A self-forming nanocomposite concept for ZnO-based thermoelectrics

Zinc oxide (ZnO) has a very broad and versatile range of applications provided by its high abundance and optical and electrical properties, which can be further tuned by donor substitution. Al-doped ZnO is probably the most thoroughly investigated material with regard to thermoelectric properties. Fairly reasonable electrical properties of donor-doped zinc oxide are usually combined with high thermal conductivity limiting potential applications. Here we report a new self-forming nanocomposite concept for ZnO-based thermoelectrics, where a controllable interplay between the exsolution of the nanophases and modification of the host matrix suppresses the thermal transport while imparting enhanced electrical performance. The thermoelectric performance of the best-obtained composite, described by the dimensionless figure-of-merit ZT, at 920-1200 K is almost twice that of the pure matrix composition and reaches up to 0.11. The proposed approach invokes controlled interactions between composite components as a novel tool for decoupling the electrical and thermal transport parameters and shows clear prospects for an implementation in other thermoelectric oxide systems. The results indicate that the proposed concept may also constitute a promising pathway to achieve stable electrical performance at high temperatures, which currently represents one of the major challenges towards achieving ZnO-based thermoelectrics. © The Royal Society of Chemistry

Astrometry and geodesy with radio interferometry: experiments, models, results

Summarizes current status of radio interferometry at radio frequencies between Earth-based receivers, for astrometric and geodetic applications. Emphasizes theoretical models of VLBI observables that are required to extract results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the achievements of VLBI during the past two decades in reference frames, Earth orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys., Vol. 70, Oct. 199

Comparative study of non-invasive force and stress inference methods in tissue

In the course of animal development, the shape of tissue emerges in part from mechanical and biochemical interactions between cells. Measuring stress in tissue is essential for studying morphogenesis and its physical constraints. Experimental measurements of stress reported thus far have been invasive, indirect, or local. One theoretical approach is force inference from cell shapes and connectivity, which is non-invasive, can provide a space-time map of stress and relies on prefactors. Here, to validate force- inference methods, we performed a comparative study of them. Three force-inference methods, which differ in their approach of treating indefiniteness in an inverse problem between cell shapes and forces, were tested by using two artificial and two experimental data sets. Our results using different datasets consistently indicate that our Bayesian force inference, by which cell-junction tensions and cell pressures are simultaneously estimated, performs best in terms of accuracy and robustness. Moreover, by measuring the stress anisotropy and relaxation, we cross-validated the force inference and the global annular ablation of tissue, each of which relies on different prefactors. A practical choice of force-inference methods in distinct systems of interest is discussed.Comment: 12 pages, 8 figures, EPJ E: Topical issue on "Physical constraints on morphogenesis and evolution

A Highly Intensified ART Regimen Induces Long-Term Viral Suppression and Restriction of the Viral Reservoir in a Simian AIDS Model

Stably suppressed viremia during ART is essential for establishing reliable simian models for HIV/AIDS. We tested the efficacy of a multidrug ART (highly intensified ART) in a wide range of viremic conditions (103–107 viral RNA copies/mL) in SIVmac251-infected rhesus macaques, and its impact on the viral reservoir. Eleven macaques in the pre-AIDS stage of the disease were treated with a multidrug combination (highly intensified ART) consisting of two nucleosidic/nucleotidic reverse transcriptase inhibitors (emtricitabine and tenofovir), an integrase inhibitor (raltegravir), a protease inhibitor (ritonavir-boosted darunavir) and the CCR5 blocker maraviroc. All animals stably displayed viral loads below the limit of detection of the assay (i.e. <40 RNA copies/mL) after starting highly intensified ART. By increasing the sensitivity of the assay to 3 RNA copies/mL, viral load was still below the limit of detection in all subjects tested. Importantly, viral DNA resulted below the assay detection limit (<2 copies of DNA/5*105 cells) in PBMCs and rectal biopsies of all animals at the end of the follow-up, and in lymph node biopsies from the majority of the study subjects. Moreover, highly intensified ART decreased central/transitional memory, effector memory and activated (HLA-DR+) effector memory CD4+ T-cells in vivo, in line with the role of these subsets as the main cell subpopulations harbouring the virus. Finally, treatment with highly intensified ART at viral load rebound following suspension of a previous anti-reservoir therapy eventually improved the spontaneous containment of viral load following suspension of the second therapeutic cycle, thus leading to a persistent suppression of viremia in the absence of ART. In conclusion, we show, for the first time, complete suppression of viral load by highly intensified ART and a likely associated restriction of the viral reservoir in the macaque AIDS model, making it a useful platform for testing potential cures for AIDS

Предпосылки развития и меры профилактики компьютерного зрительного синдрома у старшеклассников

Стаття висвітлює результати дослідження, проведеного протягом І семестру 2017–2018 н.р. серед учнів 10–11 класів ЗОШ №19 м. Полтави з метою вивчення передумов розвитку КЗС у старшокласників та пошуку заходів його профілактики. Першим етапом роботи стало стартове анкетування «Ризики для нашого зору», яке передбачало виявлення провідного електронного пристрою, що створює напругу на зір учня, тривалості його використання протягом доби, а також діагностику симптомів КЗС у досліджуваних. Другим етапом дослідження стала апробація системи профілактичних інформаційнопросвітницьких заходів для протидії КЗС та поліпшення зору старшокласників упродовж Місячника турботи про зір. Третім етапом роботи стало фінальне анкетування «Шлях до здорового зору», результати якого обрані в якості критерію ефективності апробованих профілактичних заходів КЗС.The article highlights the results of the research, conducted during the first semester of the 2017–2018 school year among pupils in grades 10–11 of secondary school №19 in Poltava city (Ukraine) in order to study the preconditions for the development of CVS and to search for measures to its prevention. The first stage of this research was the start-up survey «Risks for our vision», aimed at identifying the leading electronic device that creates stress on the pupil’s vision, the duration of its use during the day and also on diagnosing CVS symptoms in testee. The second stage of the research was the approbation of a system of preventive informational and educational measures to counteract the CVS and improve the vision of high school pupils during the Month of Vision Care. The third stage of the work was the final survey «The Path to Healthy Vision», the results of which were selected as a criterion of the effectiveness of approved preventive measures.Статья освещает результаты исследования, проведенного в течение I семестра 2017–2018 учебного года среди учащихся 10–11 классов СШ №19 г. Полтавы с целью изучения предпосылок развития КЗС у старшеклассников и поиска мер его профилактики. Первым этапом работы выступило стартовое анкетирование «Риски для нашего зрения», направленное на выявление ведущего электронного устройства, создающего напряжение на зрение ученика, продолжительности его использования в течение суток, а также на диагностику симптомов КЗС у испытуемых. Вторым этапом исследования была апробация системы профилактических информационно-просветительских мероприятий по противодействию КЗС и улучшению зрения старшеклассников в течение месячника заботы о зрении. Третьим этапом работы стало финальное анкетирование «Путь к здоровому зрению», результаты которого выбраны в качестве критерия эффективности апробированных профилактических мероприятий КЗС