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Efficient nonprecious bifunctional electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential for improving the electrochemical performance of Zinc-air (Zn-air) batteries. Herein, we report a cobalt-doped Mn

Lithium–air batteries possess ultrahigh energy density compared to lithium-ion batteries because oxygen is applied as the reacting matter of the cathode without restrictions. However, they cannot b...

Rechargeable Zn–air batteries (ZABs), with a high theoretical energy density of 1084 W h kg−1, are considered as one of the most promising energy technologies for the emerging flexible and wearable electronics. However, the most challenging issue for ZABs is the sluggish kinetics and unsatisfactory stability for the oxygen reduction reaction/oxygen evolution reaction (ORR/OER) on the air electrode. Herein, a flexible, large-area 3D N-doped graphene-like full carbon air electrode with an O-rich functional group (NO-G@CP) was successfully synthesized using a cotton pad as a template via a scalable, low-cost and one-step pyrolysis process. Benefitting from the 3D porous N-doped graphene structure and rich CO group, the as-prepared NO-G@CP air electrode exhibits superior ORR/OER bifunctional catalytic activity and stability. Impressively, the integrated NO-G@CP can be directly used as an efficient air cathode for flexible solid-state ZABs. An open-circuit voltage of up to 1.328 V and a maximum power density of 65.1 mW cm−2 for the flexible solid-state ZABs have been obtained. This work provides valuable guidance toward the development of emerging flexible and wearable devices in practice.

Enhancing the discharge–charge durability of lithium–oxygen batteries (LOBs) is an urgent task for accelerating their commercial process. Here, we report our findings on the exploration of glow discharge plasma (GDP) in improving the durability of the Mo2C quantum dots decorated N-doped carbon nanofiber (Mo2C@NCF) electrocatalyst. When employed in LOBs, the Mo2C@ NCF electrode treated with GDP (GDP-Mo2C@NCF) delivers a significantly enhanced discharge–charge stability, sustaining over 100 cycles at a current density of 100 mA g−1 with a cut-off capacity of 1000 mA h g−1. The GDP treatment breaks the native MoOx passivation layer on the surface of Mo2C quantum dots and promotes the formation of an interfacial Mo–N bond between Mo2C and the N doped in carbon fibers, leading to the enhanced cycling durability. The work opens a promising avenue for improving the performance of LOBs through a facile surface modification.

The aprotic Li-O2 batteries with high theoretical energy density hold great promise for long-range electric vehicles and grid energy storage system. However, the high over-potential, poor cycling stability and the side reactions associated with the carbon electrocatalysts at the cathode limit the practical application of Li-O2 batteries. To address these challenges, in this work, oxygen defect-ridden molybdenum oxide (MoOx) was coated on the surface of carbon nanotubes (CNTs) (denoted as MoOx/CNT) by a facile solvothermal reaction for the first time. This MoOx layer not only protects the CNTs catalysts from the side reactions but also promotes the reversible formation of Li2O2, resulting in low overpotential and excellent cycling stability of MoOx/CNT cathode. A charging overpotential of only about 0.52 V and an enhanced stability of more than 210 cycles are obtained for the as-prepared MoOx-coated CNT cathode. First-principles study by density functional theory (DFT) reveals that the stabilization of LiO2 intermediates is enabled on oxygen-defected MoOx during discharge process, leading to the formation of large sheet-like Li2O2 crystallites that are easy to be decomposed during charge process. This makes a crucial contribution to the enhanced electrochemical performance of MoOx/CNT cathode.

Efficient catalyst for the oxygen reduction reaction (ORR) is of significance in the development of fuel cell and metal-air battery technologies. Heteroatom doped carbon materials have been considered as one of most promising alternatives to Pt-based catalysts. In this work, we exploit a nitrogen and sulfur dual-doped one-dimensional carbon rod catalyst with porous graphene-like layers on the surface derived from a Ni based metal-organic framework (MOF). The Ni-NSPC-6 catalyst with uniform distribution of N and S atoms in the carbon skeleton possesses a porous structure and a considerable specific surface area. Benefited from the special one-dimensional morphology, the convenient channel provided by the porous structure, the synergistic effect from the homogeneous co-doping of N and S, and the existence of proper amount of Ni3S2, the Ni-NSPC-6 affords a remarkable electrocatalytic performance toward ORR, including positive onset and half-wave potentials, a high catalytic current density, a low Tafel slope for oxygen reduction reaction and a remarkable ORR durability. The controllable synthesis of MOF derived S, N co-doped carbon materials with porous nanostructure will offer prospects in developing high performance electrocatalysts.

Compared to currently studied metal-based catalysts, metal-free heteroatom-doped carbon catalysts have many advantages including no issues of degradation and contamination from metal dissolution. Relying on single type of doping usually cannot yield optimal electronic and geometric structures favorable for the oxygen reduction reaction (ORR). Herein, heteroatom N, P, and S simultaneously doped graphene-like carbon (NPS-G) was successfully synthesized from onium salts by a facile one-step pyrolysis method. The resulting metal-free NPS-G catalyst with optimized N, P, and S contents exhibits enhanced catalytic activity towards the ORR in alkaline media, relative to any single doping. In particular, this metal-free catalyst shows an encouraging half-wave potential (E1/2 = 0.857 V) comparable to that of metal-based catalysts. It also demonstrates excellent electrochemical stability and methanol tolerance. This catalyst was further studied as a cathode in a primary Zn-air battery, showing exceptional open-circuit voltage (1.372 V) and power density (0.151 W cm−2). The NPS-G cathode delivers a specific capacity of 686 mA h gZn-1 at a current density of 10 mA cm−2 while utilizing 82.2% of the theoretical capacity (835 mA h gZn-1). The origin of high activity associated with various heteroatom dopings is elucidated through X-ray photoelectron spectroscopy analysis and density functional theory studies. The enhanced chemisorption of oxygen species (*OOH, *O and *OH) onto the dopants of the NPS-G catalysts reduces charge transfer resistance and facilitate the ORR. The porous 2D structure also contributes to the increase of active site density and facile mass transport.

In this geomorphological research, terrestrial laser scanning (TLS) and a global navigation satellite system (GNSS) were employed to monitor the evolution of surface deformation in two frost mounds located in the Qinghai-Tibet engineering corridor (QTEC). The QTEC is classified as a critical engineering and transportation corridor and is connected to both inland China and the Tibetan Plateau. The engineering infrastructures over the QTEC are distributed around two slopes. A high-accuracy FARO Focus3D X130 3D laser scanner, nine Trimble 5700 GNSS systems and a DJI Inspire 1 unmanned aerial vehicle (UAV) system were used to generate a 3D surface model for the slopes. The deployment of the GNSS datum points (GDPs), GNSS control points (GCPs), a reference sphere set and a set of rectangular white–black cardboards used as registration reference targets (RRTs) enhanced the capacity for data collection, registration and pre-processing of the TLS point cloud. The mapping changes of the slopes based on the TLS data were used to examine the 3D surface topography dynamics during different time periods. Soil temperature and moisture sensors were also adopted to monitor the water and heat exchange for one of the slopes, which can reveal the effects of the hydrothermal process on slope deformation during freeze-thaw cycles. This occurred mainly because the phase transitions initiated slope deformation due to water and heat transfer. The two slopes exhibited mainly thaw slumping during thawing periods and frost heaving during the freezing period, but the frost heaving was dominant after several freeze-thaw cycles. The implementation of TLS and hydrothermal measurement technologies allow for a better understanding and assessment of hazards related to slopes adjacent to engineering and transportation corridors, and this will provide guidance for the future of highway and high-speed railway design and construction along the QTEC.

Porous hexagonal FeCo2O4/CeO2 heterostructure with abundant interfaces has been synthesized by annealing of metal organic frameworks prepared by a facile self-precipitation method. The interface between FeCo2O4 and CeO2 is the main factor for the enhancement of catalytic activity and durability of FeCo2O4/CeO2 heterostructure. Keywords: Oxygen reduction reaction, Oxygen evolution reaction, Electrocatalyst, FeCo2O4/CeO2 heterostructure, Interface

Carbon is usually used as cathode material for Li-O2 batteries. However, the discharge product, such as Li2 O2 and LiO2 , could react with carbon to form an insulating lithium carbonate layer, resulting in cathode passivation and capacity fading. To solve this problem, the development of non-carbon cathodes is highly desirable. Herein, we successfully synthesized MnCo2 O4 (MCO) nanoparticles anchored on porous MoO2 nanosheets that are grown on Ni foam (current collector) (MCO/MoO2 @Ni), acting as a carbon- and binder-free cathode for Li-O2 batteries, in an attempt to improve the electrical conductivity, electrocatalytic activity, and durability. This MCO/MoO2 @Ni electrode delivers excellent cyclability (more than 400 cycles) and rate performance (voltage gap of 0.75 V at 5000 mA g-1 ). Notably, the battery with this electrode exhibits a high energy efficiency (higher than 85 %). The advanced electrochemical performance of MCO/MoO2 @Ni can be attributed to its high electrical conductivity, excellent stability, and outstanding electrocatalytic activity. This work offers a new strategy to fabricate high-performance Li-O2 batteries with non-carbon cathode materials.

Rechargeable lithium–oxygen (Li–O2) batteries have great potential for electric vehicles and grid energy storage system. The cathode catalysts play a crucial role in accelerating the oxygen reaction kinetics for improving battery performance. Herein, we employ hetero-atom doping method by combining hydrothermal reaction and ammonia-atmosphere calcination to introduce defects in MoS2 catalyst. The experimental results reveal the fabricated N-doped MoS2 (denoted as N-MoS2) catalysts introduced with abundant lattice defects while maintains the crystal structure of MoS2. The lithium–oxygen batteries with N-MoS2 catalyst as cathode show high initial specific capacity of 5500 mAh g–1 at 100 mA g–1 with good reversibility and efficiency. And the N-MoS2 cathode exhibits good rate capability and cycle stability up to 100 cycles. We reveal that the porous structure and lattice defects promote the exposition of active sites, resulting in higher electrochemical activity for oxygen reduction and the decomposition of discharge products. This work provides a promising avenue for constructing a bi-functional defected molybdenum disulfide catalyst by nitrogen doping in Li–O2 batteries.

Three-dimensional self-supported metallic structures are attractive for their unique properties of high porosity, good flexibility, large surface area per unit volume, and open-pore structure, which promote their broad application in fuel cells. Here, for the first time, a self-supported PtAuCu alloy and Pt supported over Cu2O, as two effective independent strategies, are combined into a single system, which leads to an enhanced electrochemical performance for the oxygen reduction reaction as compared to the commercial Pt/C. After cyclic voltammetry for 2000 cycles between 0.03 and 1.40 V, PtAuCu@Cu2O/Pt maintains high activity, whereas Pt/C shows a half-wave potential loss of around 20 mV. This work provides an effective strategy for rational design of highly active and stable catalysts for fuel cell applications and beyond.

Background: miR-124-3p has been reported to be involved in the pathogenesis of many diseases by modulating a variety of signaling pathways. In this study, we aimed to understand the impact of miR-124-3p expression level on the fracture healing in the patients of metaphyseal fracture of distal tibia, who received minimal invasive percutaneous plate osteosynthesis. Methods: We firstly collected 195 patients of metaphyseal fracture of distal tibia, and the genotype of rs531564 was determined: GG (n=124) and GC+CC (n=71). We collected information of the participants including age, gender, total in-hospital time, smoking and alcohol consumption. Subsequently, we searched the miRNA database online to identify the possible binding sequence of miR-124-3p located within the 3’-UTR of the target gene. We did correlation analysis and luciferase to understand the regulatory relationship between miR-124-3p and BMP6. Meanwhile, we also conducted real time PCR and western blotting analysis to study the mRNA and protein expression level of BMP6 in different genotype groups. We then treated the cells with scramble control, miR-124-3p mimics, BMP6 siRNA and miR-124-3p inhibitors to investigate the influence of miR-124-3p on the expression of BMP6, viability and apoptosis of cells. Results: Total in-hospital time was significantly longer in GC+CC group than GG group. MiR-124-3p was up-regulated in GG group than GC and CC groups. BMP6 was virtual target of miR-124-3p. There existed negative regulatory relationship betweenmiR-124-3p and BMP6. The mRNA and protein expression level of BMP6 decreased in GG group. MiR-124-3p decreased the expression of BMP6. MiR-124-3p negatively interfered with the viability of cells and BMP6 positively interfered with the viability of cells. MiR-124-3p reduced apoptosis and BMP6 promoted apoptosis. Conclusion: These data proved the expression of miR-124-3p was associated with the healing of metaphyseal fracture of distal tibia, and could be recognized as a biomarker to predict the healing of metaphyseal fracture of distal tibia.

// Chao Wang 1 , Xuecheng Cao 1 and Yongxian Zhang 1 1 Department of Orthopedic Injury, General Hospital of Jinan Military Area, Tianqiao District, Jinan, Shangdong, China Correspondence to: Yongxian Zhang, email: yongxianzhanggk@sina.com Keywords: osteogenesis scaffold, ascorbic acid, β-glycerophosphate, dexamethasone, bone regeneration Received: December 28, 2016 Accepted: January 17, 2017 Published: February 28, 2017 ABSTRACT Ascorbic acid, β-glycerophosphate, and dexamethasone have been used in osteogenesis differentiation medium for in vitro cell culture, nothing is known for delivering these three bioactive compounds in vivo . In this study, we synthesized a novel bioactive scaffold by combining these three compounds with a lysine diisocyanate-based polyurethane. These bioactive compounds were released from the scaffold during the degradation process. The cell culture showed that the sponge-like structure in the scaffold was critical in providing a large surface area to support cell growth and all degradation products of the polymer were non-toxic. This bioactive scaffold enhanced the bone regeneration as evidenced by increasing the expression of three bone-related genes including collagen type I, Runx-2 and osteocalcin in rabbit bone marrow stem cells (BMSCs) in vitro and in vivo . The osteogenesis differentiation of BMSCs cultured in this bioactive scaffold was similar to that in osteogenesis differentiation medium and more extensive in this bioactive scaffold compared to the scaffold without these three bioactive compounds. These results indicated that the scaffold containing three bioactive compounds was a good osteogenesis differentiation promoter to enhance the osteogenesis differentiation and new bone formation in vivo .

Nitrogen-doped carbon hollow cubes (NCHCs) are fabricated from biomass L-lysine monohydrochloride via a facile and low-cost NaCl template process, showing efficient bifunctional electrocatalytic activities towards the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The resultant lysine-derived carbon hollow cubes with hierarchical pores on the wall are conducive to mass transport and high utilization of nitrogen dopant-induced active sites during the electrocatalytic process. When used as electrocatalysts for the ORR, an onset potential of 0.92 V vs. RHE has been achieved for NCHCs. A negative shift of only 61 mV exists in the half-wave potential of NCHCs compared to that of the commercial Pt/C (20 wt%). Moreover, the NCHCs show high activity for the OER comparable to that of commercial RuO2/C (20 wt%). The sustainable conversion of biomass lysine to heteroatom-doped carbon hollow cubes and the recyclability of the NaCl template allow a scalable production and practical application of carbon materials for energy storage and conversion.

Advanced cathode catalysts are crucial to the promotion of aprotic Li–O2 batteries for practical applications. Carbon is usually used as a cathode catalyst, but it reacts with the discharge products (Li2O2, LiO2) to form an insulating layer of lithium carbonate and prevents further reaction. To resolve this issue, the development of non-carbon cathode catalysts is of great demand. Herein, for the first time, we designed and fabricated a MnCo2O4 (MCO) spinel oxide decorated Magneli phase Ti4O7 as a carbon-free cathode for Li–O2 batteries. The sub-stoichiometric Ti4O7 oxide serves as an electronic conductive network. The MCO spinel oxide along with the synergistic effect between Ti4O7 and MCO facilitate the kinetics of both oxygen reduction and decomposition of Li2O2. Furthermore, uniform anchoring of MCO nanoparticles on Ti4O7 surface provides a stable lithium peroxide–cathode interface during the discharge/charge process. The resulting Ti4O7/MCO hybrid proves to be a highly effective cathode catalyst. The discharge/charge voltage gap of the Ti4O7/MCO hybrid is about 0.75 V, which is significantly lower than that of pure carbon, C + MCO and pristine Ti4O7 cathode. A high specific capacity (5400 mA h g−1 at 100 mA g−1) and excellent cycling performance (100 cycles at a capacity of 500 mA h g−1 under 200 mA g−1) were obtained for this hybrid. The high catalytic activity and durability renders the Ti4O7/MCO hybrid a highly promising carbon-free cathode for Li–O2 batteries.

Efficient electrocatalyst for oxygen reduction reaction (ORR) is crucial for the performance improvement of fuel cells and metal-air batteries. However, catalyst with high activity, easy fabrication process, and low cost is still a daunting challenge. In this work, low-cost BaCO3 nanorods have been demonstrated as efficient electrocatalysts toward the ORR in alkaline media for the first time. The activity of BaCO3 nanorods can be further enhanced by hybridizing with reduced graphene oxide (BaCO3/rGO). The mechanism of ORR on the surface of BaCO3 catalyst was investigated via in situ electrochemical Raman spectroscopy (in situ EC-Raman). Our findings suggest that the barium ions on the surface of catalyst play a key role in the adsorption of oxygen molecules and the formation/decomposition of intermediates. This work provides an important insight into the catalytic activity of BaCO3 for ORR, which can serve as a guide for the design of alkali-earth metal-carbonate-based catalyst.

Developing cost-effective, sustainable and efficient electrocatalyst for the oxygen reduction reaction (ORR) is still a challenge for the practical application of fuel cells and metal-air batteries. The conversion of sustainable biomass into carbon provides a great opportunity to meet this challenge. In this work, without using any template, yolk-shell N/P/B ternary-doped biocarbon has been fabricated via a facile and low-cost biosynthesis method using yeast cells as precursor. The yolk-shell structure along with mesopores and micropores provides an efficient mass-transport pathway and increases the accessible active sites for the ORR. The doping of B increases the content of N doped in biocarbon, which favors the ORR. Significantly, the improved electrical conductivity and enhanced kinetics for charge transfer induced by co-doping of N, P and B with optimized content in carbon benefit the oxygen reduction kinetics. Thanks to these advantages, the as-prepared yolk-shell N/P/B ternary-doped biocarbon exhibits high electrocatalytic activity and good stability for ORR and high tolerance for methanol oxidation. A negative shift of about 56 mV in the onset potential and 79 mV in the half-wave potential of the biocarbon as compared to the commercial Pt/C (20 wt% Pt on Vulcan XC-72) for the ORR are achieved.

Osteoblasts are critical in bone remodeling and the repair of bone fractures. Leptin is involved in bone metabolism and osteoblast survival through the downstream signaling pathway, however, the exact mechanism of the effect of leptin on osteoblasts remains to be fully elucidated. In the present study, hFOB 1.19 cells were used to observe the effects of leptin on cell proliferation and apoptosis, and to investigate the underlying mechanism. The results confirmed that treatment of hFOB 1.19 cells with leptin significantly induced cell proliferation. Western blot analysis showed that the expression of caveolin-1 and the activation of Akt in the cells treated with leptin were significantly increased, compared with the control cells. Additionally, inhibiting Akt activation eliminated the effects on cell proliferation induced by leptin. The rates of cell apoptosis and cell cycle distribution were examined using flow cytometry, which revealed a decrease in the apoptotic rate and an increase in the proportion of cells in the S phase. This indicated that leptin was capable of inducing cell proliferation by inhibiting apoptosis and stimulating cell progression to the S phase. Transfection of the cells with caveolin-1 small interfering RNA showed that the activation of Akt induced by leptin was significantly inhibited. Furthermore, caveolin-1 knockdown and inhibiting Akt activation eliminated the increased proliferation, increased proportion of cells in the S phase and increased anti-apoptotic effects induced by leptin. Taken together, the data obtained in the present study demonstrated that caveolin-1 was critical in the proliferative effect of leptin on osteoblasts via the activation of Akt.

To expedite the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in electrochemical systems, efficient nonprecious electrocatalysts are highly desired. In this work, a hybrid of CoFe 2 O 4 nanoparticles supported on nitrogen/sulfur dual-doped three-dimensional (3D) reduced graphene oxide networks (CFO/NS-rGO) has been designed and fabricated. The doping of N and S provide the graphene networks with a large amount of defects. Moreover, both N and S doped in reduced graphene oxide play important roles in engineering the covalent coupling between CoFe 2 O 4 and the 3D graphene networks. The covalent coupling between CoFe 2 O 4 and NS-rGO along with the hierarchical porous structure and 3D networks endow the hybrid with a pronounced ORR activity (4-electron pathway), superior OER activity (comparable to that of the state-of-the-art RuO 2 /C catalyst) and high durability toward both ORR and OER.

The proinflammatory cytokines, especially tumor necrosis factor alpha (TNF-α), have been shown to inhibit osteogenic differentiation of mesenchymal stem cells (MSCs) and bone formation in estrogen-deficiency-induced osteoporosis, but the mechanisms of TNF-α impaired bone formation remain poorly understood. Semaphorins have been shown to regulate cell growth, cell migration, and cell differentiation in a variety of tissues, including bone tissue. Here, we identified a novel mechanism whereby TNF-α, suppressing Semaphorin3B expression contributes to estrogen-deficiency-induced osteoporosis. In this study, we found that TNF-α could decrease Semaphorin3B expression in osteogenic differentiation of MSCs. Overexpression of Semaphorin3B in MSCs attenuated the inhibitory effects of TNF-α on MSCs proliferation and osteoblastic differentiation. Mechanistically, activation of the Wnt/β-catenin signaling markedly rescued TNF-α-inhibited Semaphorin3B expression, suggesting that Wnt/β-catenin signaling was involved in the regulation of Semaphorin3B expression by TNF-α. Taken together, our results revealed a novel function for Semaphorin3B and suggested that suppressed Semaphorin3B may contribute to impaired bone formation by elevated TNF-α in estrogen-deficiency-induced osteoporosis. This study may indicate a therapeutic target gene of Semaphorin3B for osteoporosis.

Exploration of cost-effective electrocatalysts with high catalytic activity toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a key challenge in the development of metal-air batteries. In this study, bacterial-cellulose-derived carbon nanofiber-supported CoFe2O4 (CFO/CNF) has been prepared via a facile and green method. The three dimensional (3D) interconnected CNF network support with high surface area not only provides high electronic conductivity but also promotes the mass transfer of O2 and electrolyte during the ORR and OER. Furthermore, the strong coupling between CFO and CNF allows for fast charge transfer, facilitating the electrocataltyic processes. These lead to the high electrocatalytic activity of as-prepared CFO/CNF nanocomposite toward both the ORR and OER, outperforming CFO and CNF, respectively. Meanwhile, the stability of CFO/CNF nanocomposite toward the ORR and OER is much higher than that of benchmark Pt/C (20 wt.%) and RuO2/C (20 wt.%), respectively.

Efficient nonprecious electrocatalysts with fast kinetics for the the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are critical to improve the efficiency of electrochemical systems such as fuel cells and metal-air battereies. Here, Co 9 S 8 embedded in porous nitrogen-doped carbon (N-C) matrix has been designed and fabricated. The as-fabricated Co 9 S 8 /N-C hybrid shows an excellent ORR activity, which is comparable to that of the commercial Pt/C (20 wt.%). Notably, the OER activity of Co 9 S 8 /N-C hybrid is superior to that of the RuO 2 /C (20 wt.%), a benchmark electrocatalyst for OER. The stabilities of Co 9 S 8 /N-C hybrid toward ORR and OER are significantly improved as compared to that of Pt/C (20 wt.%) and RuO 2 /C (20 wt.%), respectively. The synergistic effect of the covalent coupling between Co 9 S 8 and N-C and the porous structure of N-C is responsible for the enhanced catalytic activity and durability of Co 9 S 8 /N-C hybrid.