Secondary electron emission yield in the limit of low electron energy

Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.Comment: 3 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Ital

N-transfer through aspen litter and feather moss layers after fertilization with ammonium nitrate and urea

When fertilizer is broadcast in boreal forest stands, the applied nutrients must pass through a thick layer of either feather moss or leaf litter which covers the forest floor. In a growth chamber experiment we tested the transfer of N through living feather moss or aspen litter when fertilized with urea ((NH2)2CO) or NH4NO3 at a rate of 100 kg ha−1 and under different watering regimes. When these organic substrates were frequently watered to excess they allowed the highest transfer of nutrients through, although 72% of the applied fertilizer was captured in the substrates. In a field experiment we also fertilized moss and aspen litter with urea ((NH2)2CO) or NH4NO3 at a more operationally relevant rate of 330 kg ha−1. We captured the NO3− or NH4+ by ion exchange resin at the substrate–mineral soil interface. In contrast to the growth chamber experiment, this fertilizer rate killed the moss and there was no detectable increase in nutrient levels in the aspen litter or feather moss layers. Instead, the urea was more likely transferred into the mineral soil; mineral soil of the urea treatment had 1.6 times as much extractable N compared to the NH4NO3 treatment. This difference between the growth chamber and field studies was attributed to observed fertilizer- damage to the living moss and possibly damage to the litter microflora due to the higher rate of fertilization in the field. In addition, the early and substantial rainfall after fertilization in the field experiment produced conditions for rapid leaching of N through the organic layers into the mineral soil. In the field, only 8% of the urea-N that was applied was captured by the ion exchange resin, while 34% was captured in for the NH4NO3 fertilization. Thus, the conditions for rapid leaching in the field moved much of the N in the form of urea through the organic layers and into the mineral soil before it was hydrolyzed

About of organization of student science and research works

На примере научной группы профессора Б. В. Шульгина, работающего на кафедре экспериментальной физики, показаны результаты организации НИРС и ВНР студентов в рамках инновационного подхода, осуществляемого путем подключения их к разработке новых объектов интеллектуальной собственности, отвечающих требованиям мировой новизны. В результате такого подхода за последние 40 лет 48 студентов из научной группы профессора Б. В. Шульгина стали соавторами 64 изобретений.The results of student science work organization (including organization of diploma work) on the invention level (creation of new objects of intellectual properties) on the example of science group of professor В. V. Shulgin (experimental physics department) in the frame of innovation way are presented. As a result вгкштп дфые 40 years 48 students from the science group of professor В. V. Shulgin were became co-authors of 64 inventions

Dislocation of the penis: a rare case of genital trauma

Traumatic dislocation of the penis is one of the rarest types of genital trauma. This type of injury is accompanied by a violation of the integrity of the skin and the penile ligamentous apparatus, with the dislocation of the penis into the scrotum under the skin of the thigh, or the area of the pubic joint. The low occurrence frequency of such injuries and the small number of observations described in the literature entails the absence of generally accepted treatment tactics for this category of patients. The article describes a clinical case of successfully treated traumatic dislocation of the penis with penile transposition into the pubic joint area and the formation of subcutaneous urinary leakage after late treatment of the patient for medical care

Фотонные и терагерцовые применения как следующий драйвер рынка арсенида галлия

Analysis of current GaAs and related device market initiated in a number of earlier works has been continued. Binary semiconductor GaAs compound is a conventional MW electronics material. Until recently GaAs based HF ICs for mobile phones were among the most rapidly growing segments of GaAs market. However the GaAs market development trend is changing. Photonics and TeraHertz engineering are becoming the new world GaAs market drivers. This means that the current emphasize of GaAs single crystal technologies will shift toward vertical directional crystallization of “optoelectronic quality” crystals. In the medium and longer terms the world GaAs wafer and epitaxial structure markets will continue growing. In the shorter term we all will have to take into account COVID epidemic consequences. Still the GaAs market is closely related to Smartphone market novelties. Quite probably after a long growth period the GaAs market will keep on shrinking for the second consecutive year: GaAs production may decline by 11–12 % in 2020. Assuming that the epidemic will be somehow taken under control in 2021 the overall Smartphone production can probably be expected to grow starting from 2021.Currently the Russian market of semiconductor compounds for photonics and electronic components (GaAs etc.) is but moderate and in predictable terms is not expected to achieve a level that is required for the emergence of a competitive domestic manufacturer, even though all importation replacement programs are accomplished. Meanwhile there is understanding that developing an advanced electronic components industry in Russia requires larger production of source materials.Продолжен предпринятый ранее в ряде работ анализ современного состояния рынка GaAs и приборов на его основе. Двойное полупроводниковое соединение арсенид галлия (GaAs) — традиционный материал СВЧ-электроники. До недавних пор одним из наиболее быстрорастущих сегментов рынка применений этого материала были высокочастотные интегральные схемы на GaAs для мобильной телефонии. Однако, парадигма развития рынка GaAs меняется. Новым двигателем развития мирового рынка арсенида галлия становится фотоника и терагерцовая техника. Это означает, что в технологиях выращивания монокристаллов GaAs произойдет смена акцентов в сторону кристаллов «оптоэлектронного качества», получаемых методом вертикальной направленной кристаллизации. В средне- и долгосрочной перспективе мировые рынки пластин и эпитаксиальных структур GaAs будут расти. В ближайшей перспективе необходимо учитывать последствия пандемии COVID. Пока рынок GaAs тесно связано с разработками на рынке смартфонов. Очень вероятно, что после длительного периода роста рынок GaAs будет второй год подряд сокращаться — производство GaAs в 2020 году может снизиться на 11—12 %. Если предположить, что пандемия будет как-то взята под контроль в 2021 году, общее производство смартфонов вероятно, вырастет начиная с 2021 г.На данный момент российский рынок полупроводниковых соединений для развития фотоники и электронно-компонентной базы (GaAs и др.) имеет незначительный объем и в ближайшей перспективе не достигнет уровня, необходимого для появления конкурентоспособного отечественного производителя, даже при условии выполнения программ импортозамещения. В то же время, существует понимание, что для создания современной электронной компонентной базы в России необходимо развивать производства исходных материалов

МОЛЕКУЛЯРНО-ГЕНЕТИЧЕСКИЕ ИССЛЕДОВАНИЯ ГЛИАЛЬНЫХ ОПУХОЛЕЙ У ДЕТЕЙ

Glioblastomas are the most frequent malignant neoplasm among primary brain tumors of childhood. Despite the advances in a multimodality treatment approach including neurosurgery, radiotherapy and chemotherapy, the overall survival of such patients remains poor and doesn’t exceed 14 months. The using of targeted agents such as gefitinib in unselected patient populations showed insufficient efficacy. Nowadays, the most perspective approach is a selection of patient populations potentially sensitive to targeted therapy based on predictive markers of response. We performed a comprehensive analysis of the mutational patterns in 30 glioblastomas of children. Data Analysis was based on the new method of mass spectrometry (OncoCarta v1.0, Sequenom) that enabled us to estimate 298 mutations in 19 genes and to identify 10 mutations in 9 tumors (30 %). Mutations were found in BRAF, CDK, HRAS, EGFR, FGFR, MET and PI3K. The most mutated pathway was EGFR – in 20 % of the samples (6/30). The obtained results seem to be very promising in terms of possibilities of using new targeted agents including BRAF inhibitors for treatment of children with glial brain tumors.Глиобластомы у детей представляют собой наиболее частые злокачественные новообразования среди первичных опухолей головного мозга. Несмотря на развитие комплексного лечебного подхода, включающего нейрохирургические, радиотерапевтические и химиотерапевтические методики, общая выживаемость больных с впервые выявленными опухолями остается крайне низкой, не превышая 14 месяцев. При использовании таргетных препаратов, в частности, гефитиниба, в общей популяции больных продемонстрирована низкая клиническая эффективность. Наиболее перспективным в настоящий момент является определение популяции больных, потенциально чувствительных к действию таргетных препаратов, с учетом определения предиктивных молекулярных маркеров. В данной работе определены мутационные изменения в тканях 30 детских глиобластом. Анализ данных, основанный на результатах массспектрометрического секвенирования (OncoCarta v1.0, Sequenom), позволил определить 298 мутаций в 19 генах и идентифицировать 10 мутаций в 9 опухолях (30 %). Изменения выявлены в генах BRAF, CDK, HRAS, EGFR, FGFR, MET и PI3K. Наиболее часто (6/30, 20 % опухолей) мутации выявлены у участников сигнального каскада EGFR. Полученные результаты позволяют говорить о потенциальных возможностях изучения новейших таргетных препаратов, включая ингибиторы BRAF, для лечения больных детского возраста с глиальными опухолями головного мозга

The Study of Species Diversity of Fungi-Litaliano Allocated with Samples of Cement Composites Containing Limestones of Different Origin and Subjected to Aging at Conditions of the Black Sea Climate

The article presents the results of a study of the decay resistance of cement composites filled with carbonate and silicate rocks. The investigated composites exhibited for one year under conditions of the black sea climate in the open air under a canopy of sea coast and sea water. Species and generic diversity of fungi-Litvinov on the samples, depending on the origin of carbonate rocks and the conditions of aging. By results of researches it is stated that fouling, the number of species in the community, as well as specific species composition to a greater extent depends on the operating conditions of the material, and to a lesser extent on the mineral composition of the filler. The authors give a classification of biological agents- destructors of building materials in their preferred conditions of growth that may be promising for the further development of approaches to deal with them. Installed rational compositions of concrete composites derived from limestones of different origin

The ways of enhancement of medical technologies by patients with multitrauma, complicated by urinary tracts inflammation

The condition of immunity status and Theological blood characteristics has been explored in 103 patients (100%) with multitrauma. In 62 cases (60.2%) the possibility of development of the pyelonephritis was increased and in 41 observations (39.8%) for patients we stated the acute pyelonephritis as posttraumatic complication. The immunomodulatory agents (cykloferon and low-molecular heparin - clexan) and the inhibitor of free radical reactions (mexidol) have been used with conventional antibacterial course in complex treatment of patients after injuries. The intake of modified integrated therapy in injured cases allow to decrease the amount of infection inflammatory aftereffects and to improve the results of treatment for patients with acute posttraumatic pyelonephritis.Изучены показатели иммунных и реологических свойств крови у 103 пациентов, перенесших политравму. Вероятность развития пиелонефрита в 62 случаях (60,2%) была высокой, при этом острый пиелонефрит верифицирован в 41 наблюдении (39,8%). При комплексной терапии у больных с политравмой, помимо антибактериальных средств, использован иммуномодуллятор (циклоферон) и низкомолекулярный гепарин (клексан). У больных острым посттравматическим пиелонефритом дополнительно применялся ингибитор свободнорадикальных процессов - мексидол. Модификация схемы комплексного лечения пострадавших позволила снизить частоту инфекционно-воспалительных осложнений и улучшить результаты лечения больных острым посттравматическим пиелонефритом

Proton polarizability effect in the Lamb shift of the hydrogen atom

The proton polarizability correction to the Lamb shift of electronic and muonic hydrogen is calculated on the basis of isobar model and experimental data on the structure functions of deep inelastic lepton-nucleon scattering. The contributions of the Born terms, vector-meson exchanges and nucleon resonances are taken into account in the construction of the photoabsorption cross sections for transversely and longitudinally polarized virtual photons sigma_{T,L}.Comment: 11 pages, 3 figure