• 대기
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• 제29권1호
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• pp.105-112
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• 2019

대기 중에 지름이 약 1.68 mm 이상인 물방울이 존재하는 경우, 연직방향으로 주사하는 구름레이더에서 미(Mie) 기법을 사용하여 공기의 연직속도를 구할 수 있다. 이 리뷰논문에서는 강수가 있는 작은 적운 구름에서 구름레이더를 사용하여 공기의 연직속도를 구할 수 있는 방법을 정리하였다. 공기의 연직속도는 첫 번째 미(Mie) 최소치가 이론적으로 가지는 낙하속도와 스펙트럼상에서 첫 번째 미(Mie) 최소치가 실제로 관측된 시선속도와의 차이로 추정할 수 있다. 구름레이더가 항공기에 탑재된 경우에는, 항공기의 운동 및 자세각이, 관측된 도플러속도의 연직성분에 영향을 미치므로 이 항들을 보정하여 공기의 연직속도를 구할 수 있다. 항공용 도플러 레이더의 경우, 미(Mie)기법으로 구한 공기의 연직속도는 구름입자로부터 직접 후방산란 되어 관측된 연직속도 및 항공기 운항시스템으로부터 구한 연직속도와 잘 일치하는 결과를 보여주었다. 구름 레이더로부터 미(Mie) 산란 특징을 이용하여 연직속도를 추정하는 이 기술은 강수 및 비강수 구름시스템에서의 연직속도장 매핑(mapping)에 응용할 수 있다. 또한 여러 고도에서의 항공기 관측을 통하여, 연직속도의 총체적인 구조뿐 만 아니라 폭풍우의 성장, 발달, 소멸 주기(life cycle)를 재구성할 수 있을 것으로 기대된다.

• Clinical Endoscopy
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• 제57권2호
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• pp.253-262
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• 2024

Background/Aims: Hepaticojejunostomy anastomotic stricture (HJAS) is a feared adverse event associated with hepatopancreatobiliary surgery. Although balloon dilation for benign HJAS during endoscopic retrograde cholangiopancreatography with balloon-assisted enteroscopy has been reported to be useful, the treatment strategy remains controversial. Therefore, we evaluated the outcomes and risk factors of recurrent stenosis after balloon dilation alone for benign HJAS. Methods: We retrospectively analyzed consecutive patients who underwent balloon-assisted enteroscopy-endoscopic retrograde cholangiopancreatography for benign HJAS at our institution between July 2014 and December 2020. Results: Forty-six patients were included, 16 of whom had recurrent HJAS after balloon dilation. The patency rates at 1 and 2 years after balloon dilation were 76.8% and 64.2%, respectively. Presence of a residual balloon notch during balloon dilation was an independent predictor of recurrence (hazard ratio, 2.80; 95% confidence interval, 1.01-7.78; p=0.048), whereas HJAS within postoperative 1 year tended to be associated with recurrence (hazard ratio, 2.43; 95% confidence interval, 0.85-6.89; p=0.096). The patency rates in patients without a residual balloon notch were 82.1% and 73.1% after 1 and 2 years, respectively. Conclusions: Balloon dilation alone may be a viable option for patients with benign HJAS without residual balloon notches on fluoroscopy.

• Molecules and Cells
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• 제37권4호
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• pp.330-336
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• 2014

Thymosin beta4 (TB4) has multiple functions in cellular response in processes as diverse as embryonic organ development and the pathogeneses of disease, especially those associated with cardiac coronary vessels. However, the specific roles played by TB4 during heart valve development in vertebrates are largely unknown. Here, we identified a novel function of TB4 in endothelial-mesenchymal transformation (EMT) in cardiac valve endocardial cushions in zebrafish. The expressions of thymosin family members in developing zebrafish embryos were determined by whole mount in situ hybridization. Of the thymosin family members only zTB4 was expressed in the developing heart region. Cardiac valve development at 48 h post fertilization was defected in zebrafish TB4 (zTB4) morpholino-injected embryos (morphants). In zTB4 morphants, abnormal linear heart tube development was observed. The expressions of bone morphogenetic protein (BMP) 4, notch1b, and hyaluronic acid synthase (HAS) 2 genes were also markedly reduced in atrio-ventricular canal (AVC). Endocardial cells in the AVC region were stained with anti-Zn5 antibody reactive against Dm-grasp (an EMT marker) to observe EMT in developing cardiac valves in zTB4 morphants. EMT marker expression in valve endothelial cells was confirmed after transfection with TB4 siRNA in the presence of transforming growth factor ${\beta}$ ($TGF{\beta}$) by RT-PCR and immunofluorescent assay. Zn5-positive endocardial AVC cells were not observed in zTB4 morphants, and knockdown of TB4 suppressed TGF-${\beta}$-induced EMT in ovine valve endothelial cells. Taken together, our results demonstrate that TB4 plays a pivotal role in cardiac valve formation by increasing EMT.