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  • Polymer and Materials Science  (17)
  • Engineering  (5)
  • Fe-Versorgung  (2)
  • 1
    ISSN: 1436-6215
    Keywords: Fe-Versorgung ; Proteinversorgung ; Fe-Protein-Wechselwirkung ; Fe-Konzentration in verschiedenen Organen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary In a 2×3factorial experiment with growing rats the diet varied for the iron content (5, 25, 625 ppm) and for the protein content (5, 25, 45 %). The diets were fed ad libitum for 35 days. At the end of the experiment the iron content of different organs was determined. Both experimental factors and their interactions influenced the iron concentration as well as fresh weight and dry matter dependent on organ. Especially the influence of deficient protein supply and of insufficient iron supply was very marked. Dependent on the iron supply there are different responses between storage and functional compounds of iron.
    Notes: Zusammenfassung In einem 2×3faktoriellen Versuch mit wachsenden Ratten variierte der Fe-Gehalt der Diät in drei Stufen (5, 25, 625 ppm) und der Proteingehalt ebenfalls in drei Stufen (5, 25, 45 %). Die Diäten wurden den Versuchstieren 35 Tage ad libitum verfüttert und nach Versuchsende der Fe-Gehalt in verschiedenen Organen bestimmt. Die beiden Versuchsfaktoren und deren Wechselwirkungen beeinflußten die Fe-Konzentration sowie Frischgewicht und Trockensubstanzgehalt je nach Organ. Besonders starken Einfluß übten sowohl eine mangelhafte Proteinzufuhr als auch eine nicht bedarfsgerechte Fe-Versorgung aus. In Abhängigkeit von der Fe-Versorgung zeigten sich zwischen Speicherverbindungen und funktionellen Verbindungen für Eisen unterschiedliche Reaktionen.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 23 (1984), S. 20-30 
    ISSN: 1436-6215
    Keywords: Cu-Versorgung ; Fe-Versorgung ; Cu-Fe-Wechselwirkungen ; Cu-Fe-Gehalte in Organen und Geweben
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary The Fe and Cu contents in the femur and in the skeleton muscle were investigated in a trial series with factorial Fe and Cu supplies of growing rats (0, 25, 250, and 625 μg of Fe supply; 0, 10, 100, and 250 μg Cu supply per g of the diet). In addition, the reaction of the carcass to the different trace element supply was compared to the changes of the Fe and Cu contents in organs and tissues. In the femur, the Fe contents clearly increase in all grades of the Cu supply with increasing Fe supply. But because of the reduced live weight of the trial animals without Fe supply, this is valid only from 25 μg Fe/g diet on. For all Fe levels, the influence of the Cu supply on the concentration and the content of Cu results in a plateau in the range of 10–100 μg Cu/g diet; it is not reached with Cu deficiency and exceeded with an excessive Cu supply (250 μg/g). A clear increase of the Fe concentration in the muscle occurs only at a supply of 250 μg Fe/g diet. A further increase at 625 μg Fe/g only occurs at a Cu supply of 250 μg/g. Generally, the Fe concentration is reduced in the Cu deficiency. The Cu concentration in the muscle increases in all cases with the Cu supply, and the extent of this increase is strongly influenced by the Fe supply. The Fe contents in the carcass primarily depend on the Fe dosage. For the total contents of copper there are hints of a homeostatical regulation in the range of 10–100 μg Cu/g, but it seems to be disturbed if the Fe supply (0 or 25 μg/g) is insufficient. The comparison of the Fe and Cu contents in organs and tissues to those in the carcass shows that the reactions to the different supply levels, which are clearly different in the tissues, can be reproduced but insufficiently by the trace element analysis in the carcass.
    Notes: Zusammenfassung Im Rahmen einer Versuchsreihe mit faktorieller Fe- und Cu-Versorgung wachsender Ratten (0, 25, 250 und 625 μg Fe-Zulage; 0, 10, 100 und 250 μg Cu-Zulage je g Diät) wurden die Fe- und Cu-Gehalte im Femur und Skelettmuskel untersucht. Zusätzlich wurde die Reaktion des Ganzkörpers auf die unterschiedliche Spurenelementzufuhr mit der Veränderung des Fe- und Cu-Gehaltes in Organen und Geweben verglichen. Im Femur steigen die Gehalte an Eisen bei allen Stufen der Cu-Versorgung deutlich mit der Fe-Zufuhr an. Bedingt durch die verringerte Lebendmasse der Versuchstiere ohne Fe-Zulage gilt dieser Zusammenhang erst ab 25 μg Fe/g Diät. Der Einfluß der Cu-Versorgung auf die Konzentration und den Gehalt an Kupfer ergibt für alle Fe-Stufen ein Plateau im Bereich von 10–100 μg Cu/g Diät, das bei Cu-Mangel in der Regel unter-, bei exzessiver Cu-Zufuhr (250 μg/g) überschritten wird. Im Muskel erfolgt ein deutlicher Anstieg der Fe-Konzentration erst bei einer Zufuhr von 250 μg Fe/g Diät. Durch 625 μg Fe/g tritt nur bei einer Cu-Zulage von 250 μg/g eine weitere Erhöhung auf. Im Cu-Mangel ist die Fe-Konzentration in der Regel erniedrigt. Die Cu-Konzentration im Muskel steigt in allen Fällen mit der Cu-Zufuhr an, wobei das Ausmaß dieses Anstiegs stark durch die Fe-Versorgung beeinflußt wird. Die Fe-Gehalte im Ganzkörper sind in erster Linie von der Fe-Dosierung abhängig. Für die Gesamtgehalte an Kupfer ergeben sich im Bereich von 10–100 μg Cu/g Hinweise auf eine homöostatische Regulation, die aber bei unzureichender Fe-Zufuhr (0 bzw. 25 μg/g) offensichtlich gestört ist. Der Vergleich der Fe- und Cu-Gehalte in Organen und Geweben mit denen im Gesamtkörper zeigt, daß die in einzelnen Geweben deutlich unterschiedlichen Reaktionen auf die einzelnen Versorgungsstufen durch die Spurenelementbestimmung im Ganzkörper nur sehr begrenzt wiedergegeben werden.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 3187-3199 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Previous attempts to prepare monodisperse styrene/sodium styrene sulfonate copolymer latexes by batch, seeded, and semicontinuous emulsion polymerization were unsuccessful at high concentrations of the functional comonomer. Broad, and sometimes bimodal, size distributions, and large amounts of water soluble homopolymer were obtained. After removal of free monomer, solute and adsorbed homopolymer and copolymer, the overall incorporation of the functional comonomer was found to be low. To overcome these problems, a two stage “shot-growth” or in situ seeding technique was developed. A first stage copolymerization was carried out with a low concentration of sodium styrene sulfonate: the purpose of the functional comonomer was to enhance the stability and regulate the size of the seed particles. When this reaction had reached high conversion (〉 90%), a second stage monomer mixture was added. The ratio of styrene to sodium styrene sulfonate in this mixture determined the final surface charge density. The mechanism by which the NaSS is incorporated in the polymer particles is considered to be by solution copolymerization with solute styrene monomer to form surface active oligoradicals. These radicals adsorb on the particle surface, initiate polymerization and become inextricably bound, preventing their transfer back to the aqueous phase. By this means, it was possible to vary independently the particle size and surface charge density. High concentrations of functional comonomer could be polymerized without undue wastage (incorporations were only slightly less than 100%) or loss of monodispersity. In extreme cases, the area per functional group fell below the theoretical minimum, indicating considerable hydration of the surface layers.
    Additional Material: 6 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2865-2872 
    ISSN: 0887-624X
    Keywords: alkali-soluble random copolymer ; polymeric emulsifier ; aggregate ; hairy ASR layer ; rate of polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An alkali-soluble random copolymer (ASR), poly(styrene/α-methylstyrene/acrylic acid), was used as a polymeric emulsifier in the emulsion polymerization of styrene. The calorimetric technique was applied to study the kinetics of emulsion polymerization of styrene using ASR and a conventional ionic emulsifier, sodium dodecyl benzenesulfonate (SDBS). ASR could form aggregates like micelles, and the solubilization ability of the aggregates was dependent on the neutralization degree of ASR. The rate of polymerization in the ASR system was lower than that in the SDBS system. This result can be explained by the creation of a hairy ASR layer around the particle surface, which decreases the diffusion rate of free radicals through this region. Although a decrease in particle size was observed, the rate of polymerization decreased with increasing ASR concentration. The higher the concentration of ASR is, the thicker and denser ASR layer may be, and the more difficult it would therefore be for radicals to reach the particle through this layer of ASR. The rate of polymerization decreased with increasing the neutralization degree of ASR. The aggregates with high neutralization of ASR are less efficient in solubilizing the monomer and capturing initiator radicals than that of the lower neutralization degree, which leads to decrease in rate of polymerization. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2865-2872, 1998
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 171-183 
    ISSN: 0887-624X
    Keywords: latex ; sulfonate functional groups ; poly(styrene-sodium styrene sulfonate) ; emulsion copolymerization ; emulsifier-free ; enhanced gel effect ; ion association ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the emulsifier-free emulsion copolymerization of styrene and sodium styrene sulfonate have been examined over a range of comonomer compositions. The rate of polymerization was found to increase dramatically in the presence of small amounts of sodium styrene sulfonate. This increase is attributed to the increased number of particles formed when sodium styrene sulfonate was present and to a gel effect enhanced by ion association. At low concentrations of functional comonomer, where a monodisperse product was obtained, a homogeneous nucleation mechanism of particle generation is proposed. At higher concentrations, broader and then bimodal size distributions were obtained, and this is ascribed to significant aqueous phase polymerization of sodium styrene sulfonate. The water-soluble homopolymer is supposed to act as a locus of polymerization. The occurrence of this aqueous phase side reaction and the generation of secondary particles makes impossible the preparation of highly sulfonated polystyrene latexes by batch or seeded batch emulsion copolymerization.
    Additional Material: 12 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 721-730 
    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: Homo- and copolymerization of ethylene were performed by using a catalyst system composed of TiCl4/THF/MgCl2 complex activated with AlEt3 at 70°C and 3 atm. To investigate the effect of the compositional difference of the catalyst on the rates of homo- and copolymerization and on the reactivity in ethylene-hexene copolymerization, a series of six catalysts with different compositions (Mg/Ti = 0.4-16.5) were prepared by coprecipitation. The catalytic activity in ethylene polymerization increased sharply with the Mg/Ti ratio from 21 (Mg/Ti = 0.4) to 1477 kg PE/g-Ti h (Mg/Ti = 16.5). The activity in copolymerization with 1-hexene also increased with Mg/Ti ratio. The values of r1 were 120, regardless of Mg/Ti ratios within the experimental error range. Enhancement of the polymerization rate by the addition of 1-hexene in the reaction medium was observed only for the catalysts of low Mg/Ti ratio. This unusual effect of 1-hexene on the polymerization rate was explained by chemical and physical processes that occurred during polymerization. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1647-1652 
    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 equilibrium uptake of o-phenyl phenol onto Courtelle S at 98°C was found to follow a Nernst adsorption mechanism, indicating that uptake arises by virtue of hydrophobic interaction as well as ion-dipole, dipole-dipole, and dipole-induced dipole forces operating between the fiber and the nonionic carrier. Differential scanning calorimetry was used to demonstrate the plasticizing action of the carrier on Courtelle S yarn. A linear relationship was obtained between the extent of plasticization, as measured by reduction in Tg of the fiber, and concentration of carrier applied to the fiber with the maximum extent of plasticization, showing a close correspondence to the aqueous solubility of o-phenyl phenol at 98°C, the temperature at which the fiber was treated with the carrier. The relationship between the extent of enhancement of uptake of C. I. Basic Green 4 and C. I. Basic Red 13 onto Courtelle S yarn at 98°C and concentration of the carrier in the dyebath was also examined: The concentration of o-phenyl phenol that gave maximum enhancement of dye uptake coincided with the aqueous solubility of the carrier at 98°C. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 8
    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: Composite reverse osmosis membranes of ionically crosslinked poly(acrylic acid) (PAA) have been prepared. The process consists of coating a porous polysulfone membrane with a thin layer of dilute solution of PAA, drying the thin liquid layer, and ionically crosslinking the PAA in solutions of different salts. The influence of some important preparation parameters on the properties of these membranes was investigated. It was found that all these membranes possessed ion exchange properties and could be ion exchanged; some of them have been found to be suitable for the desalination of low concentration salt solutions. By comparison to cellulose acetate (CA) membranes, higher rejection of phenols may be an interesting property of these membranes.
    Additional Material: 7 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 4017-4027 
    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 synthesis of sulfonated poly(phenylene oxide) polymer was investigated. The poly(phenylene oxide) was synthesized through oxidative coupling from 2,6-dimethyl-phenol with copper (I) chloride-pyridine catalyst and sulfonated using chlorosulfonic acid. The effects of catalyst concentration, solvent, and other experimental variables on the kinetics of the polymerization of poly(phenylene oxide) and its subsequent sulfonation are reported in detail.
    Additional Material: 7 Ill.
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  • 10
    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: Thin film composite membranes of sulfonated poly(phenylene oxide) (SPPO)-polysulfone (PS) (SPPO-PS) were prepared by coating the hydrogen or sodium form of SPPO onto various porous substrates such as polysulfone (PS). The effects of membrane preparation conditions and feed water variables on the salt rejection and production rates were investigated using reverse osmosis. Purification of the waste waters from the Alberta heavy oil fields for desalination and recycling use was carried out. Production rates and salt rejections for the various feeds were found to be in the range of 5-20 gfd (gallons/ft2 day) and 80-99% respectively at 600 psig and 20°C, depending on the experimental conditions and membrane properties.
    Additional Material: 3 Ill.
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