• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.3
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• pp.242-252
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• 2022

Objectives: Firefighters and police officers are exposed to various occupational hazards. No studies in Korea have investigated the occurrence of cancer by type of cancer for the two occupations. This study aims to investigate the risk of occurrences associated with types of cancers in firefighters and police officers. Methods: Utilizing National Health Insurance(NHI) Claims data from 2006-2015, the study included 8,871,468 general workers, 25,001 firefighters, and 102,274 police officers. Using general workers as a control group, we calculated the standardized incidence ratios(SIR) by types of cancer for firefighters and police officers. After calculating the SIR for all subjects, the SIR was calculated by stratifying according to gender. Results: SIR of colon cancer 1.38(95% CI, 1.11-1.69), cancer of the liver and intrahepatic bile ducts 1.27(95% CI, 1.04-1.54), and 1.88(95% CI, 1.28-2.65) bladder cancer were higher firefighters than general workers. SIR of Lip, oral cavity, and pharynx 1.26(95% CI, 1.07-1.47), Stomach 1.14(95% CI, 1.06-1.23), colon 1.33(95% CI, 1.21-1.46), liver and intrahepatic bile ducts 1.21(95% CI, 1.10-1.32), pancreas 1.24(95% CI, 1.02-1.49), other skin 1.60(95% CI, 1.26-2.00), bladder 1.27(95% CI, 1.04-1.54), other urinary tract 1.46(95% CI, 1.27-1.68), other parts of central nervous system 1.68(95% CI, 1.10-2.46) were higher police officers than general workers. Conclusions: Both firefighters and police officers are exposed to various cancer occurrence risks, necessitating the development of occupational medical protection measures to reduce risk exposure factors.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.41.1-41.11
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• 2023

Background: Shift work has been reported to have several harmful effects on the human body. However, a small number of studies have evaluated the association between shift work and adverse effects on the thyroid. In our longitudinal study, we examined the causal association between shift work and the risk of hypothyroidism. Methods: A Kangbuk Samsung Cohort Study was conducted on 112,648 men without thyroid disease at baseline who were followed up at least once between 2012 and 2019. Shift work status and shift schedule types were categorized using standardized questionnaires. Hypothyroidism was defined using the reference ranges of serum thyroid-stimulating hormones and free thyroxine levels. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident hypothyroidism were estimated using Cox proportional hazards regression analyses with the daytime work group as the reference. Results: During the 501,237 person-years of follow-up, there were 6,306 incident cases of hypothyroidism (incidence density, 1.26 per 100 person-years). The multivariable-adjusted HR of incident hypothyroidism for the shift work total group that included all shifts compared with the daytime work group was 1.27 (95% CI: 1.15-1.40). For the fixed evening, fixed night, rotating shift, and other shift workers, the multivariable-adjusted HRs (95% CI) were 1.11 (0.76-1.61), 2.18 (1.20-3.93), 1.39 (1.23-1.56), and 1.00 (0.82-1.22), respectively. In subgroup analyses by age, the association between shift work and hypothyroidism was more pronounced in younger participants (< 40 years; HR: 1.31; 95% CI: 1.16-1.47). Conclusions: Our large-scale cohort study showed an association between shift work and the incidence of hypothyroidism, especially in younger workers with night shifts.

• Journal of Nutrition and Health
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• v.57 no.2
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• pp.211-227
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• 2024

Introduction: Seaweed is a sustainable and underexplored source of bioactive compounds with potent anti-inflammatory activities. However, studies on the interaction between seaweed and genes on inflammation are limited. Purpose: We aimed to evaluate the relationships between seaweed consumption and the polygenic risk scores (PRS) and their interactions with high-sensitivity C-reactive protein (hs-CRP) levels. Methods: Information on seaweed consumption was collected using a food frequency questionnaire, which included laver, kelp, and sea mustard among the items consumed. A total of 31 hs-CRP-related single nucleotide polymorphisms (SNPs) were selected using genome-wide association studies and clumping analysis, and the individual PRS were calculated by weighting the effect size of each allele in the selected SNPs of 39,369 middle-aged (≥40 years) Koreans using the Korean Genome and Epidemiology Study (KoGES)-Health Examinees (HEXA) cohort data. To investigate the interaction between seaweed intake and the PRS on hs-CRP levels >1 mg/L, hazard ratios (HRs) and 95% confidence intervals (CIs) were assessed using multivariable Cox proportional hazards models. Results: During a mean follow-up period of 4.8 years, we recorded 436 patients with elevated hs-CRP levels. Women in the highest tertile of the PRS with the lowest quartile of seaweed intake had an increased incidence of elevated hs-CRP levels compared with women in the lowest tertile of the PRS with the lowest seaweed intake quartile (HR 2.34, 95% CI 1.23-4.45). No significant association was observed among the men. Conclusion: In conclusion, we identified a new interaction between the PRS, seaweed intake, and inflammation in Korean women, and this study suggests that the interaction between the identification of genetic predisposition and dietary seaweed intake may have an impact on determining the risk of developing hyperinflammation in the future.

• Geophysics and Geophysical Exploration
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• v.27 no.2
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• pp.91-107
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• 2024

Single-channel seismic exploration has proven effective in delineating subsurface geological structures using small-scale survey systems. The seismic data acquired through zero- or near-offset methods directly capture subsurface features along the vertical axis, facilitating the construction of corresponding seismic sections. However, substantial noise in single-channel seismic data hampers precise interpretation because of the low signal-to-noise ratio. This study introduces a novel approach that integrate noise reduction and signal enhancement via matrix rank optimization to address this issue. Unlike conventional rank-reduction methods, which retain selected singular values to mitigate random noise, our method optimizes the entire singular value spectrum, thus effectively tackling both random and erratic noises commonly found in environments with low signal-to-noise ratio. Additionally, to enhance the horizontal continuity of seismic events and mitigate signal loss during noise reduction, we introduced an adaptive weighting factor computed from the eigenimage of the seismic section. To access the robustness of the proposed method, we conducted numerical experiments using single-channel Sparker seismic data from the Chukchi Plateau in the Arctic Ocean. The results demonstrated that the seismic sections had significantly improved signal-to-noise ratios and minimal signal loss. These advancements hold promise for enhancing single-channel and high-resolution seismic surveys and aiding in the identification of marine development and submarine geological hazards in domestic coastal areas.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1781-1795
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• 2024

This study investigated the levels of radioactivity in soil surrounding a phosphate fertilizer factory in Egypt, aiming to assess potential risks to the population exposed to radiation. Concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K were measured in soil samples collected from two subsites: one near the factory (subsite 1) and another further away (subsite 2). Two different systems were used for measuring radioactivity, a high-purity gamma ray spectroscopy system with an HPGe detector for gamma-emitting isotopes and a CR-39 solid nuclear track detector for alpha-emitting radon gas. Subsite 1, located close to the factory, displayed significantly elevated levels of ²²⁶Ra compared to global background levels (514 and 456 Bq/kg vs. 35 Bq/kg). Additionally, the concentrations of ²³⁸U (241.06 Bq/kg vs. global average 35 Bq/kg), ²³²Th (16.15 Bq/kg vs. global average 30 Bq/kg), and ⁴⁰K (146.36 Bq/kg vs. global average 400 Bq/kg) were all above global averages. Furthermore, a high concentration of radon gas (337.06 μSv/y) was measured at subsite 1. The strong positive correlation observed between ²²⁶Ra and ²³⁸U (0.96256) provides further evidence of potentially elevated radioactivity levels near the factory. In contrast, subsite 2, situated farther from the factory, exhibited natural radioactive background levels within international limits. Quantitative analysis revealed that gamma ray absorbed doses for ²²⁶Ra and ²³²Th exceeded global averages in some samples. Specifically, ²²⁶Ra doses ranged from 7.8 to 46.26 ppm (exceeding the 20 ppm global average in some cases), and ²³²Th doses ranged from 1.98 to 9.14 ppm (exceeding the 10 ppm global average in some cases). The concentration of ⁴⁰K, however, remained within the global range (0.07%-0.69 %). The observed imbalances in the ratios of Th/U (0.17-0.24 Bq/kg and 0.73-0.24 ppm) and U/Ra (0.81-0.73 Bq/kg and 0.73-0.17 ppm), both of which are significantly lower than their respective global averages of 4 and 2.4, point towards the presence of fertilizer-derived contamination. This conclusion is further supported by the high phosphate concentrations detected in the samples. Overall, this study suggests that radioactive contamination near the phosphate fertilizer factory significantly exceeds global background levels and international limits in some cases. This raises concerns about potential risks posed to surrounding agricultural land and crops.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.317-324
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• 2007

Fluorescence measurements of dissolved organic matter(DOM) have the superior advantages over other analysis tools for applying to water quality management. A preliminary study was conducted to test the feasibility of applying synchronous fluorescence measurements for tracing and monitoring pollution sources in a small stream located in an upstream area of the Sooyoung watershed in Busan. The water quality of the small stream is affected by leachate from sawdust pile and discharge of untreated sewage. The sampling sites included an upstream site, two pipes discharging untreated sewage, leachate from sawdust, and a downstream site. Of the five field samples, the leachate was distinguished from the other samples by a high peak at a lower wavelength range and a blunt peak at 350nm, suggesting that synchronous fluorescence can be used as a discrimination tool for monitoring the pollution. The efficacy of various indices derived from the spectral features to discriminate the pollution source was tested for well-defined mixture of the sawdust leachate and the upstream stream by comparing (1)the difference between measured values and those predicted based on mass balance and the characteristics of the two samples and (2)the linear correlations between index values and mass ratios of the sample mixtures. Of various discrimination indices selected, fluorescence intensities at 276 nm$({\Delta}\lambda=30nm)$and 347 nm$({\Delta}\lambda=60nm)$ were suggested as promising potential discrimination indices for the sawdust pollution source. Despite the limited number of samples and the study area, this study illustrates the evaluation process that should be followed to develop rapid, low-cost discrimination indices to monitor pollution sources based on end member mixing analyses.