Ocean University of China

About: Ocean University of China is a education organization based out in Qingdao, China. It is known for research contribution in the topics: Population & Sea surface temperature. The organization has 27604 authors who have published 27886 publications receiving 440181 citations. The organization is also known as: Zhōngguó Hǎiyáng Dàxué & OUC.

Observations of the vertical distributions of summertime atmospheric pollutants and the corresponding ozone production in Shanghai, China

Abstract: . Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) and lidar measurements were performed in Shanghai, China, during May 2016 to investigate the vertical distribution of summertime atmospheric pollutants. In this study, vertical profiles of aerosol extinction coefficient, nitrogen dioxide (NO2) and formaldehyde (HCHO) concentrations were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm, while vertical distribution of ozone (O3) was obtained from an ozone lidar. Sensitivity study of the MAX-DOAS aerosol profile retrieval shows that the a priori aerosol profile shape has significant influences on the aerosol profile retrieval. Aerosol profiles retrieved from MAX-DOAS measurements with Gaussian a priori profile demonstrate the best agreements with simultaneous lidar measurements and vehicle-based tethered-balloon observations among all a priori aerosol profiles. Tropospheric NO2 vertical column densities (VCDs) measured with MAX-DOAS show a good agreement with OMI satellite observations with a Pearson correlation coefficient (R) of 0.95. In addition, measurements of the O3 vertical distribution indicate that the ozone productions do not only occur at surface level but also at higher altitudes (about 1.1 km). Planetary boundary layer (PBL) height and horizontal and vertical wind field information were integrated to discuss the ozone formation at upper altitudes. The results reveal that enhanced ozone concentrations at ground level and upper altitudes are not directly related to horizontal and vertical transportation. Similar patterns of O3 and HCHO vertical distributions were observed during this campaign, which implies that the ozone productions near the surface and at higher altitudes are mainly influenced by the abundance of volatile organic compounds (VOCs) in the lower troposphere.

Inhibitory effects of 5-hydroxy polymethoxyflavones on colon cancer cells.

Abstract: Hydroxylated polymethoxyflavones (PMFs) are a class of novel flavonoid compounds mainly found in citrus plants. We studied the effects of three major 5-hydroxy PMFs, namely: 5-hydroxy-6,7,8,3 0 ,4 0 -pentamethoxyflavone, 5-hydroxy-3,6,7,8,3 0 ,4 0 -hexamethoxyflavone, and 5-hydroxy-6,7,8,4 0 -tetramethoxyflavone, on human colon cancer HCT116 and HT29 cells. Their effects were compared with those produced by their permethoxylated counterparts, namely: nobiletin, 3,5,6,7,8,3 0 ,4 0 -heptamethoxylflavone, and tangeretin. 5-Hydroxy PMFs showed much stronger inhibitory effects on the growth of the colon cancer cells in comparison with their permethoxylated counterparts, suggesting the pivotal role of hydroxyl group at 5-position in the enhanced inhibitory activity by 5-hydroxy PMFs. Flow cytometry analysis demonstrated that three 5-hydroxy PMFs produced different effects on the cell cycle and apoptosis, which may suggest that three 5-hydroxy PMFs act through different mechanisms. For example, 5-hydroxy-6,7,8,3 0 ,4 0 pentamethoxyflavone caused cell cycle arrest at G2/M phase in HT29 cells, while 5-hydroxy3,6,7,8,3 0 ,4 0 -hexamethoxyflavone led to significant G0/G1 phase arrest. In contrast, 5-hydroxy6,7,8,4 0 -tetramethoxyflavone increased sub-G0/G1 cell population, which has been confirmed to be due to enhanced apoptosis. Our results further demonstrated that the inhibitory effects of 5hydroxy PMFs were associated with their ability in modulating key signaling proteins related to cell proliferation and apoptosis, such as p21 Cip1/Waf1 ,C DK-2, CDK-4, phosphor-Rb, Mcl-1, caspases 3 and 8, and poly ADP ribose polymerase (PARP).