100 research outputs found

    SYNTHESIS PROGRAM OF HARMONIC RACK-AND-PINION DRIVE CAM GEAR

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    Data on granulometric composition of calcium phosphate obtained by dispersion method

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    The kinetics of calcium phosphate crystallization from model solutions of saliva and liquid phase of dental plaque has been studied by the dispersion method. It was found that the composition of the saliva model system is favorable for the growth of larger crystals. The size of the particles in crystallization varies nonlinearly. As supersaturation grows, the amount of formed particles increases, however, the average rate of crystallite growth decreases

    Study of thermal effects of silicate-containing hydroxyapatites

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    The possibility of modifications of hydroxyapatite silicate ions, from the extracellular fluid prototype solution under near-physiological conditions has been studied. Formation of silicon-structured hydroxyapatite with different extent of substitution of phosphate groups in the silicate group has been established through chemical and X-ray diffraction analyses, FTIR spectroscopy and optical microscopy. The results obtained are in agreement and suggest the possibility of substitution of phosphate groups for silicate groups in the hydroxyapatite structure when introducing different sources of silica, tetraethoxysilane and sodium silicate, in the reaction mixture. Growth in the amount of silicon in Si-HA results in the increase in the thermal stability of the samples. The greatest mass loss occurs at temperatures in the range of 25-400 °С that is caused by the removal of the crystallization and adsorption water and volatile impurities. It is shown that the modified apatites are of imperfect structure and crystallize in a nanocrystalline state

    Physics and chemistry of producing silicon-hydroxylapatite-titanium composite materials

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    In the research, Si-HA poweders have been synthesized using SBF solution with different content of silicon. It was found that all the samples synthesized from the model solution of extracellular fluid under varying concentration of silicate ions are single-phase and repesent hydroxyapatite. The nature of the reagent containing SiO[44]- ions does not affect the hydroxyapatite structure. In the study of the surface and morphological characteristics of the phosphate coatings modified by silicon ions, it was found that as the degree of phosphate calcium substitution by SiO[44]- ions increases, the surface wettability on the titanium substrates deteriorates and cohesive energy decreases. It is shown that the titanium coating is formed in three stages. After irradiation of titanium substrates coated with Si-HA, the crystals can keep growing and the surface can keep regenerating

    Administrative Liability for Violations of Quarantine Restrictions

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    The article analyzes the administrative responsibility provided for violation of the quarantine restrictions in the light of practical experience in the implementation of quarantine measures in the territory of Omsk region in the period of emergency, imposed upon discovery in the region of dangerous viral diseases of animals - African swine fever. The Authors propose to expand the powers of police officers to draw up protocols on administrative offenses under articles 10.6, 10.7, 10.8 of the Code of the Russian Federation on Administrative Offences, also substantiates the need to tighten administrative responsibility for disobeying a legal order or request of a police officer in connection with the performance of his duties during the emergency

    Homologs of the rolC gene of naturally transgenic toadflaxes Linaria vulgaris and Linaria creticola are expressed in vitro

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    Agrobacterium mediated transformation is the most common way for obtaining transgenic plants in laboratory conditions. At the same time, there are species inside the genera Nicotiana, Linaria and Ipomoea that contain homologs of agrobacterial T-DNA genes as a result of genetic transformation of their ancestral forms in natural conditions. Such plants are called naturally transgenic plants, and T-DNA in their genomes is called cellular (cT-DNA). It is proposed that in the evolution of these genera, the introduced sequences played an important role. This idea is confirmed by the data on the expression of some T-DNA genes in Nicotiana and Ipomoea. Until the last moment, the expression of cT-DNA genes in Linaria has not been documented. However, the analysis of the nucleotide sequence indicates the functionality of rolC gene in L. vulgaris Mill., L. acutiloba Fisch. ex Rchb., L. genistifolia (L.) Mill. In this research work, we have sequenced the rolC homolog in one more toadflax species (Linaria creticola Kuprian). The in silico analysis of this gene has shown that it can encode a full-length peptide. Using the real time RT-PCR method, we have demonstrated that the rolC homolog is expressed in vitro in shoots, roots and calli of L. vulgaris Mill., as well as in shoots of L. creticola Kuprian. The results obtained are an important argument in favor of the fact that cT-DNA is functional and that its fixation in genomes played a certain role in the evolutionary process. However, the level of expression of the gene studied is quite low. A similar trend was observed in other naturally transgenic species. This can explain the absence of explicit morphological differences of species containing cT-DNA from their non-transgenic relatives

    Awareness of students about narcotic dependence in Poltava

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    Cтудентська молодь відповідала на різні питання, які були представлені в анкеті, щодо обізнаності їх шкідливості вживання наркотичних препаратів. Була виявлена частку тих, хто хоча б раз пробував наркотичні препарати або вживає їх регулярно

    Thermal effects of carbonated hydroxyapatite modified by glycine and albumin

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    In this work calcium phosphate powders were obtained by precipitation method from simulated solutions of synovial fluid containing glycine and albumin. X-ray diffraction and IR spectroscopy determined that all samples are single-phase and are presented by carbonate containing hydroxyapatite (CHA). The thermograms of solid phases of CHA were obtained and analyzed; five stages of transformation in the temperature range of 25-1000°C were marked. It is shown that in this temperature range dehydration, decarboxylation and thermal degradation of amino acid and protein connected to the surface of solid phase occur. The tendency of temperature lowering of the decomposition of powders synthesized from a medium containing organic substances was determined. Results demonstrate a direct dependence between the concentration of the amino acid in a model solution and its content in the solid phase

    U-Pb LA-ICP-MS DATING OF DETRITAL ZIRCON FROM UPPER PERMIAN SANDSTONE OF THE BOYEVAYA GORA SECTION (ORENBURG REGION, SOUTHERN CIS-URALS)

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    The first results of U-Pb LA-ICP-MS dating of 150 detrital zircon grains from the Upper Permian sandstone of the Boyevaya Gora section (Orenburg region, the Southern Cis-Urals) are presented. 95 conditional zircon U-Pb isotopic dates form two age peaks – 381 and 529 Ma. It is assumed that clastic material entered the sedimentation basin mainly due to erosion of the Early Hercynian Ural complexes and relics of the Protouralian-Timanian orogen

    Morphotypes and genetic diversity of <i>Dendrobaena schmidti</i> (Lumbricidae, Annelida)

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    Dendrobaena schmidti (Michaelsen, 1907) is a polymorphic earthworm species from the Caucasus and adjacent regions. Adult D. schmidti individuals have highly variable body size (from 1.5 to well over 10 cm) and color (from dark purple to total lack of pigmentation), so a lot of subspecies of D. schmidti have been described; however, the existence of most of them is currently under dispute. We studied the genetic diversity of D. schmidti from seven locations from the Western Caucasus using mitochondrial (a fragment of the cytochrome oxidase I gene) and nuclear (internal ribosomal transcribed spacer 2) DNA. For both genes studied, we found that our sample was split into two groups. The first group included somewhat bigger (3-7.5 cm) individuals that were only slightly pigmented or totally unpigmented (when fixed by ethanol). The second group contained small (1.7-3.5 cm) specimens with dark purple pigmentation. In one of the studied locations these two groups were found in sympatry. However, there were no absolute differences either in general appearance (pigmented/unpigmented, small/big) or among diagnostic characters. Although the two groups differed in size (the majority of individuals from the first group were 5-6 cm long, and of the second one, 2-3 cm), the studied samples overlapped to a certain degree. Pigmentation, despite apparent differences, was also unreliable, since it was heavily affected by fixation of the specimens. Thus, based on the obtained data we can conclude that D. schmidti consists of at least two species that have identical states of diagnostic characters, but differ in general appearance
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