반코마이신 내성 장내구균 분리 환자에서 황색포도알균의 내성

김동욱,신선혜,김혜진,류선,이선희,장철훈,김영대,곽임수 대한감염학회 2004 감염과 화학요법 Vol.36 No.1

목적 : Vancomycin-resistant enterococci (VRE)로부터 S. aureus로의 vacomycin 내성 유전자의 전파는 오래전부터 예견되어져 왔으며 큰 걱정거리로 남아있다. 최근에 vanA 유전자를 가지고 있는 vancomycin-resistant S. aureus 2주가 미국에서 분리되었다. 이 연구의 목적은 VRE를 보균하고 있는 환자들에서 S. aureus 보균양상과 항균제 내성을 알아보는데 그 목적이 있다. 재료 및 방법 : 2001년 1월부터 2001년 12월까지 부산대학교병원에 입원하였던 환자들 중 임상검체에서 VRE가 분리된 환자 7명과 2001년 9월부터 12월까지 외과 중 환자실에 입원하였던 환자들 중 VRE 감시배양을 시행하였던 20명의 환자들을 대상으로 하였다. 환자들은 전비공, 액와부, 회음부, 직장에서 매주 면봉으로 검체를 채취하였다. 선별배지에서 검체를 배양하여 S. aureus를 분리하였고 원판 확산법을 이용하여 methicillin 감수성을 측정하였다. Broth microdilution 법으로 vancomycin MIC를 측정하였다. 결과 : 총 27명에서 73회의 방문과 292회의 배양이 시행되었으며 총 67주의 S. aureus가 분리되었다. 이중 64주(95.5%)가 methicillin 내성이었다. 전비공 MRSA 보균율은 VRE를 보균하고 있었던 환자는 19명 중 11명(58%)에서, VRE를 보균하지 않았던 환자는 8명 중 3명(37.5%)으로 VRE 보균자에서 보균율이 더 높았다. 총 64주의 MRSA의 vancomycin MIC의 분포는 0.5-2㎍/mL였으며 2㎍/mL를 초과하는 균주는 발견되지 않았다. 64주 중 vancomycin MIC가 1㎍/mL인 균주가 54주(84.4%)로 가장 많았으며 2㎍/mL 6주(9.4%), 0.5㎍/mL 4주(6.3%)의 순이었다. 결론 : VRE 환자에서 S. aureus의 보균율은 비보균자 보다 높았으며 분리된 균주들은 대부분 MRSA였다. VRSA 균주는 발견되지 않았다. Background : The transfer of vancomycin resistance from vancomycin-resistant enterococci (VRE) to Staphylococcus aureus has been predicted. The purpose of this study is to determine the prevalence and antibiotics resistance of S. aureus among patients colonized with VRE. Methods : Between January 2001 and December 2001, a prospective study was performed at Pusan National University Hospital on 27 patients. Surveillance swabs from nasal cavity, axilla, perineum, and rectum were obtained at weekly intervals. Methicillin susceptability of S. aureus was determined by oxacillin disk diffusion test and minimum inhibitory concentration (MIC) for vancomycin by microdilution broth test. Results : Total of 292 swab cultures were performed and 67 S. aureus isolates were collected. 64 isolates (95.5%) were resistant to methicillin. The prevalence of nasal MRSA carrier in 19 patients colonized with VRE was higher than that in 8 patients not colonized with VRE (58% vs. 37.5%). In 64 MRSA isolates, MIC (㎍/mL) for vancomycin ranged from 0.5 to 2. No isolates with MIC >2 ㎍/mL were observed. MIC of 1 ㎍/mL was shown (observed) in 54 isolates, 2 ㎍/mL in 6 isolates, and 0.5 ㎍/mL in 4 isolates. Conclusion : The prevalence of S. aureus with colonization of VRE is higher than that without colonization of VRE. Most of S. aureus isolates were resistant to methicillin. VRSA isolates were not observed.

이동 애드 혹 네트워크에서의 환경적응형 QoS AODV 라우팅 프로토콜에 관한 연구

裵振勝,宋東勳,吳世德,鄭燦赫,金玄郁,李光培,文泰洙,郭承郁,河載承 明知大學校 産業技術硏究所 2004 産業技術硏究所論文集 Vol.23 No.-

In this paper, we propose a bidirectional mobile Ad Hoc routing protocol based on AODV(ad-hoc on-demand distance vector routing) with QoS(quality of service) support. At presence, wireless mobile communication focuses on how to efficiently support mobility of users more than QoS guarantee. However, in order to satisfy requirement of various applications which have been or will be served, QoS guarantee between end points is a very important issue. The existing AODV routing protocol is implemented to use only BE (Best Effort) service. However, actual wireless mobile environment requires to reduce a waste of communication resources and meet with the real-time change of data paths by setting up routes with QoS support, considering available communication resources at each node in advance. Therefore, in this thesis, we propose an adaptive QoS support method using hello message in order to rapidly meet with the change of available communication resources and to smoothly perform route maintenance. For performance evaluation, we analyzed the average data reception rate. At that time, we used evaluation parameters such as node's mobility-stop time, hello message period, and packet priority, considering the node's mobility and the number of best effort/QoS data flows. As results, we found that with our proposed method the average data reception rate was increased 16.293%, 15.914%, 17.238% for 300 mobility-stop second case and 4.809%, 4.264%, 2.956% for 300 mobility-stop second case.

한방 적용을 위한 측면 얼굴의 특징 추출

조동욱(Dong Uk Cho),장언동(Oeun Dong Jang),곽기헌(Ki Heon Kwak),김지철(Ji Cheol Kim) 한국통신학회 2005 한국통신학회 학술대회논문집 Vol.2005 No.6

공간 데이터 웨어하우스에서 데이터큐브 구축을 위한 GML 기반의 스키마†

곽동욱 ( Dong-uk Kwak ),유병섭 ( Byeong-seob You ),이동욱 ( Dong-uk Lee ),이재동 ( Jae-dong Lee ),배해영 ( Hae-young Bae ) 한국정보처리학회 2006 한국정보처리학회 학술대회논문집 Vol.13 No.1

본 논문에서는 OGC 의 공간 정보 인코딩 표준 명세인 GML 을 기반으로 공간 데이터 웨어하우스를 구축하는 스키마를 제안한다. GML 기반의 스키마는 비공간 정보뿐만 아니라 공간 정보에 대한 정의가 가능하다. 그리고 XML 스키마를 이용하여 전체 큐브 스키마, 차원 스키마 및 사실테이블에 대한 스키마 정의의 예를 보인다. 따라서 제안 기법은 GML 을 이용하여 이질적인 시스템간의 데이터 통합이 용이하고, 비공간 정보뿐만 아니라 공간 정보의 활용이 가능하다. 그리고 공간 데이터 웨어하우스의 개념계층 관계에 대한 표현이 용이하고 구조에 대한 이해가 쉽다.

방청용 유/무기 하이브리드 코팅제의 제조

이동욱 ( Dong Uk Yi ),김동원 ( Dong Won Kim ),백재호 ( Jae Ho Baek ),곽삼탁 ( Sam Tak Kwak ),문명준 ( Myung Jun Moon ) 한국화상학회 2013 한국화상학회지 Vol.19 No.3

Sol-gel 코팅제는 금속 소재의 부식 억제를 위해 다양한 분야에서 활용되어지고 있다. 본 연구의 유/무기 하이브리드 코팅제는 methyl trimethoxy silane 과 alumina sol에 3-glycidyloxypropyl trimethoxy silane을 혼합하여 제조하였다. 3-glycidyloxypropyl trimethoxy silane 의 함량에 따라 sol-gel 공정으로 도장된 박막의 내식성, 경도, 그리고 열안정성을 조사하였다. Electrochemical impedance와 potentiodynamic polarization의 측정 결과로부터 도막의 내식성이 3-glycidyloxypropyl trimethoxy silane의 도막 내 장거리 상호작용에서 기인한 접착력 증가와 crack-free 도막의 형성에 의해 개선되었음을 알 수 있었다. Sol-gel coating has been widely utilized for enhancing the corrosion resistance of metal substrate. The organic-inorganic hybrid coatings were prepared by mixing the methyl trimethoxy silane and alumina sol with 3-glycidyloxypropyl trimethoxy silane. The corrosion resistance, hardness, and thermal stability of thin film coated by sol-gel method was investigated according to the adding amounts of 3-glycidyloxypropyl trimethoxy silane. From electrochemical impedance and potentiodynamic polarization measurement, it was found that the corrosion resistance of coating was improved by the adhesion increase and the crack-free film that induced by the long-range interaction of 3-glycidyloxypropyl trimethoxy silane within coating.

Design of PIFA With Metamaterials for Body-SAR Reduction in Wearable Applications

Kwak, Sang il,Sim, Dong-Uk,Kwon, Jong Hwa,Yoon, Young Joong IEEE 2017 IEEE transactions on electromagnetic compatibility Vol.59 No.1

<P>This letter proposes a planar inverted-F antenna (PIFA) with an artificial magnetic conductor (AMC) structure for body specific absorption rate (SAR) reduction in a wideband-code-division-multiple-access band. As wireless devices such as wearable phones and smartwatches become more common, health risks originating from electromagnetic waves generated by devices worn on the body have become an important issue. AMC structures are a type of metamaterial that can act as a perfect magnetic conductor and control the radiation pattern of an antenna. Thus, an antenna with an AMC structure is capable of preventing hazardous electromagnetic fields being emitted in the direction of the body. The S-parameters, radiation patterns, total radiated power values, and SAR values of such a designed structure are presented. The results demonstrate a 43.3% reduction in the SAR value at the center frequency. Thus, the human body can be protected from electromagnetic waves using metamaterials.</P>

Anti-inflammatory actions of plant-derived multiple monoclonal antibody CO17-1A × BR55 related with anti-cancer effects in AOM/DSS-induced colorectal cancer mouse via down-regulating of ERK1/2

Kwak, Dong Hoon,Heo, Sung Yun,Kim, Chang-Hyun,Kim, Ji-Su,Kim, Sun-Uk,Chang, Kyu-Tae,Choo, Young-Kug The Korean Society for Integrative Biology 2016 Animal cells and systems Vol.20 No.4

Plant-derived multiple monoclonal antibody (mAb) <TEX>$CO17-1A{\times}BR55$</TEX> (<TEX>$mAb^P$</TEX> <TEX>$CO17-1A{\times}BR55$</TEX>) produced in transgenic tobacco plants were cross-pollinated with mAb CO17-1A and mAb BR55. Human anti-colorectal cancer multiple mAb <TEX>$CO17-1A{\times}BR55$</TEX> was cloned using pBI121 vector. Mice were given a single intraperitoneal injection of azoxymethane (AOM) with 10 mg/kg body weight. Starting 1 week after the injection, mice received 2% dextran sulfate sodium (DSS) in the drinking water for 1 week. In addition, the mice were injected intraperitoneal with mAbs dissolved in phosphate buffered saline (<TEX>$100{\mu}g/mouse$</TEX>) twice per week for 4 weeks. Apoptotic cell death, expression of pro-apoptotic proteins, activity of inflammatory cytokines and ERK pathway phosphorylation were assayed by Western blot and TUNEL kit. <TEX>$mAb^P$</TEX> <TEX>$CO17-1A{\times}BR55$</TEX> meaningfully and efficiently suppressed the development of AOM/DSS-induced colorectal inflammation and colorectal tumors, as determined by a reduced activation of inflammatory cytokines, number of colorectal tumor-induced mouse, number of tumor per mouse colon than other mAbs. Cell death by apoptosis was much increased in the <TEX>$mAb^P$</TEX> <TEX>$CO17-1A{\times}BR55$</TEX>-treated tumor compared with negative control. Apoptotic cell death and expression of pro-apoptotic proteins including Bax and cleaved caspase-3 were highest in treatment with <TEX>$mAb^P$</TEX> <TEX>$CO17-1A{\times}BR55$</TEX>. In addition, mAbP <TEX>$CO17-1A{\times}BR55$</TEX> was meaningfully decreased the expression of inflammatory cytokines, including COX-2, iNOS, p50 and p65, but the expression of <TEX>$PPAR{\gamma}$</TEX> was significantly increased compared with AOM/DSS-induced carcinogenesis negative control. Moreover, <TEX>$mAb^P$</TEX> <TEX>$CO17-1A{\times}BR55$</TEX> meaningfully repressed the ERK1/2 phosphorylation in AOM/DSS-induced colorectal tumors. Therefore, our results suggest that multiple <TEX>$mAb^P$</TEX> <TEX>$CO17-1A{\times}BR55$</TEX> have meaningful effects of anti-inflammation related with the anti-carcinogenesis in AOM/DSS-induced colorectal tumor by inhibition of ERK1/2 phosphorylation.

Electrical bistabilities and memory mechanisms of organic bistable devices fabricated utilizing SnO2 nanoparticles embedded in a poly(methyl methacrylate) layer.

Kwak, Jin Ku,Yun, Dong Yeol,Son, Dong Ick,Jung, Jae Hun,Lee, Dea Uk,Kim, Tae Whan American Scientific Publishers 2010 Journal of Nanoscience and Nanotechnology Vol.10 No.11

<P>Organic bistable devices fabircated utilizing SnO2 nanoparticles embedded in a poly(methyl methacrylate) (PMMA) polymer layer were formed by using a spin coating method. Transmission electon microscopy images and photoluminescence spectra showed that synethized SnO2 nanoparticles were randomly distributed in the dibutyl ehter solution. Current-voltage (I-V) measurements on the Al/SnO2 nanoparticles embedded in PMMA layer/ITO devices at 300 K showed current bistability due to the existence of SnO2 nanoparticles. Current-time (I-t) results showed the memory retention characteristic of the device. Carrier transport mechanisms of the device are described on the basis of the I-V experimental results and electronic structures.</P>

GM1 Induced the inflammatory response related to the Raf-1/MEK1/2/ERK1/2 pathway in co-culture of pig mesenchymal stem cells with RAW264.7

Kwak, Dong Hoon,Seo, You Na,Lee, Ju Hyoung,Park, Soon Ju,Cho, Young Ho,Kim, Ji-Su,Kim, Sun-Uk,Choo, Young-Kug ZOOLOGICAL SOCIETY OF KOREA 2018 ANIMAL CELLS AND SYSTEMS Vol.22 No.3

<P><B>ABSTRACT</B></P><P>Pig-human xenotransplantation can trigger cell-mediated immune responses. We explored the role of gangliosides in inflammation related to immune rejection in xenotransplantation. Co-culture of xenogeneic cells (pig-MSCs and RAW264.7) was used to emulate xenotransplantation conditions. MTT assay results indicated that cell viability was significantly decreased in pADMSCs co-cultured with RAW264.7 cells. GM1 and GM3 were highly expressed in pADMSCs co-cultured with RAW264.7 cells. pADMSCs co-cultured with RAW264.7 cells strongly expressed pro-inflammatory proteins such as COX-2, iNOS, p50, p65, pIκBα, and TNF-α. GM1-knockdown pADMSCs co-cultured with RAW 264.7 cells did not show significantly altered cell viability, but pro-inflammatory proteins were markedly inhibited. Co-culture of pADMSCs with RAW264.7 cells induced significant phosphorylation (p) of JNK1/2 and pERK1/2. However, pERK1/2 and pJNK1/2 were decreased and MEK1/2 and Raf1 were suppressed in GM1-knockdown pADMSCs co-cultured with RAW264.7 cells. Thus, the Raf-1/MEK1/2/ERK1/2 and JNK1/2 pathways were significantly upregulated in response to increases of GM1 in co-cultured xenogeneic cells. However, the inflammatory response was suppressed in co-culture of GM1-knockdown pADMSCs with RAW264.7 cells via down-regulation of the Raf-1/MEK1/2/ERK1/2 and JNK1/2 pathways. Therefore, the ganglioside GM1 appears to play a major role in the inflammatory response in xenotransplantation via the Raf-1/MEK1/2/ERK1/2 and JNK1/2 pathways.</P>

Relationship between ganglioside GD1a and inflammatory response in the coculture of human endothelial cells with porcine endothelial cells

Kwak, Dong Hoon,Lee, So Dam,Lee, Ju-Hyoung,Kim, Ji-Su,Kim, Sun-Uk,Chang, Kyu-Tae,Choo, Young-Kug Taylor Francis 2015 Animal cells and systems Vol.19 No.2