Matlab在经济管理中的应用

Matlab是功能强大的计算机软件，它在自动控制、机电和土木工程以及经济管理领域有着广泛的应用．我们给出了扩展的指派问题，且证明了该问题与原指派问题的最优值相同，然后利用Matlab语言，得到了指派问题的Matlab算法，对运输问题也给出了该问题的Matlab算法．计算实例表明，新的解题方法，既简易又精确．     

HNS型三相分离器的应用

在分析HNS型三相分离器工作原理及结构的基础上，通过现场实际应用测试，指出该设备油气水分离系统运行平衡，对含水率在80％以上的产出液，经该设备脱气，脱水处理后，原油含水率低于0．38％，水中含油低于300mg/L，完全能达到设计指标。     

不同环境条件下几种高寒草甸植物的非克隆繁殖投入和生长

通过对高寒草甸生态系统金露梅灌丛、矮嵩草草甸、围栏矮嵩草草甸以及模拟地球增温效应下5种植物繁殖投入和生长特性的测定,结果表明,矮嵩草、麻花艽、苔草以及美丽风毛菊的叶长沿对照矮嵩草草甸、0TC、围栏以及金露梅灌丛呈现上升趋势,只是灌丛中苔草和麻花艽两种植物的叶长较围栏和OTC有所下降,而环境变化对植物的叶宽的影响较小。苔草在金露梅灌丛中的繁殖投入最大,其次是矮嵩草草甸和围栏,OTC中苔草的繁殖投入几乎为零。围栏与矮嵩草草甸内苔草的繁殖投入差异不显著,而两者中植物的繁殖投入与金露梅灌丛相比,差异性显著(P<0.05)。矮火绒草在矮嵩草草甸中的繁殖投入最大,其次是0Tc和围栏,灌丛中矮火绒草的繁殖投入最小。OTC与矮嵩草草甸内矮火绒草的繁殖投入差异不显著,而OTC与围栏中矮火绒草的繁殖投入差异性显著(P<0.05)。由此我们可以得出一个结论:繁殖投入随环境梯度的变化,反映了植物繁殖对策和繁殖投入在整个生活史特征中的可塑性。     

一类时滞微分系统有界解的收敛性

研究了一类时滞微分系统解的渐近性态．在一些比已有文献通常附加的局部李普希兹条件更弱的条件下，证明了此系统的每个有界解趋于某平衡态．我们的结果推广了已有的一些结论．     

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AIM: To investigate the contribution of angiotensin-converting enzyme inhibitor (ACEI) to the regulation of calpain system in infarcted myocardium. METHODS: Rat myocardial infarction (MI) model was established by permanent ligation of the left coronary artery. The treatment with the ACEI inhibitor rampril (1 mg·kg-1·d-1) was started 7 days prior to surgery. On day 1, 3, 7 and 14 after MI, protein levels of calpainⅠ, Ⅱ and calpastatin were determined in left ventricular free wall (LVFW), interventricular septum (IS) and right ventricule. RESULTS: CalpainⅠprotein level was increased in IS 14 d post MI, whereas the protein level of calpainⅡ was maximally increased in LVFW 3 d post MI. Rampril decreased protein up-regulation of calpainⅠ and Ⅱ, and reduced infarct size and interstitial fibrosis. Calpastatin protein expression was not affected by ACEI. CONCLUSIONS: CalpainⅠ is involved in cardiac remodelling in the late and calpainⅡ contributes to cardiac tissue damage in the early phase of MI. The heart protective effect of ACEI may be related to the inhibition of calpain system in the pathogenesis of myocardial infarction.     

Effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells from rats exposed to chronic hypoxia

AIM: To investigate the effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells (PASMCs) from rats exposed to chronic hypoxia. METHODS: (1) Wistar rats were randomly divided into control group (group A) and chronic hypoxia group (group B). Then group B received hypoxia 8 hours per day for 4 consecutive weeks. (2) Single PASMC was obtained via acute enzyme separation method. (3) Conventional whole-cell patch clamp technique was used to record resting membrane potential (Em) and ion currents of voltage-gated potassium channel. The changes of ion currents of voltage-gated potassium channel before and after applying cGMP (1 mmol/L), an agonist of protein kinase G (PKG), and cGMP plus H-8 (1 mmol/L), an inhibitor of PKG were compared between two groups. RESULTS: The Em of group B were significantly lower than that of group A. The ion currents of voltage-gated potassium channel in group A and group B were all significantly inhibited by cGMP [control group: from (118.0±5.0) pA/pF to (89.9±16.5) pA/pF, n=6, P＜0.05;chronic hypoxia group: from (81.0±5.0) pA/pF to (56.8±9.1) pA/pF, n=6, P＜0.05]and these effects were reversed by H-8 [control group: from (119.2±10.3) pA/pF to (117.8±9.1) pA/pF, n=6, P＞0.05;chronic hypoxia group: from (96.8±6.2)　pA/pF to (98.0±2.2)　pA/pF, n=6, P＞0.05]. CONCLUSIONS: The currents of voltage-gated potassium channel was inhibited by chronic hypoxic. The inhibitory effect of cGMP on currents of voltage-gated potassium channel in PASMCs from both normal and chronic hypoxic rats may be probably through the phosphorylation of voltage-gated potassium channel.     

富铁酵母对家兔红细胞免疫功能的影响

为探讨富铁酵母对家兔红细胞免疫功能的影响,将32只家免随机分成富铁酵母高、低剂量组,FeSO4组及空白对照组,分别灌服富铁酵母(Fe元素8 mg/kg、4 mg/kg)、FeSO4(Fe元素4 mg/kg)及空白生理盐水;连续5 d后,检测红细胞C3g受体花环率和复合物(IC)花环率.结果:富铁酵母较FeSO4及空白组能显著提高红细胞C3h受体花环和红细胞复合物(IC)花环的百分率,但高、低剂量间无显著性差异.结论:富铁酵母能显著提高红细胞免疫功能.     

Role of potassium channels in the regulation of intracellular free Ca2+ concentration of pulmonary artery smooth muscle cells in rats

AIM: To investigate the role of potassium channels in the regulation of intracellular free calcium concentration ( [Ca²⁺]_i) of pulmonary artery smooth muscle cells (PASMCs) in rats. METHODS: The fluorescence Ca²⁺ indicator Fura-2/AM was used to observe [Ca²⁺]_i of rat PASMCs in normal and chronic hypoxic condition. The influences of potassium channels on PASMCs proliferation were assessed by MTT assay. RESULTS: 1. In normoxic condition, [Ca²⁺]_i was (156.91±8.60) nmol/L, and in hypoxic condition, [Ca²⁺]_i was (294.01±16.81) nmol/L. 2. In normoxic condition, the voltage-dependent K⁺-channel antagonist 4-aminopyridine (4AP), but not the Ca²⁺-activated K⁺-channel antagonist tetraethylammonium (TEA) and the ATP-sensitive K⁺-channel antagonist glibenclamide (Glib) increased [Ca²⁺]_i. 3. In hypoxic condition, 4AP and TEA caused the rise in [Ca²⁺]_i , but Glib had no effect on [Ca²⁺]_i. 4. MTT assay showed that 4AP increased the value of absorbing light degree (A value) in normoxic and hypoxic condition (0.582±0.062,0.873±0.043,respectively, P＜0.01), TEA increased A value only in hypoxic condition, and Glib had no effect on the proliferation of PASMCs. CONCLUSIONS: K_V plays an important role in the regulation of [Ca²⁺]_i and proliferation of PASMCs. K_Ca serves as distinct responsive roles in the regulation of proliferation of PASMCs in hypoxic condition. K_ATP has no effect on [Ca²⁺]_i and proliferation of PASMCs in normoxic and hypoxic conditions.