具有病例失踪的结核病模型的全局稳定性

建立了一类具有病例失踪的结核病数学模型,定义了模型的基本再生数R0,通过构造适当的Lyapunov函数证明了模型解的渐近性态.证明了当基本再生数小于1时,无病平衡点是全局渐近稳定的;当基本再生数大于1时,唯一的地方病平衡点是全局渐近稳定的.     

罗格列酮治疗内脏脂肪性肥胖2型糖尿病临床观察

目的:观察罗格列酮治疗对2型糖尿病内脏脂肪含量变化.方法:60例内脏脂肪性肥胖2型糖尿病患者随机分为A组、B组各30例,两组体重指数、病程、FIG和餐后2h血糖(2hPG)等资料具有可比性.维持试验前磺脲类降糖药剂量不变,A组加服罗格列酮4mg,1次/d,时间为24W,观察空腹血糖、糖化血红蛋白、胰岛素、内脏脂肪含量的变化.结果:两组空腹血糖、糖化血红蛋白、胰岛素治疗后较治疗前明显下降(P＜0.05);治疗24周后A组内脏脂肪含量显著下降(P＜0.05),B组无明显差异(P＞0.05),2组问存在显著差异(P＜0.05).结论:罗格列酮能减少2型糖尿病的内脏脂肪含量,延缓并发症的发生.     

Wheel running in the rat induced by a fixed-time presentation of water

Four female water-deprived albino rats were given free access to a running wheel and food in baseline sessions with water present for the first 375 sec of each daily 100-min session. In experimental sessions, water was presented intermittently according to a fixed-time (FT) 2-min schedule, which delivered water on a periodic basis independently of the rat’s behavior, resulting in 50 7.5sec presentations of the water tube. Food consumption did not vary as a function of the experimental condition, whereas running increased for all Ss during the schedule conditions. Increases in running appeared to be the result of increases in both initiations of running and run-burst lengths.     

Developing a rat model of dilated cardiomyopathy with improved survival

To compare the continuous infusion and intermittent bolus injection administration protocols of doxorubicin (Dox) under the same cumulative dose (12 mg/kg), and establish a rat dilated cardiomyopathy model with improved survival, a total of 150 Sprague-Dawley (SD) rats were divided into three groups: a control group, administered with normal saline; a Dox 1 group, administration twice a week at 1 mg/kg; a Dox 2, administration once a week at 2 mg/kg. Mortality rates in the Dox 1 and Dox 2 groups were 22% and 48%, respectively (P<0.05). As shown by echocardiography, both Dox groups exhibited significant chamber dilatation and reduced cardiac function (all P<0.05 vs. control). Plasma brain natriuretic peptide and C-reactive protein concentrations were significantly increased (P<0.05) with both Dox regimens. The concentrations of Caspase-3 in myocardial tissues of rats significantly increased in both doxorubicin regimens. Myocardial metabolism imaging by histology and ¹⁸F-fluoro-deoxyglucose-positron emission tomography (¹⁸FDG-PET) both revealed decreased myocardial viability and necrosis, and even interstitial fibrosis, in left ventricles (LVs) in both Dox groups. Serum creatinine and aspartate aminotransferase concentrations were significantly higher in the Dox 2 model than in the Dox 1 model. Doxorubicin given at both regimens induced dilated cardiomyopathy, while its administration at lower doses with more frequent infusions reduced the mortality rate.     

降雨诱发非饱和土边坡直线滑移的稳定性计算

根据Green-Ampt入渗原理,考虑降雨入渗及其对土体的物理力学作用,分析了雨水入渗非饱和土边坡坡面入渗规律,建立了非饱和土边坡坡面入渗模型,获得了雨水非饱和入渗过程中的雨水入渗深度计算式。通过分析降雨后边坡潜在滑移体的几何模型和力学特性,获得了滑移面倾角与边坡倾角、雨水入渗深度和坡高之间的关系,建立了降雨入渗影响下非饱和土边坡直线滑移与倾覆破坏的安全系数计算式,为分析降雨入渗非饱和土边坡稳定性提供了一种定量计算方法。     

未受控制的高血糖对2型糖尿病患者粘附分子的影响（英文）

目的:评估可溶性血管细胞间黏附分子(s VCAM-1)、可溶性细胞间黏附分子(s ICAM-1)、可溶性选择素E和可溶性血栓调节蛋白在血糖控制良好和不受控制的2型糖尿病患者中的水平。创新点:对2型糖尿病患者的血管内皮炎症标记物进行评估。方法:62例糖尿病患者分成两组:第一组包括35个血糖控制良好的糖尿病患者,第二组包括27个未控制血糖并伴有微蛋白尿的糖尿病患者。对照组由25名健康志愿者组成。测定血浆中s VCAM-1、s ICAM-1、可溶性选择素E和可溶性血栓调节蛋白的浓度,同时测定血清肌酐及血浆中空腹血糖和糖化血红蛋白(Hb A1c)的浓度。结论:与血糖控制良好的糖尿病组相比,未控制血糖组具有相对低的ICAM-1水平和更高的VCAM-1水平。未控制血糖组中患者的糖化血红蛋白和ICAM-1之间呈正相关,肾小球滤过率和可溶性选择素E之间呈正相关,而肌酐和ICAM-1之间呈负相关。研究证实2型糖尿病的发病机理中炎症过程的出现与血管内皮功能受损有关。未受控制的高血糖对粘附分子的反向作用表明,在糖尿病的并发症中VCAM-1和ICAM-1具有不同功能。     

A preliminary evaluation of VEGF-A,VEGFR1 and VEGFR2 in patients with well-controlled type 2 diabetes mellitus

Objective

Decompensated chronic hyperglycemia often leads to late microvascular complications such as retinopathy, diabetic foot syndrome, and diabetic kidney disease. The aim of this study was to determine the concentration of vascular endothelial growth factor A (VEGF-A) and its receptors in patients with well-controlled diabetes.

Methods

The study was conducted on 31 patients with well-controlled type 2 diabetes without micro-or macroangiopathy. Thirty healthy volunteers were enrolled in a control group. Serum concentrations of VEGF-A, VEGF receptors 1 and 2 (VEGFR1 and VEGFR2), fasting glucose, and lipid profiles were measured, and the plasma concentration of glycated hemoglobin (HbA1c) was determined.

Results

No significant differences were observed between the concentration of VEGF-A, VEGFR1 or VEGFR2 in the subject group and that in the control group. Positive correlations were noted between the levels of VEGF-A, VEGFR2, and triglyceride, and there was a negative correlation between the levels of VEGFR2 and high-density lipoprotein (HDL)-cholesterol in the study group.

Conclusions

The concentrations of VEGF-A and its receptors 1 and 2 in patients with well-controlled diabetes are comparable to those of healthy individuals, which may indicate that appropriate control of glucose levels delays the occurrence of vascular complications. A negative correlation between VEGFR2 and HDL-cholesterol levels, and positive correlations between VEGF-A, VEGFR2, and triglyceride levels, suggest that lipid abnormalities occurring in diabetes may be involved in the modulation of angiogenesis.     

具多滞量的非自治Logistic方程的3/2稳定性

研究了具无界时滞多滞量的非自治Logistic方程X′(t) +∑mi=1ai(t)〔1+x(t)〕x(t-τi(t) =0的零解的全局渐近稳定性 ,获得了方程的零解为全局渐近稳定的充分条件 ,所得结果推广并改进了许多熟知的结论     

具有时滞和下临界企业竞争模型的稳定性和Hopf分支分析

为了研究下临界和时滞对企业产量的影响,主要考虑具有下临界的企业竞争模型,针对企业生产所产生的生产周期和信息时滞对企业生产产量的影响,将时滞引入具有下临界企业竞争模型中,提出了具有时滞和下临界的企业竞争模型。以时滞为参数,在适当的条件下,得到了系统在内部平衡点处的局部稳定性和产生Hopf分支的条件,发现当参数经过临界值时,企业的生产产量产生周期性震荡。进一步利用中心流形定理和规范型方法,得到分支的方向和周期解的稳定性。最后通过数值模拟验证所得到的结论。结果表明,时滞和下临界能够影响企业产量的稳定性,得到企业产量稳定的临界条件,在一定范围内,企业产量能够保持局部稳定。     

Effect of intensive multifactorial treatment on the intima-media thickness of large arteries in patients with new-onset type 2 diabetes mellitus

Objective  

To quantify the changes in blood glucose, blood lipids, blood pressure, and the intima-media thickness (IMT) of large arteries in patients with new-onset type 2 diabetes mellitus who received either intensive multifactorial treatment or conventional treatment.     

具有扰动的非自治变时滞中立型微分方程的3/2稳定性

本文讨论了一类具有扰动的非自治变时滞中型微分方程的3/2稳定性,得到了方程的零解一致稳定和渐近稳定的充分条件.     

采用Gd2O2S回热填料的带预冷4K斯特林型高频脉管制冷机性能研究

研究目的：研究新型磁性回热填料Gd2O2S对液氦温区高频脉管制冷机多级回热器损失特性的影响。 创新要点：确定了不同回热填料以及运行参数（频率、平均压力）下液氦温区多级脉管制冷机的制冷温度和各级预冷量,进一步明确了4K高频回热损失机理。 研究方法：采用理论研究与实验验证相结合的方法,基于一台两级G-M型低频脉管制冷机预冷的单极斯特林型高频脉管制冷机,研究多级回热器在高频以及4K温区下的损失特性。选取新型回热填料Gd2O2S替代部分回热填料HoCu2,比较回热器采用两种填料时在不吲运行频率及平均压力下的冷端制冷温度（图10）、各级预冷量和预冷温度（图1112）。 重要结论：采用孔隙率较小的新型磁性回热填料Gd2O2S可显著改善第一级回热器内压力波与质量流的相位关系,从而减小该级回热损失。减小平均压力可以降低制冷机无负荷制冷温度并减小第二级预冷量,但制冷工质氦的体积比热容会急剧增大,从而使低温级回热器的换热对频率非常敏感。此外,频率对高温级回热器的回热特性影响不明显。该方法可以为三级斯特林型4K多级脉管制冷机提供设计依据。     

Effects of rosuvastatin on the production and activation of matrix metalloproteinase-2 and migration of cultured rat vascular smooth muscle cells induced by homocysteine

Objective: To test the influence of homocysteine on the production and activation of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2) and on cell migration of cultured rat vascular smooth muscle cells (VSMCs). Also, to explore whether rosuvastatin can alter the abnormal secretion and activation of MMP-2 and TIMP-2 and migration of VSMCs induced by homocysteine. Methods: Rat VSMCs were incubated with different concentrations of homocysteine (50–5 000 μmol/L). Western blotting and gelatin zymography were used to investigate the expressions and activities of MMP-2 and TIMP-2 in VSMCs in culture medium when induced with homocysteine for 24, 48, and 72 h. Transwell chambers were employed to test the migratory ability of VSMCs when incubated with homocysteine for 48 h. Different concentrations of rosuvastatin (10⁻⁹–10⁻⁵ mol/L) were added when VSMCs were induced with 1 000 μmol/L homocysteine. The expressions and activities of MMP-2 and TIMP-2 were examined after incubating for 24, 48, and 72 h, and the migration of VSMCs was also examined after incubating for 48 h. Results: Homocysteine (50–1 000 μmol/L) increased the production and activation of MMP-2 and expression of TIMP-2 in a dose-dependent manner. However, when incubated with 5 000 μmol/L homocysteine, the expression of MMP-2 was up-regulated, but its activity was down-regulated. Increased homocysteine-induced production and activation of MMP-2 were reduced by rosuvastatin in a dose-dependent manner whereas secretion of TIMP-2 was not significantly altered by rosuvastatin. Homocysteine (50–5 000 μmol/L) stimulated the migration of VSMCs in a dose-dependent manner, but this effect was eliminated by rosuvastatin. Conclusions: Homocysteine (50–1 000 μmol/L) significantly increased the production and activation of MMP-2, the expression of TIMP-2, and the migration of VSMCs in a dose-dependent manner. Additional extracellular rosuvastatin can decrease the excessive expression and activation of MMP-2 and abnormal migration of VSMCs induced by homocysteine.     

一类具有Z2-等变性质的平面七次哈密顿向量场的相图（英文）

本文给出了一类具有Z2-等变性质的七次平面哈密顿向量场的全局相图,并对参数空间进行了划分。     

应用醋酸锌作返滴定剂尾数微滴法测定硅石及硅砖中的三氧化二铝

本文通过对操作步骤、滴定、计数、计算四个方面进行研究、改进，提出了Zn（Ac）2作迈滴定剂的尾数微滴法。