22 research outputs found

    On the intersection of the classes of doubly diagonally dominant matrices and S-strictly diagonally dominant matrices

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    We denote by H0 the subclass of H-matrices consisting of all the matrices that lay simultaneously on the classes of doubly diagonally dominant (DDD) matrices (A = [aij ] ∈ Cn×n : |aii||ajj | ≥ k =i |aik| k =j |ajk|, i = j) and S-strictly diagonally dominant (S-SDD) matrices. Notice that strictly doubly diagonally dominant matrices (also called Ostrowsky matrices) are a subclass of H0. Strictly diagonally dominant matrices (SDD) are also a subclass of H0. In this paper we analyze some properties of the class H0 = DDD ∩ S-SDD

    The Impact of Hyperosmolality on Activation and Differentiation of B Lymphoid Cells

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    B lymphocytes, as a central part of adaptive immune responses, have the ability to fight against an almost unlimited numbers of pathogens. Impairment of B cell development, activation and differentiation to antibody secreting plasma cells can lead to malignancy, allergy, autoimmunity and immunodeficiency. However, the impact of environmental factors, such as hyperosmolality or osmotic stress caused by varying salt concentrations in different lymphoid organs, on these processes is not well-understood. Here, we report that B cells respond to osmotic stress in a biphasic manner. Initially, increased osmolality boosted B cell activation and differentiation as shown by an untimely downregulation of Pax5 as well as upregulation of CD138. However, in the second phase, we observed an increase in cell death and impaired plasmablast differentiation. Osmotic stress resulted in impaired class switch to IgG1, inhibition of phosphorylation of p38 mitogen-activated kinase and a delayed NFAT5 response. Overall, these findings demonstrate the importance of microenvironmental hyperosmolality and osmotic stress caused by NaCl for B cell activation and differentiation

    Benchmarking as a Tool for Effective Business Enterprises in Crisis Conditions

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    How to realize effective work in the time of the world economy crisis and how to keep ground, it is real challenge. It is possible to tell that crisis is moving us back in the period of financial break, in the time around years of the 30, to the passed century. How to watch of threats and take the opportunities? How to do the business in the successfully way? Trying to compare yourself with somebody who is better then you in the time of crisis, to do the Bench mark and use all good results, from successful corporations, it is maybe a possible answer to the problems in what we are: how to do the effective job

    Cavitation resistance of basalt-based protective coatings and epoxy system

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    The paper presents the results of synthesis and characterization of new refractory coatings based on basalt and epoxy system. Coatings are intended to protect the surfaces of parts of equipment and various structures in civil and mechanical engineering and metallurgy which are exposed to wear, corrosion, or cavitation during exploitation. Coating composition, procedures for preparation of components from coating composition, synthesis procedures, and application of coatings are investigated. Several methods are used to characterize the coating: X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), optical microscopy and ultrasonic vibration method with a stationary sample according to ASTM G32 standard. Material resistance to the action of cavitation is determined using the ultrasonic method. In order to monitor the formation and development of surface damage on samples under the effect of cavitation, the morphology of surface coating damage is analysed using scanning electron microscopy. Results show high resistance of the tested basalt-based coatings under the action of cavitation, with low cavitation rate (0.04 mg/min), low mass losses of coating and minor surface damage during exposure. This indicates the possibility of applying this type of refractory coating for the protection of various metallic and non-metallic structures in conditions of wear and cavitation

    The Impact of Hyperosmolality on Activation and Differentiation of B Lymphoid Cells

    Get PDF
    B lymphocytes, as a central part of adaptive immune responses, have the ability to fight against an almost unlimited numbers of pathogens. Impairment of B cell development, activation and differentiation to antibody secreting plasma cells can lead to malignancy, allergy, autoimmunity and immunodeficiency. However, the impact of environmental factors, such as hyperosmolality or osmotic stress caused by varying salt concentrations in different lymphoid organs, on these processes is not well-understood. Here, we report that B cells respond to osmotic stress in a biphasic manner. Initially, increased osmolality boosted B cell activation and differentiation as shown by an untimely downregulation of Pax5 as well as upregulation of CD138. However, in the second phase, we observed an increase in cell death and impaired plasmablast differentiation. Osmotic stress resulted in impaired class switch to IgG1, inhibition of phosphorylation of p38 mitogen-activated kinase and a delayed NFAT5 response. Overall, these findings demonstrate the importance of microenvironmental hyperosmolality and osmotic stress caused by NaCl for B cell activation and differentiation
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