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121.
Bao‐Shiang Lee Sangeeth Krishnanchettiar Syed Salman Lateef Nabila Salman Lateef Shalini Gupta 《中国化学会会志》2006,53(3):745-750
Avidin functional affinity electrophoresis (AFAEP) is substituted for an avidin affinity column (AAC) to capture biotinylated peptides in the Isotope‐Coded Affinity Tagging (ICAT) technique which is a valuable tool in quantitative proteomics. In this new technique, the AFAEP‐captured ICAT‐labeled biotinylated peptides are extracted with the biotin tag intact from the polyacrylamide gel piece with aqueous 95% formamide (pH 8.2) at 65 °C for 20 min, and then detected by a matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer. Bovine serum albumin (BSA) and the 12C‐ and 13C‐ICAT reagents are used to test this AFAEP‐ICAT technique. The results show that both AFAEP and AAC methods provide quantitative information of the relative amounts of 12C‐ and 13C‐ICAT‐labeled biotinylated tryptic peptides of BSA in a sample. Compared with AAC, the AFAEP is cheaper to perform, more stringent in capturing the biotinylated peptides, and capable of simultaneously processing multiple samples. 相似文献
122.
Study of EPR, optical properties and electrical conductivity of vanadyl doped Bi2O3.PbO.B2O3 glasses
Gahlot PS Agarwal A Seth VP Sanghi S Gupta SK Arora M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(6):1189-1194
Heavy metal based oxide glasses having composition xBi(2)O(3).(0.30 - x)PbO.0.70B(2)O(3) have been prepared (0.00 < or = x < or = 0.15, mol%) containing 2.0mol% of V(2)O(5) by normal melt-quenching technique. Electron paramagnetic resonance (EPR), optical spectra and dc conductivity of these glasses have been studied. Spin Hamiltonian parameters (SHP) of VO(2+) ions, dipolar hyperfine parameter, P and Fermi contact interaction parameter, K, molecular orbital coefficients (alpha(2) and gamma(2)) and optical band gap have been calculated. It is observed that in these glasses, the tetragonal nature of V(4+)O(6) complex increases with Bi(2)O(3) content. Increase in Bi(2)O(3):PbO ratio results in the contraction of 3d(xy) orbit of the unpaired electron in the vanadium ion, and the SHP are dependent on the theoretical optical basicity, Lambda(th). In present glasses, the conductivity (activation energy) first decreases (increases) with increase in mol% of Bi(2)O(3) content upto x = 0.08 and then shows a maxima (minima) at x = 0.10 and then starts decreasing (increasing) upto x < or = 0.15 with mol% of Bi(2)O(3) content. 相似文献
123.
The enantiomeric resolution of (+/-)-ibuprofen into its enantiomers was achieved by TLC on silica gel plate using optically pure (-)-brucine as a chiral selector and acetonitrile-methanol (5:1, v/v) as the solvent system. Spots were located in an iodine chamber. The detection limit was 4.9 microg. The effect of concentration of the chiral selector, temperature and pH on resolution has been studied. 相似文献
124.
Salicylaldehyde reacts with dimethyl acetylenedicarboxylate in benzene solution to give a mixture of dimethyl o-formylphenoxymaleate, dimethyl o-formylphenoxyfumarate, 2,3-dicarbomethoxychrom - 2 - en - 4 - ol, 2,3 - dicarbomethoxychrom - 3 - en - 2 - ol, dimethyl (2,3 - dicarbomethoxychrom - 2 - en - 4 - yl) - oxalacetate and dimethyl fumarate. 2,3 - Dicarbomethoxychrom - 3 - en - 2 - ol in this reaction is formed from 2,3 - dicarbomethoxychrom - 2 - en - 4 - ol through a benzopyrylium intermediate. The reaction of salicylaldehyde with excess of dimethyl acetylenedicarboxylate, however, gives a mixture of 2,3 - dicarbomethoxychrom - 3 - en - 2 - ol and dimethyl (2,3 - dicarbomethoxychrom - 3 - en) - 2 - oxyfumarate. 2,3 - Dicarbomethoxychrom - 3 - en - 2 - ol itself reacts further with dimethyl acetylenedicarboxylate to give 2,3,12 - tricarbomethoxychrom - 3,4 - eno[2,3 - b] pyrone. Similarly, the reaction of o-hydroxyacetophenone with dimethyl acetylendicarboxylate gives a mixture of dimethyl o-acetylphenoxymaleate, dimethyl o-acetylphenoxyfumarate, 2,3 - dicarbomethoxy - 4 - methylchrom - 2 - en - 4 - ol and 2,3 - dicarbomethoxy - 4 - methylchrom - 3 - en - 2 - ol. Both 2-hydroxychalcone and 2 - hydroxy - 4′ - methoxychalcone give mixtures of chalcone - 2 - oxymaleate and chalcone - 2 - oxyfumarate. The reaction of 2,2t?-dihydroxychalcone, however, gives 2′-hydroxyflavone, in addition to the expected maleate and fumarate. Similar reactions of 5 - chloro - 2,2′ - dihydroxychalcone and of 3,5 - dibromo - 2,2′ - dihydroxychalcone, on the other hand, give 2,3 - dicarbomethoxy - 4 - (o - hydroxyphenacyl) - 6 - chlorochrom - 2 - ene and 2,3 - dicarbomethoxy - 4 - (o - hydroxyphenacyl) 6,8 - dibromochrom - 2 - ene, respectively, together with the corresponding maleates and fumarates. 相似文献
125.
Nuclear prenylation of naringenin (7) with 2-methylbut-3-en-2-ol in the presence of boron trifluoride etherate gives a mixture of 6-C-prenyl-(11), 8-C-prenyl-(15) and 6,8-di-C-prenyl-(8) derivatives. On formic acid cyclisation, 11 yielded two monodihydropyrans (12 and 13), but 15 afforded only one viz 16; similarly 8 formed the bisdihydropyran 10. Methylation of 8-C-prenyl naringenin (15) with Me2SO4 resulted in the formation of di-O-methyl derivatives of xanthohumol (22) and isoxanthohumol (23).
Cyclodehydrogenation of 6,8-di-C-prenyl-naringenin (8) with DDQ gave a mono-C-prenyl-2,2-dimethylpyran (1) corresponding to (±) lupinifolin. The angular isomer (2) was also formed. The structure of natural flemichin-B therefore needs further consideration. Similarly, cyclodehydrogenation of 6-C-(11)- and 8-C-prenyl-(15) naringenins afforded the corresponding linear (24) and angular (25) derivatives which have been characterized by conversion into known chalcones 26 and 27 by O-methylation. 相似文献
126.
Abstract— Interaction of naphthalene triplets with trans -piperylene leads to triplet energy transfer with unit efficiency. When cis -piperylene is used as a quencher of naphthalene triplets, the efficiency of triplet energy transfer is found to be 0–76 ± 004. The rest of the quenching encounters in this case lead to deactivation of naphthalene triplets, without energy transfer. 相似文献
127.
Zusammenfassung Es wurde festgestellt, daß die Mehrzahl der Amidoxime mit folgenden Ionen reagiert: Hg2+, Cu2+, Fe3+, Co2+, UO2
2+, Cd2+, Ag+;, Pb2+, Pd2+, Ni2+. Von den Malonsäure-bis-amidoximen wurden hergestellt die Silber-, Blei-, Cadmium-, Kupfer- und zwei Quecksilbersalze, von den Amidoximen der Nicotin- und Isonicotinsäure Palladium-, Kupfer-, Cadmium- und Bleisalze. Die Salzbildungsfähigkeit der Amidoximgruppe ist vom Radikal, von den Substituenten an der Amidgruppe und vom Reagens-medium abhängig. Die braunrote Färbung mit Fe3+-Ionen ist für alle Amidoxime typisch, diese Reaktion kann zum Nachweis der am Amidstickstoff nichtsubstituierten Amidoxime angewandt werden.IX. Mitteilung: Collect. czechoslov. chem. Commun. 24, 1720 (1959). — X. Mitteilung: Collect. czechoslov. chem. Commun. (im Druck). 相似文献
128.
Chaitan P Gupta 《Journal of Mathematical Analysis and Applications》1977,58(2):344-360
In this paper we study an interesting class of nonlinear integral equations of Urysohn's type, namely, . It is shown that such an equation can be considered as a nonlinear operator equation of Hammerstein type in an appropriate Banach space. One can in this way extend the theory of nonlinear operator equations of Hammerstein type (except for the part which uses variational methods) to this class of equations. 相似文献
129.
R. K. Gupta 《Proceedings Mathematical Sciences》1977,85(2):104-114
The following equation $$(1 - x^2 )d^2 y/dx^2 + [(\beta - \alpha - (\alpha + \beta + 2)x]dy/dx + (\chi (c) - c^2 x^2 )y = 0$$ has been solved wherex(c) a separation constant is the characteristic value and is a function ofc. This solution is a generalization of spheroidal wave function into the series form ofP n α;β (x),α andβ both separately are greater than ?1. The finite transform and its properties have been defined and a boundary value problem has been solved applying these tools. 相似文献
130.
Kalyan Kali Sen Gupta Saroj Chandra Kumar Pratik Kumar Sen Amalendu Banerjee 《Reaction Kinetics and Catalysis Letters》1988,36(2):423-428
The kinetics of oxidation of methanol by bromate ion in hydrochloric acid medium has been investigated. A mechanism consistent with the experimental observations is suggested.
. , .相似文献