307 research outputs found

    Parameters of loading equilibration in a tube cold pilger mill drive

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    On the basis of the variational approach and the Gauss-Seidel method there are proposed a technique and a mathematical model for determining the optimal parameters of dynamic load balancing systems on the crankshaft on the example of the cold rolling mill tube with reciprocating motion of an executive element in the form of a large mass working stand. The most compact scheme with the orthogonal motion of the executive element and the balancing load was chosen as the dynamic balance system. Variable parameters include dezaxial values, misalignment angle of cranks, weight of counterweight and balancing weight, lengths of connecting rods of executive and balancing mechanisms. For the existing series of sizes of cold rolling tube mill as the mass and speed of the rolling stand increase, the proportion of dynamic and technological components of the reduced load and respectively the kinematic scheme of the balancing mechanism changes. In this case, the structure of the loading and a set of variable parameters remain unchanged. Therefore, the proposed mathematical model of dynamic programming retains the universality of finding the minimum of maximum of the resulting load. © Published under licence by IOP Publishing Ltd

    Measurement of the Optical Absorption Spectra of Epitaxial Graphene from Terahertz to Visible

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    We present experimental results on the optical absorption spectra of epitaxial graphene from the visible to the terahertz (THz) frequency range. In the THz range, the absorption is dominated by intraband processes with a frequency dependence similar to the Drude model. In the near IR range, the absorption is due to interband processes and the measured optical conductivity is close to the theoretical value of e2/4e^{2}/4\hbar. We extract values for the carrier densities, the number of carbon atom layers, and the intraband scattering times from the measurements

    Androgen receptor phosphorylation at serine 515 by Cdk1 predicts biochemical relapse in prostate cancer patients

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    <br>Background:Prostate cancer cell growth is dependent upon androgen receptor (AR) activation, which is regulated by specific kinases. The aim of the current study is to establish if AR phosphorylation by Cdk1 or ERK1/2 is of prognostic significance.</br> <br>Methods: Scansite 2.0 was utilised to predict which AR sites are phosphorylated by Cdk1 and ERK1/2. Immunohistochemistry for these sites was then performed on 90 hormone-naive prostate cancer specimens. The interaction between Cdk1/ERK1/2 and AR phosphorylation was investigated in vitro using LNCaP cells.</br><br>Results:Phosphorylation of AR at serine 515 (pAR(S515)) and PSA at diagnosis were independently associated with decreased time to biochemical relapse. Cdk1 and pCdk1(161), but not ERK1/2, correlated with pAR(S515). High expression of pAR(S515) in patients with a PSA at diagnosis of ≤20 ng ml(-1) was associated with shorter time to biochemical relapse (P=0.019). This translated into a reduction in disease-specific survival (10-year survival, 38.1% vs 100%, P<0.001). In vitro studies demonstrated that treatment with Roscovitine (a Cdk inhibitor) caused a reduction in pCdk1(161) expression, pAR(S515)expression and cellular proliferation.</br> <br>Conclusion: In prostate cancer patients with PSA at diagnosis of ≤20 ng ml(-1), phosphorylation of AR at serine 515 by Cdk1 may be an independent prognostic marker.</br&gt

    Mathematical Model of Speed Control System Induction Motor with the Purpose of Increasing its Service Life

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    В статье рассматривается замкнутая система регулирования частоты вращения асинхронного двигателя (АД), пропорционального регулятора и тиристорного преобразователя напряжения (ТПН). Разработана математическая модель регулирования частоты вращения АД, позволяющая снизить потери мощности в установившихся режимах и при допустимых параметрах переходных процессов для режимов холостого хода и малых нагрузок. Математическая модель АД с ТПН описывается в виде полиноминальных зависимостей от режимных параметров. Модель базируется на экспериментальных данных АД различной мощности. Разработана методика оценки эффективного использования электрической энергии в виде коэффициента мощности АД. Определен оптимизированный вариант формы регулировочной характеристики по критерию минимума затрат электрической энергии. Приведены экспериментальные и расчетные данные, даны практические рекомендации.The article deals with a closed system speed control of induction motor (IM), proportional controller and thyristor voltage converter (TVC). A mathematical model of regulation speed of IM, which reduces losses power in steady-state conditions and with permissible parameters of transients for idling and low load. The mathematical model of IM with TVC is described in the form polynomial dependencies on the regime parameters. The model is based on experimental data of IM of different power. Developed by methodology for assessing effective use electrical energy in the form of a power factor IM. An optimized form is defined by the criterion minimum electrical energy costs. Are presented experimental and calculated data are given practical recommendations

    Cerebrovascular complications of hematopoetic stem cell transplantation in patients with hematologic malignancies

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    Introduction. Modern transplantation and biological therapy methods are associated with a wide range of adverse events and complications. Incidence and variety of neurological complications mostly depend on myelo- and immunosuppression severity and duration as well as on donor's and recipient's characteristics. The most frequent complications involving the nervous system include neurotoxic reactions, infections, autoimmune and lymphoproliferative diseases, and dysmetabolic conditions as well as cerebrovascular complications that potentially affect transplantation outcomes. Objective. To evaluate the impact of post-transplantation cerebrovascular events (CVEs) on transplantation outcomes in patients with hematologic malignancies. Materials and methods. We analyzed 899 transplantations performed at the Raisa Gorbacheva Memorial Research Institute for Pediatric Oncology, Hematology, and Transplantation, Pavlov First Saint Petersburg State Medical University, from 2016 to 2018. We assessed transplantation parameters and donor's and recipient's characteristics by intergroup comparison, pseudo-randomization (propensity score matching), KaplanMeier survival analysis, and log-rank tests. Results. Post-transplantatively, CVEs developed in 2.6% (n = 23) of cases: 13 (1.4%) ischemic strokes and 11 (1.2%) hemorrhagic strokes or intracranial hemorrhages were diagnosed. CVEs developed on days 99.5 39.2 post hematopoetic stem cell transplantation (HSCT). There were more patients with non-malignant conditions in the CVE group as compared to the non-CVE group (21.7% vs 7.9%; p = 0.017). Patients with CVE had a significantly lower Karnofsky index (75.6 21.3 vs 85.2 14.9; p = 0.008). Statistically, we also note some non-significant trends: patients with CVE more often underwent allogenic HSCT (82.6% vs 64.0%; p = 0.077) while donors were more often partially (rather than totally) HLA compatible for recipients (39.1% vs 21.1%; p = 0.33). Patients with CVE more often had a history of venous thromboses (13.3% vs 4.2%; p = 0.077). Post-HSCT stroke decreased post-transplantation longevity by approximately 3 times (331.8 81.6 vs 897.9 25.4 post HSCT; p = 0.0001). In the CVE group, survival during first 180 days post HSCT (landmarks post-HSCT Day+60 and Day+180) was significantly lower as compared to that in the CVE-free group. If CVE developed during first 30 days and 100 days post HSCT, vascular catastrophe did not affect post-HSCT survival significantly. Conclusion. Whereas ischemic stroke is a long-term HSCT complication (beyond D+100 post transplantation), hemorrhagic stroke is a short-term complication (D0D+100 post HSCT). CVEs affect survival in patients with hematologic malignancies, especially those developed between D+60 and D+180 post HSCT. History of venous abnormalities, low Karnofsky index at HSCT initiation, and the type of allogenic HSCT, especially from half-matched donors, can be considered as negative outcome risk factors in post-HSCT CVE

    Qualitative analysis of acid-base nutrition and its effect on the human body

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    The purpose of the study to identify the dependence of the psychoemotional state of a person on the acid load in the diet.Цель исследования – выявить зависимость психоэмоционального состояния человека от кислотной нагрузки рациона питания

    Qualitative analysis of acid‑base nutrition and its effect on the human body

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    The purpose of the study to identify the dependence of the psychoemotional state of a person on the acid load in the diet.Цель исследования — выявить зависимость психоэмоционального состояния человека от кислотной нагрузки рациона питания

    Particulate matter Air Pollution induces hypermethylation of the p16 promoter Via a mitochondrial ROS-JNK-DNMT1 pathway

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    Exposure of human populations to chronically elevated levels of ambient particulate matter air pollution < 2.5 μm in diameter (PM2.5) has been associated with an increase in lung cancer incidence. Over 70% of lung cancer cell lines exhibit promoter methylation of the tumor suppressor p16, an epigenetic modification that reduces its expression. We exposed mice to concentrated ambient PM2.5 via inhalation, 8 hours daily for 3 weeks and exposed primary murine alveolar epithelial cells to daily doses of fine urban PM (5 µg/cm2). In both mice and alveolar epithelial cells, PM exposure increased ROS production, expression of the DNA methyltransferase 1 (DNMT1), and methylation of the p16 promoter. In alveolar epithelial cells, increased transcription of DNMT1 and methylation of the p16 promoter were inhibited by a mitochondrially targeted antioxidant and a JNK inhibitor. These findings provide a potential mechanism by which PM exposure increases the risk of lung cancer
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