ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

As the first article of a two‐part series, the purpose of this paper is to examine the functional factors that contribute to automobile accident occurrence and to model the causation structure in the form of a fault‐tree. The fault‐tree model provides an intuitive framework for qualitatively decomposing possible pathways to accident occurrence. Fault‐tree analysis also provides a statistical representation of how interacting driver, vehicle, and environmental factors contribute to the likelihood of automobile accident occurrence. The application of this model facilitates pinpointing those factors that most contribute to accident causation and subsequently enables the identification and comparison of potential crash avoidance techn

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00323.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A method to determine how much reduction in public exposure to power frequency magnetic fields can be obtained for different levels of investment is presented. Which if any “effects function” best describes the relationship between field exposure and biological effect is uncertain at this time. Also, in a particular context such as construction of new transmission lines there are a variety of different technologies which might be used to reduce exposure. We describe and demonstrate a method by which exposure reduction supply curves (i.e., the cost of purchasing different amounts of exposure reduction given various mitigation options) can be estimated parametrically for different exposure conditions and effects functions, and we display illustrative resu

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00324.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Several major epidemiological studies have reported significant mortality rates (SMRs) for both rare cancers (soft tissue sarcoma, non‐Hodgkin's, lymphoma, liver) and the more common cancers (lung, colon, etc), all allegedly caused by TCDD. In this paper, we use the potency of TCDD in animals to establish a plausible worst case cancer risk and ask whether its likely that TCDD is responsible for the epidemiological findings assuming the animal carcinogenic potency is applicable to the conditions of human exposure. Two new features of the technique are the use of measured TCDD blood levels in both animals and humans for dose scale‐up and the calculation of an integrated life‐time exposure for the exposed workers using measured blood levels. On the basis of the stated assumptions it appears unlikely that any of the major epidemiological studies, with the possible exception of the NIOSH study(1)have adequate power to detect the common cancers potentially caused by

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A physiologically‐based pharmacokinetic (PBPK) model for a mixture of toluene (TOL) and xylene (XYL), developed and validated in the rat, was used to predict the uptake and disposition kinetics of TOL/XYL mixture in humans. This was accomplished by substituting the rat physiological parameters and the blood:air partition coefficient with those of humans, scaling the maximal velocity for hepatic metabolism on the basis of body weight0.75, and keeping all other model parameters species‐invariant. The human TOL/XYL mixture PBPK model, developed based on the quantitative biochemical mechanism of interaction elucidated in the rat (i.e., competitive metabolic inhibition), simulated adequately the kinetics of TOL and XYL during combined exposures in humans. The simulations with this PBPK model indicate that an eight hour co‐exposure to concentrations that remain within the current threshold limit values of TOL (50 ppm) and XYL (100 ppm) would not result in significant pharmacokinetic interferences, thus implying that data on biological monitoring of worker exposure to these solvents would be unaffected during co‐ex

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Uptake of chloroform into hairless rat stratum corneum from dilute aqueous solutions was studied using tape‐stripping to determine amounts deposited in the skin under various environmental exposure scenarios. The length of exposure of sedated animals to the chloroform‐containing medium, the frequency and duration of tape‐stripping, and the number of tape‐strips per location were varied to map the stratum corneum substantivity of chloroform. Eight minutes immersion of the rat within a well‐stirred solution at 36°C was found to be adequate time for the gradient to be established fully across the stratum corneum. Penetration was progressively deeper as the exposure time increased. Substantial evaporative loss of chloroform from the aqueous medium of application seem to be responsible for lower cumulative amounts taken up when the same solution was held on the rat's skin within a stainless steel template of fixed area. Of the total uptake (29 mg) from a dilute stirred solution of chloroform (0.44 mg/ml) at 36°C, about 95% was systematically absorbed after a 30 min exposure as determined by residuals (measurement of bath conc

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00327.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The present regulation of carcinogens is quite slow; hundreds of substances that have tested positive for carcinogenicity in animal bioassays have not been addressed by the U.S. regulatory system. This carries with it unappreciated social, economic, and public health costs. However, there are readily available expedited approximation procedures for assessing the potency of carcinogens whose use has substantial benefits that outweigh any costs from less science‐intensive and less extensively documented assessments. These benefits can be seen by using a model to suggest the magnitude of social costs in regulating carcinogens by current conventional methods compared with expedited procedures for assessing the potency of known carcinogens. Two scenarios, one in accordance with current agency presumptions and one which assumes extreme unreliability in animal data and in the accuracy of potency assessments, compare conventional science‐intensive and expedited procedures. On both, the total social costs of expedited procedures are lower than conventional procedures across a wide range of values assigned for individual mistakes of under regulation and over regulation. It appears better to evaluate a larger universe of known carcinogens somewhat less intensively for each substance than to evaluate a small proportion of that same universe very carefully and delay considering the r

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The traditional multistage (MS) model of carcinogenesis implies several empirically testable properties for dose‐response functions. These include convex (linear or upward‐curving) cumulative hazards as a function of dose; symmetric effects on lifetime tumor probability of transition rates at different stages; cumulative hazard functions that increase without bound as stage‐specific transition rates increase without bound; and identical tumor probabilities for individuals with identical parameters and exposures. However, for at least some chemicals, cumulative hazards are not convex functions of dose. This paper shows that none of these predicted properties is implied by the mechanistic assumptions of the MS model itself. Instead, they arise from the simplifying “rare‐tumor” approximations made in the usual mathematical analysis of the model. An alternative exact probabilistic analysis of the MS model with only two stages is presented, both for the usual case where a carcinogen acts on both stages simultaneously, and also for idealized initiation‐promotion experiments in which one stage at a time is affected. The exact two‐stage model successfully fits bioassay data for chemicals (e.g., 1,3‐butadiene) with concave cumulative hazard functions that are not well‐described by the traditional MS model. Qualitative properties of the exact two‐stage model are described and illustrated by least‐squares fits to several real datasets. The major contribution is to show that properties of the traditional MS model family that appear to be inconsistent with empirical data for some chemicals can be explained easily if an exact, rather than an approximate model, is used. This suggests that it may be worth using the exact model in cases where tumor rates are not negligible (e.g., in which they exceed 10%). This includes the majority of bioassay experiments cu

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00329.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

We gathered information on the cost‐effectiveness of life‐saving interventions in the United States from publicly available economic analyses. “Life‐saving interventions” were defined as any behavioral and/or technological strategy that reduces the probability of premature death among a specified target population. We defined cost‐effectiveness as the net resource costs of an intervention per year of life saved. To improve the comparability of cost‐effectiveness ratios arrived at with diverse methods, we established fixed definitional goals and revised published estimates, when necessary and feasible, to meet these goals. The 587 interventions identified ranged from those that save more resources than they cost, to those costing more than 10 billion dollars per year of life saved. Overall, the median intervention costs $42,000 per life‐year saved. The median medical intervention costs $19,000/life‐year; injury reduction $48,000/life‐year; and toxin control $2,800,000/life‐year. Cost/life‐year ratios and bibliographic references for more than 500 life‐saving i

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

This study examined to what extent nuclear risk perceptions, organizational commitment (OC), and appraisals of management are associated with each other among nuclear power plant personnel. The sample consisted of 428 nuclear power plant workers who completed a questionnaire at their workplace. Perceived nuclear risk and OC were most closely related to the appraisals of the top management of the organization. As the trust in and satisfaction with the top management increased, perceived nuclear safety and acceptance of the organizational goals and values heightened. This result is discussed in the context of industrial safety management.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1995.tb00331.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY