Recently introduced horizontal attenuated total reflectance (HATR) Fourier transform infrared (FTIR) spectroscopy for real-time assessment and continuous monitoring of glucose biomolecules in the skin tissue directly on the patients might appear a promising alternative to interpret the activity of interstitial glucose metabolism in vivo by means of evaluating the dynamics of changes of glucose concentrations in interstitial fluid (IF). In the present study, in vivo spectra by ATR-FTIR spectroscopy were obtained post-prandially during a 120–180-minute continuous monitoring in three patients with type 2 diabetes and compared to pre-prandial spectra. In all patients with diabetes interstitial glucose levels at 1030 and 1041cm-1 reflected the best relationship with blood glucose. The lag time (LT) required for glucose to diffuse from the capillary to epidermal skin tissue was calculated between 0 and 60 minutes at all measured glucose biomolecules. Data showed intra- and inter-subject variations of each glucose biomolecule, pointing to similarities and differences among interstitial glucose metabolism of the patients. Finally, the findings suggest that HATR-FTIR spectroscopy might have the potential for clinical interpretation of activity of glucose metabolism for diagnosis, management, and treatment of patients with diabetes.

The Monte Carlo code MCML (Monte Carlo modeling of light transport in multi-layered tissue) has been the gold standard for simulations of light transport in multi-layer tissue, but it is ineffective in the presence of three-dimensional (3D) heterogeneity. New techniques have been attempted to resolve this problem, such as MCLS, which is derived from MCML, and tMCimg, which draws upon image datasets. Nevertheless, these approaches are insufficient because of their low precision or simplistic modeling. We report on the development of a novel model for photon migration in voxelized media (MCVM) with 3D heterogeneity. Voxel crossing detection and refractive-index-unmatched boundaries were considered to improve the precision and eliminate dependence on refractive-index-matched tissue. Using a semi-infinite homogeneous medium, steady-state and time-resolved simulations of MCVM agreed well with MCML, with high precision (～100%) for the total diffuse reflectance and total fractional absorption compared to those of tMCimg (<70%). Based on a refractive-index-matched heterogeneous skin model, the results of MCVM were found to coincide with those of MCLS. Finally, MCVM was applied to a two-layered sphere with multi-inclusions, which is an example of a 3D heterogeneous media with refractive-index-unmatched boundaries. MCVM provided a reliable model for simulation of photon migration in voxelized 3D heterogeneous media, and it was developed to be a flexible and simple software tool that delivers high-precision results.

Cortical spreading depression (CSD) is a wave of neuronal and glial depolarization that propagates across the cortex at a rate of 2–5mm/min accompanied by reversible electroencephalogram (EEG) suppression, a negative shift of direct current (DC) potential, and change of optical intrinsic signals (OIS). Propagation velocity of CSD is an important parameter used to study this phenomenon. It is commonly determined in an electrophysiological way that measures the time required for a CSD wave to pass along two electrodes. Since the electrophysiology technique fails to reveal the spreading pattern of CSD, velocity calculated in this manner might be inaccurate. In this study, we combined the electrophysiological recording and OIS imaging (OISI) for detecting changes in DC potential and OIS during CSD simultaneously. An optical method based on OISI to determine the CSD velocity, which is measured by generating a series of regions of interest (ROI) perpendicular to the advancing wavefront along propagation direction of CSD at different time points and then dividing by the distance between ROIs over time, is presented. Comparison of the accuracy of the two approaches in determining the CSD velocity is made as well. The average rate of 33 CSDs is 3.52 ± 0.87mm/min by use of the optical method and 4.36 ± 1.65mm/min by use of the electrophysiological method. Because of the information about spreading pattern of CSD provided optically, the velocity determined by OISI is of smaller deviation and higher accuracy.

We have recently proposed an optical method for assessing heart structure that uses polarized light measurement of birefringence as an indicator of tissue anisotropy. The highly aligned nature of healthy cardiac muscle tissue has a detectable effect on the polarization of light, resulting in a measurable phase shift (“retardance”). When this organized tissue structure is perturbed, for example after cardiac infarction (heart attack), scar tissue containing disorganized collagen is formed, causing a decrease in the measured retardance values. However, these are dependent not only on tissue anisotropy, but also on the angle between the tissue’s optical anisotropy direction and the beam interrogating the sample. To remove this experimental ambiguity, we present a method that interrogates the sample at two different incident beam angles, thus yielding enough information to uniquely determine the true magnitude and orientation of the tissue optical anisotropy. We use an infarcted porcine heart model to compare these polarimetryderived anisotropy metrics with those obtained with diffusion tensor magnetic resonance imaging (DT-MRI). The latter yields the anisotropy and the direction of tissue water diffusivity, providing an independent measure of tissue anisotropy. The optical and MR results are thus directly compared in a common ex vivo biological model of interest, yielding reasonable agreement but also highlighting some technique-specific differences.

Cortical spreading depression (CSD) is a pathophysiological phenomenon. There are sufficient evidences to prove that CSD plays an important role in some neurological disorders. However, exact mechanisms of its initiation and propagation are still unclear. Previous studies showed that glutamate receptors could be concerned with CSD, but those studies were mostly performed oriented to ionotropic glutamate receptors (iGluRs). There is relatively little report about effects of metabotropic glutamate receptors (mGluRs) on CSD. Here, we applied optical intrinsic signal imaging (OISI) combined with direct current (DC) potential recording to examine influences of some mGluRs antagonist (or agonist) on CSD propagation in rat’s brain, to indirectly validate actions of some mGluRs on CSD. We found that N-acetyl-l-aspartyl-l-glutamate (NAAG, an agonist at mGluR3) inhibited the propagation of CSD, and the inhibition was gradually developed with time. However, 6-methyl-2-phenylethynyl-pyridine (MPEP, an antagonist of mGluR5) did not produce any significant alterations with the CSD propagation. Our findings suggest that mGluR3 could play an important role in the CSD propagation, but the activity of mGluR5 was comparatively weak. These findings can help to understand the propagation mechanism of CSD, and consider the therapy of some neurological diseases involved with CSD.

A new personal recognition system using the palm vein pattern is presented in this article. It is the first time that the palm vein pattern is used for personal recognition. The texture feature of palm vein is extracted by wavelet decomposition. With our palm vein image database, we employed the nearest neighbor (NN) classifier to test the performance of the system. Experimental results show that the algorithm based on wavelet transform can reach a correct recognition rate (CRR) of 98.8%.

The water quality testing principle by surface plasmon resonance (SPR) is introduced. Using the scanning mode angular spectral testing and the CCD angular spectral testing, a kind of highresolution, wide-range, and portable optical waveguide SPR angular spectral testing system is studied, the method of improving the testing accuracy is discussed, and a long-life surface plasmon optical waveguide transducer is also proposed. Utilizing the SPR testing system, we contrastively tack some test for several sorts of solution, the results presented that significant differences of SPR peaks observed in different sorts of liquid, which indicated the effectiveness of SPR technology used in water quality testing and analysis.

The early stage of exercises is crucial in sports training; however, its physiological mechanism is still unclear. The hemodynamic response was reported to be associated with respiratory exchange. Here, we aimed to explore the relationship between oxy-hemoglobin concentration change (HbO2) and respiratory exchange ratio (RER) during the early phase of exercises. Sixteen athletes of middle-distance race were selected from Wuhan Institute of Physical Education to conduct intermittent exercises on MERCURY4.0 at 80% VO2peak intensity. Multiple physiological parameters were acquired by use of a near-infrared spectroscopy muscle oxygen monitor, a Cardiopulmonary Function MAX-II and a P-Lar, including HbO2, RER and others. A significant correlation was found between RER and HbO2 in quadriceps muscle in the thigh during the early phase of exercises. Thus, NIRS is capable of supervising sports training in terms of HbO2, which actually acted as an interpreter of RER change.