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11.
Iman Manavi-Tehrani Mohammad Rabiee Maryam Parviz Mohammad Reza Tahriri Zahra Fahimi 《Macromolecular Symposia》2010,296(1):457-465
In the present research hydrogel films based on polyvinyl alcohol (PVA) and polyacrylic acid (PAA) blend, with various crosslink densities, have been prepared through different thermal treatment. The results of FTIR and DSC confirmed quality and quantity of conclusion on miscibility of PVA/PAA blends, respectively. Besides, biocompatibility of the samples has been proved in cytotoxicity tests using L929 cells, according to ISO10993–5. Water uptake of the hydrogel blends is measured. pH sensitivity properties of blends are studied with and without boiling in NaOH solutions where the effect of swelling in water before boiling has also been investigated. Preswellings in water and NaOH concentration have been found to be mainly effective on pH sensitivity of PVA/PAA blends. Biocompatibility and pH sensitivity behavior make these hydrogels appropriate candidates to orally deliver drugs such as insulin and peptides that can be released in basic pH of intestine. The stability of these films in acidic solutions and its expansion and also the consequent release of drugs in basic solutions have been studied by using Teofilin as a model drug by UV-spectrophotometeric measurements. 相似文献
12.
Javanbakht M Badiei A Ganjali MR Norouzi P Hasheminasab A Abdouss M 《Analytica chimica acta》2007,601(2):172-182
A new functionalized nanoporous silica gel with dipyridyl group (DPNSG) was synthesized. Then, the potentiometric response of the copper(II) ion was investigated at a carbon paste electrode chemically modified with this newly designed functionalized nanoporous silica gel. The electrodes with DPNSG proportions of 15.0% (w/w) demonstrated very stable potentials. Calibration plots with Nernstian slopes for Cu2+ were observed, 28.4 (±1.0) mV decade−1, over a wide linear concentration range (1.0 × 10−7 to 1.0 × 10−2 M). The electrode exhibited a detection limit of 8.0 × 10−8 M. Moreover, the selectivity coefficients measured by the match potential method in acetate buffer, pH 5.5, were investigated. The electrode presented a response time of ∼50 s, high performance, high sensitivity in a wide range of cation activities and good long-term stability (more than 9 months). The method was satisfactory and was used to determine the copper ion concentration in waste waters, contaminated by this metal. 相似文献
13.
Mohammad H. Alizadeh Toktam Kermani Reza Tayebee 《Monatshefte für Chemie / Chemical Monthly》2007,138(2):165-170
Summary. Esterifications of acetic acid with some linear, secondary, tertiary, and benzylic alcohols mediated by catalytic amounts
of Keggin, Wells–Dawson, and Preyssler type heteropolyacids were carried out under reflux at mild reaction conditions with good to excellent yields. Among the examined
catalysts, H3PW12O40 and H14NaP5W30O110 revealed better results than other heteropolyacids. This work was performed with the aim of simplifying the esterification
process by omitting any solvents and mineral acid catalysts. Easy work-up, low cost, and acidic waste reduction, which are
all important features from the environmental and economical points of view, are distinct aspects of this protocol. Heteropolyacid
catalysts could be separated after a simple work-up and reused for several times. 相似文献
14.
15.
Ali Asghar Hatamnia Arman Rostamzad Parviz Malekzadeh Reza Darvishzadeh Nasser Abbaspour Mohammadyar Hosseini 《Natural product research》2016,30(12):1445-1450
The fruits of Pistacia khinjuk Stocks were collected from Ilam province, Iran. The aim of this study was to analyse antioxidant capacity and phenolic composition of different parts of P. khinjuk fruit. The antioxidant capacity of extracts was measured using different assays: ferric reducing ability of plasma, 2,2-diphenyl-1-picrylhydrazyl and nitric oxide radical scavenging. The phenolic composition of P. khinjuk fruit is reported for the first time. Amongst different parts of the fruit analysed in this study, hull extract contained the highest total phenolic and flavonoid contents. We observed a high correlation between different antioxidant activity and total phenolic and flavonoid contents. Therefore, antioxidant capacity can be related to total phenolic and flavonoid contents. A correlation analysis revealed that ascorbic acid, gallic acid, rutin, caffeic acid, ferulic acid and sinapic acid were the phenolic compounds mainly responsible for antioxidant power of the fruit extracts. 相似文献
16.
In this paper, an improved recovery method for target ssDNA using amino-modified silica-coated magnetic nanoparticles (ASMNPs) is reported. This method takes advantages of the amino-modified silica-coated magnetic nanoparticles prepared using water-in-oil microemulsion technique, which employs amino-modified silica as the shell and iron oxide as the core of the magnetic nanoparticles. The nanoparticles have a silica surface with amino groups and can be conjugated with any desired bio-molecules through many existing amino group chemistry. In this research, a linear DNA probe was immobilized onto nanoparticles through streptavidin conjugation using covalent bonds. A target ssDNA(I) (5′-TMR-CGCATAGGGCCTCGTGATAC-3′) has been successfully recovered from a crude sample under a magnet field through their special recognition and hybridization. A designed ssDNA fragment of severe acute respiratory syndrome (SARS) virus at a much lower concentration than the target ssDNA(I) was also recovered with high efficiency and good selectivity. 相似文献
17.
Tahereh Sadeghcheh Mohammad Saber Tehrani Hakim Faraji Parviz Aberoomand Azar Masoumeh Helalizadeh 《Journal of separation science》2022,45(7):1362-1373
A sensitive method based on liquid chromatography combined with a diode array detector was developed and validated to simultaneously determine tamoxifen, and its active metabolites N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen in human plasma samples. The green and sustainable vortex-assisted dispersive liquid-phase microextraction technique based on the natural hydrophobic deep eutectic solvent was used for the extraction and preconcentration of the analytes. Chemometrics and multivariate analysis were used to optimize the independent variables including the type and volume of deep eutectic solvent, extraction time, and ionic strength. Under optimal conditions, calibration curves were linear in a suitable range with the lower limits of quantification (0.8–10.0 μg/L), which covered the relevant concentrations of the analytes in plasma samples for a clinical study. Intra- and interday precision evaluated at three concentrations for the analytes were lower than 8.2 and 12.1%, respectively. Accuracy was in the range of 94.9–104.7%. The applicability of the developed method on human plasma samples illustrated the range 45.1–72.8, 98.4–128.3, 0.9–1.2, and 2.7–6.1 μg/L for tamoxifen, N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen, respectively. The validated method can be effective for the pharmacokinetics, pharmacodynamics, and therapeutic drug monitoring studies of tamoxifen and its main metabolites in biological fluids. 相似文献
18.
Movlaee Kaveh Beitollahi Hadi Ganjali Mohammad Reza Norouzi Parviz 《Mikrochimica acta》2017,184(9):3281-3289
Microchimica Acta - A carbon paste electrode (CPE) was modified with graphene and ethyl 2-(4-ferrocenyl-[1,2,3]triazol-1-yl) acetate (EFTA) and used for electrocatalytic oxidation of levodopa.... 相似文献
19.
Naader Alizadeh Mahsa Amiri Fariba Mohammadpour Parviz Norouzi 《Electroanalysis》2023,35(10):e202300114
This research represents a novel detection method of acetone level in the exhaled breath samples (RH=88 %) based on polypyrrole/tungsten oxide (PPy/WO3) nanocomposite sensor. The PPy/WO3 sensor was fabricated by the deposition of nanocomposite on/between interdigitated electrodes (IDEs) through electrospray coating and was then characterized by FE-SEM imaging. In this detection method, the coulometric signal of the sensor was calculated using Fast Fourier Continuous Cyclic Voltammetry (FFTCCV), where cyclic voltammetry (CV) was applied to the sensor in the defined potential rang and then charge changes of the sensor was obtained by integration of the current in all scanned potential ranges. FFTCCV method enhances the sensitivity of the sensor when exposed to the gas mixtures containing acetone. In addition to its fast coulometric response time (≤5 s) in the two linear ranges of 0.7–2.8 ppm and 2.8–28.2 ppm (R2=0.99), FFTCCV method provides the low detection limit of 70 ppb, and high sensitivity toward acetone at the optimum values of the parameters. The fabricated sensor showed great selectivity toward acetone when exposed to humid air and some exhaled gas like carbon dioxide, ammonia, methanol, ethanol and alkyl amines. The results were very satisfying as the sensor was capable to detect different acetone levels in human exhaled breath as non-invasive diagnosis of diabetes with a good correlation (R2≃0.9) to the routine blood sugar test taken by different commercial glucometers results. 相似文献
20.
Guest Editorial: Wireless Mobile Internet 总被引:1,自引:0,他引:1