Effects of salvianolic acid B on neurons during oxygen/glucose deprivation and reintroduction

AIM: To observe the damage induced in the primary cultured rat cortical neurons by oxygen/glucose deprivation and reintroduction, and to investigate the neuroprotective mechanism of salvianolic acid B (SalB). METHODS: Primary cultured rat cortical neurons were randomly divided into the control group, the model group and the SalB group. The cell model was established by oxygen/glucose deprivation for 3 h followed oxygen/glucose reintroduction for 24 h. The cortical neurons viability was determined by MTT assay. The leakage rate of lactate dehydrogenase (LDH) was measured by chromatometry. The mitochondrial membrane potentials (MMP) and the apoptosis rate were quantitatively analyzed by flow cytometry. The cytosolic free calcium was assessed using LSCM. The morphologic changes of neuronal nuclei were observed by Hoechst 33342 fluorescence staining. RESULTS: Compared to the model group, the cortical neurons viability, the survival rate and the fluorescence value of MMP in the SalB group were obviously increased (P<0.05,P<0.01). In addition, in the SalB group, the leakage rate of LDH, the fluorescence intensity of cytosolic free calcium and the apoptosis rate were significantly lower than those in the model group (P<0.01). CONCLUSION: The neuroprotective mechanism of SalB in the oxygen/glucose deprivation and reintroduction neurons would be due to the fact that SalB maintains the MMP and the calcium homeostasis.     

网络时代高校图书馆读者服务工作的创新

文章分析了网络环境下读者服务工作的特点,进而探讨了网络环境下创新读者服务工作的问题。     

环保垃圾车刮板有限元分析及轻量化设计

刮板是环保垃圾车收集垃圾的主要工作部件。本文建立了刮板的三维模型和有限元模型,获得了最大载荷作用下各部位的应力应变的分布,并根据有限元模型计算了模态频率和模态振型,最后采用灵敏度分析方法对刮板结构做了轻量化设计。改进后的方案已经应用于实际生产,降低了材料成本。     

汽车悬架阻尼匹配研究及减振器设计

为了使车辆满足平顺性要求,对车辆悬架系统阻尼匹配进行了研究,建立了最佳阻尼比设计方法及减振器速度特性分段线性数学模型.以此模型为基础,建立了减振器阎系参数设计数学模型,并对阀系参数进行优化设计.对设计减振器进行了特性试验和整车振动试验,并与原车裁减振器性能进行了对比.结果表明,车辆悬架系统阻尼匹配合理,减振器阀系参数设计方法正确,设计参数值准确、可靠.     

几种海藻中溴过氧化物酶的筛选及酶学性质

溴过氧化物酶(BrPOD)是具有特殊功能的过氧化物酶,海藻是其主要来源。对几种中国海域的红藻如角叉菜(Chondrus ocellatus)、龙须菜(Gracilaria sjoestedtii)、珊瑚藻(Corallina officinalis)进行了溴过氧化物酶的藻种筛选,并对酶活较高的珊瑚藻进行溴过氧化物酶分离纯化及性质的研究。通过硫酸铵沉淀、DEAE-cellulose 52离子交换层析、Sephadex G-100凝胶层析等方法,从珊瑚藻中分离得到溴过氧化物酶。对该酶性质研究表明,该酶分子量较大,表观分子量为64 kD;溴化单氯甲酮的最适pH值为6.0;pH在5.0-9.0时酶活性稳定;在30-70℃温度范围内酶活性稳定;Ca2 、Co2 、Cu2 、Mn2 、NaF和EDTA等化合物使溴过氧化物酶活性下降,钒酸盐能提高酶活性。反应动力学实验表明,该酶对Br-、H2O2的Km分别为7.40 mmol/L和96.09μmol/L。     

日粮中不同糖肽酮萜素水平对肉鸡生长性能的影响

选1日龄Avian肉仔鸡800羽,随机分成4组(每组4个重复,每个重复50羽)进行饲养试验。对照组喂基础日粮(无任何添加剂),各处理组饲粮在基础饲粮中0.25、0.5、0.75g/kg糖肽酮萜素。试验期为49d。试验结果表明:无论对于肉仔公鸡还是母鸡,无论在哪个生长阶段,各试验组的日增重均比对照组有显著提高,料肉比均显著降低。其中以0.5g/kg糖肽酮萜素添加水平促生长效果最好。     

浙江沿海细菌芳香族氨基酸代谢途径的研究

根据苯丙氨酸脱氨酶可由苯丙氨酸诱导产生的原理,采用以苯丙氨酸为底物的简易纸片法为初筛模型,筛选浙江沿海具有产苯丙氨酸酶能力的细菌。对2 315株海洋细菌发酵液的研究结果表明,23.20%的细菌可以产生苯丙氨酸脱氨酶,其中12.22%具有微弱酶活力,8.68%具有较低酶活,2.07%具有中等酶活,0.23%具有强酶活。在浙江沿海有76.80%的细菌通过将苯丙氨酸羧化转变成酪氨酸后进入三羧酸循环,进而参与机体代谢;其余细菌可以通过PAL的作用来转移苯丙氨酸的氨基形成苯丙酮酸和氨。     

高职院校应用写作教学摭谈

本文从高职院校应用文的教学观念、教材、教学手段、教学方法等几个方面对目前高职语文教学存在的弊端进行分析,并提出相应的改革办法和措施,希望能对高职语文教学改革有所帮助。     

生态旅游景区注意力管理的探讨

介绍了国内外对"注意力"、"注意力管理"研究的现状.论述了注意力管理在生态旅游景区中应用的重要意义.生态旅游景区的注意力管理包涵经营者的注意力管理,对环境保护的注意力管理、员工的注意力管理、生态旅游者的注意力管理、当地居民的注意力管理等.     

Effects of Dietary Binders on Survival and Growth Performance of Postlarval Tongue Sole, Cynoglossus semilaevis (Günther)

A 30‐d feeding experiment was conducted in tanks to investigate the effects of four different binders (2% in microdiet) on the survival, growth performance, and specific activity of digestive enzymes in tongue sole, Cynoglossus semilaevis Günther, postlarvae (24 d after hatching, with initial average wet weight of 22.4 ± 6.65 mg [mean ± SD]). Five approximately isonitrogenous and isoenergetic microbound diets were formulated with carrageenan (Car), sodium carboxymethylcellulose (CMS), sodium alginate (SA), and gelatin (Gel) as binders, and a diet with no special binder as a control. A commercial diet (RQ Com., manufactured by Marubeni Nisshin Feed Co., Ltd., Chita, Japan) was used as another tested diet, and Artemia nauplii was used as live prey control. The results showed that the survival of the fish fed SA diet (31.3%) was significantly higher than that of fish fed CMS (21.8%), Car (10.8%), and control (21.8%) diets (P < 0.05), but significantly lower than that of the fish fed the live prey (54.5%) diet (P < 0.05). The results of growth followed the similar pattern as that of survival, although there were no significant differences in specific growth rate (SGR) among fish fed SA, CMS, Gel, the control, and RQ diets (7.2, 6.8, 7.0, 6.9, and 7.3% per day; P > 0.05). However, fish fed Car diet had a significantly lower SGR (5.9% per day) than fish fed other diets. Percentages of secreted amylase in fish fed artificial diets were not significantly different, but fish fed artificial diets had significantly higher (P < 0.05) secreted amylase than live prey group. Percentage of secreted trypsin in fish fed SA diet (54.9%) was relatively higher compared with other binders, and not significantly different from RQ Com. and live prey treatments. However, trypsin in fish fed Car diets (29.3%) was significantly lower than in other groups. Specific activities of alkaline phosphatase (AP) in the intestine and AP and leucine aminopeptidase N in brush border membranes in fish fed SA diet (264.6, 1882.8, and 187.2 mU/mg protein) were relatively higher compared with other binders. These results indicate that SA is one of suitable binders compared with carrageenan, CMS, and gelatin in microdiet of postlarval tongue sole.