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121.
122.
İbrahim Erol Levent Özcan Sedat Yurdakal 《Journal of Thermal Analysis and Calorimetry》2013,114(1):377-385
The derivatives of styrene monomer, 4-chlorophenyl-4-vinylbenzyl ether (M1), 4-methoxyphenyl-4-vinylbenzyl ether (M2), 4-ethylphenyl-4-vinylbenzyl ether (M3) and 1-naphtylphenyl-4-vinylbenzyl ether (M4) were synthesized. The normal free radical polymerization of monomers in 1,4-dioxane were performed by using 2,2′-azobisisobutyronitrile as an initiator at 65 °C. The monomers and their homopolymers were characterized by FT-IR, NMR and elemental analyses measurements. The thermal stability of polymers was investigated by thermogravimetric and differential scanning calorimetric analysis. Thermal degradation activation energies of the polymers were calculated by the Ozawa and Kissinger methods. In addition, photo-stability tests of the polymers under near-UV irradiation were performed. 相似文献
123.
Sonochemical synthesis and electrochemical characterization of α-nickel hydroxide: precursor effects
F. Sinem Ertaş Recep Kaş Uğur Ünal Özgür Birer 《Journal of Solid State Electrochemistry》2013,17(5):1455-1462
Sonochemical degradation of urea was employed to synthesize alpha-nickel hydroxide from different nickel salts. Utilization of ultrasound yielded products with properties significantly different than the products obtained by thermal degradation of urea. The effect of intercalating chloride, nitrate, acetate, and sulfate anions on morphology and electrochemical performance was studied. The sulfate-intercalated sample had the smallest interlayer spacing when obtained by the sonochemical method, contradicting all the previous thermal synthesis results. The specific capacitance trend also differed from the literature values, and the value for the sulfate-intercalated sample was larger than that of acetate- and nitrate-intercalated samples. Ultrasonic synthesis increased the specific capacitance of the sulfate-intercalated sample significantly. This sample was also the most reversible and had the highest charge efficiency. 相似文献
124.
The interaction of cysteine (RSH) with a thiazide diuretic, hydrochlorothiazide (HCTZ) was characterized by UV-Vis absorption spectroscopy and square-wave voltammetry in Britton-Robinson (B-R) buffer solution (with pH 5, 7 and 9). On the square-wave voltamogram of cysteine, the reduction peak current of mercurous cysteine thiolate (Hg2(RS)2) decreased and its peak potential shifted to more positive values with the addition of HCTZ. This results showed that the RSH interacted with HCTZ. The stoichiometry of HCTZ-RSH molecular complex was determined by voltammetric data with the result of 1: 1. By using linear regression analysis of the voltammetric data at pH 5, 7 and 9, the apparent formation constants of HCTZ-RSH complex were calculated to be 9.54 × 103, 2.80 × 104 and 2.55 × 104 M?1, respectively. At the same time, this interaction was also supported by UV-Vis spectroscopic measurements. According to the voltammetric and spectroscopic results, it was suggested that the interaction mode between RSH and HCTZ molecules might be a combination of hydrophobic interactions and hydrogen bonds. 相似文献
125.
O. O. Soldatkin I. S. Kucherenko M. K. Shelyakina E. Soy K. Kirdeciler S. Öztürk N. Jaffrezic‐Renault B. Akata S. V. Dzyadevych A. P. Soldatkin 《Electroanalysis》2013,25(2):468-474
Different modifications of the zeolites Na+‐Beta and LTA were applied for improving the working characteristics of a urea biosensor. The bioselective membrane of the biosensor was based on urease and different zeolites co‐immobilized with bovine serum albumin on the surface of a pH‐FET. It was shown that the biosensors modified with the zeolites H+‐Beta30 and H+‐Beta50 are characterized by increased sensitivity to urea. The influence of the zeolite concentration on the sensitivity of the biosensors was studied. The optimal concentration of the zeolites H+‐Beta30 and H+‐Beta50 in the bioselective membrane was 15 %. Different variants of co‐immobilization of urease and zeolite H+‐Beta30 were studied and the optimal method was selected. Thus, a general conclusion is that the urea biosensor sensitivity can be improved using zeolite H+‐Beta30 for urease immobilization in the bioselective membrane. 相似文献
126.
Ayşegül Doğan Emirhan Nemutlu M. Aykut Özek Hakan Eroğlu Sedef Kır M. Sinan Beksaç 《Chromatographia》2013,76(21-22):1513-1519
Pregnancy alters pharmacokinetic profile of many drugs, because of altering body volume and metabolism rate. Therefore, dosage rates and concentrations of drugs must be controlled during pregnancy. Here, we identified the pharmacokinetic profile of pre-operatively given cefepime in caesarean section and gynecological operations using a simple, rapid, cost-effective and valid liquid chromatographic method. The chromatographic separation was performed using 40 mM, pH 3.2 phosphate buffer containing 6 % methanol as mobile phase at 0.30 mL min?1 flow rate. Gradient elution with methanol was applied to get shorter analysis time without any interference from plasma endogens. During analyses, temperature of column, autosampler and detector were set as 30, 10 and 40 °C, respectively. The detection wavelength was 260 nm and ceftizoxime was used as internal standard. At the optimum conditions, the cefepime analysis from plasma samples was completed in 7 min. Cefepime was extracted from plasma samples using perchloric acid with a very high recovery rate (99.3 %). The method was fully validated according to the Food and Drug Administration guidelines for bioanalytical method validation, and found to be selective, linear, repeatable, reproducible and robust. After validation studies, the method was applied to five caesarean-sectioned and four non-pregnant sectioned women treated with pre-operative, prophylactic single intravenous dose of cefepime (1 g Maxipime®) in order to determine pharmacokinetic profile of cefepime. Peak serum concentrations of cefepime in caesarean-sectioned women at the arterial port after infusion was 70.11 ± 10.74 μg mL?1. The mean elimination half-life, volume of distribution and calculated area under the concentration–time curve (AUC)0–∞ were 1.10 ± 0.23 h, 14.22 ± 2.29 L and 101.55 ± 10.99 μg h mL?1 for caesarean-sectioned women; and 1.14 ± 0.21 h, 14.76 ± 2.92 L and 104.71 ± 36.34 μg h mL?1 for non-pregnant sectioned women, respectively. The area under curve, elimination half-life, maximum plasma concentration and the mean distribution volume of cefepime were not changed in case of pregnancy. 相似文献
127.
In this study, first, a series of chalcone compounds S1–S6 were synthesized from various acetophenone derivatives (acetophenone, p-methyl acetophenone, and p-methoxy acetophenone) and aromatic aldehyde derivatives (benzaldehyde, p-methyl benzaldehyde, and p-methoxy benzaldehyde) by the Claisen–Schmidt condensation reaction. These S1–S6 compounds were then used in the preparation of 4,5-dihydropyrazol-1-yl derivatives S7–S15. Finally, four new compounds S16–S19 were synthesized from compound (S7, S8, S9, and S12) and 2,4-dinitrophenylhydrazine. Therefore, three known and ten new heterocyclic compounds were synthesized and completely characterized using 1H NMR, 13C NMR, IR, and elemental analysis. 相似文献
128.
Dopamine, rotigotin, ladostigil, and rasagiline analogues 2-amino-4,5,6-trimethoxyindane and 1-amino-5,6,7-trimethoxyindane were synthesized starting from 5,6,7-trimethoxyindan-1-one for the first time with 34% and 45% total yields. α-Carboxylation of indanone, reduction of ketone group with Et3SiH, basic hydrolysis of ester, Curtius reaction of the acid, and addition of BnOH afforded the corresponding carbamate. Pd-C-catalyzed hydrogenolysis of carbamate and deprotonation of amine hydrochloride with NaOH gave the dopamine and rotigotin analogue 2-aminoindane. Reduction of 5,6,7-trimethoxyindan-1-one with NaBH4 afforded the alcohol, which was then converted to the azide derivative via Mitsunobu reaction with diphenylphosphoryl azide; Pd-C catalyzed hydrogenation of the azide to the amine hydrochloride and then deprotonation of the amine hydrochloride with NaOH furnished the ladostigil and rasagiline analogue 1-aminoindane. These amines and BnOH were reacted with CSI to produce sulfamoyl carbamates, which were converted to sulfamides via Pd-C-catalyzed hydrogenolysis reaction with 20% and 25% total yields. 相似文献
129.
N-Aryl-N,N-diphenacylamine dioximes were prepared by the reaction of corresponding arylamines with α-bromoacetophenone oxime in ethanol-water at room temperature. These compounds reacted with aryl isocyanates in acetonitrile to give imidazooxadiazolones 9. The probable mechanism of the reaction is discussed. 相似文献
130.
Serkan Yavuz Hamdi Özkan Gülçin Tok Ali Dişli 《Journal of heterocyclic chemistry》2013,50(6):1437-1440
The substituted pyrolidine derivatives with high stereoselectivity were obtained through cycloaddition reaction in the presence of a Lewis acid namely diethylzinc by solvent‐free grinding method. 相似文献