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- Author or Editor: T. Takahashi x
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The complexes of trivalent gallium, indium and thallium with trioctylamine (TOA, R3N) and trioctylmethylammonium chloride (TOMAC, R3R′NCl) were prepared by drying in vacuo the organic extracts from aqueous solutions containing the chlorides of their metals with TOA and TOMAC in benzene: R3NHGaCl4, (R3NH)2InCl5, R3NHTlCl4, R3R'NGaCl4, R3R'NInCl4 and R3RTlCl4. The prepared complexes were examined by TG and DTA under an atmosphere of nitrogen, and the products of their thermal decompositions, such as volatile matter and residues, were examined by gas chromatography, X-ay diffraction study and infrared spectrophotometry. It was found that the complexes of these trivalent metals with TOA and TOMAC decompose thermally to the chlorides (GaCl3, InCl3 and TlCl) through the cracking of alkyl groups.
In torsional braid analysis (TBA) the thermocouple junction is not in contact with the specimen, and therefore temperature standards are necessary. However TBA is devised only for application to high polymers, which are not appropriate for standards. The transition and fusion temperatures of several substances of low molecular weight, such as water,o-terphenyl, potassium nitrate andn-azoxyanisole, have been studied by TBA, and their applicability as standards to TBA is discussed. It is found that water,o-terphenyl and potassium nitrate can be used as standards.
Abstract
Seven representative wood species constituting caatinger forest were chosen to analyze Sc, V, Cr, Mn, Fe and Co, as well as Na, Mg and Al, by instrumental neutron activation analysis. In most cases of the soil, the concentration of the element tended to be higher with the increase of depth. Generally, the element partition from soil to root was higher in Mg and Co, whereas V showed higher partition rate from root to bark. The correlation within the elements was higher in the order of soil, root and bark.
In order to identify novel peptide signaling molecules involved in the regulation of developmental and physiological processes in the freshwater cnidarian, Hydra magnipapillata , we initiated a systematic peptide screening project, the Hydra Peptide Project. In the project, twelve neuropeptides were identified so far. The LWamide family is composed of seven members, which share a GLWamide motif at their C-termini. All the peptides have an ability to induce metamorphosis of Hydractinia serrata planula larvae into polyps. In Hydra , LWamides induce detachment of the bud from a parental polyp. A neuropeptide, Hym-355, enhances neuronal differentiation by inducing the multipotent interstitial stem cells to enter the neuron differentiation pathway. A myoactive neutopeptide, Hym-176, specifically and reversibly induces contraction of the ectodermal muscle of the body column, in particularly in the peduncle region of epithelial Hydra that totally lack nerve cells. Two members of a novel neuropeptide family (FRamides) were contained in the same precursor. However, they have opposite myoactive functions in epithelial hydra. From these results, it seems fair to say reasonable to conclude that the so-called ‘primitive’; nervous system of Hydra is in reality more complex than generally believed.
Abstract
Distribution of trace amount of Eu(III), or Am(III), in the aqueous/solid system containing humic acid and kaolinite, or montmorillonite, was studied by batch experiments. Humic acid was also adsorbed on the clay minerals and its adsorption isotherm can be regarded as a Langmuir type. It is shown that Eu(III), or Am(III), exists as humate complex either in the aqueous or on solid phase in the system including kaolinite, or montmorillonite. These results suggest that the organic-inorganic complex like clay minerals coated with humic substances is important as metal reservoir in the environment.
Abstract
Excess enthalpies (H E) of 17 binary mixtures of o- and m-isomers of dichlorobenzene, difluorobenzene, methoxymethylbenzene, dimethylbenzene, dimethoxybenzene, aminofluorobenzene, fluoronitrobenzene, diethylbenzene, chlorofluorobenzene, fluoroiodobenzene, bromofluorobenzene, chloromethylbenzene, fluoromethylbenzene, bromomethylbenzene, iodomethylbenzene, fluoromethoxybenzene, dibromobenzene at 298.15 K were measured. All excess enthalpies measured were very small, and those of o-+m-isomers of aminofluorobenzene, dibromobenzene and iodomethylbenzene were negative but 14 other binary mixtures of isomers were positive over the whole range of mole fractions. H E of o-+m-isomers of dimethoxybenzene showed the largest enthalpic instability and those of aminofluorobenzene showed the largest enthalpic stability. There was a correlation between dipole–dipole interaction, dipole–induced dipole interaction or entropies of vaporization and excess partial molar enthalpies at infinite dilution.
Summary Structural phase transitions upon the application of high pressure in LaGaO3 and LaCrO3, which were prospected from diffraction and thermal analyses of phase transition under ambient pressure, were discovered by using high-pressure X-ray diffraction. It was revealed that the crystal structures of LaCrO3 and LaGaO3 changed completely from that of orthorhombic distorted perovskite to that of a rhombohedral distorted one upon the application of pressure higher than 5.4 and 3.0 GPa, respectively, at room temperature. The variation of lattice constants with pressure was investigated for the high-pressure rhombohedral phases of LaCrO3 and LaGaO3 and isothermal compressibility was estimated. The variation of lattice constants with pressure at room temperature in the high-pressure rhombohedral phase was compared with that with temperature at ambient pressure in high-temperature rhombohedral phase. It was found that the application of pressure decreased the crystal symmetry, which was opposite to the result in the case of increasing the temperature.
Abstract
The coordination polymer Fe(3-chloropyridine)2Ni(CN)4 (2) has been prepared by a method similar to that for Fe(pyridine)2Ni(CN)4 (1). The complex (2) has been characterized by57Fe Mössbauer spectroscopy and a SQUID technique.57Fe Mössbauer and magnetic susceptibility data show that complex (2) exhibits spin-crossover behavior. The spin transition of (2) occurs between 120 and 80 K with very small hysteresis or without hysteresis. The temperature range of the spin transition in (2) is lower than that in (1). A residual high spin iron(II) fraction is observed at low temperatures in (2), being different from (1). SQUID data also show that samples treated differently yield different spin transition curves.
Abstract
Diffuse X-ray scattering from lead chalcogenides (PbS, PbSe, and PbTe) was measured at 15 and 294 K. The increase of the diffuse scattering intensities with the temperature was explained by the thermal correlation effects among thermal displacements of second nearest neighboring Pb–Pb atoms. The contribution from the second nearest neighboring atoms to the diffuse scattering was clearly confirmed.
Abstract
Three types of high-purity germanium (HPGe) detector systems for low-level radioactivity measurement were constructed in the laboratory near sea level. An anti-Compton system was set up by combining a large volume HPGe (rel. eff. 115%) with a well type NaI(Tl). The detection limit (D.L.) of 137Cs of an ashed oyster sample for the anti-Compton mode of 115% Ge was 0.023 Bq/sample for 8·104 s counting, whereas 0.035 Bq/sample for the normal mode. Under similar measuring conditions, D.L. of 137Cs for a medium volume HPGe (rel. eff. 51%) was 0.042 Bq/sample. A low-background Ge-LEPS (Low Energy Photon Spectrometer) was sufficiently sensitive for low level measurements of 210Pb, 234Th and other low energy gamma-emitters. The detection limit for 210Pb in the sample shape of 60 mm diameter by 2 mm thick was about 0.05 Bq/sample for 5.0·105 s background counting. Using this LEPS, it was found that 210Pb behaves similarly to 7Be in both air and precipitation (snowfall).
