Converting low-grade waste heat into usable electricity and storing it simultaneously requires a new technology that realize the directional migration of electrons or ions under temperature difference and enrichment o...Converting low-grade waste heat into usable electricity and storing it simultaneously requires a new technology that realize the directional migration of electrons or ions under temperature difference and enrichment on the electrodes.Although the urgent demand of energy conversion-storage(ECS)has emerged in the field of wearable electronic,achieving the integrated bi-functional device remains challenge due to the different mechanisms of electrical transportation and storage.Here,we report an ionic thermoelectric supercapacitor that relies on the synergistic functions of thermoelectricity and supercapacitor in the thermoelectric ionogel electrolyte and high-performance hydrogel electrodes to enhance the ECS performance under a thermal gradient.The thermoelectric electrolyte is composed of polyacrylamide hydrogel and sodium carboxymethyl cellulose(PMSC),possessing cross-linked network with excellent cation selectivity,while the ionic thermoelectric properties are further improved in the presence of NaCl.The corresponding Seebeck coefficient and ionic conductivity of the NaCl–PMSC electrolyte reach 17.1 mV K^(-1)and 26.8 mS cm^(-1),respectively.Owing to good stretchability of both gel-based electrolyte and electrode,the fullstretchable integrated ECS device,termed ionic thermoelectric supercapacitor,presents promising thermal-charge storage capability(~1.3 mC,ΔT≈10 K),thus holds promise for wearable energy harvesting.展开更多
With the development of the Internet of Things,the edge devices are increasing.Cyber security issues in edge computing have also emerged and caused great concern.We propose a defense strategy based on Mean field game ...With the development of the Internet of Things,the edge devices are increasing.Cyber security issues in edge computing have also emerged and caused great concern.We propose a defense strategy based on Mean field game to solve the security issues of edge user data during edge computing.Firstly,an individual cost function is formulated to build an edge user data security defense model.Secondly,we research the𝜀𝜀-Nash equilibrium of the individual cost function with finite players and prove the existence of the optimal defense strategy.Finally,by analyzing the stability of edge user data loss,it proves that the proposed defense strategy is effective.展开更多
Genetic modification of large DNA fragments(gene clusters) is of great importance in synthetic biology and combinatorial biosynthesis as it facilitates rational design and modification of natural products to increase ...Genetic modification of large DNA fragments(gene clusters) is of great importance in synthetic biology and combinatorial biosynthesis as it facilitates rational design and modification of natural products to increase their value and productivity.In this study,we developed a method for scarless and precise modification of large gene clusters by using RecET/RED-mediated polymerase chain reaction(PCR) targeting combined with Gibson assembly.In this strategy,the biosynthetic genes for peptidyl moieties(HPHT) in the nikkomycin biosynthetic gene cluster were replaced with those for carbamoylpolyoxamic acid(CPOAA)from the polyoxin biosynthetic gene cluster to generate a^40 kb hybrid gene cluster in Escherichia coli with a reusable targeting cassette.The reconstructed cluster was introduced into Streptomyces lividans TK23 for heterologous expression and the expected hybrid antibiotic,polynik A,was obtained and verified.This study provides an efficient strategy for gene cluster reconstruction and modification that could be applied in synthetic biology and combinatory biosynthesis to synthesize novel bioactive metabolites or to improve antibiotic production.展开更多
Dear Editor,Streptomyces can produce a large variety of secondary metabolites as a major source of anti-infective, antitumor or immune-suppressive agents widely applied in clinical treatment. Antibiotics-resistant bac...Dear Editor,Streptomyces can produce a large variety of secondary metabolites as a major source of anti-infective, antitumor or immune-suppressive agents widely applied in clinical treatment. Antibiotics-resistant bacteria are spreading at alarming rates.展开更多
基金financial support by the National Natural Science Foundation of China(No.51873033 and No.52073057)the Fundamental Research Funds for the Central Universities(2232020A-01 and 2232019A3-02)+3 种基金DHU Distinguished Young Professor Program(LZB2019002)Shanghai Rising-Star Program(20QA1400300)the Fundamental Research Funds for the Central University and Graduate Student Innovation Fund of Donghua University(CUSFDH-D-2020033)State Key Laboratory for Space Power Sources Technology(No.YF07050117F0768)。
文摘Converting low-grade waste heat into usable electricity and storing it simultaneously requires a new technology that realize the directional migration of electrons or ions under temperature difference and enrichment on the electrodes.Although the urgent demand of energy conversion-storage(ECS)has emerged in the field of wearable electronic,achieving the integrated bi-functional device remains challenge due to the different mechanisms of electrical transportation and storage.Here,we report an ionic thermoelectric supercapacitor that relies on the synergistic functions of thermoelectricity and supercapacitor in the thermoelectric ionogel electrolyte and high-performance hydrogel electrodes to enhance the ECS performance under a thermal gradient.The thermoelectric electrolyte is composed of polyacrylamide hydrogel and sodium carboxymethyl cellulose(PMSC),possessing cross-linked network with excellent cation selectivity,while the ionic thermoelectric properties are further improved in the presence of NaCl.The corresponding Seebeck coefficient and ionic conductivity of the NaCl–PMSC electrolyte reach 17.1 mV K^(-1)and 26.8 mS cm^(-1),respectively.Owing to good stretchability of both gel-based electrolyte and electrode,the fullstretchable integrated ECS device,termed ionic thermoelectric supercapacitor,presents promising thermal-charge storage capability(~1.3 mC,ΔT≈10 K),thus holds promise for wearable energy harvesting.
文摘With the development of the Internet of Things,the edge devices are increasing.Cyber security issues in edge computing have also emerged and caused great concern.We propose a defense strategy based on Mean field game to solve the security issues of edge user data during edge computing.Firstly,an individual cost function is formulated to build an edge user data security defense model.Secondly,we research the𝜀𝜀-Nash equilibrium of the individual cost function with finite players and prove the existence of the optimal defense strategy.Finally,by analyzing the stability of edge user data loss,it proves that the proposed defense strategy is effective.
基金supported by grants from the Ministry of Science and Technology of China(2013CB734001 and 2015CB150600)the National Natural Science Foundation of China(31370097 and 31571281)
文摘Genetic modification of large DNA fragments(gene clusters) is of great importance in synthetic biology and combinatorial biosynthesis as it facilitates rational design and modification of natural products to increase their value and productivity.In this study,we developed a method for scarless and precise modification of large gene clusters by using RecET/RED-mediated polymerase chain reaction(PCR) targeting combined with Gibson assembly.In this strategy,the biosynthetic genes for peptidyl moieties(HPHT) in the nikkomycin biosynthetic gene cluster were replaced with those for carbamoylpolyoxamic acid(CPOAA)from the polyoxin biosynthetic gene cluster to generate a^40 kb hybrid gene cluster in Escherichia coli with a reusable targeting cassette.The reconstructed cluster was introduced into Streptomyces lividans TK23 for heterologous expression and the expected hybrid antibiotic,polynik A,was obtained and verified.This study provides an efficient strategy for gene cluster reconstruction and modification that could be applied in synthetic biology and combinatory biosynthesis to synthesize novel bioactive metabolites or to improve antibiotic production.
基金supported by grants from the Ministry of Science and Technology of China (2015CB150600)the National Natural Science Foundation of China (31571281 and 31771378)
文摘Dear Editor,Streptomyces can produce a large variety of secondary metabolites as a major source of anti-infective, antitumor or immune-suppressive agents widely applied in clinical treatment. Antibiotics-resistant bacteria are spreading at alarming rates.