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Pelivanov I.M.,Moscow State University | Simonova V.A.,Institute of Laser and Information Technologies | Khokhlova T.D.,University of Washington | Karabutov A.A.,Moscow State University
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2010

In this work the spatial resolution provided by the array transducers in 2D optoacoustic (OA) imaging is considered numerically. The resolution is determined from the point spread function (PSF) of an array, that is a 2D OA image of a point source of the spherical acoustic wave. Numerical simulations consisted of the following steps. First, the OA signals excited by the point source and detected by each element of the array calculated using the Rayleigh integral. Radial backprojection algorithm was then employed to obtain the image of the point source in the imaging plane. The influence of the geometrical parameters of array elements, number of the detectors and a single detector bandwidth on the PSF was studied in detail. It was shown that the spatial resolution provided by the array transducer in the imaging plane can be unambiguously determined from the detector frequency band, array aperture angle and the width of a single array detector, and does not depend on the number of the detectors. © 2010 Copyright SPIE - The International Society for Optical Engineering. Source


Kosarev I.N.,Institute of Laser and Information Technologies
Technical Physics | Year: 2014

Electron dynamics in a thin target irradiated with femtosecond laser pulses at an intensity of 1020 W/cm2 is studied in the framework of the kinetic theory of laser plasma based on the construction of propagators (in classical limit) for electron and ion distribution functions in plasma. The calculations are performed for real densities and charges of plasma ions. Electrons are partly ejected from the target. The laser pulse energy is predominantly absorbed by electrons, and the electrons are accelerated to relatively high energies. © 2014 Pleiades Publishing, Ltd. Source


Kotova S.L.,RAS Semenov Institute of Chemical Physics | Timashev P.S.,Institute of Laser and Information Technologies | Guller A.E.,Macquarie University | Shekhter A.B.,RAS Sechenov Institute of Evolutionary Physiology and Biochemistry | And 3 more authors.
Microscopy and Microanalysis | Year: 2015

We used atomic force microscopy (AFM) to diagnose pathological changes in the extracellular matrix (ECM) of skin connective tissue in patients with pelvic organ prolapse (POP). POP is a common condition affecting women that considerably decreases the patients' quality of life. Deviations from normal morphology of the skin ECM from patients with POP occur including packing and arrangement of individual collagen fibers and arrangement of collagen fibrils. The nanoindentation study revealed significant deterioration of the mechanical properties of collagen fibril bundles in the skin of POP patients as compared with the skin of healthy subjects. Changes in the skin ECM appeared to correlate well with changes in the ECM of the pelvic ligament tissue associated with POP. AFM data on the ECM structure of normal and pathologically altered connective tissue were in agreement with results of the standard histological study on the same clinical specimens. Thus, AFM and related techniques may serve as independent or complementary diagnostic tools for tracking POP-related pathological changes of connective tissue. © Microscopy Society of America 2015. Source


Timashev P.S.,Institute of Laser and Information Technologies | Kotova S.L.,RAS Semenov Institute of Chemical Physics | Belkova G.V.,RAS Semenov Institute of Chemical Physics | Gubar'Kova E.V.,Nizhny Novgorod State Medical Academy | And 3 more authors.
Microscopy and Microanalysis | Year: 2016

Cardiovascular disease remains the leading cause of mortality worldwide. Here we suggest a novel approach for tracking atherosclerosis progression based on the use of atomic force microscopy (AFM). Using AFM, we studied cross-sections of coronary arteries with the following types of lesions: Type II - thickened intima; Type III - thickened intima with a lipid streak; Type IV - fibrotic layer over a lipid core; Type Va - unstable fibrotic layer over a lipid core; Type Vc - very thick fibrotic layer. AFM imaging revealed that the fibrotic layer of an atherosclerotic plaque is represented by a basket-weave network of collagen fibers and a subscale network of fibrils that become looser with atherosclerosis progression. In an unstable plaque (Type Va), packing of the collagen fibers and fibrils becomes even less uniform than that at the previous stages, while a stable fibrotic plaque (Vc) has significantly tighter packing. Such alterations of the collagen network morphology apparently, led to deterioration of the Type Va plaque mechanical properties, that, in turn, resulted in its instability and propensity to rupture. Thus, AFM may serve as a useful tool for tracking atherosclerosis progression in the arterial wall tissue. © Microscopy Society of America 2016. Source


Gonchukov S.,National Research Nuclear University MEPhI | Sukhinina A.,National Research Nuclear University MEPhI | Bakhmutov D.,Moscow State University | Biryukova T.,Moscow State University | And 2 more authors.
Laser Physics Letters | Year: 2013

In view of its wealth of molecular information, Raman spectroscopy has been the subject of active biomedical research. The aim of this work is Raman spectroscopy (RS) application for the determination of molecular biomarkers in saliva with the objective of early periodontitis detection. As was shown in our previous study, carotenoids contained in saliva can be molecular fingerprint information for the periodontitis level. It is shown here that the carotenoid RS lines at wavenumbers of 1156 and 1524 cm-1 can be easily detected and serve as reliable biomarkers of periodontitis using resonance Raman spectroscopy of dry saliva. © 2013 Astro Ltd. Source

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