We consider a tachyonic scalar field as a model of dark energy with interac- tion between components in the case of variable G and A. We assume a fiat Universe with a specific form of scale factor and study cosmologic...We consider a tachyonic scalar field as a model of dark energy with interac- tion between components in the case of variable G and A. We assume a fiat Universe with a specific form of scale factor and study cosmological parameters numerically and graphically. Statefinder analysis is also performed. For a particular choice of in- teraction parameters we succeed in obtaining an analytical expression of densities. We find that our model will be stable at the late stage but there is an instability in the early Universe, so we propose this model as a realistic model of our Universe.展开更多
Sodium-ion capacitors(SICs)have great potential in energy storage due to their low cost,the abundance of Na,and the potential to deliver high energy and power simultaneously.This article demonstrates a template-assist...Sodium-ion capacitors(SICs)have great potential in energy storage due to their low cost,the abundance of Na,and the potential to deliver high energy and power simultaneously.This article demonstrates a template-assisted method to induce graphitic nanodomains and micro-mesopores into nitrogen-doped carbons.This study elucidates that these graphitic nanodomains are beneficial for Na+storage.The obtained N-doped carbon(As8Mg)electrode achieved a reversible capacity of 254 mA h g^(-1)at 0.1 A g^(-1).Moreover,the As8Mg-based SIC device achieves high combinations of power/energy densities(53 W kg^(-1)at 224 Wh kg^(-1)and 10410 W kg^(-1)at 51 Wh kg^(-1))with outstanding cycle stability(99.7%retention over 600 cycles at 0.2 A g^(-1)).Our findings provide insights into optimizing carbon’s microstructure to boost sodium storage in the pseudocapacitive mode.展开更多
Nowadays,iron ions as a ubiquitous heavy metal pollutant are gradually concerned and the convenient and quick removal of excessive iron ions in groundwater has become a major challenge for the safety of drinking water...Nowadays,iron ions as a ubiquitous heavy metal pollutant are gradually concerned and the convenient and quick removal of excessive iron ions in groundwater has become a major challenge for the safety of drinking water.In this study,boron-doped biochar(B-BC)was successfully prepared at various preparation conditions with the addition of boric acid.The as-prepared material has a more developed pore structure and a larger specific surface area(up to 897.97 m2/g).A series of characterization results shows that boric acid effectively activates biochar,and boron atoms are successfully doped on biochar.Compared with the ratio of raw materials,the pyrolysis temperature has a greater influence on the amount of boron doping.Based on Langmuir model,the maximum adsorption capacity of 800 B-BC1:2 at25℃,40℃,55℃ are 50.02 mg/g,95.09 mg/g,132.78 mg/g,respectively.Pseudo-second-order kinetic model can better describe the adsorption process,the adsorption process is mainly chemical adsorption.Chemical complexation,ions exchange,and co-precipitation may be the main mechanisms for Fe2+removal.展开更多
D-Glycero-D-mannno-heptose 1β,7-bisphosphate(HBPβ)is an important intermediate for constructing the core structure of Gram-negative bacterial lipopolysaccharides and was reported as a pathogen-associated molecular p...D-Glycero-D-mannno-heptose 1β,7-bisphosphate(HBPβ)is an important intermediate for constructing the core structure of Gram-negative bacterial lipopolysaccharides and was reported as a pathogen-associated molecular pattern(PAMP)that regulates immune responses.HBPβwith 3-O-amyl amine linker and its monophosphate derivative D-glycero-D-mannno-heptose 7-phosphate(HP)with 1α-amyl amine linker have been synthesized as candidates for immunity study of HBPβ.The O3-amyl amine linker of heptose was installed by dibutyltin oxide-mediated regioselective alkylation under fine-tuned protecting condition.The stereoselective installation of 1β-phosphate ester was achieved by NIS-mediated phosphorylation at low temperature.The strategy for installation of 3-O-amyl amine linker onto HBP derivative can be expanded to the syntheses of other conjugation-ready carbohydrates bearing anomeric phosphoester.展开更多
"C2N"-species have emerged as a promising material with carbon-like applications in sorption,gas separation and energy storage,while with much higher polarity and functionality.Controlled synthesis of"C..."C2N"-species have emerged as a promising material with carbon-like applications in sorption,gas separation and energy storage,while with much higher polarity and functionality.Controlled synthesis of"C2N"structure is still based on complex and less-sustainable monomers,which prohibits its broader industrial application.Here we report a class of well-defined C2(NxOySz)1 carbons with both high content of N/O/S heteroatoms and large specific surface area of up to 1704 m^2 g^-1,which can be efficiently synthesized through a simple additive condensation process using simple gallic acid and thiourea as the building blocks,without subtractive activation.This 1,4-para tri-doped C2(NxOySz)1 structure leads to sufficient CO2 adsorption capacity(3.0 mmol g^-1 at 273 K,1 bar)and a high CO2/N2 selectivity(47.5 for a 0.15/0.85 CO2/N2 mixture at 273 K).Related to the polarity,the polar frameworks can be used as supercapacitor electrodes,with record specific capacitances as high as 255 F g^-1 at 3.5 V for a symmetric supercapacitor in ionic liquid electrolyte.This work discloses a general way for preparing a novel family of multifunctional,high heteroatomdoped porous materials for various applications.展开更多
Helicobacter pylori(H.pylori)infection is a threat to human health.The lipopolysaccharide(LPS)O-antigen holds promise for developing vaccines.It is meaningful to explore the immunological activity of oligosaccharides ...Helicobacter pylori(H.pylori)infection is a threat to human health.The lipopolysaccharide(LPS)O-antigen holds promise for developing vaccines.It is meaningful to explore the immunological activity of oligosaccharides with different lengths and frameshifts for antigen development.Herein,a glycan library of H.pylori O2 O-antigen containing eight fragments is constructed.After screening with anti-H.pylori O2 LPS sera and patients’sera by glycan microarray,the disaccharide HPO2G-2b and trisaccharide HPO2G-3a show strong antigenicity and then are separately conjugated with carrier protein CRM197.Both glycoconjugates elicit a robust immunoglobulin G(IgG)immune response in rabbits.The anti-HPO2G-3a IgG antibodies possess a much stronger binding affinity with the LPS and bacteria of H.pylori O2 than the anti-HPO2G-2b IgG antibodies.There is no cross-reaction between both sera IgG antibodies with LPS and bacteria of H.pylori O1,O6,and E.coli.The results demonstrate the trisaccharide HPO2G-3a is a promising candidate for H.pylori vaccine development.展开更多
In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in...In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in the ethanol oxidation reaction(EOR)for clean hydrogen production.Both,the metal phase and the carbon support play critical roles in the electrocatalysts final performance.Lower NPs size distribution was obtained over supports with low atomic C/N ratios(i.e.,4 and 6)and defined porosity(i.e.,1701 m^(2)g^(-1)for Pt Ru/CNZ and 1834 m^(2)g^(-1)for Pt Ru/CLZ,respectively).In contrast,a lower C/N ratio and poor porous network(i.e.,65 m^(2)g^(-1),Pt Ru/CLK)led to the largest particle size and fostered an increase of the alloying degree between Pt and Ru NPs(i.e.,3%for C/N~6 and 28%for C/N~3).Electrochemical active surface area was found to increase with decreasing NPs size and the alloy extent,due to a higher availability of Pt active sites.Accelerated degradation tests showed that Pt Ru/NCs outperform similar to Pt Ru NPs on commercial carbon pointing at the stabilizing effect of NCs.Pt Ru/CNZ exhibited the best electrochemical performance(i.e.,69.1 m A mgPt-1),outperforming Pt Ru/CLZ and Pt Ru/CLK by3-and 9-fold,respectively,due to a suitable compromise between particle sizes,degree of alloy,textural properties and elemental composition.Best anodes were scaled-up to a proton exchange membrane cell and Pt Ru/CNZ was proved to provide the best electrocatalytic activity(262 m A cm^(-2)and low energy requirements),matching the values obtained by the state of the art of EOR electrocatalysts.展开更多
Electrochemical reduction from nitrate into ammonia is a chance for nitrate removal from drinking water,while at higher concentrations,this 8-electron reduction process could even become relevant for energy storage,hi...Electrochemical reduction from nitrate into ammonia is a chance for nitrate removal from drinking water,while at higher concentrations,this 8-electron reduction process could even become relevant for energy storage,high conversions and low onset potentials assumed.Herein,we report the synthesis and analysis of a NiFe_(2)O_(4)/C-MS hybrid system made by a molten-salt strategy where the Ni-Fe oxide spinel nanoparticles act as the active center for electrochemical nitrate(NO_(3)−)reduction reaction,while the microporous carbon serves as a conductive support to form a cohesive electrode material.The NiFe_(2)O_(4)/C-MS catalyst achieves a maximum NH3 yield rate of 5.4 mg mgcat.^(−1)h^(−1)and Faradaic efficiency of 98%at−0.6 V versus reversible hydrogen electrode.With NiFe_(2)O_(4)nanoparticles buried into microporous carbon,the onset potential decreases dramatically.We propose that this reduction originates from charge redistribution in NiFe_(2)O_(4)in the electronic heterojunction with carbon,while enhanced electrolyte diffusion in microporous carbon facilitates high conversion rates.Density functional theory calculations clarify the low energy barrier on NiFe_(2)O_(4),highlighting the essential role of Ni in activating Fe species.The COMSOL Multiphysics simulations demonstrate that the microporous curled carbon accelerates NO_(3)−transport and enhances adsorption on the reactive sites.This work offers insights for designing carbon-based nanocomposites for efficient nitrate reduction electrocatalysis.展开更多
Polymeric carbon nitride(CN)as a metal-free photocatalyst holds great promise to produce high-value chemicals and H_(2) fuel utilizing clean solar energy.However,the wider deployment of pristine CN is critically hampe...Polymeric carbon nitride(CN)as a metal-free photocatalyst holds great promise to produce high-value chemicals and H_(2) fuel utilizing clean solar energy.However,the wider deployment of pristine CN is critically hampered by the poor charge carrier transport and high recombination.Herein,we develop a facile salt template-assisted interfacial polymerization strategy that insitu introduces alkali ions(Na+,K+)and nitrogen defects in CN(denoted as v-CN-KNa)to simultaneously promote charge separation and transportation and steer photoexcited holes and electrons to their oxidation and reduction sites.The photocatalyst exhibits an impressive photocatalytic H_(2) evolution rate of 8641.5μmol·g^(−1)·h^(−1)(33-fold higher than pristine CN)and also works readily in real seawater(10752.0μmol·g^(−1)·h^(−1))with a high apparent quantum efficiency up to 18.5%at 420 nm.In addition,we further demonstrate that the v-CN-KNa can simultaneously produce H_(2) and N-benzylidenebenzylamine without using any other sacrificial reagent.In situ characterizations and DFT calculations reveal that the alkali ions notably promote charge transport,while the nitrogen defects generate abundant edge active sites,which further contribute to efficient electron excitation to trigger photoredox reactions.展开更多
Carbon materials with controlled nanostructure or,better,covalent two-dimensional systems are currently a scientific megatrend,but not new as such.Many applications ranging from conductance,sensing,selective sorption,...Carbon materials with controlled nanostructure or,better,covalent two-dimensional systems are currently a scientific megatrend,but not new as such.Many applications ranging from conductance,sensing,selective sorption,over(electro)catalysis to stretchable electronics,energy conversion,and storage were recently presented and will constitute the core of future technology.It is also commonplace that all these applications can still be improved by the development of new carbon or carbon derived materials to be implemented at the industrial scale.The relatively recent exploration of graphene,as for instance explored also in the European Graphene Flagship,marked a turn-around in the societal perception of all of those technologies.However,delaminated graphene is not new as such,with the employed techniques by Hummers1 or H.P.Boehm^2 as early as 1958 and 1962.展开更多
Fe(hydr)oxides have a substantial impact on the structure and stability of soil organic carbon(SOC)pools and also drive organic carbon turnover processes via reduction–oxidation reactions.Currently,many studies have ...Fe(hydr)oxides have a substantial impact on the structure and stability of soil organic carbon(SOC)pools and also drive organic carbon turnover processes via reduction–oxidation reactions.Currently,many studies have paid much attention to organic matter–Fe mineral–microbial interactions on SOC turnover,while there is few research on how exogenous carbon addition abiotically regulates the intrinsic mechanisms of Fe-mediated organic carbon conversion.The study investigated the coupling process of artificial humic acid(A-HA)and Fe(hydr)oxide,the mechanism of inner-sphere ligands,and the capacity for carbon sequestration using transmission electron microscopy,thermogravimetric,x-ray photoelectron spectroscopy,and wet-chemical disposal.Furthermore,spherical aberration-corrected scanning transmission electron microscopy–electron energy loss spectroscopy and M鰏sbauer spectra have been carried out to demonstrate the spatial heterogeneity of A-HA/Fe(hydr)oxides and reveal the relationship between the increase in Fe-phase crystallinity and redox sensitivity and the accumulation of organic carbon.Additionally,the dynamics of soil structures on a microscale,distribution of carbon–iron microdomains,and the cementing-gluing effect can be observed in the constructing nonliving anthropogenic soils,confirming that the formation of stable aggregates is an effective approach to achieving organic carbon indirect protection.We propose that exogenous organic carbon inputs,specifically A-HA,could exert a substantial but hitherto unexplored effect on the geochemistry of iron–carbon turnover and sequestration in anoxic water/solid soils and sediments.展开更多
In recent years,the concept of rechargeable aqueous Zn–CO_(2) batteries has attracted extensive attention owing to their dual functionality of power supply and simultaneous conversion of CO_(2) into value-added chemi...In recent years,the concept of rechargeable aqueous Zn–CO_(2) batteries has attracted extensive attention owing to their dual functionality of power supply and simultaneous conversion of CO_(2) into value-added chemicals or fuels.The state-of-the-art research has been mainly focused on the exploration of working mechanisms and catalytic cathodes but hardly applies an integrative view.Although numerous studies have proven the feasibility of rechargeable aqueous Zn–CO_(2) batteries,challenges remain including the low CO_(2) conversion efficiency,poor battery capacity,and low energy efficiency.This review systematically summarizes the working principles and devices,and the catalytic cathodes used for Zn–CO_(2) batteries.The challenges and prospects in this field are also elaborated,providing insightful guidance for the future development of rechargeable aqueous Zn–CO_(2) batteries with high performance.展开更多
The diterpenoid paclitaxel(Taxol)is a chemotherapy medication widely used as a first-line treatment against several types of solid cancers.The supply of paclitaxel from natural sources is limited.However,missing knowl...The diterpenoid paclitaxel(Taxol)is a chemotherapy medication widely used as a first-line treatment against several types of solid cancers.The supply of paclitaxel from natural sources is limited.However,missing knowledge about the genes involved in several specific metabolic steps of paclitaxel biosynthesis has rendered it difficult to engineer the full pathway.In this study,we used a combination of transcriptomics,cell biology,metabolomics,and pathway reconstitution to identify the complete gene set required for the heterologous production of paclitaxel.We identified the missing steps from the current model of paclitaxel biosynthesis and confirmed the activity of most of the missing enzymes via heterologous expression in Nicotiana benthamiana.Notably,we identified a new C4β-C20 epoxidase that could overcome the first bottleneck of metabolic engineering.We used both previously characterized and newly identified oxomutases/epoxidases,taxane 1β-hydroxylase,taxane 9aα-hydroxylase,taxane 9α-dioxygenase,and phenylalanine-CoA ligase,to successfully biosynthesize the key intermediate baccatin Ill and to convert baccatin Ill into paclitaxel in N.benthamiana.In combination,these approaches establisha metabolic route to taxoidbiosynthesis and provide insights into the unique chemistry that plants use to generate complex bioactive metabolites.展开更多
In the neural system,a large number of neurons con-tinuously produce and transmit electrophysiological sig-nals,which communicate between neurons and brain regions.Naturally,bioinformation transformation de-pends on c...In the neural system,a large number of neurons con-tinuously produce and transmit electrophysiological sig-nals,which communicate between neurons and brain regions.Naturally,bioinformation transformation de-pends on conversion from ionics to electronics,and electronics-based neural recording technologies(Fig.1)have been extensively developed since the primitive vol-tage clamp in 1949[1].展开更多
Carbon emission from soil is not only one of the major sources of greenhouse gases but also threatens biological diversity,agricultural productivity,and food security.Regulation and control of the soil carbon pool are...Carbon emission from soil is not only one of the major sources of greenhouse gases but also threatens biological diversity,agricultural productivity,and food security.Regulation and control of the soil carbon pool are political practices in many countries around the globe.Carbon pool management in engineering sense is much bigger and beyond laws and monitoring,as it has to contain proactive elements to restore active c arbon.Biogeochemistry teaches us that soil microorganisms are crucial to manage the carbon content efctivelye Adding carbon materials to soil is thereby not directly sequestration,as interaction of appropriately designed materials with the soil microbiome can result in both:metabolization and thereby nonsustainable use of the added carbon,or-more favorably-a biological amplifcation of human efforts and sequestration of extra CO,by microbial growth.We review here potential approaches to govern soil arbon,with a special focus set on the emerging practice of adding manufactured carbon materials to control soil carbon and its biological dynamiss.Notably,research on so called"biochar"is already relatively mature,while the role of artifidial humic substance(A-HS)in microbial carbon sequestration is still in the developing stage.However,it is shown that the preparation and application of A-HS are large biological levers,as they directly interact with the envir onment and community building of the biological soil system.We believe that A HS can play a central role in stabilzing carbon pools in soil.展开更多
The folding dynamics of small single-domain proteins is a current focus ofsimulations and experiments. Many of these proteins are ‘two-state folders’, i.e. pro-teins that fold rather directly from the denatured stat...The folding dynamics of small single-domain proteins is a current focus ofsimulations and experiments. Many of these proteins are ‘two-state folders’, i.e. pro-teins that fold rather directly from the denatured state to the native state, without pop-ulating metastable intermediate states. A central question is how to characterize theinstable, partially folded conformations of two-state proteins, in particular the rate-limiting transition-state conformations between the denatured and the native state.These partially folded conformations are short-lived and cannot be observed directlyin experiments. However, experimental data from detailed mutational analyses of thefolding dynamics provide indirect access to transition states. The interpretation ofthese data, in particular the reconstruction of transition-state conformations, requiressimulation and modeling. The traditional interpretation of the mutational data aimsto reconstruct the degree of structure formation of individual residues in the transitionstate, while a novel interpretation aims at degrees of structure formation of cooperativesubstructures such as α-helices and β-hairpins. By splitting up mutation-induced freeenergies into secondary and tertiary structural components, the novel interpretationresolves some of the inconsistencies of the traditional interpretation.展开更多
基金supported by EU funds in the frame of the program FP7-Marie Curie Initial Training Network INDEX NO. 289968
文摘We consider a tachyonic scalar field as a model of dark energy with interac- tion between components in the case of variable G and A. We assume a fiat Universe with a specific form of scale factor and study cosmological parameters numerically and graphically. Statefinder analysis is also performed. For a particular choice of in- teraction parameters we succeed in obtaining an analytical expression of densities. We find that our model will be stable at the late stage but there is an instability in the early Universe, so we propose this model as a realistic model of our Universe.
基金the China Scholarship Council for financial supportthe Max Planck Society for financial supportOpen Access funding enabled and organized by Projekt DEAL
文摘Sodium-ion capacitors(SICs)have great potential in energy storage due to their low cost,the abundance of Na,and the potential to deliver high energy and power simultaneously.This article demonstrates a template-assisted method to induce graphitic nanodomains and micro-mesopores into nitrogen-doped carbons.This study elucidates that these graphitic nanodomains are beneficial for Na+storage.The obtained N-doped carbon(As8Mg)electrode achieved a reversible capacity of 254 mA h g^(-1)at 0.1 A g^(-1).Moreover,the As8Mg-based SIC device achieves high combinations of power/energy densities(53 W kg^(-1)at 224 Wh kg^(-1)and 10410 W kg^(-1)at 51 Wh kg^(-1))with outstanding cycle stability(99.7%retention over 600 cycles at 0.2 A g^(-1)).Our findings provide insights into optimizing carbon’s microstructure to boost sodium storage in the pseudocapacitive mode.
基金the financial support by Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(No.Z019005)the Longjiang Scholars for young scientist。
文摘Nowadays,iron ions as a ubiquitous heavy metal pollutant are gradually concerned and the convenient and quick removal of excessive iron ions in groundwater has become a major challenge for the safety of drinking water.In this study,boron-doped biochar(B-BC)was successfully prepared at various preparation conditions with the addition of boric acid.The as-prepared material has a more developed pore structure and a larger specific surface area(up to 897.97 m2/g).A series of characterization results shows that boric acid effectively activates biochar,and boron atoms are successfully doped on biochar.Compared with the ratio of raw materials,the pyrolysis temperature has a greater influence on the amount of boron doping.Based on Langmuir model,the maximum adsorption capacity of 800 B-BC1:2 at25℃,40℃,55℃ are 50.02 mg/g,95.09 mg/g,132.78 mg/g,respectively.Pseudo-second-order kinetic model can better describe the adsorption process,the adsorption process is mainly chemical adsorption.Chemical complexation,ions exchange,and co-precipitation may be the main mechanisms for Fe2+removal.
基金supported by the National Natural Science Foundation of China(Nos.21877052 and 21907039)the Natural Science Foundation of Jiangsu Province(Nos.BK20180030and BK20190575)+5 种基金the High-end Foreign Experts Recruitment ProgramNational First-class Discipline Program of Light Industry Technology and Engineering(No.LITE2018-14)the 111 Project(No.111-2-06)the Max Planck Society International Partner Group ProgramChina Scholarship Council(CSC)the Max-Planck Society for generous financial support。
文摘D-Glycero-D-mannno-heptose 1β,7-bisphosphate(HBPβ)is an important intermediate for constructing the core structure of Gram-negative bacterial lipopolysaccharides and was reported as a pathogen-associated molecular pattern(PAMP)that regulates immune responses.HBPβwith 3-O-amyl amine linker and its monophosphate derivative D-glycero-D-mannno-heptose 7-phosphate(HP)with 1α-amyl amine linker have been synthesized as candidates for immunity study of HBPβ.The O3-amyl amine linker of heptose was installed by dibutyltin oxide-mediated regioselective alkylation under fine-tuned protecting condition.The stereoselective installation of 1β-phosphate ester was achieved by NIS-mediated phosphorylation at low temperature.The strategy for installation of 3-O-amyl amine linker onto HBP derivative can be expanded to the syntheses of other conjugation-ready carbohydrates bearing anomeric phosphoester.
基金support provided by Zhengzhou University and the National Natural Science Foundation of China(51873198).
文摘"C2N"-species have emerged as a promising material with carbon-like applications in sorption,gas separation and energy storage,while with much higher polarity and functionality.Controlled synthesis of"C2N"structure is still based on complex and less-sustainable monomers,which prohibits its broader industrial application.Here we report a class of well-defined C2(NxOySz)1 carbons with both high content of N/O/S heteroatoms and large specific surface area of up to 1704 m^2 g^-1,which can be efficiently synthesized through a simple additive condensation process using simple gallic acid and thiourea as the building blocks,without subtractive activation.This 1,4-para tri-doped C2(NxOySz)1 structure leads to sufficient CO2 adsorption capacity(3.0 mmol g^-1 at 273 K,1 bar)and a high CO2/N2 selectivity(47.5 for a 0.15/0.85 CO2/N2 mixture at 273 K).Related to the polarity,the polar frameworks can be used as supercapacitor electrodes,with record specific capacitances as high as 255 F g^-1 at 3.5 V for a symmetric supercapacitor in ionic liquid electrolyte.This work discloses a general way for preparing a novel family of multifunctional,high heteroatomdoped porous materials for various applications.
基金financial support from the National Natural Science Foundation of China(22177041,22277042,22077052,22107037,22207042)the China Postdoctoral Science Foundation(2021M691279)+1 种基金the 111 Project(111-2-06)the Max Planck Society International Partner Group Program,and the China Scholarship Council(CSC)for funding.P.H.S.thanks the Max Plank Society forgenerous financial support.
文摘Helicobacter pylori(H.pylori)infection is a threat to human health.The lipopolysaccharide(LPS)O-antigen holds promise for developing vaccines.It is meaningful to explore the immunological activity of oligosaccharides with different lengths and frameshifts for antigen development.Herein,a glycan library of H.pylori O2 O-antigen containing eight fragments is constructed.After screening with anti-H.pylori O2 LPS sera and patients’sera by glycan microarray,the disaccharide HPO2G-2b and trisaccharide HPO2G-3a show strong antigenicity and then are separately conjugated with carrier protein CRM197.Both glycoconjugates elicit a robust immunoglobulin G(IgG)immune response in rabbits.The anti-HPO2G-3a IgG antibodies possess a much stronger binding affinity with the LPS and bacteria of H.pylori O2 than the anti-HPO2G-2b IgG antibodies.There is no cross-reaction between both sera IgG antibodies with LPS and bacteria of H.pylori O1,O6,and E.coli.The results demonstrate the trisaccharide HPO2G-3a is a promising candidate for H.pylori vaccine development.
基金the Spanish Ministry of Science and Innovation(State Research Agency.Project PID2019-107499RB100)for the financial supportThe Max Planck Society。
文摘In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in the ethanol oxidation reaction(EOR)for clean hydrogen production.Both,the metal phase and the carbon support play critical roles in the electrocatalysts final performance.Lower NPs size distribution was obtained over supports with low atomic C/N ratios(i.e.,4 and 6)and defined porosity(i.e.,1701 m^(2)g^(-1)for Pt Ru/CNZ and 1834 m^(2)g^(-1)for Pt Ru/CLZ,respectively).In contrast,a lower C/N ratio and poor porous network(i.e.,65 m^(2)g^(-1),Pt Ru/CLK)led to the largest particle size and fostered an increase of the alloying degree between Pt and Ru NPs(i.e.,3%for C/N~6 and 28%for C/N~3).Electrochemical active surface area was found to increase with decreasing NPs size and the alloy extent,due to a higher availability of Pt active sites.Accelerated degradation tests showed that Pt Ru/NCs outperform similar to Pt Ru NPs on commercial carbon pointing at the stabilizing effect of NCs.Pt Ru/CNZ exhibited the best electrochemical performance(i.e.,69.1 m A mgPt-1),outperforming Pt Ru/CLZ and Pt Ru/CLK by3-and 9-fold,respectively,due to a suitable compromise between particle sizes,degree of alloy,textural properties and elemental composition.Best anodes were scaled-up to a proton exchange membrane cell and Pt Ru/CNZ was proved to provide the best electrocatalytic activity(262 m A cm^(-2)and low energy requirements),matching the values obtained by the state of the art of EOR electrocatalysts.
基金supported by the National Natural Science Foundation of China(52373205 and 52003251)Henan Center for Outstanding Overseas Scientists(GZS_(2)022014)。
文摘Electrochemical reduction from nitrate into ammonia is a chance for nitrate removal from drinking water,while at higher concentrations,this 8-electron reduction process could even become relevant for energy storage,high conversions and low onset potentials assumed.Herein,we report the synthesis and analysis of a NiFe_(2)O_(4)/C-MS hybrid system made by a molten-salt strategy where the Ni-Fe oxide spinel nanoparticles act as the active center for electrochemical nitrate(NO_(3)−)reduction reaction,while the microporous carbon serves as a conductive support to form a cohesive electrode material.The NiFe_(2)O_(4)/C-MS catalyst achieves a maximum NH3 yield rate of 5.4 mg mgcat.^(−1)h^(−1)and Faradaic efficiency of 98%at−0.6 V versus reversible hydrogen electrode.With NiFe_(2)O_(4)nanoparticles buried into microporous carbon,the onset potential decreases dramatically.We propose that this reduction originates from charge redistribution in NiFe_(2)O_(4)in the electronic heterojunction with carbon,while enhanced electrolyte diffusion in microporous carbon facilitates high conversion rates.Density functional theory calculations clarify the low energy barrier on NiFe_(2)O_(4),highlighting the essential role of Ni in activating Fe species.The COMSOL Multiphysics simulations demonstrate that the microporous curled carbon accelerates NO_(3)−transport and enhances adsorption on the reactive sites.This work offers insights for designing carbon-based nanocomposites for efficient nitrate reduction electrocatalysis.
基金supported by the National Key Research and Development Program of the MOST(Nos.2021YFA1500400 and 2018YFA0208603)the National Natural Science Foundation of China(NSFC,Nos.21571167,51502282,22075266,and 21890751)the Fundamental Research Funds for the Central Universities(Nos.WK2060190053 and WK2060190100).
文摘Polymeric carbon nitride(CN)as a metal-free photocatalyst holds great promise to produce high-value chemicals and H_(2) fuel utilizing clean solar energy.However,the wider deployment of pristine CN is critically hampered by the poor charge carrier transport and high recombination.Herein,we develop a facile salt template-assisted interfacial polymerization strategy that insitu introduces alkali ions(Na+,K+)and nitrogen defects in CN(denoted as v-CN-KNa)to simultaneously promote charge separation and transportation and steer photoexcited holes and electrons to their oxidation and reduction sites.The photocatalyst exhibits an impressive photocatalytic H_(2) evolution rate of 8641.5μmol·g^(−1)·h^(−1)(33-fold higher than pristine CN)and also works readily in real seawater(10752.0μmol·g^(−1)·h^(−1))with a high apparent quantum efficiency up to 18.5%at 420 nm.In addition,we further demonstrate that the v-CN-KNa can simultaneously produce H_(2) and N-benzylidenebenzylamine without using any other sacrificial reagent.In situ characterizations and DFT calculations reveal that the alkali ions notably promote charge transport,while the nitrogen defects generate abundant edge active sites,which further contribute to efficient electron excitation to trigger photoredox reactions.
文摘Carbon materials with controlled nanostructure or,better,covalent two-dimensional systems are currently a scientific megatrend,but not new as such.Many applications ranging from conductance,sensing,selective sorption,over(electro)catalysis to stretchable electronics,energy conversion,and storage were recently presented and will constitute the core of future technology.It is also commonplace that all these applications can still be improved by the development of new carbon or carbon derived materials to be implemented at the industrial scale.The relatively recent exploration of graphene,as for instance explored also in the European Graphene Flagship,marked a turn-around in the societal perception of all of those technologies.However,delaminated graphene is not new as such,with the employed techniques by Hummers1 or H.P.Boehm^2 as early as 1958 and 1962.
基金supported by the Outstanding Youth Project of Heilongjiang Province(JQ2021D001)the National Natural Science Foundation of China(52279034)the National Key Research and Development Program of China(2022YFD1500100).
文摘Fe(hydr)oxides have a substantial impact on the structure and stability of soil organic carbon(SOC)pools and also drive organic carbon turnover processes via reduction–oxidation reactions.Currently,many studies have paid much attention to organic matter–Fe mineral–microbial interactions on SOC turnover,while there is few research on how exogenous carbon addition abiotically regulates the intrinsic mechanisms of Fe-mediated organic carbon conversion.The study investigated the coupling process of artificial humic acid(A-HA)and Fe(hydr)oxide,the mechanism of inner-sphere ligands,and the capacity for carbon sequestration using transmission electron microscopy,thermogravimetric,x-ray photoelectron spectroscopy,and wet-chemical disposal.Furthermore,spherical aberration-corrected scanning transmission electron microscopy–electron energy loss spectroscopy and M鰏sbauer spectra have been carried out to demonstrate the spatial heterogeneity of A-HA/Fe(hydr)oxides and reveal the relationship between the increase in Fe-phase crystallinity and redox sensitivity and the accumulation of organic carbon.Additionally,the dynamics of soil structures on a microscale,distribution of carbon–iron microdomains,and the cementing-gluing effect can be observed in the constructing nonliving anthropogenic soils,confirming that the formation of stable aggregates is an effective approach to achieving organic carbon indirect protection.We propose that exogenous organic carbon inputs,specifically A-HA,could exert a substantial but hitherto unexplored effect on the geochemistry of iron–carbon turnover and sequestration in anoxic water/solid soils and sediments.
基金This work was supported by the National Natural Science Foundation of China(No.22109044,52373205,52003251,52102166)Natural Science Foundation of Shanghai,China(No.22ZR1418500)start-up funds from the East China University of Science and Technology,and Henan Center for Outstanding Overseas Scientists(GZS2022014).
文摘In recent years,the concept of rechargeable aqueous Zn–CO_(2) batteries has attracted extensive attention owing to their dual functionality of power supply and simultaneous conversion of CO_(2) into value-added chemicals or fuels.The state-of-the-art research has been mainly focused on the exploration of working mechanisms and catalytic cathodes but hardly applies an integrative view.Although numerous studies have proven the feasibility of rechargeable aqueous Zn–CO_(2) batteries,challenges remain including the low CO_(2) conversion efficiency,poor battery capacity,and low energy efficiency.This review systematically summarizes the working principles and devices,and the catalytic cathodes used for Zn–CO_(2) batteries.The challenges and prospects in this field are also elaborated,providing insightful guidance for the future development of rechargeable aqueous Zn–CO_(2) batteries with high performance.
基金the Max Planck Society(Y.Z-.,S.A.,L.P.d.S.,F.S.,and A.R.F.),and Y.Z.,S.A.,and A.R.F.acknowledge the European Union's Horizon 2020 research and innovation programme,project PlantaSYST(SGA-CSA No.739582 under FPA No.664620)the BG05M2OP001-1.003-001-C01 project,financed by the European Regional Development Fund through the Bulgarian"Science and Education for Smart Growth"Operational Programme.J.J.M.thanks the Fonds der Chemischen Industrie,FCI for funding,H.F.thanks the Chinese Scholarship Councilfor funding.
文摘The diterpenoid paclitaxel(Taxol)is a chemotherapy medication widely used as a first-line treatment against several types of solid cancers.The supply of paclitaxel from natural sources is limited.However,missing knowledge about the genes involved in several specific metabolic steps of paclitaxel biosynthesis has rendered it difficult to engineer the full pathway.In this study,we used a combination of transcriptomics,cell biology,metabolomics,and pathway reconstitution to identify the complete gene set required for the heterologous production of paclitaxel.We identified the missing steps from the current model of paclitaxel biosynthesis and confirmed the activity of most of the missing enzymes via heterologous expression in Nicotiana benthamiana.Notably,we identified a new C4β-C20 epoxidase that could overcome the first bottleneck of metabolic engineering.We used both previously characterized and newly identified oxomutases/epoxidases,taxane 1β-hydroxylase,taxane 9aα-hydroxylase,taxane 9α-dioxygenase,and phenylalanine-CoA ligase,to successfully biosynthesize the key intermediate baccatin Ill and to convert baccatin Ill into paclitaxel in N.benthamiana.In combination,these approaches establisha metabolic route to taxoidbiosynthesis and provide insights into the unique chemistry that plants use to generate complex bioactive metabolites.
基金supported by the National Key R&D program of China (2016YFA0200803)the National Natural Science Foundation (51973227 and 51603211)
文摘In the neural system,a large number of neurons con-tinuously produce and transmit electrophysiological sig-nals,which communicate between neurons and brain regions.Naturally,bioinformation transformation de-pends on conversion from ionics to electronics,and electronics-based neural recording technologies(Fig.1)have been extensively developed since the primitive vol-tage clamp in 1949[1].
基金funding from Outstanding Youth Project of Heilongjiang Province(JQ2021D001)the Central Government for the support in the Reform and Development of Local Colleges and Universities of China(Outstanding Young Talents_Project)(2020YQ14)and Young Longjiang Scholar and Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Grant No.Z019005.
文摘Carbon emission from soil is not only one of the major sources of greenhouse gases but also threatens biological diversity,agricultural productivity,and food security.Regulation and control of the soil carbon pool are political practices in many countries around the globe.Carbon pool management in engineering sense is much bigger and beyond laws and monitoring,as it has to contain proactive elements to restore active c arbon.Biogeochemistry teaches us that soil microorganisms are crucial to manage the carbon content efctivelye Adding carbon materials to soil is thereby not directly sequestration,as interaction of appropriately designed materials with the soil microbiome can result in both:metabolization and thereby nonsustainable use of the added carbon,or-more favorably-a biological amplifcation of human efforts and sequestration of extra CO,by microbial growth.We review here potential approaches to govern soil arbon,with a special focus set on the emerging practice of adding manufactured carbon materials to control soil carbon and its biological dynamiss.Notably,research on so called"biochar"is already relatively mature,while the role of artifidial humic substance(A-HS)in microbial carbon sequestration is still in the developing stage.However,it is shown that the preparation and application of A-HS are large biological levers,as they directly interact with the envir onment and community building of the biological soil system.We believe that A HS can play a central role in stabilzing carbon pools in soil.
文摘The folding dynamics of small single-domain proteins is a current focus ofsimulations and experiments. Many of these proteins are ‘two-state folders’, i.e. pro-teins that fold rather directly from the denatured state to the native state, without pop-ulating metastable intermediate states. A central question is how to characterize theinstable, partially folded conformations of two-state proteins, in particular the rate-limiting transition-state conformations between the denatured and the native state.These partially folded conformations are short-lived and cannot be observed directlyin experiments. However, experimental data from detailed mutational analyses of thefolding dynamics provide indirect access to transition states. The interpretation ofthese data, in particular the reconstruction of transition-state conformations, requiressimulation and modeling. The traditional interpretation of the mutational data aimsto reconstruct the degree of structure formation of individual residues in the transitionstate, while a novel interpretation aims at degrees of structure formation of cooperativesubstructures such as α-helices and β-hairpins. By splitting up mutation-induced freeenergies into secondary and tertiary structural components, the novel interpretationresolves some of the inconsistencies of the traditional interpretation.
