• Safety and Health at Work
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• v.12 no.4
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• pp.471-478
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• 2021

Background: Employment standards (ES) include having a regular payday, regular breaks, the right to paid sick or vacation time, and paid wages. Inadequate ES contribute to the labour market vulnerability of workers; however, they are not typically considered to be risk factors for workplace injury. In a sample of Canadian workers, we examine the risk of injury associated with inadequate ES, independent of, and combined with inadequate workplace protections from workplace hazards. Methods: Data from 2,803 adults working 15 hours or more/week in workplaces with at least five employees were analysed. We explored associations between exposure to workplace hazards with inadequate protections [termed occupational health and safety (OHS) vulnerability] and inadequate ES on workplace injury (physical or mental injury; injury requiring time off). Additive interaction models were used to examine the independent and combined effects of these exposures. Results: Occupational health and safety vulnerability and inadequate ES were independently associated with increased injury outcomes. Adjusted models showed an additive relationship for all injury outcomes between OHS vulnerability and inadequate ES. Statistically significant superadditive relationships were observed for physical injury risk with policy and procedure vulnerability plus inadequate ES [synergy index (S) 1.50, 95% CI: 1.13-2.00] and for overall OHS vulnerability plus inadequate ES (S 1.53, 95% CI: 1.16-2.02), suggesting a combined effect greater than independent effects. Conclusion: Occupational health and safety vulnerability and inadequate ES are independently associated with workplace injury. For certain injury outcomes, the combined effect of OHS vulnerability and inadequate ES is greater than the independent effects of each individual exposure.

• Journal of Environmental Science International
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• v.30 no.11
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• pp.945-956
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• 2021

In this study, the effects of single and binary heavy metals toxicity on the growth and phosphorus removal ability of Bacillus sp.. known as be a phosphorus-removing microorganism, were quantitatively evaluated. Cd, Cu, Zn, Pb, Ni were used as heavy metals. As a result of analysis of variance of the half of inhibition concentration and half of effective concentration for each single heavy metal treatment group, the inhibitory effect on the growth of Bacillus sp. was Ni < Pb < Zn < Cu < Cd. And the inhibitory effect on phosphorus removal by Bacillus sp. was Ni < Pb < Zn < Cu < Cd. When analyzing the correlation between growth inhibition and phosphorus removal efficiency of a single heavy metal treatment group, a negative correlation was found (R² = 0.815), and a positive correlation was found when the correlation between IC₅₀ and EC₅₀ was analyzed (R² = 0.959). In all binary heavy metal treatment groups, the interaction was an antagonistic effect when evaluated using the additive toxicity index method. This paper is considered to be basic data on the toxic effects of heavy metals when phosphorus is removed using phosphorus removal microorganisms in wastewater.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.128-133
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• 2024

Although antisolvent-assisted crystallization is one of the promising processes to produce high-quality perovskite films, general antisolvents such as chlorobenzene (CB) have toxic and volatile properties. In addition, CB is not suitable to control the crystallization of perovskite in the atmospheric air. In this work, isopropyl acetate (IA) is used as an eco-friendly antisolvent to demonstrate air-processed perovskite solar cells, and ethyl-4-cyanocinnamate (E4CN) with a cyano group, carbonyl group, and aromatic ring is introduced in IA to improve the performance and stability of devices. Defects at the surface and grain boundaries of the perovskite layer, such as un-coordinated Pb²⁺ and iodine, can be decreased resulting from the interaction of E4CN and perovskite, and thus reduced recombination and enhanced carrier transport can be expected. As a result, the perovskite device with E4CN achieves a high maximum power conversion efficiency (PCE) of 18.89% and outstanding stability, maintaining 60% of the initial efficiency for 300 h in the air without any encapsulation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.17-24
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• 2020

In this study, series of nonlinear seismic analysis were performed on a reinforced concrete intake tower surrounded by water. To consider the fluid effect around the structure, analysis models were composed using an added mass and CEL approach. At this time, the implicit method was used for the added mass model, and the explicit method was used for the fluid structure interaction model. The input motions were scaled to correspond to 500, 1000, and 2400 years return period of the same artificial earthquake. To estimate the counteractivity of the fluid coupled model, models without fluid effect were constructed and used as a reference. The material models of concrete and reinforcement were selected to consider the nonlinear behavior after yielding, and analysis were performed by ABAQUS. As results, in the acceleration response spectrum of the structure, it was found that the influence of the surrounding fluid reducing the peak frequency and magnitude corresponding to the fundamental frequency of the structure. However, the added mass model did not affect the peak value corresponding to the higher mode. The sectional moments were increased significantly in the case of the added mass model than those of the reference model. Especially, this amplification occurred largely for a small-sized earthquake response in which linear behavior is dominant. In the fluid structure interaction model, the sectional moment with a low frequency component amplifies compared to that of the reference model, but the sectional moment with a high requency component was not amplified. Based in these results, it was evaluated that the counteractivity of the additive mass model was greater than that of the fluid structure interaction model.

• Korean Journal of Environmental Agriculture
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• v.35 no.4
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• pp.241-246
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• 2016

BACKGROUND: Recently, the widespread distribution of pesticides in the hive has been of concern about pesticide exposure on honeybee (Apis mellifera L.) health. Larval toxicity was adapted to assess the synergistic and antagonistic interaction of cumulative mortality to the honeybee larvae of the four most common pesticides detected in pollen. METHODS AND RESULTS: Acetamiprid($3.0{\mu}l/L$), chlorothalonil ($803.0{\mu}l/L$), coumaphos ($128.0{\mu}l/L$), and tau-fluvalinate ($123.0{\mu}l/L$) were tested in combination; binary, ternary and four component mixture. Larvae were exposed to four pesticides mixed in diet at the average levels detected in pollen. As a result, synthetic toxicity was observed in the binary mixture of acetamiprid with coumaphos. The binary and ternary component mixtures of tested pesticides have mostly demonstrated additive effect in larval bees. The significant antagonistic effects were found in four parings of mixtures including chlorothalonil added to acetamiprid/tau-fluvalinate or acetamiprid/coumaphos/tau-fluvalinate, and tau-fluvalinate added to acetamiprid/chlorothalonil or acetamiprid/coumaphos/chlorothalonil. CONCLUSION: Interactions between combinations of four pesticides showed mostly additive or antagonistic effects in larval bees. Therefore, predicting the larval mortality of pesticides mixtures on the basis of the results of single pesticide may actually overestimate the risk. We suggest that pesticide mixture in pollen be evaluated by adding their toxicity together for complete data on interactions.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.154-160
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• 1998

This study was conducted to develop a foliar applied herbicide mixture covering wide spectrum weeds in dry direct seeded rice. Uniform precision central composite design(UPCCD) was employed to evaluate the effect of herbicide mixture among cyhalofop-butyl(cyhalofop), bispyribenzoxim and pyrazosulfuron-ethyl(pyrazosulfuron) having different weed control spectrum and to determine the best application rates of the three herbicide mixtures. The partial additive effect was observed in the mixture of cyhalofop and bispyribenzoxim with pyrazosulfron against Echinochloa crus-galli Beauv var crus-galli L., attributed to the negative interaction between cyhalofop and bispyribenzoxim system. Additive effect was observed in the mixture of bispyribenzoxim and pyrazosulfuron against Cyperus serotinus R. and Aneilema keisak H. but cyhalofop had no effect on these weeds. The most appropriate rate of the mixture of cyhalofop with bispyribenzoxim and pyrazosulfuron was 100 : 12 : 10g ai/ha exhibiting $ED_{90}$ against three weeds such as E. crus-galli, C. serotinus and A. keisak.

• Journal of Environmental Health Sciences
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• v.49 no.2
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• pp.89-98
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• 2023

Background: Organophosphorus flame retardants (OPFRs) are a group of chemical substances used in building materials and plastic products to suppress or mitigate the combustion of materials. Although OPFRs are generally used in mixed form, information on their mixture toxicity is quite scarce. Objectives: This study aims to elucidate the toxicity and determine the types of interaction (e.g., synergistic, additive, and antagonistic effect) of OPFRs mixtures. Methods: Nine organophosphorus flame retardants, including TEHP (tris(2-ethylhexyl) phosphate) and TDCPP (tris(1,3-dichloro-2-propyl) phosphate), were selected based on indoor dust measurement data in South Korea. Nine OPFRs were exposed to the luminescent bacteria Aliivibrio fischeri for 30 minutes and the human hepatocyte cell line HepG2 for 48 hours. Chemicals with significant toxicity were only used for mixture toxicity tests in HepG2. In addition, the observed EC_x values were compared with the predicted toxicity values in the CA (concentration addition) prediction model, and the MDR (model deviation ratio) was calculated to determine the type of interaction. Results: Only four chemicals showed significant toxicity in the luminescent bacteria assays. However, EC₅₀ values were derived for seven out of nine OPFRs in the HepG2 assays. In the HepG2 assays, the highest to lowest EC₅₀ were in the order of the molecular weight of the target chemicals. In the further mixture tests, most binary mixtures show additive interactions except for the two combinations that have TPhP (triphenyl phosphate), i.e., TPhP and TDCPP, and TPhP and TBOEP (tris(2-butoxyethyl) phosphate). Conclusions: Our data shows OPFR mixtures usually have additivity; however, more research is needed to find out the reason for the synergistic effect of TPhP. Also, the mixture experimental dataset can be used as a training and validation set for developing the mixture toxicity prediction model as a further step.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.129-135
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• 2017

Objectives : Little is known about the influence of urinary incontinence and depression on individual's QOL(Quality of life). We aimed to clarify how the interaction between urinary incontinence and depression influences one's QOL. Methods : A total of 1262 patients were enrolled in this study from April, 2011 to July, 2011. We estimated the severity of depressive symptoms and QOL, using SGDS-K, EQ-5D. We also investigated the morbidity of urinary incontinence for each patient in person or by questionnaire. Comparisons of QOL between groups with or without depression, with or without urinary incontinence were established using t-test, ANOVA and Scheffe's post hoc analysis. The interaction between urinary incontinence and depression was analyzed by each domain of QOL, using multiple regression analysis. Results : Patients with depression and urinary incontinence showed significantly higher EQ-5D scores on every domain of QOL than other patients, which means significantly lower QOL. Patients with depression, no urinary incontinence reported lower QOL, especially in the domain of 'usual activity', 'anxiety' and 'visual analogue scale(VAS)', whereas those with urinary incontinence, no depression showed lower QOL in 'motility', 'usual activities' and 'pain' domain. Statistically significant interaction effects of two diseases were observed in the domain of 'VAS', 'self care' and 'anxiety'. Conclusions : Comorbidity of urinary incontinence and depression showed significantly lower QOL of patients, compared with urinary incontinence or depression respectively, which implies additive interaction effects of the two diseases. Optimal diagnosis and treatment of depression should be emphasized for patients with urinary incontinence.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.81-88
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• 2002

The objective of this study was to investigate the line-by-feed additive interaction on egg traits and yolk cholesterol level in laying hens. Hy-line W-98 (white shell line) and Hy-line Brown (brown shell line) were used as experimental stocks and three groups were assigned in each line. The age of hens used in this study were from 40- to 46-wk-old. Two different levels of chitosan were also used as additive in chicken diet. The first (CH$_{30}$) and second (CH$_{60}$) experimental groups were fed basal diet added 30mg and 60mg chitosan/kg feed, respectively. And the control group (CON) hens were fed with basal diet only. The eggs were collected and analyzed at the end of 40, 42, 44, and 46-wk-old. In the mean egg weight, the CH$_{30}$ in Hy-line Brown was significantly heavier (P<0.05) than CON, but the CH$_{30}$ in Hy-line W-98 was significantly lighter (P<0.05) than CON. Whereas, the mean egg weight did not significantly differ between CH$_{60}$ and CON in both line. The mean albumen percentage in Hy-line Brown did not show significant between experimental groups and control group. On the other hand, the mean albumen percentage of CH$_{60}$ in Hy-line W-98 was significantly lower (P < 0.05) than that of CON, but there was no significantly different between CH$_{30}$ and CON. In the mean yolk percentage, it showed a reverse trend as shown in the mean albumen percentage; there were significantly higher (P<0.05) in CH$_{60}$ than in CON fur the Hy-line W-98, and higher in CH$_{30}$ than in CON for the Hy-line Brown. However, the mean shell percentages did not significantly differ between experimental groups and control group in both lines. In the mean yolk cholesterol levels, the CH$_{30}$ and CH$_{60}$ in both lines were lower by 0.46 mg ∼2.80 mg per gram yolk than CON. Although the interaction effect of line-by-supplementing level of chitosan in hens diet on the pooled mean of yolk cholesterol level was no significant, it showed a highly significant interaction (P<0.01) at three of four experimental ages.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.183-188
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• 2012

To investigate the influence of the prolactin receptor 3 (PRLR3) gene and the retinol-binding protein 4 (RBP4) gene on the production traits of swine, genotyping was performed on 156 and 141 Berkshire pigs, respectively, that were carefully selected for economic traits. The frequencies of allele A in the PRLR3 locus and allele B in the RBP4 locus were 0.50 and 0.42, respectively. Neither locus was in the Hardy-Weinberg equilibrium. After a genotype was assigned to the individuals whose parents had the homozygous genotype, a statistical analysis was conducted for 291 pigs. The animals with the PRLR3 and RBP4 genotypes included 182 and 227 head, respectively. Even though the genotypic effects of PRLR3 (p<0.05) and RBP4 (p<0.01) had a significant influence on the pigs' back fat thickness, the interaction of both genes was not highly significant in terms of the back fat thickness (p = 0.1235). While the estimated epistasis effects of aaBB and aaBb decreased the back fat thickness and reduced the growth rate, the effects of AAbb and aabb increased the growth rate. Despite the insignificant difference in the PRLR genotypes in terms of the days to 90 kg and the average daily gain, the back fat thickness showed a significant difference (p<0.05), and the additive effect of allele A and the dominant effect of the hetero-genotype were -0.377 and 1.206 mm, respectively. The RBP4 genotypes had a very significant effect (p<0.01) on the back fat thickness, the days to 90 kg, and the average daily gain. The additive effects of allele B of the RBP4 locus on the back fat thickness, the days to 90 kg, and the average daily gain were 0.70 mm, -1.3 days and 6.2 g, respectively. Moreover, the dominant effects of the heterozygote for those traits were 0.63 mm, 9.9 days and -45.0 g, respectively. Allele A of the PRLR3 locus favorably influenced the back fat thickness, the days to 90 kg of the body weight, and the average daily gain and its dominant effect unfavorably influenced those traits. Allele B of RBP4 showed an incremental growth rate and back fat thickness, which could lower the lean meat percentage in the carcass. The RBP4 hetero-genotype negatively affected the pork production. These results strongly imply that the selection of allele A of PRLR3 and allele B of RBP4 would produce highly productive pigs in the Berkshire breed. Careful selection of allele B of RBP4 is required because of the increase in the back fat thickness.