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1.
Objective: A series of 4-aryl substituted semicarbazones of levulinic acid (4-oxo pentanoic acid) was designed and synthesized to meet the structural requirements essential for anticonvulsant activity. Methods: All the compounds were evaluated for anticonvulsant activity. Anticonvulsant activity was determined after intraperitoneal (i.p.) administration to mice by maximal electroshock (MES) and subcutaneous metrazol (ScMet) induced seizure methods and minimal motor impairment was determined by rotorod test. Results: A majority of the compounds exhibited significant anticonvulsant activity after intraperitoneal administration. In the present study 4-(4'-fluoro phenyl) levulinic acid semicarbazone emerged as the most active molecule, showing broad spectrum of activity with low neurotoxicity. Unsubstituted levulinic acid semicarbazone was found to be inactive in all the screens. Conclusion: The results obtained validate the hypothesis that presence of an aryl group near the semicarbazone moiety is essential for anticonvulsant activity. The results also indicate that the hydrophilic-hydrophobic site can accommodate hydrophilic groups.  相似文献   

2.
The correlation of serum arylesterase (PON1) activity on phenylacetate determined by an integrated method to classical biochemical indexes of liver damage was investigated for the use of PON1 activity to evaluate liver damage. PON1 reaction curve as absorbance at 270 nm for 0.20 mmol/L phenylacetate hydrolysis was analyzed by the integrated method to determine maximal PON1 reaction rate. Classical biochemical indexes of liver damage were determined routinely. The 95% confidence threshold of PON1 activity in sera from healthy individuals was 2.12 mkat/L [(4.73±1.31) mkat/L, n=105]. PON1 activity in clinical sera was closely correlated to serum albumin, total protein and the ratio of albumin to globulins, but was weakly correlated to both direct and total bilirubin in serum. There were no correlations of PON1 activity to γ-glutamyltransferase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase. Among 127 clinical sera with PON1 activity＞2.12 mkat/L, there were 92% healthy individuals examined by albumin, 90% healthy individuals examined by total protein, 88% healthy individuals examined by total bilirubin, 86% healthy individuals examined by direct bilirubin and 64% healthy individuals examined by the ratio of albumin to globulins, respectively. In each group of healthy individuals judged by classical biochemical indexes of close correlation to PON1 activity, percentage of healthy individuals examined by PON1 activity was always ＞80%. These results suggested PON1 activity on phenylacetate estimated by the integrated method was also suitable for the evaluation of liver damage.  相似文献   

3.
The geometries of azobenzene compounds are optimized with B3LYP/6-311 G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWFπ-π=-8.1537 6.5638BLN-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules' orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).  相似文献   

4.
In the present research, a series of 5,6-bis aryl 1,2,4-triazines 5a~5f were synthesized by condensation of various benzils 4a~4f with aminoguanidine bicarbonate and were screened in vivo, for their anticonvulsant and neurotoxicity studies. Compounds 5a, 5b and 5d were found to be potent molecules of this series, when compared with the reference drugs phenytoin sodium, diazepam and lamotrigine. The structures of these compounds were established by IR, 1H NMR, 13C NMR and mass spectroscopic data.  相似文献   

5.
Understanding life on a molecular level is greatly enhanced when students are given the opportunity to visualize the molecules. Especially understanding DNA structure and function is essential for understanding key concepts of molecular biology such as DNA, central dogma and the manipulation of DNA. Researches have shown that undergraduate students typically lack a coherent view of concepts and their relationships when studying molecular biology within instruction-based lecture with no other pedagogical applications. In this study, we have designed an experimental to investigate the effect of a hands on paper models exercise within group work （Jigsaw Cooperative learning） on student biology teachers＇ academic achievement and attitudes to biotechnologies. Our goal was to develop a manipulative activity using inexpensive but graphic materials. The sample for this study consisted of 42 student teachers in the department of Biology Education during the 2005-2006 academic year. We have divided the students in two different classes. One of the classes was randomly assigned as the non-paper model （control, n=21） and the other as the paper model group （n=21）. In experimental group cut and paste paper models exercise within cooperative groups, in control group traditional instructional design has been applied in teaching DNA structure, Central Dogma and Recombinant DNA. The posttests of the groups in achievement and attitudes to biotechnologies show significant differences. The results indicated that the paper model group was more successful than the non-paper group.  相似文献   

6.
To explore the effect of particle size on the quality uniformity and in vitro release performance of Strychnosnux-vomica powder, seven samples of Strychnos nux-vomica powder with different particle sizes were prepared.Microstructures and particle sizes were analyzed, and high performance liquid chromatography （HPLC） was used totest the contents and in vitro release performances of brucine and strychnine in the samples. Results showed that thecontents and the in vitro release rates of brucine （or strychnine） in different samples were different since there aredifferent proportions of endosperms to epidermal cells in Strychnos nux-vomica powder with different particle sizes.Brucine and strychnine in each sample were promptly released in the first ten minutes and their cumulative releaserates were higher than 70% after ten minutes. Eighty minutes later, the cumulative release rate tended to be a constant.Considering the quality uniformity and safety of Strychnos nux-vomica powder used as traditional Chinese medicine, itwould be better to control the particle size of Strychnos nux-vomica powder between 100 and 140 mesh in which themaximum cumulative release rate in vitro of brucine and strychnine can be relatively low within this range.  相似文献   

7.
Objective： To identify compounds that may be responsible for catnip response of Actinidia macrosperma, and compare chemical compositions in the wild and in vitro regenerated plants. Methods： GC-MS and relative retention indices with n-alkanes as reference points were used for compound identification, and component relative percentage was calculated based on GC peak areas without using correction factors. Results： There are 28 compounds （92.72%） and 15 compounds （93.88%） identified in the essential oils from the wild and regenerated plants, respectively. Dihydronepetalactone, iridomyrmecin, and dihydroactinidiolide, which are believed to be attractive to felines, are present in both wild and regenerated plants. Actinine was not detected, and beta-pheylethyl alcohol was only present in wild plant, in addition, short-chain enol derivatives, messengers in chemical communication, are commonly present in wild plant of A. macrosperma, but absent in regenerated one. Conclusion： Dihydronepetalactone, iridomyrmecin, and dihydroactinidiolide are responsible for the catnip response ofA. macrosperma.  相似文献   

8.
The effects of salinity （50 mmol/L NaCI） and Cd （1 μmol/L CdCl2） as sole and combined on growth and photosynthetic parameters were studied using two soybean genotypes, Huachun 18 and NGB. The concentrations of Cd^2＋, Zn^2＋, Ca^2＋, Mg^2＋, K^＋ and Na^＋were also determined in seeds and pods. Huachun 18 suffered a more serious decrease than NGB in net photosynthetic rate （P,） in the treatments of salinity stress alone and combined stress （NaCl＋Cd）, showing that it is relatively sensitive to salinity. The decrease in P, caused by salt stress in Huachun 18 was mainly due to the reduced total chlorophyll content and photosynthetic efficiency （the ratio of variable fluorescence to maximal fluorescence, Fv/Fm）, whereas the decease in NGB was mainly related to reduced stomatal conductance （Gs）, The combined stress of both Na and Cd did not induce further decrease in photosynthesis and fluorescence in the two genotypes relative to salt or Cd stress alone. Greater change in the pod concentrations of Zn^2＋, Ca^2＋, Mg^2＋, K^＋ and Na^＋was detected under salt stress for Huachun 18 than for NGB. The results suggested that the interactive effect of NaCl-Cd on growth and nutrient uptake differs between the two soybean genotypes.  相似文献   

9.
Obtaining an electrocorticograms （ECoG） signal requires an invasive procedure in which brain activity is recorded from the cortical surface. In contrast, obtaining electroencephalograms （EEG） recordings requires the non-invasive procedure of recording the brain activity from the scalp surface, which allows EEG recordings to be performed more easily on healthy humans. In this work, a technique previously used to study spatial-temporal patterns of brain activity on animal ECoG was adapted for use on EEG. The main issues are centered on solving the problems introduced by the increment on the interelectrode distance and the procedure to detect stable frames. The results showed that spatial patterns of beta and gamma activity can also be extracted from the EEG signal by using stable frames as time markers for feature extraction. This adapted technique makes it possible to take advantage of the cognitive and phenomenological awareness of a normal healthy subject.  相似文献   

10.
Based on the Bhatnagar-Gross-Krook distillation for two components in the presence equation, a new scheme of wiped-film molecular of inert gas is developed. The equations in the scheme are solved numerically by the method of finite difference and iteration. The new scheme is used to simulate the molecular distillation of dibutyl phthalate and dibutyl sebacate （ DBP-DBS ） mixture. The effects of the inert gas pressure, the distance between the evaporation surface and condensation surface, the rotation rate of blade, and the number of blades on the distillation rate and separation factor are discussed.  相似文献   

11.
Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of γ-aminobutyric acidA (GABAA) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly.However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion:The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.  相似文献   

12.
用分子力学、分子模拟退火动力学、量子化学等方法对转化生长因子-β受体激酶(TβR-Ⅰ)的取代吡唑类抑制剂进行了结构优化.用遗传算法(GFA)并结合多元线性回归技术(MLR),对该类抑制剂进行了定量构效关系研究,筛选出了影响抑制剂活性的主要因素,建立了定量构效关系方程(QSAR).结果表明,抑制剂分子的最高占据轨道能量EHOMOJ、urs的面积加权部分负电荷表面积WNSA1等是影响AHSPs抑制活性的主要分子参数.所得模型对该类化合物关于TβR-Ⅰ的抑制活性有良好的评估和预测效果(R=0.977,R2cv=0.864,s=0.178,F=51.93).  相似文献   

13.
取代硝基芳烃生物毒性与结构的相关性   总被引：1，自引：0，他引：1  
采用半经验量子化学AMl方法和分子图形学技术，获得24种取代硝基芳烃的电子结构和立体结构参数，并将这些参数与取代硝基芳烃对斜生栅列藻的生物毒性相关联．结果表明，取代硝基芳烃的斜生栅列藻生物毒性与最低空轨道能(ELUMO)、最小立体差异(MSD)两种参数相关性较好，成功地建立了取代硝基芳烃的构效关系方程式．找出了影响取代硝基芳烃的斜生栅列藻生物毒性的主要结构因素．  相似文献   

14.
介绍了路易斯电子八隅律即LEDS的基本规则,在预测分子反应活性、分子构型、表观电荷、分子拓扑结构以及分子轨道化方面的应用,指出了LEDS在共振、缺电子化合物、固态化学、过渡金属化合物、超价化合物的结构预测等方面存在的问题,展望了LEDS的改进途径.  相似文献   

15.
利用Gaussian03W在LANL2DZ基组水平对有机锡氧四元杂环结构化合物(μ-O)2Sn2R4(R:Me,Et)进行理论研究,优化了几何构型,获得键参数,分析了化合物的Mayer键级,计算出分子体系能、分子最高占据轨道能和分子最低未占据轨道能,经Mulliken布居分析原子净电荷分布,计算出原子轨道对分子轨道的组成贡献。结果表明,除(μ-O)2Sn2Me4外的标题化合物均稳定,为有机锡氧四元杂环化合物(μ-O)2Sn2R4(R!Me)的合成提供理论基础。  相似文献   

16.
由叠氮乙酸乙酯1与氯化苄反应,合成叠氮化合物2,2与三苯基膦发生Staudinger反应制得膦亚胺3,3与异氰酸苯脂、肼通过串连aza-Wittig反应合成了3个新的咪唑啉酮衍生物5 a~5 c。用元素分析、IR1、H NMR表征了它们的结构。发现碳二亚胺与肼加成反应后再生成咪唑啉酮环时具有一定的选择性。  相似文献   

17.
设计合成了7个未见文献报道的含取代1,3,4-噻二唑的芳甲酰基脲类化合物,所有化合物的结构经IR、1HNMR和元素分析确证．初步生物测试结果表明,部分化合物具有一定的植物激素活性．  相似文献   

18.
运用G98W，采用STO－3G基组，对茂金属配合物{o－[OPh(CO2)(R)]Zr(C5H4SiMe3)2}（R：（1）.NO2，（2）.CN,(3).Ph,(4).OH,(5).Me)进行从头算研究，探讨这些配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律，以及一些前沿分子轨道的组成特征等，为催化活性研究和分子设计提供理论参考。  相似文献   

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