• Toxicological Research
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• 제35권4호
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• pp.343-351
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• 2019

Many in vitro developmental toxicity assays have been proposed over several decades. Since the late 1980s, we have made intermittent attempts to introduce in vitro assays as screening tests for developmental toxicity of inhouse candidate products. Two cell-based assays which were developed two decades apart were intensively studied. One was an assay of inhibitory effects on mouse ascites tumor cell attachment to a concanavalin A-coated plastic sheet surface (MOT assay), which we studied in the early days of assay development. The other was an assay of inhibitory effects on the differentiation of mouse embryonic stem cell to beating heart cells (EST assay), which we assessed more recently. We evaluated the suitability of the assays for screening in-house candidates. The concordance rates with in vivo developmental toxicity were at the 60% level. The EST assay classified chemicals that inhibited cell proliferation as embryo-toxic. Both assays had a significant false positive rate. The assays were generally considered unsuitable for screening the developmental toxicity of our candidate compounds. Recent test systems adopt advanced technologies. Despite such evolution of materials and methods, the concordance rates of the EST and MOT systems were similar. This may suggest that the fundamental predictivity of in vitro developmental toxicity assays has remained basically unchanged for decades. To improve their predictivity, in vitro developmental toxicity assays should be strictly based on elucidated pathogenetic mechanisms of developmental toxicity.

• Communications for Statistical Applications and Methods
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• 제27권6호
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• pp.701-714
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• 2020

Quantitative high throughput screening (qHTS) assays are used to assess toxicity for many chemicals in a short period by collectively analyzing them at several concentrations. Data are routinely analyzed using nonlinear regression models; however, we propose a new method to analyze qHTS data using a nonlinear mixed effects model. qHTS data are generated by repeating the same experiment several times for each chemical; therefor, they can be viewed as if they are repeated measures data and hence analyzed using a nonlinear mixed effects model which accounts for both intra- and inter-individual variabilities. Furthermore, we apply a one-step approach incorporating robust estimation methods to estimate fixed effect parameters and the variance-covariance structure since outliers or influential observations are not uncommon in qHTS data. The toxicity of chemicals from a qHTS assay is classified based on the significance of a parameter related to the efficacy of the chemicals using the proposed method. We evaluate the performance of the proposed method in terms of power and false discovery rate using simulation studies comparing with one existing method. The proposed method is illustrated using a dataset obtained from the National Toxicology Program.

• 한국의류산업학회지
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• 제10권5호
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• pp.676-682
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• 2008

In this study a guideline of the 3D-fit pattern for the ECG(electrocardiogram) measurement of elderly's u-healthcare clothes was proposed. In the screening test of the ECG measurement band, ECG peak band was observable at the band pressure of 0.20 kPa. By employing a 3D body image, tight-fit 3D patterns were made at two different reduction rates of 21%(pattern 1) and 33%(pattern 2), and corresponding pressure of both of the clothes were 0.25 kPa and 0.54 kPa, respectively. Typical waves of ECG were found in both stationary and moving position. In terms of the subjective evaluation of the u-healthcare clothes when worn, it was confirmed that reduction pattern 1(0.25 kPa) conveyed comfortable clothing pressure and pleasantness, which is very close to the result of screening test of ECG band experiment. As results, it is recommended that reduction rate should be adjusted, so that clothing pressure is about 0.2 kPa for the elderly's comfortable and efficient u-healthcare clothes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.342-348
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for plaster boards or cements from waste Plaster board. We could disintegrate preferentially gypsum to gypsum needle in 10${\mu}{\textrm}{m}$ or less size among the contents of waste plaster board (gypsum, paper, fiber, and inorganic material .etc.) by hydration afterwards the dehydration of crushed waste plaster board. In this case, the optimum conditions for minimizing the size of gypsum were dehydration rate of 75%~ 85%, hydration concentration of 10~20%, agitation speed of 250~400rpm, crushing size of 2cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield from under screenings of 325mesh wet screening which followed by the dehydration-hydration process performed in the conditions of dehydration rate of 80%, hydration concentration of 15%, agitation speed of 300rpm, crushing size of 2cm or less. Subsequently, Plate-like Crystalline gypsum of is 151${\mu}{\textrm}{m}$ size and the grade of 99.49% with the Yield of 98.0% from the upper screenings of 270mesh wet screening carried out after the re-crystallization of the recovered gypsum needle slurry.

• 자원리싸이클링
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• 제10권6호
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• pp.43-52
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for Plaster boards or cements from waste Plaster board. Gypsum could be Preferentially disintegrated to gypsum needle in $10\mu\textrm{m}$ or less size by hydration after the dehydration of crushed waste Plaster board. The finer the gypsum needle, it is easier to remove coarse impurities and to recover the gypsum needle. The optimum conditions for obtain the finer gypsum size were dehydration rate of 75~85%, solid concentration at hydration of 10~15%, agitation speed of 250~400 rpm, crushing size before dehydration of 2 cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield as the undersize of 325 mesh wet screening followed by the dehydration-hydration process performed at the conditions of dehydration rate of 80%, solid concentration at hydration of 15%, agitation speed of 300 rpm, crushing size before dehydration of 2 cm or less. After the recrystallization of recovered gypsum, Plate-like gypsum of $151\mu\textrm{m}$ size with 99.49% grade was obtained as the oversize of 270 mesh in a wet screening.

• 대한치과의사협회지
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• 제49권3호
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• pp.136-145
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• 2011

Oral cavity cancer accounts for approximately 3-4% of all malignancies and is a significant worldwide health problem. The Korea Central Cancer Registry estimates that there will be approximately 1500 new cases of oral cancer in Korea. Oral cancer occurs most commonly in middle-aged and elderly individuals. The majority of oral malignancies occur as squamous cell carcinomas and despite remarkable advances in treatment modalities, the 5-year survival rate has not significantly improved over the past several decades, hovering at about 50% to 60%. The unfavorable 5-year survival rate may be attributable to several factors. First, oral cancer is often diagnosed at a late stage, with late stage 5-year survival rates as low as 22%. Additionally, the development of secondary primary tumors in patients with early stage disease has a major impact on survival. The early detection of oral cancer and premalignant lesions offers the promise to cure chance of oral cancer. The major diagnostics moddalities for oral cancer include oral cavity examination, supravital staining, oral cytology, and optical detection systems. But the clinical finding of oral mucosa is the most important key to confirm the oral cancer until now. The traditional clinical examination of oral cavity can be performed quickly, is without additional diagnostic expense to patients, and may be performed by health care professionals. Therefore, clinicians must be well-acquainted with clinical characteristics of oral cancer and practice routine screening for oral cancer in dental clinic to decrease the morbidity and mortality of disease.

• Environmental Engineering Research
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• 제24권2호
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• pp.298-308
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• 2019

This work deals with the membrane fouling mode and the unclogging in seawater ultrafiltration process. The identification of the fouling mechanism by modeling the experimental flux decline was performed using both the classical models of Hermia and the combined models of Bolton. The results show that Bolton models did not bring more precise information than the Hermia's and the flux decline can be described by one of the four Hermia's models since the backwash interval is ${\leq}60$ min. An experimental screening study has been then conducted to choose among 5 parameters (backwash interval, duration, pulses and the flow-rate or injected hypochlorite concentration) those that are the most influential on the fouling and the net water production. It has emerged that fouling is mainly affected by the backwash interval; its prolongation from 30 to 60 min engenders an increase in the reversible fouling and a decrease in the irreversible fouling. This later is also significantly reduced when the hypochlorite concentration increases from 4.5 to 10 ppm. Moreover, the net water production significantly increases with increasing the filtration duration up to 60 min and decreases with decreasing the backwash duration and backwash flow-rate from 10 to 40 s and from 15 to ${\geq}20L.min^{-1}$, respectively.

• 대한통합의학회지
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• 제8권4호
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• pp.59-66
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• 2020

Purpose : This study aimed to present normative data for older Korean adults completing the Yonsei dual task cognitive screening test (Y-DuCog) and identify changes in cognitive function on the Montreal Cognitive Assessment - Korean (MoCA-K) with age. Methods : From May 2019 to August 2019, 195 healthy adults aged ≥60 years participated in this study. All participants completed the Y-DuCog to assess their dual-task performance and the MoCA-K to assess their cognitive function. Participants were divided into three groups based on their age: 60~69 years, 70~79 years, and ≥80 years. Results : The results of the Y-DuCog showed that dual-task performance time, effect, and correct response rate decreased significantly with age (p<.001). Scores from the three groups showed differences on all items (p<.001). Cognitive function on the MoCA-K also decreased significantly with age (mean score ± standard deviation [SD]; 27.33 ± 2.61 in subjects aged 60~69 years; 24.82 ± 3.20 in subjects aged 70~79 years; and 22.10 ± 4.91 in subjects aged ≥80 years; p<.001). Conclusions : Occupational therapists should be aware of the decline in cognitive function and dual-task performance time, effect, and correct response rate in older adults and consider interventions to treat this decline. Further studies are needed with larger groups of participants to examine factors, such as sex and education, that may impact dual-task performance and cognitive function.

• 농촌의학ㆍ지역보건
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• 제38권3호
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• pp.174-181
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• 2013

이 연구에서는 위암검진 참여 현황을 파악하고, 수검률에 영향을 미치는 요인 중 사회경제상태 지표인 소득, 교육수준과 위암 수검률의 관련성을 알아보고자 하였다. 이 연구는 2009년과 2010년 전라남도 지역사회 건강조사 자료를 이용하였으며 40세부터 69세까지 21,220명을 대상으로 분석하였다. 사회경제상태와 위암 수검률과의 관련성은 로지스틱 회귀분석을 이용하여 분석하였다. 연령별 암 수검률은 40대 52.1%, 50대 63.7%, 60대 67.3%로 연령에 따라 증가하였다. 교육 수준이 높을수록 위암 수검률에 대한 교차비는 증가하였다(무학을 포함한 초등학교 졸업을 기준으로 중학교 졸업 OR=1.21; 95% CI=1.07-1.37, 고등학교 졸업 이상 OR=1.41; 95% CI=1.26-1.58). 또한 소득이 높을수록 위암 수검률에 대한 교차비도 증가하였다(2사분위 OR=1.14; 95% CI=1.02-1.28, 3사분위 OR=1.30; 95% CI=1.13-1.48, 4사분위 OR=1.62; 95% CI=1.44-1.84). 소득수준에 따른 위암 검진율은 연령대에 따라 다른 양상을 보였다. 이러한 차이는 40대에서 가장 높았다(40대 2사분위 OR=1.26; 95% CI=1.03-1.54, 3사분위 OR=1.49; 95% CI=1.20-1.86, 4사분위 OR=2.03; 95% CI=1.65-2.50, p for interaction=0.05). 낮은 사회경제상태는 낮은 위암 수검률과 관련이 있었으며, 특히 40대에서 사회경제상태에 따른 위암 수검률 차이가 크게 나타났다. 사회경제상태에 따른 위암 수검률 격차를 줄이기 위해서는 연령대별로 검진 형평성 달성을 위한 정책적, 환경적 지원이 요구될 것으로 보인다.

• 대한유전성대사질환학회지
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• 제16권1호
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• pp.18-23
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• 2016

TMS가 확산되고 검사가 많아짐에 따라 위양성 건수도 증가하고 있다. 본 연구에서는 2012년 1월 1일부터 2014년 12월 31일까지 단일 기관에서 출생한 신생아를 대상으로 시행한 TMS의 위양성율을 조사하고 관련된 요인들을 분석하였다. 총 검사 대상자 중 남아는 8,942명(51.7%), 여아는 8,350명(48.3%)이었고, 평균 제태연령은 $38.6{\pm}1.7$주 였다. 평균 출생 체중은 $3,155.6{\pm}502.4g$, 평균 출생 신장은 $49.1{\pm}2.9cm$, 평균 체질량지수는 $13.0{\pm}3.8kg/m^2$ 이었다. 질식 분만은 9,713 (56.2%)건, 제왕절개는 7,579 (43.8%)건이었다. 평균 검사 시행일은 $2.8{\pm}1.1$일이었다. 위양성을 포함하여 TMS에서 양성으로 확인된 224명은 전체 대상자의 1.3%였다. 다중 로지스틱 회귀분석을 통해 분석한 결과 27주 이하의 초미숙아에서 위양성으로 나타날 odds ratio가 6.957 (95% CI: 1.273-38.008), 1,000 g 이하의 극저체중아에서 5.616 (95% CI: 1.134-27.820)로 나타났다. 위양성 대상자들 중에서는 지방산 대사이상 질환(fatty acid oxidation dis-orders)이 104명(47%), 아미노산 이상질환(amino-acidopathy)가 75명(34%), 유기산 이상 질환(organic aciduria)가 43명(19%)이었다. 전국적인 자료를 모아 평가한다면 국내 발생률에 대한 정확한 평가 및 접근이 가능할 것으로 생각한다.