Improving Cancer Dose–Response Characterization by Using Physiologically Based Pharmacokinetic Modeling: An Analysis of Pooled Data for Acrylonitrile-Induced Brain Tumors to Assess Cancer Potency in the Rat

Historically, U.S. regulators have derived cancer slope factors by using applied dose and tumor response data from a single key bioassay or by averaging the cancer slope factors of several key bioassays. Recent changes in U.S. Environmental Protection Agency (EPA) guidelines for cancer risk assessment have acknowledged the value of better use of mechanistic data and better dose–response characterization. However, agency guidelines may benefit from additional considerations presented in this paper. An exploratory study was conducted by using rat brain tumor data for acrylonitrile (AN) to investigate the use of physiologically based pharmacokinetic (PBPK) modeling along with pooling of dose–response data across routes of exposure as a means for improving carcinogen risk assessment methods. In this study, two contrasting assessments were conducted for AN-induced brain tumors in the rat on the basis of (1) the EPA's approach, the dose–response relationship was characterized by using administered dose/concentration for each of the key studies assessed individually; and (2) an analysis of the pooled data, the dose–response relationship was characterized by using PBPK-derived internal dose measures for a combined database of ten bioassays. The cancer potencies predicted for AN by the contrasting assessments are remarkably different (i.e., risk-specific doses differ by as much as two to four orders of magnitude), with the pooled data assessments yielding lower values. This result suggests that current carcinogen risk assessment practices overestimate AN cancer potency. This methodology should be equally applicable to other data-rich chemicals in identifying (1) a useful dose measure, (2) an appropriate dose–response model, (3) an acceptable point of departure, and (4) an appropriate method of extrapolation from the range of observation to the range of prediction when a chemical's mode of action remains uncertain.     

Collecting text messages from college students: Evaluating a novel methodology

Social interaction, particularly in older adolescents, increasingly involves computer‐mediated communication. Although studies of public computer‐mediated communication are increasingly common, studies of private text messaging remain rare. As approaches for obtaining such data evolve with technological advances, developmental scientists need designs in which to use such approaches that reduce sampling biases in both participants and text messages. In this study (n = 854; 46% male; 22% African American, 60% European American), we examined selection biases in the participant sample (i.e., factors associated with actual participation), procedural biases in the participant sample (i.e., factors related to failed data capture due to technological or procedural issues), and selection biases in the sample of text messages (i.e., based on self‐reported reasons for texting). Findings from our study suggest that studying human interaction directly through analysis of text message data is not only feasible, but also may be successfully undertaken with minimal biases regarding sample selection and text message selection among those who are engaged in research and engaged in text messaging outside of the study context. However, biases may occur depending on the type of platform (iPhone vs. Android) used by participants for texting.     

Choices at various levels of uncertainty: An experimental test of the restated diversification theorem

Our “Restated diversification theorem” (Skogh and Wu, 2005) says that risk-averse agents may pool risks efficiently without assignment of subjective probabilities to outcomes, also at genuine uncertainty. It suffices that the agents presume that they face equal risks. Here, the theorem is tested in an experiment where the probability of loss, and the information about this probability, varies. The result supports our theorem. Moreover, it tentatively supports an evolutionary theory of the insurance industry—starting with mutual pooling at uncertainty, turning into insurance priced ex ante when actuarial information is available.     

Hearing the voices of abused older women

This paper focuses on a qualitative research process that gathered responses from 64 older women aged fifty and older on their experience of violence and abuse. What older women said about abuse in their lives supports the use of a feminist framework as well as the age based analysis of the elder abuse field. Some respondents spoke of abuse from childhood into their later years. Some spoke of partners witnessing or experiencing abuse as children. Some women express concern about possible abuse by their adult children of their own children. Abused older women like younger women need a safe environment, emotional support, advocacy, information, and peer support. While it is important to consider the perspectives and knowledge of service providers when developing policy and practice on abuse of older women, it is critical to ask the women survivors of abuse or neglect what they believe would benefit them, and others in similar situations.     

Learning about radon's risk

This article reports the results of an evaluation of the effectiveness of different types of information materials in communicating the risk from exposure to radon, a naturally occurring indoor air pollutant. The study involved a panel of 2300 homeowners who actually experienced risks from radon, and the information program used to explain these risks. The analysis considered information transfer and performance on specific tasks requiring information on the risk from radon to measure learning. The results suggest a systematic learning process, but indicate that the process can be influenced by how risk information is presented.     

Modeling the Niger Delta Insurgency

Nigeria's oil guarantees its role in the global economy; however, the state's overwhelming weaknesses perpetuate a high level of volatility vis-à-vis the potential for an immediate disruption of the national, regional, and global environment. This study presents a current qualitative analysis of Nigeria to produce a model that characterizes current conditions in the state and the state response to the nefarious acts in the delta region. This model will serve as a baseline for a significant iteration of the model that reflects the delta region counter-insurgency at various levels of strength: a what-if scenario of the region with an increase of state security over southern separatists, insurgents seeking to gain control of the oil assets. The conjectured model serves to inform/educate decision and policy makers in developing proactive, effective strategies to counter existent and potential threats in the Niger Delta.     

Person-oriented research ethics: integrating relational and everyday ethics in research

Research ethics is often understood by researchers primarily through the regulatory framework reflected in the research ethics review process. This regulatory understanding does not encompass the range of ethical considerations in research, notably those associated with the relational and everyday aspects of human subject research. In order to support researchers in their effort to adopt a broader lens, this article presents a “person-oriented research ethics” approach. Five practical guideposts of person-oriented research ethics are identified, as follows: (1) respect for holistic personhood; (2) acknowledgement of lived world; (3) individualization; (4) focus on researcher-participant relationships; and (5) empowerment in decision-making. These guideposts are defined and illustrated with respect to different aspects of the research process (e.g., research design, recruitment, data collection). The person-oriented research ethics approach provides a toolkit to individual researchers, research groups, and research institutions in both biomedical and social science research wishing to expand their commitment to ethics in research.