Screening analysis of volatile organic contaminants in commercial inorganic coagulants used for drinking water treatment.

A method for quality screening is suggested to detect volatile impurities in inorganic coagulants that are used for drinking water treatment. Static headspace gas chromatography with mass spectrometry detection (HS-GCMS) is sensitive and selective to detect volatiles in low concentrations. This study has discovered that volatile organic impurities are detectable in ferric and aluminium-based coagulants which are used for drinking water treatment. For ferric chloride, 2-propanol was detected at a level of 17-24 microg ml(-1), acetone at 0.7-1.7 microg ml(-1), 1,1,1-trichloroacetone at 0.02-0.04 microg ml(-1), trichloromethane at 0.01-0.02 microg ml(-1) and toluene at 0.01-0.12 microg ml(-1). For ferric chloride sulfate, acetone was detected at a level of 0.12 microg ml(-1), 1,1,1-trichloroacetone at 0.06-0.08 microg ml(-1), trichloromethane at 0.13-0.23 microg ml(-1), bromodichloromethane at 0.04-0.06 microg ml(-1) and dibromochloromethane at 0.04-0.05 microg ml(-1). For aluminium hydroxide chloride, only trichloromethane was detectable, but below the method detection limits (MDL). Although the concentrations of these impurities in commercial coagulants are low, this observation is important and should have impact on water industries for them to pay attention to the chemicals they are using for drinking water production.

Motion-dependent levels of order in a relativistic universe.

Consider a generally closed system of continuous three-space coordinates x with a differentiable amplitude function ψ(x). What is its level of order R? Define R by the property that it decreases (or stays constant) after the system is coarse grained. Then R turns out to obey R=8(-1)L(2)I,where quantity I=4∫dx[nabla]ψ(*)·[nabla]ψ is the classical Fisher information in the system and L is the longest chord that can connect two points on the system surface. In general, order R is (i) unitless, and (ii) invariant to uniform stretch or compression of the system. On this basis, the order R in the Universe was previously found to be invariant in time despite its Hubble expansion, and with value R=26.0×10(60) for flat space. By comparison, here we model the Universe as a string-based "holostar," with amplitude function ψ(x)[proportionality]1/r over radial interval r=(r(0),r(H)). Here r(0) is of order the Planck length and r(H) is the radial extension of the holostar, estimated as the known value of the Hubble radius. Curvature of space and relative motion of the observer must now be taken into account. It results that a stationary observer observes a level of order R=(8/9)(r(H)/r(0))(3/2)=0.42×10(90); while for a free-falling observer R=2(-1)(r(H)/r(0))(2)=0.85×10(120). Both order values greatly exceed the above flat-space value. Interestingly, they are purely geometric measures, depending solely upon ratio r(H)/r(0). Remarkably, the free-fall value ~10(120) of R approximates the negentropy of a universe modeled as discrete. This might mean that the Universe contains about equal amounts of continuous and discrete structure.

Effects of dexamethasone on antral mucosal protein and gastric development in postnatal rats.

BACKGROUND: The rat stomach undergoes major developmental changes postnatally. An antral mucosal protein (AMP-18) with in vitro mitogenic activity has recently been found in the mammalian stomach. METHODS: To evaluate the role of AMP-18 in gastric development in postnatal rats, the AMP-18 content of glandular stomach extracts from postnatal rats at different ages were measured by Western blots using anti-AMP-18 specific serum. Dexamethasone administration was used to evaluate the corticosteroid regulation of AMP-18 expression. RESULTS: AMP-18 was detected only in glandular stomach homogenate and gastric mucus. AMP-18 and pepsin levels were high at birth. Both decreased postnatally to low levels at 7 days of age, then increased at 10-15 days of age and reached peak levels around weaning (18-21 days of age). The glandular stomach showed stepwise growth relative to body weight, with a significant increase at 18-20 days of age. The forestomach showed a decrease in growth relative to body weight during the same period. Dexamethasone given to pups before 7 days of age induced the accumulation of AMP-18 and pepsin. Induction of AMP-18 by dexamethasone was evident by 7 hours with a delayed increase in glandular stomach mass 30 hours after dexamethasone injection. Induction of AMP-18 by dexamethasone was attenuated by RU-486 but not by spironolactone. CONCLUSION: Increases in AMP-18, pepsin and glandular stomach mass during normal postnatal development suggest that AMP-18 might be involved in gastric maturation, at least in the glandular portion. Dexamethasone induction of pepsin and AMP-18 and the subsequent increase in glandular stomach mass also suggest a possible role for AMP-18 in glandular stomach maturation. Dexamethasone apparently acts through the type II corticosteroid receptor to induce AMP-18.