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Kwon M.J.,Kyungpook National University | Shin Y.K.,Seoul National University | Shin Y.K.,Advanced Institutes of Convergence Technology
International Journal of Molecular Sciences | Year: 2013

Cancer stem cells or tumor-initiating cells (CSC/TICs), which can undergo self-renewal and differentiation, are thought to play critical roles in tumorigenesis, therapy resistance, tumor recurrence and metastasis. Tumor recurrence and chemoresistance are major causes of poor survival rates of ovarian cancer patients, which may be due in part to the existence of CSC/TICs. Therefore, elucidating the molecular mechanisms responsible for the ovarian CSC/TICs is required to develop a cure for this malignancy. Recent studies have indicated that the properties of CSC/TICs can be regulated by microRNAs, genes and signaling pathways which also function in normal stem cells. Moreover, emerging evidence suggests that the tumor microenvironments surrounding CSC/TICs are crucial for the maintenance of these cells. Similarly, efforts are now being made to unravel the mechanism involved in the regulation of ovarian CSC/TICs, although much work is still needed. This review considers recent advances in identifying the genes and pathways involved in the regulation of ovarian CSC/TICs. Furthermore, current approaches targeting ovarian CSC/TICs are described. Targeting both CSC/TICs and bulk tumor cells is suggested as a more effective approach to eliminating ovarian tumors. Better understanding of the regulation of ovarian CSC/TICs might facilitate the development of improved therapeutic strategies for recurrent ovarian cancer. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Jeong H.M.,Seoul National University | Kwon M.J.,Kyungpook National University | Shin Y.K.,Seoul National University | Shin Y.K.,Advanced Institutes of Convergence Technology
Frontiers in Oncology | Year: 2014

Like other cancers, most gynecologic cancers are caused by aberrant expression of cancer-related genes. Epigenetics is one of the most important gene expression mechanisms, which contribute to cancer development and progression by regulating cancer-related genes. Since the discovery of differential gene expression patterns in cancer cells when compared with normal cells, extensive efforts have been made to explore the origins of abnormal gene expression in cancer. Epigenetics, the study of inheritable changes in gene expression that do not alter DNA sequence is a key area of this research. DNA methylation and histone modification are well-known epigenetic mechanisms, while microRNAs and alternative splicing have recently been identified as important regulators of epigenetic mechanisms. These mechanisms not only affect specific target gene expression but also regulate the functioning of other epigenetic mechanisms. Moreover, these diverse epigenetic regulations occur simultaneously. Epigenetic regulation of gene expression is extraordinarily complicated and all epigenetic mechanisms to be studied at once to determine the exact gene regulation mechanisms. Traditionally, the contribution of epigenetics to cancer is thought to be mediated through the inactivation of tumor suppressor genes expression. But recently, it is arising that some oncogenes or cancer-promoting genes (CPGs) are overexpressed in diverse type of cancers through epigenetic derepression mechanism, such as DNA and histone demethylation. Epigenetic derepression arises from diverse epigenetic changes, and all of these mechanisms actively interact with each other to increase oncogenes or CPGs expression in cancer cell. Oncogenes or CPGs overexpressed through epigenetic derepression can initiate cancer development, and accumulation of these abnormal epigenetic changes makes cancer more aggressive and treatment resistance. This review discusses epigenetic mechanisms involved in the overexpression of oncogenes or CPGs via epigenetic derepression in gynecologic cancers. Therefore, improved understanding of these epigenetic mechanisms will provide new targets for gynecologic cancer treatment. © 2014 Jeong, Kwon and Shin.

Jang B.,Korea Advanced Institute of Science and Technology | Park M.,Seoul National University | Chae O.B.,Seoul National University | Park S.,Seoul National University | And 6 more authors.
Journal of the American Chemical Society | Year: 2012

Extensive applications of rechargeable lithium-ion batteries (LIBs) to various portable electronic devices and hybrid electric vehicles result in the increasing demand for the development of electrode materials with improved electrochemical performance including high energy, power density, and excellent cyclability, while maintaining low production cost. Here, we present a direct synthesis of ferrite/carbon hybrid nanosheets for high performance lithium-ion battery anodes. Uniform-sized ferrite nanocrystals and carbon materials were synthesized simultaneously through a single heating procedure using metal-oleate complex as the precursors for both ferrite and carbon. 2-D nanostructures were obtained by using sodium sulfate salt powder as a sacrificial template. The 2-D ferrite/carbon nanocomposites exhibited excellent cycling stability and rate performance derived from 2-D nanostructural characteristics. The synthetic procedure is simple, inexpensive, and scalable for mass production, and the highly ordered 2-D structure of these nanocomposites has great potential for many future applications. © 2012 American Chemical Society.

Kwon M.J.,Advanced Institutes of Convergence Technology | Shin Y.K.,Seoul National University
International Journal of Molecular Sciences | Year: 2011

The involvement of epigenetic aberrations in the development and progression of tumors is now well established. However, most studies have focused on the epigenetic inactivation of tumor suppressor genes during tumorigenesis and little is known about the epigenetic activation of cancer-associated genes, except for the DNA hypomethylation of some genes. Recently, we reported that the overexpression of cancer-promoting genes in ovarian cancer is associated with the loss of repressive histone modifications. This discovery suggested that epigenetic derepression may contribute to ovarian tumorigenesis by constituting a possible mechanism for the overexpression of oncogenes or cancer-promoting genes in tumors. The emerging importance of epigenetic aberrations in tumor initiation and in the regulation of cancer-initiating cells, suggests that epigenetically regulated genes may be promising therapeutic targets and biomarkers. Given that the current challenges in ovarian cancer include the identification of biomarkers for early cancer detection and the discovery of novel therapeutic targets for patients with recurrent malignancies undergoing chemotherapy, understanding the epigenetic changes that occur in ovarian cancer is crucial. This review looks at epigenetic mechanisms involved in the regulation of cancer-associated genes, including the contribution of epigenetic derepression to the activation of cancer-associated genes in ovarian cancer. In addition, possible epigenetic therapies targeting epigenetically dysregulated genes are discussed. A better understanding of the epigenetic changes in ovarian cancer will contribute to the improvement of patient outcomes. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Park J.,Advanced Institutes of Convergence Technology | Jeong H.J.,Seoul National University | Yoo Y.D.,Seoul National University | Yoon E.Y.,Advanced Institutes of Convergence Technology
Harmful Algae | Year: 2013

We investigated the outbreaks of red tides dominated by dinoflagellates in the coastal waters of Korea from 1981 to 2009. During the study period, 693 mixotrophic dinoflagellate red-tide events occurred. Of these, 36.8% were Cochlodinium polykrikoides red tides, with Akashiwo sanguinea, Ceratium furca, and Prorocentrum minimum also frequently forming red tides. Eighty-five percent of mixotrophic dinoflagellate red tides in Korean waters occurred from June to September, in the high water-temperature season. The monthly frequency of outbreaks of mixotrophic dinoflagellate red tides increased from twice in January-March to 228 times in August, but it decreased to 2-9 times in November and December. Eighty-six percent of the outbreak events were recorded in southern coastal waters, 12% in eastern coastal waters, and only 2% in western coastal waters of Korea. There were wide temperature and salinity ranges during red tides associated with A. sanguinea, C. furca, and P. minimum, whereas for C. polykrikoides and Gonyaulax polygramma the temperature and salinity ranges were narrow. The concentrations of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphate (DIP) in 1996-2000 were higher than the reported values for the half-saturation concentrations of uptake of nitrate and phosphate for most of the causative mixotrophic dinoflagellates. However, the concentrations of DIN and DIP have decreased gradually since 2000 and the frequency of mixotrophic dinoflagellate red tides has also decreased. Thus, DIN and DIP are likely to be the primary factors influencing the frequency of mixotrophic dinoflagellate red tides in Korean waters. Five novel dinoflagellate species have been discovered in Korean coastal waters since 2005 and their morphological and molecular characteristics have been described as new genera and species. It is thus necessary to monitor their dynamics to investigate whether they can form red tides. © 2013 Elsevier B.V.

Sato P.Y.,Temple University | Sato P.Y.,Advanced Institutes of Convergence Technology | Chuprun J.K.,Temple University | Chuprun J.K.,Advanced Institutes of Convergence Technology | And 4 more authors.
Physiological Reviews | Year: 2015

G protein-coupled receptors (GPCRs) are important regulators of various cellular functions via activation of intracellular signaling events. Active GPCR signaling is shut down by GPCR kinases (GRKs) and subsequent-arrestin-mediated mechanisms including phosphorylation, internalization, and either receptor degradation or resensitization. The seven-member GRK family varies in their structural composition, cellular localization, function, and mechanism of action (see sect. II). Here, we focus our attention on GRKs in particular canonical and novel roles of the GRKs found in the cardiovascular system (see sects. III and IV). Paramount to overall cardiac function is GPCR-mediated signaling provided by the adrenergic system. Overstimulation of the adrenergic system has been highly implicated in various etiologies of cardiovascular disease including hypertension and heart failure. GRKs acting downstream of heightened adrenergic signaling appear to be key players in cardiac homeostasis and disease progression, and herein we review the current data on GRKs related to cardiac disease and discuss their potential in the development of novel therapeutic strategies in cardiac diseases including heart failure. © 2015 the American Physiological Society.

Yeungnam University and Advanced Institutes Of Convergence Technology | Date: 2012-12-13

There is provided a Database method for a B+ tree based on a PRAM. The database method is characterized of dividing each node into area 1 and area 2; inserting/retrieving/deleting a certain key value for the each node. Inserting a key value is characterized of firstly inserting a new key value to area 2, if area 2 in the node is not in a full state. Retrieving a key value is characterized of identifying whether the node is a leaf node; and if the node is a leaf node, retrieving area 1 and area 2 sequentially. Deleting a key value is characterized of: merging area 1 and area 2 in the node; and deleting a key value in the merged node. Therefore, the present disclosure provides advantages of enhancing durability and data processing capability.

Lee E.,Korea Advanced Institute of Science and Technology | Kim C.,Korea Advanced Institute of Science and Technology | Kim C.,Advanced Institutes of Convergence Technology
Optics Express | Year: 2012

We perform a systematic analysis of enhanced short-circuit current density (Jsc) in organic solar cells (OSCs) where one metallic electrode is optically thick and the other consists of a two-dimensional metallic crossed grating. By examining a model device representative of such surface plasmon (SP)-enhanced OSCs by the Fourier modal and finite-element methods for electromagnetic and exciton diffusion calculations, respectively, we provide general guidelines to maximize Jsc of the SP-enhanced OSCs. Based on this study, we optimize the performance of a small-molecule OSC employing a copper phthalocyanine-fullerene donor-acceptor pair, demonstrating that the optimized SP-enhanced device has Jsc that is 75 % larger than that of the optimized device with an ITO-based conventional structure. © 2012 Optical Society of America.

Advanced Institutes Of Convergence Technology | Date: 2012-04-09

The present disclosure relates to a folding structure for two-wheeled vehicle, comprising: a front wheel; a rear wheel; a first connection rod connected to the front wheel; a second connection rod connected to the rear wheel; a first rotary shaft for rotating the first connection rod relative to the second connection rod; and a second rotary shaft for rotating the front wheel relative to the first connection rod, wherein a space is formed by means of the rotation of the first connection rod relative to the first rotary shaft and the rotation of the front wheel relative to the second rotary shaft so as to allow the first connection rod and the second connection rod to be placed between the front wheel and the rear wheel.

Advanced Institutes Of Convergence Technology | Date: 2013-04-08

Disclosed is a transmission apparatus comprising: a sun gear connected to the input terminal; a plurality of first planetary gears engaging with an outer surface of the sun gear; a second planetary gear which forms a concentric circle with each first planetary gear, and which is integrally formed with the first planetary gears; a first ring gear engaging with outer surfaces of the first planetary gears and connected to the output terminal; a second ring gear engaging with an outer surface of the second planetary gear; a cage for supporting rotary shafts of the first and second planetary gears such that the first and second planetary gears can revolve about the sun gear; and a brake member.

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