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131.
Purkey HE Palaninathan SK Kent KC Smith C Safe SH Sacchettini JC Kelly JW 《Chemistry & biology》2004,11(12):2384-1728
Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) are known to bind to transthyretin (TTR) in vitro, possibly explaining their bioaccumulation, rodent toxicity, and presumed human toxicity. Herein, we show that several OH-PCBs bind selectively to TTR in blood plasma; however, only one of the PCBs tested binds TTR in plasma. Some of the OH-PCBs displace thyroid hormone (T4) from TTR, rationalizing the toxicity observed in rodents, where TTR is the major T4 transporter. Thyroid binding globulin and albumin are the major T4 carriers in humans, making it unlikely that enough T4 could be displaced from TTR to be toxic. OH-PCBs are excellent TTR amyloidogenesis inhibitors in vitro because they bind to the TTR tetramer, imparting kinetic stability under amyloidogenic denaturing conditions. Four OH-PCB/TTR cocrystal structures provide further insight into inhibitor binding interactions. 相似文献
132.
Solvent extraction of chromium(VI) ion associates with symmetric cyanine dyes including the heterocyclic radicals of 1,3,3-trimethyl-3N-indoline, benzooxazol, benzothiazol and quinoline has been studied by means of spectrophotometric method. In the acidic medium in the presence of chloride ions, extractable by aromatic hydrocarbons and esters of acetic acids, chromium(VI) ion associates are formed. The molar absorptivities of ion associates are 2.5-3.6x10(5) l mol(-1) cm(-1) in dependence on extractant and dye. The absorbance of the coloured extracts obeys the Beer's law in the range 0.01-2.1 mg l(-1). The extraction of chromium is the highest during extraction from the sulphuric acid medium in the range 0.05-03 M H(2)SO(4). It was found that the Cr(VI):Cl:R molar ratio is 1:1:1. A novel procedure of chromium(VI) extraction and spectrophotometric determination in various types of soils and sewage doped with chromium(VI) was examined. 相似文献
133.
Microwave-assisted synthesis utilizing supported reagents: a rapid and efficient acylation procedure
[reaction: see text] The application of microwave heating to a polymer-assisted solution-phase (PASP) synthesis technique has been utilized to develop a rapid and efficient protocol for the solution-phase synthesis of amides from either amine or carboxylic acid cores. 相似文献
134.
135.
Nacke T Brückner K Göller A Kaufhold S Nakos X Noack S Stöber H Beckmann D 《Analytical and bioanalytical chemistry》2005,383(5):752-757
Dry substances (DS) are an important index for monitoring and controlling anaerobic co-digestion in biogas plants. We have
developed and tested an online meter that measures suspended solids by means of the reflection coefficient of an exiting microwave
signal, which is dependent on the dielectric properties of the suspensions. Intelligent models based on partial least squares
regression (PLSR) and artificial neural network (ANN) for calibration allow exact and reproducible measurements under different
circumstances. This measuring method is appropriate for contactless and online measurements of dry substance contents in biogas
plants in a large range from 2–14%. 相似文献
136.
Trimethylsilyl chloride elimination reactions have been well documented. We now report the use of trimethylsilyl acetate elimination reaction in the preparation of binary alloys, HgTe and CdTe. The new compound, (MeHg)3P, and the known compound (MeHg)2S have been prepared by the trimethylsilyl acetate elimination reaction and characterized by NMR spectroscopy, electron ionization mass spectroscopy, and elemental analysis. 相似文献
137.
138.
Tom Desmet Marc Claeyssens Kathleen Piens Wim Nerinckx 《Journal of carbohydrate chemistry》2013,32(4):164-180
The cellulase mixture of Hypocrea jecorina (formerly Trichoderma reesei) contains a variety of exo- and endoglucanases that belong to different structural families. As such, these enzymes form an interesting model system to study the enzyme-ligand interactions in glycoside hydrolases. The nucleophilic carboxylate of retaining β-glycosidases is believed to form a hydrogen bond with the 2-hydroxyl group of their substrate. Consequently, replacing this hydroxyl group with an amino group should result in a stronger electrostatic interaction and thus an increased affinity for the ligand. In this study, several modified cellobiosides were synthesized and evaluated as cellulase inhibitors. The introduction of an amino group was found to have an unpredictable effect on the inhibitory power of the ligands. However, the enzymes display a very high affinity for the corresponding 2-azido compounds, precursors in the synthetic route. The new ligand m-iodobenzyl 2-deoxy-2-azido-β-cellobioside even is the strongest inhibitor of cellobiohydrolase I known to date (KI = 1 μM). 相似文献
139.
140.
Structural Chemistry - The newly measured ionization potential of atomic astatine is discussed and compared with that of the recently determined value for polonium and for the other atomic... 相似文献