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991.
Hadi Baharifar Ali Reza Fakhari Hakimeh Ziyadi Mohammad Ali Oghabian Amir Amani Reza Faridi-Majidi 《Journal of the Iranian Chemical Society》2014,11(1):279-284
In this work, electrophoresis was successfully used to separate three different polymer-coated magnetic iron oxide nanoparticles with similar sizes (nominally 50 nm) using high-pH borate buffer system. The coating polymers were dextran, polyethylene glycol, or carboxymethyl dextran. The results showed that the migration time of carboxymethyl dextran coated nanoparticles is the longest due to relatively more negative surface charges. Investigation of the effects of buffer concentration, pH, electric field strength and the capillary temperature, on electrophoretic properties of samples was also carried out. The results showed that pH, electric field strength and the capillary temperature had indirect relations with both of the migration time and the separation resolution of three different polymer-coated nanoparticles while the buffer concentration had a direct relation. 相似文献
992.
Narges Zohari Mohammad Hossein Keshavarz Seyed Abolfazl Seyedsadjadi 《Journal of Thermal Analysis and Calorimetry》2014,115(1):93-100
This study presents a novel relationship between electric spark sensitivity of nitroaromatic energetic compounds and their activation energies of thermal decomposition. The new correlation can help to elucidate the mechanism of initiation of energetic materials by electric spark. It can be used to predict the magnitude of electric spark sensitivity of new nitroaromatics, which is difficult to measure. The methodology assumes that electric spark sensitivity of a nitroaromatic energetic compound with general formula CaHbNcOd can be expressed as a function of its activation energy of thermal decomposition as well as optimized elemental composition and the contribution of specific molecular structural parameters. The new correlation has the root mean square and the average deviations of 1.43 and 1.17 J, respectively, for 22 nitroaromatic energetic compounds with different molecular structures. The proposed new method is also tested for eight nitroaromatic energetic compounds, which have complex molecular structures, e.g., 1,3,7,9-tetranitrophenoxazine, 2,4,6-tris(2,4,6-trinitrophenyl)-1,3,5-triazine, and 1-(2,4,6-trinitrophenyl)-5,7-dinitrobenzotriazole. 相似文献
993.
Mohammad Hayatifar Luca Bernazzani Anna Maria Raspolli Galletti 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1711-1718
Random ethylene/1-hexene copolymers with the 1-hexene content in the range from 2 to 28 mol% were produced with a novel post-metallocene catalyst and analyzed by three techniques, FTIR, 13C NMR, and DSC. The 1-hexene content and the sequence distribution in the copolymers were determined by means of FTIR-M and 13C NMR. The crystallization behavior of the copolymers was studied by DSC under dynamic and isothermal conditions; the Avrami model was used to analyze the crystallization kinetics. It was found that both the 1-hexene content and the crystallization temperature affect the relative crystallinity. The bulk crystallization rate decreases with the 1-hexene content and reduces exponentially with an increase of T c. The melting behavior of isothermally crystallized samples was also investigated and it was found that the melting temperatures of the copolymers under equilibrium conditions were related to the composition. 相似文献
994.
Mohammad Mahdi Ahari-Mostafavi Ali Sharifi Mojtaba Mirzaei Massoud Amanlou 《Journal of the Iranian Chemical Society》2014,11(4):1113-1119
The objective was to obtain new scaffold of compounds possessing anti-urease activity. For this new and simple method for the synthesis of β-aryl-β-mercapto ketone derivatives based on Michael addition of thiophenol to chalcones in an ionic liquid as a solvent was improved. The products were obtained in good to moderate yields with high purity and characterized by spectral and elemental analyses. The activities of synthesized compounds were investigated as new inhibitors of jack bean urease. Among 22 synthesized compounds, all of them have shown inhibitory effect in micromolar range, and the most potent one has IC50 = 6 μM compared to hydroxyurea IC50 = 100 μM as a reference inhibitor. A docking study was performed using Autodock 4.2 in parallel to in vitro experiments to illustrate the corresponded binding affinities as well as binding site, and involved residues in interaction. These computational results complimented the experimental inhibition activity and enabled us to report a potent urease inhibitors based on β-aryl-β-mercapto ketone scaffold. 相似文献
995.
Screen-printing is one of the most promising approaches towards simple, rapid and inexpensive production of biosensors. Disposable biosensors based on screen printed electrodes (SPEs) including microelectrodes and modified electrodes have led to new possibilities in the detection and quantitation of biomolecules, pesticides, antigens, DNA, microorganisms and enzymes. SPE-based sensors are in tune with the growing need for performing rapid and accurate in-situ analyses and for the development of portable devices. This review (with 226 refs.) first gives an introduction into the topic and then is subdivided into sections (a) on DNA sensors (including methods for the detection of hybridization and damage), (b) on aptasensors (for thrombin, OTA, immunoglobulins and cancer biomarkers), (c) on immunosensors (for microorganisms, immunoglobulins, toxins, hormones, lactoferrin and biomarkers), (d) on enzymatic biosensors (for glucose, hydrogen peroxide, various pharmaceuticals, neurotransmitters, amino acids, NADH, enzyme based sensors). Figure
This review first gives an introduction into the topic of screen-printed electrodes for biosensing and is subdivided into sections (a) on DNA sensors, (b) on aptasensors, (c) on immunosensors, (d) on enzymatic biosensors. It contains 226 references 相似文献
996.
Ali Akbarzadeh Seyed Omid Ranaei Siadat Mostafa Motallebi Mohammad Reza Zamani Mohammad Barshan Tashnizi Sakineh Moshtaghi 《Applied biochemistry and biotechnology》2014,172(4):2253-2265
Bioconversion of cellulosic material into glucose needs cellulase enzymes. One of the most important organisms that produces cellulases is Trichoderma reesei, whose cellulose enzymes are probably the most widely used in the industry. However, these enzymes are not stable enough at high pH and temperatures. The optimized synthetic endoglucanase II gene with Pichia pastoris codon preferences was secretary expressed in P. pastoris. Recombinant enzyme characterization showed maximum activity at pH 4.8 and temperature 75 °C, and it demonstrated increasing thermal stability in high temperature. The enzyme maintained its activity in a wide pH range from 3.5 to 6.5. The optimization of fermentation medium was carried out in shaking flasks. Recombinant protein expression at optimum conditions (pH 7, temperature 25 °C, and 1 % methanol induction) for 72 h demonstrated 2,358.8 U/ml endoglucanase activity units. To our knowledge, this is the highest acidic thermophilic endoglucanase activity that is reported in crude intracellular medium in P. pastoris. We conclude that P. pastoris is an appropriate host for high-level expression of optimized endoglucanase gene with improved thermal stability. 相似文献
997.
Y. C. Goswami Vijay Kumar P. Rajaram V. Ganesan Mohammad Azad Malik Paul O’Brien 《Journal of Sol-Gel Science and Technology》2014,69(3):617-624
Fluorine doped SnO2 nanostructures were grown using ultrasonic assisted sol–gel method. The gel was obtained by dissolving stannous chloride in methanol with ammonium fluoride as dopant followed by irradiation with ultrasonic vibrations. Obtained samples were characterized by structural, morphological and optical studies. All the peaks in the X-ray diffractograms are identified and indexed as tetragonal cassiterite structure. Negative slope of Williamson–Hall plots indicates compressive strain. Particle size of SnO2 nanostructures is decreases with increases in concentration of fluorine doping. Atomic force microscopy, scanning electron microscopy and transmission electron microscopy studies confirm the formation of ring like porous structures and then hollow tube like growth with increase in the fluorine concentration. Peaks in Raman spectra also indicate strong confinement in SnO2 particles. Distinct peaks in the PL spectra make the structure suitable for photovoltaic applications. 相似文献
998.
Mohammad Saraji Malihe Khalili Boroujeni 《Analytical and bioanalytical chemistry》2014,406(8):2027-2066
During the past 7 years and since the introduction of dispersive liquid–liquid microextraction (DLLME), the method has gained widespread acceptance as a simple, fast, and miniaturized sample preparation technique. Owing to its simplicity of operation, rapidity, low cost, high recovery, and low consumption of organic solvents and reagents, it has been applied for determination of a vast variety of organic and inorganic compounds in different matrices. This review summarizes the DLLME principles, historical developments, and various modes of the technique, recent trends, and selected applications. The main focus is on recent technological advances and important applications of DLLME. In this review, six important aspects in the development of DLLME are discussed: (1) the type of extraction solvent, (2) the type of disperser solvent, (3) combination of DLLME with other extraction methods, (4) automation of DLLME, (5) derivatization reactions in DLLME, and (6) the application of DLLME for metal analysis. Literature published from 2010 to April 2013 is covered. 相似文献
999.
A simple, efficient, and ecofriendly procedure has been developed using propane-l,2,3-triyl tris(hydrogen sulfate) as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The significant features of the present protocol are simplicity, environmentally benign, high yields, no chromatographic separation, and recyclability of the catalyst. 相似文献
1000.
Masoud Riazi Ali Reza Keshtkar Mohammad Ali Moosavian 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(2):493-503
Biosorption of thorium(IV) from aqueous solution by Cystoseira indica alga was investigated in batch and fixed-bed column experiments. In the batch study the effects of pH and initial concentration were investigated. The optimum pH for Th(IV) biosorption was found to be 3.5. The experimental isotherms obtained at different pH conditions were analyzed using three two-parameter models and three three-parameter models. Among the two-parameter models the Langmuir model and among the three-parameter models the Redlich–Peterson model vividly described the equilibrium data. The results showed that C. indica alga is a homogeneous biosorbent and Th(IV) biosorption is a favorable and physical process. The maximum biosorption capacity from the Langmuir model was 151.3, 195.7 and 120.6 mg/g at pH 2.5, 3.5 and 4.5, respectively. The continuous isotherm obtained from the column data was modeled by the Langmuir model and the maximum biosorption capacity was 283.8 mg/g. The experimental data were fitted by the use of an analytical and a numerical model, namely Clark and mass transfer models. The results showed that the mass transfer model adequately described the experimental data. Sensitivity analysis revealed that the value of k in has more effect than the axial dispersion coefficient (D z) on the shape of breakthrough curve. 相似文献