Coronavirus disease 2019 (COVID-19

A facile and general way for the synthesis of porous and hollow complex oxides is highly desirable owing to their significant applications for energy storage and other fields. In this contribution, uniform Mn(0.33)Co(0.67)CO(3) and Co(0.33)Mn(0.67)CO(3) microspheres are firstly fabricated solvothermally just by tuning the molar ratio of Mn and Co. Subsequently, the growth of multiporous MnCo(2)O(4) and CoMn(2)O(4) quasi-hollow microspheres by topotactic chemical transformation from the corresponding precursors are realized through a non-equilibrium heat treatment process. Topotactic conversion further demonstrated that the much larger CoMn(2)O(4) pores than those of MnCo(2)O(4) are possibly due to the longer transfer distance of ions. When evaluated as anode materials for LIBs (lithium ion batteries), after 25 cycles at a current density of 200 mA g(-1), the resultant MnCo(2)O(4) and CoMn(2)O(4) quasi-hollow microspheres possessed reversible capacities of 755 and 706 mA h g(-1), respectively. In particular, the MnCo(2)O(4) samples could deliver a reversible capacity as high as 610 mA h g(-1) even at a higher current density of 400 mA g(-1) with excellent electrochemical stability after 100 cycles of testing, indicating its potential application in LIBs. We believe that such good performance results from the appropriate pore size and quasi-hollow nature of MnCo(2)O(4) microspheres, which can effectively buffer the large volume variation of anodes based on the conversion reaction during Li(+) insertion/extraction. The present strategy is simple but very effective, and due to its versatility, it can be extended to other binary, even ternary complex metal oxides with high-performance in LIBs.

The production of bioactive plant compounds using microbial hosts is considered a safe, costcompetitive and scalable approach to their production. However, microbial production of some compounds like aromatic amino acid (AAA)-derived chemicals, remains an outstanding metabolic engineering challenge. Here we present the construction of a Saccharomyces cerevisiae platform strain able to produce high levels of p-coumaric acid, an AAA-derived precursor for many commercially valuable chemicals. This is achieved through engineering the AAA biosynthesis pathway, introducing a phosphoketalose-based pathway to divert glycolytic flux towards erythrose 4-phosphate formation, and optimizing carbon distribution between glycolysis and the AAA biosynthesis pathway by replacing the promoters of several important genes at key nodes between these two pathways. This results in a maximum p-coumaric acid titer of 12.5 g L −1 and a maximum yield on glucose of 154.9 mg g −1 .

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