120 research outputs found

    Tuning of tunneling current noise spectra singularities by localized states charging

    Full text link
    We report the results of theoretical investigations of tunneling current noise spectra in a wide range of applied bias voltage. Localized states of individual impurity atoms play an important role in tunneling current noise formation. It was found that switching "on" and "off" of Coulomb interaction of conduction electrons with two charged localized states results in power law singularity of low-frequency tunneling current noise spectrum (1/fα1/f^{\alpha}) and also results on high frequency component of tunneling current spectra (singular peaks appear).Comment: 7 pages, 4 figure

    Atrial Fibrillation Triggers in Patients with Coronary Artery Disease and Subclinical Thyrotoxicosis

    Get PDF
    We examined 202 patients with paroxysms of symptomatic and asymptomatic atrial fibrillation (AF), some of whom suffered from coronary artery disease (CAD) andsubclinical thyrotoxicosis (ST). Healthy individuals acted as a comparison group. It was revealed that in all studied groups, extrasystoles and paroxysms of reciprocal atrioventricular orthodortic and nodal tachycardia was the role of the triggering factors of AF. In patients with ST without CAD and in healthy persons, the paroxysms of tachycardia are short and unstable. When CAD combined with ST, the number of extrasystoles and AF paroxysms is significantly higher than only in ST and in healthy individuals. It was found that in patients with asymptomatic AF the total number of extrasystoles and paroxysms of tachycardia is greater than in the case of symptomatic. Thus, the identification of concomitant subclinical thyrotoxicosis in a patient with CAD should alert the clinician to the development and progression of atrial fibrillation. It should be given great attention to screening thyroid pathology in patients with CAD. Keywords: atrial fibrillation, coronary artery disease, subclinical thyrotoxicosis

    Analysis of Implementation of the Requirements for Provision of Biological Safety at a Potentially Hazardous Facility

    Get PDF
    Discussed are the problems of implementation of requirements for the provision of biological safety at a potentially hazardous biological facility by the example of Federal Budgetary Institution of Science “State Scientific Center of Applied Microbiology and Biotechnology” of the Rospotrebnadzor. Identified are the necessary and sufficient organizational-andpreventive and control measures and procedures on management of works with microorganisms of the I-IV groups of pathogenicity (hazard) in isolated labs of the Center. Issues associated with exploitation of biological safety engineering systems and assessment of their protective efficiency, problems of medical support of the activities and response to the emergency situations of biological character with the involvement of doctors from a specialized medical wing of the Federal Medical-Biological Agency of the Russian Federation, serving the facility on a constant basis, are analyzed. Determined have been approaches to and principles of establishing the requirements for the system of biological safety at a potentially hazardous biological facility taking into account all the range of biological risks when working with microorganisms. Complex approach and realization of appropriate necessary measures in the sphere of biological safety provision, creating an environment for the reduction of biological risks up to acceptable level while working with pathogenic microorganisms, can be an effective solution of the problem on the whole

    On the phenomenology of a Z' coupling only to third-family fermions

    Get PDF
    The phenomenology of an additional U(1) neutral gauge boson Z' coupled to the third family of fermions is discussed. One might expect such a particle to contribute to processes where taus, b and t quarks are produced. Precision data from LEP1 put severe constraints on the mixing and heavy-boson mass. We find that the effects of such a particle could not be observed at hadronic colliders, be it at the Tevatron or the LHC, because of the QCD background. At LEP2 and future e^+e^- linear colliders, one could instead hope to observe such effects, in particular for b\bar b final states.Comment: 36 pages, LaTeX, including 12 figure

    Peculiarities of the Conjugative pSa Plasmid Transfer from <I>Escherichia coli</I> into <I>Francisella tularensis</I>

    Get PDF
    per a recipient cell). pSa′ plasmid molds several topological shapes with variable electrophoretic mobility in E. coli C600, while in tularemia microbe, this plasmid has only one shape. After the transfer of the plasmid from E. coli cells into F. tularensis cells each individual clone of tularemia microbe possesses a plasmid which differs in its electrophoretic mobility from plasmids of other clones

    Optimization of the Process of Cholera Chemical Pelleted Vaccine Production Using Ultrafiltration Technology

    Get PDF
    Technology of O-antigen obtaining from Vibrio cholerae M41production strain, using the hollow fiber ultrafiltration modules, is developed and introduced into cholera vaccine manufacturing. Application of ultrafiltration makes it possible to obtain native high-activity O-antigen preparations which comply with the current regulatory requirements. Besides, it provides for economy (10-15-fold) of ammonium sulphate, used for antigen precipitation, reduces the duration of technological cycle (2 times), and the labor inputs. The technology of protective antigen concentrating is tested on V. cholerae strains MO45 and KM137 of O139 serogroup. Three series of experimental V. cholerae O139 vaccine are obtained

    Development and Testing of Monoclonal Antibodies-Based Diagnostic Preparation for <i>Bacillus anthracis</i> Spores Detection Using Latex Agglutination Method

    Get PDF
    Immobilization of anti-B. anthracis monoclonal antibodies (MAbs) on latex microparticles was studied, the optimal load of these MAbs was determined to be 20 µg for 50 µl of the stock latex suspension. The highest sensitivity of latex agglutination test was observed for 1E6 MAbs. Latex suspensions with immobilized MAbs were lyophilized. Their sensitivity and specificity were shown to be highly competitive with those of the stock liquid latex suspension. Latex diagnosticum for Bacillus anthracis spores detection was constructed on the basis of these lyophilized reagents, developed and approved was the regulatory documentation that included their application instructions and technical specifications. Carried out were inter-laboratory and commission tests of experimental prototypes of the designed latex diagnosticum. These preparations demonstrated high sensitivity (from 1·105 to 2·106 spores/ml and even more) and specificity (absence of cross-reactions with spores of different species of sporogenous bacilli at concentration of 108 spores/ml)

    B-lymphocyte aggregation in the lung tissue is a pathogenic factor in experimental infection caused by Mycobacterium avium

    Get PDF
    When infecting the lungs with Mycobacterium avium of B6 line mice genetically susceptible to this infection the compact aggregates (follicles) of B-lymphocytes are formed with the peak at the 11-13th week after the infection. Physiological role of these cellular accumulations remained unclear. Having applied segregative genetic analysis to allele conglutination of Slc11a1 gene with two signs – quantity of mycobacteria and accumulation of B-cellular follicles to the F2 mice from crossing (В6 × I/St), one managed to find out that the quantity and size of follicles directly correlate with M. avium replication in the lungs. Thus this type of the lung tissue infiltration does not protect the host from infection and it is a pathogenic factor

    Immunobiological Properties of <i>Francisella tularensis</i> 15/10 Strain with Deleted recA Gene

    Get PDF
    Deletion of recA gene in Francisella tularensis 15/10 genome leads to the increase in its sensitivity to ultraviolet irradiation, reduction of the homologous recombination capacity, and a slight decline of virulence for mice. Efficacy of Francisella tularensis 15/10ΔrecA reproduction within microphage-like cells, its resistance to normal rabbit serum, and protective properties on the mouse model of tularemia are the same as in original Francisella tularensis 15/10
    corecore