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排序方式: 共有230条查询结果,搜索用时 15 毫秒
61.
62.
Maria M. Orive Blanca Gallo Rosa M. Alonso Francisca Vicente Jean C. Viré Gaston J. Patriarche 《Mikrochimica acta》1989,97(3-4):181-190
The acid-base behaviour of midazolam, a psychotropic drug derived from imidazobenzodiazepine family, has been studied spectro-photometrically. This compound hydrolyzes at pH values lower than 4. Reversible cleavage of the azomethine bond takes place and the open-ring compound is in equilibrium with the closed-ring compound (protonated form of the parent drug). Absorbance-time data (measured at 225 nm and for different pH values) have been evaluated by a pseudo-first order logarithmic approach, leading to different apparent kinetic constants, depending on pH and temperature. A simple mechanism of hydrolysis, corresponding to fast protonation and slow hydrolysis with opening of the ring is in good agreement with the kinetic results. From data obtained at pH values greater than 4, the deprotonation constant of the nitrogen atom at position 2 of the imidazole ring has been calculated and a pKa value of 5.50 ± 0.05 obtained. In addition, a Spectrophotometric method has been developed which allows the determination of midazolam at concentrations from 1.23 × 10–6
M to 3.38 × 10–5
M. This method has been applied to a pharmaceutical formulation midazolam; the Dormicum error, in terms of relative standard deviation, was lower than 1.5%. 相似文献
63.
Gaston Casanova 《Advances in Applied Clifford Algebras》1999,9(2):215-219
If an algebraic equation onIR admits real roots it admits hyperbolic roots which are elements of the set (x 0 + εy 0) where ε is a Clifford number having a square equal to 1. The equation can have hyperbolic or real roots
[((a1 + a2 ))/2] + e[((a1 - a2 ))/2]{{(a_1 + a_2 )} \over 2} + \varepsilon {{(a_1 - a_2 )} \over 2} 相似文献
64.
The alkylation of Δ4-thiazoline-2-thiones under phase transfer catalysis conditions leads to the corresponding thioethers in good yields. The oxidation of 2-alkylthiazoles with m-chloroperbenzoic acid leads to the corresponding sulfines or sulfones depending on experimental conditions in yields of about 80-90%. The characteristic gle, tlc, ir, 1H nmr and ms data are reported for most of the compounds studied. 相似文献
65.
The matrix elements of the total Hamiltonian between a multiconfigurational SCF wave function and some well-defined linear combinations of excited Slater determinants are equal to zero. By means of this generalized Brillouin theorem it is possible to estimate the improvements to be expected from a subsequent configuration-interaction treatment. The expression of the effective potential for the orbitals can be also derived in the frame of a given multiconfigurational theory. As an example, the case of the CMC-SCF method recently suggested [9] is examined. 相似文献
66.
Study of heteroaromatic radicals. Part XV .
67.
Gustavo Cabrera-Barjas Aleksandra Nesic Gaston Bravo-Arrepol Saddys Rodríguez-Llamazares Oscar Valds Aparna Banerjee Johanna Castao Cdric Delattre 《Molecules (Basel, Switzerland)》2021,26(24)
This study investigated the biocomposite pectin films enriched with murta (Ugni molinae T.) seed polyphenolic extract and reinforced by chitin nanofiber. The structural, morphological, mechanical, barrier, colorimetric, and antioxidant activity of films were evaluated. The obtained data clearly demonstrated that the addition of murta seed extract and the high load of chitin nanofibers (50%) provided more cohesive and dense morphology of films and improved the mechanical resistance and water vapor barrier in comparison to the control pectin film. The antioxidant activity ranged between 71% and 86%, depending on the film formulation and concentration of chitin nanofibers. The presented results highlight the potential use of chitin nanofibers and murta seed extract in the pectin matrix to be applied in functional food coatings and packaging, as a sustainable solution. 相似文献
68.
Hui-Sheng Ding Jin Liang Gaston M. N’Guérékata Ti-Jun Xiao 《Nonlinear Analysis: Theory, Methods & Applications》2008
This paper is concerned with neutral nonlinear delay integral equations. We establish an existence theorem for positive almost automorphic solutions to the equations, which extend some existing results even in the case of almost periodicity. Some examples are given to illustrate our results. 相似文献
69.
Gaston Casanova 《Advances in Applied Clifford Algebras》2008,18(2):139-142
We generalize a property of a circle concerning the power of a point. 相似文献
70.
In this paper we give some sufficient conditions for ensuring the existence and uniqueness of a mild almost automorphic solution to a second-order semilinear evolution equation in a Banach space. We also present some properties of the (new) notion of a uniform spectrum of bounded functions. 相似文献
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