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991.
Ahmed Mishaal Mohammed 《中国化学快报》2016,27(5):801-806
This research involves the preparation of a biosensor using silicon oxide for biomedical applications, and its effective use for the detection of target DNA hybridization. An electrochemical DNA biosensor was successfully fabricated by using(3-aminopropyl) tri-ethoxysilane(APTES) as a linker molecule combined with gold nanoparticles(GNPs) on a thermally oxidized SiO_2 thin film. The size of the GNPs was calculated by utilizing UV–vis data with an average calculated particle size within the range of 30±5 nm, and characterization by transmission electron microscopy(TEM) and atomic force microscopy(AFM). The GNP-modified SiO_2 thin films were electrically characterized through the measurement of capacitance, permittivity and conductivity using a low-cost dielectric analyzer. The capacitance, permittivity and conductivity profiles of the fabricated sensor clearly differentiated DNA immobilization and hybridization. 相似文献
992.
Inside Cover: A One‐Pot Chemically Cleavable Bis‐Linker Tether Strategy for the Synthesis of Heterodimeric Peptides (Angew. Chem. Int. Ed. 47/2016)
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993.
We are concerned with an inverse problem for a first-order linear evolution equation. Moreover, a complete second-order evolution equation will be considered, too. We indicate sufficient conditions for existence and uniqueness of a solution. All the results apply well to inverse problems for equations from mathematical physics. As a possible application of the abstract theorems, some examples of partial differential equations are given. 相似文献
994.
995.
N. K. Mohammed J. Mizera N. M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(1):125-128
Nutritional status and toxic elements body burden were evaluated in hair of children living in Zanzibar. 18 samples were collected
from Zanzibar town and 19 samples from Nungwi village, which is approximately 64 km from Zanzibar town. The analysis was carried
out using instrumental neutron activation analysis (INAA). The concentration ranges obtained in this study overlap with the
published elemental values of healthy children of the same age group. The concentration levels of K, Zn, Cu, As and Co in
hair of children from Zanzibar town were higher than from Nungwi whereas levels of Mn, Br and Sr were lower. 相似文献
996.
Zahed Karimi-Jaberi Mohammed M. Hashemi 《Monatshefte für Chemie / Chemical Monthly》2008,14(1):605-608
A simple and environmentally benign procedure for the synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes is described through a one-pot condensation of 2-naphthol with aryl or alkyl aldehydes in the presence of sodium
hydrogen sulfate as a catalyst under solvent-free conditions. 相似文献
997.
Manmeet Singh Manhas Parveen Kumar Faqeer Mohammed Zaheer Khan 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,320(1-3):240-246
Degradation of polyoxyethylene chain of non-ionic surfactant (TritonX-100) by chromium(VI) has been studied spectrophotometrically under different experimental conditions. The reaction rate bears a first-order dependence on the [Cr(VI)] under pseudo-first-order conditions, [TritonX-100] [Cr(VI)] in presence of 1.16 mol dm−3 perchloric acid. The observed rate constant (kobs) was 3.3 × 10−4 to 3.5 × 10−4 s−1 and the half-life (t1/2) was 33–35 min for chromium(VI). The effects of total [TritonX-100] and [H+] on the reaction rate were determined. Reducing nature of non-ionic TritonX-100 surfactant is found to be due to the presence of –OH group in the polyoxyethylene chain. It was observed that monomeric and non-ionic micelles of TritonX-100 were oxidized by chromium(VI). When [TritonX-100] was less than its critical micelle concentration (cmc) the kobs values increased from 0.76 × 10−4 to 1.5 × 10−4 s−1. As the [TritonX-100] was greater than the cmc, the kobs values increases from 2.1 × 10−4 to 8.2 × 10−4 s−1 in presence of constant [HClO4] (1.16 mol dm−3) at 40 °C. A comparison was made of the oxidative degradation rates of TritonX-100 with different metal ion oxidants. The order of the effectiveness of different oxidants was as follows: permanganate > diperiodatoargentate(III) > chromium(VI) > cerium(IV). 相似文献
998.
Aly SM Ho CL Fortin D Wong WY Abd-El-Aziz AS Harvey PD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(27):8341-8352
The synthesis of polymers of the type (-Cz-C[triple chemical bond]C-PtL(2)-C[triple chemical bond]C-Cz-X-)(n) along with the corresponding model compounds (Ph-PtL'(2)-C[triple chemical bond]C-Cz)(2)-X-, where Cz=3,3'-carbazole, X=nothing, Cz, or F (2,2'-fluorene), L=PBu(3), and L'=PEt(3) are reported. The electronic spectra (absorption, excitation, emission, and ns-transient spectra) and the photophysics of these species in 2-methyltetrahyrofuran (2MeTHF) at 298 and 77 K are presented. Evidence for singlet electron and triplet energy transfer from the Cz chromophore to the F moiety are provided and discussed in detail. The rate for electron transfer is very fast (>4 x 10(11) s(-1)), whereas that for triplet-triplet energy transfer is much slower (approximately 10(3) s(-1)). This work represents a very rare example of studies that address electronic communication in the backbone of a conjugated organometallic polymer. 相似文献
999.
ZGOU Hsaine HAMIDI Mohamed LERE-PORTE Jean-Pierre SEREIN-SPIRAU Francoise BOUACHRINE Mohammed 《物理化学学报》2008,24(1):37-40
Theoretical study on the geometries and electronic properties of new conjugated compounds based on thiophene and phenylene was carried out. The theoretical ground-state geometries and electronic structures of the studied molecules were obtained using the density functional theory (DFT) method at B3LYP level with 6-31G(d) basis set. The electronic properties were determined by ZINDO/s, CIS/3-21G(d), and TD//B3LYP/3-21G(d) calculations performed on the B3LYP/6-31(d) optimized geometries. The effects of the ring structure and the substituents on the geometries and electronic properties of these materials were discussed. The results of this study indicate how the electronic properties can be tuned by the backbone ring or side group and suggest these compounds as good candidates for opro-electronic applications. 相似文献
1000.
A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of benzoyl peroxide and the related compounds benzoic acid (BA), methylparaben, benzaldehyde, propylparaben, and ethyl benzoate. The compounds are separated on a column containing octadecyl silane chemically bonded to porous silica particles. The mobile phase is acetonitrile-buffer (45 + 55, v/v). Solutions are injected into the chromatographic system under isocratic conditions at a constant flow rate of 1.5 mL/min with UV detection at 235 nm. Analysis of stability samples showed rapid accumulation of BA by thermal degradation. A rationale has been established for the acceptable limit of BA in the formulation, which already contains BA (0.2%) as a preservative. The proposed method is efficient and determines the active compound and 5 related compounds in a run time of 20 min. The method was validated according to the guidelines of the International Conference on Harmonization and demonstrated good agreement with the validation requirements. 相似文献