CNT Composite ß-MnO2 with Fiber Cable Shape as Cathode Materials for Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (AZIBs) have developed into one of the most attractive materials for large-scale energy storage owing to their advantages such as high energy density, low cost, and environmental friendliness. Nevertheless, the sluggish diffusion kinetics and inherent impoverished conductivity affect their practical application. Herein, the ß-MnO2 composited with carbon nanotubes (CNT@M) is prepared through a simple hydrothermal approach as a high-performance cathode for AZIBs. The CNT@M electrode exhibits excellent cycling stability, in which the maximum specific discharge capacity is 259 mA h g-1 at 3 A g-1, and there is still 220 mA h g-1 after 2000 cycles. The specific capacity is obviously better than that of ß-MnO2 (32 mA h g-1 after 2000 cycles). The outstanding electrochemical performance of the battery is inseparable from the structural framework of CNT and inherent high conductivity. Furthermore, CNT@M can form a complex conductive network based on CNTs to provide excellent ion diffusion and charge transfer. Therefore, the active material can maintain a long-term cycle and achieve stable capacity retention. This research provides a reasonable solution for the reliable conception of Mn-based electrodes and indicates its potential application in high-performance AZIB cathode materials.

How health risk factors affect inpatient costs among adults with stroke in China: the mediating role of length of stay.

BACKGROUND: As stroke has become the leading cause of death and disability in China, it has induced a heavy disease burden on society, families, and patients. Despite much attention within the literature, the effect of multiple risk factors on length of stay (LOS) and inpatient costs in China is still not fully understood. AIM: To analyse the association between the number of risk factors combined and inpatient costs among adults with stroke and explore the mediating effect of LOS on inpatient costs. METHODS: A retrospective cross-sectional study was conducted among stroke patients in a tertiary hospital in Nantong City from January 2018 to December 2019. Lifestyle factors (smoking status, exercise), personal disease history (overweight, hypertension, dyslipidemia, diabetes mellitus, atrial fibrillation), family history of stroke, and demographic characteristics were interviewed by trained nurses. Inpatient costs and LOS were extracted from electronic medical records. Hierarchical multiple linear regression models and mediation analysis were used to examine the direct and indirect effects of the number of risk factors combined for stroke on inpatient costs. RESULTS: A total of 620 individuals were included, comprising 391 ischaemic stroke patients and 229 haemorrhagic stroke patients, and the mean age was 63.2 years, with 60.32% being male. The overall mean cost for stroke inpatients was 30730.78 CNY ($ 4444.91), and the average length of stay (LOS) was 12.50 days. Mediation analysis indicated that the greater number of risk factors was not only directly related to higher inpatient costs (direct effect = 0.16, 95%CI:[0.11,0.22]), but also indirectly associated with inpatient cost through longer LOS (indirect effect = 0.08, 95% CI: [0.04,0.11]). Furthermore, patients with high risk of stroke had longer LOS than those in low-risk patients, which in turn led to heavier hospitalization expenses. CONCLUSIONS: Both the greater number of risk factors and high-risk rating among stroke patients increased the length of stay and inpatient costs. Preventing and controlling risk behaviors of stroke should be strengthened.

The role of effort-reward imbalance and depressive symptoms in the relationship between long working hours and presenteeism among Chinese village doctors: a moderated mediation model.

BACKGROUND: Long working hours and effort-reward imbalance (ERI) among medical workers may contribute to poor mental health and reduced productivity. However, the potential mechanisms among them are not well understood. This study aimed to explore the role of depressive symptoms and ERI in the relationship between long working hours and presenteeism among village doctors. METHODS: We conducted a cross-sectional study in Jiangsu Province, eastern China. 705 village doctors were assessed for working hours, ERI (the Effort-Reward Imbalance Questionnaire, ERI questionnaire), presenteeism (6-item Stanford Presenteeism Scale, SPS-6 Scale), and depressive symptoms (12-item General Health Questionnaire, GHQ-12). A moderated mediation model was used to test the role of depressive symptoms (M), and ERI (W) in the relationship between long working hours (X) and presenteeism (Y). RESULTS: 45.11% of the village doctors worked more than 55 h per week, and 55.89% were exposed to ERI. The prevalence of depressive symptoms among Chinese village doctors was 40.85%. Long working hours (≥ 55 h per week) were significantly associated with presenteeism behaviors (ß = 2.17, P < 0.001). Mediation analysis demonstrated that depressive symptoms (GHQ score > 3) could partly mediate the relationship between long working hours and presenteeism (indirect effect ß = 0.64, P < 0.001). Moderated mediation further indicated that the interaction of long working hours and ERI was significantly and positively associated with depressive symptoms, which in turn predicted elevated presenteeism behaviors. CONCLUSIONS: Depressive symptoms had a mediating role in the association of long working hours with presenteeism behaviors among Chinese village doctors and ERI augment their negative effects.

Electrostatic Self-Assembly Synthesis of Three-Dimensional Mesoporous Lepidocrocite-Type Layered Sodium Titanate as a Superior Adsorbent for Selective Removal of Cationic Dyes via an Ion-Exchange Mechanism.

Three-dimensional mesoporous lepidocrocite-type layered sodium titanate (LST) was constructed at room temperature by the electrostatic interaction between Ti1-δO24δ- nanosheets and Na+ ions. The results of a systematic X-ray diffraction investigation manifested the transition from the Ti1-δO24δ- nanosheets phase to the titanate/titania phase, which determined a phase diagram as a function of the temperature and NaCl concentration. In addition, scanning electron microscopy, inductively coupled plasma-mass spectrometry, thermogravimetric and differential thermal, N2 adsorption-desorption, Raman spectroscopy, Fourier transform infrared spectroscopy, as well as ζ-potential analyses were utilized for adequate characterization of the LST physical and chemical properties. Furthermore, batch adsorption experiments demonstrated that LST had superior adsorption property and adsorption selectivity toward cationic dyes compared to those of anionic dyes. A multifarious influencing effect on the cationic dye adsorption behavior during the adsorption process was systematically investigated. Moreover, the pseudo-second-order kinetic model felicitously depicted the cationic dye adsorption behavior through an elaborate kinetic study, namely, chemisorption was the main adsorption action. Meanwhile, different adsorption isotherm models were utilized to process the experimental data, uncovering that the adsorption isotherms of cationic dyes on LST were suitable for a Langmuir isothermal model. More importantly, an ion-exchange mechanism was proposed for the cationic dye adsorption on LST, and the ion-exchange reaction occurred with a stoichiometric exchange between 1 mol of Na+ ions in the LST interlayer and 1 mol of MB molecules in the solution. In parallel, the electrochemical impedance spectroscopy and cyclic voltammogram measurements verified that the high ionic conductivity of Na+ ions in the LST interlayer resulted in a superior adsorption property. A two-step acid-base procedure was ultimately adopted to effectively regenerate LST adsorbent. This work provides not only an alternative adsorbent with superior adsorption capacity and adsorption selectivity but also some guiding significance for research on the adsorption mechanism of layered titanates.

Manipulating Molecular Self-Assembly Process at the Solid-Liquid Interface Probed by Scanning Tunneling Microscopy.

The phenomenon of ordered self-assembly on solid substrates is a topic of interest in both fundamental surface science research and its applications in nanotechnology. The regulation and control of two-dimensional (2D) self-assembled supra-molecular structures on surfaces have been realized through applying external stimuli. By utilizing scanning tunneling microscopy (STM), researchers can investigate the detailed phase transition process of self-assembled monolayers (SAMs), providing insight into the interplay between intermolecular weak interactions and substrate-molecule interactions, which govern the formation of molecular self-assembly. This review will discuss the structural transition of self-assembly probed by STM in response to external stimuli and provide state-of-the-art methods such as tip-induced confinement for the alignment of SAM domains and selective chirality. Finally, we discuss the challenges and opportunities in the field of self-assembly and STM.

Hierarchical spheroidal MOF-derived MnO@C as cathode components for high-performance aqueous zinc ion batteries.

Aqueous zinc-ion batteries (AZIBs) have shown great potential as energy storage devices owing to their high energy density, low cost, and low toxicity. Typically, high performance AZIBs incorporate manganese-based cathode materials. Despite their advantages, these cathodes are limited by significant capacity fading and poor rate performance due to the dissolution and disproportionation of manganese. Herein, hierarchical spheroidal MnO@C structures were synthesized from Mn-based metal-organic frameworks, which benefit from a protective carbon layer to prevent manganese dissolution. The spheroidal MnO@C structures were incorporated onto a heterogeneous interface to act as a cathode material for AZIBs, which exhibited excellent cycling stability (160 mAh g-1 after 1000 cycles at 3.0 A g-1), good rate capability (165.9 mAh g-1 at 3.0 A g-1), and appreciable specific capacity (412.4 mAh g-1 at 0.1 A g-1) for AZIBs. Moreover, the Zn2+ storage mechanism in MnO@C was comprehensively investigated using ex-situ XRD and XPS studies. These results demonstrate that hierarchical spheroidal MnO@C is a potential cathode material for high-performing AZIBs.

Proton Self-Doped Polyaniline with High Electrochemical Activity for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries are promising energy storage devices due to their low cost, good ionic conductivity, and high safety. Conductive polyaniline is a promising cathode because of its redox activity, but because the neutral electrolyte protonates only weakly, it displays limited electrochemical activity. A polyaniline cathode is developed with proton self-doping from manganese metal-organic frameworks (Mn-MOFs) that alleviates the deprotonation and electrochemical activity concerns arising during the charge/discharge process. The MOFs carboxyl group provides protons to prevent deprotonation and allows the polyaniline to reach a high zinc storage redox activity. The proton self-doped polyaniline cathode has a superior specific capacity (273 mAh g-1 at 0.5 A g-1 ), a high rate property (154 mAh g-1 at 20 A g-1 ), and excellent cyclability retention (87% over 4000 cycles at 15 A g-1 ). This research provides fresh insight into the development of innovative polymers as cathode materials for high-performance AZIBs.

Impact of long working hours on depressive symptoms among COVID-19 frontline medical staff: The mediation of job burnout and the moderation of family and organizational support.

Background: During the COVID-19 pandemic, the frontline medical staff faced more workload and heavier physical and mental stress, which increased their job burnout and negative emotions. However, little is known about the potential factors mediating and moderating these relations. This study investigates the association between long working hours and depressive symptoms among frontline medical staff in China, and explores the potential mediating effect of job burnout, and moderating effect of family and organizational support on these associations. Methods: Data of 992 frontline medical staff who participated in the prevention and control of COVID-19 was obtained from the online survey conducted in November to December 2021 in China. Depressive symptoms were evaluated using the Patient Health Questionaire-9 (PHQ-9). Moderated mediating model was employed to understand the relationship between long working hours (X), depressive symptoms (Y) mediated through job burnout (M), moderated by family support (W1) and organizational support (W2), while controlling all possible covariates. Results: 56.96% of participants worked more than 8 h per day. 49.8% of them had depressive symptoms (PHQ-9 ≥ 5) and 65.8% experienced job-related burnout. Long working hours was positively associated with depressive symptoms score (ß = 0.26, 95% CI:0.13 ~ 0.40). Mediation analyses revealed that job burnout significantly mediated this relationship (indirect effect = 0.17, 95% CI: 0.08 ~ 0.26). Moderated mediation further indicated that both two interactions of social support (family support W1, organizational support W2) and job burnout were negatively related to depressive symptoms among frontline medical staff, indicating that higher social support being less job burnout with lower depressive symptoms. Conclusion: Longer working hours and higher job burnout may contribute to worse mental health among frontline medical staff. Social support could buffer the detrimental effects by reducing their job burnout. Contribution: The main contribution of this study was to estimate the negative effect of long working hours on depressive symptoms among frontline medical staff and explore the potential mediating role of job burnout and moderating role of social support on these associations.

[Ecosystem structure and function of Sanmen Bay based on Ecopath model.] / 基于Ecopath模型的三门湾生态系统结构与功能.

Ecosystem structure determines material circulation, energy flow, and system function. Based on field investigation data in the Sanmen Bay, East China Sea from 2017 to 2018, ecological channel model was constructed by Ecopath, describing energy flow routes and functional characteristics of the Sanmen Bay ecosystem. Results showed that grazing food chain was the main energy circulation channel, and the trophic level of each functional group ranged from 1 to 3.80. Energy flow of the system was mainly concentrated in the first five levels, with an average energy conversion efficiency of 13.0%. Energy conversion efficiency was 12.8% and 14.5% from primary producers and debris, respectively. Connectance index (CI) and system omnivory index (SOI) were 0.40 and 0.24 respectively. Finn's cycling index (FIC) was 0.40, and Finn's mean path length (MPL) was 2.06. The ratio of total primary productivity to total respiration was 13.59. In conclusion, Sanmen Bay ecosystem was immature in material circulation and energy flow. This work is helpful to understand the structural and functional traits of coastal ecosystems in China.

Can top-down effects of planktivorous fish removal be used to mitigate cyanobacterial blooms in large subtropical highland lakes?

Removal of planktivorous fish is used extensively in northern temperate lakes to reduce phytoplankton abundance via enhanced zooplankton grazing. However, whether this method would work also in large subtropical highland lakes to alleviate cyanobacterial blooms is unknown. We conducted a one-year pilot in situ experiment where we removed a substantial biomass of fish in a fenced-in area, followed by a 3-year whole-lake experiment where the dominant fish species (Japanese smelt) was removed in Lake Erhai in southwest China. The fencing experiments showed that between July and November, when the biomass of the removed stock reached 4 g/m2, the zooplankton biomass inside the fence increased significantly compared to a control fence. In the full-lake experiment, we found that sustained removal of Japanese smelt led to an increase in the biomass of cladocerans (Daphnia spp. but especially of Bosmina spp.) and a significant decrease in the biomass of Cyanobacteria and Chlorophyta. Additionally, a marked increase in the ratio of zooplankton to phytoplankton biomass, as well as an increase in the body size of cladocerans, emphasising the importance of enhanced top-down control for mitigating cyanobacterial blooms following extensive fish removal. Our results reveal that removal of small fish (here Japanese smelt) can lead to a reduction of the phytoplankton and cyanobacteria biomass through a trophic cascade in highland deep subtropical lakes. Thus fish removal may be a feasible additional restoration tool to external nutrient loading reduction in such lakes.

Coordinately Unsaturated Manganese-Based Metal-Organic Frameworks as a High-Performance Cathode for Aqueous Zinc-Ion Batteries.

The slow Zn2+ intercalation/deintercalation kinetics in cathodes severely limits the electrochemical performance of aqueous zinc-ion batteries (ZIBs). Herein, we demonstrate a new kind of coordinately unsaturated manganese-based metal-organic framework (MOF) as an advanced cathode for ZIBs. Coordination unsaturation of Mn is performed with oxygen atoms of two adjacent -COO-. Its proper unsaturated coordination degree guarantees the high-efficiency Zn2+ transport and electron exchange, thereby ensuring high intrinsic activity and fast electrochemical reaction kinetics during repeated charging/discharging processes. Consequently, this MOF-based electrode possesses a high capacity of 138 mAh g-1 at 100 mA g-1 and a long life span (93.5% capacity retention after 1000 cycles at 3000 mA g-1) due to the above advantages. Such distinct Zn2+ ion storage performance surpasses those of most of the recently reported MOF cathodes. This concept of adjusting the coordination degree to tune the energy storage capability provides new avenues for exploring high-performance MOF cathodes in aqueous ZIBs.

Regulating the Interlayer Spacing of Vanadium Oxide by In Situ Polyaniline Intercalation Enables an Improved Aqueous Zinc-Ion Storage Performance.

Vanadium pentoxide (V2O5) possesses great potential for application as cathode materials for aqueous zinc-ion batteries due to abundant valences of vanadium. Unfortunately, the inferior electronic conductivity and confined interlayer spacing of pristine V2O5 are not able to support fast Zn2+ diffusion kinetics, leading to significant capacity degradation, the dissolution of active species, and unsatisfactory cycling life. Herein, Zn2+ (de)intercalation kinetics is improved by the design of in situ polyaniline (PANI)-intercalated V2O5. The intercalated PANI can not only improve the conductivity and structural stability of V2O5 but also efficiently expand its interlayer spacing (1.41 nm), offering more channels for facile Zn2+ diffusion. Benefiting from these virtues, a high specific capacity of 356 mA h g-1 at 0.1 A g-1 is achieved for the PANI-intercalated V2O5 (PVO) cathode as well as a superior cycling performance (96.3% capacity retention after 1000 cycles at 5 A g-1) in an aqueous electrolyte. Furthermore, the Zn2+ storage in PVO is mainly dominated by the capacitive contribution. This work suggests that intercalating PANI in V2O5 may aid in the future development of advanced cathodes for other multivalent metal ion batteries.

Synthesis and Electrochemical Properties of LiNi0.5Mn1.5O4 for Li-Ion Batteries by the Metal-Organic Framework Method.

A LiNi0.5Mn1.5O4 cathode material with high surface orientation was prepared via a complexing reaction coupled with the elevated-temperature solid-state method. First, a bimetal-organic framework containing Ni2+ and Mn2+ ions was synthesized via a self-assembly route using pyromellitic acid (PMA) as a dispersant and complexing agent. This step was followed by calcination with lithium acetate using PMA as a structure-directing agent. The resulting LiNi0.5Mn1.5O4 (M-LNMO) cathode material was investigated using X-ray diffraction, transmission and scanning electron microscopies, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and charge/discharge tests. For comparison, LiNi0.5Mn1.5O4 samples were prepared by coprecipitation and the solid-phase method under the same conditions. M-LNMO was highly crystalline with low impurity, uniform grain size, and a preferred orientation in the (111) and (110) planes. Owing to these advantages, the M-LNMO cathode material exhibited overwhelmingly high cyclic stability and rate capability and M-LNMO delivered a capacity of 145 mAh g-1 at a discharge rate of 0.1C and a discharge capacity retention of 86.6% at 5C after 1000 cycles. Even at an extremely high discharge rate (10C), the specific capacity was 112.7 mAh g-1, and 78.7% of its initial capacity was retained over 500 cycles. The superior electrochemical performance, particularly during a low-rate operation, was conferred by improved crystallinity and the crystal orientation of the particles.

Physicochemical Process, Crustacean, and Microcystis Biomass Changes In Situ Enclosure after Introduction of Silver Carp at Meiliang Bay, Lake Taihu.

In order to control cyanobacteria blooms with silver carp in Lake Taihu, an in situ experiment was carried out by stocking silver carp at a biomass of 35, 70, and 150 g m-3 and no carp control in waterproof enclosures. Physicochemical water parameters and biomass of plankton were measured in enclosures to evaluate the suitable stocking density of silver carp for relieving internal nutrients and constraining cyanobacteria growth in Lake Taihu. It is found that the 35 g m-3 silver carp group and 70 g m-3 silver carp group presented lower total phosphorus, lower chlorophyll-a, and higher water transparency. Increased nitrogen to phosphorus ratio, which indicated the result of algae decline in fish presence enclosures, was attributed to decline of phosphorus. Phosphorus decline also exerted limitation on reestablish of cyanobacteria bloom. Crustacean zooplankton biomass and Microcystis biomass decreased significantly in fish presence enclosures. Silver carp could be more effective to regulate algae bloom in enclosures with dense cyanobacteria. Therefore, nonclassic manipulation is supposed to be appropriate method to get rid of cyanobacteria blooms in Lake Taihu by stocking 35 to 70 g m-3 silver carp in application.

A Novel and Facile One-Pot Solvothermal Synthesis of PEDOT-PSS/Ni-Mn-Co-O Hybrid as an Advanced Supercapacitor Electrode Material.

In this work, a novel and facile one-pot method has been developed for the synthesis of a hybrid consisting of Ni-Mn-Co ternary oxide and poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT-PSS/NMCO) with a hierarchical three-dimensional net structure via a solvothermal-coprecipitation coupled with oxidative polymerization route. Apart from the achievement of polymerization, coprecipitation, and solvothermal in one pot, the hydroxyl (OH(-)) ions generated from the oxidative polymerization of organic monomer by neutral KMnO4 solution were skillfully employed as precipitants for metal ions. As compared with the PEDOT-PSS/Ni-Mn binary oxide, PEDOT-PSS/Co-Mn binary oxide, and PEDOT-PSS/MnO2, PEDOT-PSS1.5/NMCO exhibits overwhelmingly superior supercapacitive performance, more specifically, a high specific capacitance of 1234.5 F g(-1) at a current density of 1 A g(-1), a good capacitance retention of 83.7% at a high current density of 5 A g(-1) after 1000 cycles, an energy density of 51.9 W h kg(-1) at a power density of 275 W kg(-1), and an energy density of 21.4 W h kg(-1) at an extremely elevated power density of 5500 W kg(-1). Noticeably, the energy density and power density of PEDOT-PSS/NMCO are by far higher than those of the existing analogues recently reported. The exceptional performance of PEDOT-PSS/NMCO benefits from its unique mesoporous architecture, which could provide a larger reaction surface area, faster ion and electron transfer ability, and good structural stability. The desirable integrated performance enables the multicomponent composite to be a promising electrode material for energy storage applications.