2,056 research outputs found

    Pyrazinamide Effects on Cartilage Type II Collagen Amino Acid Composition

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    Introduction. Current therapeutic regimens with first-line antitubercular agents are associated to a high rate of adverse effects which could cause pronounced changes in collagen's contents and structure. Investigation of these changes is very important for optimization of antitubercular therapy and minimization of treatment-caused harm. The aim of present paper was to investigate potential effect of pyrazinamide on male rats' cartilage type II collagen amino acid composition. Materials and Methods. Wistar albino male rats (160–200 g b.w.) were divided into three groups: I—received pyrazinamide per os at a dose of 1000 mg/kg b.w./day; II—at a dose of 2000 mg/kg b.w./day, in both groups it was given for 60 days; III—control. After 60 days of the experiment, rats of the experimental (groups I and II) and control groups were sacrificed and the amino acids contents of male rat cartilage type II collagens were determined using amino acid analyzer. Results and Discussion. The study of pyrazinamide effects (administered in different doses) on rat cartilage type II collagen amino acid contents demonstrated presence of dose-dependent pyrazinamide-mediated quantitative and qualitative changes in these rat extracellular matrix proteins in comparison with control

    Study of Scintillator Strip with Wavelength Shifting Fiber and Silicon Photomultiplier

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    The performance of the 200×2.5×1200\times2.5\times1 cm3^3 plastic scintillator strip with wavelength shifting fiber read-out by two novel photodetectors called Silicon PhotoMultipliers (SiPMs) is discussed. The advantages of SiPM relative to the traditional multichannel photomultiplier are shown. Light yield and light attenuation measurements are presented. This technique can be used in muon or calorimeter systems.Comment: 9 pages, 5 figure

    Relativistic effects in proton-induced deuteron break-up at intermediate energies with forward emission of a fast proton pair

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    Recent data on the reaction pD -> (pp) n with a fast forward pp pair with very small excitation energy is analyzed within a covariant approach based on the Bethe-Salpeter formalism. It is demonstrated that the minimum non-relativistic amplitude is completely masked by relativistic effects, such as Lorentz boost and the negative-energy P components in the 1S_0 Bethe-Salpeter amplitude of the pp pair

    The relativistic impulse approximation for the exclusive electrodisintegration of the deuteron

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    The electrodisintegration of the deuteron in the frame of the Bethe-Salpeter approach with a separable kernel of the nucleon-nucleon interaction is considered. This conception keeps the covariance of a description of the process. A comparison of relativistic and nonrelativistic calculations is presented. The factorization of the cross section of the reaction in the impulse approximation is obtained by analytical calculations. It is shown that the photon-neutron interaction plays an important role.Comment: 31 pages, 14 figures, 1 tabl

    Scintillation counter with MRS APD light readout

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    START, a high-efficiency and low-noise scintillation detector for ionizing particles, was developed for the purpose of creating a high-granular system for triggering cosmic muons. Scintillation light in START is detected by MRS APDs (Avalanche Photo-Diodes with Metal-Resistance-Semiconductor structure), operated in the Geiger mode, which have 1 mm^2 sensitive areas. START is assembled from a 15 x 15 x 1 cm^3 scintillating plastic plate, two MRS APDs and two pieces of wavelength-shifting optical fiber stacked in circular coils inside the plastic. The front-end electronic card is mounted directly on the detector. Tests with START have confirmed its operational consistency, over 99% efficiency of MIP registration and good homogeneity. START demonstrates a low intrinsic noise of about 10^{-2} Hz. If these detectors are to be mass-produced, the cost of a mosaic array of STARTs is estimated at a moderate level of 2-3 kUSD/m^2.Comment: 6 pages, 5 figure

    Magnetoresistive study of antiferromagnetic--weak ferromagnetic transition in single-crystal La2_{2}CuO4+δ_{4+\delta}

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    The resistive measurements were made to study the magnetic field-induced antiferromagnetic (AF) - weak ferromagnetic (WF) transition in La2_2CuO4_4 single-crystal. The magnetic field (DC or pulsed) was applied normally to the CuO2_2 layers. The transition manifested itself in a drastic decrease of the resistance in critical fields of ~5-7 T. The study is the first to display the effect of the AF -WF transition on the conductivity of the La2_2CuO4_4 single-crystal in the parallel - to - CuO2_2 layers direction. The results provide support for the 3-dimensional nature of the hopping conduction of this layered oxide.Comment: 8 pages, 7 figures, RevTe

    Ekspresija CYP2E1 u testisima štakora i alkoholom prouzrokovane promjene indeksa spermatogeneze i kolagena tipa I

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    This study is a complex investigation of alcohol-mediated changes in CYP2E1 mRNA and protein expression in the testes, as well as spermatogenesis indices and type I collagen amino acid contents, in male rats. Wistar albino male rats were divided into two groups: I – control (intact animals), II – experimental (chronic alcoholism, exposure to a 15 % ethanol aqueous solution during 150 days). The destructive changes in the spermatogenic epithelium were accompanied by a decrease in sperm number and motility time. CYP2E1 mRNA and protein expression were elevated in the testes 3 and 1.4 times, respectively. Also, significantly lower contents of lysine, glutamic acid, serine, proline, alanine, valine, and phenylalanine residues accompanied by an increase of hydroxyproline, glycine, and threonine residue contents were detected in the skin type I collagen of the experimental group. Chronic ethanol consumption caused testicular failure along with an overexpression of CYP2E1 mRNA and protein in the testes as well as quantitative changes in type I collagen amino acid contents. The profound alcohol-mediated changes in collagen type I amino acid contents may have affected the spermatogenic epithelium state. The modulation of testicular cytochrome P450 2E1 mRNA and protein expression could change the functioning of this isozyme in target organs and take part in the mechanism of ethanol gonadotoxicity.Ovo istraživanje proučava alkoholom uzrokovane promjene u ekspresiji CYP2E1 mRNA i bjelančevina iz testisa, indeksu spermatogeneze i aminokiselinskom sastavu kolagena tipa I u muških štakora. Albino štakori tipa Wistar podijeljeni su u dvije skupine: I – kontrolna, II – eksperimentalna (kronični alkoholizam, izloženi 150 dana 15-postotnoj vodenoj otopini etanola). Destruktivne promjene u spermatogenetskom epitelu popraćene su smanjenjem broja i pokretljivosti spermija. Ekspresija mRNA gena CYP2E1 i bjelančevina bila je povišena u testisima 3, odnosno 1,4 puta. Također, u kolagenu tipa I ustanovljene su značajno manje količine lizina, glutaminske kiseline, serina, prolina, alanina, valina i fenilalanina, te veće količine ostataka hidroksiprolina, glicina i treonina. Kronična konzumacija etanola uzrokovala je otkazivanje testisa uz izraženu ekspresiju mRNA CYP2E1 i bjelančevina u testisima, te kvantitativne promjene u aminokiselinama kolagena tipa I. Izražene alkoholom prouzrokovane promjene mogle su utjecati na spermatogenetski epitel. Modulacija ekspresije mRNA testikularnog citokroma P450-2E1 i bjelančevina mogla bi promijeniti djelovanje ovoga izozima u ciljnim organima te sudjelovati u mehanizmu gonadotoksičnosti etanola

    Verificação do apoio gerencial da trajetória profissional e educacional dos alunos no ambiente educacional sociocultural da universidade

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    The relevance of the study is determined by the processes of modernization of vocational education and the transition to the educational standards of the third generation, which open up new opportunities for students and teachers. Step-by-step management support of professional and educational trajectory of students requires organizational conditions and the development of technology for its practical implementation. Identifying the level of motivation in students when choosing a future profession allows assessing the level of inclusion of students in educational and cognitive activities and determining how far it is from the optimal motivational level, which allows the student achieving their goals, advancing in professional and personal development. At the initial stage of diagnosis, the analysis of professional experience of students, successes and problems in the training practice of the first year of training is carried out, at the next stage, the results of research activities on the results of the second year of training are analyzed. Activity-practical criterion, indicators of which are formed professional skills, primary professional experience, being in a sense the total overall performance indicator of professional and personal development of students, also changes qualitatively in the direction of improvement.La relevancia del estudio está determinada por los procesos de modernización de la educación vocacional y la transición a los estándares educativos de la tercera generación, que abren nuevas oportunidades para estudiantes y profesores. El apoyo paso a paso de la gestión de la trayectoria profesional y educativa de los estudiantes requiere condiciones organizativas y el desarrollo de tecnología para su implementación práctica. Identificar el nivel de motivación en los estudiantes al elegir una profesión futura permite evaluar el nivel de inclusión de los estudiantes en actividades educativas y cognitivas y determinar qué tan lejos está del nivel motivacional óptimo, lo que permite al estudiante alcanzar sus metas, avanzando en lo profesional y en el desarrollo peronal. En la etapa inicial del diagnóstico, el análisis de la experiencia profesional de los estudiantes, los éxitos y los problemas en la práctica de capacitación del primer año se lleva a cabo. En la siguiente etapa, se analizan los resultados de las actividades de investigación sobre los resultados del segundo año de capacitación. El criterio práctico de la actividad, cuyos indicadores son habilidades profesionales formadas, experiencia profesional primaria, siendo en cierto sentido el indicador de rendimiento global total del desarrollo profesional y personal de los estudiantes, también cambia cualitativamente en la dirección de la mejora.A relevância do estudo é determinada pelos processos de modernização do ensino profissional e pela transição para os padrões educacionais da terceira geração, que abrem novas oportunidades para alunos e professores. O apoio passo a passo da gestão da trajetória profissional e educacional dos alunos requer condições organizacionais e o desenvolvimento de tecnologia para sua implementação prática. Identificar o nível de motivação dos alunos na escolha de uma profissão futura para avaliar o nível de inclusão de alunos em actividades educativas e cognitivas e determinar o quão longe é o nível motivacional ideal, que permite que o aluno a alcançar seus objetivos, o progresso na profissional e no desenvolvimento peronal. Na fase inicial do diagnóstico, ocorre a análise da experiência profissional dos alunos, sucessos e problemas na prática do primeiro ano de treinamento. Na etapa seguinte, são analisados os resultados das atividades de pesquisa sobre os resultados do segundo ano de treinamento. O critério prático da atividade, cujos indicadores são habilidades profissionais treinadas, experiência profissional primária, sendo de certa forma o indicador do desempenho global total do desenvolvimento profissional e pessoal dos estudantes, também muda qualitativamente na direção da melhoria
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