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  • 1995-1999  (13)
  • 1975-1979  (12)
  • 1970-1974  (10)
  • 1925-1929
  • 1905-1909
  • Chemistry  (35)
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2563-2575 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A dc conductivity study of native and denatured samples of sodium salts of calf thymus DNA in the solid state was performed at different temperatures and water content. From the results obtained it appears that the major carrier of conductivity is either electronic or ionic, depending upon the temperature of the sample, the water content, and the fact that the conductivity of native samples is higher than that of the denatured ones. These results have been confirmed by dc conductivity studies of poly U and poly A.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 1054-1054 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 81 (1998), S. 153-162 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, absolute configuration, and olfactive evaluation of (-)-(E)-α-trans-bergamotenone (= (-)-(1′S,6′R,E)-5-(2′,6′-dimethylbicyclo[3.1.1]hept-2′-en-6′-yl)pent-3-en-2-one; (-)-1), as well as its homologue (-)-19 are reperted. The previously arbitrarily attributed absolute configuration of 1 and of (-)-α-trans-bergamotene (= (-)-(1 S,6R)-2,6-dimethyl-6-(4-methylpent-3-enyl)bicyclo[3.1. 1]hept-2-ene; (-)-2), together with those of the structurally related aldehydes (-)-3a,b and alcohols (-)-4a,b, have been rigorously assigned.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dye-sensitized photooxygenation (1O2-reaction) of the symmetrically 3,3-dialkyl-substituted allyl alcohols 1-6 (A, Table 1) and the E- and Z-isomers of the 3-methyl-3-alkylsubstituted allyl alcohols 7-11 (A1, Table 2) has been studied. The α, β-epoxyaldehydes B and B1 and the β-hydroperoxy-homoallyl alcohols C, C1 and D1 were practically the sole oxygenation products formed. The rate and selectivity of the 1O2 additions were found to be markedly dependent on the degree of substitution (i.e. H-availability) at the allyl position which is Z-orientated to the carbinol group. The allyl alcohols with a Z-3-methyl group, 1 and the E-isomers of 7 to 10, showed practically the same reactivity towards 1O2 and formed only the two oxygenation products of type B1 and C1 (ratio close to 60:40). In contrast, the allyl alcohols with a Z-3-methylene group, 2 and the Z-isomers of 7 to 9, reacted more slowly with 1O2 and yielded all the three possible products B1, C1 and D1 in a very different ratio of ∼ 80:10:10. However, from both the E- and Z-isomers of the alcohols 7 to 10 the formations of the two oxygenation products were always strongly favoured (85-100%) which result from 1O2 additions at the disubstituted side of the double bond. This behaviour is thus completely analogous to that of the corresponding trisubstituted olefins previously studied [1]The same side-specific selectivity in 1O2 ene additions to several E/Z-isomeric and deuterium-labelled olefins has also been described recently by C.M. Stephenson et al. [2] (we thank Dr. V. Rautenstrauch and Prof. C.W. Jefford for informing us about this work). The similar behaviour of enol ethers, which react with 1O2 preferentially at the RO-substituted side, had been observed earlier by C.S. Foote et al. [3] and extended to numerous derivatives by J.M. Conia et al. [4] [5]. and follows a new selection rule, termed syn-preference [1], in the ene addition of 1O2.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 2905-2920 
    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: Cotton fiber was treated with aqueous trimethylbenzylammonium hydroxide (Triton B) at concentrations over the range 25%-40%. After complete removal of the swelling agent, the samples were evaluated for the extent of swelling, strength and elongation, birefringence, moisture regain, density, crystallinity, x-ray diffraction patterns, and microfibrillar morphology. Electron-microscopical examination and other evaluation of fine structure properties revealed that the nature of swelling is intercrystalline up to 30% concentration of Triton B, and intracrystalline beyond that. Although the swelling as measured by propanol-2 retention after treatment with 30% Triton B is about twice as much as that of the control, the original structure remains almost unchanged except for some gain in strength and elongation and increase in moisture regain. At 32% Triton B concentration and beyond, rapid decrystallization takes place, accompanied by a fall in birefringence, density, and crystallinity index. X-Ray analysis showed significant loss of lateral order and partial conversion of cellulose I to cellulose II at 35% and 40% Triton B concentrations. The results indicate that, used at the critical concentration of 30%, Triton B can be a useful swelling agent for cotton fibers as it opens up the fine structure of cellulose considerably without impairing any important physical properties.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 26 (1996), S. 353-357 
    ISSN: 0887-3585
    Keywords: VEGF ; angiogenesis ; tumor vascularization ; inclusion bodies ; cysteine mutants ; X-ray crystallography ; crystals ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Vascular endothelial growth factor (VEGF) is a potent angiogenic factor with a unique specificity for vascular endothelial cells. In addition to its role in vasculogenesis and embryonic angiogenesis, VEGF is implicated in pathologic neovascularization associated with tumors and diabetic retinopathy. Four different constructs of a short variant of VEGF sufficient for receptor binding were overexpressed in Escherichia coli, refolded, purified, and crystallized in five different space groups. In order to facilitate the product on of heavy atom derivatives, single cysteine mutants were designed based on the crystal structure of platelet-derived growth factor. A construct consisting of residues 8 to 109 was crystallized in space group P21, with cell parameters a = 55.6 Å, b = 60.4 Å, c = 77.7 Å, β = 90.0°, and four monomers in the asymmetric unit. Native and derivative data were collected for two of the cysteine mutants as well as for wild-type VEGF. © 1996 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 20 (1997), S. 469-474 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bubble columns are commonly used in industry for polluted gas treatment. Based on the same principle, the droplet column which is not widely known in the literature, uses much higher gas velocities, up to 14 m/s. This study concerns the hydrodynamics and mass transfer in this apparatus, in presence or absence of solid particles. Our results have demonstrated the impact of dusts on mass transfer performance giving rise to an increase in the kL aL coefficient with decreasing particle size. However, no influence of dust on the hydrodynamics of the column has been demonstrated within the studied particle size range.A study of liquid holdups obtained by three different methods is also carried out. Our results are comparable, thus validating the methods used.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1434-1948
    Keywords: MS-325 ; Angiography ; MRI contrast agent ; NMR spectroscopy ; Interaction with HSA ; Gadolimium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The physicochemical characterization of MS-325 [trisodium {4-(R)-[(4,4-diphenylcyclohexyl)phosphanooxymethyl]-3,6,9-triaza-3,6,9-tris(methoxycarbonyl)undecanedioato}gadolinium(III)], a new derivative of Gd-DTPA {Magnevist®: dimeglumin [{3,6,9-triaza3,6,9-tris(methoxycarbonyl)undecanedioato}gadolinium(III)], presented as a potentially useful angiographic contrast agent, was carried out in various media. Water solution, protein-containing solution, phosphorylated metabolites solution, and Zn2+-containing solution were investigated using different NMR techniques such as water 1H nuclear magnetic relaxation rates, water 17O transverse relaxation rates, and 31P longitudinal relaxation rates of phosphorylated metabolites. The proton relaxivity of MS-325 in water was found to be higher than that of the parent compound Gd-DTPA; this can be attributed to the longer rotational correlation time (τR) of the hydrated complex, and possibly to an apparently shorter mean distance (r) between the protons of the coordinated water molecule and the gadolinium ion. The kinetic and thermodynamic stability of MS-325 in solutions containing phosphorylated metabolites (ATP, phosphocreatine and inorganic phosphate) were measured by 31P relaxation rate analysis and found to be higher than for Gd-DTPA. Similarly, the Zn2+ transmetallation process studied by proton relaxometry is slower than for the same reference compound. Finally, an analysis of the noncovalent binding of MS-325 to serum proteins by proton relaxometry showed that MS-325 interacts with human serum albumin (HSA) and that the association constant of this interaction is equal to 6100 ± 2130 M-1. A peak relaxivity of approx. 50 s-1mM-1 was determined at 25 MHz for the protein-bound paramagnetic complex. This value is lower than the maximal relaxivity predicted for a paramagnetic center totally immobilized at the surface of the protein.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 181-192 
    ISSN: 0887-6266
    Keywords: ternary solutions ; solvent quality ; polystyrene-dioctyl phthalate ; light scattering ; Boger fluid ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymer solvent interactions in the ternary system high molecular weight polystyrene (HMPS), low molecular weight polystyrene (LMPS), and dioctyl phthalate (DOP) have been characterized by means of intrinsic viscometry (IV), dynamic light scattering (DLS), and static light scattering (SLS). Excluded volume exponents have been extracted from the scaling of intrinsic viscosity and translational diffusivity with polymer molecular weight for a mixed solvent of 13 wt % LMPS/87 wt % DOP. The value of the excluded volume exponent, v = 0.45, indicates that HMPS in the mixed solvent DOP/LMPS has apparently assumed a reduced conformation relative to the theta condition. However, SLS measures of the second virial coefficient (A2) confirm that DOP is a theta solvent at our experimental temperature of 22°C and indicate that the addition of LMPS increases A2. SLS also suggests that neither solvent component is strongly preferentially adsorped into the HMPS coil. Our system then is a mixture of a theta solvent and a good solvent that exhibits poor solvent scaling behavior. We believe this to be the first demonstration of such behavior in a system that does not exhibit appreciable preferential adsorption. We conclude by examining our observations in the context of current descriptions of mixed solvent thermodynamics. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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  • 10
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of linear weak polyelectrolytes containing β-cyclodextrin pendant groups was synthesized by chemical modification of poly(1-vinylimidazole). Studies on their solution behaviour as a functon of pH and the nature and ionic strength of added salts showed original features which are explained in terms of competitive residue-residue and residue-solvent interactions and anion binding to cyclodextrin moieties.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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