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  • Polymer and Materials Science  (48)
  • Gastric cancer  (2)
  • 61.46.+w  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Einfluß des Vitamin A auf die MNNG-induziert Cancerogenese im Drüsenmagen der Ratte (1983)
    Springer
    Langenbeck's archives of surgery 359 (1983), S. 65-73 
    Details
    ISSN: 1435-2451
    Keywords: Vitamin-A ; Gastric cancer ; Chemical carcinogenesis ; Tumor promotion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In einer Untersuchung an 82 Wistar-Ratten wurden Carcinome des Drüsenmagens mit MNNG erzeugt. Ein Teil der Tiere erhielt zusätzlich hohe Dosen Vitamin A. Wir sahen eine statistisch signifikante Zunahme der Invasionstiefe und damit der Progression des Tumorstadiums unter Vitamin A-Einfluß. Die Häufigkeit des Auftretens von Tumoren war hingegen nicht signifikant verändert. Als Ursache des tumorfördernden Einflußes von Vitamin A in unserem Experiment ist vor allem sein labilisierender Effekt auf celluläre Membransysteme zu diskutieren: 1. Durch Zerstörung lysosomaler Membranen werden Enzyme, Cancerogene und Viren freigesetzt, die direkt oder indirekt zu einer Alteration der DNA führen. 2. Durch Schädigung der Zellmembranen geht die Kontaktinhibition verloren.
    Notes: Summary Carcinomas of the glandular stomach were induced in 82 Wistar rats by means of MNNG1. Part of the group also received high doses of Vitamin A. A consistently significant increase in depth of invasion, i. e. progression of the pathological tumor stage, was observed under the influence of Vitamin A. The frequency of tumor occurrence was not significantly altered. The labilizing effect of Vitamin A on cellular membrane systems is the probable mechanism of Vitamin A's tumor-promoting influence in our experiment: 1. By way of destruction of lysosomal membranes, enzymes, cancerogens, and viruses would be released, leading directly or indirectly to an alteration of the DNA. 2. Damage of cell membranes would lead to loss of the contact inhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254150
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  • 2
    Electronic Resource
    Electronic Resource
    3. Einführung (1982)
    Springer
    Langenbeck's archives of surgery 358 (1982), S. 53-55 
    Details
    ISSN: 1435-2451
    Keywords: Gastric cancer ; Evaluation ; Technique ; Magenkrebs ; Bilanz nach 100 Jahren ; Taktik ; Technik
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Theodor Billroth konzipierte vor 100 Jahren die Technik der Magencarcinom-Resektion und zeitlos gültig die taktischen Prinzipien der radikalen kurativen Krebsoperation am Magen.
    Notes: Summary A hundred years ago Theodor Billroth devised the technique of gastric cancer resection and the perpetually valid tactical principles of radical curative gastric cancer surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01271755
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  • 3
    Electronic Resource
    Electronic Resource
    Crystal and electronic structure of solid C76 (1994)
    Springer
    The European physical journal 95 (1994), S. 469-474 
    Details
    ISSN: 1434-6036
    Keywords: 79.20.Kz ; 61.46.+w ; 61.16.Bg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The crystal and electronic structure of solidC 76 has been studied using transmission electron microscopy and electron energy-loss spectroscopy in transmission. C76 forms a close packed structure with an average facecentred cubic symmetry. From valence band and core electron excitations information on the dielectric function and the unoccupied density of states has been obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01313354
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  • 4
    Electronic Resource
    Electronic Resource
    Interfacial interactions and mechanical properties of filled polymers (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 40 (1990), S. 1783-1794 
    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: Mechanical properties, notably the ductility of rutile-filled low-density polyethylene (LDPE) and chlorinated polyethylene (CPE), were studied to determine the influence of filler dispersion and of matrix-filler interactions. Potential interactions between polymer and filler were obtained from inverse gas chromatography, in the form of acid/base interaction parameters. The strength of filler aggregates was obtained from flow properties of the dry powders. Dispersion quality in molded specimens was identified from X-ray contact micrographs. The ductility of filled, nonpolar LDPE was found to be independent of acid/base considerations, but strong correlations have been drawn between the strength of filler aggregates and the quality of dispersion attained by controlled mixing methods. Inherent filler agglomeration thus also affects the mechanical properties of the nonpolar matrix. Coated, nonagglomerated fillers dispersed well, leading to ductilities at low filler load that exceeded that of the unfilled host polymer. In contrast, acid/base interactions were found to exert dominant influence on rutile dispertion in CPE. Similarly, the mechanical properties of this polymer varied with the acid/base forces acting at matrix/filler contacts.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070400931
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  • 5
    Electronic Resource
    Electronic Resource
    Inverse gas chromatographic study of polymer blend interactions and their temperature dependence (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 787-796 
    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: The temperature dependence of the thermodynamic interactions in blends of polypropylene and a fluorochemical was studied by inverse gas chromatography (IGC). A modified procedure has been proposed to evaluate the effective surface composition in polyblends. This shows that the low surface energy component preferentially concentrates in the surface region of blends. Moreover, the new procedure greatly reduces the probe-to-probe variation of χ23, a problem frequently encountered in thermodynamic applications of the IGC method. As a result, IGC may now be used with increased confidence for the determination of interaction thermodynamics in polymer systems over broad temperature ranges. © 1992 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070460506
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  • 6
    Electronic Resource
    Electronic Resource
    Aspects of surface characterization of polyurethane adhesives (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 1857-1865 
    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: The performances of adhesives is strongly dependent on the contributions to overall surface energies from dispersion and nondispersion forces. In this work, surface energies have been studied for polyurethanes representing the categories of aliphatic and aromatic polyethers and aliphatic polyesters. The surface energies of the polymers were measured by static and dynamic contact angle methods. In addition to determining the energy values for polymers as received, evaluations were also made on the polymers following modification by an aminopropyl silance (APS), present at concentrations ranging from 0.1 to 20 wt %. The dispersion surface energies of the three polymers were roughly equal; however, the nondispersive surface energies strongly differentiated among them. Organic liquids were used for calculations of energy parameters from static contact angles. Data for water failed to follow theoretical expectations and were used instead to compute a work of adhesion parameter for the polymer/water interface. This correlated with nondispersion surface energies of the polyurethanes. Somewhat different values of the nondispersion surface energy were obtained from static and dynamic contact angles, an effect attributed to the tendency of polyurethanes to restructure when their surfaces were in prolonged contact with water during dynamic analysis. This behavior may be important to the type of adhesive bond formed by the polymers and to variations in bond characterstics with time. The use of APS was found to influence both static and dynamic contact angle values, with primary changes occuring in nondispersion contributions. The effects of APS addition were fully developed at concentrations of 1 wt % or less, raising doubts about the efficiency of using this additive at higher concentrations. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070521303
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  • 7
    Electronic Resource
    Electronic Resource
    Crosslinking reactions in pigmented olefinic polymers (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 2049-2054 
    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: Thermally initiated crosslinking reactions have been studied in a linear low-density polyethylene, and an ethylene - propylene rubber. The polymers contained conventional thermal stabilizers or one of three surface-coated rutile pigments. Enthalpies of crosslinking and reaction kinetics depended on the degree of terminal vinyl unsaturation in the polymers, that characteristic being greater in the rubber than in the polyethylene. The presence of thermal stabilizers did not exert any measurable influence on measured parameters of the crosslinking processes. The effects of rutile varied, depending on their surface acidity or basicity, as determined from chromatographic measurements. Basic rutile was found to reduce heats and to slow rates of reaction, while acidic rutiles did not affect the reactions. These observations may be attributed to interaction between the basic pigment surface and acidic moieties involved in the crosslinking reaction. © 1992 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070461118
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  • 8
    Electronic Resource
    Electronic Resource
    Surface characteristics of polymer/small molecule blends (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 743-752 
    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: Inverse gas chromatographic data have been obtained for polystyrene, polycarbonate, and two substituted amines used as additives in the polymers. Surface energies have been determined and evaluations made of acid/base interaction parameters and Flory-Huggins χ values for the surface bounded interphase. It was shown that acid/base considerations are implicated in the miscibility of these polymer/additive systems. Surface energy analyses showed that surface and bulk compositions in blends differed whether or not the blend components were miscible. Composition differences were the result of thermodynamic drives to minimize surface free energy. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070540605
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  • 9
    Electronic Resource
    Electronic Resource
    Assessment of degree of fusion of rigid PVC from inverse gas chromatographic measurements (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 51-56 
    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: Inverse gas chromatography of alkanes has been used to assess the degree of fusion of rigid polyvinyl chloride (PVC) extrudates. The relative degree of fusion is provided by ratios of the retention volumes of the alkane probe molecules in the bulk of the PVC. This method is nonintrusive and can be used to measure degree of fusion quantitatively if a completely fused reference material can be provided. The present analysis involves evaluations of the contributions to the overall retention volume of the alkane probes, resulting from adsorption and from bulk diffusion. The diffusivity of the alkanes was clearly dependent on the processing history of the PVC extrudate. A direct variation was observed between the size of the diffusing molecules and their residence time as adsorbates on the polymer surface. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070560107
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of polyolefins by solution DTA (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 539-543 
    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
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160223
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