ВОЗМОЖНОСТИ ИССЛЕДОВАНИЯ СВЕРХЗВУКОВОГО ОБТЕКАНИЯ ПРОФИЛЯ ВБЛИЗИ ЭКРАНА МЕТОДОМ ГИДРАВЛИЧЕСКОГО АНАЛОГОВОГО МОДЕЛИРОВАНИЯ

Supersonic flow around the system of bodies (lattice wings, a wing near the shielding surface, blades of supersonic stages of the compressor, etc.) is accompanied by complex pictures of shock waves, which depend on several parameters characterizing the mutual arrangement, the bodies of their external shapes and sizes, as well as the Mach number. These patterns are determined by the nature of the interaction of the head shock wave and the shock wave on the lower surface of the profile, caused by a change in the flow direction as a result of deflection of the flap.The paper presents the results of an investigation of supersonic flow around a profile with a flap near the screen, obtained using the method of hydraulic analog simulation (the method of gas-hydraulic analogy). This method is based on the analogy of the equations of motion describing a planar gas flow and a thin liquid layer and is used in solving a large class of plane problems of stationary and nonstationary gas dynamics.The parameters that affect the structure of the flow around the profile near the screen are: the Mach number of the profile movement with the values M∞ = 1.4 ÷ 1.9; relative distance of the profile from the screen with the values Нз = 0.2 ÷ 1.0; angle of flap deflection with values δз = 0 ÷ 40°. In the course of the experimental investigation, the changes in the structure of shock waves were determined and the influence of the above-mentioned parameters on the process was revealed. The results of the experimental study are presented in the form of graphical dependencies of the relative position of the shock wave on the lower surface of the profile for different Mach numbers, the relative position of the profile from the screen, and the angle of deflection of the flap Δ = f (М∞,Нз , δз). On the basis of the analysis of the obtained dependences, a generalized parameter is derived, which makes it possible to determine the boundaries of changes in the structure of shock waves in a given type of problem.Сверхзвуковое обтекание системы тел (решетчатые крылья, крыло вблизи экранирующей поверхности, лопатки сверхзвуковых ступеней компрессора и т.п.) сопровождается сложными картинами скачков уплотнения, которые зависят от нескольких параметров, характеризующих взаимное расположение тел, их внешних форм и размеров, а также величины числа Маха. Эти картины определяются характером взаимодействия головного скачка уплотнения и скачка уплотнения на нижней поверхности профиля, вызванного изменением направления течения в результате отклонения закрылка.В статье представлены результаты исследования сверхзвукового обтекания профиля с закрылком вблизи экрана, полученные с использованием метода гидравлического аналогового моделирования (метод газогидравлической аналогии). Этот метод основан на аналогии уравнений движения, описывающих плоское течение газа и тонкого слоя жидкости, и применяется при решении большого класса плоских задач стационарной и нестационарной газовой динамики.Параметрами, влияющими на структуру обтекания профиля вблизи экрана, являются: число Маха движения профиля со значениями М∞= 1,4 ÷ 1,9; относительное отстояние профиля от экрана со значениями Нз= 0,2 ÷ 1,0; угол отклонения закрылка со значениями δз = 0 ÷ 40°. В процессе экспериментального исследования определены изменения структуры скачков уплотнения и выявлено влияние на данный процесс вышеперечисленных параметров. Результаты экспериментального исследования представлены в виде графических зависимостей относительного положения скачка уплотнения на нижней поверхности профиля при различных значениях числа Маха, относительного положения профиля от экрана и угла отклонения закрылка Δ = f (М∞,Нз, δз). На основании анализа полученных зависимостей выведен обобщенный параметр, позволяющий определять границы изменения структуры скачков уплотнения в данном типе задач.

Thymosin Beta 4 Prevents Oxidative Stress by Targeting Antioxidant and Anti-Apoptotic Genes in Cardiac Fibroblasts

Thymosin beta-4 (Tβ4) is a ubiquitous protein with diverse functions relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory responses. The effecter molecules targeted by Tβ4 for cardiac protection remains unknown. The purpose of this study is to determine the molecules targeted by Tβ4 that mediate cardio-protection under oxidative stress.Rat neonatal fibroblasts cells were exposed to hydrogen peroxide (H(2)O(2)) in presence and absence of Tβ4 and expression of antioxidant, apoptotic and pro-fibrotic genes was evaluated by quantitative real-time PCR and western blotting. Reactive oxygen species (ROS) levels were estimated by DCF-DA using fluorescent microscopy and fluorimetry. Selected antioxidant and antiapoptotic genes were silenced by siRNA transfections in cardiac fibroblasts and the effect of Tβ4 on H(2)O(2)-induced profibrotic events was evaluated.Pre-treatment with Tβ4 resulted in reduction of the intracellular ROS levels induced by H(2)O(2) in the cardiac fibroblasts. This was associated with an increased expression of antioxidant enzymes Cu/Zn superoxide dismutase (SOD) and catalase and reduction of Bax/Bcl(2) ratio. Tβ4 treatment reduced the expression of pro-fibrotic genes [connective tissue growth factor (CTGF), collagen type-1 (Col-I) and collagen type-3 (Col-III)] in the cardiac fibroblasts. Silencing of Cu/Zn-SOD and catalase gene triggered apoptotic cell death in the cardiac fibroblasts, which was prevented by treatment with Tβ4.This is the first report that exhibits the targeted molecules modulated by Tβ4 under oxidative stress utilizing the cardiac fibroblasts. Tβ4 treatment prevented the profibrotic gene expression in the in vitro settings. Our findings indicate that Tβ4 selectively targets and upregulates catalase, Cu/Zn-SOD and Bcl(2), thereby, preventing H(2)O(2)-induced profibrotic changes in the myocardium. Further studies are warranted to elucidate the signaling pathways involved in the cardio-protection afforded by Tβ4

Malnutrition as assessed by nutritional risk index is associated with worse outcome in patients admitted with acute decompensated heart failure: an ACAP-HF data analysis

Malnutrition is common at hospital admission and tends to worsen during hospitalization. This controlled population study aimed to determine if serum albumin or moderate and severe nutritional depletion by Nutritional Risk Index (NRI) at hospital admission are associated with increased length of hospital stay (LOS) in patients admitted with acute decompensated heart failure (ADHF). Serum albumin levels and lymphocyte counts were retrospectively determined at hospital admission in 1740 consecutive patients admitted with primary and secondary diagnosis of ADHF. The Nutrition Risk Score (NRI) developed originally in AIDS and cancer populations was derived from the serum albumin concentration and the ratio of actual to usual weight, as follows: NRI = (1.519 × serum albumin, g/dL) + {41.7 × present weight (kg)/ideal body weight(kg)}. Patients were classified into four groups as no, mild, moderate or severe risk by NRI. Multiple logistic regressions were used to determine the association between nutritional risk category and LOS

Development and validation of dissolution method for carvedilol compression-coated tablets

The present study describes the development and validation of a dissolution method for carvedilol compression-coated tablets. Dissolution test was performed using a TDT-06T dissolution apparatus. Based on the physiological conditions of the body, 0.1N hydrochloric acid was used as dissolution medium and release was monitored for 2 hours to verify the immediate release pattern of the drug in acidic pH, followed by pH 6.8 in citric-phosphate buffer for 22 hours, to simulate a sustained release pattern in the intestine. Influences of rotation speed and surfactant concentration in medium were evaluated. Samples were analysed by validated UV visible spectrophotometric method at 286 nm. 1% sodium lauryl sulphate (SLS) was found to be optimum for improving carvedilol solubility in pH 6.8 citric-phosphate buffer. Analysis of variance showed no significant difference between the results obtained at 50 and 100 rpm. The discriminating dissolution method was successfully developed for carvedilol compression-coated tablets. The conditions that allowed dissolution determination were USP type I apparatus at 100 rpm, containing 1000 ml of 0.1N HCl for 2 hours, followed by pH 6.8 citric-phosphate buffer with 1% SLS for 22 hours at 37.0 ± 0.5 ºC. Samples were analysed by UV spectrophotometric method and validated as per ICH guidelines.O presente estudo descreve o desenvolvimento e a validação de método de dissolução para comprimidos revestidos de carvedilol. O teste de dissolução foi efetuado utilizando-se o aparelho para dissolução TDT-06T. Com base nas condições fisiológicas do organismo, utilizou-se ácido clorídrico 0,1 N como meio de dissolução e a liberação foi monitorada por 2 horas para se verificar o padrão de liberação imediata do fármaco em condições de pH baixo, seguidas por pH 6,8 em tampão cítrico-fosfato por 22 horas, para simular o padrão de liberação controlada no intestino. Avaliou-se a influência da velocidade de rotação e a concentração de tensoativo no meio. As amostras foram analisadas por método espectrofotométrico UV-visível validado, em 286 nm. O laurilsulfato sódico a 1% (SLS) mostrou-se ótimo para aumentar a solubilidade do carvedilol em pH 6,8 em tampão cítrico-fosfato. A análise da variância não mostrou diferença significativa entre os resultados obtidos a 50 e a 100 rpm. O método da dissolução discriminante foi desenvolvido com sucesso para os comprimidos revestidos de carvedilol. As condições que permitiram a determinação da dissolução foram: aparelho USP tipo I a 100 rpm, contendo 1000 mL de HCL 0,1 N por 2 horas, seguido de pH 6,8 com tampão cítrico-fosfato, com 1% de SLS por 22 horas a 37,0 ± 0,5 ºC. Amostras foram analisadas por método espectrofotométrico e validadas pelas normas ICH

THE POSSIBILITY OF STUDYING SUPERSONIC FLOW PROFILE CLOSE TO THE SCREEN BY THE METHOD OF HYDRAULIC ANALOG MODELING

Supersonic flow around the system of bodies (lattice wings, a wing near the shielding surface, blades of supersonic stages of the compressor, etc.) is accompanied by complex pictures of shock waves, which depend on several parameters characterizing the mutual arrangement, the bodies of their external shapes and sizes, as well as the Mach number. These patterns are determined by the nature of the interaction of the head shock wave and the shock wave on the lower surface of the profile, caused by a change in the flow direction as a result of deflection of the flap.The paper presents the results of an investigation of supersonic flow around a profile with a flap near the screen, obtained using the method of hydraulic analog simulation (the method of gas-hydraulic analogy). This method is based on the analogy of the equations of motion describing a planar gas flow and a thin liquid layer and is used in solving a large class of plane problems of stationary and nonstationary gas dynamics.The parameters that affect the structure of the flow around the profile near the screen are: the Mach number of the profile movement with the values M∞ = 1.4 ÷ 1.9; relative distance of the profile from the screen with the values Нз = 0.2 ÷ 1.0; angle of flap deflection with values δз = 0 ÷ 40°. In the course of the experimental investigation, the changes in the structure of shock waves were determined and the influence of the above-mentioned parameters on the process was revealed. The results of the experimental study are presented in the form of graphical dependencies of the relative position of the shock wave on the lower surface of the profile for different Mach numbers, the relative position of the profile from the screen, and the angle of deflection of the flap Δ = f (М∞,Нз , δз). On the basis of the analysis of the obtained dependences, a generalized parameter is derived, which makes it possible to determine the boundaries of changes in the structure of shock waves in a given type of problem