• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.37.1-37.1
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• 2010

The multi-component olivine cathode material, $LiMn_{1/3}Fe_{1/3}Co_{1/3}PO_4$, was prepared via a novel coprecipitation method of the mixed transition metal oxalate, $Mn_{1/3}Fe_{1/3}Co_{1/3}(C_2O_4){\cdot}2H_2O$. The stoichiometric ratio and distribution of transition metals in the oxalate, therefore, in the olivine product, was affected sensitively by the environments in the coprecipitation process, while they are the important factors in determining the electrochemical property of electrode materials with multiple transition metals. The effect of the pH, atmosphere, temperature, and aging time was investigated thoroughly with respect to the atomic ratio of transition metals, phase purity, and morphology of the mixed transition metal oxalate. The electrochemical activity of each transition metal in the olivine synthesized through this method clearly was enhanced as indicated in the cyclic voltammetry (CV) and galvanostatic charge/discharge measurement. Three distinctive contributions from Mn, Fe, and Co redox couples were detected reversibly in multiple charge and discharge processes. The first discharge capacity at the C/5 rate was $140.5\;mAh\;g^{-1}$ with good cycle retention. The rate capability test showed that the high capacity still is retained even at the 4C and 6C rates with 102 and $81\;mAh\;g^{-1}$, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.553-553
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• 2012

The artificial shells of hard inorganic nanocomposites on individual cells would protect the cells physically and chemically, and control cell division. These emerging properties could be combined with cell-surface functionalizations for applications to cell-based sensors and assays as well as for fundamental studies on single-cell biology. In this work, individual Chlorella cells were encapsulated within a silica/titania nanocomposite shell in a biocompatible fashion that utilized a designed peptide, RKKRKKRKKRKKDDDDDDDD, as a catalytic template for formation of both $SiO_2$ and $TiO_2$ on the cell surface. The cell viability was maintained, and the division of the encapsulated Chlorella cells was controlled. The cell viability was enhanced compared with the $TiO_2$-shell formation. In addition, the incorporation of $TiO_2$ to the shell made it possible to anchor the ligands of interest to the shell via catechol chemistry. All in all, the combination of biological $SiO_2$ and abiolgical $TiO_2$ for the shell formation gave more tunability of the artificial shells compared with the $SiO_2$ or $TiO_2$ shells only.

• The Journal of Korea Robotics Society
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• v.8 no.1
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• pp.51-57
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• 2013

Recently, the number of jellyfish has been rapidly grown because of the global warming, the increase of marine structures, pollution, and etc. The increased jellyfish is a threat to the marine ecosystem and induces a huge damage to fishery industries, seaside power plants, and beach industries. To overcome this problem, a manual jellyfish dissecting device and pump system for jellyfish removal have been developed by researchers. However, the systems need too many human operators and their benefit to cost is not so good. Thus, in this paper, the design, implementation, and experiments of autonomous jellyfish removal robot system, named JEROS, have been presented. The JEROS consists of an unmanned surface vehicle (USV), a device for jellyfish removal, an electrical control system, an autonomous navigation system, and a vision-based jellyfish detection system. The USV was designed as a twin hull-type ship, and a jellyfish removal device consists of a net for gathering jellyfish and a blades-equipped propeller for dissecting jellyfish. The autonomous navigation system starts by generating an efficient path for jellyfish removal when the location of jellyfish is received from a remote server or recognized by a vision system. The location of JEROS is estimated by IMU (Inertial Measurement Unit) and GPS, and jellyfish is eliminated while tracking the path. The performance of the vision-based jellyfish recognition, navigation, and jellyfish removal was demonstrated through field tests in the Masan and Jindong harbors in the southern coast of Korea.

• Genomics & Informatics
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• v.11 no.2
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• pp.76-82
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• 2013

Over the past decade or so, dramatic developments in our ability to experimentally determine the content and function of genomes have taken place. In particular, next-generation sequencing technologies are now inspiring a new understanding of bacterial transcriptomes on a global scale. In bacterial cells, whole-transcriptome studies have not received attention, owing to the general view that bacterial genomes are simple. However, several recent RNA sequencing results are revealing unexpected levels of complexity in bacterial transcriptomes, indicating that the transcribed regions of genomes are much larger and complex than previously anticipated. In particular, these data show a wide array of small RNAs, antisense RNAs, and alternative transcripts. Here, we review how current transcriptomics are now revolutionizing our understanding of the complexity and regulation of bacterial transcriptomes.

• Molecules and Cells
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• v.43 no.3
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• pp.222-227
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• 2020

Inositol polyphosphate multikinase (IPMK) is required for the biosynthesis of inositol phosphates (IPs) through the phosphorylation of multiple IP metabolites such as IP3 and IP4. The biological significance of IPMK's catalytic actions to regulate cellular signaling events such as growth and metabolism has been studied extensively. However, pharmacological reagents that inhibit IPMK have not yet been identified. We employed a structure-based virtual screening of publicly available U.S. Food and Drug Administration-approved drugs and chemicals that identified the antidepressant, vilazodone, as an IPMK inhibitor. Docking simulations and pharmacophore analyses showed that vilazodone has a higher affinity for the ATP-binding catalytic region of IPMK than ATP and we validated that vilazodone inhibits IPMK's IP kinase activities in vitro. The incubation of vilazodone with NIH3T3-L1 fibroblasts reduced cellular levels of IP5 and other highly phosphorylated IPs without influencing IP4 levels. We further found decreased Akt phosphorylation in vilazodone-treated HCT116 cancer cells. These data clearly indicate selective cellular actions of vilazodone against IPMK-dependent catalytic steps in IP metabolism and Akt activation. Collectively, our data demonstrate vilazodone as a method to inhibit cellular IPMK, providing a valuable pharmacological agent to study and target the biological and pathological processes governed by IPMK.

• Journal of Radiation Industry
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• v.9 no.3
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• pp.143-151
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• 2015

A PET-MR system is particularly useful in diagnosing brain diseases. We have developed a prototype positron emission tomography (PET) system which can be inserted into the bore of a whole-body magnetic resonance imaging (MRI) system that enables us to obtain PET and MRI images simultaneously with a reduced cost. Silicon photomultipliers (SiPM) are appropriated as a PET detector at PET/MR system because detectors have a high gain and are insensitive to magnetic fields. Despite of its improved performance compared to that of PMT-based detectors, there is a problem of the photo-peak channel shift which is due to the increase of the temperature inside the ring detector. This problem will occur decreasing sensitivity of the PET and image distortion. In this paper, I quantitative analyze parameters of the KAIST SiPM depending on temperature by experiments. And I designed cooling methods in consideration of the degradation of sensors for correction of the temperature in the PET gantry. According to this research, we expect that distortive images and degradation of the sensitivity will not be occurred with using the above idea to reduce heat even if the PET system operates for a long time.

• Journal of Ginseng Research
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• v.46 no.1
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• pp.79-90
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• 2022

Background: Herbal medicines are popular approaches to capably prevent and treat obesity and its related diseases. Excessive exposure to dietary lipids causes oxidative stress and inflammation, which possibly induces cellular senescence and contribute the damaging effects in brain. The potential roles of selective enhanced ginsenoside in regulating high fat diet (HFD)-induced brain damage remain unknown. Methods: The protection function of Ginsenoside F1-enhanced mixture (SGB121) was evaluated by in vivo and in vitro experiments. Human primary astrocytes and SH-SY5Y cells were treated with palmitic acid conjugated Bovine Serum Albumin, and the effects of SGB121 were determined by MTT and lipid uptake assays. For in vivo tests, C57BL/6J mice were fed with high fat diet for 3 months with or without SGB121 administration. Thereafter, immunohistochemistry, western blot, PCR and ELISA assays were conducted with brain tissues. Results and conclusion: SGB121 selectively suppressed HFD-induced oxidative stress and cellular senescence in brain, and reduced subsequent inflammation responses manifested by abrogated secretion of IL-6, IL-1β and TNFα via NF-κB signaling pathway. Interestingly, SGB121 protects against HFD-induced damage by improving mitophagy and endoplasmic reticulum-stress associated autophagy flux and inhibiting apoptosis. In addition, SGB121 regulates lipid uptake and accumulation by FATP4 and PPARα. SGB121 significantly abates excessively phosphorylated tau protein in the cortex and GFAP activation in corpus callosum. Together, our results suggest that SGB121 is able to favor the resistance of brain to HFD-induced damage, therefore provide explicit evidence of the potential to be a functional food.

• Composites Research
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• v.36 no.6
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• pp.416-421
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• 2023

Multifunctional composite materials capable of both load-carrying and energy functions are promising innovative candidates for the advancement of contemporary technologies owing to their relative feasibility, cost-effectiveness, and optimized performance. Carbon fiber (CF)-based structural batteries utilize the graphitic inherent structure to enable the employment of carbon fibers as electrodes, current collectors, and reinforcement, while the matrix system is an ion-conduction and load transfer medium. Although it is possible to enhance performance through the modification of constituents, there remains a need for a systematic design methodology scheme to streamline the commercialization of structural batteries. In this work, a bi-phasic epoxy-based ionic liquid (IL) modified structural battery electrolyte (SBE) was developed via thermally initiated phase separation. The polymer's morphological, mechanical, and electrochemical characteristics were studied. In addition, the interfacial shear strength (IFSS) between CF/SBE was investigated via microdroplet tests. The results accentuated the significance of considering IFSS and matrix plasticity in designing composite structural batteries. This approach is expected to lay the foundation for realizing smart structures with optimized performance while minimizing the need for extensive trial and error, by paving the way for a streamlined computational design scheme in the future.

• Bulletin of the Korean Mathematical Society
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• v.30 no.2
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• pp.245-250
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• 1993

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.06a
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• pp.629-632
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• 1990