Initial investigation of 3D free form fabrication Using Contour Crafting

Kwon,Hong-kyu 대한안전경영과학회 2007 대한안전경영과학회 학술대회논문집 Vol.2007 No.1

CC 프로세스는 부가 구성물들뿐만이 아니라 전체구조물을 자동화로 만드는 것을 목적으로 한다, 이런 목적을 위하여, 새로운 Trowel 메카니즘이 3D 자유형상을 만들기 위해서 기본적으로 필요하다. 이 논문은 선회하는 Side towel을 사용하여 3D 자유곡면의 제작에 대한 기초적인 조사 및 개념을 보여준다. 특히, ceramics 재료를 이용하여 실험과 개발과정, 및 장래의 적용범위가 상세히 설명된다.

연 X-선 현미경을 이용한 금 나노입자 세포영상

권영만,김한경,김경우,김선희,윤홍화,천권수,강성훈,박성훈,정선관,윤권하 韓國電子顯微鏡學會 2008 Applied microscopy Vol.38 No.3

연 x-선 현미경은 ‘물의 창’ 영역(2.3~4.4 nm)의 파장을 이용하여, 수십 nm의 분해능으로 세포를 파괴하지 않고 살아있는 상태에서 세포의 내부구조를 관찰할 수 있어 가시광선현미경과 전자현미경을 단점을 보완하는 특징을 갖는 세포 생물학 연구에 적합한 현미경이다. 그러나 기존 연 x-선 현미경은 광원으로 방사선 가속기를 이용하기 때문에 사용이 제한적이었다. 이에, 본 연구에서는 2.88 nm의 연 x-선을 광원으로 사용하는 소형 연 x-선 현미경을 이용하여, 내포작용에 의해 금 나노입자를 포획한 HT1080과 MDA-MB 231 세포의 영상을 약 60 nm 분해능으로 획득하였다. 금 나노입자의 세포에 대한 독성을 제거하기 위하여 폴리에틸렌 글리콜을 캡핑하였고, 2.88 nm 파장의 연 x-선에 대하여 충분한 조영효과로 인하여 세포영상에서 뚜렷한 대조도를 나타내었다. 내포작용에 의해 액포에 포함되어 있는 다양한 크기의 금 나노입자 군집을 확인하였으며, 세포내부의 액포의 분포상태도 관찰할 수 있었다. 따라서 고분해능을 가진 소형 연 x-선 현미경을 이용하여 금 나노입자를 세포내의 미세기관이나 특정 단백질에 표지하면 연 x-선에 대한 조영효과의 증가에 의하여 더욱 유용한 정보를 획득할 수 있을 것으로 생각한다. A compact soft x-ray microscope operated in the ‘water window’ wavelength region (2.3~4.4 nm) was used for observing cells with nano-scale spatial resolution. To obtain cellular imaging captured with colloidal gold nanoparticles using a compact soft x-ray microscope. The colloidal gold nanoparticles showed higher contrast and lower transmission more than 7 times than that of cellular protein on the soft x-ray wavelength region. The structure and thickness of the cell membrane of the Coscinodiscus oculoides (diatome) and red blood cells were seen clearly. The gold nanoparticles within the HT1080 and MDA-MB 231 cells were seen clearly on the soft x-ray microscopy. The gold nanoparticles were aggregated within vesicles by endocytosis.

Cytokine and Tumor Environments

Jin Tae Hong1*, Ju Kyung Song, Sun Mi Kwon, Byung Woo Ahn, Youngsoo Kim, Sang Bae Han 충북대학교 동물의학연구소 2012 Journal of Biomedical and Translational Research Vol.13 No.1

Cytokines are known to function as regulatory molecules that can be produced by virtually every nucleated cell type in the body, including lymphocytes, monocytes/macrophages, epithelial cells, fibroblasts, and many others. Cytokines include lymphocyte-derived factors (lymphokines), monocyte-derived factors (monokines), hematopoietic factors (colony-stimulating factors), connective tissue/growth factors, and chemotactic chemokines. Cytokines released in response to infection can affect tumor development in different ways. When exposed to infectious agents, cytokines are secreted by sentinel cells, such as macrophages and dendritic cells. These cytokines include interleukin 1 (IL-1) and tumor necrosis factor-α, as well as others, such as IL-6, IL-12, and IL-18. When released in sufficient quantities, these molecules can cause inflammation. Chronic inflammation is highly associated with tumor initiation, promotion, and progression. In this article, we review the roles and mechanisms of cytokines in tumor development.

芥子 收量檢定試驗區의 크기와 모양에 따른 變異係數(C.V.) 推定

權炳善,李洪宰 順天大學校 1985 論文集 Vol.4 No.1

芥子의 圃場實驗을 遂行함에 있어 適正試驗區의 面積 및 모양을 定하기 위해 實驗한 結果는 다음과 같다. 1. 實驗經費를 고려하지 않은 경우의 適正面積은 10-12㎡의 범위로 推定된다. 2. 分散(S²), 標準偏差(S.D) 및 變異係數(C.V.)는 實驗區 面積이 클수록 낮았고 實驗區모양은 列數를 많게 配置한 正方型에서 變異係數(C.V.)가 낮았다. This study was carried out to determine the optimum plot size and plot shape in Yield trials of mustardseed. Based on the obsservations of 360 basic units, plot size of 10-12㎡ was found to be appropriate for mustardseed yield trials. Lower coefficients of variation indicated the preference of square plot to rectangular plot.

유치 수복물에 따른 주변 법랑질의 탈회 저항성 : QLF를 이용한 연구

권해숙,현홍근,김영재,김정욱,장기택,김종철,한세현,이상훈 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.1

본 연구에서는 유치 수복물의 불소 방출 여부에 따른 주변 법랑질의 탈회 저항성과 재광화 효과를 살펴보고자 하였다. 건전 유전치 48개를 16개씩 임의로 세 군으로 나누어, FiltekTM Z250(1군), F2000(2군), KetacTM N100(3군)을 사용하여 제조사의 지시에 따라 충전하였다. 3일 동안 인공 우식 병소를 유발한 후, 14일 동안 인공 타액에 담가 재광화를 유발하였다. Quantitative light-induced fluorescence(QLF)를 이용하여 실험 단계와 시간에 따른 무기질 소실량(ΔQ)의 변화를 관찰한 결과는 다음과 같다. 1. 탈회가 일어난 인공 우식 병소의 ΔQ 값은 3군, 2군, 1군 순으로 작게 나타났고, 이 중 3군은 1군에 비해 유의한 탈회 저항성을 보였다. 2. 1군, 2군, 3군 모두 재광화 1일 후부터 초기 인공 우식 병소의 ΔQ 값과 비교 시 유의한 차를 보였으며, 관찰 기간 동안 지속적인 증가 양상을 나타내었다. 3. 재광화 속도를 의미하는 Δ(ΔQ)/일 값은 각 군에서 처음 1일 동안 유의성 있게 크게 나타났으며, 그 이후 급속히 감소하였다. 4. 수복 재료에 따른 재광화 정도는 각 군 간에 유의한 차이가 없었다. The objective of this in vitro study was to detect and monitor demineralization and remineralization of primary teeth according to restorative materials using quantitative light-induced fluorescence (QLF). A single bur hole was drilled on the each sound forty eight primary anterior teeth, and the specimens were divided into three groups. The cavity was restored with FiltekTM Z250(Group 1), F2000(Group 2), KetacTM N100(Group 3) following the manufacturer's instructions. The teeth were subjected to the demineralizing buffer for 3 days, and then subjected to a remineralizing buffer for 14 days. The change of mineral loss(ΔQ) according to the stages was evaluated by QLF and the following results were obtained: 1. When demineralization was done, ΔQ was increased as follows. : Group 1 (-110.79 ± 27.77) < Group 2 (-104.84 ± 28.95) < Group 3 (-90.16 ± 21.87) : Resistance to demineralization was statistically significant in Group 3. 2. There was a statistically significant increase in ΔQ of all groups since 1st day of remineralization 3. The rate of remineralization, Δ(ΔQ)/day, showed significant high value in each group on the 1st day then decreased rapidly. 4. There was no statistically significant difference in the degree of remineralization among restorative materials.

0.412 MeV 감마선에 대한 원주형 NaI(Tl) 섬광체의 총 절대검출효율 계산

홍권표,신희성,이상윤,노성기 대한방사선 방어학회 2002 방사선방어학회지 Vol.27 No.4

Total absolute detection efficiencies of a 7.62 cm(dia.) and 7.62 cm(height) cylindrical NaI(Tl) crystal have been calculated for 0.412 MeV r -rays from a source(point, circular disk, square and line type). In this calculation the linear energy-absorption coefficients based on Hubbell's data have been considered and then calculated total absolute detection efficiencies compared with those from Grosjean and Bossaert. Besides, the source axis-to-detector axis shift distance which, could give rise to about 0.05% deviation in the total absolute detection efficiencies has been calculated for a line-type source of 0.5 cm in its length when a source-to-detector distance is 5 cm. It is revealed that the total absolute detection efficiencies obtained in this study are considerably different from those of Grosjean and Bossaert. In addition it is found that the deviation induced due to an imperfect center of a line type source may be within 0.05% if the shifted discrepancy is no larger than 1.74mm.

유전체 공진기를 이용한 개인휴대 통신용 대역통과 필터의 설계 및 구현

권정열,이헌용,홍성용,윤중락 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-

In this paper, the band pass filter for personal communication services was constructed and designed using λ/4 TEM mode dielectric resonators with a (Zr0.65,Sn0.35)ATi1.04O4.04 ceramic of dielectric constant εr=37.8, Qxfo=48.600 temperature coefficient of resonant frequency rf=7ppm/˚C, and Unloaded-Q (Qo) of λ/4 TEM mode dielectric resonator with inner hole size 0.9㎜ and external size 3㎜ using silver electrode is 354.5 at 1950MHz. For the band pass filter design and construction, the design theory and simulation results of band pass filter using J-inverter theory have been studied. The parameters which are evaluated by design theory are practically applied to the filter construction and the simulation results are in agreement with the measured results after fine tunnings.

치료 저항성 환청을 호소하는 정신분열병 환자에 대한 반복 경두개 자기자극(rTMS)과 전기충격요법(Modified ECT)의 연속적인 치료 경험 1례

권준수,전홍진,윤탁 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.4

정신분열병에서 치료에 반응하지 않으며 지속되는 환청은 환자에게 매우 불쾌한 감정을 유발할 수 있으며 환청의 내용에 따라 위험한 경우도 있다. 환청에 대한 기능적 뇌영상 연구 결과로 환청이 정상 청각경로의 비정상적인 활성으로 발생하며, 환청이 들리는 동안에 좌측 상부 측두엽 등이 활성화 된다는 사실을 알게 되었다. 본 증례에서는 항정신병 약물에 대한 치료 저항성 환청을 가진 35세 기혼 여자 환자에 대해서, 좌측 상부 측두엽을 국재화한 후 뇌의 국소적 자극이 가능한 Magstim 200장비와 Double cone shaped coil을 이용하여 1HZ slow wave 반복 경두개 자기자극(rTMS)을 가하였다. 항정신병 약물을 유지한 상태에서 최고 100pulse의 총 14회의 자극을 통해 환청의 주관적인 크기의 30% 감소와 정동의 호전을 관찰할 수 있었다. 반복 경두개 자기자극(rTMS)종료 2주 뒤에 추가적으로 시행된 9회의 전기충격요법(ECT)결과 환청이 빠른 속도로 완전히 소실되었다. 치료저항성 환자의 환청에 대한 치료효과는 rTMS보다 ECT가 효과적임을 알 수 있었다. The Persistent auditory hallucinations may provoke the uncomfortable feeling and be dangerous according to its contents in treatment-resistant schizophrenic patients. Previous functional brain imaging studies on suditory hallucinations reported that the abnormal activations of the normal auditory pathway and the activations of the left upper temporal lobe were found while patients were hallucinationg voices. Base on the these findings, we treated a female schizophrenic patient with persistent auditory hallucinations that were treatment-refractory with rTMS and the ECT continuously while she was on the drug treatment. The total amount of pulses applied in each trial ranged from 240 to 1000pulses. Fourteen trials were done and resulted in decrease by 30% in the subject severity of auditory hallucinations and the improvement of the affect. Two weeks after the completion of rTMS trials, nine trials of ECT were administered which leaded to complete disappearance of auditory hallucinations. This result suggest that ECT is more effective than rTMS in treating persistent auditory hallucinations in treatment-resistant schizophrenic patients.

PCR 핵산 지문법에 의한 Dianthus속의 유연관계분석

홍준식,이문원,강권규 안성산업대학교 2002 論文集 Vol.33 No.-

This study was conducted to evaluate the ressibility of various Dianthus species as ornamental plants based on morphological characteristics and to analyze the genetic relationship among the Dianthus species. D. chinensis, D. curthusiamoum, D. arenorisus, D. superbus and D. barbatus possessing spendour flowering cluster with pink and red color could be suggested for garden plant, with D. caryophyllus having red flower clusters with linear leaf shape for pot flower or garden plant. Twelve oligonucleotide random primers were used to amplify genomic DNA of Dianthus species using polymerase chain reaction. Ninety-five polymorphic bands in the range of 300 to 3,500 bp were obtained from PCR fingerprinting. Similairity matrix of PCR fingerprinting profiles was generated by coefficient value, and the data were subjected to cluster analysis. Thirty-four Dianthus species analyzed were classified into 5 groups with similarity coefficient value of 0.84 and 12 groups with the value of 0.88. PCR fingerprinting rusults showed similar trends as the morphological characteristics of the plants.

Hallimond Tube를 이용한 토양내 P.A.Hs 제거연구

권혁,김홍웅,박규홍 중앙대학교 건설환경연구소 2001 環境科學硏究 Vol.12 No.1

Soil washing or dredged processing is a water-based volume reduction process for mechanically scrubbing a contaminated soil to remove contaminants. In this study, the froth flotation was applied to clean contaminated soil containing poly nuclear aromatic hydrocarbons (P.A.Hs) using a modified Hallimond tube devised by Mulleneers et al. (Colloids and Surfaces A: Physicochemical and Engineering Aspects 151, 293-301, 1999). The effects of air flowrate, particle sizes, and the concentration of frothers such as sodium dodecy1 sulfate on the flotation performance were investigated. Overall recovery was increased with air flowrate and hydraulic entrainment seemed occurred when air flowrate was greater than 1.5 1/min. The highest recovery of 60 to 70% was obtained when 16ml of sodium dodecy1 sulfate was used at 15% of solid concertration in feed. Concentration effect observed in three minutes after the beginning of the experiments was relatively significant at the range of 20 to 150 microns of soil particles. Removal efficiency of phenanthrene was greater than that of naphthalene in case of 180 microns of particles. The first order reaction rate constant of phenanthrene was estimated as 0.12 min-1 using less than 74 microns and 0.21 min-1 using 177 to 300 microns of soil particles. Concentration effect of a more contaminated soil through flotation process will also be helpful in reducing the volume to be treated and the residence time of reactors in the following biological treatment or bioleaching process.