Covalent organic framework nanosheets(CONs)with porous crystalline features and ultrathin thickness are ideal candidates as membrane building blocks to form well-defined transfer nanochannels.The formidable challenge ...Covalent organic framework nanosheets(CONs)with porous crystalline features and ultrathin thickness are ideal candidates as membrane building blocks to form well-defined transfer nanochannels.The formidable challenge behind self-supporting CONs membrane lies in weak noncovalent interlayer interactions and thus loose stacking,insufficient strength and structure stabilities.Herein,we propose the fabrication of interlayer force-strengthened freestanding CONs membrane through the electrostatic attraction bridge effect of positively-charged amino-rich CONs(CON-NH2)to negatively-charged sulfonated CONs(CON-SO_(3)H).Ultrathin and large lateral sized CON-SO_(3)H and CON-NH2 are synthesized,followed by restacking to prepare freestanding CONs membrane with CON-SO_(3)H as the membrane bulk.Benefiting from effective interlayer interconnection due to strong electrostatic interaction,the obtained CON-SO_(3)H/CON-NH2 membrane displays features of ultrahigh integrity,dense stacking,eminent water/acid/base/organic solvents stabilities and mechanical strength(109 MPa).The shortened-SO_(3)H distance contributes to construct site-continuous transfer pathways,and the deprotonated-SO_(3)H and protonated-NH2 form acid-base pairs to decrease interfacial resistance,which impart membrane superior proton conductivity of 486 mS cm^(-1)(80℃,100%RH).This interlayer force enhancement strategy offers a promising perspective on achieving densely-stacked CONs membrane with ultrahigh mechanical property and conduction performance for fuel cell application.展开更多
The interaction between membrane structures and their environment can be either static or dynamic. Static interaction refers to interaction with static air, while dynamic interaction refers to wind and its effects. Th...The interaction between membrane structures and their environment can be either static or dynamic. Static interaction refers to interaction with static air, while dynamic interaction refers to wind and its effects. They can be evaluated by two parameters, added mass and radiation/aerodynamic damping, which are experimentally investigated in this study. The study includes the effects of both the static and dynamic interaction on structural dynamic characteristics, and the relationship between the interaction parameters and the covered area of a membrane structure for the static interaction and the relationship between the interaction parameters and wind direction and speed for the dynamic interaction. Experimental data show that the dynamic interaction is strongly correlated with the structural modes, i.e., the interaction of the symmetric modes is much larger than the anti-synmletric modes; and the influence of the dynamic interaction is significant in wind-induced response analysis and cannot be ignored. In addition, it is concluded that the structural natural frequency is remarkably decreased by this interaction, and the frequency band is significantly broadened.展开更多
Membrane filtration combined with pre-coagulation has advantages in advanced wastewater treatment. As a model of a microbial polysaccharide, research on the effect of sodium alginate(SA) on alum hydrolysis has been ra...Membrane filtration combined with pre-coagulation has advantages in advanced wastewater treatment. As a model of a microbial polysaccharide, research on the effect of sodium alginate(SA) on alum hydrolysis has been rare; therefore, it is necessary to gain insight into the interface interaction between SA molecules and Al species, and the role SA plays during floc formation. In this study, the interaction mechanism between SA and Al species has been investigated, by evaluating the effect of SA on floc characteristics and membrane fouling during coagulation–ultrafiltration with different Al species coagulants(AlCl3 and preformed Al13). Al 2 p X-ray photoelectron spectroscopy(XPS) confirmed that the complexation of ligands and Al species strongly affects the reaction pathways for Al hydrolysis and the final nature of the flocs, as Al13 can be decomposed into octahedral precipitates when SA is added. The presence of SA can affect floc properties, which have important impacts on the characteristics of the cake layer and membrane fouling. Due to the bridging ability of SA, the floc strength increased by about 50% using Ala, which was much better than preformed Al13, with a percentage increase of only about 6%. Moreover,the recovery factor of HA-flocs was decreased from 96% to 43% with SA addition of 0.5 mg/L.It was concluded that SA can affect the characteristics of the cake layer and membrane fouling through participating in the formation of primary flocs and altering the Al hydrolysis pathway.展开更多
It is very important for gas-structure interaction between compressible ideal gas and elastic structure of space folded membrane booms during the inflatable deployment. In order to study this gas-structure interaction...It is very important for gas-structure interaction between compressible ideal gas and elastic structure of space folded membrane booms during the inflatable deployment. In order to study this gas-structure interaction problem, Arbitrary Lagrangian-Eulerian （ALE） finite element method was employed. Gas-structure interaction equation was built based on equilibrium integration relationship, and solved by operator split method. In addition, numerical analysis of V-shape folded membrane booms inflated by gas was given, the variation of inner pressure as well as deployment velocities of inflatable boom at different stage were simulated. Moreover, these results are consistent with the experiment of the same boom~ which shows that both ALE method and operator split method are feasible and reliable methods to study gas-structure interaction problem.展开更多
We studied the incorporation of hydrophobic drug Taxol into a solid lipid matrices by FTIR spectroscopy. Lipid arrays containing different molar fractions of the drug were made and deposited on the spectrometer glass ...We studied the incorporation of hydrophobic drug Taxol into a solid lipid matrices by FTIR spectroscopy. Lipid arrays containing different molar fractions of the drug were made and deposited on the spectrometer glass window substrates for obtaining multilayer stacks. The drug induced an alteration of lipid array spacings, indicating the drug-lipid recognition. Using excess amounts of Taxol provide information on extrapolations on its cellular solubility in biomembranes. The data obtained could be used further for developing novel anticancer drug formulations, as well as for elucidating its novel cellular pharmacological targets.展开更多
Objective: While substituted phenols have a variety of pharmacological activity, the mechanism underlying their anesthetic effects remains uncertain especially about the critical target. We characterized the lipid mem...Objective: While substituted phenols have a variety of pharmacological activity, the mechanism underlying their anesthetic effects remains uncertain especially about the critical target. We characterized the lipid membrane-interacting properties of different phenols by comparing with general anesthetic propofol and local anesthetics. Based on the results, we also studied the pharmacological effects possibly associated with their membrane interactivities. Methods: 1,6-Diphenyl-1,3,5-hexatriene-labeled lipid bilayer membranes were prepared with 1,2-dipalmitoyl-phosphatidylcholine as model membranes and with different phospholipids and cholesterol to mimic neuronal membranes. These membrane preparations were treated with phenols and anesthetics at 1 - 200 μM, followed by measuring the fluorescence polarization to determine the membrane interactivities to change membrane fluidity. Antioxidant effects were fluorometrically determined using diphenyl-1-pyrenylphosphine-incorporated liposomes which were treated with 10 - 100 μM phenols, and then peroxidized with 10 μM peroxynitrite. Results: Several phenols interacted with the model membranes and the neuronal mimetic membranes to increase their fluidity at 1 - 10 μM as well as lidocaine and bupivacaine did at 50 - 200 μM. Their comparative potencies were propofol > thymol > isothymol > guaiacol > phenol > eugenol, and bupivacaine > lidocaine, consistent with the rank order of neuro-activity. These phenols inhibited membrane lipid peroxidation at 10 and 100 μM with the potencies correlating to their membrane interactivities. Conclusion: The structure-specific membrane interaction is at least in part responsible for the pharmacology of anesthetic alkylphenols. Membrane-interacting antioxidant alkylphenols may be protective against the peroxynitrite-relating ischemia/reperfusion injury.展开更多
Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes'...Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes' hydrophobicity was measured by n-octanol/buffer system.Results The ampholytes, similar to bases, generally exhibited higher membrane affinity than expectedfrom their hydrophobicity, resulting from the attractive polar interaction with phospholipidmembrane. Furthermore, the strength of additional polar interaction with membrane (Δlg k_(IAM)) wasthen calculated. The Δlg k_(IAM) values were far greater for bases and ampholytes ranging from0.50 - 1.39, than those for acids and neutrals with the scope from - 0.55 - 0.44. ConclusionConsidering the microspecies distribution of amphoteric molecules, it was assumed that not onlyneutral and positive but also zwitterionic microspecies are capable of partitioning into orderedamphoteric lipid membrane with complementarily conformational and energetically favorableinteractions.展开更多
Research on protein-membrane interactions has been undeveloped due to the lack of proper techniques to detect the position of proteins at membranes because membranes are usually only about 4-nm thick. We have recently...Research on protein-membrane interactions has been undeveloped due to the lack of proper techniques to detect the position of proteins at membranes because membranes are usually only about 4-nm thick. We have recently developed a new method named surface-induced fluorescence attenuation （SIFA） to track both vertical and lateral kinetics of a single labelling dye in supported lipid bilayers. It takes advantage of strong interaction between a light-emitting dye and a partially reflecting surface. By applying the technique to membrane proteins being fluorescently labelled at different residues, here we show that SIFA can measure not only the insertion depth of a dye inside a lipid bilayer, but also the position of a dye in solution near the surface. SIFA can therefore be used to study membrane proteins of various types.展开更多
Removing H_(2)S and CO_(2)is of great significance for natural gas purification.With excellent gas affinity and tunable structure,ionic liquids(ILs) have been regarded as nontrivial candidates for fabricating polymer-...Removing H_(2)S and CO_(2)is of great significance for natural gas purification.With excellent gas affinity and tunable structure,ionic liquids(ILs) have been regarded as nontrivial candidates for fabricating polymer-based membranes.Herein,we firstly reported the incorporation of protic ILs (PILs) having ether-rich and carboxylate sites (ECPILs) into poly(ether-block-amide)(Pebax) matrix for efficient separation H_(2)S and CO_(2)from CH_(4).Notably,the optimal permeability of H_(2)S reaches up to 4310 Barrer (40C,0.50 bar) in Pebax/ECPIL membranes,along with H_(2)S/CH_(4)and (H_(2)StCO_(2))/CH_(4)selectivity of 97.7 and 112.3,respectively.These values are increased by 1125%,160.8%and 145.9%compared to those in neat Pebax membrane.Additionally,the solubility and diffusion coefficients of the gases were measured,demonstrating that ECPIL can simultaneously strengthen the dissolution and diffusion of H_(2)S and CO_(2),thus elevating the permeability and permselectivity.By using quantum chemical calculations and FT-IR spectroscopy,the highly reversible multi-site hydrogen bonding interaction between ECPILs and H_(2)S was revealed,which is responsible for the fast permeation of H_(2)S and good selectivity.Furthermore,H_(2)S/CO_(2)/CH_(4)(3/3/94 mol/mol) ternary mixed gas can be efficiently and stably separated by Pebax/ECPIL membrane for at least 100 h.Overall,this work not only illustrates that PILs with ether-rich and carboxylate hydrogen bonding sites are outstanding materials for simultaneous removal of H_(2)S and CO_(2),but may also provide a novel insight into the design of membrane materials for natural gas upgrading.展开更多
Cell membranes play a crucial role in many biological functions of cells. A small change in the composition of cell membranes can strongly influence the functions of membrane-associated proteins, such as ion and water...Cell membranes play a crucial role in many biological functions of cells. A small change in the composition of cell membranes can strongly influence the functions of membrane-associated proteins, such as ion and water channels, and thus mediate the chemical and physical balance in cells. Such composition change could originate from the introduction of short-chain alcohols, or other anesthetics into membranes. In this work, we have applied sum frequency generation vibrational spectroscopy （SFG-VS）, supplemented by attenuated total reflectance Fourier transform infrared spectroscopy （ATR-FTIR）, to investigate interaction between methanol and 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine （d54-DMPC） lipid bilayers. Lipid＇s hydrocarbon interior is deuterated while its head group is hydrogenated. At the same time, CH3 symmetric stretch from methanol and lipid head amine group has different frequency, thus we can distinguish the behaviors of methanol, lipid head amine group, and lipid hydrocarbon interior. Based on the spectral feature of the bending mode of the water molecules replaced by methanol, we determined that the methanol molecules are intercalated into the region between amine and phosphate groups at the lipid hydrophilic head. The dipole of CH3 groups of methanol and lipid head, and the water O-H M1 adopt the same orientation directions. The introduction of methanol into the lipid hydrophilic head group can strongly perturb the entire length of the alkyl chains, resulting that the signals of CD2 and CD3 groups from both leaflets can not cancel each other.展开更多
Motivated by recent experimental observations that carbon nanotubes （CNT） can enter animal cells, here we conduct coarse grained molecular dynamics and theoretical studies of the intrinsic interaction mechanisms bet...Motivated by recent experimental observations that carbon nanotubes （CNT） can enter animal cells, here we conduct coarse grained molecular dynamics and theoretical studies of the intrinsic interaction mechanisms between CNT＇s and lipid bilayer. The results indicate that CNT-cell interaction is dominated by van der Waals and hydrophobic forces, and that CNT＇s with sufficiently small radii can directly pierce through cell membrane while larger tubes tend to enter cell via a wrapping mechanism. Theoretical models are proposed to explain the observed size effect in transition of entry mechanisms.展开更多
A series of sulfonated polyimide copolymers as novel proton exchange materials were synthesized by the polycondensation of 1,4,5,8-naphthalene-tetracarboxylic dianhydride （NTDA）, sulfonated diamine based on pyridine...A series of sulfonated polyimide copolymers as novel proton exchange materials were synthesized by the polycondensation of 1,4,5,8-naphthalene-tetracarboxylic dianhydride （NTDA）, sulfonated diamine based on pyridine group and diamine containing N-phenyl-1,2,4-triazole moiety. Flexible, transparent and tough membranes with high thermal stability and good mechanical properties were obtained. They exhibited good stability in boiling water and Fenton＇s reagent at 80 ℃. More interestingly, a nonlinear relationship between proton conductivities of the resulting membranes and the degree of sulfonation （DS） was observed. The membrane with 50% DS exhibited the maximum proton conductivity, which was due to the combinational contributions of sulfonic acid and N-pheny-1,2,4-triazole groups. Thus, the N-phenyl-l,2,4- triazole moiety in this study not only can depress water absorption but also increase proton conductivity, especially at low DS.展开更多
Aim： To investigate the possible functions of human sperm membrane protein （hSMP-1） in the process of fertilization. Methods： A 576-bp cDNA fragment of HSD-1 gene coding for the extracellular domain of hSMP-1 was ...Aim： To investigate the possible functions of human sperm membrane protein （hSMP-1） in the process of fertilization. Methods： A 576-bp cDNA fragment of HSD-1 gene coding for the extracellular domain of hSMP-1 was cloned and expressed. The localization of this protein on human and mouse sperm was determined by indirect immunofluorescent staining by using anti-recombinant hSMP-1 （anti-rhSMP-1） antibodies. Sperm acrosome reaction and spermzona pellucida （ZP） binding assay were carried out in 10-week-old BALB/c mice. Results： Recombinant hSMP-1 was successfully cloned and expressed. The expression of the native protein was limited on the acrosome of human and mouse sperm. Treatment of anti-rhSMP-1 antibodies significantly decreased the average number of sperms bound to each egg. Meanwhile, the percentage of acrosome reaction was decreased in comparison to pre-immune control after treatment with anti-rhSMP-1 （P 〈 0.05）. Conclusion： The results suggest that anti-rhSMP-1 antibody inhibited mouse acrosome reaction and sperm-ZP binding.展开更多
A novel capillary electrophoresis method coupled with on-line microdialysis using an attachable electrode has been developed to study the interaction of macromolecule with small molecule. The binding constants of bovi...A novel capillary electrophoresis method coupled with on-line microdialysis using an attachable electrode has been developed to study the interaction of macromolecule with small molecule. The binding constants of bovine serum album (BSA) with D,L-tryptophan (Trp), sulfamethoxazole (SMZ) with trypsin and chymotrypsin were determined. These values are 2.3 x 10(4)L/mol for BSA-L-Trp; 1.77 x 10(3) L/mol for BSA-D-Trp in pH 7.4, 50 mmol/ L phosphate; 1.4 x 10(4) L/mol for SMZ- trypsin and 6.0 x 10(3) L/mol for SMZ-chymotrypsin in pH 6.5, 25 mmol/L Tris buffer. The proposed method has merits of speed, low sample consumption and readily available to be performed in desired physiological conditions.展开更多
BACKGROUND The therapeutic potential of mesenchymal stem cells(MSCs)in the form of threedimensional spheroids has been extensively demonstrated.The underlying mechanisms for the altered cellular behavior of spheroids ...BACKGROUND The therapeutic potential of mesenchymal stem cells(MSCs)in the form of threedimensional spheroids has been extensively demonstrated.The underlying mechanisms for the altered cellular behavior of spheroids have also been investigated.Cell membrane fluidity is a critically important physical property for the regulation of cell behavior,but it has not been studied for the spheroid-forming cells to date.AIM To explore the association between cell membrane fluidity and the morphological changes of MSC spheroids on the surface of biomaterials to elucidate the role of membrane fluidity during the spheroid-forming process of MSCs.METHODS We generated three-dimensional(3D)MSC spheroids on the surface of various culture substrates including chitosan(CS),CS-hyaluronan(CS-HA),and polyvinyl alcohol(PVA)substrates.The cell membrane fluidity and cell morphological change were examined by a time-lapse recording system as well as a highresolution 3D cellular image explorer.MSCs and normal/cancer cells were prestained with fluorescent dyes and co-cultured on the biomaterials to investigate the exchange of cell membrane during the formation of heterogeneous cellular spheroids.RESULTS We discovered that vesicle-like bubbles randomly appeared on the outer layer of MSC spheroids cultured on different biomaterial surfaces.The average diameter of the vesicle-like bubbles of MSC spheroids on CS-HA at 37℃ was approximately 10μm,smaller than that on PVA substrates(approximately 27μm).Based on time-lapse images,these unique bubbles originated from the dynamic movement of the cell membrane during spheroid formation,which indicated an increment of membrane fluidity for MSCs cultured on these substrates.Moreover,the membrane interaction in two different types of cells with similar membrane fluidity may further induce a higher level of membrane translocation during the formation of heterogeneous spheroids.CONCLUSION Changes in cell membrane fluidity may be a novel path to elucidate the complicated physiological alterations in 3D spheroid-forming cells.展开更多
Metyrapone (2-methyl-1,2-di-3-pyridyl-1-propanone) is a drug largely used as inhibitor of glucocorticoid synthesis. Although its binding to various proteins has been well indentified, its accurate molecular mechanism ...Metyrapone (2-methyl-1,2-di-3-pyridyl-1-propanone) is a drug largely used as inhibitor of glucocorticoid synthesis. Although its binding to various proteins has been well indentified, its accurate molecular mechanism of action remains unknown. Therefore, the interactions of metyrapone (MET) with various membrane components such as phospholipids, cholesterol, their corresponding polar heads and a model serine containing peptide have been investigated by NMR and ESR methods. It was found that neither cholesterol nor most of the phospholipids tested, nor dimyristin exhibit any interaction with MET, except phosphatidylserine (DMPS). Furthermore, only serine bearing polar head (O-phosphoserine) showed an association with MET (stoechiometry 1:1, Kd = 3200M-1). As similar observations were also performed on serine alone and in the presence of the serine containing model peptide, (NASDSDGQDL), a possible implication of these interactions in the binding recognition of MET on serine-containing active site was finally tested and discussed.展开更多
The mirid bug Apolygus lucorum(Hemiptera:Miridae)is a polyphagous pest that affects a wide range of host plants.Its control remains challenging mainly due to its rapid reproduction,necessitating an understanding of se...The mirid bug Apolygus lucorum(Hemiptera:Miridae)is a polyphagous pest that affects a wide range of host plants.Its control remains challenging mainly due to its rapid reproduction,necessitating an understanding of sex pheromone communication.The recognition of sex pheromones is vital for courtship and mating behaviors,and is mediated by various chemosensory-associated proteins.Among these,sensory neuron membrane protein(SNMP),a CD36-related protein,is suggested to play crucial roles in detecting sex pheromones.In this study,we employed transcriptomic and genomic data from A.lucorum and phylogenetic approaches,and identified four putative SNMP genes(AlucSNMP1a,AlucSNMP1b,AlucSNMP2a,and AlucSNMP2b)with full open reading frames.Expression analysis revealed the ubiquitous presence of AlucSNMP transcripts in multiple tissues,with only AlucSNMP1a exhibiting male-biased expression in the antennae,suggesting its potential role in male chemosensation.Functional analysis using the Xenopus oocyte expression system,coupled with two-electrode voltage clamp recording,demonstrated that the co-expression of AlucSNMP1a with specific pheromone receptors(PRs)and the Odorant receptor co-receptor(Orco)significantly enhanced electrophysiological responses to sex pheromones compared to the co-expression of PRs and Orco alone.Moreover,the results indicated that the presence of AlucSNMP1a not only affected the responsiveness to sex pheromones but also influenced the kinetics(activation and inactivation)of the induced signals.In contrast,the co-expression of AlucSNMP1b with AlucPR/Orco complexes had no impact on the inward currents induced by two pheromone compounds.An examination of the selective pressures on SNMP1 genes across 20 species indicated strong purifying selection,implying potential functional conservation in various insects.These findings highlight the crucial role of AlucSNMP1a in the response to sex pheromones.展开更多
Carbon monoxide releasing molecules (CORMs) have been recently developed for research and pharmacological purposes. A considerable amount of studies demonstrated a wide spectrum of biological activities for lipophilic...Carbon monoxide releasing molecules (CORMs) have been recently developed for research and pharmacological purposes. A considerable amount of studies demonstrated a wide spectrum of biological activities for lipophilic CORM-2 (tricarbonyldichlororuthenium (II) dimer). It is generally accepted that the liberated gas provides the specific activities to CORMs, with a little attention paid to any possible effect of complementary core molecules. However, the versatile repertoire of actions attributed to CORM-2 is surprisingly wide for CO, a molecule with the sole chemical activity of binding to ferrous iron in protein prosthetic groups. The study was designed to analyze CORM-2 and its core molecule (“i”CORM) activities at a molecular level. With respect to the hydrophobic nature of the compounds, we followed their interactions with several amphipathic entities: the heme sites of hemoproteins, heme binding proteins and cell membranes. CORM-2/“i”CORM decreased the Soret optical density of hemoglobin and myoglobin, indicating that both compounds interact with the protein amphipathic site in the heme pocket. Pre-addition of CORM-2/“i”CORM to the apo-forms of the plasma heme binding proteins, hemopexin and albumin, partially abolished their heme binding capacity. In contrast, the compounds had no effect on the preformed heme-protein complexes. Addition of CORM-2/“i”- CORM to blood or isolated erythrocytes revealed aggregation of the cells or lysis, depending on the rea-gent-to-cells ratio. It was concluded that the ruthenium containing core molecule of CORM-2 may be physiologically active due to non-specific hydrophobic interactions. As each type of CORMs is expected to have a different mode of action beyond CO activity, their potential therapeutic uses will require clarification.展开更多
Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing tech...Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight characteristics.The investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting surface.The focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type gust.At a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction simulations.First,the numerical results are validated by experimental data from force and moment,flow field,and deformation measurements.Second,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic membrane.For all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical results.During the decay of the gust,they differ more the higher the aspect ratio of the wing.When considering the flow field,the main differences are due to the separation behavior on the upper side of the wing.The flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the former.Only at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.展开更多
文摘Covalent organic framework nanosheets(CONs)with porous crystalline features and ultrathin thickness are ideal candidates as membrane building blocks to form well-defined transfer nanochannels.The formidable challenge behind self-supporting CONs membrane lies in weak noncovalent interlayer interactions and thus loose stacking,insufficient strength and structure stabilities.Herein,we propose the fabrication of interlayer force-strengthened freestanding CONs membrane through the electrostatic attraction bridge effect of positively-charged amino-rich CONs(CON-NH2)to negatively-charged sulfonated CONs(CON-SO_(3)H).Ultrathin and large lateral sized CON-SO_(3)H and CON-NH2 are synthesized,followed by restacking to prepare freestanding CONs membrane with CON-SO_(3)H as the membrane bulk.Benefiting from effective interlayer interconnection due to strong electrostatic interaction,the obtained CON-SO_(3)H/CON-NH2 membrane displays features of ultrahigh integrity,dense stacking,eminent water/acid/base/organic solvents stabilities and mechanical strength(109 MPa).The shortened-SO_(3)H distance contributes to construct site-continuous transfer pathways,and the deprotonated-SO_(3)H and protonated-NH2 form acid-base pairs to decrease interfacial resistance,which impart membrane superior proton conductivity of 486 mS cm^(-1)(80℃,100%RH).This interlayer force enhancement strategy offers a promising perspective on achieving densely-stacked CONs membrane with ultrahigh mechanical property and conduction performance for fuel cell application.
基金National Natural Science Foundation of China Under Grant No. 50725826, 90815021
文摘The interaction between membrane structures and their environment can be either static or dynamic. Static interaction refers to interaction with static air, while dynamic interaction refers to wind and its effects. They can be evaluated by two parameters, added mass and radiation/aerodynamic damping, which are experimentally investigated in this study. The study includes the effects of both the static and dynamic interaction on structural dynamic characteristics, and the relationship between the interaction parameters and the covered area of a membrane structure for the static interaction and the relationship between the interaction parameters and wind direction and speed for the dynamic interaction. Experimental data show that the dynamic interaction is strongly correlated with the structural modes, i.e., the interaction of the symmetric modes is much larger than the anti-synmletric modes; and the influence of the dynamic interaction is significant in wind-induced response analysis and cannot be ignored. In addition, it is concluded that the structural natural frequency is remarkably decreased by this interaction, and the frequency band is significantly broadened.
基金supported by the National Natural Science Foundation of China(Nos.51338010,51608515,21677156,51708005)the Fundamental Research Funds for the Central Universities of Huazhong University of Science and Technology(No.2016YXMS284)+1 种基金the National Water Pollution Control and Treatment Science and Technology Major Project(No.2015ZX07406005-002)the State Key Laboratory of Separation Membranes and Membrane Processes(Tianjin Polytechnic University)(No.M1-20160)
文摘Membrane filtration combined with pre-coagulation has advantages in advanced wastewater treatment. As a model of a microbial polysaccharide, research on the effect of sodium alginate(SA) on alum hydrolysis has been rare; therefore, it is necessary to gain insight into the interface interaction between SA molecules and Al species, and the role SA plays during floc formation. In this study, the interaction mechanism between SA and Al species has been investigated, by evaluating the effect of SA on floc characteristics and membrane fouling during coagulation–ultrafiltration with different Al species coagulants(AlCl3 and preformed Al13). Al 2 p X-ray photoelectron spectroscopy(XPS) confirmed that the complexation of ligands and Al species strongly affects the reaction pathways for Al hydrolysis and the final nature of the flocs, as Al13 can be decomposed into octahedral precipitates when SA is added. The presence of SA can affect floc properties, which have important impacts on the characteristics of the cake layer and membrane fouling. Due to the bridging ability of SA, the floc strength increased by about 50% using Ala, which was much better than preformed Al13, with a percentage increase of only about 6%. Moreover,the recovery factor of HA-flocs was decreased from 96% to 43% with SA addition of 0.5 mg/L.It was concluded that SA can affect the characteristics of the cake layer and membrane fouling through participating in the formation of primary flocs and altering the Al hydrolysis pathway.
基金supported by the National Natural Science Foundation of China (10902032)the National Key Laboratory Opening Funding of Advanced Composites in Special Environments (HIT.KLOF.2009035)
文摘It is very important for gas-structure interaction between compressible ideal gas and elastic structure of space folded membrane booms during the inflatable deployment. In order to study this gas-structure interaction problem, Arbitrary Lagrangian-Eulerian （ALE） finite element method was employed. Gas-structure interaction equation was built based on equilibrium integration relationship, and solved by operator split method. In addition, numerical analysis of V-shape folded membrane booms inflated by gas was given, the variation of inner pressure as well as deployment velocities of inflatable boom at different stage were simulated. Moreover, these results are consistent with the experiment of the same boom~ which shows that both ALE method and operator split method are feasible and reliable methods to study gas-structure interaction problem.
文摘We studied the incorporation of hydrophobic drug Taxol into a solid lipid matrices by FTIR spectroscopy. Lipid arrays containing different molar fractions of the drug were made and deposited on the spectrometer glass window substrates for obtaining multilayer stacks. The drug induced an alteration of lipid array spacings, indicating the drug-lipid recognition. Using excess amounts of Taxol provide information on extrapolations on its cellular solubility in biomembranes. The data obtained could be used further for developing novel anticancer drug formulations, as well as for elucidating its novel cellular pharmacological targets.
文摘Objective: While substituted phenols have a variety of pharmacological activity, the mechanism underlying their anesthetic effects remains uncertain especially about the critical target. We characterized the lipid membrane-interacting properties of different phenols by comparing with general anesthetic propofol and local anesthetics. Based on the results, we also studied the pharmacological effects possibly associated with their membrane interactivities. Methods: 1,6-Diphenyl-1,3,5-hexatriene-labeled lipid bilayer membranes were prepared with 1,2-dipalmitoyl-phosphatidylcholine as model membranes and with different phospholipids and cholesterol to mimic neuronal membranes. These membrane preparations were treated with phenols and anesthetics at 1 - 200 μM, followed by measuring the fluorescence polarization to determine the membrane interactivities to change membrane fluidity. Antioxidant effects were fluorometrically determined using diphenyl-1-pyrenylphosphine-incorporated liposomes which were treated with 10 - 100 μM phenols, and then peroxidized with 10 μM peroxynitrite. Results: Several phenols interacted with the model membranes and the neuronal mimetic membranes to increase their fluidity at 1 - 10 μM as well as lidocaine and bupivacaine did at 50 - 200 μM. Their comparative potencies were propofol > thymol > isothymol > guaiacol > phenol > eugenol, and bupivacaine > lidocaine, consistent with the rank order of neuro-activity. These phenols inhibited membrane lipid peroxidation at 10 and 100 μM with the potencies correlating to their membrane interactivities. Conclusion: The structure-specific membrane interaction is at least in part responsible for the pharmacology of anesthetic alkylphenols. Membrane-interacting antioxidant alkylphenols may be protective against the peroxynitrite-relating ischemia/reperfusion injury.
文摘Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes' hydrophobicity was measured by n-octanol/buffer system.Results The ampholytes, similar to bases, generally exhibited higher membrane affinity than expectedfrom their hydrophobicity, resulting from the attractive polar interaction with phospholipidmembrane. Furthermore, the strength of additional polar interaction with membrane (Δlg k_(IAM)) wasthen calculated. The Δlg k_(IAM) values were far greater for bases and ampholytes ranging from0.50 - 1.39, than those for acids and neutrals with the scope from - 0.55 - 0.44. ConclusionConsidering the microspecies distribution of amphoteric molecules, it was assumed that not onlyneutral and positive but also zwitterionic microspecies are capable of partitioning into orderedamphoteric lipid membrane with complementarily conformational and energetically favorableinteractions.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574382)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDJ-SSW-SYS014)
文摘Research on protein-membrane interactions has been undeveloped due to the lack of proper techniques to detect the position of proteins at membranes because membranes are usually only about 4-nm thick. We have recently developed a new method named surface-induced fluorescence attenuation （SIFA） to track both vertical and lateral kinetics of a single labelling dye in supported lipid bilayers. It takes advantage of strong interaction between a light-emitting dye and a partially reflecting surface. By applying the technique to membrane proteins being fluorescently labelled at different residues, here we show that SIFA can measure not only the insertion depth of a dye inside a lipid bilayer, but also the position of a dye in solution near the surface. SIFA can therefore be used to study membrane proteins of various types.
基金sponsored by the National Natural Science Foundation of China (Nos. 22308145, 22208140, 22178159, 22078145)Natural Science Foundation of Jiangsu Province (BK20230791)Postgraduate Research Innovation Program of Jiangsu Province (KYCX24_0165)。
文摘Removing H_(2)S and CO_(2)is of great significance for natural gas purification.With excellent gas affinity and tunable structure,ionic liquids(ILs) have been regarded as nontrivial candidates for fabricating polymer-based membranes.Herein,we firstly reported the incorporation of protic ILs (PILs) having ether-rich and carboxylate sites (ECPILs) into poly(ether-block-amide)(Pebax) matrix for efficient separation H_(2)S and CO_(2)from CH_(4).Notably,the optimal permeability of H_(2)S reaches up to 4310 Barrer (40C,0.50 bar) in Pebax/ECPIL membranes,along with H_(2)S/CH_(4)and (H_(2)StCO_(2))/CH_(4)selectivity of 97.7 and 112.3,respectively.These values are increased by 1125%,160.8%and 145.9%compared to those in neat Pebax membrane.Additionally,the solubility and diffusion coefficients of the gases were measured,demonstrating that ECPIL can simultaneously strengthen the dissolution and diffusion of H_(2)S and CO_(2),thus elevating the permeability and permselectivity.By using quantum chemical calculations and FT-IR spectroscopy,the highly reversible multi-site hydrogen bonding interaction between ECPILs and H_(2)S was revealed,which is responsible for the fast permeation of H_(2)S and good selectivity.Furthermore,H_(2)S/CO_(2)/CH_(4)(3/3/94 mol/mol) ternary mixed gas can be efficiently and stably separated by Pebax/ECPIL membrane for at least 100 h.Overall,this work not only illustrates that PILs with ether-rich and carboxylate hydrogen bonding sites are outstanding materials for simultaneous removal of H_(2)S and CO_(2),but may also provide a novel insight into the design of membrane materials for natural gas upgrading.
文摘Cell membranes play a crucial role in many biological functions of cells. A small change in the composition of cell membranes can strongly influence the functions of membrane-associated proteins, such as ion and water channels, and thus mediate the chemical and physical balance in cells. Such composition change could originate from the introduction of short-chain alcohols, or other anesthetics into membranes. In this work, we have applied sum frequency generation vibrational spectroscopy （SFG-VS）, supplemented by attenuated total reflectance Fourier transform infrared spectroscopy （ATR-FTIR）, to investigate interaction between methanol and 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine （d54-DMPC） lipid bilayers. Lipid＇s hydrocarbon interior is deuterated while its head group is hydrogenated. At the same time, CH3 symmetric stretch from methanol and lipid head amine group has different frequency, thus we can distinguish the behaviors of methanol, lipid head amine group, and lipid hydrocarbon interior. Based on the spectral feature of the bending mode of the water molecules replaced by methanol, we determined that the methanol molecules are intercalated into the region between amine and phosphate groups at the lipid hydrophilic head. The dipole of CH3 groups of methanol and lipid head, and the water O-H M1 adopt the same orientation directions. The introduction of methanol into the lipid hydrophilic head group can strongly perturb the entire length of the alkyl chains, resulting that the signals of CD2 and CD3 groups from both leaflets can not cancel each other.
文摘Motivated by recent experimental observations that carbon nanotubes （CNT） can enter animal cells, here we conduct coarse grained molecular dynamics and theoretical studies of the intrinsic interaction mechanisms between CNT＇s and lipid bilayer. The results indicate that CNT-cell interaction is dominated by van der Waals and hydrophobic forces, and that CNT＇s with sufficiently small radii can directly pierce through cell membrane while larger tubes tend to enter cell via a wrapping mechanism. Theoretical models are proposed to explain the observed size effect in transition of entry mechanisms.
文摘A series of sulfonated polyimide copolymers as novel proton exchange materials were synthesized by the polycondensation of 1,4,5,8-naphthalene-tetracarboxylic dianhydride （NTDA）, sulfonated diamine based on pyridine group and diamine containing N-phenyl-1,2,4-triazole moiety. Flexible, transparent and tough membranes with high thermal stability and good mechanical properties were obtained. They exhibited good stability in boiling water and Fenton＇s reagent at 80 ℃. More interestingly, a nonlinear relationship between proton conductivities of the resulting membranes and the degree of sulfonation （DS） was observed. The membrane with 50% DS exhibited the maximum proton conductivity, which was due to the combinational contributions of sulfonic acid and N-pheny-1,2,4-triazole groups. Thus, the N-phenyl-l,2,4- triazole moiety in this study not only can depress water absorption but also increase proton conductivity, especially at low DS.
文摘Aim： To investigate the possible functions of human sperm membrane protein （hSMP-1） in the process of fertilization. Methods： A 576-bp cDNA fragment of HSD-1 gene coding for the extracellular domain of hSMP-1 was cloned and expressed. The localization of this protein on human and mouse sperm was determined by indirect immunofluorescent staining by using anti-recombinant hSMP-1 （anti-rhSMP-1） antibodies. Sperm acrosome reaction and spermzona pellucida （ZP） binding assay were carried out in 10-week-old BALB/c mice. Results： Recombinant hSMP-1 was successfully cloned and expressed. The expression of the native protein was limited on the acrosome of human and mouse sperm. Treatment of anti-rhSMP-1 antibodies significantly decreased the average number of sperms bound to each egg. Meanwhile, the percentage of acrosome reaction was decreased in comparison to pre-immune control after treatment with anti-rhSMP-1 （P 〈 0.05）. Conclusion： The results suggest that anti-rhSMP-1 antibody inhibited mouse acrosome reaction and sperm-ZP binding.
文摘A novel capillary electrophoresis method coupled with on-line microdialysis using an attachable electrode has been developed to study the interaction of macromolecule with small molecule. The binding constants of bovine serum album (BSA) with D,L-tryptophan (Trp), sulfamethoxazole (SMZ) with trypsin and chymotrypsin were determined. These values are 2.3 x 10(4)L/mol for BSA-L-Trp; 1.77 x 10(3) L/mol for BSA-D-Trp in pH 7.4, 50 mmol/ L phosphate; 1.4 x 10(4) L/mol for SMZ- trypsin and 6.0 x 10(3) L/mol for SMZ-chymotrypsin in pH 6.5, 25 mmol/L Tris buffer. The proposed method has merits of speed, low sample consumption and readily available to be performed in desired physiological conditions.
基金National Taiwan University Core Consortium,No.NTU-CC-110L892501Ministry of Science and Technology,No.MOST 110-2218-E-002-037.
文摘BACKGROUND The therapeutic potential of mesenchymal stem cells(MSCs)in the form of threedimensional spheroids has been extensively demonstrated.The underlying mechanisms for the altered cellular behavior of spheroids have also been investigated.Cell membrane fluidity is a critically important physical property for the regulation of cell behavior,but it has not been studied for the spheroid-forming cells to date.AIM To explore the association between cell membrane fluidity and the morphological changes of MSC spheroids on the surface of biomaterials to elucidate the role of membrane fluidity during the spheroid-forming process of MSCs.METHODS We generated three-dimensional(3D)MSC spheroids on the surface of various culture substrates including chitosan(CS),CS-hyaluronan(CS-HA),and polyvinyl alcohol(PVA)substrates.The cell membrane fluidity and cell morphological change were examined by a time-lapse recording system as well as a highresolution 3D cellular image explorer.MSCs and normal/cancer cells were prestained with fluorescent dyes and co-cultured on the biomaterials to investigate the exchange of cell membrane during the formation of heterogeneous cellular spheroids.RESULTS We discovered that vesicle-like bubbles randomly appeared on the outer layer of MSC spheroids cultured on different biomaterial surfaces.The average diameter of the vesicle-like bubbles of MSC spheroids on CS-HA at 37℃ was approximately 10μm,smaller than that on PVA substrates(approximately 27μm).Based on time-lapse images,these unique bubbles originated from the dynamic movement of the cell membrane during spheroid formation,which indicated an increment of membrane fluidity for MSCs cultured on these substrates.Moreover,the membrane interaction in two different types of cells with similar membrane fluidity may further induce a higher level of membrane translocation during the formation of heterogeneous spheroids.CONCLUSION Changes in cell membrane fluidity may be a novel path to elucidate the complicated physiological alterations in 3D spheroid-forming cells.
文摘Metyrapone (2-methyl-1,2-di-3-pyridyl-1-propanone) is a drug largely used as inhibitor of glucocorticoid synthesis. Although its binding to various proteins has been well indentified, its accurate molecular mechanism of action remains unknown. Therefore, the interactions of metyrapone (MET) with various membrane components such as phospholipids, cholesterol, their corresponding polar heads and a model serine containing peptide have been investigated by NMR and ESR methods. It was found that neither cholesterol nor most of the phospholipids tested, nor dimyristin exhibit any interaction with MET, except phosphatidylserine (DMPS). Furthermore, only serine bearing polar head (O-phosphoserine) showed an association with MET (stoechiometry 1:1, Kd = 3200M-1). As similar observations were also performed on serine alone and in the presence of the serine containing model peptide, (NASDSDGQDL), a possible implication of these interactions in the binding recognition of MET on serine-containing active site was finally tested and discussed.
基金supported by the National Natural Science Foundation of China(32150410366,31972338,and32372639)the earmarked fund for China Agriculture Research System(CARS-02-26)+1 种基金the National Key Research and Development Program of China(2021YFD1400700)the Special Grant of China Postdoctoral Science Foundation(2022T150712)。
文摘The mirid bug Apolygus lucorum(Hemiptera:Miridae)is a polyphagous pest that affects a wide range of host plants.Its control remains challenging mainly due to its rapid reproduction,necessitating an understanding of sex pheromone communication.The recognition of sex pheromones is vital for courtship and mating behaviors,and is mediated by various chemosensory-associated proteins.Among these,sensory neuron membrane protein(SNMP),a CD36-related protein,is suggested to play crucial roles in detecting sex pheromones.In this study,we employed transcriptomic and genomic data from A.lucorum and phylogenetic approaches,and identified four putative SNMP genes(AlucSNMP1a,AlucSNMP1b,AlucSNMP2a,and AlucSNMP2b)with full open reading frames.Expression analysis revealed the ubiquitous presence of AlucSNMP transcripts in multiple tissues,with only AlucSNMP1a exhibiting male-biased expression in the antennae,suggesting its potential role in male chemosensation.Functional analysis using the Xenopus oocyte expression system,coupled with two-electrode voltage clamp recording,demonstrated that the co-expression of AlucSNMP1a with specific pheromone receptors(PRs)and the Odorant receptor co-receptor(Orco)significantly enhanced electrophysiological responses to sex pheromones compared to the co-expression of PRs and Orco alone.Moreover,the results indicated that the presence of AlucSNMP1a not only affected the responsiveness to sex pheromones but also influenced the kinetics(activation and inactivation)of the induced signals.In contrast,the co-expression of AlucSNMP1b with AlucPR/Orco complexes had no impact on the inward currents induced by two pheromone compounds.An examination of the selective pressures on SNMP1 genes across 20 species indicated strong purifying selection,implying potential functional conservation in various insects.These findings highlight the crucial role of AlucSNMP1a in the response to sex pheromones.
文摘Carbon monoxide releasing molecules (CORMs) have been recently developed for research and pharmacological purposes. A considerable amount of studies demonstrated a wide spectrum of biological activities for lipophilic CORM-2 (tricarbonyldichlororuthenium (II) dimer). It is generally accepted that the liberated gas provides the specific activities to CORMs, with a little attention paid to any possible effect of complementary core molecules. However, the versatile repertoire of actions attributed to CORM-2 is surprisingly wide for CO, a molecule with the sole chemical activity of binding to ferrous iron in protein prosthetic groups. The study was designed to analyze CORM-2 and its core molecule (“i”CORM) activities at a molecular level. With respect to the hydrophobic nature of the compounds, we followed their interactions with several amphipathic entities: the heme sites of hemoproteins, heme binding proteins and cell membranes. CORM-2/“i”CORM decreased the Soret optical density of hemoglobin and myoglobin, indicating that both compounds interact with the protein amphipathic site in the heme pocket. Pre-addition of CORM-2/“i”CORM to the apo-forms of the plasma heme binding proteins, hemopexin and albumin, partially abolished their heme binding capacity. In contrast, the compounds had no effect on the preformed heme-protein complexes. Addition of CORM-2/“i”- CORM to blood or isolated erythrocytes revealed aggregation of the cells or lysis, depending on the rea-gent-to-cells ratio. It was concluded that the ruthenium containing core molecule of CORM-2 may be physiologically active due to non-specific hydrophobic interactions. As each type of CORMs is expected to have a different mode of action beyond CO activity, their potential therapeutic uses will require clarification.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)(No.BR 1511/12-1)。
文摘Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight characteristics.The investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting surface.The focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type gust.At a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction simulations.First,the numerical results are validated by experimental data from force and moment,flow field,and deformation measurements.Second,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic membrane.For all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical results.During the decay of the gust,they differ more the higher the aspect ratio of the wing.When considering the flow field,the main differences are due to the separation behavior on the upper side of the wing.The flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the former.Only at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.
