We model the plumes raised by impacting fragments of comet Shoemaker-Levy 9 to calculate synthetic plume views, atmospheric infall fluxes, and debris patterns. Our plume is a swarm of ballistic particles with one of several mass-velocity distributions (MVD). The swarm is ejected instantaneously and uniformly into a cone from its apex. Upon falling to the ejection altitude, particles slide with ...

Selenocysteine (Sec) residues occur in thiol oxidoreductase families, and functionally characterized selenoenzymes typically have a single Sec residue used directly for redox catalysis. However, how new Sec residues evolve and whether non-catalytic Sec residues exist in proteins is not known. Here, we computationally identified several genes with multiple Sec insertion sequence (SECIS) elements...

Coronary circulation time was measured in 17 dogs using a micro G-M counter attached to the tip of catheter and a radioactivity recording circuit with minimal time delay. P32-orthophosphate sodium solution was injected instantaneously into the left ventricle and its arrival into the right side of the heart was monitored in situ with the G-M counter. A biphasic curve was recorded in the right ve...

We report the development of a new class of readily prepared chiral 4-(pyrrolidino)-pyridine catalysts capable of exploiting both van der Waals (pi) and H-bonding interactions, thus allowing remote chiral information to stereochemically control the kinetic resolution of sec-alcohols.

An experimental database is compiled in order to fingerprint the scales formed over the hot surfaces of heat exchangers, in cooling water systems or other systems with similar chemistry. To collect these data, a dynamic simulating pilot plant was designed with considerable application flexibility among which simultaneous flow of water with different velocity and heat fluxes to three simulat...