Two-Terminal Lithium-Mediated Artificial Synapses with Enhanced Weight Modulation for Feasible Hardware Neural Networks

Recently,artificial synapses involving an electrochemical reaction of Li-ion have been attributed to have remarkable synaptic properties.Three-terminal synaptic transistors utilizing Li-ion intercalation exhibits reliable synaptic characteristics by exploiting the advantage of nondistributed weight updates owing to stable ion migrations.However,the three-terminal configurations with large and complex structures impede the crossbar array implementation required for hardware neuromorphic systems.Meanwhile,achieving adequate synaptic performances through effective Li-ion intercalation in vertical two-terminal synaptic devices for array integration remains challenging.Here,two-terminal Au/LixCoO_(2)/Pt artificial synapses are proposed with the potential for practical implementation of hardware neural networks.The Au/LixCoO_(2)/Pt devices demonstrated extraordinary neuromorphic behaviors based on a progressive dearth of Li in LixCoO_(2)films.The intercalation and deintercalation of Li-ion inside the films are precisely controlled over the weight control spike,resulting in improved weight control functionality.Various types of synaptic plasticity were imitated and assessed in terms of key factors such as nonlinearity,symmetricity,and dynamic range.Notably,the LixCoO_(2)-based neuromorphic system outperformed three-terminal synaptic transistors in simulations of convolutional neural networks and multilayer perceptrons due to the high linearity and low programming error.These impressive performances suggest the vertical two-terminal Au/LixCoO_(2)/Pt artificial synapses as promising candidates for hardware neural networks.

Sex-specific Cutoff Values of Visceral Fat Area for Lean vs. Overweight/Obese Nonalcoholic Fatty Liver Disease in Asians

Background and Aims:Visceral obesity is a risk factor for nonalcoholic fatty liver disease(NAFLD).We investigated sex-specific optimal cutoff values for visceral fat area(VFA)associated with lean and overweight/obese NAFLD in an Asian population.Methods:This retrospective study includ-ed 678 potential living liver donors(mean age,30.8±9.4 years;434 men and 244 women)who had undergone ab-dominal computed tomography(CT)imaging and liver bi-opsy between November 2016 and October 2017.VFA was measured using single-slice abdominal CT.NAFLD was eval-uated by liver biopsy(≥5%hepatic steatosis).Receiver op-erating characteristic curve analysis was used to determine cutoff values for VFA associated with lean(body mass index[BMI]<23 kg/m2)and overweight/obese(BMI≥23 kg/m2)NAFLD.Results:Area under the curve(AUC)values with 95%confidence intervals(CI)for VFA were 0.82(95%CI,0.75-0.88)for lean and 0.74(95%CI,0.69-0.79)for over-weight/obese men with NAFLD.The AUC values were 0.67(95%CI,0.58-0.75)for lean and 0.71(95%CI,0.62-0.80)for overweight/obese women with NAFLD.The cutoff values for VFA associated with lean NAFLD were 50.2 cm2 in men and 40.5 cm2 in women.The optimal cutoff values for VFA associated with overweight/obese NAFLD were 100.6 cm2 in men and 68.0 cm2 in women.Conclusions:Sex-specific cutoff values for VFA may be useful for identifying subjects at risk of lean and overweight/obese NAFLD.

Two distinct stem cell-like subtypes of hepatocellular carcinoma with clinical significance and their therapeutic potentials

Dear Editor Hepatocellular carcinoma(HCC)is among the most com-mon cancers worldwide,causing about 600,000 deaths annully[1].In HCC,stem cell-like characteristics,which drive early recurrence and therapy resistance,are major contributors to poor prognosis[2].In this current study,we integrated and analyzed gene expression data from human fetal liver cells and primary HCC tumors(n=1231)and.uncovered two clinically and biologically distinct hepatic stem cell(HS)subtypes,potential biomarkers associated with these subtypes,and a potential new therapeutic inter-vention for these subtypes.