Na[Li(NH2BH3)2]--the first mixed-cation amidoborane with unusual crystal structure

We describe the successful synthesis of the first mixed-cation (pseudoternary) amidoborane, Na[Li(NH(2)BH(3))(2)], with theoretical hydrogen capacity of 11.1 wt%. Na[Li(NH(2)BH(3))(2)] crystallizes triclinic (P1) with a = 5.0197(4) ?, b = 7.1203(7) ?, c = 8.9198(9) ?, α = 103.003(6)°, β = 102.200(5)°, γ = 103.575(5)°, and V = 289.98(5) ?(3) (Z = 2), as additionally confirmed by Density Functional Theory calculations. Its crystal structure is topologically different from those of its orthorhombic LiNH(2)BH(3) and NaNH(2)BH(3) constituents, with distinctly different coordination spheres of Li (3 N atoms and 1 hydride anion) and Na (6 hydride anions). Na[Li(NH(2)BH(3))(2)], which may be viewed as a product of a Lewis acid (LiNH(2)BH(3))/Lewis base (NaNH(2)BH(3)) reaction, is an important candidate for a novel lightweight hydrogen storage material. The title material decomposes at low temperature (with onset at 75 °C, 6.0% mass loss up to 110 °C, and an additional 3.0% up to 200 °C) while evolving hydrogen contaminated with ammonia.     

High-throughput age synchronisation of Caenorhabditis elegans

We present a passive microfluidic strategy for sorting adult C. elegans nematodes on the basis of age and size. The separation mechanism takes advantage of phenotypic differences between 'adult' and 'juvenile' organisms and their behaviour in microfluidic architectures. In brief, the microfluidic device allows worms to sort themselves in a passive manner.     

Comprehensive Characterisation of the Ketoprofen-β-Cyclodextrin Inclusion Complex Using X-ray Techniques and NMR Spectroscopy

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an aqueous solution, it was found that in the samples obtained by methods 1 and 2, there were large excesses of β-CD in relation to KP, 10 and 75 times, respectively, while the sample obtained by method 3 contained equimolar amounts of β-CD and KP. NMR results indicated that KP/β-CD inclusion complexes were formed and the estimated binding constants were approximately 2400 M⁻¹, showing that KP is quite strongly associated with β-CD. On the other hand, the X-ray single-crystal technique in the solid state revealed that the (S)-KP/β-CD inclusion complex with a stoichiometry of 2:2 was obtained as a result of heating-under-reflux, for which the crystal and molecular structure were examined. Among the methods used for the preparation of the KP/β-CD complex, only method 3 is suitable.     

A Quasi-Newton Penalty Barrier Method for Convex Minimization Problems

We describe an infeasible interior point algorithm for convex minimization problems. The method uses quasi-Newton techniques for approximating the second derivatives and providing superlinear convergence. We propose a new feasibility control of the iterates by introducing shift variables and by penalizing them in the barrier problem. We prove global convergence under standard conditions on the problem data, without any assumption on the behavior of the algorithm.     

Distinguishable equivalent particles with symmetrized wave functions

The quantum formalism ofdistinguishable, yetequivalent particles (with symmetric or antisymmetric wave functions) is here worked out. The result is an entirely explicit formulation of the way in which classical mechanics emerges from quantum mechanics for such particles. Distinguishability is achieved at the cost of dynamical precision; the two are, in fact, complementary.Research sponsored in part by the Air Force Office of Scientific Research, Office of Aerospace Research, United States Air Force, under AFOSR Grant No. 557–67.     

Über peroxoverbindungen XI. Nichtradikalische substitions- und redoxreaktionen des bis(trimethylsilyl)peroxyds

The reactivity of bis(trimethylsilyl)peroxide with a variety of nucleophilic, electrophilic, oxidizing, and reducing agents has been investigated.     

Localized surface modes and resonances for vicinal surfaces: The (117) face of fcc crystals

Considering the (117) face of an fcc crystal, the dispersion relations of localized surface modes and resonances have been calculated using the method of generating coefficients of Green functions. The force between atoms are limited to the central force between the nearest neighbours. In the direction of propagation orthogonal to a step, for each wavevector value, a localized surface mode and two resonances have been found. Their polarization amplitude and width have been calculated. It is shown that these results can be qualitatively understood by folding three times the dispersion relation of the (001) face which is the crystallographic plane of the terrace. In the direction parallel to the step, the dispersion relations are obtained by the superposition of the sagittal and transverse dispersion relation of the (001) face. The (117) configuration introduces a coupling between these two polarizations and some resonances appear. A general rule which enables one to predict qualitatively the shape of the dispersion relation for any vicinal surface of type (11m) is expressed.