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  • 1
    Electronic Resource
    Electronic Resource
    Reactive polymers, 5Part 4, cf.9. Synthesis of a 2,3-epoxypropyl ethyl maleate/fumarate mixture and its copolymerization with styrene and ethylene (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 172 (1973), S. 97-106 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aus Äthyl-kaliummaleat und 1-Chlor-2,3-epoxypropan wurde ein Gemisch aus Äthyl-2,3-epoxypropylmaleat und -fumarat (4) erhalten.4 wurde mit Styrol copolymerisiert, und für die Monomeren wurden die folgenden Parameter gefunden: r1 = 0,30 und r2 = 0,05 (M1 = Styrol, M2 = Ester 4). Für Q und e wurden die Werte 0,55 bzw. 1,28 bestimmt. Copolymerisationen von 4 mit Äthylen wurden durchgeführt, um die chemische Reaktivität von Polyäthylen zu verbessern. Diese wurde in einer homogenen Reaktion mit Dibutylamin untersucht. Die beobachteten kinetischen Daten lassen sich in zwei Konstanten ausdrücken: k0 (die nicht katalytische Geschwindigkeitskonstante) = 1,75 · 10-5 dm3 mol-1 s-1 und kc (die produktinduzierte katalytische Geschwindigkeitskonstante) = 2,25 · 10-2 dm6 mol-2 s-1 in DMF bei 70°C.
    Notes: A mixture of 2,3-epoxypropyl ethyl maleate and fumarate (4) was obtained from ethyl potassium maleate and 1-chloro-2,3-epoxy propane.Copolymerization of 4 with styrene was carried out and the monomer reactivity ratios were found to be r1 = 0,30 and r2 = 0,05 (M1: styrene, M2: ester 4). Q and e values were found to be 0,55 and 1,28, respectively. Copolymerizations of 4 with ethylene were performed to improve the chemical reactivity of polyethylene, and the reactivity was studied by means of a homogeneous reaction with dibutylamine. The observed kinetic data may be divided into two parts: ko (non-catalytic rate constant) = 1,75 · 10-5 dm3 mol-1 s-1, kc (product-induced catalytic rate constant) = 2,25 · 102 dm6 mol-2 s-1 in DMF at 70°C.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021720108
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  • 2
    Electronic Resource
    Electronic Resource
    Studies on sublimation of disperse dye out of dyed polymers. I. Rate of sublimation and amorphous transition points of poly(ethylene terephthalate) (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 551-572 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Four samples of poly(ethylene terephthalate) film of various crystallinities and orientation were dyed with p-nitroaniline and disperse dyes. When these films were heated under a 2-3 × 10-3 mm Hg vacuum at a specified temperature T, the dye sublimed out of the dyed specimen. The amount (Mt/M∞) of sublimed dye is in linear proportion to the square root of the sublimation time, t½, where Mt and M∞ are the amounts of dye sublimed for times t and t = ∞. The diffusion coefficient D, calculated from the slope of the above plot, is independent of the dye concentration of the film.When log D is plotted against 1/T°K over the temperature range 320-520°K, the relation is composed of two to four intersecting lines with the slope decreasing with elevation of temperature and with the breaks at about 89°-98°, 122°-135°, 155° and 175°-176°C. These breaks are the amorphous transitions: the first is the glass transition temperature Tg, the second and the fourth are the amorphous transitions corresponding to the crystalline transition points, i.e., the cold crystallization temperature and the smectic-triclinic transition temperature. With some exceptions, these amorphous transitions are found also by dilatometry and electrical conductivity measurements. The apparent activation energy for diffusion decreases from about 100 kcal/mole for the glass state to 22-24 kcal/mole for the region above 180°C. The activation energy for each region changes slightly with the size of dye molecule and the crystallinity and orientation of the film.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1970.070140304
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  • 3
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    Redox regulation of germline and vulval development in Caenorhabditis elegans (2003)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2003-12-06
    Description: In vitro studies have indicated that reactive oxygen species (ROS) and the oxidation of signaling molecules are important mediators of signal transduction. We have identified two pathways by which the altered redox chemistry of the clk-1 mutants of Caenorhabditis elegans acts in vivo on germline development. One pathway depends on the oxidation of an analog of vertebrate low density lipoprotein (LDL) and acts on the germline through the Ack-related tyrosine kinase (ARK-1) kinase and inositol trisphosphate (IP3) signaling. The other pathway is the oncogenic ras signaling pathway, whose action on germline as well as vulval development appears to be modulated by cytoplasmic ROS.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shibata, Yukimasa -- Branicky, Robyn -- Landaverde, Irene Oviedo -- Hekimi, Siegfried -- New York, N.Y. -- Science. 2003 Dec 5;302(5651):1779-82.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, Quebec, Canada, H3A 1B1.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14657502" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Apolipoproteins B/genetics/metabolism ; Base Sequence ; Caenorhabditis elegans/genetics/*growth & development/*metabolism ; Caenorhabditis elegans Proteins/chemistry/genetics/metabolism ; Cholesterol/metabolism ; Cloning, Molecular ; Disorders of Sex Development ; Female ; Inositol Phosphates/metabolism ; Lipoproteins, LDL/*metabolism ; Molecular Sequence Data ; Mutation ; Oxidation-Reduction ; Phenotype ; Protein-Tyrosine Kinases/metabolism ; RNA Interference ; Reactive Oxygen Species/*metabolism ; Transcription Factors/genetics/metabolism ; Vulva/growth & development ; ras Proteins/genetics/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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