Spinal cord injury(SCI)is a debilitating ailment that leads to the loss of motor and sensory functions,often leaving the patient paralyzed below the injury site(Chen et al.,2013).Globally around 250,000-300,000 people...Spinal cord injury(SCI)is a debilitating ailment that leads to the loss of motor and sensory functions,often leaving the patient paralyzed below the injury site(Chen et al.,2013).Globally around 250,000-300,000 people are diagnosed with SCI annually(Singh et al.,2014),and while this number appears quite low,the effect that an SCI has on the patient’s quality of life is drastic,due to the current difficulties to comprehensively treat this illness.The cost of patient care can also be quite costly,amounting to an estimated$1.69 billion in healthcare costs in the USA alone(Mahabaleshwarkar and Khanna,2014).展开更多
Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications.Interestingly,it can also be able to convert mechanical and thermal energy into electricity due to its pi...Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications.Interestingly,it can also be able to convert mechanical and thermal energy into electricity due to its piezo-and pyroelectric nature.Here,we demonstrate engineering of lysozyme into piezoelectric devices that can exploit the potential of lysozyme as environmentally friendly,biocompatible material for mechanical energy harvesting and sensorics,especially in micropowered electronic applications.Noteworthy that this flexible,shape adaptive devices made of crystalline lysozyme obtained from hen egg white exhibited a longitudinal piezoelectric charge coefficient(d-2.7 pC N^(-1))and piezoelectric voltage coefficient(g-76.24 mVmN^(-1))which are comparable to those of quartz(-2.3 pC N^(-1) and 50 mVmN^(-1)).Simple finger tapping on bio-organic energy harvester(BEH)made of lysozyme produced up to 350 mV peak-to-peak voltage,and a maximum instantaneous power output of 2.2 nW cm^(-2).We also demonstrated that the BEH could be used for self-powered motion sensing for real-time monitoring of different body functions.These results pave the way toward self-powered,autonomous,environmental-friendly bio-organic devices for flexible energy harvesting,storage,and in wearable healthcare monitoring.展开更多
Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue regeneration.In this study,we developed a poly(2-hydroxyethyl me...Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue regeneration.In this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHEMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PEDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)printing.The presence of the NPs was critical as they altered the rheological properties during printing.However,all samples exhibited suitable shear thinning properties,allowing for the development of an optimized processing window for 3D printing.Samples were 3D printed into pre-determined disk-shaped configurations of 2 and 10 mm in height and diameter,respectively.We observed that the NPs disrupted the gel crosslinking efficiencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 kPa.The conductivity of the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/cm.In vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHEMA-co-MAA NP hydrogels yielded high cellular viability and proliferation rates.Finally,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels affected bacterial growth.Taken together,these materials show promise for various TE strategies.展开更多
Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high e...Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.展开更多
Silicon nanowires(Si NWs)have been widely researched as the best alternative to graphite anodes for the next-generation of high-performance lithium-ion batteries(LIBs)owing to their high capacity and low discharge pot...Silicon nanowires(Si NWs)have been widely researched as the best alternative to graphite anodes for the next-generation of high-performance lithium-ion batteries(LIBs)owing to their high capacity and low discharge potential.However,growing binder-free Si NW anodes with adequate mass loading and stable capacity is severely limited by the low surface area of planar current collectors(CCs),and is particularly challenging to achieve on standard pure-Cu substrates due to the ubiquitous formation of Li+inactive silicide phases.Here,the growth of densely-interwoven In-seeded Si NWs is facilitated by a thin-film of copper-silicide(CS)network in situ grown on a Cu-foil,allowing for a thin active NW layer(<10μm thick)and high areal loading(≈1.04 mg/cm^(2))binder-free electrode architecture.The electrode exhibits an average Coulombic efficiency(CE)of>99.6%and stable performance for>900 cycles with≈88.7%capacity retention.More significantly,it delivers a volumetric capacity of≈1086.1 m A h/cm^(3)at 5C.The full-cell versus lithium manganese oxide(LMO)cathode delivers a capacity of≈1177.1 m A h/g at 1C with a stable rate capability.This electrode architecture represents significant advances toward the development of binder-free Si NW electrodes for LIB application.展开更多
A novel continuous plastic process employed on AZ31 Mg alloy called closed forging extrusion(CFE)was presented.The optical microscopy,scanning electron microscopy,electron back-scatter diffraction and tensile and comp...A novel continuous plastic process employed on AZ31 Mg alloy called closed forging extrusion(CFE)was presented.The optical microscopy,scanning electron microscopy,electron back-scatter diffraction and tensile and compressive tests were employed to investigate the microstructure evolution and strengthening mechanism.The results indicated that the CFE-process can promote dynamic recrystallization(DRX),eliminate the coarsen unDRXed grain regions,refine the grains effectively,and improve the strength,plasticity and anisotropy of the alloy.The grain refinement was mainly attributed to the stress,which facilitated the nucleation of recrystallization and refined the microstructure via the CFE.The fully DRXed ultrafine grained structure improved the strength and plasticity simultaneously.After 60 s closed forging and continuous extrusion,the alloy exhibits relatively high TYS,UTS,CYS,elongation and yield asymmetry of 305 MPa,337 MPa,295 MPa,27%and 0.97,respectively.展开更多
Mg−9Al−1Zn(AZ91)magnesium matrix composites reinforced by Ti−6Al−4V(TC4)particles were successfully prepared via powder metallurgical method.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)show...Mg−9Al−1Zn(AZ91)magnesium matrix composites reinforced by Ti−6Al−4V(TC4)particles were successfully prepared via powder metallurgical method.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)showed a mountain-like tendency with the increase of the TC4 content.The mechanical properties of AZ91 magnesium matrix composites reached the optimal point with TC4 content of 10 wt.%,realizing YS,UTS,and EL of 335 MPa,370 MPa,and 6.4%,respectively.The improvement of mechanical properties can be attributed to the effective load transfer from the magnesium matrix to the TC4 particles,dislocations associated with the difference in the coefficient of thermal expansion,good interfacial bonding between the Mg matrix and TC4 particles,and grain refinement strengthening.展开更多
Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium cathodes.In p...Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium cathodes.In present work,we used hybrid ion strategy to analyze the performance of lithium titanate based lithium cathode,magnesium metal anode,and all-phenyl complex(APC)electrolytes at different temperatures(25℃,10℃,0℃,-10℃,and-20℃).The hybrid ion battery exhibited excellent rate performance(228 m Ah g^(-1)/20 m A g^(-1) and 163 mAh g^(-1)/1000 mA g^(-1))with stable voltage plateaus at 0.90 and 0.75 V,which corresponds to specific energy of 178 Wh kg^(-1) at room temperature(25℃).Experimental results revealed that APC-THF solutions have strong potential to suppress the freezing of electrolyte solutions owing to low boiling point of THF.The low temperature electrochemical testing revealed the reversible capacities of 213.4,165.5,143.8,133.2 and 78.56 mAh g^(-1) at 25,10,0,-10,and-20℃,respectively.Furthermore,ex-situ XRD,SEM,and EIS tests were carried out to understand the reaction kinetics of both Mg2+and Li+ions inside the lithium titanate cathode.We hope this work will shed light on low temperature prospective of electrochemical devices for use in cold environments.展开更多
Many evolved biomolecular functions such as ion pumping or redox catalysis rely on controlled charge transport through the polypeptide matrix, which can be regulated by shifts in molecular protonation states and depen...Many evolved biomolecular functions such as ion pumping or redox catalysis rely on controlled charge transport through the polypeptide matrix, which can be regulated by shifts in molecular protonation states and dependent supramolecular packing modes in response to environmental cues. However, the exact roles of such dynamic, non-covalent interactions in peptide charge transport have remained elusive. To tackle this challenge, here we report the modulation of charge transport in a series of lysine(Lys)-substituted hepta-glycine(Gly) peptide self-assembled monolayers(SAMs) on template-striped gold(Au^(TS)) bottom electrodes with eutectic gallium-indium(EGaIn) liquid metal top electrodes. We demonstrate systematic modulation of hydrogen bonding and more general electrostatic interactions by shifting the position of the charged Lys-residue and creating different protonation patterns by changing the environmental pH in the Au^(TS)/peptide//Ga Ox/EGa In junctions. The effective modulation is evidenced by current density-voltage(J-V) measurements combined with SAM characterization using ultraviolet photoelectron spectroscopy(UPS) and angle-resolved X-ray photoelectron spectroscopy(ARXPS), polarization modulation-infrared reflection-absorption spectroscopy(PM-IRRAS), and molecular dynamics(MD) simulations. Decreasing the hydrogen bonding inside the peptide SAMs and increasing the electrostatic interactions by environmental counterions amplifies the charge transport differently with Lys-position, which means that the sensitive electrical response of peptide SAMs can be tuned by the peptide sequence. Our results provide insights into the relationship between molecular design and in situ modulation of charge transport properties for the development of bionanoelectronics.展开更多
Vectored non-covalent interactions—mainly hydrogen bonding and aromatic interactions—extensively contribute to(bio)-organic self-assembling processes and significantly impact the physicochemical properties of the as...Vectored non-covalent interactions—mainly hydrogen bonding and aromatic interactions—extensively contribute to(bio)-organic self-assembling processes and significantly impact the physicochemical properties of the associated superstructures.However,vectored non-covalent interaction-driven assembly occursmainly along one-dimensional(1D)or three-dimensional(3D)directions,and a two-dimensional(2D)orientation,especially that of multilayered,graphene-like assembly,has been reported less.In this present research,by introducing amino,hydroxyl,and phenyl moieties to the triazine skeleton,supramolecular layered assembly is achieved by vectored non-covalent interactions.The planar hydrogen bonding network results in high stability,with a thermal sustainability of up to about 330°C and a Young’s modulus of up to about 40 GPa.Upon introducing wrinkles by biased hydrogen bonding or aromatic interactions to disturb the planar organization,the stability attenuates.However,the intertwined aromatic interactions prompt a red edge excitation shift effect inside the assemblies,inducing broad-spectrum fluorescence covering nearly the entire visible light region(400–650 nm).We show that bionic,superhydrophobic,pillar-like arrays with contact angles of up to about 170°can be engineered by aromatic interactions using a physical vapor deposition approach,which cannot be realized through hydrogen bonding.Our findings show the feasibility of 2D assembly with engineerable properties by modulating vectored non-covalent interactions.展开更多
The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated tempera...The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated temperatures,has hindered the widespread use of these materials in industrial applications.This paper took this challenge to break through the above established relationship by developing novel nacrelike multilayered Mo_(2)N–SiN_(x)/Ag–SiN_(x)self-lubricant films via an radio frequency(RF)magnetron sputtering system for real applications where harsh conditions at elevated temperatures exist.The multilayered films,deposited by alternating deposition of Mo_(2)N–SiN_(x)and Ag–SiN_(x)modulation layers,exhibited three phases of face-centered cubic(fcc)Mo_(2)N,fcc Ag and SiN_(x),where SiN_(x)encapsulated the nano-crystalline Mo_(2)N and Ag phases in each layer to successfully induce a“brick and mortar”nacre-like microstructure(in the area without the coherent structure).The epitaxy growth of the Ag–SiN_(x)layers with thickness below 6 nm on the Mo_(2)N template resulted in an extraordinary increase in both the hardness and elastic modulus,which was able to prevent severe degradation of the mechanical properties caused by the addition of Ag.The room-temperature anti-friction property could be enhanced by increasing the Ag–SiN_(x)layer thickness due to the excellent lubricant nature of Ag,which acts in synergy with Mo_(2)N,while the wear rate below 4×10^(−8)mm^(3)/(N·mm)was due to the high mechanical strength.The tribological properties at 600℃also benefited from the interlocked multilayered architecture,which allowed an extreme low friction coefficient of~0.12 and a negligible wear rate(WR).This behavior was attributed to the synergism between the lubricant action of Ag and Mo_(2)N and the tribo-phase transformation from Ag_(2)Mo_(4)O_(13)to Ag_(2)MoO_(4).展开更多
Industrial purification processes for ethylene from steam pyrolysis or cracking gases generally employ multiple energy-intensive steps to remove C_(2)H_(2),C_(2)H_(6),CO_(2),and C_(3) hydrocarbons.Designing multifunct...Industrial purification processes for ethylene from steam pyrolysis or cracking gases generally employ multiple energy-intensive steps to remove C_(2)H_(2),C_(2)H_(6),CO_(2),and C_(3) hydrocarbons.Designing multifunctional molecular separators that integrate multiple structural characteristics capable of removing several impurities simultaneously is highly desired but not yet realized.Here,we address this challenge using a custom-designed multifunctional,and industry-compatible ultramicroporous crystalline physisorbent(CALF-20)to purify C_(2)H_(4) from a seven-component cracking gas mixture(C_(2)H_(4),C_(2)H_(2),C_(2)H_(6),CO_(2),C_(3)H_(4),C_(3)H_(6),and C_(3)H8)by one-step separation with remarkable performance.Verified by breakthrough experiments,C_(2)H_(4)(>99.99%)can be recovered not only from binary C_(2)H_(6)/C_(2)H_(4)(50/50),ternary C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)(33/33/33),and quaternary C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)/CO_(2)(25/25/25/25)mixtures,but also from a typical seven-component gas cracking mixture of C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)/CO_(2)/C_(3)H_(4)/C_(3)H_(6)/C_(3)H8(0.6/62/10/0.3/0.6/26/0.5),even at the high humidity of 74%.Notably,CALF-20 can be easily produced on the kilogram scale,showing great commercial application potential.Together with its framework flexibility and appropriate pore geometry,CALF-20 exhibits a sorbent-sorbate induced-fit behavior strengthening multiple specific recognition sites for the corresponding vips,validated by single-crystal X-ray diffraction study and molecular modeling.This work is the first example of using a single physisorbent to purify C_(2)H_(4) from a seven-component cracking gas mixture and opens an avenue to address complicated hydrocarbon mixture separation challenges.展开更多
This review paper explores the cutting-edge advancements in hydrogel design for articular cartilage regeneration(CR).Articular cartilage(AC)defects are a common occurrence worldwide that can lead to joint breakdown at...This review paper explores the cutting-edge advancements in hydrogel design for articular cartilage regeneration(CR).Articular cartilage(AC)defects are a common occurrence worldwide that can lead to joint breakdown at a later stage of the disease,necessitating immediate intervention to prevent progressive degeneration of cartilage.Decades of research into the biomedical applications of hydrogels have revealed their tremendous potential,particularly in soft tissue engineering,including CR.Hydrogels are highly tunable and can be designed to meet the key criteria needed for a template in CR.This paper aims to identify those criteria,including the hydrogel components,mechanical properties,biodegradability,structural design,and integration capability with the adjacent native tissue and delves into the benefits that CR can obtain through appropriate design.Stratifiedstructural hydrogels that emulate the native cartilage structure,as well as the impact of environmental stim-uli on the regeneration outcome,have also been discussed.By examining recent advances and emerging tech-niques,this paper offers valuable insights into developing effective hydrogel-based therapies for AC repair.展开更多
Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and i...Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and intermediate stabilization. It is imperative to elucidate the mechanism for such an influence towards the rational design of efficient catalysts;however, the complex interactions between the multiple factors involved in the system make it challenging to establish a clear structure–performance relationship. In this work, we chose ion-intercalated silver(I)-based coordination networks(AgCNs) with a well-defined structure as a model platform, which enables us to understand the regulation mechanism of counterions as the counterions are the only tuning factor involved in such a system. We prepared two isostructural Ag CNs with different intercalation ions or counterions of BF_(4)^(-) and ClO_(4)^(-)(named as AgCNs-BF_(4) and AgCNs-ClO_(4)) and found that the former has a more competitive CO_(2) electroreduction performance than the latter. AgCNs-BF_(4) achieves the highest Faradaic efficiency for CO_(2) to CO of 87.1% at-1.0 V(vs. RHE) with a higher partial current density, while AgCNs-ClO_(4) exhibits only 77.2% at the same applied potential.Spectroscopic characterizations and theoretical calculation reveal that the presence of BF_(4)^(-)is more favorable for stabilizing the COOH^(*) intermediate by weakening hydrogen bonds, which accounts for the superior activity of Ag CNs-BF_(4).展开更多
The relationships between hyaluronic acid(HA)and pathological microorganisms incite new understandings on microbial infection,tissue penetration,disease progression and lastly,potential treatments.These understandings...The relationships between hyaluronic acid(HA)and pathological microorganisms incite new understandings on microbial infection,tissue penetration,disease progression and lastly,potential treatments.These understandings are important for the advancement of next generation antimicrobial therapeutical strategies for the control of healthcare-associated infections.Herein,this review will focus on the interplay between HA,bacteria,fungi,and viruses.This review will also comprehensively detail and discuss the antimicrobial activity displayed by various HA molecular weights for a variety of biomedical and pharmaceutical applications,including microbiology,pharmaceutics,and tissue engineering.展开更多
Graphene oxide (GO) possesses excellent mechanical strength,biocompatibility,colloidal stability,large surface area and high adsorption capability.It has driven to cancer nanotechnology to defeat cancer therapy obstac...Graphene oxide (GO) possesses excellent mechanical strength,biocompatibility,colloidal stability,large surface area and high adsorption capability.It has driven to cancer nanotechnology to defeat cancer therapy obstacles,via integration into three-dimensional (3D) hydrogel network with biocompatible polymers as nanocomposites carrier,and controllable release of anticancer drugs.Specifically,the surface of GO affords π-π stacking and hydrophilic interactions with anticancer drugs.Additionally,modification of GO with various polymers such as natural and synthetic polymers enhances its biodegradability,drug loading,and target delivery.In this review,GO based hydrogels research accomplishments are reviewed on the aspects of crosslinking strategies,preparation methods,the model drug,polymer conjugation and modification with targeting ligands.Moreover,swelling kinetics,drug release profile and biological activity in vivo and in vitro are discussed.The biocompatibility of GO based hydrogels is also discussed from the perspective of its nano-bio interfaces.Apart from that,the clinical potential of GO based hydrogels and its major challenges are addressed in detail.Finally,this review concludes with a summary and invigorating future perspectives of GO based hydrogels for anticancer drug delivery.It is anticipated that this review can stimulate a new research gateway to facilitate the development of anticancer drug delivery by harnessing the unique properties of GO based hydrogels,such as large surface area,chemical purity,high loading capacity of drug,chemical stability,and the nature of lipophilic for cell membrane penetration.展开更多
Second harmonic generation and sum frequency generation(SHG and SFG)provide effective means to realize coherent light at desired frequencies when lasing is not easily achievable.They have found applications from sensi...Second harmonic generation and sum frequency generation(SHG and SFG)provide effective means to realize coherent light at desired frequencies when lasing is not easily achievable.They have found applications from sensing to quantum optics and are of particular interest for integrated photonics at communication wavelengths.Decreasing the footprints of nonlinear components while maintaining their high up-conversion efficiency remains a challenge in the miniaturization of integrated photonics.Here we explore lithographically defined AlGaInP nano(micro)structures/Al_(2)O_(3)/Ag as a versatile platform to achieve efficient SHG/SFG in both waveguide and resonant cavity configurations in both narrow-and broadband infrared(IR)wavelength regimes(1300-1600 nm).The effective excitation of highly confined hybrid plasmonic modes at fundamental wavelengths allows efficient SHG/SFG to be achieved in a waveguide of a cross-section of 113 nm×250 nm,with a mode area on the deep subwavelength scale(λ2/135)at fundamental wavelengths.Remarkably,we demonstrate direct visualization of SHG/SFG phase-matching evolution in the waveguides.This together with mode analysis highlights the origin of the improved SHG/SFG efficiency.We also demonstrate strongly enhanced SFG with a broadband IR source by exploiting multiple coherent SFG processes on 1μm diameter AlGaInP disks/Al_(2)O_(3)/Ag with a conversion efficiency of 14.8%MW^(−1) which is five times the SHG value using the narrowband IR source.In both configurations,the hybrid plasmonic structures exhibit>1000 enhancement in the nonlinear conversion efficiency compared to their photonic counterparts.Our results manifest the potential of developing such nanoscale hybrid plasmonic devices for state-of-the-art on-chip nonlinear optics applications.展开更多
Ferroelectricity in biological system has been anticipated both theoretically and experimentally over the past few decades.Claims of ferroelectricity in biological systems have given rise to confusion and methodologic...Ferroelectricity in biological system has been anticipated both theoretically and experimentally over the past few decades.Claims of ferroelectricity in biological systems have given rise to confusion and methodological controversy.Over the years,a“loop”of induced polarization in response to a varying applied electrical field and a consequent polarization reversal has prompted many researchers to claim ferroelectricity in biological structures and their building blocks.Other observers were skeptical about the methodology adopted in generating the data and questioned the validity of the claimed ferroelectricity as such,“loop”can also be obtained from linear capacitors.In a paper with somewhat tongue-in-cheek title,Jim Scott showed that ordinary banana peels could exhibit closed loops of electrical charge which closely resemble and thus could be misinterpreted as ferroelectric hysteresis loops in barium sodium niobate,BNN paraphrasing it as“banana”.In this paper,we critically review ferroelectricity in biological system and argue that knowing the molecular and crystalline structure of biological building blocks and experimenting on such building blocks may be the way forward in revealing the“true”nature of ferroelectricity in biological systems.展开更多
Solid polymer electrolytes have demonstrated high promise to solve the safety problems caused by conventional liquid electrolytes in lithium ion batteries.However,the inherent flammability of most polymer electrolyte ...Solid polymer electrolytes have demonstrated high promise to solve the safety problems caused by conventional liquid electrolytes in lithium ion batteries.However,the inherent flammability of most polymer electrolyte materials remains unresolved,hence hindering their further industrial application.Addressing this challenge,we designed and constructed a thermal-responsive imide-linked covalent organic framework(COF)bearing ortho-positioned hydroxy groups as precursors,which can conduct a thermal rearrangement to transform into a highly crystalline and robust benzoxazole-linked COF upon heating.Benefiting from the release of carbon dioxide through thermal rearrangement reaction,this COF platform exhibited excellent flame retardant properties.By contrast,classic COFs(e.g.,boronate ester,imine,olefin,imide linked)were all flammable.Moreover,incorpo-rating polyethylene glycol and Li salt into the COF channels can produce solid polymer electrolytes with outstanding flame retardancy,high ionic conductivity(6.42×10^(-4) S cm^(-1))and a high lithium-ion transference number of 0.95.This thermal rearrangement strategy not only opens a new route for the fabrication of ultrastable COFs,but also provides promising perspectives to designing flame-retardant materials for energy-related applications.展开更多
2D materials are considered for applications that require strong light-matter interaction because of the apparently giant oscillator strength of the exciton transitions in the absorbance spectrum.Nevertheless,the effe...2D materials are considered for applications that require strong light-matter interaction because of the apparently giant oscillator strength of the exciton transitions in the absorbance spectrum.Nevertheless,the effective oscillator strengths of these transitions have bee n scarcely reported,nor is there a con sistent interpretati on of the obtained values.Here,we analyse the transition dipole moment and the ensuing oscillator strength of the exciton transition in 2D CdSe nanoplatelets by means of the optically induced Stark effect(OSE).Intriguingly,we find that the exciton absorption line reacts to a high intensity optical field as a transition with an oscillator strength FStark that is 50 times smaller than expected based on the linear absorption coefficient.We propose that the pronounced exciton absorption line should be seen as the sum of multiple,low oscillator strength transitions,rather than a single high oscillator strength one,a feat we assign to strong exciton center-of-mass localization.Within the quantum mechanical description of excitons,this 50-fold difference between both oscillator strengths corresponds to the ratio between the cohere nee area of the exciton's center of mass and the total area,which yields a coherence area of a mere 6.1 nm2.Since we find that the coherence area in creases with reducing temperature,we conclude that thermal effects,related to lattice vibrations,contribute to exciton localization.In further support of this localization model,we show that FStark is in dependent of the n anoplatelet area,correctly predicts the radiative lifetime,and lines up for strongly confined quantum dot systems.展开更多
基金supported by the Irish Research Council under the Government of Ireland Postdoctoral Fellowship Project ID-GOIPD/2023/1431(to AS).
文摘Spinal cord injury(SCI)is a debilitating ailment that leads to the loss of motor and sensory functions,often leaving the patient paralyzed below the injury site(Chen et al.,2013).Globally around 250,000-300,000 people are diagnosed with SCI annually(Singh et al.,2014),and while this number appears quite low,the effect that an SCI has on the patient’s quality of life is drastic,due to the current difficulties to comprehensively treat this illness.The cost of patient care can also be quite costly,amounting to an estimated$1.69 billion in healthcare costs in the USA alone(Mahabaleshwarkar and Khanna,2014).
基金supported by CURAM-Science Foundation Ireland(SFI)center for medical devices(Grant Number 13/RC/2073_P2)Irish Research Council Postdoctoral Fellowship(GOIPD/2021/928):Disposable,biodegradable,endoscopic ultrasonic imaging probe(DISPOSON)+1 种基金SFI Opportunistic Fund(no.12/RI/2345/SOF)is acknowledged for the NTEGRA Hybrid Nanoscope used in Piezoresponse Force MicroscopyOpen access funding provided by IReL.
文摘Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications.Interestingly,it can also be able to convert mechanical and thermal energy into electricity due to its piezo-and pyroelectric nature.Here,we demonstrate engineering of lysozyme into piezoelectric devices that can exploit the potential of lysozyme as environmentally friendly,biocompatible material for mechanical energy harvesting and sensorics,especially in micropowered electronic applications.Noteworthy that this flexible,shape adaptive devices made of crystalline lysozyme obtained from hen egg white exhibited a longitudinal piezoelectric charge coefficient(d-2.7 pC N^(-1))and piezoelectric voltage coefficient(g-76.24 mVmN^(-1))which are comparable to those of quartz(-2.3 pC N^(-1) and 50 mVmN^(-1)).Simple finger tapping on bio-organic energy harvester(BEH)made of lysozyme produced up to 350 mV peak-to-peak voltage,and a maximum instantaneous power output of 2.2 nW cm^(-2).We also demonstrated that the BEH could be used for self-powered motion sensing for real-time monitoring of different body functions.These results pave the way toward self-powered,autonomous,environmental-friendly bio-organic devices for flexible energy harvesting,storage,and in wearable healthcare monitoring.
基金research conducted with the financial support of Science Foundation Ireland under the SFI Research Infrastructure Programme (21/RI/9831)the funding provided by the Irish Research Council through the Irish Research Council Enterprise Partnership Scheme with Johnson and Johnson (EPSPG/2020/78)
文摘Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue regeneration.In this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHEMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PEDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)printing.The presence of the NPs was critical as they altered the rheological properties during printing.However,all samples exhibited suitable shear thinning properties,allowing for the development of an optimized processing window for 3D printing.Samples were 3D printed into pre-determined disk-shaped configurations of 2 and 10 mm in height and diameter,respectively.We observed that the NPs disrupted the gel crosslinking efficiencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 kPa.The conductivity of the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/cm.In vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHEMA-co-MAA NP hydrogels yielded high cellular viability and proliferation rates.Finally,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels affected bacterial growth.Taken together,these materials show promise for various TE strategies.
基金Projects(41877551,41842020)supported by the National Natural Science Foundation of ChinaProject supported by the Science Foundation Ireland 17/CDA/4778
文摘Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.
基金funded by the Science Foundation Ireland (SFI)under the Principal Investigator Program under contract No.11PI-1148,16/IA/4629 and SFI 16/M-ERA/3419funding under the European Union’s Horizon 2020 Research and Innovation Program+7 种基金grant agreement No.814464 (Si-DRIVE project)IRCLA/2017/285 and SFI Research Centres AMBER,Ma REI and CONFIRM 12/RC/2302_P2,12/RC/2278_P2,and 16/RC/3918SFI for SIRG grant No.18/SIRG/5484support from the Sustainable Energy Authority of Ireland through the Research Development and Demonstration Funding Program (Grant No.19/RDD/548)Enterprise Ireland through the Innovation Partnership Program (Grant No.IP 20190910)support from the SFI Research Centre Ma REI (award reference No.12/RC/2302_P2)support from the SFI Industry RD&I Fellowship Program (21/IRDIF/9876)the EU Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Individual Fellowship Grant (843621)。
文摘Silicon nanowires(Si NWs)have been widely researched as the best alternative to graphite anodes for the next-generation of high-performance lithium-ion batteries(LIBs)owing to their high capacity and low discharge potential.However,growing binder-free Si NW anodes with adequate mass loading and stable capacity is severely limited by the low surface area of planar current collectors(CCs),and is particularly challenging to achieve on standard pure-Cu substrates due to the ubiquitous formation of Li+inactive silicide phases.Here,the growth of densely-interwoven In-seeded Si NWs is facilitated by a thin-film of copper-silicide(CS)network in situ grown on a Cu-foil,allowing for a thin active NW layer(<10μm thick)and high areal loading(≈1.04 mg/cm^(2))binder-free electrode architecture.The electrode exhibits an average Coulombic efficiency(CE)of>99.6%and stable performance for>900 cycles with≈88.7%capacity retention.More significantly,it delivers a volumetric capacity of≈1086.1 m A h/cm^(3)at 5C.The full-cell versus lithium manganese oxide(LMO)cathode delivers a capacity of≈1177.1 m A h/g at 1C with a stable rate capability.This electrode architecture represents significant advances toward the development of binder-free Si NW electrodes for LIB application.
基金funded by the National Natural Science Foundation of China (Nos. 51971042, 51901028)the Fundamental Research Funds for the Central Universities Project, China (No. 2021CDJQY-038)the Chongqing Academician Special Fund, China (Nos. cstc2018jcyj-yszxX0007, cstc2019yszx-jcyjX0004)
文摘A novel continuous plastic process employed on AZ31 Mg alloy called closed forging extrusion(CFE)was presented.The optical microscopy,scanning electron microscopy,electron back-scatter diffraction and tensile and compressive tests were employed to investigate the microstructure evolution and strengthening mechanism.The results indicated that the CFE-process can promote dynamic recrystallization(DRX),eliminate the coarsen unDRXed grain regions,refine the grains effectively,and improve the strength,plasticity and anisotropy of the alloy.The grain refinement was mainly attributed to the stress,which facilitated the nucleation of recrystallization and refined the microstructure via the CFE.The fully DRXed ultrafine grained structure improved the strength and plasticity simultaneously.After 60 s closed forging and continuous extrusion,the alloy exhibits relatively high TYS,UTS,CYS,elongation and yield asymmetry of 305 MPa,337 MPa,295 MPa,27%and 0.97,respectively.
基金Acknowledgments The authors acknowledge the financial support from the Guangdong Major Project of Basic and Applied Basic Research,China(No.2020B0301030006)the National Natural Science Foundation of China(Nos.52171133,52171103)+1 种基金the“111 Project”by the Ministry of Education of China(No.B16007)Fundamental Research Fund of Central Universities in China(No.2018CDJDCL0019)。
文摘Mg−9Al−1Zn(AZ91)magnesium matrix composites reinforced by Ti−6Al−4V(TC4)particles were successfully prepared via powder metallurgical method.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)showed a mountain-like tendency with the increase of the TC4 content.The mechanical properties of AZ91 magnesium matrix composites reached the optimal point with TC4 content of 10 wt.%,realizing YS,UTS,and EL of 335 MPa,370 MPa,and 6.4%,respectively.The improvement of mechanical properties can be attributed to the effective load transfer from the magnesium matrix to the TC4 particles,dislocations associated with the difference in the coefficient of thermal expansion,good interfacial bonding between the Mg matrix and TC4 particles,and grain refinement strengthening.
基金JUST Research Start-Up Fund(1062921905)supported。
文摘Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium cathodes.In present work,we used hybrid ion strategy to analyze the performance of lithium titanate based lithium cathode,magnesium metal anode,and all-phenyl complex(APC)electrolytes at different temperatures(25℃,10℃,0℃,-10℃,and-20℃).The hybrid ion battery exhibited excellent rate performance(228 m Ah g^(-1)/20 m A g^(-1) and 163 mAh g^(-1)/1000 mA g^(-1))with stable voltage plateaus at 0.90 and 0.75 V,which corresponds to specific energy of 178 Wh kg^(-1) at room temperature(25℃).Experimental results revealed that APC-THF solutions have strong potential to suppress the freezing of electrolyte solutions owing to low boiling point of THF.The low temperature electrochemical testing revealed the reversible capacities of 213.4,165.5,143.8,133.2 and 78.56 mAh g^(-1) at 25,10,0,-10,and-20℃,respectively.Furthermore,ex-situ XRD,SEM,and EIS tests were carried out to understand the reaction kinetics of both Mg2+and Li+ions inside the lithium titanate cathode.We hope this work will shed light on low temperature prospective of electrochemical devices for use in cold environments.
基金supported by the National Natural Science Foundation of China(Nos.21974102 and 21705019)the National Key R&D Program of China(No.2018YFA0703700)support from Science Foundation Ireland(SFI,No.12/RC/2275_P2)。
文摘Many evolved biomolecular functions such as ion pumping or redox catalysis rely on controlled charge transport through the polypeptide matrix, which can be regulated by shifts in molecular protonation states and dependent supramolecular packing modes in response to environmental cues. However, the exact roles of such dynamic, non-covalent interactions in peptide charge transport have remained elusive. To tackle this challenge, here we report the modulation of charge transport in a series of lysine(Lys)-substituted hepta-glycine(Gly) peptide self-assembled monolayers(SAMs) on template-striped gold(Au^(TS)) bottom electrodes with eutectic gallium-indium(EGaIn) liquid metal top electrodes. We demonstrate systematic modulation of hydrogen bonding and more general electrostatic interactions by shifting the position of the charged Lys-residue and creating different protonation patterns by changing the environmental pH in the Au^(TS)/peptide//Ga Ox/EGa In junctions. The effective modulation is evidenced by current density-voltage(J-V) measurements combined with SAM characterization using ultraviolet photoelectron spectroscopy(UPS) and angle-resolved X-ray photoelectron spectroscopy(ARXPS), polarization modulation-infrared reflection-absorption spectroscopy(PM-IRRAS), and molecular dynamics(MD) simulations. Decreasing the hydrogen bonding inside the peptide SAMs and increasing the electrostatic interactions by environmental counterions amplifies the charge transport differently with Lys-position, which means that the sensitive electrical response of peptide SAMs can be tuned by the peptide sequence. Our results provide insights into the relationship between molecular design and in situ modulation of charge transport properties for the development of bionanoelectronics.
基金supported by the Fund for Creative Research Groups of National Natural Science Foundation of China (No. 51821093)the National Natural Science Foundation of China (Nos. 52175551, 52075484)(KT and DM)+2 种基金the National Key Research and Development Program (SQ2021YFE010405)(KT)Science Foundation Ireland (SFI) through awards Nos. 15/CDA/3491and 12/RC/2275_P2 (DT)computing resources at the SFI/Higher Education Authority Irish Center for High-End Computing (ICHEC)(SG and DT)
文摘Vectored non-covalent interactions—mainly hydrogen bonding and aromatic interactions—extensively contribute to(bio)-organic self-assembling processes and significantly impact the physicochemical properties of the associated superstructures.However,vectored non-covalent interaction-driven assembly occursmainly along one-dimensional(1D)or three-dimensional(3D)directions,and a two-dimensional(2D)orientation,especially that of multilayered,graphene-like assembly,has been reported less.In this present research,by introducing amino,hydroxyl,and phenyl moieties to the triazine skeleton,supramolecular layered assembly is achieved by vectored non-covalent interactions.The planar hydrogen bonding network results in high stability,with a thermal sustainability of up to about 330°C and a Young’s modulus of up to about 40 GPa.Upon introducing wrinkles by biased hydrogen bonding or aromatic interactions to disturb the planar organization,the stability attenuates.However,the intertwined aromatic interactions prompt a red edge excitation shift effect inside the assemblies,inducing broad-spectrum fluorescence covering nearly the entire visible light region(400–650 nm).We show that bionic,superhydrophobic,pillar-like arrays with contact angles of up to about 170°can be engineered by aromatic interactions using a physical vapor deposition approach,which cannot be realized through hydrogen bonding.Our findings show the feasibility of 2D assembly with engineerable properties by modulating vectored non-covalent interactions.
基金supported by projects granted by the National Natural Science Foundation of China(Nos.52171071 and 51801081)national funds through FCT of Portugal-Fundação para a Ciência e a Tecnologia,under a scientific contract of 2021.04115.CEECIND,2023.06224.CEECIND+3 种基金the projects of UIDB/00285/2020,and LA/0112/2020,MCTool21-ref.“POCI-01-0247-FEDER-045940”co-financed via FEDER and FCTFundação para a Ciência e a Tecnologia(COMPETE)The projects of UIDB/00285/2020,and LA/0112/2020The Slovenian Research Agency ARIS under the Research Core Funding Programme No.P2-0231 and the project MSCA-COFUND-5100-237/2023-9supported by the Outstanding University Young Teachers of“Qing Lan Project”of Jiangsu Province of China and the Excellent Talents of“Shenlan Project”of Jiangsu University of Science of China.
文摘The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated temperatures,has hindered the widespread use of these materials in industrial applications.This paper took this challenge to break through the above established relationship by developing novel nacrelike multilayered Mo_(2)N–SiN_(x)/Ag–SiN_(x)self-lubricant films via an radio frequency(RF)magnetron sputtering system for real applications where harsh conditions at elevated temperatures exist.The multilayered films,deposited by alternating deposition of Mo_(2)N–SiN_(x)and Ag–SiN_(x)modulation layers,exhibited three phases of face-centered cubic(fcc)Mo_(2)N,fcc Ag and SiN_(x),where SiN_(x)encapsulated the nano-crystalline Mo_(2)N and Ag phases in each layer to successfully induce a“brick and mortar”nacre-like microstructure(in the area without the coherent structure).The epitaxy growth of the Ag–SiN_(x)layers with thickness below 6 nm on the Mo_(2)N template resulted in an extraordinary increase in both the hardness and elastic modulus,which was able to prevent severe degradation of the mechanical properties caused by the addition of Ag.The room-temperature anti-friction property could be enhanced by increasing the Ag–SiN_(x)layer thickness due to the excellent lubricant nature of Ag,which acts in synergy with Mo_(2)N,while the wear rate below 4×10^(−8)mm^(3)/(N·mm)was due to the high mechanical strength.The tribological properties at 600℃also benefited from the interlocked multilayered architecture,which allowed an extreme low friction coefficient of~0.12 and a negligible wear rate(WR).This behavior was attributed to the synergism between the lubricant action of Ag and Mo_(2)N and the tribo-phase transformation from Ag_(2)Mo_(4)O_(13)to Ag_(2)MoO_(4).
基金supported by the National Natural Science Foundation of China(grant nos.22201304,22178378,and 22127812)the Science Foundation of China University of Petroleum-Beijing(grant nos.2462021QNXZ011 and 2462022YXZZ007).
文摘Industrial purification processes for ethylene from steam pyrolysis or cracking gases generally employ multiple energy-intensive steps to remove C_(2)H_(2),C_(2)H_(6),CO_(2),and C_(3) hydrocarbons.Designing multifunctional molecular separators that integrate multiple structural characteristics capable of removing several impurities simultaneously is highly desired but not yet realized.Here,we address this challenge using a custom-designed multifunctional,and industry-compatible ultramicroporous crystalline physisorbent(CALF-20)to purify C_(2)H_(4) from a seven-component cracking gas mixture(C_(2)H_(4),C_(2)H_(2),C_(2)H_(6),CO_(2),C_(3)H_(4),C_(3)H_(6),and C_(3)H8)by one-step separation with remarkable performance.Verified by breakthrough experiments,C_(2)H_(4)(>99.99%)can be recovered not only from binary C_(2)H_(6)/C_(2)H_(4)(50/50),ternary C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)(33/33/33),and quaternary C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)/CO_(2)(25/25/25/25)mixtures,but also from a typical seven-component gas cracking mixture of C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)/CO_(2)/C_(3)H_(4)/C_(3)H_(6)/C_(3)H8(0.6/62/10/0.3/0.6/26/0.5),even at the high humidity of 74%.Notably,CALF-20 can be easily produced on the kilogram scale,showing great commercial application potential.Together with its framework flexibility and appropriate pore geometry,CALF-20 exhibits a sorbent-sorbate induced-fit behavior strengthening multiple specific recognition sites for the corresponding vips,validated by single-crystal X-ray diffraction study and molecular modeling.This work is the first example of using a single physisorbent to purify C_(2)H_(4) from a seven-component cracking gas mixture and opens an avenue to address complicated hydrocarbon mixture separation challenges.
基金funded by Iran National Science Foundation(INSF)under project NO.4015025financially supported by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-SFB 1270/1,2-299150580.
文摘This review paper explores the cutting-edge advancements in hydrogel design for articular cartilage regeneration(CR).Articular cartilage(AC)defects are a common occurrence worldwide that can lead to joint breakdown at a later stage of the disease,necessitating immediate intervention to prevent progressive degeneration of cartilage.Decades of research into the biomedical applications of hydrogels have revealed their tremendous potential,particularly in soft tissue engineering,including CR.Hydrogels are highly tunable and can be designed to meet the key criteria needed for a template in CR.This paper aims to identify those criteria,including the hydrogel components,mechanical properties,biodegradability,structural design,and integration capability with the adjacent native tissue and delves into the benefits that CR can obtain through appropriate design.Stratifiedstructural hydrogels that emulate the native cartilage structure,as well as the impact of environmental stim-uli on the regeneration outcome,have also been discussed.By examining recent advances and emerging tech-niques,this paper offers valuable insights into developing effective hydrogel-based therapies for AC repair.
基金supported by financial support in part by NSFC (91961106, 51902253, 21725102)Anhui Provincial Natural Science Foundation (Grant 2108085MB46)+1 种基金Key Project of Youth Elite Support Plan in Universities of Anhui Province (Grant gxyqZD2021121)Shaanxi Provincial Natural Science Foundation (2020JQ-778)。
文摘Very recently, the local coordination environment of active sites has been found to strongly influence their performance in electrocatalytic CO_(2) reduction by tuning the intrinsic kinetics of CO_(2) activation and intermediate stabilization. It is imperative to elucidate the mechanism for such an influence towards the rational design of efficient catalysts;however, the complex interactions between the multiple factors involved in the system make it challenging to establish a clear structure–performance relationship. In this work, we chose ion-intercalated silver(I)-based coordination networks(AgCNs) with a well-defined structure as a model platform, which enables us to understand the regulation mechanism of counterions as the counterions are the only tuning factor involved in such a system. We prepared two isostructural Ag CNs with different intercalation ions or counterions of BF_(4)^(-) and ClO_(4)^(-)(named as AgCNs-BF_(4) and AgCNs-ClO_(4)) and found that the former has a more competitive CO_(2) electroreduction performance than the latter. AgCNs-BF_(4) achieves the highest Faradaic efficiency for CO_(2) to CO of 87.1% at-1.0 V(vs. RHE) with a higher partial current density, while AgCNs-ClO_(4) exhibits only 77.2% at the same applied potential.Spectroscopic characterizations and theoretical calculation reveal that the presence of BF_(4)^(-)is more favorable for stabilizing the COOH^(*) intermediate by weakening hydrogen bonds, which accounts for the superior activity of Ag CNs-BF_(4).
基金would like to thank the funding provided by the Irish Research Council through the IRC Postdoctoral Fellowship(GOIPG/2021/75).
文摘The relationships between hyaluronic acid(HA)and pathological microorganisms incite new understandings on microbial infection,tissue penetration,disease progression and lastly,potential treatments.These understandings are important for the advancement of next generation antimicrobial therapeutical strategies for the control of healthcare-associated infections.Herein,this review will focus on the interplay between HA,bacteria,fungi,and viruses.This review will also comprehensively detail and discuss the antimicrobial activity displayed by various HA molecular weights for a variety of biomedical and pharmaceutical applications,including microbiology,pharmaceutics,and tissue engineering.
文摘Graphene oxide (GO) possesses excellent mechanical strength,biocompatibility,colloidal stability,large surface area and high adsorption capability.It has driven to cancer nanotechnology to defeat cancer therapy obstacles,via integration into three-dimensional (3D) hydrogel network with biocompatible polymers as nanocomposites carrier,and controllable release of anticancer drugs.Specifically,the surface of GO affords π-π stacking and hydrophilic interactions with anticancer drugs.Additionally,modification of GO with various polymers such as natural and synthetic polymers enhances its biodegradability,drug loading,and target delivery.In this review,GO based hydrogels research accomplishments are reviewed on the aspects of crosslinking strategies,preparation methods,the model drug,polymer conjugation and modification with targeting ligands.Moreover,swelling kinetics,drug release profile and biological activity in vivo and in vitro are discussed.The biocompatibility of GO based hydrogels is also discussed from the perspective of its nano-bio interfaces.Apart from that,the clinical potential of GO based hydrogels and its major challenges are addressed in detail.Finally,this review concludes with a summary and invigorating future perspectives of GO based hydrogels for anticancer drug delivery.It is anticipated that this review can stimulate a new research gateway to facilitate the development of anticancer drug delivery by harnessing the unique properties of GO based hydrogels,such as large surface area,chemical purity,high loading capacity of drug,chemical stability,and the nature of lipophilic for cell membrane penetration.
基金the support from the Science Foundation Ireland(SFI)National Access Programme(number 444)SFI 17/CDA/4733+6 种基金the support from the special fund of Wuhan University Graduate Students overseas exchange programthe support from SFI 16/IA/4629,12/RC/2278_P2,12/RC/2302_P2the Irish Research Council under IRCLA/2017/285the funding provided by SFI under grants 12/RC/2276_P2 and 15/IA/2864the support from SFI 13/CDA/2221the support from the National Natural Science Foundation of China(Grants numbers 91850207 and 11674256)the National Key R&D Program of China(Grant number 2017YFA0205800).
文摘Second harmonic generation and sum frequency generation(SHG and SFG)provide effective means to realize coherent light at desired frequencies when lasing is not easily achievable.They have found applications from sensing to quantum optics and are of particular interest for integrated photonics at communication wavelengths.Decreasing the footprints of nonlinear components while maintaining their high up-conversion efficiency remains a challenge in the miniaturization of integrated photonics.Here we explore lithographically defined AlGaInP nano(micro)structures/Al_(2)O_(3)/Ag as a versatile platform to achieve efficient SHG/SFG in both waveguide and resonant cavity configurations in both narrow-and broadband infrared(IR)wavelength regimes(1300-1600 nm).The effective excitation of highly confined hybrid plasmonic modes at fundamental wavelengths allows efficient SHG/SFG to be achieved in a waveguide of a cross-section of 113 nm×250 nm,with a mode area on the deep subwavelength scale(λ2/135)at fundamental wavelengths.Remarkably,we demonstrate direct visualization of SHG/SFG phase-matching evolution in the waveguides.This together with mode analysis highlights the origin of the improved SHG/SFG efficiency.We also demonstrate strongly enhanced SFG with a broadband IR source by exploiting multiple coherent SFG processes on 1μm diameter AlGaInP disks/Al_(2)O_(3)/Ag with a conversion efficiency of 14.8%MW^(−1) which is five times the SHG value using the narrowband IR source.In both configurations,the hybrid plasmonic structures exhibit>1000 enhancement in the nonlinear conversion efficiency compared to their photonic counterparts.Our results manifest the potential of developing such nanoscale hybrid plasmonic devices for state-of-the-art on-chip nonlinear optics applications.
文摘Ferroelectricity in biological system has been anticipated both theoretically and experimentally over the past few decades.Claims of ferroelectricity in biological systems have given rise to confusion and methodological controversy.Over the years,a“loop”of induced polarization in response to a varying applied electrical field and a consequent polarization reversal has prompted many researchers to claim ferroelectricity in biological structures and their building blocks.Other observers were skeptical about the methodology adopted in generating the data and questioned the validity of the claimed ferroelectricity as such,“loop”can also be obtained from linear capacitors.In a paper with somewhat tongue-in-cheek title,Jim Scott showed that ordinary banana peels could exhibit closed loops of electrical charge which closely resemble and thus could be misinterpreted as ferroelectric hysteresis loops in barium sodium niobate,BNN paraphrasing it as“banana”.In this paper,we critically review ferroelectricity in biological system and argue that knowing the molecular and crystalline structure of biological building blocks and experimenting on such building blocks may be the way forward in revealing the“true”nature of ferroelectricity in biological systems.
基金supported by Tianjin Natural Science Foundation(20JCJQJC00170)National Natural Science Foundation of China(22001131 and 22175099)+2 种基金Frontiers Science Center for New Organic Matter of Nankai University(63181206)111 Project(B12015)Postdoctoral Science Foundation of China(2019M660974).
文摘Solid polymer electrolytes have demonstrated high promise to solve the safety problems caused by conventional liquid electrolytes in lithium ion batteries.However,the inherent flammability of most polymer electrolyte materials remains unresolved,hence hindering their further industrial application.Addressing this challenge,we designed and constructed a thermal-responsive imide-linked covalent organic framework(COF)bearing ortho-positioned hydroxy groups as precursors,which can conduct a thermal rearrangement to transform into a highly crystalline and robust benzoxazole-linked COF upon heating.Benefiting from the release of carbon dioxide through thermal rearrangement reaction,this COF platform exhibited excellent flame retardant properties.By contrast,classic COFs(e.g.,boronate ester,imine,olefin,imide linked)were all flammable.Moreover,incorpo-rating polyethylene glycol and Li salt into the COF channels can produce solid polymer electrolytes with outstanding flame retardancy,high ionic conductivity(6.42×10^(-4) S cm^(-1))and a high lithium-ion transference number of 0.95.This thermal rearrangement strategy not only opens a new route for the fabrication of ultrastable COFs,but also provides promising perspectives to designing flame-retardant materials for energy-related applications.
基金from FWO-Vlaanderen(12K8216N)Z.H.ack no wledges the Research Foundation Flanders(research projects 17006602 and G0F0920N)+1 种基金Ghent University(GOA no.01G01513)for funding.AJ.H acknowledges the ERC and NWO-TTW.S.Bisschop is acknowledged for SEM imaging of the platelet layers and K.De Nolf for help with the CdSe QD/platelet synthesis respectively.This project has received fun ding from the European Research Council(ERC)under the European Union's Horizon 2020 research and innovation program(grant agreement no.714876 PHOCONA).
文摘2D materials are considered for applications that require strong light-matter interaction because of the apparently giant oscillator strength of the exciton transitions in the absorbance spectrum.Nevertheless,the effective oscillator strengths of these transitions have bee n scarcely reported,nor is there a con sistent interpretati on of the obtained values.Here,we analyse the transition dipole moment and the ensuing oscillator strength of the exciton transition in 2D CdSe nanoplatelets by means of the optically induced Stark effect(OSE).Intriguingly,we find that the exciton absorption line reacts to a high intensity optical field as a transition with an oscillator strength FStark that is 50 times smaller than expected based on the linear absorption coefficient.We propose that the pronounced exciton absorption line should be seen as the sum of multiple,low oscillator strength transitions,rather than a single high oscillator strength one,a feat we assign to strong exciton center-of-mass localization.Within the quantum mechanical description of excitons,this 50-fold difference between both oscillator strengths corresponds to the ratio between the cohere nee area of the exciton's center of mass and the total area,which yields a coherence area of a mere 6.1 nm2.Since we find that the coherence area in creases with reducing temperature,we conclude that thermal effects,related to lattice vibrations,contribute to exciton localization.In further support of this localization model,we show that FStark is in dependent of the n anoplatelet area,correctly predicts the radiative lifetime,and lines up for strongly confined quantum dot systems.
