• Biomolecules & Therapeutics
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• 제20권3호
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• pp.299-305
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• 2012

Endochondral bone formation is the process by which mesenchymal cells condense to become chondrocytes, which ultimately form new bone. The process of chondrogenic differentiation and hypertrophy is critical for bone formation and as such is regulated by many factors. In this study, we aimed to indentify novel factors that regulate chondrogenesis. We investigated the possible role of isopsoralen in induction of chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Isopsoralen treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. Further, ATDC5 cells treated with isopsoralen were stained more intensely with Alcian blue than control cells, suggesting that isopsoralen increases the synthesis of matrix proteoglycans. Similarly, isopsoralen markedly induced the activation of alkaline phosphatase activity compared with control cells. Isopsoralen enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, OCN, Smad4 and Sox9 in a time-dependent manner. Furthermore, isopsoralen induced the activation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase, but not that of c-jun N-terminal kinase (JNK). Isopsoralen significantly enhanced the protein expression of BMP-2 in a time-dependent manner. PD98059 and SB 203580, inhibitors of ERK and p38 MAPK, respectively, decreased the number of stained cells treated with isopsoralen. Taken together, these results suggest that isopsoralen mediates a chondromodulating effect by BMP-2 or MAPK signaling pathways, and is therefore a possible therapeutic agent for bone growth disorders.

• 방송공학회논문지
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• 제18권6호
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• pp.859-871
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• 2013

본 논문에서는 스테레오 영상에서 얻은 다양한 특징들과 차폐영역에 대한 정보들을 활용하여 그리드 메쉬(grid-mesh) 기반의 영상워핑 기법을 통해 다시점 영상을 생성하는 방법을 제안한다. 제안된 기법에서는 먼저 주어진 스테레오 영상에서 영상 특징 지도(image saliency map), 직선 성분(line segments) 그리고 변이 특징 지도(disparity saliency map)를 추출하고, 추출된 특징들에 대하여 품질을 향상시키는 과정을 거친다. 이 과정은 두 가지 단계로 나뉘는데, 먼저 차폐영역에 대한 정보를 활용하여 객체의 경계 부근에서 추출된 변이 특징 지도의 신뢰도를 향상시킨다. 다음으로 스테레오 영상에서의 시간적 일관성(temporal consistency)에 대한 정보를 활용하여 추출된 영상 특징들의 시간적 일관성을 높인다. 이렇게 품질이 향상된 특징 성분들을 활용하여 그리드 메쉬 기반의 영상 워핑 기법을 통해 다시점 영상을 생성한다. 실험 결과를 통해 제안된 기법으로 생성한 다시점 영상의 주관적 화질 측면에서 기존의 다시점 영상 생성 기법들보다 우수한 것을 확인할 수 있었다.

• Journal of Korean Neurosurgical Society
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• 제64권5호
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• pp.705-715
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• 2021

Objective : Through our previous clinical trials, the demonstrated therapeutic effects of MSC in chronic spinal cord injury (SCI) were found to be not sufficient. Therefore, the need to develop stem cell agent with enhanced efficacy is increased. We transplanted enhanced Wnt3-asecreting human mesenchymal stem cells (hMSC) into injured spines at 6 weeks after SCI to improve axonal regeneration in a rat model of chronic SCI. We hypothesized that enhanced Wnt3a protein expression could augment neuro-regeneration after SCI. Methods : Thirty-six Sprague-Dawley rats were injured using an Infinite Horizon (IH) impactor at the T9-10 vertebrae and separated into five groups : 1) phosphate-buffered saline injection (injury only group, n=7); 2) hMSC transplantation (MSC, n=7); 3) hMSC transfected with pLenti vector (without Wnt3a gene) transplantation (pLenti-MSC, n=7); 4) hMSC transfected with Wnt3a gene transplantation (Wnt3a-MSC, n=7); and 5) hMSC transfected with enhanced Wnt3a gene (1.7 fold Wnt3a mRNA expression) transplantation (1.7 Wnt3a-MSC, n=8). Six weeks after SCI, each 5×10⁵ cells/15 µL at 2 points were injected using stereotactic and microsyringe pump. To evaluate functional recovery from SCI, rats underwent Basso-Beattie-Bresnahan (BBB) locomotor test on the first, second, and third days post-injury and then weekly for 14 weeks. Axonal regeneration was assessed using growth-associated protein 43 (GAP43), microtubule-associated protein 2 (MAP2), and neurofilament (NF) immunostaining. Results : Fourteen weeks after injury (8 weeks after transplantation), BBB score of the 1.7 Wnt3a-MSC group (15.0±0.28) was significantly higher than that of the injury only (10.0±0.48), MSC (12.57±0.48), pLenti-MSC (12.42±0.48), and Wnt3a-MSC (13.71±0.61) groups (p<0.05). Immunostaining revealed increased expression of axonal regeneration markers GAP43, MAP2, and NF in the Wnt3a-MSC and 1.7 Wnt3a-MSC groups. Conclusion : Our results showed that enhanced gene expression of Wnt3a in hMSC can potentiate axonal regeneration and improve functional recovery in a rat model of chronic SCI.

• ETRI Journal
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• 제36권5호
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• pp.752-760
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• 2014

This paper proposes a conditional replenishment algorithm (CRA) to improve the visual quality (where spatial resolutions of the left and right views are mismatched) of a hybrid stereoscopic 3DTV that is based on the ATSC-M/H standard. So as to generate an enhanced view, the CRA is to choose the better substitute among a disparity-compensated view with high quality and a simply interpolated view. The CRA generates a disparity map that includes modes and disparity vectors as additional information. It also employs a quad-tree structure with variable block size by considering the spatial correlation of disparity vectors. In addition, it takes advantage of the disparity map used in a previous frame to keep the amount of additional information as small as possible. The simulation results show that the proposed CRA can successfully improve the peak signal-to-noise ratio of a poor-quality view and consequently have a positive effect on the subjective quality of the resulting 3D view.

• Bioinformatics and Biosystems
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• 제1권1호
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• pp.51-60
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• 2006

The paradigm in biology is currently changing from that of conducting hypothesis-driven individual experiments to that of utilizing the results of a massive data analysis with appropriate computational tools. We present LayMap, an implemented visualization system that helps the user to deal with a high volume of the biomedical literature such as MEDLINE, through the layered maps that are constructed on the results of an information extraction system. LayMap also utilizes filtering and granularity for an enhanced view of the results. Since a biomedical information extraction system gives rise to a focused and effective way of slicing up the data space, the combined use of LayMap with such an information extraction system can help the user to navigate the data space in a speedy and guided manner. As a case study, we have applied the system to datasets of journal abstracts on 'MAPK pathway' and 'bufalin' from MEDLINE. With the proposed visualization, we have successfully rediscovered pathway maps of a reasonable quality for ERK, p38 and JNK. Furthermore, with respect to bufalin, we were able to identify the potentially interesting relation between the Chinese medicine Chan su and apoptosis with a high level of detail.

• 인터넷정보학회논문지
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• 제11권2호
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• pp.173-184
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• 2010

유비쿼터스 네트워크 기술이 발전하면서 모바일 단말기를 이용한 인터넷 사용은 휴대성과 편의성뿐만 아니라 시간과 장소에 구애 받지 않기 때문에 점점 증가하고 있다. 그러나 모바일 단말기의 다양한 기종과 많은 마크업 언어의 종류 등의 원인으로 모바일 컨텐츠 제작은 많은 어려움을 겪고 있다. 본 논문에서는 편집한 모바일 웹 페이지를 모바일 단말기에서 서비스할때 편집한 화면과 동일한 형태로 서비스하기 위하여 이미지 맵 방법을 제안하였다. 제안된 이미지 맵 방법을 이용한 모바일 웹 서비스 방법은 웹 페이지를 구성하고 있는 여러 개의 객체들을 하나의 이미지로 캡쳐해서 서비스하는 방법이다. 제안된 방법을 이용한 모바일 단말기는 몇 개의 객체들로 페이지를 재구성 할 때 표현이 더 쉽고 편집과 동일한 단말기 서비스 화면을 얻을 수 있었다.

• Genomics & Informatics
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• 제6권2호
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• pp.57-63
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• 2008

The Korean HapMap Project has been carried out for the last 5 years since it started in June, 2003. The project generated data for a sum of 1,764,000 Korean SNPs and formally registered the data to the dbSNP of NCBI (The dbSNP website. 2008). We have developed a series of software programs for association studies as well as for the comparison and analysis of Korean HapMap data with four other populations (CEPH, Yoruba, Han Chinese, and Japanese populations). The KHapmap Browser was developed and integrated to provide haplotype retrieval and comparative study tools of human ethnicities for comprehensive disease association studies (http://www.khapmap.org). On that basis, GBrowse was adopted in the KHapmap Browser for inherent Korean genetic data, and a provision of extended services was pledged with the distributed sequence annotation system (DAS). The dynamic linking service of the KHapmap Browser to other tools in our intranetwork environment provides many enhanced functions over GBrowse without DAS. KHapmap Browser is expected to be an invaluable tool for the study of Korean and international Hapmap data.

• 대기
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• 제21권3호
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• pp.221-228
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• 2011

The nonlinear characteristics of summer monsoon intraseasonal oscillation (ISO) in precipitation, which is manifested as fluctuations in convection and circulation, is one of the major difficulty on the prediction of East Asian summer monsoon (EASM). The present study aims to identify the spatial distribution and time evolution of nonlinear phases of monsoon ISO. In order to classify the different phases of monsoon ISO, Self-Organizing Map(SOM) known as a nonlinear pattern recognition technique is used. SOM has a great attractiveness detecting self-similarity among data elements by grouping and clustering such self-similar components. The four important patterns are demonstrated as Meiyu-Baiu, Changma, post-Changma, and dry-spell modes. It is found that SOM well captured the formation of East Asian monsoon trough during early summer and its northward migration together with enhanced convection over subtropical western Pacific and regionally intensive precipitation including Meiyu, Changma and Baiu. The classification of fundamental large scale spatial pattern and evolutionary history of nonlinear phases of monsoon ISO provides the source of predictability for extended-range forecast of summer precipitation.

• Wind and Structures
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• 제38권6호
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• pp.445-459
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• 2024

To model the aeroelasticity in vortex-induced vibrations (VIV) of slender tubular towers, this paper presents an approach where the aerodynamic damping distribution along the height of the structure is calculated not only as a function of the normalized lateral oscillation but also considering the local incoming wind velocity ratio to the critical velocity (velocity ratio). The three-dimensionality of aerodynamic damping depending on the tower's displacement and the velocity ratio has been observed in recent studies. A contour map model of aerodynamic damping is generated based on the forced vibration tests. A sectional calculation procedure based on the spectral method is developed by defining the aerodynamic damping locally at each increment of height. The proposed contour map model of aerodynamic damping and the sectional calculation procedure are validated with full-scale measurement data sets of a rotorless wind turbine tower, where good agreement between the prediction and measured values is obtained. The prediction of cross-wind response of the wind turbine tower is performed over a range of wind speeds which allows the estimation of resulting fatigue damage. The proposed model gives more realistic prediction in comparison to the approach included in current standards.

• 대한의생명과학회지
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• 제15권2호
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• pp.141-146
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• 2009

Paclitaxel, an antimicrotubule agent, binds to beta-tubulin in the microtubule and stabilizes the polymer, thereby repressing dynamic instability. Here, we have demonstrated that microtubule cytoskeletal architecture involved in regulation of the COX-2 expression in chondrocyte treated with paclitaxel. Paclitaxel enhanced COX-2 expression and prostaglandin E2 production, as indicated by the Western blot analysis, reverse transcriptase PCR(RT-PCR) and immunofluorescence staining, and $PGE_2$ assay, respectively. In our previous data have shown that paclitaxel treatment stimulated activation of ERK-1/2 and p38 kinase(Im et al., 2009). SB203580, an inhibitor of p38 kinase, blocked the induction of COX-2 expression by paclitaxel. Also PD98059, an inhibitor of ERK-1/2 kinase was blocked the induced COX-2 expression. These results indicate that activation of ERK-1/2 and p38 kinase is required for COX-2 expression induced by paclitaxel in rabbit articular chondrocytes.