A new recycling system for expanded polystyrene using a natural solvent. Part 1. A new recycling technique

A new recycling technique has been developed which uses a natural solvent, d limonene, to shrink expanded polystyrene (EPS). d-Limonene is a natural vegetable oil which is extracted from the rinds of citrus fruits and is a good solvent of EPS. Limonene has almost the same solubility as toluene at room temperature. This technique reduces the volume of EPS to about 1/20th of the original. Contracted EPS is recyclable with almost no molecular weight degradation because d-limonene acts as an antioxidant of polystyrene during the heating process. © 1998 John Wiley & Sons, Ltd.     

Modeling the effect of oxygen on vapor phase diamond deposition inside micro-trenches

For the same feed gas composition, radical species concentrations vary with depth inside micro-trenches during diamond deposition. However, the feed gas compositions are typically used for predicting diamond deposition vs. non-diamond deposition. So, any type of modeling for predicting diamond deposition quality and uniformity inside trenches and onto three-dimensional objects is not possible. In this regard, a simple modeling approach utilizing a recently constructed C–H–O ternary diagram, based on radical species composition by Eaton and Sunkara [Eaton and Sunkara, Diam. Relat. Mater., 9 (2000) 1320], demonstrated the diamond deposition process inside trenches. Specifically, the effect of oxygen in the feed gases on the depths at which diamond can be deposited is modeled under both Knudsen and Fickian diffusion conditions and compared with experimental observations. The results suggested that certain feed gas phase compositions (C/O ratio) help increase the aspect ratio (>2.0) at which diamond deposition can be achieved.     

Properties of biomedical pressure-sensitive adhesive copolymer films with pendant monosaccharides

Glucosyloxyethyl methacrylate (GEMA) was copolymerized with butyl acrylate (BA) for the preparation of a biomedical pressure-sensitive adhesive with pendant monosaccharides, for possible use in medical applications. The measurements of 180° peel strength, ball tack, and holding power for the GEMA–BA copolymer films revealed that the film at the GEMA content of 5 mol % has excellent pressure-sensitive adhesive properties. Protein adsorption onto the GEMA–BA copolymer film hardly occurred due to very low interfacial free energy between its surface and water. Release profiles of vitamin B₁₂ from the GEMA–BA copolymer film suggests that it is useful as a material for a transdermal therapeutic system. © 1995 John Wiley & Sons, Inc.     

Endothelin subtype A receptor antagonist induces osteopenia in growing rats

Previous studies suggested that endothelin (ET) peptides are involved in bone metabolism. We examined the effects of long-term blockade of the ET(A) receptor, a receptor subtype primarily involved in the anabolic actions of ET, on bone mineral status in growing rats. Eight-week-old rats injected intraperitoneally with FR139317 50 mg/kg body weight, a specific ET(A) receptor antagonist, for 2 or 4 weeks were compared with control rats injected with vehicle only. Treatment with FR139317 caused a significant decrease in bone mass in the lumbar spine as determined by dual-energy x-ray absorptiometry (DXA). FR139317-induced osteopenia was associated with a significant decrease in the serum osteocalcin concentration but no change in the urinary excretion of pyridinium cross-links of collagen. Our findings indicate that long-term blockade of the ET(A) receptor reduces bone formation and induces osteopenia in growing rats. Our results suggest that ET produced by vascular endothelial cells plays an important role in bone growth and metabolism in vivo.     

Involvement of CD4+ T cells in the development of dextran sulfate sodium-induced experimental colitis and suppressive effect of IgG on their action

1. To clarify the role of T cells in the development of dextran sulfate sodium (DSS)-induced colitis, T cells from colitis mice were primed with DSS-pulsed macrophages in vitro and then transferred into normal mice. In addition, to determine whether the target cell of immunoglobulin G (IgG) is the T cell, the extent of T cell proliferation induced by pulsed macrophages was examined after preincubation with IgG. 2. When mice receiving the primed T cells were treated with oral DSS, colitis symptoms were more severe than in animals treated with oral DSS only. This activity of primed T cells was reduced by depletion from the cells of CD4+ but not CD8+ cells. 3. The proliferation of T cells from colitis mice induced by pulsed macrophages was inhibited by T cell preincubation with homologous IgG. 4. The results suggest that CD4+ T cells play an important role in the development of DSS-induced experimental colitis and that IgG may modulate the development of colitis through interaction with pathogenic T cells.     

Why Some Bucky Tubes Would be Metallic?

As a reply to the title question, it has been elucidated that metallic bucky tubes are equivalent to those involving plural numbers of isolated polyacetylene (PA) skeletons (cis-type) arranged either in a helical or non-helical manner on the tube surface. Such helical PA skeletons guarantee the metallic conduction path to the electrons near the Fermi level (spiralons). Control of the flow of these spiralons may open up a stage for nano-technology of the electronic devices such as molecular solenoid applicable to molecular electromagnet, molecular electric generator and so on.     

Amino acids and peptides. XXI. Laminin-related peptide analogs including poly(ethylene glycol) hybrids and their inhibitory effect on experimental metastasis

Laminin-related peptides, Tyr-Ile-Gly-Ser-Arg analogs, were prepared and their inhibitory effects on experimental metastasis were examined. Of the amino acids in the Tyr-Ile-Gly-Ser-Arg sequence, L-Arg was very important and Ile was not essential for the inhibitory effect. To obtain a potent inhibitor of metastasis, hybrids of Tyr-Ile-Gly-Ser-Arg-Gly and 2 types of poly(ethylene glycol) were prepared. The inhibitory effects of the hybrids were more potent than that of Tyr-Ile-Gly-Ser-Arg-Gly.     

Effects of filtration through bleaching media on thiobarbituric acid and carbonyl values of autoxidized soybean oil

Effects of filtration bleaching on thiobarbituric acid values (TAV) and carbonyl values (CV) of autoxidized soybean oil were investigated by using sixteen kinds of bleaching media in order to improve oil quality. The standard activated clay was the most effective in reducing the amounts of aldehydes and ketones in autoxidized soybean oil. From the decreases in TVA and CV and physical and chemical properties of media, it was concluded that decreases of TAV and CV are mainly dominated by the acidity over the highest range, +1.5∼−5.6, rather than the acidity over the lower acid strength ranges, total acidity or specific surface area of media. From the results of chemical composition and acidity over the highest range (+1.5∼−5.6) of the clays and TAV or CV reduction by using the heattreated clays, it was suggested that the acidity over the highest range originated from the water contained between layers and bound water in the clay.     

Preparation and solution properties of uniform three-arm star poly(methyl methacrylate)

Syndiotactic (st-) poly(methyl methacrylate) (PMMA) with a hydroxy group at the chain end (st-PMMA-OH) was prepared by st-living polymerization with t-C₄H₉Li/(n-C₄H₉)₃Al in toluene at -78°C. The resulting st-PMMA-OH was fractionated into uniform polymers by means of supercritical fluid chromatography. Uniform st-PMMA-OH with degree of polymerization of 26 was reacted with 1,3,5-benzenetricarbonyl trichloride as a coupling agent and the three-arm star polymer uniform with respect to branch length was isolated from the reaction mixture by the aid of gel permeation chromatography (GPC). Viscometric property of the uniform star PMMA was studied in some detail by using a GPC-differential viscometer.