Rotational motion in LiBH4/LiI solid solutions

We investigated the localized rotational diffusion of the (BH(4))(-) anions in LiBH(4)/LiI solid solutions by means of quasielastic and inelastic neutron scattering. The (BH(4))(-) motions are thermally activated and characterized by activation energies in the order of 40 meV. Typical dwell times between jumps are in the picosecond range at temperatures of about 200 K. The motion is dominated by 90° reorientations around the 4-fold symmetry axis of the tetrahedraly shaped (BH(4))(-) ions. As compared to the pure system, the presence of iodide markedly reduces activation energies and increases the rotational frequencies by more than a factor of 100. The addition of iodide lowers the transition temperature, stabilizing the disordered high temperature phase well below room temperature.     

Synthesis of 1,4-diaryl[60]fullerenes by bis-hydroarylation of C60 and their use in solution-processable, thin-film organic photovoltaic cells

An AlCl₃-mediated Friedel-Crafts reaction of arenes with C₆₀ affords two-fold hydroarylated compounds, C₆₀Ar₂H₂, which upon deprotonation with ^tBuOK and oxidation with CuBr·SMe₂ yield 1,4-diaryl[60]fullerenes, C₆₀Ar₂ (Ar = Ph, 4-Me-C₆H₄, 3,4-Me₂-C₆H₃, and 4-Ph-C₆H₄) in good yield. A solution-processed, thin-film organic photovoltaic device using C₆₀(4-PhC₆H₄)₂ as electron acceptor material showed a 2.3% power conversion efficiency.     

Synergistic inhibition of malignant melanoma proliferation by melphalan combined with ultrasound and microbubbles

The cavitational effects of ultrasound (US) exposure induce transient pores on the cell membrane (sonoporation). Sonoporation have been applied in the field of cancer therapy by promoting delivery of extracellular molecules such as drugs and genes into cytoplasm. In addition, it is known that using US together with microbubbles (MB) elevates permeability of these agents. In this study, by applying the US-MB strategy for melanoma chemotherapy, we evaluated the antitumor effect of melphalan combined with US-MB on a melanoma cell line (C32) in vitro and in vivo. The in vitro cytotoxic effect of the melphalan with US-MB was greater than that of melphalan alone or melphalan in combination with US. In vivo experiments using xenografts, intratumoral injection of melphalan and MB with US exposure led to a greater degree of tumor regression than did the intratumoral injection of the melphalan alone or melphalan in combination with US. These results suggest that US-MB promotes the antitumor effect of melphalan by increasing delivery of molecules into cells and that this strategy may become an effective method of adjuvant therapy against malignant melanoma.     

Combustion wave propagation and detonation initiation in the vicinity of closed-tube end walls

There are not many studies on DDT with no obstacles and the initiation of DDT near the end of a closed tube. Therefore in the present study we experimentally investigate the mechanism of the combustion wave transition to a detonation wave when there are no obstacles. In particular, we show that a local explosion near the tube wall is necessary for the initiation of a detonation. Parameters that we varied are the wall configuration, distance between the ignition point and the wall, and initial filling pressure. The combustion waves and the compression waves are visualized using the Schlieren optical system. From the results, we found it is necessary for the combustion wave to reach four walls so that the detonation could be initiated by the local explosion. In the conditions of the present experiment, we exhibited that the local explosion did not occur in the vicinity of a single wall and four orthogonal walls; instead, the local explosion occurred in a situation with five orthogonal walls. The time of the local explosion and the detonation initiation is 2.6 ± 1.1 and 2.0 ± 0.1 times the characteristic time for the combustion wave to propagate hemispherically from an ignitor and reach the four walls.     

Synthesis of several cyclopalladated biacetylmonoxime arylhydrazones

Palladium(II) complexes of biacetylmonoxime arylhydrazones (HL, aryl = phenyl, o-, m-, and p-tolyl, p-chloro- and p-nitrophenyl) and biacetylmonoxime N′-methyl-phenylhydrazone (HL′) have been prepared and characterized. The hydrazomines, HL and HL′, are coordinated through oxime- and hydrazone-nitrogen atoms as a bidentate ligand in the complexes [PdX₂(HL or HL′)] (X = halogen atom) formed under neutral conditions. Under basic conditions the deprotonated complexes [PdX(L or L′)] are obtained. Deprotonation occurs at the oxime group of HL′ and the ligand remains coordinated through oxime- and hydrazone-nitrogen atoms. The other hydrazoximes (HL) are cyclopalladated at the ortho position of the benzene rings and act as an NNC terdentate ligand in the deprotonated complexes [PdXL].     

Catalytic and stereoselective glycosylation with glycosyl N-trichloroacetylcarbamate

Catalytic and stereoselective glycosylation efficiently proceeded by activating a glycosyl N-trichloroacetylcarbamate with a catalytic amount of Lewis acids in the presence of a glycosyl acceptor and molecular sieves 5 Å. Catalytic and one-pot dehydrative glycosylation of a 1-hydroxy carbohydrate was also performed stereoselectively by the reaction with trichloroacetyl isocyanate followed by activation with a catalytic amount of activators.     

Low-temperature heat capacities and thermodynamic properties of rare-earth triisothiocyanate hydrates (III) —Sm(NCS)3 · 6H2O, Gd(NCS)3 · 6H20, Yb(NCS)3 · 6H20 and Y(NCS)3 · 6H20

The heat capacities of four RE isothiocyanate hydrates, Sm(NCS)₃, · 6H₂0, Gd(NCS)₃ · 6H₂0, Yb(NCS)₃, · 6H₂O and Y(NCS)₃, · 6H₂0, have been measured from 13 to 300 K with a fully-automated adiabatic calorimeter. No obvious thermal anomaly was observed for the above-mentioned compounds in the experimental temperature ranges. The polynomial equations for calculating the heat capacities of the four compounds in the range of 13–300 K were obtained by the least-squares fitting based on the experimentalC _P, data. TheC _P, values below 13 K were estimated by using the Debye-Einstein heat capacity functions. The standard molar thermodynamic functions were calculated from 0 to 300 K. Gibbs energies of formation were also calculated. Project supported by the National Natural Science Foundation of China.     

Improvement in stability of LiMn2O4 thin-film electrodes by oxygen-plasma irradiation to precursor gel

LiMn₂O₄ thin-film electrodes were prepared by the sol?Cgel method combined with oxygen-plasma irradiation. Oxygen plasma with a power of 10 or 90?W was irradiated to the precursor thin film prepared from lithium acetate, manganese acetate tetrahydrate and polyvinylpyrrolidone on a Pt plate, and then it was fired at 723 or 973?K. X-ray diffraction and Raman measurements indicated that oxygen-plasma irradiation was effective to increase the crystallinity of the resulting LiMn₂O₄. Atomic force microscope observation showed that the particle size of LiMn₂O₄ in the resulting thin-film electrode was decreased and homogeneous distribution of LiMn₂O₄ particles was achieved. Oxidation of the electrolyte at higher potentials was suppressed and capacity retention at 328?K was dramatically improved for the LiMn₂O₄ thin-film electrode obtained at 973?K. The improved electrochemical stability is ascribed to the elimination of organic materials from precursor by oxygen-plasma irradiation.