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  • 1
    Electronic Resource
    Electronic Resource
    The association behavior of β-lactamases in polyethylene glycol solution (1988)
    New York : Wiley-Blackwell
    Biopolymers 27 (1988), S. 865-881 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The β-lactamases (EC 3.5.2.6) from Bacillus licheniformis 749/C, Enterobacter cloacae P99, and TEM plasmid RP4 are studied in 10-14% (w/v) polyethyleneglycol (PEG) 8000 solutions at pH 6.5 by x-ray scattering and in 18% PEG by equilibrium sedimentation. Although all three enzymes crystallize with twofold crystal symmetry from PEG 8000, it is not possible in this study to prove that dimerization occurs; however, both techniques give evidence for association above 1% (w/v) protein concentration. For the B. lichen., P99, and TEM enzymes, a dimerization of at most 0, 5, and 10% (v/v), respectively, account for the variation of radii of gyration Rg with concentration, after accounting for the effects of nonideality. Apparent Rg were 3-5% smaller in PEG solution than in PEG-free solution. Enhanced ordering of the molecules in PEG solution or the presence of a PEG-depleted hydration shell around the enzymes can account for the observation of reduced Rg values. Accordingly, values of the partial specific volume (defined at constant chemical potential of PEG) indicate considerable PEG exclusion and are consistent with the ability of high Mr PEGs to induce crystallization of these enzymes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360270512
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  • 2
    Electronic Resource
    Electronic Resource
    Syntheses of O-Methylasparvenone-Derived Serotonin-Receptor Antagonists (1998)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 81 (1998), S. 525-538 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Based on O-methylasparvenone (1), a N-free 5HT2C antagonist with moderate affinity (pKi = 6.7), derivatives bearing dimethylamino (7), (dimethylamino)methyl (17, 18, 21, and 22), and aminomethyl substituents (26) in place of the benzylic OH group of 1 as well as pyrrolidine- (33) and piperidine-fused derivatives (29, 43, and 45) were synthesized. In contrast to the lead structure 1, these new ligands were active in vivo in the rat. The tricycles 33 and 45 display high affinities for the 5HT2C receptor (pKi = 8).
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19980810306
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  • 3
    Electronic Resource
    Electronic Resource
    Über Isopren und Kautschuk. 24. Mitteilung. Über die Reduktion des Kautschuks mit Jodwasserstoffsäure (1930)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 13 (1930), S. 1321-1324 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19300130614
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of isotopically labelled monomers and polymers of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acidDedicated to Prof. Dr. W. Heitz on the occasion of his 60th birthday (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 649-663 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Synthesis and characterization of 4-acetoxybenzoic acid and 6-acetoxy-2-naphthoic acid, labelled with deuterium in the rings and with carbon-13 and oxygen-17 in the carboxyl-positions, and of the corresponding homo- and copolyesters, are described. Kinetic studies of hightemperature deuteration were performed on 6-hydroxy-2-naphthoic acid. Mass spectrometry provides information about the degree of labelling with 2H, 13C and 17O. Composition and molecular weight of isotopically labelled polymers were monitored by 1H NMR after digestion in basic methanol. The thermal behavior was investigated by differential scanning calorimetry and thermogravimetry.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940224
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  • 5
    Electronic Resource
    Electronic Resource
    Dispersion analysis in homogeneous lakes (1980)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 15 (1980), S. 1627-1642 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper is devoted to a comparison of the relative accuracy of two-dimensional vs. three-dimensional finite element representations of contaminant dispersion in shallow lakes. Formulations of both types are developed, followed by numerical calculations of a hypothetical lake. The results indicate that for typical lakes a two-dimensional dispersion analysis can be employed in the absence of a significant advective contribution. With significant advection the two-dimensional approach is not sufficiently accurate. A two-dimensional dispersion analysis requires approximately the same computational resources as a three-dimensional circulation analysis.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620151106
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  • 6
    Electronic Resource
    Electronic Resource
    Reaction of excited oxygen species with polymer films (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 2477-2482 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Reaktion von atomarem und von Singulett-Sauerstoff mit Filmen aus verschiedenen Polymeren wurde untersucht an Polyvinylchlorid, Polyacrylnitril, Polystyrol, Nylon 66 und Polyäthylenterephthalat. Atomarer Sauerstoff reagierte leicht mit den genannten Polymeren. Die Reaktion beschränkte sich auf die Oberfläche, was dazu führte, daß die Polymeren hydrophiler wurden. Der Kontaktwinkel von Wasser mit Filmen von Polyvinylchlorid und Polystyrol zeigt nach mehrstündiger Einwirkung von Singulett-Sauerstoff keine Änderung.
    Notes: The reaction of atomic oxygen and singlet oxygen molecules with films from various polymeric substrates was studied. The polymers used were poly(vinyl chloride), polyacrylonitrile, polystyrene, nylon 66, and poly(ethylene terephthalate). Atomic oxygen reacted readily with all of these polymers. The reaction was confined to the surface layers which results in the polymer films becoming more hydrophilic. No change was observed in the contact angle of water with films of poly(vinyl chloride) and polystyrene after they had been exposed to singlet oxygen molecules for several hours.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021750820
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  • 7
    Electronic Resource
    Electronic Resource
    Heterogeneous nucleation and growth of spherulites from a polycaprolactone (poly(1-oxy-6-oxohexamethylene)) melt (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 2483-2488 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird über den Beginn einer Untersuchung zur Kristallisationskinetik von Polycaprolacton (Poly(1-oxy-6-oxohexamethylene) (1)) berichtet. Die primäre Keimbildung und das primäre Sphärolith-Wachstum aus der Polymerschmelze werden bei hinreichend hohen Temperaturen verfolgt, wodurch sichergestellt ist, daß das Wachstum der Kristallite durch Keimbildung bestimmt ist. Die kinetischen Daten werden weitgehend mit Hilfe des Avrami-Modells interpretiert, welches sich gut auf die Kristallisation von 1 anwenden ließ.
    Notes: A kinetic crystallization study of polycaprolactone (poly(1-oxy-6-oxohexamethylene) (1)) has been initiated to investigate the primary nucleation and primary spherulitic growth from a polymer melt at temperatures that are high enough to insure nucleation-limited crystallite growth. The analysis of the kinetic data is largely made on the basis of an Avrami model which proved to be well suited for the interpretation of the crystallization of 1.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021750821
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  • 8
    Electronic Resource
    Electronic Resource
    Cubic spline boundary elements (1981)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 17 (1981), S. 543-556 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The boundary integral method is formulated and applied using cubic spline interpolation along the boundary for both the geometry and the primary variables. The cubic spline interpolation has continuous first and second derivatives between elements, thus allowing the accurate calculation of derivative dependent functions (on the boundary) such as velocity in potential flow. The spline functions also smooth the geometry and can represent curved sections with fewer nodes.The results of numerical experiments indicate that the accuracy of the boundary integral equation method is improved for a given number of elements by using cubic spline interpolation. It is, however, necessary to use numerical quadrature. The quadrature slows calculation and/or degrades the accuracy. The numerical experiments indicate that most problems run faster for a given accuracy using linear interpolation. There seems to be a class of problems, however, which requires higher order interpolation and/or continuous derivatives for which the cubic spline interpolation works much better than linear interpolation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620170405
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  • 9
    Electronic Resource
    Electronic Resource
    Determination of the enantiomeric purity of scopolamine isolated from plant extract using achiral/chiral coupled column chromatography (1991)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 5 (1991), S. 3-7 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The optical purity of scopolamine derived from Datura sanguinea was determined using coupled column chromatography. A C18 column was used to separate scopolamine from the additional alkaloids and other biological material present in the vegetal extract. The C18 column was coupled through a six-port switching valve to two β-cyclodextrin columns in series which were used to resolve the scopolamine enantiomers. A single acetylated β-cyclodextrin column gives equivalent results to the native cyclodextrin columns because of slightly higher enantioselectivity for scopolamine. A multistep extraction procedure is used to isolate scopolamine from the vegetal material. 4-6% of the scopolamine in the final extract was found to be the d enantiomer. Sample extracts as well as commercial scopolamine hydrobromide were treated under various conditions commonly encountered during typical commercial extraction procedures and analyzed in order to determine if the d enantiomer was present in the original material or if it was produced during the extraction process and, if so, determine which step and conditions contribute to acemization. Both the salt and the extract were found to be susceptible to racemization under basic conditions (≥pH 9) although the extract appeared to be more susceptible than the salt. Tropic acid formed from the hydrolysis of scopolamine seemed to be completely racemized even though the remaining scopolamine was only partially racemized. Within experimental error, no d enantiomer was found in the original fresh plant material.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130050103
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  • 10
    Electronic Resource
    Electronic Resource
    The glass temperature of asphalt (1963)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 7 (1963), S. S45 
    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
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1963.070070635
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