• 대한소아치과학회지
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• 제23권4호
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• pp.954-967
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• 1996

Laser application to modify healthy permanent dentin to improve microhardness and caries resistence has been previously reported but the physical modification and ablation thresholds of carious and sclerotic dentin has yet to be identified. This study determined the energy density required by modify (physical modification threshold, PMT) and remove (ablation threshold, AT) infected carious, affected and selerotic dentin compared to healthy permanent dentin. $1{\pm}0.25mm$ thick dentin sections(n=272) from extracted human teeth were used. Smear layer was removed 0.5M EDTA for 2 minutes. Utilizing three pulsed fiberopitc delivered contact lasers with different emission wavelengths($1.06{\mu}m$=Nd : YAG, $2.10{\mu}m$=Ho : YAG and $2.94{\mu}mEr$ : YAG). The energy density($J/cm^2$) was incrementally increased and the resulting tissue interaction classified on a scale from 0-6. A minimum of 5 repetitions/energy density were completed. Light microscopy(10-25X) was used to verify the physical modification(scale=3) and ablation thresholds(scale=4) of the various forms of dentin and the data were analyzed by logistic regression at the 95 % confidence interval. PMT and AT by the laser and the dentin types were: PMT and AT was lower in infected dentin than in sound dentin for all lasers. PMT and AT induced by Nd : YAG>Ho : YAG>Er : YAG for all forms of dentin. Microhardness was increased in sound dentin at PMT. Morphology of crater examined by light microscopy showed Nd : YAG was safe and effective for removing carious dentin and Er: YAG was effective for removing sound dentin. The PMT and AT for YAG lasers are different as a function of dentin type which may be utilized for selective modification and removal of dentin.

• 대한기계학회논문집B
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• 제40권7호
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• pp.429-434
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• 2016

중대형 출력의 해상용 디젤엔진에서 여러 탈질 기술 중 요소(Urea)를 환원제로 사용하는 Urea-SCR 시스템이 가장 검증된 기술로 알려져 있다. 요소수의 경우 Urea-SCR 시스템의 노즐 특성 및 혼합기 유 무에 의한 분무거동 및 혼합특성이 시스템 효율에 지대한 영향을 미친다. 따라서 본 연구는 SCR 시스템의 최적 설계를 위해 혼합기 적용에 따른 반응영역에서의 분무거동 특성 및 암모니아 균일도를 전산해석기법으로 분석하였다. 그 결과 혼합구간의 $NH_3$농도로 비춰 볼 때 SCR 시스템의 성능 향상을 보장하기 위해서는 환원제의 균일도를 고려한 특정 형상의 혼합기의 적용이 필요하다는 것을 알 수 있었다. 특히 선박용 SCR 시스템은 설치 공간 제약에 따라 혼합구간 단축을 위해 혼합기 적용은 필수적임을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1371-1378
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• 2004

A porous stainless steel (SUS) as a substrate of silica composite membranes for hydrogen purification was used to improve mechanical strength of the membranes for industrial application. The SUS support was successfully modified by using submicron Ni powder, $SiO_2$ sols with particle size of 500 nm and 150 nm in turns. Silica top layer was coated on the modified supports under various preparation conditions such as calcination temperature, dipping time and repeating number of dipping-drying process. The calcination temperature for proper sintering was between H ttig temperature and Tamman temperature of the coating materials. Maximum hydrogen selectivity was investigated by changing dipping time. As repeating number of dipping-drying process increased, permeances of nitrogen and hydrogen were decreased and $H_2/N_2$ selectivity was increased due to the reduction of non-selective pinholes and mesopores. For the silica membrane prepared under optimized conditions, permeance of hydrogen was about $3\;{\times}\;10^{-5}\;cm^3{\cdot}cm^{-2}{\cdot}s^{-1}{\cdot}cmHg^{-1}$ combined with $H_2/N_2$ seletivity of about 20.

• Tuberculosis and Respiratory Diseases
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• 제69권2호
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• pp.75-80
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• 2010

The year of 2009~2010 brought a number of concepts and new ideas were evaluated with promising results. However, some studies that challenged many beliefs. In acute respiratory distress syndrome (ARDS), recent clinical studies took into consideration of pathophysiologic changes of respiratory system compliance. Meta-analysis of positive end-expiratory pressure trials showed survival benefit of high positive end-expiratory pressure in ARDS. Until now, prone positioning did not show survival benefit in patients with ARDS. Extracorporeal membrane oxygenation (ECMO) based management improved survival in patients with severe ARDS. ECMO can be a management option in severe ARDS. Sedation is a standard practice in critically ill patients needing mechanical ventilation. However, Danish group reported less sedation of critically ill patients receiving mechanical ventilation was associated with an increase in days without ventilation. Although this single center study has some limitations, the overall results are promising. Use of maximal sterile barrier precautions (mask, sterile gown, sterile gloves, and large sterile drapes) with chlorhexidine-impregnated dressing reduced central venous catheter related infection. Selective oropharyngeal decontamination (application of topical antibiotics in the oropharynx) reduced the mortality rate of an intensive care unit (ICU) population. Normoglycemia in Intensive Care Evaluation and Survival Using Glucose Algorithm Regulation (NICE-SUGAR) trial reported intensive glucose control increased mortality among adults in the ICU. Some of the results of above papers are promising. However, some ideas may need for more frequent individual assessment and increase the workload of ICU staffs. Before implementation of new practice in ICU, we should take into consideration of individual hospital situation including human and material resources.

• 한국식품영양과학회지
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• 제31권3호
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• pp.469-474
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• 2002

본 연구는 반건조 오징어의 저장기간 연장을 위해 감마선 조사기술의 적용 가능성을 평가하기 위해 수행되었다. 반건조 오징어를 함기 및 진공포장하여 0, 3, 5, 7 kGy로 조사한 후에 1$0^{\circ}C$에서 저장하면서 실험에 사용하였다. 미생물학적 측면에서 비조사구는 저장기간 동안 급속하게 부패가 진행되었으며, 선택배지를 사용한 검사에서 곰팡이와 효모가 저장 중 반건조 오징어의 주요 오염미생물로 확인되었다. 감마선 조사로 미생물수가 감소하였으며, 반건조 오징어의 보존을 위해서는 7 kGy 이상의 선량이 요구되었다. VBN 함량은 저장 중 조사선량이 증가할수록 함량의 증가가 억제되는 것으로 나타났다. 조사 직후 TBA값은 모든 처리구에서 차이가 없었다. 감마선 조사에 의한 관능적인 차이는 관찰되지않았다.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.31.1-31.20
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• 2020

Matrix metalloproteinases (MMPs) are enzymes that can degrade collagen in hybrid layer and reduce the longevity of adhesive restorations. As scientific understanding of the MMPs has advanced, useful strategies focusing on preventing these enzymes' actions by MMP inhibitors have quickly developed in many medical fields. However, in restorative dentistry, it is still not well established. This paper is an overview of the strategies to inhibit MMPs that can achieve a long-lasting material-tooth adhesion. Literature search was performed comprehensively using the electronic databases: PubMed, ScienceDirect and Scopus including articles from May 2007 to December 2019 and the main search terms were "matrix metalloproteinases", "collagen", and "dentin" and "hybrid layer". MMPs typical structure consists of several distinct domains. MMP inhibitors can be divided into 2 main groups: synthetic (synthetic-peptides, non-peptide molecules and compounds, tetracyclines, metallic ions, and others) and natural bioactive inhibitors mainly flavonoids. Selective inhibitors of MMPs promise to be the future for specific targeting of preventing dentin proteolysis. The knowledge about MMPs functionality should be considered to synthesize drugs capable to efficiently and selectively block MMPs chemical routes targeting their inactivation in order to overcome the current limitations of the therapeutic use of MMPs inhibitors, i.e., easy clinical application and long-lasting effect.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.653-667
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• 2017

The significant advances in information and communication technologies are changing the process of how information is accessed. The internet is a very important source of information and it influences the development of other media. Furthermore, the growth of digital content is a big problem for academic digital libraries, so that similar tools can be applied in this scope to provide users with access to the information. Given the importance of this, we have reviewed and analyzed several proposals that improve the processes of disseminating information in these university digital libraries and that promote access to information of interest. These proposals manage to adapt a user's access to information according to his or her needs and preferences. As seen in the literature one of the techniques with the best results, is the application of recommender systems. These are tools whose objective is to evaluate and filter the vast amount of digital information that is accessible online in order to help users in their processes of accessing information. In particular, we are focused on the analysis of the fuzzy linguistic recommender systems (i.e., recommender systems that use fuzzy linguistic modeling tools to manage the user's preferences and the uncertainty of the system in a qualitative way). Thus, in this work, we analyzed some proposals based on fuzzy linguistic recommender systems to help researchers, students, and teachers access resources of interest and thus, improve and complement the services provided by academic digital libraries.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.281.2-281.2
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• 2013

Since heavy metal ions included in water or food resources have critical effects on human health, highly sensitive, rapid and selective analysis for heavy metal detection has been extensively explored by means of electrochemical, optical and colorimetric methods. For example, quantum dots (QDs), such as semiconductor QDs, have received enormous attention due to extraordinary optical properties including high fluorescence intensity and its narrow emission peaks, and have been utilized for heavy metal ion detection. However, the semiconductor QDs have a drawback of serious toxicity derived from cadmium, lead and other lethal elements, thereby limiting its application in the environmental screening system. On the other hand, Graphene oxide (GO) has proven its superlative properties of biocompatibility, unique photoluminescence (PL), good quenching efficiency and facile surface modification. Recently, the size of GO was controlled to a few nanometers, enhancing its optical properties to be applied for biological or chemical sensors. Interestingly, the presence of various oxygenous functional groups of GO contributes to opening the band gap of graphene, resulting in a unique PL emission pattern, and the control of the sp2 domain in the sp3 matrix of GO can tune the PL intensity as well as the PL emission wavelength. Herein, we reported a photoluminescent GO array on which heavy metal ion-specific DNA aptamers were immobilized, and sensitive and multiplex heavy metal ion detection was performed utilizing fluorescence resonance energy transfer (FRET) between the photoluminescent monolayered GO and the captured metal ion.

• Journal of Plant Biotechnology
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• 제37권4호
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• pp.408-413
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• 2010

국내 과수분야의 형질전환 연구동향과 전망에 대해 살펴보았다. 과수에서 형질전환 기술은 교배육종의 한계를 극복하고 보완할 수 있는 기술의 하나로 여겨지고 있고 1990년 초반 이래 기술개발에 대한 연구가 수행되어 오고 있다. 사과에서는 후지, 감홍 등의 주요 재배품종에 대한 형질전환 기술이 확립되어 있고, 포장 발현분석 단계로 진입하고 있는 중이다. 감귤과 참다래는 형질전환 기술이 일부 개발되었으나, 다양한 품종으로 확대하여 적용하는 단계까지는 이르지 못한 상태이다. 포도 등의 타 과수에서는 형질전환 성공사례가 보고된 바 없으며, 현재 기술개발 연구단계에 머물러 있는 것으로 판단된다. 또한 항생제 선발 대체, 형질전환 대목, 부위 및 생육시기에 따른 조절 기술 개발 등은 실용화를 조기에 앞당기기 위한 선결조건으로 여겨지고 있다.

• Journal of Genetic Medicine
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• 제9권1호
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• pp.11-16
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• 2012

Purpose: To determine a method to improve the efficacy and accuracy of preimplantation genetic diagnosis (PGD) - polymerase chain reaction (PCR), we compared hot start PCR and conventional multiplex nested PCR. Materials and Methods: This study was performed with single lymphocyte isolated from whole blood samples that were obtained from two couples with osteogenesis imperfecta (OI). We proceeded with conventional multiplex nested PCR and hot start PCR in which essential reaction components were physically removed, and we compared the amplification rate, allele dropout rate and nonspecific products. Afterward, we used selective method for PGD. Results: In the two couples, the respective amplification rate were 93.5% and 80.0% using conventional multiplex nested PCR and 95.5% and 92.0% using hot start PCR. The respective mean allele dropout rates for the two couples were 42.0% and 14.0% with conventional multiplex nested PCR and 36.0% and 6.0% with hot start PCR. Conclusion: The results demonstrate that the hot start PCR procedure provides higher amplification rates and lower allele dropout rate than the conventional method and that it decreased the nonspecific band in multiplex nested PCR. The hot start method is more efficient for analyzing a single blastomere in clinical PGD.