oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 13 )

2018 ( 141 )

2017 ( 134 )

2016 ( 128 )

Custom range...

Search Results: 1 - 10 of 14220 matches for " Jung-Gu Hur "
All listed articles are free for downloading (OA Articles)
Page 1 /14220
Display every page Item
TRAIL sensitize MDR cells to MDR-related drugs by down-regulation of P-glycoprotein through inhibition of DNA-PKcs/Akt/GSK-3β pathway and activation of caspases
Suk-Bin Seo, Jung-Gu Hur, Mi-Ju Kim, Jae-Won Lee, Hak-Bong Kim, Jae-Ho Bae, Dong-Wan Kim, Chi-Dug Kang, Sun-Hee Kim
Molecular Cancer , 2010, DOI: 10.1186/1476-4598-9-199
Abstract: MDR variants, CEM/VLB10-2, CEM/VLB55-8 and CEM/VLB100 cells, with gradually increased levels of P-gp derived from human lymphoblastic leukemia CEM cells, were gradually more susceptible to TRAIL-induced apoptosis and cytotoxicity than parental CEM cells. The P-gp level of MDR variants was positively correlated with the levels of DNA-PKcs, pAkt, pGSK-3β and c-Myc as well as DR5 and negatively correlated with the level of c-FLIPs. Hypersensitivity of CEM/VLB100 cells to TRAIL was accompanied by the activation of mitochondrial apoptotic pathway as well as the activation of initiator caspases. In addition, TRAIL-induced down-regulation of DNA-PKcs/Akt/GSK-3β pathway and c-FLIP and up-regulation of cell surface expression of death receptors were associated with the increased susceptibility to TRAIL of MDR cells. Moreover, TRAIL inhibited P-gp efflux function via caspase-3-dependent degradation of P-gp as well as DNA-PKcs and subsequently sensitized MDR cells to MDR-related drugs such as vinblastine and doxorubicin. We also found that suppression of DNA-PKcs by siRNA enhanced the susceptibility of MDR cells to vincristine as well as TRAIL via down-regulation of c-FLIP and P-gp expression and up-regulation of DR5.This study showed for the first time that the MDR variant of CEM cells was hypersensitive to TRAIL due to up-regulation of DR5 and concomitant down-regulation of c-FLIP, and degradation of P-gp and DNA-PKcs by activation of caspase-3 might be important determinants of TRAIL-induced sensitization of MDR cells to MDR-related drugs. Therefore, combination of TRAIL and chemotherapeutic drugs may be a good strategy for treatment of cancer with multidrug resistance.Acquired resistance to chemotherapeutic agents remains a major obstacle for the effective treatment of many advanced and metastatic cancers. Several mechanisms are thought to be involved in the development of multidrug resistance (MDR), defined by simultaneous cross-resistance to a variety of anticancer drugs
A novel de novo mutation in the serine-threonine kinase STK11 gene in a Korean patient with Peutz-Jeghers syndrome
Jong-Ha Yoo, Jee-Hyoung Yoo, Yoon-Jung Choi, Jung-Gu Kang, Young-Kyu Sun, Chang-Seok Ki, Kyung-A Lee, Jong-Rak Choi
BMC Medical Genetics , 2008, DOI: 10.1186/1471-2350-9-44
Abstract: Using DNA samples obtained from the patient and his family members, we sequenced nine exons and flanking intron regions of the STK11 gene using polymerase chain reaction (PCR) and direct sequencing.Sequencing of the STK11 gene in the proband of the family revealed a novel 1-base pair deletion of guanine (G) in exon 6 (c.826delG; Gly276AlafsX11). This mutation resulted in a premature termination at codon 286, predicting a partial loss of the kinase domain and complete loss of the C-terminal domain. We did not observe this mutation in both parents of the PJS patient. Therefore, it is considered a novel de novo mutation.The results presented herein enlarge the spectrum of mutations of the STK11 gene by identifying a novel de novo mutation in a PJS patient and further support the hypothesis that STK11 mutations are disease-causing mutations for PJS with or without a positive family history.Peutz-Jeghers syndrome (PJS; OMIM 175200) is a rare, autosomal dominant disorder characterized by melanocytic macules of the lips, buccal mucosa, and digits, along with multiple gastrointestinal hamartomatous polyps, frequently in the small intestine [1,2]. Patients with PJS are at an increased risk of developing gastrointestinal cancer and extraintestinal neoplasms involving organs such as the ovaries, testes, breasts, pancreas, lungs, or uterine cervix [3].Currently, only mutations in the gene STK11 (also known as LKB1; OMIM 602216) at chromosome 19p13.3 have been identified as a cause of PJS [4,5]. The human STK11 gene encodes a 433 amino acid serine-threonine kinase. STK11 is known to be located both in the nucleus and the cytoplasm of all human tissues [6], and orthologs include mouse LKb1 [7], XEEK1 (Xenopus egg and embryo kinase 1) [8], Caenorhabditis elegans partitioning defective gene 4 (par-4) [9], and drosophila Lkb1 [10].Loss of the normal allele has been observed in polyps from patients with PJS, and loss of heterozygosity (LOH) has been noted to occur in some tumor tissu
Molecular and Clinical Characterization of the Variable Phenotype in Korean Families with Hearing Loss Associated with the Mitochondrial A1555G Mutation
Jae Woong Bae, Dong-Bin Kim, Jae Young Choi, Hong-Joon Park, Jong Dae Lee, Dong Gu Hur, Seung-Hyun Bae, Da Jung Jung, Sang Heun Lee, Un-Kyung Kim, Kyu Yup Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042463
Abstract: Hearing loss, which is genetically heterogeneous, can be caused by mutations in the mitochondrial DNA (mtDNA). The A1555G mutation of the 12S ribosomal RNA (rRNA) gene in the mtDNA has been associated with both aminoglycoside-induced and non-syndromic hearing loss in many ethnic populations. Here, we report for the first time the clinical and genetic characterization of nine Korean pedigrees with aminoglycoside-induced and non-syndromic hearing loss. These Korean families carry in the A1555G mutation of 12S rRNA gene and exhibit variable penetrance and expressivity of hearing loss. Specifically, the penetrance of hearing loss in these families ranged between 28.6% and 75%, with an average of 60.8%. These results were higher than the 29.8% penetrance that was previously reported in a Chinese population but similar to the 65.4% and 54.1% penetrance observed in a large Arab-Israeli population and nineteen Spanish pedigrees, respectively. The mutational analysis of the complete mtDNA genome in these families showed that the haplogroups of the Korean population, which belongs to the eastern Asian population, were similar to those of the Chinese population but different from the Spanish population, which belongs to the European-Caucasian population. The mtDNA variants that may act as modifier factors were also found to be similar to the Chinese population. Although the mtDNA haplogroups and variants were similar to the eastern Asian population, we did find some differing phenotypes, although some subjects had the same variants. This result suggests that both the ethnic background and environmental factors lead to a variable phenotype of the A1555G mutation.
On the Empirical Estimation of Utility Distribution Damping Parameters Using Power Quality Waveform Data
Hur Kyeon,Santoso Surya,Gu Irene YH
EURASIP Journal on Advances in Signal Processing , 2007,
Abstract: This paper describes an efficient yet accurate methodology for estimating system damping. The proposed technique is based on linear dynamic system theory and the Hilbert damping analysis. The proposed technique requires capacitor switching waveforms only. The detected envelope of the intrinsic transient portion of the voltage waveform after capacitor bank energizing and its decay rate along with the damped resonant frequency are used to quantify effective X/R ratio of a system. Thus, the proposed method provides complete knowledge of system impedance characteristics. The estimated system damping can also be used to evaluate the system vulnerability to various PQ disturbances, particularly resonance phenomena, so that a utility may take preventive measures and improve PQ of the system.
Quantum Localization in Open Chaotic Systems
Jung-Wan Ryu,G. Hur,Sang Wook Kim
Physics , 2008, DOI: 10.1103/PhysRevE.78.037201
Abstract: We study a quasi-Floquet state of a $\delta$-kicked rotor with absorbing boundaries focusing on the nature of the dynamical localization in open quantum systems. The localization lengths $\xi$ of lossy quasi-Floquet states located near the absorbing boundaries decrease as they approach the boundary while the corresponding decay rates $\Gamma$ are dramatically enhanced. We find the relation $\xi \sim \Gamma^{-1/2}$ and explain it based upon the finite time diffusion, which can also be applied to a random unitary operator model. We conjecture that this idea is valid for the system exhibiting both the diffusion in classical dynamics and the exponential localization in quantum mechanics.
On the Empirical Estimation of Utility Distribution Damping Parameters Using Power Quality Waveform Data
Kyeon Hur,Surya Santoso,Irene Y. H. Gu
EURASIP Journal on Advances in Signal Processing , 2007, DOI: 10.1155/2007/95328
Abstract: This paper describes an efficient yet accurate methodology for estimating system damping. The proposed technique is based on linear dynamic system theory and the Hilbert damping analysis. The proposed technique requires capacitor switching waveforms only. The detected envelope of the intrinsic transient portion of the voltage waveform after capacitor bank energizing and its decay rate along with the damped resonant frequency are used to quantify effective X/R ratio of a system. Thus, the proposed method provides complete knowledge of system impedance characteristics. The estimated system damping can also be used to evaluate the system vulnerability to various PQ disturbances, particularly resonance phenomena, so that a utility may take preventive measures and improve PQ of the system.
Electroweak symmetry breaking and cold dark matter from strongly interacting hidden sector
Hur, Taeil;Jung, Dong-Won;Ko, P.;Lee, Jae Yong
High Energy Physics - Phenomenology , 2007, DOI: 10.1016/j.physletb.2010.12.047
Abstract: We consider a hidden sector with a vectorlike confining gauge theory like QCD with $N_{h,c}$ colors and $N_{h,f}$ light quarks ${\cal Q}_h$ in the hidden sector. Then a scale $\Lambda_H$ would be generated by dimensional transmutation, and chiral symmetry breaking occurs in the hidden sector. This scale $\Lambda_H$ can play a role of the SM Higgs mass parameter, triggering electroweak symmetry breaking (EWSB). Furthermore the lightest mesons in the hidden sector is stable by flavor conservation of the hidden sector strong interaction, and could be a good cold dark matter (CDM). We study collider phenomenology, and relic density and direct detection rates of the CDM of this model.
Perforation of the colon by invading recurrent gastrointestinal stromal tumors during sunitinib treatment
Hoon Hur, Ae Ryoung Park, Sung Bae Jee, Seung Eun Jung, Wook Kim, Hae Myung Jeon
World Journal of Gastroenterology , 2008,
Abstract: The molecular targets of sunitinib are receptor tyrosine kinases (RTKs), and this drug has also been known to exert blocking effects on the activation of KIT, which is similar to the mechanism of action of imatinib. Moreover, sunitinib has an additional anti-angiogenic effect through its inhibition of the vascular endothelial growth factor receptor activation. We report here a 70-year-old patient diagnosed with a recurrent gastrointestinal stromal tumor (GIST), which invaded the transverse colon and led to a perforation during sunitinib treatment. A computed tomography scan and 3-dimensional reconstruction showed necrosis of the recurrent hepatic mass and perforation of the invaded transverse colon. After percutaneous drainage of the intraperitoneal abscess, antibiotic treatment and restricted diet, the condition of the patient improved. The present case is the first to report that sunitinib, which is administered to treat GIST resistant to imatinib, can cause unexpected colon perforation and subsequent peritonitis.
Development of a Multi-Channel Piezoelectric Acoustic Sensor Based on an Artificial Basilar Membrane
Youngdo Jung,Jun-Hyuk Kwak,Young Hwa Lee,Wan Doo Kim,Shin Hur
Sensors , 2014, DOI: 10.3390/s140100117
Abstract: In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS) that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA) was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz–13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters.
Polyol-Free Synthesis of Uniformly Dispersed Pt/Graphene Oxide Electrocatalyst by Sulfuric Acid Treatment
Tae Kyu Lee,Hyang Jin Park,Min Ki Kwon,Ju Hae Jung,Junbom Kim,Seung Hyun Hur
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/418737
Abstract: Polyol-free synthesis of highly loaded Pt catalysts on sulfuric-acid-treated graphene oxide (SGO) was reported. Sulfuric acid treatment increased the surface hydroxyl groups on graphene oxide (GO), which contributed to the reduction of Pt precursors in the absence of external reducing agent. By adjusting pH during the Pt reduction, we can get uniformly dispersed 2.5?nm size Pt nanoparticles on GO surface even at 50?wt% Pt loading amount. Cyclic voltammetry showed that increased pH resulted in increased electrochemical surface area. 1. Introduction Polymer electrolyte membrane fuel cell (PEMFC) is regarded as one of the best candidates for the future energy sources as it can generate the electricity in a carbon-free way through the carbon dioxide free electrochemical reaction. Generally, only hydrogen and oxygen (or air) are used as the fuel gas and the oxidant gas, respectively. Moreover, the product generated during this reaction is only pure water, which will not cause any harms to the environment and also can be used as the essential ingredient for human and nature [1]. Nevertheless, its high cost impedes the commercialization. To reduce materials cost by improving the catalyst performance, robust catalytic supporting materials must be developed to achieve high dispersion, utilization, activity, and stability [2]. Recently, the majority of the catalyst support research has focused on the use of graphitic materials such as carbon nanotube and graphene [3–5]. Graphene is extensively studied due to its excellent properties such as a large theoretical specific surface area, high intrinsic mobility, high Young’s modulus and thermal conductivity, and its optical transmittance and good electrical conductivity [6–9]. There are several pathways to fabricate graphene nanosheets including chemical vapor deposition, mechanical exfoliation, and chemical exfoliation; among them chemical exfoliation is regarded as the most suitable one for fuel cell application due to its versatility of their surface modifications, unique defect behaviors, functional groups, and advantages associated with low cost and easy scale up [10]. The Pt catalyst for PEMFC can be prepared by impregnation, polyol, and colloidal method [11, 12]. Generally, wet impregnation followed by reduction by gaseous hydrogen atmosphere at high temperatures or the chemical reduction of the metal precursors using reducing agents can be used but achieving small particle size and uniform size distribution of Pt in this ways is very difficult especially at high Pt loading amount. Instead, the colloidal method
Page 1 /14220
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.