Pandemics have become more frequent and more complex during the twenty-first century. Posttraumatic stress disorder (PTSD) following pandemics is a significant public health concern. We sought to ...provide a reliable estimate of the worldwide prevalence of PTSD after large-scale pandemics as well as associated risk factors, by a systematic review and meta-analysis. We systematically searched the MedLine, Embase, PsycINFO, Web of Science, CNKI, WanFang, medRxiv, and bioRxiv databases to identify studies that were published from the inception up to August 23, 2020, and reported the prevalence of PTSD after pandemics including sudden acute respiratory syndrome (SARS), H1N1, Poliomyelitis, Ebola, Zika, Nipah, Middle Eastern respiratory syndrome coronavirus (MERS-CoV), H5N1, and coronavirus disease 2019 (COVID-19). A total of 88 studies were included in the analysis, with 77 having prevalence information and 70 having risk factors information. The overall pooled prevalence of post-pandemic PTSD across all populations was 22.6% (95% confidence interval (CI): 19.9-25.4%, I
: 99.7%). Healthcare workers had the highest prevalence of PTSD (26.9%; 95% CI: 20.3-33.6%), followed by infected cases (23.8%: 16.6-31.0%), and the general public (19.3%: 15.3-23.2%). However, the heterogeneity of study findings indicates that results should be interpreted cautiously. Risk factors including individual, family, and societal factors, pandemic-related factors, and specific factors in healthcare workers and patients for post-pandemic PTSD were summarized and discussed in this systematic review. Long-term monitoring and early interventions should be implemented to improve post-pandemic mental health and long-term recovery.
Sodium storage capacity, mobility, and volume change during sodiation on the surfaces of interlayer-expanded Ti3C2 MXenes are investigated using ab initio density functional theory. The theoretical ...results reveal that the interlayer-expanded bare, F-, O-, and OH-functionalized Ti3C2 MXenes exhibit low barriers for sodium diffusion and small changes of lattice constant during sodiation. In addition, enlarged interlayer distance enables the stable multilayer adsorption on the bare and O-functionalized Ti3C2 MXenes and therefore significantly enhances their theoretical capacities. Both bare and O-functionalized Ti3C2 MXenes are predicted to be prospective anode materials for sodium-ion batteries with high theoretical capacities, fast discharge/charge rates, and good cycling performances. The present results provide a new route to improve the battery performances of anode materials based on MXene intercalation hosts.
Chemical modification of electrode materials by heteroatom dopants is crucial for improving storage performance in rechargeable batteries. Electron configurations of different dopants significantly ...influence the chemical interactions inbetween and the chemical bonding with the host material, yet the underlying mechanism remains unclear. We revealed competitive doping chemistry of Group IIIA elements (boron and aluminum) taking nickel‐rich cathode materials as a model. A notable difference between the atomic radii of B and Al accounts for different spatial configurations of the hybridized orbital in bonding with lattice oxygen. Density functional theory calculations reveal, Al is preferentially bonded to oxygen and vice versa, and shows a much lower diffusion barrier than BIII. In the case of Al‐preoccupation, the bulk diffusion of BIII is hindered. In this way, a B‐rich surface and Al‐rich bulk is formed, which helps to synergistically stabilize the structural evolution and surface chemistry of the cathode.
A model study has been performed on Group IIIA element (boron and aluminum) co‐doped high‐nickel layered oxide cathode materials to understand competitive doping chemistry. A notable difference between the atomic radii of B and Al accounts for different spatial configurations of the hybridized orbital in bonding with lattice oxygen, resulting in the formation of a B‐rich surface and an Al‐rich bulk.
Abstract
We present the results from a spectroscopic monitoring campaign to obtain reverberation mapping measurements and investigate the broad-line region (BLR) kinematics for active galactic nuclei ...(AGNs) of Mrk 817 and NGC 7469. This campaign was undertaken with the Lijiang 2.4 m telescope. The median spectroscopic sampling is 2.0 days for Mrk 817 and 1.0 day for NGC 7469. We detect time lags of the broad emission lines, including H
β
, H
γ
, He
ii,
and He
i
for both AGNs, including Fe
ii
for Mrk 817 with respect to the varying AGN continuum at 5100 Å. Investigating the relationship between line widths and time lags of the broad emission lines, we find that the BLR dynamics of Mrk 817 and NGC 7469 are consistent with the virial prediction. We estimate the masses of central supermassive black holes (SMBHs) and the accretion rates of both AGNs. Using the data of this campaign, we construct the velocity-resolved lag profiles of the broad H
γ
, H
β
, and He
i
lines for Mrk 817, which show almost the same kinematic signatures in that the time lags in the red wing are slightly larger than the time lags in the blue wing. For NGC 7469, we only clearly construct the velocity-resolved lag profiles of the broad Hγ and Hβ, which show very similar kinematic signatures to the BLR of Mrk 817. These signatures indicate that the BLR of Keplerian motion in both AGNs seemingly has outflowing components during the monitoring period. We discuss the kinematics of the BLR and the measurements, including SMBH mass and accretion rates.
Metal sulfides with excellent redox reversibility and high capacity are very promising electrode materials for sodium‐ion batteries. However, their practical application is still hindered by the poor ...rate capability and limited cycle life. Herein, a template‐based strategy is developed to synthesize nitrogen‐doped carbon‐coated Cu9S5 bullet‐like hollow particles starting from bullet‐like ZnO particles. With the structural and compositional advantages, these unique nitrogen‐doped carbon‐coated Cu9S5 bullet‐like hollow particles manifest excellent sodium storage properties with superior rate capability and ultra‐stable cycling performance.
Sodium storage: Bullet‐like Cu9S5 hollow particles coated with a layer of nitrogen‐doped carbon are synthesized by a template‐based strategy. Their structure and composition allow these carbon‐coated Cu9S5 hollow bullets to exhibit enhanced sodium storage performance in terms of excellent rate capability and ultra‐stable cycle life.
Antimony‐based electrode materials with high specific capacity have aroused considerable interest as anode materials for sodium‐ion batteries (SIBs). Herein, we develop a template‐engaged ...ion‐exchange method to synthesize Sb2Se3 microclips, and the as‐obtained Sb2Se3 microclips are further in situ coated with polypyrrole (PPy). Benefiting from the structural and compositional merits, these PPy‐coated Sb2Se3 microclips exhibit enhanced sodium‐storage properties in terms of high reversible capacity, superior rate capability, and stable cycling performance.
The PPy who loved me: PPy‐coated Sb2Se3 microclips are synthesized by a simple ion‐exchange method and subsequent in situ polypyrrole (PPy) coating. With their unique structural and composition, these PPy‐coated Sb2Se3 microclips exhibit enhanced sodium‐storage performance in terms of high specific capacity, excellent rate capability, and good cycling stability.
Electrode materials based on electrochemical conversion reactions have received considerable interest for high capacity anodes of sodium‐ion batteries. However, their practical application is greatly ...hindered by the poor rate capability and rapid capacity fading. Tuning the structure at nanoscale and increasing the conductivity of these anode materials are two effective strategies to address these issues. Herein, a two‐step ion‐exchange method is developed to synthesize hierarchical Cu‐doped CoSe2 microboxes assembled by ultrathin nanosheets using Co–Co Prussian blue analogue microcubes as the starting material. Benefitting from the structural and compositional advantages, these Cu‐doped CoSe2 microboxes with improved conductivity exhibit enhanced sodium storage properties in terms of good rate capability and excellent cycling performance.
Hierarchical Cu‐doped CoSe2 microboxes are synthesized by a two‐step sequential ion‐exchange strategy using Co–Co Prussian blue analogue microcubes as precursors. With their structural and compositional advantages, these unique Cu‐doped CoSe2 microboxes exhibit enhanced sodium‐storage performance in terms of high specific capacity, excellent rate capability, and long cycle life.
Electrochemical synthesis of hydrogen peroxide (H2O2) through 2e– oxygen reduction reaction is an effective approach to replace anthraquinone process. However, most reported electrocatalysts work ...effectively in alkaline medium in which H2O2 will easily decompose into water. It is still of great challenge to develop cost‐effective electrocatalysts with high activity and selectivity for electrocatalytic H2O2 production in acidic media. Herein, it is first theoretically demonstrated that the adsorption energy of OOH* intermediate on carbon can be optimized by embedding Co nanoparticles (Co NPs) and tuning oxygen‐containing functional groups, ensuring high activity and selectivity. Guided by density functional theory calculations, highly porous open carbon nanocages with embedded Co NPs are designed and synthesized by template‐engaged method. The pyrolysis temperature can effectively modulate the electronic and pore structure of carbon nanocages. Impressively, the optimized carbon nanocages synthesized at 700 °C (P‐Co@C‐700) with highest percentage of –C–O–C group and defects, largest specific surface area (1351 m2 g–1), and mesoporous structure exhibit high selectivity up to 94% toward H2O2 production in 0.1 m HClO4. Furthermore, the P‐Co@C‐700 nanocages display promising application for efficient electro‐Fenton degradation of model organic pollutant.
The density functional theory calculations predict that the adsorption energy of OOH* on carbon can be optimized by embedding Co nanoparticles and tuning oxygen‐containing functional groups for the electrosynthesis of H2O2. Guided by calculations, open carbon nanocages with optimized electronic and pore structures are synthesized, manifesting high selectivity up to 94% for H2O2 synthesis in 0.1 m HClO4.
Electrocatalytic nitrate (NO3−) reduction reaction (NITRR) is an inspiring route for ammonia (NH3) synthesis at ambient condition. The metallic Cu‐based material with low cost and high activity is ...one of the most promising electrocatalysts for NITRR. However, due to the weaker atomic H*‐providing capacity, the produced intermediate—nitrite tends to accumulate on its surface, leading to unsatisfactory NH3 selectivity and Faradic efficiency (FE). Herein, a novel and facile O2/Ar plasma oxidation and subsequent electro‐reduction strategy is developed to synthesize a kind of metastable phase Cu. Excitingly, the metastable phase Cu demonstrates superior NITRR performance to conventional phase Cu with high NH4+ selectivity (97.8%) and FE (99.8%). Density function theory (DFT) calculations reveal that the upshift of the d‐band center to near the Fermi level in metastable phase Cu contributes to the enhanced activity, while the relatively strong adsorption of H* facilitates the conversion from NO2*/NO* to NOOH*/NOH* and thus ensures high selectivity and FE. Furthermore, when evaluated as cathode material in Zn‐NO3− battery, high power density (7.56 mW cm−2) and NH4+ yield (76 µmol h−1 cm−2) are achieved by the metastable phase Cu‐based battery.
Metastable phase Cu is synthesized by a novel O2/Ar plasma oxidation and subsequent electro‐reduction strategy. Due to the unique electronic structure, the metastable phase Cu exhibits superior electrocatalytic nitrate reduction performance to conventional phase Cu for ammonia synthesis. Specifically, the metastable phase Cu can significantly promote the coupling of NO2− with active H atoms, thus improving the performance of NH3 synthesis.
Developing highly efficient, low‐cost electrocatalysts with long‐time stability at high current density working conditions for hydrogen evolution reaction (HER) remains a great challenge for the ...large‐scale commercialization of hydrogen production from water electrolysis. Herein, the Cr‐doped CoP nanorod arrays on carbon cloth (Cr‐CoP‐NR/CC) is reported as high performance HER catalysts with overpotentials of 38 and 209 mV at the HER current densities of 10 and 500 mA cm−2, respectively, outperforming the performance of the commercial Pt/C at high current density. And its HER performance shows almost no loss after 20 h working at 500 mA cm−2. The high performance is attributed to the Cr doping, which optimizes the hydrogen binding energy of CoP and prevents its oxidation. The nanorod array structure helps the escaping of the generated hydrogen gas, which is suitable for working at high current density. The obtained Cr‐CoP‐NR/CC catalyst shows the potential to replace the costly Pt‐based HER catalysts in the water electrolyzer.
Transition metal phosphides are promising catalysts for hydrogen evolution reaction (HER) but still have the gaps to the commercial noble metal catalysts. This study reports a Cr‐doping method to fabricate high‐active and high‐stability Cr‐doped CoP nanorod arrays for HER at high current density, demonstrating that charge transfer and surface Cr species contribute to the performance enhancement.
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