• 대한임상검사과학회지
• /
• 제47권4호
• /
• pp.298-305
• /
• 2015

최근 종양을 극복하고자 하는 새로운 접근 방법가운데 하나로, 종양세포내에 발현되는 줄기세포 전사인자들(Oct4, Sox2, KLF4 and Lin28)을 억제하여 종양을 치료하는 연구들이 증가하고 있다. 본 실험은 미분화 전사인자를 표적(조절)하는 microRNA-126을 이용하여 난소종양세포들(6종: HSC832(t)c, Ovcar3, Skov3, PA-1, TOV21G and Tov112D)들 생존과 성장에 어떠한 생물학적 변화를 유도하는지 연구하였다. Scramble과 microRNA-126를 난소종양세포들에 처리 후 세포모양 관찰결과 Skov3를 제외한 난소 종양세포들에서 형태학적 모양 변성과 부유현상을 관찰하였다. CCK-8을 이용한 세포분열능 분석에서 Skov3를 제외한 난소 종양세포들의 분열능력이 점차적으로 감소되는 것을 확인하였다. 특히 Tov112D, Tov21G and PA-1에서 각 시간대별로 뚜렷한 세포분열 능력 감소를 확인할 수 있었다. RT-PCR결과 미분화 전사인자들(Sox2, Lin28)의 발현감소를 확인할 수 있었다. 이러한 결과들은 microRNA-126이 다양한 난소 종양세포들을 표적하여 세포분열능과 사멸을 유도할 수 있는 가역적 환경(유전자 발현조절)을 제공함과 동시에 임상 치료에 대한 분자생물학적 단서를 제공할 수 있을 것이다.

• International Journal of Vascular Biomedical Engineering
• /
• 제1권2호
• /
• pp.30-35
• /
• 2003

Flow characteristics of blood flow in a micro channel were investigated experimentally using a micro-PIV (Particle Image Velocimetry) velocity field measurement technique. The main objective of this study was to understand the real blood flow in micron-sized blood vessels. The Reynolds number based on the hydraulic diameter of micro-channel for deionized (DI) water was about Re=0.34. For each experimental condition, 100 instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity. In addition, the motion of RBC (Red Blood Cell) was visualized with a high-speed CCD camera. The captured flow images of nano-scale fluorescent tracer particles in DI water were clear and gave good velocity tracking-ability. However, there were substantial velocity variations in the central region of real blood flow in a micro-channel due to the presence of red blood cells.

• 반도체디스플레이기술학회지
• /
• 제14권3호
• /
• pp.23-26
• /
• 2015

A seam carving based micro-crack detection method is proposed which aims at detecting the micro-crack regions in heterogeneously textured surface of polycrystalline solar cells. By calculating the seam which is a connected path of low energy pixels in the image, the micro-crack regions can be detected. Experimental results show that the proposed seam carving based micro-crack detection method has superior efficiency in detecting the micro-crack without background noise pixels and the algorithm's computation time is less than the conventional algorithm.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권12호
• /
• pp.7081-7084
• /
• 2013

MicroRNAs have been demonstrated to regulate proliferation and apoptosis in many types of cancers, but biological functions in osteosarcomas remain relatively unknown. Here, we found expression of miR-802 to be up-regulated in osteosarcoma tissues in comparison with adjacent normal tissues. Enforced expression of miR-802 was able to promote cell proliferation in U2OS and MG63 cells, while miR-802 antisense oligonucleotides (antisense miR-802) inhibited cell proliferation. At the molecular level, our results further revealed that expression of p27, a negative cell-cycle regulator, was negatively regulated by miR-802. Therefore, the data reported here indicate that miR-802 is an important regulator in osteosarcoma, our findings contributing to a better understanding of important mis-regulated miRNAs in this tumour type.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
• /
• pp.597-599
• /
• 1995

We have analyzed the dielectrophoretic(DEP) force on a cell in a micro planar electrode structure. We fabricate a micro planar electrode structure using micro machining technology and measure the motion of a cell that is accelerated by DEP force. DEP force on a cell is calculated by curve fitting the motion of a cell. Radish and yeast are used for the experiment. In case of radish, DEP force is increased as the voltage and the frequency is increased, and in case of yeast, DEP force is increased only as the voltage is increased DEP force on a yeast does not vary when the frequency varies from 1 MHz to 3 MHz. The result will be helpful to the manipulation of cells using DEP force.

• 농업과학연구
• /
• 제14권2호
• /
• pp.197-204
• /
• 1987

양버들의 explant soure에 따른 현탁배양(懸濁培養) 세포(細胞)의 생장(生長)과 생장기간(生長其間)에 따른 배양세포내(培養細胞內) 질소함량(窒素含量) 변화(變化), plating방법(方法)에 따른 micro-callus 형성능력(形成能力), 배양배지(培養培地)의 종류(種類) 및 생장조절물질(生長調節物質), 질소량(窒素量)에 따른 현탁배양세포(懸濁培養細胞)의 생장(生長)과 고체배지(古體培地)에 plating하였을 때 micro-callus 형성(形成)을 조사(調査)하여 다음과 같은 결과(結果)를 얻었다. 1. 절간조직(節間組織)과 엽병조직(葉柄組織)에서 유래(由來)된 callus를 재료(材料)로 하여, 현탁배양(懸濁培養)하였을 때 세포(細胞)의 생중량(生重量)과 packed cell volume은 거의 비슷하게 증가(增加)하였으며, 배양후(培養後) 12일(日)경에 stationary phase에 도달하였다. 2. 배양세포(培養細胞)의 N함량(含量)은 배양후(培養後) 3일(日)경에 높아졌으며, 6일(日)경에는 낮아지고, 다시 9일(日)까지 높아지다가 그 이후(以後)는 서서히 떨어지는 경향을 나타내었다. 3. Cell plating에서 embedding방법(方法)이 가장 높은 micro-callus형성율(形成率)을 보였다. 4. 현탁배양세포(懸濁培養細胞)의 생장(生長)은 LM배지(培地)의 질소량(窒素量)을 1/2로 하고 BAP 0.01, 2,4-D0.1, NAA $1.0mg/{\ell}$ 첨가한 배지(培地)에서 배양(培養) 15일 후에 76.9배(倍)의 생장량(生長量)을 보여 가장 양호(良好)하였고, LM 배지(培地)가 MS나 GD배지(培地)보다 생장(生長)이 좋았으며, auxin만 사용(使用)한 것보다 cytokinin과 혼합하여 배양(培養)하였을 때, 더 좋은 세포생장(細胞生長)을 나타내었다. 5. Single cell 및 small cell aggregates 집단(集團)으로부터의 micro-callus 형성(形成)은 2,4-D를 $1.0mg/{\ell}$ 첨가한 LM 및 MS배지(培地)에서 배양(培養)하였을 때만 형성(形成)되었다.

• BMB Reports
• /
• 제55권2호
• /
• pp.65-71
• /
• 2022

Regenerative medicine is a research field that develops methods to restore damaged cell or tissue function by regeneration, repair or replacement. Stem cells are the raw material of the body that is ultimately used from the point of view of regenerative medicine, and stem cell therapy uses cells themselves or their derivatives to promote responses to diseases and dysfunctions, the ultimate goal of regenerative medicine. Stem cell-derived extracellular vesicles (EVs) are recognized as an attractive source because they can enrich exogenous microRNAs (miRNAs) by targeting pathological recipient cells for disease therapy and can overcome the obstacles faced by current cell therapy agents. However, there are some limitations that need to be addressed before using miRNA-enriched EVs derived from stem cells for multiplexed therapeutic targeting in many diseases. Here, we review various roles on miRNA-based stem cell EVs that can induce effective and stable functional improvement of stem cell-derived EVs. In addition, we introduce and review the implications of several miRNA-enriched EV therapies improved by multiplexed targeting in diseases involving the circulatory system and nervous system. This systemic review may offer potential roles for stem cell-derived therapeutics with multiplexed targeting.

• 한국정보통신학회논문지
• /
• 제13권6호
• /
• pp.1045-1050
• /
• 2009

본 연구에서는 MicroTec을 이용하여 태양전지의 전류-전압 특성곡선을 분석하였다. 전류-전압 특성곡선은 태양전지의 효율을 나타낸다. 전극이 직접 접촉하는 부분에 고농도 도핑을 하고 전극이 없는 부분에 저농도 도핑으로 전면을 처리한다. 도핑 농도를 $10^{14}cm^{-3}$에서 $10^{17}cm^{-3}$까지 변화시켜 도핑 농도에 따른 전류전압특성을 조사하였다. 또한 태양전지의 최대효율을 얻을 수 있는 도핑 농도를 결정하여 이의 전류-전압특성곡선을 비교 분석 하고자한다.

• Design & Manufacturing
• /
• 제11권3호
• /
• pp.51-55
• /
• 2017

Micro fuel cells have high reliability and long usage time. Among them, PEMFC (polymer Electrolyte Membrane Fuel Cell) is suitable as a portable power source because it is easy to fix electrolyte and simple structure. The bipolar plate, a key component of the fuel cell, is produced by cutting. In the case of micro fuel cell separator, burr is very small and the flow channel size in the separator is very small. Therefore, it is difficult to remove burrs in the usual way such as a brushing or ultra-sonic method. Therefore, this study proposed electrolytic polishing process and analyzed the characteristics of each condition by introducing the concept of roughness reduction rate. In addition, the ultrasonic process was added to analyze the effect of ultrasonic addition.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권14호
• /
• pp.5583-5586
• /
• 2014

Helicobacter pylori (H. pylori) infection induces apoptosis in gastric epithelial cells, and this occurrence may link to gastric carcinogenesis. However, the regulatory mechanism of H. pylori-induced apoptosis is not clear. MicroRNA-146a has been implicated as a key regulator of the immune system. This report describes our discovery of molecular mechanisms of microRNA-146a regulation of apoptosis in human gastric cancer cells. We found that overexpression of microRNA-146a by transfecting microRNA-146a mimics could significantly enhance apoptosis, and this upregulation was triggered by COX-2 inhibition. Furthermore, we found that microRNA-146a density was positively correlated with apoptosis rates in H. pylori-positive gastric cancer tissues and intratumoral microRNA-146a density was negatively correlated with lymph node metastasis among H. pylori-positive gastric cancer patients. Understanding the important roles of microRNA-146a in regulating cell apoptosis in H. pylori infected human gastric cancer cells will contribute to the development of microRNA targeted therapy in the future.