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  • 1995-1999  (10)
  • 1955-1959
  • 1900-1904
  • 1997  (10)
  • Chemistry  (10)
  • polycondensation  (2)
  • Inorganic Chemistry
  • mass spectrometry
  • 1
    Electronic Resource
    Electronic Resource
    Polyamides incorporating phosphine oxide groups. III. Polymerisation of bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide with dicarboxylic acids (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2865-2870 
    Details
    ISSN: 0887-624X
    Keywords: phosphine oxide ; aromatic-aliphatic polyamides ; polycondensation ; thermal properties ; fire retardant materials ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new polymerisation monomer bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide (p-BAPPO) was prepared in good yield by the nucleophilic substitution reaction between bis(4-fluorophenyl)phenylphosphine oxide and a large excess of 1,2-diaminoethane. Five novel polyamides, incorporating phosphine oxide groups within the polymer backbone were synthesised by the condensation reaction of p-BAPPO with a series of aromatic and aliphatic dicarboxylic acids. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Glass transition temperatures in the 180-215°C range were recorded. Although we observed their thermooxidative stabilities (5% weight loss 〉 345°C) to be lower by 40-70°C than those previously found for wholly aromatic polyamides with phosphine oxide groups within the parent chain, char yields upon prolonged heating at 650°C were still excellent (26-38%). Also, good solubility in aprotic polar solvents was observed for all polyamides synthesised. The new polyamides clearly represent significant progress in the quest for processible fire retardant materials. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2865-2870, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of novel polyxanthenes from poly(arylene ether)s containing benzoyl groups (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2267-2272 
    Details
    ISSN: 0887-624X
    Keywords: poly(arylene ether)s ; pendant benzoyl groups ; polyxanthenes ; Friedel-Crafts cyclization ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(arylene ether)s (3), (4) containing pendant benzoyl groups as precursors for novel polyxanthenes (7), (8) were prepared by nucleophilic substitution reaction of 2,5-difluoro-4-benzoylbenzophenone (1) or 2,5-difluoro-4-(4-dodecylbenzoyl)-4′-dodecylbenzophenone (2) with hydroquinone derivatives in the presence of potassium carbonate in N,N-dimethylacetamide. The polycondensation proceeded smoothly at 165°C and produced poly(arylene ether)s with inherent viscosities up to 0.80 dL/g. The novel polyxanthenes were synthesized via the reduction of poly(arylene ether)s followed by the Friedel-Crafts cyclization of diol polymers. The structure of the polyxanthenes was characterized by 1H-NMR and IR spectroscopies. Polyxanthene 8 was quite soluble in chloroform and THF. The 10% weight loss temperature of polyxanthene 7 was 510°C in nitrogen and it was 90°C higher than the corresponding poly(arylene ether) 3. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2267-2272, 1997
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and properties of new crystalline poly(arylene ether)s containing pendant benzoyl groups (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 605-611 
    Details
    ISSN: 0887-624X
    Keywords: poly(arylene ether)s ; pendant benzoyl groups ; 2,5-difluoro-4-benzoyl-benzophenone ; hydroquinone derivatives ; thermostability ; semi-crystalline polymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(arylene ether)s (3) containing pendant benzoyl groups were prepared by the aromatic substitution reaction of 2,5-difluoro-4-benzoylbenzophenone (2) with hydroquinone (1a) and methylhydroquinone (1b) in the presence of potassium carbonate in N,N-dimethylacetamide. The polycondensation proceeded smoothly at 165°C and produced poly(arylene ether)s with inherent viscosities up to 0.8 dL/g. The polymer (3b) derived from methylhydroquinone was quite soluble in common organic solvents and could be processed into uniform films from solutions. On the other hand, the polymer (3a) derived from hydroquinone was only soluble in pentafluorophenol and methanesulfonic acid and had a high crystallinity. These polymers showed 10% weight losses at around 420 and 490°C in nitrogen. Polymer 3b also showed good tensile strength and tensile moduli. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 605-611, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Polyamides incorporating phosphine oxide groups. II. Aromatic polymers containing sulfone functionality (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 493-497 
    Details
    ISSN: 0887-624X
    Keywords: phosphine oxide ; diarylsulfone ; polyamide ; polycondensation ; thermal properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four novel polyamides have been prepared in high yields by the polycondensation reactions of bis(3-carboxyphenyl)- and bis(4-carboxyphenyl)phenylphosphine oxide with 3,3′- and 4,4′-diaminodiphenylsulfone. The thermal properties of these materials were studied using differential scanning calorimetry and thermogravimetric analysis. It was found that the presence of both phosphine oxide and sulfonyl groups within the polymer backbone brought about remarkable modifications in the thermal behavior. Glass transition temperatures 40-50°C lower than those of conventional polyamides i.e., in the range 170-200°C, were recorded. However, we observed greater thermooxidative stability (5% weight loss at 〉410°C) and high char yield upon prolonged heating at 800°C (20-34%). Also, good solubility in polar aprotic solvents was observed for all polyamides together with some solubility in aqueous solvent mixtures, e.g. tetrahydrofuran/water (95:5). © 1997 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Quantum-mechanical calculations of chemical thermodynamics: Practice and limitations (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 2153-2156 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690430825
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  • 6
    Electronic Resource
    Electronic Resource
    Mathematical model for characterization of bacterial migration through sand cores (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 53 (1997), S. 487-496 
    Details
    ISSN: 0006-3592
    Keywords: bacterial chemotaxis ; Escherichia coli ; random motility ; mathematical model ; sand core ; porous media ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The migration of chemotactic bacteria in liquid media has previously been characterized in terms of two fundamental transport coefficients - the random motility coefficient and the chemotactic sensitivity coefficient. For modeling migration in porous media, we have shown that these coefficients which appear in macroscopic balance equations can be replaced by effective values that reflect the impact of the porous media on the swimming behavior of individual bacteria. Explicit relationships between values of the coefficients in porous and liquid media were derived. This type of quantitative analysis of bacterial migration is necessary for predicting bacterial population distributions in subsurface environments for applications such as in situ bioremediation in which bacteria respond chemotactically to the pollutants that they degrade.We analyzed bacterial penetration times through sand columns from two different experimental studies reported in the literature within the context of our mathematical model to evaluate the effective transport coefficients. Our results indicated that the presence of the porous medium reduced the random motility of the bacterial population by a factor comparable to the theoretical prediction. We were unable to determine the effect of the porous medium on the chemotactic sensitivity coefficient because no chemotactic response was observed in the experimental studies. However, the mathematical model was instrumental in developing a plausible explanation for why no chemotactic response was observed. The chemical gradients may have been too shallow over most of the sand core to elicit a measurable response. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 487-496, 1997.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Screen-printed voltammetric sensors for 2-furaldehyde based on nickel-modified and amalgam-stabilized mercury-coated carbon inks (1997)
    Weinheim : Wiley-Blackwell
    Electroanalysis 9 (1997), S. 1353-1359 
    Details
    ISSN: 1040-0397
    Keywords: Screen-printed electrode ; Carbon ink ; Silver ink ; Nickel ink ; Platinum ink ; Mercury-coated ; 2-Furaldehyde ; Transformer oil ; Voltammetry ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article describes a general method for stabilizing microdroplets of mercury on thick-film screen printed electrodes (SPEs). Electrodes modified with nickel metal powder are compared with amalgam stabilized mercury SPEs. Application of the electrodes to the measurement of organic materials is demonstrated by the electrochemical determination of 2-furaldehyde, a marker for power transformer condition monitoring. The electrodes were characterized by cyclic voltammetry and subsequently a square-wave voltammetric method was used to extend the detection limit of the measurement. The resulting cathodic currents for the reduction of 2-furaldehyde was proportional to the concentration of 2-furaldehyde. Plots of 2-furaldehyde concentration against response at a nickel-modified carbon SPE gave linear regions for concentrations in the range 3.7-14.3 ppm (regression equation; Y = 0.99 + 0.15x,r = 0.999, n = 3), and linear regions at mercury-coated silver-modified carbon SPEs in the range 8.9-36.4 ppm (regression equation; Y = 1.71 + 0.14x,r = 0.999, n = 3) and in the range 0.9-8.9 ppm (regression equation; Y = 1.34 + 0.17x,r = 0.980, n = 3), respectively. A particular advantage of using the mercury-modified SPE rather than the nickel-modified base card is that the well-defined electrochemistry of furan derivatives allow them to be individually distinguished. The half-wave potentials at the mercury SPE for 2-furaldehyde (E1/2 = -1.15 V vs. Ag/AgCl) and two possible interferents 2-acetyl-furan and 5-methyl-2-furaldehyde (E1/2 = -1.2 and -1.31 V vs. Ag/AgCl) are sufficiently well separated to allow the individual components to be resolved whereas at a nickel-modified SPE a combined signal is observed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140091710
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  • 8
    Electronic Resource
    Electronic Resource
    Proteome analysis of glycoforms: A review of strategies for the microcharacterisation of glycoproteins separated by two-dimensional polyacrylamide gel electrophoresis (1997)
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 452-460 
    Details
    ISSN: 0173-0835
    Keywords: Proteome ; Glycoprotein ; Two-dimensional polyacrylamide gel electrophoresis ; Post-translational modifications ; Oligosaccharides ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Preparative two-dimensional polyacrylamide electrophoresis (2-D PAGE) is a method of separation which for the first time allows protein isoforms to be readily purified for subsequent analysis. The profile of the 2-D separation of the protein complement (proteome) of eukaryotic cells and tissues typically contains obvious ‘trains’ of spots which differ in pI and/or apparent molecular mass. These are usually isoforms of the same protein and result from post-translational modifications. There is growing evidence that alterations to the glycosylation and/or phosphorylation of a protein can be correlated with developmental and pathological changes; these changes can be visualised on the 2-D separation. It is not clear, however, how these modifications alter the structural properties of the protein and affect their migration in this mode of separation. Strategies need to be developed to obtain a more detailed understanding of the reason for the appearance of isoforms as discrete spots on 2-D PAGE. Standard proteins, fetuin and ovalbumin, were used to monitor the effect of the removal of glycans and phosphates on the migration of the glycoproteins in the 2-D system. The isoforms were not simply explained by the presence or absence of a single modification. To further investigate the reasons for the different migration of the isoforms it is necessary to characterise the modifications in more detail. Unlike protein analysis, until recently the available methodology for the analysis of the glycans attached to proteins has not been sensitive enough to allow analysis of single spots in gels or blots resulting from 2-D electrophoresis. In this paper we review current and future strategies for characterisation of protein modifications using single spots from 2-D gels.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150180320
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  • 9
    Electronic Resource
    Electronic Resource
    A set of electrophoretic molecular markers for strain typing and population genetic studies of Histoplasma capsulatum (1997)
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 1047-1053 
    Details
    ISSN: 0173-0835
    Keywords: Microsatellites ; Fungi ; Molecular markers ; Epidemiology ; Histoplasma capsulatum ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A set of eleven biallelic and three multiallelic molecular markers have been developed to analyze populations of Histoplasma capsulatum. All markers are amplified by polymerase chain reaction (PCR) and can be readily scored using minimal amounts of template DNA. The 11 biallelic loci have polymorphic restriction endonuclease sites or small insertions or deletions which may be assessed by agarose gel electrophoresis. These markers are inherited in an unambiguous manner and are ideal for assessing structure and gene flow within US populations of H. capsulatum, but are monomorphic in non-US populations. Both length and sequence variation are present in the multiallelic loci, which can be scored by direct sequencing, polyacrylamide gel electrophoresis, or single-strand conformation polymorphism (SSCP): As they are hyper-variable, the multiallelic loci can be used to type isolates and to assess the level of genetic variation within populations. Preliminary results indicate that the three multiallelic markers presented are sufficient to distinguish isolates at the individual level and are polymorphic in both US and non-US populations. This collection of molecular markers will be a useful tool in population and epidemiology studies of H. capsulatum.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150180703
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of zwitterionic surfactants on the separation of proteins by capillary electrophoresis (1997)
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 732-735 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Proteins ; Zwitterionic surfactants ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The effect of zwitterionic surfactants on capillary electrophoretic separation of proteins was investigated using an uncoated silica capillary column and different buffers containing zwitterionic surfactants. The effects of N-alkyl-N,N-dimethyl ammonio-1-propane-sulfonates on the electrophoretic mobility of three different proteins, namely albumin, lysozyme and myoglobin, were examined. The addition of N-alkyl-N,N-dimethylammonio-1-propane sulfonate in phosphate saline buffer is important in minimizing protein-capillary wall interactions, and facilitated an efficient electrophoretic mobility of myoglobin and lysozyme. The separation efficiency of proteins also depends on the injection pressure for the control of migration time and the peak sharpness. The electrophoretic conditions were applied to evaluate the separation of lysozyme, myoglobin and albumin. The zwitterion surfactants can form a dynamic coating on the capillary surface, thereby reducing the number of adsorption sites to which proteins may adsorb.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150180512
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