ClC-3 promotes angiotensin II-induced reactive oxygen species production in endothelial cells by facilitating Nox2 NADPH oxidase complex formation.

Recent evidence suggests that ClC-3, a member of the ClC family of Cl- channels or Cl-/H+ antiporters, plays a critical role in NADPH oxidase-derived reactive oxygen species (ROS) generation. However, the underling mechanisms remain unclear. In this study we investigated the effects and mechanisms of ClC-3 on NADPH oxidase activation and ROS generation in endothelial cells. Treatment with angiotensin II (Ang II, 1 µmol/L) significantly elevated ClC-3 expression in cultured human umbilical vein endothelial cells (HUVECs). Furthermore, Ang II treatment increased ROS production and NADPH oxidase activity, an effect that could be significantly inhibited by knockdown of ClC-3, and further enhanced by overexpression of ClC-3. SA-ß-galactosidase staining showed that ClC-3 silencing abolished Ang II-induced HUVEC senescence, whereas ClC-3 overexpression caused the opposite effects. We further showed that Ang II treatment increased the translocation of p47phox and p67phox from the cytosol to membrane, accompanied by elevated Nox2 and p22phox expression, which was significantly attenuated by knockdown of ClC-3 and potentiated by overexpression of ClC-3. Moreover, overexpression of ClC-3 increased Ang II-induced phosphorylation of p47phox and p38 MAPK in HUVECs. Pretreatment with a p38 inhibitor SB203580 abolished ClC-3 overexpression-induced increase in p47phox phosphorylation, as well as NADPH oxidase activity and ROS generation. Our results demonstrate that ClC-3 acts as a positive regulator of Ang II-induced NADPH oxidase activation and ROS production in endothelial cells, possibly via promoting both Nox2/p22phox expression and p38 MAPK-dependent p47phox/p67phox membrane translocation, then increasing Nox2 NADPH oxidase complex formation.

[Research on Pyrolysis Process of Kevlar Fibers with Thermogravimetric Analysis coupled and Fourier Transform Infrared Spectroscopy].

Modern industrial application and technologies require materials with superior mechanical and thermal properties. Kevlar fibers have been known as fibrous materials with good properties of high strength and high decomposition temperature which have become a hot research field in recent years. The properties of fibrous materials depend on their structures and compositions. Thermal decomposition processing of the materials is of great significance for their structures and thermal properties. As a new technique, thermogravimetric (TG) analysis coupled with Fourier transform infrared spectroscopy(FTIR), are able to analyze materials not only qualitatively but also quantitatively. This method has obvious advantages in researching the thermal decomposition of many materials. However, the thermal decomposition processing of Kevlar fibers is rarely reported in the literature, therefore, we firstly studied the pyrolysis behavior of Kevlar fibers with thermogravimetric analysis coupled with Fourier transform infrared spectroscopy at the temperature of 30~800 ℃. We not only obtained the processing of the Kevlar fibers' thermal decomposition with great details but also the products of every stage. Experimental results exhibited that the decomposition of Kevlar fibers has experienced three stages： 100~240, 240~420 and 420~800 ℃. The weight loss of Kevlar fibers was quite slow before 500 ℃. The third stage was the main stage of the decomposition, and the amount of residue finally reached to a mass percent of 56.21%. FTIR analysis illustrated that free water released from Kevlar fibers at the first stage, followed by the dehydration and depolymerization which made polymer chains short. Finally the fiber fragments further reacted and produced the gases of small molecular mass, and the main products were water, ammonia, carbon monoxide and carbon dioxide. Generation rate of water was increased; the emission of ammonia was at the same rate; carbon monoxide was only produced at the temperature of 515~630 ℃, then turned into carbon dioxide. The release of carbon dioxide was on rise because of the conversion process of carbon monoxide, and then dropped to a certain value.

[Studies on relics conservation by diffuse reflectance spectroscopy].

A diffuse reflectance spectroscopic method was developed to investigate relics conservation with a self-made fiber optics reflectance spectrophotometer. With this technique (1) identifying pigments on the color relics was done by comparing the shapes of reflectance spectra and the positions of reflectance peaks or first derivative peaks with those of related standard pigments; (2) changes of surface states of metals were monitored. From the investigation on the reflectance spectra of copper and its rust product, we can easily get some information about the metal surface, so diffuse reflectance spectroscopy shows special function in the research on metal surface; (3) the diffuse reflectance spectroscopic characteristics of the materials used in protection and restoration of cultural heritages were studied, which can help us choose proper protecting and restoring materials. From our studies it was verified that diffuse reflectance spectroscopy is a quick, simple and non-destructive analytical technique. The study makes diffuse reflectance spectroscopy a new means for relic protection, and opens a new application area for diffuse reflectance spectroscopy as well.