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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 3403-3408 
    ISSN: 0887-624X
    Keywords: star-shaped ; poly(THF) ; ion-coupling ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The prepoly(tetrahydrofuran) [poly(THF)] capped with hydroxyl and tetrahydrothiophenium groups was prepared using tetrahydrothiophene to terminate the living cationic polymerization of THF initiated by BF3·OEt2 and epichlorohydrin (ECH) at low conversion. Well-defined star-shaped poly(THF) polyols were synthesized by an ion-coupling reaction of the prepoly(THF) with tri- or tetrafunctional benzenecarboxylates, respectively, and this process proceeded by precipitation when the solution of the prepolymer in THF was added to an aqueous solution containing an excess of the corresponding coupling reagent. GPC studies showed that all of the carboxylate groups of every coupling reagent molecule took part in the ion-coupling reaction simultanously. This was confirmed by IR spectra. Almost all of the prepolymers were coupled to form star polymers after repeating the precipitation four times. 1H-NMR illustrated that both the star-shaped polymers and the prepolymers contained primary and secondary hydroxyl end groups. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3403-3408, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2899-2903 
    ISSN: 0887-624X
    Keywords: cationic ring-opening polymerization ; poly(1,3-dioxepane) triol ; 2,2-bis(hydroxymethyl)butanol ; transacetalization ; activated monomer mechanism ; activated chain mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic polymerization of 1,3-dioxepane (DOP) initiated by triflic acid was carried out in the presence of 2,2-bis(hydroxymethyl)butanol (BHMB). The structure and molecular weight of the products were characterized by GPC and NMR spectra. The results showed that molecular weight of the polyacetal obtained could be controlled by the initial mole ratio of DOP/BHMB. GPC showed that as the mole ratio of BHMB/DOP increased, the content of cyclic oligomers also increased. Proton, 13C and 2D HMQC-fg NMR demonstrated that no hydroxymethyl group of BHMB appeared as an end group. It was also illustrated by proton NMR that some BHMB units existed in cyclic oligomers. The mechanism of formation of cyclic oligomers was discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2899-2903, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 485-489 
    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: Photosensitive polyimide BTDA-3MPDA was modified by UV irradiation. The structure of UV-irradiated polyimides was investigated by FTIR and gel fraction measurements. The results showed that longer UV exposure time resulted in a higher extent of crosslinking. The gas permeabilities of hydrogen, oxygen and nitrogen through UV-irradiated polyimides were characterized in a temperature range from 30°C to 90°C. Photocrosslinking resulted in a sharp decline in gas permeability for hydrogen, oxygen, and nitrogen through polyimide in the initial stage of photocrosslinking. Then, as the crosslinked benzophenone percentage amounted to 28-38% for hydrogen, 17-31% for oxygen and 3-28% for nitrogen, the gas permeabilities showed another sharp decline. Gas permselectivity increased significantly with the progress of photocrosslinking, and it can be adjusted in a wide range by controlling the extent of crosslinking. Arrhenius plots of gas permeability for hydrogen and oxygen through UV-irradiated polyimides are straight lines; for nitrogen, however, change in the slope of the straight line is observed and activation energies for hydrogen and oxygen permeation show abrupt increases when crosslinked benzophenone percentage amounts to about 30%. UV-irradiated polyimides with simultaneous high gas permeability and permselectivity make them ideal candidate materials for gas separation. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 2613-2622 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The cationic polymerization of 1,3-dioxepane (DOP) initiated with trifluoromethanesulfonic acid (I) in the presence of ethylene glycol (EG) was investigated. At sufficiently low concentration of the initiator ([I] 〉 0.01 mol/L vs. [EG] 〈 0.20 mol/L), the molecular weights of the obtained polyacetal oligodiols are controlled by the mole ratio of consumed DOP to initial EG. Gel-permeation chromatography studies revealed that the concentration of cyclic oligomers in the products are negligible. The mechanism of the polymerization was investigated by means of kinetic studies. The results showed that the polymerization proceeds according to the active chain end mechanism (ACF) in combination with the activated monomer mechanism (AM); thus the cyclic oligomer in the obtained polymer is reduced, and intermolecular chain transfer to EG in ACE is dominant. It was also demonstrated that as [DOP]2[I]/[EG] decreases the contribution of ACE to the polymerization decreases and that of AM increases. In addition, 1H and 13C NMR data illustrated that each macromolecule of polyDOP oligodiols contained one EG unit on average and that no EG end groups exist.
    Additional Material: 5 Ill.
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  • 5
    Publication Date: 2012-01-08
    Description: Environmental Science & Technology DOI: 10.1021/es2032218
    Print ISSN: 0013-936X
    Electronic ISSN: 1520-5851
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
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  • 6
    Publication Date: 2013-07-12
    Description: Environmental Science & Technology DOI: 10.1021/es401632r
    Print ISSN: 0013-936X
    Electronic ISSN: 1520-5851
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
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  • 7
    Publication Date: 2013-07-31
    Description: Sortilin, a Golgi sorting protein and a member of the VPS10P family, is the co-receptor for proneurotrophins, regulates protein trafficking, targets proteins to lysosomes and regulates low density lipoprotein metabolism. The aim of this study was to investigate the expression and regulation of sortilin in Alzheimer's disease (AD). A significantly increased level of sortilin was found in human AD brain and in the brains of 6-month-old APPswe/PS1dE9 transgenic mice. Aβ 42 enhanced the protein and mRNA expression levels of sortilin in a dose- and time-dependent manner in SH-SY5Y APP695 cells, but had no effect on sorLA. In addition, proBDNF also significantly increased the protein and mRNA expression of sortilin in these cells. The recombinant extracellular domain of p75 NTR (P75ECD-FC), or the antibody against the extracellular domain of p75 NTR , blocked the upregulation of sortilin induced by Aβ, suggesting that Aβ 42 increased the expression level of sortilin and mRNA in SH-SY5Y via the p75 NTR receptor. Inhibition of ROCK, but not JNK, suppressed constitutive and Aβ 42 -induced expression of sortilin. In conclusion, this study shows that sortilin expression is increased in the AD brain in human and mice and that Aβ 42 oligomer increases sortilin gene and protein expression through p75 NTR and RhoA signaling pathways, suggesting a potential physiological interaction of Aβ 42 and sortilin in Alzheimer's disease. This article is protected by copyright. All rights reserved.
    Print ISSN: 0022-3042
    Electronic ISSN: 1471-4159
    Topics: Medicine
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  • 8
    Publication Date: 2015-03-03
    Description: Catheter-related infection makes up a large part of hospital infection and contributes 80% to all nosocomial urological infection, costing hundreds of millions dollar per year for treatment. Biodegradable hydrophilic material incorporating antibiotic substance is a promising way to prevent catheter-related infection. And antimicrobial peptide seems an optimal drug for its desirable antibiotic effect. In the current research, we produced a new kind of antibiotic material by incorporating antimicrobial peptide Bmap-28 with polyurethane PEGU25 and tested its effect on Proteus mirabilis in vitro. Compared with the control group, PEGU25 membrane incorporating Bmap-28 had a significant lower bacteria load after co-cultured with the Proteus mirabilis. And its antibiotic effect could be observed throughout the whole 7-day test. Also the Bmap-28 membrane could delay catheter obstruction caused by encrustation. Our findings reveal that PEGU25 incorporating Bmap-28 can well inhibit bacterial biofilm formation of common pathogens for catheter-related urinary tract infection in vitro, which makes it a promising antibiotic material for medical tubes for urology. Scientific Reports 5 doi: 10.1038/srep08634
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
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  • 9
    Publication Date: 2014-10-10
    Description: The health impacts of polycyclic aromatic hydrocarbons (PAHs), the most concerning organic pollutants, depend not only on the locations and strengths of emission sources, but also on individual susceptibility. Moreover, trans-boundary transport makes them a global concern. In this study, a comprehensive analysis of the global health impacts of polycyclic aromatic hydrocarbons (PAHs) in ambient air is presented. Model resolution is critical in exposure modelling. Globally, incremental lifetime lung cancer risk (ILCR) induced by ambient PAH exposure is 3.1 × 10−5. If the individual susceptibility was not taken into consideration, the overall risk would be underestimated by 55% and the proportion of highly vulnerable population would be underestimated by more than 90%. Emphasizing on individual susceptibility, our study provides an instrumental revision of current risk assessment methodology. In terms of lung cancer risk, the most important sources are combustion of biomass fuels (40%) and fossil fuels (14%) in the residential/commercial sector, coke (13%) and aluminium (12%) production, and motor vehicles (9%). PAHs can travel long distance globally especially within the Eurasian continent. Still, the risk is dominantly contributed by local. Scientific Reports 4 doi: 10.1038/srep06561
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
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  • 10
    Publication Date: 2013-06-29
    Description: Environmental Science & Technology DOI: 10.1021/es4005398
    Print ISSN: 0013-936X
    Electronic ISSN: 1520-5851
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
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