• 한국치위생학회지
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• 제10권2호
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• pp.255-268
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• 2010

Objectives : In the field of dental hygiene, infections pose a serious problem. This issue has left many patients and dental staff exposed to microbes with potentially far-reaching effects. The purpose of this study was to find solutions which could improve Dental health policies and promote improved methods for the control of infections. This survey was conducted between March 3, 2008 and March 30, 2008, in the metropolitan area. The research was carried out in dental clinics and dental hygienists were surveyed through a questionnaire. Methods : Collected data was examined using the SPSS 14.0 program, using frequency, mean and standard deviation analysis, T-test, one-way ANOVA, Scheffe's test and Duncan's test. Further analysis was given using Logistic Regression. Results : The Performance of Infection Control by dental hygienists in Dental Clinics was shown at $2.96{\pm}0.42$. Disinfection, sterilization and the wearing of masks is high at $3.65{\pm}0.64$, $3.64{\pm}0.65$. The perception of the importance of infection control is higher among dental hygienists than dentists. Of the dental hygienists surveyed, 83.9% were exposed to at least one accident while at work. Age and years of experience were important in relation to infection control practices. The rate of infections and the number of accidents experienced related to the dental hygienists performance of infection control. The performance of infection control is influenced by the dental hygienists own perceptions, and the perceptions of their dentists. The dental hygienist's working conditions and their beliefs related to infection control were shown to influence their performance of infection control practices. Conclusion : At the conclusion of this investigation, it was determined that systematic refresher training of infection control should be delivered through further education and various media. Dental health care workers should be encouraged to practice these action items presented in the training. For successful implementation of infection control in every dental health-care setting, it is highly demanded that effective safe-guard tools, strategic support and standardized action items against infection problems are developed.

• 보존과학회지
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• 제33권6호
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• pp.467-483
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• 2017

본 연구에서는 문화재 복원용 속(速)경화형 Epoxy계 수지인 $Araldite^{(R)}$ rapid의 온도 스트레스에 의한 열화 특성을 분석하였다. 인장강도 및 접착강도는 $40{\sim}60^{\circ}C$에서 12,624시간까지 감소하여 내구성 및 접착특성의 미약한 열화가 발생하였다. 외부 응력 및 온도에 대한 안정성은 속(速)경화형에 비해 일반 경화형 Epoxy계 수지가 우수하여, 복원부의 강도 특성 및 응력 상태를 고려한 복원재료의 적절한 선택과 적용이 요구된다. $40{\sim}60^{\circ}C$에서 12,624시간까지 색차의 증가와 광택도의 감소 등 색상 및 광택 안정성은 취약하여, 향후 광학특성의 개선을 위한 안정성 향상 연구가 필요하다. 특히 접착제의 열적 특성(중량감소량, 열분해온도, 유리전이온도)은 기계적 물성 변화에 부분적으로 관여하였고, 피착재의 계면 특성 및 접착제의 기체투과특성(수분투과도)은 접착성능의 중요인자로 작용하였다. 따라서 도자기, 벽돌 및 석재와 같은 다공성 재질의 경우 항온항습에 의한 보존환경 관리가 중요하며, 옥외 전시유물의 경우 노출환경에 의한 물성 변화를 최소화할 수 있는 보존대책의 수립이 절실하다. 향후 이러한 결과는 문화재에 사용된 Epoxy계 수지의 열화속도 및 수명예측 자료로 활용될 것으로 기대된다.

• Reproductive and Developmental Biology
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• 제35권3호
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• pp.221-225
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• 2011

This study was undertaken to evaluate the relationship between in vitro maturation and plasminogen activators (PAs) activity on porcine cumulus-oocytes complexes (COCs) exposed to oxidative stress. When COCs were cultured in maturation medium with hydrogen peroxide ($H_2O_2$), the proportion of the germinal vesicle breakdown (GVBD) and oocytes maturation were decrease with addition of $H_2O_2$, and were significantly (p<0.05) lower in medium with 0.1 mM $H_2O_2$ than control group. Also, the rate of degenerated oocytes was increased in as $H_2O_2$ concentration in eased. When COCs were cultured for 48 h, three plasminogen-dependent lytic bands were observed: tissue-type PA (tPA); urokinase-type PA (uPA); and tPA-PA inhibitor (tPA-PAI). PA activity was quantified using SDS-PAGE and zymography. When $H_2O_2$ concentration was increased, tPA and tPA-PAI activities also increased in porcine oocytes cultured for 48 h, but not uPA. In other experiment, embryos were divided into three groups and cultured in (1) control medium, (2) control medium with 1.0 mM $H_2O_2$ and (3) control medium with 1.0 mM $H_2O_2$ along with catalase in concentrations of 0.01, 0.1, and 1.0 mg/ml, respectively. $H_2O_2$ decreased the rate of GVBD and maturation in porcine COCs but catalase revealed protective activity, against oxidative stress caused by $H_2O_2$. In this experiment, tPA and tPA-PAI activities were higher in media with 1.0 mM $H_2O_2$ alone. Increasing concentration of catalase decreased tPA and tPA-PAI activities in porcine oocytes. These results indicate that the exposure of porcine follicular oocytes to ROS inhibits oocytes maturation to metaphase-II stage and increase the oocytes degeneration. Also, we speculated that increased ROS level may trigger tPA and tPA-PAI activities in porcine oocytes matured in vitro.

• 감성과학
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• 제22권3호
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• pp.103-108
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• 2019

휴전국인 우리나라는 의무복무제도를 시행하고 있다. 이에 취업 및 진학을 한 20대 초반의 사회 초년생은 군입대 문제로 많은 고민과 큰 걱정을 하고 있다. 이에 군에 대한 부정적인 인식과 군 생활 적응은 사회가 같이 풀어야 할 문제이다. 따라서 방송사 등 문제 해결을 위해 다각적으로 노력하고 있으나 역부족이다. 실제 군 입대 후 스트레스 및 불안정 심리상태의 장병 비중이 높다. 따라서 본 연구는 군 생활에서 일상적인 방법을 통해 스트레스, 불안감을 감소시키고, 집중력을 향상 시키고자 실행하였다. 주의 집중력 증가 및 스트레스, 불안감의 변화를 측정하기 위해 SMR파 대역의 주파수를 직접 노출시킨 실험군과 그렇지 않은 대조군으로 실험을 진행하였다. 실험군과 대조군 대한 대응표본 t-검정 결과는 신뢰수준 95%에서 t=2.487, p=0.042로 유의차가 인정되었다. 즉, 가상사격영상에서 특정 주파수를 제시한 실험군의 피실험자들이 스트레스 및 불안정 심리의 완화효과가 발생하였다. 본 실험의 결과를 활용하면 젊은 장병들의 군 생활 적응에 효과가 높은 것으로 사료된다. 추후 연구에서는 심전도와 뇌파의 상관관계의 확인이 필요하다.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.808-817
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• 2011

Because of its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum has a considerable potential in biomass hydrolysis applications. Trichoderma harzianum cellobiohydrolase I (ThCBHI), an exoglucanase, is an important enzyme in the process of cellulose degradation. Here, we report an easy single-step ion-exchange chromatographic method for purification of ThCBHI and its initial biophysical and biochemical characterization. The ThCBHI produced by induction with microcrystalline cellulose under submerged fermentation was purified on DEAE-Sephadex A-50 media and its identity was confirmed by mass spectrometry. The ThCBHI biochemical characterization showed that the protein has a molecular mass of 66 kDa and pI of 5.23. As confirmed by smallangle X-ray scattering (SAXS), both full-length ThCBHI and its catalytic core domain (CCD) obtained by digestion with papain are monomeric in solution. Secondary structure analysis of ThCBHI by circular dichroism revealed ${\alpha}$- helices and ${\beta}$-strands contents in the 28% and 38% range, respectively. The intrinsic fluorescence emission maximum of 337 nm was accounted for as different degrees of exposure of ThCBHI tryptophan residues to water. Moreover, ThCBHI displayed maximum activity at pH 5.0 and temperature of $50^{\circ}C$ with specific activities against Avicel and p-nitrophenyl-${\beta}$-D-cellobioside of 1.25 U/mg and 1.53 U/mg, respectively.

• 한국안광학회지
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• 제12권2호
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• pp.79-86
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• 2007

본 연구는 mycoplasma가 오염된 배양 각막 상피세포에 anti-FAS and anti-FAS ligand antibody를 노출시킨 후 세포고사 메커니즘을 조사하기 위해 시행하였다. 배양각막 상피세포에 anti-FAS antibody 와 anti-FAS ligand antibody를 2일과 4일 동안 처리하여 주어진 기간 동안 배양하였다. 배양 중인 각막상피세포가 mycoplasma sp.에 의해 오염된 것이 밝혀졌다. mycoplasma removal agent(MRA)가 세포주로부터 세균을 제거하기 위해 이용되었다. MRA를 세포주에 첨가하여 1주일 동안 배양하였다. 그 후 각막상피 세포주는 MRA가 포함되지 않는 배양액에서 수세대 동안 배양되어 커버글라스에 계대배양하여 50-80% 채워졌을 때 MRA 제거여부를 확인하기 위한 검사 키트에 제공된 Hoechst staining을 이용하여 염색하였다. 세포고사 실험은 MRA 제거 전과 제거 후에 시행되었다. mycoplasma가 오염된 배양 각막상피세포에 대한 anti-FAS and anti-FAS ligand antibody의 영향을 알아보기 위해 Hoechst 33342 staining과 Annexin V-FITC and Propidium Iodide Staining을 이용하여 세포고사 유도를 확인하였다. 본 연구는 anti-FAS antibody가 배양각막 상피세포에서 시간과 농도에 비례하는 메커니즘으로 세포고사를 유도한다. mycoplasma가 오염된 세포주는 FAS 유도 세포고사의 민감성을 증가시키는 것으로 나타났다.

• 한국습지학회지
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• 제9권1호
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• pp.79-89
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• 2007

This paper provides a comprehensive overview of the present status of several environmental problems caused by emerging toxic substances such as persistent organic pollutants (POPs), endocrine disrupting chemicals (EDCs), and arsenic in various environmental media in Vietnam. Monitoring data reported during the 1990s demonstrated elevated contamination of DDTs in most of these compartments in Vietnam. Studies in frame of the Asia-Pacific Mussel Watch Program revealed that fish, mussels and resident birds from Vietnam contained higher concentrations of DDTs as compared to other countries in region, suggesting the role of Vietnamese environment as a significant emission source of DDT in the Southeast Asian region. The estimated dietary intakes of PCBs and DDTs for Vietnamese were relatively high among Asian developing countries, suggesting potential risk for humans posed by thesechemicals. Widespread contamination of some endocrine active compounds such as alkylphenols and phthalates was observed at various sites along the coasts of northern and middle Vietnam. The presence of significant source of bisphenol-A along Red River estuary was revealed with the concentrations comparable to those reported for developed nations. A case study on seasonal variation of alkylphenols and phthalates in surface water of river delta and estuary of north and middle Vietnam indicated the differences in distribution of these compounds between dry and rainy seasons. Higher concentrations of alkylphenols and phthalates were found in dry season in estuary; while the contrasting pattern was observed in the river delta, showing elevated residues in rainy season. This result suggests the different behavior of alkylphenols and phthalates in river delta and coastal environment. From ecotoxicological perspectives, concentrations of bis-phenol A and di(2-ethylhexyl)phthalates [DEHP] in surface water from some locations in Vietnam exceeded the guideline values for Ecotoxicological Effects and the Environmental Risk Limit, respectively, suggesting potential for toxic implications on aquatic wildlife. Widespread and elevated arsenic contamination was discovered inour recent surveys in groundwater in a large area of suburban areas of Hanoi city, the capital of Vietnam. The most recent investigation in 4 villages showed about more than 50 % of groundwater samples contained As concentrations exceeding 50 g/L (the WHO and Vietnamese standard). In particular, in Son Dong villages, 58 % of samples analyzed contained As concentrations higher than 200 g/L. Good correlations were found in As concentrations in water and hair and urine of peoples in corresponding families, suggesting the chronic exposure to As by people living in As-contaminated ground water areas. In Son Dong village, As levels in hair (mean: 1.7 mg/kg dry wt) and urine (g/g creatinine) exceeding the reference values recommended by WHO, suggesting potential for human risk posed by long term accumulation of As in human body. Future studies should be focused on the time trends of POPs and EDCs in biota in Vietnam in order to predict future trend of contamination and to reveal new clues for understanding possible toxic impacts on aquatic organisms. The issues of arsenic contamination in groundwater and their chronic toxic implications on human health should be systematically investigated in the future.

• 한국ITS학회 논문지
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• 제17권5호
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• pp.143-150
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• 2018

RF 기반 고속 무선통신 기술이 급속히 발전함에 따라 무선 주파수 대역을 기반으로한 IoT 네트워크용 디바이스가 빠르게 보급되고 있으나, 최근 IoT 네트워크 디바이스의 급속한 확산 속도에 비하여 RF 통신 기술의 발전속도가 미치지 못하고 있다. 이러한 상황에서 가시광원을 송신수단으로 사용하는 OWC 기술은 RF 기반 무선 통신의 대역 고갈 문제를 극복 할 수 있는 기술로서 주목받고 있으나, OWC용 데이터 수신 중 발생하는 LED 조명 형태의 왜곡으로 인하여 LED 조명 검출율이 저하되고 RoI의 설정이 부정확해지는 현상이 발생 할 가능성이 있다. 본 논문에서는 Adaptive Median Filter를 적용한 저속 카메라 통신용 LED 조명 검출 알고리즘을 제안하였다. 이를 통해 명확한 RoI 설정 및 LED 조명 검출이 가능할 것으로 사료되며, 본 연구결과를 통해 RF 기반 무선 통신기술의 보완재로서의 역할을 효율적으로 수행 할 수 있을 것으로 판단된다.

• 한국산림과학회지
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• 제99권1호
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• pp.125-130
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• 2010

식물대량증식에서 생물반응기의 이용은 규모를 대량화하고 자동화 할수 있다는 점에서 생산비를 절감할 수 있는 방법 중 하나이다. 본 연구에서는 유칼리 펠리타 선발목의 대량증식 체계를 확립하기 위해 4가지의 생물반응기 배양시스템에서 유칼리의 생장을 비교하였다. 배양기내에 지지물(net)을 설치하고 매 4시간마다 30분씩 액체배지를 공급한 TIN 배양(Temporary immersion with net)에서 식물체 생장이 가장 좋았다. TIN 시스템하에서 자란 식물체는 동일한 방식에 net가 없는 TIX 배양(Temporary immersion without net)에서 자란 식물체와 비교하여 초장이 3배 이상 증가하였다. 게다가 TIN 시스템에서 생산 된 식물체는 총 엽록소 함량, 엽록소 a/b, 그리고 건물중 등도 증가하였다. 위와 같은 결과는 기내 유칼리나무 생장에 중요한 요인이 식물체가 적당한 간격으로, 그리고 적당한 시간동안 배지에 노출되어야하고, net의 이용이 필수적임을 보여준다. TIN 시스템은 유칼리 클론묘의 대량생산을 위해 최적의 시스템으로 산업화를 위한 유칼리나무 대량생산시 유용하게 이용될 수 있을 것으로 생각된다.

• Tuberculosis and Respiratory Diseases
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• 제74권4호
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• pp.163-168
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• 2013

Background: In uncontrolled hemoptysis patient, bronchial arteriography and bronchial artery embolization (BAE) is a important procedure in diagnosis and treatment. The aim of this study is to assess the incidence of contrast-induced nephropathy and the risk factors of contrast-induced nephropathy (CIN) after bronchial arteriography and BAE. Methods: We retrospectively reviewed the medical records of the patients who underwent bronchial arteriography and BAE in two university hospitals from January 2003 to December 2011. CIN was defined as rise of serum creatinine more than 25% of baseline value or 0.5 mg/dL at between 48 hours and 96 hours after bronchial arteriography and BAE. We excluded patients who already had severe renal insufficiency (serum creatinine${\geq}4.0$) or had been receiving dialysis. Results: Of the total 100 screened patients, 88 patients met the enrollment criteria. CIN developed in 7 patients (8.0%). The mean duration between the exposure and development of CIN was $2.35{\pm}0.81$ days. By using multivariate analysis, serum albumin level was found to be significantly associated with the development of CIN (p=0.0219). Conclusion: These findings suggest that the incidence of CIN was higher than expected and patients with hypoalbuminemia should be monitored more carefully to prevent the development of CIN after bronchial arteriography and BAE.