In this study, to evaluate the usefulness of Rhododendron weyrichii Maxim. as a whitening agent, the whitening effects of its extracts were investigated in alpha-melanocyte-stimulating hormone (a-MSH)-induced B16F10 melanoma cells. No toxicity was noted in either B16F10 melanoma cells or HaCaT keratinocyte cells that were exposed to the hot water or 70% ethanol extracts of R. weyrichii Maxim. (RW-H and RW-E, respectively). Moreover, both the RW-H and RW-E extracts dose-dependently inhibited a-MSH-induced melanin production in B16F10 melanoma cells, with inhibitory effects of 52.5% and 51.6%, respectively, at a concentration of 200 µg/mL. The RW-H and RW-E extracts also inhibited intracellular tyrosinase activity in a dose-dependent fashion. Western blot analyses showed that the RW-H and RW-E extracts decreased tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2 expression. Additionally, we found that ñ-coumaric acidcontaining RW-H and RW-E extracts could be used as hypopigmentation agents since they suppress melanogenesis. Collectively, our results suggest that RW-H and RW-E extracts have the potential to serve as functional cosmetic agents, including whitening agents.
As a poly (3,4-ethylenedioxythiophene) doped with poly (styrene sulfonate), PEDOT:PSS is well known for its conductive polymer in a field of organic electronics. PEDOT:PSS can be widely operated as electronics under low temperature conditions; however, the layer can be easily damaged by high temperature conditions, while in fabrication or in the operation of electronics. Therefore, enhancing the thermal stability of PEDOT:PSS can be a novel strategy for both fabrication and operating varieties. Herein, PEDOT:PSS is the surface-treated with tannic acid to increase the thermal stability. A large number of phenols in tannic acid not only provide UV absorption ability, but also thermal stability. Therefore, tannic-treated PEDOT:PSS film sustained 150 °C for 96 h because of its initial conductivity. Moreover, surface properties and its bonding nature was further examined to show that the tannic acid does not damage the electrical and film properties. The method can be widely used in the field of organic electronics, especially because of its high stability and the high performance of the devices.
Steady state visual evoked potential (SSVEP) has been actively studied because of its short training time, relatively higher signal-to-noise ratio, and higher information transfer rate. There are two popular analysis methods for SSVEP signals: power spectral density analysis (PSDA) and canonical correlation analysis (CCA). However, the PSDA is known to be vulnerable to noise due to the use of a single channel. Although conventional CCA is more accurate than PSDA, it may not be appropriate for the real-time SSVEP-based BCI system when it has short time window length because it uses sinusoidal signals as references. Therefore, the two methods are not efficient for the real-time BCI system that requires a short TW and a high recognition accuracy. To overcome this limitation of the conventional methods, this paper proposes a frequency recognition method with a combination of CCA and PSDA using the difference between powers of canonical variables obtained from the results of CCA. Experimental results show that the performance of the combination of CCA and PSDA is better than that of CCA for the case of a short TW.
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