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  • 1990-1994  (6)
  • Polymer and Materials Science  (4)
  • DNA ploidy  (1)
  • Pinaceae  (1)
  • 1
    Electronic Resource
    Electronic Resource
    The 5S RNA genes inPinus radiata and the spacer region as a probe for relationships betweenPinus species (1992)
    Springer
    Plant systematics and evolution 183 (1992), S. 209-221 
    Details
    ISSN: 1615-6110
    Keywords: Gymnosperms ; Pinaceae ; Pinus radiata ; 5S RNA genes ; spacer variants ; phylogenetic groups
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 5S RNA genes inPinus radiata occur in two size classes of about 850 and 525 bp in length. Representatives from both the long and short size classes were cloned and sequenced. The primary difference in the two size classes was shown to be a 330 bp insertion in the spacer region of the long units. Within an individual breeding clone ofP. radiata there was some sequence heterogeneity between representatives of the short class. The 5S RNA genes in thirty pine species were characterised using either a clone of the short size class or a subclone of the 330 bp insertion characterizing the long size class. Eleven species of subg.Strobus were examined and all lacked the long type of unit of radiata pine. The New World species of subg.Pinus all had both short and long units whereas the Old World species had long units. The implications of these results for the evolution of the 5S DNA sequences and the phylogenetic relationships withinPinus are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940804
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  • 2
    Electronic Resource
    Electronic Resource
    Cellular effects of tamoxifen in primary breast cancer (1991)
    Springer
    Breast cancer research and treatment 20 (1991), S. 117-123 
    Details
    ISSN: 1573-7217
    Keywords: primary breast cancer ; tamoxifen ; tumour antigen ; oestrogen receptor ; DNA ploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have investigated the effect of tamoxifen on the biological characteristics of the primary tumour in 33 patients with breast cancer. All patients had pre-treatment biopsy of the primary breast cancer and subsequent trucut biopsy of the primary tumour after 1–4 months on tamoxifen therapy. The staining patterns in the primary tumour of each of the tumour antigens 115D8, DF3, NCRC-11, and carcinoembryonic antigen (CEA) were unaffected by tamoxifen therapy: there was 16%–31% change before vs. during tamoxifen therapy, but this did not reach significance for any of the four antigens. Comparison of the pattern of staining between the four antigens showed 115D8, DF3, and NCRC-11 to be similar to each other both before and during tamoxifen therapy. All three antigens were significantly different from the staining pattern shown by CEA before and during therapy. Tumour antigen expression pre-treatment did not correlate with therapeutic response for any of the four antigens. However, NCRC-11 staining during tamoxifen therapy did correlate with response (p=0.004). There was no significant difference in oestrogen receptor status before and during tamoxifen therapy, both of which correlated with response. DNA ploidy of the tumour before tamoxifen did not correlate with response to therapy, but there was a weak correlation between response and DNA ploidy measured during tamoxifen therapy. In only a minority of tumours (up to 30%) did tamoxifen exert an effect on the biological characteristics studied. Changes in these biological markers were mainly in tumours which responded to tamoxifen, and the changes seen were a tendency to greater expression of differentiation antigens. It is uncertain whether these changes are a primary or a secondary effect of tamoxifen with respect to inducing tumour response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01834641
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  • 3
    Electronic Resource
    Electronic Resource
    Rate of electropolymerization of N,N'dimethyl acrylamide in aqueous sulfuric acid solution (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 583-592 
    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: Electropolymerization of N,N-dimethylacrylamide has been performed in aqueous sulfuric acid solution, using unsized AS-4 graphite fibers as the working electrode. The electro-polymerized poly (N,N-dimethylacrylamide) deposited on the surface of the graphite fiber working electrode. The formation of poly (N,N'dimethyl acrylamide) was inhibited by hydroquinone. The addition of about 0.05 moles of hydroquinone to the reaction solution resulted in about a 90% decrease in the weight gain of fibers, in agreement with the proposed free radical mechanism of aqueous electropolymerization. The rate of electropolymerization varied with the initial monomer concentration, current density, and sulfuric acid concerntration, raised to the power of 1.3, 0.42, and 0.07, respectively, that is, Rp ∝ [M]1.3-Cd0.42 [H2SO4]0.07. A mathematical model, based upon free radical polymerization kinetics, is discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490404
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  • 4
    Electronic Resource
    Electronic Resource
    Aqueous electropolymerization of polyacrylamide onto AS-4 graphite fibers (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 2237-2247 
    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: Constant current electropolymerization of acrylamide was initiated on the surfaces of AS-4 graphite fibers. Electropolymerization was performed using an aqueous solution of acrylamide dissolved in dilute sulfuric acid solution. The progress of electropolymerization was followed by measuring the weight of polyacrylamide deposited onto the surfaces of a unit weight of graphite fiber per unit time. The rate of electropolymerization was obtained from the slope of the linear region of the polymer weight gain vs. electropolymerization time curve. The rate of electropolymerization onto AS-4 graphite fiber surfaces was found to depend on the initial monomer concentration, sulfuric acid concentration, and current density raised to the powers of 1.67, 0.02, 0.54, respectively. Molecular weight measurements on the electropolymerized polyacrylamide were done by solution viscometry. Number average molecular weights of 430,000, 220,000, and 193,000 were obtained for polyacrylamide, electropolymerized at 1 mA/g, 50 mA/g, and 100 mA/g respectively, consistent with classical radical polymerization kinetics.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070431213
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  • 5
    Electronic Resource
    Electronic Resource
    Thermoplastic matrix composites by aqueous electrocopolymerization onto graphite fibers (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 735-749 
    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: Electrocopolymerization of 3-carboxyphenyl maleimide and styrene onto Hercules AS-4 graphite fiber surfaces has been successfully carried out from an aqueous solution containing monomers and dilute sulfuric acid. Initiation of copolymerization of the monomers dissolved in a small amount of dimethylacetamide is achieved by constant-current electrolysis in the cathodic chamber of a three-compartment electrolysis cell. Polymerization is initiated at the fiber surfaces; little polymer is formed in the cell solution. Electrocopolymerization is very consistent and rapid. The amount of polymer increases predictably with increasing comonomer concentration and current density. Using a 0.4 M (1 : 1) comonomer concentration, 0.0125 M sulfuric acid solution, and a current density of 20 mA/g, more than 60 wt % of copolymer coating per unit weight of graphite fibers is obtained within thirty minutes. Thermal gravimetric analysis showed the copolymer to be very stable at elevated temperatures and has initial and final decomposition temperatures of 430 and 520°C, respectively. The glass transition temperature measurement of the copolymer coatings was carried out by differential scanning calorimetry. A single glass transition temperature was obtained of about 210°C for most samples. The glass transition temperature of the copolymers did not change significantly with changing comonomer feed composition. Functional group and compositional analysis of the copolymer was done by FTIR spectroscopy. The copolymer composition remained relatively the same for copolymers made from different styrene/3-carboxyphenyl maleimide feed composition, confirming a strong tendency toward alternation for the system.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070410321
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanism of the electrocopolymerization of styrene and N-(3-carboxyphenyl)maleimide onto graphite fibers in aqueous solution (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 93-104 
    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: Electrochemical copolymerization of styrene and N-(3-carboxyphenyl)maleimide was performed in an aqueous sulfuric acid solution using AS-4 graphite fibers as the working electrode. Cyclic voltammetric analysis results suggest radical initiation of polymerization via the reduction of the N-(3-carboxyphenyl)maleimide and sulfuric acid. Radical chain electrocopolymerization was strongly suggested by the inhibition of chain growth in the presence of hydroquinone and 2,2-diphenylpicrylhydrazyl (DPPH). Compositional analysis of copolymers and reactivity ratios rs ∼ 0.014 and rm ∼ 0.041 for styrene and N-(3-carboxyphenyl)maleimide [N-(3-CMI)], respectively, confirmed a 1 : 1 alternating electrocopolymerization. Kinetic analysis shows a first- and 1/2-order dependence of the rate of chain growth on initial monomer concentration and initiator concentration, respectively. A model incorporating these data is presented. © 1993 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070470112
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