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101.
Asra S. Razavian Sayed M. Ghoreishi Amir S. Esmaeily Mohsen Behpour Lorena M. A. Monzon J. Michael D. Coey 《Mikrochimica acta》2014,181(15-16):1947-1955
An electrochemical sensor was developed and tested for detection of L-tyrosine in the presence of epinephrine by surface modification of a glassy carbon electrode (GCE) with Nafion and cerium dioxide nanoparticles. Fabrication parameters of a surfactant-assisted precipitation method were optimized to produce 2–3 nm CeO2 nanoparticles with very high surface-to-volume ratio. The resulting nanocrystals were characterized structurally and morphologically by X-ray diffractometery (XRD), scanning and high resolution transmission electron microscopy (SEM and HR-TEM). The nanopowder is sonochemically dispersed in a Nafion solution which is then used to modify the surface of a GCE electrode. The electrochemical activity of L-tyrosine and epinephrine was investigated using both a Nafion-CeO2 coated and a bare GCE. The modified electrode exhibits a significant electrochemical oxidation effect of L-tyrosine in a 0.2 M Britton-Robinson (B-R) buffer solution of pH 2. The electro-oxidation peak current increases linearly with the L-tyrosine concentration in the molar concentration range of 2 to 160 μM. By employing differential pulse voltammetry (DPV) for simultaneous measurements, we detected two reproducible peaks for L-tyrosine and epinephrine in the same solution with a peak separation of about 443 mV. The detection limit of the sensor (signal to noise ratio of 3) for L-tyrosine is ~90 nM and the sensitivity is 0.20 μA μM?1, while for epinephrine these values are ~60 nM and 0.19 μA μM?1. The sensor exhibited excellent selectivity, sensitivity, reproducibility and stability as well as a very good recovery time in real human blood serum samples.
102.
This paper presents a combination of the hybrid spectral collocation technique and the spectral homotopy analysis method(SHAM for short) for solving the nonlinear boundary value problem(BVP for short) for the electrohydrodynamic flow of a fluid in an ion drag configuration in a circular cylindrical conduit. The accuracy of the present solution is found to be in excellent agreement with the previously published solution. The authors use an averaged residual error to find the optimal convergence-control parameters. Comparisons are made between SHAM generated results, results from literature and Matlab ode45 generated results, and good agreement is observed. 相似文献
103.
Proton NMR was used to study the complexation reaction of Li+ and Na+ ions with 15-Crown-5 (15C5) in a number of binary acetonitrile (AN)-nitrobenzene (NB) mixtures at different temperatures. In all cases, the exchange between free and complexed 15C5 was fast on the NMR timescale and only a single population average 1H signal was observed. The formation constants of the resulting 1:1 complexes in different solvent mixtures were determined by computer fitting of the chemical shift mole ratio data. There is an inverse relationship between the complex stability and the amount of AN in the solvent mixtures. The enthalpy and entropy values for the complexation reaction were evaluated from the temperature dependence of the formation constants. In all the solvent mixtures studied, the resulting complex is enthalpy stabilized but entropy destabilized. Finally, the experimental results were compared with theoretical ones that were obtained from molecular modeling methods. Based on our results, it is most probable that Li+-15C5 in solvent stays in a rather nesting complex form with greater LogKf values, but Na+-15C5 forms a complete perching complex form with lower LogKf values. 相似文献
104.
Amir Khojastehnezhad Abolghasem Davoodnia Mehdi Bakavoli Niloofar Tavakoli‐Hoseini Mohsen Zeinali‐Dastmalbaf 《中国化学》2011,29(2):297-302
A simple, efficient and green method for the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes by a one‐pot condensation reaction of β‐naphthol and aryl aldehydes using silica gel‐supported polyphosphoric acid (PPA/SiO2), an effective and reusable catalyst, under solvent‐free conditions is described. The present methodology offers several advantages, such as a simple procedure with an easy work‐up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents. 相似文献
105.
Shahlaei M Madadkar-Sobhani A Fassihi A Saghaie L 《Journal of chemical information and modeling》2011,51(10):2717-2730
The seven transmembrane helices G-protein-coupled receptors (GPCRs) form one of the largest superfamilies of signaling proteins found in humans. Homology modeling, molecular docking, and molecular dynamics (MD) simulation were carried out to construct a reliable model for CCR1 as one of the GPCRs and to explore the structural features and the binding mechanism of BX471 as one of the most potent CCR1 inhibitors. In this study, BX471 has been docked into the active site of the CCR1 protein. After docking, one 20 ns MD simulation was performed on the CCR1-ligand complex to explore effects of the presence of lipid membrane in the vicinity of the CCR1-ligand complex. At the end of the MD simulation, a change in the position and orientation of the ligand in the binding site was observed. This important observation indicated that the application of MD simulation after docking of ligands is useful. Explorative runs of molecular dynamics simulation on the receptor-ligand complex revealed that except for Phe85, Phe112, Tyr113, and Ile259, the rest of the residues in the active site determined by docking are changed. The results obtained are in good agreement with most of the experimental data reported by others. Our results show that molecular modeling and rational drug design for chemokine targets is a possible approach. 相似文献
106.
A novel four-component reaction between 2-formylbenzoic acids, malononitrile, isocyanides, and alcohols has been developed for a highly efficient preparation of alkyl-2-(1-(alkylcarbamoyl)-2,2-dicyanoethyl)benzoate derivatives. This high atom economy reaction led to the construction of two carbon-carbon bonds, one amide, and one ester group in a single synthetic step. Furthermore, a three-component reaction between 2-formylbenzoic acids, malononitrile, and isocyanides in dichloromethane for the preparation of isochromeno[3,4-b]pyrroles has been reported. 相似文献
107.
108.
A single cell passive air-breathing liquid feed direct methanol fuel cell (DMFC) is designed and fabricated. Furthermore, the effects of cell orientation and environmental conditions such as temperature and relative humidity on the performance of such passive DMFC are tested experimentally. The obtained results indicate that both environmental temperature and relative humidity have significant effects on the performance of fabricated fuel cell. The experimental data contained within this work shows that under lower relative humidity and higher temperature, the passive air-breathing direct methanol fuel cell has higher power output and better performance. According to experimental results, flooding has a vital role on the cell performance in various relative humidity and temperatures. The results also show that cell orientation has a strong effect on the performance of passive DMFC. The best power output and performance were achieved under vertical orientation. 相似文献
109.
Seyyed Mojtaba Mousavi Seyyed Alireza Hashemi Masoomeh Yari Kalashgrani Ahmad Gholami Yousef Mazaheri Mohsen Riazi Darwin Kurniawan Mohammad Arjmand O. Madkhali Mahmood D. Aljabri Mohammed M. Rahman Wei-Hung Chiang 《Chemical record (New York, N.Y.)》2024,24(1):e202200266
The ever-growing demand of human society for clean and reliable energy sources spurred a substantial academic interest in exploring the potential of biological resources for developing energy generation and storage systems. As a result, alternative energy sources are needed in populous developing countries to compensate for energy deficits in an environmentally sustainable manner. This review aims to evaluate and summarize the recent progress in bio-based polymer composites (PCs) for energy generation and storage. The articulated review provides an overview of energy storage systems, e. g., supercapacitors and batteries, and discusses the future possibilities of various solar cells (SCs), using both past research progress and possible future developments as a basis for discussion. These studies examine systematic and sequential advances in different generations of SCs. Developing novel PCs that are efficient, stable, and cost-effective is of utmost importance. In addition, the current state of high-performance equipment for each of the technologies is evaluated in detail. We also discuss the prospects, future trends, and opportunities regarding using bioresources for energy generation and storage, as well as the development of low-cost and efficient PCs for SCs. 相似文献
110.
Mohsen Shenasa Sudhakar Sainkar David Lichtman 《Journal of Electron Spectroscopy and Related Phenomena》1986,40(4):329-337
X-ray photoelectron spectroscopy (XPS) of the Se 3d peak for Se in Se, SeO2, As2Se3, ZnSe, CdSe, CoSe, FeSe, CrSe, VSe2 and TiSe were studied. It was found that, firstly, in the case of As2Se3, ZnSe, CdSe, CoSe and CrSe, as the change in electronegativity of the anion increases, the change in the binding energy value of the Se 3d peak also increases and, secondly, in all of the Se compounds studied, the Se-Se bond in pure Se is stronger than the Se-x bond, where X = As, Zn, Cd, Co, Fe, Cr, V and Ti. 相似文献