The investigation of hydrogen accumulation in zirconium alloy by thermostimulated gas evolution method

Thermostimulated gas evolution from zirconium alloy saturated by hydrogen E_125 versus deformation degree has been studied. Samples of zirconium were subjected to straining with relative lengthening 2,5; 5,0 and 10,0 %, then they were saturated with hydrogen by electrolyte method at current density 0,5 A/sm2 during 4 hours. Or vice versa, they were first saturated with hydrogen being subjected to deformation afterwards. The deformation of alloy samples results in trap formation with different energies of hydrogen bond. In this case both bond energy and hydrogen quantity caught in traps depends on both deformation size and succession of «deformation-saturation» actions. The values of hydrogen bond energies in traps are estimated. Types of traps are defined

Positron annihilation spectroscopy of vacancy-type defects hierarchy in submicrocrystalline nickel during annealing

Positron annihilation and X-ray diffraction analysis have been used to study submicrocrystalline nickel samples prepared by equal channel angular pressing. In the as-prepared samples the positrons are trapped at dislocation-type defects and in vacancy clusters that can include up to 5 vacancies. The study has revealed that the main positron trap centers at the annealing temperature of deltaT= 20°C-180°C are low-angle boundaries enriched by impurities. At deltaT = 180°C-360°C, the trap centers are low-angle boundaries providing the grain growth due to recrystallization in-situ

Carotid endarterectomy in Russia. What if current guidelines do not answer difficult questions?

This literature review covers the publications of Russian vascular surgeons in recent years and deals with debatable issues of carotid surgery, including: 1. What is the best technique for carotid endarterectomy (CEA)? 2. Why does restenosis of the internal carotid artery (ICA) develop and how to eliminate it? 3. How to operate on bilateral ICA stenosis? 4. Should carotid glomus be preserved? 5. Is CEA safe in the acute phase of cerebrovascular accident (CVA)? 6. Is CEA safe in elderly patients? 7. How to operate on patients with combined internal carotid and coronary artery involvement? The evidence presented in this publication makes it possible to draw the following conclusions: 1. When choosing a CEA technique, the classical technique with patch angioplasty should be avoided due to the high risk of ICA restenosis. 2. To eliminate ICA restenosis, carotid angioplasty with stenting (CAS) should be used. When performing primary CEA with ICA transposition over the hypoglossal nerve, reCEA can be used 3. In the absence of contraindications, bilateral ICA stenosis can be operated at the same time using CEA. 4. CEA with carotid glomus preservation is the operation of choice in the treatment of patients with hemodynamically significant ICA stenosis due to the elimination of the risks of postoperative hypertension and the formation of hemorrhagic transformation. 5. If there are indications for cerebral revascularization in the most acute period of stroke, CEA should be abandoned in favor of CAS. 6. In old age, CAS is the safest treatment strategy. 7. In the presence of a combined ICA and coronary involvement, the choice of treatment tactics should be carried out only by a multidisciplinary commission, taking into account the risk stratification of adverse cardiovascular events

Best Practices of Engineering Training in World Leading Universities

В статье-обзоре освещаются лучшие образовательные практики инженерно-технической подготовки в ведущих зарубежных университетах. Рассматривается современный контекст инженерно-технической подготовки, анализируются ожидания и запросы различных участников образовательного процесса, в том числе представителей промышленности. Основной задачей исследования являлось изучение лучших образовательных практик ведущих зарубежных университетов в области инженерно-технической подготовки, анализ образовательных политик университетов и поддерживающих их реализацию мероприятий. Обсуждаются нововведения в образовательной политике вузов, чей опыт инженерно-технической подготовки определяется новыми задачами реформирования образовательных программ посредством внедрения новых технологий активного, проектного, проблемного обучения с целью формирования у студентов ключевых профессиональных и востребованных межотраслевых профессионально значимых компетенций. Приводятся примеры организации учебного процесса в зарубежных университетах в сотрудничестве с работодателями, а также интегрированная в реальную производственную деятельность подготовка профессорско-преподавательского состава. Выводы авторов относительно изменений современного состояния инженерно-технической подготовки в ведущих зарубежных университетах представлены в рекомендательном ключе с целью возможного пилотирования и интеграции лучших практик в образовательную деятельность по подготовке инженеров в российских университетах.The paper reviews best educational practices in engineering training provided by world leading universities. Modern landscape of engineering training and education has been viewed; expectations and needs of different stakeholders of educational process have been considered, including those of industry representatives. The main purpose of our research is to study the educational practices of the world leading universities in engineering training, to analyze educational policies and training measures supporting their realisation. There are considered the innovations in educational policies of the universities whose experience in engineering training is determined by new objectives of reforming degree programmes via integrating new technologies of active, project-based, and problem-based learning in order to develop students’ key professional competences and generic skills. The examples of curriculum planning in collaboration with employers are viewed. The university staff training integrated into real industry operating is considered. The authors’ conclusions on the changes in the current state of engineering training are presented in the form of advice, with the orientation towards prospective piloting and integration of the best practices into engineering education in Russian universities

Стандартные образцы для градуировки анализатора водорода при высокой концентрации

The study discusses the issues of improving the accuracy of measuring high hydrogen concentrations in the development of storage materials in the hydrogen energy industry. The purpose of the study was to develop reference materials for calibration of the hydrogen analyzers at high concentrations. The main methods for determining the hydrogen content in materials were analyzed. It was established that the extraction method in an inert gas medium has found the widest application. The main methods for determining the hydrogen content in materials are analyzed, it is established that the extraction method in an inert gas medium has found the widest application. The need for calibration of analyzers on reference materials with a high hydrogen concentration was noted. Reference materials of titanium alloy VT-1-0 with hydrogen concentration up to (4.0±0.1) wt.% have been developed. The optimal parameters for the analysis were selected. On the example of the hydrogen analyzer RHEN602 (LECO, USA), calibration was carried out on the developed reference materials to obtain a calibration dependence. The reliability of the obtained calibration curve with the application of stoichiometric zirconium hydride was estimated. The confidence interval of the resulting calibration curve was ±10 %. It has been established that the calibration on the developed materials makes it possible to analyze materials with a hydrogen content of 0.5 to 4.0 wt.%. The practical significance of the study lies in the development of reference materials that can be applied to calibrate hydrogen analyzers operating on the principle of melting in an inert gas medium at a high hydrogen concentration.В данном исследовании рассматриваются вопросы повышения точности при измерении высоких концентраций водорода при разработке материалов-накопителей в водородной энергетике. Цель исследования – разработка стандартных образцов для градуировки анализаторов водорода при высоких концентрациях. Проанализированы основные методы определения содержания водорода в материалах, установлено, что экстракционный метод в среде инертного газа нашел наиболее широкое применение. Отмечена необходимость градуировки анализаторов по стандартным образцам с высокой концентрацией водорода. Разработаны стандартные образцы из титанового сплава ВТ-1-0 с концентрацией водорода до (4,0±0,1) масс.%. Подобраны оптимальные параметры проведения анализа. На примере анализатора водорода RHEN602 (LECO, США) проведена градуировка по разработанным стандартным образцам с получением градуировочной зависимости. Оценена надежность полученной градуировочной прямой с использованием стехиометрического гидрида циркония. Доверительный интервал полученной градуировочной прямой составил ±10 %. Установлено, что проведение градуировки по разработанным образцам позволяет проводить анализ материалов с содержанием водорода от 0,5 до 4,0 масс.%. Практическая значимость исследования заключается в разработке стандартных образцов, которые могут быть применены для проведения градуировки анализаторов водорода, работающих по принципу плавления в среде инертного газа, при высокой концентрации водорода.

СИНТЕЗ И СТРУКТУРА КОМПЛЕКСОВ ХЛОРИДА И БРОМИДА МЕДИ(II) С 4,5-ДИХЛОРИЗОТИАЗОЛ-N-(2-ГИДРОКСИЭТИЛ)-3-КАРБОКСАМИДОМ

Copper(II) chloride and bromide complexes with 4,5-dihlorizotiazol-N-(2-hydroxyethyl)-3-carboxamide (L) with the compositions [CuLHal2 ]n , where Hal = Cl– , Br– , are synthesized. The X-ray analysis revealed that the ligand is coordinated to the copper(II) atoms tridentate by the nitrogen atom of the heterocycle and two exocyclic oxygen atoms to form polymer chains. The copper bromide complex showed a synergistic effect in the compositions of insecticides Kerber and Vitan. Разработаны методики синтеза комплексов галогенидов меди(II) с 4,5-дихлоризотиазол-N-(2-гидрокси- этил)-3-карбоксамидом (L) состава [CuLHal2 ]n , где Hal = Cl– , Br– . Методом рентгеноструктурного анализа установлено, что лиганд координируется к атомам меди(II) тридентатно атомом азота гетероцикла и двумя экзоциклическими атомами кислорода, с образованием полимерных цепочек. Комплекс бромида меди проявил синергический эффект в композициях с инсектицидами Кербер и Витан.

Три наиболее обсуждаемых вопроса каротидной хирургии. Обзор российских и зарубежных исследований последнего пятилетия

This literature review analyzes Russian and foreign publications over the past five years on the three most discussed issues related to carotid artery surgery: 1.Which is more effective: eversion carotid endarterectomy or conventional carotid endarterectomy with patch closure? 2. Which is better: carotid endarterectomy (CEE) or carotid angioplasty and stenting (CAS)? 3. How soon after the development of ischemic stroke should cerebral revascularization be performed?  The authors of the article came to the following conclusions: 1. According to the majority of large studies and meta-analyses, conventional CEE with patch closure is associated with a higher risk of internal carotid artery restenosis compared to eversion carotid endarterectomy. Single-center trials with small samples of patients do not find statistical differences between the outcomes of applying both surgical techniques. 2. Large multicenter randomized trials are required to address the effectiveness of CEA and CAS in symptomatic and asymptomatic patients. To date, there has been no consensus on this matter. 3. CEE and CAS can be equally effective and safe in the most acute and acute periods of ischemic stroke when performed in the presence of a mild neurological deficit and the ischemic brain lesion not exceeding 2.5 cm in diameter. Nevertheless, the choice of treatment strategy should be made strictly personalized by a multidisciplinary council based on the experience of the institution and current recommendations. В настоящем обзоре литературы проведен анализ российских и зарубежных публикаций за последние 5 лет по трем самым обсуждаемым вопросам, связанным с каротидной хирургией: 1. Что более эффективно: эверсионная или классическая техника операции с пластикой зоны реконструкции заплатой? 2. Что оптимальнее: каротидная эндартерэктомия (КЭЭ) или каротидная ангиопластика со стентированием (КАС)? 3. В какие сроки после развития ишемического инсульта следует выполнять реваскуляризацию головного мозга?Авторы статьи пришли к следующим заключениям: 1. По данным большинства крупных исследований и метаанализов классическая КЭЭ с пластикой зоны реконструкции заплатой сочетается с высоким риском развития рестеноза внутренней сонной артерии относительно эверсионной техники операции. Одноцентровые исследования с небольшими выборками больных статистических различий между результатами применения обоих методов операции не находят. 2. Требуется проведение крупных многоцентровых рандомизированных исследований для решения вопросов эффективности КЭЭ и КАС у симптомных и бессимптомных больных. На сегодняшний день единого мнения по этому поводу не выработано. 3. КЭЭ и КАС могут быть одинаково эффективны и безопасны в острейшем и остром периодах ишемического инсульта при реализации в условиях наличия легкого неврологического дефицита и ишемического очага в головном мозге, не превышающего 2,5 см в диаметре. Тем не менее, выбор стратегии лечения должен осуществляться строго персонифицированно мультидисциплинарным консилиумом на основе опыта учреждения и действующих рекомендаций

Long-term outcomes of combined coronary bypass surgery and carotid endarterectomy in patients with type 2 diabetes

At present, there are no studies on the analysis of the incidence of complications in patients with concomitant lesions of the coronary and internal carotid arteries (ICA) after combined operation of carotid endarterectomy (CE) and coronary artery bypass grafting (CABG) against the background of type 2 diabetes (T2D). However, there is no doubt that this condition can be a predictor of cardiovascular and wound complications during in-hospital and long-term postoperative periods.Aim. To study in-hospital and long-term outcomes of combined CABG+CE in patients with and without type 2 diabetes.Material and methods. This multicenter retrospective study for the period from January 2015 to December 2019 included 653 patients with concomitant atherosclerotic lesions of ICA and coronary arteries, who underwent combined CE+CABG. Depending on presence of type 2 diabetes, 2 groups were formed: group 1 (n=183) — patients with type 2 diabetes; group 2 (n=471) — patients without type 2 diabetes. The duration of postoperative follow-up was 37,8±14,9 months.Results. During hospitalization, significant differences in the incidence of death (group 1 =1,1%; group 2 =1,0%; p=0,97), myocardial infarction (MI) (group 1 =1,1%; group 2 =0,8%; p=0,76), bleeding events (group 1 =1,1%; group 2 =0,8%; p=0,76) were not detected. However, stroke (group 1 =3,8%; group 2 =0,4%; p=0,0008), sternal wound infection and mediastinitis (group 1 =3,3%; group 2 =0,2%; p=0,0006) were significantly more often developed in patients with type 2 diabetes.In the long-term follow-up period, death (group 1 =6,6%; group 2 =1,1%; p<0,0001), MI (group 1 =4,9%; group 2 =0,8%; p=0,0008), stroke (group 1 =7,7%; group 2 =1,5%; p<0,0001), ICA restenosis (group 1 =8,8%; group 2 =1,6%; p<0,0001), repeated emergency myocardial revascularization (group 1 =7,2%; group 2 =1,5%; p=0,0002), repeated emergency cerebral revascularization (group 1 =8,8%; group 2 =1,6%; p<0,0001) were significantly more often recorded in patients with type 2 diabetes.Kaplan-Meier curve analysis and its comparison using the log rank test revealed that the death, MI, and stroke were also significantly more often observed in patients with type 2 diabetes (p=0,0007, p=0,003, p<0,0001, respectively).Conclusion. Patients with type 2 diabetes who are referred for combined CE+CABG are at an increased risk of stroke, sternal wound infection and mediastinitis in the in-hospital postoperative period, as well as all adverse cardiovascular events in the long-term follow-up period

Results of thrombectomy in lower-extremity ischemia in patients with COVID-19 and respiratory failure of different severity

Aim. To analyze the results of thrombectomy in lower-extremity ischemia in patients with coronavirus disease 2019 (COVID-19) and respiratory failure of different severity.Material and methods. This retrospective, cohort, comparative study for the period from May 1, 2020 to March 1, 2022 included 305 patients with acute lower-extremity ischemia and COVID-19. Depending on the type of oxygen support, three groups of patients were formed: group 1 (n=168) — nasal oxygen insufflation; group 2 (n=92) — non-invasive ventilation (NIV); group 3 (n=45) — artificial ventilation (AV). Thrombectomy was carried out according to the standard technique using Fogarty catheters (3F-6F — depending on the vessel size). After the diagnosis was established before and after the start of surgical treatment, all patients received the following therapy: Unfractionated IV heparin infusion at an initial rate of 1000 U/r, adjusted to maintain the activated partial thromboplastin time at 2-3 times the normal value; 2. Oral acetylsalicylic acid 125 mg; 3. Analgesics.Results. Myocardial infarction and ischemic stroke were not detected in the total sample. The highest number of deaths (group 1: 5,3%, n=9; group 2: 72,8%, n=67; group 3: 100%, n=45; p<0,0001), retrombosis (group 1 : 18,4%, n=31; group 2: 69,5%, n=64; group 3: 91,1%, n=41; p<0,0001) and limb amputations (group 1: 9,5%, n=16; group 2: 56,5%, n=52; group 3: 91,1%, n=41; p<0,0001) was recorded in group 3 patients.Conclusion. In patients receiving mechanical ventilation, COVID-19 have more aggressive course, which is expressed in an increase in laboratory para- meters (C-reactive protein, ferritin, interleukin-6, D-dimer), the severity of pneumonia and location of thrombosis in the tibial arteries. Among patients with COVID-19 receiving mechanical ventilation, the greatest number of rethromboses (91,1%), limb amputations (91,1%), and deaths (100%) are noted, which suggests the expediency of abandoning open thrombectomy in favor of anticoagulant/antiplatelet therapy in this cohort of patients. The development of arterial thrombosis in patients with COVID-19 receiving mechanical ventilation is an indicator of a high risk of death. Open thrombectomy in combination with anticoagulant/antiplatelet therapy is most effective in patients on nasal oxygen insufflation or NIV