Linkage of antisocial alcoholism to the serotonin 5-HT1B receptor gene in 2 populations

We examined the effects of repeated administration of (S)-alpha-fluoromethylhistidine (FMH), a specific inhibitor of histidine decarboxylase (HDC), on radial maze performance and brain contents of histamine and amino acids in rats. By daily subcutaneous (s.c.) administration of FMH (100 mg/kg), rats showed significant enhancement of a radial maze performance without changes in locomotion. Six days after FMH treatment, the histamine levels both in the cerebral cortex and diencephalon decreased significantly. However, the glutamate and glycine levels significantly increased in the cerebral cortex and hippocampus. These results suggest that FMH enhances the acquisition phase of radial maze study with the increases in glutamate and glycine levels in the cerebral cortex and hippocampus of rats.     

Inhibitory effect of forskolin on myosin phosphorylation-dependent and independent contractions in bovine tracheal smooth muscle

In bovine tracheal smooth muscle, carbachol (CCh, 1 microM) and high K+ (72.7 mM) induced sustained increases in cytosolic Ca2+ level ([Ca2+]i), myosin light chain (MLC) phosphorylation and force of contraction. Forskolin (FK, 1-10 microM) inhibited the CCh-induced increase in [Ca2+]i, MLC phosphorylation and force in parallel. In contrast, FK inhibited the high K(+)-induced contraction and MLC phosphorylation without changing [Ca2+]i. In the absence of extracellular Ca2+ (with 0.5 mM EGTA), CCh (10 microM) and caffeine (20 mM) induced transient increase in [Ca2+]i and contractile force by releasing Ca2+ from cellular store. FK strongly inhibited the CCh-induced Ca2+ transient, but failed to inhibit the caffeine-induced Ca2+ transient. In the absence of external Ca2+, 12-deoxyphorbol 13-isobutylate (DPB, 1 microM) induced sustained contraction without increase in [Ca2+]i and MLC phosphorylation. FK inhibited this contraction without changing [Ca2+]i. In permeabilized muscle, Ca2+ induced contraction in a concentration-dependent manner. FK (10 microM) and cAMP (1-100 microM) shifted the Ca(2+)-force curve to the higher Ca2+ levels. CCh with GTP, GTP gamma S or DPB enhanced contraction in the presence of constant level of Ca2+. Forskolin and cAMP also inhibited the enhanced contractions in the permeabilized muscle. In the permeabilized, thiophosphorylated muscle, ATP induced contraction in the absence of Ca2+. cAMP (300 microM) had no effect on this contraction. These results suggest that forskolin inhibits agonist-induced contraction in tracheal smooth muscle by multiple mechanisms of action; 1) inhibition of MLC phosphorylation by reducing Ca2+ influx and Ca2+ release, 2) inhibition of MLC phosphorylation by changing the MLC kinase/phosphatase balance, and 3) inhibition of regulatory mechanism which is not dependent on MLC phosphorylation.     

Effects of x-ray tube-voltage ripple and current mode on patient dose

This paper proposes a radiographic sensitivity attenuation curve for screen-films systems. This curve expresses the relative inverse value of mAs value needed to give the same photographic density. This curve decreases more slowly with increasing object thickness than the exposure attenuation curve generally used hitherto. By using the radiographic sensitivity attenuation curve and the exposure attenuation curve, the voltage-ripple dependence of mAs values and patient dose for the same photographic density was obtained. As predicted theoretically in a previous paper [Med. Phys. 18, 921 (1991)], it was verified quantitatively the reverse order that larger ripple values resulted in lower patient dose and lower mAs value for the unsaturating current mode at large ripple. This reverse order clearly appeared in two-pulse units. These phenomena were experimentally verified. As a result it was found that in radiographing with a two-pulse unit, larger mA value results in lower patient dose.     

Electrical properties of HgCdTe epilayers doped with silver using an AgNO3 solution

We employed AgNO₃ solutions for doping Ag in liquid phase epitaxy (LPE) grown Hg_0.78Cd_0.22Te epilayers and found that the minority carrier lifetimes became longer so that the diode properties improved. After annealing LPE grown Hg(1-x)Cd(x)Te layers (x=0.22) in Hg atmosphere, the epilayers were immersed in an AgNO₃ solution at room temperature. The typical carrier concentrations of holes was 3 × 10¹⁶ cm⁻³ at 77K. These values were almost the same as for the nondoped wafers. Also, its acceptor level was 3 to 4 meV. This shows that the Ag was activated. The doped crystals have lifetimes several times longer than those of the nondoped crystals. Numerical fitting showed the lifetime was limited mostly by the Auger 7 process. The Shockley-Read-Hall recombination process was not effective. To examine the Ag-doped wafer, we fabricated photodiodes using standard planar technology. The diodes have an average zero-bias resistance of several MΩ and a shunt resistance of about 1 GΩ for a 10 μm cutoff wavelength at 78K. These values are about four times higher than those of nondoped diodes. The photo current is also two times higher at the same pixel size. This shows that the quantum efficiency is increased. The extension of the lifetime contributes to the high resistance and the high quantum efficiency of the photodiode.     

Growth of silicon nanowires on H-terminated Si {111} surface templates studied by transmission electron microscopy

We have studied the growth of silicon nanowires (SiNWs) by means of transmission electron microscopy. SiNWs are grown from nanocatalysts via the Vapor-Liquid-Solid (VLS) mechanism using silane (SiH4) gas as a source gas. The nanocatalysts are prepared on a hydrogen (H)-terminated Si surface. We have examined the formation mechanism of nanocatalysts on H-terminated surface and have observed several structural variants of SiNWs. According to the study we have suggested that many structural variations of SiNWs are possible, which modify the structural properties of SiNWs to great extents.     

Part III: Surface-enhanced Raman scattering of amino acids and their homodipeptide monolayers deposited onto colloidal gold surface

Surface-enhanced Raman scattering (SERS) spectra were measured for monolayers of various amino acids: L-methionine (Met), L-cysteine (Cys), L-glycine (Gly), L-leucine (Leu), L-phenylalanine (Phe), and L-proline (Pro) and their homodipeptides (Met-Met, Cys-Cys, Gly-Gly, Leu-Leu, Phe-Phe, and Pro-Pro) deposited onto a colloidal gold surface. Orientation of amino acids and their homodipeptides, as well as specific-competitive interactions of their functional groups with the gold surface, were predicted by detailed spectral analysis of the obtained SERS spectra. The analysis performed allowed us to propose a particular surface geometry for each amino acid and homodipeptide on the gold surface. In addition, we compared the structures of these molecules adsorbed on colloidal gold and silver surfaces.     

Cost analyses of uranium enrichment by laser isotope separation process

The probability of the selective two-step photoionisation of ²³⁵U atoms by laser and ultraviolet radiations is estimated from the rate equations for uranium atoms with two isotopes with three levels. The population of ²³⁵U ions is obtained by linearising the rate equations. We have calculated the ion production rates for three cases in which the laser and ultraviolet powers are changed while the atom density is kept constant. The power consumption and the capital investment required for the large-scale laser enrichment plant conceptionally designed based upon the above results, and consequently the unit cost of separative work, are estimated. It is concluded that the laser isotope separation process could be competitive with the conventional gaseous diffusion and gas centrifugal methods.     

Advanced quantum dot and photonic crystal technologies for integrated nanophotonic circuits

Two types of nanophotonic technologies—two-dimensional photonic crystal (2D PC) slab waveguides (WGs) and quantum dots (QDs)—were developed for key photonic device structures in the future. For an ultrafast digital photonic network, an ultrasmall and ultrafast symmetrical Mach–Zehnder (SMZ)-type all-optical switch (PC-SMZ) and an optical flip–flop device (PC-FF) have been developed. To realize these devices, one method is to develop a selective-area molecular beam epitaxial growth QD technique by employing a metal mask method. Another method is to establish a new design method, i.e., topology optimization of the 2DPC WG with a wide and flat bandwidth, high transmittance, and low reflectivity. We also fabricated an optical microcavity in a photonic crystal slab embedded with GaAs QDs by droplet epitaxy. The Purcell effect on the exciton emission of GaAs QDs was confirmed by microphotoluminescence and lifetime measurements.     

Determination of substances in polylactic acid products for food-contact use and mutagenicity of their migration solutions

Specification tests defined in the Japanese Food Sanitation Law were conducted on 7 polylactic acid food-contact products. Moreover, the content and migration of other compounds were examined by means of ICP-AES, GC/MS and mutagenicity tests. All products met their specifications, and migration levels of heavy metals were negligible. No notable peak was observed in GC/MS analysis. Moreover, all products gave negative results in both rec-assay and the umu-test. An increase in the β-galactosidase activity in the umu-test observed with the migration solution of soup bowl was due not to polylactic acid, but to the polyurethane coating.