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Ga-doped La5Ti2Cu0.9Ag0.1O7S5 absorbs visible light up to 710 nm and can serve as a H2 evolution photocatalyst in Z-scheme water splitting systems. This material is typically obtained in the form of rod-like particles that exhibit one-dimensional conductivity along their long axis. However, these relatively long particles (10–20 µm) require charge carriers migrate over significant distances to participate in photocatalytic reactions, which limits reaction efficiency. In the present study, Ga-doped La5Ti2Cu0.9Ag0.1O7S5 particles approximately 2 µm in length were prepared by thermal sulfidation. The as-formed particles had rod-like morphology but contained a lot of burrs that could be eliminated by annealing in the presence of sulfur vapor. Rh cocatalyst particles could be deposited on the tips of these particles in a dense, widely dispersed manner by stepwise impregnation-reduction and post-photodeposition. These treatments enhanced the photocatalytic H2 evolution activity of the Ga-doped La5Ti2Cu0.9Ag0.1O7S5 particles in aqueous solutions containing electron donors by a factor of seven and increased the apparent quantum efficiency of the process to 3.1% at 420 nm. This work demonstrates that thermal sulfidation is an effective approach to reducing the particle size of an oxysulfide photocatalyst. With appropriate post-treatment and cocatalyst loading processes, such photocatalysts can efficiently evolve hydrogen from aqueous solutions.

In this study, a novel TiC0.5-Al2O3/Cu composite was successfully prepared by spark plasma sintering using a mixture of the Ti2AlC, Cu2O and Cu powders as starting materials. The micron-sized Ti2AlC particles were decomposed into the submicron TiC0.5 grains during the sintering process. Further, Al atoms diffusing out of Ti2AlC entered Cu matrix and subsequently reacted with Cu2O to form Al2O3 grains. Due to the distribution of the submicron TiC0.5 and Al2O3 grains in the Cu matrix, the hardness increased on enhancing Ti2AlC content from 1 to 5 wt%, however, the electrical conductivity was observed to decrease. TiC0.5 and Al2O3 particles significantly improved the compression properties, and the ductility was maintained at a comparatively high level. On enhancing Ti2AlC content from 1-5 wt%, the yield strength of the material (σ0.2) increased from 118 MPa to 241 MPa, and the composite remained intact even after 25% strain.

Small-signal stability of three-phase grid-connected converters can be analysed by using the impedance-based method in d-q frame. Based on this approach, the d-q impedance models of both source and load subsystems are represented with 2-by-2 matrices, and their ratio (known as the return ratio matrix) is used for stability assessment. This, however, requires to apply the generalized Nyquist criterion (GNC), due to the intrinsic multi-input multi-output (MIMO) property of the d-q system. During the process, some complexities are inevitably caused because of the need to calculate the ratio of the impedance matrices, and to obtain the eigenvalues of the return ratio matrix. In this context, this paper presents an equivalent single-input single-output (SISO) model for the d-q impedance of three-phase grid-connected converters, which leads to two scalar impedance ratios of d- and q-axis, instead of the conventional 2-by-2 return ratio matrix. Consequently, the stability of the two SISO systems can be analysed by using the classic Nyquist stability criterion (NC), resulting in a much simpler and more intuitive analysis process than GNC. The equivalence between the original MIMO d-q impedance model and the proposed SISO model in stability assessment is verified by comparing their stability conditions. As an example of applying this approach, the effects of PLL, grid impedance, and power control on a grid-connected converter are investigated. The performed analysis is finally validated by Matlab/Simulink simulations.

It is well documented that placing a plasmonic antenna close to catalytically active nanoparticles can enhance their catalytic activity in chemical reactions via the near-field enhancement effect. Less known is whether and how the near-field enhances the reactivity of the reactant substrates involved in these reactions. Herein, we prepared an “antenna-reactor” catalyst with Au nanoparticles absorbing light as an optical antenna and the adjacent Pd nanoparticles acting as a chemical reactor to study the near-field enhancement effect in Suzuki–Miyaura cross-coupling reaction involving various substrates. The results showed that the activity of Pd nanoparticles were significantly enhanced in the presence of Au antennas. Excessively increasing the density of Au antennas, however, suppressed the reaction due to the interaction between neighboring electromagnetic hot spots. Moreover, the near-field affected different substrates in different extents, enhancing more to reactions that involve substrates with higher electron cloud density at the reactive center. The overall effect of the near-field to the catalytic reactions was proved to be an integrated result of the effect of Au nanoparticle density and reactive center electron cloud density. This study provides enriched understanding for the near-field enhancement effect in photocatalytic reactions with various substrates, and deepened insights for new “antenna-reactor” photocatalyst design.

Helical architectures including artwork and monuments, such us the Trajan’s column from Rome, were constructed as early as in the year 113 while the assemblies and the self-organizations of biologi...

Supported Au catalysts are widely used for CO oxidation due to their extremely high activity, and the modification of a support structure is a crucial method to improve catalytic performance. Herein, we prepared gold catalysts supported on flaky TiO2 and on TiO2 hydrogenated at different temperatures (200, 400, and 600 °C). We found that the sample with the support pretreated in hydrogen at 600 °C (0.5Au/TiO2-H600) showed the greatest advantages in activity and stability over the sample with as-prepared TiO2 nanosheets (0.5Au/TiO2-UC). First, calcination at 600 °C changed the exposed surface of TiO2 from {001} to {101}, and gold nanoparticles (2-3 nm) were observed as highly reactive species on 0.5Au/TiO2-H600. Moreover, the increase of oxygen vacancies on the surface of 0.5Au/TiO2-H600 was conducive to oxygen activation and promoted the catalytic activity. Therefore, we emphasized the important role of the support and gave an effective method to improve the catalytic performance by regulating the support structure.

The highly-dispersed iron element decorated Ni foam was prepared by simple immersion in a ferric nitrate solution at room temperature without using acid etching, and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), EDAX spectrum (EDAX mapping) and Raman spectroscopy. The EDAX spectrum illustrated that iron element was highly-dispersed over the entire surface of nickel foam, and the Raman spectroscopy revealed that both Ni-O and Fe-O bonds were formed on the surface of the as-prepared electrode. Moreover, the iron element decorated Ni foam electrode can be used as non-enzymatic glucose sensor and it exhibits not only an ultra-wide linear concentration range of 1–18 mmol/L with an outstanding sensitivity of 1.0388 mA·mmol/(L·cm2), but also an excellent ability of stability and selectivity. Therefore, this work presents a simple yet effective approach to successfully modify Ni foam as non-enzymatic glucose sensor.

The effect of the two‐dimensional glycan display on glycan‐lectin recognition remains poorly understood despite the importance of these interactions in a plethora of cellular processes, in (patho)physiology, as well as its potential for advanced therapeutics. Faced with this challenge we utilized glycodendrimersomes, a type of synthetic vesicles whose membrane mimics the surface of a cell and offers a means to probe the carbohydrate biological activity. These single‐component vesicles were formed by the self‐assembly of sequence‐defined mannose‐Janus dendrimers, which serve as surrogates for glycolipids. Using atomic force microscopy and molecular modeling we demonstrated that even mannose, a monosaccharide, was capable of organizing the sugar moieties into periodic nanoarrays without the need of the formation of liquid‐ordered phases as assumed necessary for rafts. Kinetics studies of Concanavalin A binding revealed that those nanoarrays resulted in a new effective ligand yielding a ten‐fold increase in the kinetic and thermodynamic constant of association., Multivalent interactions mediated by the cellular glycocalix are ubiquitous in biological processes. We utilized glycodendrimersomes, a type of synthetic cell membrane mimic to probe the carbohydrate biological activity towards lectins. We demonstrated that mannose could organize the sugar moieties into periodic nanoarrays resulting in a new effective ligand yielding a ten‐fold increase in the kinetic and thermodynamic constant of association.

Plasmonic noble metal nanoparticles exhibit intense interactions with light but are inherently chemically unreactive. Alloying plasmonic gold with catalytic palladium forms a hybrid catalyst incorp...

Direct photoexcitation of metal nanoparticles (NPs) can induce selective chemical reactions that are difficult to achieve with thermal energy. Here, we report that visible-light photoexcitation on palladium (Pd) NPs shows distinct particle size dependence; small Pd NPs (sub-3.0-nanometer) with low Pd loading (0.5 wt%) as a catalyst achieved excellent yield (100%) for Heck reaction. This is because (1) the light absorption of small Pd particles is more intensive than that of large Pd particles even if the Pd loadings are similar, and (2) the chemisorption of the reactants on the small Pd particles is stronger. The chemical adsorption can result in the hybridization of adsorbate orbitals and metal electronic states, and the photon absorption may directly excite the hybridized electronic states driving the reactions. This highly efficient visible-light-driven Pd nanocatalyst with low precious metal loading represents a promising step towards efficient cost-effective photocatalysis that operates under real-world conditions.

The design of novel catalytic materials towards sustainable energy production and storage is important for tackling energy shortage and environmental issues. Here, we report the preparation of cobalt nanoparticles encapsulated by a nitrogen doped carbon nano-onion (Co-NCNO) and their applications in the oxygen reduction reaction (ORR) and lithium-ion batteries (LIBs). Co-NCNO was prepared by one-step carbonization using an imidazolium ionic liquid as the carbon and nitrogen source. An in situ transmission electron microscope (in situ TEM) was used for the real time investigation of the carbon nano-onion formation process during a heating process from 450 °C to 850 °C. When applied to the ORR, Co-NCNO-850 exhibited high activity with a half-wave potential of 767 mV in 0.1 M KOH solution and high structural stability. Density functional theory (DFT) simulation indicates that the cobalt enhances the adsorption of reaction intermediates on the nitrogen doped carbon surface. Furthermore, Co-NCNO-850 also exhibited excellent performance for LIBs with a specific capacity of 774 mA h g−1 at a current density of 0.5C after 500 cycles. The ionic liquid assisted synthesis of Co-NCNO opens a new avenue for the efficient fabrication of hybrid nano-catalysts for energy applications.

A high degree of cocatalyst dispersion and intimate contact with the photocatalyst are vital for improving the activity of narrow bandgap photocatalytic materials. In this work, the addition of a small number of Na ions to a Pt cocatalyst deposited on a semiconducting BaTaO2N photocatalyst (with an absorption edge of 650 nm) enhanced photocatalytic H2 evolution under visible light irradiation. The addition of Na ions to the Pt-loaded BaTaO2N (Pt/BaTaO2N) caused more efficient evolution of H2 than Na-free Pt/BaTaO2N during Z-scheme overall water splitting. These results should assist in the fabrication of photocatalysts modified with highly dispersed cocatalysts for efficient water splitting.

Y2Ti2O5S2 has an absorption edge wavelength of 640 nm and functions as a photocatalyst for overall water splitting under visible light. At present, this material is synthesized using a solid-state reaction that requires several days and generates particles tens of micrometers in size. The present work demonstrates an alternative synthesis method based on thermal sulfidation under a H2S flow to obtain smaller particles. Using this new process, a precursor mixture was converted into Y2Ti2O5S2 after several hours of heating at 1423 K, although the resulting material contained some Y2O2S and TiSx as impurities. The primary Y2Ti2O5S2 particles were plate-like and some exposed (001) facets as the basal plane, while the majority aggregated to form secondary particles 1–2 µm in size. After loading with Rh, or with either IrO2 or CoOx, this material was active during sacrificial photocatalytic H2 and O2 evolution reactions, respectively.

In the current study, heterostructured Ag@AgCl@AgI nanotubes were synthesized via an anion-exchange reaction between Ag@AgCl nanotubes and I− anions. Moreover, their photocatalytic performance towards the decontamination of dye contaminants were examined. These prepared photocatalysts were accordingly characterized using high-resolution scanning electron microscopy (HR-SEM), XRPD, XPS, field-emission transmission electron microscopy (FE-TEM), and photoluminescence (PL) spectroscopy. The structural identification analyses confirmed that the photocatalysts had nanotubular morphology. Compared to polyhedral Ag@AgI nanocomposites, the amalgamation of I− ions into the Ag@AgCl framework extraordinarily improved the photocatalytic performance. The synthesized Ag@AgCl@AgI nanotubes can also be reused due to their high stability. Under visible-light irradiation, >91.8% of Rhodamine B (RhB) was degraded within 45 min using the catalyst AI–2 (Cl−/I− = 1:1). The radical trap experiments indicated that the photodegradation of RhB was driven by the participation of superoxide radical and the action of holes. Due to the surface plasmon resonance effect, the photocatalyst AI–2 demonstrated higher photocatalytic performance, enhanced surface area and photoelectron transfer, which is also ascribed to its unique heterostructured configuration.

PurposeThe paper aims to build a new objective evaluation method of fabric pilling by combining an integrated image analysis technology with a deep learning algorithm.Design/methodology/approachSeries of image analysis techniques were adopted. First, a Fourier transform transformed images into the frequency domain. The optimal resolution matrix of an exponential high-pass filter was determined by combining the energy algorithm. Second, the multidimensional discrete wavelet transform determined the optimal division level. Third, the iterative threshold method was used to enhance images to obtain a complete and clear pilling ball images. Finally, the deep learning algorithm was adopted to train data from pilling ball images, and the pilling levels were classified according to the learning features.FindingsThe paper provides a new insight about how to objectively evaluate fabric pilling grades. Results of the experiment indicate that the proposed objective evaluation method can obtain clear and complete pilling information and the classification accuracy rate of the deep learning algorithm is 94.2%, whose structures are rectified linear unit (ReLU) activation function, four hidden layers, cross-entropy learning rules and the regularization method.Research limitations/implicationsBecause the methodology of the paper is based on woven fabric, the research study’s results may lack generalizability. Therefore, researchers are encouraged to test other kinds of fabric further, such as knitted and unwoven fabrics.Originality/valueCombined with a series of image analysis technology, the integrated method can effectively extract clear and complete pilling information from pilled fabrics. Pilling grades can be classified by the deep learning algorithm with learning pilling information.

In 1920, at age 39 and the peak of his professional carrier, one of the most distinguished organic chemists of his generation, Hermann Staudinger, claimed that natural and synthetic polymers are covalent macromolecules rather than colloidal aggregates. This idea initiated chain reactions supporting and dismissing the covalent macromolecular concept. The story of his 1953 Nobel Prize in Chemistry is reported here.

A signal-amplified mercury sensing biosensor with desired sensitivity was developed through firstly using the GFP mutant with fluorescence increasing response towards Hg2+ as the reporter module. The developed biosensor showed response for Hg2+ in a relatively wide range of 1–10,000 nmol/L, and the detection limit was improved one or two orders of magnitude in comparison with most metal-sensing biosensors in similar constructs. In addition, the biosensor could distinguish Hg2+ easily from multiple metal ions and displayed strong adaptability to extensive pH conditions (pH 4.0–10.0). More importantly, the developed biosensor was able to provide an initial assessment of Hg2+ spiked in the environmental water with the recoveries between 85.70% and 112.50%. The signal-amplified strategy performed by the modified reporter module will be widely applicable to many other whole-cell biosensors, meeting the practical requirements with sufficient sensing performance.

The Co(III)-catalyzed redox-neutral annulation of benzamides and acrylamides with vinylene carbonate for the synthesis of isoquinolinones and pyridinones has been developed. This protocol employing inexpensive Co(III) as the catalyst tolerated diverse functional groups and substitution patterns, affording the target products with good to excellent yields. The synthetic utility of this transformation was demonstrated by a three-step synthesis of gusanlung D, 8-oxopseudopalmatine, and oxopalmatine.

The catalytic performance of zeolites in industry can often be enhanced by modification with transition metals and Ni is one of the most widely used transition metals for the hydrogenation and dehydrogenation catalysts. In this work, the structure and acid properties of Ni-modified HAl-ZSM-12 zeolites were investigated by the dispersion corrected periodic density functional theory. The results indicate that single Ni atoms can reduce the H atoms in the zeolites into H2 molecule, whereas the Ni clusters like Ni2 cannot. The quantity of Bronsted acid sites may decrease after the modification with single Ni atoms; the Ni atoms in the zeolites are oxidized and work as strong Lewis acid sites, which may weaken the Lewis acidity of Al3+. After modification with Ni, the Ni-modified ZSM-12 displays greater ability to adsorb hydrogen molecules. The adsorbed hydrogen molecules are dissociated to negatively charged H atoms, which do not function as Bronsted acid sites. Due to the transfer of electron from the Ni atoms to the pre-adsorbed H atoms, as revealed by the adsorption energy of NH3, the pre-adsorption of hydrogen on the Ni-modified ZSM-12 zeolites can enhance the Lewis acidity.

A diastereoselectivity-controllable formal [3+2]-cycloaddition of arylvinyl oxirane 2,2-diesters with cyclic N-sulfonyl imines is developed, affording the corresponding tricyclic oxazolidine derivatives in moderate to excellent yields with excellent diastereoselectivities in the presence of palladium(0) or scandium(III) triflate. This protocol allows selective synthesis of diastereomers of tricyclic oxazolidine derivatives under switchable and mild conditions. Further transformations of the obtained products were conducted by removing ester groups and arylvinyl moieties.

Release of cargo molecules from cell-like nanocarriers can be achieved by chemical perturbations, including changes to pH and redox state and via optical modulation of membrane properties. However, little is known about the kinetics or products of vesicle breakdown due to limitations in real-time imaging at nanometer length scales. Using a library of 12 single-single type photocleavable amphiphilic Janus dendrimers, we developed a self-assembling light-responsive dendrimersome vesicle platform. A photocleavable ortho-nitrobenzyl inserted between the hydrophobic and hydrophilic dendrons of amphiphilic Janus dendrimers allowed for photocleavage and disassembly of their supramolecular assemblies. Distinct methods used to self-assemble amphiphilic Janus dendrimers produced either nanometer size small unilamellar vesicles or micron size giant multilamellar and onion-like dendrimersomes. In situ observation of giant photosensitive dendrimersomes via confocal microscopy elucidated rapid morphological transitions that accompany vesicle breakdown upon 405 nm laser illumination. Giant dendrimersomes displayed light-induced cleavage, disassembling and reassembling into much smaller vesicles at millisecond time scales. Additionally, photocleavable vesicles demonstrated rapid release of molecular and macromolecular cargos. These results guided our design of multilamellar particles to photorelease surface-attached proteins, photoinduce cargo recruitment, and photoconvert vesicle morphology. Real-time characterization of the breakdown and reassembly of lamellar structures provides insights on partial cargo retention and informs the design of versatile, optically regulated carriers for applications in nanoscience and synthetic biology.

The selective and quantitative detection of H2O2 is important for its employment in physiological, environmental and industrial applications. In this paper, a sensitive and selective strategy for H2O2 detection was established based on the fluorescence quenching of CdSe@ZnS quantum dots (QDs) by H2O2-mediated etching process of Ag nanoclusters (AgNCs). In this strategy, dihydrolipoic acid (DHLA) modified AgNCs were applied as H2O2 response group, the existence of H2O2 could initiate the oxidation of AgNCs and the production of Ag+. CdSe@ZnS QDs are very sensitive to Ag+, which could give rise to the effective fluorescence quenching of CdSe@ZnS QDs. Based on this strategy, the present fluorescent assay could realize the quantification detection of H2O2 and the limit of detection is calculated to be 0.3 μM under the optimum conditions. Furthermore, CdSe@ZnS/AgNCs hybrid-based probe was applied to detecting H2O2 in milk samples and showed a good recoveries results ranged from 95.8% to 112.0%, meaning the potential applicability of this strategy.

Mercury pollution has always been a huge threat to human health due to its significant toxicity. Thus, it's the continuing goal to obtain new mercury detection techniques that are cost-effective, operational stable, performance efficient, and applicable to the environmental and biological milieus. In this research, the soluble pigment pyocyanin with anti-bacterial and anti-fungal activities, the biosynthesis pathway of which was engineered under the regulation of Hg2+-dependent transcriptional activator MerR, was firstly used as the visual detection signal in the whole-cell biosensor. The engineered biosensor displayed optical sensing window and a good linearity for Hg2+ in the range of 25–1000 nM, and the detection limit could reach as low as 10 nM. It permitted on-site detection of bioavailable Hg2+ with extraordinary selectivity and could resist the interferences of extra metal ions. What's more, the developed biosensor performed function well in a wide pH range (pH 4–10) as well as the environmental water. By fully imitating and utilizing the biosystems from nature, the engineered colorimetric biosensor has great economic and performance advantages over most chemosensors as well as whole-cell biosensors in the practical application of detecting Hg2+ in the contaminated aquatic systems.

Antimonene is an emerging semiconducting two-dimensional (2D) material with various attractive properties, but its applications in optoelectronics have rarely been explored. Herein, we report a highly efficient preparation of few-layered antimonene by a polymer ionic liquid (PIL) assisted liquid-phase exfoliation method, which gives above 20% yield of micrometer sized nanosheets. Stability studies suggested that the presence of water in the solvent significantly accelerated the decomposition of the produced antimonene, while the antimonene dispersed in dry DMF exhibited a very high stability under ambient conditions. For the first time, flexible photodetectors based on a hybrid structure of few layer antimonene nanosheets modified by PIL and CdS quantum dots (QDs) were fabricated, which showed a good responsivity of 10 μA W−1 and on/off ratio of 26.8 under the bias of 1 V. This work demonstrates that PIL assisted liquid-phase exfoliation is a very promising method to achieve highly efficient preparation, preservation, and surface modification of few-layer antimonene, and hence enable the application of antimonene-based 2D materials in optoelectronics.

A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been synthesized. The terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the channel structures. The artificial channel could incorporate into the lipid bilayer efficiently under low concentration. The channel displays high NH4+/K+ selectivity due to the electrostatic interaction and hydrogen bonding between NH4+ and the terminal dihydrogen phosphate groups.

Development of high-performance dopant-free hole-transporting materials (HTMs) with comprehensive passivation effects is highly desirable for all-inorganic perovskite solar cells (PVSCs). Squaraines (SQs) could be a candidate for dopant-free HTMs as they are natural passivators for perovskites. One major limitation of SQs is their relatively low hole mobility. Herein we demonstrate that polymerizing SQs into pseudo two dimensional (2D) p-π conjugated polymers could overcome this problem. By rationally using N,N-diarylanilinosquaraines as the comonomers, the resulting polysquaraine HTMs not only exhibit suitable energy levels and efficient passivation effects, but also achieve very high hole mobility close to 0.01 cm-2 V-1 s-1 . Thus as dopant-free HTMs for α-CsPbI2 Br-based all-inorganic PVSCs, the best PCE reached is 15.5 %, outperforming those of the doped-Spiro-OMeTAD (14.4 %) based control devices and among the best for all-inorganic PVSCs.

Plasmonic metal NPs such as Au and Ag are proven to channel visible-light photon energy to nearby metal complexes effectively and allow the conventional metal cationic catalysts to work at moderate temperatures under light irradiation. A key finding is that reactant molecules can be significantly concentrated at the active sites simply by light and thus increase the chance of activation. The merging of plasmonic antenna and metal cationic catalysis will be an inspiring strategy for designing efficient photocatalytic systems.

The High Precision Magnetometer (HPM) is one of the main payloads onboard the China Seismo-Electromagnetic Satellite (CSES). The HPM consists of two Fluxgate Magnetometers (FGM) and the Coupled Dark State Magnetometer (CDSM), and measures the magnetic field from DC to 15 Hz. The FGMs measure the vector components of the magnetic field; while the CDSM detects the magnitude of the magnetic field with higher accuracy, which can be used to calibrate the linear parameters of the FGM. In this paper, brief descriptions of measurement principles and performances of the HPM, ground, and in-orbit calibration results of the FGMs are presented, including the thermal drift and magnetic interferences from the satellite. The HPM in-orbit vector data calibration includes two steps: sensor non-linearity corrections based on on-ground calibration and fluxgate linear parameter calibration based on the CDSM measurements. The calibration results show a reasonably good stability of the linear parameters over time. The difference between the field magnitude calculated from the calibrated FGM components and the magnitude directly measured by the CDSM is just 0.5 nT (1σ) when the linear parameters are fitted separately for the day- and the night-side. Satellite disturbances have been analyzed including soft and hard remanence as well as magnetization of the magnetic torquer, radiation from the Tri-Band Beacon, and interferences from the rotation of the solar wing. A comparison shows consistency between the HPM and SWARM magnetic field data. Observation examples are introduced in the paper, which show that HPM data can be used to survey the global geomagnetic field and monitor the magnetic field disturbances in the ionosphere.

Significance Lipid vesicles are globular assemblies that compartmentalize, encapsulate, transport, and provide signal transmission and communication between cells. In living systems, these vesicles perform critical functions to sustain life. Biomimetic lipid vesicles, such as liposomes, have been developed as mimics of biological cell membranes and for applications in biotechnology, but they do have specific limitations. Dendrimersomes are vesicles self-assembled from amphiphilic Janus dendrimers. They offer improved stability and versatility over liposomes. These dendrimersomes are extremely efficient at loading hydrophobic small molecules and natural macromolecules including folded proteins, at a level higher than comparable liposomes. Additionally, they can be readily functionalized to enable modular recruitment of proteins and nucleic acids on their periphery., Reconstructing the functions of living cells using nonnatural components is one of the great challenges of natural sciences. Compartmentalization, encapsulation, and surface decoration of globular assemblies, known as vesicles, represent key early steps in the reconstitution of synthetic cells. Here we report that vesicles self-assembled from amphiphilic Janus dendrimers, called dendrimersomes, encapsulate high concentrations of hydrophobic components and do so more efficiently than commercially available stealth liposomes assembled from phospholipid components. Multilayer onion-like dendrimersomes demonstrate a particularly high capacity for loading low-molecular weight compounds and even folded proteins. Coassembly of amphiphilic Janus dendrimers with metal-chelating ligands conjugated to amphiphilic Janus dendrimers generates dendrimersomes that selectively display folded proteins on their periphery in an oriented manner. A modular strategy for tethering nucleic acids to the surface of dendrimersomes is also demonstrated. These findings augment the functional capabilities of dendrimersomes to serve as versatile biological membrane mimics.

Defluorinative C(sp3 )-P bond formation of α-trifluoromethyl alkenes with phosphine oxides or phosphonates have been achieved under catalyst- and oxidant-free conditions, giving phosphorylation gem-difluoroalkenes as products. α-Trifluoromethyl alkenes bearing various of aryl substituents such as halogen, cyano, ester and heterocyclic groups are available in this transformation. The results of control experiments demonstrated that the mechanism of dehydrogenative/defluorinative cross-coupling reactions was not a radical route, but might be an SN 2' process involving phosphine oxide anion.

The aim of the study was to determine the feasibility of the Vitellaria paradoxa nutshell as a new medicinal resource for treating diabetes. A total of forty-one compounds were identified by HPLC-DAD-Q-TOF-MS and phytochemical methods in V. paradoxa nutshell methanol extract. Based on HPLC fingerprints, four characteristic constituents were quantified and the origin of twenty-eight V. paradoxa nutshells from seven sub-Saharan countries was compared, which were classified into three groups with chemometric method. Twenty-eight samples contained high total phenolic content, and exhibited moderate-higher antioxidant activity and strong α-glucosidase inhibitory activity. Furthermore, all fractions and isolated compounds were evaluated for their antioxidant and α-glucosidase inhibitory activities, and α-glucosidase inhibitory action mechanism of four characteristic constituents including protocatechuic acid, 3, 5, 7-trihydroxycoumarin, (2R, 3R)-(+)-taxifolin and quercetin was investigated via molecular docking method, which were all stabilized by hydrogen bonds with α-glucosidase. The study provided an effective approach to waste utilization of V. paradoxa nutshell, which would help to resolve waste environmental pollution and provide a basis for developing potential herbal resource for treating diabetes.

The mesoporous hollow carbon spheres have been prepared by thermal oxidation etching strategy, and characterized by transmission electron microscopy and the Brunauer-Emmett-Teller method. The mesoporous hollow carbon spheres can be obtained by means of controlling the thermal oxidation times of solid carbon spheres in air. The mesoporous hollow carbon spheres at the optimum thermal oxidation time of 1.5 h in air showed the highest specific surface and the highest total pore volume. Furthermore, the hollow carbon sphere-sulfur composite cathodes achieved high initial discharge capacity of 1423.9 mAh g−1, excellent discharge capacity and excellent rate performance.

Frank-Kasper phases and liquid quasicrystals self-organize from supramolecular spheres of dendrimers, block copolymers, surfactants and other self-assembling molecules. These spheres are expected to be achiral due to their isotropic shape. Nevertheless, supramolecular spheres from short helical stacks of crown-like dendrimers self-organize a Pm3 n cubic (Frank-Kasper A15) phase which exhibits chirality on the macroscopic scale. However, the chirality of classic isotropic supramolecular micellar-like spheres, generated from conical dendrons, is unknown. Here we report a library of second and third generation biphenylpropyl dendrons with chiral groups at their apex that produces single-handed chiral supramolecular spheres. Up to 480 conical dendrons self-assemble to form micellar-like spheres, with a molar mass of up to 1.1 × 106 g/mol, that self-organize into a Pm3 n phase with chirality detectable on the macroscopic scale. This demonstration of chirality in micellar-like spheres of a Frank-Kasper phase raises the fundamental question whether micellar-like spheres forming 3D phases generated from other soft matter such as block copolymers, surfactants, and other molecules are chiral.

Copper is widely used in many applications due to its excellent electric conductivity, processing ductility and corrosion resistance. However, poor hardness and low strength are the major limitations of copper in many fields. Herein, we report a high-performance copper matrix composites prepared by powder metallurgy. The copper matrix composites were prepared by mixed acid treatment, molecular-level method, ball milling and spark plasma sintering (SPS) process. The fabrication, microstructure, mechanical properties and electrical conductivity of the composites were investigated. The results show that nano-Al2O3 can act as an active mixing agent to disperse CNTs in copper powders and increase the adhesion between CNTs and copper matrix in composites. Additionally, the uniform dispersion of Al2O3 and CNTs can restrict the grain growth and form a strong bonding interface. Thus, the synthesized Cu-1.5CNTs-0.5Al2O3 composite displays the highest comprehensive performance, such as 131 HV hardness, 345 MPa ultimate tensile strength, 324 MPa yield strength, 13.8% elongation, and 50.6 MS/m (87.2%IACS) electrical conductivity. This work provides a feasible way to prepare high-performance copper matrix composites.

Light-matter interactions are extremely important, as they sustain life on Earth and can be tailored for diverse applications in areas such as solar energy conversion, chemical sensing, and information storage. One key process of these interactions is the absorption of photons. We demonstrate a novel material capable of absorbing up to 98% of incident visible light. The material comprises a thin sheet of a tightly packed two-dimensional lattice of metal nanoparticles, called plasmene, supported by a thin (subwavelength) dielectric film deposited on top of a mirror. We demonstrate how the resulting metasurface absorbers are useful in surface-enhanced spectroscopy and in the generation of plasmonic hot carriers. These structures hold great promise for applications in structural color, sensing, and photocatalysis.

A lysosome-specific fluorescent probe, Lyso-AC, for biothiols was developed by incorporation of a 4-nitrophenol moiety into a coumarin dye. The Cys/Hcy-triggered substitution-rearrangement cascade, and GSH-induced substitution reaction lead to the corresponding blue emissive amino-coumarin and yellow emissive thiol-coumarin, thereby enabling Cys/Hcy and GSH detection from distinct emissions. Moreover, this probe displayed an excellent lysosome targeting property with a 0.92 Pearson's colocalization coefficient by using Neutral Red as a reference. Significantly, biological experiments indicated Lyso-AC has the potential to monitor lysosome Cys/Hcy and GSH simultaneously in living HeLa cells from distinct emissions.

A robust fluorescent probe, MCP1, was developed for triple-detection of H2S, H2Sn and biothiols for the first time. Introduction of H2S, H2Sn and biothiols to MCP1 lead to distinct emission peaks at 508, 576 and 469 nm, respectively, enabling simultaneous detection of H2S, H2Sn and biothiols from distinct emission channels.

The encapsulation or coating of conductive materials is an effective strategy to increase the electrochemical ion-storage performance of some promising electrode materials such as transition metal oxides and sulfides, which are low-cost and have high capacity, but their practical applications are hindered by their intrinsically low conductivity and large volume changes during cycling; however, to date, the effect of the thickness of conductive layers on the ion-storage performance has been rarely studied. In this study, taking nanoscale polypyrrole (PPY)-coated FeS2 as an example, the effect of the critical thickness of the conductive PPY coating on the lithium-ion storage performance of (PPY)-coated FeS2 as a cathode of rechargeable lithium-ion batteries (LIBs) was investigated. Via a facile vapor-phase polymerization method, uniform PPY coatings with the thickness of 1–18 nm on microsized FeS2 particles were prepared. It was found that the critical thickness of PPY was 5 nm, at which the PPY-coated FeS2 cathode exhibited remarkablely superior high-rate capability (808, 583, 543, 511, and 489 mA h g−1 at 0.1, 1, 2, 5 and 10 A g−1, respectively) and long-term stability (504 mA h g−1 at 1.0 A g−1 after 500 cycles) as compared to those with other coating thicknesses owing to the acheivement of optimal electrical conductivity and ion diffusion efficiency. Thus, this study provides an insight into the critical thickess of a surface-functionalized coating of active materials and opens a new avenue for the futher enhancement of the performance of energy storage deivces.

An effective ratiometric electrochemical biosensing platform was developed for ultrasensitive and highly specific detection of the K-rat sarcoma (K-ras) gene via exonuclease III (Exo III)-assisted target recycling and rolling circle amplification (RCA) strategies. The ferrocene-modified hairpin capture probe (Fc-HP-SH) labeled with ferrocene (Fc) at the 3′ terminus and a thiol group at the 5′ terminus and a padlock probe were chosen to fabricate the ratiometric electrochemical biosensor. Fc-HP-SH self-assembled on the surface of a gold electrode through the Au–S bond, and 6-mercaptohexanol was added to block the unspecific adsorption sites on the gold electrode surface. In the presence of the target K-ras gene and Exo III, the K-ras gene specifically hybridized with the specific 3′ terminal sequences of Fc-HP-SH to open the hairpin structure. Meanwhile, Exo III cleaved the DNA duplex to release the target K-ras gene for the target recycling process. The residual single-stranded oligomers were elongated during the RCA process, and hemin specifically bound with these long oligonucleotides to form a stable G-quadruplex/hemin complex. Consequently, the variations of the differential pulse voltammetry (DPV) peak currents of Fc (IFc) and the G-quadruplex/hemin complex (IG-quadruplex/hemin) resulted in an obvious increase of the ratio of DPV peak currents IG-quadruplex/hemin/IFc. Under optimum experimental conditions, the dynamic response range was in the range of 0.5 fM to 10 pM with a detection limit of 0.28 fM (S/N = 3). This method highly recognized the target K-ras gen and its mutants, and such method was successfully applied in human serum samples. The proposed method possesses potential applications in monitoring of serious diseases and clinical molecular diagnosis.

Ring-like particles have received considerable attention due to their unique interior cavity and properties. However, the preparation of stimuli-responsive nanosized rings with internal size smaller than 100 nm remains unexplored likely due to the challenges encountered in their synthesis. The successful fulfillment of this target will not only significantly enrich the family of ring-like nanoparticles but also build a connection that bridges ring-like nanoparticles and cyclic polymers. For this purpose, we report in this study a controlled synthesis of stimuli-responsive ring-like colloids and cyclic polymers using both star-shaped polymers and β-cyclodextrin (β-CD) as the dual templates. The first template comprising star-shaped polymers generated a ring-like structure and adoption of β-CD as the second template further restricted the ring thickness to the height of a β-CD, leading to the generation of stimuli-responsive nanosized ring-like colloids with ring thickness less than 1 nm, which shifted the ring-like structure to cyclic polymers with reversible cross-linked disulfide bridges. The reported “dual-template” approach is thus a valuable alternative to the current synthetic strategies toward stimuli-responsive ring-like colloids and cyclic polymers.

A new electrophilic selenocyanation reagent, selenocyano-benziodoxolone, was successfully prepared from 2-iodobenzoic acid in two steps (71% overall yield). A variety of α-selenocyanated ketones and β-ketoesters, including selenocyanate-containing steroid derivatives, have been achieved by using this newly developed selenocyano-benziodoxolone in good to excellent yields (up to 99%) simply by grinding under mild conditions.

Significance Gram-negative bacterial cells such as Escherichia coli contain a relatively rigid outer membrane, and cross-linked peptidoglycan in their periplasm, giving them the rigidity and stability to survive independently in harsh environments. To dismantle these strong bacterial cell envelopes, enzymatic processes need to be used. In contrast, human cell membranes are much more fragile, making it possible to dismantle them more easily by relatively mild mechanical disruption. Once these membranes are dismantled, they can be coassembled with synthetic phospholipid mimics, named Janus dendrimers, into cell-like hybrids. This method stabilizes the delicate human cell membranes, introducing the potential for the study of human cell membranes and of their constituents in vitro in a more robust environment., Cell-like hybrids from natural and synthetic amphiphiles provide a platform to engineer functions of synthetic cells and protocells. Cell membranes and vesicles prepared from human cell membranes are relatively unstable in vitro and therefore are difficult to study. The thicknesses of biological membranes and vesicles self-assembled from amphiphilic Janus dendrimers, known as dendrimersomes, are comparable. This feature facilitated the coassembly of functional cell-like hybrid vesicles from giant dendrimersomes and bacterial membrane vesicles generated from the very stable bacterial Escherichia coli cell after enzymatic degradation of its outer membrane. Human cells are fragile and require only mild centrifugation to be dismantled and subsequently reconstituted into vesicles. Here we report the coassembly of human membrane vesicles with dendrimersomes. The resulting giant hybrid vesicles containing human cell membranes, their components, and Janus dendrimers are stable for at least 1 y. To demonstrate the utility of cell-like hybrid vesicles, hybrids from dendrimersomes and bacterial membrane vesicles containing YadA, a bacterial adhesin protein, were prepared. The latter cell-like hybrids were recognized by human cells, allowing for adhesion and entry of the hybrid bacterial vesicles into human cells in vitro.

Herein, a simple and efficient fluorescent assay for Ag+ ions and l -cysteine (L-Cys) in complex biological fluids and living cells was first developed based on the fluorescent “on-off-on” mode of red emission nitrogen, boron, sulfur co-doped carbon dots (NBS-CDs). Red emission NBS-CDs were prepared via one-step hydrothermal synthesis by using 3-aminobenzeneboronic acid and 2,5-diaminobenzenesulfonic acid as precursors. Such NBS-CDs exhibited excellent optical properties and relatively high absolute fluorescent quantum yield compared with some reported NBS-CDs. Due to the strong quenching ability of Ag+ ions on the fluorescence of NBS-CDs, red emission NBS-CDs were used for the determination of Ag+ ions with high sensitivity and excellent selectivity. The fluorescence of NBS-CDs was recovered after the interaction between Ag+ ions and L-Cys, which realized the specific determination of L-Cys in human urine samples and human plasma samples. The established NBS-CDs-based fluorescent “on-off-on” sensor offered a relatively low detection limits of 0.35 μM for Ag+ ions and 0.045 μM for L-Cys based on three times signal-to-noise criteria. Notably, this strategy was applied for the visual detections of Ag+ ions and L-Cys in living human cancer cells (HeLa cells and MCF-7 cells). This method is simple, high sensitive, and excellent selectivity, which provided a new insight on the potential applications of NBS-CDs to develop the biosensor in clinical diagnosis and other biologically related areas.

We propose a new, simple and effective strategy to enhance the electro-catalytic activity by regulating the valence states of the electro-catalyst. The proportion of Ni3+/Ni2+ on the ammonium nickel phosphate/nickel foam electrode surface was increased after H2O2 solution treatment. The kinetic analysis results showed catalytic rate constants (Kcat) of Ni3+-rich surface electrode (4.028 × 106 cm3·mol−1·s−1) is bigger than the original electrode (4.928 × 105 cm3·mol−1·s−1), suggesting higher electro-catalytic activity of Ni3+-rich surface electrode. Ni3+-rich surface electrode shows an ultra high sensitivity (11,361 µA·mM−1·cm−2) in the range of 0.001–1 mM, which is much higher than the original electrode in the same linear range. And the sensitivity of 3579.9 µA·mM−1·cm−2 of Ni3+-rich surface electrode in the range of 2–4 mM is also enhanced compared with the original electrode.

Frank-Kasper phases are available in both hard and soft complex matter. They have been discovered in metal alloys and subsequently in self-organisations of supramolecular spheres from self-assembling dendrons, dendrimers and dendronized polymers. Recently, they were found in block copolymers, lipids, surfactants, giant surfactants, nanoparticles, DNA particles and even in condensed small molecules such as N2, O2, and CO. Here we report the discovery of an amphiphilic Janus dendrimer, that self-assembles in water into vesicles known as dendrimersomes, self-organised also in bulk state into helical columns and spheres forming columnar hexagonal and a Frank-Kasper A15 phase known as Pm3��n. These self-organisations display a supramolecular orientational memory (SOM) effect that is induced by an epitaxial nucleation at the transition from columns to spheres and during the reverse process. This SOM effect is mediated by the closed contact supramolecular spheres from the A15 phase. In this case a rhombitruncated cuboctahedral hexagonal columnar arrangement, that to the best of our knowledge is not known in biology or synthetic chemistry, was self-organised. We believe that the addition of amphiphilic Janus dendrimers to the classes of molecules displaying Frank-Kasper phases and the SOM effect will broaden our ability to discover additional complex soft condensed matter morphologies.

Organometallic rhodium(III) complexes with curcuminoid ligands attracted considerable attention in biological-related fields and the variation of curcuminoid ligands may regulate the biological activity of these organometallic rhodium(III) complexes. To deeply evaluate the biological influences of these complexes, the binding interactions between three rhodium(III) complexes with curcuminoid ligands and human serum albumin (HSA) were comparably investigated by spectroscopic and electrochemical techniques. The results suggested that the intrinsic fluorescence of HSA was quenched by three complexes through static fluorescence quenching mode. Three complexes bonded with Sudlow's site I of HSA to form ground-state compounds under the binding forces of van der Waals interactions, hydrogen bonds formation, and protonation. Finally, the native conformational structure and the thermal stability of HSA were all changed. Space steric hindrance of complexes took part in the differences of the fluorescence quenching processes, and the chemical polarity of the complexes played a vital role in the variations of the structure and biological activity of HSA. These results illustrated the molecular interactions between protein and organometallic rhodium(III) complexes with curcuminoid ligands, offering new insight about the prospective applications of analogical rhodium(III) complexes in biomedicine areas.

Biological macromolecules such as proteins and nucleic acids are monodisperse just as low-molar-mass organic compounds are. However, synthetic macromolecules contain mixtures of different chain lengths, the most uniform being generated by living polymerizations, which exhibit a maximum of 1–3% of chains with the desired length. Monodisperse natural and synthetic oligomers can be obtained in low quantities by tedious, multistep iterative methods. Here we report a methodology to synthesize monodisperse synthetic macromolecules by self-interrupted living polymerization. This methodology relies on a concept that combines supramolecular and macromolecular chemistry and differs from the conventional reactivity principles employed in the synthesis of polymers for over 100 years.

A one-pot hydrothermal synthesis of manganese-doped carbon dots (Mn-CDs) is reported for fluorescent “on-off-on” determination of Mn(VII) and L-ascorbic acid (L-AA) in aqueous solution and living cells. Mn-CDs were prepared by using sulfanilic acid, tetrakis(hydroxymethyl)phosphonium chloride, and Mn(II) chloride as precursors. Mn-CDs were characterized by several spectroscopic methods and microscopic techniques. Mn-CDs show distinctly long fluorescence lifetime (12.39 ± 0.07 ns) and high absolute fluorescence quantum yield (around 37%) with excitation and emission wavelengths of 362 and 500 nm, respectively. Mn-CDs exhibit no significant cytotoxicity to human cervical carcinoma HeLa cells and human embryonic kidney HEK-293T cells at 200 μg mL−1 level after 48 h incubation. The fluorescence of Mn-CDs at 500 nm (excited at 362 nm) is quenched efficiently by Mn(VII) and can be further recovered after the addition of L-AA, resulting in a fluorescent “on-off-on” assay for the determination of Mn(VII) and L-AA. Under optimal experimental conditions, the linear response covers the 3 to 150 μM Mn(VII) concentration range and the 3 to 140 μM L-AA concentration range. This method offers relatively low detection limits of 0.66 μM for Mn(VII) and 0.90 μM for L-AA. This strategy was applied to visual determination of Mn(VII) and L-AA in living HeLa cells with satisfying results.

Characterizating the complete mitochondrial genome (mitogenome) of an organism allows detailed genomic studies in systematics and evolution. The present study decodes the mitogenome (17,062 bp) of the many-lined sun skink, Eutropis multifasciata, using next-generation sequencing. To compare the diversity of mitogenomic structure and investigate intraspecific evolutionary relationships among the Asian Scincomorpha, the mitogenomes of 46 other species were examined concurrently. Within the group, the size of mitogenomes varied predominantly in the length at their control regions. The Ka/Ks ratios of 12 protein codon genes (PCGs) were lower than 1.00, demonstrating that they were under relaxed or moderate purifying selection . However, the ND5 had a Ka/Ks ratio >1, and was considered to be under positive selection. Currently there are two superfamilies in Scincomorpha (i.e. Scincoidea and Lacertoidea), but phylogenetic analysis using Bayesian Inference and Maximum-Likelihood Estimations produced phylogenetic trees with three clades in Scincomorpha ((Scincoidea + Lacertoidea (part)) + Gymnophthalmidae)).

A ratiometric fluorescent assay is fabricated for the evaluation of alkaline phosphatase (ALP) activity. This assay is composed of ionic liquid–functionalized carbon dots (IL-CDs) with blue fluorescence signal at 470 nm and 2,3-diaminophenazine (DAP) with yellow fluorescence signal at 570 nm. IL-CDs were synthesized via electrochemical method by using ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) and ultrapure water as precursors. DAP is produced by the oxidation reaction between o-phenylenediamine and H2O2 under the catalysis of horseradish peroxidase. H2O2 is reduced by ascorbic acid which is the hydrolysis product of ascorbic acid 2-phosphate under the catalysis of ALP, finally reducing the amount of DAP. The activity of ALP is evaluated through the ratiometric fluorescent signal between IL-CDs and DAP via Forster resonance energy transfer. Under optimal experimental conditions, this ratiometric fluorescent assay has a response that covers the 0.04 to 3.2 U L−1 (12 to 960 pM) ALP activity. This assay possesses ultralow detection limit of 0.012 U L−1 (3.6 pM) for ALP and high selectivity for ALP among several enzymes. The method was used to measure ALP activity in human serum samples with satisfying results.