Application of Optical Methods in Blood Studies upon Evaluation of Severity Rate of Diffuse Liver Pathology

Possible early diagnostic application of optical methods (dielectrophoresis, spectral and imaging ellipsometry, Fourier-transform infrared spectroscopy, Raman spectroscopy) in studies of red blood cells and serum of patients with diffuse liver disease with varying degrees of fibrosis has been evaluated. Application of combined optical methods was confirmed to significantly improve the performance of sensitivity, specificity, and accuracy index as well as to achieve the reliable results in diagnosis of both severe fibrosis and slight ulterior liver fibrosis. Identified diagnostic potential of optical methods can be effectively utilized in noninvasive screening evaluation of stages of diffuse liver disease of various geneses.

Peculiarities of Erythrocytic Parameters in Patients with Nonalcoholic Steatohepatitis

Thirty-seven males with non-alcoholic staatohepatitis (NASH) (aged 39 - 62) were included in the study. Clinical, biochemical and instrumental studies were used to verify the diagnosis. The control group was comprised of thirty-three males of comparable age and without confirmed signs of liver diseases and other pathology of inner organs. Dielectrophoresis was applied to evaluate the structural-and-functional erythrocytic parameters. The patients with NASH erythrocytes tended to differ in their much lower amplitude deformation, polarizability, capacity of erythrocytic membranes, pace of translational motion of cells towards electrodes and much higher levels of overall indices of rigidity, viscosity, electroconductivity, destruction and aggregation as compared to the control group (p < 0.001 - 0.05). We discovered cases of correlation of erythrocytic parameters with biochemical findings reflecting inflammatory and cytolytic syndrome, cholestasis, protein-synthesizing liver function as well as markers of metabolic syndrome (BMI, changes in arterial blood pressure, the degree of disturbances in carbohydrate metabolism, atherogenic dyslipidemia) and microalbuminuria. Aggravation of microcirculatory disturbances leading to an increase of fibrogenes is induced by changes in the properties of erythrocytes under NASH suggests the administration of a number of therapeutic techniques which could improve the status of the parameters of red blood cells. This study aims to evaluate the peculiarities of electric and viscoelastic behavior of erythrocytes in patients with primary NASH in order to determine additional methods of treatment for this disease.

Epitaxial Ge Growth on Si(111) Covered with Ultrathin SiO₂Films

The epitaxial growth of Ge on Si(111) covered with the 0.3 nm thick SiO2 film is studied by scanning tunneling microscopy. Nanoareas of bare Si in the SiO2 film are prepared by Ge deposition at a temperature in the range of 570℃-650℃ due to the formation of volatile SiO and GeO molecules. The surface morphology of Ge layers grown further at 360℃-500℃ is composed of facets and large flat areas with the Ge(111)-c(2 × 8) reconstruction which is typical of unstrained Ge. Orientations of the facets, which depend on the growth temperature, are identified. The growth at 250℃-300℃ produces continuous epitaxial Ge layers on Si(111). A comparison of the surface morphology of Ge layers grown on bare and SiO2-film covered Si(111) surfaces shows a significantly lower Ge-Si intermixing in the latter case due to a reduction in the lattice strain. The found approach to reduce the strain suggests the opportunity of the thin continuous epitaxial Ge layer formation on Si(111).

Light emission of heavily doped AlGaN structures under optical pumping

Spectral, temporal and polarization characteristics of spontaneous and stimulated luminescence of Al0.5Ga0.5N/A1N structures grown by molecular beam epitaxy were studied at the optical pulsed pumping with 2 = 266 nm. Samples with a high degree of silicon doping were investigated. The vast majority of radiation falls on transitions within the band gap between the levels of defects. As a result, the radiation band embracing the whole visible range of more than 300 THz is observed in both spontaneous radiation and induced luminescence. In spon- taneous radiation the band has a smooth spectral intensity distribution over the wavelengths, whereas induced radi- ation has its sharp peaks corresponding to the mode structure of the planar waveguide. The measured gain of the active medium is g ≈ 70 cm 1 for a weak signal.

Revealing the underlying mechanisms behind TE extraordinary THz transmission

Transmission through seemingly opaque surfaces,so-called extraordinary transmission,provides an exciting platform for strong light–matter interaction,spectroscopy,optical trapping,and color filtering.Much of the effort has been devoted to understanding and exploiting TM extraordinary transmission,while TE anomalous extraordinary transmission has been largely omitted in the literature.This is regrettable from a practical point of view since the stronger dependence of the TE anomalous extraordinary transmission on the array’s substrate provides additional design parameters for exploitation.To provide high-performance and cost-effective applications based on TE anomalous extraordinary transmission,a complete physical insight about the underlying mechanisms of the phenomenon must be first laid down.To this end,resorting to a combined methodology including quasi-optical terahertz(THz)time-domain measurements,full-wave simulations,and method of moments analysis,subwavelength slit arrays under s-polarized illumination are studied here,filling the void in the current literature.We believe this work unequivocally reveals the leaky-wave role of the grounded-dielectric slab mode mediating in TE anomalous extraordinary transmission and provides the necessary framework to design practical high-performance THz components and systems.