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991.
We herein report a serendipitously observed acid mediated rearrangement of monoethylene ketal of 2-methyl-2-(3-methylbut-2-en-1-yl)cyclohex-4-ene-1,3-diones to Dihydrobenzopyran and demonstrated the application of this methodology in the construction of core carbon scaffolds of dimethoxyajacareubin, cariphenone-A and crotamadine. 相似文献
992.
Xue Li Kang Zhao Caiyin You Wensheng Linghu Feng Ye Mei Yu Ahmed Alsaedi Tasawar Hayat Hui Pan Jie Luo Xuemei Ren 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(3):509-522
The characterization of the nanocomposites (PANI@GO) by SEM, TEM, Raman and FT-IR indicated that the GO has been functionalized via PANI successfully. PANI@GO as a novel platform for the removal of Cd(II), Eu(III), Th(IV) and U(VI) from aqueous solutions, the uptake process was a spontaneous endothermic process, and is strongly dependent of pH but independent of ionic strength. The adsorption kinetic and isotherm were fitted well the Pseudo-second-order equation and Langmuir model. PANI@GO were recycled and re-used without significant loss of adsorption capacity, and real samples were also treated which showed that had little interference with the performance of it. 相似文献
993.
Ahmed I. Hashem Marwa El-Hussieny Mansoura A. Abd-El-Maksoud Soher S. Maigali Shaimaa T. Mansour 《Phosphorus, sulfur, and silicon and the related elements》2018,193(1):1-9
Reactions of nucleophilic active phosphacumulenes with iso(thio)cyanate compounds were performed. The reaction products depend on the nature of the reagent, substrate and the condition of the reaction used. New heterocyclic 4-membered or 6-membered sulfur and nitrogen compounds such as phosphoranylidene thietane, azetidine and thiazinane were obtained. On the other hand, the stable phosphonium ylides with the iso(thio)cyanate afforded phosphoranylidene thiocarbamoyl derivatives. Possible reaction mechanisms are considered and the structural assignments are based on compatible analytical and spectroscopic data. 相似文献
994.
Yhiya Amen Qinchang Zhu Hai-Bang Tran Mohamed S. Afifi Ahmed F. Halim Ahmed Ashour 《Natural product research》2018,32(16):1955-1959
Rho-kinase enzymes are one of the most important targets recently identified in our bodies. Several lines of evidence indicate that these enzymes are involved in many diseases and cellular disorders. ROCK inhibitors may have clinical applications for cancer, hypertension, glaucoma, etc. Our study aims to identify the possible involvement of Rho-kinase inhibition to the multiple biological activities of adlay seeds and provide a rationale for their folkloric medicines. Hence, we evaluated Rho-kinase I and II inhibitory activity of the ethanol extract and 28 compounds derived from the seeds. A molecular docking assay was designed to estimate the binding affinity of the tested compounds with the target enzymes. The results of our study suggest a possible involvement of Rho-kinase inhibition to the multiple biological activities of the seeds. Furthermore, the results obtained with the tested compounds revealed some interesting skeletons as a scaffold for design and development of natural Rho-kinase inhibitors. 相似文献
995.
Bouchra Belhaj Abdallah Ahmed Landoulsi Abdelwaheb Chatti 《Journal of Saudi Chemical Society》2018,22(1):110-118
The instant biosynthesis of silver nanoparticles under static electromagnetic induction, its antibacterial activity and its post exposure monitoring were reported here. A mix of silver nitrate solution and Ruta chalepensis leaf extract was irradiated by a static electromagnetic field (SMF) of 200 mT. The characteristics and stability of the biosynthesized silver nanoparticles (Ag NPs) were determined. Compared to the non-irradiated exposure, the morphology and state of the obtained material change once the exposition to SMF is turned off. Shifting from 453 to 473 nm, the percentage of the needles shaped silver nanoparticles increased and continue to win and dominate the biomixture toward the spherical silver nanoparticles. TEM microscopy showed a wide range of silver materials designed in different nanoscale morphology and beyond where they undergo major changes affecting mainly the size, shape and form (dispersity) of nanosilver. 相似文献
996.
Banazadeh Alireza Williamson Seth Zabet Masoud Hussien Ahmed Mechref Yehia 《Analytical and bioanalytical chemistry》2018,410(28):7395-7404
Analytical and Bioanalytical Chemistry - More than 50% of all known proteins are glycosylated, which is critical for many biological processes such as protein folding and signal transduction.... 相似文献
997.
Kramer’s sampling theorem provides an algorithm for reconstructing a function ?, in the form $$ f(t)=\int_{a}^{b}\ F(x)K(x,t)dx,\qquad {\rm for\ some}\ F\ \in\ L^{2}(a,b), $$ from its values at a discrete set of points. In all the known examples, the kernel of the transform, K(x,t) is continuous in x and entire in t, even though the proof of the theorem shows that the continuity in x is not essential. This raises the question of whether it is possible to find an example of Kramer’s theorem with a discontinuous kernel. The aim of the paper is to answer this question in the affirmative. We show how one can construct a family of discontinuous kernels for which Kramer’s theorem holds and, in addition, each member of this family arises from a Sturm-Liouville problem, but with discontinuous initial conditions. 相似文献
998.
Saira Shahzadi Saqib Ali Amin Badshah Farkhanda Shaheen Fiaz Ahmed Mohammed Fettouhi 《Journal of chemical crystallography》2006,36(9):567-570
The complex bis(4-methylpiperidine-dithiocarbamato-S,S′)-palladium(II) was synthesized by the reaction of 4-methyl-1-piperidine dithiocarbamic acid with palladium(II) chloride. Its structure was determined by X-ray crystal diffraction analysis. It crystallizes in the monoclinic P21/c space group with the crystal cell parameters a=8.6491(8) ?, b=18.7305(16) ?, c=11.9933(10) ?, β=107.074(1)°, V=1857.3(3) ?3 and Z=4. The palladium (II) ion is bonded to four sulfur atoms, belonging to two dithiocarbamate ligands, in a distorted square planar geometry. The X-ray data suggest a pronounced electronic delocalization in the two NCS2 moieties. 相似文献
999.
Optical antipodes of the mono- and disubstituted polyhalo norbornyl derivatives were prepared in excellent yields. The monosubstituted derivatives 7 were obtained with good enantiopurities. A kaleidoscopic change in the product formation and distribution was observed by changing the chronology of reactions. 相似文献
1000.
Given a strictly convex, smooth, and bounded domain Ω in we establish the existence of a negative convex solution in with zero boundary value to the singular Monge–Ampère equation det(D2u)=p(x)g(−u). An associated Dirichlet problem will be employed to provide a necessary and sufficient condition for the solvability of the singular boundary value problem. Estimates of solutions will also be given and regularity of solutions will be deduced from the estimates. 相似文献