Permeability and selectivity synergistically enhanced nanofluidic membrane for osmotic energy harvesting

For the porous‐membrane‐based osmotic energy generator,the potential synergistic enhancement mechanism of various key parameters is still controversial,especially because optimizing the trade‐off between permeability and selectivity is still a challenge.Here,to construct a permeability and selectivity synergistically enhanced osmotic energy generator,the twodimensional porous membranes with tunable charge density are prepared by inserting sulfonated polyether sulfone into graphene oxide.Influences of charge density and pore size on the ion transport are explored,and the ionic behaviors in the channel are calculated by numerical simulations.The mechanism of ion transport in the process is studied in depth,and the fundamental principles of energy conversion are revealed.The results demonstrate that charge density and pore size should be matched to construct the optimal ion channel.This collaborative enhancement strategy of permeability and selectivity has significantly improved the output power in osmotic energy generation;compared to the pure graphene oxide membrane,the composite membrane presents almost 20 times improvement.

A Single-chain Antibody for One-pot Fabrication of Luminescent Gold Nanoclusters and Rabies Virus Imaging in Cells

The fragile antibody leads to a great challenge as a scaffold to fabricate the luminescent metal nanoclusters using one-pot method.This study presents a stable single-chain anti-body(scFv57R-ATS)for the fabrication of luminescent gold nanoclusters(AuNCs@scFv57R-ATS)and a quick,sensitive rabies virus detection in living cells.In this paper,AuNCs@scFv57R-ATS was designed to specifically recognize antigen RV in modified HeLa cells,which promoted the demonstration of metal nanocluster fluorescent probes for antigen targeting and therapy.

Identification,structure elucidation and origin of a common pyridinium-thiocyanate intermediate in electrospray mass spectrometry among the benziamidazole-class proton pump inhibitors

During the analysis of benziamidazole-class irreversible proton pump inhibitors,an unusual mass spectral response with the mass-to-charge ratio at[Mt10]t intrigued us,as it couldn't be assigned to any literature known relevant structure,intermediate or adduct ion.Moreover,this mysterious mass pattern of[Mt10]t has been gradually observed by series of marketed proton pump inhibitors,viz.omeprazole,pantoprazole,lansoprazole and rabeprazole.All the previous attempts to isolate the corresponding component were unsuccessful.The investigation of present work addresses this kind of signal to a pyridinium thiocyanate mass spectral intermediate(10),which is the common fragment ion of series of labile aggregates.The origin of such aggregates can be traced to the reactive intermediates formed by acid-promoted degradation.These reactive intermediates tend to react with each other and give raise series of complicated aggregates systematically in a water/acetonitrile solution by electrospray ionization.The structure of the corresponding pyridinium thiocyanate species of omeprazole(10a)has been eventually characterized with the help of synthetic specimen(10a′).Our structural proposal as well as its origin was supported by in situ nuclear magnetic resonance,chemical derivatization and colorimetric experiments.

Hydrothermal Synthesis and Characterization of a Novel Supramolecular Network Compound [Co(IN)_2(H_2O)_4](IN=Isonicotinate)

A novel supramolecular compound, [Co(IN)_2(H_2O)_4](1), was synthesized by means of the hydrothermal method and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffraction. Though the unit cell structure of the title compound is only monomeric, all these units as building blocks are assembled into a novel three-dimensional supramolecular network via the widely hydrogen-bonding and π-π stacking interactions.

Electronic modulation and interface engineering of electrospun nanomaterials‐based electrocatalysts toward water splitting

Nowdays,electrocatalytic water splitting has been regarded as one of the most efficient means to approach the urgent energy crisis and environmental issues.However,to speed up the electrocatalytic conversion efficiency of their half reactions including hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),electrocatalysts are usually essential to reduce their kinetic energy barriers.Electrospun nanomaterials possess a unique one‐dimensional structure for outstanding electron and mass transportation,large specific surface area,and the possibilities of flexibility with the porous feature,which are good candidates as efficient electrocatalysts for water splitting.In this review,we focus on the recent research progress on the electrospun nanomaterials‐based electrocatalysts for HER,OER,and overall water splitting reaction.Specifically,the insights of the influence of the electronic modulation and interface engineering of these electrocatalysts on their electrocatalytic activities will be deeply discussed and highlighted.Furthermore,the challenges and development opportunities of the electrospun nanomaterials‐based electrocatalysts for water splitting are featured.Based on the achievements of the significantly enhanced performance from the electronic modulation and interface engineering of these electrocatalysts,full utilization of these materials for practical energy conversion is anticipated.

Synthesis, Crystal, Calculated Structure and Biological Activity of N-((6-bromo-2-methoxyquinolin-3-yl)(phenyl) methyl)-N-(1-adamantyl)-3-(dimethylamino) Propanamide

The halogenated hydrocarbon amination reaction between the original raw material N-（（6-bromo-2-methoxyquinolin-3-yl）（phenyl）methyl）-3-chloro-N-（1-adamantyl） propanamide and dimethylamine hydrochloride produces the target molecule N-（（6-bromo-2-methoxyquinolin-3- yl）（phenyl）methyl）-N-（1-adamantyl）-3-（dimethylamino） propanamide （C32H38BrN3O2, Mr = 576.56）, and its structure was confirmed by elemental analysis, IR, 1H NMR, MS, and X-ray diffraction. This crystal is of monoclinic system, space group P21/c with a = 10.760（5）, b = 14.768（5）, c = 19.635（5）, β = 113.969（16）°, V = 2851.0（18）3, Z = 4, Dc = 1.343 g/cm3, F（000） = 1208, μ（MoKα） = 1.475 mm-1, the final R = 0.0645 and wR = 0.2039. In total, 4681 independent reflections including 3164 observed ones with I 〉 2σ（I） were collected. The dihedral angle between substituted quinolyl and phenyl is 64.0°. Through C-H···O, C-H···N and C-H···Br weak hydrogen bonds among molecules, the whole molecule is stacked into a three-dimensional structure. The optimized geometric bond lengths and bond angles obtained by using density functional theory （DFT） have been compared with X-ray diffraction values. In addition, the preliminary biological test showed that the title compound has anti-Mycobacterium phlei 1180 activity.

Carbon dots-derived carbon nanoflowers decorated with cobalt single atoms and nanoparticles as efficient electrocatalysts for oxygen reduction

The sluggish kinetics of oxygen reduction reaction(ORR)hinders the commercialization of Zn‐air batteries(ZABs).Manipulating the electronic structure of electrocatalysts to optimize the adsorption energy of oxygen‐containing intermediates during the 4e–ORR offers a practical route toward improving ORR kinetics.Herein,we designed a novel ORR electrocatalyst containing Co single atoms and nanoparticles supported by carbon dots‐derived carbon nanoflowers(Co SAs/NPs CNF).Co SAs/NPs CNF possessed a very high ORR activity(E_(1/2) of the Co SAs/NPs CNF catalyst is 0.83 V(vs.RHE)),and outstanding catalytic performance and stability when used as the air‐electrode catalyst in rechargeable ZABs(152.32 mW cm^(-2),1000.58 mWh gZn^(–1),and over 1300 cycles at a current density of 5 mA cm^(-2)).The Co SAs and Co NPs cooperated to improve electron and proton transfer processes during ORR.Theoretical calculations revealed that the presence of adjacent Co NPs optimized the electronic structure of the isolated Co‐N_(4) sites,significantly lowering the energy barriers for the rate‐determining step in ORR(adsorption of*OOH)and thereby delivering outstanding ORR performance.This work reveals that the combination of supported single‐atom sites and metal nanoparticles can be highly beneficial for ORR electrocatalysis,outperforming catalysts containing only Co SAs or Co NPs.

Mechanism of Surface-Enhanced Raman Scattering and Its Application to Highly Sensitive Protein Detection

Surface-enhanced resonance Raman scattering(SERRS)has recently attracted great interest in analytical science due toenormous enhancement factors that have decreased the detec-tionli mits of a wide variety of molecules to the single moleculelevel.The SERRS-electromagnetic(EM)model describessingle-molecule SERRS

Raman and Surface-enhanced Raman Scattering of Chlorophenols

Raman spectrum is a powerful analytical tool for determining the chemical information of compounds. In this study, we obtained analytical results of chlorophenols（CPs） molecules including 4-chlorophenol（4-CP）, 2,6-dich- lorophenol（2,6-DCP） and 2,4,6-trichlorophenol（2,4,6-TCP） on the surface of Ag dendrites by surface-enhanced Raman scattering（SERS） spectra. SEM images indicate that the SERS substrate of Ag dendrites is composed of a large number of polygonal nanocrystallites, which self-assembled into a 3D hierarchical structure. It was found that there were distinct differences for those three molecules from Raman and SERS spectra. This indicates that SERS could be a new tool of detection technique regarding trace amounts of CPs.

Construction of hollow polydopamine nanoparticle based drug sustainable release system and its application in bone regeneration

Nanomaterial-based drug sustainable release systems have been tentatively applied to bone regeneration.They,however,still face disadvantages of high toxicity,low biocompatibility,and low drug-load capacity.In view of the low toxicity and high biocompatibility of polymer nanomaterials and the excellent load capacity of hollow nanomaterials with high specific surface area,we evaluated the hollow polydopamine nanoparticles(HPDA NPs),in order to find an optimal system to effectively deliver the osteogenic drugs to improve treatment of bone defect.Data demonstrated that the HPDA NPs synthesized herein could efficiently load four types of osteogenic drugs and the drugs can effectively release from the HPDA NPs for a relatively longer time in vitro and in vivo with low toxicity and high biocompatibility.Results of qRT-PCR,ALP,and alizarin red S staining showed that drugs released from the HPDA NPs could promote osteogenic differentiation and proliferation of rat bone marrow mesenchymal stem cells(rBMSCs)in vitro.Image data from micro-CT and H&E staining showed that all four osteogenic drugs released from the HPDA NPs effectively promoted bone regeneration in the defect of tooth extraction fossa in vivo,especially tacrolimus.These results suggest that the HPDA NPs,the biodegradable hollow polymer nanoparticles with high drug load rate and sustainable release ability,have good prospect to treat the bone defect in future clinical practice.

6,8-Di-tert-butyl-3-(2,4-dimethyl-quinolin-7-yl)-3,4-dihydro-2H-benzo[e][1,3]oxazine: Synthesis, Crystal Structure and Luminescent Properties

6,8-Di-tert-butyl-3-（2,4-dimethyl-quinolin-7-yl）-3,4-dihydro-2H-benzo[e][1,3]oxa- zine（1） was obtained by one-pot reaction starting from 2,4-di-tert-butylphenol, 7-amino-2,4- dimethyl-quinoline and paraformaldehyde. The compound was structurally characterized by NMR, IR and single-crystal X-ray diffraction along with the elemental analysis. Compound 1 crystallizes as solvate with chloroform. The solvate 1·CHCl3（C28 H35 Cl3 N2 O, Mr = 521.93） belongs to the triclinic system, space group P1 with a = 10.852（2）, b = 11.352（2）, c = 13.050（3）, α = 101.95（3）, β = 92.94（3）, γ = 114.64（3）o, V = 1412.4（5）3, Z = 2, Dc = 1.227 g/cm3, F（000） = 552, μ = 0.347 mm–1, R = 0.0959 and wR = 0.2725（I 〉 2？（I））. The chloroform molecule displays a rotational disorder as one chloro atom can be located at two different positions. The packing of 1·CHCl3 was further stabilized by intramolecular C–H…O interactions, intermolecular C–H…N interactions, C–H…π interactions, and π…nteractions. The luminescent properties of compound 1 in both methylene chloride solution and the solid state were studied.

Responses of Transmembrane Peptide and Lipid Chains to Hydrophobic Mismatch

Hydrophobic mismatch between the hydrophobic length of membrane proteins and hydrophobic thickness of membranes is a crucial factor in controlling protein function and assembly.We combined fluorescence with circular dichroism（CD） and attenuated total reflection infrared（ATR-IR） spectroscopic methods to investigate the behaviors of the peptide and lipids under hydrophobic mismatch using a model peptide from the fourth transmembrane domain of natural resistance-associated macrophage protein 1（Nramp1）,the phosphatidylcholines（PCs） and phosphatidylglycerols（PGs） with different lengths of acyl chains（14：0,16：0 and 18：0）.In all PG lipid membranes,the peptide forms stable α-helix structure,and the helix axis is parallel to lipid chains.The helical span and orientation hardly change in varying thickness of PG membranes,while the lipid chains can deform to accommodate to the hydrophobic surface of embedded peptide.By comparison,the helical structures of the model peptide in PC lipid membranes are less stable.Upon incorporation with PC lipid membranes,the peptide can deform itself to accommodate to the hydrophobic thickness of lipid membranes in response to hydrophobic mismatch.In addition,hydrophobic mismatch can increase the aggregation propensity of the peptide in both PC and PG lipid membranes and the peptide in PC membranes has more aggregation tendency than that in PG membranes.

A Method for Directly Counting and Quantitatively Comparing Aggregated Structures during Cluster Formation

Assembling of a few particles into a cluster commonly occurs in many systems.However,it is still challenging to precisely control particle assembling,due to the various amorphous structures induced by thermal fluctuations during cluster formation.Although these structures may have very different degrees of aggregation,a quantitative method is lacking to describe them,and how these structures evolve remains unclear.Therefore a significant step towards precise control of particle self-assembly is to describe and analyze various aggregation structures during cluster formation quantitatively.In this work,we are motivated to propose a method to directly count and quantitatively compare different aggregated structures.We also present several case studies to evaluate how the aggregated structures during cluster formation are affected by external controlling factors,e.g.,different interaction ranges,interaction strengths,or anisotropy of attraction.

Effect of intramolecular and intermolecular hydrogen bonding on the ESIPT process in DEAHB molecule

Density functional theory（DFT） and time-dependent density functional theory（TDDFT） methods are used to investigate the influences of intramolecular and intermolecular hydrogen bonding on excited-state intramolecular proton transfer（ESIPT） for the 4-N,N-（diethylamino）-2-hydroxybenzaldehyde（DEAHB）. The structures of DEAHB and its hydrogenbonded complex in the ground-state and the excited-state are optimized. In addition, the detailed descriptions of frontier molecular orbitals of the DEAHB monomer and DEAHB-DMSO complex are presented. Moreover, the transition density matrix is worked out to gain deeper insight into the orbitals change. It is hoped that the present work not only elaborates different influence mechanisms between intramolecular and intermolecular hydrogen bonding interactions on the ESIPT process for DEAHB, but also may be helpful to design and develop new materials and applications involved DEAHB systems in the future.

Accurate treatments of electrostatics for computer simulations of biological systems: A brief survey of developments and existing problems

Modern computer simulations of biological systems often involve an explicit treatment of the complex interactions among a large number of molecules. While it is straightforward to compute the short-ranged Van der Waals interaction in classical molecular dynamics simulations, it has been a long-lasting issue to develop accurate methods for the longranged Coulomb interaction. In this short review, we discuss three types of methodologies for the accurate treatment of electrostatics in simulations of explicit molecules： truncation-type methods, Ewald-type methods, and mean-field-type methods. Throughout the discussion, we brief the formulations and developments of these methods, emphasize the intrinsic connections among the three types of methods, and focus on the existing problems which are often associated with the boundary conditions of electrostatics. This brief survey is summarized with a short perspective on future trends along the method developments and applications in the field of biological simulations.

Characterization of Nanostructures in Acellular Cementum of Human Tooth Roots

Determining the microstructure in human cementum might help us design new kinds of replacement materials for the treatment of teeth injury and disease. The authors characterized the nanostructures in the cementum of health human teeth via scanning electronic microscopy（SEM）. It was found that the acellular cementum is mainly composed of two kinds of nanostructures―inorganic nanoparticles and organic nanofibers. And the inorganic nanoparticles show a tendency to arrange along the organic nanofibers. Based on the micro-molding in capillary strategy, the distribution of organic component in acellular cementum was copied with UV curable resin. After removing the inorganic nanoparticles by acid etching, many isolated spindle shape nanopores were left in polymer, which su- ggested that the inorganic nanoparticles should have been isolated by the organic component in cementum, and should be oval or nanosheet in shape. We hope the present work could provide reference for the biomimetic preparation of tissue engineering materials, and help us design new types of tooth implant.

Investigation of fluorescence resonance energy transfer ultrafast dynamics in electrostatically repulsed and attracted exciton-plasmon systems

Following the gradual maturation of synthetic techniques for nanomaterials,exciton-plasmon composites have become a research hot-spot due to their controllable energy transfer through electromagnetic fields on the nanoscale.However,most reports ignore fluorescence resonance energy transfer(FRET)under electrostatic repulsion conditions.In this study,the FRET process is investigated in both electrostatic attraction and electrostatic repulsion systems.By changing the Au:quantum dot ratio,local-field induced FRET can be observed with a lifetime of ns and a fast component of hundreds of ps.These results indicate that the intrinsic transfer process can only elucidated by considering both steady and transient state information.

Synthesis of stimuli-responsive pillararene-based supramolecular polymer materials for the detection and separation of metal ions

A stimuli-responsive supramolecular polymer network(G-(CN)_(2)⊂BXDSP5)with aggregation-induced emission(AIE)properties has been efficiently constructed by host-guest interactions between pillar[5]arene derivative BXDSP5 and a homoditopic guest G-(CN)_(2),which shows not only excellent fluorescence properties due to the AIE effect but also desirable ion-sensing abilities in both solution and solid states,holding great potential in the applicable fluorescence detection for Fe^(3+).The resultant G-(CN)_(2)⊂BXDSP5 can be transformed into supramolecular polymer gel at high concentration via multiple noncovalent interactions,showing multi-stimuli-responsiveness in response to temperature change,mechanical force,and competitive agent.Meanwhile,the xerogel of supramolecular polymer material has been successfully used to remove Fe^(3+)from water with high adsorption efficiency.In addition,an ionresponsive film based on supramolecular polymer has also been developed,which can serve as a practical and convenient fluorescence test kit for detecting Fe^(3+).

Spontaneous Polymerization of An Amino Acid Based Amphiphile at Air/water Interface Investigated by ESI-MS and Transmission IR Spectrometry

Self-assemblies of amphiphilic molecules are proposed to play a ubiquitous role at the early stages of evolution in the formation of primitive biopolymers.[1]As regard to the significance of N-phosphoryl amino acids as a model for the co-evolution of protein and nucleic acids at the prebiotic stage,[2]amphiphilic N-phosphoryl amino acids with two hydrophobic tails were synthesized.

Construction of metallo-complexes with 2,2′:6′,2″-terpyridine substituted triphenylamine in different modified positions and their photophysical properties

The stable coordinated metallo-complexes based on 2,2′:6′,2″-terpyridine(tpy)and its derivatives have been widely researched for various wide-ranging applications in photoelectronics,catalysis,sensor,photoluminescence,and so on.However,the most reported studies ignored the comprehensive comparison between structures modified by different positions and photoluminescence.Herein,we design a series of metallo-complexes which were assembled with tpy substituted triphenylamine(TPA)at different positions and metal ions and explored their photophysical properties.In the solution state,MLE_(2)based on the 5,5″-positions modification showed the highest PLQYs and PL intensity.With the increase of solvent polarity,MLB2exhibit the largest redshift.In the solid state,from MLA_(2)to MLE_(2),the emission colours are gradually red-shifted from yellow to red.The findings in this work may pave a new way to design functional metallo-complexes,not just for PL properties.