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Kim D.-J.,KAIST | Kim S.-I.,KBSI | Park S.-Y.,KBSI | Lee K.-D.,KAIST | Park B.-G.,KAIST
Current Applied Physics | Year: 2014

The relative contribution of spin pumping and spin rectification from the ferromagnetic resonance of CoFeB/non-magnetic bilayers was investigated as a function of non-magnetic electrode resistance. Samples with highly resistive electrodes of Ta or Ti exhibit a stronger spin rectification signal, which may result in over-(or under-) estimation of the spin Hall angle of the materials, while those with low resistive electrodes of Pt or Pd show the domination of the inverse spin Hall effect from spin pumping. By comparison with samples of single FM layer and an inverted structure, we provide a proper analysis method to extract spin pumping contribution. © 2014 Elsevier B.V. All rights reserved.


Yoon H.,KAIST | Lee A.T.,KAIST | Choi E.-A.,KAIST | Seo K.,KAIST | And 5 more authors.
Journal of the American Chemical Society | Year: 2010

Single-crystalline free-standing hexagonal Fe1.3Ge nanowires (NWs) are synthesized for the first time using a chemical vapor transport process without using any catalyst. Interestingly, Fe1.3Ge NWs are found to be ferromagnetic at room temperature, while bulk Fe1.3Ge has the lower critical temperature of 200 K. We perform first-principles density functional calculations and suggest that the observed strong ferromagnetism is attributed to the reduced distances between Fe atoms, increased number of Fe-Fe bonds, and the enhanced Fe magnetic moments. Both experimental and theoretical studies show that the magnetic moments are enhanced in the NWs, as compared to bulk Fe1.3Ge. We also modulate the composition ratio of as-grown iron germanide NWs by adjusting experimental conditions. It is shown that uniaxial strain on the hexagonal plane also enhances the ferromagnetic stability. © 2010 American Chemical Society.


News Article | February 28, 2017
Site: www.eurekalert.org

Alzheimer's disease (AD) is one of the most common form of dementia. In search for new drugs for AD, the research team, led by Professor Mi Hee Lim of Natural Science at UNIST has developed a metal-based substance that works like a pair of genetic scissors to cut out amyloid-β (Aβ), the hallmark protein of AD. The study has been featured on the cover of the January 2017 issue of the Journal of the American Chemical Society (JACS) and has been also selected as a JACS Spotlight article. Alzheimer's disease is the sixth leading cause of death among in older adults. The exact causes of Alzheimer's disease are still unknown, but several factors are presumed to be causative agents. Among these, the aggregation of amyloid-β peptide (Aβ) has been implicated as a contributor to the formation of neuritic plaques, which are pathological hallmarks of Alzheimer's disease (AD). As therapeutics for AD, Professor Lim suggested a strategy that uses matal-based complexes for reducing the toxicity of the amyloid beta (Aβ). Althought various metal complexs have been suggested as therapeutics for AD, none of them work effectively in vivo. The research team has found that they can hydrolyze amyloid-beta proteins using a crystal structure, called tetra-N methylated cyclam (TMC). Hydrolysis is the process that uses water molecules to split other molecules apart. The metal-mediated TMC structure uses the external water and cut off the binding of amyloid-beta protein effectively. In this study, the following four metals (cobalt, nickel, copper and zinc) were placed at the center of the TMC structure. When the double-layered cobalt was added to the center, the hydrolysis activity was at the highest. The research team reported that the cobalt-based metal complex (Co(II)(TMC)) had the potential to penetrate the blood brain barrier and the hydrolysis activity for nonamyloid protein was low. Moreover, the effects of this substance on the toxicity of amyloid-beta protein were also observed in living cell experiments. "This material has a high therapeutic potential in the treatment of Alzheimer's disease as it can penetrate the brain-vascular barrier and directly interact with the amyloid-beta protein in the brain," says Professor Lim. This study has also attracted attention by the editor of the Journal of the American Chemical Society. "Not only do they develop new materials, but they have been able to propose details of the working principles and experiments that support them," according to the editor. "As a scientist, this is such a great honor to know that our recent publication in JACS was highlighted in JACS Spotlights," says Professor Lim. "This means that our research has not only been recognized as an important research, but also has caused a stir in academia." This study has been conducted in collaboration with Professor Jaeheung Cho of Daegu Gyeongbuk Institute of Science and Technology (DGIST), Professor Kiyoung Park of Korea Advanced Institute of Science and Technology (KAIST), and Dr. Sun Hee Kim of Korea Basic Science Institute (KBSI). It has been also supporte by the National Research Foundation of Korea (NRF) and the Ministry of Science, ICT and Future Planning (MSIP). Jeffrey S. Derrick et al., "Mechanistic Insights into Tunable Metal-Mediated Hydrolysis of Amyloid-β Peptides", JACS, (2017).


Erraguntla M.,KBSI | Tomasulo P.,Blood Systems Inc. | Land K.,Blood Systems Inc. | Kamel H.,Blood Systems Inc. | And 4 more authors.
Proceedings of the Annual Hawaii International Conference on System Sciences | Year: 2014

Blood donation is a voluntary activity in the United States and provides critical blood units for transfusions. Blood is collected, processed and transported by blood centers to hospitals, though some hospitals also collect blood directly from donors. Blood donation is very safe, but a small percentage of donors can have reactions and some of these reactions can lead to serious injury. Donor hemovigilance is the surveillance and analysis of donor reactions with the goal of understanding the factors influencing reactions and indentifying steps to improve donor safety [9]. Historically in the U.S., donor hemovigilance is managed by individual collection centers to improve their specific organization's donation processes. The Department of Health and Human Services (HHS) has developed a software tool (called DonorHART™) to collect, organize and analyze reactions that occur at different participating blood centers and hospitals [6, 8]. Data mining is used to analyze factors influencing the donor reactions, and the insights are shared with the community to help blood center and hospital managers and quality improvement administrators undertake interventions to improve donor safety [10]. The paper presents the history of the donor hemovigilance development and two data mining efforts performed on the data collected to improve the safety of blood donation processes. © 2014 IEEE.


Lee A.-R.,Gyeongsang National University | Park C.-J.,Gwangju Institute of Science and Technology | Cheong H.-K.,KBSI | Ryu K.-S.,KBSI | And 6 more authors.
Nucleic Acids Research | Year: 2016

Z-DNA binding proteins (ZBPs) play important roles in RNA editing, innate immune response and viral infection. Structural and biophysical studies show that ZBPs initially form an intermediate complex with B-DNA for B-Z conversion. However, a comprehensive understanding of the mechanism of Z-DNA binding and B-Z transition is still lacking, due to the absence of structural information on the intermediate complex. Here, we report the solution structure of the Zα domain of the ZBP-containing protein kinase from Carassius auratus (caZαPKZ). We quantitatively determined the binding affinity of caZαPKZ for both B-DNA and Z-DNA and characterized its B-Z transition activity, which is modulated by varying the salt concentration. Our results suggest that the intermediate complex formed by caZαPKZ and B-DNA can be used as molecular ruler, to measure the degree to which DNA transitions to the Z isoform. © 2016 The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.


PubMed | Gyeongsang National University, Sungkyunkwan University, Gwangju Institute of Science and Technology, Korea Advanced Institute of Science and Technology and KBSI
Type: Journal Article | Journal: Nucleic acids research | Year: 2016

Z-DNA binding proteins (ZBPs) play important roles in RNA editing, innate immune response and viral infection. Structural and biophysical studies show that ZBPs initially form an intermediate complex with B-DNA for B-Z conversion. However, a comprehensive understanding of the mechanism of Z-DNA binding and B-Z transition is still lacking, due to the absence of structural information on the intermediate complex. Here, we report the solution structure of the Z domain of the ZBP-containing protein kinase from Carassius auratus(caZPKZ). We quantitatively determined the binding affinity of caZPKZ for both B-DNA and Z-DNA and characterized its B-Z transition activity, which is modulated by varying the salt concentration. Our results suggest that the intermediate complex formed by caZPKZ and B-DNA can be used as molecular ruler, to measure the degree to which DNA transitions to the Z isoform.


PubMed | Gyeongsang National University, KBSI, Kyoto University and Gwangju Institute of Science and Technology
Type: Journal Article | Journal: Biochemical and biophysical research communications | Year: 2016

A Z-DNA binding protein (ZBP)-containing protein kinase (PKZ) in fish species has an important role in the innate immune response. Previous structural studies of the Z domain of the PKZ from Carassius auratus (caZ


PubMed | Gyeongsang National University, Gwangju Institute of Science and Technology, Hanyang University, Dongguk University and KBSI
Type: Letter | Journal: FEBS letters | Year: 2016

The quaternary-amino-ethyl 1 (QAE1) isoforms of type III antifreeze proteins (AFPs) prevent the growth of ice crystals within organisms living in polar regions. We determined the antifreeze activity of wild-type and mutant constructs of the Japanese notched-fin eelpout (Zoarces elongates Kner) AFP8 (nfeAFP8) and characterized the structural and dynamics properties of their ice-binding surface using NMR. We found that the three constructs containing the V20G mutation were incapable of stopping the growth of ice crystals and exhibited structural changes, as well as increased conformational flexibility, in the first 3


Lee J.-Y.,Kangwon National University | Lee K.-S.,KBSI | Park Y.,Kangwon National University | Choi H.-M.,Kangwon National University | And 2 more authors.
Journal of the Geological Society of India | Year: 2013

The chemical and isotopic compositions of groundwater and stream water in the Haean basin, Korea, which have been intensively used for agricultural irrigation, were examined. The field parameters and chemical compositions were typical of relatively uncontaminated waters, except for the agricultural impact. The low EC levels indicated that the waters had not experienced any significant geochemical processes such as water-rock interaction and evaporation. The very similar chemical compositions and ionic ratios were also indicative of fast circulation and good hydraulic connection. The oxygen and hydrogen isotopic compositions of most of the samples in wet and dry seasons showed very similar range which indicated a single source for both waters without any significant geochemical alteration. However, in the wet season, evaporation trends were observed in some groundwaters because of inflow of irrigation return flow from a rice paddy field. The isotopes of both waters were affected by the altitude and amount of precipitation. © 2013 Geological Society of India.

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