Membranes Pyridine data

We begin by comparing fluxes of the permeant molecule pyridine in untreated and thiol-treated nanotubule membranes. An untreated membrane that contained tubules with diameters of approximately 2.6 nm showed a pyridine flux of 1.8 X 10 mol cm hr. After chemisorption of the R = -C2H4-OH thiol the flux increased to 4.2 X 10 mol cm hr. In contrast, after chemisorption of the R = -C16H33 thiol, the pyridine flux dropped to 2.7 X 10 mol cm hr. These data clearly show that thiol chemisorption has a dramatic effect on permeant flux in these nanotubule membranes. 

Au nanotubule membranes with the following approximate nanotubule diameters were used to obtain the majority of the data reported here i.d. = 28 1, 7.0 0.1, 1.9 0.1, and 1.5 0.2 nm. Figure 19 shows permeation data for transport of pyridine through these various membranes. Data for membranes derivatized with both the R = -C2H4-OH (upper solid curve) and the R = -C16H33 (lower dashed curve) thiols are shown. The corresponding flux data are shown in Table 3. As would be expected [114], the flux of pyridine decreases with decreasing tubule diameter for both the... 

The hydrogenosomal membrane displays selective permeability, thereby presenting an effective barrier to pyridine nucleotides and coenzyme A (Cerkasovov et al. 1978 Lindmark and Muller 1973 Muller 1973 Steinbiichel and Muller 1986). Transport of metabolic substrates and products across the hydrogenosomal membrane remains to be studied, but isolated T. foetus hydrogenosomes were shown to readily accumulate both radiolabeled pyruvate and malate (our unpublished data). 

NIOSH REL (Chromium(VI)) TWA 0.025 mg(Cr(VI))/mh CL 0.05/15M SAFETY PROFILE Confirmed human carcinogen. Poison by subcutaneous route. Mutation data reported. A powerful oxidizer. A powerful irritant of skin, eyes, and mucous membranes. Can cause a dermatitis, bronchoasthma, chrome holes, damage to the eyes. Dangerously reactive. Incompatible with acetic acid, acetic anhydride, tetrahydronaphthalene, acetone, alcohols, alkali metals, ammonia, arsenic, bromine penta fluoride, butyric acid, n,n-dimethylformamide, hydrogen sulfide, peroxyformic acid, phosphorus, potassium hexacyanoferrate, pyridine, selenium. 

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