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1.
BMJ Open ; 14(10): e082430, 2024 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-39461863

RESUMEN

OBJECTIVES: This study aimed to examine patient delay, diagnosis delay and treatment performance among patients with tuberculosis (TB) in Shanghai, China in 2018-2020 focusing on disparities between migrant and local patients with TB. DESIGN: Mixed-method study. SETTING AND PARTICIPANTS: Quantitative data were collected from the TB information management system in Shanghai; 17 533 bacteriologically confirmed and clinically diagnosed patients with pulmonary TB registered in 2018-2020 were included. Qualitative interviews were conducted with TB administrators (n=3) and community healthcare providers (two groups, n=10 in total) from Shanghai. MAIN OUTCOME MEASURES: Patient delay, diagnosis delay and treatment completion were examined by resident type using descriptive analysis and logistic regressions. Qualitative interviews were conducted to understand factors associated with the disparities. RESULTS: From 2018 to 2020, migrant patients with TB accounted for 44.40% of total cases. There was no significant difference in patient delay between migrant and local patients (18.47 days on average). 22.12% of migrants and 16.52% of locals experienced diagnosis delays exceeding 14 days, respectively. After adjusting for all variables, migrant patients (OR 1.30, 95% CI 1.18 to 1.44) and initial care seeking at general hospitals (OR 3.76, 95% CI 3.45 to 4.09) were associated with a higher probability of diagnosis delay. 93.9% of migrant patients and 89.4% of the local patients had a successful TB treatment without statistically significant difference after adjusting for all variables. Qualitative interviews revealed a standard approach to managing patients with TB in Shanghai no matter their resident type. Young migrant patients who were able to maintain their jobs in Shanghai often had better treatment adherence. Despite patients' COVID-19 fear and limited care access in 2020, TB treatment minimally affected for both due to community-based case management. CONCLUSIONS: Migrant patients were more likely to experience diagnosis delay. It should improve awareness and knowledge of TB among healthcare professionals at general hospitals to mitigate the risk of diagnosis delay.


Asunto(s)
Diagnóstico Tardío , Migrantes , Tuberculosis Pulmonar , Humanos , China/epidemiología , Femenino , Diagnóstico Tardío/estadística & datos numéricos , Masculino , Migrantes/estadística & datos numéricos , Adulto , Persona de Mediana Edad , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/terapia , Adulto Joven , Resultado del Tratamiento , Adolescente , Anciano , Tiempo de Tratamiento/estadística & datos numéricos , Investigación Cualitativa
2.
J Colloid Interface Sci ; 673: 444-452, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38878378

RESUMEN

Electrocatalytic water splitting (EWS) for hydrogen production is considered an ideal strategy for utilizing renewable energy, reducing fossil fuel consumption, and addressing environmental pollution issues. Traditional noble metal electrocatalysts have excellent performance, but their cost is high. Developing efficient, stable, and relatively inexpensive dual functional electrocatalysts is crucial for promoting large-scale EWS hydrogen production processes. Herein, a simple one-step electrodeposition method was used to grow nickel-iron phosphorus-sulfides (NiFePS) on the surface of hydrophilic treated carbon cloth (CC). The resultant NiFePS/CC with a phosphorus to sulfur ratio of 1:4 exhibited the best electrocatalytic performance, requiring only -91 mV and 216 mV overpotentials to generate the current densities of 10 mA·cm-2 in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. When it was used as a bifunctional electrocatalyst to overall water splitting (OWS), a voltage of 1.536 V can generate a current density of 10 mA·cm-2. The excellent electrocatalytic performance can be ascribed to two factors: 1) the CC with excellent conductivity serves as a growth substrate, reducing the impedance of charge transfer from the electrode to the electrolyte and accelerating the electron transfer rate; 2) The large number of ultra-thin nanosheets formed on the surface of the catalyst increase the electrochemical specific surface area, expose more reaction sites, and thus improve the electrocatalytic reaction performance. This work provides a new approach for designing efficient non-noble metal electrocatalysts for water splitting.

3.
Small ; 20(37): e2402537, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38711307

RESUMEN

Cu-based catalysts are the most intensively studied in the field of electrocatalytic CO2 reduction reaction (CO2RR), demonstrating the capacity to yield diverse C1 and C2+ products albeit with unsatisfactory selectivity. Manipulation of the oxidation state of Cu sites during CO2RR process proves advantageous in modulating the selectivity of productions, but poses a formidable challenge. Here, an oxygen spillover strategy is proposed to enhance the oxidation state of Cu during CO2RR by incorporating the oxygen donor Sb2O4. The Cu-Sb bimetallic oxide catalyst attains a remarkable CO2-to-CO selectivity approaching unity, in stark contrast to the diverse product distribution observed with bare CuO. The exceptional Faradaic efficiency of CO can be maintained across a wide range of potential windows of ≈700 mV in 1 m KOH, and remains independent of the Cu/Sb ratio (ranging from 0.1:1 to 10:1). Correlative calculations and experimental results reveal that oxygen spillover from Sb2O4 to Cu sites maintains the relatively high valence state of Cu during CO2RR, which diminishes the binding strength of *CO, thereby achieving heightened selectivity in CO production. These findings propose the role of oxygen spillover in CO2RR over Cu-based catalysts, and shed light on the rational design of highly selective CO2 reduction catalysts.

4.
J Hazard Mater ; 470: 134221, 2024 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-38615651

RESUMEN

Constructed wetlands (CWs) are a promising approach for treating acid mine drainage (AMD). However, the extreme acidity and high loads of heavy metals in AMD can easily lead to the collapse of CWs without proper pre-treatment. Therefore, it is considered essential to maintain efficient and stable performance for AMD treatment in CWs. In this study, pre-prepared attapulgite-soda residue (ASR) composites were used to improve the substrate of CWs. Compared with CWs filled with gravel (CWs-G), the removal efficiencies of sulfate and Fe, Mn, Cu, Zn Cd and Pb in CWs filled with ASR composites (CWs-ASR) were increased by 30% and 10-70%, respectively. These metals were mainly retained in the substrate in stable forms, such as carbonate-, Fe/Mn (oxide)hydroxide-, and sulfide-bound forms. Additionally, higher levels of photosynthetic pigments and antioxidant enzyme activities in plants, along with a richer microbial community, were observed in CWs-ASR than in CWs-G. The application of ASR composites alleviated the adverse effects of AMD stresses on wetland plants and microorganisms. In return, the increased bacteria abundance, particularly SRB genera (e.g., Thermodesulfovibrionia and Desulfobacca), promoted the formation of metal sulfides, enabling the saturated ASR adsorbed with metals to regenerate and continuously capture heavy metals. The synergistic adsorption of ASR composites and microbial sulfate reduction maintained the stable and efficient operation of CWs. This study contributes to the resource utilization of industrial alkaline by-products and promotes the breakthrough of new techniques for low-cost and passive treatment systems such as CWs.


Asunto(s)
Compuestos de Magnesio , Metales Pesados , Minería , Compuestos de Silicona , Sulfatos , Contaminantes Químicos del Agua , Humedales , Sulfatos/química , Metales Pesados/química , Adsorción , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/metabolismo , Compuestos de Silicona/química , Compuestos de Magnesio/química , Ácidos/química , Oxidación-Reducción , Biodegradación Ambiental , Concentración de Iones de Hidrógeno
5.
ACS Appl Mater Interfaces ; 16(10): 12398-12406, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38412364

RESUMEN

The metal-nitrogen-carbon (M-N-C)-based catalysts are promising to replace PGM (platinum group metal) to accelerate oxygen reduction reaction due to their excellent electrocatalytic performance. However, the inferior intrinsic activity and poor active site density confining further improvement in their performance. Modulating the electronic structure and reasonably designing the pore structure are widely acknowledged effective strategies to boost the activity of the M-N-C catalysts. However, it is a great challenge to form abundant pores to regulate the electronic structure via the facile method. Herein, a hierarchical, porous dual-atom catalyst FeNi-NPC-1000 has been architectured by the Na2CO3 template method and bimetallic doping modification strategy. Benefitting from the optimized pore and electronic structure, the as-prepared FeNi-NPC-1000 possesses a high specific surface area (1412.8 m2 g-1) and improved ORR activity (E1/2 = 0.877 V vs RHE), which is superior to that of Pt/C (E1/2 = 0.867 V vs RHE). With the evidence of AC-STEM, XAS, and DFT, the FeNi-N8-C moiety is proven to be the key active site to realize high-efficiency ORR catalysis. When assembled it as an air cathode of ZABs, FeNi-NPC-1000 displays superior discharge performance (Pmax = 367.1 mW cm-2) and a stable battery long-life. This article will provide a new strategy for designing dual-metal atomic catalysts applied in metal-air batteries.

6.
Sci Rep ; 14(1): 5007, 2024 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-38424313

RESUMEN

It is of interest to develop wide-temperature domain damped hydrophobic materials. In this paper, we designed incorporating bio-based phenolic resin into the IIR matrix and introducing dibenzyl fork acetone (DBA) into the main chain structure with sodium hydroxide activation to construct three-dimensional network. In this paper, we designed incorporating bio-based phenolic resin into the IIR matrix and introducing dibenzyl fork acetone (DBA) into the main chain structure with sodium hydroxide activation to construct three-dimensional network. The added bio-based phenolic resin has reticulated structure blended with butyl rubber, combined with sodium hydride activation-modified IIR. The results show that sodium hydride activated modification of DBA is introduced into the main chain structure of IIR by infrared and 1H NMR analysis. The material hydrophobic is realized by the introduction of DBA with static water contact angle of 103.5°. The addition of 10phr lignin-based phenolic resin (LPF) is compatible with IIR, and the torque can reach 7.0 N-m. The tensile elongation of the modified butyl rubber composite can reach 2400% with tensile strength up to 11.43 MPa, while the damping factor can reach 0.37 even at 70 °C. The thermal stability of the composites is enhanced with mass retention rate of 28%. The bio-based PF/NaH activation-modified butyl rubber damping material has potential applications in damping hydrophobicity with wide temperature range.

7.
Environ Pollut ; 344: 123337, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38266698

RESUMEN

The in situ biosequestration of Cr(VI) in groundwater with molasses as the carbon source was studied based on column experiments and model simulation in this study. Compared with biological reduction, molasses-based chemical reduction did not cause significant Cr(VI) removal at molasses concentration as high as 1.14 g L-1. The molasses at a concentration as low as 0.57 g L-1 could support biofilm-based Cr(VI) sequestration under flow conditions and showed better sequestration performances than D-glucose and emulsified vegetable oil (8 g L-1). The existence of molasses (1.14 g L-1) decreased the pH of the effluent from 7.5 to 6.3 and the oxidation-reduction potential from 275 mV to 220 mV in the groundwater, which was responsible for reduction and thus the sequestration of Cr(VI). Advection-dispersion-reaction model well described the process of the Cr(VI) transport with biosequestration in the column (R2 ≥ 0.96). Owing to the Cr(VI) toxicity to the biofilms, the removal ratio decreased by 24% with a rise of Cr(VI) concentration from 8.6 to 43 mg L-1. The prolongation of hydraulic retention time could promote the performance of Cr(VI) biosequestration. The chemical form of Cr deposited as the product of bio-reduction was confirmed as Cr(OH)3·H2O and other complexes of Cr(III). Our work demonstrated the efficacy of molasses for in situ sequestration of Cr(VI) under the dynamic flow condition and provide some useful information for Cr-contaminated groundwater remediation.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Melaza , Agua Subterránea/química , Cromo/química , Carbono
8.
ACS Appl Mater Interfaces ; 15(51): 59432-59443, 2023 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-38108306

RESUMEN

Acidic oxygen evolution reaction (OER) remains a significant challenge due to the low activity and/or poor stability of the catalysts, even with state-of-the-art catalysts such as IrO2 and RuO2. Herein, we propose a strategy to enhance both the catalytic activity and stability of IrRu oxides for acidic OER by doping non-noble metal W. The W-doped IrRu3Ox (W-IrRu3Ox) undergoes a process of W leaching and reconstruction during the OER, leading to a more uniform distribution of elements, while the electronegative nature of W influences the electronic structures of Ir and Ru in W-IrRu3Ox. The dual role of W in promoting the formation of active site Ir5+ and inhibiting the concentration of soluble Ru>4+ ions results in a synergistic enhancement of both the activity and stability of acidic OER. Remarkably, W-IrRu3Ox exhibits outstanding catalytic activity for the OER in 0.5 M H2SO4, with a high stability of more than 500 h. This work presents a novel and feasible strategy for the development of efficient and stable catalysts for acid OER, shedding light on the design of advanced electrocatalysts for energy conversion and storage applications.

9.
Int Breastfeed J ; 18(1): 40, 2023 08 11.
Artículo en Inglés | MEDLINE | ID: mdl-37568207

RESUMEN

BACKGROUND: The World Health Organization and the government of China have made many efforts to improve breastfeeding practices. The evidence of breastfeeding practices over the past decade in China is limited. The current study aimed to describe the current prevalence, variation trends, and determinants of breastfeeding practices in China using data from the National Household Health Service Surveys (NHHSS) in 2013 and 2018. METHODS: Women who had at least one live birth in the five years from the 2013 NHHSS numbered 10,544, and 12,766 women from the 2018 NHHSS were included in the current study. The rates of breastfeeding, early initiation of breastfeeding within the first hour after birth, exclusive breastfeeding for at least six months since birth, and continued breastfeeding accompanied by adequate complementary feeding for over two years were measured. Logistic regressions were performed to study the associations between breastfeeding practices and maternal-based, healthcare-based, and infant-based characteristics. RESULTS: In the 2018 survey, the rates of practiced any breastfeeding, early initiation of breastfeeding within the first hour after birth, exclusive breastfeeding for at least six months, and continued breastfeeding for over two years were 91.50%, 28.16%, 47.90%, and 4.78%, respectively, showing significant improvements compared to the 2013 survey period. Women who received high education, were from a household with high incomes, had more than one child, and had more antenatal and postnatal visits, were more likely to practice breastfeeding and initiate it within the first hour, but they were less likely to breastfeed the infants for two years. Births by caesarean section and low birthweight were associated with worse breastfeeding practices. CONCLUSIONS: The rates of practicing breastfeeding and exclusive breastfeeding for six months or more in China improved over the past decades, suggesting improved awareness and knowledge of breastfeeding among women. However, individual and social factors may impact practices of early initiation and continued breastfeeding. Strengthening breastfeeding support from family, community, and health professionals (e.g., family member engagement, friendly work environment, and professional consultation, etc.) during the postpartum and infant period may improve women's confidence in breastfeeding practices.


Asunto(s)
Lactancia Materna , Servicios de Salud Materna , Femenino , Humanos , Lactante , Embarazo , Cesárea , China/epidemiología , Estudios Transversales , Prevalencia
10.
Adv Sci (Weinh) ; 10(28): e2303726, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37530207

RESUMEN

The recognition of the surface reconstruction of the catalysts during electrochemical CO2 reduction (CO2RR) is essential for exploring and comprehending active sites. Although the superior performance of Cu-Zn bimetallic sites toward multicarbon C2+ products has been established, the dynamic surface reconstruction has not been fully understood. Herein, Zn-doped Cu2 O nano-octahedrons are used to investigate the effect of the dynamic stability by the leaching and redeposition on CO2RR. Correlative characterizations confirm the Zn leaching from Zn-doped Cu2 O, which is redeposited at the surface of the catalysts, leading to dynamic stability and abundant Cu-Zn bimetallic sites at the surface. The reconstructed Zn-doped Cu2 O catalysts achieve a high Faradaic efficiency (FE) of C2+ products (77% at -1.1 V versus reversible hydrogen electrode (RHE)). Additionally, similar dynamic stability is also discovered in Al-doped Cu2 O for CO2RR, proving its universality in amphoteric metal-doped catalysts. Mechanism analyses reveal that the OHC-CHO pathway can be the C-C coupling processes on bare Cu2 O and Zn-doped Cu2 O, and the introduction of Zn to Cu can efficiently lower the energy barrier for CO2RR to C2 H4 . This research provides profound insight into unraveling surface dynamic reconstruction of amphoteric metal-containing electrocatalysts and can guide rational design of the high-performance electrocatalysts for CO2RR.

11.
Curr Oncol ; 30(8): 7654-7671, 2023 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-37623036

RESUMEN

This systematic review examined cancer care costs, the financial burden for patients, and their economic coping strategies in mainland China. We included 38 quantitative studies that reported out-of-pocket payment for cancer care and patients' coping strategies in English or Chinese (PROSPERO: CRD42021273989). We searched PubMed, Embase, Ovid, Web of Science, Cochrane, CNKI, and Wanfang Data from 1 January 2009 to 10 August 2022. We referred to the standards for reporting observational studies to assess the methodological quality and transparent reporting of the included studies and reported the costs narratively. Annual mean medical costs (including inpatient and outpatient costs and fees for self-purchasing drugs) ranged from USD 7421 to USD 10,297 per patient. One study investigated medical costs for 5 years and indicated that inpatient costs accounted for 51.6% of the total medical costs, followed by self-purchasing drugs (43.9%). Annual medical costs as a percentage of annual household income ranged from 36.0% to 63.1% with a metaproportion of 51.0%. The common coping strategies included borrowing money and reduction of household expenses and expenses from basic health services. Costs of inpatient care and self-purchasing drugs are major drivers of medical costs for cancer care, and many affected households shoulder a very heavy financial burden.


Asunto(s)
Estrés Financiero , Neoplasias , Humanos , Neoplasias/terapia , China , Pacientes Internos , Adaptación Psicológica
12.
J Med Chem ; 66(17): 12536-12543, 2023 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-37608596

RESUMEN

In this study, we have investigated the potential of two classes of thioglucoside analogues of gliflozins as antidiabetic drugs, one with substitutions of S-atoms in meta-positions (similar to C-glucoside SGLT2 inhibitors, TAGs A, B, and C) and the other with substitutions of S-atoms in ortho-positions (similar to O-glucoside SGLT2 inhibitors, TAGs D, E, F, and G). These TAGs were confirmed to show good stability against ß-glucosidase and to have no acute toxicity to cultured cells. Most importantly, TAGs D, E, F, and G all showed high inhibitory activity against SGLT2 (IC50: 2.0-5.9 nM) and thus have great potential to be developed as new gliflozin drugs. Compared with the synthesis of C-glucoside gliflozins, the synthesis of TAGs is simple, efficient, and associated with low costs, high yields, and very mild reaction conditions.


Asunto(s)
Inhibidores del Cotransportador de Sodio-Glucosa 2 , Inhibidores del Cotransportador de Sodio-Glucosa 2/farmacología , Hipoglucemiantes/farmacología , Glucósidos/farmacología , Tioglucósidos
13.
Sci Total Environ ; 903: 166601, 2023 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-37634714

RESUMEN

Acid mine drainage (AMD) rich in arsenic (As) and antimony (Sb) is considered as a significant environmental challenge internationally. However, simultaneous removal of As and Sb from AMD is still inadequately studied. In this study, a highly effective and simple approach was proposed for mitigating As and Sb-rich AMD, which involves in-situ formation of layered double hydroxides (LDHs). Following the treatment, the residual concentrations of iron (Fe), magnesium (Mg), sulfate, As and Sb in field AMD were decreased from their initial concentrations of 1690, 1524, 2055, 7.8 and 10.6 mg L-1, respectively, to 1.3, 12.4, 623, 0.006 and 0.004 mg L-1, respectively. Chemical formula of the resulting As and Sb-loaded LDHs can be identified as Mg4.226Fe2.024OH2SO4AsSb0.006∙mH2O. The dissolution rates of metal(loid)s in As and Sb-loaded LDH were lower than 1% under strongly acidic and alkaline environments. In presence of the mixed adsorbates, the As immobilization capacity by LDHs was significantly decreased, with an apparent intervention from Sb. However, As did not have a significant effect on the immobilization of Sb by LDH. As was immobilized by LDHs through anion exchange and complexation with -OH groups, while Sb was captured by anion exchange and complexation with [Formula: see text] . Density functional theory (DFT) calculations further proved the above conclusions. This novel approach is effective and can be applied for in-situ AMD treatment from abandoned mines.

14.
Small ; 19(37): e2206477, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37147778

RESUMEN

Oxygen electrocatalysis has aroused considerable interest over the past years because of the new energy technologies boom in hydrogen energy and metal-air battery. However, due to the sluggish kinetic of the four-electron transfer process in oxygen reduction reaction and oxygen evolution reaction, the electro-catalysts are urgently needed to accelerate the oxygen electrocatalysis. Benefit from the high atom utilization efficiency, unprecedentedly high catalytic activity, and selectivity, single-atom catalysts (SACs) are considered the most promising candidate to replace the traditional Pt-group-metal catalysts. Compared with SACs, the dual-atom catalysts (DACs) are attracting more attraction including higher metal loading, more versatile active sites, and excellent catalytic activity. Therefore, it is essential to explore the new universal methods approaching to the preparation, characterization, and to elucidate the catalytic mechanisms of the DACs. In this review, several general synthetic strategies and structural characterization methods of DACs are introduced and the involved oxygen catalytic mechanisms are discussed. Moreover, the state-of-the-art electrocatalytic applications including fuel cells, metal-air batteries, and water splitting have been sorted out at present. The authors hope this review has given some insights and inspiration to the researches about DACs in electro-catalysis.

15.
J Multidiscip Healthc ; 16: 997-1010, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37056979

RESUMEN

Background: In China, physicians have long faced long working hours, high stress levels, and tensions between physicians and patients, which can lead to negative behaviors. Understanding physicians' expectations and requirements of the hospital and increasing satisfaction with their psychological contract can help improve physician motivation and stabilize the hospital team. Aim: The study aims to analyze the relationship between physicians' psychological contract violations and different behavioral choices, encourage hospitals to conclude a balanced psychological contract with physicians, and provide governance and intervention strategies for hospital human resource management. Methods: Stratified cluster sampling was used to select 321 physicians from four public hospitals in Beijing for questionnaire surveys. Descriptive statistical analysis, t-test, ANOVA, correlation analysis, and regression models were performed using Stata 15.0 and SPSS 26.0 to analyze the relationship between psychological contract violations, physicians' EVLN behaviors and organizational justice. Results: Psychological contract violation had a positive effect on exit behavior and neglect behavior, and a negative effect on voice behavior and loyalty behavior. Organizational justice plays a mediating role between psychological contract violation and physicians' exit, voice and loyalty behaviors. Conclusion: Psychological contract violation can drive negative behavior among physicians, and organizational justice can play a mediating role in this. Public hospitals should establish a healthy psychological contract with physicians and place a premium on organizational justice to promote constructive behaviors and prevent destructive behaviors. This study constructs a more complete theoretical framework to explain physicians' behavior, and further dynamic tracking investigations are necessary because the evolution of physicians' behavior is a dynamic and long-term process.

16.
Small ; 19(8): e2206478, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36504185

RESUMEN

Platinum group metal (PGM)-free M-N-C catalysts have exhibited dramatic electrocatalytic performance and are considered the most promising candidate of the Pt catalysts in oxygen reduction reaction (ORR). However, the electrocatalytic performance of the M-N-C catalysts is still limited by their inferior intrinsic activity and finite active site density. Regulating the coordination environment and increasing the pore structure of the catalyst is an effective strategy to enhance the electrocatalytic performance of the M-N-C catalysts. In this work, the coordination environment and pore structure exquisitely regulated Fe-N-C catalyst exhibit excellent ORR activity and durability. With the enhanced intrinsic activity and increased active site density, the optimized Fe-N/S-C catalyst shows impressive ORR activity (E1/2  = 0.904 V vs reversible hydrogen electrode (RHE)) and superior long-term durability in an alkaline medium. As the advanced physical characterization and theoretical chemistry methods illustrate, the S-modified Fe-Nx (Fe-N3 /S-C) moiety is confirmed as the improved active center for ORR, and the increased active site density further improved ORR efficiency. Based on the Fe-N/S-C cathode, a Zn-air battery is fabricated and shows superior power density (315.4 mW cm-2 ) and long-term discharge stability at 20 mA cm-2 . This work would open a new perspective to design atomically dispersed iron-metal site catalysts for advanced electro-catalysis.

17.
Sci Total Environ ; 843: 157120, 2022 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-35787898

RESUMEN

Implementing an economical and effective measure for treating acid mine drainage (AMD) from abandoned mines using low-cost restoration reagents present a significant challenge. In this study, natural attapulgite (AT) and soda residue (SR) composite particles (AT-SR) were firstly prepared and utilized in AMD treatment. The efficiencies and mechanisms of AT-SR composites for regulating acidity and removing metals in AMD, the critical factors influencing the treatment efficiencies, and the regeneration performance and environmental risk were investigated. It is illustrated that AT and SR quality ratio of 5:5, dosage of 0.5 g L-1, particle size < 1.5 mm, concentrations of 150 mg L-1 for Fe, 75 mg L-1 for Mn and 100 mg L-1 for Cu, Zn, Cd and Pb, and adsorption time of 120 min were the optimized conditions. The maximum adsorption capacities of Fe, Mn, Cu, Zn, Cd and Pb under single metal scenarios were 51.61, 22.30, 37.05, 40.21, 37.39 and 49.53 mg g-1, respectively. Under the mixed metal scenarios, competitive adsorption was predominated with the rate constants in the reducing order of 3.169 for Fe > 0.841 for Cu > 0.657 for Pb > 0.083 for Zn > 0.024 for Cd > 0.006 for Mn. The experimental data was fitted well with the pseudo-second-order and the Freundlich isotherm models. AT-SR is an outstanding neutralizer for AMD due to its richness in calcium and magnesium oxides and the spent AT-SR composites could be easily regenerated while maintaining high metal removal efficiencies under the subsequent usages. It is determined under the aqua regia digestion and Toxicity Characteristic Leaching Procedure (TCLP) tests that AT-SR can be used safely without posing environmental risks, thus promoting the resource recovery and utilization of soda residue and providing a green and effective method for treating AMD.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Ácidos , Cadmio , Plomo , Compuestos de Magnesio , Metales Pesados/análisis , Minería , Compuestos de Silicona , Contaminantes Químicos del Agua/análisis
18.
Opt Lett ; 47(10): 2450-2453, 2022 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-35561373

RESUMEN

We develop a general methodology capable of analyzing the response of Weyl semimetal (WSM) photogalvanic networks. Both single-port and multiport configurations are investigated via extended versions of Norton's theorem. An equivalent circuit model is provided where the photogalvanic currents induced in these gapless topological materials can be treated as polarization-dependent sources. To illustrate our approach, we carry out transport simulations in arbitrarily shaped configurations involving pertinent WSMs. Our analysis indicates that the photogalvanic currents collected in a multi-electrode system directly depend on the geometry of the structure as well as on the excitation and polarization pattern of the incident light. Our results could be helpful in designing novel optoelectronic systems that make use of the intriguing features associated with WSMs.

19.
Materials (Basel) ; 16(1)2022 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-36614459

RESUMEN

This research aims to evaluate the influences of the freeze-thaw (F-T) effect on the energy dissipation mechanism and damage evolution characteristics of muddy siltstones containing initial damage. At first, four initial damage levels were achieved by applying different impact loads to the intact rock, and the damage stresses for levels I, II, III, and IV initial damage were 9.80 Mpa, 17.00 Mpa, 23.34 Mpa, and 32.54 Mpa, respectively. Then dynamic compression tests were conducted on the muddy siltstones containing initial damage after 0, 5, 10, 15, 20, 25, 30, and 40 F-T cycles in the temperature range from -20 to 20 °C. The damage variable of the muddy siltstones was determined by studying energy distribution during fracture of the rock. The damage evolution characteristics of the muddy siltstone containing initial damage under the F-T effect were explored combined with the fractal theory. Test results show that (1) the dynamic compressive strength of the muddy siltstones decreases exponentially with the increasing number of F-T cycles; the dynamic compressive strength of muddy siltstone with different initial damage decreased by 54.9%, 48.4%, 39.4%, 42.5%, and 44.5% after 40 freeze-thaws, respectively, compared with that of intact. (2) The absorbed energy, reflected energy, and transmitted energy of the muddy siltstones subject to different levels of initial damage exhibit step-like changes under the effect of F-T cycles and the rate of decrease in absorbed energy decreases in the late stage of F-T cycles. (3) Both the damage variable and the fractal dimension of the muddy siltstones show an increasing trend with an increase in the number of F-T cycles, and it is more difficult for damage to become superimposed as the damage accumulates to that range causing fatigue (the damage variables ranged from 0.73 to 0.97) while the fractal dimension of the fracture surfaces in the rock still increases. (4) With the gradual increase in the damage variable, the energy absorption density of the rock is negatively correlated with the fractal dimension of the rock fragments.

20.
Environ Sci Pollut Res Int ; 28(9): 10519-10535, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33443738

RESUMEN

As one of the low-impact development measures, bioretention plays an important role in reducing the runoff peak flow and minimizing runoff pollutants, such as heavy metals, suspended solids, and nutrients. However, the efficiency of nitrogen removal in the bioretention system is unstable, owing to the different chemical properties of various forms of nitrogen and the limitations of current bioretention system for nitrogen transformation. This review article summarizes the recent advances in bioretention system in treatment of urban stormwater and agricultural runoff for nitrogen removal. The microbial characteristics and main processes of nitrogen transformation in bioretention are reviewed. The operational conditions affecting nitrogen removal, including climatic conditions, pH, wet-dry alternation, influent loads and nitrogen concentration, and hydraulic residence time are discussed. Finally, measures or strategies for increasing nitrogen removal efficiency are proposed from the perspectives of structural improvement of the bioretention system, optimization of medium composition, and enhancement of the nitrogen removal reaction processes.


Asunto(s)
Metales Pesados , Nitrógeno , Nutrientes , Lluvia
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