• Macromolecular Research
• /
• v.16 no.2
• /
• pp.103-107
• /
• 2008

Carbon nanodots were prepared by the pyrolysis of a triblock copolymer. The triblock copolymer, poly(methyl methacrylate)-b-polystyrene-b-poly(methyl methacrylate) was synthesized by atom transfer radical polymerization using an initiator containing a diacetylene group. A polymer thin film on a mica substrate was prepared by spin-casting at 2,000 rpm from a 0.5 wt% toluene solution of the triblock copolymer. After drying, the cast film was vacuum-annealed for 48 h at $160^{\circ}C$. The annealed film formed a spherical morphology of polystyrene domains with a diameter of approximately 30 nm. The film was exposed to UV irradiation to induce a cross-linking reaction between diacetylene groups. In the subsequent pyrolysis at $800^{\circ}C$, the cross-linked polystyrene spheres were carbonized and the poly(methyl methacrylate) matrix was eliminated, resulting in carbon nanodots deposited on a substrate with a diameter of approximately 5 mn.

• Korean Journal of Materials Research
• /
• v.25 no.3
• /
• pp.144-148
• /
• 2015

Cubic mesocrystal $CeO_2$ was synthesized via a hydrothermal method with glutamic acid ($C_5H_9NO_4$) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal $CeO_2$ compared to commercial $CeO_2$ particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination. With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (${\geq}380nm$). The decoloring rate can exceed 100% after 300 min.

• KSBB Journal
• /
• v.29 no.1
• /
• pp.50-57
• /
• 2014

NF-${\kappa}B$ is a transcriptional factor which is involved in many biological processes including immunity, inflammation, and cell survival. Many investigators studied on the mechanism involved in activation of NF-${\kappa}B$ signalling pathway via ubiquitination and degradation of $I{\kappa}B$ regarding skin disease. Some specific molecules including Akt, MEK, p38 MAP Kinase, Stat3, et al. represent convergence points and key regulatory proteins in signaling pathways controlling cellular events such as growth and differentiation, energy homeostasis, and the response to stress and inflammation. Ultraviolet (UV) irradiation has many adverse effects on skin, including inflammation, alteration in the extracellular matrix, cellular senescence, apoptosis and skin cancer. Prunus mume, a naturally derived plant extract, has beneficial biological activities as blood fluidity improvement, anti-fatigue action, antioxidative and free radical scavenging activities, inhibiting the motility of Helicobacter pyolri. Previous reports on various beneficial function prompted us to investigate UVB-induced or other immunostimulated biological marker regarding P. mume extract. P. mume extract suppresses UVB-induced cyclooxygenase-2 (COX-2) expression in mouse skin epidermal JB6 P+ cells. The activation of activator protein-1 and nuclear factor-${\kappa}B$ induced by UVB was dose-dependently inhibited by P. mume extract treatment. This results suggest that P. mume extracts might be used as a potential agents for protection of inflammation or UVB induced skin damage.

• KSBB Journal
• /
• v.28 no.5
• /
• pp.287-294
• /
• 2013

Stained and discolored hair will be damaged by the shampooing, daily UV disposal, and the use of hair dryer. Thus many studies about the effect of various natural substances on the re-secure the skin and scalp are recently reported. This study was carried out to investigate the effect of green tea (Camelloia sinensis) seed oil on colored (dyed) and decolored (bleached) hair. The beneficial effects of green tea seed oil are already well known, but little research has been done about the hair treatment and fade-resistant effect. Dyed and bleached hair was pretreated with green tea seed oil to determine the tensile strength and elongation of the hair, to analyze the hair surface using SEM, and to compare the color fade using spectrocolormeter. The results showed that the tensile strength increased with green tea seed oil pretreatment samples for virgin, dyed, and bleached hairs. Elongation showed the reverse results showing the presence of hair treatment effect. The results of the surface pre-treatment in all groups analyzed by SEM, the hair cuticle became sharper, so coating effect were identified with all samples. The value of the $L^*$, $a^*$, $b^*$ decreased with washed hairs damaged by UV irradiation and the values were decreased also in dyed and bleached hair. In summary, green tea seed oil prevent reinjury to the heat and UV rays for colored and decolored hairs. Cosmetic practice effects of the oil were identified in the field to be appropriate to the customer's skin and scalp that natural cosmetic oils would like to offer.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.35 no.1
• /
• pp.57-63
• /
• 2009

UV irradiated skin cells produce reactive oxygen species (ROS). ROS is known to be the primary cause of skin inflammation that is eventually leading to skin aging through decrease of collagen in the dermis. In this study, we evaluated basic efficacy of anti-aging, anti-inflammation and anti-melanogenesis using two antioxidative mineral-bio waters (Mineral-bio water 1 (MIBA-W1) and Mineral-bio water 2 (MIBA-W2)). Both antioxidative mineral-bio waters reduced TNF-${\alpha}$ expression which was induced upon UV irradiation. MIBA-W 1 increased collagen synthesis from UVB irradiated fibroblast at 0.01 % concentration but MIBA-W2 shows slight, but linear increase. Stimulation of melanogenesis by ${\alpha}$-MSH treatment in the cultured B16-F1 melanoma was significantly reduced by the treatment of MIBA-W2 in a dose dependent manner. Taken together, antioxidative MIBA-W1 and 2 seem to have potential applications as functional cosmetic materials.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.429-432
• /
• 2000

Chitosan scaffold is widely applied to drug delivery and tissue engineering. We have developed chitosan scaffolds, with various pore size, by differing freezing temperature and duration of ultraviolet (UV) irradiation, for reconstructing skin equivalent. Chitosan scaffold was coated with type I collagen, fibronectin and basic fibroblast growth factor (bFGF) in various combinations and concentrations, to evaluate the effect of extracellular matrix (ECM) and bFGF on cell adhesion, growth and differentiation of dermal fibroblasts. Human dermal fibroblasts, isolated from newborn foreskin and passaged between 3 and 5, were seeded on the top of scaffolds and cultivated for 2 weeks. We examined the morphology and the secretion of ECM of fibroblasts using scanning electron microsopy (SEM) and histochemistry. A stellate morphology of fibroblasts were seen in all groups. The scaffold coated with either type I collagen and bFGF or type I collagen and fibronectin, however, showed the best condtion of dermal fibroblasts, in that the highest cell number and ECM secretion were seen. On the contrary, scaffolds coated with all three factors, type I collagen, bFGF and fibronectin, showed lower number of cells and ECM secretion than scaffolds with two factors. There was a tendency of dose-dependence in all three factors for fibroblast growth and ECM secretion. In conclusion, we may suggest that chitosan scaffold coated with either type I collagen/bFGF or type I collagen/fibronectin could provide more favorable environment for the growth and differentiation of dermal fibroblasts.

• Korean Journal of Microbiology
• /
• v.49 no.1
• /
• pp.64-70
• /
• 2013

The greenhouse whitefly, Trialeurodes vaporariorum, is an economically important pest for greenhouse crops because they cause direct damage by feeding on plant nutrients and indirect damage as transmits many virus vectors. It has recently become a serious problem because of the continuous use of insecticide resulting in resistance among greenhouse whitefly population. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of nymph greenhouse whitefly were investigated. Isolated fungus was identified as Isaria fumosorosea by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin, and EF1-${\alpha}$ regions. This fungus was named as I. fumosorosea SDTv and tested for the virulence against nymphs T. vaporariorum and the cold activity, the thermotolerance and the stability of UV-B irradiation on conidia. Mortality rate of greenhouse whitefly showed from 84 to 100% and the virulence increased with increasing conidial concentrations, $1{\times}10^5$ to $10^8$ conidia/ml. Conidia were stable at $35^{\circ}C$, 0.1 $J/cm^2$ of UV irradiation and germinated after 8 days at $4^{\circ}C$. Additionally, the activities of chitinases and proteases produced by I. fumosorosea SDTv were varied according to the medium. In conclusion, I. fumosorosea SDTv which showed high mortality rate against greenhouse whitefly will be used effectively in the integrated pest management programs against the greenhouse whitefly.

• Applied Chemistry for Engineering
• /
• v.27 no.3
• /
• pp.307-312
• /
• 2016

Lead molybdate ($PbMoO_4$) was successfully synthesized using a facile surfactant-assisted hydrothermal process and characterized by XRD, Raman, TEM, PL, BET and DRS. We also investigated the photocatalytic activity of these materials for the decomposition of Rhodamine B under UV-light irradiation. From XRD and Raman results, well-crystallized $PbMoO_4$ crystals were successfully synthesized with the particle size of 52-69 nm. $PbMoO_4$ catalysts prepared in the presence of cetyltrimethyl ammonium bromide (CTAB) enhanced the photocatalytic activity compared to that of using P-25 and pure $PbMoO_4$ catalysts. The maximum photocatalytic activity of $PbMoO_4$ catalyst were observed when preparing it in pH 9 solution. The The PL peak at about 540 nm were observed for all catalysts and the excitonic PL signal increased proportionally with respect to the photocatalytic activity of Rhodamine B.

• Clean Technology
• /
• v.23 no.2
• /
• pp.196-204
• /
• 2017

CdZnS/ZnO composite was prepared through low-temperature precipitation and drying method. The property of CdZnS/ZnO as a recyclable photocatalyst for the degradation of rhodamine B (RhB) under visible light irradiation was examined. The sample was characterized by XRD, FE-SEM, XPS, UV-vis DRS and photoluminescence techniques before and after repeated reaction to investigate the change of properties during the photocatalytic reaction. During repeated reaction, the CdZnS/ZnO showed an improved photocatalytic activity and recycle stability. Among two feasible reaction pathways for photocatalytic degradation of RhB, the cleavage of conjugated chromophore was found to predominate over N-dealkylation of chromophore skeleton in the present work. The results indicate that the CdZnS/ZnO, prepared by a simple precipitation method, can be used as a visible-light driven photocatalyst with enhanced cycle stability and activity.

• Journal of the Korean Ceramic Society
• /
• v.50 no.4
• /
• pp.251-256
• /
• 2013

Multiwalled carbon nanotubes (MWCNTs) modified with Pd and $TiO_2$ composite catalysts were synthesized by the sol-gel method followed by solvothermal treatment at low temperature. The chemical composition and surface structure were characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Photocatalytic recycle degradation experiments were carried out under both UV and visible light irradiation in the presence of MWCNT/$TiO_2$ and Pd-MWCNT/$TiO_2$ composites. As expected, the nanosized Pd-MWCNT/$TiO_2$ photocatalysts had enhanced activity over the non Pd treated MWCNT/$TiO_2$ material in the degradation of a rhodamine B (Rh.B) solution. An increase in photocatalytic activity was observed and attributed to an increase in the photo-absorption effect by MWCNTs and the cooperative effect of Pd and $TiO_2$ nanoparticles. According to the recycled results, the as-prepared Pd-MWCNT/$TiO_2$ sample had a good effect on it.