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  • 1
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Extensive networks of metastable ions link the major peaks in the electron impact mass spectra of two crown ethers containing 2,6-pyrido units. High-resolution mass measurements and the metastable peaks allow the elucidation of the fragmentation pathways. The spectra are influenced more by the presence of aromatic substituents than by the 2,6-pyrido units.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    FEBS Letters 161 (1983), S. 217-220 
    ISSN: 0014-5793
    Schlagwort(e): Chromatin ; DNA ; Human leukemia ; Restriction endonuclease digestion
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Mechanisms of Ageing and Development 34 (1986), S. 57-61 
    ISSN: 0047-6374
    Schlagwort(e): Barley leaves ; Chromatin ; DNA ; Senescence
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 618-621 
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Negative-ion continuous-flow fast-atom bombardment mass spectroemtry was evaluated asa means for the quantitative analysis of N-acetylneuraminyl-galactosyl-glucosyl ceramide (NeuAc-GM3) and N-acetylgalactosaminyl-(N-acetylneuraminyl)galactosyl-glucosyl-ceramide (NeuAc-GM3). This study was carried out on a 7070-EQ mass spectrometer (VG Analytical, Manchester, UK) using a home-made continuous-flow fast-atom bombardment probe with a mixture of methanol +water+triethanolamine (70:27:3, v/v/v)as the mobile phase. Utilizing 100 ng of acetyl-lysogalactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl)galactosyl-glucosylceramide (acetyl-lysoGM1) as an internal standard curves for NeuAc-GM3 d18:1-16 0, NeuAc-GM3 d18:1-18:0 and Neuac-GM3 d18:1-18:0 were found to be linear over the range 5-250ng, with associated correlation coefficients of 0.990-0.997. The lower limit of detection was found to be 2.5ng. Satisfactory results could also de obtained when the calibration curves were derived from the deprotonated molecular ions of a mixture of the NeuAc-M2 and NeuAc-GM3 classes. Using this approach, quantitative determination of NeuAc-GM3 d18:1-16:0 from rat adrenal gland was performed sing N-acetylneuraminic acid assay as a test control. We found 278±36 ng of this species in 1 mg of tissue (three replicate experiments). The procedure represents a senstive method for the quantitation of mionosialogangliosides and its capability to give molecular species information.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 793-799 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Characteristics of gas penetration and polymer melt flow in gas-assisted injection molded spiral tubes was investigated by simulations and experiments. Distribution of the skin melt thickness along the gas flow direction was measured, and gas penetration in the primary and secondary stages was identified. An algorithm based on the control-volume/tiniteelement method combined with a particle-tracing scheme using a dual-filling-parameter technique is utilized to predict the advancements of both melt front and gas from during the molding process. The simulated distribution of gas penetration shows reasonably good coincidence with experimental observations. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 724-731 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A methodology is set forth for the numerical solution of the transient freezing problem of a viscous power-law fluid flowing in a cold empty tube with a frozen layer forming on the inside tube surface. The fluid considered is the melt of a semicrystalline polymer with temperature dependent viscosity. The solution domain encompasses both the liquid and solid phases. Coordinate transformations are employed to immobilize and to straighten the moving, curved interface. An implicit finite difference method is employed to solve the governing equations. Numerical results are analyzed by examining the effects of the Peclet number, Nahme number, Stefen number, and the power law index on the profiles of the frozen layer. Variations of the thickness of the frozen layer as a function of time and axial coordinate are also presented.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 20 (1980), S. 40-50 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Diffusivities D ranging over six orders of magnitude with values as low as 2 × 10-13 cm2/s have been obtained by a recently developed permeation apparatus, employing a gas-flow method and a flame ionization detector; Log D for hydrocarbons in bisphenol-A polycarbonate (PC) at 120°C is proportional to the square of the molecular diameter (d2) as given by the Lennard-Jones 6-12 potential. This correlation holds even for the nonspherical n-hexane molecule. The activation energy for diffusion is also linearly related to d2, with values of 9.5 and 23 kcal/mol for methane and neopentane in PC, respectively. Comparison of PC with two similar polymers of higher glass-transition temperatures (Tg) indicates that our diffusion data do not correlate with the Tg of these polymers. The presence of subsidiary transitions, however, appears to enhance segmental mobilities, increasing the rate of diffusion of the hydrocarbons. The thermodynamic solubility of alkanes in glassy PC can be directly related to their boiling points, and in addition, their enthalpy of solution is linearly related to the heat of condensation of these permeants.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 353-370 
    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 experimental study was carried out to investigate the moldability of polymer blends which form two phases in the molten state and the effect of mixing on the morphology and mechanical porperties of molded specimens. Blends of polystyrene with polypropylene and blends of polystyrene with high-density polyethylene were used for this study. A plunger-type injection molding machine (Van Dorn) was employed for molding specimens. To improve the mixing performance of the plunger machine, a Static Mixer (Kenics Corp., Super Nozzle) was installed between the heating cylinder and the sprue. A number of different molding conditions (injection pressure, temperature, injection time, cooling time) were varied, and molded specimens were collected under each molding condition. The specimens were used for studying the degree of dispersion in the blends and for determining the mechanical properties. A differential thermal analysis (DTA) experiment was also carried out to determine the degree of dispersion of the blends in molded specimens. It was found that a linear correlation exists between the blend composition and thermal spectra area of the blends tested.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 2661-2663 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 1706-1714 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Experimental studies of polymer melt flow in the filling and post-filling stages of the injection molding process were performed using the sequential injection of transparent and colored polystyrene resin. Effects of fountain flow in the filling stage, geometrical factors caused by edges and corners, as well as flow through contractions and expansions, were identified. Significant polymer melt flow which increases with increased packing pressure was observed in the post-filling process. The melt flow is more concentrated around the gate area than away from the gate. It was also found that the polymer melt flows across the gap center, resulting in partial annihilation of the weld line. Simulations based on the control-volume/finite-element method employed within each gapwise layer combined with the dual-filling-parameter technique were developed to trace the advancements in melt fronts for both skin and core materials. Numerical simulations show reasonable consistency with experimental results in both skin and core material distribution. If the edge effect is taken into account using a shape factor as a geometrical correction, the simulation accuracy is further improved.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
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