共查询到20条相似文献，搜索用时 234 毫秒
1.
利用量子化学和分子连接性方法研究了氟喹诺酮Ｎ１位的构效关系,令人满意地解释了Ｎ１位特丁基的定量构效关系,本质原因是ＨＯＭＯ起主要作用。利用建立的ＱＳＡＲ方程,预测了Ｒ１取代基为糖基的化合物的活性,与实验结果基本一致。 相似文献
2.
茶多酚抗突变和消除自由基作用的研究 总被引：6，自引：0，他引：6
采用Ｅ．ＣｏｌｉＳＯＳ显色法，小鼠骨髓细胞微核及染色体畸变试验和体外自由基消除实验等方法测定了茶多酚复合物（ＴＰ）的抗突变和消除自由基作用．结果表明：（１）ＴＰ的终浓度在２．５和５ｍｇ／ｍｌ时，对由阳性致突变物ＭＮＮＧ，ＥＭＳ和ＮａＮ＿３诱导的ＳＯＳ应答反应均具有明显的抑制作用；（２）小鼠每日ｉｇ４０、８０和１２０ｍｇ／ｋｇ剂量的ＴＰ能明显抑制由环磷酰胺（ＣＰ）诱发的骨髓ＰＣＥ的ＭＮＣＦ，三种剂量ＴＰ的抑制率分别为４０．９８％、６６．７６％和６５．９４％；（３）ＴＰ对ＭＭＣ诱发的骨髓细胞染色体畸变（ＣＡ）的抑制率分别为６２．５６％、５５．７１％和４７．９５％；（４）在Ｘ／ＸＯ－ＥＳＲ、Ｘ／ＸＯ／Ｌｕｍｉｎｏｌ－ＢＣＬ和ＩＲ／ＮＢＴ－ＳＰＭ三种模型中ＴＰ对超氧阴离子Ｏ＿２自由基均具有极强的消除作用，消除率分别为９８±６％、９８±１．２％和９５±１．５％，对Ｏ＿２的消除效率明显强于维生素Ｃ和Ｅ，对不同工艺制备的ＴＰ消除活性氧自由基作用的测定结果显示：脱咖啡碱程度高，ＥＧＣ和Ｌ－ＥＧＣＧ含量比例高的ＴＰ－３制剂消除Ｏ＿２的效率最高．因此，ＴＰ消除有害自由基，中断或终止自由基的氧化反应是抗突变，抗肿瘤作用的主要机制 相似文献
3.
从NOLAN模型看我国企业管理信息系统的发展 总被引：3，自引：0，他引：3
从ＮＯＬＡＮ模型看我国企业管理信息系统的发展寿志勤（合肥工业大学预测与发展研究所２３０００９）１引言企业管理信息系统（ＭＡＮＡＧＥＭＥＮＴＩＮＦＯＲＭＴＩＯＮＳＹＳＴＥＭ，ＭＩＳ）不是一个单纯的计算机技术系统，而是集企业的社会环境、技术环境和数据环境... 相似文献
4.
ＱＵＡＮＴＵＭＣＨＥＭＩＣＡＬＳＴＵＤＩＥＳＯＮＡＮＥＷＯＲＧＡＮＯＳＵＬＦＵＲＲＥＡＣＴＩＯＮＭＥＣＨＡＮＩＳＭＺｈｕＪｉｎ；ＣｈｅｎＹａ－ｌｉｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｓｔｒｙ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｂｅｉｊｉｎｇ１０００８０... 相似文献
5.
ＡＮＯＴＥＯＮＦＩＲＳＴＰＡＳＳＡＧＥＴＩＭＥＳＦＯＲＧＩ／Ｍ／１ＴＹＰＥＭＡＲＫＯＶＰＲＯＣＥＳＳＥＳ￥Ｘｕｅ－Ｍｉｎｇ；Ｙｕａｎ（ＩｎｓｔｉｔｕｔｅｏｆＡｕｔｏｍａｔｉｏｎ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｂｅｉｊｉｎｇ，１００... 相似文献
6.
Liang Hua 《中国科学院研究生院学报》1994,(1)
ＯＮＡＳＹＭＰＴＯＴＩＣＮＯＲＭＡＬＩＴＹＩＮＡＳＥＭＩＰＡＲＡＭＥＴＲＩＣＭＯＤＥＬ￥ＬｉａｎｇＨｕａ（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＳｃｉｅｎｃｅ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｂｅｉｊｉｎｇ１０００８０）Ａｂｓｔｒａｃｔ：Ｓｕｐｐｏｓｅｔ... 相似文献
7.
Shiquan Wu 《中国科学院研究生院学报》1994,(1)
ＥＮＵＭＥＲＡＴＩＯＮＳＯＦＳＥＭＩＯＲＤＥＲＳ￥ＳｈｉｑｕａｎＷｕ（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓ，ＡｃａｄｅｍｉａＳｉｎｉｃａＰ．Ｏ．Ｂｏｘ２７３４，Ｂｅｉｊｉｎｇ１０００８０）Ａｂｓｔｒａｃｔ：ｉｎｔｈｉｓｐａｐｅｒ... 相似文献
8.
DETERMINATION OF CYANIDE BY A SPECTROPHOTOMETRIC REVERSED FLOW INJECTION METHODMa Yao Zhang Jianzhong 《中国科学院研究生院学报》1994,(1)
ＩＤＥＮＴＩＦＹＩＮＧＳＣＡＮＶＥＮＧＩＮＧＥＦＦＥＣＴＳＯＦＡＮＴＩＯＸＩＤＡＮＴＳＯＮＡＣＴＩＶＥＯＸＹＧＥＮＢＹＡＮＥＷＳＹＳＴＥＭ￥ＭａＹａｏ；ＺｈａｎｇＪｉａｎｚｈｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＧｒａｄｕａｔｅＳｃｈｏ... 相似文献
9.
ＤＥＴＥＲＭＩＮＡＴＩＯＮＯＦＣＹＣＬＯＴＲＩＭＥ－ＴＨＹＬＥＮＥＴＲＩＮＩＴＲＡＭＩＮＥＩＮＳＥＲＵＭＯＦＲＡＢＢＩＴＢＹＲＰ－ＨＰＬＣＣｈｅｎＹｏｎｇ；ＹｕａｎＺｈｕｏ－ｂｉｎ（ＧｒａｄｕａｔｅＳｃｈｏｏｌ，ＡｃａｄｅｍｉａＳｉｎｉｃａ．Ｂｅｉｊ... 相似文献
10.
用单光子吸收法（ＳＰＡ）对杭州市汉族５０岁以上的８０例非胰岛素依赖性糖尿病（ＮＩＤＤＭ）患者和年龄、性别与ＮＩＤＤＭ患者相配对的４３１名正常人的前臂尺、桡骨骨密度（ＢＭＤ）进行测定，发现女性轻中型和重型组、男性重型组ＮＩＤＤＩＭ患者的尺桡骨平均ＢＭＤ显著地低于正常人（Ｐ＜０．０１）；本组ＮＩＤＤＭ患者（男女合计）的一般性骨质疏松症（ＧＯＰ）和进行性骨质疏松症（ＰＯＰ）的发病率分别为６３．７５％和８．７５％，与正常人组相比较差异非常显著（Ｐ＜０．０１）；不同病程ＮＩＤＤＭ患者组别间尺桡骨平均ＢＭＤ的差异不显著（Ｐ＞０．０５），提示ＮＩＤＤＭ的病程与ＢＭＤ的相关程度不密切。 相似文献
11.
五种五味子属药用植物及东紫苏的化学成分和生物活性研究 总被引：1，自引：0，他引：1
对五种五味子属(Schisandra)药用植物（小花五味子Schisandra micrantha,狭叶五味子S. lancifolia,滇翼梗五味子S. henryi var. yunnanensis var. yunnanensis,复瓣黄龙藤S. Plena,华中五味子S. sphenanthera）和唇形科植物东紫苏 (Elsholtzia bodinieri) 的化学成分进行了研究,从中共分离鉴定了101个化合物,26个为新化合物。首次从3种五味子属植物中发现了3种高度氧化的新奇骨架类型。此外,还发现了18,19-seco-乌索酸型苷和17,20断裂并失去17位侧链的羊毛甾烷型和环阿尔廷型八降三萜等新的骨架类型。 对分离得到的部分化合物进行了体外抗HIV-1、急毒、抗炎和抗肿瘤活性实验,发现部分化合物具有抗HIV-1活性。其中化合物SM-10和SM-26具有显著的抑制HIV-1病毒活性,选择指数分别为174.08和 >25.04。且毒性较小,作为作用于病毒与细胞结合和融合靶点的小分子化合物具有重要的意义。 相似文献
12.
课堂活动是语言教学中的重要载体,也是实现教学目标的有效手段.教学活动的设计与实施对教学质量、教学效果和教学目标的实现起着关键性的作用.本文对课堂活动的设计原则、主要组织形式及特点做了阐述,并对如何实施做了探讨,为完善课堂活动做了一些尝试. 相似文献
13.
14.
This paper develops a people-centric perspective on the geographical dispersion of technological renewal in the multinational corporation (MNC). We contend that a large proportion of all foreign technological advancements can be attributed to a handful of individual inventors, suggesting a blockbuster effect of subsidiary technological development. This suggests that analyses carried out at the subsidiary or firm level disguise significant yet largely unexplored variation in the technological contributions made by individual members of these foreign units. To support this proposition, the paper draws upon an original data set that comprises all of the advanced foreign subsidiaries of 21 Swedish MNCs between 1893 and 2008, and follows their patenting activity in order to document the distribution of inventive activity, both across and within individual subsidiaries. The findings at the subsidiary level show that the distribution of technological activity and contribution to the overall multinational group is significantly skewed; the paper then empirically explores the assumption that a similar distribution also applies at the level of individual inventors. The results point to a pattern whereby most inventors make only occasional and limited technological contributions and, instead, more significant numbers of new technological discoveries are attributable to a select group of exceptionally inventive individuals. In the light of the results, we suggest the fruitfulness of applying a people-centric perspective on the sources of sustained competitive advantage of the MNC, the management of geographically dispersed capabilities in the multinational network, and the geographical sources of technological renewal in the MNC. 相似文献
15.
运用问卷调查等研究方法,对江西省南昌市部分小学4-6年级的学生参加大课间活动的态度进行了调查,并对其对策进行了研究。结果显示：60%多的学生认为大课间活动应该以自由结合的方式进行,80%多的学生认为大课间活动对他们整体素质的提高有较大帮助。 相似文献
16.
螺旋理论认为，几乎所有的有机化合物结构中都存在螺旋，螺旋结构是导致旋光性的根本原因。左手螺旋左旋；右手螺旋右旋。化合物的总旋光方向是由分子结构中所有螺旋旋光度的代数和所决定。各种不同类型的化合物都遵从该理论。光学活性的环芃烷结构特殊，变化也很大。这类化合物构型规定中的P, M螺旋 ( plus or minus helix )，不是唯一的螺旋，也不一定都是旋光贡献最大的螺旋，应对其进行具体分析。只要仔细分析每一个化合物结构中存在的螺旋，就会发现，它们和其他类型的光学活性化合物一样，都遵从螺旋理论的规律。由化合物的绝对构型，可以预测其旋光方向；反之，由旋光方向可以推断其绝对构型。 相似文献
17.
R. L. Gupta Sundeep Jain V. Talwar H. C. Gupta P. S. Murthy 《Indian journal of clinical biochemistry : IJCB》1999,14(1):12-18
Based on our demonstration earlier that ethanol extract, water extract and a compound purified from garlic possessedin vitro antitubercular activity against drug resistant and susceptibleMycobacterium tuberculosis, we tried the effect of garlic extract in 30 patients of tubercular lymphadenitis. For ethical considerations, two groups
of patients, 30 each, were given antitubercular therapy (ATT) consisting of isoniazid, rifampicin, ethambutol and pyrazinamide
for 30 days. For the next 15 days (31 to 45 days) group 1 patients received 3–6 garlic pearls per day in addition to ATT while
group 2 patients received ATT only. From 46th day onwards both the groups received ATT only for 6–8 months. Antitubercular
activity of the serum samples collected on 45th day was assessed by its effect on the growth ofM. tuberculois. The serum of group 1 patients showed significantly much higher antitubercular activity than that of group 2 patients. Further,
there was relief of dyspeptic symptoms caused by ATT therapy in patients of group 1 with garlic plus ATT therapy but no change
in group 2 patients with ATT only. Liver function and hematological tests were normal in both the groups after 6 months of
therapy. Garlic extracts or compounds have a good potential as antitubercular(s) drug if given as a supplement to ATT. 相似文献
18.
A microfluidic device combined with a light modulation system was developed to assess the inhibitory effect of carrageenan on Dengue virus (DENV) infection via real-time monitoring of cellular oxygen consumption rates (OCRs). Measuring cellular OCRs, which can reflect cellular metabolic activity, enabled us to monitor the process of viral infection in real time and to rapidly determine the antiviral activity of potential drugs/chemical compounds. The time variation of the cellular OCR of single cells that were infected in situ by DENV at different multiplicity of infection (m.o.i.) values was first successfully measured within a microfluidic device. The influence of the timing of carrageenan treatment on DENV infection was then examined by real-time monitoring of cellular OCRs in three groups. Cells that were pre-treated with carrageenan and then infected with DENV served as a pre-treatment group, cells to which carrageenan was added simultaneously with DENV served as a virucide group, and cells that were pre-infected with DENV and then treated with carrageenan served as a post-treatment group. By monitoring cellular OCRs, we could rapidly evaluate the inhibitory effect of carrageenan on DENV infection, obtaining a result within 7 h and showing that carrageenan had strong and effective anti-DENV activity in the three groups. In particular, a strong inhibitory effect was observed in the virucide group. Moreover, once the virus enters host cells in the post-treatment group, the immediate treatment with carrageenan for the infected cells has higher efficiency of antiviral activity. Our proposed platform enables to perform time-course or dose-response measurements of changes in cellular metabolic activity caused by diseases, chemical compounds, and drugs via monitoring of the cellular OCR, with rapid and real-time detection. This approach provides the potential to study a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery. 相似文献
19.
G. R. Sajitha K. T. Augusti Regi Jose 《Indian journal of clinical biochemistry : IJCB》2016,31(3):260-269
Heavy metal pollution is a global public health challenge due to its stable and persistent environmental contamination. Of these lead is considered to be one of the most common ubiquitous and industrial pollutants and at low concentration it exerts extensive damages to the tissues. Daily feeding of lead acetate solution (Dose: 10 mg/kg/day) to normal rats for a month adversely altered the parameters of blood, serum and tissues, viz; RBC, WBC, Hb, ?- ALAD (Delta amino levulinic acid dehydratase), Pb content, lipids, oxidized lipids (TBARS), vitamins C and E and GSH levels and activities of AST, ALT and antioxidant enzymes viz; catalase, GR, Gpx and SOD. In order to study whether antioxidants have any effect to counteract the toxicity of lead we have selected comparatively better active allium fractions for the study viz: polar fraction of garlic (PFG) and polar fraction of onion (PFO). On feeding of these active fractions of garlic and onion oils i.e. their polar fractions and vitamin E (Dose 100 mg/kg/day) separately for a month along with or without lead acetate to rats each nutraceutical and vitamin E counteracted the adverse effects of Pb significantly (p ≤ 0.05). Their effects are in the order of PFG > PFO > Vitamin E. All these results point out that garlic and onion oils contain natural disulfoxide compounds which act as antioxidant and anti toxic to lead compounds. Their comparative differences in action may be due to the presence and position of double bonds and disulfide oxide bonds in their molecules. i.e., in PFG the allyl disulfide oxide group is present and in PFO saturated methyl and propyl groups and unsaturated propenyl group are present in place of allyl groups. The former group confers a better antioxidant activity on PFG, while the latter groups confer a lesser activity on PFO. 相似文献
20.
Maternal and fetal indicators of oxidative stress during intrauterine growth retardation (IUGR) 总被引：1，自引：0，他引：1
Ullas Kamath Guruprasad Rao Shobha U Kamath Lavanya Rai 《Indian journal of clinical biochemistry : IJCB》2006,21(1):111-115
The present study demonstrates the possibility of increased lipid peroxidation and protein oxidation in both maternal and
fetal erythrocytes as markers of oxygen radical activity during intrauterine growth retardation. The erythrocyte MDA levels
were significantly elevated in mothers of IUGR babies when compared to controls (p<0.01). The endogenous protein damage due
to oxidative stress was significantly higher in IUGR mothers when compared to controls (p<0.05). Similarly the proteolytic
activity in erythrocyte lysates against oxidatively damaged hemoglobin was significantly increased in mothers of IUGR babies
compared to controls (p<0.001).
In fetuses born with IUGR, both lipid peroxidation and proteolytic activity were significantly increased when compared to
normal newborns (p<0.01).
The result of this study indicates that oxidative stress was induced both in IUGR babies and their mothers which is manifested
as increased lipid peroxidation and protein oxidant damage. 相似文献