395 research outputs found

    Investigation of the structure and microhardness of Mo-Fe-C coatings obtained by the electron beam injected in the atmosphere

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    In this work 'Mo-Fe-C' coatings fabricated on medium carbon steel by non-vacuum electron beam cladding were investigated. The structure of coatings and transition zones were studied by scanning electron microscopy (SEM). It was shown that an increase of Fe percentage in the cladding mixture led to a decrease of the eutectic volume fraction in the coating and was accompanied by the formation of the gradient structure between the coating and a substrate material. Measurements of microhardness in the cross section of samples revealed that the cladding of a 'Mo-C powder mixture contributed to a 4.5-fold increase of microhardness

    First Measurement of Proton-Proton Elastic Scattering at RHIC

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    The first result of the pp2pp experiment at RHIC on elastic scattering of polarized protons at sqrt{s} = 200 GeV is reported here. The exponential slope parameter b of the diffractive peak of the elastic cross section in the t range 0.010 <= |t| <= 0.019 (GeV/c)^2 was measured to be b = 16.3 +- 1.6 (stat.) +- 0.9 (syst.) (GeV/c)^{-2} .Comment: 9 pages 5 figure

    First Measurement of A_N at sqrt(s)=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

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    We report on the first measurement of the single spin analyzing power (A_N) at sqrt(s)=200GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). Data points were measured in the four momentum transfer t range 0.01 < |t| < 0.03 (GeV/c)^2. Our result, averaged over the whole t-interval is about one standard deviation above the calculation, which uses interference between electromagnetic spin-flip amplitude and hadronic non-flip amplitude, the source of A_N. The difference could be explained by an additional contribution of a hadronic spin-flip amplitude to A_N.Comment: 13 pages, 5 figures. New values of polarization errors. Final version submitted to Phys. Lett.

    Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

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    We present the first measurements of the double spin asymmetries A_NN and A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t as well as on the difference Delta(sigma_T) between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.

    Investigation of the structure and microhardness of Mo-Fe-C coatings obtained by the electron beam injected in the atmosphere

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    In this work 'Mo-Fe-C' coatings fabricated on medium carbon steel by non-vacuum electron beam cladding were investigated. The structure of coatings and transition zones were studied by scanning electron microscopy (SEM). It was shown that an increase of Fe percentage in the cladding mixture led to a decrease of the eutectic volume fraction in the coating and was accompanied by the formation of the gradient structure between the coating and a substrate material. Measurements of microhardness in the cross section of samples revealed that the cladding of a 'Mo-C powder mixture contributed to a 4.5-fold increase of microhardness

    Оценка уровня сывороточного BDNF при комплексной реабилитации пациентов с ишемическим инсультом с использованием традиционных подходов к восстановлению моторных функций

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    Aim. To assess the relationship between changes in serum brain-derived neurotrophic factor (BDNF) level, regression of motor deficiency, and restoration of functional activity in patients with ischemic stroke after stage II of medical rehabilitation.Materials and methods. The study included 49 patients with ischemic stroke in the middle cerebral artery after stage I of medical rehabilitation. Group I (n = 32) went through stage II of rehabilitation in the early recovery period, group II (n = 17) was discharged for outpatient monitoring at the place of residence. Observation points: day 14 and day 90. Evaluation scales: National Institute of Health Stroke Scale (NIHSS), Fugle – Meyer Scale (FMA), Modified Rankin Scale (mRS). Serum BDNF levels were determined using a MAGPIX multiplex analyzer (Luminex, USA).Results. A comparative analysis of the studied population showed that patients who underwent motor rehabilitation in the early recovery period had greater regression of neurologic deficit according to the ΔNIHSS scale (pgr.I–II = 0.043), a more pronounced increase in the functional activity on the ΔmRS scale (pgr.I–II = 0.047), and positive dynamics according to the FMA scale (pday14–90 = 0.003) in comparison with patients who received outpatient follow-up. The concentration of BDNF was significantly reduced by the end of the early recovery in the group II (pday14–90_gr.II = 0.002). On the contrary, there was no decrease in the level of the BDNF (pday14–90_gr.I = 0.613) in the group of patients undergoing rehabilitation.Conclusion. The results of the study demonstrated the clinical effectiveness of stage II of the comprehensive rehabilitation of patients in the early period of stroke recovery. We can suggest that the success of neurorehabilitation is closely associated with an increase of the BDNF level against the background of its performance. This makes BDNF a potential marker of evaluating the effectiveness of ongoing rehabilitation treatment.Цель – оценить взаимосвязь между изменением уровня сывороточного BDNF, регрессом моторного дефицита и восстановлением функциональной активности у пациентов с ишемическим инсультом после II этапа медицинской реабилитации.Материалы и методы. В исследовании приняли участие 49 пациентов с ишемическим инсультом в бассейне средней мозговой артерии после I этапа медицинской реабилитации. Группа I (n = 32) прошла II этап реабилитации в ранний восстановительный период, группа II (n = 17) выписана на амбулаторное наблюдение по месту жительства. Точки наблюдения: 14-е и 90-е сут. Оценочные шкалы: шкала инсульта Национального института здоровья (NIHSS), шкала Фугл – Мейера (FMA), модифицированная шкала Рэнкина (mRS). Уровень BDNF в сыворотке крови определяли на мультиплексном анализаторе MAGPIX (Luminex, США).Результаты. Сравнительный анализ исследуемой популяции показал, что пациенты, получавшие моторную реабилитацию в раннем восстановительном периоде, имеют бóльший регресс неврологического дефицита по шкале ΔNIHSS (pгр.I–II = 0,043), более выраженное повышение функциональной активности по шкале ΔmRS (pгрI.–II= 0,047) и положительную динамику по шкале FMA (pсут14–90= 0,003) в сравнении с пациентами, находившимися на амбулаторном наблюдении. Концентрация BDNF значимо снижалась к концу раннего восстановительного периода у пациентов на амбулаторном наблюдении в группе II (pсут14–90_гр.II = 0,002). В группе пациентов, проходивших реабилитацию, напротив, снижения уровня фактора не наблюдалось (pсут14–90_гр.I = 0,613).Заключение. Результаты исследования демонстрируют клиническую эффективность II этапа комплексной реабилитации пациентов в ранний восстановительный период инсульта и дают основание предположить, что успех нейрореабилитации тесно связан с повышением BDNF на фоне ее проведения. Это делает мозговой нейротрофический фактор потенциальным маркером оценки эффективности проводимого восстановительного лечения
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