• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.123-127
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• 1997

Recently, it is gradually raised necessity that interface is measured accurately and managed in industrial circles and medical world, An Ultrasonic wave transmitted from a focused beam transducer is being expected as a powerful tool for NDE of micro-defect. The ultrasonic NDE of the defect is based on the form of the wave reflected form the interface In this study, regarding to the thickness of film which is in opaque object and thickness measurement was done by MEM-cepstrum analysis of received ultrasonic wave. In measument results, film thickness which is beyond distance resolution capacity was measured accurately. Also, automatically repeated discrimination analysis method can be decided in the category of all kinds of defects on semiconductor package.

• BMB Reports
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• 제46권1호
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• pp.59-64
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• 2013

Signal transducer and activator of transcription 3 (STAT3) and telomerase are considered attractive targets for anticancer therapy. The in vitro anticancer activity of the gold(I) compound auranofin was investigated using MDA-MB 231 human breast cancer cells, in which STAT3 is constitutively active. In cell culture, auranofin inhibited growth in a dose-dependent manner, and N-acetyl-L-cysteine (NAC), a scavenger of reactive oxygen species (ROS), markedly blocked the effect of auranofin. Incorporation of 5-bromo-2'-deoxyuridine into DNA and anchorage-independent cell growth on soft agar were decreased by auranofin treatment. STAT3 phosphorylation and telomerase activity were also attenuated in cells exposed to auranofin, but NAC pretreatment restored STAT3 phosphorylation and telomerase activity in these cells. These findings indicate that auranofin exerts in vitro antitumor effects in MDA-MB 231 cells and its activity involves inhibition of STAT3 and telomerase. Thus, auranofin shows potential as a novel anticancer drug that targets STAT3 and telomerase.

• 대한기계학회논문집
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• 제14권2호
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• pp.413-421
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• 1990

Acoustic emission signals due to leak from circular holes of 0.4, 1, 2 and 4mm diameter and rectangular slits of different geometry having the same cross section as 4mm diameter hole was studied both analytically and experimentally. Acoustic emission signals from a wide-band type transducer were transformed to digital signals through a digital oscilloscope, and $V_{rms}$ and frequency spectrum were obtained by processing digital signals. Relationships between acoustic parameters and fluid mechanical parameters were derived analytically. A quadrapole aerodynamic model was applied in the analysis of leak from the circular holes and $V_{rms}$ was found to be proportional to the root square of leak rate through the circular hole. A modified model based on dipole source mechanism and laminar equivalent diameter was applied in the analysis of leak signals from the rectangular slits. In the case of constant pressure, $V_{rms}$ increased as the laminar equivalent diameter of slit decreased. In the case of constant laminar equivalent diameter, however the result was similar to that for leak from the circular hole. The frequency spectra of leak signals shows the same frequency characteristics irrespective of the pressure difference.rence.

• BMB Reports
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• 제35권6호
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• pp.583-589
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• 2002

The signal transducer and activator of transcription (STAT)1 is a cytoplasmic-transcription factor that is phosphorylated by Janus kinases (Jak) in response to interferon $\gamma$ (IFN-$\gamma$). The phosphorylated STAT1 translocates to the nucleus, where it turns on specific sets of IFN-$\gamma$-inducible genes, such as the interferon regulatory factor (IRF)-1. We show here that gamma irradiation reduces the IFN-$\gamma$ mRNA expression. The inhibition of the STAT1 phosphorylation and the IRF-1 expression by gamma irradiation was also observed. In contrast, the mRNA levels of IL-5 and transcription factor GATA-3 were slightly induced by gamma irradiation when compared to the non-irradiated sample. Furthermore, we detected the inhibition of cell-mediated immunity by gamma irradiation in the allogenic-mixed lymphocytes' reaction (MLR). These results postulate that gamma irradiation induces the polarized-Th2 response and interferes with STAT1 signals, thereby causing the immunosuppression of the Th1 response.

• 한국추진공학회지
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• 제24권2호
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• pp.83-93
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• 2020

압력전달시스템의 주파수응답특성의 효과 때문에 동압센서를 하드웨어에 flush 마운트 형태로 설치해야 한다. 그러나 측정을 위한 포트 주변의 협소한 조건 혹은 고온의 연소가스로부터 센서가 손상되는 것을 막기 위해 벽면 안쪽에 recess 마운트 방식을 설계하기도 한다. 압력전달시스템에서 동압 신호의 왜곡이 발생하기 때문에 동적 응답 특성을 반드시 고려해야 한다. 본 연구에서는 섭동 모델과 2차 축소 모델을 실험치와 비교하였고 주파수응답모델을 선택하기 위한 가이드라인을 제시하였다.

• 동의생리병리학회지
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• 제26권4호
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• pp.437-440
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• 2012

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates various cellular processes such as cell survival, angiogenesis and proliferation. In the present study, we examined that Cryptotanshione(CT), a tanshinone from oriental traditional medicinal herb Danshen (Salvia miltiorrhiza Bunge), had the inhibitory effects on hypoxia-mediated activation of STAT3 in androgen independent human prostate cancer PC-3 cells. CT inhibited the protein expression of hypoxia-inducible factor-1alpha (HIF-$1{\alpha}$) under hypoxic condition. Consistently, CT blocked hypoxia-induced phosphorylation and nuclear accumulation of STAT3. In addition, CT reduced cellular of vascular endothelial growth factor (VEGF), a critical angiogenic factor and a target gene of STAT3 induced under hypoxia. Of note, chromatin immunoprecipitation (ChiP) assay revealed that CT inhibited binding of STAT3 to VEGF promoter. Taken together, our results suggest that CT has anti-angiogenic activity by disturbing the binding STAT3 to the VEGF promoter in PC-3 cells.

• 대한의용생체공학회:의공학회지
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• 제11권1호
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• pp.147-156
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• 1990

A two-dimensional pulsed doppler system for ultrasonic blood velocity doppler signals is studied and implemented. The second-order sampling method and serial data processing procedures are utillized in the sys- tem, which eliminates the untuning problems at phase channels in the quadrature detection method as well as in the channels of parallel data processing. rho digital signal processor used in this system allows a hardware savings and flexible design options. The efficiency of the various mean frequency estimators in the second-order sampling system is examined by computer simulation as a function of the intersequence sample delay time. The temporal delay for the quadrature component is changed from $1/(4f_o){\;}to{\;}3/(4f_o){\;}and{\;}5/(4f_o)$ where to is the center frequency of the transducer, It is found that autocorrelator is the optimum frequency estimator for the second-order sampling: with !he intersequence sample delay of $1/(4f_o){\;}to{\;}3/(4f_o){\;}and{\;}5/(4f_o)$. The qualitative variation and information proportional to blood velocity in the vessel system are obtained in the VIVO experiments.

• 생약학회지
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• 제49권3호
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• pp.225-230
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• 2018

3',4'-Disenecioylkhellactone is one of khellactone-type coumarins isolated from the roots of Peucedanum japonicum Thunb. However, its pharmacological effects are still little understood. In the present study, we investigated the inhibitory effect of 3',4'-disenecioylkhellactone on growth of gastric cancer cells. 3',4'-Disenecioylkhellactone strongly suppressed cell proliferation and induced caspase-mediated apoptosis in AGS human gastric cancer cells. Analysis of phospho-antibody arrays revealed 3',4'-disenecioylkhellactone effectively suppressed signal transducer and activator of transcription 3 (STAT3) tyrosine phosphorylation. 3',4'-Disenecioylkhellactone decreased STAT3 translocation to the nucleus and expression of STAT3 target genes. In addition, we examined the level of STAT3 activation in several gastric cancer cells and found that the inhibition of STAT3 phosphorylation by 3',4'-disenecioylkhellactone was associated with gastric cancer cell proliferation. Taken together, this study provides evidence for the first time that 3',4'-disenecioylkhellactone may be a potential therapeutic agent for the prevention or treatment of gastric cancer.

• 한국어병학회지
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• 제27권2호
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• pp.99-105
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• 2014

Biosensors consist of biochemical recognition agents like antibodies immobilized on the surfaces of transducers that change the recognition into a measurable electronic signal. Here we report a piezoelectric immunosensor made to detect Vibrio vulnificus. A 9MHz AT-cut piezoelectric wafer attached with two gold electrodes of 5mm diameter was used as the transducer of the QCM biosensor with a reproducibility of ${\pm}0.1Hz$ in frequency response. We have tried different approaches to immobilize antibody on the sensor chip. Concerning the orientation of antibody for the best antigen binding capacity, the antibody was immobilized by specific binding to protein G or by cross-linking through hydrazine. In addition, protein G was cross-linked on glutaraldehyde activated immine layer (PEI) or EDC/NHS activated sulfide monolayer (MPA). PEI was found to be more effective to immobilize protein G following glutaraldehyde activation than MPA. However, hydrazine chip showed a better capability to immobilize more IgG than protein G chip and a higher sensitivity. The sensor system was able to detect V. vulnificus in dose dependent manner and was able to detect bacterial cells within 5 minutes by monitoring frequency shifts in real time. The detection limit can be improved by preincubation to enrich the bacterial cell number.

• 비파괴검사학회지
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• 제25권1호
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• pp.9-14
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• 2005

표면 거칠기가 다른 유리시편에 대해 후방 복사된 초음파 세기의 입사각 의존성(프로파일)이 측정되었다. 후방복사 세기와 레일리(Rayleigh) 표면파 속도는 표면 거칠기에 비례하였고 이 경향은 각기 초음파의 산란규칙과 경화현상으로 설명되었다. 후방복사 프로파일의 면적 역시 표면 거칠기에 민감함을 보여 표면상태에 대한 새로운 비파괴적 평가 변수의 가능성을 보였다. 레일리 각 C-스캔 기법은 화상 명도의 반전과 높은 신호대 잡음비(S/N)를 보여주었다.