• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.211-219
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• 2021

Alopecia is a distressing condition caused by the dysregulation of anagen, catagen, and telogen in the hair cycle. Dermal papilla cells (DPCs) regulate the hair cycle and play important roles in hair growth and regeneration. Myristoleic acid (MA) increases Wnt reporter activity in DPCs. However, the action mechanisms of MA on the stimulation of anagen signaling in DPCs is not known. In this study, we evaluated the effects of MA on anagen-activating signaling pathways in DPCs. MA significantly increased DPC proliferation and stimulated the G2/M phase, accompanied by increasing cyclin A, Cdc2, and cyclin B1. To elucidate the mechanism by which MA promotes DPC proliferation, we evaluated the effect of MA on autophagy and intracellular pathways. MA induced autophagosome formation by decreasing the levels of the phospho-mammalian target of rapamycin (phospho-mTOR) and increasing autophagy-related 7 (Atg7) and microtubule-associated protein 1A/1B-light chain 3II (LC3II). MA also increased the phosphorylation levels of Wnt/β-catenin proteins, such as GSK3β (Ser9) and β-catenin (Ser552 and Ser675). Treatment with XAV939, an inhibitor of the Wnt/β-catenin pathway, attenuated the MA-induced increase in β-catenin nuclear translocation. Moreover, XAV939 reduced MA-induced effects on cell cycle progression, autophagy, and DPC proliferation. On the other hand, MA increased the levels of phospho (Thr202/Tyr204)-extracellular signal regulated kinases (ERK). MA-induced ERK phosphorylation led to changes in the expression levels of Cdc2, Atg7 and LC3II, as well as DPC proliferation. Our results suggest that MA promotes anagen signaling via autophagy and cell cycle progression by activating the Wnt/β-catenin and ERK pathways in DPCs.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.52-58
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• 2020

Electrochemical characterization and thermal stability were investigated for MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ cathode. The ratio of MgF₂ was controlled by 0.5, 1, 3 wt%. Cyclic voltammetry, charge-discharge profiles, rate capability, cycle life were measured for electrochemical properties. DSC analysis was measured for thermal stability. The first discharge capacities of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ were decreased at 0.1C-rate compared to pristine LiNi_0.8Co_0.15Al_0.05O₂. But the rate capability and cycle life of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ were improved at 2C-rate. In DSC analysis result, the exothermic temperature of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ was increased and peak height was decreased.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.119-127
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• 2014

This study aims to determine whether or not the input output life cycle assessment (I-O LCA) model can be used to assess the carbon dioxide (CO2) emission of buildings in initial planning phase. To ensure this end, this study proposed I-O LCA model which is the simplified LCA model and Hybrid LCA model which is the detailed LCA model, and then assessed and compared the CO2 emission of six case projects (three apartment complexes and three educational facilities) using the two LCA model. The results of the case study showed that the CO2 emissions assessed by the I-O LCA is significantly similar to the CO2 emission assessed by the Hybrid LCA model. The similarity of results from both LCA models was 78.2-86.3% in apartment complexes and 59.9-84.8% in educational facilities. However, the CO2 emissions from I-O LCA model were smaller than the CO2 emissions from Hybrid LCA model in case study. Nevertheless, the case study showed that the I-O LCA model was capable of assessing the CO2 emission of buildings quite appropriately although the I-O LCA model is the simplified LCA model which considers only the construction cost. The I-O LCA model is expected to be a useful tool for assessing the CO2 emission of buildings in initial planning phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.25-28
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• 1998

Lithiated cobalt and nickel oxides are becoming very attractive as active cathode materials for secondary lithium ion secondary battery. $LiCoO_2$ is easily synthesized from lithium cobalt salts, but has a relatively high oxidizing potential on charge. LiNiOz is synthesized by a more complex procedure and its nonstoichiometry significantly degraded the charge-discharge characteristics. But $LiNiO_2$ has a lower charge potential which increases the system stability. Lithiated cobalt and nickel oxides are iso-structure which make the preparation of solid solutions of $LiNi_{1-x}Co_xO_2$ for O$LiCoO_2 and LiNiO_2$ electrode. The aim of the presentb paper is to study the electrochemical behaviour, as weU as the possibilities for practical application of layered Iithiated nickel oxide stabilized by $Co^{3+}$ substitution as active cathode materials in lithium ion secondary battery.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.2
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• pp.173-182
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• 2012

Effects of temperature, pressure, and gas residence time on methane combustion characteristics of mass produced oxygen carrier particle (OCN706-1100) were investigated in a pressurized fluidized bed reactor using methane and air as reactants for reduction and oxidation, respectively. The oxygen carrier showed high fuel conversion, high $CO_2$ selectivity, and low CO concentration at reduction condition and very low NO emission at oxidation condition. Moreover OCN706-1100 particle showed good regeneration ability during successive reduction-oxidation cyclic tests up to the 10th cycle. Fuel conversion and $CO_2$ selectivity decreased and CO emission increased as temperature increased. These results can be explained by trend of calculated equilibrium CO concentration. However, $CO_2$ selectivity increased as pressure increased and fuel conversion increased as gas residence time increased.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.146-153
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• 2009

The performance characteristics of heat exchangers which consist of a gas cooler, an evaporator and an internal heat exchanger have been investigated at various operating conditions of $CO_2$ air conditioning system by experiments. The heat exchangers were designed for use in the vehicle $CO_2$ air conditioning system, when considering the characteristics of heat transfer and high pressure as $CO_2$ refrigerant. This paper studied the performance of heat exchangers at various compressor speeds and expansion valve openings, and quantified the heat transfer rates and pressure drops. Heat transfer rates at the gas cooler and the evaporator were 6.9 kW and 5.2 kW, respectively, when the compressor speed was 4000 rpm and refrigerant vapor quality at the evaporator outlet was 0.98. Therefore, this paper carried out that the heat exchangers were analyzed to achieve superior performance for the vehicle transcritical $CO_2$ cycle.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.103-105
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• 2015

The 22 m diameter Mopra telescope in Australia is being used to undertake an improved survey of the CO J = 1-0 line at 3mm along the 4th quadrant of the Galaxy, achieving an order of magnitude better spatial and spectral resolution (i.e. 0.6 and 0.1 km/s) than the Dame et al. (2001) survey that is publically available for the Southern Galactic plane. Furthermore, the Mopra CO survey includes the four principal isotopologues of the CO molecule (i.e. $^{12}CO$, $^{13}CO$, $C^{18}O$ and $C^{17}O$). The survey makes use of an 8 GHz-wide spectrometer and a fast mode of on-the-fly mapping developed for the Mopra telescope, where the cycle time has been reduced to just 1/4 of a second. 38 square degrees of the Galaxy, from $l=306-344^{\circ}$, $b=0{\pm}5^{\circ}$ have currently been surveyed, together with additional 9 sq. deg. regions around the Carina complex and the Central Molecular Zone. We present new results from the survey (see also Burton et al., 2013, 2014). The Mopra CO data are being made publically available as they are published; for the latest release see the project website at www.phys.unsw.edu.au/mopraco.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.10-11
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• 2019

The purpose of this study is to validate the environmental performance of the 'eco-friendly lightweight form' in the construction process. Unlike existing euro form and aluminum form, the proposed form does not require form oil during the process of concrete casting and is lightweight because it is made of engineering plastic. Therefore, eco-friendly lightweight form will reduce the $CO_2$ emissions in the construction process. To verify the hypothesis, the study compared existing forms and eco-friendly light weight form's $CO_2$ emissions in each stage in construction process when using 1,000 forms and 100 times from the LCI(Life Cycle Inventory) data. The total $CO_2$ emissions of the eco-friendly light weight form were 30,487kg $CO_2$, which equated to about 58% and 20% less emissions than the euroform and aluminum form. The result of the study verified that the eco-friendly lightweight form was effectively reduced $CO_2$ emission in the construction process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.11
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• pp.851-858
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• 2006

[ $CO_2$ ] and propane mixtures, which are environmentally benign, nontoxic, low in price, and compatible with materials and lubricants, were considered as promising alternative refrigerants. A fully instrumented air-conditioning system was developed for a precise performance evaluation of pure $CO_2$ and $CO_2/propane$ mixtures. In this paper, the effect of the charging amount and circulation concentration on the cooling performance of the system using $CO_2$ and propane mixtures was tested and discussed. Pure $CO_2$ and 85/15, 75/25 and 60/40 binary blends by the charged mass percentage of $CO_2/propane$ were selected as working fluids. An optimum charging amount was proposed as a parameter instead of the degree of subcooling, which can not be well defined in the transcritical cycle, to properly compare the performance between the transcritical and subcritical cycles.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.324-330
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• 2019

Petal-like nickel cobaltite ($NiCo_2O_4$)/reduced graphene oxide (rGO) composites with different $rGO-to-NiCo_2O_4$ weight ratios were synthesized using a simple hydrothermal method and subsequent thermal treatment. In the $NiCo_2O_4/rGO$ composite, the $NiCo_2O_4$ 3-dimensional nanomaterials contributed to the improvement of electrochemical properties of the final composite material by preventing the restacking of the rGO sheet and securing ion movement passages. The composite structure was examined by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Fourier-transform infrared (FT-IR) spectroscopy. The FE-SEM and TEM images showed that petal-like $NiCo_2O_4$ was supported on the rGO surface. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) were used for the electrochemical analysis of composites. Among the prepared composites, $0.075g\;rGO/NiCo_2O_4$ composite showed the highest specific capacitance of $1,755Fg^{-1}$ at a current density of $2Ag^{-1}$. The cycle performance and rate capability of the composite material were higher than those of using the single $NiCo_2O_4$ material. These nano-structured composites could be regarded as valuable electrode materials for supercapacitors that require superior performance.