Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Hyaluronic Acid-(Hydroxypropyl)cellulose Blends: A Solution and Solid State Study (1995)
    s.l. : American Chemical Society
    Macromolecules 28 (1995), S. 3531-3539 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00114a006
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Glycolipid self-assembly: micellar structure (1991)
    s.l. : American Chemical Society
    Langmuir 7 (1991), S. 2580-2585 
    Details
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/la00059a031
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Conventional and Microwave-Hydrothermal Synthesis of TiO2 Nanopowders (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of the American Ceramic Society 88 (2005), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The objective of this study was to compare the conventional and microwave hydrothermal treatment of TiOCl2 solutions. Colloidal titania suspensions were prepared by forced hydrolysis at 195°C for different times ranging from 1 to 32 h for the conventional synthesis and from 5 min to 1 h for the microwave ones. The effect of the microwave technology on both the synthesis conditions and titania nanoparticles properties has been evaluated. Particles morphology and crystallinity were studied by using transmission electron microscopy and X-ray diffraction. The thermal and chemical stability of the obtained powders were determined by TG/DTA analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00474.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Enzymatic hydrolysis of cellulosic materials: A kinetic study (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 26 (1984), S. 1233-1238 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A kinetic study of the enzymatic hydrolysis of two celluloses with different structural features was performed at various temperatures (26-50°C). The enzymatic system consisted of three types of enzymes: E1 - β-1,4-glucan glucanohydrolase; E2 - β-1,4-glucan cellobiohydrolase; and E3 - β-glucosidase. A mathematical model for the mechanism of the hydrolysis of cellulosic materials catalyzed by a multienzymatic system was checked and a good rationalization of the experimental results was achieved. Uncompetitive and competitive glucose inhibition on E1 and E2, respectively, appeared to occur for both substrates. Inhibition by cellobiose was checked at 34°C on one substrate. The Vmax, Km, and glucose inhibition constants were optimized and their dependence on temperature determined.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260261013
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Hydrolysis of inulin: A kinetic study of the reaction catalyzed by an inulinase from Aspergillus ficuum (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 37 (1991), S. 575-579 
    Details
    ISSN: 0006-3592
    Keywords: inulin ; inulinase ; fructose ; enzymic hydrolysis ; kinetics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A kinetic study of the hydrolysis of inulin was performed by using as catalyst a commercial inulinase from Aspergillus ficuum. The reaction was studied carrying out initial rate as well as time course measurements. Both inulinase and invertase activities of the enzyme were taken into account, and the corresponding kinetic parameters were determined in the temperature range 30-50°C. The activation energies of the turnover constant for inulinase and invertase activities were found to be similar (56-57 kJ · mol-1). The ratio S/I of invertase to inulinase activity was 1.6 regardless of temperature. The thermal degradation of the enzyme was also investigated up to 70°C, and an activation energy of 350-370 kJ · mol-1 was evaluated.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260370612
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Evaluation of steam explosion as pretreatment in agar extraction fromGracilaria dura (C. Agardh) J. Agardh (Gracilariaceae, Rhodophyta) (1993)
    Springer
    Journal of applied phycology 5 (1993), S. 417-424 
    Details
    ISSN: 1573-5176
    Keywords: steam explosion ; agar ; Gracilaria dura ; Gracilariaceae ; Rhodophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Steam explosion was investigated as a pretreatment step in the isolation of agar from the macroalgaGracilaria dura. As compared to conventional procedures, the yield of agar obtained using this method on alkali (Na2CO3) conditioned algal material was higher. Extractions performed first at 95 °C and then at 121 °C showed that the major fraction of the agar was extracted at 95 °C, independently of the pretreatment. The efficiency of sulphate hydrolysis during steam explosion ofG. dura previously conditioned in Na2CO3, was similar to that of a NaOH based alkali pretreatment. Except for a lower nitrogen content of the sample obtained after NaOH based alkali pretreatment and a higher 6-O-methyl-β-d-galactose content in the agar after steam explosion, the chemical composition of the agars showed no significant difference. Agars extracted after steam explosion had melting temperature, gel strength and apparent modulus of elasticity lower than those of corresponding ‘native’ and alkali (NaOH) pretreated samples, but comparable to those of a commercial sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182734
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Enzymatic hydrolysis of cotton wastes. Effect of γ-ray pretreatments (1982)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 102 (1982), S. 187-197 
    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: Baumwollabfälle wurden einer verschieden dosierten γ-Bestrahlung unterworfen und in 10proz. NaOH-Lösungen aufgelöst. Die aus diesen Lösungen regenerierten Cellulosen wurden einer enzymatischen Hydrolyse unterzogen und der Verlauf der hydrolytischen Reaktion mit demjenigen an unbehandelten oder nur mit γ-Strahlen behandelten Cellulosen verglichen.Die einzelnen Muster wurden mittels Röntgenstreuung sowie Messungen des Polymerisationsgrades, der Feuchtigkeitsaufnahme und der Wasserretention charakterisiert. Es wurde eine wechselseitige Beziehung zwischen den durch die Vorbehandlungen hervorgerufenen strukturellen und morphologischen Modifizierungen und den Veränderungen der kinetischen Kenngrößen des enzymatischen Prozesses, im besonderen dem als Spezifizitätskonstante bezeichneten Verhältnis Vmax/Km festgestellt. Nur die Bestrahlung und die Auflösung gemeinsam ergaben eine bemerkenswerte Wirkungszunahme der enzymatischen Reaktion, während die Behandlung mit γ-Strahlen allein keine Zunahme der Hydrolyseausbeute bewirkte.
    Notes: Textile cotton wastes were irradiated with γ-rays at different doses and solubilized with 10% NaOH solutions. The regenerated products underwent enzymatic hydrolysis and their degradation pattern was compared with that of the cotton celluloses untreated or treated only with γ-rays. The different samples were characterized by measurements of X-ray diffraction, degree of polymerization, moisture regain and water retention. The structural and morphological modifications induced by the pretreatments were correlated with the variations of kinetic parameters, particularly the Vmax/Km ratio, defined as specificity constant. Only the combination of irradiation with dissolution pretreatments gave a considerable increase of hydrolysis reaction effectiveness.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1982.051020118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Peroxidase immobilized on acrylic copolymer beads (1975)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 48 (1975), S. 17-27 
    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: Das Enzym Peroxydase wurde nach Vorbehandlung mit Glycidylmethacrylat in Polyacrylamidgel immobilisiert. Das Enzym initiiert die Polymerisation von Acrylcomonomeren. Die Aktivität des festen Materials nimmt mit zunehmender Menge an Glycidylmethacrylat und mit zunehmender Reaktionsdauer zwischen dem Vinylmonomeren und dem Enzym zu, während sie in geringem Maße von der Konzentration des Acrylamids beeinflußt wird.Das erhaltene Gel zeigt eine schwache Diffusionsabhängigkeit. Die Km-Werte sind bei Verwendung von H2O2 und Guajakol gleich denen, die bei freier Peroxydase festgestellt wurden.Nach 150 h Lagerung bei Raumtemperatur oder nach der Gefriertrocknung wurde keine Stabilitätsentnahme des Enzyms beobachtet.Mittels kontinuierlicher Durchflußmessungen wurde, bei Verwendung von Guajakol als Substrat, verschiedene Adsorption der Reaktionsprodukte festgestellt.
    Notes: Horseradish peroxidase was immobilized onto crosslinked acrylamide beads after a pretreatment of the enzyme with glycidyl-methacrylate. The enzyme initiates the polymerization of the acrylic comonomers. The activity of the solid materials increases by increasing the amount of glycidyl-methacrylate and the time of reaction between the vinyl monomer and the enzyme, while it is not greatly influenced by the concentration of the acrylamides.The beads obtained showed little dependence on diffusion; the Km values using guaiacol and H2O2 as substrates were the same as for free peroxidase.No decrease in stability was observed after 150h storage at room temperature or after freeze-drying.By continuous flow measurements, using guaiacol or iodide as cosubstrate, a different adsorption of the reaction products was found.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1975.050480102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Differential scanning calorimetry and thermal gravimetric analysis of lignin blended with triglycidyl isocyanurate (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 228 (1995), S. 51-58 
    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: Mittels DSC und TG wurde die Reaktion zwischen Lignin und Triglycidylisocyanurat (TGI) mit Lignin-Gehalten von 0 bis 85 Gew.-% untersucht.Die DSC-Thermogramme der Lignin/TGI-Mischungen zeigen zwei Exotherme bei etwa 250 und 355°C, während die TG-Analysen im Stickstoffstrom einen einzigen Gewichtsverlust bei etwa 360°C zeigen.Wir schlagen vor, daß das erste exotherme Signal der Reaktionswärme zwischen den TGI-Epoxygruppen und den phenolischen Wasserstoffatomen des Lignins und das zweite Signal der Reaktionswärme der Verkohlung des Lignins entspricht. TG und IR-Spektroskopie unterstützen diese Folgerung.
    Notes: The thermal behaviour of lignin blended with triglycidyl isocyanurate (TGI) was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) over a range of lignin contents from 0 to 85 wt.-%.DSC thermograms of lignin/TGI blends show two exothermic peaks at about 250 and 355°C while TG analysis in nitrogen bears evidence of a single loss of weight at about 360°C. The first exotherm is suggested to correspond to the heat of bulk reaction between epoxy groups of TGI with phenolic hydroxy groups of lignin, and the second one to the heat of char formation of lignin. TG and infrared analyses suport this conclusion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052280105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Steam-exploded wheat straw fibers as reinforcing material for polypropylene-based composites. Characterization and properties (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 233 (1995), S. 149-166 
    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: Aus Weizenstrohfasern und Polypropylen (iPP) bzw. mit Maleinsäureanhydrid modifiziertem Polypropylen (iPPMA) wurden Composite hergestellt. Die Weizenstrohfasern wurden vor dem Einmischen in die Polypropylenmatrix einem Dampfexplosionsprozeß unterworfen, der bei Lignocellulosematerialien morphologische und strukturelle Veränderungen bewirkt, die zu einer Verbesserung der Wechselwirkungen mit der thermoplastischen Matrix führen können. Die modifizierte iPPMA-Matrix weist im Vergleich zur iPP-Matrix bessere mechanische Eigenschaften (Zug- und Schlagverhalten) und eine bemerkenswerte Verringerung der Wasseraufnahme, einer der Hauptnachteile von Compositen mit Naturfasern, auf. Die gute Grenzflächenhaftung in den iPPMA-Compositen kann mit den beim Mischen der Fasern mit der Polymerschmelze gebildeten kovalenten Esterbindungen zwischen den Maleinsäureanhydrid-Segmenten und den dampfbehandelten Fasern erklärt werden.
    Notes: Composites of wheat straw fibers with polypropylene (iPP) and maleic anhydride modified polypropylene (iPPMA) were prepared.Before being mixed with polypropylene matrices, the wheat straw fibers were subjected to a steam explosion process that induces morphological and structural changes in lignocellulosic materials. Such changes are able to enhance the interactions with the thermoplastic matrix.Compared with iPP, the modified matrix (iPPMA) has shown higher mechanical performances (tensile and impact behavior) and a remarkable decrease of water absorption, that is one of the main drawbacks of natural fiber composites.Finally, the presence of covalent bonds between maleic anhydride and steam-exploded (STEX) fibers, by means of an esterification reaction, produced during the melt-mixing process, can explain the resulting good interfacial adhesion found in iPPMA-based composities.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052330113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...