William Stiteler

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The Cadmium Dietary Exposure Model (CDEM) utilizes national survey data on food cadmium concentrations and food consumption patterns to estimate dietary intakes in the U.S. population. The CDEM has been linked to a modification of the cadmium biokinetic model of Kjellström and Nordlberg (KNM) to derive predictions of kidney and urinary cadmium that reflect(More)
Biodegradation half-lives are needed for many applications in chemical screening, but these data are not available for most chemicals. To address this, in phase one of this work we correlated the much more abundant ready and inherent biodegradation test data with measured half-lives for water and soil. In phase two, we explored the utility of the BIOWIN(More)
Two independent training sets were used to develop four mathematical models for predicting aerobic biodegradability from chemical structure. All four of the models are based on multiple regressions against counts of 36 preselected chemical substructures plus molecular weight. Two of the models, based on linear and nonlinear regressions, calculate the(More)
This paper presents a method for identifying and assessing the significance of interaction patterns among various chemicals and chemical classes of importance to regulatory toxicologists. To this end, efforts were made to assemble and evaluate experimental data on toxicologically significant interactions, to use this information to characterize the(More)
The blood clearance and 24-hr organ distribution of five lymphocyte-rich suspensions harvested from different source organs were compared in the Wistar rat, after labeling with [111In]tropolone and intravenous injection. Peripheral blood lymphocytes (chiefly T cells) had the highest levels in the blood and lymph nodes, a relatively higher level in intestine(More)
A file of evaluated biodegradation data was used to develop a model for predicting aerobic biodegradability from chemical structure alone. Chemicals were initially divided into three groups: (i) chemicals that degrade rapidly under most environmental conditions without requiring acclimation; (ii) chemicals that degrade slowly or not at all; and (iii)(More)
A new predictive model for determining quantitative primary biodegradation half-lives of individual petroleum hydrocarbons has been developed. This model uses a fragment-based approach similar to that of several other biodegradation models, such as those within the Biodegradation Probability Program (BIOWIN) estimation program. In the present study, a(More)
Categorical regression is a mathematical tool that can be adapted to estimate potential health risk from chemical exposures. By regressing ordered categories of toxic severity or pathological staging on exposure dose, this method can estimate the likelihood of observing any of the categories of severity at any dose level. Depending on the nature of the(More)
Various indices of spatial patterns based on plot counts are reviewed for theoretical population models appropriate to ecological studies. It is seen that many of the indices proposed in the literature are essentially equivalent to either the index ω= σ2/μ or to the index γ= (σ2-μ)/μ2, thus providing a variety of motiviations and interpretations of these(More)
Recent work indicates that the regression of toxicity data viewed as categories of pathological staging is useful for exploring the likely health risk at doses above a Reference Dose (RfD), which is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely(More)