This PDF file contains the front matter associated with SPIE Proceedings Volume 10877 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Pleiotropic and evolutionally conserved components of transcription nuclear factor - NF-B play key roles in progression of various diseases by regulating expression of antiapoptotic and cytokine responsive genes [1] [2]. We previously demonstrated that rapidly activating transcription factors (TF) can be detected by using sequence-specific self-quenched reporter probes (oligonucleotide-molecular sensors (ODN-MS), which ideally remain “silent” in the absence of activated TF but emit photons upon specific binding to them [3-5]. Recently we were investigating sensor-based optical imaging of early inflammation in the endocrine pancreas using type 1 diabetes (T1D) model because NF-κB activation is essential for determining the fate of pancreatic β-cells and hence the progression of T1D. Using an immunocompetent SKH1 mouse model of early stage T1D we showed that NF-κB activation was induced by low-dose streptozotocin (LD-STZ). ODNMS probes that carried near-infrared (NIR) fluorophores formed a complex with NF-κB subunits in in vitro assays and in situ after LD-STZ treatment. Imaging studies of pancreas (sections and isolated islets) were corroborated with electrophoresis mobility shift assays (EMSA). A higher specific NIR fluorescence intensity in nuclei and cytoplasm of islets from LD-STZ treated groups compared to non-treated control animals was observed. Our results demonstrate that: 1) the use of ODN-MS probes in non-fixed islets and tissue sections may be used for distinguishing differences in inflammatory pathway activation in animal models of early stage diabetes; 2) early, non-invasive detection of NF-κB in pancreatic islets may serve as a potential strategy for imaging of early T1D-mediated sustained pro-inflammatory changes in the endocrine pancreas.

There has been increasing interest both for fundamental research and clinical applications in using laser speckle contrast imaging to image flow. Laser speckle contrast imaging utilizes intrinsic tissue contrast from dynamic light scattering. It provides a rather simple way of imaging, for example, blood flow and its spatial and temporal variations. In this report we will try to extend the capabilities of speckle contrast imaging by using longer excitation wavelength in order to increase the imaging depth and to provide additional contrast imaging enhanced by resonance optical absorption.

We present an alternative approach for using dynamic laser speckle data to quantify biophysical dynamics including ordered flows and random motions. The approach yields images that superficially resemble traditional laser speckle contrast images, but instead of relying on the statistics of the local time integrated intensity values calculated over temporal and sliding spatial windows as is done in LSCI to create images, ellipticity imaging (EI) directly yields images that quantify the relative dominance of long-range correlations in the temporal dimension of a series of speckle patterns to the short-range correlations in the same dimension. The approach relies on a Poincaré analysis of the speckle data which yields metrics that statistically describe both the short-terms variations in the temporal speckle intensity (i.e., the standard deviation in successive differences) and also the corresponding long term variations. These metrics are plotted against each other (Poincaré plots) and an ellipse fit to the data. The ratio of the semi-major axis to the semi-minor axis of this ellipse for each temporal speckle sequence is then used as the data to form the images (thus the term EI). The results of flow phantom and mouse EI studies will be presented. Various flow rates of dilute intralipid were illuminated with a coherent laser source and EI images were generated. The same speckle data were analyzed using spatial and temporal LSCI approaches. Flows in anesthetized mouse brain vessels were analyzed using EI and LSCI approaches. The results of the studies using the different speckle analyses will be discussed.

Laser speckle contrast imaging (LSCI) has been widely used in monitoring blood flow in brain, skin, and retina etc with the advantages of being a wide field imaging modality of high spatial and temporal resolution, useful in investigating functional activities of tissues, exploring mechanisms of diseases, and evaluating drug efficiency. Despite its wide applications and long history, however, there is no systematic study and recommended recipes to obtain absolute flow velocity from LSCI measurement, in particular, when the accuracy of the current LSCI of flow is compounded by static scattering and measurement noise. In this presentation, we analyzed laser speckle flow imaging from the first principle and provided a complete procedure covering the LSCI system calibration, static scattering removal, and measurement noise estimation and removal to obtain a genuine flow speckle contrast and the flow speed. We demonstrated the power of our recommended LSCI analysis recipes by imaging Intralipid-2% suspension moving at varying speeds. Experimental results show that our recipe greatly enhances the linear sensitivity of the flow index (defined as the inverse decorrelation time) and the linearity covers the full span of flow speeds from 0mm/s to 40mm/s. The determination of the flow speed is also not affected by the overlying static scattering layers. Our proposed LSCI analysis procedure hence paves the way to estimate the true flow speed in applications.

We present and validate a forward model for modeling light propagation in brain tissue. The model is a dynamic light scattering Monte Carlo simulation that tracks the dynamic scattering events of a photon through a brain tissue geometry. We use the simulation to create a simulated laser speckle contrast image, and compare the simulated image with experimental images.

A novel non-invasive, wearable VCSEL-based system for multipoint in − vivo measurements of blood perfusion was introduced. The system operates on the basis of the laser Doppler flowmetry (LDF) method and allows for microcirculation studies. The sensors developed were used to analyse the skin blood flow synchronization in homologous regions of the contralateral limbs, both in the basal state and during various functional tests. A high synchronisation of blood flow rhythms in the contralateral limbs of healthy volunteers was shown in the studies presented.

Blood flow imaging is an essential part of biomedical research, particularly in the vascular and neurovascular physiology. It includes various imaging modalities, with laser speckle contrast imaging (LSCI) being one of the most extensively used tools for the rapid wide-field flow characterization. For years, the capability of LSCI to become a quantitative tool has been discussed. Being based on the contrast relation to the speckle correlation time, the method requires a robust model and its correct parametrization. Main uncertainties are (i) light scattering and particle motion regimes which define the form of the field autocorrelation function g1 and (ii) static scattering and speckle averaging effects on the intensity correlation function g2. Multi-exposure laser speckle contrast imaging and proper system calibration can solve the later issue, but in order to evaluate g1 form, one has to directly measure speckle autocorrelation. We introduce the dynamic laser speckle imaging (DLSI) as a new step in the wide-field speckle dynamics analysis. By utilizing a high-speed camera and recording backscattered light at more than 20000 frames per second we are able to measure the temporal intensity correlation (g2) in the mice cortex. We demonstrate that DLSI data can be used to estimate all parameters of the speckle autocorrelation model. By finding the best fit model for each pixel, we show that all three types of known g1 models can be found in the cortex and that the best fit model depends on the vessel size. Furthermore, we explore the commonly used model for the blood flow index and explain its deviations from the actual flow speed. We show that DLSI can be used to calibrate LSCI, thus solving contrast imaging problems and providing a lightweight quantitative tool for the blood flow imaging.

Crop yields are frequently affected by the vigor of seeds. Although germination tests and vigor tests are performed on sampled seeds to ensure the quality of seeds, selection of crops is based on the appearance or physical properties of roots and shoots of seedlings. Monitoring of the biological activities of seed by biospeckle Optical Coherence Tomography (OCT) was proposed for the selection of seeds. Biospeckle OCT used speckle contrast, which is defined by the ratio of standard deviation to mean value, of the temporal fluctuation of OCT intensities to indicate the biological activities of seeds. Seeds of pea were germinated for the experiment. As a comparison of the level of biological activities, some seeds were boiled to terminate the biological activities. Multiple OCT scans at the same positions on the seeds were obtained for the analysis of biospeckle. The speckle contrast was calculated for each pixel of OCT intensities at each measurement. Increased speckle contrast was observed in the seeds even before the radicle emerged. Low speckle contrast was observed in the boiled seeds. As a conclusion, the speckle contrast of OCT intensities indicated biological activities of seeds in the process of germination. It has the potential to indicate if a seed is dead or alive in an early stage of germination for the purpose of seed selection.Crop yields are frequently affected by the vigor of seeds. Although germination tests and vigor tests are performed on sampled seeds to ensure the quality of seeds, selection of crops is based on the appearance or physical properties of roots and shoots of seedlings. Monitoring of the biological activities of seed by biospeckle Optical Coherence Tomography (OCT) was proposed for the selection of seeds. Biospeckle OCT used speckle contrast, which is defined by the ratio of standard deviation to mean value, of the temporal fluctuation of OCT intensities to indicate the biological activities of seeds. Seeds of pea were germinated for the experiment. As a comparison of the level of biological activities, some seeds were boiled to terminate the biological activities. Multiple OCT scans at the same positions on the seeds were obtained for the analysis of biospeckle. The speckle contrast was calculated for each pixel of OCT intensities at each measurement. Increased speckle contrast was observed in the seeds even before the radicle emerged. Low speckle contrast was observed in the boiled seeds. As a conclusion, the speckle contrast of OCT intensities indicated biological activities of seeds in the process of germination. It has the potential to indicate if a seed is dead or alive in an early stage of germination for the purpose of seed selection.

Leukocyte-endothelial interactions have been well-characterized by intravital microscopy in mice. Quantitative parameters descriptive of these dynamic processes, e.g. the level of leukocyte rolling, adhesion and extravasation, can detect and track inflammation. Despite technology available to study individual cell motion noninvasively in human skin, we are not aware of any published exploratory or clinical studies. In this preliminary study, we explore the feasibility to extract parameters characteristic of individual cell motion in the postcapillary vessels of healthy human skin from videos taken by a noninvasive clinical confocal microscope (Vivascope 1500). The microscope is capable of real-time imaging of individual cells at 9 frames per second. We took videos of ten cutaneous vessels per each of two body sites (volar forearm and upper anterior chest) of ten healthy subjects. We then characterized the dynamic motion of cells via subsequent video analysis by extracting the following parameters: blood flow velocity, number of adherent leukocytes (stationary <30 s), and number and diameter of vessels. We observed variation in blood flow velocity within 1 minute in the same vessel, between vessels within an 8x8 mm field of view, and within two different body sites. Leukocyte adhesion, more commonly associated with inflammatory conditions, can also be observed in healthy skin. Further studies are needed to test the potential of this approach to detect inflammation.

In the current report, further developments of a biophysically-based optical model of human skin and a novel method for real-time realistic simulation of human skin are presented. The model utilizes voxelized representation of the tissue and considers spatial/volumetric variations in both structural e.g. surface roughness and chromophore concentration changes in skin layers such as distribution of blood, melanin, collagen, index of blood oxygen saturation, water, pigment content, etc. A Monte-Carlo based approach for simulation of spatially-varying Bidirectional Scattering-Surface Reflectance Distribution Function (BSSRDF) and subsequent physically based computer rendering has been developed. Computer modelling is accelerated by parallel computing on Graphics Processing Units (GPUs) using OpenCL (Open Computing Language). The results of simulation of BSSRDFs, reflectance spectra of human tissues, corresponding colours and 3D rendering examples of human skin appearance are presented and compared with in vivo experimental data obtained during clinical studies.

Receptor-targeting has been considered a method of choice for drug delivery in oncology because many types of cancer have elevated expression of a specific receptor. Recently, our group has demonstrated that quantification of interacting receptors, particularly homo-dimers, can be achieved in vivo using lifetime-based Förster Resonance Energy Transfer (FRET). However, quantification of FRET is typically performed in microscopy by either intensity- or lifetime-based measurement. Herein, we report on cross-validation between intensity and lifetime-based FRET for in vivo applications. In particular, we demonstrated dynamic in vivo FRET quantification using both intensity and lifetime measurements for assessing transferrin receptor engagement in live intact animals. Using hybridized oligonucleotides as FRET standard, we obtained the same FRET quantification via both intensity and lifetime-based measurements. Overall, both measurement methods provided the same FRET quantification trends of receptor engagement over 120 minutes of imaging. However, intensity FRET approach required 18 measurements (17 of which were used for calibration), whereas lifetime FRET required only one measurement. Hence, macroscopic fluorescence lifetime FRET presents superior, more rapid and simple method for the assessment of targeted drug delivery in longitudinal preclinical studies.

In mammals, the oviduct is where a new life initializes with a series of reproductive events taking place, including gametes transport, fertilization, and embryo transfer. A disruption of any of these processes could lead to reproductive disorders, such as infertility. However, a significant lack of the knowledge in the dynamic aspect of these processes have left the etiology of these disorders poorly understood, limiting the efficiency and effectiveness of corresponding clinical management. Although dynamic assessment of the reproductive events in the mammalian oviduct is greatly desired, available imaging techniques are largely restricted with in vitro and ex vivo conditions, not suitable to pursue the tissue and cell dynamics due to the absent of native bioenvironment. Here, we present an in vivo imaging approach capable to probe the mouse oviduct and the reproductive processes inside in a high-resolution, 3D, dynamic, functional, and quantitative fashion. Optical coherence tomography (OCT) is combined with a dorsal imaging window to achieve imaging access to the whole oviduct. With volumetric OCT imaging, we report the detailed structure of the oviduct, sub-cellular visualization of the oocytes, zygotes, and preimplantation embryos, as well as their dynamic movements. Through developing functional OCT imaging methods, we demonstrate micro-scale mapping of the oviductal cilia beat frequency, enable 3D tracking of the sperm, and obtain interesting sperm behaviors at the fertilization site. These results indicate the OCT-based imaging approach can be a useful tool for mammalian reproduction research and will ultimately lead to new discoveries in the field of reproductive biology.

A comprehensive understanding about the dynamics of time-dependent, photoinduced physiological processes affecting the spectral attributes and, consequently, the appearance of human tissues is essential for new advances in biology, medicine, biomedical photonics and computer graphics, just to name a few fields that can benefit from it. Skin is arguably the most investigated of these complex biological systems. Its interactions with light have been the object of extensive studies aimed at a wide range of applications, from the detection and treatment of diseases to the synthesis of realistic images for educational and entertainment purposes. However, the dynamics of photoinduced physiological processes leading to skin appearance changes over time remains an open research topic. In this paper, we address the effects of tanning, one of the most prominent and persistent photobiological phenomena leading to such appearance changes. More specifically, we present a novel physiologically-based framework for the simulation of skin tanning dynamics, and describe how it can be employed in the visualization of the tanning-induced variations on skin’s spectral attributes. Its first-principles algorithms explicitly account for the connections between spectrally-dependent light stimuli and time-dependent physiological reactions occurring within the cutaneous tissues. This enables the effective simulation of these tissues’ main mechanisms of adaptation to ultraviolet radiation. As a result, nonlinear skin appearance changes elicited by distinct light exposure regimes can be correctly reproduced. We demonstrate the predictive capabilities of the proposed framework through quantitative and qualitative comparisons of its outcomes with measurements and experimental observations reported in the literature. We believe that it provides a high-fidelity testbed for interdisciplinary research involving time-dependent skin responses to light exposure.

Patients with spinal cord injuries (SCI) are often subject to continues stationary pressure on prominent bony areas which, over and extended period of time, become high risk regions for pressure ulcers. Pressure ulcers are as prevalent as 30% in those with SCI and are one of the leading causes of re-hospitalization. In order to develop a better understanding of the methods of treating and preventing these pressure ulcers, we have developed a voxilization based model of the ischial tuberosity based on a Monte Carlo framework. The 3D model of the underside of the pelvis, the ischial tuberosity, allows for variation of the layers of the skin, fat, and muscle created in Solidworks. From the 3D model, the simulation was done with Monte Carlo eXtreme, a GPU-based Monte Carlo model. Tissue layer changes due to movement of the muscle and compression when sitting which results in a significant reduction of the muscle thickness have been accounted for in our model. Skin and muscle profusion of SCI patients is not well known and limited experimental work has been conducted in this environment. This model can aid in the study of methods of improving and maintaining skin health and help with rehabilitation and prevention of pressure ulcers.

The problem of extracting useful information for medical diagnosis from 2D and 3D optical imaging experimental data is of great importance. We are discussing challenges and perspectives of medical diagnosis using machine learning analysis of NIR and THz tissue imaging. The peculiarities of tissue optical clearing for tissue imaging in NIR and THz spectral ranges aiming the improvement of content data analysis, methods of extracting of informative features from experimental data and creating of prognostic models for medical diagnosis using machine learning methods are discussed.

Fine needle aspiration biopsy technique and following histological examination show its effectiveness and safety but its performing takes several time. However, the problem of real-time analysis of pathological changes in tissues remains relevant. We demonstrate optical fine-needle biopsy method, combining a fine needle (17.5G) and a fiber-optic probe (1 mm diameter) for minimally invasive interrogation of tissue in vivo. During rat tumor experiment, we collected spectrally-resolved diffuse reflectance and fluorescence. Quantified differences between tumor and normal tissues were demonstrated and approved with morphological analysis. The proposed methodology seems promising for developing new diagnostic criteria for clinical practice.

Video plethysmography (vPPG) is a noninvasive, remote diagnostics method that monitors cardiac activity by measuring subtle variations in the optical properties of skin driven by heart pulsations. However, the origin of the fluctuations in skin color at the heart rate responsible for the vPPG signal is not well understood. Using optical coherence tomography (OCT), we show evidence that the optical attenuation coefficient of the outermost layer of the epidermis is modulated at heart rate, being the modulation surrogate for the mechanical changes in the skin. We propose a hydraulic shock hypothesis to explain the phenomenon. The mechanical modulation of the non-vascularized epidermis would explain the modulation of optical properties of superficial skin, allowing for detection of pulsation even for non-penetrating radiation wavelengths such as blue light, as it is often observed.

Obesity is a pandemic affecting more than 93 million adults in the U.S. Obese are defined as individuals with a Body Mass Index (BMI) of 30 or more. Several studies are demonstrating that this weight-to-height ratio does not fully characterize the patient’s pathophysiology. Monitoring muscle metabolism, the synthesis and breakdown of muscle protein, may be a more useful metric in the characterization of pathologies associated to weight gain. Long term imbalances of energy intake to energy expenditures lead to obesity. Total expenditure is the summation of energies related to the thermic effect of food, activity, and resting expenditure. While at rest, muscle metabolism is the primary component of resting energy expenditure.Daily energy release in muscle mass could significantly lead a net-loss of fat in the long-run, and thus potentially contribute to the prevention of obesity. Near Infrared Spectroscopy (NIRS) measurement of muscle oxygenation can be used to study muscle metabolism. NIRS has the advantage of being a non-invasive, reproducible, and inexpensive methodology. Unfortunately, commercial NIRS system fail to produce accurate results in the obese population due to excess adipose thicknesses (AT) that alter the optical signal. We have used Monte Carlo models of light transfer to probe the optimal source-detector separation necessary to use NIRS in the obese. We have also developed a low-cost wearable muscle oximeter targeted to individuals with high BMI. We will demonstrate our system validation in optical phantoms and volunteers.

Second-harmonic generation (SHG) microscopy as a label-free imaging technique to study structure and function of cell and tissue has been gaining much interest and popularity. As with fluorescence microscopy techniques, there is a growing demand for enhancing spatial resolution of SHG microscopy to see more details. Considering the contrast mechanism of SHG microscopy, we extend the subtractive imaging method to SHG microscopy to enhance the spatial resolution and contrast. This method is based on the intensity difference between two images obtained with circularly polarized Gaussian and doughnut-shaped beams, respectively. By characterizing the intensity and polarization distributions of the two focused beams, we verify the feasibility of the subtractive imaging method in polarization dependent SHG microscopy. The resolution and contrast enhancement in different biological samples is demonstrated. A 1.3-fold resolution improvement is achieved and a significant contrast enhancement is obtained without any prior information of samples. And we demonstrate the possibility of further enhancement of spatial resolution and contrast using a partial aperture illumination strategy. The presented method can be easily adapted to other nonlinear microscopies, and will facilitate non-invasive in vivo imaging in biomedical studies.

In vivo monitoring cerebral and cutaneous hemodynamics is of great important to investigate brain and peripheral circulation system functional responses to physiopathologic stimulations. Nevertheless, the high scattering characteristics of skull and skin severely limit optical imaging performance. Fortunately, in vivo tissue optical clearing techniques can efficiently overcome these problem. In this work, we combined hyperspectral imaging (HSI) and laser speckle contrast imaging (LSCI) to simultaneously monitor the changes in cortical and cutaneous microvascular blood oxygen saturation and blood flow under assistance of in vivo skull and skin optical clearing techniques, and quantitatively compared the difference between cerebral and cutaneous arteriovenous functional responses when the hypoxic stimulations was performed. The results show that the cerebral arteriovenous blood flow response is much more sensitive to the hypoxic stimulations comparing with that of cutaneous vessels. As for the arteriovenous blood oxygen response, there are only small differences between cerebral and cutaneous vessels to the instant hypoxia, but the blood oxygen level of cerebral vessels recovers faster than that of cutaneous vessels after the hypoxic stimulation. This work provides a feasible solution to realize visualization of in vivo monitoring cerebral and cutaneous microvascular reactivity with minimal invasiveness. Monitoring of microvascular reactivity with high resolution is of great significance to the study of vascular dysfunction in some peripheral vascular and cerebrovascular diseases.

Tissue optical clearing technique plays an important role in three-dimensional (3D) visualization of intact organs or rodent bodies. As a typical organic-solvent based clearing method, 3DISCO renders the turbid tissues transparent by the strategy of minimizing light scattering, and possesses the advantages of high transparency and substantial size reduction, which could facilitate imaging of large-volume tissues. However, for heme-rich tissues, such as spleen, liver, embryo and clinical biopsy samples, tissue transparency and image quality by 3DISCO are limited due to the strong absorption ability of hemes. To address this problem, we proposed an optimized clearing method by introducing decolorization to modify the original 3DISCO protocol. The results showed that the optimized protocol could enhance the transparency of the heme-rich tissues and facilitate high-resolution imaging inside these tissues combining with optical microscopies.

Based on the changed leisure behavior, that means on the fact that vacationers spend their free time more and more in the mountains or in sunny regions by the sea, the use of sunscreen is of particular importance. The effectiveness of sunscreens against harmful UV radiation from the sun is characterized by the sun protection factor (SPF). For its determination, the minimum erythema dose, i.e. the dose of UV radiation causing sunburn in case of unprotected skin and sunscreen-treated skin is used. Thereby a sunburn is generated, which actually should be prevented by the sunscreen. This method is therefore unsatisfactory. The American Food and Drug Administration and the European Commission have been calling for the development of a non-invasive method for the determination of sun protection factors of sunscreens for years. At the Charité, a physical, non-invasive method for the determination of sunscreens was developed in cooperation with Courage Khazaka GmbH and Hans Karrer GmbH. The measuring method used here is based on the so-called "photon banana". UV radiation is applied to the sunscreen-treated skin through an optical fiber. Parts of the light are reflected, other parts are scattered in the tissue and emerge elsewhere. This light passes "banana-shaped" through the upper skin layer and passes through the sunscreen twice. It is detected with optical fibers and a detector. The excitation occurs using LEDs. Very good correlations between the measured SPF values and the SPF values determined in the test laboratories under in vivo conditions could be achieved.

Polarization imaging is a promising technique for probing the microstructures of tissues. Among the available polarimetric techniques, Mueller matrix polarimetry has many distinctive advantages, such as providing label-free and comprehensive descriptions on the properties of biomedical specimens. Recently, for pathological detections we developed a modulus designed Mueller matrix microscope by adding both the polarization states generator (PSG) and analyzer (PSA) to a commercial transmission light microscope. Some preliminary applications on various human cancerous tissues showed that the Mueller matrix microscope can be used to detect the abnormal areas of unstained tissue slices quantitatively. However, whether these parameters are still effective or not for backscattering imaging such as the Mueller matrix endoscope should be analyzed. It is crucial for the future in situ detections using Mueller matrix polarimetry. In this study, we compare these Mueller matrix parameters using the porcine liver tissue samples with appropriate thickness, which can be measured in both transmission and backscattering configurations. The retardancerelated and depolarization-related Mueller matrix imaging parameters between forward and backward imaging results are compared. For a more detailed analysis, we also calculate the indices of polarimetric purity for the depolarizationrelated parameters. The experimental results demonstrate that the retardance-related Mueller matrix parameters have distinct contrasts to characterize the anisotropic and isotropic structures of tissues. However, the contrast mechanisms of the depolarization-related parameters for different tissues still need more studies to confirm.

Anisotropic structures such as collagen, elastic, and muscle fibers are prevalent in biological tissues. Obtaining the orientation distribution information of these anisotropic structures is important in various biomedical applications. Recently, it is found that polarization imaging, especially Mueller matrix polarimetry can bring abundant microscopic information of complex samples. Previous studies demonstrated that the anisotropic properties in tissues may originate from both scattering or birefringence, which can hardly be distinguished clearly. In this study, we use the Mueller matrix polar decomposition (MMPD) and Mueller matrix transformation (MMT) parameters to obtain the accurate orientations of both the anisotropic scatterers and birefringence of turbid media in backscattering measurement. The experimental results of tissue phantoms and Monte Carlo simulations suggest that the MMT and MMPD parameters have the ability to distinguish the orientations of cylindrical scatterers and birefringence in a complex medium. The preliminary application on bovine tendon tissue samples with and without external force also demonstrates that the Mueller matrix derived parameters can be used to reveal the accurate anisotropy orientations in biological tissues. Moreover, to better understand the relationship between the anisotropy orientations and the Mueller matrix derived parameters, we also analyze the transmission Mueller matrix images of phantoms consisting of wave plates with different axis orientations. The results indicate that the anisotropy orientations information can be clearly revealed using the Mueller matrix derived parameters and may be helpful for future biomedical studies or diagnosis.

The study offers a possibility to use such biocompatible chemical as glycerol as a biomarker for early diagnostics of diabetes mellitus complications, in particular, for assessing the degree of myocardial lesion evidence by the stage of skin glycation during diabetes development and treatment. The study was aimed to find the difference in glycerol permeability through rat soft tissues of control and diabetic groups in order to show the possibility of glycerol usage as a biomarker of diabetes impact on different organs. The investigation presents transition the experimental studies from ex vivo to in vivo conditions.

The present work demonstrates the visualization of the intracellular distribution of upconversion nanoparticles (UCNPs) by microscopy with excitation in the NIR spectral range and detection of upconversion luminescence in the VIS range. The cell viability is scored for cytotoxic effects of UCNPs at dark and light exposed conditions. Non-functionalized UCNPs incubated with the cells are found to be endocytosed by cells. The obtained results confirm a high sensitivity of the luminescent UCNPs to the concentration variations within cells. UCNPs are promising alternatives to traditional fluorescent labels for cell imaging and possess prominent potentials in biological and clinical applications.

The study of blood microcirculation is one of the most important problems of the medicine. This is caused by the fact that many diseases, such as cardio-vascular diseases, atherosclerosis, diabetes, chronic venous insufficiency, oncology diseases, cause functional and morphological changes of microcirculation of blood flow. The results of experimental study of changes of blood microcirculation of pancreas in rats with diabetes measured by using Laser Speckle Contrast Imaging (LSCI) at application of optical clearing agents are presented. Laser speckle contrast techniques are based on the spatial and temporal statistics of the speckle pattern, calculating of contrast of time-averaged dynamic speckles in dependence on the exposure time at the registration of the speckle-modulated images. In research, 28 Wistar rats weighing 300-500 g were used. Alloxan induced animal model of diabetes was explored. The influence of solution of glycerol, PEG-300 was investigated. Application of 70%-aqueous glycerol solution demonstrates 50%-decrease of blood flow velocity in the group of diabetic animals, to 10th min blood flow velocity was completely restored. Blood flow in the control group almost stopped, to 10 min has not recovered. Application of solution of PEG-300 demonstrates 25%- decrease of blood flow in the group of diabetic animals. Blood flow in the control group show 65%-decrease of blood flow. The results obtained at the study of blood microcirculation disorders of pancreas in diabetes show that diseases development in animals causes changes in the microcirculatory system and application of optical clearing agents demonstrates changes in vascular permeability in conditions of development of pathologies.

The ability to recognize certain oscillatory patterns in human EEGs associated with various types of movements is studied on the basis of multiresolution analysis, which uses discrete wavelet-transform with Daubechies functions. It is shown that the dispersion of wavelet-coefficients at distinct levels of resolution enables to distinguish the background electrical activity of the brain, the movement of the arms/legs and the imaginations of different types of movements. The advantage of using wavelets with larger support for improving the quality of recognition is discussed.

We discuss entrainment phenomena in the regulation of cerebral and peripheral blood flow in newborn rats under normal conditions and during pathological changes in the dynamics of blood vessels accompanying the development of stroke. Using a wavelet-based coherence measure, we analyze the degree of interrelation between the dynamics of blood flow in the sagittal sinus, the surrounding network of small vessels, as well as in the artery and vein of the neck. We show that the coherence measure reflects changes in the entrainment at the latent stage of stroke formation.

Core body temperature (CT) is a key indicator of an individual’s risk for heat stroke in the field. Multi-parameter sensors are impractical for field testing as they require long data-collection periods and a wide variety of settings. In the simple near-infrared (NIR) imaging method proposed below, 940-nm light emitting diodes are used for NIR illumination. Continuous images are collected by a video camera and the region of interest is extracted from the video file to calculate the changes in mean intensity over the duration of the video. Increases in vein diameter due to heat stress on the dorsal part of the hand can be quantified with these NIR-illuminated videos. A simple NIR optical imaging system for dorsal vein diameter measurements was tested for its effectiveness in monitoring core temperature changes. The technique for measuring the vein diameter is described in detail. Typically, NIR imaging can be used to measure heart rate and vein patterns, but vein diameter can also be used to infer core temperature. A model was trained using data from five volunteers engaged in a two hour long laboratory exercise, in air temperatures 24–36°C, and with CTs ranging from 36– 40°C. The data was collected from ten participants including various combinations of temperature and clothing. Classifications with the model returned an R² value of 0.897 and root-mean-square error of 0.7428. Though the model for estimating CT cannot serve as a replacement for direct measurement of CT, the results suggest that it is accurate enough for providing practical monitoring of thermal strain in the work place.