244 research outputs found

    Dynamics of quantum systems

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    A relation between the eigenvalues of an effective Hamilton operator and the poles of the SS matrix is derived which holds for isolated as well as for overlapping resonance states. The system may be a many-particle quantum system with two-body forces between the constituents or it may be a quantum billiard without any two-body forces. Avoided crossings of discrete states as well as of resonance states are traced back to the existence of branch points in the complex plane. Under certain conditions, these branch points appear as double poles of the SS matrix. They influence the dynamics of open as well as of closed quantum systems. The dynamics of the two-level system is studied in detail analytically as well as numerically.Comment: 21 pages 7 figure

    Studies of Immunobiological Properties in <i>Francisella tularensis</i> Vaccine Strain 15 NIIEG under Extended Storage Conditions

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    Investigated have been 8 cultures of Francisella tularensis strain 15 NIIEG (lyophilized in 1953, 1966, 1969, 1987, 1990, 2003, 2012, and 2013, respectively) stored at the State Collection of Microorganisms of the Scientific Center on Expertise of Medical Application Products. It is established that the majority of cultures has maintained their immunobiological properties. However, it is of note that liophilization does not prevent F. tularensis strain 15 NIIEG from changes in its residual virulence under extended storage. Revealed is the fact that LD50 for 7 cultures of tularemia microbe strain is within the limits of 100-250 microbial cells (m.c.). At the same time, residual virulence for the strain which dates back 1966 is 7.3·105 m.c. Immunogenic activity rates in F. tularensis 15 NIIEG strain cultures range within specified limits. Apart from this, F. tularensis 1987 strain does not comply with the established requirements to the “specific safety”, as subcutaneous inoculation with 5·109 m.c./ml caused death of Guinea pigs within the scheduled observation time. Demonstrated is the necessity in maintaining constant stability of the original immunobiological properties in Francisella tularensis strain 15 NIIEG under extended storage conditions

    Non-sequential double ionization below laser-intensity threshold: Anticorrelation of electrons without excitation of parent ion

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    Two-electron correlated spectra of non-sequential double ionization below laser-intensity threshold are known to exhibit back-to-back scattering of the electrons, viz., the anticorrelation of the electrons. Currently, the widely accepted interpretation of the anticorrelation is recollision-induced excitation of the ion plus subsequent field ionization of the second electron. We argue that another mechanism, namely simultaneous electron emission, when the time of return of the rescattered electron is equal to the time of liberation of the bounded electron (the ion has no time for excitation), can also explain the anticorrelation of the electrons in the deep below laser-intensity threshold regime. Our conclusion is based on the results of the numerical solution of the time-dependent Schr\"{o}dinger equation for a model system of two one-dimensional electrons as well as an adiabatic analytic model that allows for a closed-form solution.Comment: 6 pages and 3 figure

    Characteristics of Phenotypic and Genetic Properties of <i>Francisella tularensis</i> 15 NIIEG Vaccine Strain with an Extended Storage Period

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    Investigated have been cultural-morphological, biochemical and genetic properties of lyophilized cultures of F. tularensis 15 NIIEG vaccine strain, accumulated within 60-years term and deposited at the State Collection of Pathogenic Microorganisms of Scientific Center on Expertise of Medical Application Products. The studies undertaken have demonstrated that storing of the strains in such a form at low temperatures, does not prevent changes of their genetic and phenotypic properties to the full extent. It is established that F. tularensis 15 NIIEG strain lyophilized in 1953, 1966, 1969, 2003 and 2012 maintains its immunogenic properties when cultivated on nutrient media Ft-agar with or without addition of blood, based on dissociation rates (87-99 %) of SR-colonies. While F. tularensis 15 NIIEG strain 1990 contains specified amounts (not less than 80 %) of immunogenic colonies if cultivated on nutrient media with the addition of blood, and fails to meet the requirements - if cultivated without. Identified in F. tularensis 15 NIIEG strain 1987 SR-colony decrement of 70-75 % in case of cultivation with or without addition of blood testifies to the deterioration of its immunogenic properties. RAPD and ERIC typing has showed high stability of the genome of F. tularensis 15 NIIEG cultures lyophilized at different times. Tularemia microbe vaccine strain has unique RAPD and ERIC profiles, insignificant alteration of which is observed upon storage of pathogen subculture in the dried from

    Hadronic Regge Trajectories: Problems and Approaches

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    We scrutinized hadronic Regge trajectories in a framework of two different models --- string and potential. Our results are compared with broad spectrum of existing theoretical quark models and all experimental data from PDG98. It was recognized that Regge trajectories for mesons and baryons are not straight and parallel lines in general in the current resonance region both experimentally and theoretically, but very often have appreciable curvature, which is flavor-dependent. For a set of baryon Regge trajectories this fact is well described in the considered potential model. The standard string models predict linear trajectories at high angular momenta J with some form of nonlinearity at low J.Comment: 15 pages, 9 figures, LaTe

    STUDY OF MINIMAL RESIDUAL DISEASE BY MULTICOLOR FLOW CYTOMETRY IN MULTIPLE MYELOMA AFTER AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION

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    The frequency of achieving complete remission, as well as overall and disease-free survival, in multiple myeloma (MM) had increased due to introduction in MM treatment regimens of high-dose chemotherapy with following autologous hematopoietic stem cell transplantation (ASCT). However the number of relapses remains high, caused by persistence of residual tumor cells, i.e., the presence of minimal residual disease (MRD). One of the methods for MRD study is multicolor flow cytometry (MFC) where abnormal expression of surface antigens on myeloma plasma cells (PC) is determined. The aim of our study was to investigate the MRD by MFC before and after ASCT, the frequency of MRD-negative status achievement in complete remission (CR) patients at +100 days after ASCT and the frequency of abnormal expressed antigens on myeloma plasma cells. The study included40 MMpatients in CR at +100 days after ASCT and showed that the most common aberrations of PC were: abnormal absence of CD19 and/or CD27, decreased expression of CD38 and abnormal presence of CD56. The proportion of myeloma PCs from all bone marrow cells decreased significantly after ASCT: 20 % of patients acquired MRD-negative status, 10 % had a decrease in the number of abnormal PCs by one fold. Analysis of probability of immunochemical relapse showed that the worst prognosis was in patients with MRD-positive status before and after ASCT. During the MRD monitoring within 3-18 months, MRD-relapses were detected with the subsequent development of immunochemical relapse. The detection MRD in the dynamics is more informative than the study at only one step of therapy. It may help to select more adequate treatment for patient with multiple myeloma in each specific case

    Modeling the Subsurface Structure of Sunspots

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    While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

    Disinfection of Surfaces Contaminated with SARS-CoV-2 Coronavirus by UV Radiation of Low-Pressure Mercury-Vapour Lamp

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    The aim of the work was to determine the effective ultraviolet (UV) doses required for the disinfection of surfaces contaminated with the SARS-CoV-2 coronavirus using a low-pressure mercury lamp. Materials and methods. To carry out prompt disinfection of surfaces, a specially designed source of UV radiation with a power of 7.5 W at a wavelength of 254 nm in the form of a portable flashlight was employed, which has a high efficiency of UV radiation output and the possibility of long-term autonomous operation from a compact battery. In the studies, a suspension culture of the SARS-CoV-2 coronavirus with biological activity of 5.3∙106 PFU/ml was used. The objects of testing were plastic Petri dishes (disposable) and office paper (grade C, density 80 g/m2 ). Results and discussion. Doses of UV radiation that provide disinfection of surfaces contaminated with the COVID-19 pathogen with an efficiency of 99.0 % (paper) to 99.95 % (plastic) have been determined. The results obtained make it possible to recommend a portable UV irradiator for use in the practice of preventive measures to combat the spread of the disease caused by the SARS-CoV-2 coronavirus
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