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291.
W. Rehman M. K. Baloch A. Badshah S. Ali 《Russian Journal of Coordination Chemistry》2005,31(12):856-860
The synthesis and study of new coordination compounds of some organotin(IV) chlorides with monomethyl glutarate are reported. The ligand molecule appears to be bound to the tin atom through the carboxylic oxygen. The results obtained from 1H, 13C, and 119Sn NMR, FT-IR and 119Sn Mossbauer spectra show that the complexes are pentacoordinated with the trigonal bipyramidal structure. Biological screening of organotin(IV) derivatives shows promising activity, especially for the triphenyltin complex exhibiting higher antifungal activity. In addition, the rest of the compounds also prove to be active against various fungi used. 相似文献
292.
We explain Fermi acceleration of particles bouncing in a gravitational field and experiencing a force due to a modulated evanescent laser field. The acceleration strongly depends upon the initial conditions in the phase space and certain modulation amplitude. We study the accelerated modes by the Poincaré surface of sections and Lyapunov exponents. Furthermore, we identify the initial areas of the phase space that support accelerated dynamics and write a mapping for accelerated dynamics. We show that a distinction between accelerated and chaotic evolutions can be made with the help of the aspect ratio. The Lyapunov exponent shows that the accelerated mode supports ordered evolution. 相似文献
293.
Wajid Rehman Musa Kaleem Baloch Amin Badshah 《Russian Journal of Inorganic Chemistry》2007,52(1):102-107
The results of an investigation into the fungicidal properties of some organotin(IV) compounds with Mono-methyl phthalate are reported. The compounds were characterized by various spectroscopic techniques including 1H-13C-119Sn-NMR, FT-IR, and 119Sn Mössbauer studies. On the basis of these techniques, all the complexes show penta coordination with a trigonal bipyramidal environment around the tin. The synthesized compounds were tested against a number of plant pathogenic fungi. The fungicidal data reveal that the tri-phenyltin(IV) compound proves to be a powerful fungicide. Comparison between the fungicidal activity of the trialkyltin(IV) compounds shows that the tri-phenyl tin(IV) complex is most active against all plant pathogens; the rest of the complexes also exhibit significant antifungal activity but less than the former one. 相似文献
294.
In this paper, the steady incompressible Navier–Stokes equations are discretized by the finite element method. The resulting systems of equations are solved by preconditioned Krylov subspace methods. Some new preconditioning strategies, both algebraic and problem dependent are discussed. We emphasize on the approximation of the Schur complement as used in semi implicit method for pressure‐linked equations‐type preconditioners. In the usual formulation, the Schur complement matrix and updates use scaling with the diagonal of the convection–diffusion matrix. We propose a variant of the SIMPLER preconditioner. Instead of using the diagonal of the convection–diffusion matrix, we scale the Schur complement and updates with the diagonal of the velocity mass matrix. This variant is called modified SIMPLER (MSIMPLER). With the new approximation, we observe a drastic improvement in convergence for large problems. MSIMPLER shows better convergence than the well‐known least‐squares commutator preconditioner which is also based on the diagonal of the velocity mass matrix. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
295.
Mohammed Mansour Quradha Rasool Khan Mujeeb-ur- Rehman Abdulrahman Abohajeb 《Natural product research》2019,33(17):2554-2559
Chemical composition, antioxidant, anticancer, and antimacrobial activities of essential oil obtained from leaves of Rumex nervosus has been evaluated here for the first time. GC/MS analysis reveals the presence of Palmitoleic Acid (28.35%) and Palmitic acid, (25. 37%) as their methyl ester as major components. The essential oil showed significant DPPH radical scavenging activity (94.907 ± 0.1089% and 94.003 ± 0.0749%) at concentration (100 and 80) μg/mL respectively. The oil showed promising activity against staph aureus, while showed weak activity against (Hela and 3T3) cell lines. The crude extract / fractions of R. nervosus (leaves) showed significant antioxidant activity at dose (100 and 80) μg/mL. Futhermore the crude showed significant activity against (MCF-7 and MDA-MB-231) cell lines with IC50 (20.5138 ± 0.933 and 25.1728 ± 0.9176) μg/mL respectively, and chloroform fraction showed good activity against (MCF-7 and MDA-MB-231) cell lines with IC50 (31.154 ± 0.965 and 42.269 ± 2.1045) μg/mL. 相似文献
296.
Shah Saud Guoqing Li Yingjie Sun Muhammad Idrees Khan Ashfaq Ur Rehman Asad Uzzaman Weiwen Liu Chan Ding Hua Xiao Yuxing Wang Chengxi Cao 《Electrophoresis》2019,40(20):2767-2774
A novel analytical protocol was developed for general quality screening of chicken meat based on IEF and protein extraction. To demonstrate the developed protocol, 24 chickens were divided into three groups; each had eight chickens. The chickens in Group 1 were slaughtered by exsanguination, Group 2 asphyxiated in water, and that in Group 3 were infected by new castle disease virus. Proteins were extracted from the meat samples by using pure water as an extractant, separated by IEF, verified by western blot, and quantified via imaging analysis. The relevant experiments demonstrated that two myoglobin (Mb) bands were detected at pI 6.8 and 7.04 for all samples of Groups 1, 2, and 3, but there were additional hemoglobin (Hb) bands at pI 7.09 and 7.13 (P < 0.05) for the samples of Groups 2 and 3. The results implied that Hb bands might be a potential biomarker for the screening of chicken meat quality. The RSD values of two Mb bands (pI 6.8 and 7.04) in Group 1 were respectively 4.08 and 3.63%, the ones of two Hb bands (pI 7.09 and 7.13) in Group 2 were 3.66 and 2.10%, and those in Group 3 were 2.17% and 2.77%, respectively. All the RSD values indicated high stability and reliability of the developed protocol. Additionally, the protocol had a direct readout of protein bands in IEF without staining. However, it was time‐consuming and had high cost. Even so, the relevant general method and finding have potential for screening of chicken meat quality. 相似文献
297.
Kinetic theory has been applied to study the damping characteristics of dust ion acoustic waves (DIAWs) in a dusty plasma comprising q‐non‐extensive distributed electrons and ions, while the dust particles are considered extensive following the Maxwellian velocity distribution function. It is found that the results of the three‐dimensional velocity distribution function are more accurate compared to the results of the one‐dimensional velocity distribution function. The numerical solution of the dispersion relation is carried out to study the effect of the non‐extensivity parameter q on the dispersion, the damping rate, and the range of the values of the normalized wavenumber ( k λD) for which the DIAWs are weakly damped. It is found that the change in the value of the electron non‐extensivity parameter qe has a minor effect on the dispersion, the damping rate, and the range of the values of the normalized wavenumber ( k λD) for which the DIAWs are weakly damped, while on the other hand, ion non‐extensivity parameter qi has a strong effect on these arguments. The effect of other parameters, such as the ratio of electron to ion number density and ratio of electron to ion temperature, on the damping characteristics of DIAWs is also highlighted. 相似文献
298.
Sadiq‐ur‐Rehman Saqib Ali M. Mazhar Amin Badshah Masood Parvez 《Heteroatom Chemistry》2006,17(5):420-432
The complexes Me2SnL2 ( I ), Me3SnL ( II ), Et2SnL2 ( III ), n‐Bu2SnL2 ( IV ), n‐Bu3SnL ( V ), n‐Oct2SnL2 ( VI ), Bz2SnL2 ( VII ), and Ph3SnL ( VIII ), where “L” is ( E )‐3‐(3‐fluorophenyl)‐2‐phenyl‐2‐propenoate, have been prepared and structurally characterized by means of elemental analysis, infrared, mass, and multinuclear (1H, 13C, 119Sn) NMR spectral techniques. The spectroscopic results showed that the geometry around the Sn atom in triorganotin(IV) derivatives is four‐coordinated in noncoordinating solvent and behaves as five‐coordinated linear polymers with bridging carboxylate groups or five‐coordinated monomers, both acquiring trans‐R3SnO2 geometry for Sn in the solid state. While all the diorganotin(IV) derivatives may acquire trigonal bipyramidal structures in solution due to collapse of the Sn←OCO interaction and octahedral geometries in the solid state, which have been confirmed by the X‐ray crystallographic data of the compound III . The crystal structure of Et2SnL2 ( III ) has been determined by X‐ray crystallography and is found skew‐trapezoidal bipyramidal, which substantiates that the ligand acts as an anisobidentate chelating agent, thus rendering the Sn atom six coordinated. The crystal is monoclinic with space group C21/n. All the investigated compounds have also been screened for biocidal and cytotoxicity data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:420–432, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20243 相似文献
299.
Nidhil M. A. Rehman Anuj Kumar Ratnesh K. Shukla 《Theoretical and Computational Fluid Dynamics》2017,31(3):251-280
The presence of a finite tangential velocity on a hydrodynamically slipping surface is known to reduce vorticity production in bluff body flows substantially while at the same time enhancing its convection downstream and into the wake. Here, we investigate the effect of hydrodynamic slippage on the convective heat transfer (scalar transport) from a heated isothermal circular cylinder placed in a uniform cross-flow of an incompressible fluid through analytical and simulation techniques. At low Reynolds (\({\textit{Re}}\ll 1\)) and high Péclet (\({\textit{Pe}}\gg 1\)) numbers, our theoretical analysis based on Oseen and thermal boundary layer equations allows for an explicit determination of the dependence of the thermal transport on the non-dimensional slip length \(l_s\). In this case, the surface-averaged Nusselt number, Nu transitions gradually between the asymptotic limits of \(Nu \sim {\textit{Pe}}^{1/3}\) and \(Nu \sim {\textit{Pe}}^{1/2}\) for no-slip (\(l_s \rightarrow 0\)) and shear-free (\(l_s \rightarrow \infty \)) boundaries, respectively. Boundary layer analysis also shows that the scaling \(Nu \sim {\textit{Pe}}^{1/2}\) holds for a shear-free cylinder surface in the asymptotic limit of \({\textit{Re}}\gg 1\) so that the corresponding heat transfer rate becomes independent of the fluid viscosity. At finite \({\textit{Re}}\), results from our two-dimensional simulations confirm the scaling \(Nu \sim {\textit{Pe}}^{1/2}\) for a shear-free boundary over the range \(0.1 \le {\textit{Re}}\le 10^3\) and \(0.1\le {\textit{Pr}}\le 10\). A gradual transition from the lower asymptotic limit corresponding to a no-slip surface, to the upper limit for a shear-free boundary, with \(l_s\), is observed in both the maximum slip velocity and the Nu. The local time-averaged Nusselt number \(Nu_{\theta }\) for a shear-free surface exceeds the one for a no-slip surface all along the cylinder boundary except over the downstream portion where unsteady separation and flow reversal lead to an appreciable rise in the local heat transfer rates, especially at high \({\textit{Re}}\) and Pr. At a Reynolds number of \(10^3\), the formation of secondary recirculating eddy pairs results in appearance of additional local maxima in \(Nu_{\theta }\) at locations that are in close proximity to the mean secondary stagnation points. As a consequence, Nu exhibits a non-monotonic variation with \(l_s\) increasing initially from its lowermost value for a no-slip surface and then decreasing before rising gradually toward the upper asymptotic limit for a shear-free cylinder. A non-monotonic dependence of the spanwise-averaged Nu on \(l_s\) is observed in three dimensions as well with the three-dimensional wake instabilities that appear at sufficiently low \(l_s\), strongly influencing the convective thermal transport from the cylinder. The analogy between heat transfer and single-component mass transfer implies that our results can directly be applied to determine the dependency of convective mass transfer of a single solute on hydrodynamic slip length in similar configurations through straightforward replacement of Nu and \({\textit{Pr}}\) with Sherwood and Schmidt numbers, respectively. 相似文献
300.