Visualizing the NIOSH Pocket Guide: Open-source web application for accessing and exploring the NIOSH Pocket Guide to Chemical Hazards.

The NIOSH Pocket Guide to Chemical Hazards is a trusted resource that displays key information for a collection of chemicals commonly encountered in the workplace. Entries contain chemical structures-occupational exposure limit information ranging from limits based on full-shift time-weighted averages to acute limits such as short-term exposure limits and immediately dangerous to life or health values, as well as a variety of other data such as chemical-physical properties and symptoms of exposure. The NIOSH Pocket Guide (NPG) is available as a printed, hardcopy book, a PDF version, an electronic database, and a downloadable application for mobile phones.

Impact of Organism Allocations on Potency Estimates from Ceriodaphnia dubia Reproduction Tests.

In aquatic toxicology experiments, organisms are randomly assigned to an exposure group that receives a particular concentration level of a toxicant (including a control group with no exposure), and their survival, growth, or reproduction outcomes are recorded. Standard experiments use equal numbers of organisms in each exposure group. In the present study, we explored the potential benefits of modifying the current design of aquatic toxicology experiments when it is of interest to estimate the concentration associated with a specific level of decrease from control reproduction responses.

ToxicR: A computational platform in R for computational toxicology and dose-response analyses.

The need to analyze the complex relationships observed in high-throughput toxicogenomic and other omic platforms has resulted in an explosion of methodological advances in computational toxicology. However, advancements in the literature often outpace the development of software researchers can implement in their pipelines, and existing software is frequently based on pre-specified workflows built from well-vetted assumptions that may not be optimal for novel research questions. Accordingly, there is a need for a stable platform and open-source codebase attached to a programming language that allows users to program new algorithms.

Identifying sensitive windows of airborne lead exposure associated with behavioral outcomes at age 12.

Unlabelled: Despite the precipitous decline of airborne lead concentrations following the removal of lead in gasoline, lead is still detectable in ambient air in most urban areas. Few studies, however, have examined the health effects of contemporary airborne lead concentrations in children.

Methods: We estimated monthly air lead exposure among 263 children (Cincinnati Childhood Allergy and Air Pollution Study; Cincinnati, OH; 2001-2005) using temporally scaled predictions from a validated land use model and assessed neurobehavioral outcomes at age 12 years using the parent-completed Behavioral Assessment System for Children, 2nd edition.

On the impact of sample size on median lethal concentration estimation in acute fish toxicity testing: Is n = 7/group enough?

The fish acute toxicity test method is foundational to aquatic toxicity testing strategies, yet the literature lacks a concise sample size assessment. Although various sources address sample size, historical precedent seems to play a larger role than objective measures. We present a novel and comprehensive quantification of the effect of sample size on estimation of the median lethal concentration (LC50), covering a wide range of scenarios.

Bayesian Quantile Impairment Threshold Benchmark Dose Estimation for Continuous Endpoints.

Quantitative risk assessment often begins with an estimate of the exposure or dose associated with a particular risk level from which exposure levels posing low risk to populations can be extrapolated. For continuous exposures, this value, the benchmark dose, is often defined by a specified increase (or decrease) from the median or mean response at no exposure. This method of calculating the benchmark dose does not take into account the response distribution and, consequently, cannot be interpreted based upon probability statements of the target population.

Selecting the best design for nonstandard toxicology experiments.

Although many experiments in environmental toxicology use standard statistical experimental designs, there are situations that arise where no such standard design is natural or applicable because of logistical constraints. For example, the layout of a laboratory may suggest that each shelf serve as a block, with the number of experimental units per shelf either greater than or less than the number of treatments in a way that precludes the use of a typical block design. In such cases, an effective and powerful alternative is to employ optimal experimental design principles, a strategy that produces designs with precise statistical estimates.

An empirical comparison of low-dose extrapolation from points of departure (PoD) compared to extrapolations based upon methods that account for model uncertainty.

Experiments with relatively high doses are often used to predict risks at appreciably lower doses. A point of departure (PoD) can be calculated as the dose associated with a specified moderate response level that is often in the range of experimental doses considered. A linear extrapolation to lower doses often follows.

Impact of exchanges and client-therapist alliance in online-text psychotherapy.

The impact of exchanges and client-therapist alliance of online therapy text exchanges were compared to previously published results in face-to-face therapy, and the moderating effects of four participant factors found significant in previously published face-to-face studies were investigated using statistical mixed-effect modeling analytic techniques. Therapists (N=30) and clients (N=30) engaged in online therapy were recruited from private practitioner sites, e-clinics, online counseling centers, and mental-health-related discussion boards. In a naturalistic design, they each visited an online site weekly and completed the standard impact and alliance questionnaires for at least 6 weeks.

Worker injuries and safety equipment in Ohio nursing homes.

A survey of Ohio nursing homes was conducted in 2007 to examine whether injury rates were related to facility characteristics and availability of safety equipment. The median rate of injury in the 898 facilities was 5.7 injuries per 100 workers per year.

Bayesian approach to potency estimation for aquatic toxicology experiments when a toxicant affects both fecundity and survival.

Chemicals in aquatic systems may impact a variety of endpoints including mortality, growth, or reproduction. Clearly, growth or reproduction will only be observed in organisms that survive. Because it is common to observe mortality in studies focusing on the reproduction of organisms, especially in higher concentration conditions, the resulting observed numbers of young become a mixture of zeroes and positive counts.

Risk factors of falls in community-dwelling older adults: logistic regression tree analysis.

Purpose Of The Study: A novel logistic regression tree-based method was applied to identify fall risk factors and possible interaction effects of those risk factors.

Design And Methods: A nationally representative sample of American older adults aged 65 years and older (N = 9,592) in the Health and Retirement Study 2004 and 2006 modules was used. Logistic Tree with Unbiased Selection, a computer algorithm for tree-based modeling, recursively split the entire group in the data set into mutually exclusive subgroups and fit a logistic regression model in each subgroup to generate an easily interpreted tree diagram.

Bayesian approach to estimating reproductive inhibition potency in aquatic toxicity testing.

Effectively and accurately assessing the toxicity of chemicals and their impact on the environment continues to be an important concern in ecotoxicology. Single experiments conducted by a particular laboratory commonly serve as the basis of toxicity risk assessment. These laboratories often have a long history of conducting experiments using particular protocols.

Monotonic Bayesian semiparametric benchmark dose analysis.

Quantitative risk assessment proceeds by first estimating a dose-response model and then inverting this model to estimate the dose that corresponds to some prespecified level of response. The parametric form of the dose-response model often plays a large role in determining this dose. Consequently, the choice of the proper model is a major source of uncertainty when estimating such endpoints.

Baseline characteristics and statistical implications for the OECD 210 fish early-life stage chronic toxicity test.

The fish toxicity assay most commonly used to establish chronic effects is the Organisation for Economic Co-operation and Development (OECD) 210, fish early-life stage test. However, the authors are not aware of any systematic analysis of the experimental design or statistical characteristics of the test since the test guideline was adopted nearly 20 years ago. Here, the authors report the results of an analysis of data compiled from OECD 210 tests conducted by industry labs.

Fall risk factors in community-dwelling elderly who receive Medicaid-supported home- and community-based care services.

Objective: This study identifies fall risk factors in an understudied population of older people who receive community-based care services.

Method: Data were collected from enrollees of Ohio's Medicaid home- and community-based waiver program (preadmission screening system providing options and resources today [PASSPORT]). A total of 23,182 participants receiving PASSPORT services in 2005/2006 was classified as fallers and nonfallers, and a variety of risk factors for falling was analyzed using logistic regressions.

Comparing weighted and unweighted analyses applied to data with a mix of pooled and individual observations.

Smaller organisms may have too little tissue to allow assaying as individuals. To get a sufficient sample for assaying, a collection of smaller individual organisms is pooled together to produce a simple observation for modeling and analysis. When a dataset contains a mix of pooled and individual organisms, the variances of the observations are not equal.

Comparing methods for analyzing overdispersed count data in aquatic toxicology.

Endpoints in aquatic toxicity tests can be measured using a variety of measurement scales including dichotomous (survival), continuous (growth) and count (number of young). A distribution is assumed for an endpoint and analyses proceed accordingly. In certain situations, the assumed distribution may be incorrect and this may lead to incorrect statistical inference.

Combining information.

The combination of information from diverse sources is a common task encountered in computational statistics. A popular label for analyses involving the combination of results from independent studies is meta-analysis. The goal of the methodology is to bring together results of different studies, re-analyze the disparate results within the context of their common endpoints, synthesize where possible into a single summary endpoint, increase the sensitivity of the analysis to detect the presence of adverse effects, and provide a quantitative analysis of the phenomenon of interest based on the combined data.

Impact of publicly sponsored interventions on musculoskeletal injury claims in nursing homes.

Background: The rate of lost-time sprains and strains in private nursing homes is over three times the national average, and for back injuries, almost four times the national average. The Ohio Bureau of Workers' Compensation (BWC) has sponsored interventions that were preferentially promoted to nursing homes in 2000-2001, including training, consultation, and grants up to $40,000 for equipment purchases.

Methods: This study evaluated the impact of BWC interventions on back injury claim rates using BWC data on claims, interventions, and employer payroll for all Ohio nursing homes during 1995-2004 using Poisson regression.

Political economy of US states and rates of fatal occupational injury.

Objectives: We investigated the extent to which the political economy of US states, including the relative power of organized labor, predicts rates of fatal occupational injury.

Methods: We described states' political economies with 6 contextual variables measuring social and political conditions: "right-to-work" laws, union membership density, labor grievance rates, state government debt, unemployment rates, and social wage payments. We obtained data on fatal occupational injuries from the National Traumatic Occupational Fatality surveillance system and population data from the US national census.

Model-averaged benchmark concentration estimates for continuous response data arising from epidemiological studies.

Worker populations often provide data on adverse responses associated with exposure to potential hazards. The relationship between hazard exposure levels and adverse response can be modeled and then inverted to estimate the exposure associated with some specified response level. One concern is that this endpoint may be sensitive to the concentration metric and other variables included in the model.

Comparing methods for analyzing overdispersed binary data in aquatic toxicology.

Historically, death is the most commonly studied effect in aquatic toxicity tests. These tests typically employ a gradient of concentrations and exposure with more than one organism in a series of replicate chambers in each concentration. Whereas a binomial distribution commonly is employed for such effects, variability may exceed that predicted by binomial probability models.

Benchmark dose estimation incorporating multiple data sources.

With the increased availability of toxicological hazard information arising from multiple experimental sources, risk assessors are often confronted with the challenge of synthesizing all available scientific information into an analysis. This analysis is further complicated because significant between-source heterogeneity/lab-to-lab variability is often evident. We estimate benchmark doses using hierarchical models to account for the observed heterogeneity.

A review and characterization of the MDS process in nursing homes.

The Minimum Data Set (MDS) is a tool used by nursing homes for resident assessment and care planning, indicating facility quality and the extent of residents' care needs. The process by which the MDS is completed by facilities has not been empirically studied. Understanding common strategies and practices for completing the MDS helps further comprehend the validity of the MDS and its relevance for focusing on residents and implementing clinical nursing interventions.