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  • 1990-1994  (14)
  • 1985-1989  (2)
  • 1970-1974  (4)
  • 1950-1954  (1)
  • 1925-1929  (3)
  • 1915-1919  (1)
  • 1910-1914  (2)
  • Chemistry  (27)
  • Polymer and Materials Science  (12)
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  • 1
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The oscillatory and steady shear rheological properties of concentrated solutions of proteoglycan subunit (PGS) and aggregate (PGA) from bovine articular cartilage have been studied using a Rheometrics fluids spectrometer. At comparable concentrations in the physiological range tan δ increases from 0.5 to 1.0 for PGA as the oscillation frequency (ω) increases from 10-1 to 102 rads / s, compared to a decrease from 40 to 5 for PGS. Thus PGA solutions exhibit predominantly elastic response whereas those of PGS exhibit primarily viscous behavior. PGA solutions show pronounced shear-thinning behavior at all shear rates (γ) in the range 10-2 〈 γ (s-1) 〈 10 2, whereas PGS solutions exhibit predominantly Newtonian flow. For PGA, the small-strain complex viscosity η* (ω) is substantially smaller than the steady-flow viscosity η (γ) at comparable values of ω and γ. These observations indicate that the presence of proteoglycan aggregates leads to formation of a transient or weak-gel network. Since aggregation leads to a large increase in molecular hydrodynamic volume and hence in the relaxation times for macromolecular rotation, it appears that role of aggregate formation is to shift the linear viscoelastic response from the terminal viscous flow into the plateau elastomeric regime of relaxational behavior. Normal or pathological changes that produce a decrease in aggregation will result in a loss of elastomeric behavior of the proteoglycan matrix.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 1175-1183 
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The temperature dependence of hydrogen isotope exchange rates for lysozyme in 5 molal aqueous glycerol and for poly (D,L-alanine) in a range of glycerol concentrations from 0 molal to 8 molal have been determined. The activation enthalpy of base-catalyzed exchange for poly (D,L-alanine) in water is 4 kcal/mol and passes through a minimum at about 2 molal glycerol before returning to a value of 4 kcal/mol at 4 molal glycerol. Exchange rates for lysozyme have been analyzed with transition state and Kramers's theories. The activation parameters for exchange of protons in lysozyme in the presence of 5 molal glycerol show a similar qualitative behavior to those determined for exchange in the absence of glycerol [R. B. Gregory et al. (1982) Biochemistry 24, 6523-6530]. The activation enthalpies and entropies for the fast-exchanging protons show a gentle increase as H(t), the number of hydrogens remaining unexchanged, decreases. By contrast, the activation parameters for the slowest exchanging protons [H(t) 〈 20] increase dramatically as H(t) decreases. As in water, the activation parameters for exchange of the fast- and slow-exchanging protons in glycerol solution are characterized by two distinct compensation temperatures (510 ± 100 K for the fast protons and 340 ± 40K for the slow protons). These values are not significantly different from those determined for exchange in water.The activation parameters, ΔH
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Microbiological Transformations of Nonsteroidal Structures, V. Microbiological Reactions of Substituted 1-Ethyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acids1-Ethyl-7-methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (1) is transformed to the methyl ester by Streptomyces surinam. Penicillium adametzi hydroxylates the substrate at the 7-methyl substituent, whereas 1 -ethyl-8-methoxy-5-methyl-4-oxo- 1,4-dihydroquinoline-3-carboxylic acid (4) is hydrolyzed to the free phenol by the same fungi. l-Ethyl-4-oxo-1,4,6,7,8,9-hexahydrobenzo[g]quinolinc-3-carboxylic acid (6) is hydroxylated in 7 - and 8-position by Penicillium adametzi, in 6- and 7- (or 8-) position by Streptomyces achromogenes and in 6-position by Sporotrichum sulfurescens. 5-Ethyl-8-oxo-2,3,5,8-tetrahydrofuro[2,3-g]quinoline-7-carboxylic acid (10) undergoes only a hydrolytic cleavage of the dihydrofuranering.
    Notizen: 1-Äthyl-7-methyl-4-oxo-1,4-dihydrochinolin-3-carbonsäure (1) wird durch Streptomyces surinam in den Methylester umgewandelt. Penicillium adametzi hydroxyliert das Substrat am 7-Methylsubstituenten, während bei der 1 -Äthyl-8-methoxy-5-methyl-4-oxo- 1, 4-dihydrochinolin-3-carbonsäure (4) mit dem gleichen Pilz nur eine Phenolätherspaltung eintritt. 1-Äthyl-4-oxo-l,4,6,7,8,9-hexahydrobenzo[g]chinolin-3-carbonsäure (6) wird von Penicillium adametzi in 7- und 8-, von Streptomyces achromogenes in 7-(oder 8-) und 6- sowie von Spororrichum sulfurescens in 6-Stellung hydroxyliert. 5-Äthyl-8-oxo-2,3,5,8-tetrahydrofuro[2,3-g]-chinolin-7-carbonsäure (10) zeigt nur eine hydrolytische Spaltung des Dihydrofuranringes.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 11 (1928), S. 731-750 
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: L'étude de la conductibilité des silicates aux températures élevées peut servir à déceler et à suivre des réactions dont ces silicates peuvent être le siège.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Microbiological Transformations of Nonsteroidal Structures, III. Hydroxylation of 5-Alkyl-2-(benzenesulfonylamino)pyrimidines and Structurally Related Antidiabetics5-Alkyl-2-(arylsulfonylamino)pyrimidines (1-5 and 11-16) have been hydroxylated microbiologically Propyl, butyl, and isobutyl groups were hydroxylated at C-2, ethyl groups at C-1, isopropyl groups at C-1 and C-2, and neopentyl groups at C-3, respectively, by Streptomyces griseolus. The sulfonylurea part of the antidiabetics glibenclamid (25) and glisoxepid (29) was degradated to sulfonamide; in addition, hydroxyl groups were introduced into the 2- and 4-positions of the cyclohexane ring of 25.
    Notizen: 5-Alkyl-2-(arylsulfonylamino)pyrimidine (1-5 und 11-16) wurden mikrobiologisch hydroxyliert. Mit Streptomyces griseolus wurden Propyl-, Butyl- und lsobutylgruppen an C-2, äthylgruppen an C-1, Isopropylgruppen an C-1 und C-2, sowie Neopentylgruppen an C-3 hydroxyliert. Die Antidiabetika Glibenclamid (25) und Glisoxepid (29) mit Sulfonylharnstoff-Struktur wurden zu Sulfonamiden abgebaut, ferner wurden in 2- und 4-Stellung des Cyclohexanrings von 25 Hydroxylgruppen eingeführt.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 177 (1929), S. 137-144 
    ISSN: 0863-1786
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 182 (1929), S. 74-92 
    ISSN: 0863-1786
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Während die Brom-Austreibung in Gegenwart von Sulfaten in allen Konzentrationen des betreffenden Salzes, je nach dem an- gewandten Sulfat, entweder beschleunigt oder verzögert wird, wirken alle Chloride niederer Konzentration ausschließlich verzögernd. Überall hat man ein Maximum der Verzögerung im Gebiet von etwa n/1-Endkonzentration. Es ergibt sich folgende Reihe ab- nehmender Verzögerung: \documentclass{article}\pagestyle{empty}\begin{document}$$ Me^I Cl 〉 Me^{II} Cl_2 \ge Me^{III} Cl_3. $$\end{document}Eine spezifische Kationenwirkung ist nicht feststellbar. HCl ver- hält sich genau wie ein neutrales Chlorid. Das H-Ion liegt in seiner Wirkung zwischen den ein- und mehrwertigen Kationen.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 2 (1987), S. 273-282 
    ISSN: 0887-3585
    Schlagwort(e): protein-DNA interactions ; hydroxylamine mutagenesis ; dimerization ; protein structure-function ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: EcoRI endonuclease mutants were isolated in a methylase-deficient background following in vitro hydroxylamine mutagenesis of plasmid pKG2 (Kuhn et al.: Gene 44:253-263, 1986). Mutants which survived high-level endonuclease expression (IPTG induction) were termed null mutants. Sixtytwo of 121 null mutants tested by Western blot contained normal levels of endonuclease cross-reacting protein. The complete endonuclease gene was scquenced for 27 null mutants. This group was found to consist of 20 signle base-change missense mutations, 6 double mutations, and 1 triple mutation. Ten of the 20 signle mutations were clustered between residues 139 and 144. When examined with respect to the structure of the EcoRI-DNA complex (McClarin et al.: Science 234:1526-1541, 1986), these alterations werre found to fall predominantly into two classes: substitutions at the protein-DNA interface or substitutions at the protein-protein (dimer) interface. Protein from several of the mutants was purified and sized by using HPLC. Wild-type EcoRI endonuclease and protein from three of the DNA interface mutations (A1a139→Thr, Gly140→Ser, Arg203→Gln) appeared to be dimeric, while protein from subunit interface mutations (Glu144→Lys, Glu152→Lys, Gly210→Arg) migrated as monomers.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 36 (1990), S. 598-604 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: In 1954, G. I. Taylor derived an expression for an apparent axial dispersion coefficient for mass transfer in turbulent flow under the assumption of no mass transport between the tube wall and the fluid inside the tube. Taylor's expression has been verified in a number of experimental efforts for both mass and heat transfer.This work extends the results of Taylor to the case where there is a significant transport of heat from the tube wall to the fluid in the tube, such as in a double-pipe heat exchanger. Using an analysis similar to Taylor's, it is shown that the apparent axial dispersion coefficient is about one order of magnitude larger when a large radial gradient is present. Experimental data on a double-pipe heat exchanger show significantly improved correspondence with a dispersion-based model of the system when the larger dispersion coefficients are used.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 2 (1990), S. 275-279 
    ISSN: 0899-0042
    Schlagwort(e): nucleotide analogue ; antiviral ; chiral separation ; complexation ; ion-pairing ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An acylonucleotide analogue, 1-[3-hydroxy-2-(phosphonyl-methoxy)propyl]cytosine (HPMPC), has shown activity against herpes simplex Type I and Type II viruses. An HPLC separation of the R- and S-enantiomers of HPMPC by ligand exchange using a mobile phase containing phenylalanine as the chiral modifier and copper(II) as the metal ion is reported.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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