New physical principles of contact thermoelectric cooling

We suggest a new approach to the theory of the contact thermoelectric cooling (Peltier effect). The metal-metal, metal-n-type semiconductor, metal-p-type semiconductor, p-n junction contacts are analyzed. Both degenerate and non-degenerate electron and hole gases are considered. The role of recombination in the contact cooling effect is discussed by the first time.Comment: 8 pages, 8 figures, revtex

The Nature of Thermopower in Bipolar Semiconductors

The thermoemf in bipolar semiconductors is calculated. It is shown that it is necessary to take into account the nonequilibrium distribution of electron and hole concentrations (Fermi quasilevels of the electrons and holes). We find that electron and hole electric conductivities of contacts of semiconductor samples with connecting wires make a substantial contribution to thermoemf.Comment: 17 pages, RevTeX 3.0 macro packag

"Resonance" phenomena in thermal diffusion processes in two-layer structures

The dependence on chopper frequency of the effective thermal diffusivity and effective thermal conductivity in photoacoustic experiments is discussed. The theoretical model of a two-layer structure at rear-surface illumination in the high frequency limit is considered. It is shown that the effective thermal diffusivity presents ``resonance'' while the effective thermal conductivity sharply changes its magnitude and sign. Such ``resonant'' behavior strongly depends on the surface thermal conductivities associated with the interface thermal contacts.Comment: 13 pages, 3 figure

Electron and Phonon Temperature Relaxation in Semiconductors Excited by Thermal Pulse

Electron and phonon transient temperatures are analyzed in the case of nondegenerate semiconductors. An analytical solution is obtained for rectangular laser pulse absorption. It is shown that thermal diffusion is the main energy relaxation mechanism in the phonon subsystem. The mechanism depends on the correlation between the sample length and the electron cooling length in an electron subsystem. Energy relaxation occurs by means of the electron thermal diffusion in thin samples (), and by means of the electron-phonon energy interaction in thick samples (). Characteristic relaxation times are obtained for all the cases, and analysis of these times is made. Electron and phonon temperature distributions in short and long samples are qualitatively and quantitatively analyzed for different correlations between the laser pulse duration and characteristic times.Comment: 33 pages, 16 figure

Анализ связи нарушений гемостаза со степенью выраженности дыхательной недостаточности у пациентов с COVID-19: проспективное наблюдательное исследование

АКТУАЛЬНОСТЬ: Несмотря на прогресс в понимании патофизиологии коагулопатии при COVID-19, сведений о связи и об этапности патологических сдвигов в различных звеньях системы гемостаза при развитии острого респираторного дистресс-синдрома (ОРДС) недостаточно. ЦЕЛЬ ИССЛЕДОВАНИЯ: Определить взаимосвязь тяжести дыхательной недостаточности с патологическими сдвигами в системе гемостаза у больных COVID-19. МАТЕРИАЛЫ И МЕТОДЫ: В проспективное наблюдательное исследование включено 204 больных с верифицированным диагнозом COVID-19 тяжелого и крайне тяжелого течения заболевания. В зависимости от исхода заболевания выделено две группы: группа с летальным исходом (n = 106) и группа выживших больных (n = 98). Для динамической оценки клинической картины заболевания и исследования показателей системы гемостаза определены временные точки: точка I — 1-е сутки, поступление в отделение реанимации и интенсивной терапии (ОРИТ); точка II — 3–5-е сутки; точка III — 7–10-е сутки с момента поступления в ОРИТ. Для оценки тяжести респираторного дистресс-синдрома рассчитывался респираторный индекс. Статистическую обработку данных проводили с использованием пакета статистического программного обеспечения MedCalc Version 20.110 (MedCalc Software Ltd, Бельгия). РЕЗУЛЬТАТЫ: При летальном исходе заболевания COVID-19 тяжелого и крайне тяжелого течения у пациентов определено снижение показателя респираторного индекса в 2,15 раза. Наиболее важные параметры системы гемостаза, влияющие на степень тяжести дыхательной недостаточности: рост концентрации фактора Виллебранда (WF) на точке I исследования (21 % вклада и обратная корреляция), увеличение уровня ингибитора активатора плазминогена 1-го типа (PAI-1) на 3–5-е сутки (35 % вклада и прямая корреляция) и активация коагуляционного звена гемостаза на 7–10-е сутки (78 % вклада и прямая корреляция). ВЫВОДЫ: Степень тяжести дыхательной недостаточности у пациентов с подтвержденным диагнозом COVID-19 тяжелого и крайне тяжелого течения поэтапно связана с эндотелиопатией (1-е сутки), угнетением пристеночного фибринолиза (3–5-е сутки) и активацией коагуляционного звена гемостаза к 7–10-м суткам пребывания в ОРИТ

Wastage amidst shortage: Strategies for the mitigation of standby electricity in residential sector in Nigeria

Abstract : Due to rising population and the increasing rate of urbanization, residential electricity usage accounts for a large chunk of Nigeria’s electricity consumption. However, little attention is paid to electricity conservation in the country. In response to this, several studies are been tailored to ensure a rapid reduction in energy consumption through various alternatives including energy efficient technologies given the current state of inadequate electricity supply in the country. On this note, this article discusses the significance of standby electricity in Nigeria. The electricity generation and consumption patterns were briefly discussed while the current electricity saving behaviour and practices among the urban dwellers were detailed with a case study analysed. Based on the case study, it was discovered that the mean standby load across the 30 households were estimated at 60 W ranging from 34-144 W. Also, standby consumption accounts for 13-44% of the annual electricity consumption across the households. Finally, the strategies for electricity saving and sustainable consumption, most especially the mitigation of standby electricity were highlighted

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

ИССЛЕДОВАНИЕ НЕЙРОРЕТИНОПРОТЕКТОРНОЙ АКТИВНОСТИ ТИОФАНА ПРИ ИНВОЛЮЦИОННОЙ ХОРИОРЕТИНАЛЬНОЙ ДЕГЕНЕРАЦИИ КРЫС ЛИНИИ OXYS

The method of spontaneous and induced luminol -dependent chemiluminescence in homogenates of rat retinas OXYS registered increase in the generation of free radicals against decrease in total antioxidant  activity.  With  the  ultra-microscopic  and  quantitative  analysis  revealed  degenerative retinal neurons rats OXYS: the percentage increase in neurosensory cells with pyknosis of nuclei, hyperchromatic piknomorfnyh associative neurons and ganglion n eurons that have been modified on a light and dark type. Thiophane, limiting free radical reactions in the retina and protects retinal neurons from damage.С помощью метода спонтанной и индуцированной люминолзависимой хемилюминесценции в гомогенатах сетчаток крыс линии OXYS зарегистрировано повышение уровня генерации свободных радикалов на фоне снижения общей антиокислительной активности. С помощью ультрамикроскопического и количественного анализа выявлены дегенеративные изменения нейронов сетчатки крыс линии OXYS: увеличение содержания нейросенсорных клеток с пикнозом ядра, гиперхромных  пикноморфных  ассоциативных нейронов и ганглионарных нейронов, измененных по светлому и темному типу. Установлено, что тиофан, ограничивая свободнорадикальные реакции в сетчатке, защищает нейроны сетчатки от повреждения