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  • 11
    Electronic Resource
    Electronic Resource
    Carbon-13, proton, and deuteron NMR observation of trideuterated cyclopropylmethyl-cyclobutyl carbocation, a configurationally stable species (1984)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 7280-7282 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00335a089
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  • 12
    Electronic Resource
    Electronic Resource
    Free radicals in lipid bilayers: new probes of lipid radical dynamics (1984)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 813-814 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00315a070
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  • 13
    Electronic Resource
    Electronic Resource
    Polycarbonate-Carbon Nanofibers Composites: An Electron Spin Resonance Study (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 47-50 (June 2008), p. 1165-1168 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Polycarbonate - carbon nanofibers, containing various concentrations of filler rangingfrom 0 % to 10 % wt. have been investigated by electron spin resonance. The as obtained electronspin resonance spectra are complex due to the overlap of several resonances originating from theconducting electrons delocalized over the metallic domains of nanotubes, from the free radicalsgenerated within the polymeric matrix during the processing step, from insulating graphite particles,and from catalyst residues (observed as magnetic impurities).The effect of the filler on the resonance line shape is analyzed in detail. The shape of resonancespectrum demonstrates that the resonance line located near g=2.00 originates from conductingelectrons delocalized over the metallic domains of nanotubes. Thos line was accurately fitted by aLorentzian line shape
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/41/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.47-50.1165.pdf
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  • 14
    Electronic Resource
    Electronic Resource
    Radiovision (1928)
    [s.l.] : Nature Publishing Group
    Nature 122 (1928), S. 809-810 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] IN steering clear of the hybrid ‘television’ in a note in NATURE of Nov. 3, p. 704, you lead to a confusion of terms which, unfortunately, is common. 'Radiovision ' is suitable for ' television ' by radio, but ' television ' can also be transmitted by telegraph or telephone line. Near ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/122809c0
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  • 15
    Electronic Resource
    Electronic Resource
    Haloaziridines. 2. Synthesis and pyrolysis of some gem-dichloroaziridines (1978)
    s.l. : American Chemical Society
    The @journal of organic chemistry 43 (1978), S. 1346-1350 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00401a013
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  • 16
    Electronic Resource
    Electronic Resource
    Synthesis of polycarbonate containing in-chain 4-N,N-dimethylamino-4′-nitrostilbene via ring-opening polymerization (1996)
    Springer
    Polymer bulletin 37 (1996), S. 573-579 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary We have successfully synthesized a new NLO chromophore based on 4-N,N-dimethylamino-4′-nitrostilbene which contains bisphenol functionality for polycarbonate preparation. Chromophore-4 was used to make macrocyclic carbonate oligomers and the oligomers were converted to polycarbonate via ring-opening polymerization in solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296601
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  • 17
    Electronic Resource
    Electronic Resource
    Rates of carbonate bond formation: Implications for macrocyclizationDedicated to Professor Maurice Morton to commemorate the establishment of the Maurice Morton Institute of Polymer Science at the University of Akron. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 161-164 
    Details
    ISSN: 0959-8103
    Keywords: polymerization mechanism ; polymerization kinetics ; carbonate macrocyclization ; polycarbonate ; stopped-flow spectroscopy ; 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: High yields of cyclic oligomeric carbonates can be prepared using an amine-catalyzed reaction of bisphenol A-bischloroformate. We have studied the mechanistic aspets of this carbonate macrocyclization by the isolated study of key chemical events. Using stopped-flow FT-IR spectroscopy, we have found that the rate of carbonate formation between the intermediate acyl ammonium salt and 4-isopropylphenol is the same for the acyl ammonium salt derived from tri-n-butylamine, triethylamine and diethylmethylamine. Previously, we found that conversion of acyl ammonium salt to urethane was also insensitive to amine structure while the formation of acyl ammonium salt is profoundly dependent on amine structure. These results are consistent with a mechanism in which the selectivity toward macrocyclization versus linear oligomer or high polymer formation is related to acyl ammonium salt concentration.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330206
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  • 18
    Electronic Resource
    Electronic Resource
    Mechanistic studies of carbonate macrocyclization (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 741-746 
    Details
    ISSN: 0887-624X
    Keywords: polymerization mechanism ; polymerization kinetics ; carbonate macrocyclization ; polycarbonate ; stopped-flow spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of phenylchloroformate (PCF) reactions have been used to model some of the key chemical events in carbonate macrocyclization. Three reactions have been studied using stopped-flow FT-IR spectroscopy: formation of acyl ammonium salt from PCF and three different trialkylamines, the conversion of acyl ammonium salt to urethane, and the condensation reaction between acyl ammonium salt and 4-isopropylphenol. The rate dependence was studied for triethylamine (TEA), diethylmethylamine (DEMA) and tri-n-butylamine (TBA) at 0°C in anhydrous CH2Cl2. The reactivity order for acyl ammonium salt formation for TBA: TEA: DEMA is 1 : 2.7 : 〉444. By contrast, condensation and urethane formation are not sensitive to the structure of the amine. The rate of condensation is comparable to the rate of acyl ammonium salt formation for TEA and TBA, while the rate of urethane formation is the slowest process for all three amines. These results are consistent with the view that the yield of macrocyclic polycarbonates is related to the concentration of the acyl ammonium salt. The optimum amine concentration for obtaining high yields of cyclics varies with the amine structure and parallels the difference in the rates of acyl ammonium salt formation. © 1994 John & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320412
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  • 19
    Electronic Resource
    Electronic Resource
    Contact activation of the plasma coagulation cascade. I. Procoagulant surface chemistry and energy (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1005-1016 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Contact activation of the intrinsic pathway of porcine blood plasma coagulation is shown to be a steep exponential-like function of procoagulant surface energy, with low activation observed for poorly water-wettable surfaces and very high activation for fully water-wettable surfaces. Test procoagulants studied were a system of oxidized polystyrene films with varying wettability (surface energy) and glass discs bearing close-packed self-assembled silane monolayers (SAMs) with well-defined chemistry consisting of 12 different terminating chemical functionalities. A monotonic trend of increasing coagulation activation with increasing water wettability was observed for the oxidized polystyrene system whereas results with SAM procoagulants suggested a level of chemical specificity over and above the surface energy trend. In particular, it was noted that coagulation activation by SAMs terminated with —CO2H was much higher than anticipated based on surface wettability whereas —NH3⊕-terminated SAMs exhibited very low procoagulant activity. SAMs terminated in —(CH2)2(CF2)7CF3 behaved as anticipated based on surface energy with very low procoagulant activity and did not exhibit special properties sometimes attributed to perfluorinated compounds. Quantitative ranking of the inherent coagulation activation properties of procoagulant surfaces was obtained by application of a straightforward phenomenological model expressed in a closed-form mathematical equation relating coagulation time to procoagulant surface area. Fit of the model with a single adjustable parameter to experimental measurements of porcine platelet-poor plasma coagulation time was very good, implying that assertions and simplifications of the model adequately simulated reality. Two important propositions of the model were that (1) the number of putative “activating sites” scaled linearly with procoagulant surface area, and (2) contact activation of the plasma coagulation cascade was catalytic in the sense that these activating sites were not consumed or “poisoned” by irreversible or slowly reversible protein adsorption during coagulation. An extension of the coagulation model proposed that procoagulant activation properties scale exponentially with the surface density of polar (acid-base) sites, which, in turn, was related to procoagulant wettability. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290813
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  • 20
    Electronic Resource
    Electronic Resource
    Contact activation of the plasma coagulation cascade. II. Protein adsorption to procoagulant surfaces (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1017-1028 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A study of blood protein adsorption to procoagulant surfaces utilizing a coagulation time assay, contact angles, Wilhelmy balance tensiometry, and electron spectroscopy (ESCA) is presented. Using a new contact angle method of measuring protein adsorption termed “adsorption mapping” it was demonstrated that protein-adsorbent surfaces were inefficient activators of the intrinsic pathway of the plasma coagulation cascade whereas water-wettable, protein-repellent surfaces were efficient procoagulants. Repeated use of fully water-wettable (spreading) glass procoagulants in the coagulation time assay demonstrated that putative “activating sites” were not consumed in the coagulation of platelet-poor porcine plasma. Furthermore, these procoagulant surfaces retained water-wettable surface properties after incubation with blood proteins and saline rinse. The interpretation of these observations was that plasma and serum proteins were not adsorbed to water-wettable surfaces. However, ESCA of these same surfaces revealed the presence of a thin protein layer. Wilhelmy balance tensiometry resolved these seemingly divergent observations by demonstrating that protein was “associated” with a bound hydration layer, but not formally adsorbed through a surface dehydration or ionic interaction mechanism. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290814
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