铜离子对绿色微囊藻增殖的影响

通过藻类增长潜力（AGP）实验,研究了不同浓度铜离子对绿色微囊藻（Microcystis viridis）增殖的影响。结果显示,低浓度的Cu^2＋（0．001～0．1mg／L）对绿色微囊藻的增殖有促进作用,高浓度的Cu^2＋（〉1mg／L）降低了藻细胞密度、叶绿素a以及微囊藻毒素的含量,抑制了绿色微裳藻的增殖。     

加替沙星-壳聚糖纳米粒胶联羊膜药膜的制备及体外实验研究

目的制备一种新型生物多功能复合材料——加替沙星．壳聚糖纳米粒胶联羊膜药膜,并观察其体外缓释性能及抑菌作用。方法采用离子胶联法制备加替沙星－壳聚糖纳米粒并检测其表征,然后将栽药纳米粒加入到纤维蛋白胶中,混匀后再与羊膜胶联制成加替沙星－壳聚糖纳米粒胶联羊膜药膜,光镜及扫描电镜下观察其形态学特征,高效液相色谱法测定其中加替沙星的浓度,微量肉汤稀释法检测其体外抑菌活性。结果加替沙星纳米粒的粒径为291±33nm,载药量为10．46％,包封率为61．32％。载有纳米药物的纤维蛋白胶与羊膜基底面粘合紧密,呈圆形的加替沙星纳米粒附着在胶原纤维的网状结构上。在体外,加替沙星－壳聚糖纳米粒胶联羊膜药膜可持续释药达15天,对金黄色葡萄球菌和铜绿假单胞菌的最低抑菌浓度分别为0．05μg／ml和0．42μg／ml。结论加替沙星－壳聚糖纳米粒胶联羊膜药膜在体外具有良好的缓释性能及抑茵作用。     

草石蚕水苏糖检测技术的研究

建立了我国传统植物草石蚕块茎中水苏糖的定性分析和定量检测方法。采用薄层层析（TLC）法定性分析,选择乙酸乙酯／甲醇／水／冰醋酸（3／2／1／2）为展开剂,采用二苯胺-苯胺一磷酸为显色剂。该条件下水苏糖Rf值为0．47,显色点为棕黄色,斑点清晰,与其他糖分分离良好。用高效液相色谱-示差折光检测（HPLC—RID）法定量检测,采用Kromasil NH2柱,流动相为乙腈／水（55／45,v／v）,柱温为30℃,流速为1．0mL／min,进样体积10μL,该色谱条件下,水苏糖峰出峰对称性好,时间较短（9．5min）,水苏糖浓度在1．0～8．0mg／mL范围内线性关系良好（R2=0．9996）,回收率在96．O％～102．5％之间。在生产应用中,可以根据实际采用其中一种或者两种方法结合,以满足检测需要。     

测定肿瘤细胞内外5-氟尿嘧啶含量的方法研究

目的建立了高效液相色谱法测定A549组胞内外5-氟尿嘧啶含量的方法,为探索5-氟尿嘧啶的作用机理奠定基础。方法色谱柱采用Hypersil ODS柱（4．6mm×250mm,5μm）;流动相为甲醇·水=2：98（V／V）;流速：0．8ml／min;柱温：30℃;检测波长：265nm;进样量为5μl。结果细胞内液中5-氟尿嘧啶在0.1～50．0μg/ml范围内线性关系良好（r=0．9996）,平均回收率为97．65％,RSD为0．40％,日内和日间精密度分别为1．30％,1．04％;细胞跨液中5-氟尿嘧啶在1．0～250．0μg/ml范围内线性关系良好（r=0.9999）,平均回收率为102.34％,RSD为2．11％,日内和日间精密度分别为1．32％,1．06％。结论该色谱方法简便易行,准确度高,重现性好,可用于细胞内外5-氟尿嘧啶浓度的动态变化规律研究。     

齐墩果酸抑制肝癌细胞QGY增殖和诱导凋亡的作用研究

目的研究齐墩果酸对人肝癌细胞QGY增殖的作用及与细胞内钙离子浓度（[Ca2＋]i）关系。方法将浓度分别为40、80、100μg／ml齐墩果酸作用肝癌H细胞QGY24h后,DAPI染色,以荧光显微镜观察细胞形态变化;以11组不同浓度齐墩果酸（5—400μg／ml）作用QGY细胞24h后,用四甲基偶氮唑蓝（Myr）法检测QGY增殖情况;分别以不同浓度齐墩果酸（80、100、120μg／ml）作用QGY细胞24h后,流式细胞仪检测细胞周期改变、细胞凋亡率和[Ca2＋]i。结果细胞增殖被抑制并发生凋亡：不同浓度齐墩果酸能够抑制QGY细胞株增殖,且在5—120μg／mL范围内呈剂量依赖性,药物作用细胞24h、48的Ic50分别为76．27μg／mL和66．56μg／mL;处理组细胞周期在s期产生阻滞、细胞内[Ca2＋]i较对照组显著增加,细胞凋亡率和[Ca2＋]i与药物浓度存依赖关系。结论齐墩果酸能够抑制肝癌细胞QGY增殖和诱导其凋亡;诱导凋亡可能与细胞内[Ca2＋]i增加有关。     

无溶剂微波辅助-液相微萃取测定土壤中的滴滴涕

建立了一种快速、有效、环境友好的样品前处理方法,即无溶剂微波辅助-液相微萃取技术,并结合高效液相色谱法对土壤中的滴滴涕残留进行了测定分析,同时对影响萃取效率的相关因素,如萃取溶剂的种类、微波辐射功率、萃取时间和pH等因素进行了优化。最终确定最佳优化条件为：萃取溶剂为正庚烷,微波辐射功率为120w,萃取时间为1rain,pH为5。在最优条件下,滴滴涕的检出限（S／N=3）为0．18μg／kg,定量限（S／N=10）为0．59μg／kg,实际土壤加标回收率87．34％～96．41％之间,相对标准偏差RSDs在5．75％～6．72％之间。理论分析和实验结果表明,该方法具有操作简便,节省溶剂,快速,高效,选择性好等特点。     

外源性H2S通过调节β-位淀粉样前体蛋白裂解酶1表达对PC12细胞APP／Aβ代谢的影响

目的观察外源性硫化氢对嗜铬细胞瘤细胞β-位淀粉样前体蛋白裂解酶1（BACE1）的调节作用,进而探讨其对淀粉样前体蛋白／β-位淀粉样蛋白代谢途径的影响。方法用硫氢化钠作外源性H2s供体,实验设空白对照组、NaHs50μmol／L组、NaHS100μmol／L组和NariS200μmol／L组,按分组浓度处理PC12细胞24h后,RT-PCR和Western blot法检测细胞内BACE1 mRNA及蛋白表达,并用Western blot法继而检测APP代谢过程中关键蛋白APP、C99、C83表达变化,EusA法检测细胞培养液中AB40和AB42水平。结果NaHS在实验浓度范围内从基因与蛋白两个水平上呈剂量依赖性下调BACE1表达,并下调C99、Ap40和Ap42蛋白表达,上调C83蛋白,各NaHS组分别与对照组比较,差别均有统计学意义（P〈0．05）,而对APP蛋白表达没有影响,各组间比较差别无显著性（P〉0．05）。结论外源性H2s具有通过调节PC12细胞BACE1表达下调APP／Aβ代谢的作用。     

水蒸气抑制熄灭杯式燃烧器扩散火焰的机理

在自行研制的杯式燃烧器的基础上，采用实验与数值模拟相结合的方法对水蒸气抑制熄灭甲烷／空气扩散火焰的过程进行了研究，分析火焰抑制熄灭现象产生的过程与作用机理，得到了临界灭火浓度与协流氧化剂流量的变化规律．结果表明，水蒸气抑制熄灭杯式燃烧器扩散火焰是典型的局部火焰熄灭机理．随着水蒸气浓度的增加，杯式燃烧器扩散火焰的根部首先向内收缩并悬举至新的稳定高度，当根部反应核的燃烧速率随着火焰温度下降受到极大抑制后，火焰根部的预混区将因更多水蒸气的扩散稀释作用而无法继续维持火焰向外的振荡传播过程，火焰会脱离燃烧杯面而熄灭．破坏火焰根部核心燃烧区的反应条件是熄灭扩散火焰的关键．水蒸气临界灭火浓度在一定的氧化剂流量范围内不依赖于空气流量，在临界灭火浓度曲线上存在一“平缓区”．实验测得的临界灭火质量百分比浓度分别为水蒸气（16．7±0．6）％、二氧化碳（15．9±0．6）％、氮气（31．9±0．6）％，与数值模拟结果合理吻合．     

香烟烟雾提取物对人内皮细胞细胞色素C氧化酶活性及细胞凋亡的影响

目的探讨香烟烟雾提取物（cigarette smoking extract,CSE）对内皮细胞细胞色素C氧化酶（cytochmme Coxidase,COX）活性及凋亡的影响。方法体外培养ECV304,分别给予0％、0．5％、1％、5％CSE刺激12h,及5％CSE刺激0h、6h、12h、24h后,生化法检测COX活性;投射电镜和流式细胞仪观察细胞凋亡情况。结果CSE引起COX活性下降,且随着刺激浓度和时间的增加而下降（P〈0．05）;电镜示CSE干预组细胞出现明显的凋亡形态学改变;流式细胞仪结果示不同浓度CSE分别作用12h后凋亡率依次增高,除O％CSE组和0．5％CSE组间比较无统计学意义（P〉0．05）,余各组间比较均有统计学意义（P〈0．05）;5％CSE作用不同时间后,随着干预时间的延长细胞凋亡率逐渐升高（P〈0．05）。结论CSE抑制内皮细胞COX活性,呈浓度和时间依赖性;CSE诱导内皮细胞凋亡,呈浓度和时间依赖性;COX活性的下降可能在CSE所致的内皮细胞凋亡中具有重要作用。     

Sn/In/Ti纳米复合氧化物对可燃和有毒气体敏感特性研究

采用可控溶胶-共沉淀法合成了二元Sn／In和三元Sn／In／Ti纳米复合氧化物作为半导体CO，NO2和CH4传感器的敏感材料．通过优化可控制备参数研制出化学均一、高热稳定的纳米晶体复合氧化物．利用各种分析方法表征了纳米粉体的物性和结构，并对CO，CH4和NO2的气敏特性进行了考察．实验结果表明，所研制的二元纳米气敏材料对CO有高灵敏度和选择性，引入适量TiO2提高了对CH4的灵敏度和选择性，经少量金属元素掺杂和氧化物添加后气敏性质有大幅度提高．研究了复合物组成，先驱物焙烧温度及气敏操作温度和待测气体浓度对灵敏度的影响．其优化条件为金属盐总浓度0．05mol／L，金属阳离子比Sn^4＋：In^3＋为40％（摩尔分数）的纳米复合物在600℃时焙烧6h，则在150℃～250℃之间对CO和NO2有较高灵敏度，在气敏条件下以程序升温吸脱附实验研究了复合物表面的吸脱附行为，X射线光电子能谱分析证实复合物组分间存在着电子和化学的协同效应，气敏机理为表面吸附控制型．     

铜合金三酸抛光微观效果研究

通过扫描电子显微镜微观观察的方法对三酸化学抛光液中各组分对铜合金表面抛光效果的影响进行了研究.结果表明,采用微观观察法能够更直观有效地研究各组分对铜合金表面抛光效果的影响,在此基础上,获得铜合金表面最佳抛光液:磷酸200~300ml/L、硫酸200~400ml/L(磷酸+硫酸500~600ml/L)、硝酸200~250ml/L(紫铜)、40~150ml/L(黄铜)、盐酸5~15ml/L.经处理的铜合金表面不仅外观光亮、微观平整,而且铜合金表面制备的转化膜中性盐雾测试时间更长、防腐性能更好.根据扫描电子显微镜观察铜合金微观形貌获得最佳抛光液组成的方法,简单方便、准确有效     

'Amicus Plato sed…': Fowler's New Mathematical Reconstruction of the Mathematics of Plato's Academy

A study of the metallurgy and manufacturing techniques of a group of eight astrolabes (seven from Lahore, one attributed to India) using non-destructive methods has produced the earliest evidence for systematic use of high-zinc (α?+?β) brass. To produce this alloy, the brass industry supplying the Lahore instrument makers must have co-melted metallic copper and zinc. This brass-making technology was previously believed to have been developed on an industrial scale in the nineteenth century in Europe. This work hypothesizes that this technology was used in Lahore on an industrial scale as early as ad 1601. In addition, this work hypothesizes that the α?+?β brass alloy was used specifically for its ease in manufacturing the thin sheet brass required for astrolabe-component manufacture.     

Local adjuvants: the influence of sodium dodecylbenzene sulphonate on immunization with aerosolized antigen.

Guinea-pig respiratory and serum antibody responses were enhanced following exposure to aerosols of bovine IgG2 dissolved in solutions of sodium dodecylbenzene sulphate (SDBS). Enhanced response was seen in both primary and secondary immunization. Cell-mediated immune response (indirect macrophage migration influencing test) was not altered by SDBS. Results are discussed with a view to the possible utility of SDBS as adjuvant for prophylactic immunization.     

Local adjuvants: The influence of sodium dodecylbenzene sulphonate on immunization with aerosolized antigen

Summary Guinea-pig respiratory and serum antibody responses were enhanced following exposure to aerosols of bovine IgG₂ dissolved in solutions of sodium dodecylbenzene sulphate (SDBS). Enhanced response was seen in both primary and secondary immunization. Cell-mediated immune response (indirect macrophage migration influencing test) was not altered by SDBS. Results are discussed with a view to the possible utility of SDBS as adjuvant for prophylactic immunization.Acknowledgment. This research was supported by a grant from the Ontario Ministry of Health. The technical assistance of Ms Judy Little is gratefully acknowledged.     

Leishmania donovani in hamsters: stimulation of non-specific resistance by some novel glycopeptides and impact on therapeutic efficacy

Several glycopeptides structurally related to muramyl dipeptide (MDP) have been synthesized and evaluated for their ability to stimulate the non-specific resistance of hamsters against L. donovani infection. These compounds have been named CDRI compounds. The synthetic procedure used for compounds 86/448 and 84/212 is described. MDP and its synthetic congeners were administered as immunostimulants at a prophylactic dose of 3 mg/kg at two weeks interval. The challenge infection (1 x 10(7) amastigotes i.c./hamster) was given in between two doses of the compounds. One of the glycopeptides, CDRI comp. 86/448, has been found to be significantly more potent than MDP, effecting 92% inhibition of the challenge dose, whereas MDP produced only 26.5% inhibition. The effect of comp. 86/448 lasted until day 7 of challenge. The efficacy of sodium stibogluconate was appreciably improved in hamsters treated with comp. 86/448.     

The effect of actinomycin D on the production of viruses by the protoplasts of Chinese cabbage infected in vitro by the yellow mosaic virus of turnips]

Chinese Cabbage (Brassica sinensis L. var. Cantonner) protoplasts were infected by Turnip yellow mosaic virus (TYMV) and inoculated in the presence or absence of actinomycin D. Virus production was determined 40 hrs. after inoculation, the time required for the virus replication cycle to be terminated. While actinomycin D had no effect on TYMV production when present at a concentration of 1 microng/ml, a 50 to 80% inhibition of virus production was noticed at concentrations of the order of 5 to 10 microng/ml, and the inhibition reached 90% with 25 microng/ml.     

Leishmania donovani in hamsters: Stimulation of non-specific resistance by some novel glycopeptides and impact on therapeutic efficacy

Summary Several glycopeptides structurally related to muramyl dipeptide (MDP) have been synthesized and evaluated for their ability to stimulate the non-specific resistance of hamsters againstL. donovani infection. These compounds have been named CDRI compounds. The synthetic procedure used for compounds 86/448 and 84/212 is described.MDP and its synthetic congeners were administered as immunostimulants at a prophylactic dose of 3 mg/kg at two weeks interval. The challenge infection (1×10⁷ amastigotes i.c./hamster) was given in between two doses of the compounds. One of the glycopeptides, CDRI comp. 86/448, has been found to be significantly more potent than MDP, effecting 92% inhibition of the challenge dose, whereas MDP produced only 26.5% inhibition. The effect of comp. 86/448 lasted until day 7 of challenge. The efficacy of sodium stibogluconate was appreciably improved in hamsters treated with comp. 86/448.     

Liver ferritin synthesis following chronic alcohol administration to rats: Modulation by propylthiouracil

Summary Liver ferritin synthesis was inhibited by 22.3% in rats treated with alcohol (2 g/kg) for 45 days. This inhibition was prevented by simultaneous administration (5 mg/kg) of propylthiouracil during the last 15 days. There was no significant effect on liver ferritin concentration.     

Microbial corrosion of concrete

Summary Sulphuric-acid-producing thiobacilli cause severe corrosion of concrete walls in sewage pipelines. The bacteria excrete sulphuric acid, which degrades carbonaceous binding material. Nitrifying organisms have been found in high cell numbers on historical sandstone buildings as well as on concrete buildings. The nitric acid, which is excreted by these organisms as metabolic end-product, also causes severe corrosion. The microorganisms are able to metabolize inorganic substances like ammonia and NO originating from air pollution.The natural process was remodelled by means of simulation experiments. It became evident that mineral-acid-producing bacteria play an important role in biodeterioration of building materials.     

Physicochemical properties of an extracellular polysaccharide isolated from culture media of Bacillus amyloliquefaciens]

A new extracellular polysaccharide has been isolated by chromatography on anion exchanger of a fraction obtained from highly viscous culture media of Bacillus amyloliquefaciens. This polysaccharide is characterised by high molecular weight (1,000,000 dalton) and intrinsic viscosity (323 ml/g). It contains 24% neutral sugar (galactose and mannose 5:1), 35% glucuronic acid and 51.5% N-acetylhexosamines (N-actylglucosamine, N-acetylgalactosamine and N-acetylbacillosamine 6:9:1).