• Journal of the Korean Electrochemical Society
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• v.19 no.3
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• pp.80-86
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• 2016

High Ni content layered oxide materials for the positive electrode in lithium-ion batteries have high specific capacity. However, their poor electrochemical and thermal stability at elevated temperature restrict the practical use. A small amount of $Al_2O_3$ was added to the mixture of transition metal hydroxide and lithium hydroxide. The $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ was simultaneously doped and coated with $Al_2O_3$ during heat-treatment. Electrochemical characteristics of modified $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ were evaluated by the galvanostatic cycling and the LSTA(linear sweep thermmametry) at the constant voltage conditions. The nano-sized $Al_2O_3$ added materials show better cycle performance at elevated temperature than that of micro-sized $Al_2O_3$. As the added amount of nano-$Al_2O_3$ increased, the thermal stability of electrode also enhanced, but the use of 2.5 mol% Al showed the best high temperature performance.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.404-416
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• 2020

Bacteria that are resistant to high temperatures and alkaline environments are essential for the biological repair of damaged concrete. Alkaliphilic and halotolerant Bacillus sp. AK13 was isolated from the rhizosphere of Miscanthus sacchariflorus. Unlike other tested Bacillus species, the AK13 strain grows at pH 13 and withstands 11% (w/v) NaCl. Growth of the AK13 strain at elevated pH without urea promoted calcium carbonate (CaCO₃) formation. Irregular vaterite-like CaCO₃ minerals that were tightly attached to cells were observed using field-emission scanning electron microscopy. Energy-dispersive X-ray spectrometry, confocal laser scanning microscopy, and X-ray diffraction analyses confirmed the presence of CaCO₃ around the cell. Isotope ration mass spectrometry analysis confirmed that the majority of CO₃^2- ions in the CaCO₃ were produced by cellular respiration rather than being derived from atmospheric carbon dioxide. The minerals produced from calcium acetate-added growth medium formed smaller crystals than those formed in calcium lactate-added medium. Strain AK13 appears to heal cracks on mortar specimens when applied as a pelletized spore powder. Alkaliphilic Bacillus sp. AK13 is a promising candidate for self-healing agents in concrete.

• Ocean and Polar Research
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• v.30 no.3
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• pp.215-224
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• 2008

A piston core (MR06-04 PC23A) collected from the northern continental slope in the central Bering Sea has recorded the high-resolution millennial-scale variation of calcium carbonate ($CaCO3$) content during the last 65 kyr. An estimation of the age of the core sediments was carried out by using the lithologic correlation of the deglacial laminated layers with a neighboring core (HLY02023JPC), complementing the last appearance datum of both Lychnocanoma nipponica sakaii (54 kyr) and Amphimelissa setosa (85 kyr). The probable age of core MR06-04 PC23A was approximately younger than 65 kyr. Two distinct events of a significant increase of $CaCO3$ in the deglacial laminated sediments clearly correspond to MWP1A and MWP1B in the Bering Sea (Gorbarenko et al. 2005) and to T1ANP and T1BNP in the North Pacific (Gorbarenko 1996). These pronounced peaks of $CaCO3$ contents result from the elevated carbonate production in the surface water and the subsequent weakened dilution due to terrestrial input, along with an enhanced oxygen minimum zone. The $CaCO3$ contents are low (${\sim}2%$) during the last glacial period mainly because of a low carbonate production caused by an expanded sea-ice cover and an increased dilution by terrigenous particles due to their closer distance to the continent during the sea-level low stand. The occurrence of seven distinct $CaCO3$ peaks in core MR06-04 PC23A is remarkable during MIS 3 and MIS 4, and they most likely correlate to the short-term millennial Dansgaard-Oeschger events.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.195-200
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• 2007

We fabricated thermally-evaporated 10 nm-Ni/70 w-Poly-Si/200 $nm-SiO_2/Si$ and $10nm-Ni_{0.5}Co_{0.5}/70$ nm-Poly-Si/200 $nm-SiO_2/Si$ structures to investigate the microstructure of nickel monosilicide at the elevated temperatures required fur annealing. Silicides underwent rapid anneal at the temperatures of $600{\sim}1100^{\circ}C$ for 40 seconds. Silicides suitable for the salicide process formed on top of the polycrystalline silicon substrate mimicking the gates. A four-point tester was used to investigate the sheet resistances. A transmission electron microscope and an Auger depth profile scope were employed for the determination of cross sectional microstructure and thickness. 20nm thick nickel cobalt composite silicides on polycrystalline silicon showed low resistance up to $900^{\circ}C$, while the conventional nickle silicide showed low resistance below $900^{\circ}C$. Through TEM analysis, we confirmed that the 70nm-thick nickel cobalt composite silicide showed a unique silicon-silicide mixing at the high silicidation temperature of $1000^{\circ}C$. We identified $Ni_3Si_2,\;CoSi_2$ phase at $700^{\circ}C$ using an X-ray diffractometer. Auger depth profile analysis also supports the presence of this mixed microstructure. Our result implies that our newly proposed NiCo composite silicide from NiCo alloy films process may widen the thermal process window for the salicide process and be suitable for nano-thick silicides.

• Journal of Korean Medicine for Obesity Research
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• v.19 no.2
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• pp.89-96
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• 2019

Objectives: We investigated whether membrane free stem cell extract from adipose tissue (MFSCE) has anti-diabetic effect. Methods: To determine glucose uptake effect of MFSCE, we carried out glucose uptake assay in 3T3-L1 adipocytes. The regulatory mechanisms of MFSCE on glucose uptake were examined by Western blot analysis. Results: When MFSCE was treated to adipocytes at the concentration of 0.5, 1, 2.5, and 5 ㎍/mL, 2-deoxyglucose-6-phosphate uptake was elevated approximately 1.8-fold compared to cells not treated with MFSCE. It indicated that MFSCE enhances glucose uptake in 3T3-L1 adipocytes. In addition, MFSCE reduced phosphorylation of insulin receptor substrate-1 at serine 307 and induced Akt and glucose transporter 4 protein expressions that were related to insulin signaling. Furthermore, MFSCE regulated adenosine monophosphate-activated protein kinase (AMPK) pathway by increases of increase phosphorylation of AMPK and acetyl-CoA carboxylase that were related to AMPK pathway. Conclusions: These results indicated that MFSCE promotes glucose uptake via modulation of insulin signaling and AMPK pathway. Therefore, MFSCE could be a promising agent for treatment of diabetes mellitus.

• Clinical and Experimental Vaccine Research
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• v.11 no.2
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• pp.217-221
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• 2022

Lacunar strokes occur when a branch of a large cerebral artery is blocked. The thalamus is often affected, causing uncontrollable motions. A 72-year-old previously healthy man presented with involuntary motions in the right limbs, which were present at rest, and exacerbated during voluntary actions. He had received the first dose of the adenoviral vector-based coronavirus disease 2019 vaccine (ChAdOx1 nCoV-19) 9 days ago. Severe thrombocytopenia and elevated levels of lactate dehydrogenase, ferritin, C-reactive protein, and D-dimer were found, without any evidence of connective tissue disease. Electromyography demonstrated typical choreiform movements, and the brain magnetic resonance imaging indicated a small high signal lesion on the left side of the thalamus. Detection of the immunoglobulin G antibodies against platelet factor 4 in the blood, negative heparin-induced platelet activation (HIPA) test, and positive modified HIPA test confirmed the thalamic stroke due to the vaccine-induced prothrombotic immune thrombocytopenia (VIPIT). He was admitted to the intensive care unit and received nadroparin, sodium ozagrel, edaravone, methylprednisolone, and haloperidol. His hemi-chorea improved gradually over 2 weeks, and he was discharged after 21 days with rehabilitation advice. VIPIT due to the ChAdOx1 nCoV-19 is a novel immune-mediated response that needs clinicians' awareness and further investigations.

• Journal of Bio-Environment Control
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• v.19 no.3
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• pp.123-129
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• 2010

A study on modeling of medium temperature drops of the elevated-bench hydroponic system for strawberry cultivation during low temperature season was conducted. Four different conditions were used for the experiment. These consisted of two kinds of bed types (plant, V), four kinds of medium (rice, perlite, rice hulls80% and peatmoss20%, perlite80% and peatmoss20%), two kinds of mulched bed (mulched, non mulched) and four kinds of greenhouse air temperature (l.5, 3.2, 5.0, $6.7^{\circ}C$), and the results were summarized as follows: Temperature drop of medium in the V-bed was slower than that in the plant bed, showing better insulation effect of V-bed. Temperature drop of medium with mulching on the top of the bed was slower than the case without mulching, as a result, the beneficial effect of temperature drop was appeared in mulched bed. Linear regression of the temperature descent rate and the temperature difference between medium and air showed significant correlation. The regression equation for the Pearlite80% and Peatmoss20% in the V-bed was f(x) = -0.2656 + 0.1345x at the $R^2$ of 0.9269. Using the model, the temperature drop during night can be predicted for the various media at the different depths.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.153-165
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• 2014

Carbon dioxide capture and storage (CCS) technology is recognizing one of method responding the climate change with reduction of carbon dioxide in atmosphere. In Korea, due to its geological characteristics, sub-seabed geological $CO_2$ storage is regarded as more practical approach than on-land storage under the goal of its deployment. However, concerns on potential $CO_2$ leakage and relevant acidification issue in the marine environment can be an important subject in recently increasing sub-seabed geological $CO_2$ storage sites. In the present study effect data from literatures were collected in order to conduct an effect assessment of elevated $CO_2$ levels in marine environments using a species sensitivity distribution (SSD) various marine organisms such as microbe, crustacean, echinoderm, mollusc and fish. Results from literatures using domestic species were compared to those from foreign literatures to evaluate the reliability of the effect levels of each biological group and end-point. Ecological effect guidelines through estimating level of pH variation (${\delta}pH$) to adversely affect 5 and 50% of tested organisms, HC5 and HC50, were determined using SSD of marine organisms exposed to the $CO_2$-induced acidification. Estimated HC5 as ${\delta}pH$ of 0.137 can be used as only interim quality guideline possibly with adequate assessment factor. In the future, the current interim guideline as HC5 of ${\delta}pH$ in this study will look forward to compensate with supplement of ecotoxicological data reflecting various trophic levels and indigenous species.

• Journal of Life Science
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• v.28 no.6
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• pp.648-655
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• 2018

Enhancement mechanistic actions of testosterone (TS) productions in mouse Leydig TM3 cells by the eritadenine (EA) and/or the Agaricus blazei mycelial liquid culture extract (ABMLCE). Productions of TS in TM3 cells were investigated in normal and oxidative-stressed culture conditions. In the normal culture condition, TM3 cells grown in a Dulbecco's Modified Eagle's Medium (DMEM) were treated with EA (0~100 ppm) and ABMLCE (10 ppm) + EA (0~50 ppm) for 24 hr, and in the oxidative-stressed culture condition, the cells grown in DMEM containing $50{\mu}M$ $H_2O_2$ to induce oxidative stress for 4 h were treated with the same as those in the normal culture condition. TS content, $3{\beta}$-hydroxysteroid dehydrogenase 2 (HSD3B2) enzyme activity, $5{\alpha}$-reductase 2 ($5{\alpha}-R2$) enzyme activity, and free-radical nitric oxide (NO) content in the culture media were measured using their corresponding assay kits. EA, ABMLCE, and ABMLCE + EA significantly, p<0.05, enhanced TS productions in both cultural conditions, relative to control treatment. The activity of the HSD3B2 enzyme, which is involved in the production of precursors for TS production, was elevated by EA, ABMLCE, and ABMLCE + EA treatments in both culture conditions. The activity of the $5{\alpha}-R2$ enzyme, which converts TS to dihydroxytestosterone (DHT), was not significantly affected in either culture condition by EA, ABMLCE, or ABMLCE + EA treatments. The treatments included reduced NO content. These results indicate that EA, ABMLCE, and EA + ABMLCE treatments elevated TS in TM3 cells via the enhancements of HSD3B2 activity and the reduction of NO production, and also imply that EA and ABMLCE or EA + ABMLCE could be useful materials for the production of TS in humans.

• Food Science and Preservation
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• v.22 no.6
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• pp.804-810
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• 2015

Salvia miltiorrhiza has been used for treating heart and liver disease. In the present study, the influences of temperature on photosynthetical capacity of S. miltiorrhiza under controlled cultivation environment using growth chamber were investigated because of providing information about growth and secondary metabolite synthesis. And effect of harvesting time on growth properties and constituents such as salvianolic acid B, cryptotanshinone, tanshinone I, tanshinone IIA were evaluated. Maximum photosynthesis rate ($5.102{\mu}mol\;CO2/m2/s$) and net apparent quantum yield ($0.147{\mu}mol\;CO2/m2/s$), stomatal conductance (0.035 mmol/m2/s) and water use efficiency ($7.108{\mu}mol\;CO2/mmol\;H2O$) was highest at $20^{\circ}C$. Results of chlorophyll fluorescence showed that elevated temperature had contributed to reduce a quantum yield and electron flux in photosystem. This result demonstrated that favorable temperature condition was determined at $20^{\circ}C$. Contents of salvianolic acid B, cryptotanshinone, tanshinone I and tanshinone IIA was highest in root sample harvested at 20 March, whereas growth and yield of S. miltiorrhiza had no significant differences with harvesting time. Therefore, this study shows that temperature play an important role in photosynthetic activity and harvesting time have influence upon accumulation of constituents in root of S. miltiorrhiza.