials, and is employed here to evaluate lumineers for the first time. Lumineers are used as esthetical indirect restoration, and after wearing and aging, several undesirable features such as gaps, bubbles and mismatch can appear in which would only be seen by invasive analysis. The OCT (spectral domain SD-OCT, 930nm central wavelength) was used to evaluate noninvasively the lumineer- cement-tooth interface. We analyzed 20 specimens of lumineers-teeth that were prepared in bovine teeth and randomly allocated in 4 experimental groups (n=5) with two different cementation techniques and two different types of cementing agent (RelyX U200 and RelyX Veneer, 3M ESPE, with the adhesive recommended by the manufacture). The lumineers were made of lithium disilicate and obtained using a vacuum injection technique. The analysis was performed by using 2D and 3D OCT images, obtained before and after cementing and the thermal cycling process to simulate thermal stress in a oral cavity. Initial measurements showed that the SD-OCT was able to see through the 500μm thick lumineer, as delivered by the fabricant, and internal stress was observed. Failures were found in the cementing process and also after ageing simulation by thermal cycling. The adhesive failures as bubbles, gaps and degradation of the cementation line are the natural precursors of other defects reported by several studies of clinical follow-up (detachments, fractures and cracks). Bubble dimensions ranging from 146 μm to 1427 μm were measured and the OCT was validated as an investigative and precise tool for evaluation of the lumineer-cement-tooth.

The use of light as a therapeutic agent has been the subject of several studies; however, the dosimetry for its clinical application is still based on empirical data. The propagation of light in biological tissues depends on the tissue optical properties, and these properties may vary among people, tissues and sites, making it diffcult to establish dosimetry. In this context, the research for methods to determine the spatial distribution of light in individual biological tissues becomes essential, allowing the individual dosimetry. This study aims to image the diffuse reflectance at the optical phantom surface to infer the spatial distribution of light inside a phantom when an absorbing obstacle is present. Red laser were used as light source on solid turbid optical phantom; a small black sphere was used as absorbing obstacle. It is important to know, in real time and in a non-invasive way, about the existence of heterogeneities that may compromise the light propagation inside a biological tissue, so that the light dosimetry might be properly established.

A portable microscope/microendoscope will be presented in this article. The system was specially designed for Smartphones and taking into account its simplicity, will be able to bring this technology to almost every doctor’s office. It is worth mentioning its flexibility of use, that allows several modes since all the components are interchangeable (the illumination LED, the lens, the optic filters, etc) resulting in different applications, from medical applications until other areas (for example, the inspection of non-accessible pieces of plane engines). In addition, the system has a double platform, working as a conventional microscope or as a fiberoptic microendoscope. In situ and cell smear interrogation of oral mucosa, using a proflavine as dye will be presented. The price of the system does not exceed US$ 350, plus the price of the fiber bundle (around US$ 500) turning it onto a high resolution affordable system.

Onychomycosis is a common disease of the nail plate, constituting approximately half of all cases of nail infection. Onychomycosis diagnosis is challenging because it is hard to distinguish from other diseases of the nail lamina such as psoriasis, lichen ruber or eczematous nails. The existing methods of diagnostics so far consist of clinical and laboratory analysis, such as: Direct Mycological examination and culture, PCR and histopathology with PAS staining. However, they all share certain disadvantages in terms of sensitivity and specificity, time delay, or cost.

This study aimed to evaluate the use of infrared and fluorescence imaging as new non-invasive diagnostic tools in patients with suspected onychomycosis, and compare them with established techniques.

For fluorescence analysis, a Clinical Evince (MM Optics^®) was used, which consists of an optical assembly with UV LED light source wavelength 400 nm ± 10 nm and the maximum light intensity: 40 mW/cm² ± 20%. For infrared analysis, a Fluke^® Camera FKL model Ti400 was used. Patients with onychomycosis and control group were analyzed for comparison. The fluorescence images were processed using MATLAB^® routines, and infrared images were analyzed using the SmartView^® 3.6 software analysis provided by the company Fluke^®.

The results demonstrated that both infrared and fluorescence could be complementary to diagnose different types of onychomycosis lesions. The simplicity of operation, quick response and non-invasive assessment of the nail patients in real time, are important factors to be consider for an implementation.

The use of gold nanoparticles (AuNps) as the vehicle for 5-Aminolevulinic acid (ALA) delivery for photodynamic and photothermic plasmonic therapies is a promising approach, especially with the recent demonstration that this photosensitizer immobilization on the particle surface improves reactive oxygen species (ROS) formation, increasing its cytotoxicity. Gold nanorods (AuNRs) present an absorption spectrum shifted to 700 nm, within the tissue transparency window, which allows excitation of the nanoparticles situated deeper in the tissues. Here, we describe a new synthesis method that was applied to control the shape of the gold nanoparticles during its synthesis. To obtain ALA:AuNRs, precursor ALA:AuNps were irradiated by ultrashort laser pulses. The variation of the laser parameters such as pulse energy and duration and irradiation time was assessed. The relevant mechanisms are discussed.

The first Brazilian standard for UV protection sunglasses, NBR15111, was drafted and published in 2003, hitherto a faithful copy (mirror) of European, BSEN1836 standard. From 2010 to 2013 the Laboratório de Instrumentação Oftálmica of the School of Engineering of São Carlos (USP) made contribution in the review and drafting of this standard and the main change so far is on the extension of the UV range analysis for protection of sunglasses, i.e. from 280 - 380nm to 280-400nm. In previous studies, there are indications that ultraviolet protection degrades with use and exposure of sunglasses to natural ultraviolet radiation. Thus, this project aims to build a prototype for irradiating sunglasses lenses, where one of the spectacles will be submitted to the solar simulator; and the other to the prototype. This prototype consists of a panel with cover, which houses 100 lenses arranged in the vertical (user’s) position and which will be irradiated by the sun from sunrise until sunset. The lid opens automatically and should turn towards the sun, so that the lens will always be irradiated facing the sun. Sensors will be installed to close the cover and protect the lenses of undesirable weather conditions and to determine the ultraviolet index to which the lenses are being subjected to. The exposure time and UV index will be recorded and automatic opening or closing the lid may also be interfered by a PC by online software. Previously to irradiation, spectroscopy will be performed and then repeated after every 30 days of exposure.

Diffuse reflectance spectroscopy (DRS) with a fiber-optic contact probe is a cost-effective, rapid, and non-invasive optical method used to extract diagnosis information of tissue. By combining commercially available VIS- and NIR-spectrometers with various fiber-optic contact-probes, we have access to the full wavelength range from around 400 to 1600 nm. Using this flexible and portable spectroscopy system, we have acquired ex-vivo DRS-spectra from murine, porcine, and human liver tissue. For extracting the tissue optical properties from the measured spectra, we have employed and compared predictions from two models for light propagation in tissue, diffusion theory model (DT) and Monte Carlo simulations (MC).

The focus in this work is on the capacity of this DRS-technique in discriminating metastatic tumor tissue from normal liver tissue as well as in assessing and characterizing damage to non-malignant liver tissue induced by preoperative chemotherapy for colorectal liver metastases.

Background: Laser speckle contrast imaging allows non-invasive assessment of cutaneous blood flow. Although the technique is attractive to measure a quantity related to the skin blood flow (SBF) in anesthetized animal models, movements from breathing can mask the SBF signal. As a consequence, the measurement is overestimated because a variable amount of a DC component due to the breathing movements is added to the SBF signal. Objective: To evaluate a method for estimating the background level of the SBF signal, rejecting artefacts from breathing. Methods: A baseline correction method used for accurate DNA sequencing was evaluated, based on estimating the background level of a signal in small temporal sliding-windows. The method was applied to evaluate a mouse model of hindlimb ischemia. SBF signals from hindlimbs of anesthetized C57BL/6 mice (n=13) were registered. The mean SBF (Fi and Fc from ischemic and control hindlimbs) were computed from the registers and from the corresponding estimated background levels (Fib and Fcb from ischemic and control hindlimbs). Results: The mean values of the percentages (a measure of ischemia) MI = (Fi/Fc).100 and MIb = (Fib/Fcb).100 were computed to be 30±4% and 23±3% respectively (mean ± SE). Evidences of statistical differences between both, ischemic and control hindlimbs, were obtained (p<0.05, paired student-t). The mean error [(MI-MIb)/MIb].100 obtained was 45±14% (mean±SE). Conclusion: The recovery of a corrupted SBF signal by breathing artefacts is feasible, allowing more accurate measurements.

Granular phosphors are commonly used in several applications in biomedical imaging and instrumentation. The structural and optical properties of phosphor materials affect the optical signal transferred out and play a critical role in the quality of the final signal or image. In recent years, following developments in materials science and technology, several new methods have been successfully implemented for the preparation of nanosized phosphors. It is of interest to investigate whether nanophosphors could replace existing micro phosphors for next generation high-performance displays and imaging devices. The purpose of the present study was to investigate the variation of the optical parameters (e.g. light extinction coefficient m_ext, probability of light absorption p, light anisotropy factor g) in the sub-micron and nano scale under the variability of light wavelength (400-700 nm) and refractive index (e.g., two limiting values were used 1.4 and 2.0). For the case of low refractive index (1.4), by increasing the grain diameter: (a) the light extinction increases, (b) the light absorption probability decreases and (c) the anisotropy factor increases in the whole range or gran sizes (2-1000 nm). However, for the high value of the refractive index (2.0), the light extinction coefficient was found to increase up to a maximum for grain diameter: (a) 200 nm (at 400 nm light wavelength) and (b) 600 nm (at 700 nm light wavelength). Finally, at 400 nm grain diameter, the probability of light absorption was found to decrease down to a minimum while the anisotropy factor was found to increase up to maximum for all light wavelengths considered.