基于大脑情感学习的转台逆模型补偿控制

针对传统控制方法难以克服飞行仿真转台伺服系统中存在的摩擦等非线性干扰力矩问题,提出了一种基于大脑情感学习(brain emotional learning, BEL)模型的转台伺服系统复合控制方法. 在传统PI反馈控制器的基础上,设计了基于BEL模型的同结构系统逆模型辨识器和前馈补偿控制器. 通过在线辨识系统逆模型来学习BEL模型的节点权值. 理想转台模型的数值仿真和实际转台伺服系统的实验结果都表明：BEL模型学习能力强,能满足实时控制要求,基于BEL模型的复合控制策略能有效抑制摩擦力矩的影响,提高转台系统的跟踪性能.     

高压氧疗对脑损伤治疗作用机制的研究进展

脑损伤可引起脑组织的缺血缺氧。脑供血减少,会引起脑缺氧,但脑缺氧也可单独发生。若脑组织缺血缺氧的状态得不到及时纠正,氧参与的细胞内物质能量代谢将发生异常,如生成ATP的三羧酸循环、离子的转运等基本的生命活动都将受到影响,甚至停止。而蛋白质、核酸、脂质等物质的运输及代谢也将受到影响。这种状况持续数分钟,大脑的生理功能将受到影响,时间愈久这种变化愈难逆转。近年来,有研究表明,高压氧疗(HBOT)能改善损伤引起的脑组织缺血缺氧的状态,并对损伤的脑组织有修复的作用。其可能的途径如下:HBOT通过减少内皮素的生成,改善损伤后的脑血管痉挛状态、平衡脑血流以及降低升高的颅内压等,改善脑组织的缺血缺氧状态;并能通过改变MBP、caspases基因家族、Bcl-2/Bcl-xL以及TSPO、Nogo-A及其受体Ng-R等的表达,起到保护受损脑细胞、减少脑细胞凋亡以及促进神经细胞再生的作用;HBOT还可能通过增加胎盘生长因子(PLGF)的生成,起到促进血管生成及损伤脑组织再生的作用;此外,HBOT还能引起受损脑组织内多种炎症因子的改变,这也在一定程度上影响着脑损伤的预后。HBOT引起多种分子表达的改变,起到对损伤脑组织的修复作用...     

缺氧后小鼠脑匀浆提取液对儿童MSCs分化为神经细胞的影响

目的:观察缺氧后不同时段小鼠脑匀浆提取液对儿童骨髓间充质干细胞(MSCs)分化为神经元样细胞的影响,为筛选MSCs的最佳移植时间提供依据.方法:制作缺氧小鼠模型;并制取缺氧不同时间段脑匀浆提取液;诱导儿童MSCs;比较MSCs分化为神经元样细胞的阳性率.结果:缺氧后1、4,7、10、13 d小鼠脑匀浆提取液均可将MSCs诱导成神经元样细胞,经免疫学鉴定NES染色强阳性;但各组阳性率不同,以缺氧10 d后阳性率(21.02±3.38)%最高,与其他各组比较有统计学差异(P<0.05).结论:缺氧后小鼠脑匀浆提取液可诱导儿童MSCs分化为神经元样细胞,缺氧后10 d的分化率最高.     

Effect of Salvianolic Acid B on Mitochondrial Function of CerebralIschemia in Mice

The effects of salvianolic acid B (SalB) on the mitochondrial membrane potential (MMP), calcium, and apoptosis of neurons with cerebral ischemia in mice were investigated using an acute cerebral ischemia model established by ligating the bilateral common carotid arteries in mice. The MMP, the intracellular calcium concentration, and the apoptosis rate of cortical neurons were measured at 6 min, 12 min, 18 min, 24 min, and 30 min after cerebral ischemia by a flow cytometer. The experiments show that SalB increases the MMP and reduces the intracellular calcium and the apoptosis rate at different stages of the cerebral ischemia in mice. The results show that the protective mechanism of SalB on cerebral ischemia enhances the MMP and maintains intracellular calcium homeostasis.     

导游队伍质量滑坡诱因分析与对策研究

旅游业是中国经济发展的支柱产业之一,目前高级别导游人才缺乏和导游人才流失现象严重。通过分析导致导游人员流失的主要因素,对解决导游人才流失问题进行探讨,提出一些解决问题的办法。     

Localization of the brain calculation function area with MRI

The aim of this study is to define the anatomical localization of corresponding brain function area during calculating. The activating modes in brain during continuous silent calculating subtraction and repeated silent reading multiplication table were compared and investigated. Fourteen volunteers of right-handedness were enrolled in this experiment. The quite difference of reaction modes in brain area during the two modes of calculation reveal that there are different processing pathways in brain during these two operating actions. During continuous silent calculating, the function area is localized on the posterior portion of superior and middle gyrus of frontal lobe and the lobule of posterior parietal lobe (P < 0.01,T = 5.41). It demonstrates that these function areas play an important role in the performance of calculation and working memory. Whereas the activating of visual cortex shows that even in mental arithmetic processing the brain action is having the aid of vision and visual space association.     

血脑屏障对钙调神经磷酸酶B亚基及其降解肽段阻碍作用的研究

应用1,3,4,6－四氯－3α,6α二苯基苷尿（Iodogen)法对钙调神经磷酸酶B亚基进行1125I标记,获得了比活度为740MBq.mg^-1,放化纯度为95．7％的125I标记的钙调神经磷酸酶B亚基,标记率高达85％,利用该标记物研究血脑屏障对其进入脑的阻碍作用,结果显示血脑屏蔽能够阻止完整的钙调神经磷酸酶B亚进入脑,但是它的降解肽段能够透过血脑屏障进入脑组织。     

13～18岁青少年脑电α波的发展特点

以192名13－18岁青少年为研究对象,采用脑电波超慢涨落分析技术（ET）,对其12导联脑电图（EEG）进行了记录和分析,重点探讨了α波 (8-13Hz）的发展特点。结果表明：1）随年龄的增长,13－18岁青少年α波不同频率成分的变化幅度不大;2）平均频率f^-的年龄变化不明显,基本保持在10Hz左右,但女性的高于男性;3）青少年α波的优势成分不随年龄变化而变化,13－18岁的主导成分均为10Hz的α波;4）不同频率的α波在各脑区的分布均存在显著差异（P＜0．05）,α波的f^-的分布特点为从额叶到枕叶逐渐增大;5）不同频率脑电的α波的比率R的分布表现出不同的左右不对称性,α波的f^-表现出明显的左脑优势。     

大鼠脑损伤后海马GAP-43 mRNA水平的变化

以DIG（Digoxigenin）标记的GAP-43 cDNA片段为探针,使用原位杂交方法,检测了大鼠皮层硬性脑挫伤后GAP-43 mRNA水平的变化。结果表明：海马CA3、CA1和DG区的GAP-43 mRNA水平在损伤后48h明显升高,其中CA3区变化最甚,而且伤侧比对侧显著。1周和2周后表达仍维持较高水平,但不如48h的高,这显示表达的峰值在1周之内。上述结果为研究脑损伤后生理及机能代偿的修复机制提供了有意义的信息。     

Alternative exon usage selectively determines both tissue distribution and subcellular localization of the acyl-CoA thioesterase 7 gene products

Acyl-CoA thioesterases (ACOTs) catalyze the hydrolysis of acyl-CoAs to free fatty acids and coenzyme A. Recent studies have demonstrated that one gene named Acot7, reported to be mainly expressed in brain and testis, is transcribed in several different isoforms by alternative usage of first exons. Strongly decreased levels of ACOT7 activity and protein in both mitochondria and cytosol was reported in patients diagnosed with fatty acid oxidation defects, linking ACOT7 function to regulation of fatty acid oxidation in other tissues. In this study, we have identified five possible first exons in mouse Acot7 (Acot7a–e) and show that all five first exons are transcribed in a tissue-specific manner. Taken together, these data show that the Acot7 gene is expressed as multiple isoforms in a tissue-specific manner, and that expression in tissues other than brain and testis is likely to play important roles in fatty acid metabolism. Received 5 February 2007: received after revision 3 April 2007; accepted 19 April 2007