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41.
Riaz A. Usmani 《Journal of Computational and Applied Mathematics》1980,6(2):93-98
Methods of order 2, and 4 are developed for the continuous approximation of the solution of a two-point boundary value problem involving a fourth order linear differential equation via quintic and sextic spline functions. In three typical numerical examples, the results are briefly summarized to demonstrate the practical usefulness of the methods. 相似文献
42.
The reaction of 6-aminoeoumarin with some ethoxymethylene compounds and dimethyl acetylenedicarboxylate led to condensation products which on thermal cyclizations afford new derivatives of 3H-pyrano[3,2-f]quinoline (IIa-IIc). 相似文献
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44.
A. M. Usmani 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8-9):1237-1246
Open pore urea/formaldehyde (OPUF) polymers were developed by Usmani and co-workers. They are composed of agglomerated spherical particles (0.1–10 μm in diameter) bonded to one another in a rigid, highly permeable structures. In this paper we describe the applications of OPUF and the development of potential technologies therefrom. 相似文献
45.
Nurul Ain Mazlan Thahira Begum S. A. Ravoof Edward R. T. Tiekink Mohamed Ibrahim Mohamed Tahir Abhi Veerakumarasivam Karen A. Crouse 《Transition Metal Chemistry》2014,39(6):633-639
Salicylaldehyde-4-methylthiosemicarbazone (H2MTSali) has been prepared via the condensation reaction of 4-methyl-3-thiosemicarbazide and salicylaldehyde. Four new mixed-ligand copper(II) and nickel(II) complexes with a general formula [M(MTSali)L] (M = Cu2+ or Ni2+; L = co-ligand) were synthesized, where L is either imidazole (im) or benzimidazole (bzim). The Schiff base and its mixed-ligand complexes were characterized by IR and UV/Vis spectroscopy, and the complexes by molar conductivity and magnetic susceptibility measurements. The spectroscopic data indicated that the Schiff base behaves as a tridentate ONS donor ligand coordinating via the phenoxide-oxygen, azomethine-nitrogen, and thiolate-sulphur atoms. Magnetic data indicate a square planar environment for the nickel(II) complexes while molar conductance values indicate that the metal complexes are essentially non-electrolytes in DMSO solution. X-ray crystallography shows Cu(MTSali)bzim (1) and Ni(MTSali)bzim (3) to be isostructural, with the metal(II) ions being coordinated by a N2OS donor set that defines an approximate square planar geometry; in both cases, the benzimidazole is splayed with respect to the coordination plane. The copper(II) complexes were active against MDA-MB-231 and MCF-7 breast cancer cell lines, more so than H2MTSali, whereas the nickel(II) complexes were inactive. 相似文献
46.
Sheraz A. K. Tanoli Nazish U. Tanoli Saman Usmani Zaheer-Ul-Haq Antonio G. Ferreira 《Central European Journal of Chemistry》2014,12(3):332-340
Larger size or novel structure molecules are always appreciated by all fields of experimental and computational science. Conversely, molecules with smaller size and simple structures are usually ignored with no explanation as to why. However, the vast majority of more diminutive molecules behave as a cornerstone in the synthesis of a bigger structural framework. Subsequently, we planned to uncover the interactions of small molecules towards macromolecules, and successfully presented the binding results of 2-aminopyridine and Isovanillin towards BSA through NMR techniques. STD epitope mapping and also the DOSY results provided evidence that Isovanillin remained closer to the binding cavity of protein. Titration experiments afforded 584 µM (0.584mM) and 487 µM (0.487 mM) dissociation constants for isovanillin and 2-aminopyridine respectively. Furthermore, changes in diffusion coefficient (with and without protein addition in DOSY spectra) were found to be 0.081 log (m2 s?1) and 0.096 log (m2 s?1) points for isovanillin and 2-aminopyridine respectively. Docking studies exhibit that these molecules can tie to site 1 (sub-area IIA) through the pi-pi interaction and hydrogen bonding with Trp213. Our results demonstrated that both compounds could be utilized as part of a transporter in the circulatory system and their extension-inspired compounds may be utilized in new drug design. 相似文献
47.
The binding energies of the ΛΛ hypernuclei 10ΛΛBe and 6ΛΛHe are calculated variationally with a 2α + 2Λ and with an α + 2Λ model, respectively. For 10ΛΛBe the integrations were made with Monte Carlo techniques while for 6ΛΛHe direct numerical methods were used. A wide range of phenomenological ΛΛ potentials based on meson-exchange models was considered. An approximately universal linear relation between the calculated values of and of is obtained. For the experimental value of this relation predicts a much too small value of , well below the lower limit of the quoted experimental value of 10.9 ± 0.6 MeV. For ΛΛ potentials with repulsive cores the relations, for a given , between the low-energy ΛΛ scattering parameters a, r0 and the intrinsic range b are both approximately universal and independent of the detailed potential shape. For the experimental value of the preferred values are 2.5 ? ?a ? 3.5 fm, 2.6 ? r0 ? 3.1 fm. The large and negative values of a correspond to conditions not too far from a bound 1S0 ΛΛ state and could indicate a 6-quark dibaryon state with the same quantum numbers and above the ΛΛ threshold. 相似文献
48.
Several N-(2,4-dinitrophenyl)nitroazoles which cannot be obtained by direct nitration of N-phenylazoles have been prepared by condensation of 2,4-dinitrofluorobenzene with the appropriate nitroazoles. The structures of the products are assigned on the basis of their proton magnetic resonance spectra; in all the examples studied, condensations occur at positions remote from the nitro group of the nitroazole. 相似文献
49.
50.
Dr. Ain Uddin Seth R. Allen Adrian K. Rylski Connor J. O'Dea Dr. Jack T. Ly Dr. Tod A. Grusenmeyer Dr. Sean T. Roberts Dr. Zachariah A. Page 《Angewandte Chemie (International ed. in English)》2023,62(22):e202219140
The use of visible light to drive polymerizations with spatiotemporal control offers a mild alternative to contemporary UV-light-based production of soft materials. In this spectral region, photoredox catalysis represents the most efficient polymerization method, yet it relies on the use of heavy-atoms, such as precious metals or toxic halogens. Herein, spin-orbit charge transfer intersystem crossing from boron dipyrromethene (BODIPY) dyads bearing twisted aromatic groups is shown to enable efficient visible light polymerizations in the absence of heavy-atoms. A ≈5–15× increase in polymerization rate and improved photostability was achieved for twisted BODIPYs relative to controls. Furthermore, monomer polarity had a distinct effect on polymerization rate, which was attributed to charge transfer stabilization based on ultrafast transient absorption and phosphorescence spectroscopies. Finally, rapid and high-resolution 3D printing with a green LED was demonstrated using the present photosystem. 相似文献