A comprehensive review on recent progress in aluminum-air batteries

The aluminum-air battery is considered to be an attractive candidate as a power source for electric vehicles(EVs) because of its high theoretical energy density(8100 Wh kg^(-1)), which is significantly greater than that of the state-of-the-art lithium-ion batteries(LIBs). However,some technical and scientific problems preventing the large-scale development of Al-air batteries have not yet to be resolved. In this review, we present the fundamentals, challenges and the recent advances in Al-air battery technology from aluminum anode, air cathode and electrocatalysts to electrolytes and inhibitors. Firstly, the alloying of aluminum with transition metal elements is reviewed and shown to reduce the selfcorrosion of Al and improve battery performance. Additionally for the cathode, extensive studies of electrocatalytic materials for oxygen reduction/evolution including Pt and Pt alloys, nonprecious metal catalysts, and carbonaceous materials at the air cathode are highlighted.Moreover, for the electrolyte, the application of aqueous and nonaqueous electrolytes in Al-air batteries are discussed. Meanwhile, the addition of inhibitors to the electrolyte to enhance electrochemical performance is also explored. Finally, the challenges and future research directions are proposed for the further development of Al-air batteries.

Cultivating global health professionals: evaluation of a training course to develop international consulting service competence in China

Background:China’s accelerating development and increasingly important role in global health engagement create a great demand for global health professionals including international consulting experts.This study reported the detailed development and evaluation of an international consulting training for global health workforce.Methods:Based on Kirkpatrick’s model,a mixed-methods approach was used to evaluate the effectiveness of the training.Quantitative and qualitative data on participants’reaction,learning,and application of the learned knowledge and skills were collected by a training evaluation survey at the ending of training and a follow-up interview in three months after the training.Results:Thirty-six participants attended the training and 34 of them completed quantitative investigation.The training satisfaction evaluations were positive,for which participants rated the training program highly and over 90%of them agreed with the usefulness of the training.About knowledge and skills change,participants showed improved consulting knowledge and skills from pre-to post-training(P<0.001).A total of 23 participants accepted follow-up interview,and most participants applied knowledge and skills learned from the training in their daily work or study.However,only 30.4%of participants applied their learning in the consulting program.The largest barrier of application was the lack of consulting opportunities.In addition,almost all the participants reported that they would be glad to attend more training courses in the future.Conclusion:The international consulting training program was well-received,and was feasible to improve the consulting service competence of global health professionals.According to participants’feedback,it is essential to develop and expand consulting training in the field of global health.

S型纤维异质结实现高效纯水光合成过氧化氢

太阳能驱动在纯水中生成过氧化氢(H_(2)O_(2))被认为是一种具有成本效益且环保的方法.然而,大多数光催化剂只有在存在牺牲供体的情况下才会表现出性能,从而限制了其实用性.本文通过静电纺丝辅助离子交换策略,制备出了S型纤维异质结Nb_(2)O_(5)@NiS(NONS),作为光催化产过氧化氢的催化剂.通过原位X射线光电子能谱分析研究了S型电荷转移路径.通过捕获实验和电子自旋共振光谱,证实了单线态氧(1O_(2))与H_(2)O_(2)的形成有关.这项工作还揭示了通过制造纤维异质结光催化剂产生H_(2)O_(2)的另一种反应途径.

A high-performance electrocatalyst for oxygen reduction derived from copolymer-anchored polyoxometalates

The development and synthesis of cathode electrocatalysts with high activity and durable stability for metal-air batteries is an important challenge in the area of electrocatalysis.Herein,we introduce a novel in-situ nitriding and phosphating strategy for producing W_(3)N_(4)and WP from phosphotungstic acid(HPW)-polyaniline-phytic acid-Fe3+organic-inorganic hybrid material.The final material has a three-dimensional porous framework with W_(3)N_(4)-WP heterostructures embedded in the carbon matrix(W_(3)N_(4)-WP@NPC).As-made materials exhibit exceptional electrocatalytic performance for the oxygen reduction reaction(ORR),with a diffusion-limiting current density of 6.9 mA·cm^(−2)and a half-wave potential of 0.82 V.As a Zn-air primary cathode,the W_(3)N_(4)-WP@NPC assembled battery can provide a relatively high peak power density(194.2 mW·cm^(−2)).As a Zn-air secondary air-cathode,it has great cycling stability over 500 h.This work provides a simple and efficient method for rationally designing high-performance air cathodes from copolymer-anchored polyoxometalates.

MELD or MELD-Na as a Predictive Model for Mortality Following Transjugular Intrahepatic Portosystemic Shunt Placement

Background and Aim:The model for end-stage liver disease(MELD)was originally developed to predict survival after transjugular intrahepatic portosystemic shunt(TIPS).The MELD-sodium(MELD-Na)score has replaced MELD for organ allocation for liver transplantation.However,there are limited studies to compare the MELD with MELD-Na to predict mortality after TIPS.Methods:We performed a retrospective chart review of patients who underwent TIPS placement between 2006 and 2016 at our institution.The primary outcome was mortality,and the secondary outcomes sought to assess which variables could provide prognostic information for mortality after TIPS placement.We performed receiver operating characteristic(ROC)curve analysis to assess the performance of MELD and MELD-Na.Results:There were 186 eligible patients in the analysis.The mean pre-TIPS MELD and MELD-Na were 13 and 15,respectively.Overall,mortality after TIPS was 15%at 30 days and 16.7%at 90 days.In a comparison of the areas under the ROCs for MELD and MELD-Na,MELD was superior to MELD-Na for 30-day(0.762 vs.0.709)and 90-day(0.780 vs.0.730)mortality after TIPS.The optimal cutoff score for 30-day mortality was 15(0.676–0.848)for MELD and 17(0.610–0.808)for MELD-Na,whereas the optimal cutoff score for 90-day mortality was 16(95%CI:0.705–0.855)for MELD and 17(95%CI:0.643–0.817)for MELDNa.There were 24 patients with high MELD-Na≥17,but with low MELD<15,and 90-day mortality in this group was 8.3%.Conclusions:Although MELD-Na is a superior prognostic tool to MELD for predicting overall mortality in cirrhotic patients,MELD tended to outperform MELD-Na to predict mortality after TIPS.

Hierarchical porous yolk-shell Co-N-C nanocatalysts encaged in graphene nanopockets for high-performance Zn-air battery

The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge.In this work,we innovate an approach of combining solvothermal with high-temperature pyrolysis utilizing zeolitic imidazolate framework(ZIF)-8 and ZIF-67 as the template to synthesize a novel hybrid material of hierarchical porous yolk-shell Co-N-C polyhedron nanocatalysts engaged in graphene nanopocket(yolk-shell Co-N-C@GNP).The obtained catalyst exhibits prominent bifunctional electrocatalytic performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in the alkaline condition,in which the half-wave potential is 0.86 V for ORR,and the over-potential for OER is 0.42 V at 10 mA·cm^(-2).The rechargeable aqueous Zn-air battery fabricated with yolk-shell Co-N-C@GNP cathode deliveries an open circuit voltage(OCV)of 1.60 V,a peak power density of 236.2 mW·cm^(-2),and excellent cycling stability over 94 h at 5 mA·cm^(-2).The quasi-solid-state Zn-air battery(ZAB)using yolk-shell Co-N-C@GNP displays a high OCV of 1.40 V and a small voltage gap of 0.88 V in continuous cycling tests at 2 mA·cm^(-2).This work provides a valuable thought to focus attention on the design of high-efficient bifunctional catalysts with hierarchical porous yolk-shell framework and high-density metal active sites for metal-air battery technologies.

One-step,in situ formation of WN-W_(2)C heterojunctions implanted on N doped carbon nanorods as efficient oxygen reduction catalyst for metal-air battery

Transition metal nitrides and carbides have attracted intensive attentions in metal-air battery application due to their metallic electron transport behavior and high chemical stability toward the oxygen reduction reaction(ORR).Herein,the polyoxometalate@polyaniline composite derived WN-W_(2)C heterostructured composite(WN-W_(2)C@pDC)has been fabricated through an in situ nitriding-carbonization strategy,with WN-W_(2)C nanoparticles implanted on N doped carbon nanorods.Asfabricated WN-W_(2)C@pDC demonstrates prominent electrocatalytic performance towards ORR and excellent cycling stability in metal-air battery,which possesses positive half-wave potential and large diffusion limiting current density(0.81 V and 5.8 mA·cm^(-2)).Moreover,it demonstrates high peak power density of 157.4 mW·cm^(-2)as Al-air primary cathode and excellent stability at the discharge-charge test(>500 h)of Zn-air secondary battery.The excellent activity and durability of WNW_(2)C@pDC catalyst should be attributed to the combined effect of intimate WN-W_(2)C heterointerfaces,unique embedded nanoparticles structure,and excellent electrical media of N doped carbon,confirmed by a series of contrast experiments.

Potential benefits of precise corticosteroids therapy for severe 2019-nCoV pneumonia

Dear Editor,Since last December,the outbreak of 2019-nCoV in Wuhan has caused ever-increasing attention and public panic all over the world.Up to February 9,2020,40,171 patients had been diagnosed with 2019-nCoV infection,including 6484(16.14%)severe cases and 908 deaths(2.27%).Compared to SARS and MERS,2019-nCoV appears to be much more contagious but less lethal,as most patients have mild symptoms and good prognosis1,2.However,according to the Chinese government’s daily report,13.2–21.3%of patients with 2019-nCoV infection developed into severe or fatal illness(Fig.S1a),which is characterized by the rapid development to acute respiratory distress syndrome(ARDS)or septic shock.Along with an increasing number of confirmed cases,the cumulative total of severe patients with 2019-nCoV is growing(Fig.S1b).Treatment of these critically ill patients is becoming one of the major challenges we are facing.

Structural Design Optimization Based on the Moving Baseline Strategy

Structural design optimization has always been a topic of concern in industry because good design can improve the safety and economic efficiency of structures during their service periods.Selecting the appropriate optimization algorithm is the key to solving structural optimal design problems.In this study,a new global optimization idea is proposed and named the moving baseline strategy.A baseline is initially set and will be repeatedly moving upward or downward to approach the optimal value.The proposed strategy is a simple but effective,general,and stable algorithm that can be used to solve constrained and unconstrained structural optimization problems.Different from traditional gradient-based,stochastic and heuristic algorithms,the developed algorithm provides a completely new idea to solve global or local optimization problems.Some unconstrained and constrained numerical benchmark examples are used to test the proposed methodology.In addition,structural optimal design problems of a ten-bar planar truss structure and a hypersonic wing structure(X-37B)are utilized to verify the effectiveness of the developed strategy in addressing structural design optimization problems in engineering.