Failure of Cephalosporin Treatment for Bloodstream Infection Caused by Apparently Susceptible Klebsiella pneumoniae which Produced DHA-1β-Lactamase Induced by Clavulanic Acid

Kang, Cheol-In,Pai, Hyungjoo,Kim, Sung Han,Kim, Hong-Bin,Oh, Myoung-don,Kim, Eui-Chong,Choe, Kang-Won 대한감염학회 2004 감염과 화학요법 Vol.36 No.3

목적 : AmpC beta-lactamase를 생성하는 Klebsiella pneumoniae 균주가 보고되고 있으나 이에 대한 적절한 치료 항균제 선택에 제한이 있다. Cephalosporin 내성이 유도되는 형질을 지닌 K. pneumoniae에 의한 균혈증이 2례 발생하였다. 혈액에서 분리된 이 균주들의 내정 기전을 확인하고 항균제 감수성의 특성을 알아보고자 하였다. 방법 : NCCLS 지침에 따라 항균제 감수성 검사와 ESBL 확인 검사를 시행하였다. Isoelectric focusing과 PCR을 이용하여 beta-lactamase characterization을 시행하였다. 결과 : 균주들은 DHA-1 AmpC beta-lactamase를 생성하고 있었고 clavulanic acid에 의해 cephalosporin 내성이 유도되었다. 항균제 감수성 검사 결과 내성이 아닌 광범위 cephalosporin을 투여받았으나 환자들은 치료 실패를 경험하였다. 결론 : 이러한 결과들은 DHA-1을 생성하는 K. pneumoniae에 의한 중증 감염증에 광범위 cephalosporin을 투여하는 것은 감수성이 있는 항균제라 하더라도 적절한 항균제 선택이 아닐 수 있음을 시사한다. Backgroud : The therapeutic option is limited for the infections caused by organisms producing plasmid-mediated AmpC beta-lactamases, increasingly identified worldwide. Two sporadic patients with bacteremia caused by K. pnemniae possessing an unusual inducible β-lactam resistant phenotype were found in a university hospital. Materials & Methods : We conducted antibiotic susceptibility test according to NCCLS guideline. Also, we characterized β-lactamase by isoelectric focusing. Results : DHA-1 gene conferred the resistant phenotype. The patients had experienced treatment failure when treated with extended-spectrum cephalosporin. For the isolates the cephalosporin resistance was induced by clawlanic acid (and cefoxitin). Conclusion : Theses results suggest that the extended-spectrum cephalosporins might not provide optimal therapeutic option for inducible DHA-1-producing K. pneumoniae infection, even when the pathogens are susceptible in vitro.

URI-T, 해저 케이블 매설용 ROV 트렌처 개발 및 실해역 성능 검증

강형주(Hyungjoo Kang),이문직(Mun-Jik Lee),조건래(Gun Rae Cho),기건희(Geonhui Ki),김민규(Min-Gyu Kim),이계홍(Ji-Hong Li) 한국해양공학회 2019 韓國海洋工學會誌 Vol.33 No.3

An ROV trencher is a type of heavy-duty work class ROV equipped with high-pressure water jet tools for cutting into the sea floor and burying cables. This kind of trencher is mostly used for PLIB operations. This paper introduces the development of this kind of ROV trencher, which has a 698 kW power system, with a 250 kW hydraulic system and two 224 kW water jet systems. The project was launched in January 2014. After four years of design, manufacturing, and system integration, we carried out two sea trials near the Yeongilman port (about 20–30 m in depth) in Pohang to evaluate the system performance in November 2017 and August 2018. Through tests, we found that most of specifications were satisfied, including a maximum bury depth of 3 m, maximum bury speed of 2 km/h, and maximum forward speed of 1.54 m/s.

6 가 크롬이 백서의 배양섬유모세포에 미치는 세포독성에 관한 연구

강영,반승일,김양일,김형주,정연태 원광대학교 환경과학연구소 1992 環境科學硏究誌 Vol.1 No.1

To investigate the cytotoxicity of Cr^6+, the colorimetric assays of neutral red (NR) and tetrazolium MTT, the measurements of the protein content and the rate of DNA synthesis, and sister chromatid exchange(SCE) analysis were performed in fibroblasts cultured in the medium containing various concentrations of Cr^6+. Electron microscopy of Cr^6+ treated rat fibroblasts was also carried out. The results were as follows ; 1. NR uptake was decreased dose-dependently and NR_90 and NR_50 values of Cr^6+ were 0.2 μM and 1.7μM respectively. 2. Cr^6+ induced the dose-dependent decrease of the activity of mitochondrial succinic dehydrogenase and MTT_90 and MTT_5o valyes were 0.5μM and 5.5 μM respectively. 3, Protein content in rat fibroblasts treated with Cr^6+ decreased dose-dependently. 4. Cr^6+ inhibited DNA synthesis dose-dependently and the rate of DNA synthesis at concentration of Cr^6+ 1.0μM(1.7μM, NR_50) was 33% of the control. 5. Frequency of sister chromatid exchange(SCE) increased dose-dependently and the frequency of sister chromatid exchange at concentration of Cr^6+ 1.0μM was noted to be 8.8 per cell. 6. Light microscopy revealed dose dependent reduction of cell number and decrease in cell size after Cr^6+ treatment. Electron microscopy of cultured fibroblasts treated with Cr^6+ showed dilatation of cisternae of granular endoplasmic reticulum drastic decrease of polyribosomes and increase in number of lysosomes. Above results indicated that Cr^6+ induced severe toxic effect on cultured cell, and suggested that DNA damage by Cr^6+ can be resulted inhibition of cell growth and decrease in cell viability.

Three-Dimensionally Printed Interconnects for Smart Contact Lenses

Kim, Hyungjoo,Kim, Jinseok,Kang, Jaheon,Song, Yong-Won American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.33

<P>One of the ultimate wearable heath-monitoring gears, smart contact lens, requires miniaturized devices compounded and interconnected with each other on the lens for a successful system functioning. Because of the different device thickness, the interconnect patterns need to be three-dimensional (3D) conforming the steps given by the diversified on-lens devices. Also, the patterns should be low-temperature processed and flexible considering the mechanical and thermal property of the lens material. We demonstrate the 3D interconnects electrosprayed on a contact lens platform with Ag-Ag nanowire (NWs) composite ink conforming the steps. Quantitative and informative analysis on the interconnects is presented. Thick polyimide film (12.5 μm) in C-shape is employed as a primary substrate to form the 3D patterns that is to be transferred onto the contact lens. The AgNWs act as frames to support the Ag ion inks printed across the steps. The resultant interconnects realized with the Ag/AgNW composite ink with 0.3 wt % AgNW have the sheet resistance (<I>R</I><SUB>s</SUB>) of 0.396 Ω/□ spanning the height difference of 300 μm. AgNWs also provide durability to the patterns against crack formation and propagation under significant device deformation. Unlike pure Ag pattern which shows the <I>R</I><SUB>s</SUB> changes of 86.1% in the bending condition, the optimally formulated composite pattern shows the suppressed <I>R</I><SUB>s</SUB> change of only 15.2% with a bending radius of 3 mm.</P> [FIG OMISSION]</BR>

지진파 입사방향에 따른 매설관 종방향 응답특성 규명

곽형주(Hyungjoo Kwak),박두희(Duhee Park),이장근(Jangguen Lee),강재모(Jaemo Kang) 한국지반환경공학회 2015 한국지반환경공학회논문집 Vol.16 No.9

이 연구에서는 사실적인 매설관의 종방향 지진 응답특성을 규명하기 위하여 3차원 시간 이력해석이 가능한 쉘-스프링 수치모델을 구축하였으며 지진파 입사방향, 2방향 재하의 영향을 평가하였다. 조화운동을 적용한 결과, 이의 주기는 큰 영향을 주는 것으로 나타났다. 이는 주기가 감소할수록 매설관의 곡률이 증가하며 응답이 증가하기 때문인 것으로 판단된다. 입사방향의 영향을 평가하기 위하여 매설관 축 방향, 수평평면, 그리고 수직평면으로 운동을 재하 하였다. 매설관 축 방향으로 하중을 재하할 경우 휨 변형만을 유발하므로 응답이 매우 작게 계산되었다. 수평 및 수직평면에서 매설관 축 방향과 45°로 재하 하는 경우 축방향 변위가 응답에 지배적인 영향을 주는 것으로 나타났다. 또한 2방향 재하 시, 휨 변형만을 유발하는 요소의 영향이 극히 작으므로 1방향으로만 재하 하는 경우와 결과가 유사하게 계산되었다. 계측기록을 재하 하는 경우에도 응답은 유사하게 계산되었고 1방향 및 2방향 해석의 결과는 크게 다르지 않은 것으로 나타났다. 결과적으로 매설관의 종방향 지진 응답은 축 방향 변위를 유발하는 1방향 재하만으로도 충분히 정확하게 예측할 수 있을 것으로 판단된다. In this paper, a 3D shell-spring model that can perform time history analysis of buried pipelines is used to evaluate the effect of the incident direction of the earthquake motion. When applying harmonic motions, it is shown that the period of vibration has pronounced influence on the response of buried pipelines. With decrease in the period, the curvature of the pipeline and corresponding response are shown to increase. To evaluate the effect of the incident angle, the motions are applied in the direction of the pipleline, horizontal, and vertical planes. When the motion is applied parallel to the direction of the pipeline, it only induces bending strains and therefore, the response is the lowest. Under motions subjected in horizontal and vertical planes at an angle of 45° from the longitudinal axis of the buried pipeline, the axial deformation is shown to contribute greatly to the response of the pipelines. When imposing two-components simultaneously, the calculated response is similar to the case where only single-component is imposed. It is because one component only induces bending strain, resulting in very small increase in the response. The trend of the response is shown to be quite similar for recorded motions. Therefore, it is concluded that use of a single-component is sufficient for estimation of the longitudinal response of buried pipelines.

신용카드 부정사용 방지를 위한 모바일 신용카드 결제방안 연구

김형주 ( Hyungjoo Kim ),강정호 ( Jungho Kang ),이재승 ( Jaeseung Lee ),전문석 ( Moonseog Jun ) 한국정보처리학회 2013 한국정보처리학회 학술대회논문집 Vol.20 No.2

국내 신용카드 이용금액은 민간소비지출 영역에서 62%의 비중을 차지하고 있으며, 이용실적은 2011년 452조원을 기록하였다. 하지만, 신용카드 서명란에 서명을 하지 않은 채 신용카드를 사용하는 경우가 약 33%이상을 차지하고 있으며, 결제 후 서명을 제대로 하지 않는 신용카드 부정사용 사례가 신용카드 결제 중 과반수를 차지하고 있고, 가맹점에서 서명을 확인하는 경우는 전무한 상황이다. 이에 본 논문에서는 Secret Sharing을 기반으로 하는 NFC 모바일 결제방안을 제안하였다. 제안하는 결제방안은 결제 과정에서 부정사용을 원천적으로 차단하였으며, 재사용 공격, 도청 공격 등에 안전하다.

멀티 클라우드 환경에서 브로커 기반 인증 기법

김형주 ( Hyungjoo Kim ),이재승 ( Jaeseung Lee ),강정호 ( Jungho Kang ) 한국정보처리학회 2016 한국정보처리학회 학술대회논문집 Vol.23 No.1

최근 컴퓨터 자원을 효율적으로 사용 가능한 클라우드 컴퓨팅 기술의 활용이 증가하고 있다. 특히, 클라우드 컴퓨팅 환경에서 단순 하나의 클라우드 컴퓨팅 서비스의 제약을 넘어 2개 이상의 클라우드 서비스를 활용할 수 있는 멀티 클라우드에 대한 연구가 활발히 진행되고 있다. 멀티 클라우드란 2개 이상의 클라우드 서비스가 상호 협약을 통해 사용자에게 컴퓨팅 자원을 추가적으로 지원해주는 기술로, 기존 환경에서는 각각의 클라우드 서비스에 인증을 해야 하는 다중 인증 기술이 활용 되었다. 본 논문에서는 기존의 멀티 인증 과정을 단순히 하기 위해, 사용자가 특정 클라우드 서비스에 가입 후, 다른 클라우드 서비스 이용 시 브로커를 활용하여 유저가 추가적인 인증 과정 없이 2개 이상의 클라우드 서비스 이용이 가능한 인증 기법을 제안하였다.

A highly selective dual-channel Cu²⁺ and Al³⁺ chemodosimeter in aqueous systems: Sensing in living cells and microfluidic flows

Kim, Hyungjoo,Rao, Boddu Ananda,Jeong, Jong Woo,Mallick, Sudipta,Kang, Sung-Min,Choi, Joon Sig,Lee, Chang-Soo,Son, Young-A. Elsevier 2015 Sensors and actuators. B Chemical Vol.210 No.-

<P><B>Abstract</B></P> <P>The design and development of fluorescent chemosensors have recently been the focus of considerable attention for the sensitive and specific detection of environmentally and biologically relevant metal ions in aqueous solutions and in living cells. Herein, we report photophysical results for a 1<I>H</I>-pyrrole-2-carboxaldehyde-substituted rhodamine 6G derivative (RCS) that possesses specific binding affinity toward Al<SUP>3+</SUP> and Cu<SUP>2+</SUP> at micromolar concentration levels. In an <I>N</I>,<I>N</I>-dimethylformamide (DMF) and water (v/v=2/8) medium, the RCS chemosensor exhibits a substantially enhanced absorbance intensity at 532nm and a color change from colorless to pink for Cu<SUP>2+</SUP>; it also exhibits significant “off–on” fluorescence at 557nm, accompanied by a color change from colorless to fluorescent-yellow upon binding to Al<SUP>3+</SUP>. The RCS sensor exhibits extremely high fluorescence enhancement upon complexation with Al<SUP>3+</SUP>, and it can be used as a “naked eye” sensor. Through fluorescence titration at 557nm, we confirmed that RCS exhibits a fluorescence response with a remarkable enhancement in emission intensity resulting from the complexation between RCS and Al<SUP>3+</SUP>, whereas no emission appeared in the case of competitive metal ions (Cu<SUP>2+</SUP>, Al<SUP>3+</SUP>, Li<SUP>+</SUP>, Na<SUP>+</SUP>, K<SUP>+</SUP>, Cs<SUP>+</SUP>, Mg<SUP>2+</SUP>, Ca<SUP>2+</SUP>, Fe<SUP>2+</SUP>, Co<SUP>2+</SUP>, Ag<SUP>+</SUP>, Zn<SUP>2+</SUP>, Cd<SUP>2+</SUP>, Hg<SUP>2+</SUP> and Pb<SUP>2+</SUP>) in a DMF and water (v/v=2/8) solution. The reversible ring-opening mechanism of the rhodamine spirolactam induced by Al<SUP>3+</SUP>/Cu<SUP>2+</SUP> binding and the 1:1 stoichiometric structure between RCS and Al<SUP>3+</SUP> were adequately supported by Job-plot evaluation, optical titration and FT-IR analysis. The lowest detection limit for Al<SUP>3+</SUP> is 3.20×10<SUP>6</SUP> M<SUP>−1</SUP> in a DMF and water (v/v=2/8) solution. Al<SUP>3+</SUP>-induced chelation-enhanced fluorescence (CHEF) is associated with spirolactam ring opening of the rhodamine unit. Finally, RCS was successfully applied for the bio-imaging of Al<SUP>3+</SUP> in living HeLa cells and for fluorescence imaging of a microfluidic system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The dual mode sensor RCS for Cu<SUP>2+</SUP> and Al<SUP>3+</SUP> has developed based on rhodamine 6G derivative. </LI> <LI> The sensing properties of RCS originated due to its spiro-lactam ring system. </LI> <LI> The RCS-metal complex structure was confirmed via FT-IR studies. </LI> <LI> RCS was also studied for its potential application to bio-imaging and microfluidic systems. </LI> </UL> </P>

횡 방향 가속 시 법규이탈탑승자세에서 탑승자 머리 및 흉부 거동의 운동학적 특성

강명관(Myeongkwan Kang),김형주(Hyungjoo Kim),김성래(Seonglae Kim),조영근(Youngkuen Cho),정지수(Jisoo Jung),조재민(Jaemin Cho),박해온(Haeon Park),임도형(Dohyung Lim) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11

자동 긴급 조향 회피시스템 작동 시 탑승자 시트 자세 구속 특성 분석

강명관(Myeongkwan Kang),정지수(Jisoo Jung),김성래(Seonglae Kim),조영근(Youngkuen Cho),박해온(Haeon Park),조재민(Jaemin Cho),김형주(HyungJoo Kim),임도형(Dohyung Lim) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5