Polynomial matrix solution of H2 optimal control problem for state‐space systems

A polynomial matrix solution to the H₂ output feedback optimal control problems is obtained for systems represented in state‐equation form. The proof does not invoke the separation principle but is obtained in the z‐domain. The cost function includes weighted states, which allows the so‐called standard system model problem to be solved. This encompasses the class of inferential control problems. The results also enable the two‐degree‐of‐freedom optimal control solution properties to be explored. Copyright © 2002 John Wiley & Sons, Ltd.     

人皮质骨矿化基质中骨盐框架结构

目的：研究人皮质骨矿化基质中骨盐的框架结构及框架中骨微间隙。方法：应用透射电镜、场发射扫描电镜观察、电脑图像分析及能谱分析，分析无骨病成人长骨、扁骨２００例骨盐分布特征。结果：骨盐框架结构由微柱、微梁、微小梁、弓状梁、致密点、隔板和骨微间隙构成。骨微间隙由洞、内衬和壁组成，洞平均直径为８４．４±７５．６ｎｍ，与骨小管相比有显著差异（Ｐ值＜０．００１），平均密度为１１～１７个／μｍ２，与骨小管之比超过１０：１。骨盐分针形结晶和微颗粒结晶。结论：骨盐框架结构及骨微间隙是骨盐在人皮质骨矿化基质中的存在形式，可能与骨盐吸收、沉着有关。     

ERK信号传导通路调控乙醛刺激的肝星状细胞Na+/Ca2+泵mRNA表达的研究

目的 :探讨Erk信号传导通路调控乙醛刺激的肝星状细胞 (HSC)Na /Ca2 泵mRNA表达的影响。方法 :用链霉蛋白酶和胶原酶原位灌流 ,Metrizamide密度梯度离心分离大鼠肝星状细胞 ,采用RT PCR测定PD980 5 9阻断乙醛激活的肝星状细胞Erk活性后Na /Ca2 泵mRNA表达。结果 :乙醛刺激后 ,HSC后明显促进Na /Ca2 泵mRNA表达 (P<0 0 1) ,不同剂量PD980 5 9对肝星状细胞Na /Ca2 泵mRNA表达的影响无统计学意义。结论 :Erk信号传导通路可能对乙醛刺激的肝星状细胞激活状态的启动无明显影响     

肝纤维化组织中MMP1、TIMP1的表达及其临床意义

目的 :检测肝纤维化组织中基质金属蛋白酶 1 (MMP1 )、基质金属蛋白酶组织抑制因子 1 (TIMP1 )的表达 ,为肝纤维化的诊治提供重要的分子生物学指标。 方法 :采用链霉菌抗生物蛋白 -过氧化酶联接法 (S- P法 )检测70例肝纤维化组织中 MMP1 、TIMP1 的表达。结果:(1) TIMP1 蛋白阳性表达随肝纤维化程度的加重而增强 ,并且呈正相关关系 (r=0 .92 74 ,P <0 .0 1)。 (2 ) MMP1 蛋白阳性表达随肝纤维化程度的加重无明显变化 ,无相关关系(r =0 .2 181,P >0 .0 5 )。 结论:TIMP1 与肝纤维化的发生、发展密切相关 ,随纤维化发生、发展阳性表达增强。从分子水平对肝纤维化、肝硬化病变进行评估 ,为早期诊治肝纤维化和判断预后提供依据。     

分娩时子宫下段MMP-9及其组织抑制剂TIMP-1的变化

目的:探讨基质金属蛋白酶(MMP)及其组织抑制剂(TIMP)在分娩发动、宫颈成熟和扩张中的作用和机制.方法:采用ELISA方法测定子宫下段组织中MMP-9和TIMP-1的浓度.有宫缩剖宫产组56例,其中第一产程组44例,第二产程组12例.以无宫缩剖宫产组16例为对照组.结果:有宫缩剖宫产组子宫下段组织中MMP-9和TIMP-1的浓度分别明显高于无宫缩剖宫产组(P<0.05,P<0.05).第一产程组中随宫口开大,MMP-9和TIMP-1的浓度各组间无显著性差异.第二产程组MMP-9和TIMP-1的浓度分别明显高于第一产程组(P<0.01,P<0.05).结论:MMPs和TIMPs的动态变化是分娩发动、宫颈成熟和扩张过程中的重要中间环节.     

MMP-2、TIMP-2在内毒素诱导性葡萄膜炎中的表达

目的　探讨基质金属蛋白酶 2 (MMP 2 )及其组织型抑制剂 (TIMP 2 )在内毒素诱导性葡萄膜炎 (EIU)模型中的表达及意义。方法　 2 0 0 μg伤寒杆菌内毒素注射于SD大鼠双后足垫 ,建立EIU模型。用免疫组织化学方法检测MMP 2、TIMP 2在内毒素注射后不同时间点 (0、 6、 12、 18、 2 4、 4 8、 72、 96h和 7d)的表达。结果　内毒素注射后 6h开始出现炎症 ,于 2 4h炎症达到高峰 ,以后逐渐减轻 ,7d时基本消退。虹膜、睫状体的上皮细胞和渗出的炎性细胞表达MMP 2和TIMP 2。MMP 2在 6h表达开始增高 ,18～ 2 4h达高峰 ,以后逐渐下降。TIMP 2于 12h出现表达 ,4 8h达高峰 ,以后逐渐下降。TIMP 2和MMP 2平均吸光度值的比值与炎症程度呈负相关。结论　MMP 2是与炎症反应相关的调节因子 ,其过量表达参与葡萄膜炎的发病。减低MMP 2的活性或降低MMP 2 /TIMP 2的比值可能为治疗葡萄膜炎的新思路。     

Calcium incorporation in cultured chondroblasts perturbed by an electromagnetic field

We tested the hypothesis that electric perturbation influences 45Ca incorporation in extracellular matrix (ECM) of cartilage in vitro. Hypertrophic chondroblasts of tibial epiphyses (HC), sternum (SC), and skin fibroblasts (F) were cultured from chick embryos. HC, SC, and F cells were micromass seeded three times per week and maintained at 37.5 degrees C with 5% CO2 for two weeks. Cultures were randomly designated control (C) or exposed (E) to a pulsed electromagnetic field (PEMF). A time course experiment of calcium incorporation for all cultured groups showed that 24 h of exposure produced the largest biological response in chondroblasts. Calcium incorporation required supplemental phosphate. Autoradiography data indicated that the calcium incorporation into macromolecules largely occurred in the ECM. 45Ca steady-state perturbation was enhanced by Streptomyces hyaluronidase (SH) but not by testicular hyaluronidase (TH). 45Ca incorporation experiments tested the effects of phosphate, SH, TH, and PEMF alone and in various combinations on these cultures. Only PEMF or SH plus PEMF with phosphate enhanced 45Ca incorporation. Other experiments examined the effect of rotenone or freeze-thawing on cells exposed to PEMF. PEMF plus freeze-thaw enhanced calcium incorporation in HC only. PEMF appeared to cause disruption of the ECM, enhancing the probability of matrix calcification.     

不同试剂脱除猪主动脉瓣细胞的对比研究

目的 用不同方法去除猪主动脉瓣的细胞并比较效果，为组织工程瓣膜提供良好的实验材料。方法 采用十二烷基硫酸钠（SDS）、脱氧胆酯酸钠（SD）、曲拉通（Triton）X-100制备猪主动脉瓣脱细胞基质。标本进行大体、光镜、电镜观察，DNA提取、力学性能的检测并比较。结果 SD无法完全脱除主动脉瓣瓣根内的细胞。TritonX-100和SDS可以完全脱除瓣膜细胞。TritonX-100较好的保持了主动脉瓣胶原纤维和弹性纤维的原有排列和分布，并有较好的力学性能。而SDS对瓣叶和瓣根血管壁中的纤维支架都造成了一定的损伤。SDS和TritonX-100脱细胞时间无明显差别。结论 TritonX-100可以成功脱除猪主动脉瓣细胞，并较好的保持了主动脉瓣的结构和力学性能。     

Acute volaemic changes modify the gastroduodenal resistance to the flow of saline in anaesthetized dogs

The effect of acute and sequential volaemic changes on the gastroduodenal flow of saline was assessed in 23 anaesthetized dogs following two different experimental protocols. Hypervolaemia, by i. v. infusion of saline, induced a gradual decrease on gastroduodenal flow which amounted to 76% below control values (P < 0.001) when volaemic expansion attained 5% of body weight. This effect was volume dependent (17% increase on gastroduodenal flow per volume of infused saline equivalent to 0.5% of body weight, P < 0.001), lasted for at least 90 minutes after infusion was completed and was also obtained by expanding previously bled animals. Hypovolaemia due to bleeding was followed by an increase on gastroduodenal flow of about 88% above control values (P < 0.05) when haemorrhage was equal to 3% of body weight. This effect was also volume dependent (23 % increase on gastroduodenal flow per volume of blood shed equivalent to a 0.5% of body weight, P < 0.01) and was reversed after blood volume was restored. These modifications in the resistance of the gastroduodenal segment to the flow of liquid due to acute volaemic changes suggest that the extracellular fluid volume modulates the contractile activity of the gastroduodenal portion of the gut possibly to set a gastroduodenal handling of liquid adequate to cope with volaemic imbalances.