497 research outputs found

    Assembling Di- and Multiatomic Si Clusters in Graphene via Electron Beam Manipulation

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    We demonstrate assembly of di-, tri- and tetrameric Si clusters on the graphene surface using sub-atomically focused electron beam of a scanning transmission electron microscope. Here, an electron beam is used to introduce Si substitutional defects and defect clusters in graphene with spatial control of a few nanometers, and enable controlled motion of Si atoms. The Si substitutional defects are then further manipulated to form dimers, trimers and more complex structures. The dynamics of a beam induced atomic scale chemical process is captured in a time-series of images at atomic resolution. These studies suggest that control of the e-beam induced local processes offers the next step toward atom-by-atom nanofabrication and provides an enabling tool for study of atomic scale chemistry in 2D materials

    Examination of evidence for collinear cluster tri-partition

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    In a series of the experiments at different time-of-flight spectrometers of heavy ions we have observed manifestations of a new at least ternary decay channel of low excited heavy nuclei. Due to specific features of the effect, it was called collinear cluster tri-partition (CCT). The experimental results obtained initiated a number of theoretical articles dedicated to different aspects of the CCT. We compare theoretical predictions with our experimental data, only partially published so far. The model of one of the most populated CCT modes that gives rise to the so called "Ni-bump" is discussed. Detection of the 68-72Ni fission fragments with a kinetic energy E<25 MeV at the mass-separator Lohengrin is proposed for an independent experimental verification of the CCT.Comment: 16 pages, 14 figure

    Evaluation of the elastic properties and topography of leukocytes’ surface in patients with type 2 diabetes mellitus using atomic force microscope

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    The aim of study was to examine some morphometrical parameters (height, diameter) of the leukocytes (white blood cells - WBCs), their specific surface morphology (globular prominences and depression in WBCs) as well as their local elastic properties (Young’s modulus) in healthy persons and in patients with type 2 diabetes mellitus (T2DM) by means of the atomic force microscopy (AFM). Morphological and morphometrical parameters of human leukocytes were evaluated by AFM in tapped mod

    Assessment of the effectiveness of the management of agricultural organizations in management accounting

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    The dynamic development of the agrarian sector of the Russian economy in recent years makes specific demands on agricultural organizations that require a quick response and decision-making based on strategic analytical approaches.Agricultural organizations can achieve the goals previously set during business planning, using reliable information support, tools for analytical actions and competent management decisions. Any managerial decision made in agriculture should be based on timely information analyzed, taking into account cost-effectiveness, practicality, profitability and efficiency. However, it is necessary to evaluate this business in the long term, taking into account the effectiveness of the management of the agricultural organization, for the development of the agricultural organization. In management accounting of agricultural production, the problem of a comprehensive assessment of the effectiveness of the management of an&nbsp;organization (business) is not given attention, and the importance of evaluating a business is also underestimated.The subject of the study is the improvement of management accounting in terms of a comprehensive assessment of the effectiveness of the management of agricultural organizations, based on available accounting documents for external and internal users.The main objective was determined in accordance with the stated goal: to develop recommendations for improving the methodology of management accounting, to assess the effectiveness of management of agricultural organizations.Performance management is an important financial and economic indicator of agricultural production. In this paper, various aspects of management accounting and analysis of the effectiveness of the management of agricultural production are analyzed. It is concluded that the proposed activities will be understood not only by internal users, but also external ones with the help of the developed methodology and management decisions on public documents

    Structure, stability, and mobility of small Pd clusters on the stoichiometric and defective TiO2_2 (110) surfaces

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    We report on the structure and adsorption properties of Pdn_n (n=14n=1-4) clusters supported on the rutile TiO2_2 (110) surfaces with the possible presence of a surface oxygen vacancy or a subsurface Ti-interstitial atom. As predicted by the density functional theory, small Pd clusters prefer to bind to the stoichiometric titania surface or at sites near subsurface Ti-interstitial atoms. The adsorption of Pd clusters changes the electronic structure of the underlying surface. For the surface with an oxygen vacancy, the charge localization and ferromagnetic spin states are found to be largely attenuated owing to the adsorption of Pd clusters. The potential energy surfaces of the Pd monomer on different types of surfaces are also reported. The process of sintering is then simulated via the Metropolis Monte Carlo method. The presence of oxygen vacancy likely leads to the dissociation of Pd clusters. On the stoichiometric surface or surface with Ti-interstitial atom, the Pd monomers tend to sinter into larger clusters, whereas the Pd dimer, trimer and tetramer appear to be relatively stable below 600 K. This result agrees with the standard sintering model of transition metal clusters and experimental observations.Comment: 27 pages, 11 figure

    Evidence that phosphorylation of the alpha-subunit of eIF2 does not essentially inhibit mRNA translation in wheat germ cell-free system.

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    A mechanism based on reversible phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) has been confirmed as an important regulatory pathway for inhibition of protein synthesis in mammalian and yeast cells, while plants constitute the significant exception. We studied the induction of TaeIF2α phosphorylation in germinated wheat (Triticum aestivum) embryos subjected to different adverse conditions. Data confirmed that formation of TaeIF2(αP) was not a general response, as no phosphorylation was observed under salt, oxidative or heat stress. Nevertheless, treatment by salicylic acid, UV-light, cold shock and histidinol did induce phosphorylation of TaeIF2α of wheat, as has been established previously for AteIF2α in Arabidopsis (Arabidopsis thaliana). Influence of TaeIF2α phosphorylation on translation of reporter mRNA with different 5′-untranslated regions (5′UTRs) was studied in wheat germ cell-free system (WG-CFS), in which TaeIF2α was first phosphorylated either by heterologous recombinant human protein kinase, HsPKR (activated by double-stranded (ds)RNA), or by endogenous protein kinase TaGCN2 (activated by histidinol). Pre-treatment of WG-CFS with HsPKR in the presence of dsRNA or with histidinol resulted in intense phosphorylation of TaeIF2α; however, the translation levels of all tested mRNAs decreased by only 10–15% and remained relatively high. In addition, factor OceIF2 from rabbit (Oryctolagus cuniculus) bound GDP much more strongly than the homologous factor TaeIF2 from wheat germ. Furthermore, factor OceIF2B was able to stimulate guanine nucleotides exchange (GDP→GTP) on OceIF2 but had no effect on the similar exchange on TaeIF2. These results suggest that the mechanism of stress response via eIF2α phosphorylation is not identical in all eukaryotes and further research is required to find and study in detail new plant-specific mechanisms that may inhibit overall protein synthesis in plants under stress

    Assessing the Bonding Properties of Individual Molecular Orbitals

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    Molecular orbitals (MOs), while one of the most widely used representations of the electronic structure of a system, are often too complex to intuit properties. Aside from the simplest of cases, it is not necessarily possible to visually tell which orbitals are bonding or antibonding along particular directions, especially in cases of highly delocalized and nontrivial bonding like metal clusters or solids. We propose a method for easily assessing and comparing the relative bonding contributions of MOs, by calculating their response to stress (e.g., compression). We find that this approach accurately describes relative bonding or antibonding character in both the simplest cases and provides new insight in more complex cases. We test the approach on four systems: H2, Am2, benzene, and the Pt4 cluster. In exploring this methodology, a scheme became elucidated, for predicting changes in the ground electronic configuration upon compression, including changes in bonding order, angular momenta of occupied MOs, and trends in MO ordering. We note that the applications of this work go beyond simple molecules and could be straightforwardly extended to, for example, solids and their response to stress along the specific crystallographic plane. Additionally, predictions of structures and properties of chemical systems under stress could result from the emerging intuition about changes in the electronic structure

    Aromaticity in a Surface Deposited Cluster: Pd4_4 on TiO2_2 (110)

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    We report the presence of \sigma-aromaticity in a surface deposited cluster, Pd4_4 on TiO2_2 (110). In the gas phase, Pd4_4 adopts a tetrahedral structure. However, surface binding promotes a flat, \sigma-aromatic cluster. This is the first time aromaticity is found in surface deposited clusters. Systems of this type emerge as a promising class of catalyst, and so realization of aromaticity in them may help to rationalize their reactivity and catalytic properties, as a function of cluster size and composition.Comment: 4 pages, 3 figure

    INFLUENCE OF ETHNIC FEATURES ON ADAPTATION PROCESSES OF A FEMALE ORGANISM IN THE REPRODUCTIVE PERIOD

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    In article resulted data on features of morpho-functional processes in a female organism under the influence of an ethnic factor. It is emphasized that these features are defined by set of genetically caused properties and morpho-functionalsigns of the live systems created according to features of surrounding environment. Results of research of obstetric pathology, growth rates of a fetus, morphometric indeces of women of various ethnic groups are presented. Prospects of the ethnic direction are defined when developing regional standards
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