• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.43-50
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• 2008

Ceramides, a constituent of stratum corneum lipids, play a crucial role in the formation and maintenance of the epidermal permeability barrier. As in many other skin disorders, atopic dermatitis and psoriasis show decrease and transformation of the ceramides. The application of ceramide has been demonstrated to be efficient in the repair of these skin disorders. Nevertheless, natural ceramides are still too expensive and small in quantity to be used as a cosmetic ingredient. Although a lot of pseudo-ceramides have been developed and on the market until now, those pseudo-ceramides did not fully meet the consumer's needs, therefore, there is still a demand for a novel pseudo-ceramides. We synthesized a novel pseudo-ceramide BPC-16 from 2-(2-amino-ethylamino)-ethanol(AEEA), which was characterized by structures having both amide bonds and hydroxyl groups as hydrophilic units, as well as two long alkyl chains. We formulated emulsion with BPC-16, cholesterol, stearic acid, and other components to make an emulsion. These emulsion showed a typical optical anisotropy on cross-polarized microscopy. This 'Maltese cross' appearance is a characteristic figure observed in concentric lamellar emulsion under cross-polarized microscopy. In cytotoxicity assay using MTT in monolayer and three dimension(3D) cell culture, a BPC-16 showed only negligible cytotoxicity up to the effective concentration for barrier repair and moisturization(less than 10 mM). In the measurement of TEWL, this BPC-16 showed significant recovery of water-retaining properties when it was topically applied to either SDS-induced dry skin or normal skin compared to that of base cream. This novel pseudo-ceramide BPC-16 showed as effective in skin barrier repair and moisturization as natural ceramides.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.769-777
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• 2017

To research the effects of marigold extract, which is used mixed with calendula extract, on collagen growth and MMP-1 expression in human fibroblast, we measured cytotoxicity, collagen growth and MMP-1 expression by using HDF cells. The result of measurement showed over 80% cell survival rate in $5{\sim}100{\mu}g/mL$ concentration of marigold extract and calendula extract for HDF cells, which indicates there is no cytotoxicity. The result of measuring collagen synthetic abilities showed both types of extract had collagen synthetic ability increase dose dependently, by 25% in $100{\mu}g/mL$ concentration of marigold extract, and by 7% in $100{\mu}g/mL$ concentration of calendula extract. The result of experimenting the effect on MMP-1 expression showed that both types of extract suppress MMP-1 expression. The result of observing phosphorylation of p-JNK and p-ERK, which are known to be involved with MMP-1 expression, revealed that marigold extract effectively suppresses MMP-1 expression through signaling pathway of p-JNK and p-ERK. The above results confirm the wrinkle improvement effect of marigold extract, and furthermore, it can be used as a cosmetic ingredient for anti-aging.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.75-80
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• 2019

Silicon solar cells have been widely used as a most promising renewable energy source due to eco-friendliness and high efficiency. As modules of silicon solar cells are connected in series for a practical electricity generation, a large voltage of 500-1,500 V is applied to the modules inevitably. Potential-induced degradation (PID), a deterioration of the efficiency and maximum power output by the continuously applied high voltage between the module frames and solar cells, has been regarded as the major cause that reduces the lifetime of silicon solar cells. In particular, the migration of the $Na^+$ ions from the front glass into Si through the anti-reflection coating and the accumulation of $Na^+$ ions at stacking faults inside Si have been reported as the reason of PID. In this research, the thickness effect of $SiO_x$ layer that can block the migration of $Na^+$ ions on the reduction of PID is investigated as it is incorporated between anti-reflection coating and p-n junction in p-type PERC solar cells. From the measurement of shunt resistance, efficiency, and maximum power output after the continuous application of 1,000 V for 96 hours, it is revealed that the thickness of $SiO_x$ layer should be larger than 7-8 nm to reduce PID effectively.

• Ceramist
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• v.21 no.4
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• pp.378-387
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• 2018

The optimal fabrication conditions for $Gd_{0.1}Ce_{0.9}O_{2-{\delta}}$(GDC) buffer layer and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF) cathode on 1mol% $CeO_2-10mol%\;Sc_2O_3$ stabilized $ZrO_2$ (CeScSZ) electrolyte were investigated for application of IT-SOFCs. GDC buffer layer was used in order to prevent undesired chemical reactions between LSCF and CeScSZ. These experiments were carried out with $5{\times}5cm^2$ anode supported unit cells to investigate the tendencies of electrochemical performance, Microstructure development and interface reaction between LSCF/GDC/CeScSZ along with the variations of GDC buffer layer thickness, sintering temperatures of GDC and LSCF were checked, respectively. Electrochemical performance was analyzed by DC current-voltage measurement and AC impedance spectroscopy. Microstructure and interface reaction were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Although the interfacial reaction between these materials could not be perfectly inhibited, We found that the cell, in which $6{\mu}m$ GDC interlayer sintered at $1200^{\circ}C$ and LSCF sintered at $1000^{\circ}C$ were applied, showed good interfacial adhesions and effective suppression of Sr, thereby resulting in fairly good performance with power density of $0.71W/cm^2$ at $800^{\circ}C$ and 0.7V.

• Polymer(Korea)
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• v.32 no.5
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• pp.403-408
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• 2008

Keratin is the major structural fibrous protein providing outer covering such as wool, hair, and nail. Keratin is useful as natural protein. We developed the keratin loaded poly(L-lactide-co-glycolide) (PLGA) scaffolds (keratin/PLGA) for the possibility of the application of the tissue engineering using bone marrow mesenchymal (BMSCs). Keratin/PLGA (contents 0%, 10%, 20% and 50% of PLGA weight) scaffolds were prepared by solvent casting/salt leaching method. We characterized porosity, wettability, and water uptake ability, DSC of keratin/PLGA scaffold. We seeded BMSCs isolated from the femurs of rat into the inner core of the hybrid scaffold. Celluar viability were assayed by 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyl-tetrazolium bromide (MTT) test. We confirmed that keratin/PLGA scaffold is hydrophilic by wettability, and water uptake ability measurement results. In MTT assay results, cell viability in scaffolds impregnated 10 and 20 wt% of keratin were higher than other scaffolds. In conclusion, we suggest that keratin/PLGA scaffold may be useful to tissue engineering using BMSCs.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.761-767
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• 2021

Strawberries fermented with Acetobacter pasteurianus SRCM60009 were prepared, and the quality characteristics and physiological activity were measured. As the fermentation period increased, viable cell counts increased, pH decreased, and total acidity increased from 1.09% to 4.20%. The organic acid content of strawberry through acetic acid fermentation was confirmed in the following order: acetic acid, succinic acid, citric acid, and lactic acid. Measurement of α-glucosidase and pancreatic lipase inhibitory activities and angiotensin converting enzyme inhibitory activity showed significantly increased physiological activity owing to fermentation. The use of strawberry vinegar as a functional material was confirmed by measuring the anti-diabetic, anti-obesity, and anti-hypertensive physiological activities through acetic acid fermentation of strawberry. Thus, fermented strawberry vinegar can be used as a functional material in vinegar and other foods.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.142-149
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• 2019

Purpose: The purpose of this study is to investigate the changes of osteoclast differentiation inhibition according to the period of precipitation when titanium disks were immersed in Modified simulated body fluid (mSBF). Materials and methods: Titanium alloy (Ti grade III) disks with machined surfaces and anodized surfaces were immersed in distilled water and mSBF, respectively. The immersion periods were 7 days, 14 days, 21 days and 28 days, and the control group was immersed in distilled water for each period. RAW 264.7 cells capable of differentiating into osteoclasts were used to measure the number of adherent cells, the measurement of TRAP activity, and the expression pattern of NFATc1 by western blotting. Results: The degree of inhibition of osteoclast differentiation was found to be statistically significant when the disks were immersed in mSBF for more than 14 days on both machined surfaces and anodized surfaces. There was no correlation between immersion time and cell attachment. When the disks were immersed for more than 14 days, TRAP activity was decreased and NFATc1 expression was inhibited. Futhermore, the decrease in TRAP activity and the inhibition of NFATc1 expression remained unchanged. Conclusion: Immersion of titanium disks in mSBF for more than 14 days can prevent RAW 264.7 cells from differentiating into osteoclasts. Inhibition activity does not change even if the immersion period is for more than 14 days.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.507-516
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• 2018

The closed chamber method, which is one of the most commonly used method for measuring greenhouse gases produced in rice paddy fields, has limitations in measuring dynamic $CH_4$ flux with spatio-temporal constrains. In order to deal with the limitation of the closed chamber method, some studies based on open-path of eddy covariance method have been actively conducted recently. The aim of this study was to compare the $CH_4$ fluxes measured by open-path and closed chamber method in the paddy rice fields. The open-path, one of the gas ($CO_2$, $CH_4$ etc.) analysis methods, is technology where a laser beam is emitted from the source passes through the open cell, reflecting multiple times from the two mirrors, and then detecting. The $CH_4$ emission patterns by these two methods during rice cultivation season were similar, but the total $CH_4$ emission measured by open-path method were 31% less than of the amount measured by closed chamber. The reason for the difference in $CH_4$ emission was due to overestimation by closed chamber and underestimation by open-path. The closed chamber method can overestimate $CH_4$ emissions due to environmental changes caused by high temperature and light interruption by acrylic partition in chamber. On the other hand, the open-path method for eddy covariance can underestimate its emission because it assumes density fluctuations and horizontal homogeneous terrain negligible However, comparing $CH_4$ fluxes at the same sampling time (AM 10:30-11:00, 30-min fluxes) showed good agreements ($r^2=0.9064$). The open-path measurement technique is expected to be a good way to compensate for the disadvantage of the closed chamber method because it can monitor dynamic $CH_4$ fluctuation even if data loss is taken into account.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.191-198
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• 2019

H-NS binds to promoter DNA and works as a general transcription silencer. DicA protein, by binding to the promoter DNA of dicA, activates dicA expression and at the same time inhibits expression of dicF and dicB, thus, exerting cell division control in Escherichia coli. H-NS complexed with a nucleoid protein Cnu was known to be involved in dicA expression. However, the exact nature of H-NS binding to dicA promoter DNA and the consequences of H-NS binding in expression of dicA is not clear. In this study, we explored the DNA binding activity of H-NS on the promoter DNA of dicA and found that H-NS binding occurs exclusively to the dicA promoter DNA. We never observed, however, H-NS binding at the vicinity of the dicA promoter. Temperature dependent oligomerization of H-NS was observed during DNA binding and the Cnu protein enhances the oligomerization process of H-NS binding. In vivo measurement of dicA expression in an hns deleted strain showed that dicA expression increased. These results demonstrated that H-NS binds specifically to dicA promoter DNA and functions as a transcription silencer.

• Korean Journal of Pharmacognosy
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• v.50 no.1
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• pp.11-17
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• 2019

Cassia tora L. have been used as a folk medicine in Korea. This study investigated anti-inflammatory effect of aurantio-obtusin isolated from C. tora. We isolated aurantio-obtusin from 50% ethanol extracts of C. tora L. We investigated the anti-inflammatory effects of aurantio-obtusin on the lipopolysaccharide (LPS)-stimulated inflammatory response in murine macrophage cell line (Raw 264.7). To investigate the cytotoxicity of aurantio-obtusin on RAW 264.7 cells, MTS assay was performed. RAW 264.7 cells were treated with aurantio-obtusin at different concentrations (12.5, 25, 50, $100{\mu}M$) for 30 h. The result showed that aurantio-obtusin had no cytotoxic effect in a concentration range of $12.5-100{\mu}M$. To determine the effect of aurantio-obtusin on LPS-induced NO production, the NO concentration measurement was performed. RAW 264.7 cells were treated with aurantio-obtusin at 12.5, 25, 50 and $100{\mu}M$ for 24 h, and the results showed that the NO production of aurantio-obtusin-treated cells compared to LPS alone treated group was significantly decreased in a dose-dependent manner. Pretreatment of aurantio-obtusin inhibited LPS-induced NO production in a dose-dependent manner. To find out inhibitory mechanisms of aurantio-obtusin on inflammatory mediators, we examined the $PGE_2$ pathways. As a result, $PGE_2$ were decreased in a dose-dependent manner by aurantio-obtusin. The release of interleukin-$1{\beta}$ (IL-$1{\beta}$) and IL-6 were also reduced. Moreover, aurantio-obtusin suppressed LPL-induced $I{\kappa}B-{\alpha}$ degradation. These results suggest that the down regulation of NO, $PGE_2$, IL-$1{\beta}$ and IL-6 expression by aurantio-obtusin are achieved by the downregulation of NF-${\kappa}B$ activity.