Note on the stability criteria for a new type of helical flows

In this paper, we proceed exploring the case of non-stationary helical flows of the Navier-Stokes equations for incompressible fluids with variable (spatially dependent) coefficient of proportionality between velocity and the curl field of flow. Meanwhile, the system of Navier-Stokes equations (including continuity equation) has been successfully explored previously with respect to the existence of analytical way for presentation of non-stationary helical flows of the aforementioned type. The main motivation of the current research is the exploring the stability of previously obtained helical flows. Conditions for the stability criteria of the exact solution for the aforementioned type of flows are obtained, for which non-stationary helical flow with invariant Bernoulli-function is considered. As it has been formulated before, the spatial part of the pressure field of the fluid flow should be determined via Bernoulli-function, if components of the velocity of the flow are already obtained.Comment: 10 pages, 1 figures; Keywords: Navier-Stokes equations, non-stationary helical flow, Bernoulli-function; this note corresponds to the article which was accepted for publication in "Journal of King Saud University - Science" (03 July 2018), DOI 10.1016/j.jksus.2018.07.00

Perturbed Rotations of a Rigid Body Close to the Lagrange Case under the Action of Unsteady Perturbation Torques

Perturbed rotations of a rigid body close to the Lagrange case under the action of perturbation torques slowly varying in time are investigated. Conditions are presented for the possibility of averaging the equations of motion with respect to the nutation angle and the averaged system of equations of motion is obtained. In the case of the rotational motion of the body in the linear-dissipative medium the numerical integration of the averaged system of equations is conducted

Non-obvious Problems in Clark Electrode Application at Elevated Temperature and Ways of Their Elimination

Well-known cause of frequent failures of closed oxygen sensors is the appearance of gas bubbles in the electrolyte. The problem is traditionally associated with insufficient sealing of the sensor that is not always true. Study of a typical temperature regime of measurement system based on Clark sensor showed that spontaneous release of the gas phase is a natural effect caused by periodic warming of the sensor to a temperature of the test liquid. The warming of the sensor together with the incubation medium causes oversaturation of electrolyte by dissolved gases and the allocation of gas bubbles. The lower rate of sensor heating in comparison with the medium reduces but does not eliminate the manifestation of this effect. It is experimentally established, that with each cycle of heating of measuring system up to 37 ∘ C followed by cooling the volume of gas phase in the electrolyte (KCl; 60 g/L; 400 L) increased by 0.6 L approximately. Thus, during just several cycles it can dramatically degrade the characteristics of the sensor. A method was developed in which the oxygen sensor is heated in contact with the liquid, (depleted of dissolved gases), allowing complete exclusion of the above-mentioned effect

Актуальные вопросы дифференциальной диагностики острого кашля у детей и взрослых

Cough is one of the most common causes of seeking the primary medical care, especially during the autumn and the spring. This article is a review of literature  aimed at differential diagnosis of possible causes of acute cough in children and  adults. Given a vast majority of diseases associated with cough, differential diagnosis  have to consider several issues. The key issue is cough duration and possible  anatomical location of the pathological changes. An algorithm of differential diagnosis  of acute cough in children and adults and description of most common diseases  associated with acute cough are given in the review. Further diagnostic work-up  should be driven by the duration of cough as soon as the acute cough could be first  manifestation of a chronic disease.Одной из самых частых причин обращения к врачу первичного звена, особенно в осенне-зимний период, является кашель. В свою очередь спектр возможных причин кашля достаточно широк, и для точной диагностики следует использовать ряд принципов, знание которых  облегчит проведение дифференциального диагноза. За основу взят принцип разделения  кашля по длительности проявления и предполагаемой анатомической локализации  патологического процесса. В данном обзоре представлены методика дифференциальной диагностики острого кашля (ОК) у детей и взрослых и разбор частных  патологий, сопровождающихся ОК, с которыми приходится сталкиваться врачу-интернисту.  Установлено, что дальнейший диагностический поиск будет определяться в первую очередь  продолжительностью кашля, т. к. существует вероятность, что ОК является дебютом хронического заболевания

Development of a technology for the preparation of a dry nutrient medium for anthrax vaccine production

Currently, submerged cultivation of the Bacillus anthracis STI-1 strain for live anthrax vaccine production requires liquid nutrient media, which have disadvantages of a short shelf life (no more than one month) and a narrow range of storage temperatures (2–8 °С). Dry media, in contrast, have a number of indisputable advantages: such media are transportable and easy to use, have a standard capability to retain properties, and can be stored without preservatives at 2–30 °С for 2–5 years. The aim of this work was to develop a technology for the preparation of a dry nutrient medium for anthrax vaccine production. Materials and methods: The study used the Bacillus anthracis STI-1 vaccine strain and a nutrient medium for its cultivation, containing a 70:30 mixture of an enzymatic digest of casein and a pre-processed corn extract solution. Drying of the nutrient medium was carried out on a spray-drying unit. The authors evaluated physicochemical parameters of experimental medium batches. The shelf life was determined by an accelerated stability study. The dry nutrient medium was used to produce a live anthrax vaccine. Quality attributes of the vaccine were assessed for compliance with regulatory requirements. Results: The authors developed the dry media production technology. According to it, the liquid nutrient medium is fed to the drying unit at a rate of 20–25 dm3/h. The spray air pressure is 0.02 MPa. Temperatures at the drying chamber inlet and outlet are 118–122 °С and 85–90 °С, respectively. The technology was used to obtain 3 experimental batches of the dry medium. The study results demonstrate that the technology is reproducible, and the tested quality attributes of experimental medium batches are consistent with the requirements. According to the accelerated stability study, the shelf life of the dry nutrient medium at 2–30 °С is at least 3 years. Experiments demonstrated the possibility of using the dry nutrient medium for live anthrax vaccine production. Critical quality attributes of the vaccine obtained with the medium met regulatory requirements. Conclusions: The developed technology allows for the production of a standard dry nutrient medium with a prolonged shelf life, which is convenient for live anthrax vaccine production

Strategies for Abatement of Contamination of Tableted Live Plague Vaccine at Different Stages of Manufacturing

Nowadays, problem of tableted drug form contamination with extraneous micro-flora is in the spotlight of scientists, as the specific share of these medical preparations in the world market amounts to more than 60 % and has a tendency to increase. Thus, objective of the study is to investigate the degree of contamination of the basic and auxiliary raw materials at different stages of live plague vaccine manufacturing, rapid dissolving tablets, and the ways to reduce it. Materials and methods. Utilized has been lyophilized Y. pestis live culture of the vaccine strain EV NIIEG, and the live plague vaccine, rapid dissolving tablets. Carried out has been assessment of “microbiological purity” at different stages of tableted live plague vaccine manufacturing: grinding, mixing, granulation, sublimation, and palletizing. Results and conclusions. Identified is the dynamic pattern of quantitative micro-flora composition of the mentioned above drug. Established is the alteration of microbial impurity at separate technological manufacturing steps. Specified is the technological stage with the most expressed contamination. Analysis of factors, which affect vaccine impurity, has revealed that finished dosage-form quality improvement is impossible without incoming control of stock and auxiliary materials, as well as enhancement of manufacturing procedure up to the level, complying with applicable pharmaceutical production standards. It is experimentally proved that series of tableted live plague vaccine, obtained using modernized technological equipment, provide for 3-fold reduction of contamination

Role of portocaval shunts in development of complications after liver transplantation

Rationale. Portal blood flow is a key component in the viability of the liver transplant. Portocaval shunts formed on the background of the liver cirrhosis before transplantation can cause portal vein steal syndrome, with subsequent development of ischemic necrosis of the graft. To date, the tactics of treating patients with portal vein steal syndrome during liver transplantation has not been sufficiently developed. This paper presents a literature review and our own experience on this important, but little-studied issue. Purpose. The purpose of this research is to study the role of portocaval shunts in the development of complications after liver transplantation, based on a retrospective analysis of clinical cases. Conclusions. In liver transplantation, portocaval shunts can cause the development of portal vein steal syndrome with subsequent development of liver failure. For the diagnosis of portal vein steal syndrome, it is important to use the data obtained at all stages of liver transplantation. Surgical correction of portal vein steal syndrome can be performed during liver transplantation and in the early postoperative period. © 2022 by the authors

НЕСТАЦИОНАРНЫЙ КАПИЛЛЯРНЫЙ ВИСКОЗИМЕТР ДЛЯ КРОВИ

The work is devoted to the development of the theoretical foundations of the processing of measurement results and the algorithm for processing the results for automating measurements for a non-stationary capillary viscometer. The proposed algorithm allows achieving measurement performance and obtaining hemorheological data for diagnostic purposes with a satisfactory degree of accuracy. The results obtained with use of non-stationary capillary viscometer are compared with results achieved with use of rotational viscometer.Работа посвящается разработке теоретических основ обработки результатов измерений и алгоритма обработки результатов для автоматизации измерений для нестационарного капиллярного вискозиметра. Предложенный алгоритм позволяет достичь быстродействия измерений и получить гемореологические данные для диагностических целей с удовлетворительной степенью точности. Приводится сравнение результатов, полученных при использовании нестационарного капиллярного вискозиметра, c результатами, достигнутыми при использовании стандартного ротационного вискозиметра