• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.421-422
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• 2004

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.6-15
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• 2024

Background: People's activities have been restricted due to the COVID-19 pandemic. These changes in activity patterns may lead to a decrease in fine particulate matter (PM_2.5) concentrations. Additionally, the level of population exposure to PM_2.5 may be changed. Objectives: This study aimed to analyze the impact of population movement and meteorological factors on the distribution of PM_2.5 concentrations before and after the outbreak of COVID-19. Methods: The study area was Guro-gu in Seoul. The research period was selected as January to March 2020, a period of significant population movement changes caused by COVID-19. The evaluation of the dynamic population was conducted by calculating the absolute difference in population numbers between consecutive hours and comparing them to determine the daily average. Ambient PM_2.5 concentrations were estimated for each grid using ordinary kriging in Python. For the population exposure assessment, the population-weighted average concentration was calculated by determining the indoor to outdoor population for each grid and applying the indoor to outdoor ratio to the ambient PM_2.5 concentration. To assess the factors influencing changes in the ambient PM_2.5 concentration, a statistical analysis was conducted, incorporating population mobility and meteorological factors. Results: Through statistical analysis, the correlation between ambient PM_2.5 concentration and population movement was positive on both weekends and weekdays (r=0.71, r=0.266). The results confirmed that most of the relationships were positive, suggesting that a decrease in human activity can lead to a decrease in PM_2.5 concentrations. In addition, when population-weighted concentration averages were calculated and the exposure level of the population group was compared before and after the COVID-19 outbreak, the proportion of people exceeding the air quality standard decreased by approximately 15.5%. Conclusions: Human activities can impact ambient concentrations of PM_2.5, potentially altering the levels of PM_2.5 exposure in the population.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.55-65
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• 2017

Average concentration of PM in Seoul metropolitan area satisfied the Korean air quality standard in 2010. Furthermore, concentration of PM in all boroughs across Seoul met the air environment standard in 2012. $PM_{10}$ concentration was relatively higher in center of Seoul in comparison to the rest, while $PM_{2.5}$ concentration showed exactly the contrary result. We analyzed the effect that PM emissions from vehicles would have on PM concentrations across Seoul. The results showed that average annual PM concentration recently decreased in Seoul although the number of vehicles registered annually continued its upward trend. By contrast, average fine dust concentrations in Seoul showed a decline which suggested that correlation between annual average PM concentrations and number of registered vehicles remained low. However, year-on-year vehicle registration rate recently showed a declining tendency in the same way as the trend of changes in average PM concentrations. Particularly, the upward trend in annual average PM concentrations in 2002 and 2007 was consistent with the increase in vehicle registration rate, suggesting that vehicle registration rate was closely associated with changes in PM concentrations.

• Asian Journal of Atmospheric Environment
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• v.9 no.4
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• pp.280-287
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• 2015

The high time-resolution monitoring data are essential to estimate rapid changes in chemical compositions, concentrations, formation mechanisms, and likely sources of atmospheric particulate matter (PM). In this study, $PM_{2.5}$ sulfate, $PM_{2.5}$, $PM_{10}$, and the number concentration of size-resolved PMs were monitored in Fukuoka, Japan by good time-resolved methods during the springtime. The highest monthly average $PM_{2.5}$ sulfate was found in May ($8.85{\mu}g\;m^{-3}$), followed by April ($8.36{\mu}g\;m^{-3}$), March ($8.13{\mu}g\;m^{-3}$), and June ($7.22{\mu}g\;m^{-3}$). The cases exceed the Japanese central government's safety standard for $PM_{2.5}$ ($35{\mu}g\;m^{-3}$) reached 10.11% during four months campaign. The fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ varied from 12.05% to 68.11% with average value of 35.49% throughout the entire period of monitoring. This high proportion of sulfate in $PM_{2.5}$ is an obvious characteristic of the ambient $PM_{2.5}$ in Fukuoka during the springtime. However, the average fraction of $PM_{2.5}$ sulfate to $PM_{2.5}$ in three rain events occurred during our intensive campaign fell right down to 15.53%. Unusually high $PM_{2.5}$ sulfate (> $30{\mu}g\;m^{-3}$) marked on three days were probably affected by the air parcels coming from the Chinese continent, the natural sulfur in the remote marine atmosphere, and a large number of ships sailing on the nearby sea. The theoretical number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ was originally calculated and then compared to $PM_{2.5}$ sulfate. A close resemblance between the diurnal variations of the theoretically calculated number concentration of $(NH_4)_2SO_4$ in $PM_{0.5-0.3}$ and $PM_{2.5}$ sulfate concentration indicates that the secondary formed $(NH_4)_2SO_4$ was the primary form of sulfate in $PM_{2.5}$ during our monitoring period.

• Korean Journal of Animal Reproduction
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• v.21 no.4
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• pp.363-371
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• 1997

The present study was carried out to investigate the effect of gonadotropin administration on blood ovarian steroid hormone in angora rabbit. Mature angora rabbits were primed for superovulation with PMSG 100IU. Eighty hours later, the rabbit were induced to ovulate with HCG 100IU. In exp 1, blood progesterone and estradiol of superovulated does were measured by radiommunoassay. Blood progesterone concentration at 93, 99, 102 and 114 hours after HCG injection were 12.9$\pm$0.5, 34.8$\pm$5.1, 12.2$\pm$2.7 and 43.4$\pm$5.8ng/ml, respectively. Mean progesterone concentration of blood collected at 99 and 114 hours after HCG injection(p<0.05). However, mean blood estradiol concentration was not changed. In exp 2, superovulated does were unilaterally ovariectomized at 96 hours after HCG injection. Blood progesterone concentration was tend to be decreased after ovariectomy. Nosignificant changes in blood estradiol concentration was observed after ovariectomy. In exp 3, superovulated does were bilaterally ovariectomized at 96 hours after HCG injection Ovariectomized does were treated with progesterone. Blood progesterone level in the rabbits treated, twice daily, with 5mg progesterone after ovariectomy was similiar to that in the superovulated intact rabbits. Blood estradiol concentration of the rabbits after bilateral ovariectomy was beyond detection range. Blood progesterone concentration was significantly decreased to 7.6$\pm$3.0ng/ml wi thin 3 hours after ovriectomy(p<0.05). However, that value was increased to 34.8$\pm$8.2ng/ml by 5 mg progesterone treatment and this elevated level was significatnly decreased to 7.3$\pm$2.4ng/ml at 12 hours after progesterone administration(p<0.05).

• Korean Journal of Veterinary Service
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• v.25 no.2
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• pp.141-151
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• 2002

In order to know the depletive changes of sulfadimethoxine and oxytetracycline residues in se겨m of dairy cattle intramusculally administered with sulfadimethoxine sodium(SDS) and oxytetracycline(OTC), the concentration of sulfadimethoxine and oxyteracycline was measured in serum of dairy cattle with using high performance liquid chromatography(HPLC). SDS and OTC was intramuscularlly administrated to dairy cattle at the rate of 10mg/kg(SDS) and 10mg/kg(OTC) body weight(recommended therapeutic dose) once to four dairy cattle. There were investigated the depletive changes of the sulfadimethoxine and oxytetracycline in serum of dairy cattle at the time 2, 4, 8 hours, 1st, 2nd, 3rd, 4th and 5th day after administration SMS and OTC, respectively. The results obtained were summarized as follows; 1. After intramuscularlly administration of the SMS, the mean concentrations of sulfamethazine in serum according to the time lapsed were showed 33.964 $\pm$ 4.435ppm at the 4 hours after withdrawal of medicated sulfadimethoxine sodium. And gradually according to the time lapsed, the concentrations of sulfadimethoxine residues in serum were significantly (p<.05) decreased 6.596 $\pm$ 3.402 ppm at 1st day, 0.217 $\pm$ 0.119 ppm at 3rd day and 0.057 $\pm$ 0.032 ppm at 4th day, respectively. 2. The mean residual concentration of OTC in serum according to the time lapsed after intramuscularly administration OTC were showed 0.743 $\pm$ 0.368ppm at the 8 hours. And gradually according to the time lapsed, the mean concentrations of OTC residues in serum of dairy cattle were significantly(p<.05) decreased such as 0.057 $\pm$ 0.047ppm at 3rd day and 0.039 $\pm$ 0.016ppm at the 5th day, respectively. In conclusion, this study could be suggested the relationship between administrated period, sulfonamides and tetracycline residual aspects in serum, and the importance of observing ceasing period of antibiotic drugs before forwarding livestocks to slaughter, Thus, this results would be able to be used the basic index for prevention of sulfonamides and tetracycline residues in dairy breedings.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.16-24
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• 2024

Background: Indoor PM_2.5 concentrations in residential houses can be affected by various factors depending on the season. This is because not only do the climate characteristics depend on the season, but the activity patterns of occupants are also different. Objectives: The purpose of this study is to compare factors affecting indoor PM_2.5 concentrations in apartments and detached houses in Daegu according to seasonal changes. Methods: This study included 20 households in Daegu, South Korea. The study was conducted during the summer (from July 10 to August 10, 2023) and the autumn (from September 11 to October 9, 2023). A sensor-based instrument for PM_2.5 levels was installed in the living room of each residence, and measurements were taken continuously for 24 hours at intervals of one minute during the measurement period. Based on the air quality monitoring system data in Daegu, outdoor PM_2.5 concentrations were estimated using ordinary kriging (OK) in Python. In addition, the indoor activities of the occupants were investigated using a time-activity pattern diary. The affecting factors of indoor PM_2.5 concentration were analyzed using multiple regression analysis. Results: Indoor and outdoor PM_2.5 concentrations of the residences during summer were 15.27±11.09 ㎍/m³ and 11.52±7.56 ㎍/m³, respectively. Indoor and outdoor PM_2.5 concentrations during autumn were 13.82±9.61 ㎍/m³ and 9.57±5.50 ㎍/m³, respectively. The PM_2.5 concentrations were higher in summer compared to autumn both indoors and outdoors. The primary factor affecting indoor PM_2.5 concentration in summer was occupant activity. On the other hand, during the autumn season, the primary affecting factor was outdoor PM_2.5 concentration. Conclusions: Indoor PM_2.5 concentration in residential houses is affected by occupant activity such as the inflow of outdoor PM_2.5 concentration, cooking, and cleaning, as found in previous studies. However, it was revealed that there were differences depending on the season.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1677-1683
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• 2007

Physiological changes in thoroughbred racehorses during the race were investigated by measuring concentrations of metabolites and exercise-related hormones before and after a race. The conversion point from anaerobic to aerobic exercise during the race was estimated subsequently. Blood samples were taken from the jugular vein of 53 thoroughbreds at different times -three h before and 45 min after- for measuring the concentrations of glucose, non-esterified fatty acids (NEFA), lactate, uric acid, ammonia, insulin, adrenocorticotrophin (ACTH) and cortisol according to the race distance. In accordance with the race distance, each metabolite increased in concentration compared with the level before the race. The level of glucose, in particular, increased from $56.18{\pm}3.20$ mg/dl before the race to $148.82{\pm}8.82$ mg/dl after the race for horses that raced 1,400 m, showing a significant increase of 165% (p<0.001). The concentration of NEFA rose from $76.77{\pm}5.59$ uEq/L to $335.85{\pm}35.39$ uEq/L, up 337% (p<0.01) after a 1,400 m race. Exercise-related hormones also showed similar changes. The level of insulin dropped the most in horses that raced 1,400 m, by 42%, from $0.97{\pm}0.18$ to $0.56{\pm}0.05\;{\mu}g/L$ (p<0.5); however, ACTH and cortisol jumped significantly at 1,800 m, from $20.17{\pm}2.12$ to $551.45{\pm}91.33$ pg/ml (p<0.5) and $1.13{\pm}0.16$ to $5.66{\pm}0.45\;{\mu}g/dl$ (p<0.01), respectively, representing the highest increase. Therefore, based on the changes in glucose, NEFA and insulin levels before and after the race, it was concluded that the race distance of 1,400 m represents the point where racehorses make a conversion from anaerobic to aerobic exercise.

• Journal of Environmental Health Sciences
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• v.49 no.6
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• pp.362-371
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• 2023

Background: PM_2.5 pollution has been a persistent problem in South Korea, with concentrations consistently exceeding World Health Organization (WHO) guidelines. The aging of the population in the country further exacerbates the health impacts of PM_2.5 since older adults are more susceptible to the adverse effects of air pollution. Objectives: This study aims to evaluate how the health impact (premature death) due to long-term exposure to PM_2.5 in South Korea could change in the future according to the trend of change in the country's population structure. Methods: The study employs a relative risk function, which accounts for age-specific relative risks, to assess the changes in premature deaths by age and region at the average annual PM_2.5 concentration for 2022 and at PM_2.5 concentration improvement levels. Premature deaths were estimated using the Global Exposure Mortality Model (GEMM). Results: The findings indicate that the increase in premature deaths resulting from the projected population structure changes up to 2050 would significantly outweigh the health benefits (reduction in premature deaths) compared to 2012. This is primarily attributed to the rising number of premature deaths among the elderly due to population aging. Furthermore, the study suggests that the effectiveness of the current domestic PM_2.5 standard would be halved by 2050 due to the increasing impact of population aging on PM_2.5-related mortality. Conclusions: The study highlights the importance of considering trends in population structure when evaluating the health benefits of air pollution reduction measures. By comparing and evaluating the health benefits in reflection of changes in population structure to the predicted PM_2.5 concentration improvements at the provincial level, a more comprehensive assessment of regional air quality management strategies can be achieved.

• Journal of Embryo Transfer
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• v.3 no.1
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• pp.24-30
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• 1988

This study was conducted to investigate the effect of unilateral ovariectomy on the embryo survival and changes of plasma progesterone and estradiol concentration. Mature Angora rabbits were divided into 2 groups (Superovulation and unilateral ovariectomy after superovulation). Unilateral ovariectomied rabilts were subdivided into two groups according to the time of ovariectomy (24 hours and 96 hours after mating). The results obtained were summarized as follows; 1. After unilateral ovariectomy, survival rate and collecting rate of embryos recovered from contralateral and ipsilateral oviduct and uterus were not different, and were lower than intact rabbits. 2. Plasma progesterone concentration at 93, 99, 102 and 114 hours after HCG injection in superovulated rabbits were 12.9 $\pm$ 0.5, 34.8 $\pm$ 5.1, 12.2 $\pm$ 2.7 and 43.4 $\pm$ 5.8ng/ml, respectively. Mean progesterone concentrations were significantly higher at 99 and 114 hours than at 93 and 102 hours (p <0.05). But plasma estradiol concentration was not different. 3. Plasma progesterone concentration in unilateral ovariectomized rabbits was somewhat decreased after unilateral ovariectomy. Plasma estradiol concentration was not different.