Effect of ascorbic acid 2-0-alpha-glucoside on hydrocortisone-induced cataract formation in developing chick embryos: I. Comparison of the preventive effect of ascorbic acid derivatives

The effect of ascorbic acid 2-O-alpha-glucoside (AA-2G) on hydrocortisone (HC)-induced lens opacity in developing chick embryo was examined and compared with those of ascorbic acid (AsA) and ascorbic acid 2-phosphate (AA-2P). The opacity was dose-dependently inhibited by a single administration of 10 or 20 mumol/egg of AA-2G and by three repeated administrations of 1, 3 or 10 mumol/egg of AA-2G. AA-2G was the most effective among the three compounds. Glucose did not enhance the preventive effect of AsA against HC-induced opacity, and neither dehydro ascorbic acid nor glucose also prevented HC-induced cataract. In the histological study, we observed many small vacuoles in the nuclear region of the opaque lens treated with HC. AA-2G inhibited the formation of such vacuoles, an effect closely correlated with the prevention of cataract formation.     

Optimal and reference adaptive processes for the control of regional income disparities

This paper reports on studies into the controllability of the regional income disparities arising from multi-regional economic growth. The necessary condition is that no significant band of regional income disparities should result at the end of the planning period. The regional disparities among nine regions in Japan are explored using the interregional input-output technique and regional production functions. Furthermore, some potentially interesting research probes into the controllability of regional income disparities using the reference adaptive control technique are discussed.     

Dual role of dendritic cells in the induction and down-regulation of antigen-specific cutaneous inflammation

We have previously reported that contact sensitivity (CS) to dinitrofluorobenzene (DNFB) in C57BL/6 mice was mediated by MHC class I-restricted CD8+ T cells and down-regulated by MHC class II-restricted CD4+ T cells. In this study, we analyzed the contribution of dendritic cells (DC) in the induction of these two T cell subsets endowed with opposite functions. Hapten-pulsed skin- and bone marrow-derived DC, obtained from either normal C57BL/6 mice or from MHC class II (I+ II-) and MHC class I (I- II+)-deficient mice, were tested for their ability to prime normal mice for CS to dinitrofluorobenzene. Expression of MHC class I molecules by transferred DC was mandatory both for the induction of CS and for the generation of hapten-specific CD8+ T cells in lymphoid organs. I+ II- DC were as potent as I+ II+ DC in priming for CS, demonstrating that activation of effector CD8+ T cells can occur independently of CD4+ T cell help. I- II+ DC could not immunize for CS, although they could sensitize for a delayed-type hypersensitivity reaction to protein Ags. Moreover, I- II+ DC injected simultaneously with cutaneous sensitization down-regulated the inflammatory response, suggesting that hapten presentation by MHC class II molecules could prime regulatory CD4+ T cells. These results indicate that DC can present haptenated peptides by both MHC class I and class II molecules and activate Ag-specific CD8+ effector and CD4+ regulatory T cell subsets, concurrently and independently.     

Change in the molecular weight distribution of poly(ethylene oxide) caused by the complexation with poly(acrylic acid)

The complexation between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) was made by using double the molar quantity of either polymer component at pH 2 where the resulting complex completely precipitates. After the removal of the precipitate, PEO or PAA remaining in the supernatant was subjected to gel permeation chromatography to investigate the change in the molecular weight distribution (MWD) caused by the complexation. No remarkable difference is observed in the MWD curves for PEO[1] (M_w=1.37 × 10⁴) before and after the complexation with PAA[1] (M_w=1.10 × 10³) and PAA[2] (M_w=4.16 × 10⁵). However, the MWD curves of PEO[2] (M_w=1.26 × 10⁵) and PAA[2] become shortened and shift to the low molecular weight side after the complexation with PAA[1] or [2] and PEO[2], respectively. This tendency is enhanced by increasing the complexation temperature. From these results, it is indicated that the complexation between PEO and PAA deals with an equilibrium reaction, and the equilibrium constant is dependent on the chain length of both polymer components and also on the complexation temperature.     

The multiphase effect on crystal structure, hydrogen absorbing properties and electrode performance of Sc---Zr based Laves phase alloys

The crystal structure, hydrogen absorbing properties and electrode performance of Laves phase alloy systems, Sc---Zr---Ni---Mn and Sc---Ni---V systems, were studied by optical and scanning electron microscopy, X-ray powder diffraction, pressure-composition isotherm and electrochemical measurements. C14 and C15 Laves phases and minor ScNi-related phase were found in the Sc---Zr---Ni---Mn alloy system. The ScNi-related phase was composed of Sc, Zr and Ni elements. Two kinds of minor phase, BCC and ScNi-related phases, were identified in addition to the C15 phase in the Sc---Zr---Ni---V alloy system. The BCC contained mainly the element V. The ScNi-related phase contributed to an increase in the hydrogen capacity, but those in the V alloy system did not. The multiphase anode with a large amount of the ScNi-related phase showed a low durability against the KOH electrolyte. The substitution of Zr by Sc led to an improvement in the initial activation of the anode, but there was not a clear correlation between the presence of the multiphase in the anode and the rate capability.     

A novel cleaning method of gold-coated atomic force microscope tips for their chemical modification

For chemical modification of gold-coated AFM tips with thiol or sulfide compounds, a new two-step precleaning procedure was studied. The two-step cleaning procedure involves (i) oxidation of organic contaminants on the AFM tips with ozone treatment and (ii) reduction of the oxidized gold surface by immersing the oxidized tip into pure hot ethanol at ca. 65 degrees C. The chemically modified tips prepared from gold-coated AFM tips precleaned by the two-step procedure gave almost the same tip characteristics as those chemically modified immediately after gold vapor deposition in a factory. The present two-step cleaning procedure can be used widely for chemical modification of commercially available gold-coated AFM tips with thiol or disulfide compounds for chemical force microscopy.     

The effect of permanent dipole moments of adsorbates upon I-V characteristics of a bilayer tunneling junction between self-assembled monolayers on an Au(111) substrate and a gold tip

It is important to understand an electronic property of an interface between an organic material and a metal electrode. In the present work, we measured current-voltage (I-V) curves of self-assembled monolayers (SAMs) on Au(111) using a conducting atomic force microscope (AFM) with chemically modified Au-coated AFM tips. This contact resulted in a bilayer junction between the Au(111) substrate covered with one SAM and the Au-coated tip with the other SAM. An alkanethiol (octanethiol) and benzenemethanethiols with various terminal groups (-H, -CH(3), -Cl, -CF(3)) were used as the adsorbates. The shapes of the I-V curves depended on the terminal groups. This phenomenon was attributed to the change in the work function of gold due to different permanent dipole moments of the terminal groups.     

Hydrogen adsorption on graphene foam synthesized by combustion of sodium ethoxide

Hydrogen storage is a crucial technology for the realization of a carbon-neutral society. However, few materials have been able to approach useful hydrogen storage capacity at reasonable temperatures and pressures. Graphene has an extremely high surface-area-to-weight ratio, is strong, cheap, chemically inert, and environmentally benign. As such it may be an ideal substrate for hydrogen storage. Here we present synthesis of graphene foam by combustion of sodium ethoxide. This technique is low-cost, scalable, and results in a three-dimensional graphene network with a surface area of more than 1200 m²/g. It is applied as a hydrogen storage material at liquid nitrogen temperature, with a capacity of 2.1 wt%.     

Direct modulation of InGaAsP/InP double heterostructure lasers

Direct modulation of an InGaAsP/InP double heterostructure laser was investigated experimentally. Sinusoidal modulation up to 2.5 GHz was achieved with almost constant modulation efficiency. Pulse responses showed that the damped relaxation oscillation in light output was well suppressed.