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排序方式: 共有269条查询结果,搜索用时 15 毫秒
1.
Alain Estve Adeline Bail Georges Landa Ahmed Dkhissi Marie Brut Mehdi Djafari Rouhani Jan Sudor Anne-Marie Gu 《Chemical physics》2007,340(1-3):12-16
Possible collapsed forms of poly(N-isopropylacrylamide) molecules are reviewed on the basis of first principle calculations. Various configurations and associated conformations are detailed. The calculated optimized structures exhibit different possibilities of creating networks of intra-molecular bonds of the hydrogen type. We show that the most remarkable one is able to form a local, self-saturated and well ordered helix. We also indicate in which direction the synthesis of the molecule should be oriented to improve its global behavior in term of hydrophobic/hydrophilic behavior. 相似文献
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BIOLOGICAL ACTIVITIES OF PHTHALOCYANINES-X. SYNTHESES AND ANALYSES OF SULFONATED PHTHALOCYANINES 总被引:5,自引:0,他引:5
Hasrat Ali Réjean Langlois J. Richard Wagner Nicole Brasseur Benoit Paquette Johan E. VAN Lier 《Photochemistry and photobiology》1988,47(5):713-717
Abstract— Synthetic methods to obtain selectively sulfonated metallo phthalocyanines are compared. Both condensation and direct sulfonation procedures lead to mixtures of mono- to tetrasulfonated products which are resolved by reverse phase liquid chromatography in buffered aqueous-methanol. The proportion of sulfonated derivatives is examined as a function of the starting reagents in the case of the condensation method, and as a function of the temperature and reaction time in the case of the direct sulfonation procedure. The number of sulfonate groups per phthalocyanine molecule is determined by oxidative degradation of the phthalocyanine ring followed by quantitative chromatographic analysis of the sulfophthalamide and phthalamide fragments. 相似文献
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M Berger J Cadet R Berube R Langlois J E van Lier 《Journal of chromatography. A》1992,593(1-2):133-138
High-performance liquid chromatography-thermospray mass spectrometry was applied to the analysis of various radiation-induced decomposition products of thymidine including N-(2-deoxy-beta-D-erythro-pentofuranosyl)formamide and the various diastereomers of 5,6-dihydroxy-5,6-dihydrothymidine, 5-hydroxy-5,6-dihydrothymidine and 5,6-dihydrothymidine. This method combines high sensitivity and product resolution, rendering it particularly useful for monitoring the formation of radiation-induced base damage within DNA. 相似文献
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An increasing number of hereditary diseases are becoming amenable to diagnosis by analysis of DNA as the responsible genes are located and identified. Gel electrophoresis of DNA fragments plays a central role in the diagnosis of hereditary disease. Electrophoretic separation of differently sized fragments enables the characterization or typing of normal variants which are known to be genetically linked to disease genes. For some diseases it is possible to directly detect mutations by DNA electrophoresis. Deletion mutants may be detected by a restriction fragment of altered size or by a failure to amplify a coding region with the polymerase chain reaction. Carriers of small deletions, involving a few base pairs, may be identified by DNA amplification which produces heteroduplexes that show characteristic, anomalous electrophoretic migration. Mutations that alter restriction sites also alter the sizes of restriction fragments. Common disease mutations that alter a single base pair may be detected using a pair of reactions with normal and mutant oligonucleotides under conditions where a perfect match is necessary for hybridization, amplification or ligation. Alternatively a mismatched oligonucleotide primer may be designed to generate a restriction site with either the normal or mutant allele, following DNA amplification. Finally a number of techniques are available that are useful as screening tools for novel mutations. 相似文献
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A sensitive gas-liquid chromatographic technique for the quantitative analysis of SCH-12679 (d-7,8-dimethoxy-3-methyl-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine acid maleate) and its major metabolites in plasma of aggressive mental retardates receiving therapeutic doses of the medicament has been developed. The lower limits of detection are 20 ng/ml for SCH-12679, 0.5 ng/ml for 3-desmethyl SCH-12679 and 0.4 ng/ml for 7-desmethyl plus 8-desmethyl SCH-12679. SCH-12679 is estimated with a flame ionization detector. Its metabolites are quantitated using an electron-capture detector after conversion of the compounds to their heptafluorobutyryl derivatives by reaction with the appropriate anhydride. Data on plasma levels of unchanged SCH-12679, 3-desmethyl SCH-12679 and a combination of 7-desmethyl and 8-desmethyl SCH-12679 in fifteen patients treated with the medicament are presented. 相似文献
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Awatef Ayadi Amani Jaafar Adeline Fix-Tailler Ghassan Ibrahim Gérald Larcher Abdelkrim El-Ghayoury 《Tetrahedron》2017,73(25):3554-3563
The synthesis of two tetrathiafulvalene-appended pyridinehydrazone pyrimidine ligands, namely (Z)-4-(2-((5-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L1 and (Z)-4-(2-((6-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L2 is described. Ligand L1 was reacted with cobalt(II) to yield a cationic metal complex [Co(L1)2] while ligand L2 was reacted with zinc(II) to afford a neutral metal complex [ZnL2Cl2]. The crystal structure analysis of [Co(L1)2] indicate that Co(II) ion is coordinated by six nitrogen atoms from two perpendicular ligands while in [ZnL2Cl2], Zn(II) is coordinated by two chlorine atoms and three nitrogen atoms. The electrochemical behavior indicate that ligands L1 and L2 and the zinc(II) complex are suitable fort the preparation of crystalline radical cation salts. Finally the determination of MIC80 values against C. albicans, C. glabrata, C. parapsilosis, C. krusei and E. dermatitidis revealed that the cobalt(II) metal complex [Co(L1)2] is active against all the studied fungi. 相似文献