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Although many dopant-free hole transport materials (HTMs) for perovskite solar cells (PSCs) have been investigated in the literature, novel and useful molecular designs for high-performance HTMs are still needed. In this work, a hydrogen-bonding association system (NH⋯CO) between amide and carbonyl is introduced into the pure HTM layer. Our study demonstrates that the hydrogen-bonding association can not only significantly increase the HTM’s hole transport mobility and functionalize the surface passivation to the perovskite layer, but also form Pb–N coordination bonds at the interface to promote the hole extraction while hindering the interfacial charge recombination. As a result, the PSCs based on dopant-free hydrogen-bonded HTMs can achieve a champion power conversion efficiency (PCE) of 21.62%, which is around 32% higher than the pristine PSC without the hydrogen-bonding association. Furthermore, the dopant-free hydrogen-bonded HTMs based device shows remarkable long-term light stability, retaining 87% of its original value after 500 h continuous illumination, measured at the maximum power point. This work not only provides a potential HTM with hydrogen-bonding association in PSCs, but also demonstrates that introducing hydrogen bonding into the materials is a useful and simple strategy for developing high-performance dopant-free HTMs. publishedVersion

While palladium-based catalysts are effective in low-temperature methane combustion, their high cost and scarcity render them unsuitable to fulfil the growing demand. The design of improved catalysts which can more efficiently utilize this precious metal is required. Here, by using a facile one-pot thermal decomposition method Pd-NiCo2O4 spinel catalysts with a unique structure are obtained, in which the majority of Pd incorporated into the bulk spinel structure of NiCo2O4 with limited highly dispersed PdOx species on the surface at an atomic scale. The robust 1 %Pd-NiCo2O4 spinel catalyst exhibits comparable activity in methane oxidation to that of the conventional incipient wetness impregnation 2 %Pd/NiCo2O4. Theoretical calculations and catalyst characterizations (SEM, HRTEM, XRD, XPS, XAS, ICP-OES, etc.) revealed that the enhanced activity is mainly originated from having the O p-band center closer to the Fermi level, with Pd ions incorporated into the bulk NiCo2O4 via substituting for the octahedral coordinated Ni3+/Co3+.

Based on their characteristics, transition metal layered double hydroxides have been of great scientific interest for their use in supercapacitors. Up until now, severe aggregation and low intrinsic conductivity have been the major hurdles for their application. In this work, nickel–iron sulfide nanosheets (NiFeSx) and carbon nanotubes (CNTs) were synthesized on diatomite using chemical vapor deposition and a two-step hydrothermal method to overcome these challenges. Synthesis of this composite successfully exploits the synergistic effect of multicomponent materials to improve the electrochemical performance. Diatomite is selected as a substrate to provide preferable surroundings for the uniform dispersion of nanomaterial on its surface, which enlarges the active sites that come in contact with the electrolytes, significantly improving the electrochemical properties. Combined with high conductivity and a synchronous sulfurization effect, the NiFeSx@CNTs@MnS@Diatomite electrode delivered a high specific capacitance of 552F g−1 at a current density of 1 A g−1, a good rate capability of 68.4% retention at 10 A g−1, and superior cycling stability of 89.8% capacitance retention after 5000 cycles at 5 A g−1. Furthermore, an asymmetric supercapacitor assembled via NiFeSx@CNTs@MnS@Diatomite and graphene delivered a maximum energy density of 28.9 Wh kg−1 and a maximum power density of 9375 W kg−1 at a potential of 1.5 V. This research lays the groundwork for ideal material preparation as well as a rational design for the electrode material, including property enhancement of diatomite-based material for use in supercapacitors.

Stormwater runoff samples were collected from five different land use sites (gas station, city road, campus, park, and residential) in a precipitation event on May 22nd, 2017, from a small suburban area (5 km × 2 km) of the city of Beijing, China. There were 72 types of semi-volatile organic compounds (SVOCs) found in these runoff samples, including 33 types of monocyclic aromatic hydrocarbons (MAHs), 22 types of polycyclic aromatic hydrocarbons (PAHs), 6 types of phthalate esters (PAEs), 9 types of pesticides and 2 types of polychlorinated biphenyls (PCBs). Especially, 26 types of SVOCs (7 MAHs, 9 PAHs, 5 PAEs, and 5 pesticides) were detected in all water samples. SVOCs concentrations were higher in the samples from gas station and city road, and lower in runoff from campus, park and residential sites. The change in the ratio of anthracene to anthracene plus phenanthrene (ANT/(ANT + PHE)) in this study, reflected the importance of PAH source and land use. Di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate, are two of the phthalate esters 100% detected in the runoff samples. The city road runoff DEHP concentrations recorded the highest values (> 6000 ng/L), however, were still less than those wastewater DEHP pollutants measured in developed countries (e.g. UK, Canada, Finland, etc.). One-way ANOVA analysis in this study, showed that land use could significantly influence 23 SVOCs in the runoff samples, whereas the runoff SVOCs in different precipitation period showed no statistical changes in the five sites, and presented a general temporal trends “high (beginning)—low (middle period)—little raising (ending)”. The findings in this study could be used in municipal management of wastewater collection and treatment.

Drought is a critical abiotic stressor that modulates soybean yield. Drought stress drastically enhances reactive oxygen species (ROS) formation, and maintaining ROS content above a cytostatic level but below a cytotoxic level is essential for normal biology processes in plants. At present, most of the known ROS-scavenging systems are in the cytoplasm, and the mechanism of ROS regulation in the nucleus remains unclear. GmNTF2B-1 is a member of the IV subgroup in the nucleus transporter family. Its expression is localized to the roots and is stimulated by drought stress. In this study, the overexpression of GmNTF2B-1 was found to improve the drought tolerance of transgenic soybean by influencing the ROS content in plants. An oxidoreductase, GmOXR17, was identified to interact with GmNTF2B-1 in the nucleus through the yeast two-hybrid, coimmunoprecipitation and bimolecular fluorescence complementation assays. The drought tolerance of GmOXR17 transgenic soybean was similar to that of GmNTF2B-1. GmNTF2B-1 was expressed in both cytoplasm and nucleus, and GmOXR17 transferred from the cytoplasm to the nucleus under drought stress. The overexpression of GmNTF2B-1 enhanced the nuclear entry of GmOXR17, and the overexpression of GmNTF2B-1 or GmOXR17 could decrease the H2 O2 content and oxidation level in the nucleus. In conclusion, the interaction between GmNTF2B-1 and GmOXR17 may enhance the nuclear entry of GmOXR17, thereby enhancing nuclear ROS scavenging to improve the drought resistance of soybean.

Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) show great therapeutic potential for osteoarthritis (OA). However, their low bioavailability through intraarticular injection inhibits the process of clinical application. In the present study, an injectable Diels-Alder crosslinked hyaluronic acid/PEG (DAHP) hydrogel was developed as an intraarticular delivery platform for MSC-sEVs. Our results showed that the DAHP hydrogel could be prepared easily and that its gelation properties were suitable for intraarticular administration. In vitro studies demonstrated that the DAHP hydrogel could achieve sustained release of MSC-sEVs mainly by degradation control and preserve the therapeutic functions of sEVs. An in vivo experiment revealed that the DAHP hydrogel could enhance the efficacy of MSC-sEVs for OA improvement. This study provides a suitable delivery platform for MSC-sEVs-based OA therapy. STATEMENT OF SIGNIFICANCE: Mesenchymal stem cell (MSC)-derived small extracellular vesicles (MSC-sEVs) have shown a high potential as a cell-free therapeutic factor for treating osteoarthritis (OA). The sustained release of these MSC-sEVs in the joint space is essential for their clinical application. Herein, an injectable Diels-Alder crosslinked hyaluronic acid/PEG (DAHP) hydrogel was developed for intraarticular release of MSC-sEVs. The properties of the DAHP hydrogel, namely gelation features, cytocompatibility, sustained release, and functional maintenance of MSC-sEVs, make it suitable for intraarticular injection and delivery of sEVs. The efficacy of MSC-sEVs was enhanced by the intraarticularly injected DAHP hydrogel. Our present study provides a promising sustained delivery platform for MSC-sEVs for treating OA.

Exorbitant aldosterone is closely associated with various severe diseases, including congestive heart failure and chronic kidney disease. As aldosterone synthase is the pivotal enzyme in aldosterone biosynthesis, its inhibition constitutes a promising treatment for these diseases. Via a structure-based approach, a series of pyridyl substituted 3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-ones were designed as inhibitors of aldosterone synthase. Six compounds (5j, 5l, 5m 5w, 5x and 5y) distinguished themselves with potent inhibition (IC50

More and more studies have recognized that the nanosized pores of hydrogels are too small for cells to normally grow and newly formed tissue to infiltrate, which impedes tissue regeneration. Recently, hydrogels with macropores and/or controlled degradation attract more and more attention for solving this problem. Sodium alginate/Bioglass (SA/BG) hydrogel, which has been reported to be an injectable and bioactive hydrogel, is also limited to be used as tissue engineering scaffolds due to its nanosized pores. Therefore, in this study, degradation of SA/BG hydrogel was modulated by grafting deferoxamine (DFO) to SA. The functionalized grafted DFO-SA (G-DFO-SA) was used to form G-DFO-SA/BG injectable hydrogel. In vitro degradation experiments proved that, compared to SA/BG hydrogel, G-DFO-SA/BG hydrogel had a faster mass loss and structural disintegration. When the hydrogels were implanted subcutaneously, G-DFO-SA/BG hydrogel possessed a faster degradation and better tissue infiltration as compared to SA/BG hydrogel. In addition, in a rat full-thickness skin defect model, wound healing studies showed that, G-DFO-SA/BG hydrogel significantly accelerated wound healing process by inducing more blood vessels formation. Therefore, G-DFO-SA/BG hydrogel can promote tissue infiltration and stimulate angiogenesis formation, which suggesting a promising application potential in tissue regeneration., Graphical abstract Image 1, Highlights • A new strategy to modulate sodium alginate hydrogel degradation was proposed. • The hydrogel was injectable and could induce vascularization. • The hydrogel was beneficial for tissue penetration and wound healing.

Extracellular vesicles (EVs) are membrane-encapsulated particles with critical biomedical functions, including mediating intercellular communication, assisting tumor metastasis, and carrying protein and microRNA biomarkers. The downstream applications of EVs are greatly influenced by the quality of the isolated EVs. However, almost none of the separation methods can simultaneously achieve both high yield and high purity of the isolated EVs, thus making the isolation of EVs an essential challenge in EV research. Here, we developed a magnetic bead-mediated selective adsorption strategy (MagExo) for easy-to-operate EV isolation. Benefited from the presence of an adsorption window between EVs and proteins under the effect of a hydrophilic polymer, EVs tend to adsorb on the surface of magnetic beads selectively and can be separated from biological fluids with high purity by simple magnetic separation. The proposed method was used for EV isolation from plasma and cell culture media (CCM), with two times higher yield and comparable purity of the harvested EVs to that obtained by ultracentrifugation (UC). Downstream applications in proteomics analysis showed 86.6% (plasma) and 86.5% (CCM) of the analyzed proteins were matched with the ExoCarta database, which indicates MagExo indeed enriches EVs efficiently. Furthermore, we found the target RNA amount of the isolated EVs by MagExo were almost dozens and hundred times higher than the gold standard DG-UC and ultracentrifugation (UC) methods, respectively. All the results show that MagExo is a reliable, easy, and efficient approach to harvest EVs for a wide variety of downstream applications with minimized sample usage. STATEMENT OF SIGNIFICANCE: Extracellular vesicles (EVs) are presently attracting increasing interest among clinical and scientific researchers. Although the downstream applications of EVs are recognized to be greatly affected by the quality of the isolated EVs, almost none of the separation methods can simultaneously achieve high yield and high purity of the isolated EVs; this makes the isolation of EVs an essential challenge in EV research. In the present work, we proposed a simple and easy-to-operate method (MagExo) for the separation and purification of EVs based on the phenomenon that EVs can be selectively adsorbed on the surface of magnetic microspheres in the presence of a hydrophilic polymer. The performance of MagExo was comparable to or even better than that of gold standard methods and commercial kits, with two times higher yield and comparable purity of the harvested EVs to that achieved with ultracentrifugation (UC); this could meet the requirements of various EV-associated downstream applications. In addition, MagExo can be easily automated by commercial liquid workstations, thus significantly improving the isolation throughput and paving a new way in clinical diagnosis and treatment.

Achieving "zero liquid discharge" is a requirement for the development of the coal chemical industry; high pollutant concentration, strong biotoxicity, and poor biodegradability (BOD5/COD=0.1–0.2) make fixed-bed coal gasification wastewater difficult to treat. This study synthesized a Fe-Mn/lava catalyst (FMLC) and performed a pilot-scale test on catalytic ozonation for the pretreatment of fixed-bed coal gasification wastewater. The effects of ozone and catalyst dosages were investigated, and the changes in the organics, biotoxicity, and biodegradability of wastewater were analyzed using three-dimensional fluorescence spectroscopy, BOD5/COD, and specific oxygen uptake rate (SOUR). Energy consumption was also calculated. The removal efficiencies (at a flow rate of 1.0 m3/h, ozone dosage of 179 g/h, and catalyst dosage of 40 kg/m3) of COD and BOD5 were 61.77% and 16.98%, respectively, after 30 days of continuous operation. Toxic refractory macromolecular organic pollutants were transformed into small, biodegradable substances. BOD5/COD increased from 0.16 to 0.35, and SOUR decreased from 2.8460 to 2.3180 mgO2/(gMLSS∙h). The operating cost was 1.24 kWh/kgCOD. Catalytic ozonation as a pretreatment technology markedly improved biodegradability, reduced biotoxicity, and looks to be promising for treating fixed-bed coal gasification wastewater.

Electrospun nanofibers are of the same length scale as the native extracellular matrix and have been extensively reported to facilitate adhesion and proliferation of cells and to promote tissue repair and regeneration. With a primary focus on tissue repair and regeneration using electrospun scaffolds, only a few studies involved electrospun nanofiber scaffolds directing cell behaviors have been reported. In this study, we prepared electrospun nanofiber scaffolds with distinct fiber configurations, namely, random and aligned orientations of nanofibers, as well as oriented yarns, and investigated their effects on cell behaviors. Our results showed that these scaffolds supported good proliferation and viability of murine fibroblasts. Fiber configuration profoundly influenced cell morphology and orientation but showed no effects on cell proliferation rate. The yarn scaffold had comparable total protein accumulation with the random and aligned scaffolds, but it supported a greater proliferation rate of fibroblasts with significantly elevated collagen deposition due to its porous fibrous configuration. Cell-seeded yarn scaffolds showed a greater Young’s modulus compared with cell-free controls as early as 1 week. Together with its unique fiber configuration similar to the native extracellular matrix of the myocardium, the yarn scaffold might be a suitable matrix material for modeling cardiac fibrotic disorders.

BACKGROUND: The ribose-binding protein (RBP) from Escherichia coli is one of the representative structures of periplasmic binding proteins. Binding of ribose at the cleft between two domains causes a conformational change corresponding to a closure of two domains around the ligand. The RBP has been crystallized in the open and closed conformations. OBJECTIVE: With the complex trajectory as a control, our goal was to study the conformation changes induced by the detachment of the ligand, and the results have been revealed from two computational tools, MD simulations and elastic network models. METHODS: Molecular dynamics (MD) simulations were performed to study the conformation changes of RBP starting from the open-apo, closed-holo and closed-apo conformations. RESULTS: The evolution of the domain opening angle θ clearly indicates large structural changes. The simulations indicate that the closed states in the absence of ribose are inclined to transition to the open states and that ribose-free RBP exists in a wide range of conformations. The first three dominant principal motions derived from the closed-apo trajectories, consisting of rotating, bending and twisting motions, account for the major rearrangement of the domains from the closed to the open conformation. CONCLUSIONS: The motions showed a strong one-to-one correspondence with the slowest modes from our previous study of RBP with the anisotropic network model (ANM). The results obtained for RBP contribute to the generalization of robustness for protein domain motion studies using either the ANM or PCA for trajectories obtained from MD.

Yttrium aluminum garnet (YAG) transparent ceramics are an attractive material for solid-state laser, optical and high temperature structural applications because of their prominent advantages. However, it is difficult to achieve the high-quality ceramics by acrylamide (AM) aqueous gelcasting due to the inhomogeneous of gel body induced by traditional methods of “catalyst + initiator” or “initiator + heating”. In this work, a series of gel induction contrast experiments were designed to explore a novel gelcasting induction method. With different gelation process, the SEM of surfaces and fracture surfaces and as-fabricated ceramics quality, it was found the effectiveness of the novel gel induction method “vacuum defoaming + initiator”. The method had the ability to improve the uniformity of the gel body by regulating the form of energy injection and having enough time for the stirring of initiator. In addition, the decreasing residual organics would result in contributing to the subsequent debinding and ceramic quality improvement. Therefore, the “vacuum defoaming + initiator” was regarded as an effective induction method to eliminate defect and to achieve the in-line transmittance of as-fabricated YAG ceramic with excellent optical quality at 1064 nm reached 82.8%. This work greatly promotes the application of gelcasting in YAG transparent ceramics.

Density is one of the important parameters of energetic materials. A class of high-density energetic materials was synthesized by a simple method, and all compounds were characterized by NMR, IR, and DSC, and the structures of some compounds were analyzed using single-crystal X-ray diffraction. (5-nitroimino-4-hydro-1,3,4-oxadiazol-2-yl)methyl nitrate (3) (NOMN) showed an outstanding density of 1.898 g/cm3 at 149 K. and the densities of the other compounds exceeded 1.76 g/cm3 at room temperature. Thermal analysis showed that (5-nitroimino-4-hydro-1,3,4-oxadiazol-2-yl)methyl nitrate (3) and 4-amino-1,2,4-triazolium(5-nitroimino-4-hydro-1,3,4-oxadiazol-2-yl) methyl nitrate (3 c) have suitable melting points (86.67°C and 85.65°C) for use as casting materials. The detonation velocity and detonation pressure were calculated by EXPLO5 (v6.01) software, and all compounds showed good explosive performance. The detonation velocity of compound 5-aminotetrazolium (5-nitroimino-4-hydro-1,3,4-oxadiazol-2-yl)methyl nitrate (3e) exceeded that of RDX, but was slightly lower than that of HMX, reaching 9142 m/s. In summary, this series of 1,3,4-oxadiazole-based energetic materials has enriched the family of molten cast carriers and provided new options for the preparation of molten cast explosives.

Nanomaterials and nanotechnology have been widely used in various fields, such as materials, chemical engineering, optics, and other disciplines. In this paper, gold nanoparticles are prepared by the hydrothermal method and treated with polypyrrole coating (PPy-GNPs). Then, the anti-HER2 protein was conjugated to polypyrrole coated gold nanoparticles, and the nanomaterials are named anti-HER2-PPy@GNPs (anti-PPy@GNPs). Their diameter is about 80–90 nm, and they show a strong absorption peak in the near-infrared band, especially under 808 nm laser irradiation. In the MTT test experiment, anti-HER2-PPy@GNPs show a significant inhibitory effect on the SKOV-3 cell. Fluorescent cytoskeletal analysis of SKOV-3 cells and atomic force microscopy (AFM) of the mechanical characteristics of the cell surface revealed that the cell micro-structure, adhesion, and Young's modulus of anti-HER2-PPy@GNPs have changed under the near-infrared illumination. These results indicate anti-HER2-PPy@GNPs has an inhibitory effect on SKOV-3 cells. AFM detects the mechanical characteristics of SKOV-3 cells. Compared with the control group, Young's modulus is increased 52.7%, while the adhesion force is decreased 14.47%.

Transition metal nickel–cobalt hydroxides are widely used as electrode materials for supercapacitors due to their intriguing active component properties. Nevertheless, their aggregation problem and poor electrical conductivity severely hinder their further application as supercapacitor electrodes. Herein, we propose a controllable route for the preparation of nickel–cobalt hydroxide supported on 3D diatomite. The structural evolution of nickel–cobalt hydroxide in different proportions from 2D to 1D was achieved by controlling the raw materials. The sulfuration modification of samples with outstanding performance was also studied via the hydrothermal method. The NiCo–OH@DE nanowires were found to be better than the NiCo-LDH@DE nanosheets. On comparing the samples after sulfuration, it was found that Ni2Co1S@DE sulfurated by Ni2Co1–OH@DE had the best electrochemical performance among all samples. At a current density of 1 A g−1, its specific capacitance reached 917.5 F g−1, and the fabricated Ni2Co1S@DE//AG ASC device exhibited a high energy density of 24 W h kg−1 at 6718 W kg−1, and more than 75% of the capacitance was preserved after 2000 charge/discharge cycles, delivering a stable cycling performance. The impressive performance of the abovementioned Ni2Co1S@DE revealed an effective fabricating strategy for optimizing electrode materials, offering a promising future for high-performance hybrid energy storage devices.

Perovskite oxides based on earth-abundant transition metals have been extensively explored as promising oxygen evolution reaction (OER) catalysts in alkaline media. The (electro)chemically induced transformation of their initially crystalline surface into an amorphous state has been reported for a few highly active perovskite catalysts. However, little knowledge is available to distinguish the contribution of the amorphized surface from that of the remaining bulk toward the OER. In this work, we utilize the promoting effects of two types of Fe modification, i.e., bulk Fe dopant and Fe ions absorbed from the electrolyte, on the OER activity of SrCoO3-δ model perovskite to identify the active phase. Transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the surface amorphization of SrCoO3-δ as well as SrCo0.8Fe0.2O3-δ after potential cycling in Fe-free KOH solution. By further cycling in Fe-spiked electrolyte, Fe was incorporated into the amorphized surface of SrCoO3-δ (SrCoO3-δ + Fe3+), yielding approximately sixfold increase in activity. Despite the difference in remaining perovskites, SrCoO3-δ + Fe3+ and SrCo0.8Fe0.2O3-δ exhibited remarkably similar activity. These results reflect that the in situ developed surface species are directly responsible for the measured OER activity, whereas the remaining bulk phases have little impact.

Bacterial infections cause severe secondary damage to wounds and hinder wound healing processes. We prepared magnesium oxide (MgO) nanoparticle-incorporated nanofibrous membranes by electrospinning and investigated their potential for wound dressing and fighting bacterial infection. MgO-Incorporated membranes possessed good elasticity and flexibility similar to native skin tissue and were hydrophilic, ensuring comfortable contact with wound beds. The cytocompatibility of membranes was dependent on the amounts of incorporated MgO nanoparticles: lower amounts promoted while higher amounts suppressed the proliferation of fibroblasts, endothelial cells, and macrophages. The antibacterial capacity of membranes was proportional to the amounts of incorporated MgO nanoparticles and they inhibited more than 98% E. coli, 90% S. aureus, and 94% S. epidermidis. MgO nanoparticle-incorporated membranes effectively suppressed bacterial infection and significantly promoted the healing processes of infected full-thickness wounds in a rat model. Subcutaneous implantation demonstrated that the incorporation of MgO nanoparticles into electrospun membranes elevated their bioactivity as evidenced by considerable cell infiltration into their dense nanofiber configuration and enhanced the remodeling of implanted membranes. This study highlights the potential of MgO-incorporated electrospun membranes in preventing bacterial infections of wounds.

Fully utilizing the visible light and lowering the economic costs are the toughest challenges of photocatalytic water splitting. To address these issues, a non-noble metal photocatalyst, (CuIn)xZn2(1−x)S2 solid solution with an adjustable band gap by modifying its composition, was synthesized. In addition, amorphous molybdenum sulfide (a-MoSx) was compounded as a co-catalyst on the surface of the solid solution. Compared with crystalline molybdenum sulfide (MoS2), a-MoSx can provide more active sites and reduce the activation energy of hydrogen evolution reactions more effectively. The (CuIn)0.2Zn1.6S2 (CIZS) photocatalyst loaded with 3 wt% a-MoSx exhibited the best photocatalytic performance with a hydrogen evolution rate of 2100 μmol g−1 h−1.

Discrete oligomers are perfect candidates for understanding the structure-dependent properties of polymers. Herein, a series of discrete conjugated oligo(fluorenediacetylene)s (D-oFDAs) with a degree of polymerization (DP) up to 10 were obtained by purification with automated flash column chromatography from polydisperse polymers. It is found that the chain length can affect not only photophysical properties but also crystalline properties. As the DP of D-oFDAs increased, the longer conjugation length caused red shifts in their optical spectra and weaker crystallinity. The effective conjugation length has been extrapolated to be as long as 9 fluorenediacetylene units. Moreover, the oligomers can form uniform films by solution casting for the fabrication of light-emitting diodes, showing that the octamer has the most efficient electroluminescence (EL) properties. When the crystal of the dimer was exposed to 254 nm UV light, only part of the sample was polymerized via a 1,4-addition reaction. Significantly, the simple, scalable and effective strategy provides opportunities to further optimize the structure with diverse blocks and side chains for precisely building macromolecular architectures.

As an environmentally friendly energetic group, the azide group can not only control the melting point but also increase the energy of the compound. Therefore, the design and synthesis of energetic compounds with azido groups have long been a focus of research in the field of energetic materials. 3-R-4-(5-methyleneazide-1,2,4-oxadiazol-3-yl)furazan energetic materials were synthesized and fully characterized. Using computational chemistry methods, the interactions of some compounds were studied, and the physical and chemical properties of all of compounds were examined. The results show that 3-amino-4-(5-methyleneazide-1,2,4-oxadiazol-3-yl)furazan (2) has a melting point similar to that of TNT and can be a potential carrier for molten-cast explosives. Hydroxylamine salt (4) has an excellent detonation velocity and detonation pressure of 9090 m s−1 and 35.76 GPa, respectively, and its energy is significantly higher than that of RDX, enabling replacement of RDX as a high-energy explosive. Although the detonation performance of compound 4 is slightly lower than that of HMX, its sensitivity is better than that of HMX, which shows that compound 4 still has a high application value. Non-covalent interactions (NCIs) and Hirshfeld surface models indicate that hydrogen bonding and π–π interactions are the key factors that reduce the sensitivity of compounds. Therefore, our results for 3-R-4-(5-methyleneazide-1,2,4-oxadiazol-3-yl)furazan energetic materials suggest that it may be competitive for application in both molten-cast explosives and high-energy explosives.

Pharmaceutical and personal care products (PPCPs) are the most common hazardous environmental pollutants. Accordingly, PDI anion radicals are promising photocatalysts to transform PPCPs into non-toxic CO2 and H2O for their clean and efficient production. In the present work, we successfully synthesized an electrophilic PDI supramolecular (sEACA-PDI) compound with high electron affinity through a simple gelation process. Its electron affinity is contributed by its side chain, which enhances the electrophilicity of its perylene core edge. Consequently, sEACA-PDI tends to form anion radicals to provide a SOMO orbital, which allows sEACA-PDI to obtain electrons successively from organic pollutants. Its side chain also generates a polarized surface electric field, building an efficient pathway for electron transfer. The high flexibility and freedom of the sEACA-PDI side chain is beneficial to form a cluster structure. Numerous strongly electrophilic groups are exposed on the surface of sEACA-PDI, which further enhance its electron affinity. sEACA-PDI exhibited high photocatalytic degradation efficiency for classical organic pollutants via successive electrophilic attack, i.e. the k for DCF was 0.923 h−1. Also, sEACA-PDI achieved a k value of 0.351 h−1 for the degradation of MB. This work proposes a promising strategy for developing PDI anion radicals with high electron affinity, and also provides new insights for the treatment of environmental pollutants.

Proton transfer reaction (PTR) is a commonly applied ionization technique for mass spectrometers, in which hydronium ions (H3O+) transfer a proton to analytes with higher proton affinities than the water molecule. This method has most commonly been used to quantify volatile hydrocarbons, but later-generation PTR instruments have been designed for better throughput of less volatile species, allowing detection of more functionalized molecules as well. For example, the recently developed Vocus PTR time-of-flight mass spectrometer (PTR-TOF) has been shown to agree well with an iodide-adduct-based chemical ionization mass spectrometer (CIMS) for products with 3–5 O atoms from oxidation of monoterpenes (C10H16). However, while several different types of CIMS instruments (including those using iodide) detect abundant signals also at “dimeric” species, believed to be primarily ROOR peroxides, no such signals have been observed in the Vocus PTR even though these compounds fulfil the condition of having higher proton affinity than water. More traditional PTR instruments have been limited to volatile molecules as the inlets have not been designed for transmission of easily condensable species. Some newer instruments, like the Vocus PTR, have overcome this limitation but are still not able to detect the full range of functionalized products, suggesting that other limitations need to be considered. One such limitation, well-documented in PTR literature, is the tendency of protonation to lead to fragmentation of some analytes. In this work, we evaluate the potential for PTR to detect dimers and the most oxygenated compounds as these have been shown to be crucial for forming atmospheric aerosol particles. We studied the detection of dimers using a Vocus PTR-TOF in laboratory experiments, as well as through quantum chemical calculations. Only noisy signals of potential dimers were observed during experiments on the ozonolysis of the monoterpene α-pinene, while a few small signals of dimeric compounds were detected during the ozonolysis of cyclohexene. During the latter experiments, we also tested varying the pressures and electric fields in the ionization region of the Vocus PTR-TOF, finding that only small improvements were possible in the relative dimer contributions. Calculations for model ROOR and ROOH systems showed that most of these peroxides should fragment partially following protonation. With the inclusion of additional energy from the ion–molecule collisions driven by the electric fields in the ionization source, computational results suggest substantial or nearly complete fragmentation of dimers. Our study thus suggests that while the improved versions of PTR-based mass spectrometers are very powerful tools for measuring hydrocarbons and their moderately oxidized products, other types of CIMS are likely more suitable for the detection of ROOR and ROOH species.

For the first time, hyperpolarized (HP) 129Xe NMR measurements are utilized to explore porous structures of porous starch (PS) successfully. Some micropores resided inside the mesopore walls of PS were detected by variable temperature (VT) HP 129Xe NMR, and the pore sizes of micropores were also estimated using the empirical relationship. Furthermore, the interconnectivity of pores was investigated in detail by two-dimensional (2D) exchange spectroscopy (EXSY). The exchange process of xenon from microporosity within pore walls to the free gas space was occurred at the mixing time of ≥12 ms at 173 K, which indicated the well interconnectivity between micropores and mesopores. This study not only exhibits a new approach for investigation of pores and hollows of PS, but also provides a better understanding of porous structures for rational design in adsorbing functional compounds.

Magnetic Fe-Cu materials were prepared by the sol-gel method and characterized by X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy equipped with Energy-Dispersive X-ray spectroscopy (SEM-EDS) and Vibrating Sample Magnetometer (VSM). These materials were applied for the removal of pyridine under the ultraviolet (UV) irradiation in the Fenton-like system. The influences of different parameters, such as the molar ratio of Fe and Cu, catalyst dosages, H2O2 dosages, initial pH value and initial pyridine concentration have been investigated. Analysis of variance (ANOVA) was applied to analyze the impacts of the key factors on the removal efficiency of TOC. The mechanism of the UV/H2O2/M-40% system was explored. The co-doped Fe-Cu catalyst showed high activity, good stability and easy recovery for the degradation of pyridine when the M-40% dosage was 0.90 g L−1, H2O2 dosage was 832.50 mg L−1, initial pH value was 7 and initial pyridine concentration was 100.00 mg L−1. The degradation efficiency of pyridine was more than 99% within 30 min and the removal efficiency of TOC was 97.36 ± 1.10% within 50 min. Therefore, the catalyst M-40% was a potential wastewater treatment material that could widen the action range of pH values, facilitating recycling and reuse.

The incorporation of oxygen vacancy defects into the catalysts has been attracting significant interest for regulating the performance of photocatalysts. Single-atomic-site metal catalysts have als...

Four novel three-dimensional interpenetrating frameworks based on {P4Mo6} units, H[C12H14N2]4[TM4(PO4)(H2O)4Na6][TM2(Mo6O12(HPO4)3(PO4)(OH)3)4]·8H2O (1, 2) and H[C14H18N2]4[TM4(PO4)(H2O)4Na6][TM2(M...

For the first time, 129Xe NMR measurements are utilized to explore adsorption mechanism between porous structures of mesoporous corn starch and Palladium. Dithiocarbamate modified mesoporous corn starch (donated as DTC MS) was synthesized and applied for adsorption of Pd (II) ion successfully. The structural characterization of DTC MS was carried out by FT-IR, 13C solid-state NMR and XRD, respectively. To study the adsorption mechanism, variable temperature 129Xe NMR was measured on samples of DTC MS and Pd adsorbed in DTC mesoporous starch (donated as Pd-DTC MS), respectively. It was found that Pd ions were mainly located inside pores and channels instead of the surface of mesoporous starch. The results not only demonstrate that 129Xe NMR spectroscopy is a powerful tool to assess the porous structure of MS, but also pave the way for investigating the interaction between functional molecules and porous starch.

This study evaluated the removal of multiple pollutants, i.e., polybrominated diphenyl ethers (PBDEs), novel halogenated flame retardants (HFRs), sulfonamide antibiotics (SAs), and heavy metals (HMs), by a full-scale reversed A2/O process in a sewage treatment plant (STP) in Guangzhou, China. The reversed A2/O process demonstrated high removal efficiencies (REs) for total PBDEs (60.5% ± 4.3%), novel HFRs (98.4% ± 2.8%) and HMs (70.1% ± 1.2%), and a relatively low RE for SAs (25.0% ± 2.3%). BDE 209, the dominant PBDE congener, showed a high residual concentration (13.41 ± 5.18 ng/L) in the suspended particulate matter (SPM) of treated effluents. Some novel HFRs, dechlorane plus (DP) and decabromodiphenyl ethane (DBDPE), were detected in the SPM of the raw sewage (7.50 ± 4.14 ng/L and 11.52 ± 11.65 ng/L, respectively). The removal of SAs was mainly through biodegradation in the activated sludge bioreactors (ASBs). Of the HMs, Mn and Ni exhibited the lowest REs (47.5% ± 2.2% and 35.0% ± 2.6%, respectively), while Cr and Cu showed the highest removal (REs > 80%). In terms of treatment units in the reversed A2/O process, ASBs showed the highest RE (27.8%) for the multiple pollutants. The information can aid in our understanding of removal properties of STPs on various pollutants and evaluating the ecological/health risks of STPs as point pollutant sources

The rational design of efficient catalysts can be guided by identifying proper descriptors that can rationalize and predict the catalytic behaviors. This study presents the feasibility of using the relative position between O p-band center and B-site metal cation d-band center as an activity descriptor for methane oxidation over LaCoO3 perovskite oxides. Experiments on B-site substituted LaFexCo1-xO3 perovskite oxides revealed that the relative positions between the two band centers governed the catalytic comportment. The suprafacial model-driven catalysts with negative relative position values exhibited exceeding activity at low temperatures; Inversely, the intrafacial model-driven catalysts with positive relative position values, showed superior activity at high temperatures. These findings were found to be effective on the A-site substituted La1-xSrxCoO3 perovskite oxides for catalytic performance prediction. This work hence showcases a promising principle to design highly active perovskite catalysts suitable for oxidation reactions. Ministry of Education (MOE) Ministry of National Development (MND) National Environmental Agency (NEA) National Research Foundation (NRF) Accepted version This work is supported by the National Research Foundation, Prime Minister’s Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of the Environment and Water Resource, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability – Integration Fund (Award No. USS-IF-2019-4), and Singapore Ministry of Education [Tier 1, Grant number RG3/18(S); Tier 2, Grant number MOE2018-T2-2-027]. Authors thank the support from Environmental Chemistry and Materials Centre (ECMC) under Nanyang Environment and Water Research Institute (NEWRI), as well as the Sustainable Earth (SE) division of the Nanyang Technological University’s Interdisciplinary Graduate School (IGS). Technical supports from the Facility for Analysis, Characterization, Testing and Simulation (FACTS) in Nanyang Technological University for materials characterizations are acknowledged. Authors also appreciate the financial support from the Nanjing Tech University Research Start-up Fund [grant number 38274017111], and 111 Project (D18023).

An efficient cascade reaction of tryptamine-derived isocyanides with C,N-cyclic azomethine imines is described. The polycyclic pyrrolo[2,3- c ]quinoline derivatives, which benefited from rearrangement process driven by hydrogen bonding, could be directly assembled in moderate to good yields (40-87%) under metal-free and mild conditions. This transformation involved four new heterocyclic rings formations and uniquely, ring opening of indole as well as ring expansion of C,N-cyclic azomethine imine. Both experimental and DFT studies provided guidance on the in-depth insight into the reaction pathways and hydrogen bonding was identified to lower the free energy barrier in transition states. This work constitutes a rare example of tryptamine-derived isocyanide-based cascade reactions, and potentially could be a powerful synthetic strategy for accessing polycyclic analogues involved in natural products.

Recently, exosomes have been extensively applied in tissue regeneration. However, their practical applications are severely restricted by the limited exosome secretion capability of cells. Therefore, developing strategies to enhance the production of exosomes and improve their biological function attracts great interest. Studies have shown that biomaterials can significantly enhance the paracrine effects of cells and exosomes are the main signal carriers of intercellular paracrine communication, thus biomaterials are considered to affect the exosome secretion of cells and their biological function. In this study, a widely recognized biomaterial, 45S5 Bioglass® (BG), is used to create a mild and cell-friendly microenvironment for mesenchymal stem cells (MSCs) with its ion products. Results showed that BG ion products can significantly improve exosome production of MSCs by upregulating the expression of neutral sphingomyelinase-2 (nSMase2) and Rab27a which enhanced the nSMases and Rab GTPases pathways, respectively. Besides, microRNA analysis indicates that BG ion products can modulate the cargoes of MSCs-derived exosomes by decreasing microRNA-342-5p level while increasing microRNA-1290 level. Subsequently, the function of exosomes is modified as their capabilities of promoting the vascularization of endothelial cells and facilitating the intradermal angiogenesis are enhanced. Taken together, BG ion products are confirmed to enhance exosome production and simultaneously improve exosome function, suggesting a feasible approach to improve the practical application of exosomes in regenerative medicine., Graphical abstract Image 1, Highlights • BG is used to create a mild and friendly microenvironment for cells to produce exosomes. • BG can significantly promote cells to release exosomes with enhanced capability of facilitating vascularization. • nSMase2 and Rab27a play crucial roles in the production of exosomes enhanced by BG.

In the paper, molecular dynamics simulation is applied to study the evolution and distribution of subsurface defects during nanoscale machining process of single-crystal copper. The chip-removal me...

The largest antimonomolybdate monomer, [Sb8MoVI13MoV5O66]5- (1-Sb8Mo18), has been isolated and displays a new breakthrough of polyoxometalates (POMs) with an ionothermal synthesis strategy. 1-Sb8Mo18 features the first hexanuclear sandwich-type polymolybdate (POMo) with an unexpected metal ring {Sb6O12} to make its debut in Sb clusters. Furthermore, 1-Sb8Mo18 exhibits a prominent catalytic activity for reducing nitrobenzene to aniline with excellent sustainability.

CsPbI2Br perovskite solar cells (PSCs) based on carbon electrodes (CEs) are considered to be low-cost and thermally stable devices. Nevertheless, the insufficient contact and energy level mismatch ...

Y3-xSmxFe5O12 (x = 0, 1, 2, 3) ferrites with pure single phase were prepared by sol-gel method. The effects of Sm3+-substitution on crystal structure and magnetic properties were systematically investigated. The Sm3+ ions substitution in Y3+ sites resulted in lattice expansion and structural distortion by changing Fe[a]-O-Fe(d) bond length and bond angle, which further modified the magnetization properties and led to the decrease of saturation magnetization by regulating super-exchange interaction between tetrahedron and octahedron sites. The relationships between complex impedance with frequency and temperature were studied, suggesting that asymmetric and depressed semicircle spectrum is owing to a non-Debye like relaxation process controlled by thermal vibration charge carriers, and the electrical conduction within grains is dominated by the charge carrier transition between Fe3+ and Fe2+ sites due to the ionization effect of oxygen vacancies. By fitting the equivalent circuits, it was found that grain boundary and grain have different contributions to complex impedance spectrum while grain boundary relaxation play the dominant role at higher temperature. The slope anomalies of relaxation frequency and conductivity were observed near the ferromagnetic transition temperature (TC) owing to the magneto-electric coupling effect, revealing that magnetic ordering has a great influence on electrical conduction. Ac conductivity analysis reveal that the main conduction mode experiences a gradual transition from a small polaron hopping model (T 550K). Moreover, the increase in conductivity is ascribed to two factors: the thermally assisted charge carrier hopping and the ionization effect of oxygen vacancy due to the incorporation of Sm ions.

Identifying highly efficient, abundant, cheap, Pt-free electrocatalysts for splitting water to produce hydrogen is critical to address the issues related to the fossil fuel consumption and environmental pollution. Nickel–copper phosphides have attracted interest as synergistic components with superior electrocatalytic activity for the hydrogen evolution reaction (HER). Herein, we report on branched heterostructures of nickel–copper phosphides (CuNi/P) grown on a 3D nickel foam (NF) substrate that were synthesized using a facile hydrothermal method and subsequent low-temperature phosphidization. These unique, branched heterostructures exhibited a strong synergetic effect between various metallic phosphides, and provided more active sites and improved the material’s electronic conductivity to produce a higher charge transfer rate. Consequently, the synthesized CuNi/P possessed superior electrocatalytic performance with a low overpotential of 99 mV at current density of 10 mA/cm2, and a low Tafel slope of 79 mV/decade for hydrogen evolution in alkaline solution. In addition, this electrocatalyst exhibited electrochemical resilience for at least 10 h, which was a good indication of its possible application for large-term water electrolysis. This reported strategy may provide a path for the development of other bimetallic phosphide materials with superior catalytic performance for the hydrogen evolution reaction.