• 한국분말재료학회지
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• 제15권2호
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• pp.125-135
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• 2008

[ $TiO_2$ ] nanotubes for photocatalytic application have been synthesized by hydrothermal method. $TiO_2$ nanotubes are formed by washing process after reaction in alkalic solution. Nanotubes with different morphology have been fabricated by changing NaOH concentration, temperature and time. $TiO_2$ nanoparticles were treated inside NaOH aqueous solution in a Teflon vessel at $110^{\circ}C$ for 20 h, after which they were washed with HCl aqueous solution and deionized water. Nanotube with the most perfect morphology was formed from 0.1 N HCl washing treatment. $TiO_2$ nanotube was also obtained when the precursor was washed with other washing solutions such as $NH_4OH$, NaCl, $K_2SO_4$, and $Na_2SO_3$. Therefore, it was suggested that $Na^+$ ion combined inside the precursor compound slowly comes out from the structure, leaving nanosheet morphology of $TiO_2$ compounds, which in turn become the nanotube in the presence of hydroxyl ion. To stabilize the sheet morphology, the different type of washing treatment solution might be considered such as amine class compounds.

• The Korean journal of internal medicine
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• 제39권3호
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• pp.399-412
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• 2024

Antimicrobial stewardship programs (ASPs) can lower antibiotic use, decrease medical expenses, prevent the emergence of resistant bacteria, and enhance treatment for infectious diseases. This study summarizes the stepwise implementation and effects of ASPs in a single university-affiliated tertiary care hospital in Korea; it also presents future directions and challenges in resource-limited settings. At the study hospital, the core elements of the ASP such as leadership commitment, accountability, and operating system were established in 2000, then strengthened by the formation of the Antimicrobial Stewardship (AMS) Team in 2018. The actions of ASPs entail key components including a computerized restrictive antibiotic prescription system, prospective audit, post-prescription review through quantitative and qualitative intervention, and pharmacy-based interventions to optimize antibiotic usage. The AMS Team regularly tracked antibiotic use, the effects of interventions, and the resistance patterns of pathogens in the hospital. The reporting system was enhanced and standardized by participation in the Korea National Antimicrobial Use Analysis System, and educational efforts are ongoing. Stepwise implementation of the ASP and the efforts of the AMS Team have led to a substantial reduction in the overall consumption of antibiotics, particularly regarding injectables, and optimization of antibiotic use. Our experience highlights the importance of leadership, accountability, institution-specific interventions, and the AMS Team.

• 대한공업교육학회지
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• 제36권2호
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• pp.1-23
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• 2011

본 연구의 목적은 팀 기반 학습모형을 활용한 수업에 참여한 공업계 고등학교 학습자와 교사를 대상으로, 형성적 연구방법론을 활용하여 모형의 강점, 약점, 개선점을 도출하고 이를 통해 모형의 타당성과 통용 가능성을 제고하는 것이다. 팀 기반학습모형은 문제 상황 속에서 학습자 개인의 선행학습과 팀 구성원 간 상호작용을 통해 개인과 팀의 성과를 극대화하기 위한 구조화된 교육방법이다. 이 모형의 개선과 보완을 위해 형성적 연구방법론을 적용하였고, 분석결과, 모형의 강점으로 학습자의 동기와 흥미 유발, 학습자 특성을 반영한 교육 가능, 선행학습을 통한 자신감향상, 반복학습을 통한 개념 이해 등을 파악하였다. 한편 모형의 약점을 보완하기 위한 방안으로 현실적인 교과내용과 방법 편성에 있어서의 한계 극복, 현장감을 높이는 문제은행 확보 필요, 실습 기자재 확충 필요, 학습자의 사전지식과 경험을 고려한 토론 주제 발굴, 구체적인 팀별 활동과 역할 부여 필요 등을 제시하였으며, 개선점으로는 합리적인 팀 구성, 발표 기회의 공정성, 적극적인 참여 독려, 학습자의 선수지식과 태도를 고려한 수준별 학습 계획, 주요한 개념 사전 안내 및 토론 주제선별 등을 제시하였다. 최종적으로 이러한 결과들을 바탕으로 향후 공업계 고등학교에서 적용 가능한 팀 기반 학습모형과 운영방안에 대해 제안하였다.

• 폴리머
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• 제32권1호
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• pp.26-30
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• 2008

추간판 디스크의 섬유륜(AF)조직 재생에 적합한 다양한 담체를 평가하기 위해 천연재료인 소장점막하조직(SIS)과 탈미네랄화된 골분(DBP)을 폴리(락타이드-글리콜라이드) 공중합체(PLGA)와 혼합하여 담체(PLGA/SIS, PLGA/DBP, PLGA/SIS/DBP)를 제조하였으며, PLGA담체, PGA 메쉬, SIS 스폰지와 비교하였다. 제조된 담체의 압축강도 및 AF 세포를 담체에 파종하여 콜라겐 양과 DNA량을 측정하였으며, 이를 누드마우스 피하에 이식 후 적출하여 육안관찰과 조직학적인 평가를 수행하였다. 압축강도 측정에서 PLGA와 유사하게 PLGA/SIS, PLGA/DBP 에서도 충분한 강도를 나타내었다. DNA 증가량에 따른 콜라겐 양은 PLGA/SIS 에서 가장 높게 나타났고, 면역화학 염색을 통해 PLGA/SIS, PLGA/SIS/DBP 에서 글라이코스아미노글라이칸과 콜라겐 발현량이 높음을 확인하였다.

• 폴리머
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• 제33권1호
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• pp.7-12
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• 2009

PLGA미립구는 주사제형과 같은 형태로 조직공학적 응용에 이용할 수 있다. 본 연구에서는 미립구 제조시 에밀젼 형성조건에 대한 영향과 미립구 표면에 세포를 부착시키는 방법에 대하여 연구하였다. BSA를 함유하는 PLGA미립구는 수중유형(O/W)과 수중유중수형(W/O/W) 용매증발법을 이용하여 제조하였다. 미립구의 초기방출효과제어와 PLGA분해의 과정에서 발생되는 지연시간을 개선시키기 위하며 알긴산나트륨을 수상에 용해시켜 사용하였다. 미립구에 부착된 세포의 형태를 전자주사현미경(SEM)을 이용하여 분석하였고 PLGA미립구에 배양된 인간디스크세포의 증식은 MTT분석을 이용하였으며 이를 통하여 PLGA미립구 표면에 세포가 부착되었음을 확인하였다. 본 연구는 BSA가 함유된 알긴산/PLGA미립구를 이용하여 조직공학적 응용이 가능한 주사제형으로서의 가능성을 제안하였다.

• 한국가스학회지
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• 제6권4호
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• pp.8-16
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• 2002

하이드레이트의 존재가 밝혀진 이후 계속적인 실험연구를 통해 평형조건, 열역학적 특성, 구조 kinetics 등 하이드레이트의 기본적 물성에 대한 연구가 지속되어 왔다. 자연 상태에 존재하는 하이드레이트가 미래의 주요한 비재래형 에너지원으로 주목되면서 다공질 저류암 내에서의 하이드레이트 형성 및 해리 메커니즘 규명의 필요성이 요구되고 있다. 이에 본 연구에서는 다공질 암석코어를 사용하여 실험을 수행할 수 있는 실험장비를 제작하여 하이드레이트 형성실험을 수행하였다. 우선, 다공질암 공극 내에서의 하이드레이트 평형조건을 산출하고 기존의 실험결과와 비교함으로써 연구에 사용된 실험장비 및 실험방법의 타당성을 검증하였다. 또한 하이드레이트의 형성실험을 수행하여 압력 및 전기저항의 변화를 통해 다공질암 공각 내에서의 하이드레이트 형성현상을 관찰하였으며, 초기 물포화도가 하이드레이트 형성과정에 미치는 영향을 분석하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1417-1425
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• 2014

The selection of morphologically normal spermatozoa is critical to obtain high breeding performances in boar breeding farms and artificial insemination (AI) centers. Parameters for the selection of semen mainly include total sperm motility, concentration, and morphology. However, these primary parameters are often not reliable for discriminating between normal and abnormal, non-fertilizable spermatozoa. The present study was designed to compare the motion characteristics, fertilization ability using in vitro fertilization (IVF), and acrosome formation of the semen from boars having low (boar number 2012) and normal (boar number 2004 and 2023) breeding performances. The ultimate goal was to identify additional simple and easy criteria for the selection of normal sperm. There was no significant difference between boar 2004 and boar 2023 sperm total motility in computer assisted sperm analysis. However, boar number 2012 semen presented a significantly reduced population of rapid moving spermatozoa and an increased population of slow moving spermatozoa compared to boar numbers 2004 and 2023. Analysis of detailed motion characteristics revealed that sperm from boar number 2012 had significantly reduced motility in progressiveness, average path velocity, straight-line velocity (VSL), curvilinear velocity (VCL), straightness, and linearity. The assessment of the fertilizing ability by IVF also showed that sperm from boar number 2012 showed a fertility rate of 3.4%, whereas sperm from boar number 2023 had a fertility rate of 75.45%. Interestingly, most of the sperm nuclei were found on the peripheral area of the oocytes, suggesting that the sperm from boar number 2012 lacked penetration ability into the oocyte zonapellucida. The acrosome formation analysis using Pisum sativum agglutinin staining demonstrated that the sperm from boar number 2012 had a defect in acrosome formation. Consequently, primary parameters for selecting semen before AI such as motility are not sufficient to select normal and fertilizable spermatozoa. In conclusion, the present study suggests that the acrosome staining and detailed motion characteristics such as progressiveness, VCL, and VSL should be included in determining semen quality together with primary parameters for successful AI and high breeding performance in the swine industry.

• 천문학논총
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• 제27권4호
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• pp.311-316
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• 2012

Lyman break Galaxies are galaxies selected in the rest-frame ultraviolet. But, one important and missing information for these Lyman break galaxies is the amount of dust attenuation. This is crucial to estimate the total star formation rate of this class of objects and, ultimately, the cosmic star formation density. AKARI, Spitzer and Herschel are therefore the major facilities that could provide us with this information. As part of the Herschel Multi-tiered Extragalactic Survey, we have began investigating the rest-frame far-infrared properties of a sample of more than 4,800 Lyman Break Galaxies in the GOODS-North fiels. Most LBGs are not detected individually, but we do detect a sub-sample of 12 objects at 0.7 < z <1.6 and one object at z = 2.0. The ones detected by Herschel SPIRE have redder observed NUV-U and U-R colors than the others, while the undetected ones have colors consistent with average LBGs at z > 2.5. We have analysed their UV-to-FIR spectral energy distributions using the code cigale to estimate their physical parameters. We find that LBGs detected by SPIRE are high mass, luminous infrared galaxies. They also appear to be located in a triangle-shaped region in the $A_{FUV}$ vs. $logL_{FUV}$ diagram limited by $A_{FUV}$ = 0 at the bottom and by a diagonal following the temporal evolution of the most massive galaxies from the bottom-right to the top-left of the diagram. In a second step, we move to the larger COSMOS field where we have been able to detect 80 Lyman break galaxies (out of ~ 15,600) in the far infrared. They form the largest sample of Lyman break galaxies at z > 2.5 detected in the far-infrared. We tentatively name them Submillimeter Lyman break galaxies (S-LBGs).

• 대한수의학회지
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• 제41권1호
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• pp.105-111
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• 2001

We performed this study to determine the effect of Jiegeng(Platycodon grandiflorum), Danggui(Angelica sinensis), Gancao(Glycyrrhiza glabla), Chaihu(Bupleurum falcatnosa), Shoudehuang(Rehmannia glutinosa), Huangqi(Satragalus membranaceus), Muxiang(Saussurea lappa), Yuanzhi(Polygala tenuifolia), Rensen(Panax ginseng) and Baishaoyao(Paeonia lactiflolia), as Oriental radices herbs, on jejunal crypt survival, endogenous spleen colony formation and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of ${\gamma}-radiation$. Jiegeng(p<0.005), Danggui(p<0.0005), Gancao(p<0.005), Chaihu(p<0.05), Muxiang(p<0.05), Rensen(p<0.005) and Baishaoyao(p<0.005) were effective in intestinal crypt survival. Danggui(p<0.05), Chaihu(p<0.05), Shoudehuang(p<0.05), Huangqi(p<0.05), Rensan(p<0.005) and Baishaoyao(p<0.05) increased the formation of endogenous spleen colony. The frequency of radiation induced apoptosis was also reduced by pretreatment with Chaihu(p<0.05), Muxiang(p<0.005), Yuanzhi(p<0.05), Rensan(p<0.05) and Baishaoyao(p<0.05). Although the mechanisms of this effect remain to be elucidated, these results indicated that Danggui, Chaihu, Muxiang, Rensan and Baishaiyao might be a useful radioprotector, especially since it is a relatively nontoxic natural product.

• Current Photovoltaic Research
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• 제3권3호
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• pp.80-84
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• 2015

We suggest new emitter formation method using solid-phase epitaxy (SPE); solid-phase epitaxy emitter (SEE). This method expect simplification and cost reduction of process compared with furnace process (POCl3 or BBr3). The solid-phase epitaxy emitter (SEE) deposited a-Si:H layer by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) on substrate (c-Si), then thin layer growth solid-phase epitaxy (SPE) using rapid thermal process (RTP). This is possible in various emitter profile formation through dopant gas ($PH_3$) control at deposited a-Si:H layer. We fabricated solar cell to apply solid-phase epitaxy emitter (SEE). Its performance have an effect on crystallinity of phase transition layer (a-Si to c-Si). We confirmed crystallinity of this with a-Si:H layer thickness and annealing temperature by using raman spectroscopy, spectroscopic ellipsometry and transmission electron microscope. The crystallinity is excellent as the thickness of a-Si layer is thin (~50 nm) and annealing temperature is high (<$900^{\circ}C$). We fabricated a 16.7% solid-phase epitaxy emitter (SEE) cell. We anticipate its performance improvement applying thin tunnel oxide (<2nm).