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Search Results: 1 - 10 of 21196 matches for " Kyeoung-Hwa Kim "
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Function of COP9 Signalosome in Regulation of Mouse Oocytes Meiosis by Regulating MPF Activity and Securing Degradation
Eunju Kim, Se-Jin Yoon, Eun-Young Kim, Yunna Kim, Hyun-Seo Lee, Kyeoung-Hwa Kim, Kyung-Ah Lee
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025870
Abstract: The COP9 (constitutive photomorphogenic) signalosome (CSN), composed of eight subunits, is a highly conserved protein complex that regulates processes such as cell cycle progression and kinase signalling. Previously, we found the expression of the COP9 constitutive photomorphogenic homolog subunit 3 (CSN3) and subunit 5 (CSN5) changes as oocytes mature for the first time, and there is no report regarding roles of COP9 in the mammalian oocytes. Therefore, in the present study, we examined the effects of RNA interference (RNAi)-mediated transient knockdown of each subunit on the meiotic cell cycle in mice oocytes. Following knockdown of either CSN3 or CSN5, oocytes failed to complete meiosis I. These arrested oocytes exhibited a disrupted meiotic spindle and misarranged chromosomes. Moreover, down-regulation of each subunit disrupted the activity of maturation-promoting factor (MPF) and concurrently reduced degradation of the anaphase-promoting complex/cyclosome (APC/C) substrates Cyclin B1 and Securin. Our data suggest that the CSN3 and CSN5 are involved in oocyte meiosis by regulating degradation of Cyclin B1 and Securin via APC/C.
Gas6 Downregulation Impaired Cytoplasmic Maturation and Pronuclear Formation Independent to the MPF Activity
Kyeoung-Hwa Kim,Eun-Young Kim,Yuna Kim,Eunju Kim,Hyun-Seo Lee,Sook-Young Yoon,Kyung-Ah Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0023304
Abstract: Previously, we found that the growth arrest-specific gene 6 (Gas6) is more highly expressed in germinal vesicle (GV) oocytes than in metaphase II (MII) oocytes using annealing control primer (ACP)-PCR technology. The current study was undertaken to investigate the role of Gas6 in oocyte maturation and fertilization using RNA interference (RNAi). Interestingly, despite the specific and marked decrease in Gas6 mRNA and protein expression in GVs after Gas6 RNAi, nuclear maturation including spindle structures and chromosome segregation was not affected. The only discernible effect induced by Gas6 RNAi was a change in maturation promoting factor (MPF) activity. After parthenogenetic activation, Gas6 RNAi-treated oocytes at the MII stage had not developed further and arrested at MII (90.0%). After stimulation with Sr2+, Gas6-silenced MII oocytes had markedly reduced Ca2+ oscillation and exhibited no exocytosis of cortical granules. In these oocytes, sperm penetration occurred during fertilization but not pronucleus (PN) formation. By roscovitine and colcemid treatment, we found that the Gas6 knockdown affected cytoplasmic maturation directly, independent to the changed MPF activity. These results strongly suggest that 1) the Gas6 signaling itself is important to the cytoplasmic maturation, but not nuclear maturation, and 2) the decreased Gas6 expression and decreased MPF activity separately or mutually influence sperm head decondensation and PN formation.
Moreau-Yosida approximation and convergence of Hamiltonian systems on Wasserstein space
Hwa Kil Kim
Mathematics , 2012,
Abstract: In this paper, we study the stability property of Hamiltonian systems on the Wasserstein space. Let $H$ be a given Hamiltonian satisfying certain properties. We regularize $H$ using the Moreau-Yosida approximation and denote it by $H_\tau.$ We show that solutions of the Hamiltonian system for $H_\tau$ converge to a solution of the Hamiltonian system for $H$ as $\tau$ converges to zero. We provide sufficient conditions on $H$ to carry out this process.
A Meta-Analysis on the Application of SNS in Education for SMART Learning: Focusing on Korean Case  [PDF]
Soon-Hwa Kim, Ki-Sang Song
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.38B018
Abstract: As the Smart Phone and iPad type devices widely spread all over the world, the Social Network Service (SNS) has become prevalent. The SNS deeply penetrates into personal lives, it also affects learning and education. To evaluate the SNS effects on education, we have analyzed 153 articles from 2009 to 2012 published in Korea to know the current status of the application of the SNS on education in Korea. From this meta-analysis review, we found that the Wiki service is the most widely researched SNS service applicable to education in Korea, and information technology subject is the hottest discipline when considering SNS for education. Also, college level education is the most well prepared school type to use SNS for education. This review results suggest that the most appropriate level of applying smart education – education using smart phone or iPad type devices – is college level or above instead of K-12 education.
The Effects of Thinking Style Based Cooperative Learning on Group Creativity  [PDF]
Soon-Hwa Kim, Ki-Sang Song
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.38B005
Abstract: Recent studies have emphasized group creativity within a socio-cultural context rather than at an individual level, but not many researchers reported strategies for developing group creativity. This paper aims to explore strategies to enhance group creativity based on the theoretical basis of thinking styles by Sternberg. The hypothesis was that groups with members of diverse thinking styles would show greater gains in creative performance. In this study, the participants (n=72) were divided into 24 three-person groups. Each group was given the task to create a game using Scratch programming language. Among the 24 groups, eleven groups (n=33) consisted of heterogeneous thinking styles, and the other thirteen groups (n=39) consisted solely of homogeneous thinking styles. All divided groups performed same creative task. The empirical results supported the hypothesis that group formation of diverse thinking style shows better group creativity.
PIV Measurement of Velocity Distribution in the Moderator Circulation Test (MCT)  [PDF]
Hyoung Tae Kim, Bo Wook Rhee, Hwa-Lim Choi
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.29011
Abstract:

Korea Atomic Energy Research Institute (KAERI) has been carrying out a scaled-down moderator test program to simulate the CANDU-6 moderator circulation phenomena during steady state operation and accident conditions. The Moderator Circulation Test (MCT) facility was designed and constructed as 1/4 scale of the prototype of CANDU-6 reactor. In the present work spatial distribution of two-dimensional velocity in the MCT facility under isothermal condition was measured using planar Particle Image Velocimetry (PIV) system which consists of double pulsed laser, synchronizer, and high speed camera. TSI’s Insight TM 4G software was used to perform PIV image capturing, PIV calculation and post processing. 10 μm sized silver-coated hollow sphere particles were used as flow tracer particles. Multiple experiments were conducted to cover large area of the MCT facility with limited field of view of a single camera. Instantaneous and averaged velocity field were analyzed for each spatial position and flow rate. This research is capable of offering validation data for self-reliant CFD tools to predict moderator subcooling margin in CANDU-6 reactor.

A Class of Integral Operators Preserving Subordination and Superordination
Nak Eun Cho,In Hwa Kim
Journal of Inequalities and Applications , 2008, DOI: 10.1155/2008/859105
Abstract: We give some subordination- and superordination-preserving properties of certain nonlinear integral operators defined on the space of normalized analytic functions in the open unit disk. The sandwich-type theorems for these integral operators are also obtained. Moreover, we consider an application of the subordination and superordination theorems to the Gauss hypergeometric function.
Conditions for Carathéodory Functions
Nak Eun Cho,In Hwa Kim
Journal of Inequalities and Applications , 2009, DOI: 10.1155/2009/601597
Abstract: The purpose of the present paper is to derive some sufficient conditions for Carathéodory functions in the open unit disk. Our results include several interesting corollaries as special cases.
Value functions in the Wasserstein spaces: finite time horizons
Ryan Hynd,Hwa Kil Kim
Mathematics , 2013,
Abstract: We study analogs of value functions arising in classical mechanics in the space of probability measures endowed with the Wasserstein metric $W_p$, for $1
Infinite horizon value functions in the Wasserstein spaces
Ryan Hynd,Hwa Kil Kim
Mathematics , 2013,
Abstract: We perform a systematic study of optimization problems in the Wasserstein spaces that are analogs of infinite horizon, deterministic control problems. We derive necessary conditions on action minimizing paths and present a sufficient condition for their existence. We also verify that the corresponding generalized value functions are a type of viscosity solution of a time independent, Hamilton-Jacobi equation in the space of probability measures. Finally, we prove a special case of a conjecture involving the subdifferential of generalized value functions and their relation to action minimizing paths.
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