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  • 1
    Electronic Resource
    Electronic Resource
    The induction of cytochrome P-450 in the alkane-utilizing yeast Lodderomyces elongisporus: Alterations in the microsomal membrane fraction (1984)
    Springer
    Applied microbiology and biotechnology 19 (1984), S. 29-35 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The adaptation of Lodderomyces elongisporus cells to n-alkane utilization was found to be connected with several alterations in the enzyme pattern of the whole cell and the microsomal fraction in particular. A strong induction was found for the microsomal localized cytochrome P-450 alkane hydroxylase system and other enzymes which are directly involved in the terminal degradation pathway of n-alkanes (long-chain alcohol and aldehyde dehydrogenases, catalase). The decrease of the pO2 in the medium enhances the concentration of the constituents of the alkane hydroxylase system as well as that of several other haemoproteins (catalase, cytochrome oxidase), while the long-chain alcohol and aldehyde dehydrogenase enzymes are probably unaffected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00252813
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  • 2
    Electronic Resource
    Electronic Resource
    Untersuchungen über spezifische Organe niederer Sinne bei rhabdocoelen Turbellarien (1936)
    Springer
    Journal of comparative physiology 23 (1936), S. 253-292 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00344199
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  • 3
    Electronic Resource
    Electronic Resource
    Substrate specificity and stereoselectivity of fatty alcohol oxidase from the yeast Candida maltosa (1992)
    Springer
    Applied microbiology and biotechnology 37 (1992), S. 66-73 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary In Candida maltosa and other alkene-utilizing yeasts a membrane-bound fatty alcohol oxidase (FAOD) is induced by growth on n-alkenes. The oxidation of 1-alkanols to the corresponding aldehydes is accompanied by the stoichiometric consumption of 1 mol O2 and formation of 1 mol hydrogen peroxide (H2O2). The FAOD of C. maltosa shows a broad substrate specificity. It catalyses the oxidation of 1-alkanols (C4 to C22), with a maximal activity of 1.85 gmmol H2O2/ min × mg protein for 1-octanol, as well as the transformation of 2-alkanols (C8 to C16) to ketones. Other compounds as α,ω-alkenediols, ω-hydroxypalmitic acid, phenylalkanols and terpene alcohols are substrates for the enzyme, although mostly with decreased activities. The oxidation of the racemic 2-alkanols by the FAOD proceeds with very high stereoselectivity for the R(−)-enatiomers only, leaving the S(+)-2-alkanol untouched.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174205
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  • 4
    Electronic Resource
    Electronic Resource
    A hypothesis on the abnormal seasonality of schizophrenic births (1990)
    Springer
    European archives of psychiatry and clinical neuroscience 239 (1990), S. 331-334 
    Details
    ISSN: 1433-8491
    Keywords: Seasonal variation ; Pregnancy duration ; Excess risk of schizophrenic births
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The hypothesis is proposed that the abnormal seasonality of schizophrenic births is partly a consequence of seasonal variation of conception and of an associated seasonal variation of risk of premature delivery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01735060
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  • 5
    Electronic Resource
    Electronic Resource
    Locally adaptive hazard smoothing (1990)
    Springer
    Probability theory and related fields 85 (1990), S. 523-538 
    Details
    ISSN: 1432-2064
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We consider nonparametric estimation of hazard functions and their derivatives under random censorship, based on kernel smoothing of the Nelson (1972) estimator. One critically important ingredient for smoothing methods is the choice of an appropriate bandwidth. Since local variance of these estimates depends on the point where the hazard function is estimated and the bandwidth determines the trade-off between local variance and local bias, data-based local bandwidth choice is proposed. A general principle for obtaining asymptotically efficient data-based local bandwiths, is obtained by means of weak convergence of a local bandwidth process to a Gaussian limit process. Several specific asymptotically efficient bandwidth estimators are discussed. We propose in particular an, asymptotically efficient method derived from direct pilot estimators of the hazard function and of the local mean squared error. This bandwidth choice method has practical advantages and is also of interest in the uncensored case as well as for density estimation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01203169
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanical shear degradation of polymers in solution by turbulent flow, 3Teil 2: cf.25.. The influence of chemical constitution and thermodynamic quality of the solvent on shear degradation (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 3545-3560 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mechanical shear degradation of polyisobutylene, polystyrene, poly(vinyl chloride), poly(methyl methacrylate), poly(decyl methacrylate), poly(methyl acrylate), and 1,4-polybutadiene in dilute solutions of tetrahydrofuran (THF) are studied under turbulent flow conditions through a capillary, in order to study the effect of the chemical constitution on shear degradation. In addition the influence of solvent quality on shear degradation is investigated. The changes of the molecular weight distribution curves were followed by gel permeation chromatography (GPC), in order to determine the degradation constants ki for the corresponding molecular weight distribution fractions M̄i. GPC calibration via the concept of universal calibration, Mark-Houwink relations for polyisobutylene, poly(methyl methacrylate), poly(methyl acrylate), 1,4-polybutadiene, and poly(dimethylsiloxane) in THF as solvent had to be established for this purpose. Substantial differences in the rate constants ki were observed as a function of M̄i, whereas a master curve resulted for all polymers except 1,4-polybutadiene when ki was plotted against the number of main chain carbon atoms n̄i for each molecular weight M̄i. From this the shear degradation of C—C single bond polymers can be represented by ki = C · n̄ia, C being independent of the chemical nature of the C—C single bond polymer, and a varying from 1,7 to 2,6. This means that in addition to the shape of the deformed macromolecule to be degraded not only its hydrodynamic volume (in rest) but also its chain length plays an important role. As to the influence of solvent quality, the degradation constants were found to increase with decreasing solvating power of the solvent. Mechanical shear degradation of the type discussed here takes place in drag reduction by polymers.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021821217
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  • 7
    Electronic Resource
    Electronic Resource
    Mechanischer Scherabbau von Polymeren in Lösung mittels turbulenter Strömung, 1. Kinetik, Molekulargewichtsabhängigkeit und Frage des Bruchmechanismus (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 513-528 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanical shear degradation of poly(decyl methacrylate) with weight average molecular weights 1,0·106 ≤ M̄w ≤ 1,7·106, and molecular polydispersity ratio M̄w/M̄n = 5 in dilute solutions is studied in turbulent flow as a function of molecular weight using a special apparatus consisting of two vessels connected by a capillary. Shear stress and shear rate remained constant during degradation. The rate of degradation was followed up by molecular weight distribution curves using gel permeation chromatography and described by -dci/dt = ki·cn, i being a high molecular weight species of the distribution. The reaction was found to be of the first order (n = 1) independent of solvent and of capillary length. Rate constants ki in the molecular weight range from 3,2·106 to 13,5·106 proved to be proportional to the hydrodynamic volume of the polymer molecules expressed in terms of the product of intrinsic viscosity and molecular weight [η]i·Mi. This corresponds to a linear relationship between ki and Mi1,75. Additional experiments show that this type of dependence on molecular weight holds only for turbulent flow; in laminar flow the result of the literature could be confirmed that there is a linear relation between ki and Mi1. Both results are independent of capillary length. As to the mechanism of breakage in turbulent flow it seems that in one step each macromolecule is broken simultaneously into several smaller parts.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820219
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  • 8
    Electronic Resource
    Electronic Resource
    Mechanischer Scherabbau von Polymeren in Lösung mittels turbulenter Strömung, 2Teil 1: cf.12.. Die Abhängigkeit der Abbaugeschwindigkeit von der Polymergesamtkonzentration in guten Lösungsmitteln (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 529-547 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mechanical shear degradation of poly(decyl methacrylate), (viscosity average molecular weight in tetrahydrofuran M̄η = 1,3·106, M̄w/M̄n = 5) in the thermodynamically good solvent tetrahydrofuran has been studied in turbulent flow through a capillary as a function of polymer concentration in the range from 0,22 to 8,9 g/100 cm3. Due to turbulent flow conditions the shear stress, shear rate and shear energy proved to be the same for all concentrations and remained constant during degradation, giving a general insight into mechanism of degradation. The rate of degradation has been followed using molecular weight distribution curves obtained by gel permeation chromatography. The reaction was found to be of first order. Rate constants determined for molecular weights from 3,2-9,5·106 decreased with increasing concentration following a law of the type ki = (K + b·c)-1, K and b being constants for each molecular weight. Hydrodynamic volumes of polymer molecules have been calculated according to models of Rudin as function of molecular weight and concentration. It can be shown that rate constants of degradation and calculated hydrodynamic volumes are proportional for the whole range of molecular weight and concentrations up to 3,6 g/100 cm3. There is also a rather good proportionality between these rate constants and the volumes of polymer coils predicted by de Gennes. This result is an additional confirmation of the concept that hydrodynamic volume governs shear degradation of polymer solutions. Additional experiments show that this type of concentration dependence is also to be found for other polymers in other solvents.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820220
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  • 9
    Electronic Resource
    Electronic Resource
    Bicyclen. V. Untersuchungen über Alkohole und Ester aus der Bicyclo-(2,2,1)-heptan-Reihe (1966)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 34 (1966), S. 283-297 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In der vorliegenden Arbeit wurden 1-[Bicyclo-(2,2,1)-hept-5-enyl-(2)]-alkanole sowie 1-[Bicyclo-(2,2,1)-heptyl-(2)]-alkanole dargestellt und die nach verschiedenen Methoden gewonnenen Verbindungen auf ihre endo-exo-Isomerenzusammensetzung untersucht. Zur Darstellung eignen sich Umsetzungen von bicyclischen Aldehyden nach Grignard sowie die Reduktion von Ketonen und Estern. Die Reduktion von Aldehyden führt zu 2,5-Methylen-1,2,5,6-tetrahydrobenzylalkohol bzw. 2,5-Methylen-hexahydrobenzylalkohol.Die Veresterung obiger Alkohole mit Chloriden und Anhydriden von Mono- und Dicarbonsäuren liefert Verbindungen, die pharmakologische Wirkung erwarten lassen.Versuche zur Ermittlung einer eventuellen relativen Reaktionsgeschwindigkeit endo-exo-isomerer Alkohole wurden durchgeführt.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19660340507
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  • 10
    Electronic Resource
    Electronic Resource
    Zum abbau von polymerlösungen durch kapillarscherung. Einfluß der kapillarlänge und strömungsform auf den abbau (1977)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 57 (1977), S. 99-109 
    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: The dependence of shear degradation of polymer solutions on capillary length at constant shear stress is investigated with solutions of poly(isobutylene) (Mvis=6,1 · 106) in toluene. We examined concentrations of 0.1, 0.25, 1 and 4% and found the degradation to increase with capillary length. In 0,1% solution we found a decreased efficiency of degradation, due to a change in the structure of solution.Flow instabilities, which appear above a critical shear rate D in polymer solutions and pretend a loss in viscosity, are not caused by shear degradation. This result supports our interpretation of unstable flow of polymer solutions as slip flow (spurt).
    Notes: Der Einfluß der Kapillarlänge auf den Abbau von Polymerlösungen bei konstanter Schubspannung wird an Lösungen von Polyisobutylen (Mvis=6,1 · 106) in Toluol untersucht. Bei allen untersuchten Konzentrationen (0,1, 0,25, 1 und 4%) nimmt der Abbau mit steigender Kapillarlänge zu. Bei der 0,1proz. Lösung findet sich eine verringerte Effektivität des Abbaus, was auf eine Äderung der Lösungsstruktur zurückzuführen ist. Das oberhalb einer kritischen Scherrate D bei Polymerlösungen zu beobachtende instabile Fließen (scheinbare Viskositätsabnahme) ist nicht ursächlich auf Scherabbau zurückzuführen. Dieses Ergebnis ist eine indirekte Stütze für die Deutung dieser Fließerscheinung als Gleitfließen (spurt).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1977.050570108
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