• Journal of Environmental Health Sciences
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• v.49 no.3
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• pp.129-133
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• 2023

Background: With the rise in global mobility, aircraft indoor air quality has become a significant public health concern. This study focuses on the health implications of increased travel and bleed air-air drawn from aircraft engines for cabin pressurization and air conditioning. Objectives: This research aims to review the potential health effects related to exposure to aircraft cabin air, particularly the effects of bleed air during fume events. Methods: We conducted a literature review of existing studies on aircraft cabin air quality. We focused on both the immediate and health effects of exposure to cabin air, particularly those related to bleed air contaminants. Results: The review found a possible link between exposure to aircraft cabin air and certain health issues, especially in cabin crew and frequent flyers. There was an increased incidence of respiratory and neurological symptoms related to bleed air exposure. However, the cumulative health effects of frequent air travel remain inconclusive due to limited data. Conclusions: This study highlights the need for improving air quality in aircraft to protect public health. While further research is needed to understand the cumulative effects of frequent air travel, the reduction of exposure to bleed air contaminants should be a priority. These findings underline the need for regulatory changes and technological improvements in aircraft cabin air quality.

• Safety and Health at Work
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• v.9 no.3
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• pp.290-295
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• 2018

Background: There is little information on the dose-response relationship between exposure to occupational carcinogenic agents and mesothelioma. This study aimed to investigate this association as well as the existence of agents other than asbestos that might cause mesothelioma. Methods: The Swedish component of the Nordic Occupational Cancer (NOCCA) study consists of 6.78 million individuals with detailed information on occupation. Mesothelioma diagnoses recorded in 1961-2009 were identified through linkage to the Swedish Cancer Registry. We determined cumulative exposure, time of first exposure, and maximum exposure intensity by linking data on occupation to the Swedish NOCCA job-exposure matrix, which includes 29 carcinogenic agents and corresponding exposure for 283 occupations. To assess the risk of mesothelioma, we used conditional logistic regression models to estimate hazard ratios and 95% confidence intervals. Results: 2,757 mesothelioma cases were identified in males, including 1,416 who were exposed to asbestos. Univariate analyses showed not only a significant excess risk for maximum exposure intensity, with a hazard ratio of 4.81 at exposure levels 1.25-2.0 fb/ml but also a clear dose-response effect for cumulative exposure with a 30-, 40-, and 50-year latency time. No convincing excess risk was revealed for any of the other carcinogenic agents included in the Swedish NOCCA job-exposure matrix. Conclusion: When considering asbestos exposure, past exposure, even for short periods, might be enough to cause mesothelioma of the pleura later in life.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.406-413
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• 2023

Captive breeding and reintroduction are crucial strategies for conserving endangered species populations. However, fish raised in predator-free environments, show a lack of recognition of predationrelated stimuli such as chemical and visual signals. It is critical to recognize chemical signals from injured conspecifics, also known as alarm signals, and the order or shape of predators to indicate the spread of predation risk in the habitat. We conducted a laboratory experiment to determine and adjust the optimal exposure period to induce appropriate anti-predator behavior response to different types of stimuli (Chemical, Visual and Chemical+Visual) for the endangered species Microphysogobio rapidus. Our results demonstrate that predator avoidance behavior varies depending on the types of stimuli and the duration of predation risk exposure. First, the results showed captive-breed M. rapidus show lack of response against conspecific alarm signal (Chemical cue) before the predation risk exposure period and tend to increase response over predation risk exposure time. Second, response to predator (visual cue) tend to peak at 48 hours cumulative exposure, but show dramatic decrease after 72 hours cumulative exposure. Finally, response to the mixed cue (Chemical+visual) tend to peak prior to the predation risk exposure period and show reduced response during subsequent exposure periods. This experiment confirms the lack of responsiveness to conspecific alarm signals in captive-bred M. rapidus and the need for an optimal nature behavior enhancement program prior to release of endangered species. Furthermore, responsiveness to predator visual signal peak at 48 hours cumulative exposure, suggest an optimal predation risk exposure period of up to 48 hours.

• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.165-171
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• 2009

Biomarkers indicating past exposure to radiation have not yet been entirely satisfactory. In this study, we validated several genes reported as radiation response genes, as biomarkers to detect past exposure to radiation in occupationally exposed workers, especially workers in the medical field. A total of 54 radiation workers in hospital were investigated for radiation exposure dose. Their average radiation dose of recent one year was 1.09 mSv ($\pm$1.63) with a 10.63 mSv ($\pm$12.91) cumulative dose. The results of the multiple regression analysis for the various variables indicate that the Hsc70 (P=0.0292) and ORAL (P=0.0045) may be candidate biomarkers for the recent 1 year radiation exposure in radiation workers, whereas AEN (P=0.0334) and PGAMI (P=0.0003) might be for cumulative exposure.

• Journal of the Korean Society of Child Welfare
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• no.26
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• pp.61-86
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• 2008

This Study examines the relationship between Cumulative Risk and Behavioral Problem of children's in divorced family. The cumulative risk was Summed for each children to creative an cumulative scores. Scores on the index ranged from 0 to 12. Cumulative Risk was associated with Behavioral Problem. Moreover the analyses revealed positive, linear associated between Cumulative Risk and Behavioral Problem. Cumulative Risk predicted Problem Behavioral of Divorced Family's Children. Finding indicate that the amount of risk in Divorced Family's childrens lives was useful for determining the extent to which cumulative risk exposure plays an etiological role in Behavioral Problem. On the basis of these results, this article provided some suggestions for promoting of children welfare.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.168-172
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• 2016

The effect of different exposed length of M.9 rootstock on growth and yield was tested in the new apple cultivars. The 'Seohong', 'Summer Dream', and 'Hongguem' grafted on M.9 rootstock were planted in March 2010. The trees were planted in such a way that the exposed length of the rootstock to be 10, 20 and 30 cm. The result showed that as decreasing exposure length, TCA of 'Seohong', 'Summer Dream', and 'Hongguem' was increased between $3^{rd}$ and $6^{th}$ year after planting. The TCA of 20 cm and 30 cm exposure length showed respectively 70% and 60% in 'Seohong', 88% and 66% in 'Summer Dream', and 55% and 41% in 'Hongguem' of the TCA with 10 cm exposure length on 6-year-old trees. Tree height, canopy width, shoot length and terminal shoot length were also increased according to decreased exposure length in 6-year-old trees. The cumulative yield of three cultivars was higher in the tree with a lower exposure length between $4^{th}$ and $6^{th}$ year after planting. The cumulative yield of 20 cm and 30 cm exposure length showed respectively 77% and 63% in 'Seohong', 85% and 76% in 'Summer Dream', and 73% and 58% in 'Hongguem' of the cumulative yield with 10 cm exposure length in 6-year-old trees. Considering tree growth and yield, the optimum exposure length of M.9 was 10 cm for 'Seohong', 'Summer Dream' and 'Hongguem'.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.136-141
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• 2004

The gear in various mechanical components easily occurs at damages by the external torque. The main failure modes of the gear are surface pitting with the tooth surface and breakage with tooth root by caused fatigue. Therefore, the gear is very important role in the reliability research since it may cause fatal damage of entire system such as the gear box in automobile transmission. In this study, the failure mode of the gear was analyzed and accelerated durability analysis was employed for the life estimation of spur gears. In the case of assumed load spectrums, the reliability of spur gears was evaluated by inverse power law-Weibull accelerated life test model with cumulative damage exposure.

• Communications for Statistical Applications and Methods
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• v.23 no.4
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• pp.269-285
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• 2016

In this paper, a simple step-stress accelerated life test (ALT) under progressive type-II censoring is considered. Progressive type-II censoring and accelerated life testing are provided to decrease the lifetime of testing and lower test expenses. The cumulative exposure model is assumed when the lifetime of test units follows an extension of the exponential distribution. Maximum likelihood estimates (MLEs) and Bayes estimates (BEs) of the model parameters are also obtained. In addition, a real dataset is analyzed to illustrate the proposed procedures. Approximate, bootstrap and credible confidence intervals (CIs) of the estimators are then derived. Finally, the accuracy of the MLEs and BEs for the model parameters is investigated through simulation studies.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.271-280
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• 2015

In this paper, the maximum likelihood estimators for parameters are derived under three step-stress accelerated life tests for Type-I hybrid censored data. The exponential distribution and the cumulative exposure model are considered based on the assumption that a log quadratic relationship exits between stress and the mean lifetime ${\theta}$. The test plan to search optimal stress change times minimizing the asymptotic variance of maximum likelihood estimators are presented. A numerical example to illustrate the proposed inferential procedures and some simulation results to investigate the sensitivity of the optimal stress change times by the guessed parameters are given.

• Journal of Environmental Health Sciences
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• v.36 no.4
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• pp.264-270
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• 2010

Agricultural workers are often exposed to high levels of dust during field operations. A systematic exposure assessment of annual task-weighted exposure has not been thoroughly examined. The occupational dust exposure in two wine grape vineyards was measured. Exposure levels to total and respirable dust were determined for a 1-year cycle of work. An operation profile including the frequency of tasks was established. The means of total and respirable dust exposure were $1.08\;mg/m^3$ and $0.07\;mg/m^3$, respectively. Based on the exposure for each task and the task frequency, task-weighted mean exposures to total and respirable dust were estimated as $1.115\;mg/m^3$ and $0.079\;mg/m^3$, respectively. The task-weighted exposure was significantly represented by three operations and could be attributed to the exposure frequency rather than the exposure intensity of operations. The measurement of a few of the most frequent tasks may be an alternative method of estimating task-weighted exposure. Agricultural dust exposure can be significantly reduced by targeting those tasks most important to task-weighted dust exposure.