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  • Polymer and Materials Science  (6)
  • Computational Chemistry and Molecular Modeling  (2)
  • dillapiol  (2)
  • 1
    Electronic Resource
    Electronic Resource
    In vivo effect of mixtures of allelochemicals on the life cycle of the European corn borer, Ostrinia nubilalis (1990)
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 17-22 
    Details
    ISSN: 1570-7458
    Keywords: Phenylpropanoid ; dillapiol ; tenulin ; phenylheptatriyne (PHT) ; polysubstrate monooxygenases (PSMO) ; European corn borer (ECB) ; growth reduction ; allelochemical interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le dillapiole, un phénylpropanoide monomère d'un lignan et contenant un groupement méthylènedioxyhphényl (MDP), a la capacité d'inhiber in vitro les enzymes d'oxydations multiples à cytochrome P-450 (PSMO) utilisées par la pyrale du maïs (ECB), Ostrinia nubilalis, pour detoxifier les substances allélochimiques. Les composés contenant un groupe MDP comptent parmi les plus nombreux et puissants synergistes d'insecticides. Cependant, aucun synergisme n'est observé lorsque le dillapiole est ingéré par la pyrale en association avec l'une ou l'autre ou les deux substances secondaires insecticides des Astéraceae, la lactone sesquiterpène ténuline ou/et le polyacétylène phénylheptatriyne (PHT). Plutôt, le dillapiole est une toxine qui diminue la prise de poids des larves et retarde leur développement. Les effets toxiques sont plus importants avec le dillapiole seul que lorsque celui-ci est associé à la ténuline ou/et au PHT. Les expications possibles de ces résultats sont discutées.
    Notes: Abstract The phenylpropanoid, dillapiol, a compound capable of inhibiting the activity of cytochrome P-450 epoxidase in microsomal preparations of midguts of the European corn borer (ECB), Ostrinia nubilalis Hubner (Lepidoptera), did not enhance the toxicity of two insecticidal allelochemicals from the Asteraceae: the sesquiterpene lactone, tenulin or the phenylacetylene, phenylheptatriyne, when ingested simultaneously. Dillapiol alone was toxic to ECB larvae, and inhibited their growth. Possible reasons for the lack of synergism or potentiation by dillapiol of the insecticidal activity of the other allelochemicals are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349591
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  • 2
    Electronic Resource
    Electronic Resource
    Ab initio calculations of phenylene ring motions in polyphenylene oxide (1986)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 29 (1986), S. 563-578 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An important class of polymers is comprised, in part, of 1,4-disubstituted phenylene groups. It is widely believed that large amplitude phenylene torsional motions play a critical role in determining such physical properties as the toughness and degree of crystallinity of these polymers. We have studied what is perhaps the simplest polymer in this class, polyphenylene oxide (PPO), using ab initio quantum chemistry methods to determine the conformational properties, torsional potential energy functions, and vibrational frequencies. From our calculations on dimer (diphenyl ether) and trimer (para-diphenoxy benzene) fragments emerges a qualitative description of the mechanism of phenylene rotation in the polymeric material.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560290328
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  • 3
    Electronic Resource
    Electronic Resource
    Theoretical determination of the X 2Σ+ and A 2Π potentials of CsO using relativistic effective core potentials (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 483-490 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Theoretical potential energy curves are computed for the X 2Σ+ and A 2Π states of CsO using a relativistic effective core potential and a large valence Gaussian basis set. Seventeen electrons are correlated by a CI(SD) calculation from each HF reference. We find the X 2Σ+ state lower by 497 and 726 cm-1 at the HF and CI(SD) levels. Our calculated ωe of 312 cm-1 for the X 2Σ+ state agrees well with experimental values deduced from studies in matrices.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230218
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  • 4
    Electronic Resource
    Electronic Resource
    Insecticidal defenses of Piperaceae from the neotropics (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 801-814 
    Details
    ISSN: 1573-1561
    Keywords: Piperaceae ; botanical insecticide ; isobutyl amides ; lignans ; dillapiol ; conocarpan ; piperlonguminine ; European corn borer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Insecticidal and growth-reducing properties of extracts of 14 species of American neotropical Piperaceae were investigated by inclusion in diets of a polyphagous lepidopteran, the European corn borer,Ostrinia nubilalis. Nutritional indices suggested most extracts acted by postdigestive toxicity.Piper aduncum, P. tuberculatum, andP. decurrens were among the most active species and were subjected to bioassay-guided isolation of the active components. Dillapiol was isolated from the active fraction ofP. aduncum, piperlonguminine was isolated fromP. tuberculatum, and a novel neolignan fromP. decurrens. The results support other studies on Asian and AfricanPiper species, which suggest that lignans and isobutyl amides are the active defence compounds in this family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033462
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  • 5
    Electronic Resource
    Electronic Resource
    Nmr studies on the presence of domain structures in polysaccharides. II. 1H spin--lattice relaxation time dispersion (1988)
    New York : Wiley-Blackwell
    Biopolymers 27 (1988), S. 1619-1626 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The behavior of 1H-nmr spin-lattice relaxation times as a function of frequency is examined for powders of α- and β-cyclodextrins, dextran B512F, and their “deuterated” analogues, where deuterium replaces exchangeable protons. A crossover from two- to one-component relaxation decays is observed with increasing frequency (ν). By considering the effect of spin diffusion in spin-lattice relaxation measurements as a function of the frequency, estimates of domain sizes (∼ 7-10 Å) consistent with the lower limit of spatial resolution of the Goldman-Shen experiments are obtained.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360271007
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  • 6
    Electronic Resource
    Electronic Resource
    Nmr studies on the presence of domain structures in polysaccharides (1987)
    New York : Wiley-Blackwell
    Biopolymers 26 (1987), S. 849-861 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variety of nmr transient techniques demonstrate the absence of domain structures in powders of α- and β-cyclodextrins, dextran B512F, and their “deuterated” analogs where deuterium replaces exchangeable protons. Cyclodextrins and dextran are inferred to be homogeneously ordered and disordered one-phase systems, respectively. We show how erroneous results concerning the presence and sizes of rigid and mobile domains can be reached from the interpretations of two-component free induction decays and spin-lattice relaxation behavior of polysaccharides. In our approach, we have measured 1H free induction decays and lineshapes, and 1H spin-lattice and dipolar relaxation times, in addition to using Goldman-Shen experiments and 13C cross-polarization magic-angel sample spinning. Self-consistent nmr results are suggested as essential means to corroborate conclusions concerning domain structures in biopolymers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360260606
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  • 7
    Electronic Resource
    Electronic Resource
    Photomicroscopic measurement of the diffusion layer around mercury drop electrodes: Part I, description of the electrochemical system (1990)
    Weinheim : Wiley-Blackwell
    Electroanalysis 2 (1990), S. 89-97 
    Details
    ISSN: 1040-0397
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A special electrochemical system has been developed to determine the optimum conditions for the stirred deposition step of anodic stripping voltammetric techniques with the sessile mercury drop electrode (SMDE) in order to get a reproducible flux that is predictable on sound theoretical grounds. The sessile Hg drop is formed at the upper part of a vertical capillary, which is placed coaxially below a rotating disc electrode that serves as both an auxilliary electrode and a stirrer. This system permits the visualization of the hydrodynamic flux, diffusion layer, and screening effects of the capillary around the mercury drop.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140020203
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  • 8
    Electronic Resource
    Electronic Resource
    Intravascular radiopaque catheters in the dog: Tissue reaction and possible lead lossThis represents part of the work done for the thesis requirement for a M.A. degree from the Department of Anatomy and Physiology, Indiana University (Bloomington). (1973)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 7 (1973), S. 167-178 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Male mongrel dogs were divided into two groups and placed in urine collection cages for 24-hr urine samples. One group was implanted with sterile radiopaque polyethylene catheter and stainless steel guide wire fragments in the venous vasculature via an incision in the left femoral vein and the remaining group in the arterial vasculature via the left femoral artery. The catheter fragments, made radiopaque by an admixture of 25% lead oxide and 75% polyethylene, were located by roentgenograms and along with the guide wire fragments removed at necropsy 18-46 weeks following implantation. Gross and microscopic tissue lesions consisted of fibrous tissue tubes and slings which completely enclosed and anchored the fragments and intimal hyperplasia with fibrous tissue organization of thrombi, respectively. Tissue staining techniques for lead, catheter fragment weights, blood lead levels, and urine lead content all revealed no evidence of lead loss from the catheter fragment implants.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820070205
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  • 9
    Electronic Resource
    Electronic Resource
    Vulcanization studiesContribution No. 149 from the General Laboratories of the United States Rubber Company. (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 18 (1955), S. 559-562 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Use has been made of the statistical theory of elasticity to calculate the number of crosslinks in vulcanizates that have been formulated and vulcanized in such a manner as to have the greatest number of crosslinks for the amount of sulfur present. These calculations suggest that the formation of up to 80% of the crosslinks are accompanied by the formation of a molecule of sulfide sulfur and that the crosslinks are largely, if not entirely, of the monosulfide type.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120189011
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  • 10
    Electronic Resource
    Electronic Resource
    Chemistry in carbon black dispersionContribution No. 134 from the General Laboratories of U. S. Rubber Co. Presented before the Rubber Division, American Chemical Society, Los Angeles, California. March, 1953. (1954)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 13 (1954), S. 487-498 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Heating rubber-carbon black mixtures at elevated temperatures results in vulcanizates with lower electrical conductivity, lower hysteresis, lower Durometer hardness, and increased abrasion resistance. These changes are apparently the result of chemical reactions between carbon black and rubber which alter the dispersion of the carbon black. Data are presented which show that the basic factors effecting these changes are the chemical reactivities of the carbon black and the polymer and the time and temperature of treatment.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1954.120137109
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