排序方式: 共有96条查询结果,搜索用时 46 毫秒
41.
This study reports the fabrication of an amperometric cholesterol biosensor based on cholesterol oxidase (ChOx), SnO2NPs and Nafion-modified carbon paste enzyme electrodes (CPE/SnO2NPs-ChOx/Naf). The electrochemical characterisations of BCPE and CPE/SnO2NPs were performed using CV and EIS. The determination of cholesterol was carried out by electrochemical oxidation of H2O2 at 0.6 V vs. Ag/AgCl. The CPE/SnO2NPs-ChOx/Naf presented a linear range from 0.20 μ.mol L?1 to 4.95 μmol L?1 with a low limit of detection (0.04 μ.mol L?1). In addition, the optimal values for pH and temperature were found to be 7.5 and 35°C, respectively. The CPE/SnO2NPs-ChOx/Naf was used for the determination of cholesterol in serum samples and good results were obtained. 相似文献
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Derya Gülcemal Milena Masullo Ozgen Alankuş‐Çalışkan Tamer Karayıldırım Serdar G. Şenol Sonia Piacente Erdal Bedir 《Magnetic resonance in chemistry : MRC》2010,48(3):239-243
A new secondary metabolite, pterocephaline, along with the known cantleyoside, 7α‐morroniside, 3β,5α‐tetrahydrodesoxycordifoline lactam, 5S‐5‐carboxyvincoside, sweroside, and loganin have been isolated from the aerial parts of P. pinardii (Dipsacaceae). Moreover, cantleyoside‐methyl‐hemiacetal and cantleyoside‐dimethyl‐acetal were obtained as seco‐iridoid artifacts. The structures were elucidated by extensive spectroscopic methods including 1D‐(1H, 13C and TOCSY) and 2D‐NMR (DQF‐COSY, HSQC and HMBC). Monoterpenoid glucoindole alkaloids were encountered for the first time in Dipsacaceae family. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
44.
Herzer N Guneysu H Davies DJ Yildirim D Vaccaro AR Broer DJ Bastiaansen CW Schenning AP 《Journal of the American Chemical Society》2012,134(18):7608-7611
A printable H-bonded cholesteric liquid crystal (CLC) polymer film has been fabricated that, after conversion to a hygroscopic polymer salt film, responds to temperature and humidity by changing its reflection color. Fast-responding humidity sensors have been made in which the reflection color changes between green and yellow depending on the relative humidity. The change in reflection band is a result of a change in helix pitch in the film due to absorption and desorption of water, resulting in swelling/deswelling of the film material. When the polymer salt was saturated with water, a red-reflecting film was obtained that can potentially act as a time/temperature integrator. Finally, the films were printed on a foil, showing the potential application of supramolecular CLC materials as low-cost, printable, battery-free optical sensors. 相似文献
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Melis Ulu Dog?ru Neriman Varl?kl? Derya Baykal Güliz K?y Dog?ukan Ta?er Halife ?ag?lar Emine Gündüz 《International Journal of Theoretical Physics》2012,51(5):1545-1554
In this paper, we devote to investigate the energy-momentum problem of higher dimensional black holes in the general theory
of relativity. The energy and momentum complex of M?ller has been used for the calculations. Also, total energy and total
momentum of some special cases for higher dimensional black holes such as Schwarzschild-like black holes, Reissner-Nordstr?m-like
charged black holes, AdS-like black holes, topological black holes, BTZ-like and charged BTZ-like black holes were obtained.
It is invented that the momentum of black holes vanishes everywhere while the energy of black holes are not equal to zero
in higher dimension. Also the results agree with Yang and Radinschi or Vagenas results in three and four dimensional black
holes, respectively (Jang and Radinschi in AIP Conf. Proc. 895, 325, 2007; Vagenas in Mod. Phys. Lett. A 21, 1947, 2006). 相似文献
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XAD copolymer resins may be functionalized with heavy metal ion-selective ligands either by covalent linkage to the polymer backbone or by impregnation. These resins may be tailored to be specific for certain heavy metals by adjusting the retention and elution parameters. For the synthesis of immobilized Amberlite XAD-4 copolymer resins that are expected to preconcentrate a number of transition and heavy metals, the Schiff base method was chosen. For this purpose the copolymer was nitrated, reduced to the corresponding amine and converted to the imine compounds via a Schiff base reaction using different organic aldehyde compounds. The interactions of 8 elements (Cd, Co, Cu, Mn, Ni, Pb, U and Zn) with the resins were qualitatively investigated. Optimal pH for retention was typically 6-8 for most resins although one could be used at pH 5 and elution was achieved using 0.1 M HNO3. The resins were characterized by FTIR, SEM and elemental analysis. It was demonstrated that the resins could be used to preconcentrate ultra-trace analytes from natural waters, and analysis of environmental certified reference materials using FI-ICP-MS showed good agreement with the certified values. Metal retention capacities were also calculated using a batch system and were found to compare favorably with other resins reported in the literature. 相似文献
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Ulviye Acar Çevik Derya Osmaniye Begüm N. Sağlik Serkan Levent Betül K. Çavuşoğlu Abdullah B. Karaduman Ümide D. Özkay Yusuf Özkay Zafer A. Kaplancikli Gülhan Turan 《Journal of heterocyclic chemistry》2020,57(5):2225-2233
Monoamine oxidases (MAO) are enzymes that catalyze the oxidative deamination of monoamines such as dopamine, noradrenaline, adrenaline, and serotonin. Recent studies have shown that numerous benzothiazole derivatives exhibit hMAO inhibitory activity in the micromolar concentration range. In this study, a novel series of benzothiazole-thiadiazole (5a-5l ) was synthesized and characterized their chemical structures by 1H-NMR, 13C-NMR, and Mass spectroscopy. These compounds were evaluated as inhibitors for types A and B MAO enzymes. Compounds 5f and 5l were the most active derivatives in the series with an IC50 values of 0.107 ± 0.003 and 0.128 ± 0.004, respectively. Furthermore, cytotoxicity of compounds 5f and 5l were investigated and found as non-cytotoxic. 相似文献
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Ayşegül Karaküçük-İyidoğan Zeliha Mercan Emine Elçin Oruç-Emre Demet Taşdemir Derya İşler İbrahim Halil Kılıç 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):661-673
Abstract The synthesis and characterization of 18 novel thiosemicarbazones have been investigated as part of a research program on development of compounds with antibacterial and antioxidant activities. Among the tested compounds, 2-(4-hydroxybenzylidene)-N-[4-(trifluoromethoxy)phenyl]hydrazine carbothioamide (3g) and 2-(thiophen-2-ylmethylidene)-N-[4-(morpholin-4-yl)phenyl]hydrazine carbothioamide (4b) showed excellent inhibition potency at low concentration (0.5 μg/mL) against Gram-positive pathogens (Enterococcus faecalis and Staphylococcus aureus). All tested compounds were also found to possess antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.] 相似文献
50.
The reactions of cyclotriphosphazene, N3P3Cl6 (1), in a 1:1.2 stoichiometry with the sodium derivative of seven diols [ethane- (2a), 1,3-propane- (2b), 1,4-butane- (2c), 1,5-pentane- (2d), 1,6-hexane- (2e), 1,8-octane- (2f) and 1,10-decane- (2g) diol] in THF solution at room temperature have been used to investigate the effect of chain length on the formation of reaction products. Although no new products were found for the reaction of 1 with diols 2a-c compared to those in the literature using other bases and solution conditions, the reactions of 1 with the diols 2d-g gave six different types of products, whose structures have been characterized by elemental analysis, mass spectrometry, 1H and 31P NMR spectroscopy; ansa compounds N3P3Cl4[O(CH2)nO], (5d-5g); single-bridged compounds N3P3Cl5[O(CH2)nO]N3P3Cl5(6d-6f); double-bridged compounds N3P3Cl4[O(CH2)nO]2N3P3Cl4 (7d-7g, syn and anti) and triple-bridged compounds, N3P3Cl3[O(CH2)nO]3N3P3Cl3 (8d-f). Where suitable single crystals were obtained, X-ray crystallographic studies confirmed the structures of two ansa compounds (5d and 5f), one single-bridged compound (6e), and five double-bridged compounds (meso-anti for 7d, 7e, 7f and meso-syn for 7d and 7f). 31P NMR measurements of the reaction mixtures were used to quantify the formation of products for the reactions 1 with all the diols, 2a-g; it is found that, with increasing chain length of the diol, there is a decrease in the products formed by intramolecular reactions (spiro and ansa derivatives) and a concomitant increase in the amounts of products formed by intermolecular reactions (single-, double- and triple-bridged derivatives) of cyclophosphazene. 相似文献