Flexible full two-dimensional memristive synapses of graphene/WSe2-xOy/graphene.

van der Waals heterostructures realized by stacking different two-dimensional materials offer the possibility to design new devices with atomic-level precision. The realization of memristive synapses based on full two-dimensional materials provides an avenue for developing neuromorphic computing systems with excellent mechanical flexibility in future. Herein, we first develop the flexible full two-dimensional memristive synapse of graphene/WSe2-xOy/graphene exhibiting stable volatile resistive switching. The oxidation of WSe2 through O2 plasma treatment plays a key role in improving the memristive performance of the devices. And the switching behavior is associated with the migration of oxygen vacancies at the graphene/WSe2-xOy interface. Versatile synaptic functions have been realized, including short-term plasticity, long-term plasticity, the transition from short-term plasticity to long-term plasticity and high-pass temporal filtering, with ultralow energy consumption of ∼16.1 pJ per spike. The flexible full two-dimensional devices fabricated on flexible polyimide substrate show excellent mechanical flexibility, including a good endurance against repeatable bending of 1000 times and a bending strain of 2.5%.

X-rays induced IL-8 production in lung cancer cells via p38/MAPK and NF-κB pathway.

PURPOSE: It is reported inflammatory cytokine interleukin-8 (IL-8) could predict radiation-induced lung toxicity (RILT). RILT is believed to be a consequence of a cascade of cytokine production. It is considered that vascular endothelial cell and macrophages are the mainly source of cytokines. This study was investigated the production of IL-8 from cancer cells induced by X-rays may involve in the radiation-induced inflammation. MATERIALS AND METHODS: We analyzed IL-8 in human lung cancer cell lines after expose to X-rays, and we also detect IL-8 in HUVEC cells and THP1 cells as endothelial cell and macrophage model to identify the change in normal cells after expose. Furthermore, we added the inhibitors to the culture with or without radiation to identify the role of MAPK and NF-κB pathways on the radiation-induced secretion of IL-8. RESULTS: Radiation could induce IL-8 production both in non-lung cancer cells (HUVECs and THP1 cells) and in lung cancer cells (A549 cells, H446 cells, PC-9 cells). Simultaneously, radiation activated p38/MAPK and NF-κB signal pathways in lung cancer cells. Moreover, p38/MAPK inhibitor SB203580 and NF-κB inhibitor BAY11-7082 could block the IL-8 up-regulated by X-rays but JNK inhibitor SP600125, ERK inhibitor U0126, ROS Scavenger NAC could not inhibit this phenomenon. CONCLUSIONS: X-rays could induce IL-8 production in lung cancer cells, which may be related to the activation of p38/MAPK and NF-κB signaling pathway, providing a new point for elucidating the mechanism of radiation pneumonitis.

Multi-gate memristive synapses realized with the lateral heterostructure of 2D WSe2 and WO3.

The development of novel synaptic device architectures with a high order of synaptic plasticity can provide a breakthrough toward neuromorphic computing. Herein, through the thermal oxidation of two-dimensional (2D) WSe2, unique memristive synapses based on the lateral heterostructure of 2D WSe2 and WO3, with multi-gate modulation characteristics, are firstly demonstrated. An intermediate transition layer in the heterostructure is observed through transmission electron microscopy. Raman spectroscopy and detailed electrical measurements provide insights into the mechanism of memristive behavior, revealing that the protons injected into/removed from the intermediate transition layer account for the memristive behavior. This novel memristive synapse can be used to emulate two neuron-based synaptic functions, like post-synaptic current, short-term plasticity and long-term plasticity, with remarkable linearity, symmetry, and an ultralow energy consumption of ∼2.7 pJ per spike. More importantly, the synaptic plasticity between the drain and source electrodes can be effectively modulated by the gate voltage and visible light in a four-terminal configuration. Such multi-gate tuning of the synaptic plasticity cannot be accomplished by any previously reported multi-gate synaptic devices that only mimic two neuron-based synapses. This new synaptic architecture with electrical and optical modulation enables a realistic emulation of biological synapses whose synaptic plasticity can be additionally regulated by the surrounding astrocytes, greatly improving the recognition accuracy and processing capacity of artificial neuristors, and paving a new way for highly efficient neuromorphic computation devices.