RESUMO
The fabrication of type II heterojunctions is an efficient strategy to facilitate charge separation in photocatalysis. Here, mixed dimensional 0D/2D van der Waals (vdW) heterostructures (graphene quantum dots (GQDs)-MoS2) for generating hydrogen from water splitting are investigated based on density functional theory (DFT). The electronic and photocatalytic properties of three heterostructures, namely, C6H6-MoS2, C24H12-MoS2 and C32H14-MoS2 are estimated by analyzing the density of states, charge density difference, work function, Bader charge, absorption spectra and band alignment. The results indicated that the built-in electric fields from GQDs to MoS2 boost charge separation. Meanwhile, all the GQDs-MoS2 exhibit strong absorption in the visible light region. Surprisingly, the transition of heterojunctions from type I to type II is realized by tuning the size of GQDs. In particular, C32H14-MoS2 with enhanced visible-light absorption and an appropriate band edge position, as a type II heterostructure, may be a promising photocatalyst for generating hydrogen from water splitting. Thus, in this work a novel type II 0D/2D nanocomposite as a photocatalyst is constructed that provides a strategy to regulate the type of heterostructure from the perspective of theoretical calculation.
RESUMO
OBJECTIVE: To evaluate the feasibility and efficacy of intraperitoneal chemotherapy for malignant ascites caused by different types of abdominal cancers guided by chemo-sensitivity methyl tetrojolium coloremetric (MTT) assay in vitro. METHODS: Cancer cells in the malignant ascites were collected for MTT assay to determine the chemo-sensitivity. The drug producing the highest or the second highest inhibition rate was selected for intraperitoneal chemotherapy. The correlation between the results of MTT assay and the response of malignant ascites, the clinical features, Karnofsky performance score (KPS) and prognosis were analyzed. RESULTS: MTT assay indicated that Taxotere (TXT) and Hydroxycamptothecin (HCPT) were the most effective to cancer cells in malignant ascites, and HCPT was mostly frequently used for intraperitoneal chemotherapy (56.9%). Twenty-four patients showed response by intraperitoneal chemotherapy (complete response: 7; partial response: 17) with a slightly significant correlation between the results of MTT assay and response of malignant ascites (P = 0. 014). The KPS of the responders was improved significantly (P < 0.001), and the response of malignant ascites to intraperitoneal chemotherapy was demostrated as an independent prognostic factor by multi-variate analysis in this series. CONCLUSION: In vitro chemo-sensitivity MTT assay guided intraperitoneal chemotherapy for malignant ascites is simple, effective and safe, which can improve the KPS and prognosis of the responders.
