The International Toxicity Equivalency Factor (I-TEF) method of risk assessment for complex mixtures of dioxins and related compounds.

The International Toxicity Equivalency Factor (I-TEF) method of risk assessment is an updated interim procedure for estimating the risks associated with exposures to complex mixtures of chlorinated dibenzo-p-dioxins and dibenzofurans (CDDs and CDFs). The I-TEF approach facilitates risk communication internationally by reducing large volumes of analytical data into a single number-International Toxicity Equivalents (I-TEQ). The I-TEF method has been officially adopted in Canada, the Netherlands, the Nordic countries, the United Kingdom, and the United States. As a result, the I-TEF method represents an improvement in an already useful risk assessment/regulatory tool

Soliton lasers stabilized by coupling to a resonant linear system

Separation into spectral and nonlinear complex-eigenvalue problems is shown to be an effective and flexible approach to soliton laser models. The simplest such model, a complex Ginzburg-Landau model with cubic nonlinearity, has no stable solitonic solutions. We show that coupling it to a resonant linear system is a simple and general route to stabilization, which encompasses several previous instances in both space- and time-domains. Graphical solution in the complex eigenvalue plane provides valuable insight into the similarities and differences of such models, and into the interpretation of related experiments. It can also be used predictively, to guide analysis, numerics and experiment

The enzymatic basis for pesticide bioremediation

Enzymes are central to the biology of many pesticides, influencing their modes of action, environmental fates and mechanisms of target species resistance. Since the introduction of synthetic xenobiotic pesticides, enzymes responsible for pesticide turnover have evolved rapidly, in both the target organisms and incidentally exposed biota. Such enzymes are a source of significant biotechnological potential and form the basis of several bioremediation strategies intended to reduce the environmental impacts of pesticide residues. This review describes examples of enzymes possessing the major activities employed in the bioremediation of pesticide residues, and some of the strategies by which they are employed. In addition, several examples of specific achievements in enzyme engineering are considered, highlighting the growing trend in tailoring enzymatic activity to a specific biotechnologically relevant function