22 results match your criteria: "A.V. Gaponov-Grekhov Institute of Applied Physics[Affiliation]"

The far-infrared absorption spectrum of monodeuterated water vapor, HDO, is analyzed using three high-sensitivity absorption spectra recorded by high-resolution Fourier transform spectroscopy at the SOLEIL synchrotron facility. The gas sample was obtained using a 1:1 mixture of HO and DO leading to a HDO abundance close to 50%. The room temperature spectra recorded in the 50-720 cm range cover most of the rotational band.

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We report a new application of the recently developed technique, Optical Coherence Elastography (OCE) to quantitatively visualize kinetics of osmotic strains due to diffusive penetration of various osmotically active solutions into biological tissues. The magnitude of osmotic strains may range from fractions of one per cent to tens per cent. The visualized spatio-tempotal dynamics of the strains reflect the rates of osmotic dehydration and diffusional penetration of the active solute, which can be controlled by concentration of the solution components.

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We propose a nonlinear stress-strain law to describe nonlinear elastic properties of biological tissues using an analogy with the derivation of nonlinear constitutive laws for cracked rocks. The derivation of such a constitutive equation has been stimulated by the recently developed experimental technique-quasistatic Compression Optical Coherence Elastography (C-OCE). C-OCE enables obtaining nonlinear stress-strain dependences relating the applied uniaxial compressive stress and the axial component of the resultant strain in the tissue.

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: The most important phase in the endometrial pathologies diagnostics is the histological examination of tissue biopsies obtained under visual hysteroscopic control. However, the unclear visual diagnostics characteristics of subtle focal endometrial pathologies often lead to selection errors regarding suspicious endometrial lesions and to a subsequent false pathological diagnosis/underestimation of precancer or early-stage cancer. : In this study, we investigate the potential of Multimodal Optical Coherence Tomography (MM OCT) to verify suspicious endometrial lesion regions before biopsy collection.

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Article Synopsis
  • Hidden data recovery is important in fields like neurophysiology due to issues with incomplete or corrupted experimental data.
  • This study examines the use of reservoir computing (RC) for recovering hidden data from both model systems and real EEG signals, finding that RC is more effective than linear regression (LR) in these cases.
  • The research suggests that RC can enhance data recovery processes, leading to improved accuracy and reliability in neurophysiological studies, which is critical for scientific analysis.
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While cryotherapy is one of the traditional ways to reduce postoperative complications in maxillofacial surgery, the cooling degree is not regulated in most cases and the achieved effect is not properly controlled. Therefore, to develop optimal cooling modes, we propose to study the buccal vascular response to cooling, which has not been previously shown. To evaluate the effect of cooling, we analyzed vessel networks using optical coherence tomography angiography (OCT-A).

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Powerful wildfires occurring in Siberia each summer emit large amounts of smoke aerosol that, according to studies of the environmental impacts of biomass burning (BB) aerosol in different regions of the world, can affect precipitation and other weather parameters and induce feedback on fires. However, the knowledge of smoke-weather interactions and fire-weather feedback in Siberia is presently limited. To advance this knowledge, we performed coupled-meteorology-chemistry simulations of aerosols and weather in a Siberian region covering taiga and tundra using the CHIMERE chemistry-transport model and the WRF meteorological model.

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Article Synopsis
  • - The study introduces a new use of compression optical coherence elastography (C-OCE) to track damage in small intestine layers of minipigs (n = 36) as they are stretched.
  • - C-OCE measured the stiffness of different intestine wall layers and identified a significant drop in stiffness in the longitudinal muscular layer at 25% elongation, indicating potential tears.
  • - The results suggest that C-OCE could effectively predict safe stretching limits of intestinal tissues, which could be crucial for preventing ruptures during medical procedures.
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Localized wave structures: Solitons and beyond.

Chaos

June 2024

School of Mathematics, Physics and Computing, University of Southern Queensland, Toowoomba, Australia.

The review is concerned with solitary waves and other localized structures in the systems described by a variety of generalizations of the Korteweg-de Vries (KdV) equation. Among the topics we focus upon are "radiating solitons," the generic structures made of soliton-like pulses, and oscillating tails. We also review the properties of solitary waves in the generalized KdV equations with the modular and "sublinear" nonlinearities.

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This study highlights the potential of scanning optoacoustic angiography (OA) in identifying alterations of superficial vasculature in patients with post-thrombotic syndrome (PTS) of the foot, a venous stress disorder associated with significant morbidity developing from long-term effects of deep venous thrombosis. The traditional angiography methods available in the clinics are not capable of reliably assessing the state of peripheral veins that provide blood outflow from the skin, a key hallmark of personalized risks of PTS formation after venous thrombosis. Our findings indicate that OA can detect an increase in blood volume, diameter, and tortuosity of superficial blood vessels.

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Detailed analysis of the unique broadband millimeter-wave (70-360 GHz) collision-induced absorption spectra in pure CO and in its mixture with Ar is presented. The nature of the observed continuum absorption is examined using classical trajectory simulation along with statistical physics consideration. Bimolecular continuum is decomposed in the phase space into separate contributions from the so-called free, quasibound, and true bound molecular pairs, the proportions of which greatly vary with temperature.

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For the most popular method of scan formation in Optical Coherence Tomography (OCT) based on plane-parallel scanning of the illuminating beam, we present a compact but rigorous K-space description in which the spectral representation is used to describe both the axial and lateral structure of the illuminating/received OCT signals. Along with the majority of descriptions of OCT-image formation, the discussed approach relies on the basic principle of OCT operation, in which ballistic backscattering of the illuminating light is assumed. This single-scattering assumption is the main limitation, whereas in other aspects, the presented approach is rather general.

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Article Synopsis
  • * Current methods have limitations in accuracy, prompting research into better techniques, particularly by analyzing speckle patterns in OCT images.
  • * The study found that local brightness fluctuations from wavelet analysis of OCT data improve the differentiation of glioma from healthy brain tissue, suggesting this approach could enhance neurosurgical diagnostics.
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Optical coherence elastography (OCE) demonstrated impressive abilities for diagnosing tissue types/states using differences in their biomechanics. Usually, OCE visualizes tissue deformation induced by some additional stimulus (e.g.

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In this study, we focus on training recurrent spiking neural networks to generate spatiotemporal patterns in the form of closed two-dimensional trajectories. Spike trains in the trained networks are examined in terms of their dissimilarity using the Victor-Purpura distance. We apply algebraic topology methods to the matrices obtained by rank-ordering the entries of the distance matrices, specifically calculating the persistence barcodes and Betti curves.

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In this paper, we report on a study regarding the efficiency of the post-operational phototherapy of the tumor bed after resection with both a cold knife and a laser scalpel in laboratory mice with CT-26 tumors. Post-operational processing included photodynamic therapy (PDT) with a topically applied chlorin-based photosensitizer (PS), performed at wavelengths of 405 or 660 nm, with a total dose of 150 J/cm. The selected design of the tumor model yielded zero recurrence in the laser scalpel group and 92% recurrence in the cold knife group without post-processing, confirming the efficiency of the laser scalpel in oncology against the cold knife.

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A class of adaptation functions is found for which a synchronous mode with different number of phase clusters exists in a network of phase oscillators with triadic couplings. This mode is implemented in a fairly wide range of initial conditions and the maximum number of phase clusters is four. The joint influence of coupling strength and adaptation parameters on synchronization in the network has been studied.

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This article presents the results of evaluating the possibility of conducting radio astronomy studies in the windows of atmospheric transparency ~100, ~230, and ~350 GHz using the optical Big Telescope Alt-Azimuthal (BTA) of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). A list of some promising astronomical tasks is proposed. The astroclimat conditions at the BTA site and possible optical, cryogenic, and mechanical interfaces for mounting a superconducting radio receiver at the focus of the optical telescope are considered.

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The collective Thomson scattering of high-power millimeter-wave radiation on plasma density fluctuations (CTS) is widely used for diagnosing the velocity distribution function of energetic ions in fusion plasma. In this paper, we discuss a non-standard scheme of CTS measurements, which exploits strong refraction of probing and scattered microwave beams when reflecting from the cut-off layer in dense plasma. The scheme may be realized with the existing CTS diagnostic system at the Gas-Dynamic Trap (GDT) facility, a large open magnetic trap operating at Budker Institute (Novosibirsk, Russia).

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The generation of coherent light based on inelastic stimulated Raman scattering in photonic microresonators has been attracting great interest in recent years. Tellurite glasses are promising materials for such microdevices since they have large Raman gain and large Raman frequency shift. We experimentally obtained Raman lasing at a wavelength of 1.

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How complex patterns generated by neural systems are represented in individual neuronal activity is an essential problem in computational neuroscience as well as machine learning communities. Here, based on recurrent neural networks in the form of feedback reservoir computers, we show microscopic features resulting in generating spatiotemporal patterns including multicluster and chimera states. We show the effect of individual neural trajectories as well as whole-network activity distributions on exhibiting particular regimes.

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Adaptive interactions are an important property of many real-word network systems. A feature of such networks is the change in their connectivity depending on the current states of the interacting elements. In this work, we study the question of how the heterogeneous character of adaptive couplings influences the emergence of new scenarios in the collective behavior of networks.

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