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通过荧光光谱法和紫外吸收光谱法研究了超氧化物歧化酶和茉莉酸甲酯之间的相互作用。经过荧光光谱法的研究表明,超氧化物歧化酶和茉莉酸甲酯的相互作用是一个静态猝灭的过程,它们之间是以氢键和范德华力结合的,同时得到超氧化物歧化酶和茉莉酸甲酯的结合位点数n,表观结合常数K和热力学参数ΔH,ΔG,ΔS。而根据非放射性能量转移的F rster理论和同步荧光光谱证明茉莉酸甲酯和超氧化物歧化酶的相互作用位点同时接近超氧化物歧化酶色氨酸(Trp)和酪氨酸(Tyr)残基。 相似文献
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以3-硅基环戊-2-烯酮为原料,用连串的烷基共轭加成-亲核烷基化方法,可方便地制得茉莉酮及二氢茉莉酮。 相似文献
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柱色谱分离纯化茉莉醛梁达文(广西玉林高等师范专科学校化学系玉林537000)茉莉醛是一种广泛用于洗涤剂、化妆品和食品的重要香料 ̄[1-4]。利用苯甲醛与庚醛在碱性条件下合成的茉莉醛,其主要副产物庚醛自缩物(2-正戊基-2-壬烯醛)对茉莉醛的香气质量影... 相似文献
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茉莉酮和二氢茉莉酮是一类名贵的香料,此类化合物的合成一直是人们所关注的问题。已有许多报道,其中包括庚醛、1-硝基庚烷与甲基乙烯基酮进行Michael加成和以硝代甘缩酮与庚醛进行硝-醛缩合制得1,4-二酮,再进行分子内缩合为二氢茉莉酮。这些合成方法,有的对反应条件要求较苛刻,不易操作,有的则反应步骤较多,收率低。最近,白俊才等以甲基乙烯基酮和1-己烯为原料,合成了二氢茉莉酮,此法虽然新颖,但氧硼杂环己烷中间体 相似文献
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洋茉莉醛中间体3,4-亚甲二氧基苯乙醇酸的合成与表征 总被引:1,自引:0,他引:1
茉莉醛又称胡椒醛,学名3,4-亚甲二氧基苯甲醛(3,4-methylenedioxy benzaldehyde),广泛应用于合成香料、医药、食品、日化、电镀等领域.目前全球洋茉莉醛生产主要集中在我国、日本、美国和欧盟,总产能约1万吨/年.我国和日本主要采用天然黄樟油路线合成洋茉莉醛.随着全球生产量的不断增大,黄樟油资源面临枯竭,研究和开发以简单化学品为原料的全合成方法成为当务之急[1][2].在酸催化下,以乙醛酸和胡椒环为原料合成3,4-亚甲二氧基苯乙醇酸,再经氧化得到洋茉莉醛的路线,具有工艺设备简单、三废少、收率高、产品纯度高等优点,成为替代黄樟油路线法较为理想的全合成路线[3][4]. 相似文献
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José A. Delgado María A. Uguina José L. Sotelo Beatriz Ruíz José M. Gómez 《Adsorption》2006,12(1):5-18
The adsorption of carbon dioxide and methane on silicalite pellets packed on a fixed bed has been studied. Equilibrium and
kinetic measurements of the adsorption of carbon dioxide and methane have been performed, and a binary adsorption isotherm
for carbon dioxide/methane mixtures has been obtained. A model based on the LDF approximation for the mass transfer has been
used to describe the breakthrough curves obtained experimentally. A PSA cycle has been proposed for obtaining methane with
purity higher than 98% from carbon dioxide/methane mixtures containing 38% and 50% methane, and its performance has been simulated
using the proposed model. The simulation results show that silicalite can be a suitable adsorbent for employment in a PSA
separation process for carbon dioxide removal from coalseam and landfill gases. 相似文献
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Ms. M. A. Majali K. B. Shah R. S. Mani 《Journal of Radioanalytical and Nuclear Chemistry》1981,65(1-2):287-295
A rapid and sensitive radioimmunoassay has been developed for the measurement of Human Chorionic Gonadotropin (HCG) in serum.
Human chorionic gonadotropin has been labelled with125I to attain a specific activity between 80–120 μCi/μg. Aqueous dioxane (74 vol. %) has been employed to separate the bound
and freehormone in the radioimmunoassay. The sensitivity of this technique has been found to be ∼1.5 mIU/ml of HCG. The intra
assay variation has been found to be less than 5% and inter assay variation has been found to be less than 12%. 相似文献
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Bruce E. Dale Justin Weaver F. Michael Byers 《Applied biochemistry and biotechnology》1999,77(1-3):35-45
The ammonia fiber explosion (AFEX) process, previously run only in a batch reactor, has been adapted to run on a twin-screw
extruder. The sugar yield of AFEX material after enzymatic hydrolysis has been increased up to 3.5 times over that of completely
untreated material. The ruminant digestibility of corn fodder has been increased up to 32% (from 54–71%) over completely untreated
material, and 23% (from 63–77%) over material extruded with no ammonia. Extrusion-treated material proved more digestible
by the ruminant at 48 h than material treated in the batch reactor. 相似文献
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A determination of ethanol is described, which is based on a purging system in conjunction with a photoionization detector. With that system a fast and reliable determination of ethanol in aqueous solutions is possible. The system has been used for the analysis of wine. The 3delta-detection limit has been 0.005% ethanol, the relative standard deviation 4.8 to 6.0% and the time constant of the entire analytical system 20 s. The photoionization detector has been also applied to the analysis of artificial and genuine human breath. A comparison with gas-chromatography and non-dispersive IR-detection has been proven the reliability of results. 相似文献
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A nucleoprotein has been isolated from the gonads of the Caspian sturgeon and its composition has been determined. It has been shown that it contains 55% of DNA, 2% of RNA, 36% of protamines, and about 7% of nonprotamine proteins of nonbasic nature. The nucleoprotein has been hydrolyzed with trypsin, and the amino acid compositions of some hydrolysis products have been studied. On the basis of the results obtained, the hypothesis has been put forward of a possible linkage of the DNA with the basic proteins. It has been shown that protamines react with the DNA through the basic amino acid residues located at various regions of their molecules. 相似文献
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Vilar S Estrada E Uriarte E Santana L Gutierrez Y 《Journal of chemical information and modeling》2005,45(2):502-514
The TOPological Substructural MOlecular DEsign (TOPS-MODE) approach has been used to predict the anti-HIV activity in MT-4 assays (Estrada et al., 2002) of a diverse range of purine-based nucleosides. A database of 206 nucleosides has been selected from the literature and a theoretical virtual screening model has been developed. The model is able of discriminating between compounds that have anti-HIV activity and those that do not, with a good classification level of 85% in the training and 82.8% in the cross-validation series. On the basis of the information generated by the model, the correct classification of practically 80% of compounds from an external prediction set has been achieved using the theoretical model. Furthermore, the contribution of a range of molecular fragments to the pharmacological action has been calculated and this could provide a powerful tool in the design of nucleoside analogues that show activity against the HIV. Finally, a QSAR model has been developed that allows quantitative data to be obtained regarding the pharmacological potency shown by this type of compound. 相似文献
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Orla McGaughey José Vicente Ros-Lis Aisling K. McEvoy Brian D. MacCraith 《Analytica chimica acta》2006,570(1):15-20
A sol-gel-based optical sensor for the measurement of relative humidity has been developed. It is based on the changes in fluorescence intensity and/or lifetime of the ruthenium complex, ruthenium(II)diphenylphenanthroline-dipyridophenazinehexafluorophosphate. Sensitivity to relative humidity has been demonstrated over the range 0-100% relative humidity. This sensor has been developed for application in the field of indoor air-quality monitoring and displays a limit of detection of 0.35% relative humidity and a resolution of 1.13% over the concentration range of interest (0-50% relative humidity). The effects of varying process parameters on the sensor performance were studied along with the effects of cross-sensitivity to molecular oxygen. 相似文献
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A nucleoprotein has been isolated from the gonads of the Caspian sturgeon and its composition has been determined. It has been shown that it contains 55% of DNA, 2% of RNA, 36% of protamines, and about 7% of nonprotamine proteins of nonbasic nature. The nucleoprotein has been hydrolyzed with trypsin, and the amino acid compositions of some hydrolysis products have been studied. On the basis of the results obtained, the hypothesis has been put forward of a possible linkage of the DNA with the basic proteins. It has been shown that protamines react with the DNA through the basic amino acid residues located at various regions of their molecules.M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 549–553, July–August, 1979. 相似文献