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  • 1985-1989  (2)
  • 82.50  (1)
  • chloride transport  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Laboratory scale-up of two-stage laser chemistry separation of13C from CF2HCl (1985)
    Springer
    Applied physics 36 (1985), S. 63-75 
    Details
    ISSN: 1432-0649
    Keywords: 82.50 ; 33
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The laboratory scale-up of a two-stage laser enrichment process for carbon isotopes, involving infrared multiphoton dissociation of freon-22, is described. Unmodified commercial equipment and materials were used. An initial study of the effect of fluence, laser frequency, freon-22 pressure and pressure of argon, nitrogen and trifluoromethyl chloride was made in short irradiation cells (constant fluence) in order to define optimum process parameters. The process was then scaled to higher throughput in longer cells (1–5 m) in which compensation for beam-energy depletion by absorption was made by reduction in the beam area by focussing. From the scale-up experiments, measurements of yield and enrichment of the tetrafluoroethylene product gave demonstrated production rates. These, coupled with measurements of the absorption, allowed extrapolation to production rates assuming total utilization of the available output energy. Using a 100 W TEA CO2 laser (10 J, 10 Hz) we have demonstrated production rates of 0.20 g h−1 carbon-12 at 99.99% carbon-12, 11 mg h−1 carbon-13 at 72% carbon-13 and 2 kg per annum carbon-13 at 50%. Energy absorption measurements imply a capability to produce 3 kg per annum carbon-13 at over 95% carbon-13 in a two-stage process. The apparatus was used to produce gram quantities of carbon-13 depleted freon-22 (99.99% carbon-12). A comparison of the infrared multiphoton dissociation of this material with that of natural freon-22 (1.11% carbon-13) showed that under the conditions required to give selective dissociation of13CF2HCl that12CF2HCl was excited as a result of a dominantly radiative interaction and that collisional transfer from13CF2HCl molecules played a minor role.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694692
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Activation of Cl−/OH− exchange by parachloromercuribenzoic acid in rabbit renal brush-border membranes (1989)
    Springer
    The journal of membrane biology 112 (1989), S. 59-66 
    Details
    ISSN: 1432-1424
    Keywords: parachloromercuribenzoic acid ; Cl/OH exchange ; sulfhydryl reagents ; chloride transport ; DIDS ; brush-border membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effect of the sulfhydryl reagent parachloromercuribenzoic acid (PCMB) on chloride transport was examined in rabbit renal brush-border membrane vesicles (BBMV). PCMB had no effect on the chloride conductive pathway. In the presence of an inside-alkaline pH gradient and a K+/valinomycin voltage clamp, the addition of PCMB stimulated36Cl uptake and induced a threefold overshoot above the equilibrium value, indicating Cl/OH exchange. The effect of PCMB was reversed by dithiothreitol. Cl/OH exchange was not observed in the absence of PCMB. PCMB-activated Cl/OH exchange persisted even when the membrane potential was made inside-negative relative to the controls, thus, demonstrating that PCMB's effect on36Cl uptake under pH-gradient conditions is not mediated by parallel Cl− and H+ conductive pathways. PCMB-activated Cl/OH exchange was inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) with IC50 values of 290 and 80 μm, respectively. These results demonstrate that modification of sulfhydryl groups by PCMB activates Cl/OH exchange in BBMV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01871164
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    Paper (German National Licenses)
    Fulltext
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