Marshes

Marsh s test for arsenic The arsenic-containing specimen is converted to volatile AsHs which is decomposed to a brown stain on heating. Estimation is by comparison of stains. Sb reacts similarly but the Sb stain is not soluble in NaOCl. 

Marsh R E and Hughes R J 1989 Quadrupole Storage Mass Spectrometry (New York Wiley-Intersolenoe)... 

Head A J and Sabbah R 1987 Enthalpy Recommended Reference Materials for the Realization of Physicochemical Properties ed K N Marsh (Oxford Blackwell)... 

Marsh K N and O Hare PAG (eds) 1994 Solution Calorimetry, Experimental Thermodynamics vol IV (Oxford Blackwell)... 

Arsenic present only in traces (in any form) can be detected by reducing it to arsine and then applying tests for the latter. In Marsh s test, dilute sulphuric acid is added dropwise through a thistle funnel to some arsenic-free zinc in a flask hydrogen is evolved and led out of the flask by a horizontal delivery tube. The arsenic-containing compound is then added to the zinc-acid solution, and the delivery tube heated in the middle. If arsenic is present, it is reduced to arsine by the zinc-acid reaction, for example ... 

As can be expected, antimony compounds resemble those of arsenic. In the Marsh test, antimony compounds again give a black deposit which, unlike that formed by arsenic compounds, is insoluble in sodium chloratefi) solution. 

Although extraction of lipids from membranes can be induced in atomic force apparatus (Leckband et al., 1994) and biomembrane force probe (Evans et al., 1991) experiments, spontaneous dissociation of a lipid from a membrane occurs very rarely because it involves an energy barrier of about 20 kcal/mol (Cevc and Marsh, 1987). However, lipids are known to be extracted from membranes by various enzymes. One such enzyme is phospholipase A2 (PLA2), which complexes with membrane surfaces, destabilizes a phospholipid, extracts it from the membrane, and catalyzes the hydrolysis reaction of the srir2-acyl chain of the lipid, producing lysophospholipids and fatty acids (Slotboom et al., 1982 Dennis, 1983 Jain et al., 1995). SMD simulations were employed to investigate the extraction of a lipid molecule from a DLPE monolayer by human synovial PLA2 (see Eig. 6b), and to compare this process to the extraction of a lipid from a lipid monolayer into the aqueous phase (Stepaniants et al., 1997). 

Brent et al., 1989] Brent, G. A., Dunn, M. K., Harney, J. W., Gulick, T., and Larsen, P. R. Thyroid hormone aporeceptor represses Ta inducible promoters and blocks activity of the retinoic acid receptor. New Biol. 1 (1989) 329-336 [Cevc and Marsh, 1987] Cevc, G., and Marsh, D. Phospholipid Bilayers Physical Principles and Models. John Wiley Sons, New York, 1987. 

Virtually anywhere water contacts organic matter in the absence of air is a suitable place for methanoarchaea to thrive—at the bottom of ponds bogs and rice fields for example Marsh gas (swamp gas) IS mostly methane Methanoarchaea live inside termites and grass eating animals One source quotes 20 L/day as the methane output of a large cow... 

Fig. 4.20 DR plots for carbon dioxide adsorbed at 293 K on Linde molecular sieves. O, powder SA , powder 4A. (Reduced from the original diagram of Lamond and Marsh. )...

A major difficulty in testing the validity of predictions from the DR equation is that independent estimates of the relevant parameters—the total micropore volume and the pore size distribution—are so often lacking. However, Marsh and Rand compared the extrapolated value for from DR plots of CO2 on a series of activated carbons, with the micropore volume estimated by the pre-adsorption of nonane. They found that except in one case, the value from the DR plot was below, often much below, the nonane figure (Table 4.9). 

Fig. 4.22 Apparent specific surface A(app) of carbons obtained from the decomposition of polymers, plotted against the carbonization temperature, (a) Polyfurfuryl carbons (b) dibenzanthrone carbons (c) polyvinylchloride carbons. O, A(app) estimated from CO2 isotherm at 195 K (a fCOj) = 17-0 A ) A. /f(app) estimated from N2 isotherm at 77 K = 16-2 A ). (Courtesy Marsh and Wynne Jones.)...

H. Marsh and B. Rand, in Third Conference on Industrial Carbon and Graphite (Soc. Chem. Ind.), p. 93, Academic Press, London and New York (1970). 

Marsh and Pond S ediments. Herbicides and pesticides are detectable ia marsh and pond sediments, but intrinsic biodegradation is usually found to be occurting. Littie work has yet been presented where the biodegradation of these compounds has been successfully stimulated by a bioremediation approach. 

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