Gyeongju University

About: Gyeongju University is a education organization based out in Gyeongju, South Korea. It is known for research contribution in the topics: Aerosol & Aethalometer. The organization has 63 authors who have published 109 publications receiving 1099 citations. The organization is also known as: Korea Tourism University.

Physicochemical characteristics and radiative properties of Asian dust particles observed at Kwangju, Korea, during the 2001 ACE-Asia intensive observation period

Abstract: [1] Optical properties of atmospheric extinction, scattering, and absorption coefficients were measured continuously with a transmissometer, an integrating nephelometer, and an aethalometer, respectively. Three Asian dust storm events had been observed at Kwangju on 22 March, 11–13 April, and 25–26 April 2001. The physicochemical and optical properties of Asian dust aerosols were analyzed for those three cases and compared with those observed under clean, marine, and hazy urban atmospheric conditions. Their chemical composition varied depending on the source region and the transport path of the air mass. The first Asian dust storm particles, which originated from the northwestern Chinese desert regions, showed typical dust aerosol characteristics of high loading of mineral dust. The second one, which originated initially from the northwestern Chinese desert regions, had been impacted by longrange-transported air pollutants, resulting in increased concentrations of sulfate and organic carbon particles. The third one, which originated from the northeastern Chinese sandy areas, had traveled south to Kwangju, resulting in increased elemental carbon and organic carbon concentrations. Aerosol chemical and optical properties under clean continental, southeastern marine, and stagnant local pollution conditions were also analyzed. The mass scattering coefficient and single-scattering albedo in the fine and coarse modes were determined for three Asian dust event days. The concentration of black carbon (BC) aerosol in the fine and coarse modes was measured with an aethalometer by alternately switching between a particulate-matter-smaller-than-2.5-mm (PM2.5) and a PM10 inlet to it. It was found that BC mass concentration in the coarse mode measured by an aethalometer (BCac) increased because of agglomerated black carbon particles and high loading of dust particles. Single-scattering albedo w increased to 0.93, 0.90, and 0.84 for the three Asian dust events, respectively, while it was 0.85 for mean w during other times. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0345 Atmospheric Composition and Structure: Pollution— urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; KEYWORDS: Asian dust, physicochemical properties, carbonaceous particle Citation: Kim, K. W., Z. He, and Y. J. Kim (2004), Physicochemical characteristics and radiative properties of Asian dust particles observed at Kwangju, Korea, during the 2001 ACE-Asia intensive observation period, J. Geophys. Res., 109, D19S02,

Hesperidin inhibits expression of hypoxia inducible factor-1 alpha and inflammatory cytokine production from mast cells

Abstract: The citrus unshiu peel has been used traditionally as a medicine to improve bronchial and asthmatic conditions or cardiac and blood circulation in Korea, China, and Japan. Here, we report the effects of citrus unshiu peel water extract (CPWE) on the phorbol myristate acetate (PMA)+calcium ionophore A23187-induced hypoxia-inducible factor-1alpha (HIF-1alpha) activation and inflammatory cytokine production from the human mast cell line, HMC-1 cells. We compared CPWE with hesperidin, a common constituent of citrus unshiu. CPWE and hesperidin inhibited the PMA+A23187-induced HIF-1alpha expression and the subsequent production of vascular endothelial growth factor (VEGF). In addition, CPWE suppressed PMA+A23187-induced phosphorylation of the extracellular signal-regulated kinase (ERK). We also show that the increased cytokines interleukin (IL)-1beta, IL-8, and tumor necrosis factor (TNF)-alpha level was significantly inhibited by treatment of CPWE or hesperidin. In the present study, we report that CPWE and hesperidin are inhibitors of HIF-1alpha and cytokines on the mast cell-mediated inflammatory responses.