• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.73-76
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• 2003

SF$_{6}$ (Sulfur Hexafluoride) is a gaseous compound whose use is being greatly increased recently. The compound has a negligible background concentration from natural sources and is stable in most of groundwater environments. Therefore, SF$_{6}$ has potential for a dating tool for young groundwater. It has many advantages over chlorofluorocarbons (CFCs) for groundwater investigation that sampling procedure is much simpler than CFCs and its growth is continued up to at least near future in the atmosphere. However, solubility of SF$^{6}$ is so low that excess air causes large uncertainties in recharge date of groundwater. To compensate the limitation, $N_2$/Ar method can be employed to estimate excess air content. A groundwater study is currently carrying out in Jeju Island using SF$_{6}$ as an environmental tracer, Well waters and spring waters were sampled for SF$_{6}$ and $N_2$/Ar. To establish SF$_{6}$ input history in the study area, air sampling is being conducted in the area near the center of the island on a monthly and weekly basis. Based on the present data, the level of SF$_{6}$ concentration in the atmosphere of the Island is corresponding to the trend of the Northern Hemisphere.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.677-687
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• 2017

Caffeine has a long history of human consumption but the consumption of caffeine due to caffeinated energy drinks(CEDs) is rapidly growing. Marketing targets of CED sales are children, adolescents and young adults, possibly caffeine-sensitive groups and its effect for them can be significantly different from healthy adults. Caffeine-related toxicities among these groups are growing in number and a number of countries are recognizing severity of caffeine toxicities. Previous research showed prediction of maximal plasma caffeine concentration profiles after the single CED ingestion and the primary aim of this study is to visually predict plasma caffeine concentration after the single and multiple ingestion of standard servings of CED. Based on the population pharmacokinetic model using Monte Carlo simulation, prediction of caffeine concentration leading to caffeine intoxication in the sensitive groups is quantitatively presented and visualized. This research also broadens the perspective by creating and utilizing diverse open science tools including R package, Edison Science App and Shiny apps.

• 세라미스트
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• 제22권4호
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• pp.357-367
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• 2019

Secondary Ion Mass Spectrometry(SIMS) is an analytical method that measures the distribution and concentration of elements or compounds by analyzing the mass of secondary ions released by irradiating ion beams with energy of hundreds eV to 20 keV on the sample surface. Unlike other similar analytical instruments, SIMS directly detect the elemental ions that constitute a sample, allowing you to accurately identify components and obtain concentration information in the depth direction. It is also a great feature for measuring isotopes and analyzing light elements, especially hydrogen. In particular, with the development of materials science, there is an increasing demand for trace concentration analysis and isotope measurements in the micro-regions of various materials. SIMS has a short history compared to other similar methods; nevertheless, SIMS is still advancing in hardware and is expected to contribute to the development of materials science through research and development of advanced analytical techniques.

• 한국터널지하공간학회 논문집
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• 제20권5호
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• pp.887-897
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• 2018

수직구와 수평 터널 주위 지층 변화, 지진파 방향성이 접속부의 동적 거동 특성에 미치는 영향을 연구하였다. 유한 요소 기반의 MIDAS GTS NX 프로그램을 이용한 3차원 시간이력 해석을 통해 검토하였다. 연구결과 연약지반에서 장주기의 지진파가 수평 터널 방향으로 발생하였을 때 접속부 상부에서 최대 변위가 발생하는 것으로 나타났다. 또한 수직구와 수평 터널의 서로 다른 거동 및 지층 경계면의 영향으로 인해 응력집중 현상이 발생하여 문제가 될 수 있음을 확인 할 수 있었다. 연구 결과는 수직구와 수평 터널의 접속부 구조물 내진설계를 위한 기초자료로 활용 될 수 있을 것으로 기대된다.

• Clinical and Experimental Reproductive Medicine
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• 제43권2호
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• pp.97-101
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• 2016

Objective: Growth hormone and its mediator, insulin-like growth factor-1 (IGF-1), have been suggested to exert gonadotropic actions in both humans and animals. The present study was conducted to assess the relationship between serum IGF-1 concentration, seminal plasma concentration, and sperm parameter abnormalities. Methods: A total of 79 men were enrolled in this study from December 2011 to July 2012 and were prospectively analyzed. Patient parameters analyzed included age, body mass index, smoking status, urological history, and fertility history. Patients were divided into four groups based on their semen parameters: normal (A, n=31), abnormal sperm motility (B, n=12), abnormal sperm morphology (C, n=20), and two or more abnormal parameters (D, n=16). Patient seminal plasma and serum IGF-1 concentrations were determined. Results: Patient baseline characteristics were not significantly different between any of the groups. The serum IGF-1 levels in groups B, C, and D were significantly lower than the levels in group A; however, the seminal plasma IGF-1 levels were not significantly different between any of the groups. Conclusion: Men with abnormal sperm parameters had significantly lower levels of serum IGF-1 compared with men with normal sperm parameters. Seminal plasma IGF-1 levels, however, did not differ significantly between the groups investigated here. Further investigations will be required to determine the exact mechanisms by which growth hormone and IGF-1 affect sperm quality.

• 천문학회보
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• 제27권1호
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• pp.36-36
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• 2002

별똥에는 가랑 별똥(sporadic meteors)과 별똥비 (meteor shower)에 속하는 별똥이 있다. 우리는 고려사 천문지에 적혀 있는 별똥 기록을 조사하여 10세기에서 15세기까지 지구 공전 궤도 상의 별똥 알갱이의 분포에 대해서 연구하였다. 우리는 일년중 특정한 날짜에 별똥이 많이 떨어지는 시기가 몇 개 있음을 발견하였다. 우리는 이러한 별똥들이 별똥비에 해당할 것으로 가정하고 한국, 일본, 중국의 천문 기록 가운데 별똥 소나기 기록을 끄집어 내어 고려사의 별똥 기록에서 구한 별똥비 기록과 비교하였다. 그 결과 7월 27일 경에 강한 별똥비가 있었고, 몇 년 주기로 별똥 소나기가 떨어졌음을 알아 냈다. 우리는 고려 시대의 별똥 기록을 두개로 나누어 별똥비의 세기가 어떤 진화를 하는지는 연구하였다. 7월 27일에 나타난 별똥비는 그 세기가 줄어든 것을 알 수 있었다.

• Journal of Preventive Medicine and Public Health
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• 제33권4호
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• pp.477-483
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• 2000

Objectives : To obtain reference values for the pulmonary asbestos and non-asbestos fiber contents of residents in Korea and to compare them with similar results from Japan. Methods : The autopsied lung specimens from 22 deceased people (20 males and 2 females) in Pohang, without any known occupational history of asbestos exposure, were analyzed for incidence of asbestos and non-asbestos fibers by transmission electron microscopy with energy dispersive X-ray analysis after using low temperature ashing procedures. Results : Chrysotite fiber (46.2%) was the major fiber type found in the lungs of the subjects. The asbestos fiber concentrations found in males and females were $0.09\times10^6$ fiberss(g of dry lungs) and $0.30\times10^6$ fibers/(g of dry lungs), respectively, showing a geometric mean concentration $0.09\times10^6$ fibers/(g of dry lung tissue), due to the predominance of males in the sample. The non-asbestos fiber contents in males and females were $4.61\times10^6$ fibers/(g of dry lungs) and $17.79\times10^6$ fibers/(g of dry lungs), respectively, with a geometric mean concentration $5.21\times10^6$ fibers/(g of dry lung tissue). Conclusions : Residents in Pohang had significantly lower levels of both asbestos and non-asbestos fibers than urban residents in Korea. Furthermore, Koreans had significantly lower levels of both asbestos and non-asbestos fibers than Japanese.

• Structural Engineering and Mechanics
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• 제76권3호
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• pp.421-433
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• 2020

Masonry infills are normally considered as non-structural elements in design practice, therefore, the interaction between the bounding frame and the strength contribution of masonry infills is commonly ignored in the seismic analysis work of the RC frames. However, a number of typical RC frames with irregular distributed masonry infills have suffered from undesirable weak-story failure in major earthquakes, which indicates that ignoring the influence of masonry infills may cause great seismic collapse risk of RC frames. This paper presented the investigation on the risk of seismic collapse of RC frames with irregularly distributed masonry infills through a large number of nonlinear time history analyses (NTHAs). Based on the results of NTHAs, seismic fragility curves were developed for RC frames with various distribution patterns of masonry infills. It was found that the existence of masonry infills generally reduces the collapse risk of the RC frames under both frequent happened and very strong earthquakes, however, the severe irregular distribution of masonry infills, such as open ground story scenario, results in great risk of forming a weak story failure. The strong-column weak-beam (SCWB) ratio has been widely adopted in major seismic design codes to control the potential of weak story failures, where a SCWB ratio value about 1.2 is generally accepted as the lower limit. In this study, the effect of SCWB ratio on inter-story drift distribution was also parametrically investigated. It showed that improving the SCWB ratio of the RC frames with irregularly distributed masonry infills can reduce inter-story drift concentration index under earthquakes, therefore, prevent weak story failures. To achieve the same drift concentration index limit of the bare RC frame with SCWB ratio of about 1.2, which is specified in ACI318-14, the SCWB ratio of masonry-infilled RC frames should be no less than 1.5. For the open ground story scenario, this value can be as high as 1.8.

• Journal of Acupuncture Research
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• 제22권2호
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• pp.1-12
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• 2005

Objective: With the onset of stroke, white blood cells release several proinflammatory cytokines, including interleukin (IL)-6, IL-10, and tumor necrosis factor $(TNF)-{\alpha}$. It has been proven in previous studies that the release of these cytokines is related to the extent of damage to the brain and to overall prognosis. However, no studies have yet been performed to determine the connection with IL-6 and IL-10. Thus, this study is performed to see whether polymorphisms of IL-6, IL-10, and $TNF-{\alpha}$ genes that show increased serum concentration with the onset of stroke are related to stroke attack in Koreans. Methods : Peripheral blood samples derived from patients with stroke (n=100) and healthy controls (n=100) were taken under informed consent. In subjects with stroke, blood samples were obtained within 24 hours of stroke onset. Genomic DNA was isolated using the Wizard DNA Purification Kit (Promega, Madison, WI). Results : 1. Subjects with Heterozygote (GA) and Homozygote (AA) $TNF-{\alpha}$ gene types showed 2.433 and 20.457 times higher risks of being attacked by stroke, respectively, compared to subjects with wild type (GG) $TNF-{\alpha}$ gene type. The data was still statistically significant after adjusting for age, sex, history of smoking, and history of alcohol drinking. 2. Subjects with Homozygote (CC) IL-6 gene type showed 182.033 times higher risk of being attacked by stroke, compared to subjects with wild type (GG) IL-6 genes. This data was statistically insignificant (p=0.700). The data was still statistically insignificant after adjusting for age, sex, history of smoking, and history of alcohol drinking. 3. Subjects with Heterozygote (GA) and Homozygote (GG) IL-10 gene types showed 8.785 and 3.303 times higher risks of being attacked by stroke, respectively, compared to subjects with wild type (AA) IL-10 genes. The data was still statistically insignificant after adjusting for age, sex, history of smoking, and history of alcohol drinking. Conclusion : Our results suggest that the investigated $TNF-{\alpha}$ and IL-10 gene polymorphisms play an important role in stroke attack, but IL-6 gene polymorphism has not been found to associated with stroke.

• 대한임상독성학회지
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• 제1권1호
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• pp.34-39
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• 2003

Carisoprodol (CSP) is commonly prescribed as a skeletal muscle relaxant. Recently, we encountered 7 suicidal cases in which carisoprodol was detected. We developed a rugged, sensitive, and specific method for the determination of CSP and meprobamate (MPB) by GC and GC/MS. Postmortem blood concentrations of CSP and MPB ranged 22.9-124.4 ,$\mu$g/ml and its metabolite, 26.8-144.5 ,$\mu$g/ml respectively. Among 7 cases studied, Only CSP was ingested in 4 cases and combination of CSP and dextromethorphan was ingested in 2 cases according to the case history and one case was with ethanol. The order of the tissue concentration of CSP and MPB was liver> kidney > brain, and the concentration of MPB was higher than that of CSP in all tissues. The MPB /CSP concentration ratios of urine, bile juice, liver, kidney, brain and blood were 15.7, 4.0, 1.2, 1.4, 1.4 and 1.0 respectively. There was a big difference in concentration of CSP and MPB in 7 cases due to differences in the amount of dose administered and time to death after dosing.