AIMS To establish and analyse reference data for the mercury burden of patients with and without amalgam fillings. METHODS Atomic absorption spectroscopy was used to quantify Hg concentrations in the scalp hair and urine (before and after application of dimercaptopropane sulphonate), and Hg release from dental amalgams (using a newly developed, amalgam specific chew test), in 2223 subjects. ...

Bacterial chemoreceptors form ternary signaling complexes with the histidine kinase CheA through the coupling protein CheW. Receptor complexes in turn cluster into cellular arrays that produce highly sensitive responses to chemical stimuli. In Escherichia coli, receptors of different types form mixed trimer-of-dimers signaling teams through the tips of their highly conserved cytoplasmic domains...

The combinatorial complexity of the Voronoi diagram of n lines in three dimensions under a convex distance function induced by a polytope with a constant number of edges is shown to be O n n log n where is a slowly growing inverse of the Ackermann function There are arrangements of n lines where this complexity can be as large as n n Work by Paul Chew and Klara Kedem has been supported by AFOSR...

Chemoreceptors such as Tsr, the serine receptor, function in trimer-of-dimer associations to mediate chemotactic behavior in Escherichia coli. The two subunits of each receptor homodimer occupy different positions in the trimer, one at its central axis and the other at the trimer periphery. Residue N381 of Tsr contributes to trimer stability through interactions with its counterparts in a centr...

Bacteria are able to sense chemical gradients over a wide range of concentrations. However, calculations based on the known number of receptors do not predict such a range unless receptors interact with one another in a cooperative manner. A number of recent experiments support the notion that this remarkable sensitivity in chemotaxis is mediated by localized interactions or crosstalk between n...

The team signaling model for bacterial chemoreceptors proposes that receptor dimers of different detection specificities form mixed trimers of dimers. These receptor "squads" then recruit the cytoplasmic signaling proteins CheA and CheW to form ternary signaling teams, which typically cluster at the poles of the cell. We devised cysteine-directed in vivo crosslinking approaches to ask whether m...

The behavior of individually kept PIC Camboroughsows was compared when they were housed in three systems: pasture, soil or gestation crates. All sows were fed 2.0 kg of fortified, sorghum-soybean diet each day. Crated sows were divided into two groups: those fed meal and those fed pellets. As is common among sows on pasture and soil, outdoor sows were fed pellets. Eight sows per treatment were ...

the elementary reaction of kaon exclusive electroproduction on protons has been studied ina broad kinematical range. data for the calculation of the form factor of the kaon have been taken atdifferent values of the invariant center of mass energy w in the range w=1.8, 1.85, 1.98, 2.08 (gev), forone value of the transferred 4-momentum q2=2.35 (gev/c)2. in this analysis, we calculated σl and σt b...