Coreopsis tinctoria Nutt.,an edible flowering plant,belongs to the Chrysanthemum family and is mainly grown at high altitudes in Northwestern China.It is rich in polyphenolic compounds,particularly marein and flavomar...Coreopsis tinctoria Nutt.,an edible flowering plant,belongs to the Chrysanthemum family and is mainly grown at high altitudes in Northwestern China.It is rich in polyphenolic compounds,particularly marein and flavomarein,and possesses multiple health-promoting properties,such as antioxidant,hypoglycemic and vasorelaxant effects.Previous bioactivity investigations majorly focused on C.tinctoria and its crude extract.The aim of the present study was to prepare marein-dominant C.tinctoria flavonoids(CF),further investigate the CF protective effects of liver fibrosis induced by carbon tetrachloride and elucidate the associated molecular mechanisms.Results have demonstrated that CF effectively attenuated hepatofibrogenesis by increasing the activity of glutathione(GSH)and superoxide dismutase(SOD);suppressing the hepatic stellate cell(HSC)activation,inhibiting transforming growth factorβ(TGF-β)activation and the production ofα-smooth muscle actin(α-SMA),alleviating the phosphorylation of extracellular signal-regulated kinases1/2(ERK1/2)and small mothers against decapentaplegic1/2(Smad1/2),thus maintaining the collagen metabolic homeostasis in the liver.Our study revealed that CF possesses an efficacious protective effect against chronic hepatic fibrosis due to their strong inhibitory effects of oxidative stress and chronic inflammation.展开更多
<div style="text-align:justify;"> In recent years, multi-target tracking technology based on Gaussian Mixture- Probability Hypothesis Density (GM-PHD) filtering has become a hot field of information fu...<div style="text-align:justify;"> In recent years, multi-target tracking technology based on Gaussian Mixture- Probability Hypothesis Density (GM-PHD) filtering has become a hot field of information fusion research. This article outlines the generation and development of multi-target tracking methods based on GM-PHD filtering, and the principle and implementation method of GM-PHD filtering are explained, and the application status based on GM-PHD filtering is summarized, and the key issues of the development of GM-PHD filtering technology are analyzed. </div>展开更多
Two cross⁃sectional configurations of thin⁃walled square tubes partially filled with lightweight metallic foams are proposed,and termed as double⁃cell configuration partially filled with foam(DC⁃PF)and double⁃tube con...Two cross⁃sectional configurations of thin⁃walled square tubes partially filled with lightweight metallic foams are proposed,and termed as double⁃cell configuration partially filled with foam(DC⁃PF)and double⁃tube configuration partially filled with foam(DT⁃PF),respectively.The bending crashworthiness is investigated based on three⁃point bending tests using finite element ABAQUS/Explicit code.The two key mechanical indicators including Crash Load Efficiency(CLE)and Specific Energy Absorption(SEA)are introduced to evaluate the effect of foams in comparison with empty square tubes and fully filled square tubes.The numerical results show that the two partially filled configurations,especially DT⁃PF,display dramatically excellent bending crashworthiness compared with empty and fully filled square tubes.There exists a foam density threshold,beyond which the CLE of DT⁃PF achieves a maximum constant.In addition,there seems to be another foam density threshold,beyond which the SEA of DT⁃PF gets to the maximum value.It is also shown that the foam density threshold corresponding to the maximum SEA varies with the thickness of thin⁃walled square tubes.展开更多
Zika virus (ZIKV) is a flavivirus that can be identified as a small envelope with a positive-stranded RNA and an important medical pathogen, which causes deadly human diseases. The virus is carried by Aedes aegypti mo...Zika virus (ZIKV) is a flavivirus that can be identified as a small envelope with a positive-stranded RNA and an important medical pathogen, which causes deadly human diseases. The virus is carried by Aedes aegypti mosquitoes through a blood meal and it is also spread through body fluids. ZIKV infection may present with symptoms like fever, myalgia, maculopapular rash as well as neurological sequelae, which include, microcephaly, epilepsy, and Guillain Barré syndrome (GBS). This put the virus on a scale of the public health burden of almost 87 countries. The potential threat of ZIKV infection is not completely eradicated in many countries in Africa, America, and the Western Pacific regions. There are no vaccines and treatments available to date. Since ZIKV causes microcephaly in utero by targeting neural progenitor cells, inducing apoptosis, and impairing neurodevelopment, this article hopes to evaluate the neurological disorders associated with the Zika virus infection while elucidating the current trends in the development of vaccines and drugs.展开更多
A copper-ceria solid solution and ceria-supported copper catalysts were prepared and used for the catalytic hydrogenation of CO2 to CH3OH.According to site-specific classification and quantitative analyses(X-ray diffr...A copper-ceria solid solution and ceria-supported copper catalysts were prepared and used for the catalytic hydrogenation of CO2 to CH3OH.According to site-specific classification and quantitative analyses(X-ray diffraction,Raman spectroscopy,X-ray photoelectron spectroscopy,H2 temperature-programmed reduction,and CO adsorption),the interfaces of the prepared catalysts were classified as Cu incorporated into ceria(Cu-Ov-Cex),dispersed Cu O(D-Cu O-Ce O2),and bulk Cu O(B-Cu O-Ce O2)over the Ce O2 surface.These results,together with those of activity tests,showed that the Cu-Ov-Cex species was closely related to the CO2 hydrogenation activity and resulted in a much higher turnover frequency of CH3OH production than that observed with the D-Cu O-Ce O2 and B-Cu O-Ce O2 species.Thus,the copper-ceria solid solution exhibited improved activity due to the higher Cu-Ov-Cex fraction.展开更多
Hydrogenation of CO_(2) to value-added chemicals has attracted much attention all through the world.In2 O_(3) with cubic bixbyite-type(denoted as c-In2O_(3))is well known for its high CO_(2) hydrogenation activity and...Hydrogenation of CO_(2) to value-added chemicals has attracted much attention all through the world.In2 O_(3) with cubic bixbyite-type(denoted as c-In2O_(3))is well known for its high CO_(2) hydrogenation activity and CH3 OH selectivity at high temperature.However,the other structure of In2O_(3) with rhombohedral corundum-type(denoted as rh-In2O_(3))rarely been investigated as catalyst.Herein,c-In2O_(3) and rh-In2O_(3) were prepared and comparatively studied for CO_(2) hydrogenation.The results indicated that c-In2O_(3) showed higher CO_(2) conversion activity than rh-In2O_(3) due to the impressive reducibility and reactivity.Whereas rh-In2O_(3) had higher CH3 OH selectivity due to weaker CH3 OH and stronger CO adsorption on rhIn2O_(3).Although c-In2O_(3) and rh-In2O_(3) catalysts showed different CO_(2) hydrogenation perfo rmance,in-situ diffuse reflectance infrared Fourier transform spectroscopy showed CO_(2) can be reduced to CO through redox cycling and hydrogenation to CH3 OH through formate path.展开更多
The hydrogenation of CO_(2) into methanol has attracted much attention and In_(2)O_(3) is a promising catalyst.Introducing metal elements into In_(2)O_(3)(M/In_(2)O_(3))is one of the main strategies to improve its per...The hydrogenation of CO_(2) into methanol has attracted much attention and In_(2)O_(3) is a promising catalyst.Introducing metal elements into In_(2)O_(3)(M/In_(2)O_(3))is one of the main strategies to improve its performance.However,its mechanism and active sites remain unclear and need to be further elucidated.Here,the noble‐metal‐free In_(x)‐Co_(y) oxides catalysts were prepared.Much‐improved performance and obvious product selectivity shift were observed.The optimized catalyst(In_(1)‐Co_(4))(9.7 mmol g_(cat)^(–1) h^(–1))showed five times methanol yields than pure In_(2)O_(3)(2.2 mmol g_(cat)^(–1) h^(–1))(P=4.0 MPa,T=300°C,GHSV=24000 cm^(3)_(STP) g_(cat)^(–1) h^(–1),H_(2):CO_(2)=3).And the cobalt‐catalyzed CO_(2) methanation activity was suppressed,although cobalt was most of the metal element.To unravel this selectivity shift,detailed catalysts performance evaluation,together with several in‐situ and ex‐situ characterizations,were employed on cobalt and In‐Co for comparative study.The results indicated CO_(2) hydrogenation on cobalt and In‐Co catalyst both followed the formate pathway,and In‐Co reconstructed and generated a surface In_(2)O_(3)‐enriched core‐shell‐like structure under a reductive atmosphere.The enriched In_(2)O_(3) at the surface significantly enhanced CO_(2) adsorption capacity and well stabilized the intermediates of CO_(2) hydrogenation.CO_(2) and carbon‐containing intermediates adsorbed much stronger on In‐Co than cobalt led to a feasible surface C/H ratio,thus allowing the*CH_(3)O to desorb to produce CH_(3)OH instead of being over‐hydrogenated to CH_(4).展开更多
Electrocatalytic CO2 reduction (ECR) into value-added chemicals offers potential solution for renewable energy as well as global carbon footprint concerns. In this review we introduce the general methods and metrics t...Electrocatalytic CO2 reduction (ECR) into value-added chemicals offers potential solution for renewable energy as well as global carbon footprint concerns. In this review we introduce the general methods and metrics that are commonly applied in ECR, followed by a discussion of current reaction mechanisms and different pathways. We highlight how size and structure of electrocatalysts affect ECR performance and review recent advances in metalfree and single-atom catalysts. The challenges of ECR are also discussed and optimistic perspectives are made for future work.展开更多
In the past decade, the aprotic lithium-oxygen(Li-O_2) battery has generated a great deal of interest because theoretically it can store more energy than today's lithium-ion batteries. Although considerable resear...In the past decade, the aprotic lithium-oxygen(Li-O_2) battery has generated a great deal of interest because theoretically it can store more energy than today's lithium-ion batteries. Although considerable research efforts have been devoted to the R&D of this potentially disruptive technology, many scientific and engineering obstacles still remain to be addressed before a practical device could be realized. In this review, we summarize recent advances in the fundamental understanding of the O_2 electrochemistry in Li-O_2 batteries, including the O_2 reduction to Li_2O_2 on discharge and the reverse Li_2 O_2 oxidation on recharge and factors that exert strong influences on the redox of O_2/Li_2O_2. In addition,challenges and perspectives are also provided for the future study of Li—O_2 batteries.展开更多
Herein, we reported a new label-free and fluorescence turn-on biosensor based on cationic conjugated poly（9,9-bis（6＇-N,N,N-trimethylammonium）hexyl）fluorine phenylene）（PFP） and perylene diimide derivatives（PDI...Herein, we reported a new label-free and fluorescence turn-on biosensor based on cationic conjugated poly（9,9-bis（6＇-N,N,N-trimethylammonium）hexyl）fluorine phenylene）（PFP） and perylene diimide derivatives（PDI）. Cationic PFP, single-stranded nucleic acid and PDI were used as signal reporter, probe and fluorescence quencher, respectively. In the presence of nucleic acids, they form complexes with PFP and PDI through strong electrostatic attraction interactions, resulting in PDI aggregating on nucleic acids and fluorescence of PFP being quenched. When nucleic acids are hydrolyzed by enzymes or their conformation is changed via recognizing targets, the effective aggregation of PDI is disrupted and the quenching ability is decreased. Thus the fluorescence of PFP recovers significantly. By taking advantage of the mechanism, we construct a new biosensor for endonuclease and small molecules detection. Here, S1 nuclease and bisphenol A are used as model systems. The detection limit of the SI nuclease and BPA are1.0×10^-6U/mL and 0.05 ng/mL, respectively. Our method is sensitive, cost-effective and simple, and provides a new platform for bioanalysis.展开更多
Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related diseases.Targeted AGE inhibi...Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related diseases.Targeted AGE inhibition includes scavengers of reactive carbonyl species(RCS)such as methylglyoxal(MG),glyoxalase-1 enhancers,Nrf2/ARE pathway activators,AGE/RAGE formation inhibitors and other antiglycatng agents.Citrus flavonoids have demonstrated antioxidant and anti-inflammatory effects and are also found to be effective antiglycating agents.Herein,we reviewed the up to date progress of the antiglycation effects of citrus flavonoids and associated mechanisms.Major citrus flavonoids,hesperedin and its aglycone,hesperetin,inhibited glycation by scavenging MG forming mono-or di-flavonoid adducts with MG,enhanced the activity of glyoxase-1,activated Akt/Nrf2 signal pathway while inhibiting AGE/RAGE/NF-κB pathway,reduced the formation of Nε-(carboxylmethyl)lysine(CML)and pentosidine,inhibited aldol reductase activity and decreased the levels of fructosamine.The antiglycating activity and mechanisms of other flavonoids was also summarized in this review.In conclusion,citrus flavonoids possess effective antiglycating activity via different mechanisms,yet there are many challenging questions remaining to be studied in the near future such as in vivo testing and human study of citrus flavonoids for efficacy,effectiveness and adverse effects of citrus flavonoids as a functional food in managing high levels of AGEs and controlling AGE-induced chronic diseases,diabetic complications in particular.展开更多
Dielectric pulse capacitors are of great concerns due to the fast charge/discharge rate and high-power density over traditional counterparts.However,energy-storage capacitor in power converters typically works at a la...Dielectric pulse capacitors are of great concerns due to the fast charge/discharge rate and high-power density over traditional counterparts.However,energy-storage capacitor in power converters typically works at a large DC-biased voltage,where the energy-storge density(Wdis)and efficiency(h)will dramatically decay,thus fatally blocks its further applications.Herein,we proposed a synergistic strategy to achieve a comprehensively improved energy storage property in Bi1exNaxTiO_(3)-NaNbO_(3)based ceramics.Configuration of chemical composition optimization,A-site vacancy engineering,grain size refinement,and sample thickness reduction were designed in the ceramics.Finally,an optimum Wdis of 8.04 J/cm^(3)and an ultrahigh h of 85%was achieved for the 0.50(0.95Bi_(0.52)Na_(0.44)TiO_(3)-0.05SrZrO_(3))-0.50NaNbO_(3)composite under a breakdown strength of 630 kV/cm,along with a stable DC-biased capacitance retention.Additionally,a superior performance stability was affirmed in a wide temperature/frequency range(25-150℃and 1-100 Hz,respectively).It also exhibits an impressive ability in fatigue resistance after being subjected to up to 106 cycles,which enable it to be a suitable candidate for high energy density storage devices.展开更多
Among various efficient electrocatalysts for water splitting,CoFe and NiFe-based oxides/hydroxides are typically promising candidates thanks to their extraordinary activities towards oxygen evolution reaction (OER).Ho...Among various efficient electrocatalysts for water splitting,CoFe and NiFe-based oxides/hydroxides are typically promising candidates thanks to their extraordinary activities towards oxygen evolution reaction (OER).However,the endeavor to advance their performance towards overall water splitting has been largely impeded by the limited activities for hydrogen evolution reaction (HER).Herein,we present a CoFeNi ternary metal-based oxide (CoFeNi-O) with impressive hierarchical bimodal channel nanostructures,which was synthesized via a facile one-step dealloying strategy.The oxide shows superior catalytic activities towards both HER and OER in alkaline solution due to the alloying effect and the intrinsic hierarchical porous structure.CoFeNi-O loaded on glass carbon electrodes only requires the overpotentials as low as 230 and 278 mV to achieve the OER current densities of 10 and 100 mA·cm-2,respectively.In particular,extremely low overpotentials of 200 and 57.9 mV are sufficient enough for Ni foam-supported CoFeNi-O to drive the current density of 10 mA·cm-2 towards OER and HER respectively,which is comparable with or even better than the already-developed state-of-the-art non-noble metal oxide based catalysts.Benefiting from the bifunctionalities of CoFeNi-O,an alkaline electrolyzer constructed by the Ni foam-supported CoFeNi-O electrodes as both the anode and the cathode can deliver a current density of 10 mA·cm-2 at a fairly low cell-voltage of 1.558 V.In view of its electrocatalytic merits together with the facile and cost-effective dealloying route,CoFeNi-O is envisioned as a promising catalyst for future production of sustainable energy resources.展开更多
This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available ...This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available agents, it is hard for the single-objective and single （task）-to-single （agent） task allocation approaches to handle task allocation in such circumstances. To this end, two multi-objective coalition formation for task allocation models are proposed for disaster rescues in this paper. First, through coalition formation, the proposed models enable agents to cooperatively perform complex tasks that cannot be completed by single agent. In addition, through adjusting the weights of multiple task allocation objectives, the proposed models can employ the linear programming to generate more adaptive task allocation plans, which can satisfy different task allocation requirements in disaster rescue. Finally, through employing the multi-stage task allocation mechanism of the dynamic programming, the proposed models can handle the dynamics of tasks and agents in disaster environments. Experimental results indicate that the proposed models have good performance on coalition formation for task allocation in disaster environments, which can generate suitable task allocation plans according to various objectives of task allocation.展开更多
It is a very difficult work to sinter K_(0.5)Na_(0.5)NbO_(3)(KNN)-based materials with good reduction resistance in strong reducing atmosphere.0.945K_(0.48)Na_(0.52)Nb_(0.96)Ta_(0.04)O_(3)-0.055BaZrO_(3)+0.03ZrO_(2)+y...It is a very difficult work to sinter K_(0.5)Na_(0.5)NbO_(3)(KNN)-based materials with good reduction resistance in strong reducing atmosphere.0.945K_(0.48)Na_(0.52)Nb_(0.96)Ta_(0.04)O_(3)-0.055BaZrO_(3)+0.03ZrO_(2)+y mol%MnO(KNNT-0.055BZ+0.03Zr+yMn)ceramics sintered in reducing atmosphere were prepared successfully by conventional solid-state reaction methods.MnO dopant increases grain size at y=5-8 due to strong lattice distortion and then decreases grain size at y=9 due to much Mn4Nb2O9 accumulated at the grain boundary.MnO dopant as an excellent sintering aid can effectively reduce volatilization of alkali metal by decreasing the sintering temperature(T_(sinter)).Reducing alkali metal volatilization can greatly reduce oxygen vacancies and improve piezoelectric properties.MnO dopant can improve the anti-reduction properties.The KNNT-0.055BZ+0.03Zr+yMn ceramics aty=6-9 show outstanding anti-fatigue of unipolar piezoelectric strain under the synergistic effect of reduced oxygen vacancies due to reduced volatilization and increased grain size.Piezoelectric properties and temperature stability of KNNT-0.055BZ+0.03Zr ceramics sintered in reducing atmosphere are improved simultaneously by MnO dopant.Optimum inverse piezoelectric coefficient(d33)of ceramics at y=8 reaches up to 480 pm/V under low driving electric field E=20 kV/cm at room temperature,and its temperature stability of d33 reaches 158℃.It will be an excellent lead-free material candidate for the preparation of multilayer piezoelectric actuators co-fired with nickel electrode.展开更多
Traffic flow prediction plays an important role in intelligent transportation applications,such as traffic control,navigation,path planning,etc.,which are closely related to people's daily life.In the last twenty ...Traffic flow prediction plays an important role in intelligent transportation applications,such as traffic control,navigation,path planning,etc.,which are closely related to people's daily life.In the last twenty years,many traffic flow prediction approaches have been proposed.However,some of these approaches use the regression based mechanisms,which cannot achieve accurate short-term traffic flow predication.While,other approaches use the neural network based mechanisms,which cannot work well with limited amount of training data.To this end,a light weight tensor-based traffic flow prediction approach is proposed,which can achieve efficient and accurate short-term traffic flow prediction with continuous traffic flow data in a limited period of time.In the proposed approach,first,a tensor-based traffic flow model is proposed to establish the multi-dimensional relationships for traffic flow values in continuous time intervals.Then,a CANDECOMP/PARAFAC decomposition based algorithm is employed to complete the missing values in the constructed tensor.Finally,the completed tensor can be directly used to achieve efficient and accurate traffic flow prediction.The experiments on the real dataset indicate that the proposed approach outperforms many current approaches on traffic flow prediction with limited amount of traffic flow data.展开更多
When aprotic Li-O2 batteries recharge, the solid Li2O2 in the positive electrode is oxidized, which often exhibits a continuous or step increase in the charging potential as a function of the charging capacity, and it...When aprotic Li-O2 batteries recharge, the solid Li2O2 in the positive electrode is oxidized, which often exhibits a continuous or step increase in the charging potential as a function of the charging capacity, and its origin remains incompletely understood. Here, we report a model study of electro-oxidation of a Li2O2 film on an Au electrode using voltammetry coupled with in situ Raman spectroscopy. It was found that the charging reaction initializes at the positive electrodelLizO2 interface, instead of the previously presumed Li2O2 surface, and consists of two temporally and spatially separated Li2O2 oxidation processes, accounting for the potential rise during charging of Li-O2 batteries. Moreover, the electrode surface-initialized oxidation can disintegrate the Li2O2 film resulting in a loss of Li2O2 into electrolyte solution, which drastically decreases the charging efficiency and highlights the importance of using soluble electro-catalyst for the complete charging of Li-02 batteries.展开更多
基金funded by the grant for Evaluation of Functional Property,Processing and Utilization of Xinjiang Characteristic Plant Resources(G2023046003L)the Xinjiang Uygur Autonomous Region Outstanding Youth Science Fund project(2024D01E11)+1 种基金National Nature Science Fund of China(82060788)Hebei Natural Science Foundation(C2022204167).
文摘Coreopsis tinctoria Nutt.,an edible flowering plant,belongs to the Chrysanthemum family and is mainly grown at high altitudes in Northwestern China.It is rich in polyphenolic compounds,particularly marein and flavomarein,and possesses multiple health-promoting properties,such as antioxidant,hypoglycemic and vasorelaxant effects.Previous bioactivity investigations majorly focused on C.tinctoria and its crude extract.The aim of the present study was to prepare marein-dominant C.tinctoria flavonoids(CF),further investigate the CF protective effects of liver fibrosis induced by carbon tetrachloride and elucidate the associated molecular mechanisms.Results have demonstrated that CF effectively attenuated hepatofibrogenesis by increasing the activity of glutathione(GSH)and superoxide dismutase(SOD);suppressing the hepatic stellate cell(HSC)activation,inhibiting transforming growth factorβ(TGF-β)activation and the production ofα-smooth muscle actin(α-SMA),alleviating the phosphorylation of extracellular signal-regulated kinases1/2(ERK1/2)and small mothers against decapentaplegic1/2(Smad1/2),thus maintaining the collagen metabolic homeostasis in the liver.Our study revealed that CF possesses an efficacious protective effect against chronic hepatic fibrosis due to their strong inhibitory effects of oxidative stress and chronic inflammation.
文摘<div style="text-align:justify;"> In recent years, multi-target tracking technology based on Gaussian Mixture- Probability Hypothesis Density (GM-PHD) filtering has become a hot field of information fusion research. This article outlines the generation and development of multi-target tracking methods based on GM-PHD filtering, and the principle and implementation method of GM-PHD filtering are explained, and the application status based on GM-PHD filtering is summarized, and the key issues of the development of GM-PHD filtering technology are analyzed. </div>
基金Sponsored by National Natural Science Foundation of China (Grant Nos.12272064 and 12101086)University Natural Science Research Project of Anhui Province (Grant No.KJ2018A0481)+2 种基金Major Project of Basic Science (Natural Science) Research in Jiangsu Universities (Grant Nos.22KJA460001,23KJA580001)Changzhou Science and Technology Plan Project (Grant No.CE20235049)Changzhou Leading Innovative Talents C ultivation Project (Grant No.CQ20220092).
文摘Two cross⁃sectional configurations of thin⁃walled square tubes partially filled with lightweight metallic foams are proposed,and termed as double⁃cell configuration partially filled with foam(DC⁃PF)and double⁃tube configuration partially filled with foam(DT⁃PF),respectively.The bending crashworthiness is investigated based on three⁃point bending tests using finite element ABAQUS/Explicit code.The two key mechanical indicators including Crash Load Efficiency(CLE)and Specific Energy Absorption(SEA)are introduced to evaluate the effect of foams in comparison with empty square tubes and fully filled square tubes.The numerical results show that the two partially filled configurations,especially DT⁃PF,display dramatically excellent bending crashworthiness compared with empty and fully filled square tubes.There exists a foam density threshold,beyond which the CLE of DT⁃PF achieves a maximum constant.In addition,there seems to be another foam density threshold,beyond which the SEA of DT⁃PF gets to the maximum value.It is also shown that the foam density threshold corresponding to the maximum SEA varies with the thickness of thin⁃walled square tubes.
文摘Zika virus (ZIKV) is a flavivirus that can be identified as a small envelope with a positive-stranded RNA and an important medical pathogen, which causes deadly human diseases. The virus is carried by Aedes aegypti mosquitoes through a blood meal and it is also spread through body fluids. ZIKV infection may present with symptoms like fever, myalgia, maculopapular rash as well as neurological sequelae, which include, microcephaly, epilepsy, and Guillain Barré syndrome (GBS). This put the virus on a scale of the public health burden of almost 87 countries. The potential threat of ZIKV infection is not completely eradicated in many countries in Africa, America, and the Western Pacific regions. There are no vaccines and treatments available to date. Since ZIKV causes microcephaly in utero by targeting neural progenitor cells, inducing apoptosis, and impairing neurodevelopment, this article hopes to evaluate the neurological disorders associated with the Zika virus infection while elucidating the current trends in the development of vaccines and drugs.
文摘A copper-ceria solid solution and ceria-supported copper catalysts were prepared and used for the catalytic hydrogenation of CO2 to CH3OH.According to site-specific classification and quantitative analyses(X-ray diffraction,Raman spectroscopy,X-ray photoelectron spectroscopy,H2 temperature-programmed reduction,and CO adsorption),the interfaces of the prepared catalysts were classified as Cu incorporated into ceria(Cu-Ov-Cex),dispersed Cu O(D-Cu O-Ce O2),and bulk Cu O(B-Cu O-Ce O2)over the Ce O2 surface.These results,together with those of activity tests,showed that the Cu-Ov-Cex species was closely related to the CO2 hydrogenation activity and resulted in a much higher turnover frequency of CH3OH production than that observed with the D-Cu O-Ce O2 and B-Cu O-Ce O2 species.Thus,the copper-ceria solid solution exhibited improved activity due to the higher Cu-Ov-Cex fraction.
基金the National Natural Science Foundation of China(No.21878116)Natural Science Foundation of Hubei Province(No.2019CFA070)。
文摘Hydrogenation of CO_(2) to value-added chemicals has attracted much attention all through the world.In2 O_(3) with cubic bixbyite-type(denoted as c-In2O_(3))is well known for its high CO_(2) hydrogenation activity and CH3 OH selectivity at high temperature.However,the other structure of In2O_(3) with rhombohedral corundum-type(denoted as rh-In2O_(3))rarely been investigated as catalyst.Herein,c-In2O_(3) and rh-In2O_(3) were prepared and comparatively studied for CO_(2) hydrogenation.The results indicated that c-In2O_(3) showed higher CO_(2) conversion activity than rh-In2O_(3) due to the impressive reducibility and reactivity.Whereas rh-In2O_(3) had higher CH3 OH selectivity due to weaker CH3 OH and stronger CO adsorption on rhIn2O_(3).Although c-In2O_(3) and rh-In2O_(3) catalysts showed different CO_(2) hydrogenation perfo rmance,in-situ diffuse reflectance infrared Fourier transform spectroscopy showed CO_(2) can be reduced to CO through redox cycling and hydrogenation to CH3 OH through formate path.
文摘The hydrogenation of CO_(2) into methanol has attracted much attention and In_(2)O_(3) is a promising catalyst.Introducing metal elements into In_(2)O_(3)(M/In_(2)O_(3))is one of the main strategies to improve its performance.However,its mechanism and active sites remain unclear and need to be further elucidated.Here,the noble‐metal‐free In_(x)‐Co_(y) oxides catalysts were prepared.Much‐improved performance and obvious product selectivity shift were observed.The optimized catalyst(In_(1)‐Co_(4))(9.7 mmol g_(cat)^(–1) h^(–1))showed five times methanol yields than pure In_(2)O_(3)(2.2 mmol g_(cat)^(–1) h^(–1))(P=4.0 MPa,T=300°C,GHSV=24000 cm^(3)_(STP) g_(cat)^(–1) h^(–1),H_(2):CO_(2)=3).And the cobalt‐catalyzed CO_(2) methanation activity was suppressed,although cobalt was most of the metal element.To unravel this selectivity shift,detailed catalysts performance evaluation,together with several in‐situ and ex‐situ characterizations,were employed on cobalt and In‐Co for comparative study.The results indicated CO_(2) hydrogenation on cobalt and In‐Co catalyst both followed the formate pathway,and In‐Co reconstructed and generated a surface In_(2)O_(3)‐enriched core‐shell‐like structure under a reductive atmosphere.The enriched In_(2)O_(3) at the surface significantly enhanced CO_(2) adsorption capacity and well stabilized the intermediates of CO_(2) hydrogenation.CO_(2) and carbon‐containing intermediates adsorbed much stronger on In‐Co than cobalt led to a feasible surface C/H ratio,thus allowing the*CH_(3)O to desorb to produce CH_(3)OH instead of being over‐hydrogenated to CH_(4).
基金National Natural Science Foundation of China (Grant No. 51773092)National Natural Science Foundation of China (21825202, 21575135, 21733012, 21633008, 21605136)+3 种基金Research Fundation of State Key Lab (ZK201717)the support from Department of Education of Jilin Province (JJKH20190767KJ)Department of Education of Guangdong Province (2017KCXTD031)Science Foundation for High-level Talents of Wuyi University (2017RC23)
文摘Electrocatalytic CO2 reduction (ECR) into value-added chemicals offers potential solution for renewable energy as well as global carbon footprint concerns. In this review we introduce the general methods and metrics that are commonly applied in ECR, followed by a discussion of current reaction mechanisms and different pathways. We highlight how size and structure of electrocatalysts affect ECR performance and review recent advances in metalfree and single-atom catalysts. The challenges of ECR are also discussed and optimistic perspectives are made for future work.
基金supported by the National Foundation of China (Grant No. 91545129, 21575135 and 21605136)the "Strategic Priority Research Program" of the CAS (Grant No. XDA09010401)+1 种基金the National Key R&D Program of China (Grant No. 2016YBF0100100)the Science and Technology Development Program of the Jilin Province (Grant No. 20150623002TC and 20160414034GH)
文摘In the past decade, the aprotic lithium-oxygen(Li-O_2) battery has generated a great deal of interest because theoretically it can store more energy than today's lithium-ion batteries. Although considerable research efforts have been devoted to the R&D of this potentially disruptive technology, many scientific and engineering obstacles still remain to be addressed before a practical device could be realized. In this review, we summarize recent advances in the fundamental understanding of the O_2 electrochemistry in Li-O_2 batteries, including the O_2 reduction to Li_2O_2 on discharge and the reverse Li_2 O_2 oxidation on recharge and factors that exert strong influences on the redox of O_2/Li_2O_2. In addition,challenges and perspectives are also provided for the future study of Li—O_2 batteries.
基金the financial support from the National Natural Science Foundation of China(No. 21675106)the 111 Project(No. B14041)+2 种基金Natural Science Basic Research Plan in Shaanxi Province of China (No. 2017JM2019)the Program for Changjiang Scholars and Innovative Research Team in University (No. 14R33)the Program for Innovative Research Team in Shaanxi Province(No. 2014KCT-28)
文摘Herein, we reported a new label-free and fluorescence turn-on biosensor based on cationic conjugated poly（9,9-bis（6＇-N,N,N-trimethylammonium）hexyl）fluorine phenylene）（PFP） and perylene diimide derivatives（PDI）. Cationic PFP, single-stranded nucleic acid and PDI were used as signal reporter, probe and fluorescence quencher, respectively. In the presence of nucleic acids, they form complexes with PFP and PDI through strong electrostatic attraction interactions, resulting in PDI aggregating on nucleic acids and fluorescence of PFP being quenched. When nucleic acids are hydrolyzed by enzymes or their conformation is changed via recognizing targets, the effective aggregation of PDI is disrupted and the quenching ability is decreased. Thus the fluorescence of PFP recovers significantly. By taking advantage of the mechanism, we construct a new biosensor for endonuclease and small molecules detection. Here, S1 nuclease and bisphenol A are used as model systems. The detection limit of the SI nuclease and BPA are1.0×10^-6U/mL and 0.05 ng/mL, respectively. Our method is sensitive, cost-effective and simple, and provides a new platform for bioanalysis.
基金support from the High Level Scientific Research Cultivation Project of Huanggang Normal University(202108504)from the National Natural Science Foundation of China(31571832)。
文摘Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related diseases.Targeted AGE inhibition includes scavengers of reactive carbonyl species(RCS)such as methylglyoxal(MG),glyoxalase-1 enhancers,Nrf2/ARE pathway activators,AGE/RAGE formation inhibitors and other antiglycatng agents.Citrus flavonoids have demonstrated antioxidant and anti-inflammatory effects and are also found to be effective antiglycating agents.Herein,we reviewed the up to date progress of the antiglycation effects of citrus flavonoids and associated mechanisms.Major citrus flavonoids,hesperedin and its aglycone,hesperetin,inhibited glycation by scavenging MG forming mono-or di-flavonoid adducts with MG,enhanced the activity of glyoxase-1,activated Akt/Nrf2 signal pathway while inhibiting AGE/RAGE/NF-κB pathway,reduced the formation of Nε-(carboxylmethyl)lysine(CML)and pentosidine,inhibited aldol reductase activity and decreased the levels of fructosamine.The antiglycating activity and mechanisms of other flavonoids was also summarized in this review.In conclusion,citrus flavonoids possess effective antiglycating activity via different mechanisms,yet there are many challenging questions remaining to be studied in the near future such as in vivo testing and human study of citrus flavonoids for efficacy,effectiveness and adverse effects of citrus flavonoids as a functional food in managing high levels of AGEs and controlling AGE-induced chronic diseases,diabetic complications in particular.
基金the National Natural Science Foundation of China(No.52372101,52032005)。
文摘Dielectric pulse capacitors are of great concerns due to the fast charge/discharge rate and high-power density over traditional counterparts.However,energy-storage capacitor in power converters typically works at a large DC-biased voltage,where the energy-storge density(Wdis)and efficiency(h)will dramatically decay,thus fatally blocks its further applications.Herein,we proposed a synergistic strategy to achieve a comprehensively improved energy storage property in Bi1exNaxTiO_(3)-NaNbO_(3)based ceramics.Configuration of chemical composition optimization,A-site vacancy engineering,grain size refinement,and sample thickness reduction were designed in the ceramics.Finally,an optimum Wdis of 8.04 J/cm^(3)and an ultrahigh h of 85%was achieved for the 0.50(0.95Bi_(0.52)Na_(0.44)TiO_(3)-0.05SrZrO_(3))-0.50NaNbO_(3)composite under a breakdown strength of 630 kV/cm,along with a stable DC-biased capacitance retention.Additionally,a superior performance stability was affirmed in a wide temperature/frequency range(25-150℃and 1-100 Hz,respectively).It also exhibits an impressive ability in fatigue resistance after being subjected to up to 106 cycles,which enable it to be a suitable candidate for high energy density storage devices.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(Nos.51871133 and 51671115)Department of Education of Jilin Province(No.JJKH20190767KJ)Department of Science and Technology of Shandong Province for Young Tip-top Talent Support Project.
文摘Among various efficient electrocatalysts for water splitting,CoFe and NiFe-based oxides/hydroxides are typically promising candidates thanks to their extraordinary activities towards oxygen evolution reaction (OER).However,the endeavor to advance their performance towards overall water splitting has been largely impeded by the limited activities for hydrogen evolution reaction (HER).Herein,we present a CoFeNi ternary metal-based oxide (CoFeNi-O) with impressive hierarchical bimodal channel nanostructures,which was synthesized via a facile one-step dealloying strategy.The oxide shows superior catalytic activities towards both HER and OER in alkaline solution due to the alloying effect and the intrinsic hierarchical porous structure.CoFeNi-O loaded on glass carbon electrodes only requires the overpotentials as low as 230 and 278 mV to achieve the OER current densities of 10 and 100 mA·cm-2,respectively.In particular,extremely low overpotentials of 200 and 57.9 mV are sufficient enough for Ni foam-supported CoFeNi-O to drive the current density of 10 mA·cm-2 towards OER and HER respectively,which is comparable with or even better than the already-developed state-of-the-art non-noble metal oxide based catalysts.Benefiting from the bifunctionalities of CoFeNi-O,an alkaline electrolyzer constructed by the Ni foam-supported CoFeNi-O electrodes as both the anode and the cathode can deliver a current density of 10 mA·cm-2 at a fairly low cell-voltage of 1.558 V.In view of its electrocatalytic merits together with the facile and cost-effective dealloying route,CoFeNi-O is envisioned as a promising catalyst for future production of sustainable energy resources.
文摘This paper addresses the problem of multi-objective coalition formation for task allocation. In disaster rescue, due to the dynamics of environments, heterogeneity and complexity of tasks as well as limited available agents, it is hard for the single-objective and single （task）-to-single （agent） task allocation approaches to handle task allocation in such circumstances. To this end, two multi-objective coalition formation for task allocation models are proposed for disaster rescues in this paper. First, through coalition formation, the proposed models enable agents to cooperatively perform complex tasks that cannot be completed by single agent. In addition, through adjusting the weights of multiple task allocation objectives, the proposed models can employ the linear programming to generate more adaptive task allocation plans, which can satisfy different task allocation requirements in disaster rescue. Finally, through employing the multi-stage task allocation mechanism of the dynamic programming, the proposed models can handle the dynamics of tasks and agents in disaster environments. Experimental results indicate that the proposed models have good performance on coalition formation for task allocation in disaster environments, which can generate suitable task allocation plans according to various objectives of task allocation.
基金supported by the National Postdoctoral Program for Innovative Talents(Grant No.BX20190158)National Natural Science Foundation of China(Grant Nos.52032005 and 51672148)the Shuimu Tsinghua Scholar.
文摘It is a very difficult work to sinter K_(0.5)Na_(0.5)NbO_(3)(KNN)-based materials with good reduction resistance in strong reducing atmosphere.0.945K_(0.48)Na_(0.52)Nb_(0.96)Ta_(0.04)O_(3)-0.055BaZrO_(3)+0.03ZrO_(2)+y mol%MnO(KNNT-0.055BZ+0.03Zr+yMn)ceramics sintered in reducing atmosphere were prepared successfully by conventional solid-state reaction methods.MnO dopant increases grain size at y=5-8 due to strong lattice distortion and then decreases grain size at y=9 due to much Mn4Nb2O9 accumulated at the grain boundary.MnO dopant as an excellent sintering aid can effectively reduce volatilization of alkali metal by decreasing the sintering temperature(T_(sinter)).Reducing alkali metal volatilization can greatly reduce oxygen vacancies and improve piezoelectric properties.MnO dopant can improve the anti-reduction properties.The KNNT-0.055BZ+0.03Zr+yMn ceramics aty=6-9 show outstanding anti-fatigue of unipolar piezoelectric strain under the synergistic effect of reduced oxygen vacancies due to reduced volatilization and increased grain size.Piezoelectric properties and temperature stability of KNNT-0.055BZ+0.03Zr ceramics sintered in reducing atmosphere are improved simultaneously by MnO dopant.Optimum inverse piezoelectric coefficient(d33)of ceramics at y=8 reaches up to 480 pm/V under low driving electric field E=20 kV/cm at room temperature,and its temperature stability of d33 reaches 158℃.It will be an excellent lead-free material candidate for the preparation of multilayer piezoelectric actuators co-fired with nickel electrode.
基金supported by the Beijing Natural Science Foundation under Nos.4192004 and 4212016the National Natural Science Foundation of China under Grant Nos.61703013 and 62072016+3 种基金the Project of Beijing Municipal Education Commission under Grant Nos.KM201810005024 and KM201810005023Foundation from School of Computer Science and Technology,Beijing University of Technology under Grants No.2020JSJKY005the International Research Cooperation Seed Fund of Beijing University of Technology under Grant No.2021B29National Engineering Laboratory for Industrial Big-data Application Technology.
文摘Traffic flow prediction plays an important role in intelligent transportation applications,such as traffic control,navigation,path planning,etc.,which are closely related to people's daily life.In the last twenty years,many traffic flow prediction approaches have been proposed.However,some of these approaches use the regression based mechanisms,which cannot achieve accurate short-term traffic flow predication.While,other approaches use the neural network based mechanisms,which cannot work well with limited amount of training data.To this end,a light weight tensor-based traffic flow prediction approach is proposed,which can achieve efficient and accurate short-term traffic flow prediction with continuous traffic flow data in a limited period of time.In the proposed approach,first,a tensor-based traffic flow model is proposed to establish the multi-dimensional relationships for traffic flow values in continuous time intervals.Then,a CANDECOMP/PARAFAC decomposition based algorithm is employed to complete the missing values in the constructed tensor.Finally,the completed tensor can be directly used to achieve efficient and accurate traffic flow prediction.The experiments on the real dataset indicate that the proposed approach outperforms many current approaches on traffic flow prediction with limited amount of traffic flow data.
基金supported by the National Natural Science Foundation of China (91545129, 21575135, 21605136)the “Strategic Priority Research Program” of the Chinese Academy of Science (XDA09010401)+1 种基金the National Key Technology Research and Development Program of China (2016YBF0100100)the Science and Technology Development Program of the Jilin Province (20150623002TC, 20160414034GH)
文摘When aprotic Li-O2 batteries recharge, the solid Li2O2 in the positive electrode is oxidized, which often exhibits a continuous or step increase in the charging potential as a function of the charging capacity, and its origin remains incompletely understood. Here, we report a model study of electro-oxidation of a Li2O2 film on an Au electrode using voltammetry coupled with in situ Raman spectroscopy. It was found that the charging reaction initializes at the positive electrodelLizO2 interface, instead of the previously presumed Li2O2 surface, and consists of two temporally and spatially separated Li2O2 oxidation processes, accounting for the potential rise during charging of Li-O2 batteries. Moreover, the electrode surface-initialized oxidation can disintegrate the Li2O2 film resulting in a loss of Li2O2 into electrolyte solution, which drastically decreases the charging efficiency and highlights the importance of using soluble electro-catalyst for the complete charging of Li-02 batteries.
