Graphene Bridge Heterostructure Devices for Negative Differential Transconductance Circuit Applications

Two-dimensional van der Waals(2D vdW)material-based heterostructure devices have been widely studied for high-end electronic applications owing to their heterojunction properties.In this study,we demonstrate graphene(Gr)-bridge heterostructure devices consisting of laterally series-connected ambipolar semiconductor/Gr-bridge/n-type molybdenum disulfide as a channel material for field-effect transistors(FET).Unlike conventional FET operation,our Gr-bridge devices exhibit nonclassical transfer characteristics(humped transfer curve),thus possessing a negative differential transconductance.These phenomena are interpreted as the operating behavior in two series-connected FETs,and they result from the gate-tunable contact capacity of the Gr-bridge layer.Multi-value logic inverters and frequency tripler circuits are successfully demonstrated using ambipolar semiconductors with narrow-and wide-bandgap materials as more advanced circuit applications based on non-classical transfer characteristics.Thus,we believe that our innovative and straightforward device structure engineering will be a promising technique for future multi-functional circuit applications of 2D nanoelectronics.

Metabolic interplay between glycolysis and mitochondrial oxidation: The reverse Warburg effect and its therapeutic implication

Aerobic glycolysis, i.e., the Warburg effect, may contribute to the aggressive phenotype of hepatocellular carcinoma. However, increasing evidence highlights the limitations of the Warburg effect, such as high mitochondrial respiration and low glycolysis rates in cancer cells. To explain such contradictory phenomena with regard to the Warburg effect, a metabolic interplay between glycolytic and oxidative cells was proposed, i.e., the "reverse Warburg effect". Aerobic glycolysis may also occur in the stromal compartment that surrounds the tumor; thus, the stromal cells feed the cancer cells with lactate and this interaction prevents the creation of an acidic condition in the tumor microenvironment. This concept provides great heterogeneity in tumors, which makes the disease difficult to cure using a single agent. Understanding metabolic flexibility by lactate shuttles offers new perspectives to develop treatments that target the hypoxic tumor microenvironment and overcome the limitations of glycolytic inhibitors.

Fucoidan protects hepatocytes from apoptosis and inhibits invasion of hepatocellular carcinoma by up-regulating p42/44 MAPK-dependent NDRG-1/CAP43

Fucoidan is a traditional Chinese medicine suggested to possess anti-tumor effects.In this study the anti-metastatic effects of fucoidan were investigated in vitro in human hepatocellular carcinoma(HCC) cells(Huh-7 and SNU-761) under normoxic and hypoxic conditions and in vivo using a distant liver metastasis model involving injection of MH134 cells into spleen via the portal vein.Its ability to protect hepatocytes against bile acid(BA)-induced apoptosis was investigated in primary hepatocytes.Fucoidan was found to suppress the invasion of HCC cells through up-regulation of p42/44 MAPKdependent NDRG-1/CAP43 and partly,under normoxic conditions,through up-regulation of p42/44MAPK-dependent VMP-1 expression.It also significantly decreased liver metastasis in vivo.As regards its hepatoprotective effect,fucoidan decreased BA-induced hepatocyte apoptosis as shown by the attenuation of caspase-8,and-7 cleavages and suppression of the mobilization of caspase-8 and Fas associated death domain(FADD) into the death-inducing signaling complex.In summary,fucoidandisplays inhibitory effects on proliferation of HCC cells and protective effects on hepatocytes.The results suggest fucoidan is a potent suppressor of tumor invasion with hepatoprotective effects.