Study on triazine thiols. IV. Action of triazine thiols and their metal salts to peroxide

Decomposition of t-butylhydroperoxide was retarded by triazine thiols and their zinc salts, but accelerated by the copper salts of triazine thiols as well as sulfur compounds such as dithiocarbamates and mercaptobenzothiazolates. Triazine thiols and their zine salts are effective antioxidants for polyethylene crosslinked with peroxide and containing copper, and for protecting epichlorohydrin vulcanizates against attack by “sour” or hydroperoxide-containing gasoline.     

Concentration of acetic acid in sulfite pulp evaporation drain by reverse osmosis

The evaporation drain of sulfite pulp spent liquor contains few volatile fatty acids, most of which is acetic acid. The main objective of this study is to recover acetic acid as the concentrated solution (about 4%), which could be used as a culture medium of the yeast. As acetic acid can easily pass through the cellulose acetate membrane, SP drains neutralized by NaOH, NH₄OH and Ca(OH)₂ were used as the feed solutions. In all cases, concentration by reverse osmosis was successfully carried out provided the appropriate pretreatment was employed. The recovery of acetic acid was 95.6, 90.5 and 98.2% for Na-, NH₄-, and Ca-drain, respectively. In addition, the recovered (permeated) water may be used as an industrial one.     

Functional expression of three isoforms of human nitric oxide synthase in baculovirus-infected insect cells

Complementary DNAs encoding three human isoforms (neuronal, inducible, and endothelial) of nitric oxide synthase were cloned into the baculovirus expression vector pVL1392/1393. Transfection of Sf-9 insect cells with the recombinant baculovirus resulted in the expression of high levels of nitric oxide synthases. The expressed proteins of neuronal and inducible nitric oxide synthase were predominantly soluble, whereas the endothelial enzyme was for the most part, particulate. Recombinant enzymes were purified with 2',5'-ADP Sepharose affinity chromatography. The effects of reference enzymatic inhibitors (NG-methyl-L-arginine, NG-nitro-L-arginine and N-iminoethyl-L-ornithine) on recombinant expressed proteins were not significantly different from native nitric oxide synthase enzyme preparations. L-aminoguanidine was found to be much less potent in inhibiting recombinant or native human inducible nitric oxide synthase compared to the murine isoform. These findings indicate previously unappreciated interspecies differences in the action of nitric oxide synthase enzymatic inhibitors. The functional expression of human nitric oxide synthase isoforms in a heterologous expression system allowed screening of novel inhibitors. Studies indicated that S-ethylisothiourea and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine were potent novel inhibitors of human nitric oxide synthases.     

Use of liposome encapsulated hemoglobin as an oxygen carrier for fetal and adult rat liver cell culture

Engineering liver tissue constructs with sufficient cell mass for transplantation implies culturing large numbers of hepatocytes in a reduced volume; however, providing sufficient oxygen to dense cell cultures is still not feasible using only conventional culture medium. Liposome-encapsulated hemoglobin (LEH), an oxygen-carrying blood substitute originally designed for short-term perfusion, may be a good candidate as an oxygen carrier to cultured liver cells. In this study, we investigated the feasibility of maintaining long term hepatocyte cultures using LEH. Primary fetal and adult rat liver cells were directly exposed to LEH for 6 to 14 days in static culture or in a perfused flat plate bioreactor. The functions and viability of adult rat hepatocytes exposed to LEH were not adversely affected in static monolayer culture and were even improved in the bioreactor. However, some cytotoxicity of LEH was observed with fetal rat liver cells after 4 days of culture. LEH, though a suitable oxygen carrier for long-term culture of mature hepatocytes, is not suitable in its present form for perfusing fetal hepatocyte cultures in direct contact with the liposomes; either the LEH will have to be made less toxic or a more sophisticated bioreactor that prevents the direct contact between hepatocytes and perfusates will have to be designed if fetal cells are to be used for liver tissue engineering.     

A 128-kb FeRAM macro for contact/contactless smart-card microcontrollers

This paper describes a 128-kb FeRAM macro for smart-card microcontrollers. This macro, which was designed and fabricated using a 0.35-/spl mu/m three-metal CMOS and a Capacitor-on-Metal/Via-stacked-Plug (CMVP) process technology, is ideally suited for recent system LSIs such as smart-card microcontrollers. It has a flexible memory size ranging from 32 to 128 kb, a low consumption current of 0.3 mA, and endurance of more than 10/sup 8/ write/read cycles under a wide range of supply voltages, from 2.7 to 5.5 V. These characteristics, which are required of not only contact-type smart-card microcontrollers but also contactless-type ones, were achieved by using four newly developed circuit technologies: 1) a three-metal CMVP memory cell; 2) a voltage-regulating architecture; 3) a main/sub bitline and wordline structure; and 4) a dynamic-type offset sense amplifier.     

Stability,cure properties,and applicability as one part adhesives of systems of divalent metal salts of mono(hydroxyethyl) phthalate–anhydride–bisepoxide

Heterogeneous curable compositions of divalent metal salts of mono(hydroxyethyl) phthalate–anhydride–bisphenol A diglycidyl ether (BADG) systems were prepared by merely mixing these components at room temperature. Stability at room temperature and cure properties at high temperature of the compositions were investigated for evaluating their applicability as one part adhesive. It was found that the systems containing Mg were generally more stable than those containing Ca. Similarly, at 150°C the Ca-containing systems showed generally shorter gelation time than the Mg-containing ones, due to the fact that the Ca salt dissolves more rapidly and enters into the addition reaction with the anhydride, leading to the faster appearance of the catalytic activities of the Ca carboxylate group. Among the various combinations of components, the metal salt–succinic anhydride (SA)–BADG systems were stable at room temperature for more than 6 months and rapidly cured at high temperature, showing excellent adhesive properties. This result indicates that the SA-containing systems should be of interest in applications to one part adhesives.     

The interaction between co-polymer of vinylpyrrolidone and vinylacetate and anionic surfactants in aqueous solutions

The interaction of co-polymers of vinylpyrrolidone-vinylacetate with anionic surfactants, such as lithium dodecyl sulfate (LiDS), lithium perfluorooctane sulfonate (LiFOS) in aqueous solution, has been studied. When the content of vinylacetate in the co-polymers increases, reduction in the surface tension of co-polymers alone becomes significant. In mixtures of co-polymers and surfactants, co-polymer-LiFOS complexes are formed at lower surfactant concentration than that of co-polymer-LiDS. The micropolarity of the co-polymers-surfactant complexes depends on the composition of co-polymers and is higher for co-polymer-LiFOS than that for co-polymer-LiDS. Further, the solubilization behavior of α-(o-tolylazo-)-β-naphthylamine (Yellow OB) (Tokyo Kasei Co., Ltd., Tokyo, Japan) in the co-polymer-surfactant complexes is almost independent of the co-polymer composition, but different from the surfactants, where a very low solubilized amount of Yellow OB is observed for co-polymer-LiFOS.     

Crosslinking of PVC and NBR blends

The purpose of our work is to control the interfacial bonds between PVC and NBR using the ammonium salts of triazine thiols and dithiodimorpholine (DTDM) and thereby reveal the relation between the interfacial bonds and the final mechanical properties of products. In the experimental work a two-stage process was used. At first, an NBR/PVC blend was mixed with a mono-tetra-n-butylammonium salt of triazine trithiol at a temperature of 100°C on a two-roll mill to give the branching structure of triazine thiols into PVC. In the second stage branched NBR/PVC reacted with DTDM to afford the branched PVC containing trithiomorphonyl groups. In the presence of ZnO at 160°C trithiomorphonyl groups react with NBR to form a crosslinking structure between NBR and PVC. The mechanical properties of cured NBR/PVC blends were markedly improved by the treatment process and after addition of tetramethylthiuram monosulphide also. The mechanical properties were not improved by increasing the concentration of TT-TBA (tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol) over 4.2 phr.     

Research and development related to PFM for aged nuclear components

At the Japan Atomic Energy Research Institute (JAERI), research activities related to probabilistic fracture mechanics (PFM) have been conducted as a part of the research program on aging and structural integrity of LWR components. This paper describes the outline of two activities related to PFM, i.e. the development of a PFM code and a contract research on ‘Application of PFM Methodology to Reliability Assessment of Nuclear Components’ implemented by the Japan Welding Engineering Society (JWES). In the former research, a new PFM code PASCAL (PFM Analysis of Structural Components in Aging LWR) was developed. This code has some new functions in models of semi-elliptical crack extension, elastic–plastic fracture analysis based on R6 method and options for the evaluation of overlay cladding and warm pre-stress (WPS) effect. Besides, the code has the function to evaluate the effect of irradiation embrittlement recovery by thermal annealing of a reactor pressure vessel and re-irradiation embrittlement. Based on the analyses on benchmark problem conducted by USNRC/EPRI, performance and functions introduced in the code were examined. Some case studies were also carried out to investigate the influence of various parameters. On the other hand, JAERI has been sponsoring the PFM related activities in relation to the structural integrity of LWR components. These activities have been conducted at JSME and JWES. The objective of this activity has been to provide for the future need of PFM methodology.     

Conserved gene structure and genomic linkage for D-dopachrome tautomerase (DDT) and MIF

Macrophage migration inhibitory factor (MIF) and D-dopachrome tautomerase (DDT) are small proteins, which are related both by sequence and by in vitro enzyme activity. Here we show that the gene for DDT in human and mouse is identical in exon structure to MIF. Both genes have two introns that are located at equivalent positions, relative to a twofold repeat in protein structure. Although in similar positions, the introns are in different phases relative to the open reading frame. Other members of this superfamily exist in nematodes and a plant, and a related gene in C. elegans shares an intron position with MIF and DDT. In addition to similarities in structure, the genes for DDT and MIF are closely linked on human Chromosome (Chr) 22 and mouse Chr 10.