A Coupled FEM-BEM Approach for the Solution of the Free-Boundary Axi-Symmetric Plasma Equilibrium Problem

In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.     

21 d-6°头低位卧床期间运动训练对动态姿态平衡的影响

目的探讨21 d-6°头低位卧床和卧床运动训练对动态姿态平衡和控制功能的影响. 方法 10名健康男性青年被试者分为卧床对照组和卧床训练组,每组5人,卧床期间训练组每天进行2次、每次30 min逐级增加负荷的头低位功率自行车训练;分别于卧床前和卧床后21 d进行了动态姿态平衡和双膝等速肌力的测试. 结果与卧床前相比,对照组动态本体感觉得分和运动控制适应能力明显降低,双膝相对峰力矩明显降低,同时伴有腘绳肌与股四头肌峰力矩屈/伸比值的明显增加;训练组动态本体感觉得分和运动控制适应能力明显高于对照组,而腘绳肌与股四头肌峰力矩屈/伸比值无明显改变. 结论 21 d-6°头低位卧床运动训练能够明显改善卧床后动态姿态平衡及其动态运动适应功能.     

用化学计量法研究CO2—n—C7H16系的高压相平衡

测定了在温度３１０．６５Ｋ、３２３．１５Ｋ和压力３．１３～７．５４ＭＰａ条件下的气液平衡数据，实验结果与文献值具有较好的一致性。用ＴＲＫ状态方程对实验所得数据进行关联，取得了较满意的结果。     

1,1,1,2—四氟乙烷—1,1—二氟乙烷二元系恒温汽液相平衡

采用静态蒸汽总压法实验装置，在２９．９４℃、３９．９２℃和４９．９３℃下，测定了１，１，１，２－四氟乙烷－１，１－二氟乙烷二元系汽液相平衡时的物料，总量、系统组成、蒸汽总压和汽相体积。结合物料衡算和Ｔ、Ｐ、ｘ推算ｙ的曲面样条函数法，计算出对应的平衡汽液相组成。用改进的ＰＲ状态方程和一个与温度无关的可调相互作用参数关联了实验数据。     

淋巴细胞β受体与放射配基结合所需孵育时间的确定

介绍理论运算和实验测量相结合，确定淋巴细胞膜碎片β受体与标记配基结合所需平衡时间的方法。结果表明：二种方法所得平衡时间基本一致。多点法时平衡时间需25-30min；单点法时需5-7min。     

Drug-Biomacromolecule Interaction XII: Comparative binding study of sulfaethidole to bovine serum albumin by equilibrium dialysis,fluorescence probe technique,uv difference spectrophotometry and circular dichroism

Binding of sulfaethidole to bovine serum albumin was studied by equilibrium dialysis, fluorescence probe technique, uv difference spectrophotometry and circular dichroism. Equilibrium dialysis method enabled us to estimate the total number of drug binding sites of albumin molecule. For sulfaethidole, albumin had 6 primary and 40 secondary binding sites. The primary and secondary binding constants were 0.9×10⁵ M⁻¹ and 0.2×10⁶ M⁻¹, respectively. 1-Anilino-8-naphthalenesulfonate (ANS) and 2-(4′-hydroxylbenzeneazo)-benzoic acid (HBAB) were used as the fluorescence probe and the uv spectrophotometric probe, respectively. In fluorescence probe technique, results indicated that the number of higher affinity drug binding site of albumin was 1 and the number of lower affinity drug binding sites of albumin was 3, and the primary and secondary drug binding constants for bovine serum albumin were 2.15×10⁵ M⁻¹ and 1.04×10⁵ M⁻¹, respectively. In uv difference spectrophotometry, binding sites were 3 and binding constant was 1.88×10⁵ M⁻¹. The above results suggest that several different methods should be used in ompensation for insufficient information about drug binding to albumin molecule given by only one method.     

Amplified fragment length polymorphism analysis of the VNTR locus D1S80 in central Spain

Summary The polymorphism of the D1S80 locus has been analyzed in a population sample of 203 unrelated individuals living in Madrid (central Spain) by PCR and subsequent semi-dry discontinuous polyacrylamide gel electrophoresis (Tris-chloride/Tris-glycine buffer system) followed by silver staining, The electrophoretic system described in this study offers high resolution in the separation of the different D1S80 alleles allowing the detection of microvariability around the allele T22 in the spanish population. Twenty different alleles containing 17–40 repeats of the basic 16bp unit were distinguished. The alleles T18 and T24 were found to be relatively common in Spain, as in other populations:, with frequencies of 0.224 and 0.372, respectively. No evidence of significant deviations from Hardy-Weinberg equilibrium was found in these preliminary population data.     

新型阳离子(苯乙烯—丙烯酰胺)共聚物的研究 Ⅱ.阳离子(苯乙烯——丙烯酰胺)共聚物与染料的相互作用

以P(St-Am·MG)对染料活性艳红(X-3B)溶液进行絮凝试验,考察了高聚物剂量及外加盐对絮凝效果的影响,并与无疏水基团的阳离子聚丙烯酰胺PAm·MG的絮凝能力进行了比较。发现絮凝体系无外加盐时,高聚物与染料的作用主要是通过静电力;有外加盐时,高聚物的电荷受到屏蔽,高分子链卷曲,PAm·MG的絮凝效果受到较大影响。而P(St-Am·MG)与X-3B之间存在疏水相互作用,受影响较小,此时P(St-Am·MG)的絮凝性能优于PAm·MG。用平衡渗析法研究了不同温度时甲醇和脲存在下P(St-Am·MG)与X-3B相互作用的热力学。证明了它们之间确实存在疏水相互作用。     

Modelling HA protein-mediated interaction between an influenza virus and a healthy cell: pre-fusion membrane deformation.

We present a mathematical model for pre-fusion interaction between an influenza virus and a healthy cell. Our model describes the role played by hemagglutinin (HA) protein clusters in bringing the viral membrane into close contact with the host cell membrane as a first step of the fusion process between the two membranes. The viral membrane is modelled as a lipid bilayer with bending rigidity. Using the calculus of variations, we compute the deformation of the viral membrane under the influence of HA protein clusters. Our numerical results support the hypothesis of dimple formation in the fusion site proposed in the literature. The asymmetric nature of the protein molecules due to various reasons such as tilting is the primary cause for the dimple formation. We discuss the effects of spontaneous curvature, the protein cluster radius, fusion-site size and the bending moment exerted by the protein cluster. We also examine the effects of membrane tension and the presence of a host cell on the dimple shape. Our results support previous experimental observations.     

Myocardial oxygen extraction and oxygen-hemoglobin equilibrium curve during moderate exercise

Summary Conditions of oxygen extraction by the myocardium have been studied in 12 subjects (44±9 years old) with pure mitral stenosis without clinical, metabolic or electrical sign of coronary insufficiency.Oxygen-hemoglobin equilibrium curves (OHEC) have been determined on arterial, mixed venous and coronary sinus blood, at rest and during a moderate (60 W, 10 min) exercise performed on a bicycle ergometer in supine position. Physiological values, at rest and during exercise, of the following functional parameters of the OHEC were determined in the in-vivo conditions of pH and P_CO2P₅₀, n_Hill, DS max = maximal value of OHEC slope (DS=S_O2/P_O2), P_{DS max}, S_{DS max}. The concentration of plasma electrolytes capable to modify one of these parameters was controlled in each blood sample.In coronary sinus blood, P₅₀ rises from 27.5±1.7 to 28.9±1.6 Torr during exercise (p<0.01). At rest, Hill's n in myocardial venous blood (2.67±0.09) is significantly higher than in arterial blood (2.61±0.08, p<0.01). A decrease in DS max (2.67±0.20 to 2.53±0.12%. Torr^–1; p<0.01) and an increase in P_{DS max} (20.9±1.9 to 22.6±2.1 Torr, p<0.01) are observed. At rest, the myocardial venous point (PcsO₂, ScsO₂) is not significantly distinct from the maximal slope point (P_{DS max}, S_{DS max}). After 1 min of exercise, a small gap appears which becomes significant at the end of the exercise (P_{DS max}-PcsO₂=0.2 Torr at rest, 2.7 Torr after exercise; S_{DS max}-ScsO₂=4.1% at rest, 7.9% after exercise). DS value at the myocardial venous point is only 2% at rest and 6% after exercise, lower than its maximal value.The gap between venous point and DS max point could constitute an error signal in the regulation loop of the coronary circulation. The existence of a physiological receptor, sensitive to instant variations in myocardial tissue P_O2 and able to maintain venous point near DS max point could be considered.