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Selenium concentration of one spot urine sample cannot reflect selenium status during whole pregnancy. Studies on variations of urinary selenium concentration at different stages of pregnancy are limited. To assess variations of urinary selenium concentrations during three trimesters of pregnancy and to explore the influencing factors. This study included 2613 pregnant women from a birth cohort study (Wuhan, China) enrolled between October 2014 and October 2016. Selenium concentrations of urine samples collected at three trimesters were measured. We used a generalized linear mixed effects model to observe the changes in urinary selenium concentration during pregnancy and its influencing factors. The median value (range) of gestational weeks at urine sample collection was 11 (9−14), 24 (15−27), and 34 (28−41) respectively. Urine selenium concentration varied across trimesters (geometric mean: 16.34, 17.65 and 18.83 μg/g creatinine, respectively), with an upward trend (β = −0.145, 95%CI: −0.164, −0.126) (β = −0.066, 95%CI: −0.083, −0.048). The concentrations of urinary selenium increased with the increasing of educational level [ β (95%CI): ≤ 9 years = −0.105 (−0.163, −0.047); 10–12 years = −0.086(−0.126, −0.047); > 12 years = reference]. Pregnant women who rarely or only took multivitamins in the first trimester [ β (95% CI): rarely = −0.076 (−0.144, −0.007); only in the first three months of pregnancy = −0.104 (−0.170, −0.038); always = reference], or were not exposed to passive smoking during pregnancy（ β = −0.093 , 95% CI: − 0.173, − 0.014), or exercised three to four days per week for the first three months before delivery（ β = −0.074 , 95% CI: − 0.140, − 0.008) had lower urinary selenium concentrations. Pregnant women who took calcium supplements after the third month of pregnancy had higher urinary selenium levels（ β = 0.114, 95% CI: 0.059, 0.169). Urine selenium concentrations of pregnant women showed an upward trend across trimesters. Educational level, calcium or multivitamin supplementation, passive smoking, and physical exercise might impact urine selenium levels. [ABSTRACT FROM AUTHOR]

Abstract: Proliferation of nonlinear loads in power systems has increased harmonic pollution and deteriorated power quality. Passive filtering has typically been the standard technology for harmonic and reactive power compensation .With the advancements in power electronics, active filtering is being more widely considered given its flexibility and precise control. However, cost, complexity, and reliability are considered the major drawbacks of active filters. In this paper a new fuzzy logic is introduced to control the harmonic in the power system, which has more advantages such as simplicity, ease of application, flexibility, speed and ability to deal with imprecision and uncertainties .The introduction of fuzzy logic can not only reduce harmonic,but also correct the power factor. [Copyright &y& Elsevier]

In this work, a novel 3D graphene/Fe 3 O 4 (G-Fe 3 O 4) nanocomposite was prepared by a facile one-pot hydrothermal process used to be adulterated into the varnish as an anticorrosive and electromagnetic shielding paint. It is confirmed that the skeleton structure of graphene can effectively inhibit Fe 3 O 4 agglomeration by Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technique, and the G-Fe 3 O 4 nanocomposites can be well dispersed in the varnish for a longtime without settling. The graphene/Fe 3 O 4 composite varnish shows excellent corrosion resistance both in city water and seawater, besides its corrosion resistance is also superior to that of ordinary anti-rust paint. Moreover, the electromagnetic shielding test confirms that the as-prepared composite varnish shows well electromagnetic shielding performance. This new type of composite varnish has a broad application prospect to be used as urban exterior wall and ships paint. [ABSTRACT FROM AUTHOR]

In this work, visible light-responsive composite photocatalysts SrFe 2 O 4 /g-C 3 N 4 were simply prepared by ultrasonically dispersing and refluxing the mixture of SrFe 2 O 4 and g-C 3 N 4. The as-prepared composites exhibited remarkably higher photocatalytic activity than both pristine SrFe 2 O 4 and g-C 3 N 4 for degradation of Rhodamine B driven by visible light. Especially, the most efficient catalyst SrFe 2 O 4 /g-C 3 N 4 (1:1) with 1:1 mass ratio of SrFe 2 O 4 to g-C 3 N 4 can completely degradate 100 mL 10 mg/L RhB in 40 min. Furthermore, the catalyst could be magnetically separated easily for reuse and no obvious loss of activity was observed when reused in five consecutive runs. Visible light-responsive composite photocatalysts of strontium ferrite/graphitic carbon nitride, SrFe 2 O 4 /g-C 3 N 4 , were simply synthesized by ultrasonically dispersing and refluxing the mixture of SrFe 2 O 4 and g-C 3 N 4. The as-prepared composites were well characterized and their catalytic performances for photocatalytic Rhodamine B degradation were evaluated under visible-light irradiation. The composites catalysts exhibited remarkably higher activities than both pristine SrFe 2 O 4 and g-C 3 N 4 endowed by synergetic effect between the two moieties. Especially, the most efficient catalyst SrFe 2 O 4 /g-C 3 N 4 (1:1) with 1:1 mass ratio of SrFe 2 O 4 to g-C 3 N 4 can completely degradate RhB in 100 mL aqueous solution with concentration of 10 mg/L in 40 min. Furthermore, the catalyst can be facilely separated by external magnet for recycling and almost no decrease in its catalytic activity was observed after five runs reuse. [ABSTRACT FROM AUTHOR]

Graphical abstract In this work, Ca-doped spinel Co ferrites were prepared by a facile, mild and environment-friendly route. The samples exhibit remarkably high activities in the oxidation of cyclopentene using H 2 O 2 as green oxidant. The Ca-doped samples have shown greatly enhanced performances than the pristine CoFe 2 O 4. More interestingly, the products distribution showed strong dependence on the solvents, that is, special product can be obtained by selecting special solvent. The highest cyclopentene conversion of 100% and cyclopentenone selectivity of 99.5% was achieved with the catalyst sample Ca 0.3 Co 0.7 Fe 2 O 4 in DMF solvent. Abstract The calcium doped CoFe 2 O 4 spinels Ca x Co 1− x Fe 2 O 4 (x = 0, 0.1, 0.3, 0.5 and 0.7) were prepared by simple sol–gel auto-combustion method. The samples were characterized by X-ray diffractometry, Raman spectrometry, scanning and transmission electron microscopy, N 2 -physisorption and inductive coupled plasma-atomic emission spectroscopy. The samples have shown prominent activities in oxidation of cyclopentene using 30% hydrogen peroxide as oxidant. When compared to the pristine CoFe 2 O 4 , the Ca-doped ones were more efficient having a conversion ranging from 72.1% to 100% and a H 2 O 2 utilization efficiency range of 80.0–84.7%. When the calcium content was 0.3 and above, the cyclopentene was quantitatively converted to cyclopentenone at 60 °C for 8 h reaction. More interestingly, the catalyst has shown great solvent selectivity with respect to the product distribution. Finally, the catalyst can be easily separated magnetically for reuse and no obvious loss of activity was observed after five consecutive runs. [ABSTRACT FROM AUTHOR]

The initial corrosion resistance of ferritic stainless steels with various Cr and Mo levels in simulated fuel cell environments is evaluated using the HKD calculation method and electrochemical tests. HKD utilizes high-throughput DFT, KMC, and AIMD statistical coverage calculations to study passivation film development and ion/molecule adsorption behaviors, like O2-, F-, H 2 O, and OH-. Super-high Cr-containing Mo steel shows reliable corrosion resistance due to their stable structure and effective passivation film integrity at various F- concentrations and pH values. Furthermore, the impact of F- competes with O2-, influencing film formation as pH lowers and concentration rises. • The corrosion properties of ferritic stainless steel in the PEMFC environment. • HKD integrates high-throughput DFT, KMC, and AIMD. • The high-throughput DFT and KMC are applied to tailor the unit cell of stainless steel. • AIMD calculations provide passivation properties and elemental distribution in PEMFC environment. • The experiments confirm that SHCr-Mo maintains excellent corrosion resistance under PEMFC conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Innovating and proposing the DPWSIR model based on the DPSIR model. • Clarifying the toughness index for each stage of the DPWSIR model. • Using the G1-entropy weighting method to assign weights to evaluation indicators. • Analyzing the correlation between the criteria stage and the indicator stage indicators. • Providing support for improving the social-ecological resilience of arid cities in northwest China. Assessment of social-ecological system resilience is a reliable means of characterizing the system's ability to respond and recover in response to crisis events. This study takes Northwest China as the research area and aims to assess the spatiotemporal evolutionary trends of social-ecological system resilience levels. Driving force-Pressure-Meteorological constraint-State-Impact-Response(DPWSIR) model is proposed to construct the social-ecological system resilience evaluation system innovatively. The G1 entropy weight method is used to determine the index weight, and the comprehensive index method is used to calculate the social-ecological system resilience level values, evaluate the resilience of arid cities social-ecological systems in Northwest China from 2015 to 2021, and determine the resilience grades. The results demonstrate that: (1) The core status of regional central cities is highlighted, in general, the "center-periphery" spatial structure characteristics gradually stabilize. The resilience levels of regional central cities, such as Hohhot, Baotou, Xi'an, Lanzhou, Xining, Yinchuan, and Urumqi, are as high as 0.37, 0.43, 0.414, 0.41, 0.43, 0.58, and 0.39, respectively. (2) In the study area, the meteorological constraint resilience index showed a "flat-to-sudden decline" trend, with the inflection point of the sharp decline occurring in 2020. The decline in the resilience index value in arid cities is caused by the increase in precipitation and temperature, which is manifested as the result of "warming and humidification". (3) Meteorological factors, as the direct influencing factors of sandstorms, are the most critical to the assessment of the resilience of arid cities social-ecological systems. The relative percentage difference (RPD) is used to characterize the relative difference between the traditional model (DPSIR) and the improved model (DPWSIR). In areas for example Jinchang(29%), which is close to the dust sources and greatly affected by sandstorms, the differences in the social-ecological systems resilience are large and the RPD values are significant. Therefore, the DPWSIR model is more suitable for arid cities. This study provides scientific reference for the formulation of ecological environment protection policies and resilience improvement strategies for cities affected by sandstorms. [ABSTRACT FROM AUTHOR]

Water electrolysis is the most clean and high-efficiency technology for production of hydrogen, an ultimate clean energy in future. Highly efficient non-noble electrocatalysts for hydrogen evolution reaction (HER) are desirable for large scale production of hydrogen by water electrolysis. Especially, exposing as many active sites as possible is a vital way to improve activities of the catalysts. Herein, a series of new hydrangea like composite catalysts of ultrathin Mo 2 S 3 nanosheets assembled uprightly and interlacedly on N, S-dual-doped graphitic biocarbon spheres were facilely prepared. The unique structure endowed the catalysts highly exposed edge active sites and prominently high activities for HER. Especially, the optimized catalyst Mo 2 S 3 /NSCS-50 exhibited as low as 106 mV of overpotential at 10 mA/cm2 (denoted as ƞ 10). The catalyst also showed low Tafel slope of 53 mV/dec, low electron transfer resistance of 34 Ω and high stability evidenced by the result that the current density only attenuated 11.7% after 10 h i-t test. The catalyst has shown broad prospect for commercial application in water electrolysis. • New Mo 2 S 3 ultrathin nanosheets based catalysts have been fabricated for HER. • Mo 2 S 3 ultrathin nanosheets assembled uprightly and interlacedly on carbon spheres. • Hydrangea like composite catalysts were formed based on the above assembly. • The unique structure can provide plenty of exposed edge active sites. • The catalysts exhibited prominent activities and high stabilities for HER. [ABSTRACT FROM AUTHOR]

• A novel communication-efficient federated recommendation model is proposed. • A many-objective evolutionary method is used to achieve parameter reduction. • Recommended performances and communication cost are optimized simultaneously. The federated recommendation system (FedRS), which is the application of the recommendation system (RS) in federated learning, has been creatively developed as increasing attention has been paid to user privacy protection. However, traditional federated learning consumes excessive communication time and resource, which seriously limits the development of the FedRS. To reduce the communication cost and improve the recommendation performance of FedRS, an improved many-objective federated recommendation model with a novel parameter reduction strategy is proposed in this paper. The model aims to optimize the number of parameters shared between the server and client to improve communication efficiency in the federated process. Optimal parameter selection solutions can be obtained using the many-objective evolutionary algorithm (MaOEA), which can optimize the recommendation accuracy, novelty, diversity, and communication efficiency of FedRS simultaneously. Furthermore, the reference vector guided evolutionary algorithm (RVEA) was adopted to evaluate the proposed model. Experiments were performed on two famous recommendation datasets to examine the superiority of RVEA for the evaluation. The performance results indicated that the proposed model can not only provide accurate, diverse, and novel recommendations for the client, but can also realize efficient communication. [ABSTRACT FROM AUTHOR]

Abstract: The influence of NiO-doping on the microstructure and dielectric properties of CaCu3Ti4O12–xNiO (x=0, 0.003, 0.006, 0.010, 0.015, and 0.020) ceramics has been investigated using SEM, Raman spectra and dielectric spectrum measurements. The positron annihilation lifetime spectra (PALS) are used to investigate the influence of defects on the dielectric properties. The SEM results show that the grain morphology varies significantly with increasing NiO content. An appropriate small amount of NiO can promote the grain growth, which is beneficial to improve the dielectric properties in a CaCu3Ti4O12 (CCTO) system. Positron results show that there are vacancy-type defects in the experimental samples, and the concentration of the defect and the defect type both change with increasing NiO content. The effects of microstructure including the grain morphology and the vacancy defects on the mechanism of the dielectric properties by adding NiO are discussed. The results demonstrate the importance of the grain morphology and the characteristic of defects in controlling the electrical properties of CCTO ceramics. [Copyright &y& Elsevier]

Abstract: The M-doped GdBa2Cu3− x M x O7− δ (Mystems have been systemically investigated by means of XRD, SEM and Raman spectroscopy. The results show that the samples undergo an orthorhombic–tetragonal (O–T) phase transition near x =0.10 by Fe ions doping. Although all the Zn-doped samples remain orthorhombic structure, the changes of the lattice parameters in the Zn-doped samples may induce a structural distortion because of Jahn–Teller effect. The crystallite appearances alter perceptibly with the Fe/Zn doping contents. Meanwhile, the changes of the typical Raman models are discussed. The research has found that the Raman modes present distinctive behaviors by Zn or Fe ions doping, which strongly depend on the crystal structure, especially on O–T phase transition. The effects of structure phase transition and the changes of the phonon vibration on the mechanism of electrical transport properties by Fe and Zn doping in different Cu sites are also discussed. [Copyright &y& Elsevier]

Highly efficient multifunctional earth-abundant elements based electrocatalysts are key important for development of clean energy transformation technologies, such as metal-air batteries, fuel cells and water electrolysis. Herein, composite catalysts of N-doped carbon wrapping Co x P hollow spheres have been successfully prepared by pyrolysis of precursors from self-assembly of cobalt salt, terephthalic acid and PVP followed by carbonization and phosphatization in the presence of sodium hypophosphite. The resulted composites showed high specific surface areas, pore volumes and nitrogen contents, especially more than 47% of pyridinic-N. The electrocatalytic activity tests showed that the optimized Co x P-NC-420 sample exhibited superior multifunctional performances and high stabilities for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) under alkaline conditions. A low overpotential of 125/273 mV (at 10 mA cm−2) and Tafel slope of 66/81 mV dec−1 was obtained for HER and OER, respectively. As for ORR, as high as 0.860 V of half-wave potential was obtained, which is even 36 mV higher than that of Pt/C (20%). The catalyst also exhibited high practical performances on water electrolysis and Zn−air battery. Only 1.61 V of cell voltage was needed to reach 10 mA cm−2 for water electrolysis, and 1.374 V of open-circuit potential and 52 mW cm−2 of power density were obtained for Zn−air battery, which was 16 mW cm−2 higher than that of Pt/C (20%). Moreover, a highly effcient self-driven water electrolyzer has been designed with Co x P-NC-420 as both anode and cathode catalyst, powered by two-series-connected Co x P-NC-420-based Zn–air batteries. This work provides a new strategy for fabrication of non-precious multifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]