192 research outputs found

    The Ministry of National Defence in South Korea: Military dominance despite civilian supremacy?

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    South Korea's transition from military-controlled authoritarianism to consolidated civilian-dominated democracy is widely considered a success story. However, civilians' roles within the MND remain severely limited due to the institutional design of the MND. A decentralised structure emerged in the MND, delegating policy decision-making in critical areas to professional soldiers. Data analysis on 1,060 employees in 21 MND departments shows a clear cut between the military domain and the civilian domain within the MND, which enabled the military to thwart 30 years of civilian efforts to reform the military structure without challenging the principle of civilian supremacy

    Challenges in Design and Fabrication of Flexible/Stretchable Carbon- and Textile-Based Wearable Sensors for Health Monitoring: A Critical Review

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    To demonstrate the wearable flexible/stretchable health-monitoring sensor, it is necessary to develop advanced functional materials and fabrication technologies. Among the various developed materials and fabrication processes for wearable sensors, carbon-based materials and textile-based configurations are considered as promising approaches due to their outstanding characteristics such as high conductivity, lightweight, high mechanical properties, wearability, and biocompatibility. Despite these advantages, in order to realize practical wearable applications, electrical and mechanical performances such as sensitivity, stability, and long-term use are still not satisfied. Accordingly, in this review, we describe recent advances in process technologies to fabricate advanced carbon-based materials and textile-based sensors, followed by their applications such as human activity and electrophysiological sensors. Furthermore, we discuss the remaining challenges for both carbon- and textile-based wearable sensors and then suggest effective strategies to realize the wearable sensors in health monitoring

    Paper-Based Flexible Electrode Using Chemically-Modified Graphene and Functionalized Multiwalled Carbon Nanotube Composites for Electrophysiological Signal Sensing

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    Flexible paper-based physiological sensor electrodes were developed using chemically-modified graphene (CG) and carboxylic-functionalized multiwalled carbon nanotube composites (f@MWCNTs). A solvothermal process with additional treatment was conducted to synthesize CG and f@MWCNTs to make CG-f@MWCNT composites. The composite was sonicated in an appropriate solvent to make a uniform suspension, and then it was drop cast on a nylon membrane in a vacuum filter. A number of batches (0%~35% f@MWCNTs) were prepared to investigate the performance of the physical characteristics. The 25% f@MWCNT-loaded composite showed the best adhesion on the paper substrate. The surface topography and chemical bonding of the proposed CG-f@MWCNT electrodes were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The average sheet resistance of the 25% CG-f@MWCNT electrode was determined to be 75 Ω/⬜ , and it showed a skin contact impedance of 45.12 kΩ at 100 Hz. Electrocardiogram (ECG) signals were recorded from the chest and fingertips of healthy adults using the proposed electrodes. The CG-f@MWCNT electrodes demonstrated comfortability and a high sensitivity for electrocardiogram signal detection

    Localizome: a server for identifying transmembrane topologies and TM helices of eukaryotic proteins utilizing domain information

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    The Localizome server predicts the transmembrane (TM) helix number and TM topology of a user-supplied eukaryotic protein and presents the result as an intuitive graphic representation. It utilizes hmmpfam to detect the presence of Pfam domains and a prediction algorithm, Phobius, to predict the TM helices. The results are combined and checked against the TM topology rules stored in a protein domain database called LocaloDom. LocaloDom is a curated database that contains TM topologies and TM helix numbers of known protein domains. It was constructed from Pfam domains combined with Swiss-Prot annotations and Phobius predictions. The Localizome server corrects the combined results of the user sequence to conform to the rules stored in LocaloDom. Compared with other programs, this server showed the highest accuracy for TM topology prediction: for soluble proteins, the accuracy and coverage were 99 and 75%, respectively, while for TM protein domain regions, they were 96 and 68%, respectively. With a graphical representation of TM topology and TM helix positions with the domain units, the Localizome server is a highly accurate and comprehensive information source for subcellular localization for soluble proteins as well as membrane proteins. The Localizome server can be found at

    Using the Galileo Solid-State Imaging Instrument as a Sensor of Jovian Energetic Electrons

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    We quantitatively describe the Jovian energetic electron environment using the Solid State Imager (SSI) on the Galileo spacecraft. We post-process raw SSI images by removing the target object and dark current to obtain frames only with the radiation contribution. The camera settings (gain state, filter, etc.) are used to compute the energy deposited in each pixel, which corresponds to the intensity of the observed radiation hits (the actual measurements are expressed with the digital number (DN), from which the energy deposited can be computed). Histograms of the number of pixels versus energy deposited by incident particles from processed SSI images are compared with the results from 3D Monte Carlo transport simulations of the SSI using Geant4. We use Geant4 to simulate the response of the SSI instrument to mono-energetic electron environments from 1 to 100 MeV. We fit the modeled instrument response to the SSI data using a linear combination of the simulated mono-energetic histograms to match the SSI observations. We then estimate the spectra of the energetic electron environment at Jupiter, or we estimate the integral flux when there is lower confidence in the spectra fits. We validate the SSI results by comparing the environment predictions to the observations from the Energetic Particle Detector (EPD) on the Galileo spacecraft, examining the electron differential fluxes from 10’s of keV to 11 MeV. For higher energies (up to 31.0 MeV), we compare our findings with the NASA GIRE model, which is based on measurements from the Pioneer spacecraft. This approach could be applied to other sets of imaging data in energetic electron environments, such as from star trackers in geostationary Earth orbits.Funding for A. Carlton’s work is provided by a NASA Space Technology Research Fellowship (NNX16AM74H)

    Sorbus alnifolia protects dopaminergic neurodegeneration in Caenorhabditis elegans

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    Context: The twigs of Sorbus alnifolia (Sieb. et Zucc.) K. Koch (Rosaceae) have been used to treat neuro- logical disorders as a traditional medicine in Korea. However, there are limited data describing the efficacy of S. alnifolia in Parkinson’s disease (PD). Objective: This study was conducted to identify the protective effects of the methanol extracts of S. alnifolia (MESA) on the dopaminergic (DA) neurodegeneration in Caenorhabditis elegans. Materials and methods: To test the neuroprotective action of MESA, viability assay was performed after 48 h exposure to 1-methyl-4-phenylpyridine (MMPþ) in PC12 cells and C. elegans (400 lM and 2 mM of MMPþ, respectively). Fluorescence intensity was quantified using transgenic mutants such as BZ555 (Pdat-1::GFP) and and UA57 (Pdat-1::GFP and Pdat-1::CAT-2) to determine MESA’s effects on DA neurode- generation in C. elegans. Aggregation of a-synuclein was observed using NL5901 strain (unc-54p::a- synuclein::YFP). MESA’s protective effects on the DA neuronal functions were examined by food-sensing assay. Lifespan assay was conducted to test the effects of MESA on the longevity. Results: MESA restored MPPþ-induced loss of viability in both PC12 cells and C. elegans (85.8% and 54.9%, respectively). In C. elegans, MESA provided protection against chemically and genetically-induced DA neurodegeneration, respectively. Moreover, food-sensing functions were increased 58.4% by MESA in the DA neuron degraded worms. MESA also prolonged the average lifespan by 25.6%. However, MESA failed to alter a-synuclein aggregation. Discussion and conclusions: These results revealed that MESA protects DA neurodegeneration and recov- ers diminished DA neuronal functions, thereby can be a valuable candidate for the treatment of PD

    The Effect of Differential Modulation of the N-methyl-D-aspartate Receptor on Growth and intracellular Calcium Ion Concentration in Normal Human Oral Keratinocytes

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    The purpose of this study was to examine the interaction between the agents [N-methyl-D-aspartate (NMDA), arachidonic acid (AA), and Nitric Oxide Synthase Inhibitor (NOS-I)] and cultured normal human oral keratinocytes (NHOK) in order to elucidate the mechanisms by which epithelial growth and regeneration are regulated. We also examined whether AA and NOS-I could protect NHOK from glutamate cytotoxicity and the change of intracellular calcium ion concentration. NHOK were obtained from gingival tissue of 20 individuals aged 20 to 29, and third passage (P3) cells were used for this study. Cell viability was measured by the MTT assay and DNA synthesis by the BrdU assay. The microscopic features of NHOK were observed and changes in intracellular calcium ion concentration were measured. NMDA and NNA induced an initial increase in cell number. Low concentration of AA induced an increase in cell number while high concentrations of AA induced a decrease in cell number. The decrease in cell number induced by NMDA at the seventh day was abolished by the addition of low concentrations of AA or NOS inhibitors. Low concentrations of AA or NMDA with high concentrations of AA significantly increased the DNA synthesis rate at four hours. NMDA and AA both induced an increase in intracellular calcium ion concentration, and AA enhanced NMDA-induced intracellular calcium ion in a concentration-dependent manner. NMDA-induced NHOK death was associated with intracellular calcium ion change and the promotion of cell differentiation. Low concentrations of AA protected NHOK cells from NMDA-induced death.

    Differentially Expressed Potassium Channels Are Associated with Function of Human Effector Memory CD8+T cells

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    The voltage-gated potassium channel, Kv1.3, and the Ca2+-activated potassium channel, KCa3.1, regulate membrane potentials in T cells, thereby controlling T cell activation and cytokine production. However, little is known about the expression and function of potassium channels in human effector memory ( EM) CD8+ T cells that can be further divided into functionally distinct subsets based on the expression of the interleukin ( IL)-7 receptor alpha ( IL-7R alpha) chain. Herein, we investigated the functional expression and roles of Kv1.3 and KCa3.1 in EM CD8+ T cells that express high or low levels of the IL-7 receptor alpha chain ( IL-7R alpha(high) and IL-7R alpha(low), respectively). In contrast to the significant activity of Kv1.3 and KCa3.1 in IL-7Rahigh EM CD8+ T cells, IL-7Ralow EM CD8+ T cells showed lower expression of Kv1.3 and insignificant expression of KCa3.1. Kv1.3 was involved in the modulation of cell proliferation and IL-2 production, whereas KCa3.1 affected the motility of EM CD8+ T cells. The lower motility of IL-7Ralow EM CD8+ T cells was demonstrated using transendothelial migration and motility assays with intercellular adhesion molecule 1-and/or chemokine stromal cell-derived factor-1 alpha-coated surfaces. Consistent with the lower migration property, IL-7Ralow EM CD8+ T cells were found less frequently in human skin. Stimulating IL-7Ralow EM CD8+ T cells with IL-2 or IL-15 increased their motility and recovery of KCa3.1 activity. Our findings demonstrate that Kv1.3 and KCa3.1 are differentially involved in the functions of EM CD8+ T cells. The weak expression of potassium channels in IL-7Ralow EM CD8+ T cells can be revived by stimulation with IL-2 or IL-15, which restores the associated functions. This study suggests that IL-7Rahigh EM CD8+ T cells with functional potassium channels may serve as a reservoir for effector CD8+ T cells during peripheral inflammation.112Ysciescopu
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