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  • 1
    Electronic Resource
    Electronic Resource
    High-density perfusion culture of insect cells with a BioSep ultrasonic filter (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 59 (1998), S. 351-359 
    Details
    ISSN: 0006-3592
    Keywords: bioreactor ; high density ; insect cells ; perfusion ; Sf9 ; ultrasonic filter ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The baculovirus/insect cell expression system has provided a vital tool to produce a high level of active proteins for many applications. We have developed a very high-density insect cell perfusion process with an ultrasonic filter as a cell retention device. The separation efficiency of the filter was studied under various operating conditions. A cell density of over 30 million cells/mL was achieved in a controlled perfusion bioreactor and cell viability remained greater than 90%. Sf9 cells from a high-density culture and a spinner culture were infected with two recombinant baculoviruses expressing genes for the production of human chitinase and monocyte-colony inhibition factor. The protein yield on a cell basis from infecting high-density Sf9 cells was the same as or higher than that from the spinner Sf9 culture. Virus production from the high-density culture was similar to that from the spinner culture. The results show that the ultrasonic filter did not affect insect cells' ability to support protein expression and virus production following infection with baculovirus. The potential applications of the high-density perfusion culture for large-scale protein expression from Sf9 cells are also highlighted. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:351-359, 1998.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Charge-remote fragmentation of bile acids derivatized with amino-sulphonic acids (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 235-240 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Negative-ion fast-atom bombardment mass spectra of free and conjugated bile acids are dominated by [M — H]- pseudomolecularions. Collision-induced dissociations of these pseudomolecular ions give charge-remote fragmentation patterns which are useful for structural identification. Taurine (2-aminoethanesulrtionic acid)-conjugated bile acids have a high cross-section for charge-remote fragmentation, and give the most informative and intense spectra among the naturally occurring bile acids. In the present study, collision-induced dissociation spectra of bile acids derivatized with different aliphatic and aromatic aminosulphonates, and with 2-amlnoethyl hydrogen sulphate have been compared. All show charge-remote fragmentation patterns. Determination of the intensities of the fragment ions shows that the highest sensitivity is usually obtained with aromatic aininosulpho-nate derivatives.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290070314
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  • 3
    Electronic Resource
    Electronic Resource
    The flammability of polyacrylonitrile and its copolymers IV. The flame retardant mechanism of ammonium polyphosphate (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 18 (1994), S. 307-312 
    Details
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Ammonium polyphosphate is shown to be an effective flame retardant for homopolymeric and selected fibre-forming copolymers of acrylonitrile. Compared with other phosphates and phosphorus-containing species, it significantly increases both limiting oxygen index and char levels. The mechanism of retardancy is shown to be both physical and chemical in character. When heated to 300°C, the polyphosphate melts and converts to polyphosphoric acid which acts as a physical barrier to surface polymer oxidation and promotes nucleophilic oligomerization of pendant, adjacent nitrile groups. A reduction in the activation energy of this first stage of acrylic polymer degradation suggests that the favoured decomposition route gives rise via oligomerization to char-promoting precursors. Char analyses indicate an empirical formula of C30H13N7P2, which compares favourably with that of a proposed phosphorylated, polynuclear, aromatic heterocyclic structure.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fam.810180506
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of Melting Behaviour on Upward Flame Spread of Thermoplastics (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 21 (1997), S. 1-6 
    Details
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The effect of melting behaviour on upward flame spread of thermoplastic materials when subjected to small ignition sources and considered to suffer no external flux was studied using large-scale tests. For moderate fire conditions the cone calorimeter was utilized, with the sample set in a vertical orientation to study the melting behaviour of the specimens. Under these conditions the results indicate that the melting behaviour significantly affects upward flame spread behaviour. A pool of the melt which formed at the base of the vertically oriented sample tested creates a pool fire which then controls the fire growth and flame spread. In contrast, it was found that some thermoplastic materials which have higher glass transition temperatures or undergo a special pyrolysis process such as depolymerization, intumescing or charring do not experience significant melting behaviour when exposed to the same thermal insult. As a result, they behave very differently in terms of upward flame spread. The study also indicates that the melting behaviour of thermoplastic materials is an important characteristic in fires which should be taken into account in the development of modelling, in particular for upward flame spread models. © 1997 by John Wiley & Sons, Ltd.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    The Structural Principles that Underlie the Higher Oxides of the Rare EarthsDedicated to Professor John D. Corbett on the Occasion of his 70th Birthday (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 465-472 
    Details
    ISSN: 0044-2313
    Keywords: Fluorite-related oxides ; rare earth oxides ; generalizations on structures ; modeling of structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Strukturelle Prinzipien bei den höheren Oxiden der Seltenen ErdenZur Aufklärung der strukturellen Prinzipien der Fluorit-verwandten homologen Serie höherer Selten-Erd-Oxide mit Anionen-Unterschuß war die Bestimmung einer hinreichenden Anzahl ihrer Strukturen vonnöten. Neuere Strukturverfeinerungen an fünf weiteren Mitgliedern dieser Serie erlauben eine Reihe von allgemeingültigen Aussagen über ihr Kristallisationsverhalten. Über diese generellen Prinzipien wird berichtet. Darüber hinaus wird, auf der Grundlage des Fluorittyps, ein phänomenologisches Prinzip vorgestellt, das erstens alle bekannten und möglichen Phasen in diesem fluoritverwandten Systemen durch eine Formel miteinander verknüpft, zweitens alle bekannten Strukturen richtig wiedergibt und drittens uns in die Lage versetzt, Modelle für alle noch unbekannten Strukturen oder Polymorphe dieser Serie abzuleiten. Benötigt werden hierzu lediglich Elektronenbeugungsaufnahmen, die die Bestimmung der Überstrukturzelle zulassen sowie eine Vorstellung über die Zusammensetzung.
    Notes: The structural principle that accounts for the aniondeficient, fluorite-related homologous series of higher rare earth oxides has awaited the determination of a sufficient number of their structures to test hypotheses. Recent structure refinement of five additional members has permitted extraction of a number of generalizations concerning their crystallization behavior. These general principles are outlined. Furthermore, based on the fluorite structure itself, a phenomenological structural principle is outlined that (1) unifies all known and possible phases in these fluorite-related systems under one generic formula, (2) models all known structures correctly and (3) enables modeling of any unknown structure or polymorph in the series. All that is required are electron diffraction patterns adequate to determine the supercell and a knowledge of its composition.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220314
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  • 6
    Electronic Resource
    Electronic Resource
    Chemical modification in mass spectrometry IV - 2-alkenyl-4,4-dimethyloxazolines as derivatives for the double bond location of long-chain olefinic acids (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 33-44 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Long-chain unsaturated fatty acids (UFA) can easily be converted on a microgram scale to the corresponding 2-alkenyl-4,4-dimethyloxazolines by condensation with 2-amino-2-methylpropanol (AMP). These modified molecules with a ‘hidden’ carboxyl group have been proved to be a class of useful derivatives for gas chromatography/mass spectrometry (GC/MS) of UFA mixtures. While possessing very good GC characteristics, the title compounds show regular, well-recognizable diagnostic ion peaks of the double bond position in the chain. Detailed description of the method as well as electron impact (E1) mass spectra of derivatives resulting from mono-, di and polyenoic (maximally containing six double bonds) acids are presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150106
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  • 7
    Electronic Resource
    Electronic Resource
    In situ studies of epitaxial silicon growth by gas source molecular beam epitaxy (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 7 (1997), S. 215-224 
    Details
    ISSN: 1057-9257
    Keywords: silicon ; epitaxy ; kinetics ; dynamics ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The value of in situ monitoring to study growth dynamics and surface reaction kinetics in a gas source molecular beam epitaxy process is illustrated with reference to the growth of Si films on Si(001) substrates using a beam of disilane (Si2H6). By using a combination of reflection high-energy electron diffraction (RHEED) and reflection anisotropy spectroscopy (RAS), we show first how morphological (long-range order) and local electronic structure effects can be separated in the evaluation of growth dynamics. This involves the measurement of step density changes by RHEED concomitantly with the variation in domain coverage on the Si(001) (2×1)+(1×2) reconstructed surface by RAS. This approach is then extended to investigate the kinetics of hydrogen desorption, which is the rate-limiting step in Si growth from Si2H6. It is shown that over a significant temperature range, zeroth-order kinetics are obeyed and this is explained on the basis of a step-mediated desorption process. Finally we show how this influences the growth rate on substrates of differing degrees of vicinality. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Matrix-size interactions in epoxy-glass fibers composites in relation to mechanical relaxations and effects of thermal aging (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 55 (1995), S. 1771-1777 
    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: A study was carried out to examine the effect of removing the size from the surface of glass fibers in order to determine its role with respect to thermoxidative aging. Dynamic mechanical relaxation data have revealed that mechanical losses were always greater than the calculated upper bound values. The effects of removing the size from the surface glass fibers for epoxy matrix composites were found to be completely different when a fluoroligomer was used to modify the resin. Contrary to the case of the conventional epoxy resin, the characteristics of the composites containing fluoroligomer-modified resin were found to be insensitive to the removal of the size from the glass fibers surface. The presence of the size on the surface of the fibers provides an interlayer that degrades through the formation of more lightly crosslinked products than the matrix, thereby providing a large increase in dynamic mechanical losses after thermal aging. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070551307
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  • 9
    Electronic Resource
    Electronic Resource
    Mechanisms of carbon dioxide laser stereolithography in epoxy-based materials (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 491-500 
    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: We present in this article the use of infrared laser radiation to achieve localized curing in thermosensitive epoxy resin compounds. In stereolithography, the objective is to cure a localized region in a material by precisely confining the laser energy to the area that is to be cured. Industry already uses ultraviolet laser radiation at 352 nm to fabricate three-dimensional structures. Via infrared laser curing, we demonstrate the viability of a completely thermal localized curing process. In our experiment, we have focused the beam from a carbon dioxide (CO2) laser onto a sample composed of epoxy resin, diethylene triamine, and silica powder. Such resins typically cure, or solidify, when heated to moderately high temperatures, and our results show that we can confine the heating of the material, and, therefore, its curing in all three dimensions. We present a physical and a chemical model to describe the process and measure the curing rate as a function of temperature. In order to model the flow of heat in our sample as a result of infrared laser irradiation, we solved the time-dependent heat equation in cylindrical coordinates using the Crank-Nicholson finite-difference method. The results allow us to predict the curing behavior of the sample as a function of laser irradiation conditions, and we find good agreement with our preliminary experimental observations. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Optical activity based on macromolecular asymmetryPart XXVI of Haloaldehyde Polymers; Part XXV : E.G. Brame, A. M. Raevsky, G. K. Semin, G. D. Jaycox, and O. Vogl, Polymer Bulletin 10(11/12), 521 (1983) (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 13 (1985), S. 1-12 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Optically active isotactic polychloral was prepared in which the optical activity comes exclusively from molecular asymmetry (i.e., helical conformation). Molecular asymmetry requires a high conformational energy barrier for the polymer backbone, and an asymmetric initiator to induce a predominance of one helical screw-sense. Polychloral meets the criteria. Asymmetric initiators used to obtain optically active polychloral include tetramethyl ammonium (+)- or (-)-0-acetylmandelate, tetramethylammonium (+)- or (-)-0-methylmandelate, the lithiumalkoxides of methyl (+)- or (-)-mandelate, lithium cholesten-3β-oxide, lithium cholestan-3β-oxide, and lithium (+)- or (-)-2-octanoxide. Using the above initiators at 0.5 mol %, a maximum specific rotation of [α] D25 = 5000 was obtained for polychloral. Errors in specific rotation were typically ±7%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020131985102
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