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  • 1
    Electronic Resource
    Electronic Resource
    Mass spectrometry of derivatives of isomeric allenic fatty acids (1992)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 21 (1992), S. 267-270 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra have been obtained for isomeric C14 and C18 allenic fatty acids in the form of the methyl and picolinyl ester derivatives. When the allene moiety was in positions 3 to 9, the mass spectra of the methyl esters gave spectra with diagnostic ions that appeared to be formed by beta cleavage on the distal side of the molecule; otherwise hydrocarbon ions were dominant. With the picolinyl ester derivatives, distinctive fragmentations beta to the allene moiety on each side were observed for each isomer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200210508
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  • 2
    Electronic Resource
    Electronic Resource
    Morphological studies of blends containing liquid crystalline polymers with poly(ethylene terephthalate) (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 3063-3083 
    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: The investigation involved the structure-property behavior of extruded cast films prepared from blends of thermotropic liquid crystalline copolyesters with poly(ethylene terephthalate) (PET). Data were obtained which showed not only the temperature dependence of the moduli and stress-strain behavior but also the orientation effects that must be prevalent in order to explain the differences between the moduli measured parallel and perpendicular to the extrusion direction. Only at high liquid crystal polymer (LCP) composition is the modulus particularly increased. The modulus enhancement with lower LCP content and utilization of process variables are discussed with respect to the induced morphological textures and nature of the process equipment. Specifically, the process variable extruder gear pump speed did not enhance Young's modulus at the same LCP content as extensively as did the process variable of extruder screw speed.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070371101
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  • 3
    Electronic Resource
    Electronic Resource
    Mutation to increased resistance to phenol in Pseudomonas putida (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 20 (1978), S. 917-920 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260200612
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  • 4
    Electronic Resource
    Electronic Resource
    Sine transform based preconditioners for elliptic problems (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 4 (1997), S. 351-368 
    Details
    ISSN: 1070-5325
    Keywords: sine transform ; preconditioned conjugate gradient method ; elliptic partial differential equation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We consider applying the preconditioned conjugate gradient (PCG) method to solving linear systems Ax = b where the matrix A comes from the discretization of second-order elliptic operators with Dirichlet boundary conditions. Let (L + Σ)Σ-1(Lt + Σ) denote the block Cholesky factorization of A with lower block triangular matrix L and diagonal block matrix Σ. We propose a preconditioner M = (L^ + Σ^)Σ^-1(L^t + Σ^) with block diagonal matrix Σ^ and lower block triangular matrix L^. The diagonal blocks of Σ^ and the subdiagonal blocks of L^ are respectively the optimal sine transform approximations to the diagonal blocks of Σ and the subdiagonal blocks of L. We show that for two-dimensional domains, the construction cost of M and the cost for each iteration of the PCG algorithm are of order O(n2 log n). Furthermore, for rectangular regions, we show that the condition number of the preconditioned system M-1A is of order O(1). In contrast, the system preconditioned by the MILU and MINV methods are of order O(n). We will also show that M can be obtained from A by taking the optimal sine transform approximations of each sub-block of A. Thus, the construction of M is similar to that of Level-1 circulant preconditioners. Our numerical results on two-dimensional square and L-shaped domains show that our method converges faster than the MILU and MINV methods. Extension to higher-dimensional domains will also be discussed. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Real-time method for determining the colony-forming cell content of human hematopoietic cell cultures (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 55 (1997), S. 693-700 
    Details
    ISSN: 0006-3592
    Keywords: glucose ; lactate ; real-time determination ; hematopoietic cell culture ; colony-forming cells ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Glucose and lactate metabolic rates were evaluated for cultures of cord blood (CB) mononuclear cell (MNC), peripheral blood (PB) MNC, and PB CD34+ cell cultures carried out in spinner flasks and in T-flasks in both serum-containing and serum-free media. Specific glucose uptake rates (qgluc, in micromoles per cell per hour) and lactate generation rates (qlac) correlated with the percentage of colony-forming cells (CFC) present in the culture for a broad range of culture conditions. Specifically, the time of maximum CFC percentage in each culture coincided with the time of maximum qgluc and qlac in cultures with different seeding densities and cytokine combinations. A two-population model (Qlac = α[CFC] + β([TC] - [CFC]), where [TC] is total cell concentration; Qlac is volumetric lactate production rate in micromoles per milliliter per hour; α is qlac for an average CFC; and β is qlac for an average non-CFC) was developed to describe lactate production. The model described lactate production well for cultures carried out in both T-flasks and spinner flasks and inoculated with either PB or CB MNC or PB CD34+ cells. The values for α and β that were derived from the model varied with both the inoculum density and the cytokine combination. However, preliminary results indicate that cultures carried out under the same conditions from different samples with similar initial CD34+ cell content have similar values for β and β. These findings suggest that it should be possible to use lactate production data to predict the harvest time that corresponds to the maximum number of CFC in culture. The ability to harvest ex vivo hematopoietic cultures for transplantation when CFC are at a maximum has the potential to speed the rate at which immunocompromised patients recover. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 693-700, 1997.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Parallel superposition of small- and large-amplitude oscillations upon steady shear flow of polymer fluids (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 2303-2327 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The parallel superposition of small- and large-amplitude oscillations upon steady shear flow of elastic fluids has been considered. Theoretical results, obtained by numerical methods, are based upon the Leonov viscoelastic constitutive equation. Steady-state components, amplitude, and phase angle of oscillatory components of the shear stress, the first and second normal-stress differences as a function of shear rate, deformation amplitude, and frequency have been calculated. These oscillatory components include the first harmonic of the shear stresses and the first and second harmonic of the normal stresses. In the case of small-amplitude superposition, the effect of the steady shear flow upon frequency-dependent storage and loss moduli has been determined and compared with experimental data available in the literature for polymeric solutions and melts. In the case of large-amplitude superposition, the effect of oscillations upon the steady shear flow characteristics has been determined and compared with our experimental data for a polymeric melt. The experimental results for shear stress components have been found to be in good agreement with theoretical predictions, although there are some deviations for storage modulus at high shear rates. The deviations seem to be dependent on material. Moreover, the theory is unable to describe experimental data available for the first harmonic of normal stresses.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090261110
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  • 7
    Electronic Resource
    Electronic Resource
    Flow of thermoplastics in an annular die under parallel oscillations (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 1574-1584 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 sound wave extrusion system has been developed. This system includes a single screw extruder and an annular die having an internal surface oscillating in the sound frequency range. Oscillating shear flow has been imposed in the direction parallel to the main pressure flow. The die characteristics and average melt temperature at the exit from the die for several thermoplastics have been measured with and without imposition of oscillations. Modeling of parallel superposition of sound oscillations upon pressure flow has been performed using the Leonov viscoelastic constitutive equation. Three cases are considered: (i) the process is isothermal and the change in die pressure is only due to a nonlinear interaction of oscillatory and pressure flow; (ii) the process is nonisothermal and adiabatic, and pressure reduction is due to the nonlinear interaction and the dissipation of oscillatory energy leading to the temperature rise in polymer melts; (iii) the process is nonisothermal with heat transfer due to transient heat conduction and the dissipation of oscillatory energy. Pressure reduction occurs due to both nonlinear interaction and temperature rise. It is found that case (i) cannot explain the observed die pressure reduction, while case (ii) describes those data only at high flow rates. The theoretical results from case (iii) are found to be in qualitative agreement with experimental observations. Generally, the theoretical results of case (iii) are better than those of cases (i) and (ii).
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760302404
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  • 8
    Electronic Resource
    Electronic Resource
    Enzyme in der organischen Synthese: das Problem der molekularen Erkennung von Kohlenhydraten (Teil 1)Teil 2: Angew. Chem. 1995, 107, Nr. 5; Angew. Chem. Int. Ed. Engl. 1995, 34, Nr. 5. (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 107 (1995), S. 453-474 
    Details
    ISSN: 0044-8249
    Keywords: Enzyme ; Kohlenhydrate ; Organische Synthese ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die auf Zelloberflächen anzutreffenden Saccharide sind Informationsträger auf molekularer Ebene. Obwohl sich Säugetiere normalerweise auf die Verwendung von nur sieben oder acht Monosaccharidbausteinen beschränken, ist wegen der Multifunktionalität dieser Monomere der Aufbau einer schier unbegrenzten Zahl komplexer Strukturen möglich. So können beispielsweise mehrere Millionen topologisch unterschiedlicher Tetrasaccharide aus diesen wenigen Monosacchariden entstehen, wenn man die Art der Verzweigung, die Konfiguration des glycosidischen C-Atoms und Modifikationen der Hydroxy- und Aminogruppen in Betracht zieht. Oligosaccharide sind daher in der Lage, effizient die riesigen Datenmengen zu kodieren, die für biologische Erkennungsprozesse, von interzellulärer Kommunikation über Signalübertragung, Zelladhäsion, Infektion und Zelldifferenzierung bis hin zu Zellentwicklung und Metastase, benötigt werden. Trotz dieser zentralen Bedeutung ist die Entwicklung von pharmazeutischen Anwendungen dieser Substanzklasse verglichen mit der anderer Biomoleküle sehr langsam. Ein Grund dafür ist, daß Techniken zur Untersuchung komplexer Kohlenhydrate fehlen. So können Oligosaccharide weder für die Sequenzanalyse amplifiziert werden, noch gibt es eine Methode für ihre automatisierte Synthese. Darüber hinaus tragen die möglicherweise geringe Bioverfügbarkeit von Oligosacchariden und Schwierigkeiten bei ihrer Produktion in technischem Maßstab zweifellos nicht dazu bei, die Entwicklung zu beschleunigen. Die hier beschriebenen enzymatischen und chemoenzymatischen Methoden, besonders die unter Verwendung von Aldolasen und Glycosyl-Transferasen, erscheinen geeignet für die Synthese von Mono- und Oligosacchariden sowie verwandten Verbindungen. Es steht zu erwarten, daß weitere Fortschritte in der Glycobiologie neue Methoden eröffnen werden, mit denen die molekulare Erkennung bei Kohlenhydraten untersucht und bioaktive Saccharide und Saccharidmimetica zur gezielten Beeinflussung eben jener Erkennungsprozesse synthetisiert werden können.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19951070405
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  • 9
    Electronic Resource
    Electronic Resource
    Strain criterion in nonlinear creep and recovery in concentrated polymer solutions (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 1119-1148 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transient and steady-state rheological data are reported for several anionic polystyrene solutions in tritolylphosphate (1. 6 〈 cM/ρMc 〈 7). Here c is the concentration of the solution, M is the molecular weight, ρ the density of the undiluted polymer, and Mc the molecular weight between entanglements as determined from zero-shear viscosity. The polystyrene used had Mw = 410,000 and Mw/Mn 〈 1.06. Data are also given for solutions of polyisobutylene and poly(vinyl acetate) with larger Mw/Mn. The results give a critical strain γ′ ∝ c-1 such that linear viscoelastic behavior was obtained in a simple shear deformation with shear less than γ′. A simplified version of the constitutive equation of Bernstein, Kearsley, and Zapas is used with an empirical strain function F (γ) which contains γ′ as a parameter to discuss transient and steady-state behavior in terms of the distribution of relaxation (or retardation) times determined for linear viscoelastic responce. Features of the dependence of the steady-state viscosity ηk, recoverable compliance Rk, the first-normal stress function Nk(1) on shear rate k are discussed in terms of F (γ) and the distribution of relaxation times to conclude that the latter plays a dominant role in the behavior observed in the range of k usually studied. The results predict that the reduced functions ηk/η0, Rk/R0, and Nk(1)/N0(1) should depend on η0R0k, and that the functional form depends markedly on the distribution of relaxation times, at least in the range η0R0k 〈 102. Comparison with the mechanistic model of Doi and Edwards shows a similar F (γ) but substantial differences in the reduced functions caused by a very narrow distribution of relaxation times in the model.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220614
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  • 10
    Electronic Resource
    Electronic Resource
    Enzyme in der organischen Synthese: das Problem der molekularen Erkennung von Kohlenhydraten (Teil 2)Teil 1: Angew. Chem. 1995 107, 453-474; Angew. Chem. Int. Ed. Engl. 1955, 34, Nr. 4. Die Numerierung der Kapitel, der Literaturstellen, der Schemata und der Tabellen wird im zweiten Teil fortgeführt. (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 107 (1995), S. 569-593 
    Details
    ISSN: 0044-8249
    Keywords: Enzyme ; Kohlenhydrate ; Organische Synthese ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die molekulare Erkennung von Kohlenhydraten durch Proteine und Nucleinsäuren ist hochspezifisch, obwohl die Dissoziationskonstanten aufgrund der bei Kohlenhydraten fehlenden hydrophoben Gruppen in der Regel nur im millimolaren oder im oberen mikromolaren Bereich liegen. Die hohe Spezifität dieser schwachen Bindungen ist die Folge zahlreicher Wasserstoffbrückenbindungen und der Koordination von Metallatomen als Brücken zwischen Saccharid und Rezeptor. Zwar gibt es auch schwache hydrophobe Wechselwirkungen zwischen Zuckerbausteinen und Proteinen, doch sind hauptsächlich die durch den anomeren und den exo-anomeren Effekt festgelegte räumliche Struktur (die Torsionswinkel an der glycosidischen Bindung variieren im allgemeinen wenig) und die topographische Orientierung der Hydroxygruppen sowie der Einfluß von geladenen Gruppen am Erkennungsprozeß beteiligt. Für ein Studium der Beziehung zwischen der Struktur und der Funktion komplexer Kohlenhydrate ist daher eine gezielte Veränderung der dreidimensionalen Form und der funktionellen Gruppen erforderlich, was in der Regel durch die Synthese von Oligosacchariden aus veränderten Monosaccharidbausteinen erreicht wird. Die Verfügbarkeit unterschiedlich modifizierter Monosaccharide für die Oligosaccharidsynthese und die Ergebnisse aus Strukturuntersuchungen (z.B. NMR- und Kristallstrukturanalysen von Zucker-Protein-Komplexen) sind die Grundlage für ein Verständnis der Erkennung komplexer Oligosaccharide. Das Ziel ist die Entwicklung neuer Verbindungen, die nicht aus Saccharideinheiten bestehen und leicht zu synthetisieren sind, um sie als neue Liganden für Oligosaccharidrezeptoren oder als Enzyminhibitoren (z.B. für Glycosidasen und Glycosyl-Transferasen) einzusetzen. Wichtig ist dabei eine gute Bioverfügbarkeit dieser Verbindungen. Im ersten Teil dieses Aufsatzes haben wir einige Ansätze zur Synthese von Monosacchariden und ihren Analoga beschrieben. Hier wenden wir uns der enzymatischen und der chemoenzymatischen Synthese von Oligosacchariden und ihren Analoga zu, wobei wir ein besonderes Augenmerk auf die an der Erkennung von E-Selectin beteiligten Verbindungen legen. Weiterhin diskutieren wir Strategien zur Inhibierung von Glycosidasen und Glycosyl-Transferasen.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19951070505
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