Search

In this work, a noncoplanar terphenyl served as a building block to synthesize a novel 3,3'-substituted bipyridyl ligand (L1) which further reacted with binuclear half-sandwich units A/B, giving rise to two aesthetic 4 1 metalla-knots in high yields via a coordination-driven self-assembly strategy. Furthermore, given the inherent compactness of the 4 1 metalla-knots, it creates favorable conditions for the emergence of steric repulsion. We focused on progressively introducing nitrogen atoms featuring a lone pair of electrons (LPEs) into ligand L1 to manipulate the balance of H⋅⋅⋅H/LPEs⋅⋅⋅LPEs steric repulsion during the assembly process, ultimately achieving controlled assembly from 4 1 metalla-knots to the pseudo-Solomon link and then to molecular tweezer-like assembly facilitated by stacking interactions. All the assemblies were well characterized by solution-state NMR techniques, ESI-TOF/MS, and single-crystal X-ray diffraction. The evolutionary process of the topological architectures is equivalent to visualizing the synergistic effect of steric hindrance and stacking interactions on structural assembly, providing a new avenue for achieving the controlled synthesis of different topologies., (© 2024 Wiley-VCH GmbH.)

Compared to Pt/C, the atomic ordered Pt-based intermetallic compounds can deliver higher efficiency and reliable stability, and they are considered one of the ideal cathode catalysts for the next generation of fuel cells. This work proposed a simple ferrocene atmosphere annealing method to improve commercial Pt/C and convert Pt to L1 0 -PtFe. After further acid etching treatment, the obtained carbon-supported Pt-skin L1 0 -PtFe (Pt-skin L1 0 -PtFe/C) with superfine particle size (∼3.3 nm) not only was highly dispersed on the carbon but possesses a thin Pt skin, like the armor of L1 0 -PtFe. As excepted, the ORR activity of Pt-skin L1 0 -PtFe/C (0.375 A mg -1 ; 0.921 mA cm -2 ) is far better than that of commercial Pt/C (0.121 A mg -1 ; 0.260 mA cm -2 ), and its stability is also greatly improved. Our proposed gas-solid reaction is straightforward and has great potential in producing Pt-based intermetallic catalysts on a large scale.

Although mechanically interlocked molecules (MIMs) display unique properties and functions associated with their intricate connectivity, limited assembly strategies are available for their synthesis. Herein, we presented a synergistic assembly strategy based on coordination and noncovalent interactions (π-π stacking and CH⋯π interactions) to selectively synthesize molecular closed three-link chains ([Formula: see text] links), highly entangled figure-eight knots ([Formula: see text] knots), trefoil knot ([Formula: see text] knot), and Borromean ring ([Formula: see text] link). [Formula: see text] links can be created by the strategic assembly of nonlinear multicurved ligands incorporating a furan or phenyl group with the long binuclear half-sandwich organometallic Cp*Rh III (Cp* = η 5 -pentamethylcyclopentadienyl) clip. However, utilizing much shorter binuclear Cp*Rh III units for union with the 2,6-naphthyl-containing ligand led to a [Formula: see text] knot because of the increased π-π stacking interactions between four consecutive stacked layers and CH⋯π interactions. Weakening such π-π stacking interactions resulted in a [Formula: see text] knot. The universality of this synergistic assembly strategy for building [Formula: see text] knots was verified by utilizing a 1,5-naphthyl-containing ligand. Quantitative conversion between the [Formula: see text] knot and the simple macrocycle species was accomplished by adjusting the concentrations monitored by NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Furthermore, increasing the stiff π-conjugated area of the binuclear unit afforded molecular Borromean ring, and this topology is a topological isomer of the [Formula: see text] link. These artificial metalla-links and metalla-knots were confirmed by single-crystal X-ray diffraction, NMR and ESI-MS. The results offer a potent strategy for building higher-order MIMs and emphasize the critical role that noncovalent interactions play in creating sophisticated topologies., Competing Interests: Competing interests statement:The authors declare no competing interest.

Owing to the extremely limited structural deformation caused by the introduction of guest ions that their rigid structure can sustain, crystalline materials typically fail owing to structural collapse when utilized as electrode materials. Amorphous materials, conversely, are more resistant to volume expansion during dynamic ion transport and can introduce a lot of defects as active sites. Here, The amorphous polyaniline-coated/intercalated V 2 O 5 ·nH 2 O (PVOH) nanowires are prepared by in situ chemical oxidation combined with self-assembly strategy, which exhibited impressive electrochemical properties because of its short-range ordered crystal structure, oxygen vacancy/defect-rich, improved electronic channels, and ionic channels. Through in situ techniques, the energy storage mechanism of its Zn 2+ /H + co-storage is investigated and elucidated. Additionally, this work provides new insights and perspectives for the investigation and application of amorphous cathodes for aqueous zinc ion batteries., (© 2023 Wiley‐VCH GmbH.)

By increasing the content of Ni 3+ , the catalytic activity of nickel-based catalysts for the oxygen evolution reaction (OER), which is still problematic with current synthesis routes, can be increased. Herein, a Ni 3+ -rich of Ni 3 S 4 /FeS on FeNi Foam (Ni 3 S 4 /FeS@FNF) via anodic electrodeposition to direct obtain high valence metal ions for OER catalyst is presented. XPS showed that the introduction of Fe not only further increased the Ni 3+ concentration in Ni 3 S 4 /FeS to 95.02%, but also inhibited the dissolution of NiOOH by up to seven times. Furthermore, the OER kinetics is enhanced by the combination of the inner Ni 3 S 4 /FeS heterostructures and the electrochemically induced surface layers of oxides/hydroxides. Ni 3 S 4 /FeS@FNF shows the most excellent OER activity with a low Tafel slope of 11.2 mV dec -1 and overpotentials of 196 and 445 mV at current densities of 10 and 1400 mA cm -2 , respectively. Furthermore, the Ni 3 S 4 /FeS@FNF catalyst can be operated stably at 1500 mA cm -2 for 200 h without significant performance degradation. In conclusion, this work has significantly increased the high activity Ni 3+ content in nickel-based OER electrocatalysts through an anodic electrodeposition strategy. The preparation process is time-saving and mature, which is expected to be applied in large-scale industrialization., (© 2023 Wiley‐VCH GmbH.)

Due to their unique advantages, single atoms and clusters of transition metals are expected to achieve a breakthrough in catalytic activity, but large-scale production of active materials remains a challenge. In this work, a simple solvent-free one-step annealing method is developed and applied to construct diatomic and cluster active sites in activated carbon by utilizing the strong anchoring ability of phenanthroline to metal ions, which can be scaled for mass productions. Benefiting from the synergy between the different metals, the obtained sub-nano-bimetallic atom-cluster catalysts (FeNi AC -NC) exhibit high oxygen reduction reactions (ORR) activity (E 1/2 = 0.936 V vs. RHE) and a small ORR/oxygen evolution reaction (OER) potential gap of only 0.594 V. An in-house pouch Zn-air battery is assembled using an FeNi AC -NC catalyst, which demonstrates a stability of 1000 h, outperforming previous reports. The existence of clusters and their effects on catalytic activity is analyzed by density functional theory calculations to reveal the chemistry of nano-bimetallic atom-cluster catalysts., (© 2023 Wiley-VCH GmbH.)

Electrolytic aqueous zinc-manganese (Zn-Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn-Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn-Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn 2+ deposition reaction and induces phase and structure change of the deposited manganese oxide (Zn 2 Mn 3 O 8 ·H 2 O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm -2 after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn 2+ , and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn-Mn batteries with enhanced charging capability., (© 2024. The Author(s).)

Hydrogenated nitrogen heterocyclic compounds play a critical role in the pharmaceutical, polymer, and agrochemical industries. Recent studies on partial hydrogenation of nitrogen heterocyclic compounds have focused on costly and toxic precious metal catalysts. As an important class of main-group catalysts, frustrated Lewis pairs (FLPs) have been widely applied in catalytic hydrogenation reactions. In principle, the combination of FLPs and metal-organic framework (MOF) is anticipated to efficiently enhance the recyclability performance of FLPs; however, the previously studied MOF-FLPs showed low reactivity in the hydrogenation of N -heterocycles compounds. Herein, we offer a novel P/B type MOF-FLP catalyst that was achieved via a solvent-assisted linker incorporation approach to boost catalytic hydrogenation reactions. Using hydrogen gas under moderate pressure, the proposed P/B type MOF-FLP can serve as a highly efficient heterogeneous catalyst for selective hydrogenation of quinoline and indole to tetrahydroquinoline and indoline-type drug compounds in high yield and excellent recyclability.

Ni-based metal foam holds promise as an electrochemical water-splitting catalyst, due to its low cost, acceptable catalytic activity and superior stability. However, its catalytic activity must be improved before it can be used as an energy-saving catalyst. Here, a traditional Chinese recipe, salt-baking, was employed to surface engineering of nickel-molybdenum alloy (NiMo) foam. During salt-baking, a thin layer of FeOOH nano-flowers was assembled on the NiMo foam surface then the resultant NiMo-Fe catalytic material was evaluated for its ability to support oxygen evolution reaction (OER) activity. The NiMo-Fe foam catalyst generated an electric current density of 100 mA cm -2 that required an overpotential of only 280 mV, thus demonstrating that its performance far exceeded that of the benchmark catalyst RuO 2 (375 mV). When employed as both the anode and cathode for use in alkaline water electrolysis, the NiMo-Fe foam generated a current density (j) output that was 3.5 times greater than that of NiMo. Thus, our proposed salt-baking method is a promising simple and environmentally friendly approach for surface engineering of metal foam for designing catalysts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Hydrogen production from water electrolysis is severely restricted by the poor reaction kinetics of oxygen evolution reaction (OER). In this work, a series of two-dimensional (2D) composites MOF/Ti 3 C 2 T x (the MXene phase) were fabricated by electrostatically directed assembly and used as catalysts for OER. The obtained composite materials exhibit enhanced electrocatalytic properties, thanks to the ultrathin 2D/2D heterostructure with abundant active sites in Co2Ni-MOF and the high electronic conductivity of Ti 3 C 2 T x . Among all the catalysts, Co2Ni-MOF@MX-1 achieved the best oxygen evolution performance with the lowest Tafel slope (51.7 mV dec -1 ) and the lowest overpotential (265 mV on carbon paper) at the current density of 10 mA cm -2 . These results demonstrated that the synthesis of 2D composite materials by electrostatically directed assembly could be a feasible and promising method for the preparation of 2D heterostructure catalysts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

At present, rechargeable aqueous zinc ion batteries (RZIBs) have become a rising star and highly sought after in the field of new energy. While vanadium-based RZIBs often exhibit an anomaly of increased long-cycle capacity, which has not been explored in depth. Nevertheless, it is critical to understand this phenomenon to develop high-performance RZIBs. Therefore, this study investigated the growth mechanism of VSe 2 -based RZIBs using VSe 2 /MXene as the cathode material via in-situ and ex-situ characterization techniques and electrochemical measurements. Experimental results indicated that with the interaction/extraction of Zn 2+ /H + in the host material during cycling, an obvious oxidation reaction occurs at high voltage, and the formed vanadium oxide further reacts with Zn 2+ from the electrolyte. As a result, Zn 0.25 V 2 O 5 ·H 2 O is continuously produced and accumulated, contributing to the increasing capacity of the prepared RZIBs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Recent progress in synthetic strategies, analysis techniques, and computational modeling assist researchers to develop more active catalysts including metallic clusters to single-atom active sites (SACs). Metal coordinated N-doped carbons (M-N-C) are the most auspicious, with a large number of atomic sites, markedly performing for a series of electrochemical reactions. This perspective sums up the latest innovative and computational comprehension, while giving credit to earlier/pioneering work in carbonaceous assembly materials towards robust electrocatalytic activity for proton exchange membrane fuel cells via inclusive performance assessment of the oxygen reduction reaction (ORR). M-N x -C y are exclusively defined active sites for ORR, so there is a unique possibility to intellectually design the relatively new catalysts with much improved activity, selectivity, and durability. Moreover, some SACs structures provide better performance in fuel cells testing with long-term durability. The efforts to understand the connection in SACs based M-N x -C y moieties and how these relate to catalytic ORR performance are also conveyed. Owing to comprehensive practical application in the field, this study has covered very encouraging aspects to the current durability status of M-N-C based catalysts for fuel cells followed by degradation mechanisms such as macro-, microdegradation, catalytic poisoning, and future challenges., (© 2022 The Authors. Small published by Wiley-VCH GmbH.)

Rechargeable aqueous Zn-Mn batteries have garnered extensive attention for next-generation high-safety energy storage. However, the charge-storage chemistry of Zn-Mn batteries remains controversial. Prevailing mechanisms include conversion reaction and cation (de)intercalation in mild acid or neutral electrolytes, and a MnO 2 /Mn 2+ dissolution-deposition reaction in strong acidic electrolytes. Herein, a Zn 4 SO 4 ·(OH) 6 ·xH 2 O (ZSH)-assisted deposition-dissolution model is proposed to elucidate the reaction mechanism and capacity origin in Zn-Mn batteries based on mild acidic sulfate electrolytes. In this new model, the reversible capacity originates from a reversible conversion reaction between ZSH and Zn x MnO(OH) 2 nanosheets in which the MnO 2 initiates the formation of ZSH but contributes negligibly to the apparent capacity. The role of ZSH in this new model is confirmed by a series of operando characterizations and by constructing Zn batteries using other cathode materials (including ZSH, ZnO, MgO, and CaO). This research may refresh the understanding of the most promising Zn-Mn batteries and guide the design of high-capacity aqueous Zn batteries., (© 2022 Wiley-VCH GmbH.)

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is widely known for its multiple systems damage, especially neurocognitive deficits in children. Since their discovery, adenosine A 2A receptors (A 2A Rs) have been considered as key elements in signaling pathways mediating neurodegenerative diseases such as Huntington's and Alzheimer's, as well as cognitive function regulation. Herein, we investigated A 2A R role in cognitive impairment induced by chronic intermittent hypoxia (CIH). Mice were exposed to CIH 7 h every day for 4 weeks, and intraperitoneally injected with A 2A R agonist CGS21680 or A 2A R antagonist SCH58261 half an hour before IH exposure daily. The 8-arm radial arm maze was utilized to assess spatial memory after CIH exposures.To validate findings using pharmacology, the impact of intermittent hypoxia was investigated in A 2A R knockout mice. CIH-induced memory dysfunction was manifested by increased error rates in the radial arm maze test. The behavioral changes were associated with hippocampal pathology, neuronal apoptosis, and synaptic plasticity impairment. The stimulation of adenosine A 2A R exacerbated memory impairment with more serious neuropathological damage, attenuated long-term potentiation (LTP), syntaxin down-regulation, and increased BDNF protein. Moreover, apoptosis-promoting protein cleaved caspase-3 was upregulated while anti-apoptotic protein Bcl-2 was downregulated. Consistent with these findings, A 2A R inhibition with SCH58261 and A 2A R deletion exhibited the opposite result. Overall, these findings suggest that A 2A R plays a critical role in CIH-induced impairment of learning and memory by accelerating hippocampal neuronal apoptosis and reducing synaptic plasticity. Blockade of adenosine A 2A receptor alleviates cognitive dysfunction after chronic exposure to intermittent hypoxia in mice., (Copyright © 2021. Published by Elsevier Inc.)

Designing and building unique cage assemblies attract increasing interest from supramolecular chemists but remain synthetically challenging. Herein, we propose the use of a flexible vertex with adjustable angles to selectively form highly distorted tetrahedral and octahedral cages, for the first time, in which the flexible vertex forms from the synergistic effect of coordination and covalent interactions. The inherent interligand angle of the vertex can be modulated by guest anions present, which allows for the fine-tuning of different cage geometries. Furthermore, the reversible structural transformation between tetrahedral and octahedral cages was achieved by anion exchange monitored by mass spectrometric technique, the smaller anions favoring tetrahedral cages, while the larger anions supporting octahedral cages. Additionally, the KBr-based cage thin films exhibited prominent enhancement of their third-order NLO responses in two or three orders of magnitude compared to those obtained for their corresponding solutions. This work not only provides a new methodology to build irregular polyhedral structures in a controlled and tunable way but also provides access to new kinds of promising functional optical materials., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2022 Shu-Jin Bao et al.)

The practical application of room-temperature Na-S batteries is hindered by the low sulfur utilization, inadequate rate capability and poor cycling performance. To circumvent these issues, here, we propose an electrocatalyst composite material comprising of N-doped nanocarbon and Fe 3 N. The multilayered porous network of the carbon accommodates large amounts of sulfur, decreases the detrimental effect of volume expansion, and stabilizes the electrodes structure during cycling. Experimental and theoretical results testify the Fe 3 N affinity to sodium polysulfides via Na-N and Fe-S bonds, leading to strong adsorption and fast dissociation of sodium polysulfides. With a sulfur content of 85 wt.%, the positive electrode tested at room-temperature in non-aqueous Na metal coin cell configuration delivers a reversible capacity of about 1165 mA h g -1 at 167.5 mA g -1 , satisfactory rate capability and stable capacity of about 696 mA h g -1 for 2800 cycles at 8375 mA g -1 ., (© 2021. The Author(s).)

Rechargeable aqueous Zn/MnO 2 batteries show great potential for grid-scale storage due to their low cost, high safety, and energy density, yet suffer from continuous capacity decay during operation. Therefore, this work proposes a capacity self-healing aqueous Zn/MnO 2 (Zn/cCNTs-MnO 2 ) battery using carboxyl-modified carbon nanotubes (cCNTs) as the cathode substrate, ZnSO 4  + MnSO 4 mixed aqueous solution as the electrolyte, and Zn foil as the anode. Based on the controllable electrodeposition reaction of MnO 2 , the specific capacity of Zn/cCNTs-MnO 2 batteries can be achieved or recovered by operating several cycles under a low current density (0.1 mA cm -2 ). Then, the batteries can stably perform under a high current density (1 mA cm -2 ). By repeating the above steps, a capacity self-healing usage scheme was established, which can significantly improve the cycling performance of Zn/cCNTs-MnO 2 batteries. Moreover, the results of the proposed Zn/cCNTs-MnO 2 batteries verify the MnO 2 electrodeposition mechanism and introduce a novel method for the development of durable aqueous rechargeable Zn/MnO 2 batteries., Competing Interests: Declaration of Competing Interest The author declare that there is no conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the accuracy of static computer-navigated implantation with surgical guides, based on a non-radiological method. Traditional measurements with a second cone-beam CT (CBCT) were applied to verify the accuracy., Methods: A total of thirty template-guided implantations were designed and performed on 15 resin models. Two paralleled bone-level implants were planned in the edentulous space of each model, between which the distance was 4 mm. Postoperative implant positions were detected with both CAD/CAM-based measurements applying an intraoral scanner (3Shape TRIOS) and traditional ways via CBCT. Both methods were conducted with a CAD quality-control, reverse engineering software, Geomagic Studio 2013, comparing the positions with the virtual ones. Statistical analysis was processed with SPSS 23.0 software package., Results: Measurements using CBCT (control group) showed a trend toward greater deviations when the results were directly compared(P<0.05). In the CAD/CAM-based evaluation of the 30 samples, the mean deviation of the insertion axis from the planned implant axis was 1.134°. The mean deviations of the implant shoulders in the horizontal direction and at the implant apices were 0.447 mm and 0.557 mm, respectively. No significant difference was observed when measuring distance deviation with the two assessment ways., Conclusions: Compared with evaluation based on radiology, CAD/CAM based evaluation system is able to evaluate implant accuracy precisely, effectively reduce radiological exposure of patients, being suitable for clinical evaluation.

Reactions of (NH 4 ) 2 WS 4 with CuCN, CuCN/1,2-bis(4-pyridyl)propane (bppa) or [Cu(MeCN) 4 ]PF 6 /bppa under different reaction conditions afforded a set of two- or three-dimensional W/Cu/S cluster-based coordination polymers including {[Et 4 N] 2 [WS 4 Cu 4 (μ-CN) 2 (μ-I) 2 ]} n (1), [WS 4 Cu 4 (μ-CN) 2 (bppa) 2 ] n (2) and {[WS 4 Cu 4 (bppa) 4 ](PF 6 ) 2 } n (3), respectively. Compound 2 can be readily formed from reaction of 1 with bppa under solvothermal conditions. Compounds 1 and 2 feature two-dimensional networks with a "sql" topology, while 3 possesses a two-fold interpenetrated three-dimensional net with a rare "reo" topology. Compounds 1-3 in DMF exhibited different third-order nonlinear optical responses, and they all showed a reverse saturable absorption while 2 held a strong self-focusing effect., (© 2021 Wiley-VCH GmbH.)

Enzymes have demonstrated great potential in the development of advanced electroanalysis devices due to their unique recognition and catalytic properties. However, unsatisfactory stability and limited electron communication of traditional enzyme sensors seriously hinder their large-scale application. In this work, a simple and effective method is proposed to improve the stability of enzyme sensors by using sodium hyaluronate (SH) as a protective film, MXene-Ti 3 C 2 /Glucose oxidase (GOD) as the reaction layer, and chitosan (CS) /reduced graphene oxide (rGO) as the adhesion layer. Results demonstrate that the repeatability of the designed sensor increased by 73.3% after improving the adhesion between the reaction layer and the current collector and that its response ability was greatly enhanced. Moreover, the long-term stability of the electrode surface with SH protective film proved to be superior than that without protective film, which suggests that this design can effectively improve the overall performance of the enzyme biosensor. This work proposed a multi-tier synergistic approach for improving the reliability of enzyme sensors. Graphical abstract Our proposed protective and adhesion layer can greatly improve the stability of enzyme sensor and realize the rapid detection of glucose in serum sample., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

In this work, controlled-size hollow polyhedron assembled by crumpled nickel hydroxide (Ni(OH) 2 ) nanosheets from silicon dioxide (SiO 2 )-covered zeolitic imidazole framework-67 (ZIF-67@SiO 2 ) is prepared via a template-sacrificed method. It is found that SiO 2 plays an essential role in keeping intact polyhedrons and suppressing particle growth. Benefiting from structural and compositional advantages, the Ni(OH) 2 @S electrode exhibits high specific capacity, excellent rate performance, and stable cycle life at 1C with a small capacity decay of 0.067% per cycle. The Ni(OH) 2 hollow polyhedrons can accommodate the volume expansion to maintain the integrity of the electrode and suppress the shuttling effect of polysulfides via abundant hydroxyl groups. Hence, this strategy is beneficial to anticipate the material for large-scale applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Room-temperature (RT) sodium-sulfur batteries hold great promise for the development of efficient, low-cost, and environmentally friendly energy storage systems. Nevertheless, the dissolution of long-chain polysulfides is a huge obstacle. In this work, a composite cathode which integrates Ni/Co bimetal nanoparticles as the catalyst and carbon spheres with abundant channels as the host is prepared for RT Na-S batteries. Moreover, a valuable strategy to reduce the dissolution of polysulfides by accurately regulating the two-step reaction kinetics of polysulfide transformation (from Na 2 S to long-chain polysulfides and then from polysulfides to sulfur) is presented. Through adjusting the ratio of Ni and Co, the optimal cathode with a Ni/Co ratio of 1:2 can retard the first conversion of Na 2 S to polysulfides and simultaneously accelerate the subsequent transformation of polysulfides to sulfur. In this case, the soluble polysulfides can immediately transform to solid sulfur as soon as it appears, thus avoiding the shuttle of polysulfides. The galvanostatic intermittent titration method and in situ Raman are employed to supervise the transformation of polysulfides during the discharge/charge process. As a result, the composite shows excellent performance as the cathode of RT liquid/quasi-solid-state Na-S batteries in terms of specific capacities, rate capability, and cycle stability.

Purpose: Using impact test to study cushioning and energy absorption of sports mouthguard of different thickness, material and combination., Methods: According to the thickness, material and combination, the mouthguards were divided into 7 groups with 6 testing pieces in each group. A pendulum device was used to apply impact energy to the mouthguard and dentition model, and the magnitude of the impact energy was measured by changing the release height of the pendulum. The force sensor and the laser vibrometer were respectively connected to the data acquisition and signal analyzer to obtain the incident speed, rebound speed, maximum collision force, collision start time and collision end time of the hammer head. Collision time, energy absorption and energy absorption ratio of the mouthguard were calculated, which reflected different mouthguard cushioning and energy absorption characteristics. One-way analysis of variance and t test in SPSS 22.0 software package was used to analyze the difference between different groups., Results: No matter what type of mouthguard was worn by the dentition model, the impact force was significantly reduced than without mouthguards. At the same height, there was significant difference between the average maximum collision force and the average collision time among soft mouthguards with thicknesses of 2, 3, 4, and 5 mm(P<0.05); among which the average maximum collision force of the 5 mm was the smallest and the average collision time was the shortest. There was no significant difference in the average energy absorption and the average energy absorption ratio among these 4 groups. There was significant difference in the average maximum collision force, average collision time, average energy absorption and average energy absorption ratio between the two groups of mouthguards with the same thickness of splints and different materials(P<0.05). Among them, the average maximum impact force of the 4 mm soft mouthguard was smaller and the average collision time was longer., Conclusions: Wearing sports mouthguard can reduce the risk of tooth fracture during collision. Soft mouthguard has the best cushioning performance and it is positively related to thickness. Locally strengthening hard materials can enhance energy absorption and provide better protection.

Quasi-solid-state potassium-ion batteries (QSPIBs) are regarded as one of the most promising safety-enhanced energy storage devices. Herein, a facile method for preparing a potassium-ion composite electrolyte membrane on a large scale is presented for the first time. The as-synthesized membrane displays excellent electrochemical stability, good mechanical flexibility, and high ionic conductivity (9.31 × 10 -5 S cm -1 at 25 °C). Furthermore, QSPIBs prepared with this membrane and commercial raw material-based electrodes show superior electrochemical performance even at low temperatures (99.7 mAh g -1 at -20 °C for half QSPIBs and 90.7 mAh g -1 at -15 °C for full QSPIBs), and a promising rate performance (115.6 mAh g -1 for half QSPIBs and 90.9 mAh g -1 for full QSPIBs at 800 mA g -1 ). The reaction mechanism and structure evolution of a 3,4,9,10-perylene-tetracarboxylicacid-dianhydride (PTCDA) cathode is also systematically studied. The promising characteristics of the prepared low-cost quasi-solid-state potassium-ion batteries in this work open up new possibilities for safer and more durable batteries and a wide range of practical applications in the electronics industry., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Rechargeable room temperature sodium-sulfur (RT Na-S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D "branch-leaf" biomimetic design proposed for high performance Na-S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive "branches" to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D "branch-leaf" conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co-S-Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared "branch-leaf" CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g -1 at 0.1 C and superior rate performance.

Electrochemical in situ sensing of small signal molecules released from living cells has an increasing significance in early diagnosis, pathological analyses, and drug discovery. Here, a living cell-fixed sensing platform was built using the BC@DNA-Mn 3 (PO 4 ) 2 nanozyme, in which a highly biocompatible bacterial cellulose riveted with very tiny Mn 3 (PO 4 ) 2 ; it not only delivers high catalytic activity toward superoxide anions but possesses excellent biocompatibility for cell adsorption and growth. Additionally, the experimental results suggested that fixing the living cells on the surface of the sensing platform facilitates tiny Mn 3 (PO 4 ) 2 activity centers to capture and detect O 2 •- very quickly and simultaneously has great potential in miniaturization, cost reduction, and real-time monitoring.

Influenza is an acute respiratory infection caused by the influenza virus, and vaccination against influenza is considered the best way to prevent the onset and spread. MDCK (Madin-Darby canine kidney) cells are typically used to isolate the influenza virus, however, their high tumorigenicity is the main controversy in the production of influenza vaccines. Here, MDCK-C09 and MDCK-C35 monoclonal cell lines were established, which were proven to be low in tumorigenicity. RNA-seq of MDCK-C09, MDCK-C35, and MDCK-W73 cells was performed to investigate the putative tumorigenicity mechanisms. Tumor-related molecular interaction analysis of the differentially expressed genes indicates that hub genes, such as CUL3 and EGFR, may play essential roles in tumorigenicity differences between MDCK-C (MDCK-C09 and MDCK-C35) and MDCK-W (MDCK-W73) cells. Moreover, the analysis of cell proliferation regulation-associated molecular interaction shows that downregulated JUN and MYC, for instance, mediate increased proliferation of these cells. The present study provides a new low-tumorigenic MDCK cell line and describes the potential molecular mechanism for the low tumorigenicity and high proliferation rate., (Copyright © 2020. Published by Elsevier Ltd.)

Sodium sulfur batteries require efficient sulfur hosts that can capture soluble polysulfides and enable fast reduction kinetics. Herein, we design hollow, polar and catalytic bipyramid prisms of cobalt sulfide as efficient sulfur host for sodium sulfur batteries. Cobalt sulfide has interwoven surfaces with wide internal spaces that can accommodate sodium polysulfides and withstand volumetric expansion. Furthermore, results from in/ex-situ characterization techniques and density functional theory calculations support the significance of the polar and catalytic properties of cobalt sulfide as hosts for soluble sodium polysulfides that reduce the shuttle effect and display excellent electrochemical performance. The polar catalytic bipyramid prisms sulfur@cobalt sulfide composite exhibits a high capacity of 755 mAh g -1 in the second discharge and 675 mAh g -1 after 800 charge/discharge cycles, with an ultralow capacity decay rate of 0.0126 % at a high current density of 0.5 C. Additionally, at a high mass loading of 9.1 mg cm -2 , sulfur@cobalt sulfide shows high capacity of 545 mAh g -1 at a current density of 0.5 C. This study demonstrates a hollow, polar, and catalytic sulfur host with a unique structure that can capture sodium polysulfides and speed up the reduction reaction of long chain sodium polysulfides to solid small chain polysulfides, which results in excellent electrochemical performance for sodium-sulfur batteries.

Room-temperature sodium/sulfur battery has raised concern due to the superiority of high theoretical capacity and low cost that promise for large-scale application. However, the sluggish electrochemical activity and "shuttle effect" limits the progress of practical application. This work designs a template method for constructing metal/carbon sulfur host, which possesses metal (Co, Ni) nanoparticles highly distributed in large amounts of porous channels in carbon sphere. The metal nanoparticles assist in sulfur immobilization, electric conductivity and catalyze reaction kinetics, meanwhile the hollow channels can buffer the volume change of sulfur. When testing as the liquid/solid-state room-temperature Na/S batteries, the S@Co/C and S@Ni/C electrodes deliver high capacities and rate capability. This template method possesses utility potential in developing high-powered RT Na/S batteries, which provides possibility to for the preparation of various electrode materials in battery technology., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Discovering and constructing novel and fancy structures is the goal of many supramolecular chemists. In this work, we propose an assembly strategy based on the synergistic effect of coordination and covalent interactions to construct a set of octahedral supramolecular cages and adjust their degree of distortion. Our strategy innovatively utilizes the addition of sulfur atoms of a metal sulfide synthon, [Et 4 N][Tp*WS 3 ] ( A ), to an alkynyl group of a pyridine-containing linker, resulting in a novel vertex with low symmetry, and of Cu(I) ions. By adjusting the length of the linker and the position of the reactive alkynyl group, the control of the deformation degree of the octahedral cages can be realized. These supramolecular cages exhibit enhanced third-order nonlinear optical (NLO) responses. The results offer a powerful strategy to construct novel distorted cage structures as well as control the degree of distortion of supramolecular geometries.

Room-temperature sodium-sulfur (RT Na-S) batteries are seriously limited because of poor conductivity of sulfur and sluggish reaction kinetics of polysulfide intermediates. Here, we design a free-standing film, constructed from Co nanoparticles onto nitrogen-doped porous carbon nanofibers (Co@NPCNFs), to load sulfur for RT Na-S batteries. Experiment result shows that Co as catalyst can enable the rapid sodium intercalation and fast reduction reaction of the polysulfides during cycling. Hence, the prepared Co@NPCNFs/S cathode exhibits a remarkable capacity of 906 mAh g -1 at 0.1 C and long cycling life up to 800 cycles with a slow capacity decay of 0.038% per cycle at 1 C., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The high energy density of room temperature (RT) sodium-sulfur batteries (Na-S) usually rely on the efficient conversion of polysulfide to sodium sulfide during discharging and sulfur recovery during charging, which is the rate-determining step in the electrochemical reaction process of Na-S batteries. In this work, a 3D network (Ni-NCFs) host composed by nitrogen-doped carbon fibers (NCFs) and Ni hollow spheres is synthesized by electrospinning. In this novel design, each Ni hollow unit not only can buffer the volume fluctuation of S during cycling, but also can improve the conductivity of the cathode along the carbon fibers. Meanwhile, the result reveals that a small amount of Ni is polarized during the sulfur-loading process forming a polar Ni-S bond. Furthermore, combining with the nitrogen-doped carbon fibers, the Ni-NCFs composite can effectively adsorb soluble polysulfide intermediate, which further facilitates the catalysis of the Ni unit for the redox of sodium polysulfide. In addition, the in situ Raman is employed to supervise the variation of polysulfide during the charging and discharging process. As expected, the freestanding S@Ni-NCFs cathode exhibits outstanding rate capability and excellent cycle performance., Competing Interests: The authors declare no conflict of interest., (© 2019 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

Inspired by the structure of puzzles, bombyx mori silk-derived carbon dots (CDs) with abundant negative groups, as jigsaw pieces, were combined with nano-CoP to create a highly effective electrocatalytic interface. The hollow cavity and thin wall of the bamboo-like CDs/CoP nanoarray is beneficial to produce more H˙ radicals and accelerate water decomposition.

A corn-like CeO 2 /C coaxial cable textured by a cerium oxide shell and a carbon core was designed to sense NO. The carbon core possesses high electrical conductivity, and the CeO 2 surface delivers excellent electrocatalytic activity. The sensor, typically operated at 0.8 V (vs. Ag/AgCl), exhibits a detection limit of 1.7 nM, which is 4-times lower than that of CeO 2 nanotubes based one (at S/N = 3). It also displays wide linear response (up to 83 μM), a sensitivity of 0.81 μA μM -1  cm -2 , and fast response (2 s). These values are highly competitive to that of a CeO 2 tube (0.92 μA μM -1  cm -2 and 2 s). The sensor was used to quantify NO that is released by Aspergillus flavus. Graphical abstractSchematic representation of corn-like CeO 2 /C which can more sensitively and effectively detect NO released from A. flavus than when using CeO 2 nanotubes, benefitting from its unique coaxial cable structure.

Sodium-ion capacitors (SICs) have shown great potential to combine the merits of high-power capability of traditional capacitors and high energy capability of batteries. However, the sluggish kinetics and inferior stability of conventional sodium-ion storage anode materials are major challenges for the practical utilization of SICs. In this work, interconnected urchin-like hollow Na 2 Ti 3 O 7 (Na 2 Ti 3 O 7 -IcUH) chains were designed and prepared by a simple one-step template-assisting method. Through a variety of controlled experiments, we explored how to effectively engineer the crystal-oriented growth and string the urchin-like spheres together. Benefiting from its urchin-like hollow structure and fully exposed (001) facet, the resulting Na 2 Ti 3 O 7 -IcUH exhibits a superior rate capability of 96.2 mA h g -1 at 5 A g -1 . Meanwhile, the interconnected three-dimensional primary structure endows Na 2 Ti 3 O 7 -IcUH with excellent cyclic stability (15% capacity loss at 5 A g -1 after 2000 cycles). By coupling with commercial active carbon, the assembled SIC successfully demonstrates a energy density of 134.3 W h kg -1 at a power density of 125 W kg -1 and 38.2 W h kg -1 at a high-power density of 2500 W kg -1 , as well as a superior capacity retention of 75% after 2000 cycles at 2 A g -1 within 1-4 V.

Theranostic nanoplatforms that integrate therapy and diagnosis in a single composite have become increasingly attractive in the field of precise and efficient tumor treatment. Herein, a novel oxygen-deficient zirconia (ZrO 2- x ) nanosystem based on the conjugation of thiol-polyethylene glycol-amine (SH-PEG-NH 2 ) and chlorin e6 (Ce6) was elaborately designed and established for efficacious photothermal/photodynamic therapy (PTT/PDT) and fluorescence/photoacoustic (FL/PA) bimodal imaging for the first time. The crystalline-disordered, PEGylated ZrO 2- x nanoparticles (ZP NPs) displayed strong optical absorption in the near-infrared (NIR) window and were featured with significant photothermal conversion capacity. The ZP NPs were further covalently conjugated with Ce6 to form ZrO 2- x @PEG/Ce6 (ZPC) NPs, which displayed a long circulatory half-life, efficient tumor accumulation, and outstanding FL/PA imaging performance. Moreover, the nanocomposites effectively generated cytotoxic intracellular reactive oxygen species (ROS) responsive to laser activation. Both cell studies and animal experiments explicitly demonstrated that ZPC NPs mediated remarkable tumor ablation with minimal systemic toxicity thanks to their tumor-specific PTT/PDT effect. Collectively, these findings may open up new avenues to broaden the application of oxygen-deficient ZrO 2- x nanostructures as high-performance photothermal agents in tumor theranostics through rational design and accurate control of their physiochemical properties.

Purpose: Using impact test to study energy absorption ability of mouthguard splints of different thickness and materials., Methods: In this experiment, group 1 was BIOPLAST 5 mm splint, group 2 was BIOPLAST 4 mm splint, group 3 was BIOPLAST 3 mm splint，group 4 was BIOPLAST 2 mm splint and group 7 was BIOPLAST 1 mm splint. Group 5 was ERKOLOC-PRO 2 mm splint, group 6 was DURAN 2 mm splint. Mouthguard splints were clashed by impact head from different heights. Digital Image Correlation System was used to record the process of the test. Images were transferred to data processing software, to analyze incident speed, incident depth and rebound height of the impact head. Absorbed energy and energy absorption ratio were calculated to analyze energy absorption ability of mouthguard splints of different thickness and materials. The data were analyzed using SPSS 22.0 software package for one-way analysis of variance and LSD., Results: The higher impact head fell, the larger energy absorption ratio was. There was significant difference among group 1, 2, 3, 4, 7 in average energy absorption ratio（P<0.05）, and group 7 was the largest. There was significant difference among group 4, 5, 6 in average energy absorption ratio（P<0.05）, among which group 4 and group 5 were larger., Conclusions: 3 mm splint is good enough to be used to make mouthguard, which is also thinner and more comfortable. Splint of soft material is more suitable for mouthguard than splint of hard material.

Room-temperature Na-S batteries are facing one of the most serious challenges of charge/discharge with long cycling stability due to the severe shuttle effect and volume expansion. Herein, a sodium polysulfides defense system is presented by designing and constructing the cathode-separator double barriers. In this strategy, the hollow carbon spheres are decorated with MoS 2 (HCS/MoS 2 ) as the S carrier (S@HCS/MoS 2 ). Meanwhile, the HCS/MoS 2 composite is uniformly coated on the surface of the glass fiber as the separator. During the discharge process, the MoS 2 can adsorb soluble polysulfides (NaPSs) intermediates and the hollow carbon spheres can improve the conductivity of S as well as act as the reservoir for electrolyte and NaPSs, inhibiting them from entering the anode to make Na deteriorate. As a result, the cathode-separator group applied to room-temperature Na-S battery can enable a capacity of ≈1309 mAh g -1 at 0.1 C and long cycling life up to 1000 cycles at 1 C. This study provides a novel and effective way to develop durable room-temperature Na-S batteries., Competing Interests: The authors declare no conflict of interest., (© 2019 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

Since the oxygen evolution catalysis process is vital yet arduous in energy conversion and storage devices, it is highly desirous but extremely challenging to engineer earth-abundant, noble-metal-free nanomaterials with superior electrocatalytic activity toward effective oxygen evolution reactions (OERs). Herein, we construct a prismlike cobalt-iron layered double hydroxide (Co-Fe LDH) with a Co/Fe ratio of 3:1 utilizing a facile self-templated strategy. Instead of carbon-species-coupled treatment, we focus on ameliorating the intrinsic properties of LDHs as OER electrocatalysts accompanied by the hierarchical nanoflake shell, well-defined interior cavity, and numerous microporous defects. In contrary to conventional LDHs synthesized via a one-pot method, Co-Fe LDHs fabricated in this work possess a huge specific surface area up to 294.1 m 2 g -1 , which not only provides abundant active sites but also expedites the kinetics of the OER process. The as-prepared Co-Fe LDH electrocatalysts exhibit advanced electrocatalytic performance and a dramatic stability of the OER in an alkaline environment. In particular, the contribution of micropore defects is clearly discussed according to the electrochemical impedance spectroscopy analysis, in which the time constant of the OER at the micropore defect is several orders of magnitude smaller than that at the exterior of Co-Fe LDHs, forcefully verifying the intrinsic catalytic activity enhancement derived from the micropore defects. This work provides a promising model to improve OER electrocatalyst activity via produce defects and research the contribution of micropore defects.

The volume expansion of sulfur and the dissolution of polysulfides into the electrolyte are the key issues to be solved in the development of lithium-sulfur batteries. In this work, a labyrinth electrode material design is presented to overcome these difficulties in lithium-sulfur batteries. The shell of NiO-Co3O4 hollow spheres as the "wall" to prevent the polysulfide dissolution cross-links into a labyrinth network as a sulfur host. The 3D labyrinth network not only provides enough inner space to load sulfur but also adapts to its large volume expansion during lithiation and delithiation. In addition, the polar NiO-Co3O4 shells can promote the chemical adsorption of polysulfides, while NiO-Co3O4 shells can promote the conversion of polysulfides into Li2S. With this unique design, the 3D labyrinth-like NiO-Co3O4@S electrode presents a good electrochemical performance, delivering high capacity with a stable cycling life of up to 200 cycles at 1C and the attenuation rate of each cycle is only 0.1%.

During the development of oxygen reduction reaction electrocatalysts, transition-metal nanoparticles embedded in N-doped graphene have attracted increasing attention owing to their low-priced, minimal environmental impact, and satisfying performance. In this study, a new organic-cadmium (Cd) complex formed through Cd 2+ coordination with p-phenylenediamine (PPD) was used to synthesize highly active Fe-embedded N-doped carbon catalysts for the first time. It is significant that with the decreasing molar ratio of Cd/Fe, an obvious microstructure evolution was observed in Cd-Fe-PPD from diamond-like blocks to thick flakes, and further bloomed into flowerlike shapes with ultrathin petals and then eventually exhibited large block starfish-like shapes. After carbonization, Cd was removed, slack and porous N-doped carbon was formed, and Fe was assembled in the N-doped carbon. Similar phenomenon was also observed in Co-PPD. The optimized Fe/NPC-2 material featuring uniform and well-dispersed 3-5 nm Fe nanoparticles embedded in two-dimensional ultrathin carbon nanosheets delivered excellent electrocatalytic performance ( E onset : 0.96 V vs reversible hydrogen electrode (RHE), E 1/2 : 0.84 V vs RHE), which is very close to those of commercial platinum on carbon (Pt/C) ( E onset : 0.95 V vs RHE, E 1/2 : 0.84 V vs RHE), and its methanol tolerance and durability also surpass those of Pt/C.

Purpose: To investigate the effect of tooth movement at different time after repair of alveolar bone defects with tissue engineering bone constructed by rabbit bone marrow mesenchymal stem cells (BMSCs) and beta-tricalcium phosphate (β-TCP)., Methods: Alveolar bone defect (6 mm×4 mm×8 mm) was made on the right side of 40 New Zealand rabbits, which was filled with tissue engineering bone constructed by BMSCs and β-TCP as experimental sides. Tooth extraction on the other side was performed as control. The mandibular second molars in both sides were moved mesially 2, 4, 8 and 12 weeks after surgery. The specimens were taken 4 weeks after exertion. The distance of mandibular second molar moved was measured. The periodontal tissues were observed after H-E staining. TRAP staining was performed and osteoclasts were counted in the periodontal tissues on the pressure side. BMP-2 immunohistochemical staining was used to observe the average optical density of periodontal tissue on tension side. The results were analyzed with SAS 8.0 software package., Results: The distance of tooth movement, the amount of TRAP positive cells and the optical density of BMP-2 in the experimental side of the 2-week and 4-week groups were all significantly lower than those in the control side, while there was no significant difference between the 8-week and 12-week groups., Conclusions: Eight weeks after repair of alveolar bone defect with rabbit BMSCs and β-TCP is an appropriate time for orthodontic tooth movement.

Monitoring superoxide anions in living cells have attracted much academic and biomedical interest due to their important role in metabolic processes. Herein, we confined ultra-small nano-Mn 3 (PO 4 ) 2 in chitosan and designed a unique puffy woven sphere consisted by nanowires. Further constructed an effective in situ detection chip using the as-synthesized nano-Mn 3 (PO 4 ) 2 -chitosan for electrochemical sensing of superoxide anions from murine breast tumor cells (4T1). The excellent biocompatibility of chitosan and large size of the Mn 3 (PO 4 ) 2 -chitosan spheres greatly reduced the damage and toxicity of the detection interface to the living cells, while the ultra-small nano-Mn 3 (PO 4 ) 2 in chitosan could effectively catalyze the superoxide anions released from cells. The nano-Mn 3 (PO 4 ) 2 -chitosan-based sensor exhibited high sensitivity (1.6 μA μM -1 ), low detection limit (9.4 nM at S/N = 3) and good selectivity for O 2 •- . After cell culture on the surface of nano-Mn 3 (PO 4 ) 2 -chitosan based electrode. As a miniature analytical and sensing platform, results further suggest that the prepared chip offers a more sensitive detective superoxide anions (O 2 •- ) released from 4T1 cell lines than traditional electron paramagnetic resonance (EPR) analysis., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: This study aimed to use cone-beam computed tomography (CBCT) to evaluate the root anatomy and canal morphology of maxillary premolars in a Chinese population and determine their degree of bilateral symmetry., Design: 774 CBCT images were retrospectively analyzed, representing 1387 maxillary first premolars and 1403 second premolars. The number of roots and canals were recorded. The morphology of root canal systems was determined according to Vertucci's classification. The symmetry of root and canal anatomies between maxillary contralateral premolars was further evaluated., Results: The most common anatomy of maxillary first and second premolars was one-rooted with two canals (58.0%) and one-rooted with one canal (50.3%), respectively. The typical canal morphology was type IV (42.7%) in maxillary first premolars and type I (50.3%) in maxillary second premolars. One-rooted maxillary premolars exhibited a higher variability in the canal morphology, compared to two-rooted or three-rooted teeth. Maxillary second premolars exhibited greater anatomic symmetry than first premolars. The root and canal numbers showed bilateral symmetry between 80.2% of maxillary first premolar pairs and 81.8% of second premolar pairs. Bilateral symmetry in both number and morphology of roots and canals was observed for 72.3% of maxillary first premolar pairs and 73.2% of second premolar pairs., Conclusion: The root anatomy and canal morphology of maxillary premolars in a Chinese population were quite diversified. Maxillary contralateral premolars demonstrated a high degree of symmetry in root and canal anatomies, which enables practitioners to better determine the nature of the root canal system during treatment of opposite homonymous teeth., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose: To explore periodontal responses on the compression side during early tooth movement into alveolar defect regenerated by bone marrow mesenchymal stem cells (BMSCs) and porous granulated beta-tricalcium phosphate（β-TCP） scaffolds., Methods: Thirty New Zealand rabbits were used to establish bilateral mandibular defective alveolar bone model by extracting the mandibular first molars and expanding the sockets. The right mandibular alveolar defects were filled with a construct of β-TCP scaffolds combined with BMSCs as experimental group. The left alveolar defects were repaired by β-TCP scaffolds alone as control group. Eight weeks later, 6 rabbits were sacrificed to evaluate osteogenesis effect. The other rabbits were loaded orthodontic force to move the bilateral second molars forward for 4 weeks. Six rabbits in each group were sacrificed at 1, 2, 3, and 4 week after orthodontic tooth movement (OTM). The distance of OTM was measured, and the status of periodontal tissues was observed by H-E staining. The number of osteoclasts on the compression side of tooth was counted by tartrate-resistant acid phosphatase histochemistry. The results were compared between groups using SPSS 19.0 software package., Results: After 8 weeks of bone grafting, the osteogenesis effect of the experimental group was better than the control group. The OTM distance in the experimental area was higher than that in the control area. At 2, 3 and 4 week of OTM, the number of osteoclasts in the experimental group was significantly higher than that in the control group., Conclusions: A tissue-engineered complex with β-TCP scaffolds and BMSCs could well repair the alveolar bone defect. When the adjacent tooth moved into regenerated area, the new periodontal tissue had an active response, promoting to accelerate tooth movement.

Transition-metal phosphides (TMPs) have emerged as promising catalyst candidates for the hydrogen evolution reaction (HER). Although numerous methods have been investigated to obtain TMPs, most rely on traditional synthetic methods that produce materials that are inherently deficient with respect to electrical conductivity. An electrospinning-based reduction approach is presented, which generates nickel phosphide nanoparticles in N-doped porous carbon nanofibers (Ni 2 P@NPCNFs) in situ. Ni 2 P nanoparticles are protected from irreversible fusion and aggregation in subsequent high-temperature pyrolysis. The resistivity of Ni 2 P@NPCNFs (5.34 Ω cm) is greatly decreased by 10 4 times compared to Ni 2 P (>10 4  Ω cm) because N-doped carbon NFs are incorporated. As an electrocatalyst for HER, Ni 2 P@NPCNFs reveal remarkable performance compared to other previously reported catalysts in acidic media. Additionally, it offers excellent catalytic ability and durability in both neutral and basic media. Encouraged by the excellent electrocatalytic performance of Ni 2 P@NPCNFs, a series of pea-like M x P@NPCNFs, including Fe 2 P@NPCNFs, Co 2 P@NPCNFs, and Cu 3 P@NPCNFs, were synthesized by the same method. Detailed characterization suggests that the newly developed method could render combinations of ultrafine metal phosphides with porous carbon accessible; thereby, extending opportunities in electrocatalytic applications., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

FePO 4 is biocompatible and can act as a kind of promising enzyme mimetic. Unfortunately, the electrical conductivity of FePO 4 is poor. In order to enhance its conductivity, FePO 4 was embedded into nanofibers consisting of amorphous carbon and reduced graphene oxide (rGO) by an electrospinning technique. As a sensing material for monitoring superoxide anion (O 2 •- ) and typically operated at 0.5 V (vs. SCE), it displays high sensitivity (9.6 μA⋅μM -1 ⋅cm -2 ), a low detection limit (9.7 nM at S/N = 3), a wide linear response range (10 nM to 10 μM), and fast response (1.6 s). Due to its low detection limit and fast response, the sensor in our perception has a large potential for detecting superoxide anions released by HeLa cancer cells. Graphical abstract Schematic of the microstructure of FePO 4 /C and FePO 4 /rGO-C nanofibers, a photograph of cancer cells (HeLa), and the electrochemical response towards O 2 -• of the sensor.

In this work, we reported a novel and slack rose-like metal organic precursor designed by coordinating p-phenylenediamine with cobalt ion. After subsequent pyrolysis and acid etching process, the as-prepared Co-N-C catalyst delivered a superior catalytic activity and long-term durability. Further applied in the Zn-air battery, it also displayed a comparable performance with 20% Pt/C.

Metal-organic framework (MOF)-derived hollow cobalt sulfides have attracted extensive attention due to their porous shell that provides rich redox reactions for energy storage. However, their ultradispersed structure and the large size of MOF precursors result in relatively low conductivity, stability, and tap density. Therefore, the construction of an array of continuous hollow cages and tailoring of the inner cavity of MOF-derived materials is very effective for enhancing the electrochemical performance. Herein, we in situ assembled small Co-based zeolitic imidazolate framework (ZIF-67) on the both sides of negatively charged MnO 2 nanosheets to fabricate a hierarchical sandwich-type composite with hollow cobalt sulfide nanocages/graphene-like MnO 2 . The graphene-like MnO 2 nanosheets acted not only as a structure-directing agent to grow a ZIF-67 array but also as a promising electroactive material of electrochemical capacitors to provide capacitance. As an electrode material of supercapacitors, the as-prepared composites exhibit high specific capacitance (1635 F g -1 at 1 A g -1 ), great rate performance (reaching 1160 F g -1 at 10 A g -1 ), and excellent cycling stability (80% retention after 5000 cycles). The outstanding electrochemical properties of our designed materials can be attributed to the unique nanostructure that improved electrical conductivity, created more reactive active sites, and increased the diffusion pathway for electrolyte ions.