ABSTRACT
Lithium-sulfur (Li-S) batteries have attracted great attention owing to their excellent electrochemical properties, such as the high discharge voltage of 2.3 V, specific capacity of 1675 mA h g-1 and energy density of 2600 Wh kg-1. The widely used slurry made electrodes of Li-S batteries are plagued by the serious shuttle effect and insulating nature of sulfur. Herein, a reduced graphene oxide coated porous carbon nanofiber flexible paper (rGO@S-PCNP) was fabricated and directly used as an additive-free cathode for Li-S batteries. The results show that the rGO@S-PCNP is certified to be effective at relieving the shuttle effect and improving the conductivity, thus achieving high electrochemical performance. The rGO@S-PCNP composite with a sulfur content of 58.4 wt% delivers a high discharge capacity of 623.7 mA h g-1 after 200 cycles at 0.1 C (1 C = 1675 mA g-1) with the average Coulombic efficiency of 97.1%. The excellent cyclability and high Coulombic efficiency indicate that the as-prepared rGO@S-PCNP composite paper can be a promising cathode for lithium-sulfur batteries, and is envisioned to have great potential in high energy density flexible power devices. This facile strategy brings great significance for large-scale industrial fabrication of flexible lithium-sulfur batteries.
ABSTRACT
AIMS: There has been limited information about the relations between Helicobacter pylori infection and expressions of apoptosis-related proteins p53, ASPP and iASPP in gastric cancer and precancerous lesions. METHODS: H. pylori in gastric mucosa were identified by W-S staining and rapid urease test. Expression of apoptosis-related proteins P53, ASPP2 and iASPP in the gastric tissues were determined by immunohistochemistry. RESULTS: The concentrations of H. pylori and expressions of p53 and iASPP in gastric carcinoma group and precancerous lesion group were higher than in benign gastric diseases group (P<0.05). The expressions of ASPP2 in gastric carcinoma and precancerous lesion group were lower than in benign gastric diseases group (P<0.05). The expressions of p53 and iASPP in H. pylori positive group were higher than in H. pylori negative group (P<0.05), whereas ASPP2 in H. pylori positive group were lower than in H. pylori negative group (P<0.05). CONCLUSION: There was a higher rate H. pylori infection, an increased expression of apoptosis inhibitor iASPP, and decreased expression of apoptosis stimulator ASPP2 in gastric cancer or precancerous tissues. These results suggest that H. pylori may cause gastric cancer by up-regulating iASPP and down-regulating ASPP2.
