134 research outputs found

    Molecular Maps in Cereals: Methodology and Progress

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    Cereals provide for our major food crops, and therefore have been a subject of detailed genetic and cytogenetic studies during major part of the last century. These studies led to the preparation of linkage maps, which were also assigned to individual chromosomes, thus leading to the construction of chromosome maps in all major cereals. In some cases, the availability of cytogenetic stocks (e.g. deletion stocks in bread wheat) also allowed construction of physical maps. In the past, a major limitation in the construction of genetic maps has been the non-availability of mutants for majority of individual genes, so that only handful of genes could be mapped. However, during 1980s, the availability of molecular markers and the high level of DNA polymorphism, which they detect, led to renewed emphasis on genetic and physica.......

    Single nucleotide polymorphisms in rye (Secale cereale L.): discovery, frequency, and applications for genome mapping and diversity studies

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    To elucidate the potential of single nucleotide polymorphism (SNP) markers in rye, a set of 48 barley EST (expressed sequence tag) primer pairs was employed to amplify from DNA prepared from five rye inbred lines. A total of 96 SNPs and 26 indels (insertion–deletions) were defined from the sequences of 14 of the resulting amplicons, giving an estimated frequency of 1 SNP per 58 bp and 1 indel per 214 bp in the rye transcriptome. A mean of 3.4 haplotypes per marker with a mean expected heterozygosity of 0.66 were observed. The nucleotide diversity index (p) was estimated to be in the range 0.0059–0.0530. To improve assay cost-effectiveness, 12 of the 14 SNPs were converted to a cleaved amplified polymorphic sequence (CAPS) format. The resulting 12 SNP loci mapped to chromosomes 1R, 3R, 4R, 5R, 6R, and 7R, at locations consistent with their known map positions in barley. SNP genotypic data were compared with genomic simple sequence repeat (SSR) and EST-derived SSR genotypic data collected from the same templates. This showed a broad equivalence with respect to genetic diversity between these different data types

    ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ ИСПОЛЬЗОВАНИЯ МОНОКРИСТАЛЛИЧЕСКОГО КРЕМНИЯ ПРИ РЕЗКЕ СЛИТКОВ НА ПЛАСТИНЫ

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    The paper presents a comparative analysis pertaining to cutting mono-crystal silicon by a diamond wheel with internal cutting-edge (DWIC) and a multi-stranded tool. It has been shown that in accordance to the output percentage of good plates usage of multi-stranded cutting method is on a par with DWIC; and in accordance to an actual consumption of silicon per one plate the first method exceeds the wheel cutting method. The process of multi-stranded cutting method is characterized by high accuracy, reproducibility, productivity and ensures significant saving of high-priced mono-crystal silicon.Представлены сравнительные результаты использования резки монокристаллического кремния алмазным кругом с внутренней режущей кромкой (АКВР) и  многопроволочной резки. Показано, что по проценту выхода годных пластин использование метода многопроволочной резки не уступает методу резки кругами АКВР, а по фактическому расходу кремния на одну пластину превосходит метод дисковой резки. Процесс многопроволочной резки характеризуется высокой точностью, воспроизводимостью, производительностью и обеспечивает существенную экономию дорогостоящего монокристаллического кремния.

    ФИЗИКО-ХИМИЧЕСКИЕ СВОЙСТВА УЛЬТРАДИСПЕРСНЫХ ПОРОШКОВ КРЕМНИЯ

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    Experimental investigations of ultradispersed silicon powder produced by mechanical grinding are conducted. The process of scaling powders using mechanochemical grinding was studied. It was found that the dimension of crystallites of the silicon powder determines their physical and chemical properties. Finely divided powders of silicon with a particle size ≤10 nm easily decompose water at room temperature into hydrogen and oxygen, they are easily oxidized by air oxygen and actively interact with hydroxides and acids with the release of significant amount of heat. The rate of saturation of micro- and ultradispersed powders with hydrogen at a constant rate of flow in the flow system depends on the temperature of the hydrogen hydrogenation process. It was found that the hydride formed at a low temperature (≤573 K) is in an equilibrium state when it is being hydrogenated in a flow reactor. The treated powder passes into a metastable state with the termination of the thermal action after hydrogenation. Hydrogen, entering the volume of micro- and ultradispersed silicon powder in the temperature range 373–723 K due to the diffusion process, can react not only with silicon atoms to form hydrides of the SiH2 type, but also with hydrides of less active radicals of the type of Si2H4, Si2H6. The hydrogenation process has two distinct stages. It is shown that the temperature of the transition between the stages is determined by the dispersion of micro- and ultradispersed silicon powders and by the structure of hydrides on the particle surface. As a result, it is established that the optimum temperature of hydrogenation should be taken at a temperature of 623 K, at which the maximum mobility of silicon atoms is reached during the formation of hydride. Sharp decrease in the hydrogen content is observed at a temperature above 723 K for the Si2H4 (SiH2).Проведены экспериментальные исследования ультрадисперсного порошка кремния, полученного путем помола полупроводникового монокристаллического кремния, изучен процесс масштабирования порошков с использованием механохимического измельчения. Установлено, что размерность кристаллитов порошков кремния определяет их физико-химические свойства. Ультрадисперсные порошки кремния с размером частиц ≤10 нм легко разлагают воду при комнатной температуре на водород и кислород, они легко окисляются кислородом воздуха и активно взаимодействуют с гидрооксидами и кислотами с выделением значительного количества тепла. Скорость насыщения микро- и ультрадисперсных порошков водородом при постоянной скорости потока в проточной системе зависит от температуры процесса гидрирования водорода. Установлено, что гидрид, образующийся при низкой температуре (≤573 К) находится в равновесном состоянии при гидрировании в проточном реакторе. С прекращением термического воздействия после гидрирования обработанный порошок переходит в метастабильное состояние. Водород, поступающий в объем микро- и ультрадисперсного порошка кремния в диапазоне температур 373–723 К за счет диффузионного процесса, может реагировать не только с атомами кремния с образованием гидридов типа SiH2, но и с гидридами менее активных радикалов типа Si2H4, Si2H6. Процесс гидрирования имеет две явно выраженные стадии. Показано, что температура перехода между стадиями определяется дисперсностью микро- и ультрадисперсных порошков кремния и структурой гидридов на поверхности частиц. В итоге установлено, что за оптимальную температуру гидрирования следует принять температуру 623 К, при которой достигается максимальная подвижность атомов кремния при формировании гидрида. При температуре выше 723 К для гидрида Si2H4 (SiH2) наблюдается резкое уменьшение содержания водорода

    Spatial Structure of <i>Yersinia pestis</i> Population Belonging to Altai Biovar, Subspecies central asiatica Acording to Genome-Wide Sequencing Data

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    The aim of the work was to conduct phylogenetic analysis of Y. pestis strains, biovar altaica ssp. central asiatica, isolated in Gorno-Altai high-mountain and Sailyugem natural plague foci on the territory of Russia and Mongolia in 1965–2020, by full-genome sequencing data.Materials and methods. To determine the population structure of the biovar altaica ssp. central asiatica, 34 whole genome sequences were used (including 20 Y. pestis strains of the biovar altaica, 18 of which were sequenced by us). To isolate DNA from the Y. pestis strains, a PureLink Genomic DNA Mini Kit (Invitrogen, USA) was applied. Sequencing of the nucleotide sequences of Y. pestis strains was carried out in Ion PGM system Lifetechnologies. The analysis and processing of the obtained data were performed with the help of Newblergs Assembler 2.6 and IonTorrent Suite software package, 3.4.2. The search for SNPs was performed using the Wombac 2.0 program. The Maximum Likelihood dendrogram was built in the PhyML 3.1. The dendrogram was visualized using the FigTree 1.4.3 software.Results and discussion. Based on the data of whole genome analysis, taking into account the 1871 revealed polymorphic nucleotides, the spatial structure of the biovar altaica ssp. central asiatica has been determined. It includes several phylogeographic branches: the Kurai-Tarkhatinskaya (cluster 0.PE4a-1) and the Ulandryk-Mongolian (0.PE4a-2), which is in agreement with the geographical regions of the isolation of strains forming these branches in the Altai Mountains. The Kurai-Tarkhatinskaya branch is further divided into the Kurai (sub-cluster 0.PE4a-1-1, formed by the strains of 2009–2018) and Tarkhatinskaya (subcluster 0.PE4a-1-2, formed by the strains of 2012–2020) sub-branches, while the Ulandryk-Mongolian branch of evolution is split into sub-branches represented by strains from the Ulandryk meso focus (sub-cluster 0.PE4a-2-2, strains 1965–2010) and the Sailyugem focus of Mongolia (sub-cluster 0.PE4a-2-1, strains 1964–1990)

    ОПТИЧЕСКИЕ СВОЙСТВА АНОДНОГО ОКСИДА ТИТАНА И ЕГО ПРИМЕНЕНИЕ В ЧЕЛЮСТНО-ЛИЦЕВОЙ ХИРУРГИИ

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    Studying of anodic titania formation has showen that anodization forming factor at low anodic voltages is 3,3 nm/V, while at high anodic voltages it’s value decreases till 1,5 nm/V. The investigation of optical properties of anodic titania has showed the possibilities to tune the titania refractory index in the whole visible ranges. The application of anodic titania in maxillofacial surgery has been demonstrated for visualization of titanium objects.Исследован процесс формирования оксида титана методом электрохимического анодирования. Сформированы пленки плотного оксида титана различных цветов, установлена линейная зависимость толщины пленки оксида от напряжения формовки и параболическая зависимость коэффициента формовки от напряжения формовки. Это определяет оптические свойства образующихся оксидных пленок и возможность управления их коэффициентом отражения во всем видимом оптическом диапазоне. Опробовано использование исследуемых пленок для визуализации и маскирования объектов, используемых в челюстно-лицевой хирургии

    Improvement of Epidemiological Surveillance of Natural Plague Foci of the Russian Federation and the Forecast of Their Epizootic Activity for 2023

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    The aim of the work was to assess the epidemic situation on plague in the world and epizootic activity of natural plague foci of the Russian Federation in 2022. Following the implementation of comprehensive preventive interventions plans, there was a decrease in the epizootic activity of the Gorno-Altai high-mountain and Tuva mountain natural foci, the cessation of plague epizootics in the Central Caucasian high-mountain focus. The total area of epizootics in the Russian Federation in 2022 reached 248.3 km2, which is 7 times less than in 2021. Infected animals were not found in the Tersko-Sunzhensky low-mountain, Dagestan plain-piedmont, Caspian North-Western steppe, Volga-Ural steppe, Trans-Baikal steppe, Volga-Ural sandy, Caspian sandy, East Caucasian high-mountain natural foci. Persistence of tense epizootiological situation in 2023 is predicted for the territory of the Altai Republic and the Republic of Tuva. The prospects of using the GIS portal of the Russian Anti-Plague Institute “Microbe” of the Rospotrebnadzor for an operational assessment of the actual epidemiological situation in natural plague foci are substantiated

    A Case of Human Infection with Plague in the Kosh-Agach Region of the Republic of Altai in 2015. Communication 1. Clinical-Epidemiological and Epizootiological Aspects

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    Objective of the study is to characterize the case of human plague in the territory of Gorno-Altaisk high-mountain natural focus in 2015 and to analyze the initiated measures, associated with localization and elimination of epidemic focus. Materials and methods. Utilized are the data contained in reporting and source (primary) documentation of the FGHI “Altai Plague Control Station”, records of the Rospotrebnadzor Administration in the Republic of Altai, and information collected by the FGHI “Irkutsk Research Anti-Plague Institute”. Results and conclusions. Human infection occurred as a result of gray marmot dressing, which was caught in the Elangash River-Valley, against the background of unfavorable epizootic situation, caused by proliferation of the plague agent of main subspecie in the territory of the focus. Clinical material investigations, performed by means of bacteriological and molecular-genetic methods, showed negative findings. Applying serological method within the system of indirect hemagglutination test (IHAT)/antigen neutralization test (ANT), in blood sera, obtained at the time of hospitalization, low-titred specific antibodies to plague microbe (recognized as post-vaccinal ones) were detected. In blood serum sample, obtained 7 days later, identified were high-titer antibodies, which allowed for confirmation of clinical diagnosis - “bubonic plague”. Due to efficient cooperation between Rospotrebnadzor institutions and medical facilities, as well as municipal authorities it was possible to avoid further development of anthropogenic transmission of plague; to localize and eliminate epidemic outbreak of this dangerous infectious disease in Kosh-Agach Region of the Republic of Altai in the shortest possible time
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