Interfacial recombination in In(Al)GaAsSb/GaSb thermophotovoltaic cells

The authors have studied efficient p-on-n homo- (InGaAsSb/GaSb) and heterojunction (InGaAsSb/AlGaAsSb/GaSb) thermophotovoltaic (TPV) cells with respect to the recombination velocity at the cap-layer/emitter interface, S. In both cell types the open-circuit voltage, V{sub oc}, and the short-circuit current, J{sub ac}, have about the same sensitivity to S. The dark current, J{sub 0}, is the most sensitive of all. An examination of the essential factors in the one-dimensional minority-carrier diffusion model shows that under short-circuit conditions, photogenerated electrons diffuse rapidly away from the interface to the junction, whereas under open-circuit conditions, they remain in the emitter for a much longer bulk-recombination time, and therefore, they are more likely to recombine at the interface. A factor of 2.2 increase in S from 5 to 11 {times} 10{sup 4} cm/s produces a 25-mV decrease in V{sub oc}, a 12-% decrease in J{sub ac} or quantum efficiency, and a factor of two increase in J{sub 0}. This work points out the critical importance of interfacial recombination even in efficient TPV cells

Spintronics: Fundamentals and applications

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio

Менингит хантавирусной этиологии

The article describes a clinical case of serous meningitis in a patient with confirmed hemorrhagic fever with renal syndrome (HFRS). Despite the moderate-severe course of the disease with moderate hemorrhagic syndrome, the patient had the development of acute renal failure with the simultaneous occurrence of a rare complication – inflammation of the meningeal membranes caused by hantavirus.Описан клинический случай серозного менингита у пациента при подтвержденной геморрагической лихорадке с почечным синдромом. Несмотря на среднетяжелое течение заболевания с умеренным геморрагическим синдромом, у больного имело место развитие острой почечной недостаточности с одновременным возникновением редкого осложнения – воспаления менингеальных оболочек, вызванного хантавирусом

Экстранодальный рост в метастазах папиллярного рака щитовидной железы – ультразвуковые критерии диагностики и его клиническое значение

The purpose of the research was to identify ultrasound criteria of extranodal extension (ENE) in metastases of papillary thyroid cancer and to evaluate the clinical significance of ENE.Material and Methods. Ultrasound signs of ENE in 283 cervical lymph node metastases from papillary thyroid cancer were analyzed. Extranodal extension in 137 metastases was diagnosed by ultrasound and verified by histological examination. Micrometastases invisible on ultrasound were detected in 144 patients; metastases located inside the organ were detected in 147 patients; metastases located outside the organ were revealed in 136 patients; the size of 98 metastases was less than 1 cm; the size of 185 metastases was more than 1 cm; the age of 51 patients was under 55 years; 132 patients were older than 55 years. Diagnostic significance of ENE and its clinical significance were estimated according to χ2 Pirson criteria.Results: Two ultrasound criteria: shape change and blurred margins of metastases indicated the presence of ENE. The small number of ultrasound false-negative findings indicated the need for further research. The number of micrometastases not detected by ultrasound was 2-fold higher in patients who had metastases with ENE than in patients who had metastases without ENE. The number of patients with ENE in metastases inside the organ (T1a, T1b, T2 and T3b) was 2.7 times lower compared to patients with metastases developed outside the organ (T3a, T4a, T4b); ENE was observed in metastases of different size and did not depend on age groups.Conclusion. The ultrasound method allows intravital detection of ENE in metastases of papillary thyroid cancer. The extension is accompanied by a significantly high number of micrometastases in the neck tissue. It is detected more often in metastases located outside the organ, regardless of the size and age of the patients. The extra-nodal extension should be considered as a criterion for an unfavorable prognosis.Цель исследования – выявить ультразвуковые критерии экстранодального роста в метастазах папиллярного рака щитовидной железы (ПРЩЖ) и оценить его клиническое значение.Материал и методы. Проанализированы ультразвуковые признаки экстранодального роста (ЭР) в 283 метастазах ПРЩЖ в лимфатические узлы шеи. Экстранодальный рост диагностирован ультразвуковым методом в 137 метастазах и верифицирован гистологическим исследованием. Микрометастазы, не определяемые ультразвуковым методом, обнаружены у 144 больных; внутриорганные опухоли установлены у 147 больных; внеорганные – у 136; количество метастазов размером до 1 см – 98, более 1 см – 185; больных моложе 55 лет оказалось 151, старше 55 лет – 132. Диагностическая значимость признаков ЭР и их клиническое значение оценены по критерию χ2 Пирсона.Результаты. Два ультразвуковых критерия – изменение формы и нечеткость контура в метастазе – свидетельствуют об ЭР. Незначительное число ультразвуковых ложноотрицательных данных указывает на необходимость дальнейших исследований. У больных, имеющих метастазы с ЭР, количество микрометастазов в клетчатке шеи, не определяемых ультразвуковым методом, в 2 раза больше по сравнению с больными, у которых метастазы не имеют ЭР. При метастазах с ЭР количество больных с внутриорганным ростом (T1a,T1b,T2 и T3b) в 2,7 раза меньше по сравнению с больными, имеющими опухоли с внеорганным ростом (T3a,T4a,T4b); ЭР в метастазах любых размеров не зависит от возраста больных.Выводы. Ультразвуковой метод позволяет прижизненно выявлять ЭР в метастазах папиллярного рака щитовидной железы. Экстранодальный рост сопровождается значимо большим количеством микрометастазов в клетчатке шеи; он выявляется при внеорганных опухолях; не зависит от размеров и от возраста больных. Экстранодальный рост следует рассматривать как критерий неблагоприятного прогноза

The impact of land use/land cover scale on modelling urban ecosystem services

Context Urbanisation places increasing stress on ecosystem services; however existing methods and data for testing relationships between service delivery and urban landscapes remain imprecise and uncertain. Unknown impacts of scale are among several factors that complicate research. This study models ecosystem services in the urban area comprising the towns of Milton Keynes, Bedford and Luton which together represent a wide range of the urban forms present in the UK. Objectives The objectives of this study were to test (1) the sensitivity of ecosystem service model outputs to the spatial resolution of input data, and (2) whether any resultant scale dependency is constant across different ecosystem services and model approaches (e.g. stock- versus flow-based). Methods Carbon storage, sediment erosion, and pollination were modelled with the InVEST framework using input data representative of common coarse (25 m) and fine (5 m) spatial resolutions. Results Fine scale analysis generated higher estimates of total carbon storage (9.32 vs. 7.17 kg m−2) and much lower potential sediment erosion estimates (6.4 vs. 18.1 Mg km−2 year−1) than analyses conducted at coarser resolutions; however coarse-scale analysis estimated more abundant pollination service provision. Conclusions Scale sensitivities depend on the type of service being modelled; stock estimates (e.g. carbon storage) are most sensitive to aggregation across scales, dynamic flow models (e.g. sediment erosion) are most sensitive to spatial resolution, and ecological process models involving both stocks and dynamics (e.g. pollination) are sensitive to both. Care must be taken to select model data appropriate to the scale of inquiry

Experience in International Cooperation on Organization of Anti-Epidemic Measures by Health Care Institutions under COVID-19 Pandemic in the Republic of Uzbekistan

The results of the joint work of a panel of experts from Rospotrebnadzor and healthcare professionals of the Republic of Uzbekistan on organizing activities to counter the spread of the SARS-CoV-2 virus are described in the paper.The goal of the study was to determine the main driving forces of COVID-19 spread in the Republic of Uzbekistan and develop an action plan to reduce the incidence of coronavirus infection caused by the SARS-CoV-2 virus.Materials and methods. The organization of work in 14 health care institutions in Tashkent and Samarkand, as well as in Tashkent and Samarkand Regions, was analyzed: in 7 laboratories, 6 hospitals and 1 polyclinic. The routes for the movement of personnel, the demarcation of green and red zones, the features of disinfection and the use of personal protective equipment were studied. Attention is drawn to the diagnosis of COVID-19, the use of therapy aimed at reducing the period of virus shedding, the criteria for lifting quarantine restrictions for patients.Results and discussion. The main factors in the organization of work of institutions that contribute to the spread of COVID-19 among medical personnel and the population have been identifed: the lack of equipped gateways between the red and green zones with the accessibility of adequate disinfection, the wrong choice of personal protective equipment, monitoring of contact persons for 10 days, discharge from hospitals based on clinical improvement. The incorrect use of antiviral therapy, the lack of differentiated approaches to the selection of optimal regimens have been noted. Proposals are formulated for organizing the work of healthcare institutions, taking into account the requirements of biological safety. The introduction of targeted measures in addition to those previously adopted has led to a signifcant improvement in the epidemic situation: the total number of active cases in the Republic of Uzbekistan, despite the increase in testing volumes, decreased from 3,686 people on August 23 to 2335 on October 27. Towards December 20, 2020, 97 % of patients recovered completely. All diagnostic triage centers in the Republic of Uzbekistan are closed due to the absence of patients with COVID-19, most of the country’s medical institutions previously re-profled for patients with coronavirus infection have returned to the routine operations

GaSbBi alloys and heterostructures: fabrication and properties

International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures