The characteristic operational features of different flowmeters and devices for measuring the coolant and feedwater flows in the loops of nuclear steam generating facilities (NSGF) currently ...operating in NPP are analyzed. A new design has been developed for labeled nuclear-magnetic flowmeter-relaxometers with a new flow measuring regime. This regime and other new structural solutions in the new devices have made it possible to perform measurements with accuracy to within <1%. The results of measurements of the flow and the longitudinal and transverse relaxation times for different fl owing media at different temperatures are presented. It is shown that the developed labeled nuclear-magnetic flowmeter-relaxometer is an expedient tool for monitoring the parameters of the coolant and feedwater in the NSGF loops.
In this study, wide-angle X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy were employed to address the crystalline structure and morphology of ...poly(p-xylylene)–PbS nanocomposite thin films prepared by vapor deposition polymerization as well as their evolution upon thermal annealing. It was found that as-synthesized samples with different PbS contents demonstrate similar diffraction patterns that cannot be fully ascribed to a decrease in crystallite size, indicating distorted crystal structure of PbS nanoparticles compared to the bulk PbS. X-ray absorption spectroscopy reveals wide distribution of Pb–S bond lengths with a minimum value of 2.67 Å, which can be attributed to the presence of molecular (PbS) n clusters in the studied films. It was shown that thermal annealing can be used to control the size of PbS nanoparticles and, as a consequence, optical properties of the composite films. The UV–vis absorption spectra demonstrate pronounced red shift of the absorption edge correlated with the growth of PbS nanoparticles upon annealing. Comprehensive analysis of several theoretical models describing the effect of nanoparticles size on optical band gap of the composite material has been performed and compared with the experimental data.
Aim: tosystematize the literature data on endoscopic semiotics and morphological changes in the gastric mucosa in autoimmune gastritis. Key points. Autoimmune gastritis is associated with an ...increased risk of developing adenocarcinoma and neuroendocrine tumours of the stomach. Clarification of diagnostic criteria for autoimmune gastritis is essential for gastroenterological practice. The diagnosis is based on the results of endoscopic and histological examination, and on data from laboratory tests. Isolated atrophy of the mucous membrane of the body of the stomach, the presence of difficult-to-wash creamy mucus, changes in the mucous membrane like “shed skin”, and the presence of whitish globule-like foci are typical endoscopic signs of autoimmune gastritis. Widespread pseudopyloric metaplasia, focal intestinal and pseudopancreatic metaplasia, hyperplasia of the ridges of the mucous membrane of the body of the stomach and their relationship to the glandular layer as in the antrum allow during a morphological study considering clinical data to suspect and verify autoimmune gastritis. Conclusion. During instrumental examination, knowledge of endoscopic symptoms and pathognomonic morphological changes is important for the timely diagnosis of autoimmune gastritis.
The kinetics and mechanism of benzoyl peroxide- and azobisisobutyronitrile-initiated polymerization of acrylic acid and methyl acrylate in the temperature range of 20–40°C have been investigated. In ...the case of evacuation of the monomer + initiator system, the polymerization proceeds without heating or other energetic impacts on the system. The polymer yield depends on the initiator concentration and the temperature and time of sample thermostating. It has been shown by EPR that the monomers affect the rate of initiator decomposition into radicals. The structures of intermediate complexes formed in the acrylic acid + azobisisobutyronitrile system have been determined by quantum-chemical calculations, and the activation energies of the relevant processes have been calculated.
Using EPR spectroscopy, it has been established that monomers affect the decomposition rate of their polymerization initiators by forming complexes with them. Several structures of the complexes have ...been optimized, and their decomposition mechanisms, the activation energies of the chain initiation and propagation reactions, and the heat of polymerization have been determined by means of quantum chemistry methods. In the absence of radical inhibitors (evacuation), the polymerization proceeds with high efficiency (98%) at room temperature without stimulation of the system with external energy.
Traditional serrated adenomas (TSAs) are extremely rare polyps from the group of serrated polyps of the colon. TSAs is no more than 5 % of all colon polyps. A relatively small number of studies have ...been devoted to this histological variant, at the same time, some aspects of the morphological diagnosis of TSA still remain undisclosed. Purpose: to conduct a clinical and morphological analysis of cases of TSAs.
Materials and methods
. The study included 57 cases of TSAs diagnosed in the period from 2021 to 2023. In the cases detected during this period, the results of histological and endoscopic studies were analyzed.
Results
. The age of patients ranged from 44 to 78 years and averaged 61.7 years. The ratio of men and women is 1:1.8. Most TSAs were found in the rectum (n = 28) and sigmoid colon (n = 20). In 8 cases, the tumor was localized in the descending part and the splenic flexure of the colon. In 1 observation, a tumor was found in the cecum. The sizes of the polyps ranged from 0.5 cm to 3.5 cm. In 22 cases, the composition of the polyp included tubulovillous adenomas (16 cases) and hyperplastic polyps (6 cases) in addition to TSAs. In 5 cases, foci of highly differentiated adenocarcinoma were detected in the TSAs material.
Conclusion
. TSAs has characteristic morphological features with a serrated exophytic growth pattern, cytoplasmic eosinophilia and the presence of ectopic crypts. Due to the difficulties of morphological diagnosis, TSAs in some cases remains undiagnosed. At the same time, due to the increased malignant potential, TSAs requires special vigilance on the part of pathologists and clinicians.
Circularly polarized light with spin angular momentum is one of the most valuable probes of magnetism. We demonstrate that light beams with orbital angular momentum (OAM), or vortex beams, can also ...couple to magnetism exhibiting dichroisms in a magnetized medium. Resonant optical absorption in a ferrimagnetic crystal depends strongly on both the handedness of the vortex and the direction of the beam propagation with respect to the sample magnetization. This effect exceeds the conventional dichroism for circularly polarized light. Our results demonstrate the high potential of the vortex beams with OAM as a new spectroscopic probe of magnetism in matter.
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The paper is devoted to the modeling and analysis of data detected by the TAIGA-IACT installation in the stereo mode. Five Imaging Atmospheric Cherenkov Telescopes (IACT) with a viewing angle of ...9.6° are expected to be included in the installation. Today there are three telescopes spaced far apart (from 320 to 500 m) in the installation. The effective area of the installation is as large as 0.6 km
2
; therefore, it is possible to conduct statistically significant measurements of weak γ-ray sources in the energy range above 10 TeV over a reasonable observation time (300–400 h). The Monte Carlo procedure for simulating the hadrons and γ-rays detected by the telescopes is described as is the procedure for reconstructing the parameters of extensive air showers, such as the arrival direction of an event, the axis position, the depth of the maximum of shower development (
X
max
), and the primary-particle energy. In order to solve the problem of γ-hadron separation, the criteria for selecting γ-rays detected in the stereo mode have been optimized and the effective area of the installation has been calculated.
Chemical reactions stimulated by γ-radiation in liquid hydrocyanic acid (HCN) in the presence of single-walled edcarbon nanotubes (SWCNTs) have been studied. The polymerization of HCN on the surface ...of nanotubes occurs several times more rapidly than in pure HCN, and the set of radiolysis products becomes poorer. It is likely that the approach of polymerizing reagents on the nanosized surface is limited by specific mutual orientations. Furthermore, the CN and H radicals add to the walls of the nanotubes and the nanotubes become soluble in water, ethanol, and acids.
With the purpose to replace expensive and significantly cytotoxic positively charged polypeptides in biodegradable capsules formed via Layer-by-Layer (LbL) assembly, multilayers of bovine serum ...albumin (BSA) and tannic acid (TA) are obtained and employed for encapsulation and release of model drugs with different solubility in water: hydrophilic-tetramethylrhodamine-isothiocyanate-labeled BSA (TRITC-BSA) and hydrophobic 3,4,9,10-tetra-(hectoxy-carbonyl)-perylene (THCP). Hydrogen bonding is proposed to be predominant within thus formed BSA/TA films. The TRITC-BSA-loaded capsules comprising 6 bilayers of the protein and polyphenol are benchmarked against the shells composed of dextran sulfate (DS) and poly-l-arginine (PARG) on degradability by two proteolytic enzymes with different cleavage site specificity (i.e., α-chymotrypsin and trypsin) and toxicity for murine RAW264.7 macrophage cells. Capsules of both types possess low cytotoxicity taken at concentrations equal or below 50 capsules per cell, and evident susceptibility to α-chymotrypsin resulted in release of TRITC-BSA. While the BSA/TA-based capsules clearly display resistance to treatment with trypsin, the assemblies of DS/PARG extensively degrade. Successful encapsulation of THCP in the TRITC-BSA/TA/BSA multilayer is confirmed, and the release of the model drug is observed in response to treatment with α-chymotrypsin. The thickness, surface morphology, and enzyme-catalyzed degradation process of the BSA/TA-based films are investigated on a planar multilayer comprising 40 bilayers of the protein and polyphenol deposited on a silicon wafer. The developed BSA/TA-based capsules with a protease-specific degradation mechanism are proposed to find applications in personal care, pharmacology, and the development of drug delivery systems including those intravenous injectable and having site-specific release capability.
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