• Carbon letters
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• 제15권1호
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• pp.1-14
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• 2014

Carbon nanofibers (CNFs) with diameters in the submicron and nanometer range exhibit high specific surface area, hierarchically porous structure, flexibility, and super strength which allow them to be used in the electrode materials of energy storage devices, and as hybrid-type filler in carbon fiber reinforced plastics and bone tissue scaffold. Unlike catalytic synthesis and other methods, electrospinning of various polymeric precursors followed by stabilization and carbonization has become a straightforward and convenient way to fabricate continuous CNFs. This paper is a comprehensive and brief review on the latest advances made in the development of electrospun CNFs with major focus on the promising applications accomplished by appropriately regulating the microstructural, mechanical, and electrical properties of as-spun CNFs. Additionally, the article describes the various strategies to make a variety of carbon CNFs for energy conversion and storage, catalysis, sensor, adsorption/separation, and biomedical applications. It is envisioned that electrospun CNFs will be the key materials of green science and technology through close collaborations with carbon fibers and carbon nanotubes.

• 마이크로전자및패키징학회지
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• 제20권3호
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• pp.1-6
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• 2013

TSV는 그동안 3D IC 적층을 하는데 핵심 기술로 많이 연구되어 왔고, RC delay를 줄여 소자의 성능을 향상시키고, 전체 시스템 사이즈를 줄일 수 있는 기술로 각광을 받아왔다. 최근에는 TSV를 전기적 연결이 아닌 소자의 열관리를 위한 구조로 연구되고 있다. TSV를 이용한 liquid cooling 시스템 개발은 TSV 제조, TSV 디자인 (aspect ratio, size, distribution), 배선 밀도, microchannel 제조, sealing, 그리고 micropump 제조까지 풀어야 할 과제가 아직 많이 남아있다. 그러나 TSV를 이용한 liquid cooling 시스템은 열관리뿐 아니라 신호 대기시간(latency), 대역폭(bandwidth), 전력 소비(power consumption), 등에 크게 영향을 미치기 때문에 3D IC 적층 기술의 장점을 최대로 이용한 차세대 cooling 시스템으로 지속적인 개발이 필요하다.

• 융합보안논문지
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• 제13권1호
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• pp.51-57
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• 2013

공개키 방식으로 가장 널리 사용되는 알고리즘은 RSA이다. 본 연구는 SSL 통신 및 RSA를 이용한 사용자 인증을 통해 결제 등의 과정에서 사용자의 소중한 정보를 안전하게 보호할 수 있는 안전한 사이버거래 구축방안을 제시한다. SSL은 전자서명 기술을 기반으로 한 암호화 프로토콜이며 이 기술이 적용된 전자문서는 별도의 암호화 과정을 거쳐 상대방에게 전달되므로 정보 송신자(웹브라우저에 정보를 입력하는 사용자)와 정보 수신자(해당 사이트의 웹서버 관리자) 외에는 그 내용을 해독할 수 없다. 따라서 전자문서가 전송되는 도중에 해커가 Sniffing을 시도한다고 해도 정보가 암호화 되어 있기 때문에 그 내용을 절대로 파악할 수 없다. 본 연구는 인터넷 쇼핑몰에서의 사용자 인증'과 'SSL 통신'을 이용한 안전한 쇼핑몰 구축을 목표로 방법론을 제시한다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.487-498
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• 2016

Leptin, an adipokine predominantly produced from adipose tissue, is well known to induce tumor growth. However, underlying molecular mechanisms are not established yet. While p53 has long been well recognized as a potent tumor suppressor gene, accumulating evidence has also indicated its potential role in growth and survival of cancer cells depending on experimental environments. In the present study, we examined if p53 signaling is implicated in leptin-induced growth of cancer cells. Herein, we demonstrated that leptin treatment significantly increased p53 protein expression in both hepatic (HepG2) and breast (MCF-7) cancer cells without significant effect on mRNA expression. Enhanced p53 expression by leptin was mediated via modulation of ubiquitination, in particular ubiquitin specific protease 2 (USP2)-dependent manner. Furthermore, gene silencing of p53 by small interfering RNA (siRNA) suppressed leptin-induced growth of hepatic and breast cancer cells, indicating the role of p53 signaling in tumor growth by leptin. In addition, we also showed that knockdown of p53 restored suppression of caspase-3 activity by leptin through modulating Bax expression and prevented leptin-induced cell cycle progression, implying the involvement of p53 signaling in the regulation of both apoptosis and cell cycle progression in cancer cells treated with leptin. Taken together, the results in the present study demonstrated the potential role of p53 signaling in leptin-induced tumor growth.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.103-111
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• 2014

A1E is an extract from traditional Asian medicinal plants that has therapeutic activities against cancers, metabolic disease, and other intractable conditions. However, its mechanism of action on cervical cancer has not been studied. In order to ascertain if A1E would have pronounced anti-cervical cancer effect, cervical cancer cells were incubated with A1E and apoptosis was detected by nuclear morphological changes, annexin V-FITC/PI staining, cell cycle analysis, western blotting, Reverse-transcription polymerase chain reaction, and measurement of mitochondrial membrane potential. Expression of human papiloma virus E6 and E7 oncogenes was down-regulated in A1E-treated cervical cancer cells, while p53 and retinoblastoma protein levels were enhanced. A1E also perturbed cell cycle progression at sub-G1 and altered cell cycle regulatory factors in SiHa cervical cancer cells. A1E activated apoptotic intrinsic pathway markers such as caspase-9, caspase-3 and poly ADP-ribose polymerase, and down-regulated expression of Bcl-2 and Bcl-xl. A1E induced mitochondrial membrane potential collapse and cytochrome c release, and inhibited phosphatidylinositol 3-kinase (PI3K)/Akt, key factors involved in cell survival signaling. Taken all these results, A1E induced apoptosis via activation of the intrinsic pathway and inhibition of the PI3K/Akt survival-signaling pathway in SiHa cervical cancer cells. In conclusion, A1E exerts anti-proliferative action growth inhibition on cervical cancer cells through apoptosis which demonstrates its anti-cervical cancer properties.

• Molecules and Cells
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• 제45권12호
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• pp.963-975
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• 2022

Exogenous polyamines are able to induce life span and improve glucose homeostasis and insulin sensitivity. However, the effects of exogenous polyamines on adipocyte differentiation and which polyamine transporters mediate them have not been elucidated yet. Here, we identified for the first time that exogenous polyamines can clearly stimulate adipocyte differentiation through polyamine transporters, solute carrier family 3 member A2 (SLC3A2) and SLC7A1. Exogenous polyamines markedly promote 3T3-L1 adipocyte differentiation by increasing the intracellular lipid accumulation and the expression of both adipogenic and lipogenic genes in a concentration-dependent manner. In particular, exogenous putrescine mainly regulates adipocyte differentiation in the early and intermediate stages. Moreover, we have assessed the expression of polyamine transporter genes in 3T3-L1 preadipocytes and adipocytes. Interestingly, the putrescine-induced adipocyte differentiation was found to be significantly suppressed in response to a treatment with a polyamine transporter inhibitor (AMXT-1501). Furthermore, knockdown experiments using siRNA that specifically targeted SLC3A2 or SLC7A2, revealed that both SLC3A2 and SLC7A2 act as important transporters in the cellular importing of exogenous putrescine. Thus, the exogenous putrescine entering the adipocytes via cellular transporters is involved in adipogenesis through a modulation of both the mitotic clonal expansion and the expression of master transcription factors. Taken together, these results suggest that exogenous polyamines (such as putrescine) entering the adipocytes through polyamine transporters, can stimulate adipogenesis.

• 자원환경지질
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• 제53권1호
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• pp.1-9
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• 2020

이산화탄소 고정화 및 탄산화 반응에는 칼슘(Ca)과 마그네슘(Mg)과 같은 알칼리토류 금속을 함유하고 있는 사문석(serpentine, Mg₃Si₂O₅(OH)₄) 규회석(wollastonite, CaSiO₃), 감람석(olivine, Mg₂SiO₄)과 같은 칼슘/마그네슘 실리케이트 광물(Ca/Mg-silicate mineral)들이 주로 이용되어 왔다. 특히 사문석은 탄산화가 가능한 자연물질 중 자연계 내에 풍부한 매장량을 갖고 있으며, 우수한 반응성 때문에 광물탄산화에 가장 적절한 출발물질로 인식되어 있다. 따라서 본 연구는 사문석을 출발물질로 사용하여 산성 용액 내에서 이산화탄소의 압력이 탄산화 효율에 미치는 영향력을 확인하고자 하였다. 탄산화 실험 조건은 황산용액 0.3~1 M, 반응온도 100℃ 및 150℃ 그리고 이산화탄소의 부분압력 0~3 MPa이며, 탄산화법은 수정된 직접탄산화법(modified direct method)으로 실시하였다. 또한 탄산화 효율을 높이고자 liquid pump로 NaOH 용액을 주입하여 pH를 13으로 조절하였다. 탄산화율은 황산의 농도 및 반응온도에 비례하여 증가하였으며, 3 MPa의 이화탄소를 주입한 조건에서의 탄산화율이 이산화탄소를 첨가하지 않은 조건의 탄산화율보다 높았다. 반응결과 황산용액 1 M과 이산화탄소 부분압 3 MPa, 반응온도 150℃에서 용출 및 탄산화 실험 후 약 85%의 상당히 높은 탄산화율이 분석되었다. 따라서 산성용액에서 이산화탄소의 압력이 사문석 내의 Mg 용출에 영향을 미치는 것으로 확인되었다. Mg의 용해속도는 Si의 용해속도보다 높아 반응 후 사문석의 Mg : Si의 비가 약 1.5에서 0.1미만으로 급속하게 감소하여, 사문석의 구조 내에 불완전한 Si 사면체 층 골격구조(Mg-depleted skeletal phase)가 분석되었다.

• BMB Reports
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• 제50권12호
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• pp.628-633
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• 2017

Gastrin-releasing peptide (GRP) has been reported to be implicated in the pathogenesis of inflammatory disorders. The migration and proliferation of vascular smooth muscle cells (VSMCs) are key components of vascular inflammation that leads to the development of atherosclerosis. The present study aimed to investigate the molecular effect of GRP on VSMC proliferation and migration. We report that GRP significantly enhanced the proliferation and migration of rat VSMCs. GRP increased mRNA and protein expression of matrix metalloproteinase-2 and -9 (MMP-2/9) in VSMCs. The induction of MMP-2/9 by GRP was regulated by the activation of the signal transducer and activator of transcription-3 (STAT3). In addition, STAT3-knockdown of VSMCs by siRNA or blockade of the GRP receptor inhibited GRP-induced migration of VSMCs. Taken together, our findings indicate that GRP promotes the migration of VSMCs through upregulation of MMP-2/9 via STAT3 activation.

• Journal of Chest Surgery
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• 제42권3호
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• pp.396-400
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• 2009

다빈치 로봇수술은 현재 다양한 외과영역에서 시행되고 있으나 폐, 식도 외과영역에서는 아직까지 널리 이용되지 않고 있다. 본원에서는 74세 남자환자가 딸꾹질과 연하곤란을 주소로 내원하여 시행한 검사에서 식도암으로 진단되어 da Vinci 로봇을 이용하여 식도절제술을 시행한 후, 복강경으로 위장튜브를 만들어 흉골하 통로를 통해 경부에서 위장-식도 단단 문합을 시행하였다. 환자는 수술 후 특별한 합병증 없이 완쾌 퇴원하였다. 향후 다빈치로봇을 이용한 최소 침습수술이 식도암을 비롯한 폐, 식도외과 영역에의 활용에 있어서 좋은 결과가 기대되므로 보고하는 바이다.

• The Korean Journal of Physiology and Pharmacology
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• 제17권4호
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• pp.307-314
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• 2013

Connective tissue growth factor (CTGF) is a potent pro-fibrotic factor, which is implicated in fibrosis through extracellular matrix (ECM) induction in diabetic cardiovascular complications. It is an important downstream mediator in the fibrotic action of transforming growth factor ${\beta}$ ($TGF{\beta}$) and is potentially induced by hyperglycemia in human vascular smooth muscle cells (VSMCs). Therefore, the goal of this study is to identify the signaling pathways of CTGF effects on ECM accumulation and cell proliferation in VSMCs under hyperglycemia. We found that high glucose stimulated the levels of CTGF mRNA and protein and followed by VSMC proliferation and ECM components accumulation such as collagen type 1, collagen type 3 and fibronectin. By depleting endogenous CTGF we showed that CTGF is indispensable for the cell proliferation and ECM components accumulation in high glucose-stimulated VSMCs. In addition, pretreatment with the MEK1/2 specific inhibitors, PD98059 or U0126 potently inhibited the CTGF production and ECM components accumulation in high glucose-stimulated VSMCs. Furthermore, knockdown with ERK1/2 MAPK siRNA resulted in significantly down regulated of CTGF production, ECM components accumulation and cell proliferation in high glucose-stimulated VSMCs. Finally, ERK1/2 signaling regulated Egr-1 protein expression and treatment with recombinant CTGF reversed the Egr-1 expression in high glucose-induced VSMCs. It is conceivable that ERK1/2 MAPK signaling pathway plays an important role in regulating CTGF expression and suggests that blockade of CTGF through ERK1/2 MAPK signaling may be beneficial for therapeutic target of diabetic cardiovascular complication such as atherosclerosis.