140 research outputs found

    Method of combating fatigue destruction of steel structures of mine hoisting machines

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    The article presents the information of the identified defects of fatigue failure of steel structures of the brake mechanism of mine cable hoisting machines used to transport metallurgical coke from the mine to the surface. Using non-destructive testing methods a survey was carried out of the brake mechanisms of sixty mine cable hoisting machines. A method was developed to combat the fatigue failure of steel structures through the use of reinforcing elements to reduce their metal consumption and increase resistance to fatigue failure, while the use of expensive high-strength alloys is completely eliminated. To study the stress-strain state and fatigue failure of steel structures, a computer simulation method was used. Using the ANSYS computer program, the optimal forms of reinforcing elements were established and the loaded part of steel structures in continuous operation was simulated. Eleven computer models of a steel beam with various reinforcing elements were developed. The research results were used in practice in the repair of steel structures

    Influence of a dielectric medium on the phase state of carbon dioxide

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    The phase state of carbon dioxide gas dissolved in liquid n-heptane is determined by experimental investigations of the temperature dependences (180 < T < 250°K) of the spin-lattice relaxation time of protons, the coefficient of translational self-diffusion of n-heptane molecules and the nuclear magnetic resonance (NMR) linewidth of carbon13C. © 1987 Plenum Publishing Corporation

    The impact of the nonlinear effects on thermally stimulated depolarization currents in ion dielectrics

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    In this paper, the methods described the calculation of thermally stimulated depolarization currents in materials of the HBC class. In the identification of nonlinear processes of thermally stimulated depolarization, at this stage of the research, as defining criteria the authors consider the calculation of the dielectric initial polarization in the infinite approximation of perturbation theory (at the fundamental frequency fields) and calculation of kinetic coefficients in functions of the polarizing field intensity. Generalized nonlinear expressions for the complex dielectric constant and polarization are formulated, which are performed at the fundamental frequency of the alternating polarizing field. The generalized equations that are nonlinear by the field for kinetic coefficients of the kinetic equation are formulated. The obtained theoretical results are of current interest from the perspective of further development of analytical and computer methods of research and prediction of HBC properties as perspective nonlinear materials for a number of branches of modern industry

    Treatment of the amyotrophic lateral sclerosis using of genetically modified umbilical cord blood mononuclear cells in the preclinical studies

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    Development of the fundamental and clinical «regenerative medicine» is based on the progress of gene, stem cell and gene-cell biotechnologies. However, the reliable preclinical investigations on animal models and more over clinical trials stay far away from the available nowadays gene and cell constructions. Neuroscience is one of the fast growing fields of knowledge in biology and medicine. Pioneer experiments in neuroscience promises breakthrough in the innovative methods for treatment of neurodegenerative diseases in near future. This review addresses strategies for gene-cell therapy of neurodegenerative diseases by the example of amyotrophic lateral sclerosis. Precisely gene modification of mononuclear fraction of umbilical cord blood cells (UCBC) by dual cassette plasmid vectors is observed. Based on our own results of transplantation of genetically modified UCBC overexpressing recombinant neural cell adhesion molecule L1, vascular endothelial growth factor, fibroblast growth factor 2, and glial derived neurotrophic factor in different combinations we provide the experimental data for usefulness of transplantation of gene modified UCBC for treating neurodegenerative diseases. In the review we discuss the efficacy of gene modification of UCBC not only for secretion of recombinant proteins, but in increasing of transplanted cells survivability, their migration possibilities and capability to differentiate in endothelial, microglial and macroglial cell types

    New NIR-emissive tetranuclear Er(III) complexes with 4-hydroxo-2,1,3-benzothiadiazolate and dibenzoylmethanate ligands: synthesis and characterization

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    New tetranuclear heteroleptic complexes [Er4(dbm)6(O-btd)4(OH)2] (1) and [Er4(dbm)4(O-btd)6(OH)2] (2) (O-btd = 4-hydroxo-2,1,3-benzothiadiazolate and dbm = dibenzoylmethanide) and their solvates with toluene, THF and CH2Cl2 were prepared using two synthetic approaches. The structures of the products were confirmed by single-crystal X-ray diffraction. Magnetic properties of 1 and 2 are in good agreement with X-ray data. The effective magnetic moment (μeff) values at 300 K for 1 and 2 corresponds to a system of 4 non-interacting Er(III) ions in the ground state 4J15/2 with g = 6/5. At ambient temperature and upon excitation with λexc = 450 nm, complexes 1 and 2 exhibit luminescence at ∼1530 nm, i.e. in the near infra-red (NIR) region. The luminescence intensity grows with increasing the number of the (O-btd)−ligands in the complexes. This observation suggests (O-btd)− as a new efficient antenna ligand for the lanthanide-based NIR luminescence

    Human umbilical cord blood mononuclear cells transfected with dual cassette plasmids (VEGF + neurotrophic factor) for the treatment of amyotrophic lateral sclerosis

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    To increase the viability of neural cells in neurodegenerative diseases, after neurotraumas and ischemic strokes the most important neurotrophic and neuroprotective factors, which can be used as therapeutic agents were identified in long-term studies in vitro and in vivo. These include brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF), insulin-like growth factor (IGF) and vascular endothelial growth factor (VEGF). One of the promising ways of the delivery of supporting neuron survival factors is considered to be transplantation of genetically modified cells overexpressing recombinant therapeutic genes. This article describes generation of cellular delivery vectors of therapeutic genes - human umbilical cord blood mononuclear cells genetically modified by dual cassette plasmids, expressing two therapeutic genes. Efficiency of transgene expression was confirmed in vitro using RT-PCR. Analysis of survival, migration, and phenotype of genetically modified cells was performed 2 weeks after transplantation into transgenic mice with amyotrophic lateral sclerosis phenotype

    New NIR-emissive tetranuclear Er(III) complexes with 4-hydroxo-2,1,3-benzothiadiazolate and dibenzoylmethanide ligands: Synthesis and characterization

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    © The Royal Society of Chemistry 2015. New tetranuclear heteroleptic complexes [Er4(dbm)6(O-btd)4(OH)2] (1) and [Er4(dbm)4(O-btd)6(OH)2] (2) (O-btd = 4-hydroxo-2,1,3-benzothiadiazolate and dbm = dibenzoylmethanide) and their solvates with toluene, THF and CH2Cl2 were prepared using two synthetic approaches. The structures of the products were confirmed by single-crystal X-ray diffraction. Magnetic properties of 1 and 2 are in good agreement with X-ray data. The effective magnetic moment (μeff) values at 300 K for 1 and 2 corresponds to a system of 4 non-interacting Er(iii) ions in the ground state 4J15/2 with g = 6/5. At ambient temperature and upon excitation with λexc = 450 nm, complexes 1 and 2 exhibit luminescence at ∼1530 nm, i.e. in the near infra-red (NIR) region. The luminescence intensity grows with increasing the number of the (O-btd)- ligands in the complexes. This observation suggests (O-btd)- as a new efficient antenna ligand for the lanthanide-based NIR luminescence
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