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  • 1
    Electronic Resource
    Electronic Resource
    The effect of chelation on the selective transport of alkaline-earth metal ions in asymmetric cellulose acetate hyperfiltration membranes (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 1795-1800 
    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 rejection of calcium and/or magnesium ion by asymmetric cellulose acetate hyperfiltration membranes is increased significantly by formation of the corresponding alkaline-earth metal chelate. Typically solute fluxes are reduced by a factor of 5 consequent to chelation with ethylenediaminetetraacetic acid (EDTA) at pH 6.0. Selective chelation and, in turn, selective transport of magnesium is observed when equimolar solute mixtures corresponding to 1:1:1 magnesium:calcium:EDTA are hyperfiltered. Under these conditions, calcium successfully competes for the stoichiometrically limiting EDTA, and the rejection of magnesium is lower than the rejection observed for the hyperfiltration of the MgEDTA2- complex in the absence of competitive calcium. Alternatively, the rejection of the CaEDTA2- complex is increased under these identical conditions, presumably as a consequence of specific interactions between the available free magnesium and the cellulose acetate membrane. The effects reported here all seem to be related to reductions in solute diffusivity associated with the increased size of the alkaline-earth metal ion complex.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210707
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  • 2
    Electronic Resource
    Electronic Resource
    Profiles of volatile metabolites in biological fluids using capillary columns (1979)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 2 (1979), S. 423-428 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, nickel ; „Transevaporator“ into packed pre-column as sampling technique prior capillary described ; Application to volatile metabolite body fluid analysis for early detection of disease ; Serum and human breast milk as examples ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nickel capillary columns coated with moderately polarstationary phases such as Witconol can be used for the separation of the organic volatile fraction from biological fluids. A “transevaporator” sampling technique for the collection of the organic volatiles on glass beads from as little as 5 to 500 μl of biological fluids (e.g. urine, serum, amniotic fluid, breast milk, saliva, etc.) is described. The organic volatiles are thermally desorbed from the glass beads into a short precolumn cooled in liquid nitrogen, which overcomes the problems associated with sample introduction onto narrow-bore capillary columns. The application of the full analytical technique to problems associated with the early detection of disease is illustrated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240020710
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  • 3
    Electronic Resource
    Electronic Resource
    On-line optimizing control of a nonadiabatic fixed bed reactor (1985)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 31 (1985), S. 667-675 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A scheme of on-line optimizing control is presented for a nonadiabatic fixed bed reactor which experiences a highly exothermic reaction. The control scheme has been devised to perform adaptive control of bed temperature and on-line steady state optimization simultaneously.Experiments were conducted with a pilot scale fixed bed reactor where partial oxidation of n-butane to maleic anhydride occurs. The reactor system was interfaced with a microcomputer for real-time control and optimization. With an objective function consisting of a net profit by producing maleic anhydride plus a penalty term on high bed temperature, it was clearly shown that the reaction conditions were driven to the expected optimum region.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690310417
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of chelation on the selective transport of alkaline earth metal ions in asymmetric cellulose acetate hyperfiltration membranes. II (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 1093-1104 
    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 effects of chelation on the transport of calcium and magnesium, both separately and in a variety of admixtures, in a controlled series of asymmetric cellulose acetate membranes were characterized. Ethylenediaminetetraacetic acid (EDTA) and ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA) were used as chelating agents for the alkaline earth metal ions. Asymmetric cellulose acetate membranes annealed at 70°, 75°, and 85°C were studied. Chelation of each of these alkaline earth metals ions in aqueous solutions at pH 6, by either EDTA or EGTA, significantly increased the overall hyperfiltration rejections of these metals by all the membranes studied. The increase in rejection varied montonically with the fraction of metal ion complexed. The higher rejection of metal chelates, compared to the rejection of unbound metal ions, was considered to be the result of the significantly larger size of the chelated species. Calculations suggested that selective (or competitive) chelation took place at pH 6 in a mixture of calcium and magnesium ions in the presence of a stoichiometrically limiting amount of chelating agent. Calcium successfully competed for most of the available chelating agent in equimolar aqueous solutions of chelating agent, calcium, and magnesium. The calcium rejection was explained primarily in terms of the effects of chelation per se on the effective size of the formed complex even in feeds comprised of these ternary solute mixtures. The complexation reaction between magnesium and EGTA is, however, so unfavorable at pH 6 that the Mg2+ ion remains uncomplexed even in the presence of an equivalent amount of EGTA. The observed increased rejection of magnesium ions, therefore, in ternary systems was explained by electroneutrality criteria and by solute-membrane interactions involving the various calcium species and the membranes.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220418
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  • 5
    Electronic Resource
    Electronic Resource
    Interactions of dimethyl sulfoxide and granulocyte-macrophage colony-stimulating factors on the growth and maturation of HL-60 cells (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 132 (1987), S. 246-254 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have studied the interactions of dimethyl sulfoxide (DMSO), Giant Cell Tumor (GCT) cell-conditioned medium (GCT CM), and highly purified granulocyte-macrophage colony-stimulating factors (GM-CSF) on the growth and maturation of a highly passaged population of HL-60 cells. DMSO produced dose-dependent inhibition of HL-60 growth in liquid and semisolid media. Growth was partially to completely restored by the addition of GCT CM to cultures. Experiments in which cell volume, cell cycle kinetics, tritiated thymidine (3HTdr) incorporation, cell number, and nitroblue tetrazolium (NBT) reduction were compared during culture indicated that DMSO inhibited the spontaneous increase in cell volume and flow of cells through the cell cycle which occurred in the first day of culture, the increase in 3HTdr incorporation which was detectable by day 2; and the increment in cell counts which occurred by day 3. These effects were opposed by GCT CM. In contrast, the DMSO-induced increase in NBT reduction which occurred by day 6 was not influenced by GCT CM. The major principle opposing DMSO was GM-CSF, since (1) highly purified GM-CSF from GCT cells and recombinant GM-CSF from COS cells transfected with the Mo cell GM-CSF gene overcame greater than 50% of DMSO inhibition; and (2) conditioned media from cells not producing CSF, G-CSF from GCT cells, and recombinant G-CSF from Escherichia coli transfected with the G-CSF gene from 5,637 cells were inactive. DMSO had little or no effect on the elaboration of autostimulatory activity by HL-60 cells. DMSO is a useful agent for inhibiting the spontaneous growth of HL-60 cells and restoring their dependence on GM-CSF, a property which may be mediated through the effects of DMSO on cell cycle kinetics and/or maturation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041320208
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