Capturing the electron-electron cusp with the coupling-constant averaged exchange-correlation hole: A case study for Hooke's atoms.

In density-functional theory, the exchange-correlation (XC) energy can be defined exactly through the coupling-constant (λ) averaged XC hole n̄xc(r,r'), representing the probability depletion of finding an electron at r' due to an electron at r. Accurate knowledge of n̄xc(r,r') has been crucial for developing XC energy density-functional approximations and understanding their performance for molecules and materials. However, there are very few systems for which accurate XC holes have been calculated since this requires evaluating the one- and two-particle reduced density matrices for a reference wave function over a range of λ while the electron density remains fixed at the physical (λ = 1) density. Although the coupled-cluster singles and doubles (CCSD) method can yield exact results for a two-electron system in the complete basis set limit, it cannot capture the electron-electron cusp using finite basis sets. Focusing on Hooke's atom as a two-electron model system for which certain analytic solutions are known, we examine the effect of this cusp error on the XC hole calculated using CCSD. The Lieb functional is calculated at a range of coupling constants to determine the λ-integrated XC hole. Our results indicate that, for Hooke's atoms, the error introduced by the description of the electron-electron cusp using Gaussian basis sets at the CCSD level is negligible compared to the basis set incompleteness error. The system-, angle-, and coupling-constant-averaged XC holes are also calculated and provide a benchmark against which the Perdew-Burke-Ernzerhof and local density approximation XC hole models are assessed.

Electrocatalytic Mechanism of Defect in Spinels for Water and Organics Oxidation.

Spinels display promising electrocatalytic ability for oxygen evolution reaction (OER) and organics oxidation reaction because of flexible structure, tunable component, and multifold valence. Unfortunately, limited exposure of active sites, poor electronic conductivity, and low intrinsic ability make the electrocatalytic performance of spinels unsatisfactory. Defect engineering is an effective method to enhance the intrinsic ability of electrocatalysts. Herein, the recent advances in defect spinels for OER and organics electrooxidation are reviewed. The defect types that exist in spinels are first introduced. Then the catalytic mechanism and dynamic evolution of defect spinels during the electrochemical process are summarized in detail. Finally, the challenges of defect spinel electrocatalysts are brought up. This review aims to deepen the understanding about the role and evolution of defects in spinel for electrochemical water/organics oxidation and provide a significant reference for the design of efficient defect spinel electrocatalysts.

Strengthening Fe(II)/Fe(III) Dynamic Cycling by Surface Sulfation to Achieve Efficient Electrochemical Uranium Extraction at Ultralow Cell Voltage.

Electrochemically mediated Fe(II)/Fe(III) redox-coupled uranium extraction can efficiently reduce the cell voltage of electrochemical uranium extraction (EUE). How to regulate the surface structure to enhance the uranium acyl ion adsorption capacity and strengthen the Fe(II)/Fe(III) redox cycle process is crucial for EUE. In this work, we developed surface sulfated nanoreduced iron (S-NRI) for EUE and exhibited improved properties for EUE at an ultralow cell voltage (-0.1 V). Compared with a nanoreduced iron (NRI) adsorbent, S-NRI displayed faster electrochemical extraction kinetics properties and higher extraction efficiency and capacity for uranium. In a more complex seawater electrolyte containing uranyl ion concentration ranging from 1 to 20 ppm, the removal efficiency could reach almost ∼100% after EUE for 24 h. At a higher 50 ppm uranium acyl ion concentration in a seawater electrolyte, S-NRI exhibited higher extraction capacity (755.03 mg/g), which is better than 528.53 mg/g of NRI at a cell voltage of -0.1 V. Outstanding EUE property could be attributed to the fact that sulfate species (M-SO42-) on the S-NRI surface not only enhanced selective adsorption of uranyl ions but also strengthened the Fe(II)/Fe(III) redox cycle, which accelerated electron transfer between Fe(II) and U(VI), promoted the regeneration of Fe(II) active sites, and finally enhanced the EUE property.

Selective Anchoring by Surface Sulfur Species Coupled with Rapid Interface Electron Transfer for Ultrahigh Capacity Extraction of Uranium from Seawater.

Improving the adsorption selectivity, enhancing the extraction capacity, and ensuring the structural stability of the adsorbent are the key to realize the high efficiency recovery of uranium. In this work, we utilized the strong Lewis acid-base interaction between S2- and U(VI)O22+ coupling rapid electron transfer at the MnS/U(VI)O22+ solid-liquid interface to achieve excellent selectivity, high adsorption capacity, and rapid extraction of uranium. The as-synthesized MnS adsorbent exhibited an ultrahigh uranium extraction capacity (2457.05 mg g-1) and a rapid rate constant (K = 9.11 × 10-4 g h-1 mg-1) in seawater with 100.7 ppm of UO2(NO3)2 electrolyte. The kinetic simulation reveals that this adsorption process is a chemical adsorption process and conforms to a pseudo-second-order kinetic model, indicating electron transfer at the MnS/U(VI)O22+ solid-liquid interface. The relevant (quasi) in situ spectroscopic characterization and theoretical calculation results further revealed that the outstanding uranium extraction property of MnS could be attributed to the highly selective UO22+ adsorption of MnS with lower adsorption energy as a result of the strong interaction between S2- and UO22+ and the rapid mass transfer and interface electron transfer from S2- and low-valent Mn(II) to U(VI)O22+.

Electrochemical-Mediated Regenerable FeII Active Sites for Efficient Uranium Extraction at Ultra-Low Cell Voltage.

Nano-reduced iron (NRI) is a promising uranium adsorbent due to its strong reducibility and good selectivity, but it still faces the challenges of slow kinetics, limited and non-renewable active sites. In this work, we realized high efficiency uranium extraction under ultra-low cell voltage (-0.1 V) in seawater with 20 ppm UO2 (NO3 )2 solution by coupling electrochemical mediated FeII /FeIII redox and uranium extraction. The adsorption capacity and extraction efficiency of NRI after electrochemical uranium extraction (EUE) could reach 452 mg/g and 99.1 %, respectively. Combined with quasi-operando/operando characterization technologies, we clarified the mechanism of EUE and revealed that continuously regenerating FeII active sites by electroreduction could significantly enhance the property of EUE. This work here provides a new electrochemical mediated and low energy consumption uranium extraction strategy which also provides a reference for other metal resource recovery.

Vertex effects in describing the ionization energies of the first-row transition-metal monoxide molecules.

The GW approximation is considered to be the simplest approximation within Hedin's formulation of many-body perturbation theory. It is expected that some of the deficiencies of the GW approximation can be overcome by adding the so-called vertex corrections. In this work, the recently implemented G0W0Γ0 (1) scheme, which incorporates the vertex effects by adding the full second-order self-energy correction to the GW self-energy, is applied to a set of first-row transition-metal monoxide (TMO) anions. Benchmark calculations show that results obtained by G0W0Γ0 (1) on top of the B3LYP hybrid functional starting point (SP) are in good agreement with experiment data, giving a mean absolute error of 0.13 eV for a testset comprising the ionization energies (IEs) of 27 outer valence molecular orbitals (MOs) from nine TMO anions. A systematic SP-dependence investigation by varying the ratio of the exact exchange (EXX) component in the PBE0-type SP reveals that, for G0W0Γ0 (1), the best accuracy is achieved with 20% EXX. Further error analysis in terms of the orbital symmetry characteristics (i.e., σ, π, or δ) in the testset indicates the best amount of EXX in the SP for G0W0Γ0 (1) calculations is independent of MO types, and this is in contrast with the situation in G0W0 calculations, where the best EXX ratio varies for different classes of MOs. Despite its success in describing the absolute IE values, we, however, found that G0W0Γ0 (1) faces difficulties in describing the energy separations between certain states of interest, worsening the already underestimated G0W0 predictions.

Beryllium and Magnesium Metal Clusters: New Globally Stable Structures and G0W0 Calculations.

We study the structural and electronic properties of beryllium (Be) and magnesium (Mg) clusters for sizes 2-20 using a two-step approach. In the first step, a global search of the stable and low-lying metastable isomer structures is carried out on the basis of first-principles potential energy surfaces at the level of the generalized gradient approximation (GGA) of density functional theory (DFT). In the second step, vertical ionization potentials (VIPs) and energy gaps between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) are determined using the G0W0 methods for up to the fourth-lowest-energy isomers. Novel globally lowest-energy isomer structures are identified for Be14, Mg14, and Mg16 clusters. The van der Waals interactions are found to have a stronger influence on Mg clusters than on Be clusters. A second-difference analysis for both the binding energies and HOMO-LUMO gaps reveals a close relationship between the structural stability and chemical hardness for both types of clusters.

Platinum Modulates Redox Properties and 5-Hydroxymethylfurfural Adsorption Kinetics of Ni(OH)2 for Biomass Upgrading.

Nickel hydroxide (Ni(OH)2 ) is a promising electrocatalyst for the 5-hydroxymethylfurfural oxidation reaction (HMFOR) and the dehydronated intermediates Ni(OH)O species are proved to be active sites for HMFOR. In this study, Ni(OH)2 is modified by platinum to adjust the electronic structure and the current density of HMFOR improves 8.2 times at the Pt/Ni(OH)2 electrode compared with that on Ni(OH)2 electrode. Operando methods reveal that the introduction of Pt optimized the redox property of Ni(OH)2 and accelerate the formation of Ni(OH)O during the catalytic process. Theoretical studies demonstrate that the enhanced Ni(OH)O formation kinetics originates from the reduced dehydrogenation energy of Ni(OH)2 . The product analysis and transition state simulation prove that the Pt also reduces adsorption energy of HMF with optimized adsorption behavior as Pt can act as the adsorption site of HMF. Overall, this work here provides a strategy to design an efficient and universal nickel-based catalyst for HMF electro-oxidation, which can also be extended to other Ni-based catalysts such as Ni(HCO3 )2 and NiO.

Unveiling the Electrooxidation of Urea: Intramolecular Coupling of the N-N Bond.

The nitrogenous nucleophile electrooxidation reaction (NOR) plays a vital role in the degradation and transformation of available nitrogen. Focusing on the NOR mediated by the ß-Ni(OH)2 electrode, we decipher the transformation mechanism of the nitrogenous nucleophile. For the two-step NOR, proton-coupled electron transfer (PCET) is the bridge between electrocatalytic dehydrogenation from ß-Ni(OH)2 to ß-Ni(OH)O, and the spontaneous nucleophile dehydrogenative oxidation reaction. This theory can give a good explanation for hydrazine and primary amine oxidation reactions, but is insufficient for the urea oxidation reaction (UOR). Through operando tracing of bond rupture and formation processes during the UOR, as well as theoretical calculations, we propose a possible UOR mechanism whereby intramolecular coupling of the N-N bond, accompanied by PCET, hydration and rearrangement processes, results in high performance and ca. 100 % N2 selectivity. These discoveries clarify the evolution of nitrogenous molecules during the NOR, and they elucidate fundamental aspects of electrocatalysis involving nitrogen-containing species.

Operando Identification of the Dynamic Behavior of Oxygen Vacancy-Rich Co3O4 for Oxygen Evolution Reaction.

The exact role of a defect structure on transition metal compounds for electrocatalytic oxygen evolution reaction (OER), which is a very dynamic process, remains unclear. Studying the structure-activity relationship of defective electrocatalysts under operando conditions is crucial for understanding their intrinsic reaction mechanism and dynamic behavior of defect sites. Co3O4 with rich oxygen vacancy (VO) has been reported to efficiently catalyze OER. Herein, we constructed pure spinel Co3O4 and VO-rich Co3O4 as catalyst models to study the defect mechanism and investigate the dynamic behavior of defect sites during the electrocatalytic OER process by various operando characterizations. Operando electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) implied that the VO could facilitate the pre-oxidation of the low-valence Co (Co2+, part of which was induced by the VO to balance the charge) at a relatively lower applied potential. This observation confirmed that the VO could initialize the surface reconstruction of VO-Co3O4 prior to the occurrence of the OER process. The quasi-operando X-ray photoelectron spectroscopy (XPS) and operando X-ray absorption fine structure (XAFS) results further demonstrated the oxygen vacancies were filled with OH• first for VO-Co3O4 and facilitated pre-oxidation of low-valence Co and promoted reconstruction/deprotonation of intermediate Co-OOH•. This work provides insight into the defect mechanism in Co3O4 for OER in a dynamic way by observing the surface dynamic evolution process of defective electrocatalysts and identifying the real active sites during the electrocatalysis process. The current finding would motivate the community to focus more on the dynamic behavior of defect electrocatalysts.

Optimal Geometrical Configuration of Cobalt Cations in Spinel Oxides to Promote Oxygen Evolution Reaction.

MgCo2 O4 , CoCr2 O4 , and Co2 TiO4 were selected, where only Co3+ in the center of octahedron (Oh), Co2+ in the center of tetrahedron (Td), and Co2+ in the center of Oh, can be active sites for the oxygen evolution reaction (OER). Co3+ (Oh) sites are the best geometrical configuration for OER. Co2+ (Oh) sites exhibit better activity than Co2+ (Td). Calculations demonstrate the conversion of O* into OOH* is the rate-determining step for Co3+ (Oh) and Co2+ (Td). For Co2+ (Oh), it is thermodynamically favorable for the formation of OOH* but difficult for the desorption of O2 . Co3+ (Oh) needs to increase the lowest Gibbs free energy over Co2+ (Oh) and Co2+ (Td), which contributes to the best activity. The coexistence of Co3+ (Oh) and Co2+ (Td) in Co3 O4 can promote the formation of OOH* and decrease the free-energy barrier. This work screens out the optimal geometrical configuration of cobalt cations for OER and gives a valuable principle to design efficient electrocatalysts.

Defects-Induced In-Plane Heterophase in Cobalt Oxide Nanosheets for Oxygen Evolution Reaction.

Cobalt oxides as efficient oxygen evolution reaction (OER) electrocatalysts have received much attention because of their rich reserves and cheap cost. There are two common cobalt oxides, Co3 O4 (spinel phase, stable but poor intrinsic activity) and CoO (rocksalt phase, active but easily be oxidatized). Constructing Co3 O4 /CoO heterophase can inherit both characteristic features of each component and form a heterophase interface facilitating charge transfer, which is believed to be an effective strategy in designing excellent electrocatalysts. Herein, an atomic arrangement engineering strategy is applied to improve electrocatalytic activity of Co3 O4 for the OER. With the presence of oxygen vacancies, cobalt atoms at tetrahedral sites in Co3 O4 can more easily diffuse into interstitial octahedral sites to form CoO phase structure as revealed by periodic density functional theory computations. The Co3 O4 /CoO spinel/rocksalt heterophase can be in situ fabricated at the atomic scale in plane. The overpotential to reach 10 mA cm-2 of Co3 O4 /CoO is 1.532 V, which is 92 mV smaller than that of Co3 O4 . Theoretical calculations confirm that the excellent electrochemical activity is corresponding to a decline in average p-state energy of adsorbed-O on the Co3 O4 /CoO heterophase interface. The reaction Gibbs energy barrier has been significantly decreased with the construction of the heterophase interface.

Tuning Surface Electronic Configuration of NiFe LDHs Nanosheets by Introducing Cation Vacancies (Fe or Ni) as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction.

Intrinsically inferior electrocatalytic activity of NiFe layered double hydroxides (LDHs) nanosheets is considered as a limiting factor to inhibit the electrocatalytic properties for oxygen evolution reaction (OER). Proper defect engineering to tune the surface electronic configuration of electrocatalysts may significantly improve the intrinsic activity. In this work, the selective formation of cation vacancies in NiFe LDHs nanosheets is successfully realized. The as-synthesized NiFe LDHs-VFe and NiFe LDHs-VNi electrocatalysts show excellent activity for OER, mainly attributed to the introduction of rich iron or nickel vacancies in NiFe LDHs nanosheets, which efficiently tune the surface electronic structure increasing the adsorbing capacity of OER intermediates. Density functional theory (DFT) computational results also further indicate that the OER catalytic performance of NiFe LDHs can be pronouncedly improved by introducing Fe or Ni vacancies.

Salvianolic Acid B Ameliorates Cognitive Deficits Through IGF-1/Akt Pathway in Rats with Vascular Dementia.

BackgroundAims: Salvianolic acid B (SalB) is a natural polyphenolic compound enriched in Salvia miltiorrhiza Bunge. Our study was designed to explore the role of Sal B on cognitive impairment in vascular dementia (VD) model rats, as well as its possible molecular mechanisms. METHODS: Rats were randomly divided into four groups (n = 15 for each group): Control group, Sal B group (normal Sprague Dawley rats treated with Sal B), VD group and VD + Sal B group. The VD group rats were established by permanent bilateral common carotid artery occlusion (BCCAO). Animals in the Control and Sal B group received the same operation without bilateral common carotid arteries occlusion. The animals in Sal B group and VD + Sal B group received Sal B (20 mg/kg) orally once a day for consecutive 6 weeks. We investigated the effects of SalB on BCCAO-induced cognitive deficits rats models via the Morris water maze experiment. To explore the mechanisms of Sal B on cognitive function, we detected the expression of IGF-1, Akt and p-Akt, and the rate of cell apoptosis in CA1 region. RESULTS: Our results observed that hippocampal IGF-1 was decreased in VD model rats, while SalB reversed the alteration of IGF-1 levels. The expression of hippocampal Akt showed no significant difference between control and VD group, however, p-Akt level was significantly decreased in VD group. After 6 weeks of SalB treatment, p-Akt level was significantly increased. A large number of apoptotic neurons were found in VD model rats, while SalB prevented apoptosis of hippocampal neurons in CA1 region in VD model rats. CONCLUSION: SalB significantly ameliorated cognitive deficits in BCCAO-induced VD model rats. The potential mechanism underlying the protective effects may be mediated through IGF-1/Akt pathway.

Chronic Stress Contributes to Cognitive Dysfunction and Hippocampal Metabolic Abnormalities in APP/PS1 Mice.

BACKGROUND/AIMS: Stress response is determined by the brain, and the brain is a sensitive target for stress. Our previous experiments have confirmed that once the stress response is beyond the tolerable limit of the brain, particularly that of the hippocampus, it will have deleterious effects on hippocampal structure and function; however, the metabolic mechanisms for this are not well understood. METHODS: Here, we used morris water maze, elisa and gas chromatography-time of flight/mass spectrometry to observe the changes in cognition, neuropathology and metabolomics in the hippocampus of APP/PS1 mice and wild-type (C57) mice caused by chronic unpredictable mild stress (CUMS), we also further explored the correlation between cognition and metabolomics. RESULTS: We found that 4 weeks of CUMS aggravated cognitive impairment and increased amyloid-ß deposition in APP/PS1 mice, but did not affect C57 mice. Under non-stress conditions, compared with C57 mice, there were 8 different metabolites in APP/PS1 mice. However, following CUMS, 3 different metabolites were changed compared with untreated C57 mice. Compared to APP/PS1 mice, there were 7 different metabolites in APP/PS1+CUMS mice. Among these alterations, 3-hydroxybutyric acid, valine, serine, beta-alanine and o-phosphorylethanolamine, which are involved in sphingolipid metabolism, synthesis and degradation of ketone bodies, and amino acid metabolism. CONCLUSION: The results indicate that APP/PS1 mice are more vulnerable to stress than C57 mice, and the metabolic mechanisms of stress-related cognitive impairment in APP/PS1 mice are related to multiple pathways and networks, including sphingolipid metabolism, synthesis and degradation of ketone bodies, and amino acid metabolism.

Layered Double Hydroxide Nanosheets with Multiple Vacancies Obtained by Dry Exfoliation as Highly Efficient Oxygen Evolution Electrocatalysts.

Layered double hydroxides (LDHs) with two-dimensional lamellar structures show excellent electrocatalytic properties. However, the catalytic activity of LDHs needs to be further improved as the large lateral size and thickness of the bulk material limit the number of exposed active sites. However, the development of efficient strategies to exfoliate bulk LDHs into stable monolayer LDH nanosheets with more exposed active sites is very challenging. On the other hand, the intrinsic activity of monolayer LDH nanosheets can be tuned by surface engineering. Herein, we have exfoliated bulk CoFe LDHs into ultrathin LDH nanosheets through Ar plasma etching, which also resulted in the formation of multiple vacancies (including O, Co, and Fe vacancies) in the ultrathin 2D nanosheets. Owing to their ultrathin 2D structure, the LDH nanosheets expose a greater number of active sites, and the multiple vacancies significantly improve the intrinsic activity in the oxygen evolution reaction (OER).

Effects of Chronic Stress on Cognition in Male SAMP8 Mice.

BACKGROUND/AIMS: Chronic stress can lead to cognitive impairment. Senescence-accelerated mouse prone 8 (SAMP8) is a naturally occurring animal model that is useful for investigating the neurological mechanisms of Alzheimer's disease. Here we investigated the impact and mechanisms of chronic stress on cognition in male SAMP8 mice. METHODS: Male 6-month- old SAMP8 and SAMR1 (senescence-accelerated mouse resistant 1) mice strains were randomly divided into 4 groups. Mice in the unpredictable chronic mild stress (UCMS) groups were exposed to diverse stressors for 4 weeks. Then, these mice performed Morris water maze (MWM) test to assess the effect of UCMS on learning and memory. To explore the neurological mechanisms of UCMS on cognition in mice, we evaluated changes in the expression of postsynaptic density 95 (PSD95) and synaptophysin (SYN), which are essential proteins for synaptic plasticity. Five mice from each group were randomly chosen for reverse transcription polymerase chain reaction (RT-PCR) and western blotting analysis of SYN and PSD95. RESULTS: The Morris water maze experiment revealed that the cognitive ability of the SAMP8 mice decreased with brain aging, and that chronic stress aggravated this cognitive deficit. In addition, chronic stress decreased the mRNA and protein expression of SYN and PSD95 in the hippocampus of the SAMP8 mice; however, the SAMR1 mice were unaffected. CONCLUSION: Our results demonstrate that decreased cognition and synaptic plasticity are related to aging. Moreover, we show that chronic stress aggravated this cognitive deficit and decreased SYN and PSD95 expression in the SAMP8 mice. Furthermore, the SAMP8 mice were more vulnerable to the detrimental effects of chronic stress on cognition than the SAMR1 mice. Our results suggest that the neurological mechanisms of chronic stress on cognition might be associated with a decrease in hippocampal SYN and PSD95 expression, which is critical for structural synaptic plasticity.

Chronic high-frequency repetitive transcranial magnetic stimulation improves age-related cognitive impairment in parallel with alterations in neuronal excitability and the voltage-dependent Ca2+ current in female mice.

Chronic high-frequency repetitive transcranial magnetic stimulation (rTMS) is a noninvasive method to increase the excitability of neurons, and it induces long-term effects that can improve symptoms related to neurodegenerative diseases, including cognitive ability. The present study was undertaken to identify the mechanism by which rTMS improves cognitive impairments in mice. The novel object recognition test in vivo was used to evaluate the cognitive function of the mice. Whole-cell patch-clamp recordings were used to evaluate the neuronal excitability, including the resting membrane potential, the number of action potentials induced by depolarized current, after-hyperpolarization, and the voltage-dependent Ca(2+) current in hippocampal slices. We found that the aged mice showed impairments in cognitive function, and high-frequency (25Hz) rTMS for 14 consecutive-days ameliorated the impairments. Whole-cell patch-clamp recordings showed that, compared to matured mice, the hippocampal CA1 pyramidal neurons of aged mice showed significantly hyperpolarized resting membrane potential, significantly decreased numbers of action potentials after injection of depolarizing current, and significantly increased after-hyperpolarization after an action potential. The exposure to high-frequency rTMS significantly improved the above deficits in the neuronal excitability in the aged rTMS mice. Consistent with the above changes, the exposure to high-frequency rTMS also significantly decreased the voltage-dependent Ca(2+) current of the neurons compared with the aged sham mice. These data suggested that the rTMS could improve the age-related cognitive impairment in parallel with regulating the neuronal excitability and modifying the voltage-dependent Ca(2+) channels.

[Status of exercise and sedentary activities in the leisure time among third and fourth grade pupils in three cities of Shandong province].

OBJECTIVE: To analyze the status and the influence factors of exercise and sedentary activities in the leisure time among third and fourth grade pupils in Qingdao, Tai' an and Yantai city of Shandong province. METHODS: With random cluster sampling, a total of 2283 primary students were selected from three cities of Shandong province. Questionnaires were used to collect the information on their exercise, sedentary activities. RESULTS: In the past week the participation rate of exercise in the leisure time among the pupils was 65.9%. Among the pupils who participated exercise, the average days of moderate and high-intensity exercise was four, and the average daily exercise time was 30 minutes. The average time of sedentary activities in the leisure time was 0.9 h/d, and the rate of 2 hours and over per day of sedentary activities was 13.6%. Pupils participating the exercise was related to their area, gender, their satisfaction of their body image and their parents' exercise. Their sedentary patterns was related to their understanding of their own body weight and their parents' sedentary behavior. CONCLUSION: Intervention related to physical activity should be strengthened among pupils and their parents to promote their physical activity level.

Electrochemistry-assisted in-situ regeneration of oxygen vacancies and Ti(III) active sites for persistent uranium recovery at a low potential.

Electrochemical uranium extraction (EUE) from seawater is a very promising strategy, but its practical application is hindered by the high potential for electrochemical system, as well as the low selectivity, efficiency, and poor stability of electrode. Herein, we developed creatively a low potential strategy for persistent uranium recovery by electrochemistry-assisted in-situ regeneration of oxygen vacancies and Ti(III) active sites coupled with indirect reduction of uranium, finally achieving high selectivity, efficient and persistent uranium recovery. As-designed titanium dioxide rich in oxygen vacancies (TiO2-VO) electrode displayed an EUE efficiency of ∼99.9 % within 180 min at a low potential of 0.09 V in simulated seawater with uranium of 5∼20 ppm. Moreover, the TiO2-VO electrode also showed high selectivity (89.9 %) to uranium, long-term cycling stability and antifouling activity in natural seawater. The excellent EUE property was attributed to the fact that electrochemistry-assisted in-situ regeneration of oxygen vacancies and Ti(III) active sites enhanced EUE cycling process and achieved persistent uranium recovery. The continuous regeneration of oxygen vacancies not only reduced the adsorption energy of U(VI)O22+ but also serve as a storage and transportation channel for electrons, accelerating electron transfer from Ti(III) to U(VI) at solid-liquid interface and promoting EUE kinetic rate.