Non-thermal atmospheric pressure (NAP) plasma has demonstrated potential in biomedical applications, such as cancer treatment, bactericidal sterilization, and cell growth promotion or inhibition. In this study, for the first time, we demonstrated on–off switching of cell cycle progression and regulated melanogenesis in normal human skin melanocytes by NAP plasma-activated medium (PAM). The melanocytes were exposed to NAP plasma at durations varying from 0 to 20 min, and the effects of PAM on cell proliferation, cell cycle progression, and melanogenesis were investigated. Although PAM showed no cytotoxicity, the proliferation of melanocytes was inhibited. The melanocyte cell cycle was arrested by PAM for a relatively short period (48 h), after which it recovered slowly. PAM promoted melanogenesis through the activation of the enzymes tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2. These effects seem to be related to reactive oxygen species induced by PAM. Our finding that PAM modulates the cell cycle may provide insight into the recurrence of cancer. The regulation of the melanogenesis of melanocytes may facilitate the control of skin tone without incurring negative side effects.

The authors present the characteristics of hydrogenated microcrystalline silicon (μc-Si:H) thin films deposited from an SiH4/H2 in 40 MHz plasma enhanced chemical vapor deposition system equipped with a multihole-array showerhead. The effects of a hole-array structure are analyzed in terms of deposition rate, crystallinity, and electrical conductivity of the μc-Si:H film. The effects of process parameters, such as SiH4 concentration, radio frequency power, and total gas flow rate are also investigated. The deposition rate of a multihole-array electrode is generally lower compared with that of the flat electrode. However, a higher deposition rate is found in the deep and dense hole region when the hole shape and density are varied on the electrode. The crystallinity and conductivity are almost not affected by hole dimension and density. It is demonstrated that the multihole-array electrode can be a useful tool for uniformity improvement in a large-sized very high frequency capacitively couple plasma μc-Si:H deposition system.

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-For a higher definition discharge cell, the method of high speed addressing is necessary. In order to modify the surface charges, the liquefied TiO2 or MgO powder is added on MgO layer in front glass and on the phosphor in rear glass in micro barrier discharge. Both the electro-optical properties and the discharge time lag characteristics are measured from 4 inch. test panel, such as the discharge voltage, current, luminance, luminous efficacy and discharge time lag. As the results, the statistic time lag is improved by about 40 %.