Fabrication of a poly-Si thin-film transistor with storage capacitor

The fabrication process of a low-temperature poly-Si thin-film transistor (TFT) with a storage capacitor was studied. The atmospheric-pressure chemical-vapour deposited SiO₂ protected the buried indium tin oxide (ITO) from reduction by a pure H₂ plasma treatment that was essential for the effective improvement of the poly-Si TFT characteristics. Thus, a storage capacitor with an ITO (picture electrode)-SiO₂-ITO (buried common electrode) structure was successfully fabricated. The poly-Si TFT with a channel width/length W/L ratio of 5 drove a 3 pF storage capacitor in 2 μs, and it showed superior driverability for LCD use. The TFT also had good hold characteristics under illumination for the realization of grey-scale representation.     

Effect of hydrogen charging on dislocation behavior in Ni-Cr and Ni<Subscript>2</Subscript>Cr alloys

The effects of hydrogen charging on the dislocation behaviour in Ni-Cr binary alloys have been investigated by means of transmission electron microscope (TEM) observations using single-crystalline specimens. The deformation mode of Ni-Cr alloys in the absence of hydrogen is characterized by planar dislocations. However, hydrogen charging changed the dislocation configurations to promote curved dislocations, such as dislocation loops and dipoles. The hydrogen-affected dislocation configurations are enhanced with increasing Ni content and reducing Cr content. Weak-beam images show that the Shockley partials of the hydrogen-affected dislocations frequently constrict to make kinks and cross-slip, as if the dislocations were generated by a thermally activated process. The effect of hydrogen charging on superdislocations of a Ni₂Cr superstructure has been also investigated using an aged 70Ni-30Cr alloy. While the deformation mode in the Ni₂Cr superlattice is classified as five variants of superdislocation triplets and one variant of ordinary dislocations, the hydrogen charging has preferred the ordinary dislocations to the superdislocation triplets. The results suggest that the charged hydrogen changes the local plasticity to affect the deformation dynamics in Ni-Cr alloys, where the influence of hydrogen on the plasticity is sensitive to the Ni/Cr concentration and the symmetry of atomic arrangement.     

Protein C Osaka 10 with aberrant propeptide processing: loss of anticoagulant activity due to an amino acid substitution in the protein C precursor

We studied the molecular basis of protein C deficiency in a family with a history of thromboembolic disease. An approximately 50% reduction in anticoagulant activity despite normal levels of protein C amidolytic activity and antigen was detected in plasma from the proband. All the exons and intron/exon junctions of the protein C gene were studied using a strategy that combined polymerase chain reaction amplification with DNA sequencing of the amplified fragments. We identified a C-to-A change at nucleotide number 1387 of the protein C gene in the proband and his mother, and this mutant was designated protein C Osaka 10. The C-to-A change resulted in the substitution of Ser for Arg at position -1, which is the processing protease cleavage site. The mutant protein C was partially purified from plasma of the patient's mother using barium adsorption followed by ion-exchange column chromatography. It eluted at the same sodium chloride concentration as normal protein C, and thus gamma-carboxylation of the mutant protein appeared to be normal. The apparent molecular weight of this mutant protein C was the same as that of the normal protein on immunoblotting. Amino-terminal sequence analysis showed that the light chain of the mutant protein C had an additional Ser at position-1. Thus, the loss of anticoagulant activity of protein C Osaka 10 can be explained by alteration of the conformation of the Gla domain by the additional Ser in the mutant molecule.     

Crystal orientation of β-phase isotactic polypropylene induced by magnetic orientation of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide

Melt crystallization of isotactic polypropylene (iPP), containing crystallites of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide (DCNDCA) as a nucleating agent of the the β-phase iPP crystal, is carried out under a magnetic field (6 T) to obtain the alignment of the iPP crystal induced by magnetic alignment of DCNDCA. In a previous paper, DCNDCA was reported to undergo magnetic alignment in a liquid suspension. The obtained iPP sample exhibits alignment of the β-phase crystal with the c-axis aligned perpendicular to the magnetic field. The comparison of this alignment of iPP with the reported magnetic alignment of DCNDCA indicates that the β-phase crystal grows epitaxially on the DCNDCA crystal. The (330)_β plane of the iPP crystal lies on the bc-plane of the DCNDCA crystal in which the direction of the c-axis of the iPP coincides with the direction of the b-axis of the DCNDCA crystal.     

Protein modification by a Maillard reaction intermediate methylglyoxal. Immunochemical detection of fluorescent 5-methylimidazolone derivatives in vivo

Methylglyoxal (MG), an endogenous metabolite that increases in diabetes, is a common intermediate in nonenzymatic glycation (Maillard reaction) in vivo. Here we describe the immunochemical approach to the detection of MG adducts in proteins in vitro and in atherosclerotic lesions of human aorta in vivo. The reaction of protein (bovine serum albumin) with MG led to selective loss of arginine and lysine residues, accompanied by the formation of 5-methylimidazolone (N delta-(5-methylimidazolon-2-yl)ornithine) and imidazolysine (1,3-di-lysino-4-methylimidazole) derivatives, respectively. The anti-5-methylimidazolone antibody was prepared by immunizing rabbits with a MG-keyhole limpet hemocyanin conjugate and purifying the serum on an affinity gel prepared by covalent attachment of the 5-methylimidazolone derivative. The antibody cross-reacted with the proteins treated with not only MG but trioses, such as hydroxyacetone, dihydroxyacetone, and glyceraldehyde. The immunohistochemical analysis revealed that atherosclerotic lesions of human aorta contained 5-methylimidazolone derivatives whose distributions were identical to those of advanced glycation end products (AGEs) detected by the anti-AGE antibody.     

In-plane transport properties of Si/Si1-xGexstructure and its FET performance by computer simulation

Transport properties of ungated Si/Si_1-xGe_x are studied by an ensemble Monte Carlo technique. The device performance is studied with a quantum hydrodynamic equation method using the Monte Carlo results. The phonon-scattering limited mobility is enhanced over bulk Si, and is found to reach 23000 cm²/Vs at 77 K and 4000 cm²/Vs at 300 K. The saturation velocity is increased slightly compared with the bulk value at both temperatures. A significant velocity overshoot, several times larger than the saturation velocity, is also found. In a typical modulation-doped field-effect-transistor, the calculated transconductance for a 0.18 μm gate device is found to be 300 mS/mm at 300 K. Velocity overshoot in the strained Si channel is observed, and is an important contribution to the transconductance. The inclusion of the quantum correction increases the total current by as much as 15%     

Permeation and separation of organic liquid mixtures through liquid-crystalline polymer networks

A side-chain liquid-crystalline polymer (LCP) was synthesized by the addition of the mesogenic monomer to poly(methyl siloxane) in presence of a Pt-catalyst. When an aqueous solution of 10wt% ethanol was permeated through a LCP membrane by pervaporation at various temperatures, the permeation rate increased with increasing temperature and drastically changed at glass-nematic (Tg) and nematic-isotropic (TNI) transition temperatures of the LCP membrane. The LCP membrane exhibited the waterpermselectivity in the glassy and liquid-crystalline states. The ethanol concentration in the permeate increased with increasing permeation temperature and the LCP membrane changed from the waterpermselectivity to the ethanol-permselectivity around TNI. These results suggested that the permselectivity was influenced by the change of the LCP membrane structure, that is, its state transformation. It was found that a balance of the orientation of mesogenic groups and flexibility of siloxane chains is very important for the permeability and selectivity.     

Characteristics of IgA anti-HIV antibodies in plasma from patients with HIV infection

The concentration of total IgA and the specificity and molecular size of IgA anti-human immunodeficiency virus (HIV) type-1 antibodies in plasma obtained from individuals at different stages of HIV infection were analyzed. The concentration of total IgA in the plasma was not decreased even in the late stage of HIV infection, in contrast with those of total IgG and IgM. The IgA anti-HIV antibodies differed to the IgG anti-HIV antibodies in their specificity as determined by Western blotting. The IgA antibodies mainly bind to Env glycoproteins. The IgA anti-HIV antibodies in plasma were detected between IgG and IgM by gel filtration, suggesting the presence of polymeric IgA anti-HIV antibodies. These results indicate that the production of non-specific IgA in plasma is enhanced by unknown mechanisms in every stages of HIV infection, and suggest that IgA anti-HIV antibodies in plasma which are possibly polymeric and have unique specificity may play an important role in HIV infection.     

Biodegradation of glutaraldehyde-tanned human umbilical vein grafts

A retrospective analysis of the long-term behavior of 111 glutaraldehyde-tanned human umbilical vein (HUV) grafts implanted between September 1977 and December 1993 was conducted. A total of 81 patients, with a mean age of 68.7 years, received the grafts and were followed up for between 1 and 131 months. The 5-year primary cumulative patency rate for above-knee femoropopliteal bypass was 83.1%, whereas that of other bypasses was 60.9%. An aneurysm of the graft was defined as a physically apparent localized dilatation, with diffuse ectasia being excluded. There were 11 aneurysms found in 9 grafts, 2 of which arose at the factory-made suture lines. The accumulated incidence of aneurysms had reached 21.9% by the 6th year. One aneurysm compressed the graft and resulted in limb-threatening ischemia and another resulted in frank rupture. Moreover, reinforcement of the mesh could not prevent aneurysm development, the repair of which is mandatory due to the risk of rupture and acute thrombosis. The HUV grafts showed an acceptable patency rate in the above-knee location, but the incidence of aneurysm formation after 5 years was abnormally high. Thus, both the risks and benefits of HUV grafts must be taken into account when considering their clinical application.