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51.
52.
On‐plate enzyme and inhibition assay of glucose‐6‐phosphate dehydrogenase using thin‐layer chromatography
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Miaomiao Tian Amara Camara Mohamed Shengtian Wang Li Yang 《Journal of separation science》2015,38(16):2907-2914
We performed on‐plate enzyme and inhibition assays of glucose 6‐phosphate dehydrogenase using thin‐layer chromatography. The assays were accomplished based on different retardation factors of the substrates, enzyme, and products. All the necessary steps were integrated on‐plate in one developing process, including substrate/enzyme mixing, reaction starting, and quenching as well as product separation. In order to quantitatively measure the enzyme reaction, the developed plate was then densitometrically evaluated to determine the peak area of the product. Rapid and high‐throughput assays were achieved by loading different substrate spots and/or enzyme (and inhibition) spots in different tracks on the plate. The on‐plate enzyme assay could be finished in a developing time of only 4 min, with good track‐to‐track and plate‐to‐plate repeatability. Moreover, we determined the Km values of the enzyme reaction and Ki values of the inhibition (Pb2+ Cd2+ and Cu2+ as inhibitors), as well as the corresponding kinetics using the on‐plate assay. Taken together, our method expanded the application of thin‐layer chromatography in enzyme assays, and it could be potentially used in research fields for rapid and quantitative measurement of enzyme activity and inhibition. 相似文献
53.
Mourad Hidouri Alain Wattiaux Léopold Fournés Jacques Darriet Mongi B. Amara 《Comptes Rendus Chimie》2011,14(10):904-910
Na2Mn2(1 − x)Cd2xFe(PO4)3 (0 ≤ x ≤ 1) phosphates were prepared by solid state reaction and characterized by powder X-ray diffraction, magnetic susceptibility and Mössbauer spectroscopy. The X-ray diffraction patterns indicated the formation of a continuous solid solution which crystallizes in the alluaudite structural type characterized by the general formula X(2)X(1)M(1)M(2)2(PO4)3. The cation distribution, deduced from a structure refinement of the x = 0, 0.5 and 1 compositions, is ordered in the X(2) sites and disordered in the remaining X(1), M(1) and M(2) sites. The magnetic susceptibility study revealed an antiferromagnetic behaviour of the studied compounds. The 57Fe Mössbauer spectroscopy confirmed the structural results and proved the exclusive presence of Fe3+ ions. 相似文献
54.
M. A. Boukli Hacene S. Amara N. E. Chabane Sari 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1363-1369
Ground source heat pumps (GSHPs) mean attractive heating and cooling systems. Optimum design of a borehole heat exchanger
(BHE), as the outer part of a GSHP heating system, requires knowledge of the thermal properties of the soil. Those data, the
effective thermal conductivity of the soil λeff and the average temperature of the soil T
0 enable us to determine the necessary number and depth of boreholes. The determination of thermal conductivity of the soil
in laboratory experiments does not usually coincidence with the data under in situ conditions. Therefore, an in situ method
of experimental determination of these parameters, thermal response testing (TRT) is used primarily for in situ determination
of design data for BHEs. In this study, which was the first TRT in Algeria (Tlemcen site), the purpose was to determine the
effective ground thermal conductivity. Measured data were evaluated by the line source model. Used method and performed evaluation
are presented for a borehole drilled in clay, silt, and sand. The resulting effective ground thermal conductivity was 1.364 W/m K
and the borehole thermal resistance was 0.18 K/(W/m). 相似文献
55.
Z Amara E Drège C Troufflard P Retailleau D Joseph 《Organic & biomolecular chemistry》2012,10(35):7148-7157
Novel 2,5-meso-pyrrolidines have been straightforwardly synthesized from readily available symmetrical double Michael acceptors. The key step rested on an aza-Michael addition of primary alkylamines to bis-enones. Competitive Rauhut-Currier and aza-Michael reactions have been highlighted in protic solvent. Ultrasound activation associated with solvent-free conditions led to the expected pyrrolidines in quantitative yields and excellent stereoselectivities. The optimized conditions have been extended to the sonochemical synthesis of pyrrolidine Lobelia alkaloids analogues in short sequences. 相似文献
56.
Anh Ngoc Ngo Khadija El Kassimi Zacharias Amara Emmanuelle Drège Delphine Joseph 《Tetrahedron letters》2012,53(26):3296-3300
To reach densely functionalized 1-azabicyclo[3.3.1]nonane frameworks synthesis, a stereocontrolled bridging Michael addition involving an unexplored C-5/C-6 disconnection strategy was studied. 1-Azabicyclo[3.3.1]nonane scaffolds have been diastereoselectively elaborated in fairly good yields by two concise pathways implying pyrrolidine derivative organocatalyst or enantiopure 1-phenylethylamine. 相似文献
57.
Hayet Benzarouk Abdelaziz Drici Mounira Mekhnache Abdelaziz Amara Mouhamed Guerioune Jean Christian Bernède Hacen Bendjffal 《Superlattices and Microstructures》2012
In the present work we studied the influence of the dopant elements and concentration on the microstructural and electrochemical properties of ZnO thin films deposited by spray pyrolysis. Transparent conductive thin films of zinc oxide (ZnO) were prepared by the spray pyrolysis process using an aqueous solution of zinc acetate dehydrate [Zn(CH3COO)2·2H2O] on soda glass substrate heated at 400 ± 5 °C. AlCl3, MgCl2 and NiCl2 were used as dopant. The effect of doping percentage (2–4%) has been investigated. Afterwards the samples were thermally annealed in an ambient air during one hour at 500 °C. X-ray diffraction showed that films have a wurtzite structure with a preferential orientation along the (0 0 2) direction for doped ZnO. The lattice parameters a and c are estimated to be 3.24 and 5.20 ?, respectively. Transmission allowed to estimate the band gaps of ZnO layers. The electrochemical studies revealed that the corrosion resistance of the films depended on the concentration of dopants. 相似文献
58.
The Sturm-Liouville problem is considered with a singular potential q(x) representing the derivative of a real function from the space L 2[0, 1] in the distributional sense. Two approaches are developed for the study of oscillation properties of eigenfunctions of this problem. The first approach is based on generalization of methods of the Sturm theory. The second one is based on development of variational principles.
相似文献
$\begin{array}{*{20}c} { - y'' + q(x)y = \lambda y,} \\ {y(0) = y(1) = 0} \\ \end{array} $
59.
Geoffrey Schwertz Andrea Zanetti Marllon Nascimento de Oliveira Mario Andrès Gomez Fernandez Fabienne Dioury Janine Cossy Zacharias Amara 《Tetrahedron》2019,75(6):743-748
Amorphadiene is a natural product involved in the biosynthesis of the antimalarial drug artemisinin. A convenient four-step synthesis of amorphadiene, starting from commercially available dihydroartemisinic acid, is reported. The targeted molecule is isolated with an overall yield of 85% on a multi-gram scale in four steps with only one chromatography. 相似文献
60.
Dr. M. John Plater Amara Darr Catriona Crawford Craig Murray Struan Simpson Prof. William T. A. Harrison Prof. Juan M. Clemente-Juan 《ChemistryOpen》2019,8(9):1204-1208
The synthesis of a Cu4(OH)4 cube which is coordinated by four molecules of the dipyridyl ligand 1,6-[di(pyridin-4-yl)hex-3-ene] is reported. This compound has a trans double bond which restricts the conformational freedom of the ligand and favours coordination within a unique copper cube. The structure was solved by an X-Ray single crystal structure determination and low temperature magnetic susceptibility measurements examined its magnetic properties. The cube classification corresponds to the type I classification of Mergehenn and Haase and the short/long distribution of Cu ⋅⋅⋅ Cu separations in the cube as defined by Ruiz. The magnetic susceptibility measurements show paramagnetic behaviour down to 50 K but below this the copper cube shows weak ferromagnetic exchange interactions. The low temperature magnetic susceptibility characteristics are examined in detail then modelled and compared to other similar Cu4O4 copper cubes. 相似文献