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991.
To deeply understand the adsorption process of oxygen on the surface of a plutonium gallium system and to reveal the chemical reaction mechanism at the initial stage of oxidative corrosion on the surface of plutonium gallium alloy at a theoretical level, the adsorption behavior of oxygen molecules on the surface of a plutonium gallium system was investigated by a first-principles approach based on density flooding theory. The results show that the molecular bond length increases and finally breaks when the surface oxygen molecule is adsorbed on the surface of plutonium gallium system and dissociates into two atomic states. The most likely adsorption position of oxygen molecules on the surface of plutonium gallium system is hole-site vertical adsorption with the adsorption energy size of 10.7 eV. The bonding between oxygen atom and surface is mainly due to the overlapping hybridization of Pu-6s, Pu-7s, Pu-6d, Ga-3d and O-2p orbitals. Oxygen molecules mainly interact with the atoms of the first layer on the surface of the plutonium gallium system. The oxygen atoms after stable adsorption are able to diffuse to the subsurface of the plutonium gallium system after overcoming the energy barrier of 16.7 eV and form a stable structure. The research results reveal the initial reaction process and adsorption law of oxygen on the surface of plutonium gallium system from microscopic level, which is helpful to further explore the surface corrosion prevention technology of plutonium gallium system and improve the reliability and safety of plutonium gallium alloy components.  相似文献   
992.
Porcine circovirus-like virus (PCLV) is a member of circovirus that contains a single-strand DNA genome, which may be one of the pathogens that causes diarrheal symptoms in pigs. The Rep protein encoded by the genome of PCLV may be responsible for viral genome replication. The development of serological detection methods for PCLV is of great necessity for clinical diagnosis, as well as epidemiological investigations. Therefore, this study attempted to build an indirect enzyme-linked immunosorbent assay (ELISA) to examine antibodies against PCLV based on the His-tagged recombinant Rep protein. Full-length PCLV Rep protein was induced and expressed in E. coli and was purified as an antigen to establish an ELISA detection kit. The purified Rep protein was used to inject into mice to produce specific antibodies. There was no cross-reaction of Rep-based ELISA with antisera against other porcine viruses. The intra-assay and inter-assay coefficient variations (CVs) were 0.644–8.211% and 0.859–7.246%, respectively, indicating good repeatability. The non-cross-reaction with TGEV, PRRSV and PCV2 testing showed high sensitivity and high specificity for this ELISA assay. A total of 1593 serum samples collected from different pig farms in Jiangxi Province were tested for anti-PCLV Rep antibodies, and 284 (17.83%) of the 1593 samples were Rep antibody positive. Altogether, the indirect ELISA detection tool developed in this study could be applied to examine serum of PCLV antibodies with good repeatability, high sensitivity and high specificity. In addition, field sample detection results suggested that the PCLV antibody has a low prevalence in pig populations in Jiangxi Province of China.  相似文献   
993.
目的:分析体外循环胸腔镜配合纤维软镜心脏手术常出现的危险因素。方法选择心、肺功能良好的杂种犬40只,随机分为实验组(20只,房间隔和室间隔缺损各10只)和对照组(20只,房间隔和室间隔缺损各10只)。实验组进行胸腔镜配合纤维软镜体外循环下同时模拟房间隔和室间隔缺损修补术、右室流出道疏通术。对照组进行胸腔镜体外循环下房间隔和室间隔缺损修补术、右室流出道疏通术。分别记录两组动物手术前后平均动脉压、中心静脉压、心率等,以及术中上下腔静脉套带时间、手术时间、体外循环时间、主动脉阻闭时间和转机时间等。观察手术并发症发生情况。结果术后实验组动物平均动脉压、中心静脉压、心率等均明显优于对照组,差异均有统计学意义(P<0.05);术中实验组动物上下腔静脉套带时间、手术时间、体外循环时间、主动脉阻闭时间、转机时间等也均明显优于对照组,差异均有统计学意义(P<0.05)。结论胸腔镜配合纤维软镜体外循环下同时模拟房间隔和室间隔缺损修补术、右室流出道疏通术可获得良好的临床效果,适合在临床广泛应用。  相似文献   
994.
Exposure to nanosilver found in food‐ and cosmetics‐related consumer products is of public concern because of the lack of information about its safety. In this study, two widely used in vitro cell culture models, human liver HepG2 and colon Caco2 cells, and the flow cytometric micronucleus (FCMN) assay were evaluated as tools for rapid predictive screening of the potential genotoxicity of nanosilver. Recently, we reported the genotoxicity of 20 nm nanosilver using these systems. In the current study presented here, we tested the hypothesis that the nanoparticle size and cell types were critical determinants of its genotoxicity. To test this hypothesis, we used the FCMN assay to evaluate the genotoxic potential of 50 nm nanosilver of the same shape, composition, surface charge and obtained from the same commercial source using the same experimental conditions and in vitro models (HepG2 and Caco2) as previously tested for the 20 nm silver. Results of our study show that up to the concentrations tested in these cultured cell test systems, the smaller (20 nm) nanoparticle is genotoxic to both the cell types by inducing micronucleus (MN). However, the larger (50 nm) nanosilver induces MN only in HepG2 cells, but not in Caco2 cells. Also in this study, we evaluated the contribution of ionic silver to the genotoxic potential of nanosilver using silver acetate as the representative ionic silver. The MN frequencies in HepG2 and Caco2 cells exposed to the ionic silver in the concentration range tested are not statistically significant from the control values except at the top concentrations for both the cell types. Therefore, our results indicate that the ionic silver may not contribute to the MN‐forming ability of nanosilver in HepG2 and Caco2 cells. Also our results suggest that the HepG2 and Caco2 cell cultures and the FCMN assay are useful tools for rapid predictive screening of a genotoxic potential of food‐ and cosmetics‐related chemicals including nanosilver. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.  相似文献   
995.
小檗碱类衍生物的全合成及抗癌活性的研究   总被引:9,自引:0,他引:9  
本文合成了九个小檗碱类衍生物(Ⅲ_(a~g),Ⅳ,Ⅴ),其中Ⅲ_(c~g)和Ⅴ为尚未见诸文献的新化合物。Ⅲ_a只有由植物提取的报导。九个化合物经艾氏腹水癌瘤株初步筛选,说明Ⅲ_a和Ⅳ具明显抗癌活性。  相似文献   
996.
目的:研究槐耳颗粒对晚期大肠癌化疗患者中医症状及生活质量的影响。方法:将60例符合纳入标准的晚期大肠癌患者,随机分为治疗组和对照组,治疗组30例,采用槐耳颗粒联合化疗,化疗采用FOLFOX4方案;对照组30例,单纯化疗,方案同治疗组。4周期后,分别观察两组患者治疗前后中医症状评分、KPS评分,食欲及体重方面的变化。结果:两组患者在中医症状评分疗效,Kamofsky评分,食欲及体重方面比较差异有统计学意义(P〈0.05)。结论:槐耳颗粒联合化疗可改善晚期大肠癌患者的中医症候及体力状况,提高患者生活质量。  相似文献   
997.
目的:考察室温(25℃)下注射用美洛西林钠与注射用卡络磺钠在5%葡萄糖注射液中的配伍稳定性。方法:采用反相高效液相色谱法-二极管阵列检测器分别测定美洛西林钠与卡络磺钠在5%葡萄糖注射液中配伍后0~4 h内的含量及pH变化,并观察配伍液的外观变化。结果:4 h内注射用美洛西林钠与注射用卡络磺钠在5%葡萄糖注射液中配伍液外观、pH及含量均无明显变化。结论:在室温(25℃)下,注射用美洛西林钠与注射用卡络磺钠在5%葡萄糖注射液中4 h内配伍稳定。  相似文献   
998.
银杏叶中黄酮苷类化合物的研究(英文)   总被引:2,自引:0,他引:2       下载免费PDF全文
从银杏(Ginkgo biloba L.) 叶中分离得到5 个黄酮苷类化合物,通过波谱方法鉴定它们的结构为洋芹素-7-葡萄糖苷(apigenin 7-glucoside 1), 木樨草素-?¢-葡萄糖苷(luteolin ?¢- glucoside 2), 木樨草素-?¢-葡萄糖苷(luteolin ?¢- glucoside 3), 柯伊利素-7-葡萄糖苷(chrysoeriol 7-glucoside 4) 和 tricetin ?¢-methyl ether-?¢-b-D-glucoside(5)。其中化合物5 为新化合物化合物3 和4 为首次从该种植物中分得。  相似文献   
999.
青霉菌产壳聚糖酶的分离纯化及性质研究   总被引:15,自引:0,他引:15  
青霉菌(Penicilium sp.)发酵液经20%-70%硫酸铵分级沉淀,DEAE-Cellulose离子交换层析,Sephadex G-100凝胶过滤层析,得到聚丙烯酰胺凝胶电泳均一的壳聚糖酶,比活力1020u/mg,纯化182倍。其分子量为30kD,酶的最适温度和pH分别为50℃和5.0,金属离子Mg^2+和Ca^2 对酶活力有一定的促进作用,重金属离子Cu^2 、Ni^2 和Zn^2 对酶有较强的抑制作用。该壳聚糖酶具有很强的底物专一性,动力学参数Km值为2.601g/L。  相似文献   
1000.
目的:探讨冠心病(CAD)合并2型糖尿病(DM)患者血浆脂蛋白(a)[Lp(a)]水平与冠状动脉(冠脉)狭窄程度及范围之间的关系。方法:163例经冠状动脉造影(CAG)证实为CAD的2型DM患者按冠脉狭窄程度分中度(n=19)和重度(n=144)狭窄组,按病变范围分为单支(31例)、双支(48例)和多支(84例)病变组,54例无冠心病患者作为对照组,分别测量和比较各组Lp(a)、总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、载脂蛋白A-(IApoA-I)及载脂蛋白B(ApoB)水平。结果:中、重度狭窄组的Lp(a)水平高于对照组,中度狭窄组与重度狭窄组之间的Lp(a)水平差异无统计学意义。单支、双支、多支病变组Lp(a)水平高于对照组,多支病变组的Lp(a)水平高于单支、双支病变组,各组间TC、TG、HDL-C、LDL-C、ApoA-I、ApoB水平差异均无统计学意义。多元回归分析显示Lp(a)水平为冠脉狭窄程度和范围的危险因素。结论:Lp(a)水平可作为2型DM合并CAD患者冠脉病变严重性的评价指标之一。  相似文献   
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