Characterization of tin phosphate coatings by CEMS

The structure and chemical state of tin in converted tin phosphate coatings, obtained by a treatment of Zn and Mn phosphate in SnCl₂ solution, were characterized by CEMS. Converted Sn(II) phosphate and adsorbed SnO₂ species were main products in the ≈1/3 top layers of Mn and Zn phosphate coationgs, and metallic tin was occasionally recognized in deeper layers. Tin phosphate layers, coated directly on a steel substrate by RF sputtering of Ar ions, were composed of two kinds of Sn(IV) species.     

Writing of two-dimensional crystal curved lines at the surface of Sm2O3-Bi2O3-B2O3 glass by samarium atom heat processing

Two-dimensional crystal curved lines consisting of the nonlinear optical Sm_xBi_1−xBO₃ phase are fabricated at the surface of 8Sm₂O₃·37Bi₂O₃·55B₂O₃ glass by continuous wave Nd:YAG laser (wavelength: 1064 nm) irradiation (samarium atom heat processing) with a power of ∼0.9 W and a laser scanning speed of 5 μm/s. The curved lines with bending angles of 0-90° or with sine-shapes are written by just changing the laser scanning direction. The polarized micro-Raman scattering spectra for the line after bending are the same as those for the line before bending, indicating that the crystal plane of Sm_xBi_1−xBO₃ crystals to the crystal growth direction might be maintained even after the change in the laser scanning direction. It is found from laser scanning microscope observations that the crystal lines at the surface are swelled out smoothly, giving a height of about 10 μm.     

The adsorption of polyoxyethylated nonylphenol in cyclohexane solution

Summary The adsorption of polyoxyethylated nonylphenol on calcium carbonate and on carbon black in cyclohexane was studied and compared with that in water. The adsorption of this nonionic surfactant in cyclohexane on calcium carbonate showed a monolayer adsorption isotherm and that on carbon black showed a multilayer adsorption isotherm. The adsorption cross sectional area,A, of the surfactant molecule increased with the number of the ethylene oxide units,n, in both cases, and expressed by the equationsA=49.1n ^0.34 for the former case andA=270.n ^0.29 for the later case.When either one of the adsorbent or the solvent is polar and the other is nonpolar, the adsorbed molecules form simple oriented monolayer. When both of the adsorbent and the solvent are polar or nonpolar, however, the adsorption takes place in a complicated form and is delicately affected by the impurity and the balance of the polarity of the surfactant molecule.

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Zusammenfassung Die Adsorption von Polyoxyäthylen-nonylphenol an Calciumcarbonat und Ruß in Zyklohexan wurde untersucht und das Adsorptionsverhalten mit den Ergebnissen von wäßrigen Lösungen verglichen, die im letzten Bericht mitgeteilt sind. Die Adsorption dieser nichtionischen oberflächenaktiven Substanz in Zyklohexan an Calciumcarbonat zeigte eine monomolekulare und an Ruß eine höhermolekulare Adsorptionsisotherme. In beiden Fällen nahm der Adsorptionsquerschnitt,A, des oberflächenaktiven Moleküls mit der Anzahl der Äthylenoxid-Einheiten,n, zu, und es galten folgende Werte:A=49.1 n^0.29 im ersten Fall undA=270.n ^0.34 im letzten Fall.Die adsorbierten Moleküle bilden eine einfach orientierte monomolekulare Schicht, wenn von den beiden Komponenten Adsorbens oder Lösungsmittel eines polar und das andere unpolar ist. Wenn jedoch beide polar oder nichtpolar sind, verläuft die Adsorption komplizierter und wird von den Verunreinigungen und der Bilanz der Polarität empfindlich beeinflußt.

     

Bi(OTf)3-catalyzed 5-exo-trig cyclization via halide activation

Lewis acid activation of allyl halides utilizing Bi(OTf)₃ resulted in cationic cyclization of alkenes with high efficiency. While other Lewis acids could catalyze this process with highly substituted alkenes, bismuth salts demonstrated unique reactivity in come cases. This suggested that bismuth triflate possesses interesting halophilic properties.     

Cobalt‐Catalyzed Transformation of Molecular Dinitrogen into Silylamine under Ambient Reaction Conditions

The first successful example of cobalt‐catalyzed reduction of N₂ with Me₃SiCl and Na as a reductant, under ambient reaction conditions, gives N(SiMe₃)₃, which can be readily converted into NH₃. In this reaction system, 2,2′‐bipyridine (bpy) is found to work as an effective additive to improve substantially the catalytic activity. Co?N₂ complexes bearing three Me₃Si groups as ancillary ligands are considered to work as key reactive species based on DFT calculations. The DFT results also allow the proposal of a detailed reaction pathway for the transformation of N₂ into N(SiMe₃)₃.     

Thermochromic properties of low-melting ionic uranyl isothiocyanate complexes

Temperature-dependent yellow-to-red colour changes of uranyl thiocyanate complexes with 1-alkyl-3-methylimidazolium cations have been studied by different spectroscopic methods and this phenomenon is attributed to changes in the local environment of the uranyl ion, including the coordination number, as well as to cation-anion interactions.     

Open-access and multi-directional electroosmotic flow chip for positioning heterotypic cells

We propose a novel method of cell positioning using electroosmotic flow (EOF) to analyze cell-cell interactions. The EOF chip has an open-to-air configuration, is equipped with four electrodes to induce multi-directional EOF, and allows access of tools for liquid handling and of physical probes for cell measurements. Evaluation of the flow within this chip indicated that it controlled hydrodynamic transport of cells, in terms of both speed and direction. We also evaluated cell viability after EOF application and determined appropriate conditions for cell positioning. Two cells were successively positioned in pocket-like microstructures, one in each micropocket, by controlling the EOF direction. As an experimental demonstration, we observed contact interactions between two individual cells through gap junction channels. The EOF chip should provide ways to elucidate various cell-cell interactions between heterotypic cells.