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81.
82.
An ion-pair liquid chromatographic assay was developed and validated for the determination of ceftriaxone in cerebrospinal fluid. Chromatographic separation was achieved on a C18 column (125 x 4 mm, 5 microm) with detection at 270 nm, a 1 mL/min flow rate and a 50 microL loop. The mobile phase consisted of 300 mL acetonitrile, 50 mL 0.1M phosphate buffer (pH 7.4), 3.2 g tetrabutylammonium bromide as the ion-pairing agent, and dilution with distilled deionized water to 1 L. Cephradine was used as the internal standard. The assay was linear for ceftriaxone concentrations of 0.5-50 microg/mL. The coefficients of variation for precision were <4.61%. The accuracy ranged from 96.07 to 102.42%. The detection and quantitation limits were 0.019 and 0.065 microg/mL, respectively. This method was used to quantify ceftriaxone in the cerebrospinal fluid of children with meningitis. The results showed that the method described here is useful for the determination of ceftriaxone in cerebrospinal fluid. 相似文献
83.
The symmetric derivatives of pyridoxal with thiocarbohydrazide and carbohydrazide, and the asymmetric derivatives of pyridoxal and salicylaldehyde with the same hydrazides have been synthesized and their analytical potential for spectrophotometric and kinetic fluorimetric determination of metal ions was studied. Gallium(III) and PyMAU(1,3-bis{[4-(2-methyl-3-hydroxy-5-hydroxymethyl)pyridyl]methyleneaminourea at pH = 4.2 form a complex with a single absorption maximum at 425 nm, which can be extracted into cyclohexanone in the presence of a controlled amount of sodium perchlorate. The extract has maximum absorbance at 435 nm. Both systems can be used for determining gallium. The optimal range of gallium concentration for measurement in a 1-cm cell is 0.5-1.25 gmg/ml for the procedure in homogeneous medium ((425) = 3.76 x 10(4).mole(-1).cm(-1)) and 0.25-1.25 mug/ml for the extraction procedure ((435) = 5.30 x 10(4) 1.mole(-1).cm(-1). The latter procedure has been applied to the determination of gallium in alloys and fly-ash. 相似文献
84.
L. A. Schuch D. J. R. Nordemann A. Zago D. L. Dallpai J. M. Godoy B. Pecequilo 《Journal of Radioanalytical and Nuclear Chemistry》1994,177(1):101-106
Various types of soil samples were collected in the southern part of Brazil, with depth intervals of 5 cm, down to 50 cm, using a specially designed sampler. Pedological analysis of these soils were performed. Nuclear activities of137Cs (expressed in Bq m–2) and radioactive natural element (226Ra,228Ra and40K) concentrations were determined by low background gamma-ray spectrometry.137Cs concentrations were correlated with radioactive natural element concentrations and pedological, climatological and geographic parameters related to the soil samples collected. 相似文献
85.
Godoy Netto Adelino V. Frem Regina C.G. Mauro Antonio E. Santos Regina H.A. Zoia Jussara R. 《Transition Metal Chemistry》2002,27(3):279-283
Mononuclear palladium(II) complexes containing both pyrazole-type ligands and thiocyanate, of general formula [Pd(SCN)2(L)2] {L = pyrazole (HPz) and 1-phenyl-3-methylpyrazole (phmPz)} have been prepared and characterized by elemental analysis, i.r. and n.m.r. spectroscopy and by single crystal X-ray diffraction methods. The Pd atom in these structures lies on the crystallographic inversion center; in a square-planar coordination geometry made by two sulfur and two nitrogen atoms of the ligands, both in trans positions. 相似文献
86.
Yacine Chitour Mauricio Godoy Molina Petri Kokkonen Irina Markina 《Journal of Geometric Analysis》2016,26(4):2542-2562
We study the control system of a Riemannian manifold M of dimension n rolling on the sphere \(S^n\). The controllability of this system is described in terms of the holonomy of a vector bundle connection which, we prove, is isomorphic to the Riemannian holonomy group of the cone C(M) of M. Using Berger’s list, we reduce the possible holonomies to a few families. In particular, we focus on the cases where the holonomy is the unitary and the symplectic group. In the first case, using the rolling formalism, we construct explicitly a Sasakian structure on M; and in the second case, we construct a 3-Sasakian structure on M. 相似文献
87.
Freddy Navarro Rodrigo Segura Fernando Godoy Angel A. Martí Carolina Mascayano Maria J. Aguirre Erick Flores Jaime Pizarro 《Electroanalysis》2023,35(4):e202200357
The interactions of zopiclone with electrochemically reduced graphene oxide (rGO) modified electrode were examined. A comparison of GC/rGO and glassy carbon electrode (GC) by electrochemical impedance spectroscopy and scanning electrochemical microscopy (SECM) shows that the modified surface is much less conductive than GC. The role of rGO is to act as a site of specific adsorption of the analyte. Molecular dynamics showed that the monoanionic form of zopiclone presents more interactions with defects of rGO. The analytical methodology allowed obtaining a linearity of 10–130 μg L−1, with a limit of detection of 2.14 μg L−1 using SWAdSV at pH 10.0. 相似文献
88.
We introduce polynomials $B^n_{k}(\boldmath{x};\omega|q)$ of total degree n, where $\boldmath{k} = (k_1,\ldots,k_d)\in\mathbb N_0^d, \; 0\le k_1+\ldots+k_d\le n$ , and $\boldmath{x}=(x_1,x_2,\ldots,x_d)\in\mathbb R^d$ , depending on two parameters q and ω, which generalize the multivariate classical and discrete Bernstein polynomials. For ω=0, we obtain an extension of univariate q-Bernstein polynomials, introduced by Phillips (Ann Numer Math 4:511–518, 1997). Basic properties of the new polynomials are given, including recurrence relations, q-differentiation rules and de Casteljau algorithm. For the case d=2, connections between $B^n_{k}(\boldmath{x};\omega|q)$ and bivariate orthogonal big q-Jacobi polynomials—introduced recently by the first two authors—are given, with the connection coefficients being expressed in terms of bivariate q-Hahn polynomials. As limiting forms of these relations, we give connections between bivariate q-Bernstein and Dunkl’s (little) q-Jacobi polynomials (SIAM J Algebr Discrete Methods 1:137–151, 1980), as well as between bivariate discrete Bernstein and Hahn polynomials. 相似文献
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90.