Influence of hydrogen on mechanical properties of [012]-crystals of austenitic steel Fe-18Cr-14Ni-2Mo

The influence of hydrogen alloying on critical shear stress, strain hardening coefficient and crystal plasticity depending on temperature of testing in the range of 77...400 К and hydrogen atom concentration has been investigated on monocrystals of austenitic stainless steel Fe-18Cr-14Ni-2Mo with low staking fault energy. Hydrogenation up to 14 at. % is shown to result in 1,5...2 increase of strength properties expressed by temperature dependence of critical shearing strains and to encourage development of local deformation by sliding

Nonlinear dynamical boundary-value problem of hydrogen thermal desorption

The nonlinear boundary-value problem for the diffusion equation, which models gas interaction with solids, is considered. The model includes diffusion and the sorption/desorption processes on the surface, which leads to dynamical nonlinear boundary conditions. The boundary-value problem is reduced to an integro-differential equation of a special kind; existence and uniqueness of the classical (differentiable) solution theorems are proved. The results of numerical experiments are presented

Possible types of the evolution of vacuum shells around the de Sitter space

All possible evolution scenarios of a thin vacuum shell surrounding the spherically symmetric de Sitter space have been determined and the corresponding global geometries have been constructed. Such configurations can appear at the final stage of the cosmological phase transition, when isolated regions (islands) of the old vacuum remain. The islands of the old vacuum are absorbed by the new vacuum, expand unlimitedly, or form black holes and wormholes depending on the sizes of the islands as well as on the density and velocity of the shells surrounding the islands.Comment: 3 pages, 1 figur

Replacement of the aortic valve, ascending aorta and arch in a patient with dextrocardia in the context of situs inversus totalis: a case report

The article discusses a rare case of successful replacement of the aortic valve, ascending  aorta and arch in a patient with dextrocardia  in the context  of situs inversus totalis. Situs inversus is a rare variant of normal anatomy  in which the major visceral organs are mirrored from their normal positions

The use of {99m}Tc-Al[2]O[3] for detection of sentinel lymph nodes in cervical cancer patients

The purpose of the study was to evaluate the feasibility of using {99m}Tc-Al[2]O[3]- based radiopharmaceutical, a novel molecular imaging agent for sentinel lymph node detection in patients with invasive cervical cancer. The study included 23 cervical cancer patients (TlaNxMx- T[2]bNxMx) treated at the Tomsk Cancer Research Institute. At 18 hours before surgery, 80 MBq of the {99m}Tc-Al[2]O[3] were injected peritumorally, followed by single-photon emission computed tomography (SPECT) of the pelvis and intraoperative SLN identification. Twenty-seven SLNs were detected by SPECT, and 34 SLNs were identified by intraoperative gamma probe. The total number of identified SLNs per patient ranged from 1 to 3(the mean number of SLNs was 1.4 per patient). The most common site for SLN detection was the external iliac region (57.2%), followed by the internal iliac, obturator, presacral and retrosacral regions (they amounted to 14%, respectively),and the parametrial region (1%). Sensitivity in detecting SLNs was 100% for intraoperative SLN identification and 79% for SPECT image

Биоразлагаемые упаковочные материалы на основе полиэтилена низкой плотности, крахмала и моноглицеридов

Objectives. To investigate the production and biological degradation of biodegradable hybrid compositions (BHCs), dispersed-filled with starch-containing products of various origins and distilled monoglycerides, along with the biodegradation of compositions based on low density polyethylene and thermoplastic starch (TPS) of various origins: corn, pea, and rice.Methods. Thermoplastic starch was obtained based on native starches of several types, which were processed in Brabender and MashkPlast (Russia) laboratory extruders. BHCs in the form of strands, granules, and films were obtained by mixing thermoplastic starches with polyethylene in extruders. Structural BHC parameters were studied by optical and electron scanning microscopy. The biodegradability of the composite films was evaluated by placing them in biohumus for six months; during storage, the change in water absorption of the films was determined. Before and after the biodegradation process, tensile fracture stress and elongation at rupture were determined to evaluate BHC performance (physical and mechanical characteristics of films). Changes in the chemical structure during biodegradation were determined by Fourier infrared spectroscopy.Results. The positive effect (acceleration of the biodegradation process) of using a novel type of starch plasticizer—monoglycerides distilled in TPS–polyethylene compositions—was confirmed. After six months, intensive sporulation of active microorganisms was observed on the surface of the samples. At the same time, water absorption by the samples reached 30%. The observed 60% decrease in strength and deformation properties indicates an intensive process of biodegradation.Conclusions. The biodegradation rate was shown to depend on the concentration and even distribution of the natural biodegradable filler in the synthetic polymer composition. Цели. Исследовать процесс производства биоразрушаемых гибридных композиций (БГК), дисперсно-наполненных крахмалсодержащими продуктами различного происхождения и дистиллированными моноглицеридами, и их биологическую деструкцию, а также процесс биоразложения композиций на основе полиэтилена низкой плотности и термопластичного крахмала (ТПК) различного происхождения: кукурузного, горохового и рисового.Методы. Термопластичный крахмал получали на основе нативных крахмалов разных видов путем переработки их в лабораторных экструдерах фирм «Брабендер» и «МашПласт» (Россия). Смешивая в экструдерах термопластичные крахмалы с полиэтиленом, получали БГК в виде стренг, гранул и пленок. Структурные параметры БГК изучали методами оптической и электронной сканирующей микроскопии. Способность к биоразложению композитных пленок оценивали, помещая их на полгода в биогумус, и в процессе хранения определяли изменение водопоглощения пленок. Для оценки эксплуатационных свойств (физико-механических характеристик пленок) БГК определяли разрушающее напряжение при растяжении и относительное удлинение при разрыве до и после процесса биоразложения. Изменения химической структуры в процессе биоразложения определяли методом инфракрасной спектроскопии с преобразованием Фурье.Результаты. Подтвержден положительный эффект (ускорение процесса биоразложения) от использования нового типа пластификатора крахмала – дистиллированных моноглицеридов в композициях ТПК–полиэтилен. По истечении полугода на поверхности образцов наблюдали интенсивное спороношение активных микроорганизмов. При этом водопоглощение образцов достигало 30%, прочностные и деформационные свойства снизились на 60%, что свидетельствует об интенсивном протекании процесса биоразложения.Выводы. Установлено, что скорость процесса биоразложения композиций зависит от концентрационного соотношения вводимого ТПК, а также от его равномерного распределения в синтетическим полимере

Surgical treatment of cardiac echinococcosis: a case report

Echinococcosis refers is a chronic disease caused by tapeworms of the order Cyclophyllidea. Echinococcal cysts increase in size slowly and are often asymptomatic, and the symptoms of cardiac echinococcosis are nonspecific, which in turn can make diagnosis difficult. Early diagnosis and surgical treatment of this disease is crucial to prevent severe complications. Considering that the heart is affected extremely rarely, we want to demonstrate the successful surgical treatment