Mössbauer characterization of calcium–ferrite oxides prepared by calcining Fe2O3 and CaO

Calcium ferrite oxides were prepared by calcining a mixture powder of iron- and calcium oxide. The ⁵⁷Fe-Mössbauer spectra of the calcium ferrites oxides were measured, revealing that the products should be Ca₂Fe₂O₅ and CaFe₂O₄, the ratio of which was dependent of the Fe/Ca atomic ratio of the mixture powder.     

Intramolecular Energy Transfer in Dithienogermole Derivatives

Dithienogermole (DTG) has been applied as a useful building unit of optical/semiconducting materials for organic optoelectronic devices because of its extended conjugation, high chemical stability, and good emissive properties. Although DTG has two substituents on the Ge atom, the substituents have been limited to simple alkyl and aryl groups in previous work. In this work, to further uncover the new functionalities of this useful building unit, various π-conjugated groups were introduced on Ge of DTG. It was expected that the introduction of π-conjugated groups would give rise to efficient energy transfer between the substituents and the DTG core, which are in proximity and linked by a Ge atom. The thus-prepared DTG compounds with fluorene, terthiophene, and pyrene units on Ge possessed well-separated frontier orbitals on the substituents and the DTG core, as proved by the absorption spectra and DFT calculations. The substituted DTG derivatives showed clear emission only from the energy acceptor even though the energy donor was photoexcited. This indicated the highly efficient energy transfer in these compounds. We also prepared more π-extended compound DTGFl2-Ph with phenyl groups on the DTG thiophene rings. DTGFl2-Ph showed strong emission in the visible region with efficient energy transfer properties. These results clearly indicate the potential application of the present DTG system as optical functional materials.     

Preparation and separation properties of oxalylurea‐bridged silica membranes

Two new bridged alkoxysilanes, bis(triethoxysilylalkyl)‐N,N′‐oxalylureas (alkyl = methyl or n‐propyl), bearing a highly rigid and polar oxalylurea unit in the bridges, were employed as precursors of bridged silica membranes. The gas and water separation performance of the membranes prepared from the precursors using the sol–gel process was investigated. Interestingly, the membrane properties depended on the alkyl chain length. The membrane containing methylene units (alkyl = methyl) was porous and rather hydrophilic but the other with longer propylene units (alkyl = n‐propyl) was non‐porous and more hydrophobic. High H₂/SF₆ gas permeance ratios of 3100 and 1700, and NaCl rejections of 89 and 85% for 2000 ppm aqueous NaCl were obtained using the membranes containing methyl and n‐propyl, respectively. The membrane with alkyl = methyl also showed a high CO₂/N₂ permeance ratio of 20.6 at 50°C. These results indicate the potential applications of the membranes as gas and water separation materials. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and specific solvatochromism of D–π–A type pyridinium dye

Donor–π–acceptor (D–π–A) type pyridinium dye bearing an iodide ion as the counter anion that has been newly synthesized showed specific solvatochromism, leading to large bathochromic shift of absorption band in halogenated solvents: the bathochromic shifts of the D–π–A type pyridinium dye in halogenated solvents are larger than those of the non-halogenated solvents of low ?_r values. Investigation of absorption spectral measurement, ¹H NMR measurements, and semi-empirical molecular calculations (AM1 and INDO/S using the SCRF Onsager Model) revealed that the intramolecular charge transfer (ICT) characteristics of the D–π–A type pyridinium dye became stronger in the halogenated solvents. On the basis of the experimental results and the theoretical calculations, the influences of halogenated solvent on the large bathochromic shift of D–π–A type pyridinium dye are discussed. ^©2012 Elsevier Science. All rights reserved.     

Palladium-catalysed dimerisation-distannylation of arynes: synthesis and reaction of 2,2'-distannylbiaryls

Two molar amounts of arynes were found to insert into a Sn-Sn bond of a distannane in the presence of a sub-stoichiometric amount of a palladium-phosphite complex, affording straightforwardly 2,2'-distannylbiaryls.     

Organic electroluminescent devices using organosilicon polymers containing phenylene or diethynylanthracene units

Double‐layer electroluminescent (EL) devices composed of an alternating polymer with mono‐, di‐, or tri‐silanylene and phenylene units, [(Si R) _m (C₆H₄)] _n (R = alkyl, m = 1–3) as a hole‐transporting layer, and tris(8‐quinolinolato)­aluminium(III) complex (Alq) as an electron‐transporting–emitting layer were fabricated. The longer silanylene chain lengths in the polymer, on going from m = 1 to m = 2 and 3, result in better electrical properties for the EL devices, implying that the σ–π conjugation in the polymers plays an important role in the hole‐transporting properties, including the hole‐injection efficiency from an anode. This is in marked contrast to the improved hole‐transporting properties that occur in response to reducing the silanylene chain length of silanylene‐diethynylanthracene polymers previously reported. The UV absorption maxima of silanylene‐phenylene polymers shift to longer wavelengths with increasing m, and their oxidation peak potentials in cyclic voltammograms shift to lower potential with increasing m, in accordance with the improved electrical properties of the device that are observed with the polymers containing the longer silanylene chain. A triple‐layer EL device with a hole‐transporting layer of monosilanylene‐diethynylanthracene polymer, an electron‐transporting–emitting layer of Alq, and an electron‐blocking layer of N,N′‐diphenyl‐N,N′‐bis(3‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine (TPD) exhibited a maximum efficiency of 1.0 lm W⁻¹ and a maximum luminance of 14750 cd m⁻², both of which are much higher than the values obtained from a conventional EL device with TPD/Alq. Copyright © 1999 John Wiley & Sons, Ltd.     

The pathophysiology of prospective memory failure after diffuse axonal injury - Lesion-symptom analysis using diffusion tensor imaging

Background  

Prospective memory (PM) is one of the most important cognitive domains in everyday life. The neuronal basis of PM has been examined by a large number of neuroimaging and neuropsychological studies, and it has been suggested that several cerebral domains contribute to PM. For these activation studies, a constellation of experimental PM trials was developed and adopted to healthy subjects. In the present study, we used a widely used clinical PM assessment battery to determine the lesions attributable to PM failure, with the hypothesis that lesion-symptom analysis using diffusion tensor imaging (DTI) in subjects with diffuse axonal injury (DAI) can reveal the neuronal basis of PM in everyday life.     

Rigid Crosslinked Polyacrylamide Monoliths with Well‐Defined Macropores Synthesized by Living Polymerization

Rigid crosslinked polyacrylamide monoliths with well‐defined macropores have been successfully fabricated by organotellurium‐mediated living radical polymerization (TERP) accompanied by spinodal decomposition. The TERP forms homogeneous networks derived from N,N‐methylenebis(acrylamide) (BIS), in which spinodal decomposition is induced to form macropores. Macropore diameter can be controlled from submicrons to a few microns, and also the obtained networks contain mesopores in the macroporous skeletons, which are collapsed by evaporative drying. They are promising materials with hydrophilic polyacrylamide surfaces and have enough strength to preserve the macropores from the surface tension arising in the repetitive swelling and drying that may occur in many applications.

     

Alignment-free classification of G-protein-coupled receptors using self-organizing maps

Proteins are classified mainly on the basis of alignments of amino acid sequences. Drug discovery processes based on pharmacologically important proteins such as G-protein-coupled receptors (GPCRs) may be facilitated if more information is extracted directly from the primary sequences. Here, we investigate an alignment-free approach to protein classification using self-organizing maps (SOMs), a kind of artificial neural network, which needs only primary sequences of proteins and determines their relative locations in a two-dimensional lattice of neurons through an adaptive process. We first showed that a set of 1397 aligned samples of Class A GPCRs can be classified by our SOM program into 15 conventional categories with 99.2% accuracy. Similarly, a nonaligned raw sequence data set of 4116 samples was categorized into 15 conventional families with 97.8% accuracy in a cross-validation test. Orphan GPCRs were also classified appropriately using the result of the SOM learning. A supposedly diverse family of olfactory receptors formed the most distinctive cluster in the map, whereas amine and peptide families exhibited diffuse distributions. A feature of this kind in the map can be interpreted to reflect hierarchical family composition. Interestingly, some orphan receptors that were categorized as olfactory were somatosensory chemoreceptors. These results suggest the applicability and potential of the SOM program to classification prediction and knowledge discovery from protein sequences.     

Dye-sensitized solar cells based on donor-π-acceptor fluorescent dyes with a pyridine ring as an electron-withdrawing-injecting anchoring group

A new‐type of donor–acceptor π‐conjugated (D‐π‐A) fluorescent dyes NI3 – NI8 with a pyridine ring as electron‐withdrawing‐injecting anchoring group have been developed and their photovoltaic performances in dye‐sensitized solar cells (DSSCs) are investigated. The short‐circuit photocurrent densities and solar energy‐to‐electricity conversion yields of DSSCs based on NI3 – NI8 are greater than those for the conventional D‐π‐A dye sensitizers NI1 and NI2 with a carboxyl group as the electron‐withdrawing anchoring group. The IR spectra of NI3 – NI8 adsorbed on TiO₂ indicate the formation of coordinate bonds between the pyridine ring of dyes NI3 – NI8 and the Lewis acid sites (exposed Tiⁿ⁺ cations) of the TiO₂ surface. This work demonstrates that the pyridine rings of D‐π‐A dye sensitizers that form a coordinate bond with the Lewis acid site of a TiO₂ surface are promising candidates as not only electron‐withdrawing anchoring group but also electron‐injecting group, rather than the carboxyl groups of the conventional D‐π‐A dye sensitizers that form an ester linkage with the Brønsted acid sites of the TiO₂ surface.