Effect of Components on Apparent Shear Strength in Oil-Accommodating Adhesive

Two steel plates were bonded with oil-accommodating adhesives, the components of which are epoxy resin, NBR (nitrile rubber) modified epoxy resin, CaCO₃ and silica powder. The effect of components on the apparent shear strength was studied using the plates, which were covered with rust-preventing oil. The shear strength increased most effectively with the silica powder content, as compared with other components. Further, each component was exposed to the vapour of rust-preventing oil. Silica powder absorbed the largest amount of oil among the components per unit weight. We concluded that the performance of the oil-accommodating adhesive was attained by the strong oil absorption ability of silica powder in the adopted adhesive.     

Improvement of the mechanical properties of an ultrahigh molecular weight polyethylene fiber/epoxy composite by corona‐discharge treatment

The interfacial shear strength of an ultrahigh molecular weight (UHMW) polyethylene (PE) fiber/epoxy‐resin system was greatly improved by the corona‐discharge treatment of the fiber. The UHMW PE‐fiber/epoxy‐resin composite was prepared with corona‐discharge‐treated UHMW PE fiber. The mechanical properties of the composite sheet were determined by tensile testing. The tensile strength of the composite was also very much improved. However, the tensile strength of the composite was about one‐half of the theoretical strength. This result was due to the molecular degradation of the PE‐fiber surface caused by surface modification. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1162–1168, 2001     

Clinical usefulness of helical-scanning CT for the evaluation of arteriosclerotic carotid lesions

We examined arteriosclerotic carotid lesions in 76 patients using helical scanning CT (HES-CT), and evaluated the clinical usefulness of this method. A high speed slip-ring X-ray CT system was used. Scanning of the neck was performed for a 30 second period following intravenous bolus injection of non-ionic contrast medium, while couch top movement was 2.0 mm/sec. Multiplannar reconstruction images (MPR-image) and 3-dimensional surface images (3D-image) were reconstructed from the continuous raw data. MPR-images offered axial, coronal and sagittal images in which the lesion could be seen from any direction, and 3D-images that could be freely rotated were obtained by using a track ball and monitor. Eighteen cases were also evaluated by conventional angiography. Excellent HES-CT images were obtained in 73 cases, showing occlusion in 13, stenosis in 34, plaques without calcification in 15 and plaques with calcification in 74 vessels. A good correlation was obtained between HES-CT and angiogram in most cases, and in 6 cases, HES-CT was superior in the detection of stenosis, because it enabled us to observe the lesion from various directions. These results suggested that HES-CT was a minimally invasive, useful diagnostic method for the evaluation of arteriosclerotic carotid disease.     

A novel memory cell for multiport RAM on 0.5 μm CMOSSea-of-Gates

A novel memory cell circuit for multiport RAM on CMOS Sea-of-Gates (SOG) has been proposed. It contributes to the operation both at high speed and at low voltage. In addition, a fourfold read bit line technique is also proposed to reduce the access time. A multiport RAM generator with the novel memory cell has been developed. 2-port or 3-port RAM's with flexible bit-word configurations are available. Test chips containing seven generated RAM's were designed and fabricated on 0.5 μm CMOS SOG. The experimental results of the chip show that each RAM operates at over 1.4 V and that the address access time of the 3-port RAM (16b×256w) is 4.8 ns at 3.3 V     

Acrolein is a product of lipid peroxidation reaction. Formation of free acrolein and its conjugate with lysine residues in oxidized low density lipoproteins

Lipoprotein peroxidation, especially the modification of apolipoprotein B-100, has been implicated to play an important role in the pathogenesis of atherosclerosis. However, there have been few detailed insights into the chemical mechanism of derivatization of apolipoproteins during oxidation. In the present study, we provide evidence that the formation of the toxic pollutant acrolein (CH2=CH-CHO) and its conjugate with lysine residues is involved in the oxidative modification of human low density lipoprotein (LDL). Upon incubation with LDL, acrolein preferentially reacted with lysine residues. To determine the structure of acrolein-lysine adduct in protein, the reaction of acrolein with a lysine derivative was carried out. Employing Nalpha-acetyllysine, we detected a single product, which was identified to be a novel acrolein-lysine adduct, Nalpha-acetyl-Nepsilon-(3-formyl-3,4-dehydropiperidino )lysine. The acid hydrolysis of the adduct led to the derivative that was detectable with amino acid analysis. It was revealed that, upon in vitro incubation of LDL with acrolein, the lysine residues that had disappeared were partially recovered by Nepsilon-(3-formyl-3, 4-dehydropiperidino)lysine. In addition, we found that the same derivative was detected in the oxidatively modified LDL with Cu2+ and that the adduct formation was correlated with LDL peroxidation assessed by the consumption of alpha-tocopherol and cholesteryl ester and the concomitant formation of cholesteryl ester hydroperoxide. Enzyme-linked immunosorbent assay that measures free acrolein revealed that a considerable amount of acrolein was released from the Cu2+-oxidized LDL. Furthermore, metal-catalyzed oxidation of arachidonate was associated with the formation of acrolein, indicating that polyunsaturated fatty acids including arachidonate represent potential sources of acrolein generated during the peroxidation of LDL. These results indicate that acrolein is not just a pollutant but also a lipid peroxidation product that could be ubiquitously generated in biological systems.     

Morphology of New Fullerene Families with Negative Curvature

We consider the morphology of new fullerene families having negative Gaussian curvature formed by the introduction of 7- or 8-membered rings in a graphite sheet. The objects of our interest include the hypothetical structures of fullerene donuts and graphitic sponges. Their geometries are discussed based on the projection method on a honeycomb sheet which we have developed for normal fullerenes. Special emphasis is put on the new construction method for the structures of graphitic sponges. We demonstrate new carbon forms with three dimensionally periodic network based on polyhedral packing in space. The method can be applied to examine the local structures of amorphous carbon systems.     

The Durability of the Enantio-Differentiating Ability of a Tartaric Acid–NaBr-Modified Reduced Nickel Catalyst Pre-Modified in Tetrahydrofuran

The enantio-differentiating hydrogenation of methyl acetoacetate was carried out over a (R,R)-tartaric acid–NaBr-modified reduced Ni catalyst. The reduced Ni was pre-modified in a tetrahydrofuran solution of tartaric acid and NaBr at atmospheric pressure or at a high hydrogen pressure. The enantio-differentiating ability of 70–90% was maintained during 40 runs over the reduced nickel catalyst pre-modified at 9 MPa hydrogen and 373 K. The results indicated that the durability of a high enantio-differentiating ability of an in-situ-modified catalyst would be attributed to the modification conditions at the high hydrogen pressure of 9 MPa and the high temperature of 373 K in the autoclave.     

Ultrastructural evaluation following catheterization of the fallopian tube with a hysteroscopic catheter

PURPOSE: The purpose of this study was to determine the in vitro effects of a resin-modified glass-ionomer restorative material on human enamel. METHODS: Enamel specimens were restored with Photac-Fil, a resin-modified glass ionomer; Ketac-Fil, an autopolymerizing glass ionomer and silver amalgam. The samples were pH cycled and then subjected to an artificial caries challenge. Specimens were evaluated by fluoride microdrill biopsy and quantitative microradiography at 1, 2, and 3 mm from restorations. Data on fluoride content, lesion depth, and mineral content were analyzed by one-way ANOVA, Student's t test, Neuman-Keuls procedure (multiple [pairwise] comparison), and Pearson's product-moment correlation tests. RESULTS: There were significant differences in fluoride uptake, lesion depth, and mineral density between groups. Significant correlational relationships were also determined. CONCLUSION: This study demonstrates that Photac-Fil and Ketac-Fil prevent in-vitro demineralization of enamel and suggests different mechanisms of action for each material.     

The inhibition of the thermal oxidative degradation of polypropylene by various phenanthrols

All isomers of phenanthrol, 1-, 2-, 3-, 4-, and 9-phenanthrol, were prepared and the inhibitory effect of these compounds on the thermal oxidative degradation of isotactic polypropylene was examined by conventional oxygen uptake. The phenanthrols were found to be much more effective antioxidants than commercial 2,6-di-tert-butyl-4-methyl-phenol (abbreviated as BHT), and phenanthrene itself hardly showed any inhibitive effect. The effect of the phenanthrols was largely dependent on the position of the hydroxy group; the order of the effect was as follows: 1- > 4- > 2- > 3- > 9-phenanthrol > BHT. The phenanthrols were also good inhibitors of the radical polymerization of methyl methacrylate, and a fairly good correlation was observed between oxygen uptake and radical polymerization data.