Search

Background: Postpartum depression (PPD) is a prevalent psychiatric disorder during the postnatal period, and it exerts adverse impacts not only on mothers but also on infants, impairing the well‐being of the whole family. However, the role of peptides in the breast milk of mothers with PPD has not been studied. The purpose of this study was to unveil the peptidomic profile of PPD from breast milk samples. Methods: We performed comparative peptidomic profiling of human breast milk from PPD and control mothers using liquid chromatography–tandem mass spectrometry technology with iTRAQ‐8 labelling. GO and KEGG pathway analyses of precursor proteins were used to predict the underlying biological functions of differentially expressed peptides (DEPs). Ingenuity Pathway Analysis (IPA) was further performed to explore the interactions and involved pathways of DEPs. Results: A total of 294 peptides from 62 precursor proteins were identified to be differentially expressed in the breast milk of PPD mothers compared with the control group. Bioinformatics analysis predicted that these DEPs were associated with ECM–receptor interaction, neuroactive ligand‐receptor interaction, cell adhesion molecule binding and oxidative stress in macrophages. These results indicate that DEPs from human breast milk may play a part in PPD and become promising noninvasive biomarkers. Peptides from human breast milk were expected to be noninvasive biomarkers for postpartum depression. Bioinformatics analysis of differentially expressed peptides found that the pathogenesis of postpartum depression was closely related to ECM remodelling and macrophage‐mediated inflammation. [ABSTRACT FROM AUTHOR]

Objective: Pneumocystis jirovecii pneumonia (PJP) is a serious opportunistic infection mainly diagnosed in patients with rheumatic conditions. However, PJP in anti-melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5 + DM) patients remains poorly understood. We aimed to investigate the 6-month PJP risk in newly diagnosed MDA5 + DM patients. Methods: A retrospective observational study of 105 inpatients with newly diagnosed MDA5 + DM was conducted at Renji Hospital from January 2018 to November 2019. Demographic information, clinical characteristics, and treatment data were recorded. The primary outcome was PJP incidence within 6 months after a MDA5 + DM diagnosis. Results: The analysis included 105 patients, including 13 patients diagnosed with PJP during the observation period. The median time from the MDA5 + DM diagnosis to PJP was 89 ± 38 days. Compared with the PJP − patients, the PJP + patients had a significantly greater risk of mortality (69.2% vs. 13.0% P < 0.001). Regarding the baseline comorbidities, hypertension (P = 0.013) and cancer (P = 0.02) were more common in the PJP + group. Additionally, a larger proportion of the PJP + patients received prolonged high-dose steroid therapy (≥ 60 mg/day and ≥ 1 month) (P = 0.022) and double or triple immunosuppressant therapy (P = 0.013). The multivariate analysis showed that PJP was independently associated with lymphopenia (ALC < 500 cells/µl) (OR: 5.434, 95% CI: 2.074–55.155; P = 0.012) and the combined use of cyclophosphamide (CTX) and tacrolimus (TAC) (OR: 10.695, 95% CI: 1.440–20.508; P = 0.005). Conclusion: There was a high incidence and mortality in the MDA5 + DM patients with PJP, with patients on combined immunosuppressive treatments, particularly CTX and TAC, being at a higher risk. Prolonged high-dose steroid therapy (≥ 60 mg/day and ≥ 1 month) was another risk factor for PJP. Key Points • There was a high incidence and mortality in the MDA5 + DM patients with PJP. • Most PJP cases occurred within 3 months after the MDA5 + DM diagnosis. • The 6-month infection risk of PJP increased with the administration of multiagent immunosuppression, especially the combination of CTX and TAC. • Prolonged high-dose steroid therapy (≥ 60 mg/day and ≥ 1 month) was another risk factor for PJP. [ABSTRACT FROM AUTHOR]

Considering the lack of systematic reviews on e-government research, this study includes research categories, spatial structure, research paradigms and noteworthy future topics in the domain of e-government. We collect 142 keywords from 2646 papers published in the Web of Science from 2000 to 2019 as the study object. Then, we identify four research categories: (1) technology and modelling in e-government, (2) drivers of e-government development, (3) public management and (4) governmental management. From public and government perspectives, we outline the spatial structure which includes theories and practices research and conclude four research paradigms: (1) theoretical modelling and application, (2) e-government development, (3) status of public management and (4) status of governmental management. Finally, we develop a 3D spatial map to analyse noteworthy topics and explore the well-studied themes: government-to-citizen, government-to-government and government-to-business, and the under-studied themes: government-to-civil society organisations and citizens-to-citizens, which helps scholars research e-government roundly. [ABSTRACT FROM AUTHOR]

Summary: With the advent of the Internet of Things (IoT), the count of gadgets connected to the Internet has been increased. IoT, as a modern paradigm, has been used to describe the future in which physical things like RFID tags, sensors, actuators, and cellphones can intermingle for achieving shared purposes. Also, we can employ cloud computing for storing the things' information in the IoT. However, this information has been replicated through the network for increasing availability. In this paper, due to the NP‐hard nature of the replica selection problem, an improved version of ant colony optimization (IACO) has been applied. The impact of pheromone on the chosen path is converted by ants to invert the underlying logic of ACO. Due to the existence of different IoT centers, the IACO has been employed for selecting the replicated data in the IoT where the load balancing among IoT centers has been considered. In this method, an ant chooses the ideal point for its movement; then others may not pass the track that the preceding ants have been passed. The obtained outcomes have shown that the method has outperformed the ACO, HQFR, and RTRM approaches regarding the waiting time and load balancing. [ABSTRACT FROM AUTHOR]

Alumina-supported Pd-Zn bimetallic catalysts were prepared and evaluated for direct synthesis of hydrogen peroxide. The effect of Zn on the catalytic performance was studied via characterizations by transmission electron microscopy (TEM), temperature-programmed reduction (TPR), X-ray photoelectron energy spectroscopy (XPS), temperature-programmed desorption of H 2 /O 2 (H 2 -/O 2 -TPD), CO chemisorption and diffuse reflectance infrared Fourier transform spectroscopy of CO adsorption (CO-DRIFTS). H 2 O 2 productivity of up to 25431 mol kg Pd −1 h −1 was observed with the optimal bimetallic catalyst 1Pd5Zn, much higher than that over the monometallic catalyst 1Pd (8533 mol kg Pd −1 h −1 ). This increase may be attributed to the geometric change caused by the Zn additive and the electronic interactions between Pd and Zn. The addition of Zn increases the isolated Pd sites (the primary active sites for H 2 O 2 formation), which can promote H 2 O 2 selectivity. PdZn catalysts show a higher Pd dispersion and incremental Pd 0 content than monometallic Pd owing to electronic interactions between Pd and Zn, which result in increased H 2 O 2 productivity. However, a high Pd dispersion and incremental Pd 0 content can increase the H 2 O 2 hydrogenation rate, negatively affecting the H 2 O 2 selectivity. [ABSTRACT FROM AUTHOR]

Context:Silymarin is the main flavonoid extracted from milk thistle, which has been used to treat liver diseases. Objective:Thein vivoeffect of silymarin on HFD-induced insulin resistance and fatty liver in mice was studied. Materials and methods:Male C57BL/6 mice were fed with high-fat diet (HFD) to induce obesity and insulin resistance and treated with 30, 60 mg/kg silymarin for 18 days. Food intake, body weight and the content/histology of epididymal fat and liver tissue were examined; the content of lipids, AST, ALT and inflammatory cytokines in serum were estimated. Results:Administration of silymarin caused bodyweight loss in diet induced obesity (DIO) mice (HFD group: 47.7 g, 60 mg/kg group: 43.0 g) while the food intake remain unchanged. Silymarin (60 mg/kg) significantly reduced the epididymal fat mass (from 1.75 g to 1.12 g). Elevated plasma lipids (TC 6.1 mM, TG 1.3 mM, LDL 1.2 mM) in DIO mice were all suppressed by silymarin (TC 4.5 mM, TG 0.89 mM, LDL 0.9 mM), as well as insulin (5.1 ng/ml in HFD group to 2.0 ng/ml (60 mg/kg silymarin). Examination of cytokine levels (TNF-α, IL-1β and IL-6) in each group proved that silymarin treatment significantly decreased inflammation in DIO mice. Finally, silymarin effectively protected liver from HFD-induced injury as evidenced by decreasing histological damage and reducing ALT and AST levels, as follows: ALT; 47.4 U/L in HFD group to 28.4 U/L (60 mg/kg silymarin); AST; 150.1 U/L in HFD group to 88.1 U/L (60 mg/kg silymarin) in serum. Discussion and conclusion:Our results suggested that silymarin-induced alleviation of inflammatory response could be a mechanism responsible for its benefits against liver damage and insulin resistance. [ABSTRACT FROM AUTHOR]

Catalyst layers (CLs) with spatially ordered structure can improve mass transport of reactants/products, which is essential for the high performance of polymer electrolyte membrane fuel cells (PEMFCs). In this study, aligned polyaniline (PANI) nanorods grown on gas diffusion layers by in situ polymerization are used as supports for platinum to fabricate ordered CLs. The length and diameter of the PANI nanorods can be controlled by optimizing the reaction temperatures or the aniline concentrations during the in situ polymerization process. With the optimized aligned PANI nanorods as supports of cathode, the mass specific power density of the PEMFC reaches 2.5 kW g Pt −1 , which is 21% higher than that of the conventional PEMFC without PANI. This improvement can be attributed to the reduced oxygen transport resistance revealed by oxygen gain and electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

The alkaline stability of 1,2-dimethylimidazolium with various N3-substituents (including butyl, benzyl and vinylbenzyl) and corresponding quaternary ammonium small molecular compounds, and the 1,2-dimethylimidazolium- and quaternary ammonium-based membranes are systemically studied in the same condition. The spectroscopy (such as NMR, FT-IR, XPS and mass spectrum) results of the two kinds of small molecular compounds indicate that the quaternary ammonium cations are more stable than 1,2-dimethylimidazolium cations in 3 M KOH at elevated temperature, especially at 80 °C. Moreover, the alkaline stability of the 1,2-dimethylimidazolium cations would be influenced by the N3-substitutions of the imidazolium, and N3-butyl substituted cation shows a better alkaline stability. The quaternary ammonium-based membrane are also more stable than the 1,2-dimethylimidazolium-based membrane in 1 M KOH at 60 °C. In addition, the performance of the alkaline direct methanol fuel cell using quaternary ammonium-based membrane (22 mW cm −2 ) is much better than that of the fuel cell using 1,2-dimethylimidazolium-based membrane (0.04 mW cm −2 ). [ABSTRACT FROM AUTHOR]

The cross-linked and alkali stable alkaline anion exchange membranes (AAEMs) based on 1,2-dimethylimidazolium (proved to be much more stable than C2-unsubstituted imidazolium cation) were prepared by a hot-pressing method. The properties of these membranes, e.g., water uptake, swelling degree, ion-exchange capacity, conductivity and thermal and chemical stability, were characterized systematically. The swelling degree of the membranes decreases with the decrease of the amount of 1,2-dimethylimidazolium salt, up to 5.8%. The membranes are thermally stable below 200 °C. Alkaline direct methanol fuel cell (ADMFC) fabricated by using CoO x /C as the cathode catalyst and PtRu/C as the anode catalyst presents a promising performance with the peak power density of 12.7 mW cm −2 at a current density of 45 mA cm −2 , indicating that the 1,2-dimethylimidazolium-functionalized AAEMs are promising for the application in ADMFCs. [ABSTRACT FROM AUTHOR]

Microscopic polyangiitis (MPA) is a systemic small-vessel vasculitis associated with anti-neutrophil cytoplasmic antibody (ANCA) and predominantly causes kidney and pulmonary injuries. Subarachnoid hemorrhage, a life-threatening manifestation of the central nervous system (CNS), rarely occurs in patients with ANCA-associated vasculitis (AAV). We report the case of a young man with spontaneous SAH recurrence and active nephritis. The patient was treated with a glucocorticoid pulse and intravenous cyclophosphamide (CTX) in combination with decreasing cerebral perfusion pressure and analgesic therapy. All the patients' symptoms except the proteinuria resolved. We reviewed the clinical characteristics of 34 previously reported cases of SAH with AAV, comprising six cases of MPA, eight cases of granulomatosis with polyangiitis (GPA), and 19 cases of eosinophilic granulomatosis with polyangiitis (EGPA), and one case of unclassified AAV. All the cases showed features of active vasculitis. Concomitant nephritis and peripheral neuropathy were found in the MPA and EGPA cases with SAH, respectively. Renal and pulmonary manifestations were predominant in the patients with GPA and SAH. Ten patients had aneurysmal abnormalities, and six patients had cardiac abnormalities. Thirty-one patients were treated with glucocorticoids, and 18 patients received concurrent immunosuppressants. Patients with SAH had a mortality rate of 38.2%. The presence of cerebrovascular events or cardiac involvement in patients with AAV and SAH is associated with increased mortality of 64.3%. Our study indicates that SAH should be cautioned as a disease occurring in patients with AAV. Early diagnosis with aggressive immunosuppressive therapy can help improve the prognosis of patients with SAH. [ABSTRACT FROM AUTHOR]

We propose and study a stochastic delay single-species population system in polluted environment with psychological effect and pulse toxicant input. We establish sufficient conditions for the extinction, nonpersistence in the mean, weak persistence, and strong persistence of the single-species population and obtain the threshold value between extinction and weak persistence. Finally, we confirm the efficiency of the main results by numerical simulations. [ABSTRACT FROM AUTHOR]

Two C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups (─CF3), Ni{PhC(O)CHC[N(9‐fluorenyl)]CF2}2 (Ni1) and Ni{CF3C(O)CHC[N(9‐fluorenyl)]Ph}2 (Ni2), were synthesized by metal coordination reaction and different in situ bonding mechanisms. The C–C bridged bonds of Ni1 were formed by in situ intramolecular trifluoromethyl and 9‐fluorenyl carbon–carbon cross‐coupling reaction and those of Ni2 were formed by in situ intramolecular 9‐fluorenyl carbon–carbon radical coupling reaction mechanism. The obtained complexes were characterized using 1H NMR spectroscopy and elemental analyses. The crystal and molecular structures of Ni1 and Ni2 with C–C bridged configuration were determined using X‐ray diffraction. Ni1 and Ni2 were used as catalysts for norbornene (NB) polymerization after activation with B(C6F5)3 and the catalytic activities reached 106 gpolymer molNi−1 h−1. The copolymerization of NB and styrene catalyzed by the Ni1/B(C6F5)3 system showed high activity (105 gpolymer molNi−1 h−1) and the catalytic activities decreased with increasing feed content of styrene. All vinyl‐type copolymers exhibited high molecular weight (104 g mol−1), narrow molecular weight distribution (Mw/Mn = 1.71–2.80), high styrene insertion ratios (11.13–50.81%) and high thermal stability (Td > 380°C) and could be made into thin films with high transparency in the visible region (400–800 nm). Novel C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups were synthesized by metal coordination and different in situ intramolecular bonding mechanisms, and applied in the (co)polymerization of norbornene and styrene. The copolymers were obtained with high styrene monomer content, and exhibited high thermal stability, narrow molecular weight distribution and high transparency in the visible region. [ABSTRACT FROM AUTHOR]

High oxygen transport resistance in the cathode is a main cause of the low performance of high temperature proton exchange membrane fuel cell (HT-PEMFC), and therefore to determine the contribution of different mass transport processes to the oxygen transport resistance is beneficial to the subsequent research work. In this paper, the molecular diffusion resistance (R M) in the cathode was successfully calculated by measuring the limiting currents with using different diluent gases. And the oxygen transport resistance in phosphoric acid (R P A ) was analyzed by changing the humidity and temperature. It was found that the total oxygen transport resistance (R t o t a l ) increased obviously with the increase of the humidify, and the variation of R t o t a l under different conditions was mainly related to the change of R P A . Combined with the phenomenon that the experimental value of R M was less than the calculated value at high humidity, but higher than that at high operation temperature, we speculate that the cause of that R P A increased obviously at high humidity is the occupancy or blockage of gas phase transport channel in catalyst layer (CL) by phosphoric acid due to the water absorption of phosphoric acid in CL and the swelling of membrane. This consequence indicates that it is the change of phosphoric acid distribution that dominate C i s the R t o t a l at high humidity. Image 1 • The separation of molecular diffusion resistance from the total mass transport resistance of HT-PEMFC cathode was realized. • The relationship between the oxygen transport resistance in phosphoric acid and operating conditions was obtained. • The cause of the variation of oxygen transport resistance at different operating conditions was preliminarily analyzing. [ABSTRACT FROM AUTHOR]

The significant use of platinum for catalyzing the cathodic oxygen reduction reactions (ORRs) has hampered the widespread use of polymer electrolyte membrane fuel cells (PEMFCs). The construction of well-defined electrode architecture in nanoscale with enhanced utilization and catalytic performance of Pt might be a promising approach to address such barrier. Inspired by the highly efficient catalytic processes in enzymes with active centers embedded in charge transport pathways, here we demonstrate for the first time a design that allocates platinum nanoparticles (Pt NPs) at the boundaries with dual-functions of conducting both electrons by aid of polypyrrole and protons via Nafion® ionomer within hierarchical nanoarrays. By mimicking enzymes functionally, an impressive ORR activity and stability is achieved. Using this brand new electrode architecture as the cathode and the anode of a PEMFC, a high mass specific power density of 5.23 W mg−1Pt is achieved, with remarkable durability. These improvements are ascribed to not only the electron decoration and the anchoring effects from the Nafion® ionomer decorated PPy substrate to the supported Pt NPs, but also the fast charge and mass transport facilitated by the electron and proton pathways within the electrode architecture. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of structure evolution under working condition of MNC electrocatalysts on the OER activity and stability has been studied with the DFT method. • This work conducted a comprehensive evaluation method for MNC electrocatalysts by taking ΔG *OH as the screening criterion for OER activity and ΔE b of electrocatalysts under working conditions as the stability descriptor. • The stability of MNC electrocatalysts under working conditions, including high temperature, dynamic condition, local electric field and strong specific adsorption has been studied in detail. Developing low-cost, high activity and stability oxygen evolution reaction (OER) catalysts is significantly important but still challenging for water electrolyzers. In this work, we calculated the OER activity and stability of Metal-Nitrogen-Carbon (MNC, M = Co, Ru, Rh, Pd, Ir) based electrocatalyst with different structures (MN 4 C 8 , MN 4 C 10 , MN 4 C 12) using density functional theory (DFT) method. These electrocatalysts were divided into three groups based on the value of ΔG *OH , that is ΔG *OH > 1.53 eV (PdN 4 C 8 , PdN 4 C 10 , PdN 4 C 12), ΔG *OH < 1.23 eV (RuN 4 C 8 , RuN 4 C 10 , RuN 4 C 12 , CoN 4 C 8 , CoN 4 C 10) and 1.23 eV < ΔG *OH < 1.53 eV (RhN 4 C 8 , RhN 4 C 10 , RhN 4 C 12 , IrN 4 C 8 , IrN 4 C 10 , IrN 4 C 12 , CoN 4 C 12), and ΔG *OH determine whether the structure evolution will appear. The results proved that MNC (M = Rh, Ir) with 1.23 eV < ΔG *OH < 1.53 eV shows higher OER activity due to moderate binding energy between reaction intermediates and MNC. Furthermore, these catalysts could maintain M N C structure without further oxidation and structural evolution under working conditions (high temperature, dynamic condition, local electric field and strong specific adsorption), therefore show excellent stability. However, MNC electrocatalyst with ΔG *OH > 1.53 eV or ΔG *OH < 1.23 eV revealed less stability under working conditions, due to their low intrinsic stability or structural evolution under working conditions, respectively. In conclusion, we proposed a comprehensive evaluation method for MNC electrocatalysts by taking ΔG *OH as the screening criterion for OER activity and stability, as well as ΔE b under working condition as descriptor of stability. This is of great significance for the design and screening of ORR, OER and HER electrocatalysts under working conditions. [ABSTRACT FROM AUTHOR]

A high performance polymer electrolyte thermogalvanic cell, which converts thermal energy to electrical energy directly, is transformed from a proton exchange membrane fuel cell. The transform is realized by connecting the anode and cathode chamber with a gas tube and filling hydrogen to both chambers. Provided a heat flux through the cell, hydrogen is consumed in the cold side and regenerated in the hot side while circulating in two chambers during operation. The Seebeck coefficient is 0.531 mV K −1 at a cold side temperature of 60.0 °C and the maximum power density could reach up to 20 μW cm −2 with a temperature difference of 15.3 °C between two electrodes. [ABSTRACT FROM AUTHOR]

Glucocorticoids (GCs) are the most effective and commonly used drugs for the treatment of systemic lupus erythematosus (SLE). However, a large number of side effects occur after long-term or high-dose glucocorticoid treatment, which severely restricts the use of glucocorticoids. Reconstituted high-density lipoprotein (rHDL), an emerging nanocarrier, is promising for targeted delivery to sites of inflammation and macrophages. Here, we prepared a steroid-loaded recombinant high-density lipoprotein and evaluated its therapeutic efficacy in a murine macrophage cell line (RAW264.7) and a lupus (MRL/lpr mice) mouse model. The obtained corticosteroid-loaded nanomedicine, named PLP-CaP-rHDL, exhibited desirable characteristics. Pharmacodynamics studies revealed that the nanoparticles could significantly reduce the levels of inflammatory cytokines in the macrophages in vitro and also effectively alleviate lupus nephritis in MRL/lpr mice without causing obvious side effects at a dose of 0.25 mg/kg. Thus, our newly developed steroid-loaded rHDL nanocarriers hold a great potential for anti-inflammatory therapy with reduced side effects and may provide a precise targeted therapy for SLE. [ABSTRACT FROM AUTHOR]

We designed this study to investigate the effects of the coronavirus disease 2019 (COVID-19) vaccine on epileptic seizures, as well as its adverse effects, in children with epilepsy (<18 years). This anonymous questionnaire study involved a multicenter prospective survey of outpatients and inpatients with epilepsy (＜18 years) registered in epilepsy clinics in eight hospitals in six cities of Shandong Province. A total of 224 children with epilepsy were included in the study. Fifty of them experienced general adverse events after vaccination. The most common local adverse events were pain or tenderness at the injection site. The most common systemic adverse effects were muscle soreness and headache. No severe adverse events were reported. There were no significant differences in the number of antiseizure medications (P = 0.459), gender (P = 0.336), etiology (P = 0.449), age (P = 0.499), duration of disease (P = 0.546), or seizure type (P = 0.475) between the patients with and without general adverse events. We found that the risk of seizure after vaccination was decreased in children who were seizure free for more than six months before vaccination. There was no significant difference in the number of seizures during the first month before vaccination, the first month after the first dose, and the first month after the second dose (P = 0.091). The benefits of vaccination against COVID-19 outweighed the risks of seizures/relapses and severe adverse events after vaccination for children with epilepsy. [ABSTRACT FROM AUTHOR]

Researching of high performance and low-cost oxygen reduction reaction (ORR) electrocatalysts is one of the core issues for the rapid development of energy conversion and storage devices. Herein, a N and S dual-doped three-dimensional (3D) interconnected mesoporous carbon catalyst (CNS) was constructed via a facile hydrothermal-pyrolysis strategy. Benefiting from the 3D interconnected mesoporous architecture, CNS was endowed with a fast oxygen mass transfer rate together with plentiful of accessible active centers on the surface. Its ORR half-wave potential (E 1/2 ， 0.87 V) surpasses commercial Pt/C catalyst 50 mV in alkaline media. Its E 1/2 negatively shifts only 2 mV after 8000 cycles in half-cell tests. More importantly, the zinc-air battery with CNS as cathode catalyst delivers an excellent high peak power density of 144 mW cm−2. DFT calculation results show that when N and S are co-doped, the spin density of adjacent carbon atoms can be changed, thereby increasing the CNS's binding energy to oxygen and conductivity. The excellent comprehensive performance of CNS undoubtedly discloses its potential practical application in the energy conversation and storage area. [Display omitted] [ABSTRACT FROM AUTHOR]

In this article, a nonthermal gliding arc discharge (GAD) was generated in an air flow driven by a 40-kHz alternating current (ac) constant-current electric power supply. The influence of gas flow rate on the discharge characteristics of gliding arc was investigated using electrical diagnostics and fast Fourier transform (FFT) analysis method. The average discharge power, total harmonic distortion rate of arc voltage (THD ${_{u}}$), total harmonic distortion rate of arc current (THD ${_{i}}$), and the resistance of arc were experimentally studied. As the air flow rate increased from 4 to 12 L/min, it was found that the average discharge power of the gliding arc gradually decreased from 407.9 to 187.8 W. However, because of the nonlinear characteristics of the GAD circuit, with air flow rate increasing, both THDu and THDi linearly increased, while the resistance of arc gradually decreased from 26.3 to 14.1 $\text{k}\Omega $. Totally, the air flow rate influenced the discharge characteristics of the gliding arc mainly by ruling the average discharge power. Finally, for a better understanding of the discharge characteristics of the gliding arc, a discharge circuit model was further analyzed based on the average discharge power and reactive power. [ABSTRACT FROM AUTHOR]

Charge transport processes involving the proton migration and electron transfer for different parts of membrane electrode assemble (MEA) play an essential role for developing the novel electrode and enhancing the electrochemical performance towards proton exchange membrane fuel cells (PEMFCs). However, the coupled charge transport processes make it difficult for evaluating proton conductivity and electronic conductivity of different parts in MEAs under operation conditions of fuel cells. Here in this work, we propose an experiment approach for separating the electronic conductivity and proton conductivity of different components of MEA at the operating conditions of PEMFCs. This approach involves two different measuring devices, which both consist of electron or proton conducting layers, sealing layers and sample layer, followed by tailoring the thickness of sample layers and via electrochemical impedance spectroscopy (EIS) to quantity the electronic conductivity and proton conductivity of different layers. These experiment results show the great potential in the development of different components of MEA. Image 1 • Electronic conducitivity of different parts of MEA are explored. • Proton conductivity of CL and PEM were evaluated. • Interfaces, CL and PEM play a vital role in internal resistance of MEA. [ABSTRACT FROM AUTHOR]

Background: Undifferentiated connective tissue disease (UCTD) is known to induce adverse pregnancy outcomes and even recurrent spontaneous abortion (RSA) by placental vascular damage and inflammation activation. Anticoagulation can prevent pregnancy morbidities. However, it is unknown whether the addition of immune suppressants to anticoagulation can prevent spontaneous pregnancy loss in UCTD patients. The purpose of this study is to evaluate the efficacy of hydroxychloroquine (HCQ) and low-dose prednisone on recurrent pregnancy loss for women with UCTD.Methods: The Immunosuppressant for Living Fetuses (ILIFE) Trial is a three-arm, multicenter, open-label randomized controlled trial with the primary objective of comparing hydroxychloroquine combined with low-dose prednisone and anticoagulation with anticoagulation alone in treating UCTD women with recurrent spontaneous abortion. The third arm of using hydroxychloroquine combined with anticoagulant for secondary comparison. A total of 426 eligible patients will be randomly assigned to each of the three arms with a 1:1:1 allocation ratio. The primary outcome is the rate of live births. Secondary outcomes include adverse pregnancy outcomes and progression of UCTD.Discussion: This is the first multi-center, open-label, randomized controlled trial which evaluates the efficacy of immunosuppressant regimens on pregnancy outcomes and UCTD progression. It will provide evidence on whether the immunosuppressant ameliorates the pregnancy prognosis in UCTD patients with RSA and the progression into defined connective tissue disease.Trial Registration: ClinicalTrials.gov NCT03671174 . Registered on 14 September 2018. [ABSTRACT FROM AUTHOR]

The strain effect on oxygen reduction reaction (ORR) activity and stability of FeNC electrocatalysts has been studied using density functional theory in this work. Based on the reaction free energy results, the rate-determining step (RDS) of ORR on FeNC is *OH → H2O, and the reaction proceeds with the pathway O2 → *OOH → *O → *OH → H2O on the Fe site. Tensile stress is favorable to enhance the ORR activity, and the highest ORR activity is obtained on the 6%-FeNC electrocatalyst. On the other hand, when the whole oxygen reduction process needs synergy between Fe and adjacent C atoms and proceeds with the pathway O2 → *OOH → *TS → *O & #OH → *O → *OH → H2O, the applied stress will decrease the ORR activity of the FeNC electrocatalyst. We further constructed a Cu@FeNC core–shell model to simulate strained FeNC. However, the adsorption energy of ORR intermediates on Cu@FeNC (1.9%-FeNC) is much weaker than on the corresponding 2%-FeNC, mainly due to the coordination between the Cu substrate and Fe atom. In addition, the formation energy and binding energy indicate that neither tensile nor compressive stress is conducive to the stability of the FeNC electrocatalyst. In summary, tensile stress could enhance the ORR activity of FeNC electrocatalysts when ORR occurs on the Fe atom only. What's more, we should pay more attention to the influence of interface interaction if utilizing a M@FeNC model to achieve strained FeNC. [ABSTRACT FROM AUTHOR]

Despite the improvement in acute myeloid leukemia (AML) treatments, most patients had a poor prognosis and suffered from chemoresistance and disease relapse. Therefore, there is an urgent need for elucidation of mechanism(s) underlying drug resistance in AML. In the present study, we found that AML cells showed less susceptibility to adriamycin (ADR) in the presence of hypoxia, while inhibition of hypoxia‐inducible factor 1α (HIF‐1α) by CdCl2 can make AML cells re‐susceptibile to ADR even under hypoxia. Moreover, HIF‐1α is overexpressed and plays an important role in ADR‐resistance maintenance in resistant AML cells. We further found hypoxia or induction of HIF‐1α can significantly upregulate yes‐associated protein (YAP) expression in AML cells, and resistant cells express a high level of YAP. Finally, we found that YAP may not only enhance HIF‐1α stability but also promote HIF‐1α's activity on the target gene pyruvate kinase M2. In conclusion, our data indicate that HIF‐1α or YAP may represent a therapeutic target for overcoming resistance toward adriamycin‐based chemotherapy in AML. [ABSTRACT FROM AUTHOR]

Background: Menopause syndrome generally includes psychological problems. Group treatment delivered via the Internet and mobile phone (imGT) may improve women's physiological and psychological conditions.Objective: To investigate the efficacy of group cognitive behavioural therapy of menopause-related mood swings and quality of life, delivered face to face or via the Internet and mobile phone.Methods: This protocol is for a randomized controlled clinical trial with a sample of 140 menopausal women divided into 2 groups: imGT and face-to-face group treatment (ffGT). The primary outcome will be the improvement in the menopausal symptoms of the two groups, as assessed by the Greene Climacteric Scale. The secondary outcomes will be: quality of life, assessed by the Short Form 36 Health Survey Questionnaire; insomnia, assessed by the Pittsburgh Sleep Quality Inventory; anxiety, assessed by the Hamilton Anxiety Rating Scale; and therapeutic alliance, assessed by the Working Alliance Inventory-Short Revised and Client Sat-is-fac-tion Qes-tion-naire-8. imGT will be performed once a week for 1.5 h for 10 weeks with a daily 'Punched-in' on the WeChat app; ffGT will be performed once a week for 1.5 h for 10 weeks. All outcomes will be assessed at baseline, at a post-intervention evaluation (week 10), and at a follow-up evaluation (week 22).Discussion: This study will be the first clinical trial to examine the effects of imGT on menopausal women in China. If imGT is found to be non-inferior to ffGT, it will facilitate access to menopausal health services. [ABSTRACT FROM AUTHOR]

Ovarian cancer remains the most fatal gynecologic malignancy worldwide due to delayed diagnosis as well as recurrence and drug resistance. Thus, the development of new tumor-related molecules with high sensitivity and specificity to replace or supplement existing tools is urgently needed. Cancer-testis antigens (CTAs) are exclusively expressed in normal testis tissues but abundantly found in several types of cancers, including ovarian cancer. Numerous novel CTAs have been identified by high-throughput sequencing techniques, and some aberrantly expressed CTAs are associated with ovarian cancer initiation, clinical outcomes and chemotherapy resistance. More importantly, CTAs are immunogenic and may be novel targets for antigen-specific immunotherapy in ovarian cancer. In this review, we attempt to characterize the expression of candidate CTAs in ovarian cancer and their clinical significance as biomarkers, activation mechanisms, function in malignant phenotypes and applications in immunotherapy. [ABSTRACT FROM AUTHOR]

• Ultrathin 2D metal-organic frameworks decorated with Pt NPs have been fabricated using an ultrasonication-assisted method. • A "win-win" electron decoration effect has been evidenced on the active sites for both ORR and OER. • Remarkable bifunctional catalytic activity towards ORR and OER with ultralow overpotential gap of 665 mV has been demonstrated. • Excellent performance and durability is achieved in the rechargeable Zinc-air battery assembled with the bifunctional catalyst. To meet the increasing demands for highly active electrocatalysts towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), here in this work, a new strategy of synergistic nano-architecture design based on Platinum nanoparticles (Pt NPs) and ultrathin two-dimensional (2D) metal-organic frameworks (MOFs) is developed for bifunctional electrochemical catalysts. Compared with commercial Pt/C and RuO 2 catalysts, remarkable enhancements in activity and durability of both oxygen reduction and oxygen evolution reactions are achieved on our PtNPs@MOFs composite materials, with one of the lowest over-potential gaps (E gap) of 665 mV that has ever been reported. The tests on the assembled Zn-air batteries have revealed promising electrocatalytic performance and practical advantage of our new materials as air cathode catalyst. Both experimental results and theoretical study have confirmed the synergistic effect between Pt NPs and MOF nanosheets through a "win-win" electron structural modification, demonstrating the effectiveness of our strategy in developing effective bifunctional oxygen electrocatalysts for various types of electrochemical devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design of the prior PA-resistance electrocatalysts through theoretical calculation. • Discovery of different scaling relationship of the adsorption energy difference of O 2 and H x PO(3-x)- 4 on Pt 3 M(1 1 1) alloy surface. • Pt X Cu as the object for the research of internal mechanism of the potentially high PA resistance property. • Higher PA-resistance performance of Pt 2 Cu compared to the commercial PtC in half-cell and full-cell tests. In high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs), dissociative H 3 PO 4 in cathode will block the active sites of Pt-based electrocatalyst, which thus failure to catalyze the oxygen reduction reaction (ORR). Therefore, the electrocatalysts for the ORR in HT-PEMFCs with high resistance to H 3 PO 4 poisoning are significantly important. Due to the similar bonding structure between H x PO 4 3-x/O 2 and Pt (Pt-O), the design of catalysts which could selectively reduce the adsorption energy of the H 3 PO 4 is urgently needed. In this work, we screen proper H 3 PO 4 resistance electrocatalysts through theoretical calculation based on the adsorption energy difference between H x PO 4 3-x and O 2 as an evaluation criterion. Then, we prepared a series of Pt x Cu catalysts based on the theoretical calculation results and further studied the structure-performance relationship of phosphoric acid-resistant catalysts through combining physical property characterization and electrochemical tests including half-cell and single-cell. The mass activity of Pt 2 Cu/C is 0.51 A/mg Pt , exceeding the DOE's 2020 target of 0.44 A/mg Pt. After add 0.1 M H 3 PO 4 into the HClO 4 electrolyte, the half-wave potential (E 1/2) of Pt 2 Cu/C is only negatively shifted by 47 mV, much lower than 90 mV of TKK Pt/C. Furthermore, the HT-PEMFC with Pt 2 Cu/C in the cathode shows a peak power density of 383.4 mW/cm2, which surpasses that of TKK Pt/C for 231.0 mW/cm2. Our strategy of screening catalysts based on the adsorption energy difference study and further verified by experimental methods provides a promising strategy for the design of practical electrocatalyst in the cathode of HT-PEMFCs. [ABSTRACT FROM AUTHOR]

Construction of advanced electrode architecture, and understanding the electrochemical and mass transport phenomena within its structures are core issues that determine the development of fuel cells and other electrochemical energy technologies. Here in this work, we propose a new scaffold-like electrode with controllable porous volume and size via facile freeze-drying process. Deriving from the delicate surface unevenness and the well-defined macro-pores constructed by the ice template, the electrochemical surfaces and mass transport for methanol and oxygen are greatly enhanced by adapting this electrode structure as anode and cathode for direct methanol fuel cells, respectively. Computational fluid dynamics simulation and mathematic model is adopted to elucidate and predict the intrinsic improvement of mass transport within the newly designed electrode structure. Further practical application of such design is validated in a 10-cell short stack of direct methanol fuel cell systems equipped with this novel electrode. [ABSTRACT FROM AUTHOR]

Background/Aims: Neutrophil extracellular traps (NETs) are known to play an important role in systemic lupus erythematosus (SLE) by triggering innate and adaptive immune responses. The molecular mechanisms responsible for their formation in SLE are still unclear. In this study, we aim to characterize the role of the receptor-interacting protein kinase-1 (RIPK1), a homologous serine/threonine kinase previously implicated in the regulation of necroptosis and tissue injury, in decreasing neutrophil death and formation of NETs, and to investigate the clinical implications of RIPK1 in SLE. Methods: Patients with SLE (n = 50) and healthy donors (n = 35) were enrolled in in vitro studies. Management of SLE patients was evaluated using the SLE disease activity index 2000 (SLEDAI-2K) score and laboratory variables. The mRNA level of RIPKs was measured by quantitative polymerase chain reaction (qPCR). Intracellular RIPK1 and RIPK3 production by peripheral blood leukocytes was detected by four-color flow cytometry and confirmed by automatic western blotting. TNF-α, IFN-γ, IL-1β, IL-2, IL-8, IL-18, and RIPK1 were measured by enzyme-linked immunosorbent assay. Cell death was assayed by Sytox green dye from peripheral neutrophils stimulated by RIPK-1-stabilizer necrostatin-1 (nec-1) and phorbol 12-myristate 13-acetate (PMA). Immunofluorescence staining and confocal microscopy were used to detect NET formation ex vivo. Quantification of NETs was determined by fluorescence spectrometry. Results: IFN-γ, IL-1β, IL-8, and IL-18 levels in serum were increased in SLE patients compared to controls. However, the expression of TNF-α, IL-2, and RIPK1 were decreased. In addition, we observed significant differences in the expression of RIPK1 in peripheral blood leukocytes. Of all the leukocytes, RIPK1 expression was significantly lower in neutrophils. Furthermore, we studied NETs formation in neutrophils of SLE with decreased RIPK1 expression, and these show increased susceptibility to NETosis, when stimulated with PMA and/or nec-1. Importantly, RIPK1 expression in neutrophils negatively correlated with ESR, CRP, 24-hour urine total protein, and the disease activity index in SLE. Conclusion: These data represent the first report of decreased RIPK1 expression in neutrophils of SLE patients and imply that RIPK1 may be involved in neutrophil death and NET formation. We suggest that RIPK1 is a potential biomarker to predict disease activity. [ABSTRACT FROM AUTHOR]

In this work, a high-specific-energy magnesium/water battery (Mg/H 2 O battery) combining Mg oxidation with hydrogen evolution reaction (HER) is developed for full-depth ocean application. With the optimized platinum loading associated with moderate Ni(OH) 2 on nickel foam, the performance can be increased obviously. Coupled with AZ91 Mg alloy anode, the specific energy of Mg/H 2 O battery reaches a dramatic value of 1003 W h kg −1 . Moreover, ultrahigh pressure of 1100 bar in the deep-sea simulated condition brings negligible effects on the performance of battery and electrodes. The influence of low temperature can be reduced to an acceptable level under the application at low discharge current density. Stable discharge of the battery for 100 days is also obtained. This work provides a new idea to supply power source with high specific energy, excellent environment adaptability, good safety and low cost for underwater application. [ABSTRACT FROM AUTHOR]

The microstructure of carbon materials in terms of its specific surface area and pore structure by its activation, are the key issues which determine the electrochemical performance of supercapacitors. In this work, we developed a particular chemical activation process assisted by nitrogen/sulfur co-doping for the preparation of hierarchical porous carbon materials with high specific surface area, aiming at improving the energy density of supercapacitors. The as-obtained hierarchical porous carbon materials exhibited both high Brunauer-Emmett-Teller surface area of up to 3652 m 2 g −1 for more ions adsorption and high porosity (2.61 cm 3 g −1 ) for rapid ion transport. Attributed to the synergistic effects of these two features, the porous carbon displays high gravimetric specific capacitance (324 F g −1 ) in KOH aqueous electrolyte with outstanding rate performance (73.3% capacitance retention at 100 A g −1 ). The symmetrical supercapacitor based on our hierarchical porous carbon displays a maximum specific energy of 9.76 Wh kg −1 and 94.5% retention over 10000 cycles at 15 A g −1 . This synthesis strategy is facile, low-cost and industrialized, which provide a promising route to prepare the hierarchical porous carbon materials for energy storage and renewable delivery devices. [ABSTRACT FROM AUTHOR]

A multiresidue method for the determination of 12 glucocorticoids (clobetasol propionate, budesonide, triamcinolone, triamcinolone acetonide, fludrocortisone acetate, flumethasone, beclomethasone, prednisone acetate, 6-α-methylprednisolone, hydrocortisone, cortisone, and prednisone) in bovine milk was developed using liquid chromatography with tandem mass spectrometry. Isoflupredone was used as an internal standard. Milk samples were treated with ethyl acetate to extract glucocorticoids and were frozen at −20°C for 6 h to precipitate fat. The extract was dried under nitrogen, and residues were dissolved in an acetonitrile/water solution. A further clean-up step was used by dispersive solid-phase extraction, with octadecyl silica and primary secondary amine as the absorbents. The recoveries of glucocorticoids spiked at 0.5, 1.0, 10.0 μg/kg ranged from 75.7 to 117.3%, except for clobetasol propionate and budesonide (16.1-49.5%). The limits of quantification were 0.01-0.5 μg/kg in milk. This method has been successfully applied in real samples. The results demonstrated that this method is simple, robust, and suitable for identification of glucocorticoid residues in milk. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS) is a lethal clinical entity that has become an emergency event with the outbreak of COVID-19. However, to date, there are no well-proven pharmacotherapies except dexamethasone. This study is aimed to evaluate IRAK4 inhibitors as a potential treatment for ARDS-cytokine release syndrome (CRS). We applied two IRAK4 inhibitors, BAY-1834845 and PF-06650833 to an inhaled lipopolysaccharide (LPS)-induced ARDS mouse model with control of high dose dexamethasone (10 mg/kg). Unexpectedly, although both compounds had excellent IC 50 on IRAK4 kinase activity, only BAY-1834845 but not PF-06650833 or high dose dexamethasone could significantly prevent lung injury according to a blinded pathology scoring. Further, only BAY-1834845 and BAY-1834845 combined with dexamethasone could effectively improve the injury score of pre-existed ARDS. Compared with PF-06650833 and high dose dexamethasone, BAY-1834845 remarkably decreased inflammatory cells infiltrating lung tissue and neutrophil count in BALF. BAY-1834845, DEX, and the combination of the two agents could decrease BALF total T cells, monocyte, and macrophages. In further cell type enrichment analysis based on lung tissue RNA-seq, both BAY-1834845 and dexamethasone decreased signatures of inflammatory cells and effector lymphocytes. Interestingly, unlike the dexamethasone group, BAY-1834845 largely preserved the signatures of naïve lymphocytes and stromal cells such as endothelial cells, chondrocytes, and smooth muscle cells. Differential gene enrichment suggested that BAY-1834845 downregulated genes more efficiently than dexamethasone, especially TNF, IL-17, interferon, and Toll-like receptor signaling. • IRAK4 inhibition is a potentially feasible treatment for ARDS. • BAY-1834845 shows unexpectedly discrepant efficacy in vivo with PF-06650833. • BAY-1834845 inhibits natural immunity signaling stronger than dexamethasone. [ABSTRACT FROM AUTHOR]

Iron-nitrogen-carbon (Fe-N-C) catalysts for oxygen reduction reaction (ORR) are promising candidates in fuel cell devices but the poor stability remains a grave challenge. The elimination of demetallation is pivotal for extending the life but still incapable due to the ambiguous mechanism. Herein, we show that the structure of FeN 4 site and its structural evolution during ORR has the significant influence. The end-of-test/in-situ Mössbauer spectroscopy and density functional theory study reveal that D1 mainly contributes to the ORR activity but suffers severe demetallation, which is likely due to the instability of FeN 4 C 8. The faster demetallation during ORR, especially at higher potential, can be attributed to the weaker coordination of FeN 4 induced by oxygenated intermediate and electric field according to ab initio molecular dynamics simulations. Finally, the binding energy of Fe-N bond is introduced to describe the influence of structure and structural evolution and give guidance to the improvement of stability. The influence of structure and structural evolution of active site on the demetallation of Fe-N-C is investigated by the end-of-test/in-situ Mössbauer spectroscopy and ab initio molecular dynamics simulation. [Display omitted] • The demetallation related to the degradation of Fe-N-C for ORR is studied. • The stability and activity of FeN 4 varied by structure are identified. • The effect of structural evolution of FeN 4 on demetallation is determined. • The stability and activity mapping of various active sites is exhibited. [ABSTRACT FROM AUTHOR]

The electronic regulation induces a weak adsorption strength of poisonous CO on active Pd nanoparticles, enabling the improvement of electrocatalytic activity for MOR. [Display omitted] • A synergistic catalyst comprised of Pd single atoms and nanoparticles was prepared. • Pd NPs /Pd-N x @C exhibits superior catalytic performance for MOR in alkaline media. • The EMSI between Pd SAs and matrix boosts the electron transfer at their interface. • The charge migration from Pd nanoparticles to the matrix is suppressed. • The adsorption strength of poisonous CO on the active Pd nanoparticles is weakened. For commercially viable direct methanol fuel cells, electrocatalysts play a crucial role in motivating the sluggish methanol oxidation reaction (MOR) over anode. Unfortunately, the large-scale applications of current MOR catalysts are hampered by their poor tolerance to poisoning and fast activity degradation. Herein, a unique composite catalyst comprised of partial Pd nanoparticles and partial Pd single atoms (Pd NPs /Pd-N x @C) is developed. The as-fabricated catalyst exhibits remarkable activity of 9.45 mA·cm−2 towards MOR in alkaline solution, which is 7.05 and 3.92 times that of commercial Pd/C and nanoparticle type (Pd NPs @C) electrocatalysts, respectively. Impressively, the Pd NPs /Pd-N x @C shows the highest long-time stability with 90.38% and 89.8% of the initial activity retained after 3600 s chronoamperometry (CA) test and 2000 cycles of cyclic voltammetry (CV) measurements with accelerated durability test (ADT), respectively. Combined with high-angle annular darkfield scanning transmission electron microscopy (HAADF-STEM), X-ray adsorption fine structure (XAFS) spectra and X-ray photoelectron spectroscopy (XPS) analyses, the superior performance of Pd NPs /Pd-N x @C can be ascribed to the synergistic effect from the Pd single atoms, N-doped carbon supports and Pd nanoparticles. Notably, the embedded Pd single atoms are liable to transfer electrons to the substrate due to the electronic metal-support interactions (EMSI) and the charge transfer between Pd nanoparticles and carbon supports is suppressed, inducing a weak adsorption strength of poisonous carbonous intermediate species on active Pd nanoparticles and improved poisoning tolerance in MOR process, which is verified by density functional theory (DFT) calculations as well as CO-stripping voltammetry experiments. This work not only contributes the first example of a synergistic catalyst between nanoparticles and single atoms for MOR but also deepens the knowledge on the metal-support interaction. [ABSTRACT FROM AUTHOR]

A fiber-reinforced composite membrane has been fabricated using a high-surface-energy substrate via a facile one-step doctor blading technique, which would be a perfect match for roll-to-roll process. The nanofiber mat based on sulfonated polyether-ether-ketone and polyvinylidene fluoride acting as reinforcement frame shows ultra-high surface energy, and enables efficient impregnation of perfluorosulfonated ionomer into porous substrate to form a uniform-layer structure with nanofibers interspersed throughout the composite membrane on the thickness direction. As a result, the fiber-reinforced composite membranes display enhanced mechanical stability and reduced swelling rate. With high packing density and continuous PFSI distribution, the as-prepared composite membranes perform better both on through-plane conductivity and cell performance under a low humidification than those of commercial membranes based on porous poly (tetra fluoroethylene). [Display omitted] • Membranes reinforced with a high-surface-energy substrate (sulfonated polyether-ether-ketone and polyvinylidene fluoride) were prepared as PRS by one-step doctor blading technique. • PRS demonstrates a uniform-layer structure unlike commercially used PTFE-reinforced membranes. • PRS performs better than commercially used PTFE-reinforced membranes in fuel cell under all humidity conditions and is significantly higher without humidification. [ABSTRACT FROM AUTHOR]

Abstract: A novel method for measuring effective diffusion coefficient of porous materials is developed. The oxygen concentration gradient is established by an air-breathing proton exchange membrane fuel cell (PEMFC). The porous sample is set in a sample holder located in the cathode plate of the PEMFC. At a given oxygen flux, the effective diffusion coefficients are related to the difference of oxygen concentration across the samples, which can be correlated with the differences of the output voltage of the PEMFC with and without inserting the sample in the cathode plate. Compared to the conventional electrical conductivity method, this method is more reliable for measuring non-wetting samples. [Copyright &y& Elsevier]

Atomically dispersed Fe-N-C catalyst is fabricated by a rational designed dual-MOFs strategy for efficient and low-cost DMFC application. • A dual-MOFs strategy is developed for the fabrication of atomically dispersed Fe-N-C catalyst. • The formation mechanism of the atomically dispersed Fe-N-C catalyst is well investigated. • The as-prepared catalyst demonstrates high ORR activity, excellent methanol tolerance and outstanding stability in acids. • The DMFC assembled with atomically dispersed Fe-N-C catalyst exhibits excellent performance. The rational design of highly efficient, low-cost and methanol-tolerant catalysts toward the oxygen reduction reaction (ORR) is urgently desired for the commercialization of direct methanol fuel cells (DMFCs). Herein, a novel Fe-N-C catalyst (ZIF/MIL-10-900) is derived from a mixture of ZIF-8 and MIL-101(Fe) and atomically dispersed FeN 4 structures are confirmed by Mössbauer spectra and X-ray absorption spectroscopy. Study on the pyrolysis procedure reveals that Fe atoms in FeN 4 are from MIL-101(Fe), while ZIF-8 acts as structural support and nitrogen sources. The as-prepared catalyst demonstrates a comparable ORR activity with the commercial Pt/C possessing a half-wave potential (E 1/2) of 0.78 V in acids, in combination with excellent methanol tolerance and stability. One of the highest peak power density of 83 mW cm−2 in DMFC (3 M CH 3 OH) by adopting ZIF/MIL-10-900 as cathode catalyst is obtained, which is 2.8-fold higher than that of the commercial Pt/C in the same operating condition. [ABSTRACT FROM AUTHOR]