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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.
Nanosized TiO2 particles,synthesized by microemulsion-mediated method,were characterized by XRD,TEM,EDS and BET.To judge the activity of TiO2 particles,the photocatalytic destruction of phenol in areated suspension was studied.The result shows that the photocatalytic activity of lab-made nanometer anatase TiO2 is comparable to or higher than that of commercial titania perticles.The effects of smoe processing parameters such as TiO2 content,oxygen flow rate,pH value on phenol removal were also investigated.The experimental results indicate that there is an optimum value for the TiO2 content,Sufficient O2 supply is needed, but too high gas flow rate induces large bubbles that eliminate the gas residence time and the gas/liquid contact interface,The pH value of the phenol solutions has a complex effect on the photocatalytic activity of the particles. 相似文献
3.
Variation in the limit dextrinase activity of barley malt, and the relationships between limit dextrinase activity and malt quality parameters were investigated using eight cultivars grown at seven diverse locations in China for two successive years. Limit dextrinase activity varied with genotype and location, with the levels ranging from 0.245 U/g to 0.980 U/g. The results showed that the variation in limit dextrinase activity was more attributable to the environment （location and year） than to the genotype. The response of limit dextrinase activity to the environment differed markedly among cultivars, and was reflected by large difference in coefficient of variation of cultivars across diverse locations. Regression analysis showed that limit dextrinase activity was negatively correlated with malt viscosity （r=-0.52, P〈0.01）, positively correlated with Kolbach index （r=0.38, P〈0.01） and malt extract （r=0.30, P〈0.05）, but had no significant correlation with malt protein content and diastatic power. 相似文献
4.
Emilia Martynowicz 《美中教育评论》2006,3(3):9-15,30
Values may be considered as generalized beliefs about what is or is not desirable and also as motives. The strength of a person＇s values may affect how much effort a person puts into an activity, how long a person persists at an activity, the way situations are construed, the affective responses that occur when an activity is undertaken unsuccessfully. Schwartz and Bilsky （1987, 1990） proposed that there are ten motivational types of values that could be derived from the three universal human requirements. Schwartz and Bilsky also specified sets of dynamic relation between the value types. The values that were incorporated into the value types were from the Schwartz Value Survey that contained 56 values covering a wide range of content. The value types proposed by Schwartz （1992）were： power, achievement, hedonism, stimulation, self-direction, universalism, benevolence, conformity, tradition and security. The results of the research that I am presenting refer to relations between value types preferred and accepted by young people and goals life, a temporal orientation, worries, some of personality traits. 相似文献
5.
The reality show is gaining its popularity all across America as well as the world.It’s more than a TV show and commercial activity;because it reveals American values that embody individualism,which is what the analysis is mainly about and there is a conclusion that it is strongly embraced by the Americans nowadays,along with the evident traces of edgy personality,teamwork,and innovation. 相似文献
6.
Bing FENG Lai-ji MA Jin-jing YAO Yun FANG Yan-ai MEI Shao-min WEI 《Journal of Zhejiang University. Science. B》2013,14(2):97-105
Oat contains different components that possess antioxidant properties;no study to date has addressed the antioxidant effect of the extract of oat bran on the cellular level.Therefore,the present study focuses on the investigation of the protective effect of oat bran extract by enzymatic hydrolysates on human dermal fibroblast injury induced by hydrogen peroxide(H2O2).Kjeldahl determination,phenol-sulfuric acid method,and high-performance liquid chromatography(HPLC) analysis indicated that the enzymatic products of oat bran contain a protein amount of 71.93%,of which 97.43% are peptides with a molecular range from 438.56 to 1 301.01 Da.Assays for 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity indicate that oat peptide-rich extract has a direct and concentration-dependent antioxidant activity.3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) colorimetric assay and the TdT-mediated digoxigenin-dUTP nick-end labeling(TUNEL) assay for apoptosis showed that administration of H2O2 in human dermal fibroblasts caused cell damage and apoptosis.Pre-incubation of human dermal fibroblasts with the Oatp for 24 h markedly inhibited human dermal fibroblast injury induced by H2O2,but application oat peptides with H2O2 at same time did not.Pre-treatment of human dermal fibroblasts with Oatp significantly reversed the H2O2-induced decrease of superoxide dismutase(SOD) and the inhibition of malondialdehyde(MDA).The results demonstrate that oat peptides possess antioxidant activity and are effective against H2O2-induced human dermal fibroblast injury by the enhanced activity of SOD and decrease in MDA level.Our results suggest that oat bran will have the potential to be further explored as an antioxidant functional food in the prevention of aging-related skin injury. 相似文献
7.
This paper describes a debate held in the author‘s medicine major freshmen in class. The activity is intended to encourage students‘ autonomy, and to train students how to acquire various skills in language learning and communication. Through this activity, the students can get enough space to exert their autonomy, and the author can obtain her desired goals too: The center of teaching and learning shifts from the teacher to the students, that is, the students-centered teaching; given autonomous learning environment, students can learn more effectively; and students can acquire relevant abilities. 相似文献
8.
Effect of glycine site/NMDA receptor antagonist MRZ2/576 on the conditioned place preference and locomotor activity induced by morphine in mice 总被引：3，自引：0，他引：3
Objective： To study the effect of glycine site/NMDA （N-methyl-D-aspartate） receptor antagonist MRZ2/576 on the conditioned place preference （CPP） and locomotor activity induced by morphine in mice. Methods： Different doses （1.25, 2.5 and 5 mg/kg, i.p.） of MRZ2/576 were used to evaluate the effect of MRZ2/576 on the acquisition and expression of CPP induced by morphine （5 mg/kg） in mice. In addition, we examined the locomotor activity of mice in conditioning and testing phase of CPP paradigm. Results： MRZ2/576 alone could not establish place preference, but a 5 mg/kg dose of MRZ2/576 could block both acquisition and expression of morphine-induced CPP. In testing phase of CPP, there was no statistical difference for locomotor activity between the groups; injection of MRZ2/576 showed a dose-dependent decrease of locomotor activity on both control and morphine-treated mice, especially 5 mg/kg of MRZ2/576 significantly suppressed the locomotor activity of mice. Conclusion： Based on the present results, we assume that MRZ2/576 can antagonize the rewarding effect of morphine, suggesting that this glycine site/NMDA receptor antagonist could be used to treat addictions due to its light side effect profile. 相似文献
9.
Directions:For each blank in the following passage there are four words or phrases marked A,B,C,and D.Fill in each blank with the word or phrase that best fits the context. Many people find that regular physical activity gives them an unexpected benefit.They sleep better and wake up feeling more 1,in part due to 相似文献
10.
Along with the economic globalization, the informationization arrival, electronic commerce becomes in the international trade activity one kind of important service form. In the international electronic commerce activity exists the communication exchange asked that the topic becomes the influence to trade the bilateral important attribute, how through the effective way to guarantee that the communication smooth has the necessity very much. In recent years regardless of commercial English in the fundamental research practiced in the application to make the remarkable progress, analysis commerce English was advantageous in the international electronic commerce’s application in enhances our country commerce English training and the practice level. 相似文献
11.
As the most active factor,the translator bears a positive function in translation activity,which is mainly displayed in the whole translation process,that is,before,during and after translation. 相似文献
12.
《英语辅导》2004,(4)
Backwards cities&terrible weddingsWe spend a lol of time teaching rulesand prohibitions.I find that students aremuch more willing to put time into a writ-ing activity if it is funny and anarchic,and if it lets them feel as if they are bend-int the rules.I use the following ideasto get students writing:‘In backwards city,nothingis as it should be.Stoplights 相似文献
13.
INTRODUCTION Telomeres are distinctive DNA-protein struc-tures that cap the ends of linear chromosomes.It is very important to keep the chromosomes stabilization.Telomerase activity is closely linked to attainment of cellular immortality,a step in carcinogenesis,while lack of such activity contributes to cellular senes-cence.Telomerase is activated in more than85%ofmalignant tumors(Hiayma et al.,1997).Human te-lomeric repeat binding factor1(TRF1)is a telomere associated with proteins a… 相似文献
14.
Aspergillus oryzae 3042 mycelium pellets were immobilized by crosslinking method with reagents of gelatin and formaldehyde. An orthogonal design table was used to determine the optimal immobilization conditions. The L-aminoacylase activity of immobilized mycelium pellets under optimal conditions was assayed. The results show that the L-aminoacylase activity was 1 350 U·g-1. and the activity retention rate was 83%. The properties of the immobilized preparation were studied. Compared with free pellets, the appropriate pH of reaction system changed from 7.0 to 8.0, temperature changed from 52℃to 63℃, and the ranges of the optimum reaction conditions were all improved. The effect of Co2 on immobilized mycelium pellets was investigated and the favorable concentration was determined. When the immobilized preparation was used for the resolution of D, L-alanine in a packed bed reactor with 10 mm in diameter, 200 mm in height, the operational stability was increased, and the half-life period was 53 d. Thermal stability analysis shows that the immobilized pellets were more stable than the free pellets. 相似文献
15.
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
16.
BOTASCHANJAN Jewgenij PISTER Markus RUMPE Bernhard 《Journal of Zhejiang University. Science. B》2004,(5)
INTRODUCTION One main purpose of requirements is to de-scribe the functionality of software. Thus re-quirements often serve as a basis for contracts aswell as for communication between customers anddevelopers. However, they are usually captured innatural language accompanied by a few top-levelinformal drawings like use cases or activity dia-grams that denote the structure of the functional-ities in an abstract way. One disadvantage of naturallanguage is that the developer has to cope with… 相似文献
17.
Birds can learn to choose the best building materials for their nests,according to scientists.It was previously thought that birds’choice of nest materials was determined by their genes,that is,each type of bird has their own methods of building nests born with them.But an experiment has now shown this to be a more complex activity.The study,published in the Royal Society Journal Proceedings B, 相似文献
18.
The basic assumption of reform mathematics is that ＂no one can teach mathematics＂. Therefore, the important teachers＇ role is to stimulate students to learn mathematics and support their development. Open-ended problem solving is an instructional strategy that creates interest and stimulates creative mathematical activity in the classroom through students＇ collaborative work. Lessons using openended problem solving problem solving activities result. emphasize the process of rather than focusing on the 相似文献
19.
For teachers
In 1954, the United Nations General Assembly suggested that all observe a Universal Children＇s nations should Day as a day of worldwide fraternity and understanding between children and of activity promoting the welfare of the world＇s children. 相似文献
20.
A new supported amorphous catalyst CoP/TiO2 was prepared by chemical reduction and characterized by ICP, XRD, TEM, BET and DSC Its application in decomposing PH3 to high purity phosphor and its catalytic activity were studied. The decomposition rate is over 95% at 450 ℃. For comparison, unsupported CoP amorphous catalyst was prepared by the same method. The result suggests that CoP/TiO2 exhibits higher thermal stability and catalytic activity than CoP, which is attributed to the high dispersion of CoP alloy particles on the support-TiO2. 相似文献