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Streubel R Schiemann U Jones PG Tran Huy NH Mathey F 《Angewandte Chemie (International ed. in English)》2000,39(20):3686-3688
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Background
Genetically manipulated embryonic stem (ES) cell derived neurons (ESNs) provide a powerful system with which to study the consequences of gene manipulation in mature, synaptically connected neurons in vitro. Here we report a study of focal adhesion kinase (FAK), which has been implicated in synapse formation and regulation of ion channels, using the ESN system to circumvent the embryonic lethality of homozygous FAK mutant mice. 相似文献5.
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Simultaneous speciation of mixed standard solutions of triphenyltin halides (triphenyltin chloride, bromide, iodide) and pseudohalide (triphenyltin isothiocyanate) has been achieved with reversed‐phase high‐performance liquid chromatography on a Waters Spherisorb S5W ODS‐2 (octadecyl‐silica) column. An isocratic mixture of 95:5 (v/v) acetonitrile:water was used as the mobile phase at a flow rate of 1 ml min?1. A series of selected triphenyltin carboxylates, Ph3SnOCOZ, where Z = Me, Ph, CH:CHPh, CH:NOMe, CH2SC5H4N and CH2SC(S)NMe2, was also similarly analysed using this system with two separate isocratic elutions using 100% acetonitrile and 96:4 (v/v) acetonitrile:water as the mobile phase. UV detection was done at 254 nm and the total run time for each analysis was less than 3 min. The detection limits for all the phenyltin(IV) compounds were in the range 0.01–0.03 ppm. Spiked water samples containing the triphenyltin carboxylates could also be simultaneously analysed by the above method without the need for any prior derivatization, following extraction with hexane. Pretreatment of the aqueous sample with NaCl/HCl and of the organic phase with hexamethylphosphoramide enabled recoveries of about 80% of the triphenyltins. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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A rapid speciation high‐performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of phenyltin compounds. The commercially important products of triphenyltin‐chloride, ‐acetate, ‐hydroxide and tetraphenyltin were separated by reversed‐phase HPLC on a Waters Spherisorb S5W ODS‐2 (octadecylsilica) column using an isocratic mixture of 90:10 (v/v) acetonitrile:water as the mobile phase at a flow rate of 1 ml min?1. The phenyltin compounds were detected by UV detection at 254 nm and the total elution time is 8 min. The elution order is triphenyltin‐chloride, ‐acetate, ‐hydroxide and tetraphenyltin. Detection limits were 0.01 ppm for each of the triphenyltin compounds and 0.02 ppm for tetraphenyltin. Spiked water samples containing the three biocidal triphenyltin compounds could also be analysed simultaneously by the above method without the need for any prior derivatization, following extraction with toluene. The versatility of the method in sensing substituent group variations on the phenyl ring was also demonstrated by the successful resolution of the hydroxides, tris(p‐chlorophenyl)tin hydroxide, diphenyl(p‐chlorophenyl)tin hydroxide and triphenyltin hydroxide. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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The determination of low concentrations of arsenic in glycerine is investigated with flow injection for the introduction of analyte and tetrahydroborate reagent for arsine generation, separation in a vapor-liquid flow cell, and inductively-coupled plasma/atomic emission spectrometry (i.c.p./a.e.s.). Peak areas are used to quantify arsenic in the concentration range 0.12–3.0 μg ml?1. Peak areas for prepared standards exhibited average deviations of about 1.4% for this concentration range. The slope and intercept for a least- squares fit of area (nanocoulombs) vs. concentration (μg ml?1) were 10.9 ± 0.17 and 0.46 ± 0.3, respectively. 相似文献
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Measurements by fluoride ion-selective electrode potentiometry on the very weak monofluoride complexes of the alkali metal ions in aqueous solution at 25°C and an ionic strength of 1M indicate their stability constants lie in the order Li+ > Na+ > K+ > Rb+ ? Cs+. Data at varying ionic strengths and temperatures were used to calculate infinite dilution stability constants and enthalpies and entropies of complexation for LiF and NaF. 相似文献