Influence de la teneur en halogene sur les proprietes cathodochromiques des sodalites

The influence of the preparative methods upon the number of vacancies in sodalites Na_4-x(AlSiO₄)₃Br_1-x (0.07 ? x ? 0.86) was investigated. A relation has been found between the bromine content and the number of optically erasable F centers induced by an electron beam. Conversely to some previous hypotheses it is possible to conclude that the halogen is the electron donor.     

Synthesis and characterization of an N-acylsulfonamide inhibitor of human asparagine synthetase

[structure: see text] The synthesis of N-acylsulfonamide 6, which is an analogue of beta-aspartyl-AMP, is described. This compound appears to be the first and only potent inhibitor of human asparagine synthetase that has been described to date. The N-acylsulfonamide 6 exhibits slow-onset inhibition kinetics, with a K(i) of 728 nM. Preparation and characterization of two additional N-acylsulfonamide analogues has also demonstrated the importance of hydrogen-bonding interactions in the recognition of the AS inhibitor with the enzyme. These observations provide the basis for the discovery of new compounds with application in the treatment of drug-resistant leukemia.     

A note on the determination of the fundamental frequency of vibration of rectangular and circular plates supporting masses distributed over a finite area

The title problem is solved in an approximate fashion using polynomial coordinate functions and Galerkin's method. The present approach is applicable when the mass is distributed over a rectangular subdomain in the case of a rectangular plate. For a circular plate the mass is applied over a concentric circular region.     

Vibration of simply-supported plates of arbitrary shape carrying concentrated masses and subjected to a hydrostatic state of in-plane stresses

The title problem is solved by using a conformal mapping-variational method. The calculated eigenvalues are in good agreement with those obtained by using a finite element approach. The problem is of practical importance since the knowledge of the dynamic behavior of odd-shaped plates is of great interest in the design of electronic packages containing printed circuit boards.     

Determination of the second natural frequency of simply-supported regular polygonal plates

The conformal mapping-variational method is used to solve the title problem. The calculated frequency coefficients are in good agreement with those obtained by using a well known finite element computer system (STRUDL), in the case of an equilateral plate.     

Synthesis,spectral study and thermal behaviour of some 4-(O-acetyl)-glycopyranosylamino-5-nitrosopyrimidine derivatives

The syntheses, specific optical rotations, spectral features (¹H-NMR, UV-visible and IR spectroscopy) and thermal characterization of seven 4-(O-acetyl)-glycopyranosylamino-5-nitrosopyrimidine derivatives are reported. With IR spectroscopy, the starting of the pyrolytic decomposition mechanism of the compounds was established.     

A simple approximate method for the solution of the Helmholtz equation in the case of rectangular,non-homogeneous domains

The dynamic behavior of non-homogeneous continuous media is of interest in many fields, from geophysics to everyday mechanical engineering systems and especially in bioengineering.Discontinuous types of non-homogeneities are considered in this paper and it is shown that the Ritz method is convenient for this complicated type of structural element.     

Estimation and filtering on a doubly stochastic poisson process

An explicit formula for the characteristic function of a doubly stochastic Poisson process is derived in this paper by means of the harmonic decomposition of its intensity function that we suppose to be Gaussian. The statistical moments are then obtained, as well as the sample function density of the process. These results are applied to estimate the parameters of several well-known processes. Finally, a linear filtering procedure for the intensity function is developed and the algorithm is implemented by computers.     

Metal complexes of two 7-oxo-vic-triazolo[4,5-d]pyrimidine derivatives

Seven Hg(II), Pd(II), Cu(II), and Ag(I) complexes of two 7-oxo-vic-triazolo[4,5-d]pyrimidine derivatives have been obtained. The complexes were characterized by spectroscopic studies (IR,¹H-NMR and UV-visible) and magnetic measurements. On the basis of these data both the structure of the complexes and the coordination positions of the pyrimidinic ligands have been proposed. Likewise, the thermal behaviour of the complexes has also been studied.

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Metall-Komplexe von zwei 7-Oxo-vic-triazolo[4,5-d]pyrimidin-Derivaten

Zusammenfassung Sieben Hg(II)-, Pd(II)-, Cu(II)- und Ag(I)-Komplexe von zwei 7-Oxo-vic-triazolo[4,5-d]pyrimidin-Derivaten wurden hergestellt. Die Komplexe wurden durch die Daten der elementaren Analyse, spektroskopische Studien (IR,¹H-NMR und UV-Vis.) und magnetische Messungen charakterisiert. Auf der Basis dieser Daten wurden die Strukturen der Komplexe und die Koordinationsstelle der Pyrimidin-Liganden bestimmt. Das thermische Verhalten der Komplexe wurde ebenfalls untersucht.