RESUMEN
To enhance the performance of transition metal chalcogenide composite electrode material, a key point is a composite design and preparation based on the synergistic effect between the oxide and selenide materials. With a facile 'one step template-annealing' step, Ni3Se4, Ni0.6Zn0.4O and ZnO are simultaneously synthesized, by 500 °C annealing. With the increase of annealing temperature from 350 °C to 600 °C, nickel selenides change from NiSe2to Ni3Se4to NiSe. The charge storage capacity increases first and then decreases with the increase of annealing temperature, and the 500 °C annealing obtained three compound composite Ni3Se4/Ni0.6Zn0.4O/ZnO (NNZ-500) nanoparticle material displayed a high specific capacitance of 1089.2 F g-1at 1 A g-1, and excellent cycle stability of 99.8% capacitance retention after 2000 cycles at 5 A g-1. Moreover, an asymmetric supercapacitor was assembled with NNZ-500 as the positive electrode material and activated carbon as the negative electrode material. This kind of asymmetric supercapacitor demonstrated a high energy density of 53.4 Wh kg-1at 819.0 W kg-1, and cycle stability with 98.6% capacitance retention after 2000 cycles. This material preparation approach provides great potential for the future development of high performance transition metal composite electrode materials in energy storage applications.
RESUMEN
OBJECTIVE: To analyze the correlation between expression of miR-155 in colon cancer tissue and serum carcinoembryonic antigen (CEA) levels, and then explore its contribution to forecasting recurrence and metastasis. METHODS: Eighty-four pairs of colon cancer specimens and their corresponding non-tumor adjacent tissues were collected and analyzed between March 2009 and December 2011 in Xiangyang Central Hospital, Xiangyang, Hubei, China. The expression of miR-155 in both tissues was tested using reverse transcription-polymerase chain reaction (RT-PCR), the preoperative serum CEA level was assessed, and the postoperative serum CEA level was also assessed bimonthly during the follow-up period of 2 years. RESULTS: The expression of miR-155 in colon cancer tissue was significantly higher than that in normal tissues (p<0.05), it had an obvious positive correlation with the preoperative serum CEA levels (p<0.01), and a negative correlation with time of duration since the serum CEA level increased again postoperatively (p<0.01). The expression of miR-155 in the recurrence and metastasis group was significantly higher (6.06+/-3.73 times) than that in the non-recurrence and non-metastasis group (p<0.05). An increase in the postoperative serum CEA levels was significantly correlated with recurrence and metastasis of the tumor postoperatively. CONCLUSION: The expression of miR-155 is up-regulated in colon cancer tissue. A combination of miR-155 level assay in colon cancer tissue and the serum CEA level both pre- and postoperatively can afford more accurate information for diagnosis and prognosis, especially for predicting recurrence and metastasis postoperatively.