Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is oft...Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is often influenced by electrostatic interactions.In this letter,we report a capacitive excitation PFM(ce-PFM)to minimize the electrostatic interactions.The effectiveness of ce-PFM in minimizing electrostatic interactions is demonstrated by comparing the piezoresponse and the effective piezoelectric coefficient measured by ce-PFM and conventional PFM.The effectiveness is further confirmed through the ferroelectric domain pattern imaged via ce-PFM and conventional PFM in vertical modes,with the corresponding domain contrast obtained by ce-PFM is sharper than conventional PFM.These results demonstrate ce-PFM as an effective tool to minimize the interference from electrostatic interactions and to image ferroelectric domain pattern,and it can be easily implemented in conventional atomic force microscope(AFM)setup to probe true piezoelectricity at the nanoscale.展开更多
In this work,a new type of hydrophobic stationary phase that provide electrostatic interactions with analytes was developed by bondingβ-phenylethylamine as a functional ligand to silica.This stationary phase can sepa...In this work,a new type of hydrophobic stationary phase that provide electrostatic interactions with analytes was developed by bondingβ-phenylethylamine as a functional ligand to silica.This stationary phase can separate proteins with similar hydrophobicity that traditional hydrophobic resins cannot.Hen egg white was separated to examine the selectivity.The results show that the introduced electrostatic interactions are an important factor for the resolution enhancement and the new resin could have important applications in separation and purification of biological macromolecules.展开更多
Polystyrene nanoparticles with negative charges(n-PSs) were synthesized using styrene(St) and sodium styrene sulfonate(NaSS) as initial materials by surfactant-free emulsion polymerization. Subsequently, a hybri...Polystyrene nanoparticles with negative charges(n-PSs) were synthesized using styrene(St) and sodium styrene sulfonate(NaSS) as initial materials by surfactant-free emulsion polymerization. Subsequently, a hybrid hydrogel was prepared using acrylamide(AAm) and methacryloyloxyethyltrimethyl ammonium chloride(DMC) as co-monomers with N,N'-methylenebisacrylmnide(MBA) as a chemical crosslinker and n-PSs as a physical electrostatic interaction agent. The resulting hybrid hydrogels exhibited excellent tensile strength and elongation at break. The tensile stress of hybrid hydrogels was seven times greater than that ofhydrogels without n-PSs. The elongation at break of hydrogels reached 700%, which was much higher compared to those of the hydrogels without n-PSs. Furthermore, swelling measurements of the hydrogels indicate that there is an overshoot in the swelling process and the extent of overshoot decreases with the increasing n-PSs. Therefore, the work presented here provides a method for improving the mechanical properties of hydrogels via the introduction of polymeric nanoparticles.展开更多
Until now, nerve conduction has been described on the basis of equivalent circuit model and cable theory, both of which supposed closed electric circuits spreading inside and outside the axoplasm. With these conventio...Until now, nerve conduction has been described on the basis of equivalent circuit model and cable theory, both of which supposed closed electric circuits spreading inside and outside the axoplasm. With these conventional models, we can simulate the propagating pattern of action potential along the axonal membrane based on Ohm's law and Kirchhoff's law. However, we could not fully explain the different conductive patterns in unmyelinated and myelinated nerves with these theories. Also, whether we can really suppose closed electrical circuits in the actual site of the nerves or not has not been fully discussed yet. In this report, a recently introduced new theoretical model of nerve conduction based on electrostatic molecular interactions within the axoplasm will be reviewed. With this new approach, we can explain the different conductive patterns in unmyelinated and myelinated nerves. This new mathematical conductive model based on electrostatic compressional wave in the intracellular fluid may also be able to explain the signal integration in the neuronal cell body and the back-propagation mechanism from the axons to the dendrites. With this new mathematical nerve conduction model based on electrostatic molecular interactions within the intracellular fluid, we may be able to achieve an integrated explanation for the physiological phenomena taking place in the nervous system.展开更多
The light weight,good bending resistance and low production cost make flexible perovskite solar cells(PSCs)good candidates in wearable electronics,portable charger,remote power,and flying objects.High power conversion...The light weight,good bending resistance and low production cost make flexible perovskite solar cells(PSCs)good candidates in wearable electronics,portable charger,remote power,and flying objects.High power conversion efficiency(PCE)plays a crucial role on obtaining the high mass specific power of flexible devices.However,the performance for flexible PSCs is still having a large room to be improved.Here,we added the 2-amino-5-cyanopyridine(ACP)molecule with a polar electron density distribution in the perovskite precursor solution to improve the performance of flexible PSCs.The cyano groups with electron-withdrawing ability are expected to passivate positively charged point defects,while amines with electron donating ability are expected to passivate negatively charged point defects in perovskite films.Thanks to the effective passivation of defects at the grain boundary and surface of perovskite films,the PCE of flexible PSCs is obviously increased from 16.9%to 18.0%.These results provide a universal approach to improve performance of flexible PSCs by healing the defects in perovskite films through electrostatic interactions.展开更多
Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Her...Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Herein,the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed.The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath,inducing stable solid electrolyte interphase with fast Li+transport kinetics on the anode.This asdesigned electrolyte exhibits excellent compatibility with Li metal anode(a Li deposition/stripping Coulombic efficiency of 99.3%)and high-voltage LiCoO_(2) cathode.Consequently,the 50μm-thin Li||high-loading LiCoO_(2) cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V,lean electrolyte,and wide temperature range(-20 to 60℃).This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for highperformance Li metal batteries.展开更多
The electrostatic interaction of a charged spherical particle in the vicinity of an orifice plane has been investigated in this paper. The particle can creep along the axis of the orifice and is immersed in a bulk ele...The electrostatic interaction of a charged spherical particle in the vicinity of an orifice plane has been investigated in this paper. The particle can creep along the axis of the orifice and is immersed in a bulk electrolyte. By solving the Poisson-Boltzmann problem, we have obtained the effective electrostatic interaction for several values of reduced orifice radius h, including the cases of h ~ 1, h = i and h 〈 1. Two kinds of boundary conditions of the orifice plane are considered. One is the constant potential model corresponding to a conducting plane, the other is the constant charge model. In the constant potential model, there is an electrostatic attraction between the particle and the orifice plane when they get close to each other, while there is a pure electrostatic repulsion in the constant charge model. The interactions in both boundary models are sensitive to the parameters of the reduced orifice radius, the reduced particle-rifice distance, surface charge densities of the particle and orifice plane, and the reduced Debye screen constant corresponding to the salt-ion concentration and ion valence.展开更多
Electrostatic interaction conductive hybrids were prepared in water/ethanol solution by the sol-gel process from inorganic sol containing carboxyl group and water-borne conductive polyaniline (cPANI). The electrosta...Electrostatic interaction conductive hybrids were prepared in water/ethanol solution by the sol-gel process from inorganic sol containing carboxyl group and water-borne conductive polyaniline (cPANI). The electrostatic interaction hybrids film displayed 1-2 orders of magnitude higher electrical conductivity in comparison with common hybrids film, showing remarkable conductivity stability against water soaking. Most strikingly, it displayed ideal electrochemical activity even in a solution with pH = 14, which enlarged the conducting polyaniline application window to strong alkaline media.展开更多
We present the solutions of the interaction energy for a colloid system with a charged rod-like macromolecule immersed in a bulk electrolyte and moving along the axis of a circular orifice or disk (orifice/disk). Th...We present the solutions of the interaction energy for a colloid system with a charged rod-like macromolecule immersed in a bulk electrolyte and moving along the axis of a circular orifice or disk (orifice/disk). The calculation requires a numerical computation of the surface charge profiles, which result from a constant surface potential on the macromolecule and the orifice/disk. In the calculation, remarkable divergences of the surface charge emerge on the edges of the macromolecule and the orifice/disk, which are well-known edge effects. The anisotropic distribution of the surface charge (effective dipole) results in an attraction between these two charged objects. This attraction is enhanced with the increase of the screening length of the system for both the orifice and the disk systems. However, the sizes of the orifice and the disk reduce to different effects on the interaction energy.展开更多
Soy protein isolate(SPI)is a commercial protein with balanced amino acids,while the poor solubility impedes its use in traditional foods.To overcome the problem,the complex coacervation of SPI/Flammulina velutipes pol...Soy protein isolate(SPI)is a commercial protein with balanced amino acids,while the poor solubility impedes its use in traditional foods.To overcome the problem,the complex coacervation of SPI/Flammulina velutipes polysaccharide(FVP)were investigated.Initial results revealed that the suitable amounts of FVP contributed to reducing the turbidity of SPI solution.Under electrostatic interaction,the formation of SPI/FVP coacervates were spontaneous and went through a nucleation and growth process.Low salt concentration(C_(NaCl)=10,50 mmol/L)led to an increase in the critical pH values(pHc,pHφ1)while the critical pH values decreased when C_(NaCl)≥100 mmol/L.The concentration of NaCl ions increased the content ofα-helix.With the increase of FVP,the critical pH values decreased and the content ofβ-sheet increased through electrostatic interaction.At SPI/FVP ratio of 10:1 and 15:1,the complex coacervation of SPI/FVP were saturated,and the coacervates had the same storage modulus value.SPI/FVP coacervates exhibited solid-like properties and presented the strongest storage modulus at C_(NaCl)=50 mmol/L.The optimal pH,SPI/FVP ratio and NaCl concentration of complex coacervation were collected,and the coacervates demonstrated a valuable application potential to protect and deliver bioactives and food ingredients.展开更多
Excessive turbidity in water is aesthetically unappealing and severely malfunctions the photosynthesis process of aquatic ecosystems. This study aimed to evaluate the effectiveness of a nanocomposite adsorbent made of...Excessive turbidity in water is aesthetically unappealing and severely malfunctions the photosynthesis process of aquatic ecosystems. This study aimed to evaluate the effectiveness of a nanocomposite adsorbent made of graphene oxide-keratin-chitosan for removing turbidity from tannery influent. The nanocomposite was fabricated with simple solution casting methods. Material dispersibility, bonding between composite materials (amide linkage), and the surface morphology of the nanocomposite were analyzed with the ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. At pH of 6, 2 g/L of adsorbent and a 25-min contact time resulted in about 88% of turbidity elimination. After the adsorption process, the total suspended solids, total dissolved solids, salinity, biochemical oxygen demand, and chemical oxygen demand of the tannery wastewater were reduced by 55%, 29%, 12%, 58%, and 75%, respectively. The optimum dosage of the nanocomposite with the maximum turbidity removal capacity was 12.62 mg/g. According the adsorption kinetic and isotherm models, the graphene oxide-keratin-chitosan nanocomposite played a key role in the turbidity removal process with chemisorption and electrostatic multilayer adsorption. This study provided methodological and mechanistic insights into the procedures of investigating the removal of turbidity from tannery wastewater with a novel composite material.展开更多
The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate(WPI)and coated by chitosan(CHI),carboxymethyl konjac glucomannan...The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate(WPI)and coated by chitosan(CHI),carboxymethyl konjac glucomannan(CMKGM),or their combination through layer-by-layer assembly was investigated.Generally,the multilayered emulsions were destabilized in high Na Cl concentrations or medium p H that could interrupt the electrostatic interaction between the three polyelectrolytes or deprotonate CHI,indicating that electrostatic interaction played an important role in the stability of emulsions.Compared with the primary emulsion that was solely stabilized by WPI,extra coating with CHI and CMKGM generally increased the stability of the emulsion against repeated freezing-thawing,improved the retention of curcumin against heating,UV irradiation,and long-term storage,and the effects were more remarkable in the tertiary emulsion with CMKGM locating in the outmost layer.Since CMKGM has shown the colon-targeted delivery potency,the multilayered emulsions assembled by layer-by-layer deposition,especially the tertiary emulsion,could be used as an effective carrier for the targeted delivery of curcumin.展开更多
Refractory dissolved organic matter (DOM) from landfill leachate treatment plant was with high dissolved organic carbon (DOC) content. An aminated polymeric adsorbent NDA-8 with tertiary amino groups and sufficien...Refractory dissolved organic matter (DOM) from landfill leachate treatment plant was with high dissolved organic carbon (DOC) content. An aminated polymeric adsorbent NDA-8 with tertiary amino groups and sufficient mesopore was synthesized, which exhibited high adsorption capacity to the DOM (raw water after coagulation). Resin NDA-8 performed better in the uptake of the DOM than resin DAX-8 and A100. Electrostatic attraction was considered as the decisive interaction between the adsorbent and adsorbate. Special attention was paid to the correlation between porous structure and adsorption capacity. The mesopore of NDA-8 played a crucial role during uptake of the DOM. In general, resin in chloride form performed a higher removal rate of DOC. According to the colunm adsorption test, total adsorption capacity of NDA-8 was calculated to 52.28 mg DOC/mL wet resin. 0.2 mol/L sodium hydroxide solution could regenerate the adsorbent efficiently.展开更多
Piezoelectric poly(vinylidene fluoride)(PVDF)has received considerable attention due to its ability of interconverting mechanical into electric energies and potential applications in wearable electronics.To achieve pi...Piezoelectric poly(vinylidene fluoride)(PVDF)has received considerable attention due to its ability of interconverting mechanical into electric energies and potential applications in wearable electronics.To achieve piezoelectricity,it is important to simultaneously control the formation of polar phases,crystallinity,and dipole alignments in PVDF-based films.Here we demonstrate that piezoelectricity can be obtained by directly hot-pressing PVDF films sandwiched between chitosan or cellulose films.The electrostatic interactions between PVDF and chitosan or cellulose enabled an exceptional high content of polar phases(β-andγ-phases)up to 90%and a measured piezoelectric charge coefficient d_(33)of up to-30 pC/N.This study provides a simple and low-cost approach for obtaining piezoelectric PVDF films used for sensors,actuators,and energy harvesters.展开更多
Background:Retinol dehydrogenase 8(RDH8)is a 312-amino acid(aa)protein involved in the visual cycle.Bound to the outer segment disk membranes of photoreceptors,it reduces all-trans-retinal to all-trans-retinol1 as one...Background:Retinol dehydrogenase 8(RDH8)is a 312-amino acid(aa)protein involved in the visual cycle.Bound to the outer segment disk membranes of photoreceptors,it reduces all-trans-retinal to all-trans-retinol1 as one of the rate-limiting steps of the visual cycle2.RDH8 is a member of the short-chain dehydrogenase/reductase family.Its C-terminal segment allows its membrane-anchoring through the postulated presence of an amphipathicα-helix and of 1 to 3 acyl groups at positions 299,302 and 3043.The secondary structure and membrane binding characteristics of RDH8 and its C-terminal segment have not yet been described.Methods:To evaluate the membrane binding of RDH8,the full-length protein(aa 1-312),a truncated form(aa 1-296),its C-terminal segment(aa 281-312 and 297-312)as well as different additional variants of this segment were used.The truncated protein binds membranes less efficiently than the full-length form.Thus,the C-terminal segment of RDH8 is essential for the binding and has thus been further examined.The intrinsic fluorescence of tryptophan residues at positions 289 and 310 of the wild-type C-terminal segment of RDH8 and the mutants W289F,W310F and W310R have thus been used to determine their extent of binding to lipid vesicles and to monitor their local environment.Unilamellar lipid vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)or a mixture of POPC and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(POPS)were used to mimic the phospholipid content of the outer segment disk membranes of photoreceptors.Results:An increase in fluorescence intensity and in fluorescence lifetime is observed upon increasing the concentration of lipid vesicles.These data allowed calculating values of partition coefficient of the C-terminal segment of RDH8 varying between Kp=1.1 E6 to 1.7 E6.It is noteworthy that the observation of a more intense shift to lower wavelengths upon membrane binding of the mutant W310R and W310F indicates a deeper incorporation of the remaining tryptophan residue at position 289 into the lipid bilayer.The secondary structure of the C-terminal segment of RDH8 observed by circular dichroism and infrared spectroscopy shows a superposition ofα-helical,β-turn and unordered structures.Conclusions:The peptides derived from the C-terminal segment of RDH8 show a strong binding to lipid vesicles.These strength of binding is independent of the type of lipid and the presence of a mutation.展开更多
The development of polymer-based solid-state batteries is severely limited by the low ionic conductivity of solid polymer electrolyte and the instable interface between polymer electrolyte and Li-metal anode.In this w...The development of polymer-based solid-state batteries is severely limited by the low ionic conductivity of solid polymer electrolyte and the instable interface between polymer electrolyte and Li-metal anode.In this work,lithium iodide(LiI)as a bifunctional additive was introduced into the poly(ethylene oxide)(PEO)-based electrolyte to improve the ionic conductivity and to construct a stable interphase at the Li/PEO interface.I-anions offer a strong electrostatic interaction with hydrogen atoms on PEO chains(HPEO)and forming massive I–H bonds that cross-link PEO chains,decrease crystallinity of PEO,and thus improve Li~+interchain transport.In addition,LiI participates in the formation of an inorganic-rich interphase layer,which decreases the energy barrier of Li+transport across the interface and thus inhibits the growth of lithium dendrites.As a result,the composite PEO electrolyte with 2 wt%LiI(PEO-2 LiI)presents a very high ionic conductivity of 2.1×10^(-4) S cm-1 and a critical current density of 2.0 m A cm^(-2) at 45°C.Li symmetric cell with this PEO-2 LiI electrolyte exhibits a long-term cyclability over 600 h at 0.2 m A cm^(-2).Furthermore,solid-state LiFePO_(4) and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) batteries with the PEO-2 LiI electrolyte show an impressive electrochemical performance with outstanding cycling stability and rate capability at 45°C.展开更多
Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zw...Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zwitterionic materials,nucleic acids,proteins,biomembranes and etc.,where the electrostatic interactions are of special significance.Several methods have been available for treating the electrostatic interactions in explicit and implicit solvent models.Accurate and efficient treatment of such interactions has therefore always been one of the most challenging issues in classical molecular dynamics simulations due to their inhomogeneity and long-range characteristics.Currently,two major challenges remain in the application field of electrostatic interactions in molecular simulations;(i)improving the representation of electrostatic interactions while reducing the computational costs in molecular simulations;(ii)revealing the role of electrostatic interactions in regulating the specific properties of complex fluids.In this review,the calculation methods of electrostatic interactions,including basic principles,applicable conditions,advantages and disadvantages are summarized and compared.Subsequently,the specific role of electrostatic interactions in governing the properties and behaviors of different complex fluids is emphasized and explained.Finally,challenges and perspective on the computational study of charged systems are given.展开更多
Adsorption of poly(L-lysine) on surface-attached poly(methacrylic acid) monolayers formed through in situ free radical polymerization was investigated. A strong "template effect" was observed for the adsorption ...Adsorption of poly(L-lysine) on surface-attached poly(methacrylic acid) monolayers formed through in situ free radical polymerization was investigated. A strong "template effect" was observed for the adsorption of poly(L-lysine) on poly(methacrylic acid) layers, which were perpendicularly grown from the surface of substrates. The adsorbed amount of poly(amino acid) increases linearly with the increase in initial layer thickness of poly(methacrylic acid) monolayers. In addition, the adsorbed poly(amino acid) is relatively stable in medium concentration of salt solution but can be completely released from the brush in high salt concentration.展开更多
Stabilization of proteins in delivery devices and design of appropriate protein carriers are major research issues due to the extreme sensitivity of proteins.Previously,negatively charged nanoparticles,consisting of p...Stabilization of proteins in delivery devices and design of appropriate protein carriers are major research issues due to the extreme sensitivity of proteins.Previously,negatively charged nanoparticles,consisting of poly(lactic-co-glycolic acid)(PLGA)and poly(styrene-co-4–styrene-sulfonate)(PSS),showed considerably high loading capacity for positively charged model protein lysozyme depending on the surface charge density of nanoparticles.展开更多
基金We acknowledge the National Key Research and Development Program of China(Grant 2016YFA0201001)the National Natural Science Foundation of China(Grants 11372268,11627801,and 1472236)+2 种基金Unite State National Science Foundation(Grant CBET-1435968)the Leading Talents Program of Guangdong Province(Grant 2016LJ06C372)Shenzhen Science and Technology Innovation Committee(Grant KQJSCX20170331162214306).
文摘Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is often influenced by electrostatic interactions.In this letter,we report a capacitive excitation PFM(ce-PFM)to minimize the electrostatic interactions.The effectiveness of ce-PFM in minimizing electrostatic interactions is demonstrated by comparing the piezoresponse and the effective piezoelectric coefficient measured by ce-PFM and conventional PFM.The effectiveness is further confirmed through the ferroelectric domain pattern imaged via ce-PFM and conventional PFM in vertical modes,with the corresponding domain contrast obtained by ce-PFM is sharper than conventional PFM.These results demonstrate ce-PFM as an effective tool to minimize the interference from electrostatic interactions and to image ferroelectric domain pattern,and it can be easily implemented in conventional atomic force microscope(AFM)setup to probe true piezoelectricity at the nanoscale.
基金supported by the National Natural Science Foundation in China(No.21006077)the Foundation of Northwest University(No.09NW14)
文摘In this work,a new type of hydrophobic stationary phase that provide electrostatic interactions with analytes was developed by bondingβ-phenylethylamine as a functional ligand to silica.This stationary phase can separate proteins with similar hydrophobicity that traditional hydrophobic resins cannot.Hen egg white was separated to examine the selectivity.The results show that the introduced electrostatic interactions are an important factor for the resolution enhancement and the new resin could have important applications in separation and purification of biological macromolecules.
基金Supported by the National Natural Science Foundation of China(No. 51173020).
文摘Polystyrene nanoparticles with negative charges(n-PSs) were synthesized using styrene(St) and sodium styrene sulfonate(NaSS) as initial materials by surfactant-free emulsion polymerization. Subsequently, a hybrid hydrogel was prepared using acrylamide(AAm) and methacryloyloxyethyltrimethyl ammonium chloride(DMC) as co-monomers with N,N'-methylenebisacrylmnide(MBA) as a chemical crosslinker and n-PSs as a physical electrostatic interaction agent. The resulting hybrid hydrogels exhibited excellent tensile strength and elongation at break. The tensile stress of hybrid hydrogels was seven times greater than that ofhydrogels without n-PSs. The elongation at break of hydrogels reached 700%, which was much higher compared to those of the hydrogels without n-PSs. Furthermore, swelling measurements of the hydrogels indicate that there is an overshoot in the swelling process and the extent of overshoot decreases with the increasing n-PSs. Therefore, the work presented here provides a method for improving the mechanical properties of hydrogels via the introduction of polymeric nanoparticles.
文摘Until now, nerve conduction has been described on the basis of equivalent circuit model and cable theory, both of which supposed closed electric circuits spreading inside and outside the axoplasm. With these conventional models, we can simulate the propagating pattern of action potential along the axonal membrane based on Ohm's law and Kirchhoff's law. However, we could not fully explain the different conductive patterns in unmyelinated and myelinated nerves with these theories. Also, whether we can really suppose closed electrical circuits in the actual site of the nerves or not has not been fully discussed yet. In this report, a recently introduced new theoretical model of nerve conduction based on electrostatic molecular interactions within the axoplasm will be reviewed. With this new approach, we can explain the different conductive patterns in unmyelinated and myelinated nerves. This new mathematical conductive model based on electrostatic compressional wave in the intracellular fluid may also be able to explain the signal integration in the neuronal cell body and the back-propagation mechanism from the axons to the dendrites. With this new mathematical nerve conduction model based on electrostatic molecular interactions within the intracellular fluid, we may be able to achieve an integrated explanation for the physiological phenomena taking place in the nervous system.
基金financial support from the National Natural Science Foundation of China(No.NSFC21773218)。
文摘The light weight,good bending resistance and low production cost make flexible perovskite solar cells(PSCs)good candidates in wearable electronics,portable charger,remote power,and flying objects.High power conversion efficiency(PCE)plays a crucial role on obtaining the high mass specific power of flexible devices.However,the performance for flexible PSCs is still having a large room to be improved.Here,we added the 2-amino-5-cyanopyridine(ACP)molecule with a polar electron density distribution in the perovskite precursor solution to improve the performance of flexible PSCs.The cyano groups with electron-withdrawing ability are expected to passivate positively charged point defects,while amines with electron donating ability are expected to passivate negatively charged point defects in perovskite films.Thanks to the effective passivation of defects at the grain boundary and surface of perovskite films,the PCE of flexible PSCs is obviously increased from 16.9%to 18.0%.These results provide a universal approach to improve performance of flexible PSCs by healing the defects in perovskite films through electrostatic interactions.
基金supported by National Nature Science Foundation of China(No.51872157 and No.52072208)National Key R&D Program of China 2021YFA1202802Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01N111)。
文摘Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Herein,the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed.The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath,inducing stable solid electrolyte interphase with fast Li+transport kinetics on the anode.This asdesigned electrolyte exhibits excellent compatibility with Li metal anode(a Li deposition/stripping Coulombic efficiency of 99.3%)and high-voltage LiCoO_(2) cathode.Consequently,the 50μm-thin Li||high-loading LiCoO_(2) cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V,lean electrolyte,and wide temperature range(-20 to 60℃).This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for highperformance Li metal batteries.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10805029 and 10947175)the Education Department of Natural Science Foundation of Zhejiang province of China (Grant No. Y200803420)+1 种基金the Science Foundation of Ningbo University (Grant No. xkl09057)sponsored by K.C.Wong Magna Fund in Ningbo University of China
文摘The electrostatic interaction of a charged spherical particle in the vicinity of an orifice plane has been investigated in this paper. The particle can creep along the axis of the orifice and is immersed in a bulk electrolyte. By solving the Poisson-Boltzmann problem, we have obtained the effective electrostatic interaction for several values of reduced orifice radius h, including the cases of h ~ 1, h = i and h 〈 1. Two kinds of boundary conditions of the orifice plane are considered. One is the constant potential model corresponding to a conducting plane, the other is the constant charge model. In the constant potential model, there is an electrostatic attraction between the particle and the orifice plane when they get close to each other, while there is a pure electrostatic repulsion in the constant charge model. The interactions in both boundary models are sensitive to the parameters of the reduced orifice radius, the reduced particle-rifice distance, surface charge densities of the particle and orifice plane, and the reduced Debye screen constant corresponding to the salt-ion concentration and ion valence.
基金This work was financially supported by the National Science Foundation of China (No. 20225414).
文摘Electrostatic interaction conductive hybrids were prepared in water/ethanol solution by the sol-gel process from inorganic sol containing carboxyl group and water-borne conductive polyaniline (cPANI). The electrostatic interaction hybrids film displayed 1-2 orders of magnitude higher electrical conductivity in comparison with common hybrids film, showing remarkable conductivity stability against water soaking. Most strikingly, it displayed ideal electrochemical activity even in a solution with pH = 14, which enlarged the conducting polyaniline application window to strong alkaline media.
基金Project supported by the Scientific Research Fund of the Education Department of Zhejiang Province of China (Grant No.Y200803420)the National Natural Science Foundation of China (Grant No.10947175)+1 种基金the Natural Science Foundation of Ningbo,China (Grand No.2010A610089)K.C.Wong Magna Fund in Ningbo University of China
文摘We present the solutions of the interaction energy for a colloid system with a charged rod-like macromolecule immersed in a bulk electrolyte and moving along the axis of a circular orifice or disk (orifice/disk). The calculation requires a numerical computation of the surface charge profiles, which result from a constant surface potential on the macromolecule and the orifice/disk. In the calculation, remarkable divergences of the surface charge emerge on the edges of the macromolecule and the orifice/disk, which are well-known edge effects. The anisotropic distribution of the surface charge (effective dipole) results in an attraction between these two charged objects. This attraction is enhanced with the increase of the screening length of the system for both the orifice and the disk systems. However, the sizes of the orifice and the disk reduce to different effects on the interaction energy.
基金supported by the National Key R&D Program of China (2017YFD0400205)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX19_1402)
文摘Soy protein isolate(SPI)is a commercial protein with balanced amino acids,while the poor solubility impedes its use in traditional foods.To overcome the problem,the complex coacervation of SPI/Flammulina velutipes polysaccharide(FVP)were investigated.Initial results revealed that the suitable amounts of FVP contributed to reducing the turbidity of SPI solution.Under electrostatic interaction,the formation of SPI/FVP coacervates were spontaneous and went through a nucleation and growth process.Low salt concentration(C_(NaCl)=10,50 mmol/L)led to an increase in the critical pH values(pHc,pHφ1)while the critical pH values decreased when C_(NaCl)≥100 mmol/L.The concentration of NaCl ions increased the content ofα-helix.With the increase of FVP,the critical pH values decreased and the content ofβ-sheet increased through electrostatic interaction.At SPI/FVP ratio of 10:1 and 15:1,the complex coacervation of SPI/FVP were saturated,and the coacervates had the same storage modulus value.SPI/FVP coacervates exhibited solid-like properties and presented the strongest storage modulus at C_(NaCl)=50 mmol/L.The optimal pH,SPI/FVP ratio and NaCl concentration of complex coacervation were collected,and the coacervates demonstrated a valuable application potential to protect and deliver bioactives and food ingredients.
基金supported by the Fund of Research and Extension(R&E)of Khulna University of Engineering&Technology in Bangladesh(Grant No.KUET 11).
文摘Excessive turbidity in water is aesthetically unappealing and severely malfunctions the photosynthesis process of aquatic ecosystems. This study aimed to evaluate the effectiveness of a nanocomposite adsorbent made of graphene oxide-keratin-chitosan for removing turbidity from tannery influent. The nanocomposite was fabricated with simple solution casting methods. Material dispersibility, bonding between composite materials (amide linkage), and the surface morphology of the nanocomposite were analyzed with the ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. At pH of 6, 2 g/L of adsorbent and a 25-min contact time resulted in about 88% of turbidity elimination. After the adsorption process, the total suspended solids, total dissolved solids, salinity, biochemical oxygen demand, and chemical oxygen demand of the tannery wastewater were reduced by 55%, 29%, 12%, 58%, and 75%, respectively. The optimum dosage of the nanocomposite with the maximum turbidity removal capacity was 12.62 mg/g. According the adsorption kinetic and isotherm models, the graphene oxide-keratin-chitosan nanocomposite played a key role in the turbidity removal process with chemisorption and electrostatic multilayer adsorption. This study provided methodological and mechanistic insights into the procedures of investigating the removal of turbidity from tannery wastewater with a novel composite material.
基金financial support from the Natural Science Foundation of Shandong Province(ZR2015CM037)the National Science Foundation of China(31571890)。
文摘The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate(WPI)and coated by chitosan(CHI),carboxymethyl konjac glucomannan(CMKGM),or their combination through layer-by-layer assembly was investigated.Generally,the multilayered emulsions were destabilized in high Na Cl concentrations or medium p H that could interrupt the electrostatic interaction between the three polyelectrolytes or deprotonate CHI,indicating that electrostatic interaction played an important role in the stability of emulsions.Compared with the primary emulsion that was solely stabilized by WPI,extra coating with CHI and CMKGM generally increased the stability of the emulsion against repeated freezing-thawing,improved the retention of curcumin against heating,UV irradiation,and long-term storage,and the effects were more remarkable in the tertiary emulsion with CMKGM locating in the outmost layer.Since CMKGM has shown the colon-targeted delivery potency,the multilayered emulsions assembled by layer-by-layer deposition,especially the tertiary emulsion,could be used as an effective carrier for the targeted delivery of curcumin.
基金supported by the Hi-Tech Re-search and Development Program (863) of China (No.2006AA06Z283)the National Natural Science Foundation of China (No. 50778088)the Sino-Germany Scientific and Technical Cooperation Project of Jiangsu Province (No.BZ2007020)
文摘Refractory dissolved organic matter (DOM) from landfill leachate treatment plant was with high dissolved organic carbon (DOC) content. An aminated polymeric adsorbent NDA-8 with tertiary amino groups and sufficient mesopore was synthesized, which exhibited high adsorption capacity to the DOM (raw water after coagulation). Resin NDA-8 performed better in the uptake of the DOM than resin DAX-8 and A100. Electrostatic attraction was considered as the decisive interaction between the adsorbent and adsorbate. Special attention was paid to the correlation between porous structure and adsorption capacity. The mesopore of NDA-8 played a crucial role during uptake of the DOM. In general, resin in chloride form performed a higher removal rate of DOC. According to the colunm adsorption test, total adsorption capacity of NDA-8 was calculated to 52.28 mg DOC/mL wet resin. 0.2 mol/L sodium hydroxide solution could regenerate the adsorbent efficiently.
基金financially supported by the National Natural Science Foundation of China(Nos.51973150 and 21674076)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJA320009)a Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Piezoelectric poly(vinylidene fluoride)(PVDF)has received considerable attention due to its ability of interconverting mechanical into electric energies and potential applications in wearable electronics.To achieve piezoelectricity,it is important to simultaneously control the formation of polar phases,crystallinity,and dipole alignments in PVDF-based films.Here we demonstrate that piezoelectricity can be obtained by directly hot-pressing PVDF films sandwiched between chitosan or cellulose films.The electrostatic interactions between PVDF and chitosan or cellulose enabled an exceptional high content of polar phases(β-andγ-phases)up to 90%and a measured piezoelectric charge coefficient d_(33)of up to-30 pC/N.This study provides a simple and low-cost approach for obtaining piezoelectric PVDF films used for sensors,actuators,and energy harvesters.
文摘Background:Retinol dehydrogenase 8(RDH8)is a 312-amino acid(aa)protein involved in the visual cycle.Bound to the outer segment disk membranes of photoreceptors,it reduces all-trans-retinal to all-trans-retinol1 as one of the rate-limiting steps of the visual cycle2.RDH8 is a member of the short-chain dehydrogenase/reductase family.Its C-terminal segment allows its membrane-anchoring through the postulated presence of an amphipathicα-helix and of 1 to 3 acyl groups at positions 299,302 and 3043.The secondary structure and membrane binding characteristics of RDH8 and its C-terminal segment have not yet been described.Methods:To evaluate the membrane binding of RDH8,the full-length protein(aa 1-312),a truncated form(aa 1-296),its C-terminal segment(aa 281-312 and 297-312)as well as different additional variants of this segment were used.The truncated protein binds membranes less efficiently than the full-length form.Thus,the C-terminal segment of RDH8 is essential for the binding and has thus been further examined.The intrinsic fluorescence of tryptophan residues at positions 289 and 310 of the wild-type C-terminal segment of RDH8 and the mutants W289F,W310F and W310R have thus been used to determine their extent of binding to lipid vesicles and to monitor their local environment.Unilamellar lipid vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)or a mixture of POPC and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(POPS)were used to mimic the phospholipid content of the outer segment disk membranes of photoreceptors.Results:An increase in fluorescence intensity and in fluorescence lifetime is observed upon increasing the concentration of lipid vesicles.These data allowed calculating values of partition coefficient of the C-terminal segment of RDH8 varying between Kp=1.1 E6 to 1.7 E6.It is noteworthy that the observation of a more intense shift to lower wavelengths upon membrane binding of the mutant W310R and W310F indicates a deeper incorporation of the remaining tryptophan residue at position 289 into the lipid bilayer.The secondary structure of the C-terminal segment of RDH8 observed by circular dichroism and infrared spectroscopy shows a superposition ofα-helical,β-turn and unordered structures.Conclusions:The peptides derived from the C-terminal segment of RDH8 show a strong binding to lipid vesicles.These strength of binding is independent of the type of lipid and the presence of a mutation.
基金supported by the National Science Foundation of China(Grant No.5202780089)the Fundamental Research Funds for the Central Universities(HUST:2172020kfy XJJS089)。
文摘The development of polymer-based solid-state batteries is severely limited by the low ionic conductivity of solid polymer electrolyte and the instable interface between polymer electrolyte and Li-metal anode.In this work,lithium iodide(LiI)as a bifunctional additive was introduced into the poly(ethylene oxide)(PEO)-based electrolyte to improve the ionic conductivity and to construct a stable interphase at the Li/PEO interface.I-anions offer a strong electrostatic interaction with hydrogen atoms on PEO chains(HPEO)and forming massive I–H bonds that cross-link PEO chains,decrease crystallinity of PEO,and thus improve Li~+interchain transport.In addition,LiI participates in the formation of an inorganic-rich interphase layer,which decreases the energy barrier of Li+transport across the interface and thus inhibits the growth of lithium dendrites.As a result,the composite PEO electrolyte with 2 wt%LiI(PEO-2 LiI)presents a very high ionic conductivity of 2.1×10^(-4) S cm-1 and a critical current density of 2.0 m A cm^(-2) at 45°C.Li symmetric cell with this PEO-2 LiI electrolyte exhibits a long-term cyclability over 600 h at 0.2 m A cm^(-2).Furthermore,solid-state LiFePO_(4) and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) batteries with the PEO-2 LiI electrolyte show an impressive electrochemical performance with outstanding cycling stability and rate capability at 45°C.
基金Supported by Research Foundation of Overseas Chinese Affairs Office,the State Council,P.R.China,and FujianProvincial Science and Technology Creation Foundation for Young Researchers(No.2 0 0 1J0 2 3)
文摘Sieve effect, complexation, ionic exchange, electrostatic interaction, hydrogen bonding, hydrophobic interaction, and molecular recognition based on molecular imprinting are comprehensively discussed.
基金supported by the National Natural Science Foundation of China(21776093,21376089,41976203,21506178,21908066)。
文摘Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zwitterionic materials,nucleic acids,proteins,biomembranes and etc.,where the electrostatic interactions are of special significance.Several methods have been available for treating the electrostatic interactions in explicit and implicit solvent models.Accurate and efficient treatment of such interactions has therefore always been one of the most challenging issues in classical molecular dynamics simulations due to their inhomogeneity and long-range characteristics.Currently,two major challenges remain in the application field of electrostatic interactions in molecular simulations;(i)improving the representation of electrostatic interactions while reducing the computational costs in molecular simulations;(ii)revealing the role of electrostatic interactions in regulating the specific properties of complex fluids.In this review,the calculation methods of electrostatic interactions,including basic principles,applicable conditions,advantages and disadvantages are summarized and compared.Subsequently,the specific role of electrostatic interactions in governing the properties and behaviors of different complex fluids is emphasized and explained.Finally,challenges and perspective on the computational study of charged systems are given.
基金Funded by the National Natural Science Foundation of China(21576216)
文摘Adsorption of poly(L-lysine) on surface-attached poly(methacrylic acid) monolayers formed through in situ free radical polymerization was investigated. A strong "template effect" was observed for the adsorption of poly(L-lysine) on poly(methacrylic acid) layers, which were perpendicularly grown from the surface of substrates. The adsorbed amount of poly(amino acid) increases linearly with the increase in initial layer thickness of poly(methacrylic acid) monolayers. In addition, the adsorbed poly(amino acid) is relatively stable in medium concentration of salt solution but can be completely released from the brush in high salt concentration.
文摘Stabilization of proteins in delivery devices and design of appropriate protein carriers are major research issues due to the extreme sensitivity of proteins.Previously,negatively charged nanoparticles,consisting of poly(lactic-co-glycolic acid)(PLGA)and poly(styrene-co-4–styrene-sulfonate)(PSS),showed considerably high loading capacity for positively charged model protein lysozyme depending on the surface charge density of nanoparticles.