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  • American Institute of Physics  (53)
  • Wiley-Blackwell  (23)
  • 1995-1999  (40)
  • 1980-1984  (25)
  • 1970-1974  (11)
  • 1930-1934
  • 1920-1924
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  • 1
    Electronic Resource
    Electronic Resource
    Dilute solution of amylose in dimethylsuldoxide (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1177-1195 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements of light scatting, sedimentation equilibrium, sedimentation velocity, and viscosity were carried out on fractions of native amylose in dimethylsulfoxide at 25°C. The data for statistical radius as a function of weight-average molecular weight Mw suggested a stiff nature of this biopolymer in the solvent studied when interpreted in terms of Kirste's recent calculations with a stiff chain model. The data for sedimentation coefficient were consistent with this suggestion, and when analyzed in terms of the theory Hearst and Stockmayer for wormlike chain, a value of 233 Å2 was obtainedd for a/λ, where a is the length of a monomer unit projected on the chain axis and (2λ)-1is the persistence length of the wormlike chain. The intrinsic viscosity data gave a high a value as 0.91 for the exoponent in the Houwink-Mark-Sakuarada equation, in Substantial agreement with Cowie's prenious work.We attempted to interpret these data by use of the Eizner-Ptitsyn equation for wormlike chains, with omission of the free-drainage term and introduction of the a/λ value obtained from sedimentation data. It was found that, except in the region of Mw above one million, the observed values were fitted well by the E-P theory with a = 1.4 Å and (2λ)-1 = 87 Å. The disagreement in the high-molecular-weight region was tentatively attributed to excluded volume effect. The a value obtained suggests that the molecular conformation of amylose in dimethylsulfoxide is predominantly helical, in contrast to that of the same polymer in aqueous solutions of simple electrolyte. It was also found that a similar value of a was derived from our data for the second virial coefficient and partial specific volume if the molecule was assumed to be essentially rodlike.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120520
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  • 2
    Electronic Resource
    Electronic Resource
    Biosynthesis of the Indole Alkaloids. Cell-free Systems from Catharanthus roseus PlantsFor preliminary reports of this work, see [1-4]. (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 2088-2101 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cell-free systems from Catharanthus roseus plants are utilized for various studies relating to the biosynthesis of indole alkaloids. Tryptamine (5) and secologanin (6), two fundamental building units, are shown to be incorporated into the alkaloid vindoline (7). In another study, catharanthine (18) and vindoline (7) are utilized by this enzyme system and coupled to the important bisindole biointermediate 3′,4′-anhydrovinblastineThe previously [20] used name for 17, 3′, 4′-dehydrovinblastine, is incorrect. (17). The latter substance is, in turn, incorporated and converted to the natural alkaloids leurosine (8), Catharine (9) and vinblastine (10), thereby providing information about the biosynthesis of these complex molecules. High pressure liquid chromatography assay of the enzymic mixture sheds light on the enzymes involved in the coupling of 18 and 7.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650716
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  • 3
    Electronic Resource
    Electronic Resource
    Total Synthesis of Indole and Dihydroindole Alkaloids. XVIIIPart XVII: [1].. Isomers and analogues of vinblastine (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 366-374 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and conformational analysis of (3′R)-3-hydroxyleurosidine (5), (3′S)-3-hydroxyleurosidine (10), (3′S)-3-acetoxy-4′-deoxyleurosidine (15), (3′R)-3-acetoxy-4′-deoxyleurosidine (23), (3′R)-3-acetoxy-4′-deoxyvinblastine (16), (3′S)-3-acetoxy-4′-deoxyleurosidine (28) is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630206
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  • 4
    Electronic Resource
    Electronic Resource
    Direct polymerization of N-carboxy anhydride of L-glutamic acid (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2127-2137 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new method of polymerization of the N-carboxy anhydride (NCA) of glutamic acid is presented by which poly(glutamic acid) is obtained directly from the NCA without protecting its carboxyl group. The principle underlying is that by adjusting the mole ratio of the initiator butylamine, [I], to the monomer, [A], butylamine can be used as protecting agent for the carboxyl group of the NCA so that the rest of butylamine acts as initiator in the heterogeneous polymerization in acetonitrile. Quantitative conversion was obtained for an [A]/[I] ratio of 1. In analogy to other heterogeneous polymerizations of NCAs in acetonitrile, this is due to the formation of the helix during polymerization, which was confirmed by IR absorption and X-ray diffraction measurements. As the [A]/[I] ratio increases, the conversion, the helix content of the resultant polymer, and the amount of butylamine combined with it decrease drastically. It is suggested that “copolymerization” of the amine-protected and unprotected NCAs occurs, giving rise to a partially helical chain, whose contents of the amine-protected side chains and accordingly of the helix are the higher the smaller the [A]/[I] ratio.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820802
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation of poly(aryleneethynylene)-type copolymers containing flexible linking methylene units. Optical properties of the copolymers suggesting occurrence of energy transfer between π-conjugated local units (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2201-2207 
    Details
    ISSN: 0887-624X
    Keywords: poly(aryleneethynylene) ; palladium-catalyzed ; copolymer ; optical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladium-catalyzed polycondensation between 2,5-diiodo-3-hexylthiophene I-Th(Hex)-I with mixtures of p-diethynylbenzene HC≡C - Ph - C≡CH and α,ω-diethynylalkane HC≡C(CH2)lC≡CH (l = 3 or 8) gives poly(aryleneethynylene) PAE-type copolymers [C≡C(CH2)lC≡C - Th(Hex)]m[C≡C - Ph - C≡C - Th(Hex)]n containing the methylene unit. The copolymers have a molecular weight (Mn) of about 1.2 × 104 as determined by GPC (polystyrene standard) and are considered to possess essentially a random sequences in view of the  - C≡C(CH2)lC≡C -  and  - C≡C - Ph - C≡C -  units as judged from their UV-visible spectra. By the incorporation of the (CH2)l unit, the λmax position of the corresponding PAE homopolymer [C≡C - Ph - C≡C - Th(Hex)]n is shifted to a shorter wavelength. However, the copolymers give rise to a photoluminescence PL peak essentially agreeing with a PL peak of the homopolymer, suggesting occurrence of energy transfer in the copolymer. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2201-2207, 1998
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Reversible oxygenation of heme bound to polyvinylpyridine and polyvinylimidazole (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 2147-2159 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction between heme bound to poly-4-vinylpyridine (PVP) or poly-N-vinyl-2-methylimidazole (PVMI) and molecular oxygen (O2) was studied. In this paper, the reactions of some types of heme with O2 in organic solvents, particularly in N,N-dimethylformamide (DMF) were discussed. The free heme not bound to an axial base was easily oxidized irreversibly to hemin in DMF with bubbled O2. The hemochromogens complexed with pyridine, imidazole, or their polymeric derivatives such as PVP and PVMI bound O2 to one of the axial coordination sites. The characteristic absorption band assignable to the resulting oxygenated heme was observed at 402 nm. This absorption band could be changed back to the characteristic band of the reduced hemochromogen at 418 nm by removing O2 dissolved in the DMF solution by a vacuum or by a stream of nitrogen. Thus, the hemochromogens bound to the synthetic polymers were found to adsorb and desorb O2 reversible in DMF.When the polymeric ligands were used, the equilibrium constants in the complexation of heme with these polymers were about 102 times as large as those of the corresponding monomeric ligands. The oxygenation rates and the capacities of O2 of the polymeric hemochromogens were larger than those of the monomeric hemochromogens. In addition, the oxygenation rate of the polymer complex was changeable owing to the conformational change of the polymeric ligand; this rate increased about ten times under the optimal condition.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1974.360131015
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  • 7
    Electronic Resource
    Electronic Resource
    The differential refractive index increments of statistical styrene/acrylonitrile/methyl methacrylate terpolymers (1972)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 25 (1972), S. 163-169 
    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 Brechungsindexinkrement von acht verschieden zusammengesetzten Terpolymeren aus Styrol, Acrylnitril und Methylmethacrylat wurde in Dimethylfoirmamid und in Butanon bestimmt. Aus der infrarotspektroskopisch ermittelten Zusammensetzung der Copolymeren und den Brechungsinkrementen der Homopolymeren wurden die Brechungsinkremente der Terpolymeren berechnet. Das ptrrtielle azeotrope Terpolymere besitzt ein konstantes Brechungsinkrement während der Terpolymerisation, während die aus anderen Monomermischungen erhaltenen Werte sich mit dem Umsatz ändern.
    Notes: The differential refractive index increment was measured for statistical styrene/acrylonitrile/methyl methacrylate terpolymers of eight different compositions in dimethylformamide and in butanone. With the terpolymer composition obtained from infrared absorption and the differential refractive index increments of the homopolymers, the differential refractive index increments of terpolymers are calculated. The partial azeotropic terpolymer gives a constant value in the course of terpolymerization. The differential refractive index increment of a terpolymer synthesized from other monomer feed than the azeotropic composition changes with conversion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1972.050250115
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  • 8
    Electronic Resource
    Electronic Resource
    Cell movements in a living mammalian tissue: Long-term observation of individual cells in wounded corneal endothelia of cats (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 25-39 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although the cells in tissues are known to be motile under special conditions (e.g., during tissue turnover or wound healing), there are not many reports that polygonal cells covering an area without leaving any gaps are also capable of movement. In the present study, cell movements (cell shifting and rearrangement) in a living mammalian eye tissue were documented by identifying and locating individual cells over intervals as long as 100 days. Cat corneal endothelium, a monolayered cell sheet, was wounded by removing a small number (about 180) of endothelial cells from the internal lining of the cornea. Healing of the wounded tissue was observed with a wide-view specular microscope applied to the outer surface of the cornea, enabling us to identify individual cells for as long as two to three months.Cells surrounding the wound underwent areal enlargement, elongated toward the wound, and shifted to cover the wound surface. During days 4-7, cells became rearranged by changing neighbors in such a way that they retained their enlarged size but recovered their non-elongated, original shape. This pattern of cell rearrangement was interpreted by a computer simulation which assumed that cells shorten their boundary length while maintaining contacts with contiguous cells. After day 7, the enlarged cells adjacent to the wounded area gradually contracted and pulled surrounding cells toward the wounded area. These movements were followed by a temporary halt in cell shifting, then by a recovery of shifting and cell elongation. These movements are interpreted as a result of the contractility of endothelial cell microfilaments.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051740104
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  • 9
    Electronic Resource
    Electronic Resource
    Multi-electron transfer in photoelectrochemical processes (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 115-117 
    Details
    ISSN: 1042-7147
    Keywords: photoelectrochemistry ; multi-electron transfer ; semiconductor particle ; light excitation ; molecular conversion reactions ; 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
    Notes: Simultaneous bidirectional forward and backward electron transfers take place on a light-exited semiconductor particle, even at the same geometric site. The potentials of the electron pathways are different, giving rise to two independent molecular conversion reactions. This type of multi-electron transfer reactions is overviewed and the stepwise unidirectional multi-electron transfer on the excited semiconductor particle is also described.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1995.220060304
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of the number of crosslinks in collagens from mechanical properties of swollen fibers (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 1577-1586 
    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
    Notes: A method for the determination of crosslink density for collagen fibers was proposed. The number of interchain crosslinkages in whale ligament and rat-tail tendon was estimated by applying an usual rubber elasticity theory. Collagen fibers swollen in a solution composed of equal volumes of 8M LiBr aqueous solution and diethylene glycol monoalkyl ether showed a typical rubber elasticity. The energy components to total retractive forces were similar in order in magnitude for crosslinked natural rubbers, namely, below 0.3. It was found that no intermolecular crosslinkage occurs between tropocollagen molecules in tendon from a 2-month-old rat, while there are about 12 crosslinking sites per molecule in tendon from a 10-month-old rat and 15 sites in whale ligament. The number, type, and crosslinking sites in the tendon crosslinked with 1,3-bis(vinylsulfonyl)-2-propanol is also discussed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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