Calculation of neutron radiation attenuation factor with Monte Carlo method

В докладе рассматривается моделирование возможных траекторий движения нейтронов с использованием метода Монте-Карло при прохождении сквозь однородную пластину. Представлен разработанный расчетный код на языке программирования С++, с помощью которого можно определить количество поглощенных, отраженных и прошедших через пластину нейтронов. Исходные данные включают характеристики материала, толщину пластины и количество рассчитываемых траекторий. Результаты работы будут использованы для верификации данных, получаемых с помощью высокопрецизионных расчетных кодов.In the report it is considered the simulation of possible neutron trajectories while passing through a homogenous plate with the help of Monte Carlo method. A developed calculated code using C++ programming language is presented. The code can be used to determine the amount of absorbed, reflected and passed through the plate neutrons. The initial data include the material characteristics, plate thickness and amount of calculated trajectories. The results of this work will be used for the verification of data received with calculation codes of high precision

Energetics of metal slabs and clusters: the rectangle-box model

An expansion of energy characteristics of wide thin slab of thickness L in power of 1/L is constructed using the free-electron approximation and the model of a potential well of finite depth. Accuracy of results in each order of the expansion is analyzed. Size dependences of the work function and electronic elastic force for Au and Na slabs are calculated. It is concluded that the work function of low-dimensional metal structure is always smaller that of semi-infinite metal sample. A mechanism for the Coulomb instability of charged metal clusters, different from Rayleigh's one, is discussed. The two-component model of a metallic cluster yields the different critical sizes depending on a kind of charging particles (electrons or ions). For the cuboid clusters, the electronic spectrum quantization is taken into account. The calculated critical sizes of Ag_{N}^{2-} and Au_{N}^{3-} clusters are in a good agreement with experimental data. A qualitative explanation is suggested for the Coulomb explosion of positively charged Na_{\N}^{n+} clusters at 3<n<5.Comment: 11 pages, 6 figures, 1 tabl

Changes in the indices of prooxidant and antioxidant systems in blood plasma in men with atrophic gastritis and gastric cancer

Aim. To study changes in the indices of prooxidant and antioxidant systems in plasma in men with atrophic gastritis and gastric cancer. Materials and methods. The study included 60 healthy men, 42 patients with atrophic gastritis and 50 men, nicardipine patients with gastric cancer stage II according to TNM. All patients underwent serological diagnosis of diffuse atrophic gastritis (definition of pepsinogens and gastrin-17) and Helicobacter pylori infection. The diagnosis of "atrophic gastritis" was verified by morphological examination of biopsy specimens obtained during fibroesophagogastroduodenoscopy. Diagnosis of gastric cancer was carried out in the Krasnoyarsk regional oncologic dispensary on the basis of a comprehensive instrumental and morphological examination. All patients spectrophotometric methods in plasma was determined the content of diene conjugates (DC), malonic dialdehyde (MDA), glutathione-S-transferase (GST), glutathione peroxidase (GPO), superoxide dismutase (SOD) and catalase. Results. The concentration of SOD, GST, GPO and catalase had no significant differences in patients with atrophic gastritis and gastric cancer and prevailed in comparison with healthy persons. Patients with cancer of the stomach content in the blood plasma DK 2.7 times and MDA at 35.2 times higher than healthy individuals, indicating severe oxidative stress in patients with cancer. In patients with atrophic gastritis was observed similar but less pronounced pattern. Conclusion. The results indicate the presence of oxidative stress in men with atrophic gastritis and gastric cancer

Prevalence and risk factors of irritable bowel syndrome in Irkutsk

Introduction. The study of the problem of irritable bowel syndrome (IBS) in recent years has been very dynamic. In the Rome IV criteria, new criteria for the diagnosis of this pathology were proposed. Along with the existence of ethnic and geographic differ­ences, this has led to an increase in the activity of studies on the prevalence of IBS.Aim. To study the prevalence and risk factors of irritable bowel syndrome in Irkutsk.Materials and methods. A single-stage observational non-randomized study was performed on the basis of three medical institu­tions in Irkutsk. Interviewing and clinical examination were performed in 1 529 people: 724 men and 805 women, average age 51.0 years. The questionnaire contained questions to determine the presence of alarm symptoms. The diagnosis of IBS was based on the Rome IV criteria. IBS with a predominance of diarrhea, IBS with a predominance of constipation and mixed and undiffer­entiated IBS were distinguished. Taking into account the position of the Rome IV criteria and the recommendations of the American College of Gastroenterology (2021), we used a positive diagnosis of IBS in our study and did not perform an instrumental examination of patients.Results. The prevalence of IBS was 12.3%. Among the subtypes of IBS, IBS prevailed with a predominance of constipation (preva­lence 5.7%) and IBS of mixed and undifferentiated type (prevalence 4.6%). Risk factors for IBS were female sex (OR = 0.73; CI 0.53-0.99; p = 0.05), age over 50 years (OR = 0.66; CI 0.48-0.90; p = 0.01) and obesity (OR = 0.46; CI 0.31-0.69; p &lt; 0.001). Risk factors for IBS with a predominance of constipation were female sex (OR = 0.46; CI 0.29-0.73; p = 0.001), age over 50 years (OR = 0.46; CI 0.29-0.73; p = 0.001) and obesity (OR = 0.41; CI 0.23-0.72; p = 0.002).Conclusions. In general, our results are consistent with data from other regions of the world. It should be emphasized that the prevalence of IBS in Irkutsk is quite high, which requires careful attention to this problem

Practical Aspects of Clinical Manifestations, Pathogenesis and Therapy of Alcoholic Liver Disease and Non-alcoholic Fatty Liver Disease: Expert Opinion

Aim: to present the results of an expert discussion of modern aspects of the clinical manifestations, pathogenesis and treatment of alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD).Key points. ALD and NAFLD are characterized by high prevalence and have a significant impact on public health. For the diagnosis of liver pathology, it is important to determine the stage of fibrosis and the severity of the exacerbation of the disease. In the treatment of ALD, it is recommended to achieve abstinence, proper nutrition, the appointment of B vitamins, drugs with cytoprotective activity. In severe hepatitis, corticosteroids may be prescribed. In the treatment of NAFLD, diet and lifestyle modification, weight loss, the use of insulin sensitizers, vitamin E, statins (in the presence of hyperlipidemia) and drugs with metabolic activity are effective.Currently, a point of view is being actively expressed about the synergism of the action of alcohol and the metabolic syndrome on the development of fibrosis, cirrhosis, and hepatocellular carcinoma. The current international consensus recommends a change in the nomenclature of NAFLD and ALD and proposes the terms “metabolically associated steatotic liver disease” and “metabolically associated alcoholic liver disease”.Conclusion. The closeness of the clinical manifestations and pathogenesis of NAFLD and ALD justifies attention to drugs with metabolic activity, which are recommended by the Russian Gastroenterological Association and Russian Scientific Liver Society for the treatment of these diseases. The experts support the suggestion to quantify alcohol consumption in patients with NAFLD in order to change the management of patients, if necessary

Functional activity of peripheral blood monocytes in patients with opisthorchiasis coupled to liver fibrosis intensity

The aim is to examine activity of peripheral blood monocytes from patients with opisthorchiasis coupled to intensity of liver fibrosis. Materials and Methods. A total of 74 patients with chronic opisthorchiasis (39 males and 35 females, average age 42.3 years) and 32 apparently healthy subjects (17 males and 15 females, average age 41.5 years) aged 24 to 60 years were enrolled. Opisthorchiasis was mainly diagnosed by parasitological assays to detect adult parasite eggs or bodies in duodenal contents and/or feces in all 74 patients. Liver fibrosis was assessed by elastometry according to the METAVIR scale. Functional activity of peripheral blood monocytes was performed in all patients with opisthorchiasis and healthy individuals from the control group by chemiluminescent analysis to measure intensity of reactive oxygen species production in lucigenin- and luminol-dependent spontaneous and zymosan-induced reactions. Results. Liver fibrosis F2 and F3—F4 stage according to METAVIR scale was found in 20.3% and 17.6% of patients with opisthorchiasis, respectively. While analyzing total pool of reactive oxygen species in the luminol-dependent process in patients with opisthorchiasis, a significantly decreased monocyte functional activity was observed as compared to healthy subjects that was evidenced by significantly decreased maximum intensity of produced reactive oxygen species as well as area under the chemiluminescence curve both in spontaneous and zymosan-induced reaction. Such parameters in liver fibrosis F3—F4 compared to F0—F1 in zymosan-induced response were lowered. Monocyte functional activity in spontaneous luminol-dependent reaction did not differ significantly depending on liver fibrosis intensity in patients with opisthorchiasis. The phagocytosis activation index in patients with opisthorchiasis with liver fibrosis F3—F4 compared to F0—F1 and F2 stage was lower. Similar changes were observed in the lucigenin-dependent reaction. Conclusion. The data obtained undoubtedly provide promising evidence to interpret the mechanisms behind liver fibrosis in patients with opisthorchiasis and create new opportunities for development of diagnostic and therapeutic technologies

Comparison of the novel START vascular stiffness index with the CAVI index, assessment of their values and correlations with clinical parameters

Aim. To compare the cardio-ankle vascular index (CAVI) and the novel START vascular stiffness index and assess their values and correlations with clinical parameters.Material and methods. This multicenter study included 928 (403 men and 525 women) randomly selected patients, aged 18 to 89 years (mean age, 41±15,8 years). Inclusion criteria were age over 18 years. There were following exclusion criteria: mental disorder, severe somatic diseases and cancer, contraindications for volume sphygmography using the Fukuda Denshi VS-1500 VaSera system, no patient consent, ankle-brachial index &lt;1,0 and &gt;1,3. Further, according to the main parameters obtained using volum sphygmography, a novel START index was calculated. Comparison of index values and analysis of their correlation with clinical indicators, such as age, systolic blood pressure, diastolic blood pressure, pulse pressure (PP), body mass index and heart rate (HR), were carried out using simple and multiple linear regression, dispersion analysis, calculation of the Pearson coefficient (r), in the software environment R version 4.0.2.Results. Statistical analysis revealed a high correlation between START and CAVI indices (r=0,986, p&lt;0,001). The values of both indices increase significantly with age (ANOVA p&gt;&lt;0,001). Both START and CAVI correlate with all studied clinical parameters. However, in men, there was no relationship of the indices with PP and HR (p&gt;0,05). According to multiple linear regression, the relationship between diastolic blood pressure at the age of 30-60 years and PP at the age of 18-40 years with the START index is more pronounced than with the CAVI index. However, further study of the mathematical model did not reveal a significant difference in the index values for groups with and without high blood pressure.Conclusion. The START vascular stiffness index significantly correlates with the CAVI index, showing no significant differences from CAVI in quantitative relationships with blood pressure, body mass index, heart rate, and sex in various subgroups of the subjects

DEVELOPING OF SUPPORTING PROGRAM FOR OPERATOR OF EXPERIMENTAL NUCLEAR REACTOR

The report describes a program that simplifies the data preparation for the calculation program of the IVK, which allows the calculation of the ИВВ-2М research reactor campaign. The program is implemented using Qt framework and has graphic user interface. The report presents some features of the program.В работе описывается управляющая программа, упрощающая подготовку данных для расчетной программы ИВК, которая позволяет производить расчет кампании исследовательского реактора ИВВ-2М. Программа реализована с помощью фреймворка Qt и имеет графический интерфейс. В докладе приведены некоторые особенности реализации программы

IRRADIATION OF SAMPLES WITH LITHIUM-CONTAINING CERAMICS AND BERYLLIUM-CONTAINING ALLOYS IN THE IVV-2M REACTOR TO STUDY THE KINETICS OF TRITIUM YIELD

The results of Li-comprising ceramics and Be alloys samples irradiation experiment pos-sibility estimation for the purposes of post irradiation examinations and study of tritium re-lease kinetics are presented. The post irradiation examinations aimed to study mechanical properties of materials