Impact of axial active magnetic bearing stiffness coefficient on resonance frequencies of reaction wheel rotor

Разработана математическая модель системы «ротор - электромагнитные подшипники» для электродвигателя-маховика системы ориентации и стабилизации космического аппарата. Модель учитывает собственные частоты изгибных колебаний ротора и коэффициенты жесткости электромагнитных подшипников. Предложен способ повышения угловой жесткости системы путем применения многополюсного осевого электромагнитного подшипника и рассмотрено влияние его коэффициента жесткости на собственные частоты системы.The paper presents the mathematical model of «rotor - active magnetic bearings» system for reaction wheel used in spacecraft attitude control system. Developed model consider the natural frequencies of rotor bending oscillations and stiffness parameters of electromagnetic bearing. Method of angular stiffness increasing by using multipolar axial magnetic bearing is suggested and the results of impact analysis of multipolar axial magnetic bearing stiffness on resonance frequencies of system is considered

Assessment of the anionic composition of the soil with the influence of eartworms activity

We established by capillary electrophoresis method that earthworms increase the chloride ion content and reduce the content of sulfate, nitrate and phosphate ions in experimental mesocosm soils. With increasing depth, the concentration of all anions decreases

Internal capsule size associated with outcome in first-episode schizophrenia

Subtle structural brain abnormalities are an established finding in first-episode psychosis. Nevertheless their relationship to the clinical course of schizophrenia is controversially discussed. In a multicentre study 45 first-episode schizophrenia patients (FE-SZ) underwent standardized MRI scanning and were followed up to 1 year. In 32 FE-SZ volumetric measurement of three regions of interests (ROIs) potentially associated with disease course, hippocampus, lateral ventricle and the anterior limb of the internal capsule (ALIC) could be performed. The subgroups of FE-SZ with good (12 patients) and poor outcome (11 patients), defined by a clinically relevant change of the PANSS score, were compared with regard to these volumetric measures. Multivariate analysis of covariance revealed a significant reduced maximal cross sectional area of the left ALIC in FE-SZ with clinically relevant deterioration compared to those with stable psychopathology. There were no differences in the other selected ROIs between the two subgroups. In conclusion, reduced maximal area of ALIC, which can be interpreted as a disturbance of fronto-thalamic connectivity, is associated with poor outcome during the 1 year course of first-episode schizophrenia

Технология сборки и сварки стропильной фермы

Цель работы заключается в разработке технологии сборки и сварки полигональных стропильных ферм и выполнении плана расстановки оборудования в производственном цеху. В результате выполнения выпускной квалификационной работы был определен перечень необходимых операций для производственного цикла, выбран способ сварки, а так же сварочное оборудование, материалы и приспособления, облегчающие сборку. Предложен план расстановки оборудования в производственном цеху. Проведен анализ конкурентоспособности, ресурсоэффективности предлагаемой технологии и анализ вредных и опасных факторов на производстве.The aim of the work is to develop a technology for assembling and welding polygonal rafters and implementing a plan for arranging equipment in the production hall. As a result of the final qualification work, a list of necessary operations for the production cycle was determined, a welding method, as well as welding equipment, materials and devices facilitating assembly was selected. A plan is proposed for arranging equipment in the production shop. The analysis of competitiveness, resource efficiency of the proposed technology and the analysis of harmful and dangerous factors in production are carried out

Cell Origin of Human Mesenchymal Stem Cells Determines a Different Healing Performance in Cardiac Regeneration

The possible different therapeutic efficacy of human mesenchymal stem cells (hMSC) derived from umbilical cord blood (CB), adipose tissue (AT) or bone marrow (BM) for the treatment of myocardial infarction (MI) remains unexplored. This study was to assess the regenerative potential of hMSC from different origins and to evaluate the role of CD105 in cardiac regeneration. Male SCID mice underwent LAD-ligation and received the respective cell type (400.000/per animal) intramyocardially. Six weeks post infarction, cardiac catheterization showed significant preservation of left ventricular functions in BM and CD105+-CB treated groups compared to CB and nontreated MI group (MI-C). Cell survival analyzed by quantitative real time PCR for human GAPDH and capillary density measured by immunostaining showed consistent results. Furthermore, cardiac remodeling can be significantly attenuated by BM-hMSC compared to MI-C. Under hypoxic conditions in vitro, remarkably increased extracellular acidification and apoptosis has been detected from CB-hMSC compared to BM and CD105 purified CB-derived hMSC. Our findings suggests that hMSC originating from different sources showed a different healing performance in cardiac regeneration and CD105+ hMSC exhibited a favorable survival pattern in infarcted hearts, which translates into a more robust preservation of cardiac function

Data on the fate of MACS® MicroBeads intramyocardially co-injected with stem cell products

The data presented in this article are related to the research article “Intramyocardial Fate and Effect of Iron Nanoparticles co-injected with MACS® purified Stem Cell Products” (Müller et al., 2017) [1]. This article complements the cellular localization of superparamagnetic iron dextran particles (MACS® MicroBeads) used for magnetic activated cell sorting (MACS®). Data evaluate the time-dependent detachment of these nanoparticles from CD133+ haematopoietic stem cells (HSCs) and CD271+ mesenchymal stem cells (MSCs). Furthermore, the influence of these stem cells as well as of nanoparticles on cardiac remodeling processes after myocardial infarction (MI) was investigated. Keywords: Stem cell therapy, Cardiovascular regeneration, Haematopoietic stem cells (HSCs), Mesenchymal stem cells (MSCs), Magnetic activated cell sorting (MACS®), MACS® MicroBead

Exploiting AT2R to Improve CD117 Stem Cell Function In Vitro and In Vivo - Perspectives for Cardiac Stem Cell Therapy

Background/Aims: CD117+ stem cell (SC) based therapy is considered an alternative therapeutic option for terminal heart disease. However, controversies exist on the effects of CD117+ SC implantation. In particular, the link between CD117+ SC function and angiotensin-II-type-2 receptor (AT2R) after MI is continuously discussed. We therefore asked whether 1) AT2R stimulation influences CD117+ SC properties in vitro and, 2) which effects can be ascribed to AT2R stimulation in vivo. Methods: We approached AT2R stimulation with Angiotensin II while simultaneously blocking its opponent receptor AT1 with Losartan. CD117 effects were dissected using a 2D-Matrigel assay and HL-1 co-culture in vitro. A model of myocardial infarction, in which we implanted EGFP+ CD117 SC, was further applied. Results: While we found indications for AT2R driven vasculogenesis in vitro, co-culture experiments revealed that CD117+ SC improve vitality of cardiomyocytes independently of AT2R function. Likewise, untreated CD117+ SC had a positive effect on cardiac function and acted cardioprotective in vivo. Conclusions: Therefore, our data show that transient AT2R stimulation does not significantly add to the beneficial actions of CD117+ SC in vivo. Yet, exploiting AT2R driven vasculogenis via an optimized AT2R stimulation protocol may become a promising tool for cardiac SC therapy

CD271+ Human Mesenchymal Stem Cells Show Antiarrhythmic Effects in a Novel Murine Infarction Model

Background: Ventricular arrhythmias (VA) are a common cause of sudden death after myocardial infarction (MI). Therefore, developing new therapeutic methods for the prevention and treatment of VA is of prime importance. Methods: Human bone marrow derived CD271+ mesenchymal stem cells (MSC) were tested for their antiarrhythmic effect. This was done through the development of a novel mouse model using an immunocompromised Rag2−/− γc−/− mouse strain subjected to myocardial “infarction-reinfarction”. The mice underwent a first ischemia-reperfusion through the left anterior descending (LAD) artery closure for 45 min with a subsequent second permanent LAD ligation after seven days from the first infarct. Results: This mouse model induced various types of VA detected with continuous electrocardiogram (ECG) monitoring via implanted telemetry device. The immediate intramyocardial delivery of CD271+ MSC after the first MI significantly reduced VA induced after the second MI. Conclusions: In addition to the clinical relevance, more closely reflecting patients who suffer from severe ischemic heart disease and related arrhythmias, our new mouse model bearing reinfarction warrants the time required for stem cell engraftment and for the first time enables us to analyze and verify significant antiarrhythmic effects of human CD271+ stem cells in vivo