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  • 1975-1979  (11)
  • 1905-1909  (3)
  • Chemistry  (9)
  • Life and Medical Sciences  (3)
  • synergism  (2)
  • Allelopathy
  • Biochemistry and Biotechnology
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 3 (1977), S. 197-205 
    ISSN: 1573-1561
    Keywords: synergism ; ferulic acid ; p-coumaric acid ; allelopathy ; phytotoxicity ; inhibition ; sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The data support the hypothesis that there is a synergistic phytotoxic effect whenp-coumaric and ferulic acids are found together. Equimolar mixtures of both acids showed greater reduction in sorghum seed germination, shoot elongation, and total seedling growth than either phytotoxin caused when alone. Repeated experiments showed mixtures containing 5×10−3 Mp-coumaric and 5×10−3 M ferulic acids reduced germination to 34% of controls after 24 hr and 59% by 48 hr. The same concentration of either phenol-treated seeds alone showed 69 and 92% germination at comparable times. The phytotoxic action of the combination approximated the inhibitory effect on germination of 10−2 M ferulic acid and was a greater reduction than caused by 10−2 Mp-coumaric treatments. Sorghum seedling growth was more sensitive than germination, with an equimolar mixture of 2.5×10−4 Mp-coumaric and 2.5×10−4 M ferulic acids reducing seedling dry weight significantly below weights of seedlings treated separately with 2.5×10−4 Mp-coumaric or ferulic acids. Further dilutions showed a 1.25×10−4 M concentration of either phenol was stimulatory to seedling growth, whereas a mixture of these two produced inhibition.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 4 (1978), S. 425-436 
    ISSN: 1573-1561
    Keywords: synergism ; vanillic acid ; p-hydroxybenzoic acid ; allelopathy ; inhibition ; sorghum ; radish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Radish and grain sorghum germination and sorghum growth were inhibited in a synergistic manner by combinations of vanillic andp-hydroxybenzoic acids. At threshold inhibition levels, 2.5 × 10−3 M vanillic acid-treated radish seeds had 71 % of control germination after 24 hr and 2.5 × 10−3 Mp-hydroxybenzoic acid-treated radish yielded 95% germination. A mixture of 2.5 × 10−3 M of each of these two phytotoxins showed 52% germination after 24 hr. Equimolar mixtures of 5 × 10−3 M vanillic andp-hydroxybenzoic acids allowed sorghum germination of 60% of untreated seeds after 24 hr, whereas separate treatments of individual phenols had 93% and 96% of control seed germination. Sorghum root and shoot elongation and total seedling growth were more sensitive than germination to vanillic andp-hydroxybenzoic acid treatments, and synergistic effects also were apparent. A combination of 5 × 10−3 M vanillic with 5 × 10−3 Mp-hydroxybenzoic reduced root length more than either did individually, and a mixture of 5 × 10−4 M vanillic with 5 × 10−4 Mp-hydroxybenzoic acid reduced sorghum seedling growth to approximately that resulting from a 10−3 M concentration of either phenol alone. Phytotoxin levels inhibitory to sorghum growth caused small increases in lower leaf surface diffusive resistance, but did not close stomates, and this effect was not judged to be the cause of reduced sorghum growth.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 1 (1975), S. 227-234 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: IR-spektroskopische Untersuchungen von Polyäthylen-Proben, dargestellt durch Reduktion von Polyvinylchlorid mit Lithiumaluminiumhydrid, ließen darauf schließen, daß Polyvinylchlorid Seitenketten enthält, die seine Morphologie und Festkörpereigenschaften wesentlich beeinflussen. Die Natur dieser Seitenketten war bisher unbekannt. Es wird anhand von 13C-NMR Spektren gezeigt, daß die Verzweigungen in reduziertem Polyvinylchlorid aus Methylgruppen bestehen, die vermutlich aus Chlormethylgruppen des ursprünglichen Polymeren entstanden sind. Die untersuchte Probe enthielt ca. 3 CH3-Gruppen pro 1000 CH2-Gruppen, jedoch is dieses Verhältnis vermutlich von der Polymerisationstemperatur abhängig. Zusätzlich wurden Anzeichen für längere Seitenketten gefunden, die allerdings nur in einem Ausmaß von weniger als 1 pro 1000 CH2-Gruppen vorhanden sein dürften.
    Notes: The presence of branches in poly(vinyl chloride) as indicated by previous IR measurements on the polymer reduced to polyethylene by means of lithium aluminum hydride is believed to affect materially the morphology and solid state properties of poly(vinyl chloride); however, up to the present, the nature of these branches has not been known. By use of 13C-NMR on reduced poly(vinyl chloride) it is demonstrated that the brances are methyl groups, presumably corresponding to chloromethyl groups in the original polymer. In the sample studied, the frequency is ca. 3 methyl groups per 1000 CH2 groups, but this is expected to depend on the temperature of polymerization. There is also some evidence for long branches, probably not exceeding 1 per 1000 CH2 groups.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Described herein are proton nmr experiments on chemically modified derivatives of ribonuclease A designed to elucidate the origin of an exchangeable resonance, assigned previously to a histidine ring N proton that titrates between 11 to 13 ppm with a pKa of 6.1 in H2O solution. Histidines 48 and 105, which are distant from the active site, are eliminated as candidates for this resonance from inhibitor binding studies on the enzyme in acetate-water solutions. This exchangeable resonance titrates with modified pKa's and constant area over the above pH range in His-119-N1-carboxymethylated-RNase A and des-(121-124)-RNase A, thus eliminating the imidazole N3 proton in the His 119-Asp 121 hydrogen bond. In His-12-N1-carboxymethylated-RNase A, this resonance is also observable, but broadens on raising the pH above 7 and at elevated temperatures above neutrality. It exhibits a pH-independent chemical shift characteristic of the protonated state of histidine. On the basis of these findings, this exchangeable resonance, designated a, is assigned to the imidazole N1 proton of His 12, which is hydrogen-bonded to the carbonyl oxygen of Thr 45 in the crystal.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 987-997 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The C2H resonance of the active site histidine residue designated AS-2, which has the lower pKa of the two active site histidines, has been correlated in both RNase A and RNase S by comparing the pH 3 to 5.5 regions of the chemical shift titration curves, the effect of the inhibitor CMP-3′ on the chemical shifts at pH 4.0, and the effect of Cu II on the line widths at pH 3.6. It has been demonstrated that resonance AS-2 is absent in the spectrum of RNase S′ reconstituted using S-peptide deuterated at the C2 of His 12, and in that of the RNase S′-CMP-3′ complex. We thus demonstrate that histidine AS-2 is in fact His 12 in both enzymes. This finding is in agreement with out previous assignment of the exchangeable NH proton in RNase A to His 12, but reverses the assignments of the active site histidine C2H resonances made earlier by other authors.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 193 (1979), S. 383-387 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Regeneration of the rat kidney was observed for six days after inducing acute tubular necrosis of the proximal pars recta with d-serine (80 mg/100g body weight). Regenerating cells appear by two days post-treatment, and re-epithelialization of the nephron is completed within six days, with the most mature cells approaching normal morphology. Regeneration originates from viable cells adjacent to the necrotic zone which divide and follow a template provided by the intact basement membrane. Transient, cytoplasmic regenerative activity among developing tubular cells is characterized by the presence of large, irregularly shaped nuclei, prominent nucleoli, abundant ribosomes and lysosomes, and abnormal mitochondrial configurations. Microfilaments appear to be involved in the formation of apical microvilli and the basal labyrinth of plasmalemmal convolutions. These data suggest that d-serine. inducedacute tubular necrosis of the proximal pars recta may be followed by rapid, patterned regeneration along an intact basement membrane, and that microfilaments are involved in differentiation of cellular morphology.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 155 (1979), S. 375-389 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ileum from rats 4, 9, 11, 12, and 15 days old can best be maintained for 24 hours in a system using Hanks' Balanced Salt Solution without fetal calf serum, at 25°C and 21% O2. Suckling rat duodenum and jejunum were difficult to maintain well for 24 hours in this system or a variety of other systems that were tried. A temperature of 37°C hastened deterioration of duodenum, jejunum or ileum. With ileum, 3H-thymidine and 14C-leucine were increasingly incorporated into DNA and protein over the 24-hour period. Light microscopy, as well as scanning and transmission electron microscopy, showed very good preservation of the ileum after 24 hours. The addition to the medium of hydrocortisone, 1 μm, and thyroxine, 0.01 μm, alone or in combination, did not change DNA or protein synthesis, or morphology, possibly because of the relatively short (24 hour) time period. Our organ culture system emphasizes the differences between suckling rat ileum and the rest of the intestine, and provides a new tool for evaluating, over a 24-hour period, the developing rat small intestine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 4 (1905), S. 453-485 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 12 (1979), S. 362-364 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 251 MHz 1H and the natural-abundance 63.1 MHz 13C NMR spectra of N,N'-dimethylimidazolidine have been measured from -50 to -170°C. Below about -140°C. nitrogen inversion in the compound becomes slow on the NMR time scale and both the 1H and the 13C spectra indicate that it exists in solution as a mixture of cis and trans conformations having nearly the same energies. The free-energy barrier (ΔG≠) for nitrogen inversion in N,N'-dimethylimidazolidine is 6.4 kcal mol-1, a value which is 1.5 kcal mol-1 lower than that for N-methylpyrrolidine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 8 (1976), S. 327-328 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C n.m.r. chemical shifts of the sp-hybridized carbons in dialkylcarbodiimides have values of δc ≃ 140. These shifts are compared with those of similarly hybridized carbons occuring in other classes of compounds.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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