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  • Digitale Medien  (18)
  • Chemistry  (14)
  • Inorganic Chemistry  (4)
  • Asparagus  (2)
  • DNA break  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Gene Structure and Expression 698 (1982), S. 40-48 
    ISSN: 0167-4781
    Schlagwort(e): (Human fibroblast) ; DNA break ; DNA damage ; DNA repair ; Gamma irradiation ; Retinoblastoma
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie , Medizin , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Gene Structure and Expression 698 (1982), S. 40-48 
    ISSN: 0167-4781
    Schlagwort(e): (Human fibroblast) ; DNA break ; DNA damage ; DNA repair ; Gamma irradiation ; Retinoblastoma
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie , Medizin , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Plant foods for human nutrition 49 (1996), S. 13-26 
    ISSN: 1573-9104
    Schlagwort(e): Asparagus ; Ripening ; Minerals ; Calcium ; Magnesium ; Sodium ; Potassium and phosphorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The essential elements: calcium (Ca), magnesium (Mg), sodium (Na) potassium (K) and phosphorus (P) were analyzed in fresh asparagus to determine the effect of the ripening of the asparagus on the mineral content. Asparagus samples were classified in two groups by diameter (〈11 mm and 〉14 mm). Asparagus from a sample group with the same diameter were divided into two portions (apical and basal) according to distance from the tip. The concentrations of calcium, magnesium and phosphorus increased with the ripening process of the asparagus while the content of sodium decreased when the white asparagus turned into a green ripening state. No significant differences were established for potassium. The green ripening state was the group with the greater concentration of calcium, magnesium and phosphorus. Statistically significant differences (p〈0.001) were observed between portions of asparagus (tip and rest of stem) in the contents of the five mineral elements analyzed. The levels of mineral elements investigated increased notably in the tip of the asparagus with the exception of sodium and potassium of which the levels in the apical portion decreased or hardly modified. The variance analyses determined statistically significant differences (p〈0.001) in the concentration of magnesium, sodium and phosphorus between asparagus diameters (〈11 and 〉14 mm) and no significant differences (p〉0.05) were found for calcium and potassium. The mean element levels were (mg/kg dry weight): Ca=3240±1186; Mg=1818±490; Na=368±86; K=37297±4167 and P=6809±2491.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1573-9104
    Schlagwort(e): Asparagus ; Copper ; Iron ; Manganese ; Vegetative cycle ; Zinc
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The essential elements copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) were analyzed in fresh asparagus to determine the effects of the vegetative cycle of the plant on the micronutrient content. Asparagus samples were classified in two groups by diameter (〈11 mm and 〉14 mm). Asparagus from a sample group with the same diameter were divided into two portions (apical and basal) according to distance from the tip. The concentrations of copper, iron, zinc and maganese increased during the vegetative cycle of the asparagus, mainly in the apical portion which showed significantly greater concentrations with respect to the basal portion. The 〉14 mm diameter asparagus presented higher levels of copper, zinc and manganese, whereas the concentration of iron was greater in the 〈11 mm diameter asparagus. The mean element levels were (mg/kg dry weight): Cu, 18.9±3.9; Fe, 91.7±33.7; Zn, 69.5±24.6 and Mn, 20.9±5.0).
    Materialart: Digitale Medien
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  • 5
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The configuration of several keto-cyclolignans related to podophyllotoxin has been reviewed. Under basic catalysis, the configuration at the C-atom in α-position to the lactone carbonyl group in podophyllotoxone is inverted instead of the C-atom in α-position to the ketone group, as it has been reported.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 27 (1989), S. 709-722 
    ISSN: 0887-6266
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The thermal and dielectric behaviors of poly(vinylidene fluoride-trifluoroethylene) copolymers near the ferroelectric-to-paraelectric phase transition are investigated for samples with 20, 25, 30, and 40 mol% trifluoroethylene (TrFE). The data suggest that the transition becomes continuous for a particular composition near 50 mol% TrFE. Experimental data are sensitive to thermal history (kinetics of crystallization, and kinetics and cycling over the structural transition). It is found that several anomalies are present at the structural change, and in particular the 30 mol% TrFE sample shows the most marked anomalies. These phenomena can be attributed to defects, but another possibility would be the existence of an intemediate supplementary phase. Both hypotheses are discussed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 767-778 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: An analysis of the diffusion of oxygen and carbon dioxide through linear low density polyethylene (LLDPE) subjected to longitudinal and transversal induced stretching in the ratio 2:1, is presented in this paper. The relaxation behavior of two coextruded LLDPE films prepared from copolymers of ethylene-1-octene is reported as well. The spectra, expressed in terms of loss tan δ, present a γ relaxation shifted 5°C to 10°C in the LLDPE1 with respect to the LLDPE2 when the stretching was longitudinal. This relaxation is lower in intensity than the one exhibited for conventional low-density polyethylene of the same crystallinity. Increasing the temperature order, a β relaxation process appears as an ostensible shoulder of the first of two relaxation processes, called α′ and α″, detected in the α region. The β relaxation, which is believed to be produced by motion taking place in the amorphous and interfacial regions, appears as two overlapping peaks centered at -36°C and -30°C for a longitudinal stretching and at -34°C and -28°C for a transversal stretching at 1 Hz. In relation to this fact, we observed a slight increase in the Tα of the LLDPE2 with respect to the LLDPE1, which is greater in the transversally stretched polymers than in the longitudinal ones. The values of the activation energy corresponding to the second peak of the β relaxation were obtained for the films subjected to stretching in longitudinal and transversal directions to the processing orientation. The study of the diffusional characteristics of oxygen and carbon dioxide through the films shows the temperature is related to the region for which the α processes are given. An anomalous behavior of the diffusion coefficient with the temperature is observed, suggesting general movements around the amorphous segments and crystalline entities. The increase with the temperature of both parameters (diffusion and permeability) can be attributed to a change in the gas solubility. This increase is greater for CO2 than for O2 which we interpret as a plastificant effect of the CO2. Finally, the activation energies from diffusion coefficent and permeability are analyzed in terms of Arrhenius. The results show that the temperature dependence of the diffusive parameters may not be a simply activated process as a consequence of the fact that the diffusional characteristics of the films depend on their morphology which, in turn, is changing with temperature. Little changes are observed when the films are subjected to any kind of stretching. In this sense, we think that the orientation by tensile drawing will decrease the conformational entropy involved in melting processes and, as a consequence, will reduce both the permeability and the apparent diffusion coefficients. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 31 (1996), S. 313-317 
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: In this work the corrosion behavior of a new biomaterial, the MA-956 superalloy, immersed in Hank's solution is evaluated. A comparison with conventional metallic alloys used as articular implants is established. To determine the corrosion behavior we employed electrochemical methods: evaluation of corrosion potential Ecorr, electrochemical impedance spectroscopy (EIS), and anodic polarization curves. The corrosion resistance of the MA-956 superalloy preoxidized at 1100°C during 100 h is at least two orders of magnitude higher than for the other alloys. This satisfactory behavior is stationary with time. Also the probability of the appearance of the pitting corrosion process is very low. When cracking is generated in the α-alumina layer the repassivation process is assured because of the high Cr content in the superalloy. This study is the first step in proposing this new alloy as a biomaterial. The low toxicity of these metallic alloys in the physiological environment suggests that in vivo their biocompatibility could be satisfactory. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 737-742 
    ISSN: 0170-2041
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Synthese von Pyrimidin-Analoga des Nucleosid-Antibiotikums AscamycinVier Analoga des Ascamycins 〈5′-O′-O-[N-(L-alanyl)sulfamoyl]-2-chloradenosin〉(1), bei welchen der 2-Chloradenosinrest durch Uridin, Thymidin, Cytidin und 2′-Deoxy-5-methylcytidin ersetzt wurde, sind durch selektive Aminoacylierung der 5′-O-Sulfamoyl-Derivate 2, 9, 14 und 21 des 2′,3′-Di-O-acetyluridins, 3′-O-Acetylthymidins, 2′,3′-O-Isopropylidencytidins, bzw. des 3′-O-Acetyl-2′-deoxy-5-methylcytidins mit Boc-L-Ala-OSu in DMF und in Anwesenheit von DBU, mit nachfolgender Abspaltung der Schutzgruppen, erhalten worden. Ähnlich wurde 5′-O-[N-(D-Alanyl)sulfamoyl]uridin (8) ausgehend von Boc-D-Ala-OSu und 2 hergestellt. Die Verbindungen 14 und 21 wurden direkt durch Sulfamoylierung der 4-N-(Dimethylamino)methylen-Derivate 13 und 20 von 2′,3′-O-Isopropylidencytidin bzw. 3′-O-Acetyl-2′-deoxy-5-methylcytidin über die 5′-O-Tributylzinn-Zwischenverbindungen dargestellt. Verbindung 20 wurde aus 5′-O-Isopropylidencytidin bzw. 3′-O-Acetyl-2′-deoxy-5-methylcytidin über die 5′-O-Tributylzinn-Zwischenverbindungen dargestellt. Verbindung 20 wurde aus 5′-O-(tert-Bu-tyldimethylsilyl)thymidin (17) mittels Acetylierung und nachfolgende Überführung des Thymidinrestes in 5-Methylcytosin über das entsprechende Triazolylpyrimidinon unter Schutz der Amidingruppe erhalten.
    Notizen: Four analogues of ascamycin 〈5′-O-[N-(L-alanyl)sulfamoyl]-2-chloroadenosine〉 (1) in which the 2-chloroadenosine moiety has been replaced by uridine, thymidine, cytidine, and 2′-deoxy-5-methylcytidine have been synthesized by selective aminoacylation of the 5′-O-sulfamoyl derivatives 2, 9, 14, and 21 of 2′,3′-di-O-acetyluridine, 3′-O-acetylthymidine, 2′,3′-O-isopropylidenecytidine, and 3′-O-acetyl-2′-deoxy-5-methylcytidine, respectively, with Boc-L-Ala-OSu in DMF and in the presence of DBU, followed by removal of the protecting groups. Similarly, 5′-O-[N-(D-alanyl)sulfamoyl]uridine (8) has been prepared from Boc-D-Ala-OSu and 2. Compounds 14 and 21 were directly prepared by sulfamoylation of the 4-N-(dimethylamino)methylene derivatives 13 and 20 of 2′,3′-O-isopropylidenecytidine and 3′-O-acetyl-2′-deoxy-5-methylcytidine, respectively, via the intermediate 5′-O-tributyltin derivatives. Compound 20 was obtained from 5′-O-(tert-butyldimethylsilyl)thymidine (17) by a route involving acetylation, conversion of the thymidine moiety into 5-methylcytosine through the corresponding triazolylpyrimidinone, and amidine protection.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 61 (1997), S. 613-626 
    ISSN: 0020-7608
    Schlagwort(e): Chemistry ; Theoretical, Physical and Computational Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The energy of the vibrational mode with spherical symmetry, in which the ionic cores oscillate in the radial direction around the equilibrium geometry (ionic breathing mode) is calculated for trivalent (AlN, 2≤N≤50) and monovalent (NaN, 2≤N≤73; CsN, 2≤N≤74) metallic clusters. The ground-state total energy is calculated using density functional theory, with a spherically averaged pseudopotential to describe the ion-electron interaction and optimizing the geometry by the simulated annealing technique. The energy of the ionic mode is calculated by diagonalization of the dynamical matrix including the electronic relaxation in the linear response approximation. The compressibility and bulk modulus of the metallic cluster are obtained from the energies of the monopole oscillations. These energies present a linear behavior on the inverse of the cluster radius, which is analyzed using a semiclassical liquid drop mass formula for the total energy of the clusters and a scaling model. The values of the vibrational frequencies present electronic shell closing effects for the three metals.©1997 John Wiley & Sons, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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