background: the pollution of the aquatic environment with heavy metals has become a worldwide problem during recent years, due to their potential toxic effects and ability to bio-accumulate in aquatic ecosystems. heavy metals are sensitive indicators for monitoring changes in the aquatic environment. methods: in this study, total concentrations of cr, pb, cu, zn, and fe were measured in water a...

The malarial parasite, Plasmodium falciparum, is an intracellular pathogen and partially dependent on nutrient uptake for survival. In this issue of Chemistry & Biology, Marvin et al. demonstrate that zinc is essential for parasite growth and that the parasite maintains substantial labile cytosolic and mitochondrial zinc pools.

when organic material is decomposed under oxygen-limiting conditions (Nedwell, 1982). (The term sulphide is intended to include undissociated H2S, the bisulphide anion HS− and the sulphide anion S2−.) In marine sediments, sulphide production is enhanced by bacterial sulphate reduction (Jorgensen and Fenchel, 1974; Nedwell, 1982). Species inhabiting intertidal flats or salt marshes are, therefor...

The gene myogenin encodes a helix-loop-helix protein whose function is critical to the integrity of the mammalian myogenic cascade. In vitro, the expression of this gene immediately precedes terminal differentiation, as measured by the synthesis of those proteins that make up the contractile apparatus. However, during mammalian development, expression of myogenin and the appearance of sarcomere...

It appears as if the failure of one organ system precipitates the subsequent failure of other organ systems. The aim of the present analysis is to model such system behavior and understand why medical complications accumulate in individual patients. The human body is first modeled as being comprised of multiple subsystems, with the health of each subsystem dependent on input regarding its own h...

Repeat-Accumulate (RA) codes, consisting of a simple binary repetition followed by a permutation and an accumulator, are converting into quasi-cyclic codes with multiple cross-linked cycles. The algebraic heuristics are used to design codes with an explicit algebraic permutation yielding desirable graph properties. Recursive graph constructions techniques are given for the construction of very ...