The formation of (bi)carbonates is a pressing issue for CO2 electroreduction in neutral or alkaline solutions. It adversely causes low single-pass conversion efficiency as a result of (bi)carbonate crossover, as well as limited device lifetimes as a result of (bi)carbonate precipitation at the cathode. One emerging solution to circumvent this challenge is conducting the reaction in acids. To this end, we here demonstrate an acid-fed membrane electrode assembly (MEA) for CO2 electroreduction to CO. A diluted electrolyte with an H+ to Cs+ ratio of 1:1 and a relatively low current density are optimal conditions to achieve high CO Faradaic efficiencies. A relatively high H+ versus Cs+ ratio offers high electrocatalytic activities. By systematically evaluating the impact of H+ and Cs+ concentration on the electrochemical performance, we uncover the essential role of the balance between the rates of (bi)carbonate formation and H+ diffusion in determining the selectivity and activity. As a result, we report a CO partial current density of ∼105 mA cm–2 at an ∼4 V cell voltage, a near-doubled activity toward CO compared to a neutral MEA at a similar voltage. Under the optimal conditions for long-term operation, our acid-fed membrane electrode assembly is capable of delivering a CO Faradaic efficiency of ∼80%, an extraordinary single-pass conversion efficiency of ∼90% (about twice that of neutral MEA), and a 50 h long-term stability notably superior to those in previous reports.

OBJECTIVE:Although hepatitis B recurrence after liver transplantation has been reduced to 0%-10% since the application of the combination therapy of hepatitis B immunoglobulin (HBIG) and lamivudine, the viral mutation resistance of lamivudine is still an obstacle to the outcome of liver transplantation. Here we evaluate the role of entecavir in preventing hepatitis B recurrence after liver transplantation. METHODS:Patients who received a liver transplantation for hepatitis B virus (HBV)-related end-stage liver disease in our center from March 2006 to December 2008 were enrolled in this study. All patients received entecavir (0.5 mg orally, daily) or lamivudine (100 mg orally, daily) together with a long-term low dosage of HBIG to prevent hepatitis B recurrence after transplantation. Serum viral markers (HBsAg, antiHBs, HBeAg, anti-HBc and anti-HBe) and HBV-DNA level were determined. RESULTS:Thirty patients receiving entecavir and 90 patients receiving lamivudine were matched with the same age and sex in both groups. No reinfection of hepatitis B was detected in the entecavir group. The hepatitis B surface antigen of patients in the entecavir group became negative within one week and no patient had any adverse effect relating to entecavir. There was no difference in the cumulative survival rate between the entecavir group and the lamivudine group (P > 0.05). CONCLUSION:This study shows that entecavir combined with low dosages of HBIG is effective and safe in preventing hepatitis B recurrence after liver transplantation, but its long-term effect is still under investigation and a large-sample study will be carried out in the future.

BACKGROUND: Sequencing cell-free DNA in maternal plasma is an effective noninvasive prenatal testing technique that has been used in fetal aneuploidy screening worldwide. However, its clinical application is limited by the low fetal fraction (<4%) of cell-free DNA in many singleton pregnancies, which usually results in screen failures or no calls. In addition, dizygotic twin contributions of cell-free DNA into the maternal circulation can vary by 2-fold, complicating the quantitative diagnosis of fetal aneuploidy. OBJECTIVE: We performed semiconductor sequencing of shorter fragments (107e145 bp) of circulating cell-free DNA to improve the fetal DNA fraction at lower uniquely mapped reads (1e8.5 MB) to reduce the probability of no calls. STUDY DESIGN: We identified 2903 plasma samples from pregnant women, including 86 dizygotic twin pregnancy, that were collected at a single prenatal diagnostic center between October 2015 and July 2018. Size-selection noninvasive prenatal testing for fetal aneuploidy was applied to 2817 plasma samples (1409 male and 1408 female fetuses) and 86 dizygotic twins using noninvasive prenatal testing with and without size selection. Shorter fragment size was the key factor affecting fetal fraction in multivariable linear regression models as well as to validate the accuracy of the size selection for noninvasive prenatal testing. RESULTS: Analysis of 1409 male fetuses by multivariable linear regression showed that maternal age, body mass index, number of pregnancies, average cell-free DNA size, maternal plasma cell-free DNA concentration, library concentration, and multiple gestation were negatively correlated with fetal fraction. Conversely, gestational age and uniquely mapped reads were positively correlated with fetal fraction. Compared with 120 bp cell-free DNA fragments, mean fetal fraction differences were e3.57% (95% confidence interval, e5.95% to e1.19%), for 121e130 bp, e9.52% (95% confidence interval, e11.89% to e7.14%) for 131e140 bp, and e14.47% (95% confidence interval, e18.37% to e10.58%) for 141 bp (P trend < .0001). These results were statistically significant after multivariable adjustments in models for fetal fraction. Meanwhile, results from 86 dizygotic twins showed that the size selection increased the fetal fraction by w3.2-fold, with 98.8% of samples reaching a fetal fraction >10%. Improved detection accuracy was also achieved. CONCLUSION: Sequencing shorter cell-free DNA fragments is a reasonable strategy to reduce the probability of no calls results because of low fetal fraction and should be recommended to pregnant subjects.

Objective: The purpose of this study was to investigate the effects and pharmacological mechanisms of icariin, which is the main component in the traditional Chinese herb Epimedium, on β-amyloid (Aβ) production in an amyloid precursor protein (APP) transgenic (Tg) mouse model of Alzheimer's disease (AD).Methods: APPV717I Tg mice were randomly divided into a model group and icariin-treated (30 and 100 μmol/kg per day) groups. Learning-memory abilities were determined by Morris water maze and object recognition tests. Aβ contents were measured by enzyme-linked immunosorbent assays and immunohistochemistry. Amyloid plaques were detected by Congo red staining and Bielschowsky silver staining. The levels of expression of APP and β-site APP-cleaving enzyme 1 (BACE-1) were measured by western blotting and immunohistochemistry.Results: Ten-month-old Tg mice showed obvious learning-memory impairments, and significant increases in Aβ contents, amyloid plaques, and APP and BACE-1 levels in the hippocampus. The intragastric administration of icariin to Tg mice for 6 months (from 4 to 10 months of age) improved the learning-memory abilities and significantly decreased the Aβ contents, amyloid plaques, and APP and BACE-1 levels in the hippocampus.Conclusion: Icariin reduced the Aβ burden and amyloid plaque deposition in the hippocampus of APP transgenic mice by decreasing the APP and BACE-1 levels. These novel findings suggest that icariin may be a promising treatment in patients with AD.

Artificial synapses that integrate functions of sensing, memory and computing are highly desired for developing brain-inspired neuromorphic hardware. In this work, an optoelectronic synapse based on the ZnO nanowire (NW) transistor is achieved, which can be used to emulate both the short-term and long-term synaptic plasticity. Synaptic potentiation is present when the device is stimulated by light pulses, arising from the light-induced O2 desorption and the persistent photoconductivity behavior of the ZnO NW. On the other hand, synaptic depression occurs when the device is stimulated by electrical pulses in dark, which is realized by introducing a charge trapping layer in the gate dielectric to trap carriers. Simulation of a neural network utilizing the ZnO NW synapses is carried out, demonstrating a high recognition accuracy over 90% after only 20 training epochs for recognizing the Modified National Institute of Standards and Technology digits. The present nanoscale optoelectronic synapse has great potential in the development of neuromorphic visual systems.