Layer-by-Layer Doping of Few-Layer Graphene Film

Gü,neş,, Fethullah,Shin, Hyeon-Jin,Biswas, Chandan,Han, Gang Hee,Kim, Eun Sung,Chae, Seung Jin,Choi, Jae-Young,Lee, Young Hee American Chemical Society 2010 ACS NANO Vol.4 No.8

<P>We propose a new method of layer-by-layer (LbL) doping of thin graphene films. Large area monolayer graphene was synthesized on Cu foil by using the chemical vapor deposition method. Each layer was transferred on a polyethylene terephthalate substrate followed by a salt-solution casting, where the whole process was repeated several times to get LbL-doped thin layers. With this method, sheet resistance was significantly decreased up to ∼80% with little sacrifice in transmittance. Unlike samples fabricated by topmost layer doping, our sample shows better environmental stability due to the presence of dominant neutral Au atoms on the surface which was confirmed by angle-resolved X-ray photoelectron spectroscopy. The sheet resistance of the LbL-doped four-layer graphene (11 × 11 cm<SUP>2</SUP>) was 54 Ω/sq at 85% transmittance, which meets the technical target for industrial applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2010/ancac3.2010.4.issue-8/nn1008808/production/images/medium/nn-2010-008808_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn1008808'>ACS Electronic Supporting Info</A></P>

Niacin이 조골세포 분화에 미치는 영향

민현영 ․ 장원구 대구대학교 산업기술연구소 2018 産業技術硏究 Vol.29 No.2

Niacin (Vitamin B3) is a necessary nutrient for humans and animals. This study was conducted to examine the effect of niacin on osteoblast differentiation. Previous study shows that precursor of niacin suppress osteoclast formation. However, the mechanism of niacin in osteoblast differentiation is not well known. In this study we investigated the effect of niacin in osteoblasts. Niacin induced osteogenic differentiation marker genes including distal-less homeobox 5(Dlx5), runt-related transcription factor 2(Runx2), alkaline phosphatase(ALP), and osteocalcin(OC). These results suggest that niacin contributes to osteoblast differentiation by inducing the osteogenic genes.

저혈청 배지에서 인간 전골수세포(HL-60)를 이용한 tPA 생산과 세포사멸기작에 관한 연구

김현구,성기돈,김태호,안주희,함문선,박진서,이현용 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

tPA 생산과 세포 사멸의 연구를 하기 위해서 인간 전골수세포가 배양되었다. 연속 관류 배양하에서 최대 tPA 생산량은 324 ng/ml이며 최대 세포 농도는 5.27×10 exp (6) cells/ml였다. Phorbol ester를 넣었을 때 tPA 생산량은 420 ng/ml까지 향상되었다. 형광 현미경으로 관찰했을 때, apoptosis는 세포 배양 초기부터 중반까지 우세했고 빠른 교반 속도에서도 우세했다. 그러나 necrosis는 세포배양 말기와 동결된 세포가 해동 되었을 때 우세했다. HL-60 was cultivated to produce tPA (tissue-type plasminogen activator) and study the mechanism of cell death. Maximum cell density and tPA production were obtained as 5.27×10 exp (6) cells/ml and 324 ng/ml, respectively under perfusion cultivation. tPA production was enhanced to 420 ng/ml in adding 160 nM of phorbol ester. The cells were gradually differentiated to granulocytes rather than proliferation. By Fluorescent microscope, apoptosis was prevailed except the death phase and in high agitation speed, but necrosis was prevailed in thawed cells and during the latter periods of the cultivation. It was also proved that tPA was most produced in apoptosis. To obtain higher tPA productivity, the cells must be maintained in apoptosis, not necrosis phase when the cells were dying.

온실의 구조적 장애물이 무선통신 성능에 끼치는 특성 규명

권구범, 이재현, 연윤호 忠北大學校 農業科學硏究所 2017 農業科學硏究 Vol.33 No.1

The use of environmental measurement sensors and wireless communication for automatic control in agriculture was increased. The poor reliability of wireless communication were a disadvantage when the system controled in a couple of greenhouses or installed complex structures in a greenhouse. In this study, the effect of structural obstacle in the greenhouse was analyzed on wireless communication. The measurement of wireless communication was calculated by the types of material on obstacle. Because environmental factors such as crops and soil may affect wireless communication in the greenhouse, measurements were conducted in a thermo- hygrostat with constant temperature and humidity. The materials of the obstacle such as vinyl, plywood, acrylic plate, paper box, and heat insulation were performed with different layers (from 1 to 7 layers). The data communication rates between transmission and receiver unit were 100% for ZigBee system in case of 3 vinyls, 2 acrylics and 2 paper boxes. When the number of materials (i.e. vinyl, arcylic, and paper box) was increased, the data communication rates were reduced. However, the data communication rates were partly reduced at more than one of materials in case of plywood and insulation. As the number of layers were increased, the number of loss data were increased and the transmission rate were decreased.

알렉시딘과 차아염소산나트륨의 화학적 상호반응 후 mass spectrometry를 이용한 파라클로로아닐린의검출 분석

김현식,한승현,오소람,임상민,구유,금기연 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.4

근관세척제인 NaOCl과 CHX를 병행 사용하는 경우 적갈색의 발암물질로 알려진 PCA가 생성된다. 본 연구의 목적은 CHX와 유사한 buigunide 계통의 소독제 인 ALX을 NaOCl 과 흔합 반응 시 PCA가 생성되 는지 여부를 mass spectrometry를 이용하여 평가하고자 하였다. 대조군으로는 4% NaOCl 용액과 2% CHX의 혼합용액, 0.5%PCA 용액, 및 1%ALX 용액을 사용하였고 실험군으로는 5가지 농도(1%, 0.5%, 0.25%, 0.125%, 0.0625%)의 ALX 용액과 4% NaOCl의 흔합용액을 질량분석기를 이용하여 mole-cular peak를 분석한 결과 ALX과 NaOCl의 혼합물에서는 PCA(m/w=128)로 보이는 128 피크가 관찰되지 않았다. 또한 용액의 색 변화에서도 ALX이 농도가 높을수록 열은 노랑색을 띄었으나 농도가 낮아질수록 흰색으로 관찰되었으며 어떠한 침전물의 형성도 보이지 않았다. Recent studies demonstrated that the combination of chlorhexidine (CHX) and sodium hypochlorite (NaOCl) resulted in the formation of a precipitate, para-chloroaniline (PCA). Alexdidine (ALX) is a kind of biguanides like CHX, and has stronger detoxification effect against the bacterial virulence factors such as lipoteichoic acid and lipopolysacchardide compared with CHX. The purpose of this study was to determine whether PCA was formed after chemical interaction between ALX and NaOCl using mass spectrometry. Mass spectrometry was performed for the mixture of five different concentrations of ALX (1, 0.5, 0.25, 0.125, 0.0625%) and 4% NaOCl. Results showed that the peak of PCA was not detected in mixed solu tions of ALX and NaOCl in mass spectrometry analysis. The color of mixed solution of ALX and NaOCl after chemical interaction was light yellow to white, but there wasn't any precipitate found.

신주위 공간 및 요근을 침범한 췌장성 가성낭포 1례 : 진단및 경피적 배액술 Diagnosis and Percutaneous Drainage

이현경,오연희,이원재,한동선,오민구,이성우,박수성 동국대학교 경주대학 1993 東國論集 Vol.12 No.-

Pancretic pseudocyst is a well-known complication of pancreatitis and may occur in unusual locations. Involvement of the left perirenal space and psoas muscle is rare. Radiologic findings and management of a surgically proven case of pancreatic pseudocyst extending to left perirenal space and psoas muscle is described.

제조합 대장균에서 과발현된 Citrobacter freundii KCTC2006 유래의 β-Tyrosinase를 이용한 3,4-Dihydroxyphenyl-L-alanine의 생산

이승구,노현수,홍승표,이규종,왕지원,태동년,엄기남,방상구,김영준,성문희 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

재조합 대장균에서 대량발현 시킨 Citrobacter freundii KCTC 2006 유래이 효소 β-tyrosinase를 이용하여 pyrocatechol, sodium pyruvate, ammonium acetate로부터 3,4-dihydroxy phenyl-L-alanine을 생산하기 위한 연구를 수행하였다. 이 효소반응에 적합한 온도 및 pH 조건은 각각 18℃와 8.5로 결정되었고, 반응액 중의 ammonium acetate와 sodium pyruvate의 농도는 각각 300 mM, 50 mM 이상으로 조절하는 것이 적합하였다. Pyrocatechol의 경우는 20 mM에서 가장 높은 반응성을 나타냈으나, 기질을 반복적으로 첨가하며 장시간 동안 효소반응을 수행하는 경우에는 pyrocatechol의 고갈을 피하기 위하여, 20 mM에서 50 mM 사이로 조절하였다. 한편, 반응액 중에 ethanol을 10% 첨가한 경우에는 반응속도가약 20% 증가하였다. 이상과 같은 효소반응특성에 기초하여 조제한 기질용액에 β-tyrosinase를 1 unit/㎖ 농도로 가하고, pyrocatechol과 pyruvate가 고갈되지 않도록 간헐적으로 첨가하면서 효소반응을 수행한 결과, 24시간 만에 85.2%의 수율로 31.6g/ℓ의 3,4-dihydroxyphenyl-L-alanine를 생산할 수 있었다. By using the β-tyrosinase of Citrobacter freundii KCTC2006, which was cloned and overexpressed in Escherichia coli, 3,4-dihydroxy phenyl-L-alanine (L-DOPA) was synthesized efficiently from pyrocatechol, sodium pyruvate, and ammonium acetate. Optimal temperature and pH for the reaction were determined to be about 18℃ and 8.5, respectively. The effects of substrate concentrations were also examined at different concentrations of ammonium acetate, sodium pyruvate, and pyrocatechol. Ammonium acetate and sodium pyruvate increased the reaction rate until the concentrations reached to 300 mM and 50 mM, respectively. Although pyrocatechol showed the optimal concentration at 20 mM, it was controlled between 20 mM and 50 mM to avoid the depletion of substrate during the enzymatic synthesis. Based on above results, a reaction medium for the production of L-DOPA was prepared and incubated with 1 unit/㎖ of β-tyrosinase. Pyrocatechol and sodium pyruvate was added to the reaction solution intermittently to avoid the substrate depletion during the enzymatic reaction. After 24 hour of reaction, 31.6 g/ℓ L-DOPA was accumulated in the reaction solution as soluble and precipitated ones and the conversion yield was about 85.2%.

p-Anisaldehyde가 조골세포 분화에 미치는 영향

김경민 ․ 이도원 ․ 김현준 ․ 김아랑 ․ 장원구 대구대학교 산업기술연구소 2018 産業技術硏究 Vol.29 No.2

p-Anisaldehyde is a natural fragrance extracted from Pimpinella anisum L., and used as a preservative. This study examined the effect of p-anisaldehyde on osteoblast differentiation. First, cytotoxicity tests were carried out after examining the concentrations that did not show toxicity to the cells. The expression of osteoblast differentiation marker gene was confirmed by RT-PCR and was not effective in the treatment with p-anisaldehyde alone. However, p-anisaldehyde decreased the expression levels of inhibitor of differentiation-1 (Id1), distalless related homeobox (Dlx5), and runt-related transcription factor 2 (Runx2), which are osteogenic differentiation marker genes, which are increased in osteogenic condition. alkaline phosphatase (ALP) activity was also confirmed by ALP staining that p-anisaldehyde reduced ALP activity. These results show that p-anisaldehyde is effective in reducing osteoblast differentiation.

공동주택 바닥충격음 적정 평가어휘 조사에 관한 연구

송민정,송혁,이태강,기노갑,박현구,김선우 대한건축학회 2004 대한건축학회논문집 Vol.20 No.5

The "Sound Classification System on Floor Impact Sound Insulation Performance" is being studied in Korea. For that study, vocabularies appropriate for evaluation and reporting are needed. In this study, adequate words for evaluating floor impact sound have been extracted by reviewing the existing vocabularies and augmenting this with the results of a questionnaire prepared especially for apartment dwellers. As a result of this study, followings are suggested. 1) The heavy impact sound sources are more highly ranked than light impact ones. And the louder sound sources are the more accumulated points. 2) Highly ranked vocabularies are different for each source. 3) Floor impact sound evaluating words such as ‘Annoying’, ‘Disagreeable’, ‘Strident’, ‘Disturbed’, and ‘Dissonant’ are highly ranked. ‘Annoying’ is the word most accurately expressing the subjects' unpleasant feeling of domestic floor impact noise. 4)‘Unpleasant’, ‘Noisy’, ‘Irritating’, ‘Annoying’ are main unpleasant factors to floor impact sounds occurring in our domestic apartment houses.

The reconstruction of extracellular matrix in the reproductive organs during pre-eclampsia and the influence of testosterone

Hyeon-Gu Kang,Sung-Min An,Min Jae Kim,Da Som Kim,So Young Kim,Da Hee Kang,Seung Chul Kim,Beum-Soo An 한국실험동물학회 2020 한국실험동물학회 학술발표대회 논문집 Vol.2020 No.2