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781.
Cynthia Demicheli Rosemary Ochoa Ivana Silva Lula Fabio C. Gozzo Marcos N. Eberlin Frdric Frzard 《应用有机金属化学》2003,17(4):226-231
Two simple and efficient procedures for the preparation of pentavalent antimony derivatives are described, using either antimony pentachloride (SbCl5) or potassium hexahydroxoantimonate (KSb(OH)6) as sources of antimony(V). These two new methods are evaluated for the synthesis of an important anti‐leishmanial drug: meglumine antimonate. Using elemental (carbon, hydrogen, nitrogen) and thermal analysis, atomic absorption (antimony), proton NMR spectroscopy and high‐resolution positive‐ion electrospray ionization mass spectrometry (ESI(+)‐MS), products for the reaction with N‐methyl‐D ‐glucamine (NMG) using both the SbCl5 and KSb(OH)6 methods were characterized and found to be similar to a commercial sample of the drug. The only notable difference was observed for the ESI‐MS spectrum of the KSb(OH)6 product; it displays the same pattern of ESI‐generated ions as those of both the SbCl5 product and the commercial drug, but with significantly different abundance ratios. NMR data indicate that the NMG molecules coordinate antimony in two different fashions, which suggests either the coexistence of two different complexes or the existence of a single major complex in which two NMG molecules are coordinated with antimony in an asymmetrical geometry. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
782.
783.
Velimir Popsavin Sanja Grabe? Ivana Krsti? Gordana Bogdanovi? 《Tetrahedron letters》2004,45(51):9409-9413
A new approach to the dephenyl goniofufurone analogue 2 and the corresponding (3S,4R)-stereoisomer 3 is reported. The resulting furanolactones 2 and 3 have shown a potent and selective in vitro cytotoxicity against certain human tumour cell lines. 相似文献
784.
Christopher D. Thompson Evan G. Robertson Ivana Aleksic Don McNaughton 《Journal of Molecular Spectroscopy》2005,230(2):81
The FTIR spectrum of pentafluoroethane (R125) was measured in the mid infrared region from 900 to 4000 cm−1. Vibrational assignments for R125 are revised by comparison of previous and current experimental data with ab initio calculations at both the MP2/6-311+(d,p) and B3LYP/TZV+(3df,3p) levels of theory. High resolution FTIR spectra were recorded at room temperature and in an enclosive flow cell at a rotational temperature of 140 K. The cold spectrum was sufficiently resolved to enable rovibrational analyses of the overlapping ν4 (1200.7341 cm−1) and ν13 (1223.3 cm−1) bands, which have a/c hybrid and b-type character, respectively. Ground state combination differences were used to confirm assignment of 2375 lines to ν4 (Jmax = 86, Ka max = 50) and 2921 lines to ν13 (Jmax = 60, Ka max = 54). Effective rotational and centrifugal distortion constants were determined for ν4, and the polarization ratio was found to be . Severe Coriolis perturbations prevent any satisfactory fit to the ν13 band. 相似文献
785.
IvanaCarrizo SergioFavier 《分析论及其应用》2003,19(3):238-254
In this work two aspects of theory of frames are presented: a side necessary condition on irregular wavelet frames is obtained, another perturbation of wavelet and Gabor frames is considered. Specifically,we present the results obtained on frame stability when one disturbs the mother of wavelet frame, or the parameter of dilatation, and in Gabor frames when the generating function or the parameter of translation are perturbed. In all cases we work without demanding compactness of the support, neither on the generating function, nor on its Fourier transform. 相似文献
786.
Ivana Alexandrova 《偏微分方程通讯》2013,38(10):1505-1535
ABSTRACT We consider scattering by general compactly supported semi-classical perturbations of the Euclidean Laplace-Beltrami operator. We show that if the suitably cut-off resolvent quantizes a Lagrangian relation on the product cotangent bundle, the scattering amplitude quantizes the natural scattering relation. In the case when the resolvent is tempered, which is true at non-trapping energies or at trapping energies under some non-resonance assumptions, and when we work microlocally near a non-trapped ray, our result implies that the scattering amplitude defines a semiclassical Fourier integral operator associated to the scattering relation in a neighborhood of that ray. Compared to previous work, we allow this relation to have more general geometric structure. 相似文献
787.
Stefan Gollowitzer Bernard Gendron Ivana Ljubić 《Computational Optimization and Applications》2013,55(3):647-674
We consider a network design problem that arises in the cost-optimal design of last mile telecommunication networks. It extends the Connected Facility Location problem by introducing capacities on the facilities and links of the networks. It combines aspects of the capacitated network design problem and the single-source capacitated facility location problem. We refer to it as the Capacitated Connected Facility Location Problem. We develop a basic integer programming model based on single-commodity flows. Based on valid inequalities for the capacitated network design problem and the single-source capacitated facility location problem we derive several (new) classes of valid inequalities for the Capacitated Connected Facility Location Problem including cut set inequalities, cover inequalities and combinations thereof. We use them in a branch-and-cut framework and show their applicability and efficacy on a set of real-world instances. 相似文献
788.
We consider a new combinatorial optimization problem that combines network design and facility location aspects. Given a graph with two types of customers and two technologies that can be installed on the edges, the objective is to find a minimum cost subtree connecting all customers while the primary customers are served by a primary subtree that is embedded into the secondary subtree. In addition, besides fixed link installation costs, facility opening costs, associated to each node where primary and secondary subtree connect, have to be paid. The problem is called the Two Level Network Design Problem with Transition Facilities (TLNDF). 相似文献
789.
Ivana Zrinski Sanja Martinez Astrid Ortner Anchalee Samphao Janez Zavašnik Kurt Kalcher Eda Mehmeti 《Electroanalysis》2021,33(5):1325-1332
The electrocatalytic oxidation of rapamycin, one of the most studied immunosuppressant, cancer-preventing drug, is investigated for the first time on the surface of the modified carbon paste electrode prepared by incorporating multi-walled carbon nanotubes (MWCNTs) and conductive polymer pyrrole using differential pulse voltammetry (DPV). Rapamycin exhibited a well-defined oxidation peak at +1.1 V (versus Ag/AgCl) in Briton Robinson buffer solution with a pH 4.0. Effect of the most important experimental parameters was optimized and obtained signals are linear to the concentration of rapamycin in the range from 0.1 to 20 μM with 0.06 μM limit of detection. The repeatability is calculated as ±2 % and the reproducibility as ±5 %. The possible interfering compounds were tested showing negligible effect and the sensor was successfully applied for the determination of rapamycin in commercial pharmaceutical formulations with obtained recoveries in the range from 98 % to 102 %. 相似文献
790.
Dijana Pešić Ivana Ozimec Landek Ana Čikoš Biserka Metelko Vesna Gabelica Barbara Stanić Mladen Merćep Milan Mesić 《Journal of heterocyclic chemistry》2007,44(5):1129-1133