Применение импульсного тока для растворения жаропрочного сплава ЖС32-ВИ

Objectives. To identify the regularities of electrochemical processing of the heat-resistant GS32-VI alloy in a sulfuric acid electrolyte with a concentration of 100 g/dm3 under the action of a pulsed current in a pulsed mode.Methods. Using the electrochemical technological complex EHK-1012 (developed by IP Tetran) and a non-compensatory method of measuring potential, polarization and depolarization curves with a change in pulse duration and a pause between them were recorded. The current pulses had an amplitude ranging from 0 to 3.5 A (when recording the polarization and depolarization curves), pulse durations ranging from 200 to 1200 ms, and a pause (delay) between pulses ranging from 50 to 500 ms. There were no reverse current pulses.Results. The parameters of the current program that provide the maximum values of the alloy dissolution rate and current output were determined: with a current pulse amplitude of 2 A, a current pulse duration of 500 ms, and a pause duration between pulses of 250 ms, the maximum dissolution rate of the alloy is 0.048 g/h·cm2, while the current output for nickel is 61.6% with an anode area of 10 cm2. The basic technological scheme for processing the heat-resistant GS32-VI alloy, which includes anodic alloy dissolution in a pulsed mode, is proposed.Conclusions. Electrochemical dissolution of GS32-VI alloy under pulsed current action results in an optimal dissolution rate ratio of the alloy components, ensuring the production of a cathode precipitate with a total nickel and cobalt content of 97.5%.Цели. Выявить закономерности электрохимической переработки жаропрочного сплава ЖС32-ВИ, проводимой в импульсном режиме в сернокислом электролите с концентрацией 100 г/дм3 под действием импульсного тока.Методы. Снятие поляризационных и деполяризационных кривых с изменением длительности импульса и паузы между ними проводили с помощью электрохимического технологического комплекса ЭХК-1012 (разработан ООО ИП «Тетран»), использующего некомпенсационный способ измерения потенциала. Амплитуда импульсов тока находилась в диапазоне значений от 0 до 3.5 А (при снятии поляризационных и деполяризационных кривых), длительности импульсов изменялись от 200 до 1200 мс, пауза (задержка) между импульсами – от 50 до 500 мс, импульсы реверсивного тока отсутствовали.Результаты. Определены параметры токовой программы, обеспечивающие максимальные значения скорости растворения сплава и выхода по току. При амплитуде импульса тока 2 А, длительности импульса тока 500 мс и продолжительности паузы между импульсами 250 мс максимальная скорость растворения сплава 0.048 г/ч·см2, при этом выход по току для никеля равен 61.6% при площади анода 10 см2. Предложена принципиальная технологическая схема переработки жаропрочного сплава ЖС32-ВИ, включающая анодное растворение сплава в импульсном режиме.Выводы. Электрохимическое растворение сплава ЖС32-ВИ под действием импульсного тока способствует оптимальному соотношению скоростей растворения составляющих сплава, что обеспечивает получение катодного осадка с суммарным содержанием никеля и кобальта 97.5%

Shortterm and long-term results of bimammary bypass surgery in patients with multivessel coronary disease and type 2 diabetes mellitus after propensity score matching

Background. Among patients who have undergone coronary artery bypass surgery (CABG), the proportion of people with diabetes mellitus (DM) is about 40 %. To date, the problem of choosing the optimal method of surgical myocardial revascularization, which can provide the best result in this cohort, remains completely unresolved. The aim of the study. To assess the in-hospital and long-term results of bimammary and traditional bypass surgery in patients with type 2 diabetes mellitus. Methods. From September 2018 to December 2021, 176 CABG surgeries were performed in patients with coronary heart disease (CHD) and type 2 diabetes at the Federal Center for Cardiovascular Surgery (Krasnoyarsk). Group 1 (n = 45) included patients who underwent myocardial revascularization using two mammary arteries; group 2 (n = 131) included patients who underwent myocardial revascularization using traditional technique. After propensity score matching, 45 patients were selected into each group, comparable by basic preoperative characteristics. Results. In group  1, cardiopulmonary bypass surgeries were performed in 23 (51.1 %) patients (group 1CPB), off-pump surgeries – in 22 (58.2 %) (group 1OP); in group  2, all patients underwent cardiopulmonary bypass surgeries. Hospital mortality was recorded in group 2 in 1 (2.2 %) case. Deep sternal infection developed in 1 (4.5 %) patient in group 1OP. Long-term survival in group 2 was 85.3 %, in group 1CPB – 83.3 % (p = 0.689), in group 1OP – 84.2 % (p = 0.739). 84.2 % of patients in group 2 and 100 % in groups 1CPB and 1OP had no cardiovascular events (p = 0.144 and p = 0.145, respectively). Conclusion. Bimammary bypass surgery in patients with type 2 diabetes is a safe and effective method of surgical treatment of coronary artery disease in both shortand long-term period and may be the operation of choice in patients with multivessel disease. There were no differences in patient survival up to 45 months; bimammary revascularization was associated with 100 % absence of cardiac mortality

ИССЛЕДОВАНИЕ ВЗАИМОДЕЙСТВИЯ ЭЛЕКТРОМАГНИТНОГО ИЗЛУЧЕНИЯ С МАТЕРИАЛАМИ НА ОСНОВЕ ХРИЗОТИЛОВЫХ АСБЕСТОВ

The research results of radioabsorbing composite materials based on chrysotile asbestos electromagnetic radiation reflection and attenuation characteristics in the frequency range 2...18 GHz are studied. The expediency of use of these materials for manufacturing of wide screens EME is shown.Приводятся результаты исследований характеристик отражения и ослабления электромагнитного излучения в диапазоне частот 2…18 ГГц радиопоглощающими композиционными материалами на основе хризотиловых асбестов. Показана целесообразность использования этих материалов для изготовления широкодиапазонных экранов ЭМИ

Cardiac tumors: analysis of surgical treatment

Aim. To analyze the preoperative status, intraoperative tumor characteristics and further clinical manifestations in patients after surgery for a cardiac tumor.Material and methods. The study included 54 patients who were operated on for a heart tumor from 2014 to 2020. We assessed clinical performance, diagnostic investigations before and after (during hospitalization) surgery, tumor size and histological characteristics.Results. Among patients operated on for cardiac tumors, women predominated (74%). Among comorbidities, hypertension (79,3%), chronic kidney disease (48,3%), and obesity (25,9%) were most common. There were following clinical manifestations before surgery: shortness of breath — 47 (81%) patients, palpitations and heart rhythm disturbance — 26 (44,8%), chest pain — 25 (43,1%), chest discomfort — 28 (49,1%), edema — 6 patients (10,3%). The predominant tumor localization was the left atrial fossa ovalis area (50%). According to histological analysis, myxoma prevailed — 38 cases (86,4%). After surgery, atrial fibrillation prevalence decreased from 8 patients before surgery to 6 after surgery (p=0,034), while left atrial size decreased by 0,6 mm (95% confidence interval, 4,39-6,2 mm) (p<0,001).Conclusion. According to presented analysis over a 6-year period, cardiac neoplasms are more common in women (74,1%), while the mean age of patients is 59,7 years. Among comorbidities, hypertension prevails — 79,3%. Histological examination revealed a predominance of myxoma (86,4%). Predominant tumor location was the left atrial fossa ovalis area (50%). Surgical treatment of neoplasms was effective. So, prevalence of atrial fibrillation decreased by 25%, while left atrial size decreased by 0,6 mm. Postoperative complications and in-hospital deaths were not registered

The MoS2 Nanotubes with Defect-Controlled Electric Properties

We describe a two-step synthesis of pure multiwall MoS2 nanotubes with a high degree of homogeneity in size. The Mo6S4I6 nanowires grown directly from elements under temperature gradient conditions in hedgehog-like assemblies were used as precursor material. Transformation in argon-H2S/H2 mixture leads to the MoS2 nanotubes still grouped in hedgehog-like morphology. The described method enables a large-scale production of MoS2 nanotubes and their size control. X-ray diffraction, optical absorption and Raman spectroscopy, scanning electron microscopy with wave dispersive analysis, and transmission electron microscopy were used to characterize the starting Mo6S4I6 nanowires and the MoS2 nanotubes. The unit cell parameters of the Mo6S4I6 phase are proposed. Blue shift in optical absorbance and metallic behavior of MoS2 nanotubes in two-probe measurement are explained by a high defect concentration

Advances in Targeting Signal Transduction Pathways

Over the past few years, significant advances have occurred in both our understanding of the complexity of signal transduction pathways as well as the isolation of specific inhibitors which target key components in those pathways. Furthermore critical information is being accrued regarding how genetic mutations can affect the sensitivity of various types of patients to targeted therapy. Finally, genetic mechanisms responsible for the development of resistance after targeted therapy are being discovered which may allow the creation of alternative therapies to overcome resistance. This review will discuss some of the highlights over the past few years on the roles of key signaling pathways in various diseases, the targeting of signal transduction pathways and the genetic mechanisms governing sensitivity and resistance to targeted therapies

Disruption of the Lipid-Transporting LdMT-LdRos3 Complex in Leishmania donovani Affects Membrane Lipid Asymmetry but Not Host Cell Invasion

Maintenance and regulation of the asymmetric lipid distribution across eukaryotic plasma membranes is governed by the concerted action of specific membrane proteins controlling lipid movement across the bilayer. Here, we show that the miltefosine transporter (LdMT), a member of the P4-ATPase subfamily in Leishmania donovani, and the Cdc50-like protein LdRos3 form a stable complex that plays an essential role in maintaining phospholipid asymmetry in the parasite plasma membrane. Loss of either LdMT or LdRos3 abolishes ATP-dependent transport of NBD-labelled phosphatidylethanolamine (PE) and phosphatidylcholine from the outer to the inner plasma membrane leaflet and results in an increased cell surface exposure of endogenous PE. We also find that promastigotes of L. donovani lack any detectable amount of phosphatidylserine (PS) but retain their infectivity in THP-1-derived macrophages. Likewise, infectivity was unchanged for parasites without LdMT-LdRos3 complexes. We conclude that exposure of PS and PE to the exoplasmic leaflet is not crucial for the infectivity of L. donovani promastigotes

МУЛЬТИСПИРАЛЬНАЯ КОМПЬЮТЕРНАЯ ТОМОГРАФИЯ В ДИАГНОСТИКЕ ПАТОЛОГИИ ДУГИ АОРТЫ И АНОМАЛИЙ БРАХИОЦЕФАЛЬНЫХ АРТЕРИЙ У ДЕТЕЙ ПЕРВОГО ГОДА ЖИЗНИ

Aortic malformations often cause critical states in the neonatal period. MSCT method allows you to get a detailed understanding of the anatomy of vice and identify concomitant bronchopulmonary disease. This paper presents a comparative analysis of 27 patients of the first year of life with the pathology of the aortic arch, which were performed echocardiography and MSCT. After analysis of both research methods in 4 patients revealed a discrepancy echocardiography and MSCT data which led to a change in surgical approach. Just according to SITC 2 patients revealed tracheal stenosis, in one case, isolated, in another due to compression of the vascular ring. MSCT is a highly informative method for diagnosing pathology of the aortic arch and associated bronchopulmonary disease in children in the first year of life.Пороки развития аорты зачастую являются причиной критических состояний в неонатальном периоде. Метод МСКТ позволяет получить детальное представление об анатомии порока и выявить сопутствующую бронхолегочную патологию. В работе представлен сравнительный анализ данных 27 пациентов первого года жизни с патологией дуги аорты, которым была выполнена ЭхоКГ и МСКТ. После анализа обоих методов исследования у 4 пациентов выявлено несоответствие данных ЭхоКГ и МСКТ, что привело к изменению хирургической тактики. Также по данным МСТК, у 2 пациентов выявлен стеноз трахеи, в одном случае - изолированный, в другом - за счет сдавления сосудистым кольцом. МСКТ является высокоинформативным методом диагностики патологии дуги аорты и сопутствующей бронхолегочной патологии у детей первого года жизни