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排序方式: 共有3321条查询结果,搜索用时 31 毫秒
101.
Ahmad Sarakbi Zeynep AydogmusAngela Dago Dominique MertensJean-Yves Dewert Jean-Michel Kauffmann 《Analytica chimica acta》2013
Liquid chromatography coupled to a silver electrode based flow-through amperometric detector (LC-EC-Ag) was developed for the determination of aminothiols in white wines. The C18 reversed phase LC system operated in the isocratic mode at 0.7 mL min−1 and used an acidic mobile phase composed of formic acid, EDTA, sodium nitrate, sodium hydroxide, and methanol 1% (v/v) at pH 4.5. The working electrode operated at 0.08 V vs Ag/AgCl, 3 M KCl and its manual cleaning was realized once a month by smoothing on a polishing cloth. The analyzed aminothiols were resolved and eluted within 4 min, and all standard curves were linear in the range 2 × 10−7–2 × 10−5 M. The analyzed wine samples needed no preparation other than dilution with the mobile phase. The concentration of cysteine (CYS), homocysteine (HCYS), glutathione (GSH) and N-acetylcysteine (NAC) in bottled white wines, determined by the method of standard addition, was found to be in the low μM range (0.2–2 mg L−1) depending on the wine type and its age. 相似文献
102.
目的探讨经颈内静脉原位导丝法换置中心静脉长期血液透析导管在维持性血液透析(MHD)患者中的应用价值。方法选取近3年在颈内静脉留置的中心静脉长期血液透析导管因功能障碍后,并经颈内静脉原位导丝法换置长期导管,术后及每次透析后均改用尿激酶封管患者16例(原位换置组);选取同期首次经颈内静脉留置中心静脉长期血液透析导管,普通肝素封管患者20例作为对照组;分析两组患者围术期泵控血流量及随访期的反应及开存期率、次开存期率。结果围术期泵控血流量原位换置组高于对照组,有统计学差异(P<0.05);两组比较感染例次/1000导管日0.9%与1.0%,无统计学差异(P>0.05)。原位换置组围术期未发生中重度并发症,12个月开存期率81.2%、次开存期率93.8%;对照组开存期率为65%、次开存期率85%;两组比较无统计学差异(P>0.05)。结论颈内静脉原位导丝法换置中心静脉长期血液透析导管,在MHD患者中的使用是安全的、可行的。 相似文献
103.
Siyuan Li Feng Jin Mayavan Viji Hyeju Jo Jaeuk Sim Hak Sung Kim Heesoon Lee Jae-Kyung Jung 《Tetrahedron letters》2017,58(14):1417-1420
An efficient and facile two-step strategy for the synthesis of (Z)-aurone from arylacetylenes and salicyladehydes, via silver(I) nitrate mediated cyclization/oxidation in the presence of potassium carbonate has been developed. The key feature of our method was delicate cascade reaction, to provide the corresponding (Z)-aurone in high yield and good regio- and stereo selectivity. 相似文献
104.
B. Movassagh M. M. Lakouraj A. Gholami 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1507-1511
Silver carbonate supported on celite (Ag 2 CO 3 /Celite) is used as a mild heterogeneous reagent for conversion of a variety of thioamides into their corresponding amides in acetonitrile at room temperature. 相似文献
105.
Water dispersible silver nanoparticles(AgNps) were prepared using thiacalix[4]arene tetrahydrazide(TCTH) as a reducing and stabilizing agent.TCTH-AgNps were characterized by surface plasmon resonance(SPR),transmission electron microscopy(TEM) and energy dispersive X-ray(EDX).Relatively uniform 20 nm spherical particles of TCTH-AgNps were efficiently formed over a pH range of 5-9 and from 10-40 ℃.The interaction behavior of TCTH-AgNps with different amino acids was investigated using spectrophotometry and spectrofluorimetry.Among the amino acids tested,only tryptophan and histidine showed fluorescence quenching and fluorescence enhancement,respectively.The linear detection range by Stern-Volmer plot was 5 nmol/L to 0.48 μmol/L for tryptophan and 4 nmol/L to 0.54 μmol/L for histidine.TCTH-AgNps were able to effectively reduce the levels of gram-positive bacteria,gram-negative bacteria,and fungi.These properties argue for the potential use of TCTH-AgNps as detectors of histidine and tryptophan and as antibiotics. 相似文献
106.
《Journal of Coordination Chemistry》2012,65(6):539-544
Silver(I) complexes of selenones, [LAgNO3] and [AgL2]NO3 (where L is imidazolidine-2-selenone or diazinane-2-selenone and their derivatives) have been prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 107Ag) spectroscopy. An upfield shift in the C=Se resonance of selenones in 13C NMR and a downfield shift in N-H resonance in 1H NMR are consistent with selenium coordination to silver(I). In 107Ag NMR, the AgNO3signal is deshielded by 450-650 ppm on coordination to selenones. Greater upfield shifts in 13C NMR were observed for [LAgNO3] compared to [AgL2]NO3complexes, whereas the opposite trend was observed for 1H and107Ag NMR chemical shifts. 相似文献
107.
《Physics letters. A》2019,383(17):2110-2113
The electron effective mass in GaAs quantum wires has been estimated by using a full dynamical random-phase approximation to examine its properties versus spin polarization, temperature, and carrier density. A decrease of mass with spin polarization is seen. The minority mass increases with the polarization while the majority mass decreases and this behaviour is seen for all densities. A maximal enhancement of mass at moderate temperature around 25 K is also presented. These calculations show a qualitative consistence with results in two-dimensional systems and help to control the electronic transport in quantum wires. 相似文献
108.
A series of new coordination polymers bearing the [B(O–C6H4–CN)4]– anion was synthesized. Two new, one dimensional coordination frameworks of the type M[B(O–C6H4–CN)4] (M = Ag, Cu) were obtained by salt metathesis. The reactivity towards organic Lewis‐bases was studied. The reaction with bidentate ligands yielded two dimensional networks with the general formula [M(L)][B(O–C6H4–CN)4] {L = 2,2′‐bipyridine, 4,4′‐bipyridine, 1,2‐bis(pyridyl)ethane, 1,4‐diazabicyclo[2.2.2]octane}. The synthesis, properties and single crystal structure are reported. 相似文献
109.
110.
A novel reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides was performed in the presence of silver nitrate or triflate.Conjugated vinyl sulfones as dramatic products were obtained in moderate yields and with Z-selectivity.A free radical mechanism has been proposed to account for the formation of the products. 相似文献