• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.282-286
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• 2009

The synthesis and characterization of catalysts supported on multi-walled carbon nanotubes (CNTs). $Pt/Au/TiO_2$ is added to a CNTs(cabon nano tube) carbon support to improve the performance of a direct methanol fuel cell. XRD and SEM showed that uniform anatase $TiO_2$ and Pt/Au particles were about 200 nm and 20${\sim}$25 nm in diameter. The composite catalyst activities were measured by cyclic voltammetry (CV), demonstrating that it is more promising for use in fuel cells.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.587-596
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• 2005

In this paper, we propose an OFDMA/CDM-based cellular system, which accommodates multiple users in frequency-domain and multiplexes user data with frequency-domain spreading. The proposed system utilizes random codes to discriminate cells and adopts the pre-equalization to enhance the performance. For cellular applications, a number of pre-equalization techniques are compared and an efficient power allocation scheme is suggested with a transmit power constraint. Especially, the validity of OFDMA/CDM based cellular system is investigated, by comparing the performance for varying the number of multiplexed data symbols at different locations. Finally the pre/post-equalization is proposed to reduce the performance degradation caused by time delay.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.977-980
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• 2004

본 논문에서는 저가 고효율 태양전지를 제작하기 위하여 p형 다결정 실리콘 기판을 사용하여 수산화 칼륨(KOH)이 포함된 용액에 Saw damage 과정 후 불산이 함유된 용액에 전기화학적 양극산화 과정으로 실리콘 웨이퍼 표면에 요철을 형성하여 다공성 실리콘을 형성 하였다. 본 논문은 전기화학적 에칭방법으로 기존의 진공장비로 제작된 반사방지막의 반사율만큼 감소된 다공성 실리콘 반사방지막을 형성하였다. 전자빔 증착기(e-beam evaporator)로 단층으로 형성된 $TiO_2$의 반사방지막은 400-1000 nm의 파장 범위에서 4.1 %의 평균 반사율을 가졌으며, 양극산화과정으로 형성된 다공성 실리콘은 400-1000 nm의 파장의 범위에서 4.4 %의 평균 반사율을 가졌다. 본 연구는 태양전지의 반사방지막 형성을 기존의 제작 방법보다 간단하고 저렴한 방법으로 접근하여 태양전지의 변환효율을 상승하는데 목적을 두었다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.20-26
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• 2012

The newly introduced model of a STTC-based Distributed Wireless Communication System (DWCS) can provide the capability of joint control of the signals at multiple cells. This paper has considered the virtual cell systems: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on DWCS network. The considered system constructs DVC by using antenna selection method. Also, for multi-user high-rate data transmission, the proposed system introduces multiple antenna technology to get a spatial and temporal diversity gain and exploits space-time trellis codes known as STTC to increase a spectral efficiency.

• BMB Reports
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• v.48 no.8
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• pp.454-460
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• 2015

Naturally occurring reoviruses are live replication-proficient viruses that specifically infect human cancer cells while sparing their normal counterpart. Since the discovery of reoviruses in 1950s, they have shown various degrees of safety and efficacy in pre-clinical or clinical applications for human anti-cancer therapeutics. I have recently discovered that cellular tumor suppressor genes are also important in determining reoviral tropism. Carcinogenesis is a multi-step process involving the accumulation of both oncogene and tumor suppressor gene abnormalities. Reoviruses can exploit abnormal cellular tumor suppressor signaling for their oncolytic specificity and efficacy. Many tumor suppressor genes such as p53, ataxia telangiectasia mutated (ATM), and retinoblastoma associated (RB) are known to play important roles in genomic fidelity/maintenance. Thus, a tumor suppressor gene abnormality could affect host genomic integrity and likely disrupt intact antiviral networks due to the accumulation of genetic defects which in turn could result in oncolytic reovirus susceptibility. This review outlines the discovery of oncolytic reovirus strains, recent progresses in elucidating the molecular connection between oncogene/tumor suppressor gene abnormalities and reoviral oncotropism, and their clinical implications. Future directions in the utility of reovirus virotherapy is also proposed in this review. [BMB Reports 2015; 48(8): 454-460]

• BMB Reports
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• v.51 no.2
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• pp.57-58
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• 2018

An accurate diagnostic marker for detecting early-stage hepatocellular carcinoma (eHCC) is clinically important, since early detection of HCC remarkably improves patient survival. From the integrative analysis of the transcriptome and clinicopathologic data of human multi-stage HCC tissues, we were able to identify barrier-to-autointegration factor 1 (BANF1), procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3 (PLOD3) and splicing factor 3b subunit 4 (SF3B4) as early HCC biomarkers which could be detected in precancerous lesions of HCC, with superior capabilities to diagnose eHCC compared to the currently popular HCC diagnostic biomarkers: GPC3, GS, and HSP70. We then showed that SF3B4 knockdown caused G1/S cell cycle arrest by recovering $p27^{kip1}$ and simultaneously suppressing cyclins, and CDKs in liver cancer cells. Notably, we demonstrated that aberrant SF3B4 overexpression altered the progress of splicing progress of the tumor suppressor gene, kruppel like factor 4 (KLF4), and resulted in non-functional skipped exon transcripts. This contributes to liver tumorigenesis via transcriptional inactivation of $p27^{kip1}$ and simultaneous activation of Slug genes. Our results suggest that SF3B4 indicates early-stage HCC in precancerous lesions, and also functions as an early-stage driver in the development of liver cancer.

• Molecules and Cells
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• v.26 no.6
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• pp.554-557
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• 2008

Double-stranded RNA (dsRNA) induces gene silencing in a sequence-specific manner by a process known as RNA interference (RNAi). The RNA-induced silencing complex (RISC) is a multi-subunit ribonucleoprotein complex that plays a key role in RNAi. VIG (Vasa intronic gene) has been identified as a component of Drosophila RISC; however, the role VIG plays in regulating RNAi is poorly understood. Here, we examined the spatial and temporal expression patterns of VIG-1, the C. elegans ortholog of Drosophila VIG, using a vig-1::gfp fusion construct. This construct contains the 908-bp region immediately upstream of vig-1 gene translation initiation site. Analysis by confocal microscopy demonstrated GFP-VIG-1 expression in a number of tissues including the pharynx, body wall muscle, hypodermis, intestine, reproductive system, and nervous system at the larval and adult stages. Furthermore, western blot analysis showed that VIG-1 is present in each developmental stage examined. To investigate regulatory sequences for vig-1 gene expression, we generated constructs containing deletions in the upstream region. It was determined that the GFP expression pattern of a deletion construct (${\Delta}-908$ to -597) was generally similar to that of the non-deletion construct. In contrast, removal of a larger segment (${\Delta}-908$ to -191) resulted in the loss of GFP expression in most cell types. Collectively, these results indicate that the 406-bp upstream region (-596 to -191) contains essential regulatory sequences required for VIG-1 expression.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.1-13
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• 1998

The next generation of wireless network will be problably developed as a mobile communications which will support ATM-based multiMedium traffic. We need to develop an dffective MAC protocol in order to support multimedia traffic having variety of QoS characteristics on wireless neteworks. In this paper, we propose a MAC protocol a MAC protocol where mobile terminals having cells to transmit, request slots to base station through requested slot then the base station analyze parameters from mobile and allocate slots to mobile according to priority. The multimedia slot allocation(MSA) protocol divides multimedias applications into real-time/ variant and non real-time services. Entire slots of the frameare partitioned proportionallyby sizeof bandwidth according to types of services, so that related services can use allocated-slots in priority. The proposed algorithm guarantees real time operation since real-time service share slots allocated for non real-real services. The algorithm whih divides slots of the frame is called as an Algorithm A, otherwise as an Algorithm B. The simulation compares by average delay time and cell loss probability between Algorithm and Algorithm B by increasing number of mobile terminal using the proposed MAC protocol. the simulation result for real-time services shows that average delay time and cell loss probability of Algorithm A is better than those of Algorithm B.

• 대한공업교육학회지
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• v.33 no.2
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• pp.300-311
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• 2008

This study investigates the natural convection of air(Pr=0.7) between two walls having a small- wave- number sinusoidal temperature distributions with a phase difference. The wave number and the phase difference of wall temperatures are k=0.5 and ㄱ/2, respectively. In the conduction-dominated regime at small Rayleigh number, two slightly inclined cells are formed over one wave length. At higher Rayleigh number, however, multicellular convection occurs in thermally unstable region. A spatial symmetry is intermittently broken in the transient period at the Rayleigh number near the critical value. The steady-state flows always satisfy the spatial symmetry. A steep increase of Nusselt number occurs near the Rayleigh number at which transition of flow pattern occurs.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6343-6347
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• 2014

Multi-target drug design, in which drugs are designed as single molecules to simultaneously modulate multiple physiological targets, is an important strategy in the field of drug discovery. QT-011, a tamibarotene-furoxan derivative, was here prepared and proposed to exert synergistic effects on antileukemia by releasing nitric oxide and tamibarotene. Compared with tamibarotene itself, QT-011 displayed stronger antiproliferative effects on U937 and HL-60 cells and was more effective evaluated in a nude mice U937 xenograft model in vivo. In addition, QT-011 could release nitric oxide which might contribute to the antiproliferative activity. Autodocking assays showed that QT-011 fits well with the hydrophobic pocket of retinoic acid receptors. Taken together, these results suggest that QT-011 might be a highly effective derivative of tamibarotene and a potential candidate compound as antileukemia agent.