[en] Gallium arsenide (GaAs) nanowire array (NWA) photocathodes have unique electrical and optical properties. Based on studies about photon absorption, band structure, and electron transport properties of GaAs nanowire, a photoemission model for GaAs NWA photocathodes is established. According to the model, we simulate and analyze the photocurrent, spectral response, and absorption properties of ordered GaAs NWA photocathodes. The results present a very interesting phenomenon; the photocurrent and spectral response peak at incident angles of 20° and 30°, respectively. These special properties of NWA cathodes differentiate them from their thin film counterparts. We also analyze the effects of nanowire length and diameter on the photocurrent of NWA cathodes, and find the optimum height of the nanowires is 10 μm. This study shows that NWAs exhibit higher absorbance and excellent charge transport. Thus, GaAs NWA photocathodes are excellent candidates for electron sources. (paper)

[en] Lenvatinib is a long-awaited alternative to sorafenib for the first-line targeted therapy of patients with advanced hepatocellular carcinoma (HCC). However, resistance to lenvatinib has also become a major obstacle to improving the prognosis of HCC patients. The underlying molecular mechanisms contributing to lenvatinib resistance in HCC are largely unknown. HGF/c-MET axis activation is related to tumor progression and several hallmarks of cancer and is considered as the key contributor to drug resistance. In the present study, we focused on the role of the HGF/c-MET axis in mediating lenvatinib resistance in HCC cells. We showed that HGF reduced the antiproliferative, proapoptotic, and anti-invasive effects of lenvatinib on HCC cells with high c-MET expression but did not significantly affect HCC cells with low c-MET expression. The c-MET inhibitor PHA-665752 rescued HCC cells from HGF-induced lenvatinib resistance. Furthermore, HGF/c-MET activated the downstream PI3K/AKT and MAPK/ERK pathways and promoted epithelial–mesenchymal transition (EMT) in HCC cells. Collectively, our results suggested that combining lenvatinib treatment with a c-MET inhibitor may improve its systemic therapeutic efficacy in HCC patients with high c-MET expression.