• Toxicological Research
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• 제34권1호
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• pp.1-6
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• 2018

The purpose of this study was to detect cell death in the liver of mice treated with thioacetamide (TAA) using fluorescence bioimaging and compare this outcome with that using conventional histopathological examination. At 6 weeks of age, 24 mice were randomly divided into three groups: group 1 (G1), control group; group 2 (G2), fluorescence probe control group; group 3 (G3), TAA-treated group. G3 mice were treated with TAA. Twenty-two hours after TAA treatment, G2 and G3 mice were treated with Annexin-Vivo 750. Fluorescence in vivo bioimaging was performed by fluorescence molecular tomography at two hours after Annexin-Vivo 750 treatment, and fluorescence ex vivo bioimaging of the liver was performed. Liver damage was validated by histopathological examination. In vivo bioimaging showed that the fluorescence intensity was increased in the right upper part of G3 mice compared with that in G2 mice, whereas G1 mice showed no signal. Additionally ex vivo bioimaging showed that the fluorescence intensity was significantly increased in the livers of G3 mice compared with those in G1 or G2 mice (p < 0.05). Histopathological examination of the liver showed no cell death in G1 and G2 mice. However, in G3 mice, there was destruction of hepatocytes and increased cell death. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining confirmed many cell death features in the liver of G3 mice, whereas no pathological findings were observed in the liver of G1 and G2 mice. Taken together, fluorescence bioimaging in this study showed the detection of cell death and made it possible to quantify the level of cell death in male mice. The outcome was correlated with conventional biomedical examination. As it was difficult to differentiate histological location by fluorescent bioimaging, it is necessary to develop specific fluorescent dyes for monitoring hepatic disease progression and to exploit new bioimaging techniques without dye-labeling.

• 한국멀티미디어학회논문지
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• 제17권2호
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• pp.152-159
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• 2014

최근 클라우드 컴퓨팅 기술의 발전에 따라 해저지도 데이터의 효율적인 측정, 기록 및 업데이트하는 분야에서의 원격탐사 기술과 클라우드 컴퓨팅 기술의 활용이 확대되고 있다. 실제 해양 분야에서 수심측정 및 측정 데이터 관리, 유통, 디스플레이 장비 개발 및 보급에 많은 시간과 비용이 발생하고 있다. 이러한 시스템을 개선하고자 실시간 3차원 디스플레이 시스템을 통하여 해당 위치에서의 측정 활동의 중요도를 판단할 수 있으며, 측정 활동의 시간과 비용 감소로 이어질 수 있다. 해양조사선 및 원격탐사 장비 등 다양한 경로를 통해 측정된 데이터는 클라우드 컴퓨팅 기술을 활용하여 처리, 관리된다. 본 논문에서는 원격탐사를 통한 수심측정과 동시에 실시간 3차원으로 디스플레이하는 시스템을 제안한다. 제안된 실시간 3차원 디스플레이 시스템은 해저지형뿐만 아니라 육지의 지형 측량 분야에서도 효과적으로 적용될 수 있다.

• 비파괴검사학회지
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• 제16권1호
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• pp.29-33
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• 1996

핵연료봉의 결함 탐상을 위하여 차동환상형 와전류시험 탐촉자를 설계 및 제작하여, 핵연료봉 시험을 위한 최적 시험 조건을 구하였다. 관통결함, 내부결함, 외부결함을 낸 표준시편에 대하여 와전류시험을 수행함으로써 시험 주파수와 출력 신호의 위상 및 크기에 대한 상관 관계를 구하였다. 이를 토대로 하여 고리원자력 1호기에서 연소한 핵연료봉 G33-N2에 대하여 와전류시험을 수행하여 관통결함 신호를 얻었다. 와전류시험에서 관통결함으로 예측된 위치에서 금속조직시험을 수행하여 얻은 결과는 와전류시험 결과와 잘 일치하였다. 따라서 와전류시험법은 조사핵연료봉의 피복관에 대한 건전성을 평가하는 도구로써 그 신뢰성이 양호함을 실증하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.187-190
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• 2006

In the present study, effects of tree-stream turbulence and surface trip wire on the flow past a sphere at $Re\;=\;0.4\;{\times}\;10^5\;{\sim}\;2.8\;{\times}\;10^5$ are investigated through wind tunnel experiments. Various types of grids are installed upstream of the sphere in order to change the tree-stream turbulence intensity. In the case of surface trip wire, 0.5mm and 2mm trip wires are attached from $20^{\circ}\;{\sim}\;90^{\circ}$ at $10^{\circ}$ interval along the streamwise direction. To investigate the flow around a sphere, drag measurement using a load cell, surface-pressure measurement, surface visualization using oil-flow pattern and near-wall velocity measurement using an I-type hot-wire probe are conducted. In the variation of free-stream turbulence, the critical Reynolds number decreases and drag crisis occurs earlier with increasing turbulence intensity. With increasing Reynolds number, the laminar separation point moves downstream, but the reattachment point after laminar separation and the main separation point are fixed, resulting in constant drag coefficient at each free-stream turbulence intensity. At the supercritical regime, as Reynolds number is further increased, the separation bubble is regressed but the reattachment and the main separation points are fixed. In the case of surface trip wire directly disturbing the boundary layer flow, the critical Reynolds number decreases further with trip wire located more downstream. However, the drag coefficient after drag crisis remains constant irrespective of the trip location.

• 비파괴검사학회지
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• 제30권4호
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• pp.295-301
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• 2010

원자력발전소 탄소강 배관의 유체가속부식은 주요 경년열화 현상이며 발전소의 성능 및 안전성을 저해할 수 있다. 유체가속부식 검사는 보온재 제거 및 설치로 상당한 비용이 수반되므로 최근에 보온재 제거가 필요 없고 원거리 검사가 가능한 유도초음파에 대한 관심이 점점 증가되고 있다. 유체가속부식 검출에 유도초음파 적용이 가능하다면 검사 비용 절감이 예상된다. 본 연구의 목적은 유체가속부식 손상 유무를 확인하고 결함 검출능을 결정하기 위함이다. 본 연구에서는, 실제 유체가속부식 손상 시험편의 엘보우 첫 번째 용접부와 두 번째 용접부의 진폭 감쇄비를 측정하기 위하여 3가지 검사 기법을 사용하였다. 연구 결과, 유체가속부식 손상을 검출하기 위한 최적의 검사 기법과 최소 결함 검출능을 도출하였다.

• 한국광학회지
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• 제13권6호
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• pp.521-529
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• 2002

본 연구에서는 삼차원 공간상에서 절대 좌표를 측정하기 위한 부피 간섭계의 오차원인을 분석하고 각 오차원인이 최종 결과에 미치는 영향을 계산했다. 계산결과 광검출기 배열의 비선형성, 압전소자의 비선형성, 광섬유 내부의 온도변화 둥이 오차의 주요 원인임을 알 수 있다. 제안된 간섭계의 성능을 실험적으로 검증하기 위해 분해능 측정 및 이차원 광학식 스케일과의 비교를 수행했다. 또한 간섭계의 성능을 좀 더 엄밀하게 검증하기 위해 자가보정법을 적용해서 공간상에서 간섭계가 갖는 계통오차를 추출했으며 60mm$\times$60mm$\times$20mm공간에서 최대오차 1 $\mu\textrm{m}$ 이하를 얻었다.

• 한국광학회지
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• 제17권3호
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• pp.223-230
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• 2006

직접 광주파수 변조된 레이저 다이오드를 광원으로 이용하여 공간 선택적 브릴루앙 산란 방식으로 분포형 광섬유 센서를 구성하여 실험하였다. 광주파수가 정현파로 변조된 펌프와 프로브 빛이 광섬유 내로 서로 반대 방향으로 진행하며 중첩되도록 함으로써 광섬유 내 특정 지점에서만 유도 브릴루앙 산란이 발생하도록 하였으며, 변조 주파수를 변화시켜 브릴루앙 이득 피크의 위치를 조절할 수 있었다. 브릴루앙 천이 주파수가 서로 다른 광섬유를 접속한 경우와 광섬유 길이를 따라 온도 분포가 존재하는 경우에 대해 각각 브릴루앙 천이 주파수의 분포를 측정하였다. 브릴루앙 천이 주파수의 온도 변화율은 $1.33MHz/^{\circ}C$로 측정되었다.

• Journal of Korean Neurosurgical Society
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• 제55권3호
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• pp.131-135
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• 2014

Objective : With the growing interests of bacteria as a targeting vector for cancer treatment, diverse genetically engineered Salmonella has been reported to be capable of targeting primary or metastatic tumor regions after intravenous injection into mouse tumor models. The purpose of this study was to investigate the capability of the genetically engineered Salmonella typhimurium (S. typhimurium) to access the glioma xenograft, which was monitored in mouse brain tumor models using optical bioluminescence imaging technique. Methods : U87 malignant glioma cells (U87-MG) stably transfected with firefly luciferase (Fluc) were implanted into BALB/cAnN nude mice by stereotactic injection into the striatum. After tumor formation, attenuated S. typhimurium expressing bacterial luciferase (Lux) was injected into the tail vein. Bioluminescence signals from transfected cells or bacteria were monitored using a cooled charge-coupled device camera to identify the tumor location or to trace the bacterial migration. Immunofluorescence staining was also performed in frozen sections of mouse glioma xenograft. Results : The injected S. typhimurium exclusively localized in the glioma xenograft region of U87-MG-bearing mouse. Immunofluorescence staining also demonstrated the accumulation of S. typhimurium in the brain tumors. Conclusion : The present study demonstrated that S. typhimurium can target glioma xenograft, and may provide a potentially therapeutic probe for glioma.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1344-1354
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• 2022

Laryngeal cancer is one of the highest incidence, most prevalently diagnosed head and neck cancers, making it critically necessary to probe effective targets for laryngeal cancer treatment. Here, real-time quantitative reverse transcription PCR (qRT-PCR) and western blot analysis were used to detect gene expression levels in laryngeal cancer cell lines. Fluorescence in situ hybridization (FISH) and subcellular fractionation assays were used to detect the subcellular location. Functional assays encompassing Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), transwell and wound healing assays were performed to examine the effects of target genes on cell proliferation and migration in laryngeal cancer. The in vivo effects were proved by animal experiments. RNA-binding protein immunoprecipitation (RIP), RNA pulldown and luciferase reporter assays were used to investigate the underlying regulatory mechanisms. The results showed that KIF26B antisense RNA 1 (KIF26B-AS1) propels cell proliferation and migration in laryngeal cancer and regulates the toll-like receptor 4 (TLR4) signaling pathway. KIF26B-AS1 also recruits FUS to stabilize TLR4 mRNA, consequently activating the TLR4 signaling pathway. Furthermore, KIF26B-AS1 plays an oncogenic role in laryngeal cancer via upregulating TLR4 expression as well as the FUS/TLR4 pathway axis, findings which offer novel insight for targeted therapies in the treatment of laryngeal cancer patients.

• 천문학회보
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• 제46권1호
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• pp.54.4-55
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• 2021

The Seoul National University AGN Monitoring Project (SAMP) is a welldesigned long-term AGN reverberation mapping project. SAMP focuses on the luminous AGNs out to z~0.5 with relative long time lags between AGN continuum and broad emission lines and aims to probe the high-end of the AGN broad line region (BLR) size-luminosity (R-L) relation. The pilot observations started in October 2015 for 100 AGNs to confirm the variability and the H and [O III] emission line strengths. Based on the initial variability test, 48 quasars has been continued spectroscopic monitoring since Feb. 2016 with Lick 3m and MDM 2.4m telescopes with a cadence of ~20 days. Supporting photometric monitoring in B and V band was conducted at multiple facilities including the MDM 1.3m, LOAO, and DOAO telescopes with a cadence of ~10 days. By the time of Feb. 2021, we have obtained five years spectroscopic and photometric data. More than 30 AGNs shows significant variability in five-year baseline and 16 of them show well detected lags between B-band and H. Here, we report some examples of SAMP light curves and lag detections using the first five-year data as well as the location of our 16 targets in the AGN BLR R-L relation. These measurements are consistent with the existing R-L relation and located at the high-end. With the coming data, SAMP are hopefully to report more AGNs with well detected lags. Our results demonstrate the general feasibility and potential of long-term reverberation project with medium cadence for luminous AGNs.