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Search Results: 1 - 10 of 6885 matches for " Sang Woo Oh "
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Abelian Decomposition of General Relativity
Y. M. Cho,S. H. Oh,Sang-Woo Kim
Physics , 2011,
Abstract: Based on the view that Einstein's theory can be interpreted as a gauge theory of Lorentz group, we decompose the gravitational connection (the gauge potential of Lorentz group) $\vGm_\mu$ into the restricted connection made of the potential of the maximal Abelian subgroup $H$ of Lorentz group $G$ and the valence connection made of $G/H$ part of the potential which transforms covariantly under Lorentz gauge transformation. With this decomposition we show that the Einstein's theory can be decomposed into the restricted part made of the restricted connection which has the full Lorentz gauge invariance and the valence part made of the valence connection which plays the role of gravitational source of the restricted gravity. We show that there are two different Abelian decomposition of Einstein's theory, the light-like (or null) decomposition and the non light-like (or non-null) decomposition, because Lorentz group has two maximal Abelian subgroups. In this decomposition the role of the metric $g_\mn$ is replaced by a four-index metric tensor $\vg_\mn$ which transforms covariantly under the Lorentz group, and the metric-compatibility condition $\nabla_\alpha g_\mn=0$ of the connection is replaced by the gauge and generally covariant condition ${\mathscr D}_\mu \vg^\mn=0$. The decomposition shows the existence of a restricted theory of gravitation which has the full general invariance but is much simpler and has less physical degrees of freedom than Einstein's theory. Moreover, it tells that the restricted gravity can be written as an Abelian gauge theory, which implies that the graviton can be described by a massless spin-one field.
Intracellular Cleavage of Amyloid β by a Viral Protease NIa Prevents Amyloid β-Mediated Cytotoxicity
Baehyun Shin, Hyejin Oh, Sang Min Park, Hye-Eun Han, Michael Ye, Woo Keun Song, Woo Jin Park
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0098650
Abstract: Nuclear inclusion a (NIa) of turnip mosaic virus is a cytosolic protease that cleaves amyloid β (Aβ) when heterologously overexpressed. Lentivirus-mediated expression of NIa in the brains of APP(sw)/PS1 mice significantly reduces cerebral Aβ levels and plaque depositions, and improves behavioral deficits. Here, the effects of NIa and neprilysin (NEP), a well-known Aβ-cleaving protease, on oligomeric Aβ-induced cell death were evaluated. NIa cleaved monomeric and oligomeric Aβ at a similar rate, whereas NEP only cleaved monomeric Aβ. Oligomeric Aβ-induced cytotoxicity and mitochondrial dysfunction were significantly ameliorated by NIa, but not by NEP. Endocytosed fluorescently-labeled Aβ localized to mitochondria, and this was significantly reduced by NIa, but not by NEP. These data suggest that NIa may exerts its protective roles by degrading Aβ and thus preventing mitochondrial deposition of Aβ.
Structural Studies and Optical and Electrical Properties of Novel -Doped Nanorods
Abdolali Alemi,Younes Hanifehpour,Sang Woo Joo,Bong-Ki Min,Tae Hwan Oh
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/983150
Abstract: Gd3
Progranulin as a Prognostic Biomarker for Breast Cancer Recurrence in Patients Who Had Hormone Receptor-Positive Tumors: A Cohort Study
Dong Hoe Koo, Cheol-Young Park, Eun Sook Lee, Jungsil Ro, Sang Woo Oh
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039880
Abstract: Background Progranulin (PGRN) is considered to play an important role in breast cancer tumorigenesis and in inhibiting tamoxifen-induced apoptosis. We aimed to determine whether PGRN levels are associated with breast cancer recurrence after curative surgery. Methodology/Principal Findings We evaluated the associations between preoperative serum PGRN levels and breast cancer recurrence in a cohort of 697 newly diagnosed breast cancer patients who underwent curative surgery between April 2001 and December 2004. The mean age ± standard deviation (SD) was 46±9.8 years, and all patients with hormone receptor (HR)-positive tumors received adjuvant tamoxifen therapy. At a median follow-up of 62.2 months (range, 2.9–98.2), 89 patients (12.8%) had experienced a recurrence and 51 patients (7.3%) had died. In the HR-positive group, serum PGRN levels were associated with recurrence according to the log-rank test for trend (p for trend = 0.049). There was no association between PGRN levels and recurrence in the HR-negative group (p for trend = 0.658). Adjusted hazard ratios, including possible confounders, revealed a linear relationship between serum PGRN levels and recurrence in the HR-positive group (p for trend = 0.049), and this association was further strengthened after excluding patients who had no lymph node metastasis (p for trend = 0.038). Conclusions/Significance Serum PGRN levels were clinically significant for predicting recurrence in patients with HR-positive breast cancer during adjuvant tamoxifen therapy.
A Miniaturized Magnetic Induction Sensor Using Geomagnetism for Turn Count of Small-Caliber Ammunition
Sang-Hee Yoon,Seok-Woo Lee,Young-Ho Lee,Jong-Soo Oh
Sensors , 2006, DOI: 10.3390/s6070712
Abstract: This paper presents a miniaturized magnetic induction sensor (MMIS), wheregeomagnetism and high rpm rotation of ammunition are used to detect the turn number ofthe ammunition for applications to small-caliber turn-counting fuzes. The MMIS, composedof cores and a coil, has a robust structure without moving parts to increase the shocksurvivability in a gunfire environment of ~30,000 g’s. The MMIS is designed and fabricatedon the basis of the simulation results of an electromagnetic analysis tool, Maxwell? 3D. Inthe experimental study, static MMIS test using a solenoid-coil apparatus and dynamicMMIS test (firing test) have been made. The present MMIS has shown that an inductionvoltage of 6.5 mVp-p is generated at a magnetic flux density of 0.05 mT and a rotationalvelocity of 30,000 rpm. From the measured signal, MMIS has shown a signal-to-noise ratioof 44.0 dB, a nonlinearity of 0.59%, a frequency-normalized sensitivity of 0.256±0.010V/T·Hz and a drift of 0.27% in the temperature range of -30~ 43°C. Firing test has shownthat the MMIS can be used as a turn-counting sensor for small-caliber ammunition,verifying the shock survivability of the MMIS in a high-g environment.
Recovery of the mitochondrial COI barcode region in diverse Hexapoda through tRNA-based primers
Doo-Sang Park, Soo-Jung Suh, Hyun-Woo Oh, Paul DN Hebert
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-423
Abstract: Two forward PCR primers were developed following analysis of all known arthropod mitochondrial genome arrangements and sequence alignment of the tRNA-W gene which was usually located within 200 bp upstream of the COI gene. These two primers were combined with a standard reverse primer (LepR1) to produce a cocktail which generated a barcode amplicon from 125 of 141 species that included representatives of 121 different families of Hexapoda. High quality sequences were recovered from 79% of the species including groups, such as scale insects, that invariably fail to amplify with standard primers.A cocktail of two tRNA-W forward primers coupled with a standard reverse primer amplifies COI for most hexapods, allowing characterization of the standard barcode primer binding region in COI 5' as well as the barcode segment. The current results show that primers designed to bind to highly conserved gene regions upstream of COI will aid the amplification of this gene region in species where standard primers fail and provide valuable information to design a primer for problem groups.Since 2003, substantial effort has been directed toward the development of a DNA-based identification system for animal life, based upon the analysis of sequence diversity in the 5' region of the mitochondrial gene, cytochrome c oxidase 1 [1,2]. Termed DNA barcoding, this approach relies upon the PCR amplification of the target gene region and its subsequent sequence characterization. Performance tests on numerous animal groups have established that the system ordinarily works well - sequence diversity in the 5' region of COI enables discrimination of more than 98% of animal species [3,4]. However, past work has also revealed that standard primer cocktails fail to generate a PCR amplicon in certain taxonomic groups. In some cases, amplification success has been so low that researchers have suggested the need to study slower evolving gene regions that can be recovered more easily [5,6]. Because such
Retiform Hemangioendothelioma on the Finger
Woo Kyung Choi,Sung Hwan Lee,Sang Ah Oh,Dong Hee Kang
Archives of Plastic Surgery , 2012, DOI: http://dx.doi.org/10.5999/aps.2012.39.1.80
Dual Memory Architectures for Fast Deep Learning of Stream Data via an Online-Incremental-Transfer Strategy
Sang-Woo Lee,Min-Oh Heo,Jiwon Kim,Jeonghee Kim,Byoung-Tak Zhang
Computer Science , 2015,
Abstract: The online learning of deep neural networks is an interesting problem of machine learning because, for example, major IT companies want to manage the information of the massive data uploaded on the web daily, and this technology can contribute to the next generation of lifelong learning. We aim to train deep models from new data that consists of new classes, distributions, and tasks at minimal computational cost, which we call online deep learning. Unfortunately, deep neural network learning through classical online and incremental methods does not work well in both theory and practice. In this paper, we introduce dual memory architectures for online incremental deep learning. The proposed architecture consists of deep representation learners and fast learnable shallow kernel networks, both of which synergize to track the information of new data. During the training phase, we use various online, incremental ensemble, and transfer learning techniques in order to achieve lower error of the architecture. On the MNIST, CIFAR-10, and ImageNet image recognition tasks, the proposed dual memory architectures performs much better than the classical online and incremental ensemble algorithm, and their accuracies are similar to that of the batch learner.
Cigarette Smoking Increases Abdominal and Visceral Obesity but Not Overall Fatness: An Observational Study
Jung Hwan Kim, Kyung Won Shim, Yeong Sook Yoon, Sang Yeoup Lee, Sung Soo Kim, Sang Woo Oh
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045815
Abstract: Background Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity. Methodology/Principal Findings Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size. Conclusions/Significance Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications.
Inclusion and Argument Properties for Certain Subclasses of Analytic Functions Defined by Using on Extended Multiplier Transformations  [PDF]
Oh Sang Kwon
Advances in Pure Mathematics (APM) , 2011, DOI: 10.4236/apm.2011.14034
Abstract: Making use of a multiplier transformation, which is defined by means of the Hadamard product (or convolution), we introduce some new subclasses of analytic functions and investigate their inclusion relationships and argument properties.
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