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991.
血清游离羟脯氨酸的快速检测 总被引:7,自引:0,他引:7
采用6300黄金系统氨基酸分析仪,在锂柱140min程序生理体液分析方法基础上,建立了血清游离羟脯氨酸(HYP)快速测定方法,并用该法检测了正常人及肾病(有或无肾小铧与肾间质纤维化)病人血清中游离HYP的含量;用该法完成分析的时间为24min,比原方法缩短了116min;该法重复性良好,日内RSD2.3%,日间RSD3.7%,回收率97%;纤维化组血清羟脯氨酸浓度显著高于无纤维化组(P<0.001)和健康对照组(P<0.001),用该指标显著增高判断肾纤维化,敏感性100%,特异性915,假阳性9%;该法是一种快速、准确、可靠的血清因浆羟脯氨酸定量检测方法,有利于大批量样品的快速测定,并可为临床判断肾病病人肾纤维化提供辅助诊断指标。 相似文献
992.
Christiane Ferradini Jacques Foos Lucien Gilles Didier Haristoy Jacques Pucheault 《Photochemistry and photobiology》1978,28(4-5):851-855
Abstract— The radiolytic studies of oxyhemoglobin or methemoglobin in neutral aerated aqueous solutions with formate ions, lead to three conclusions:
The oxidation of oxyhemoglobin by O- 2 is not important. The observed low oxidation yield is probably due to the slow reaction with hydrogen peroxide produced by O- 2 disproportionation.
The reduction of methemoglobin in γ radiolysis reaches a plateau which could be explained by structural considerations.
The reduction of methemoglobin by O- 2 ions, if it occurs, is relatively slow: k = 1.4 × 103 M -1 s-1 . But a problem remains concerning the spectral characteristics of the product. 相似文献
The oxidation of oxyhemoglobin by O
The reduction of methemoglobin in γ radiolysis reaches a plateau which could be explained by structural considerations.
The reduction of methemoglobin by O
993.
Fañanás FJ Granados A Sanz R Ignacio JM Barluenga J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(13):2896-2907
Bis(2-lithioallyl)amines derived from bis(2-bromoallyl)amines undergo intramolecular carbometallation of a lithiated double bond, giving dilithiated dihydropyrroles. The cyclizations are promoted by N,N,N',N'-tetramethylethylenediamine (TMEDA). Reaction of these intermediates with electrophiles allows the preparation of some new fused and nonfused five-membered functionalized heterocycles. Although 2-lithioallylamines do not suffer intermolecular carbometallation, dimerization products are obtained with their copper or zirconium derivatives. Finally, the application of this new reaction to 2-lithio-N-(2-lithioallyl)anilines leads to 3-lithiomethylindole derivatives, which are transformed to functionalized indole derivatives by reaction with electrophiles. 相似文献
994.
Chiral Ru-BsDPEN, (1R,2R)-N-p-benzenesulfonyl-1,2-diphenylethylenediamine, catalyst has been immobilized on a mesoporous molecular sieve of MCM-41 type successfully. A hybrid mesoporous molecular sieve was synthesized using a precursor bearing benzene group, which in organosilica were sulfonylated and reacted with (1R,2R)-l,2-diphenylethylenediamine and [RuC1E(p-cymene)]2 successively to afford immobilized catalyst. The Brunauer-Emmett-Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size decreased after immobilization of catalyst onto the mesoporous material. Enantioselective transfer hydrogenation of ketones catalyzed by immobilized catalyst showed the highest yield of 22.36% and e.e. value of 31.47% by using acetophenone as substrate when reaction time was 48 and 16 h respectively. 相似文献
995.
Semmar N Fenet B Gluchoff-Fiasson K Comte G Jay M 《Chemical & pharmaceutical bulletin》2002,50(7):981-984
A new flavonol tetraglycoside, together with four acylated derivatives, were isolated from the leaves of Astragalus caprinus. Their structures were elucidated by spectroscopic methods, mainly 2D NMR, as kaempferol-3-O-[[beta-D-xylopyranosyl(1-->3)-alpha-L-rhamnopyranosyl(1-->6)][alpha-L-rhamnopyranosyl(1-->2)]]-beta-D-galactopyranoside (1), its 3(Gal)-p-coumaric (2) and 3(Gal)-ferulic (3) esters, and its 4(Gal)-p-coumaric (4) and 4(Gal)-ferulic (5) esters. 相似文献
996.
Sanz R Castroviejo MP Fernández Y Fañanás FJ 《The Journal of organic chemistry》2005,70(16):6548-6551
Tandem Sonogashira coupling/5-endo-dig cyclization reactions on 2,3-dihalophenols suppose a straightforward entry to 4-halobenzo[b]furans, which can be easily transformed into 4-functionalized benzo[b]furans, that are difficult to synthesize by other procedures. On the other hand, the starting 2,3-dihalophenols are efficiently prepared from commercially available 3-halophenols, via their N,N-diethyl carbamates by selective lithiation at the 2-positions by treatment with s-BuLi/TMEDA or LDA at low temperature and reaction with halogen electrophilic reagents. 相似文献
997.
甲基丙烯酸甲酯聚合动力学和分子量模型及仿真 总被引:2,自引:0,他引:2
考虑甲基丙烯酸甲酯聚合过程中体积收缩,反应物和生成物的浓度变化,以及由于凝胶、玻璃化和笼闭等效应对各速率常数和物性参数的影响,从基元反应和物料平衡出发,推导了半间歇,有链转移剂参与情况下的聚合动力学和分子量模型。用模型仿真计算了聚合温度、引发剂、溶剂和链转移剂的种类和浓度等对甲基丙烯酸甲酯聚合动力学和聚合过程中分子量变化的影响规律,并与实验和文献数据进行比较。 相似文献
998.
Embarek Bentouhami Gilles M. Bouet Marie-José Schwing Mustayeen Ahmed Khan 《Journal of solution chemistry》2006,35(6):889-916
Protometric studies were performed in aqueous solutions at 25^C and 0.1 ,mol.dm−3 ionic strength (NaClO4) to determine the complexing abilities of eight (o-hydroxy-phenyl) mono- and di-methylenephosphonic acids (differently substituted by chromophoric or auxochromic groups) towards thorium(IV). The number, the nature of the species present in solution, their overall stability constants over a broad acidity range and their individual electronic spectra, as resolved by computation, have been determined by potentiometry and UV-visible spectrophotometry.The formation of 1:1 species, partially protonated MLHx and totally deprotonated [ML], as well as hydroxo species -- mononuclear ML(OH)x and dinuclear M2L(OH) x is reported with thorium(IV). The results show that the complexing power, which is not very different in the lanthanide series, is much higher for thorium(IV). The ratio Th4+/Eu3+ reaches eight log10 units with some of the ligands. 相似文献
999.
Studies of Polyhalides. 22. On Dimethyldiphenylammoniumpolyiodides (Me2Ph2N)In with n = 3, 13/3, 6, and 8: Preparation and Crystal Structures of a Triiodide (Me2Ph2N)I3, Tridecaiodide (Me2Ph2N)3I13, Dodecaiodide (Me2Ph2N)2I12, and Hexadecaiodide (Me2Ph2N)2I16 The new compounds [(CH3)2(C6H5)2N]I3, [(CH3)2(C6H5)2N]3I13, [(CH3)2(C6H5)2N]2I12 and [(CH3)2(C6H5)2N]2I16 have been prepared by the reaction of dimethyldiphenylammonium iodide [(CH3)2(C6H5)2N]I with iodine I2 in ethanol. Their crystal structures have been determined by single crystal X-ray diffraction methods. The structure of the triiodide may be described as a layerlike packing of pairs of nearly linear symmetric anions and tetraedral cations. The tridecaiodide forms zig-zag chains of iodide ions and iodine molecules with the iodide ion also weakly coordinated by two pentaiodide groups. The dodecaiodide is built from two pentaiodide-groups, which are bridged by an iodine molecule and connected with secondary bonds forming double chains. The hexadecaiodide ion forms layers built up from two heptaiodide groups and one iodine molecule. Thus the dimethyldiphenylammonium cation stabilizes a unique series of polyiodides of extraordinary composition and structure. 相似文献
1000.
Bedoux G Vallée-Réhel K Kooistra O Zähringer U Haras D 《Journal of mass spectrometry : JMS》2004,39(5):505-513
The lipid A components of the Pseudomonas aeruginosa strains PAO1 (wild-type) and derived mutants PAO1 algC::tet and PAO1 PDO100 were isolated after mild acetic acid hydrolysis of LPS. Their structural heterogeneities were characterized using electrospray ionization (ESI) ion-trap mass spectrometry (MS) with direct infusion in the negative ion mode without prior derivatization. The ESI-mass spectra revealed monophosphorylated molecules corresponding to known tetra-, penta- and hexaacylated structures of P. aeruginosa lipid A. The MS/MS fragmentation patterns allowed the location of fatty acyl chains on the disaccharide backbone of lipid A. In addition, a hexaacylated lipid A containing a hexadecanoyl chain was detected for the first time in strain P. aeruginosa PAO1. With multiple stages of fragmentation (MS(n)), the position of this hexadecanoyl chain O-linked to the decanoyl chain at the C-3(') position of the glucosamine backbone was determined. This sensitive method is suitable to reveal lipid A heterogeneity, i.e. the nature, number and distribution of acyl chains, without prior lipopolysaccharide purification. The lipid A from mutant strains were also characterized and significant differences were shown in the abundance of monophosphorylated lipid A components between the wild-type and the mutant strains. 相似文献