Математическое моделирование влияния вакцинации на распространение эпидемии COVID-19

The mathematical model based on a system of ordinary differential equations is proposed to describe the effect of the vaccination rate on the spread of the COVID-19 epidemic. The results of numerical modeling are presented for the case when vaccination begins after the beginning of the epidemic. A dimensionless vaccination parameter V was obtained, which allows one to characterize the effect of the vaccination rate on the reduction of the incidence of viral diseases with different virulence levels in a large closed population of people. Introducing this parameter allows the simulation results to be generalized to the populations of different size, different epidemic spread rate, different vaccination rate, and different vaccine efficiency. It has been shown that increasing the parameter V decreases the proportion of the sick population. It follows from our model that the vaccination influence on the spread of a respiratory viral disease such as COVID-19 decreases for a later initiation of vaccination. The simulation results should contribute to the development of optimal vaccination scenarios for the population.Предложена математическая модель на основе системы обыкновенных дифференциальных уравнений для описания влияния темпа вакцинации на распространение эпидемии типа COVID-19. Приведены результаты численного моделирования для случая, когда вакцинация начинается после начала распространения эпидемии. Получен безразмерный параметр вакцинации V, который позволяет количественно характеризовать влияние темпа вакцинации на снижение заболеваемости вирусными заболеваниями с различными уровнями вирулентности в большой замкнутой популяции людей. Введение этого параметра позволяет переносить результаты моделирования на популяции других размеров для разных скоростей распространения эпидемии, разных скоростей вакцинирования и разной эффективности вакцин. Показано, что увеличение параметра вакцинации V при прочих равных условиях приводит к снижению доли заболевшего населения. Показано также, что при постоянном темпе вакцинации ее влияние на распространение респираторного вирусного заболевания типа COVID-19 снижается при более позднем начале вакцинации. Результаты моделирования могут способствовать разработке оптимальных сценариев вакцинации населения

СОПРЯЖЕННЫЙ ТЕПЛООБМЕН ПРИ ПОЛУЧЕНИИ СТЕКЛЯННЫХ МИКРОСФЕР В ГАЗОПЛАМЕННОМ РЕАКТОРЕ

A model for the process of glass microsphere production in a recuperative gas-flame reactor was proposed. Based on the described mathematical model of heating and motion of particles in a high-temperature gas stream, which takes into account conjugate heat exchange between the reactor’s operating environment and the recuperator, the appropriate processes were modeled and optimized by geometric and regime parameters. The particle location time in the reactor at a temperature above 1400 °С, which was determined by data of differential scanning colorimetry, was used as an optimized charac- С, which was determined by data of differential scanning colorimetry, was used as an optimized charac- , which was determined by data of differential scanning colorimetry, was used as an optimized characteristic.As a result of optimization calculations, the reactor parameters (diameter and height, natural gas flow rate, air flow rate in the recuperator) were found, as well as regime parameters (diameter and flow rate of glass particles), under which microspheres can be formed. The information obtained can be a basis for designing an effective gas-flame reactor for production of glass microspheres.В работе была предложена модель, описывающая процесс получения стеклянных микросфер в газопламенном реакторе рекуперативного типа. На основе описанной математической модели нагрева и движения частиц в высокотемпературном газовом потоке, учитывающей сопряженный теплообмен между рабочей средой реактора и рекуператором, проведено моделирование и оптимизация соответствующих процессов по геометрическим и режимным параметрам. В качестве оптимизируемой характеристики использовалось время пребывания частиц стекла в реакторе при температуре выше 1400 °С, которое определено на основе данных дифференциальной сканирующей колориметрии.В результате оптимизационных расчетов найдена область параметров реактора (диаметр и высота, расход при-родного газа, расход продуваемого через рекуператор воздуха), а также режимных параметров (диаметр и расход частиц стекла), в которых возможно формирование микросфер. Полученная информация может служить основой для проектирования эффективного газопламенного реактора для получения стеклянных микросфер

Керамоматричный композит из карбида кремния и допированного азотом наноструктурированного углерода для электродов суперконденсаторов

The results of studies on the production of a porous ceramic-matrix composite material C–N/SiC from silicon carbide and nitrogen-doped nanostructured carbon for subsequent use as supercapacitor electrodes are presented. The material is formed by pressing silicon carbide micropowder (1 µm) and impregnating with a solution of carbamide (nitrogen source) in phenol-formaldehyde varnish (carbon source), curing and pyrolysis in a nitrogen atmosphere. The maximum concentration of carbamide was obtained in the solution (16 wt.%) at 50 ºС with a viscosity of 134.3 mPa⋅s. Thermogravimetric analysis in nitrogen of the cured solution revealed multistage decomposition with a residual mass of C–N of 48 % at 1000 ºС. Studies of the elemental composition showed a nitrogen content of 1.4 wt.% in C–N/SiC composite (up to 7 % of C–N active mass). In the composite structure, the C–N carbon-nitrogen layer (up to 12 wt.%) distributed inside the matrix pores and covering the SiC grains is X-ray amorphous has a complex nanoscale relief with an average pore size of 1.0–1.5 nm. According to electrochemical studies, the specific capacitance of the C–N/SiC material and the C–N active layer is 16.84 and 153.2 F/g respectively, and the equivalent resistance of the test supercapacitor cell with C–N/SiC electrodes is 0.567 Ohm for samples with maximum doping. The electrodes operate according to the sorption-desorption mechanism of charge accumulation and release, which is typical for a classic supercapacitor based on a double electric layer without the presence of redox reactions on the electrodes. The influence of technological regimes of pyrolysis on the electrophysical parameters of the cell is revealed: lower values of the pyrolysis temperature and nitrogen pressure in the chamber lead to an increase of the material specific capacitance and reduction of the cell equivalent resistance. The obtained results demonstrate the possibility of utilizing C–N/SiC material for the manufacture of supercapacitor electrodes.Представлены результаты исследований по получению пористого керамоматричного композитного материала C–N/SiC из карбида кремния и допированного азотом наноструктурированного углерода. Материал сформирован посредством прессования микропорошка (1 мкм) карбида кремния и пропитки раствором карбамида (источ ник азота) в фенолформальдегидном лаке (источник углерода), сушки и пиролиза в атмосфере азота. Получена максимальная при 50 °С концентрация карбамида в растворе (16 мас.%) с вязкостью 134,3 мПа·с. Термогравиметрический анализ в азоте высушенного раствора выявил многостадийное разложение с остаточной массой C–N 48 % при 1000 °С. Исследования элементного состава показали содержание азота 1,4 мас.% в композите C–N/SiC (до 7 % от активной массы C–N). В структуре композита углерод-азотный слой C–N (до 12 мас.%), распределенный внутри пор матрицы и покрывающий зерна SiC, является рентгеноаморфным и обладает комплексным наноразмерным рельефом со средним размером пор 1,0–1,5 нм. По данным электрохимических исследований удельная емкость материала C–N/SiC и активного слоя C–N составляет 16,84 и 153,2 Ф/г соответственно, а эквивалентное сопротивление тестовой суперконденсаторной ячейки с электродами C–N/SiC равно 0,567 Ом для образцов с максимальным допированием. Электроды работают по сорбционно-десорбционному механизму накопления и отдачи заряда, что характерно для классического суперконденсатора, работающего на двойном электрическом слое без присутствия окислительно-восстановительных реакций на электродах. Выявлено влияние технологических режимов пиролиза на электрофизические параметры ячейки: более низкие значения температуры пиролиза и давления азота в камере позволяют повысить удельную емкость материала и понизить эквивалентное сопротивление ячейки. Полученные результаты демонстрируют возможность применения C–N/SiC-материала для изготовления электродов суперконденсаторов

Correlation effects during liquid infiltration into hydrophobic nanoporous mediums

Correlation effects arising during liquid infiltration into hydrophobic porous medium are considered. On the basis of these effects a mechanism of energy absorption at filling porous medium by nonwetting liquid is suggested. In accordance with this mechanism, the absorption of mechanical energy is a result expenditure of energy for the formation of menisci in the pores on the shell of the infinite cluster and expenditure of energy for the formation of liquid-porous medium interface in the pores belonging to the infinite cluster of filled pores. It was found that in dependences on the porosity and, consequently, in dependences on the number of filled pores neighbors, the thermal effect of filling can be either positive or negative and the cycle of infiltration-defiltration can be closed with full outflow of liquid. It can occur under certain relation between percolation properties of porous medium and the energy characteristics of the liquid-porous medium interface and the liquid-gas interface. It is shown that a consecutive account of these correlation effects and percolation properties of the pores space during infiltration allow to describe all experimental data under discussion

A multiplatform approach identifies miR-152-3p as a common epigenetically regulated onco-suppressor in prostate cancer targeting TMEM97

Prostate cancer (PCa) is a major cause of morbidity and mortality in men worldwide. MicroRNAs are globally downregulated in PCa, especially in poorly differentiated tumors. Nonetheless, the underlying mechanisms are still elusive. Herein, using combined analysis of microRNAs expression and genomewide DNA methylation, we aimed to identify epigenetically downregulated microRNAs in PCa.Research Center of Portuguese Oncology Institute of Porto (FB-GEBC-27 and 19-CI-IPOP-2016). JR-C and CSG are supported by FCT- Fundação para a Ciência e Tecnologia PhD fellowships (SFRH/BD/71293/2010 and SFRH/BD/92786/2013), SS is supported by a PhD fellowship IPO/ESTIMA-1 NORTE-01-0145-FEDER-000027, and IG is a research fellow from the strategic funding of FCT (PCT: PEst- UID/DTP/00776/2013 and COMPETE: POCI-01-0145-FEDER-006868). BMC is funded by FCT-Fundação para a Ciência e a Tecnologia (IF/00601/2012)info:eu-repo/semantics/publishedVersio

Мультимодальний підхід при реконструкції вогнепальних дефектів м'яких тканин передпліччя та зап'ястку

According to the literature, gunshot extremities wounds are most frequent among combat trauma and affect up to 62.2% of the patients. The total rate of gunshot upper extremities wounds is high too – near of 25.7% [1], in particular during local military conflicts. Provision of effective medical tactics allow to return the serviceman to service and expand the reserve of experienced personnel in Armed Forces. The forearm–hand area has a high functional value. It contains a large number of mobile anatomical elements, the complex structure of connective tissue, vascular and nervous structures. In this regard, the treatment of damage to this area is a significant clinical problem that requires a long and hard work. At the same time, active surgical tactics to accelerate the restoration of anatomical – functional integrity of the upper extremity [1–9] is necessary, as the complexity and fragility of the anatomical structure cause significant limitation of hand function even due to minor, at first glance, scarring

Identification and Pathway Analysis of microRNAs with No Previous Involvement in Breast Cancer

microRNA expression signatures can differentiate normal and breast cancer tissues and can define specific clinico-pathological phenotypes in breast tumors. In order to further evaluate the microRNA expression profile in breast cancer, we analyzed the expression of 667 microRNAs in 29 tumors and 21 adjacent normal tissues using TaqMan Low-density arrays. 130 miRNAs showed significant differential expression (adjusted P value = 0.05, Fold Change = 2) in breast tumors compared to the normal adjacent tissue. Importantly, the role of 43 of these microRNAs has not been previously reported in breast cancer, including several evolutionary conserved microRNA*, showing similar expression rates to that of their corresponding leading strand. The expression of 14 microRNAs was replicated in an independent set of 55 tumors. Bioinformatic analysis of mRNA targets of the altered miRNAs, identified oncogenes like ERBB2, YY1, several MAP kinases, and known tumor-suppressors like FOXA1 and SMAD4. Pathway analysis identified that some biological process which are important in breast carcinogenesis are affected by the altered microRNA expression, including signaling through MAP kinases and TP53 pathways, as well as biological processes like cell death and communication, focal adhesion and ERBB2-ERBB3 signaling. Our data identified the altered expression of several microRNAs whose aberrant expression might have an important impact on cancer-related cellular pathways and whose role in breast cancer has not been previously described

Identification of Pax6-Dependent Gene Regulatory Networks in the Mouse Lens

Lineage-specific DNA-binding transcription factors regulate development by activating and repressing particular set of genes required for the acquisition of a specific cell type. Pax6 is a paired domain and homeodomain-containing transcription factor essential for development of central nervous, olfactory and visual systems, as well as endocrine pancreas. Haploinsufficiency of Pax6 results in perturbed lens development and homeostasis. Loss-of-function of Pax6 is incompatible with lens lineage formation and results in abnormal telencephalic development. Using DNA microarrays, we have identified 559 genes expressed differentially between 1-day old mouse Pax6 heterozygous and wild type lenses. Of these, 178 (31.8%) were similarly increased and decreased in Pax6 homozygous embryonic telencephalon [Holm PC, Mader MT, Haubst N, Wizenmann A, Sigvardsson M, Götz M (2007) Loss- and gain-of-function analyses reveals targets of Pax6 in the developing mouse telencephalon. Mol Cell Neurosci 34: 99–119]. In contrast, 381 (68.2%) genes were differently regulated between the lens and embryonic telencephalon. Differential expression of nine genes implicated in lens development and homeostasis: Cspg2, Igfbp5, Mab21l2, Nrf2f, Olfm3, Spag5, Spock1, Spon1 and Tgfb2, was confirmed by quantitative RT-PCR, with five of these genes: Cspg2, Mab21l2, Olfm3, Spag5 and Tgfb2, identified as candidate direct Pax6 target genes by quantitative chromatin immunoprecipitation (qChIP). In Mab21l2 and Tgfb2 promoter regions, twelve putative individual Pax6-binding sites were tested by electrophoretic mobility shift assays (EMSAs) with recombinant Pax6 proteins. This led to the identification of two and three sites in the respective Mab21l2 and Tgfb2 promoter regions identified by qChIPs. Collectively, the present studies represent an integrative genome-wide approach to identify downstream networks controlled by Pax6 that control mouse lens and forebrain development

Высокотеплопроводная карбидокремниевая керамика для крупногабаритной космической оптики

The paper describes the important aspects of the developed technology for manufacturing silicon-carbide substrates for optical mirrors intended for future use in space applications. It is shown that the material with the best combination of thermophysical and mechanical properties (Maksutov’s criterion) among the known analogs used for making astronomical mirrors is obtained. The characteristics of a mirror made of a lightweight mirror substrate with a diameter of 205 mm are described, compared with the parameters of most known mirrors made of silicon carbide for various space missions and as proto types. It is shown that the produced substrate is characterized by a rather low specific gravity – 16.5 kg/m2, which is comparable with the indicators of the best world analogues.Описаны важные аспекты разработанной технологии изготовления карбидокремниевых подложек для оптических зеркал, предназначенных для перспективного использования в космических приложениях. Показано, что получен материал с лучшим сочетанием теплофизических и механических свойств (критерий Максутова) среди известных аналогов, применяемых при создании астрономических зеркал. Описаны характеристики изготовленной из него облегченной подложки зеркала диаметром 205 мм, проведено сравнение с параметрами большинства известных зеркал, изготовленных из карбида кремния для различных космических миссий и в качестве опытных образцов. Показано, что изготовленная подложка характеризуется низкой удельной массой – 16,5 кг/м2, что сопоставимо с показателями лучших мировых аналогов