Quantitation of sunitinib,an oral multitarget tyrosine kinase inhibitor,and its metabolite in urine samples by nonaqueous capillary electrophoresis time of flight mass spectrometry

A rapid, sensitive, and specific method was developed and validated using a nonaqueous‐capillary electrophoresis method with TOF‐MS for determination of sunitinib and N‐desethyl sunitinib in human urine. In order to avoid ionic suppression a urine samples dilution with methanol 1:10 previous step was used. This was the only treatment step to urine samples before the injection. Despite this dilution of the urine, the detection limit was as low as 0.07 mg/L for sunitinib and 0.15 mg/L for N‐desethyl sunitinib. Separation of compounds was achieved with a mixture of 5 mM ammonium formate in methanol. The calibration curves were linear over the range of 0.5–50.0 mg/L for the two analyzed compounds. The within‐run and between‐run precisions were within 5%, while the accuracy ranged from 96.0 to 100.4%. This method can be used in routine clinical practice to monitor sunitinib and N‐desethyl sunitinib drugs in the urine of cancer patients treated with once daily administration.     

New variational principles in plasticity and their application to composite materials

I , a variational method for bounding the effective properties of nonlinear composites with isotropic phases, proposed recently by ponte castañeda (J. Mech. Phys. Solids 39, 45, 1991), is given full variational principle status. Two dual versions of the new variational principle are presented and their equivalence to each other, and to the classical variational principles, is demonstrated. The variational principles are used to determine bounds and estimates for the effective energy functions of nonlinear composites with prescribed volume fractions in the context of the deformation theory of plasticity. The classical bounds of Voigt and Reuss for completely anisotropic composites are recovered from the new variational principles and are given alternative, simpler forms. Also, use of a novel identity allows the determination of simpler forms for nonlinear Hashin-Shtrikman bounds, and estimates, for isotropic, particle-reinforced composites, as well as for transversely isotropic, fiber-reinforced composites. Additionally, third-order bounds of the Beran type are determined for the first time for nonlinear composites. The question of the optimality of these bounds is discussed briefly.     

Conformations of diester triphenylphosphonium ylides with an ylidic ester or keto and ester ylidic groups

The structures of three related keto diester and diester ylides, namely diethyl 3‐oxo‐2‐(triphenylphosphoranylidene)glutarate, C₂₇H₂₇O₅P, (I), diethyl 3‐oxo‐2‐(triphenylphosphoranylidene)glutarate acetic acid monosolvate, C₂₇H₂₇O₅P·C₂H₄O₂, (II), and diethyl 2‐(triphenylphosphoranylidene)succinate, C₂₆H₂₇O₄P, (III), are presented. The syn‐keto anti‐ester conformations in the crystalline keto diesters are governed by electronic delocalization between the P—C and ylidic bonds and an acyl group, and by intra‐ and intermolecular interactions. There are also intramolecular attractive and repulsive interactions of different types (C—H...O and C—H...π) controlling the molecular conformations. The mono‐ylidic diester (III) has an anti‐ester conformation, while those for (I) and (II) are related to pyrolytic formation of acetylene derivatives. The terminal nonylidic ester group in (I) was disordered over two sets of almost equally populated positions.     

SiO2 Xerogel: A Suitable Inert Support for Microbial Growth

A silica xerogel was prepared at pH 2 by the hydrolysis-condensation reactions of the sol-gel method. Silica xerogel was used as a support for the growth of two filamentous fungi: Aspergillus niger ATCC 9642 and Phanerochaete chrysosporium A594. In both cases, an apparent abundant mycelia growth (5.5 mg biomass/g dry xerogel and 4.7 mg biomass/g dry xerogel respectively) was observed. A phase of rapid consumption of glucose which lasted until 96 h of culture with sugar consumption rate of 0.075 mg sugar/g support h and 0.042 mg sugar/g support h respectively, was also observed. Scanning electron microscopy (SEM) showed a superficial colonisation of both strains even in the occasional imperfections and crevices of the xerogel. This novel application of sol-gel metallic oxide systems suggests the potential use of an inert and versatile support which could be valuable, for example for solid state fermentation fundamental studies.     

Oligo (p -phenylene)s substituted with long alkoxy chains I. Thermotropic liquid crystalline properties and UV absorption/emission characteristics

A series of linear oligo (p-phenylene)s containing three, five and seven phenylene groups, modified with short lateral and long terminal alkoxy chains, were synthesized via Palladium complex-catalysed cross-coupling reactions. The thermotropic liquid crystalline and UV absorption/emission properties of these compounds were studied. It was observed that tri (p -phenylene)s develop a rich mesomorphism including tilted smectic type mesophases (SmC and SmF/SmI) and the nematic phase, whereas penta- and hepta-(p-phenylene)s substituted with short lateral chains develop only the nematic phase. From these observations it is clear that the short lateral chains hinder the layered molecular packing typical of smectic phases and promote the formation of the less ordered liquid-like nematic phase. Mesophases appeared at lower temperatures when longer end chains were used. The optical properties studied by UV-Vis and emission spectroscopy indicate that these systems are promising candidates for blue-emitting layers in electroluminescent devices.     

A Common Conformation of Stabilized Triphenyl Phosphonium Ylidic Diesters with Bulky Alkoxy Groups

The phosphonium ylidic diesters, methyl and ethyl isopropyl and, methyl and ethyl t-butyl triphenylphosphoranylidene malonates, 1a,b and 2a,b , respectively, have the syn-anti conformation in solution, as in the crystal, and the bulkier alkoxy group is oriented towards phosphorus. The ¹ H NMR spectra show that in 1a,b , the isopropyl group is oriented towards the face of a phenyl group, consistent with π shielding in the ¹ H signals, and examination of the ¹ H coupled ¹³ C NMR spectra allows assignment of the acyl carbon signals. Computed bond lengths and angles for isolated molecules are similar to those in the crystal, and the geometry and the NMR spectra indicate extensive ylidic resonance. Estimated partial atomic charges on the ester oxygens are more negative when they are oriented towards, rather than away from, phosphorus.     

The importance of glyceraldehyde radiolysis in chemical evolution

Studies in chemical evolution are intended to demonstrate how compounds of biological importance are generated from substances that could have been found in abiotic conditions on the primitive Earth or in extraterrestrial environments. In this context, the aim of the present work was to examine the behavior of dl-glyceraldehyde in both aqueous solution and solid samples under gamma irradiation. We irradiated dl-glyceraldehyde at different doses and temperatures with a gamma source; even at low doses and temperature (77 K), free radicals were detected. Among the products formed were ethylene glycol and glycolaldehyde. Some sugar-like compounds were also detected.

     

Photoconductivity,photoluminescence and optical Kerr nonlinear effects in zinc oxide films containing chromium nanoclusters

Chromium doped zinc oxide thin solid films were deposited on soda–lime glass substrates. The photoconductivity of the material and its influence on the optical behavior was evaluated. A non-alkoxide sol–gel synthesis approach was used for the preparation of the samples. An enhancement of the photoluminescence response exhibited by the resulting photoconductive films with embedded chromium nanoclusters is presented. The modification in the photoconduction induced by a 445 nm wavelength was measured and then associated with the participation of the optical absorptive response. In order to investigate the third order optical nonlinearities of the samples, a standard time-resolved Optical Kerr Gate configuration with 80 fs pulses at 830 nm was used and a quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. We estimate that from the inclusion of Cr nanoclusters into the sample results a strong optical Kerr effect originated by quantum confinement. The large photoluminescence response and the important refractive nonlinearity of the photoconductive samples seem to promise potential applications for the development of multifunctional all-optical nanodevices.     

3‐(Triphenyl­phospho­ranyl­idene)pentane‐2,4‐dione and dieth­yl 2‐(triphenyl­phospho­ranyl­idene)malonate

The title ylides, 3‐(triphenyl­phospho­ranyl­idene)pentane‐2,4‐dione, C₂₃H₂₁O₂P, (I), and diethyl 2‐(triphenyl­phospho­ranyl­idene)malonate, C₂₅H₂₅O₄P, (II), differ in the conformations adopted by their extended ylide moieties. In (I), one carbonyl O atom is syn and the other is anti with respect to the P atom, the ylide group is nearly planar, with a maximum P—C—(C=O) angle of 18.2 (2)°, and the P—C, C—C and C=O bond lengths are consistent with electronic delocalization involving the O atoms. In (II), both carbonyl O atoms are anti and the ester groups are twisted out of the plane of the near trigonal ylide C atom, reducing delocalization, the largest P—C—(C=O) angle being 30.2 (2)°.