유기용제노출이 직업적 청력손실에 미치는 영향

이지호,고영주,이헌,강정학,유철인,이충렬,김양호 大韓産業醫學會 2000 대한직업환경의학회지 Vol.12 No.4

목적 : 산업 장에서 노출되는 유기용제가 청력역치에 어떠한 영향을 미치는가를 5년 동안의 추적조사를 통하여 파악하고자 하였다. 방 법 : 유기용제와 소음에 동시에 노출된 근로자 43명과 소음노출수준, 연령, 근무경력을 짝짓기 한소음노출군을 대상으로 문진과 이경검사, 소음노출 수준, 유기용제노출수준을 조사하였다. 결과 : 1. 전체 근로자의 각 주파수별 청력역치 변화양상에서 500Hz∼2000Hz에서는 추적기간 동 소음동안 현저한 변화가 없었고, 4000Hz 및 8000Hz에서는 역치가 증가하는 경향을 나타내었다. 2.유기용제와 소음에 동시에 노출된군에서 소음 노출군에 비해 4000Hz 이상에서 청력역치가 높게 나타났으나, 통계적인 유의성은 없었다(p(0.05). 3.반복측정 분산분석 법으로 각 주파수별 평균청력 역치의 연차적 변화에 미치는 영향을 분석한 결과 유기용제 노출은 통계적으로 유의한 영향이 없었으나(p)0.05), 소음노출수준은 250Hz, 2000Hz 및 4000Hz에서, 연령은 250Hz와 500Hz에서 통계학적으로 유의한 영향을 미치는 것으로 나타났다(p(0.05). 4.소음노출군파 동시노출군 각각에서의 청력역치 변화량을 paired t-test로 비교한 결과 250Hz∼4000Hz에서는 통계학적 유의성이 없었으며(p(0.1), 8000Hz에서만 경계치 (p=0.0884)의 유의성을 나타내었다. 5.요인들의 영향을 보정한 상태에서 관찰하기 위해 관찰기간동안의 청력역치변화량을 종속변수로 두고 일반선형모형을 이용하여 주파수별로 관찰한 결과 8000Hz에서만 모델에 통계학적 유의성이 있었으며 (p(0.05), 여기서 소음노출수준이 통계학적으로 유의한 영향을 미치는 것으로 나타났고(p(0.05), 유기용제노출은 경 계수준이 었다(p=0.087). 결론 : 청력에 대한 유기용제의 영향이 소음과 연령에 비해 상대적으로 미미하여 명확한 결론에 이르지는 못하였으나, 다소 영향이 있는 것으로 생각되어 유기용제의 영향에 대한 추가연구가 필요할 것으로 판단된다. 또한 보다 효과적인 근로자들의 청력관리를 위해서는 소음 외 산업 장에서 동시에 노출되는 여러 유해물질들을 고려하여야 할 것이다. Objectives : This study was to evaluate the impacts of simultaneous exposure to noise and mixed solvents on workers'hearing threshold level (HTL) over five-year period. Methods : The study was conducted by interview and annual audiometric test on workers in ship building industry from 1994 to 1998. The cases(workers who exposed to noise and mixed solvent simultaneously) were 43 male workers and controls (workers who exposed to nolle) were selected by matching method with regard to age, sex, carrier, and noise exposure level. To assess the impacts of solvent exposure on hearing threshold level, with considering other factors, general liner model was used. Results : 1. The audiogram of all subjects showed typical sensorineural hearing loss pattern. The mean HTLe were increased at high frequency (4000HB and 8000Hz) for study period. 2. The HTLs of cases were more increased than those of controls at high frequencies (4000Hz and 8000Hz), but there was not statlstical significance. 3. The impact of age on the HTL was statistically significant at 250Hz and 500Hz (p(0.05), and the impact of noise on the HTL was statistically significant at 250Hz, 2000Hz and 4000Hz (p(0.05), but the impact solvent exposure on the HTL was not significant. 4. The changes in HTLs of cases were higher than those of controls at high frequency, there were not statistical significance at 4000Hz, but only at 8000Hz (p=0.087). 5. Statistical analysis of the general linear model implicated that the changes in HTL was impacted by noise exposure bevel significantly (p=0.031) and Impacted by solvent exposure weakly (p=0.087) at 8000Hz. Conclusions : The results of this study suggest that workers who simultaneously exposed to noise and mixed solvent were at risk for more affected HTL than those exposed to noise exposure only, but we could not find definitive evidence. Further detailed studies must be made in large number of workers.

기성 콘크리트 파일 두부정리를 위한 자동화 장비의 개발

이정호,김정렬,김영석,조문영,김성근 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

During the last few years, the use of prefabricated concrete pile has been gradually increased in many construction sites. Cutting work of the concrete pile is an important task to crush a part of pile head which is compressed with more than 800㎏/㎠, It is usually performed by a crusher and three to four skilled workers. Recent analysis results of the pile cutting work reveal that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is labor-intensive work. The primary objective of this study is to propose conceptual designs for developing an automated pile cutting machine. It is anticipated that the development of the automated pile cutting machine would be able to bring improvements in safety, productivity, quality as well as cost saving.

생체모사환경에서 DLC 필름의 부식마모 특성에 미치는 Si 함량의 영향에 관한 연구

김호건,김우중,김정구,박세준,이광렬 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.3

In a method to improve resistance to wear, corrosion and mechanical properties of protective coating, DLC coatings have been extensively studied over the past several years due to their unique combination of properties. Especially, Si-DLC coatings have been attracting increasing interest of researchers since they have a great potential for solving some of the major disadvantages of pure DLC coatings. Si-incorporated diamond-like carbon (Si-DLC) coatings ranging from 0 to 2 at.% were deposited on Ti alloy substrate by means of r.f. plasma-assisted chemical vapor deposition (r.f. PACVD) technique, using mixtures of benzene (C_(6)H_(6)) and silane (SiH_(4)) as the reaction gases. Corrosion and wear behavior of DLC coatings was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy), tribological techchnique(wear test) and surface analyses (atomic force microscopy, scanning electron microscopy and Raman spectroscopy). It was found that DLC coatings with increasing Si content could acquire improved corrosion and wear resistance in the simulated body fluid environment (0.89 wt.% NaCl of pH 7.4 at 37℃). (Received December 6, 2004)

인공고관절용 스테인리스강 316L에 증착된 다이아몬드상 카본 필름의 전기화학적 특성에 관한 연구

김호건,안승호,김정구,박세준,이광렬 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.4

Diamond-like carbon (DLC) films have several advantages in applications such as high hardness, chemical inertness, low friction and electrical insulation. Furthermore, DLC-coated STS 316L films have been reported to have a good biocompatibility, such as the absence of inflammatory response. Thus, corrosion resistance is the first consideration for the biomaterials to be used in the body. DLC films have been deposited onto substrates of STB 316L for artificial hip joints using r.f PACVD (plasma-assisted chemical vapor deposition) with C_(6)H_(6) and mixture of C_(6)H_(6) and SiH_(4) as the process gases. Three kinds of DLC-coated films were prepared as a function of diverse bias voltage and Si incorporation. Corrosion behavior of DLC films was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy) and surface analyses (atomic force microscopy and scanning electron microscopy). The electrolyte used in his test was a 0.89%NaCl solution of pH 7.4 at temperature 37℃. Electrochemical measurements showed that DLC films with higher bias voltage and Si incorporation could improve corrosion resistance in the simulated body fluid environment. (Received December 5, 2003)

Comparison of dietary intake patterns in hemodialysis patients by nutritional status: A cross-sectional analysis

( Ji Eun Lee ),( Hyun-jung Kim ),( Mi Jung Lee ),( Young Eun Kwon ),( Min-sook Kyung ),( Jung-tak Park ),( Jung Pyo Lee ),( Su-hyun Kim ),( Jung-hyun Kim ),( Hyung Jung Oh ),( Dong-ryeol Ryu ) 대한신장학회 2020 Kidney Research and Clinical Practice Vol.39 No.2

Background: Although appropriate dietary adjustments in hemodialysis (HD) patients are important, most HD patients have difficulty adhering to dietary therapy due to the stress of a restricted-food diet or loss of appetite, which eventually leads to malnutrition and other complications. The dietary intake of HD patients stratified by nutritional status has not yet been studied. Methods: In total, 111 HD patients from five dialysis centers were stratified into 2 groups based on the Subjective Global Assessment: the well-nourished group and the poorly nourished group. The 7-day dietary intake and food behaviors of the two groups were compared. Logistic regression analysis was performed to reveal the factors associated with poorly nourished status. Results: The 7-day dietary survey showed a lower intake of total calories and protein and a higher intake of sodium and potassium than in the standard recommendations, but there were no differences between groups. The poorly nourished group ate fried food significantly more frequently than the well-nourished group. Moreover, higher hip and waist circumferences were significantly associated with poorly nourished status. Conclusion: We found differences in the dietary intake patterns and food behaviors between well- and poorly nourished HD patients. Further research is needed to design customized nutritional education, consultations, and dietary management for HD patients.

Forming Gas Post Metallization Annealing of Recessed AlGaN/GaN-on-Si MOSHFET

Jung-Yeon Lee,Bong-Ryeol Park,Jae-Gil Lee,Jongtae Lim,Ho-Young Cha 대한전자공학회 2015 Journal of semiconductor technology and science Vol.15 No.1

In this study, the effects of forming gas post metallization annealing (PMA) on recessed AlGaN/GaN-on-Si MOSHFET were investigated. The device employed an ICPCVD SiO₂ film as a gate oxide layer on which a Ni/Au gate was evaporated. The PMA process was carried out at 350℃ in forming gas ambient. It was found that the device instability was improved with significant reduction in interface trap density by forming gas PMA.

Inorganic Arsenite Potentiates Vasoconstriction through Calcium Sensitization in Vascular Smooth Muscle

Lee, Moo-Yeol,Lee, Young-Ho,Lim, Kyung-Min,Chung, Seung-Min,Bae, Ok-Nam,Kim, Heon,Lee, Choong-Ryeol,Park, Jung-Duck,Chung, Jin-Ho National Institute of Environmental Health Science 2005 Environmental health perspectives Vol.113 No.10

<P>Chronic exposure to arsenic is well known as the cause of cardiovascular diseases such as hypertension. To investigate the effect of arsenic on blood vessels, we examined whether arsenic affected the contraction of aortic rings in an isolated organ bath system. Treatment with arsenite, a trivalent inorganic species, increased vasoconstriction induced by phenylephrine or serotonin in a concentration-dependent manner. Among the arsenic species tested—arsenite, pentavalent inorganic species (arsenate), monomethylarsonic acid (MMA<SUP>V</SUP>), and dimethylarsinic acid (DMA<SUP>V</SUP>)—arsenite was the most potent. Similar effects were also observed in aortic rings without endothelium, suggesting that vascular smooth muscle plays a key role in enhancing vasoconstriction induced by arsenite. This hypercontraction by arsenite was well correlated with the extent of myosin light chain (MLC) phosphorylation stimulated by phenylephrine. Direct Ca<SUP>2+</SUP> measurement using fura-2 dye in aortic strips revealed that arsenite enhanced vasoconstriction induced by high K<SUP>+</SUP> without concomitant increase in intracellular Ca<SUP>2+</SUP> elevation, suggesting that, rather than direct Ca<SUP>2+</SUP> elevation, Ca<SUP>2+</SUP> sensitization may be a major contributor to the enhanced vasoconstriction by arsenite. Consistent with these <I>in vitro</I> results, 2-hr pretreatment of 1.0 mg/kg intravenous arsenite augmented phenylephrine-induced blood pressure increase in conscious rats. All these results suggest that arsenite increases agonist-induced vasoconstriction mediated by MLC phosphorylation in smooth muscles and that calcium sensitization is one of the key mechanisms for the hypercontraction induced by arsenite in blood vessels.</P>

Single Port Laparoscopic Surgery: Suture and Tying Techniques

( Jung Ryeol Lee ),( Mi Sun Shin ),( Gwang Yi ),( Byung Chul Jee ),( Chang Suk Suh ),( Seok Hyun Kim ) 대한산부인과학회 2011 대한산부인과학회 학술대회 Vol.97 No.-

Holographic and Light-Field Imaging as Future 3-D Displays

Jung-Young Son,Hyoung Lee,Beom-Ryeol Lee,Kwang-Hoon Lee IEEE 2017 Proceedings of the IEEE Vol.105 No.5

<P>Light-field imaging and holographic imaging are currently the two mostly investigated 3-D imaging technologies because of their potentials to create the viewing environment conforming to a natural viewing condition. The basic optical geometries for image display in these imaging are not different from that of integral photography. The images in the two type of imaging are a set of different view images. These images are arranged as a 2-D point image array, and each point image is expanded with a certain angle to form a viewing zone. The differences between the two types of imaging are the number of point images in the array and the physical entities forming the images. Holographic imaging has many more point images than light-field imaging, and each image in the array consists of coherent right rays from different positions of an object. In light-field imaging, an array of pixels represents a direction view of the object. Despite these differences, they share the same goal of providing a continuous parallax to viewers and require display panels of almost the same characteristics. It is expected that in the future these two imaging techniques will be integrated into the same flat panel along with the plane image.</P>

Fertility preservation in women with ovarian endometriosis

( Jung Ryeol Lee ) 대한산부인과학회 2019 서울심포지움 Vol.24 No.-