DEVELOPMENT OF A MODEL FOR THE PRODUCTION OF METAL-POWDER COMPOSITIONS BASED ON CO-CR ALLOYS BY ELECTROEROSIVE DISPERSION

Abstract. The main requirement for powders for additive 3d technologies is the spherical shape of theparticles. Such particles are most compactly packed into a certain volume and ensure the "fluidity" of the powder composition in the supply systems of the material with minimal resistance. The wide use of the EED method for processing metal waste into powders for the purpose of their reuse and application in additive technologies is hampered by the lack in the scientific and technical literature of full-fledged information on the effect of the initial composition, regimes and media on the properties of powders and technologies of practical application. Therefore, in order to develop technologies for the reuse of electroerosive powders and to evaluate the effectiveness of their use, complex theoretical and experimental studies are required. The aim of the work was to develop a model for the production of metal powder compositions on the basis of Co-Cr alloys by electroerosive dispersion. Based on the results of the conducted studies, it has been established that the optimum parameters for the process of obtaining powder materials by the method of electroerosive dispersion of butyl alcohol are: capacitance of discharge capacitors 48 μF, voltage on electrodes 100 V, repetition rate of pulses 120 Hz

Modeling of temperature fields in the working chamber of the process furnace for REE synthesis

The results of mathematical modeling of temperature fields in the working chamber of the process furnace for special purposes are shown. Studied laboratory furnace is test equipment, which is used for practicing the stages of the technological process of continuous solid-phase synthesis of nanopowders of various purpose, such as obtaining of luminophore powders with rare earth elements oxides in its composition. Mathematical model adequacy is tested empirically

Melatonin in the dermal film limits the blood lymphocyte death in experimental thermal trauma

According to WHO data, about 11 million people need medical care after burns every year. In the overall structure of burns, the share of thermal trauma (TT) is 80%. Lymphocytopenia in TT is a risk factor for infectious complications and limited repair, and the development of new tools for TT therapy using dermal films is demanded in combustiology. The aim of the study was to evaluate changes in blood lymphocyte parameters, i.e., quantitative composition and their death during experimental thermal damage under the influence of the originally developed dermal film with melatonin (MT) in 49 inbred rats. The grade IIIA TT of 3.5% body surface was modeled by contact with boiling water for 12 s. Dermal films based on sodium carboxymethylcellulose supplemented with MT at a concentration of 0.005 g/g were applied daily for 5 days. The total numbers of lymphocytes, CD45RA+ and CD3+ cells, counts of lymphocytes with signs of partial necrosis, early and late apoptosis were assessed in blood. Relative decrease in the area and rate of the burn wound epithelization were also calculated. In animals with TT, the number of blood lymphocytes decreased on days 5, 10 and 20, including CD45RA+ and CD3+, along with increased amounts of lymphocytes with signs of necrosis, late and early apoptosis. By the term of 20 days, the burn wound area was reduced by 11.5%. Usage of dermal films with MT increased the amount of CD3+ cells in blood on days 5 and 10, CD45RA+ on days 5, 10 and 20, being associated with decreased number of lymphocytes showing signs of early apoptosis on days 5, 10 and 20, as well as features of necrosis and late apoptosis on days 5 following TT, accelerates the healing of a burn wound on days 5, 10 and 20 after TT. with a 20 cent reduction of its area by the day 20. Epithelization rate of the burn wound when applying MT-supplemented dermal film on days 5, 10 and 20 increases, along with higher amounts of CD3+ in the blood, and reduced counts of lymphocytes with signs of early apoptosis

Aromatic Amino Acids: Phenylalanine and Tyrosine in Patients with Hypertension and Coronary Artery Disease

Aim. To evaluate changes in the profile of aromatic amino acids (AAA) in patients with cardiovascular diseases (CVD): hypertension and coronary artery disease (CАD) in comparison with healthy study participants.Material and methods. One hundred and thirty-one participants were included in the study: 58 participants were included in the hypertension group, 46 in the CАD group, and 27 participants without signs of CVD in the control group. We used ultrahigh-performance liquid chromatography in combination with a triple quadrupole analyzer to measure plasma AAA: phenylalanine and tyrosine (Phe, Tyr) in all study participants. The association of AAA with biochemical blood test parameters, echocardiography (EchoCG) parameters, blood pressure level and clinical characteristics was analyzed.Results. A statistically significant difference in the level of concentration of Phe and Tyr was revealed (p=0,002 and p=0,024, respectively), comparing the three groups. Post-hoc analysis showed differences in the circulating level of both amino acids in patients with CAD vs the control group (Phe p=0,008 and Tyr p=0,020). Also a statistically significant difference in the level of Phe of the hypertension and CАD groups (p=0,017) was found. A negative correlation of low-density lipoproteins (LDL) with the level of Phe (r=-0,685, p<0,05) and Tyr (r=-0,583, p<0,05), as well as the level of Phe with total cholesterol (r=-0,461, p<0,05) was found in the group without CVD. In the hypertension group, only a weak positive correlation was found between very low-density lipoproteins and AAA levels (Phe r=0,326 and Tyr r=0,365, p<0,05), while in patients with CAD, the level of Phe and Tyr was negative correlated with high-density lipoprotein (r=-0,378 and r=-0,543, respectively, p<0,05), and the level of Tyr with LDL (r=0,349, p<0,05). When isolating the group with proven atherosclerosis of peripheral and/or coronary arteries, a statistically significant difference was revealed between the group of patients with CVD and clinical and instrumental signs of atherosclerosis and the group of patients with CVD without proven atherosclerosis in Phe level (p=0,019).Conclusion. Concentrations of AAA were higher in patients with CVD, comparing with the control group. At the same time, an increase of the Phe level was associated with the presence of peripheral or coronary atherosclerosis. The revealed correlations of AAA with EchoCG parameters and lipid spectrum parameters require further study to understand the involvement of AAA in pathogenesis of CVD and its potential role as treatment target

Возможности магнитно-резонансной визуализации в дифференциальной диагностике диабетической остеоартропатии и остеомиелита

Introduction. The problem of differential diagnostics of diabetic osteoarthropathy (DOAP) and osteomyelitis (OM) of the foot bones for patients with diabetes mellitus is still not finally solved, even with the use of MR imaging.The aim of the study. To find the MR signs that most accurately indicate the development of osteomyelitis (OM) of the foot bones in patients with diabetic osteoarthropathy (DOAP).Materials and methods. The study included 62 patientswho successfully completed treatment of uncomplicated or complicated DOAP and had the whole set of diagnostic criteria. They were divided into three groups: acute form of DOAP (n=31), DOAP+soft tissue infection (STI) (n=11) and DOAP+OM (n=20). There were identified6 MR-signs, which could become significant independent classifiers for the differential diagnostics of complicated and uncomplicated forms of DOAP. The diagnostic significance of MR symptoms was assessed in several steps with the use of various methods of statistical analysis.Results. There was revealed that the groups differ among themselves by 4 MR signs: characteristics of bone marrow edema (p=0.003); swelling of the supporting surfaces (p=0.006); restriction of diffusion in the bone marrow (p=0.001); fistulous course (p=0.001). Points were assigned to these MR criteria. According to the total MR score, groups 1 and 3 (p<0.001); 2 and 3 (p=0.001) differed among themselves. With the use of logistic regression and ROC analysis, we determined the significance of the total MR score for the diagnostics of osteomyelitis. Conclusion. The use of the MR-score summation system helped in the diagnosis of OM. The sum of MR scores ≥3 in the developed scoring system allowsto diagnose OM with high sensitivity (94.1%) and specificity (83.3%). >˂0.001); 2 and 3 (p=0.001) differed among themselves. With the use of logistic regression and ROC analysis, we determined the significance of the total MR score for the diagnostics of osteomyelitis.Conclusion. The use of the MR-score summation system helped in the diagnosis of OM. The sum of MR scores ≥3 in the developed scoring system allowsto diagnose OM with high sensitivity (94.1%) and specificity (83.3%).Введение. Проблема дифференциальной диагностики диабетической остеоартропатии (ДОАП) и остеомиелита (ОМ) костей стопы при сахарном диабете до сих пор окончательно не решена даже при использовании магнитно-резонансной (МР) визуализации.Цель работы: определение МР-признаков, наиболее точно указывающих на  развитие ОМ костей стопы у  пациентов с ДОАП.Материалы и методы. В исследование включено 62 пациента, имевших весь набор диагностических критериев, и успешно закончивших лечение по поводу неосложненной и осложненной ДОАП. Выделены три группы: острая форма ДОАП (n=31), ДОАП+инфекция мягких тканей (ИМТ) (n=11) и ДОАП+ОМ (n=20). Определено 6 МР-признаков, которые могли являться значимыми независимыми классификаторами в  дифференциальной диагностике осложненных и  неосложненных форм ДОАП. Оценку диагностической значимости МР-симптомов выполняли в несколько этапов, применяя различные методы статистического анализа.Результаты. Выявлено, что группы различаются между собой по 4 МР-признакам: характеристика отека костного мозга (р=0,003); отек опорных поверхностей (р=0,006); ограничение диффузии в  костном мозге (р=0,001); свищевой ход (р=0,001). Этим МР-критериям присвоены баллы. По суммарному МР-баллу различались между собой группы 1 и  3 (p<0,001); 2 и  3 (р=0,001). Используя логистическую регрессию и  ROCанализ, определили значимость суммарного МРбалла в диагностике остеомиелита. Заключение. Применение системы суммирования МР-баллов помогает в диагностике ОМ. Сумма МР-баллов ≥3 в разработанной балльной системе позволяет диагностировать ОМ с высокой чувствительностью (94,1%) и специфичностью (83,3%). Ключевые слова: диабетическая остеоартропатия, остеомиелит костей стопы, МРТ-диагностика>˂ 0,001); 2 и  3 (р=0,001). Используя логистическую регрессию и  ROCанализ, определили значимость суммарного МРбалла в диагностике остеомиелита.Заключение. Применение системы суммирования МР-баллов помогает в диагностике ОМ. Сумма МР-баллов ≥3 в разработанной балльной системе позволяет диагностировать ОМ с высокой чувствительностью (94,1%) и специфичностью (83,3%).

A Case Report of Differential Diagnosis of Causes of Severe Valvular Heart Disease (Takayasu's Arteritis, Infective Endocarditis and Myxomatous Degeneration) with the Key Role of Histological and PCR Examination

Aortic valve lesion is a common and may have diverse causes, from degenerative, congenital and infectious diseases to autoimmune conditions. We present a rare case of Takayasu arteritis and severe heart lesion due to the myxomatous degeneration of the aortic and mitral valves associated with development of infective endocarditis (IE) complicated by abscess, fistula, valve perforation and recurrent acute decompensated heart failure in a young female patient. A combined use of histopathological and PCR analyses of valve tissues was critically important for differential diagnosis of the valve lesions, as it made it possible to identify the true cause of the disease. The presence of Takayasu arteritis has played an indirect role by creating conditions for the development of immunosuppression and determining the disease severity and its progression

Azimuthal asymmetries of charged hadrons produced by high-energy muons scattered off longitudinally polarised deuterons

Azimuthal asymmetries in semi-inclusive production of positive (h^+) and negative hadrons (h^-) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The asymmetries were decomposed in several terms according to their expected modulation in the azimuthal angle phi of the outgoing hadron. Each term receives contributions from one or several spin and transverse-momentum-dependent parton distribution and fragmentation functions. The amplitudes of all phi-modulation terms of the hadron asymmetries integrated over the kinematic variables are found to be consistent with zero within statistical errors, while the constant terms are nonzero and equal for h^+ and h^- within the statistical errors. The dependencies of the phi-modulated terms versus the Bjorken momentum fraction x, the hadron fractional momentum z, and the hadron transverse momentum p_h^T were studied. The x dependence of the constant terms for both positive and negative hadrons is in agreement with the longitudinal double-spin hadron asymmetries, measured in semi-inclusive deep-inelastic scattering. The x dependence of the sin phi-modulation term is less pronounced than that in the corresponding HERMES data. All other dependencies of the phi-modulation amplitudes are consistent with zero within the statistical errors.Comment: 12 pages, 11 Figures; revision 1 signs in Eq 5 corrected, polishe

Leading order determination of the gluon polarisation from DIS events with high-p_T hadron pairs

We present a determination of the gluon polarisation Delta g/g in the nucleon, based on the longitudinal double-spin asymmetry of DIS events with a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam scattering off a polarised ^6LiD target. The gluon polarisation is evaluated by a Neural Network approach for three intervals of the gluon momentum fraction x_g covering the range 0.04 < x_g < 0.27. The values obtained at leading order in QCD do not show any significant dependence on x_g. Their average is Delta g/g = 0.125 +/- 0.060 (stat.) +/- 0.063 (syst.) at x_g=0.09 and a scale of mu^2 = 3 (GeV/c)^2.Comment: 13 pages, 6 figures and 3 table

A new measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target

New high precision measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised 6LiD target are presented. The data were taken in 2003 and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. Both the Collins and Sivers asymmetries turn out to be compatible with zero, within the present statistical errors, which are more than a factor of 2 smaller than those of the published COMPASS results from the 2002 data. The final results from the 2002, 2003 and 2004 runs are compared with naive expectations and with existing model calculations.Comment: 40 pages, 28 figure