• Journal of the Korean GEO-environmental Society
• /
• v.10 no.7
• /
• pp.25-32
• /
• 2009

The main objective of this study was to examine the removal properties of Cu from water by inflated vermiculites. The component of vermiculites was analyzed by XRF and the concentration of Copper ion was measured by UV-VIS. Serial batch Kinetic tests and batch sorption tests were conducted to determine the removal characteristics for Cu in aqueous solutions. The result shows that removal rate, $K_{obs}$, of Cu are 0.73, 1.52, and 1.71 for initial pH 3, pH 4, pH 5, respectively, and are 3.19, 1.90, and 0.73 for the initial concentration of $1mg\;L^{-1}$, $5mg\;L^{-1}$, $10mg\;L^{-1}$, respectively. It leads to the conclusion that the removal rates are inversely proportional to the initial Cu concentration and are increased proportionally to the initial pHs. Finally, Sorption data were correlated with both Langmuir and Freundlich isotherms. As a result, Langmuir and Freundlich models were well fitted to batch isotherm data with good values of the determination coefficient. but the determination coefficient value for the Freundlich model fit was slightly higher than that of Langmuir model (0.965 for the Freundlich model and 0.936 for the Langmuir model). Using the Langmuir model, the maximum sorption capacity ($Q_{max}$), Freundlich partition coefficient, and the numerical value of n wrer estimated as $1,250mg\;kg^{-1}$, $635.1L\;kg^{-1}$ and 1.69, respectively. These results show that the inflated vermiculites could be used as an excellent adsorbent for copper contained in various types of aqueous solutions.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.8
• /
• pp.1184-1194
• /
• 2020

Melanin is a major factor that darkens skin color as one of the defense systems to prevent the harmful effects of UV light. However, darkened skin from the localized or systemic accumulation of melanin is viewed in many cultures as an esthetic problem. Consequentially, searching for anti-melanogenic agents from natural sources is very popular worldwide. Previous screening of fermented rice products, obtained from various rice cultivars fermented with different sources of loog-pang (Thai traditional fermentation starter), revealed that the highest ability to reduce the melanin content in B16F10 melanoma cells was from unpolished black rice fermented with a defined starter mixture of microbes isolated from loog-pang E11. The aim of this study was to investigate the mechanism of the fermented unpolished black rice (FUBR) on the inhibition of melanogenesis in B16F10 melanoma cells. The strongest reduction of cellular melanin content was found in the FUBR sap (FUBRS). The melanin reduction activity was consistent with the significant decrease in the intracellular tyrosinase activity. The FUBRS showed no cytotoxic effect to B16F10 melanoma or Hs68 human fibroblast cell lines. It also significantly reduced the transcript and protein expression levels of tyrosinase, tyrosinase-related protein 1 (TYRP-1), TYRP-2, and microphthalmia-associated transcription factor. Furthermore, it induced a significantly increased level of phosphorylated ERK, p38 and Akt signaling pathways, which likely contributed to the negative regulation of melanogenesis. From these results, a model for the mechanism of FUBRS on melanogenesis inhibition was proposed. Moreover, these results strongly suggested that FUBRS possesses anti-melanogenesis activity with high potential for cosmeceutical application as a skin depigmenting agent.

• Journal of Biomedical Engineering Research
• /
• v.34 no.3
• /
• pp.111-116
• /
• 2013

Finite element analysis(FEA) has been extensively applied in the analyses of biomechanical properties of stents. Geometrically, a closed-cell stent is an assembly of a number of repeated unit cells and exhibits periodicity in both longitudinal and circumferential directions. This study concentrates on various parameters of the FEA models for the analysis of drug-eluting biodegradable polymeric stents for application to the treatment of coronary artery disease. In order to determine the mechanical characteristics of biodegradable polymeric stents, FEA was used to model two different types of stents: tubular stents(TS) and helicoidal stents(HS). For this modeling, epigallocatechin-3-O-gallate (EGCG)-eluting poly[(L-lactide-co-${\varepsilon}$-caprolactone), PLCL] (E-PLCL) was chosen as drug-eluting stent materials. E-PLCL was prepared by blending PLCL with 5% EGCG as previously described. In addition, the effects of EGCG blending on the mechanical properties of PLCL were investigated for both types of stent models. EGCG did not affect tensile strength at break, but significantly increased elastic modulus of PLCL. It is suggested that FEA is a cost-effective method to improve the design of drug-eluting biodegradable polymeric stents.

• Proceedings of the KOSOMBE Conference
• /
• v.1995 no.11
• /
• pp.26-33
• /
• 1995

Silicone Rubber (SR)-based potassium- and sodium-selective solid-state electrodes have been developed for the portable blood electrolyte analyzer system. The electrochemical performance of these electrodes have been evaluated with a static experimental setup and with the newly developed blood electrolyte analyzer system (model; HS603). It has been shown that their potentiometric properties are essentially comparable to those of PVC-based ion-selective electrodes, but with greatly improved lifetime (200 and 40 days for potassium and sodium sensors, respectively) and potential stability (within $\pm0.1$ mV). Clinical tests have been performed with real serum samples and the results have been compared with those obtained from Ciba-Corning BGA 288 system; correlations were excellent, proving its practical utility as a new commercial system.

• Journal of Ocean Engineering and Technology
• /
• v.23 no.5
• /
• pp.45-53
• /
• 2009

In this study, Finite Element Analysis (FEA) was used to decide three kinds of material property of vibration proof rubber with the unique characteristic of non-linear and large deformation. As well, three types of hardness (Hs 50, 55, 60) were compared with the result of fatigue tests, fatigue life was able to be predicted. The request for fatigue life becomes strict more and more as increasing stress under conditions like a compaction, high load and high temperature for parts because it is main characteristics of rubber mount for automotive. Regarding to the fatigue life under dynamic deformation condition, it can be predicted as checking forced deformation extends and its frequency and its strain-life curve. As for material property tests of uniaxial tension test, uniaxial compression test, pure shear test, Ogden model was used for FEA by observing relations between stress and strain's rate as curve fitting. As a result of FEA, fatigue life for rubber mount was predicted and accorded well with the experimental data of fatigue test with hourglass specimens. In addition, its property of the predictable fatigue life method suggested in this study was accorded well with the experimental data by comparing the predicted fatigue life of FEA with the result of fatigue test for rubber component of engine rubber mount.

• ALGAE
• /
• v.30 no.2
• /
• pp.147-161
• /
• 2015

Brown algal extracts have long been used as feed supplements to promote health of farm animals. Here, we show new molecular insights in to the mechanism of action of a fucose containing polymer (FCP) rich fraction from the brown seaweed Ascophyllum nodosum using the Caenorhabditis elegans-Pseudomonas aeruginosa PA14 infection model. FCP enhanced survival of C. elegans against pathogen stress, correlated with up-regulation of key immune response genes such as: lipases, lysozyme (lys-1), saponin-like protein (spp-1), thaumatin-like protein (tlp-1), matridin SK domain protein (msk-1), antibacterial protein (abf-1), and lectin family protein (lfp). Further, FCP caused down regulation of P. aeruginosa quorum sensing genes: (lasI, lasR, rhlI, and rhlR), secreted virulence factors (lipase, proteases, and elastases) and toxic metabolites (pyocyanin, hydrogen cyanide, and siderophore). Biofilm formation and motility of pathogenic bacteria were also greatly attenuated when the culture media were treated with FCP. Interestingly, FCP failed to mitigate the pathogen stress in skn-1, daf-2, and pmk-1 mutants of C. elegans. This indicated that, FCP treatment acted on the regulation of fundamental innate immune pathways, which are conserved across the majority of organisms including humans. This study suggests the possible use of FCP, a seaweed component, as a functional food source for healthy living.

• The Journal of Korean Medicine
• /
• v.39 no.1
• /
• pp.1-12
• /
• 2018

Objectives: Astragalus membranaceus has been reported to inhibit immune responses, but its effect on hair loss is not clear. In this study, the effect of A. membranaceus extract (AM) on hair regrowth in C57BL/6 mice with natural hair loss in the telogen phase was investigated. Methods: Mice with natural hair loss were topically treated with 1% AM on the dorsal skin for 2 weeks. Dorsal skin samples were stained with hematoxylin and eosin and probed with an anti-mouse CD8a IgG. The mRNA expression levels of tumor necrosis factor $(TNF)-{\alpha}$, interferon $(IFN)-{\gamma}$ and interleukin (IL)-4 were measured by reverse transcription polymerase chain reaction and quantitative real-time polymerase chain reaction. Results: AM treatment induced hair regrowth in hair loss mice, while control mice suffered continued hair loss. Tapering hair shafts and broken hair follicles were decreased as well as CD8+ T lymphocyte infiltration. In addition, the expressions of $TNF-{\alpha}$, $IFN-{\gamma}$ and IL-4 were reduced by AM treatment. Also, AM treatment significantly increased the KGF expressions in Hs68 fibroblast cells. Conclusion: These results suggest that topical application of A. membranaceus may be an alternative therapy for hair loss.

• Korean Journal of Environmental Agriculture
• /
• v.11 no.3
• /
• pp.235-242
• /
• 1992

Organic ligands in the environments are expected to play an important role in regulating the biotoxicity and fate of pesticides. Influences of dissolved humic and fulvic acids on the phytotoxicity of Paraquat were investigated using a bioassay with hydroponically grown rye as indicator species. Levels of Paraquat in water culture media were ranged from 0 to $12_{{\mu}M}$ and those of humic or fulvic acid were 1.0mM as a soluble carbon. Media were prepared in a factorial combination with pHs of 4.5, 6.5 and 8.5, Standard curves of necrosis days, fresh weight, and growth rates, as Phytotoxicity Indices, versus Paraquat concentrations were employed to evaluate the effects of organic ligands on phytotoxicity of paraquat. Organic ligand itself had little effect on rye growth, but Paraquat showed a high degree of toxicity. Paraquat started to show an intensive injury to rye at $0.4{\sim}0.6{{\mu}M}$ and upper critical phytotoxic concentration was estimated to be 11.0${{\mu}M}$ In the presence of organic ligands, times required to cause necrosis due to Paraquat were delayed upto 40%. Fresh weights and growth rates were upto 20% higher in treatments of organic ligands plus Paraquat than that of Paraquat alone. Results demonstrated that complexation of organic ligand with Paraquat reduced the bioabailability of Paraquat to rye.

• Nutrition Research and Practice
• /
• v.6 no.3
• /
• pp.246-253
• /
• 2012

The Framingham risk score (FRS) has been used to assess the risk of a cardiovascular event and to identify patients for risk factor modifications. Therefore, the purpose of this study was to evaluate the relationship of the FRS with dietary intake and inflammatory biomarkers. We conducted a cross-sectional study of 180 men ($49.2{\pm}10.2$ years) with MS. Serum levels of high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), and adiponectin were examined. Participants were asked to complete the food frequency questionnaire (FFQ) using the previous 1 year as a reference point. The absolute cardiovascular disease (CVD) risk percentage over 10 years was calculated to estimate the FRS, which was classified as low risk (< 10%), intermediate risk (10-20%), and high risk (> 20%). Mean intake of polyunsaturated fatty acids was lower in subjects who had > 20% FRS than in subjects who had < 10% FRS ($3.7{\pm}1.9$ g/day vs. $4.7{\pm}1.9$ g/day; P < 0.05). Significant differences in the Index of Nutritional Quality of protein, phosphorus, iron, vitamin A, vitamin $B_1$, niacin, vitamin $B_6$, and vitamin C were observed between the > 20% FRS group and the < 10% FRS group (P < 0.05). IL-6 concentrations were significantly lower in subjects with a < 10% FRS than in subjects who were 10-20% FRS or > 20% FRS ($0.91{\pm}0.26$ vs. $1.48{\pm}033$ vs. $2.72{\pm}0.57$ pg/mL, respectively; P < 0.05). IL-6 and dietary intake of polyunsaturated fatty acids together explained 6.6% of the variation in FRS levels in a stepwise multiple regression model. Our results provide some evidence that dietary intake in the higher CVD risk group was inferior to that in the lower risk group and that dietary fat intake and IL-6 were associated with FRS and MS in Korean men.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.676-680
• /
• 2003

Dissolution of magnetite powders by 0.05 M citric acid was investigated at $50^{\circ}C$. All the tests were performed in the pH range between 2.0 to 5.0, which was adjusted using nitric acid or sodium hydroxide. Concentration of each of the dissociated chemical species of citric acid under various solution pHs was calculated using the ionization constants. Variation of zeta potential of magnetite with pH changes was also investigated. The dissolution reaction was explained by comparing the concentration of the dissociated chemical species of citric acid with the zeta potential. Longer than 3 h of induction time was required to dissolve the magnetite. The dissolution behaviour of magnetite was well described by the equation. The physical meaning of each parameter was explained successfully from the model equation.