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  • 1
    Electronic Resource
    Electronic Resource
    Mass transfer with chemical reaction in a threehyphen;phase foam-slurry reactor (1990)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 36 (1990), S. 117-125 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies on mass transfer coupled with chemical reaction were conducted in a gas-liquid-solid foam bed contactor under a variety of operating conditions in order to establish the controlling parameters for such a contacting system. Analytical equations were derived in order to predict the influence of solids dissolution on the specific rate of absorption in the stable foam stage of a three-phase foam-slurry reactor. Experimental investigations on the absorption of carbon dioxide in the presence of an aqueous foam-slurry containing calcium hydroxide particles were carried out in order to verify the theoretical model. Results indicate that the gas-liquid interfacial area and gas flow rate strongly affected the rate of mass transfer, while solids holdup affected mass transfer rates only moderately over the range of solids holdup studied. A comparison with conventional chemical reactor configurations (e.g., bubble column, CSTR) was made to demonstrate the gas-liquid-solid system, for which this novel reactor might be employed. Foam stability enhancement, due to the presence of solid particles, was not observed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690360114
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  • 2
    Electronic Resource
    Electronic Resource
    Cell death in bioreactors: A role for apoptosis (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 720-726 
    Details
    ISSN: 0006-3592
    Keywords: cell death ; apoptosis ; hybridoma cells ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The incidence of apoptotic and necrotic cell death was compared in CHO, SF9 insect cells and murine plasmacytoma (J558L) and hybridoma (TB/C3) cells during in vitro cultivation in batch cultures. Acridine orange staining and fluorescence microscopy enabled the visualization of a classic morphological feature of apoptotic cell, the presence of condensed and/or fragmented chromatin. DNA gel electrophoresis was employed to show an additional characteristic of the process, the endonuclease-mediated fragmentation of DNA into multiples of 180 base pairs. The levels of apoptosis at the end of batch cultures of plasmacytoma and hybridoma cell lines were found to be 60% and 90% of total dead cells, respectively. However, employing the above-mentioned techniques, the biochemical and morphological features of apoptosis were not found in CHO and SF9 insect cells. Some factors affecting the induction of apoptosis during the batch culture of the hybridoma and plasmacytoma cell lines were identified. The most effective inducer was found to be glutamine limitation, followed by (in order of importance) serum limitation, glucose limitation, and ammonia toxicity. Blockage of the cell cycle of the plasmacytoma and hybridoma cells using thymidine resulted in the induction of apoptosis. This has important implications for the development of cell culture processes that minimize cell division and thereby increase specific productivity. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260440608
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and chemo-physical properties of hydrogels (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 196 (1992), S. 49-61 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Hydrogele wurden aus methylmethacrylat (MMA) and N-Vinyl-2-pyrrolidon (NVP) mit 1,2,2-Trimethylolpropantrimethacrylat (TPTA) als Vernetzungsmittel hergestellt. Die Terplymerisation wurden mittels UV-strahlung (365 nm) initiiert, wobei kleine Mengen an Diethoxycetophenon (DEAP) als Photosensibilisator sowie Triethanolamin(TEA)als Beschleuniger und Verdünner verwendet wurden. Die Hydrogele wurden durch Messung des Wasserrückhaltevermögens, der Sauerstodiffusions- und permitionskoeffizienten, der mechanischen Eigenschaften und der Lichtdurchlässigkeit charakterisiert. Dabei zeigte sich, daß die Hydrogele bis zu 80 Gew.-% Wasser aufnehmen können, wobei mit steigendem Wassergtehalt deren mechanische Festigkeit drastisch sinkt. Der Ssuerstoffdiffusionskoeffizient der gequollenen Hydrogele beträgt 10-6 cm2s-1, der Sauerstoffpermeationskoeffizient 1013 cm2s-1Pa-1, und die Lichtdurchlässigkeit liegt im Bereich von 500 bis 700 nm bei über 90%.
    Notes: Hydrogels are synthesized from methyl methacrylate (MMA) and N-vinyl-2-pyrrolidone (NVP) with 1,1,1-trimethylol propane trimethacrylate (TPTA) as a crosslinking agent. It was polymerized under UV radiation (365nm) with a small amount of photosensitizer, diethoxy acetophenone (DEAP), acclerator and diluent, triethanol amine (TEA). The hydrogels were characterized by measuring the water retention, dissolved oxygen diffusivity and permeability, mechanical strength, and light transparency. The hydrogels can retain water up to 80 wt.-% and the mechanical strenght is weakened as the water content is increased in the gel. The dissolved oxygen diffusivity and permeability in the swelling hydrogels are determined to be 10-6 cm2/sec and 1013 cm2s-1 Pa-1, respectively. The light transparency is over 90% in the wave lenght ranging from 500 to 700 nm.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051960104
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  • 4
    Electronic Resource
    Electronic Resource
    Spinning and characterization of fibers from poly(2,6-dichloro-p-phenyleneterephthalamide): a study of constitutional isomerism and solid-state arrangements by comparison between simulation and experiment (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 475-510 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fibers of three constitutionally isomeric rigid-rod polymers, produced by polycondensation of 2,6-dichloro-p-phenylenediamine and terephthaloyl dichloride, were spun from nematic solutions and characterized by wide-angle X-ray diffraction (WAXD) measurements and mechanical tests. A post-spin heat treatment was employed to improve the low degrees of orientation and crystallinity that the untreated fibers showed. The dominating crystal structure of constitutionally ordered head-to-head/tail-to-tail fibers seems to be very similar to “Modification II” of the fibers from poly(p-phenyleneterephthalamide) (PPTA), but the fibers do not suffer a comparable structural transformation upon heat treatment. Influences of the constitutional regularity in the chains on the crystal structure, structural order and mechanical properties of the fibers could be observed. Both the observed crystal structure and the experimentally determined mechanical properties agree well with the results of detailed atomistic modeling predictions.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950209
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  • 5
    Electronic Resource
    Electronic Resource
    Conformational theory of large molecules: The rotational isomeric state model in macromolecular systems. By Wayne L. Mattice and Ulrich W. Suter, Wiley, New York, 1994, 449 pp. $54.95 (1996)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 1199-1200 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690420440
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  • 6
    Electronic Resource
    Electronic Resource
    Festlegung der Konformation von Lewis-Säure-Base-Komplexen: kristallographischer Beweis gleichzeitiger σ- und π-Koordination einer Carbonylgruppe an eine Lewis-Säure mit zweiwertigem BorDiese Arbeit wurde von der American Cancer Society, der Camille and Henry Dreyfus Foundation, der National Science Foundation (Young Investigator Award, mit Geldern von DuPont, Merck, Pfizer, Pharmacia & Upjohn, Procter & Gamble und Rohm & Haas) sowie der Research Corporation gefördert. Dank auch den Stiftern des Petroleum Research Fund, verwaltet von der American Chemical Society, für eine teilweise Unterstützung dieser Arbeit. Wir danken Deborah Gardner und Jeanne Owens für ihre Unterstützung bei der Aufnahme der HMQC-NMR-Daten. (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 109 (1997), S. 278-281 
    Details
    ISSN: 0044-8249
    Keywords: Bor ; Carbonylkomplexe ; Katalyse ; Lewis-Säuren ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19971090325
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  • 7
    Electronic Resource
    Electronic Resource
    Crystal structure of fibers from a novel rigid-rod aromatic polyamide containing a pyrimidine moiety (1991)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 2993-3004 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fibers of a novel rigid-rod polyamide containing a 1:1 ratio of phenylene:pyrimidine moieties have been produced and evaluated. The lyotropic liquid-crystalline behavior of the polymer and the spinnability of the nematic dope were established. The as-spun fibers exhibit low degrees of orientation and crystallinity. Heat treatment of the dry fibers resulted in crystallinities as high as 45% in coexistence with an amorphous phase component. Evaluation of the crystal structure by wide-angle X-ray diffraction suggests a pseudo-orthorhombic crystal cell with lattice dimensions (a; b; c) of (7,3 Å; 5,1 Å; 12,8 Å) and containing two repeating units per unit cell.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1991.021921215
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluation of a new absorbable lactomer® subcuticular staple (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 5 (1994), S. 221-226 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The most recent advance in skin stapling is the Auto Suture® SQS®-20 disposable stapler. It approximates and everts wound edges, placing one synthetic absorbable pin in the dermis each time the instrument handle is activated. Staple wound closure was accomplished four times faster than sutural closure of the dermis. Wounds with staple pin closure exhibit superior resistance to infection than wounds approximated by dermal sutures. Although sutures provide more immediate wound security, as measured by wound breaking strength, than dermal pins, the breaking strength of wounds subjected to either dermal pins or dermal sutures were not significantly different 14 days after wounding. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770050307
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  • 9
    Electronic Resource
    Electronic Resource
    Coupled solid phase extraction-supercritical fluid extraction-on-line gas chromatography of explosives from water (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 473-478 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction (SFE) ; Solid phase extraction (SPE) ; On-line analysis ; Gas Chromatography ; Explosives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for the quantitative extraction of nitrotoluenes (2,3-dinitrotoluene, 2,4-dinitrotoluene and trinitrotolugene) from water using a BakerbondTM phenyl sorbent. The average solid phase extraction recoveries for spiked standards ranged from 80 to 95 percent for reagent water and 52 to 95 percent from well and surface water in the low ppb and ppt levels. After the nitrotoluenes had been trapped on the solid sorbent they were quantitatively eluted using SFE. Adding toluene to the extraction cell increased the rate of extraction, but did not improve analyte recovery versus unmodified CO2. The extracts were analyzed off-line with GC-ECD using an internal standard. Extraction losses were due to analyte breakthrough, and not from poor SFE recoveries. This demonstrates that supercritical fluid extraction is a suitable elution technique for analytes trapped on solid phase extraction sorbents.Also, a method for the direct on-line coupling of SPE to GC, using SFE, has been developed and evaluated. Supercritical CO2 is ideal for directly coupling SPE to GC, since carbon dioxide is a gas under ambient conditions. One potential problem of on-line SPE-SFE-GC is the presence of residual water trapped on the active sites of the Bakerbond13 phenyl sorbent. This problem was dealt with by using a split interface previously described by Hawthorne. From the results of this study, the relative standard deviation of the on-line SPE-SFE-GC interface was determined to be between 4 and 10 percent. In addition, there was no significant difference in the precision of the method with or without the use of an internal standard. A calibration curve was also constructed (r2 = 0.995) from spiked controls, demonstrating that the method is quantitative.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160806
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of Semtex by supercritical fluid extraction and off-line GC-ECD and GC-MS (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 102-104 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction ; GC-MSD ; GC-ECD ; Semtex ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Researchers using electron capture for the detection of explosive vapors currently claim the ability to detect the presence of RDX in Semtex - a plastic explosive comprising hexahydro-1,3,5-trinitro-1,3,5-triazane (RDX) in a matrix of styrene-butadiene copolymer and hydrocarbon oil. The vapor pressure of RDX at room temperature is 0.006 ppb, and therefore well below the detection limit of electron capture detection (ECD). The positive response generated by ECD is, consequently, not from the presence of RDX, but from some other component.This paper describes the extraction and identification of several compounds in Semtex, along with the determination of which is responsible for the positive response of an ECD-based detector.From the results of supercritical fluid extraction and off-line gas chromatography combined with electron capture and mass spectrometric detection, it has been concluded that ethylene glycol dinitrate is the component responsible for the positive ECD response. This conclusion is based on the requirements necessary for ECD detection, i.e. electronegativity, and a sufficient vapor pressure. The other compounds present were eliminated as possible choices because they either can not be detected by an ECD or do not have sufficient vapor pressure under ambient conditions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150210
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