Hyun-Ju Seo

Role of naringin supplement in regulation of lipid and ethanol metabolism in rats

The current study was performed to investigate the effect of naringin supplements on the alcohol, lipid, and antioxidant metabolism in ethanol-treated rats. Male Sprague-Dawley rats were randomly divided into six groups (n = 10) based on six dietary categories: ethanol and naringin-free, ethanol (50 g/L) plus low-naringin (0.05 g/L), ethanol plus high-naringin (0.125 g/L), and three corresponding pair-fed groups. The pair-fed control rats received an isocaloric diet containing dextrin-maltose instead of ethanol for 5 wks. Among the ethanol treated groups, the naringin supplements significantly lowered the plasma ethanol concentration with a simultaneous increase in the ADH and/or ALDH activities. However, among the ethanol-treated groups, naringin supplementation resulted in a significant decrease in the hepatic triglycerides and plasma and hepatic total cholesterol compared to that in the naringin-free group. Naringin supplementation significantly increased the HDL-cholesterol and HDL-C/total-C ratio, while lowering the AI value among the ethanol-treated groups. Hepatic lipid accumulation was also significantly reduced in the naringin-supplemented groups compared to the naringin-free group among the ethanol-treated groups, while no differences were found among the pair-fed groups. Among the ethanol-treated groups, the low-naringin supplementation resulted in a significant decrease in the levels of plasma and hepatic TBARS, whereas it resulted in higher SOD and GSH-Px activities and gluthathion levels in the liver. Accordingly, naringin would appear to contribute to alleviating the adverse effect of ethanol ingestion by enhancing the ethanol and lipid metabolism as well as the hepatic antioxidant defense system.

Analysis of microdischarge characteristics induced by synchronized auxiliary address pulse based on cross-sectional infrared observation in AC plasma display panel

The microdischarge characteristics induced by an auxiliary address pulse with the synchronized application of sustain pulses are investigated based on cross-sectional infrared (IR) (823 nm) observations taken using an image-intensified charge-coupled device (ICCD) camera. The IR observations reveal that the application of an auxiliary short pulse with an optimal amplitude and width to the address electrode enhances the intensity of the IR emission. Furthermore, the cross-sectional IR observations demonstrate that the effective infrared emission region is extended toward the address electrode. In addition, a numerical analysis using a two-dimensional fluid simulation is also applied to investigate the discharge mechanism relative to the amplitude and width of the auxiliary address pulse. As a result, the improvement in the luminance and luminous efficiency was found to be caused by a face discharge between the address and the sustain (or scan) electrodes, where the face discharge plays an important role in supplying priming particles to the surface discharge and lengthening the discharge path, which in turn intensifies the surface discharge.

Radiation characteristics of flexible circular dielectric waveguides in Q-band

In the millimeter wave frequencies of the Q-band, radiation losses of flexible circular PTFE rod and tube waveguides are measured with the variations of parameters such as operating frequencies, dielectric areas of guiding cross sections, curvature radii of the bending, and bend profiles of the S- and U-bend. We determine the radiation losses of the flexible waveguides, which current theory is not able to predict in the regime of some small curvature radius, and the lower limits of the curvature radii at which additional losses are not generated. The results can be explained by the concepts of the fractional power flows in the surrounding free space region of the guides.

Measurements on dielectric and radiation loss of flexible circular dielectric waveguides in Q-band

In Q-band, dielectric losses and radiation losses of flexible circular PTFE waveguides are measured with parameters such as operating frequency, areas of the dielectric region in guiding cross sections, and radii of curvature. The dielectric losses of the rod and tube waveguides show relatively good agreement with theoretical results. The radiation losses of the guides, which current theory cannot predict in the regime of small radius of curvature, are measured from differences between insertion losses and the dielectric losses. The validity of our results can be explained by the fractional power flow ratios in each region of the waveguides.

Characteristics of flexible dielectric tube waveguide in millimeter wave band

Flexible cylindrical dielectric tube waveguide in millimeter wave frequency is studied. Low transmission loss and bending loss can be obtained through an optimization of three parameters such as the thickness, the relative permittivity, and the inner radius of dielectric tube.