As the need for high-energy–density batteries continues to grow, lithium-sulfur(Li–S) batteries have become a highly promising next-generation energy solution due to their low cost and exceptional energy density com...As the need for high-energy–density batteries continues to grow, lithium-sulfur(Li–S) batteries have become a highly promising next-generation energy solution due to their low cost and exceptional energy density compared to commercially available Li-ion batteries. Research into carbon-based sulfur hosts for Li–S batteries has been ongoing for over two decades, leading to a significant number of publications and patents.However, the commercialization of Li–S batteries has yet to be realized. This can be attributed, in part, to the instability of the Li metal anode. However, even when considering just the cathode side, there is still no consensus on whether carbon-based hosts will prove to be the best sulfur hosts for the industrialization of Li–S batteries. Recently, there has been controversy surrounding the use of carbon-based materials as the ideal sulfur hosts for practical applications of Li–S batteries under high sulfur loading and lean electrolyte conditions. To address this question, it is important to review the results of research into carbon-based hosts, assess their strengths and weaknesses, and provide a clear perspective. This review systematically evaluates the merits and mechanisms of various strategies for developing carbon-based host materials for high sulfur loading and lean electrolyte conditions. The review covers structural design and functional optimization strategies in detail, providing a comprehensive understanding of the development of sulfur hosts. The review also describes the use of efficient machine learning methods for investigating Li–S batteries. Finally, the outlook section lists and discusses current trends, challenges, and uncertainties surrounding carbon-based hosts, and concludes by presenting our standpoint and perspective on the subject.展开更多
Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to ...Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.展开更多
In this paper we show that two significant phenomena of magnetospheric chorus emission can be explained by the participation of beam-like electron structures,created by Landau-resonant interaction with growing oblique...In this paper we show that two significant phenomena of magnetospheric chorus emission can be explained by the participation of beam-like electron structures,created by Landau-resonant interaction with growing oblique whistler waves.The first concerns the widely observed spectral gap near half the electron cyclotron frequency Ωe;the second is related to the observation of very obliquely propagating lower-band waves that cannot be directly generated by temperature anisotropy.Concerning the gap,kinetic dispersion theory reveals that interference of the beam-related cyclotron mode ω~Ωe-kVb with the conventional whistler mode leads to mode splitting and the appearance of a ’forbidden’ area in the ω-k space.Thereby the beam velocity appears as an essential parameter.It is directly related to the phase velocity of the most unstable whistler wave mode,which is close to VAe/2 for sufficiently hot electrons(VAe is the electron Alfven velocity).To clarify the second point,we show that Landau-resonant beams with Vb Vb<VAe/2,which arise in cold plasmas from unstable upper-band waves,are able to generate lower-band whistler mode waves at very oblique propagation(θ≥60°).Our studies demonstrate the important role of Landau-resonant electrons in nonlinear whistler wave generation in the magnetosphere.展开更多
Genome editing is a valuable tool to target specific DNA sequences for mutagenesis in the genomes of microbes, plants, and animals. Although different genome editing technologies are available, the clustered regularly...Genome editing is a valuable tool to target specific DNA sequences for mutagenesis in the genomes of microbes, plants, and animals. Although different genome editing technologies are available, the clustered regularly interspaced short palindromic repeats/Cas9 （CRISPR/ Cas9） system, which utilizes engineered endonucleases to generate a double-stranded DNA break （DSB） in the target DNA region and subsequently stimulates site-specific mutagenesis through DNA repair machineries, is emerging as a powerful genome editing tool for elucidating mecha- nisms of protection from plant viruses, plant disease resistance, and gene functions in basic and applied research. In this review, we provide an overview of recent advances in the CRISPR system associated genome editing in plants by focusing on application of this technology in model plants, crop plants, fruit plants, woody plants and grasses and discuss how genome editing associated with the CRISPR system can provide insights into genome modifications and functional genomics in plants.展开更多
Background Persistence of slow pathway (SP) function after SP modification is not uncommon after successful rediofrequency (RF) ablation of typical AV nodal reentry tachycardia (AVNRT). Methods and results We compa...Background Persistence of slow pathway (SP) function after SP modification is not uncommon after successful rediofrequency (RF) ablation of typical AV nodal reentry tachycardia (AVNRT). Methods and results We compared two methods (maximal AH interval during decremental atrial stimlation vs occurrence of AV nodal echos or dual AV nodal physiology (DAVNP): ≥50 msec increment in AH interval with a 10 msec decrement in A1A2) for the assessment of SP function immediately and 40 minutes after successful RF modification of SP. In 31 consecutive patients (age: 51±16 years, 18 women, 13 men) with typical AVNRT, SP modification was performed using a combined anatomic and electrogram guided approach. Immediately after successful SP modification, AV nodal function was assessed. This was repeated 40 minutes later. RF modification of SP was successful in all 31 patients. There was no recurrance during a 5±3 month follow up period. There was no significant difference between the electrophysiological parameters immediately and University of Frankfurt, Germany (Li YG, Bogun F, Grnefeld G, Hohnloser SH and Goethe JW)40 min after successful SP modification. There was evidence of SP function in 14 patients (6 with DAVNP+AV nodal echoes, 8 with either DAVNP or AV nodal echos) immehiately after SP modification. These patients could be differentiated from the patients without remaining SP function by maximal AH interval (298±102 msec vs 198±72 msec, P=0.004). 40 minutes after the suucessful SP modification, 11 patients displayed SP function (4 patients with DAVNP+AV nodal echos, 7 patients with either DAVNP or AV nodal echos). These patients could also be differentiated from the remaining patients with the use of the maximal AH interval (294±89 msec vs 189±50 msec, P<0.001).[BHDFG3,WK9ZQ,WK6,WK10*2,WK5W]Befroe SP modificationImmediately after RF40 min after RF[BHDZG1*2,WK9ZQ,WK6,WK10*2,WK5W]AVNERP (msec)258±44310±116316±114AVBCL (msec)330±55384±113376±110VABCL (msec)306±67306± 66311±54Max AH (msec)337±96247±100233±86 Conclusion SP function assessed immediately and 40 minutes after a successful SP modification remains stable. SP function can be assessed reliable by maximal AH interval during decremental atrial stimulation.展开更多
In this workα-amylase was immobilized on magnetic Fe3O4 nanoparticles with polyethylenimine(PEI)/polydopamine(PDA)coating or 3-aminopropyl triethoxysilane(APTES)for the first time via adsorption–precipitation–cross...In this workα-amylase was immobilized on magnetic Fe3O4 nanoparticles with polyethylenimine(PEI)/polydopamine(PDA)coating or 3-aminopropyl triethoxysilane(APTES)for the first time via adsorption–precipitation–cross-linking.Compared with the freeα-amylase,the resultant magnetic cross-linkedα-amylase aggregates(PEI/PDA-M-CLEAs and N-M-CLEAs)exhibited excellent thermal and storage stability as well as pH stability.After storage at 25°C for 60 days,freeα-amylase only retained 60%of its initial activity,while PEI/PDA-M-CLEAs and N-M-CLEAs retained 80%and 78%of their initial activities,respectively.Furthermore,N-M-CLEAs and PEI/PDA-M-CLEAs showed good reusability.After 6 repeated uses,PEI/PDA-M-CLEAs and N-M-CLEAs still maintained 65%and 62%of their initial activities,respectively.Especially,PEI/PDA-M-CLEAs and N-M-CLEAs exhibited higher starch hydrolysis efficiency than freeα-amylase.The maximum dextrose equivalent(DE)values of starch hydrolysis by PEI/PDA-M-CLEAs and N-M-CLEAs reached 29.24%and 28.79%within 90 min,respectively.However,the maximum DE values of starch hydrolysis by the freeα-amylase was only 27.89%even in 150 min.The magnetic cross-linkedα-amylase aggregates could be introduced as effective biocatalyst for industrial applications in production of maltose syrups.展开更多
In this work,the fundamental mechanism of ultrabright fluorescence from surface-modified colloidal silicon quantum dots is investigated in depth using ultrafast spectroscopy.The underlying energy band structure corres...In this work,the fundamental mechanism of ultrabright fluorescence from surface-modified colloidal silicon quantum dots is investigated in depth using ultrafast spectroscopy.The underlying energy band structure corresponding to such highly efficient direct bandgap-like emissions in our surface-modified silicon quantum dots is unraveled by analyzing the transient optical spectrum,which demonstrates the significant effect of surface molecular engineering.It is observed that special surface modification,which creates novel surface states,is responsible for the different emission wavelengths and the significant improvement in the photoluminescence quantum yields.Following this essential understanding,surface-modified silicon quantum dots with deep blue to orange emission are successfully prepared without changing their sizes.展开更多
Gold nanorods(AuNRs)have attracted tremendous interest in biomedical fields due to their unique optical properties,tunable surface plasmon,and excellent biocompatibility.Their biomedical applications are mainly influe...Gold nanorods(AuNRs)have attracted tremendous interest in biomedical fields due to their unique optical properties,tunable surface plasmon,and excellent biocompatibility.Their biomedical applications are mainly influenced by near-infrared(NIR)light,which can guarantee deep penetration into human tissues with minimal loss.However,traditional single AuNRs are unable to carry medicine into the lesion regions.Furthermore,it is difficult for AuNR nanoparticles to be implemented in multimodal imagingguided synergetic therapy,which has limited the application of AuNRs in the field of theranostics.In recent years,researchers have made great strides in modifying gold nanorods into nanomaterials for the integration of diagnosis and treatment.After modifying different functionalized shells on the outsides of AuNRs,heterostructure AuNRs known as anisotropic gold nanorod(AAuNR)nanoparticles possessed bioimaging and cancer therapy abilities,as well as a variety of other amazing biomedical applications.In addition,AAuNR nanoparticles can combine biomedical imaging and therapy into one system to achieve multimodal bioimaging guided synergetic therapy.In this study,we presented a current review of the latest progress of different types of AAuNRs nanoparticles and their biomedical applications.Furthermore,the challenges and future development trends of AAuNR nanoparticles in the biomedical fields are discussed.展开更多
In this paper,the Discrete Least Squares Meshless(DLSM)method is developed to determine crack-tip fields.In DLSM,the problem domain and its boundary are discretized by unrelated field nodes used to introduce the shape...In this paper,the Discrete Least Squares Meshless(DLSM)method is developed to determine crack-tip fields.In DLSM,the problem domain and its boundary are discretized by unrelated field nodes used to introduce the shape functions by the moving least-squares(MLS)interpolant.This method aims to minimize the sum of squared residuals of the governing differential equations at any nodal point.Since high-continuity shape functions are used,some necessary treatments,including the visibility criterion,diffraction,and transparency approaches,are employed in the DLSM to introduce strong discontinuities such as cracks.The stress extrapolation and J-integral methods are used to calculate stress intensity factors.Three classic numerical examples using three approaches to defining discontinuities in the irregular distribution of nodal points are considered to investigate the effectiveness of the DLSM method.The numerical tests indicated that the proposed method effectively employed the approaches to defining discontinuities to deal with discontinuous boundaries.It was also demonstrated that the diffraction approach obtained higher accuracy than the other techniques.展开更多
基金support from EPSRC-New Investigator Award 2020 (EP/V002260/1)The Faraday Institute-Battery Study and Seed Research Project (FIRG052)+2 种基金The Royal Society-International Exchanges 2021 Cost Share (NSFC)(IECNSFC211074)the China Scholarship Council (CSC, No. 201806130168)the International Postdoctoral Exchange Fellowship Program (Grant No. PC2022020)
文摘As the need for high-energy–density batteries continues to grow, lithium-sulfur(Li–S) batteries have become a highly promising next-generation energy solution due to their low cost and exceptional energy density compared to commercially available Li-ion batteries. Research into carbon-based sulfur hosts for Li–S batteries has been ongoing for over two decades, leading to a significant number of publications and patents.However, the commercialization of Li–S batteries has yet to be realized. This can be attributed, in part, to the instability of the Li metal anode. However, even when considering just the cathode side, there is still no consensus on whether carbon-based hosts will prove to be the best sulfur hosts for the industrialization of Li–S batteries. Recently, there has been controversy surrounding the use of carbon-based materials as the ideal sulfur hosts for practical applications of Li–S batteries under high sulfur loading and lean electrolyte conditions. To address this question, it is important to review the results of research into carbon-based hosts, assess their strengths and weaknesses, and provide a clear perspective. This review systematically evaluates the merits and mechanisms of various strategies for developing carbon-based host materials for high sulfur loading and lean electrolyte conditions. The review covers structural design and functional optimization strategies in detail, providing a comprehensive understanding of the development of sulfur hosts. The review also describes the use of efficient machine learning methods for investigating Li–S batteries. Finally, the outlook section lists and discusses current trends, challenges, and uncertainties surrounding carbon-based hosts, and concludes by presenting our standpoint and perspective on the subject.
基金Funded by the Interdisciplinary Program of Shanghai Jiao Tong University(YG2016MS24)
文摘Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.
文摘In this paper we show that two significant phenomena of magnetospheric chorus emission can be explained by the participation of beam-like electron structures,created by Landau-resonant interaction with growing oblique whistler waves.The first concerns the widely observed spectral gap near half the electron cyclotron frequency Ωe;the second is related to the observation of very obliquely propagating lower-band waves that cannot be directly generated by temperature anisotropy.Concerning the gap,kinetic dispersion theory reveals that interference of the beam-related cyclotron mode ω~Ωe-kVb with the conventional whistler mode leads to mode splitting and the appearance of a ’forbidden’ area in the ω-k space.Thereby the beam velocity appears as an essential parameter.It is directly related to the phase velocity of the most unstable whistler wave mode,which is close to VAe/2 for sufficiently hot electrons(VAe is the electron Alfven velocity).To clarify the second point,we show that Landau-resonant beams with Vb Vb<VAe/2,which arise in cold plasmas from unstable upper-band waves,are able to generate lower-band whistler mode waves at very oblique propagation(θ≥60°).Our studies demonstrate the important role of Landau-resonant electrons in nonlinear whistler wave generation in the magnetosphere.
文摘Genome editing is a valuable tool to target specific DNA sequences for mutagenesis in the genomes of microbes, plants, and animals. Although different genome editing technologies are available, the clustered regularly interspaced short palindromic repeats/Cas9 （CRISPR/ Cas9） system, which utilizes engineered endonucleases to generate a double-stranded DNA break （DSB） in the target DNA region and subsequently stimulates site-specific mutagenesis through DNA repair machineries, is emerging as a powerful genome editing tool for elucidating mecha- nisms of protection from plant viruses, plant disease resistance, and gene functions in basic and applied research. In this review, we provide an overview of recent advances in the CRISPR system associated genome editing in plants by focusing on application of this technology in model plants, crop plants, fruit plants, woody plants and grasses and discuss how genome editing associated with the CRISPR system can provide insights into genome modifications and functional genomics in plants.
文摘Background Persistence of slow pathway (SP) function after SP modification is not uncommon after successful rediofrequency (RF) ablation of typical AV nodal reentry tachycardia (AVNRT). Methods and results We compared two methods (maximal AH interval during decremental atrial stimlation vs occurrence of AV nodal echos or dual AV nodal physiology (DAVNP): ≥50 msec increment in AH interval with a 10 msec decrement in A1A2) for the assessment of SP function immediately and 40 minutes after successful RF modification of SP. In 31 consecutive patients (age: 51±16 years, 18 women, 13 men) with typical AVNRT, SP modification was performed using a combined anatomic and electrogram guided approach. Immediately after successful SP modification, AV nodal function was assessed. This was repeated 40 minutes later. RF modification of SP was successful in all 31 patients. There was no recurrance during a 5±3 month follow up period. There was no significant difference between the electrophysiological parameters immediately and University of Frankfurt, Germany (Li YG, Bogun F, Grnefeld G, Hohnloser SH and Goethe JW)40 min after successful SP modification. There was evidence of SP function in 14 patients (6 with DAVNP+AV nodal echoes, 8 with either DAVNP or AV nodal echos) immehiately after SP modification. These patients could be differentiated from the patients without remaining SP function by maximal AH interval (298±102 msec vs 198±72 msec, P=0.004). 40 minutes after the suucessful SP modification, 11 patients displayed SP function (4 patients with DAVNP+AV nodal echos, 7 patients with either DAVNP or AV nodal echos). These patients could also be differentiated from the remaining patients with the use of the maximal AH interval (294±89 msec vs 189±50 msec, P<0.001).[BHDFG3,WK9ZQ,WK6,WK10*2,WK5W]Befroe SP modificationImmediately after RF40 min after RF[BHDZG1*2,WK9ZQ,WK6,WK10*2,WK5W]AVNERP (msec)258±44310±116316±114AVBCL (msec)330±55384±113376±110VABCL (msec)306±67306± 66311±54Max AH (msec)337±96247±100233±86 Conclusion SP function assessed immediately and 40 minutes after a successful SP modification remains stable. SP function can be assessed reliable by maximal AH interval during decremental atrial stimulation.
基金the Fundamental Research Funds for the Central Universities(grant No.226-2023-0085)the Science and Technology Program of Tianjin,China(grant No.20ZYJDJC00080)the International Collaboration Project(grant No.2020/37/K/ST8/03805).
文摘In this workα-amylase was immobilized on magnetic Fe3O4 nanoparticles with polyethylenimine(PEI)/polydopamine(PDA)coating or 3-aminopropyl triethoxysilane(APTES)for the first time via adsorption–precipitation–cross-linking.Compared with the freeα-amylase,the resultant magnetic cross-linkedα-amylase aggregates(PEI/PDA-M-CLEAs and N-M-CLEAs)exhibited excellent thermal and storage stability as well as pH stability.After storage at 25°C for 60 days,freeα-amylase only retained 60%of its initial activity,while PEI/PDA-M-CLEAs and N-M-CLEAs retained 80%and 78%of their initial activities,respectively.Furthermore,N-M-CLEAs and PEI/PDA-M-CLEAs showed good reusability.After 6 repeated uses,PEI/PDA-M-CLEAs and N-M-CLEAs still maintained 65%and 62%of their initial activities,respectively.Especially,PEI/PDA-M-CLEAs and N-M-CLEAs exhibited higher starch hydrolysis efficiency than freeα-amylase.The maximum dextrose equivalent(DE)values of starch hydrolysis by PEI/PDA-M-CLEAs and N-M-CLEAs reached 29.24%and 28.79%within 90 min,respectively.However,the maximum DE values of starch hydrolysis by the freeα-amylase was only 27.89%even in 150 min.The magnetic cross-linkedα-amylase aggregates could be introduced as effective biocatalyst for industrial applications in production of maltose syrups.
基金HBS thanks the Natural Science Foundation of China(NSFC)under Grant Nos.91423102,21273096,91323301 and 11104109the National Basic Research Program of China(973 Program)under Grant No.2014CB921302 for support.
文摘In this work,the fundamental mechanism of ultrabright fluorescence from surface-modified colloidal silicon quantum dots is investigated in depth using ultrafast spectroscopy.The underlying energy band structure corresponding to such highly efficient direct bandgap-like emissions in our surface-modified silicon quantum dots is unraveled by analyzing the transient optical spectrum,which demonstrates the significant effect of surface molecular engineering.It is observed that special surface modification,which creates novel surface states,is responsible for the different emission wavelengths and the significant improvement in the photoluminescence quantum yields.Following this essential understanding,surface-modified silicon quantum dots with deep blue to orange emission are successfully prepared without changing their sizes.
基金supported by the National Natural Science Foundation of China(Nos.U1505221,21635002,21874024,and 21475026,)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT15R11)+1 种基金the HealthEducation joint research project of Fujian Province(No.KJ2016-2-23)Young Thousand Talents Award,Minjiang Scholars of Fujian Province,and the Intramural Research Program(IRP)of the NIBIB,NIH.
文摘Gold nanorods(AuNRs)have attracted tremendous interest in biomedical fields due to their unique optical properties,tunable surface plasmon,and excellent biocompatibility.Their biomedical applications are mainly influenced by near-infrared(NIR)light,which can guarantee deep penetration into human tissues with minimal loss.However,traditional single AuNRs are unable to carry medicine into the lesion regions.Furthermore,it is difficult for AuNR nanoparticles to be implemented in multimodal imagingguided synergetic therapy,which has limited the application of AuNRs in the field of theranostics.In recent years,researchers have made great strides in modifying gold nanorods into nanomaterials for the integration of diagnosis and treatment.After modifying different functionalized shells on the outsides of AuNRs,heterostructure AuNRs known as anisotropic gold nanorod(AAuNR)nanoparticles possessed bioimaging and cancer therapy abilities,as well as a variety of other amazing biomedical applications.In addition,AAuNR nanoparticles can combine biomedical imaging and therapy into one system to achieve multimodal bioimaging guided synergetic therapy.In this study,we presented a current review of the latest progress of different types of AAuNRs nanoparticles and their biomedical applications.Furthermore,the challenges and future development trends of AAuNR nanoparticles in the biomedical fields are discussed.
文摘In this paper,the Discrete Least Squares Meshless(DLSM)method is developed to determine crack-tip fields.In DLSM,the problem domain and its boundary are discretized by unrelated field nodes used to introduce the shape functions by the moving least-squares(MLS)interpolant.This method aims to minimize the sum of squared residuals of the governing differential equations at any nodal point.Since high-continuity shape functions are used,some necessary treatments,including the visibility criterion,diffraction,and transparency approaches,are employed in the DLSM to introduce strong discontinuities such as cracks.The stress extrapolation and J-integral methods are used to calculate stress intensity factors.Three classic numerical examples using three approaches to defining discontinuities in the irregular distribution of nodal points are considered to investigate the effectiveness of the DLSM method.The numerical tests indicated that the proposed method effectively employed the approaches to defining discontinuities to deal with discontinuous boundaries.It was also demonstrated that the diffraction approach obtained higher accuracy than the other techniques.
