666 research outputs found

    Accuracy and efficiency of electronic energies from systematic molecular fragmentation

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    A systematic method for approximating the ab initio electronic energy of molecules from the energies of molecular fragments is tested on a large sample of typical organic molecular structures. The detailed methods, including some additional refinements for molecular rings and long range interactions, are described. The accuracy and computational efficiency of the systematic hierarchy of methods are reported

    Role of macrophages in pathomorphogenesis of alcoholic liver disease

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    Alcoholic liver disease combines various structural and functional impairments of liver caused by excessive alcohol consumption. Alcohol, as a direct hepatotoxic agent, is metabolized in the liver and affects both resident cells and their microenvironment. These changes are reflected in the resulting imbalance of pro- and anti-inflammatory mediators synthesized by the liver macrophages. To date, it is known about the polarization and phenotypic diversity of this cell population, and about macrophages and monocytes involvement in the development of alcoholic hepatitis. These facts allow us to consider macrophages as potential therapeutic targets. However, the available data do not fully disclose the mechanisms of inter- and intradifferon interactions in the human body. The review discusses the results of current studies on the involvement of liver macrophages in the pathomorphogenesis of alcoholic liver disease and the potential for their use in the treatment of this disease

    Caroli syndrome: a clinical case with detailed histopathological analysis

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    © 2018, Japanese Society of Gastroenterology. Herein we present a clinical case of the Caroli syndrome caused by the compound heterozygous mutation in the PKHD1 gene. Histopathological assessment of liver detected biliary cirrhosis, numerous dilated bile ducts of various sizes, hyperplastic cholangiocytes containing a large amount of acid mucopolysaccharides, decreased ß-tubulin expression and increased proliferation of cholangiocytes. A significant proportion of hepatic tissue was composed of giant cysts lined with a single layer of cholangiocytes, containing pus and bile in its lumen and surrounded by granulation tissue. An accumulation of neutrophils in the lumen of the bile ducts was observed, as well as an infiltration of the ducts and cysts surrounding connective tissue by CD4+ and to a lesser extent CD8+ lymphocytes. This may be caused by the expression of HLA-DR by cholangiocytes. Atrophy and desquamation of the epithelium of collecting tubules with the formation of microcysts were detected in the kidneys without a clinically significant loss of renal function. Morphopathogenetic mechanisms of the Caroli syndrome can be targets for a potential pathogenetic therapy and prevention of its manifestations and complications

    Ordinary and Activated Bone Grafts: Applied Classification and the Main Features

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    © 2015 R. V. Deev et al. Bone grafts are medical devices that are in high demand in clinical practice for substitution of bone defects and recovery of atrophic bone regions. Based on the analysis of the modern groups of bone grafts, the particularities of their composition, the mechanisms of their biological effects, and their therapeutic indications, applicable classification was proposed that separates the bone substitutes into "ordinary" and "activated." The main differential criterion is the presence of biologically active components in the material that are standardized by qualitative and quantitative parameters: growth factors, cells, or gene constructions encoding growth factors. The pronounced osteoinductive and (or) osteogenic properties of activated osteoplastic materials allow drawing upon their efficacy in the substitution of large bone defects

    Non-natural nucleosides based on 1,2,4-triazolo[5,1-c][1,2,4]triazin-4(6H)- ones

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    Two regioselective methods for the synthesis of nucleosides in the series of 3-phenyl- and 3- ethoxycarbonyl-1,2,4-triazolo[5,1-c][1,2,4]triazin-4-ones were developed. The first route involves a Vorbrüggen glycosylation reaction. The second one is based on condensation of 1,2,4- triazolo[5,1-c][1,2, 4]triazin-4-one sodium salts with protected 1-bromo-sugar derivatives

    A Numerical Model of an Electrostatic Precipitator

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    This paper presents a Computational Fluid Dynamics (CFD) model for a wire-plate electrostatic precipitator (ESP). The turbulent gas flow and the particle motion under electrostatic forces are modelled using the CFD code FLUENT. Numerical calculations for the gas flow are carried out by solving the Reynolds-averaged Navier-Stokes equations and turbulence is modelled using the k-ε turbulence model. An additional source term is added to the gas flow equation to capture the effect of electric field. This additional source term is obtained by solving a coupled system of the electric field and charge transport equations. The particle phase is simulated by using Discrete Phase Model (DPM). The results of the simulation are presented showing the particle trajectory inside the ESP under the influence of both aerodynamic and electrostatic forces. The simulated results have been validated by the established data. The model developed is useful to gain insight into the particle collection phenomena that takes place inside an industrial ESP

    Synthesis of acyclic nucleoside analogues by one-step Vorbrüggen glyco-sylation of 1,2,4-triazolo[1,5-a]pyrimidine-7-ones

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    New analogues of acyclovir have been prepared by reacting 1,2,4 -triazolo[1,5-a]pyrimidin-7-ones 1а-i and (2-acetoxyethoxy)methyl acetate 2 in the presence of trimethylsilyl trifluoromethanesulfonate as a catalyst. The interaction between the compounds 1а-е and 2 has led to a mixture of N3 and N4 isomers. In contrast, the reaction of compounds 1g-i and 2 proceeded selectively to form N3 isomers. In the case of compounds 1a-c the predominant product is the one with the acyclic moiety in azine ring (N4 isomer). Interaction between 1d-f and 2 has led to mixtures comprising mainly N3 isomer. It has been found that the ratio of glycosylation products 1 and 2 are thermodynamically controlled. The structure of the obtained compounds has been proved by 1Н, 13С, two-dimensional 1Н-13С NMR spectroscopy and X-ray analysis

    Can co-management improve governance of a common-pool resource? : lessons from a framed field experiment in a marine protected area in the Colombian Caribbean

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    Complexities associated with the management of common pool resources (CPR) threaten governance at some marine protected areas (MPA). In this paper, using economic experimental games (EEG), we investigate the effects of both external regulation and the complementarities between internal regulation and non-coercive authority intervention—what we call comanagement— on fishermen’s extraction decisions. We perform EEG with fishermen inhabiting the influence zone of an MPA in the Colombian Caribbean. The results show that comanagement exhibits the best results, both in terms of resource sustainability and reduction in extraction, highlighting the importance of strategies that recognize communities as key actors in the decision-making process for the sustainable use and conservation of CPR in protected areas

    The rationality of using DNA diagnostics in sports cardiology

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    NGS is becoming an integral part of medical practice, including in cardiology. The role of genes in the formation of diseases of the cardiovascular system has been actively studied for the last 20 years. Currently, heart diseases with a hereditary component are usually divided into two large groups: monogenic syndromes that lead to an unfavorable outcome, including sudden cardiac death at a young age, and polygenic conditions that manifest after 35 years and are accompanied by deterioration in the quality of life. In professional sports, changes in the myocardium are almost inevitable, however, the first phenotypic signs of hereditary myocardial disease may be hidden behind adaptive changes, which are commonly called “athlete’s heart”. The carriage of causative genes radically changes the approach to the management of an athlete: his admission to training and competitive activities is reviewed, the volume of permissible load and the frequency of visits to a cardiologist are discussed. In this paper, we tried to identify clinical markers — «red flags» that would indicate the need for genetic testing on the example of athletes who underwent an in-depth medical examination in 2021–2022

    Long-range 1H-15N J couplings providing a method for direct studies of the structure and azide-tetrazole equilibrium in a series of azido-1,2,4-triazines and azidopyrimidines

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    The selectively 15N labeled azido-1,2,4-triazine 2*A and azidopyrimidine 4*A were synthesized by treating hydrazinoazines with 15N-labeled nitrous acid. The synthesized compounds were studied by 1H, 13C, and 15N NMR spectroscopy in DMSO, TFA, and DMSO/TFA solutions, where the azide-tetrazole equilibrium could lead to the formation of two tetrazoles (T, T′) and one azide (A) isomer for each compound. The incorporation of the 15N label led to the appearance of long-range 1H-15N coupling constants (JHN), which can be measured easily by using amplitude-modulated 1D 1H spin-echo experiments with selective inversion of the 15N nuclei. The observed JHN patterns enable the unambiguous determination of the mode of fusion between the azole and azine rings in the two groups of tetrazole isomers (2*T′, 4*T′ and 2*T, 4*T), even for minor isoforms with a low concentration in solution. However, the azide isomers (2*A and 4*A) are characterized by the absence of detectable J HN coupling. The analysis of the JHN couplings in 15N-labeled compounds provides a simple and efficient method for direct NMR studies of the azide-tetrazole equilibrium in solution. © 2013 American Chemical Society
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