Grafting of poly(acrylic acid) onto polyethylene filament and its distribution

Radiation-induced simultaneous grafting of acrylic acid onto high density polyethylene filament is carried out with aqueous solution of acrylic acid in the absence and presence of ethylene dichloride. Distribution of grafted poly(acrylic acid) is studied by two methods. One is optical microscopic investigation of cross sections of dyed filament, and the other is electron probe microscopy of acrylic acid graft filament after conversion to calcium acrylate. Qualitative study with WAXS is also carried out. Grafting begins from the surface or periphery and proceeds, with sharp boundary, to the core. The reaction takes place only in the amorphous part of polyethylene. The percent graft in the grafted part is homogeneous and rather high from the beginning of the reaction; it is true that additional grafting to the already grafted part takes place, but it is not so noticeable.     

Kinetics of emulsion copolymerization. III. Prediction of the average number of radicals per particle in an emulsion copolymerization system

This paper develops a simple method for predicting the average number of total radicals per particle and their kinds in emulsion copolymerization systems by extending emulsion homopolymerization theories so far published. The validity and utility of this method is demonstrated by using the experimental data obtained in the emulsion copolymerization of styrene and methyl methacrylate.     

Effective thermoelastic constants of short-fiber composites

This paper studies the effective thermal stress and thermal expansion coefficients of unidirectional short-fiber composites. The thermoelastic constants in the form of infinite series are obtained based upon the known local elastic field solution derived by the perturbation expansion of the Green's tensor function. Approximations of the series expansions are presented for multi-phase short-fiber composites such as hybrids. The results are further reduced to binary systems and the upper and lower bound predictions of effective thermoelastic constants are given.     

Presence of m3 subtype muscarinic acetylcholine receptors and receptor-mediated increases in the cytoplasmic concentration of Ca2+ in Jurkat, a human leukemic helper T lymphocyte line

Recent studies have demonstrated the presence and the regulatory function of several neurotransmitters in the immune system. In the present study, we examined the presence of acetylcholine receptors, using pharmacological and molecular biological assays, and their transmembrane control and functions, using a biochemical assay, in a cloned human leukemic helper T lymphoma cell line, Jurkat. Several muscarinic agonists, such as acetylcholine, carbachol, muscarine, and oxotremorine-M (Oxo-M), at 100 microM caused a transient elevation of the free cytosolic Ca2+ concentration ([Ca2+]i), in contrast to the tonic elevation of [Ca2+]i induced by 10 micrograms/ml phytohemagglutinin (PHA). It appeared that the elevation induced by Oxo-M, the most potent [Ca2+]i elevator, was more effectively inhibited by p-fluorohexahydrosiladifenidol hydrochloride (p-F-HHSiD) and 4-diphenylacetoxy-N-methylpiperidine methiodine than by pirenzepine and 11-2[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro- 6H-pyrido[2,3-b] [1,4]benzodiazepine-6-one (AF-DX 116), suggesting that a pharmacological M3 subtype of muscarinic receptors is involved in the elevation of [Ca2+]i. Northern blot analysis showed that the m3 type of receptors are expressed in Jurkat cells. Scatchard analysis of [3H]quinuclidinyl benzilate binding to intact cells indicated a Kd of 14.1 nM and a Bmax of 45,370 binding sites/cell. [3H]Quinuclidinyl benzilate binding to cell membranes was also inhibited by p-F-HHSiD rather than by pirenzepine and AF-DX 116. Oxo-M induced formation of inositol trisphosphate, and 5'-O-(2-thio)diphosphate inhibited the formation. Cholera toxin treatment inhibited the PHA-induced [Ca2+]i rise but did not affect the Oxo-M-induced rise. Neither pertussis nor butulinus (type C) toxin affected the rise induced by Oxo-M or PHA. Thus, bacterial toxin-insensitive GTP-binding proteins seem to be involved in the Oxo-M-induced increase in [Ca2+]i. Treatment with 12-O-tetradecanoylphorbol 13-acetate abolished the Oxo-M-induced [Ca2+]i rise but did not affect that induced by PHA. m3 Muscarinic receptors thus appear to cause Ca2+ mobilization from intracellular stores via bacteria toxin-insensitive GTP-binding proteins, phospholipase C activation, and inositol trisphosphate formation in Jurkat cells. Protein kinase C seems to negatively modulate the m3 receptor system.     

Application of a linear alkylbenzene sulfonate biosensor to river water monitoring

A novel whole cell biosensor was constructed for the detection of anionic surfactants in aquatic environments. The analysis was rapid, convenient and did not require organic reagents. In this report, the application of this sensor to river water samples was investigated when applied to environmental samples; other organic substances present in river water may affect the measurement of linear alkylbenzene sulfonates. In order to deal with this problem, a correction system was developed using whole cells of Trichosporon cutaneum. This system was applied to in situ 24 h continuous monitoring in the Saka river.