• Korean Journal of Metals and Materials
• /
• v.50 no.12
• /
• pp.891-896
• /
• 2012

Nanopowders of MgO and $TiO_2$ were made by high energy ball milling. The rapid synthesis and sintering of the nanostructured $MgTiO_3$ compound was investigated by the high-frequency induction heated sintering process. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition grain growth. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties. As nanomaterials possess high strength, high hardness, excellent ductility and toughness, undoubtedly, more attention has been paid for the application of nanomaterials. A highly dense nanostructured $MgTiO_3$ compound was produced with simultaneous application of 80 MPa pressure and induced current within 2 min. The sintering behavior, gain size and mechanical properties of $MgTiO_3$ compound were investigated.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.3
• /
• pp.883-890
• /
• 2021

In this study, we investigated the melanogenesis inhibitory effects of Rubus crataefifolius Leaf Extract (RCLE) in B16F10 melanoma cells. We examined the effects of RCLE on the melanin contents and tyrosinase activity, as well as the protein expression levels of the melanogenic enzymes TRP-1, TRP-2, and MITF in α-MSH -stimulated B16F10 melanoma cells. RCLE effectively inhibited tyrosinase activity and melanogenesis, suppressed the phosphorylation of PKA and CREB, and expression of MIT involved in the melanogenesis pathway, and down-regulated expression of melanogenesis related proteins. These result suggest that RCLE inhibited α-MSH-stimulated melanin synthesis by suppressing MITF expression. Therefore, our study suggests that RCLE has potential as a safe treatment for excessive pigmentation or as a natural ingredient in cosmetics.

• Journal of Life Science
• /
• v.26 no.12
• /
• pp.1422-1430
• /
• 2016

This study was performed to investigate the modulatory effects of two prototypes of Panax ginseng saponin fractions, 20(S)-protopanaxadiol saponins (PDS) and 20(S)-protopanaxatriol saponins (PTS), on the induction of inflammatory mediators in lipopolysaccharide (LPS)-treated RAW264.7 murine macrophage cells. For this purpose, RAW264.7 cells were treated with LPS ($10{\mu}g/ml$) before, after, or simultaneously with PDS or PTS ($150{\mu}g/ml$), and the released level of nitric oxide (NO) and expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were evaluated. When RAW264.7 cells were treated with LPS and ginseng saponin fractions simultaneously for 24 hr, PTS, compared to PDS, more strongly attenuated the NO production induced by LPS treatment. When the cells were pretreated with LPS for 2 hr followed by PDS or PTS treatment for 24 hr, both ginseng saponins strongly reduced NO release. The pretreatment of RAW264.7 cells with PDS or PTS for 2 hr followed by LPS treatment for 24 hr significantly attenuated the LPS-induced production of NO. PTS showed stronger inhibitory potency to NO generation than PDS. Our western blot experiment showed that both PDS and PTS ($150{\mu}g/ml$) also significantly down-regulated the expressions of iNOS and COX-2 induced by LPS treatment. Our results suggest that both PDS and PTS possess strong protective effects against LPS-stimulated inflammation and that their protective effects are mediated by the suppression of NO synthesis via down-regulation of pro-inflammatory enzymes, iNOS, and COX-2 in the RAW264.7 cells.

• Journal of Applied Biological Chemistry
• /
• v.57 no.4
• /
• pp.365-371
• /
• 2014

In the present study, we investigated the biological activities of Xylosma congesta leaf ethanol extract (XCO) using a variety of in vitro and cell culture model systems for anti-melanogenic, anti-wrinkle, anti-inflammatory and anti-oxidant activities. First, XCO markedly inhibited ${\alpha}$-melanocyte stimulating hormone-stimulated melanin synthesis in B16F10 cells. Secondly, XCO marginally induced procollagen synthesis in CCD-986SK cells. Thirdly, XCO dose-dependently suppressed lipopolysaccharide-induced nitric oxide (NO) production in RAW 264.7 cells. XCO did not affect cell viability at different concentrations used in this study, indicating that XCO-mediated inhibition of melanin, procollagen and NO synthesis is not mediated by cytotoxicity. Finally, XCO was found to exert anti-oxidant effect. Taken together, these findings demonstrate for the first time that XCO possesses anti-melanogenic, anti-wrinkle, anti-inflammatory and anti-oxidant activities, and suggest further evaluation and development of XCO as a functional supplement or cosmetic that may be useful for whitening skin, reducing wrinkles and treating inflammatory responses.

• Journal of Applied Biological Chemistry
• /
• v.59 no.4
• /
• pp.305-311
• /
• 2016

This study investigated the effects of a mixture of fenugreek seeds and Lespedeza cuneata extracts on testosterone synthesis in TM3 cells that were oxidatively stressed with $H_2O_2$. In order to oxidatively stress TM3 cells, the cells were treated with $50{\mu}M$ hydrogen peroxide for 4 hr in serum-free media. Yagwanmun-horopa mixture (YHM) showed neither cytotoxicity nor increment of cell proliferation in the oxidatively stressed TM3 cells in any concentration. When the cells were treated with hydrogen peroxide, testosterone levels decreased, but the testosterone level was returned to that of the control level in the presence of YHM. In order to find out the reasons for the increase of testosterone, the expression of the genes involved in the synthesis or disintegration of testosterone. On the other hand, the levels of $3{\beta}$-HSD4 and 17, 20-desmorase, which are involved in testosterone synthesis, were decreased through the use of hydrogen peroxide and were recovered through YHM treatment. Aromatase and $5{\alpha}$-reductase2, which convert testosterone to estradiol and dihydrotestosterone, respectively, were increased through the use of hydrogen peroxide, and were returned to control level through YHM treatment. These results suggest that YHM does not affect TM3 cell proliferation. However, YHM increases the expression of testosterone-synthesizing enzyme, which was decreased through oxidative stress, and decreases the expression of testosterone- converting enzyme, which was increased through oxidative stress. Therefore, it is reasonable that YHM has strong recovery activity on testosterone to normal level, even in the oxidatively stressed TM3 cells which mimics the andropause state.

• Journal of Energy Engineering
• /
• v.16 no.2
• /
• pp.83-92
• /
• 2007

In view of stringent environment regulations to control the emission of green house gases and also depleting fossil fuel reserves, it is high quality desirable to develop alternative technologies to produce high quality fuels. To this end Biomass to Liquid (BTL) technology has received much attention in recent years. BTL process generally consists of gasification of biomass to produce bio-syngas, cleaning and control of $H_{2}/CO$ mole ratio of bio-syngas and Fischer-Tropsch synthesis & upgrading systems. Choren, Germany has first developed the commercial BTL process using unique gasification system i.e., Carbo-V. A new technology to remove tars and BTX has been developed by ECN in Netherlands employing a gasification system combined with OLGA technology. Several other countries including USA and Japan are showing great interest in BTL technology. Thus in view of our national energy security and also the environmental regulations, it is essential to develop alternative technologies like BTL in order to meet the increasing demand of energy though our insufficient biomass resources. In this paper we present an overview and development status of BTL-diesel technology.

• Korean Journal of Veterinary Research
• /
• v.43 no.3
• /
• pp.383-392
• /
• 2003

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important regulators on the development of maternal tissues during pregnancy. This study was performed to examine the relationship between maternal IGFs/IGFBPs system (i.e: IGF-I, II, their receptors, and IGFBPs) in pre- and post-partum rats. The liver and kidney are important organs for the synthesis of IGFs and IGFBPs in adults. The levels of materanal IGFs and IGFBPs in serum, liver, and kidney were examined at 14 and 21 days of gestation and at 3, 7, 11, and 14 days after birth. The expression of IGFs and their receptors mRNA was also examined in fetal and maternal rat liver, kidney. IGF-I concentrations in maternal serum and liver were decreased during pregnancy. However, IGF-I concentration in maternal kidney was increased, having maximal effect at 14 days of gestation. IGF-I concentrations were decreased in serum, liver, and kidney of postpartum rat, compared to control (p < 0.05). On the other hand, IGF-II concentrations in serum, liver, and kidney were increased during pregnancy (p<0.05) and gradually decreased to control level in postpartum period. The levels of IGFBP-3 and IGFBP-2 are expressed in serum, liver, and kidney. However, IGFBP-3 is mainly expressed in serum and liver, and IGFBP-2 in kidney. The levels of IGFBP-3 and IGFBP-2 in maternal serum were markedly decreased during pregnancy and gradually recovered to control level during postpartum period by western ligand blotting. However, there was no change of IGFBP-3 and IGFBP-2 levels by western immunoblotting. The levels of IGFBP-3 and IGFBP-2 in maternal liver and kidney also showed the same pattern of serum, although the main IGFBP is different. In normal rat serum, IGF-I 150 kDa and 50 kDa carrier proteins were detected. The level of IGF-I 150 kDa carrier proteins in pregnant rat was decreased compared to normal rat, but that of 50 kDa carrier proteins was increased. IGFBP-3 protease activity was identified in pregnant rat serum and maternal placenta, and it was inhibited by EDTA ($Ca^{2+}$ chelating agent) and aprotinin (serine proteinase inhibitor). Taken together, these results suggest that the changes of IGFs and IGFBPs in maternal rats are regulated by liver and kidney IGFs and their receptors mRNA during the pregnancy.

• Journal of Life Science
• /
• v.18 no.6
• /
• pp.884-890
• /
• 2008

Genistein, an isoflavone in soybean products, is a potential chemopreventive agent against various types of cancer. There are several studies documenting molecular alterations leading to cell cycle arrest at G2/M phase and induction of apoptosis; however, its mechanism of action and its molecular targets on the prostaglandin $E_2$ ($PGE_2$) production and telomere length regulation in human cancer remain unclear. In this study, we investigated the effect of genistein on the levels of cyclooxygenases (COXs) and telomere regulatory components of several human cancer cell lines (T24, human bladder carcinoma cells; U937, human leukemic cells; AGS, human stomach adenocarcinoma cells and SK-MEL-2, human skin melanoma cells). Genistein treatment resulted in the inhibition of cancer cell proliferation in a concentration-dependent manner. It was found that genistein treatment markedly decreased the levels of COX-2 mRNA and protein expression without significant changes in the expression of COX-1, which was correlated with a decrease in $PGE_2$ synthesis. Genistein treatment also partly inhibited the levels of human telomerase reverse transcriptase (hTERT) as well as human telomerase RNA (hTR) and telomerase-associated protein (TEP)-1, and the activity of telomerase. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of genistein.

• Applied Chemistry for Engineering
• /
• v.25 no.2
• /
• pp.121-133
• /
• 2014

Block copolymers including ABA triblock architectures are useful as thermoplastic elastomers and toughened plastics depending on the relative glassy and rubbery content. These materials can be blended with other polymers and utilized as additives, toughening agents, and compatibilizers. Most of commercially available block copolymers are derived from petroleum. Renewable alternatives are attractive considering the finite supply of fossil resources on earth and the overall economic and environmental expenses involved in the recovery and use of oil. Furthermore, tomorrow's sustainable materials are demanding the design and implementation with programmed end-of-life. The present review focuses on the preparation and evaluation of new classes of renewable ABA triblock copolymers and also emphasizes on the use of carbohydrate-derived poly(lactide) or plant-based poly(olefins) having a high glass transition temperature and/or high melting temperature for the hard phase in addition to the use of bio-based amorphous hydrocarbon polymers with a low glass transition temperature for the soft components. The combination of multiple controlled polymerizations has proven to be a powerful approach. Precision-controlled synthesis of these hybrid macromolecules has led to the development of new elastomers and tough plastics offering renewability, biodegradability, and high performance.

• Journal of Adhesion and Interface
• /
• v.11 no.2
• /
• pp.41-49
• /
• 2010

Furan-containing epoxide monomers (8, 9) were designed and synthesized as carbon-neutral, environment-friendly adhesion material. Bicyclic skeleton were constructed using the Diels-Alder reaction of furan and methyl acrylate, both readily accessible starting material from a biomass via bio-refinery process. After reduction of ester functionality, resulting hydroxyl moieties were coupled to epichlorohydrin to provide the epoxy-functionalized furanic monomers (8, 9). The structure of new furanic monomers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy. As UV-curable monomers, basic properties such as UV curing time and the extent of UV curing were evaluated by photo DSC. Photo-curing shrinkages were measured by linear variable differential transformer transducer (LVDT) and the effect of molecular structure on shrinkage was considered. In addition, new synthetic compounds showed the shear strength over 3 MPa when they were photo-cured between polycarbonate plates, which indicates these compounds are feasible to use as photo-curable adhesive materials.