[Experimental study on the stimulation effect of temperature and capsaicin on oral mucosa of rats].

PURPOSE: This study evaluated the effect of hot etching with two acid solutions on the surface topography and bond strength of zirconia. METHODS: Firstly, twenty-four pieces of zirconia with a size of 10 mm×10 mm×2 mm and 20 pieces of zirconia with a size of 3 mm×3 mm×2 mm were prepared. Then pieces were divided into four groups, and dealt with separately according to the following groups: no treatment (group A), sandblasting (group B), hot etching with HCl(group C), hot etching with HF(group D). Finally, the surface topography and bond strength were tested by atomic force microscopy(AFM), scanning electron microscope(SEM), X-ray diffraction(XRD) and universal testing machine, etc. Statistical analysis of the experimental data was performed with SPSS 26.0 software package. The final results of XRD were analyzed using MDI Jade 6 combined with Origin 2019 software. RESULTS: Groups C and D produced completely different topographical changes on the surface of zirconia than group B. Obvious interfacial cracks were observed in group B. Group D achieved the highest roughness value (78.17±4.94) nm and highest shear bond strength (25.09±4.09) MPa. CONCLUSIONS: Compared with HCl, hot etching with HF could achieve more uniform and dense porous morphology, greater roughness and shear bond strength. There were no obvious cross-section interfacial cracks and crystal phase transformations on the surface of zirconia.

[Column-integrated Aerosol Optical Properties Determined Using Ground-based Sun Photometry Measurements in the Hangzhou Region].

To investigate the optical properties of aerosols in the Hangzhou region (Hangzhou, Tonglu, Jiande, and Chun'an), the aerosol optical depth (AOD), Ångström exponent (AE), single scattering albedo (SSA), and aerosol size distribution (ASD) were measured using CIMEL sun-photometers in 2012. The results showed that the annual average values of AOD440nm in Hangzhou, Tonglu, Jiande, and Chun'an were 0.94±0.16, 0.84±0.17, 0.82±0.22, and 0.71±0.20, respectively. The values generally decreased from the northeast to the southwest, and represented one of highest AOD districts in the Yangtze River Delta, China. The annual average values of AE440-870nm were 1.24±0.12, 1.19±0.17, 1.06±0.04, and 1.04±0.10, respectively, indicating that particles with small average effective radii were predominant. The relatively lower AE values in March and April were generally attributed to the long-range transport of dust aerosols from Northwest China. Obvious diurnal variations in the AOD were found in Hangzhou, Tonglu, and Jiande, but not in Chun'an. An average fine-mode effective radius of~0.15 µm was observed in spring, autumn, and winter, while a value of~0.25 µm was observed in summer, in conjunction with aerosol hygroscopic growth. An average coarse-mode effective radius of~2.94 µm was observed in summer, autumn, and winter, which was higher than the value in spring. The annual average values of SSA440nm were 0.91±0.01, 0.92±0.03, 0.92±0.02, 0.93±0.02, respectively, indicating that the particles had relatively strong to moderate absorption. Characterization of the aerosol types showed the predominance of biomass burning and urban industrial type aerosols in Hangzhou, while mixed type aerosols were observed in Tonglu, Jiande, and Chun'an.