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Zinc-nitrate batteries can integrate energy supply, ammonia electrosynthesis, and sewage disposal into one electrochemical device. However, current zinc-nitrate batteries still severely suffer from the limited energy density and poor rechargeability. Here, we report the synthesis of tetraphenylporphyrin (tpp)-modified heterophase (amorphous/crystalline) rhodium-copper alloy metallenes (RhCu M-tpp). Using RhCu M-tpp as a bifunctional catalyst for nitrate reduction reaction (NO3RR) and ethanol oxidation reaction in neutral solution, a highly rechargeable and low-overpotential zinc-nitrate/ethanol battery is successfully constructed, which exhibits outstanding energy density of 117364.6 Wh kg-1cat, superior rate capability, excellent cycling stability of ~400 cycles, and potential ammonium acetate production. Ex/in situ experimental studies and theoretical calculations reveal that there is a molecule-metal relay catalysis in NO3RR over RhCu M-tpp that significantly facilitates the ammonia selectivity and reaction kinetics via a low energy barrier pathway. This work provides an effective design strategy of multifunctional metal-based catalysts toward the high-performance zinc-based hybrid energy systems.
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Electrochemical nitrate reduction reaction (NO3RR) to ammonia has been regarded as a promising strategy to balance the global nitrogen cycle. However, it still suffers from poor Faradaic efficiency (FE) and limited yield rate for ammonia production on heterogeneous electrocatalysts, especially in neutral solutions. Herein, we report one-pot synthesis of ultrathin nanosheet-assembled RuFe nanoflowers with low-coordinated Ru sites to enhance NO3RR performances in neutral electrolyte. Significantly, RuFe nanoflowers exhibit outstanding ammonia FE of 92.9% and yield rate of 38.68 mg h-1 mgcat-1 (64.47 mg h-1 mgRu-1) at -0.30 and -0.65 V (vs. reversible hydrogen electrode), respectively. Experimental studies and theoretical calculations reveal that RuFe nanoflowers with low-coordinated Ru sites are highly electroactive with an increased d-band center to guarantee efficient electron transfer, leading to low energy barriers of nitrate reduction. The demonstration of rechargeable zinc-nitrate batteries with large-specific capacity using RuFe nanoflowers indicates their great potential in next-generation electrochemical energy systems.
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Given the high energy density and eco-friendly characteristics, lithium-carbon dioxide (Li-CO2) batteries have been considered to be a next-generation energy technology to promote carbon neutral and space exploration. However, Li-CO2 batteries suffer from sluggish reaction kinetics, causing large overpotential and poor energy efficiency. Here, we observe enhanced reaction kinetics in aprotic Li-CO2 batteries with unconventional phase 4H/face-centered cubic (fcc) iridium (Ir) nanostructures grown on gold template. Significantly, 4H/fcc Ir exhibits superior electrochemical performance over fcc Ir in facilitating the round-trip reaction kinetics of Li+-mediated CO2 reduction and evolution, achieving a low charge plateau below 3.61 V and high energy efficiency of 83.8%. Ex situ/in situ studies and theoretical calculations reveal that the boosted reaction kinetics arises from the highly reversible generation of amorphous/low-crystalline discharge products on 4H/fcc Ir via the Ir-O coupling. The demonstration of flexible Li-CO2 pouch cells with 4H/fcc Ir suggests the feasibility of using unconventional phase nanomaterials in practical scenarios.
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Although metal-organic frameworks (MOFs) have attracted more attention for the electrocatalytic CO2 reduction reaction (CO2RR), obtaining multicarbon products with a high Faradaic efficiency (FE) remains challenging, especially under neutral conditions. Here, we report the controlled synthesis of stable Cu(I) 5-mercapto-1-methyltetrazole framework (Cu-MMT) nanostructures with different facets by rationally modulating the reaction solvents. Significantly, Cu-MMT nanostructures with (001) facets are acquired using isopropanol as a solvent, which favor multicarbon production with an FE of 73.75% and a multicarbon:single-carbon ratio of 3.93 for CO2RR in a neutral electrolyte. In sharp contrast, Cu-MMT nanostructures with (100) facets are obtained utilizing water, promoting single-carbon generation with an FE of 63.98% and a multicarbon: single-carbon ratio of only 0.18. Furthermore, this method can be extended to other Cu-MMT nanostructures with different facets in tuning the CO2 reduction selectivity. This work opens up new opportunities for the highly selective and efficient CO2 electroreduction to multicarbon products on MOFs via facet engineering.
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The controlled synthesis of metal nanomaterials with unconventional phases is of significant importance to develop high-performance catalysts for various applications. However, it remains challenging to modulate the atomic arrangements of metal nanomaterials, especially the alloy nanostructures that involve different metals with distinct redox potentials. Here we report the general one-pot synthesis of IrNi, IrRhNi and IrFeNi alloy nanobranches with unconventional hexagonal close-packed (hcp) phase. Notably, the as-synthesized hcp IrNi nanobranches demonstrate excellent catalytic performance towards electrochemical nitrite reduction reaction (NO2RR), with superior NH3 Faradaic efficiency and yield rate of 98.2 % and 34.6â mg h-1 mgcat -1 (75.5â mg h-1 mgIr -1) at 0 and -0.1â V (vs reversible hydrogen electrode), respectively. Ex/in situ characterizations and theoretical calculations reveal that the Ir-Ni interactions within hcp IrNi alloy improve electron transfer to benefit both nitrite activation and active hydrogen generation, leading to a stronger reaction trend of NO2RR by greatly reducing energy barriers of rate-determining step.
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BACKGROUND: Multimorbidity is better prevented in younger ages than in older ages. This study aims to identify the differences in comorbidity patterns in middle-aged inpatients from China and the United Kingdom (UK). METHODS: We utilized 184,133 and 180,497 baseline hospitalization records in middle-aged populations (40-59 years) from Shaanxi, China, and UK Biobank. Logistic regression was used to calculate odds ratios and P values for 43,110 unique comorbidity patterns in Chinese inpatients and 21,026 unique comorbidity patterns in UK inpatients. We included the statistically significant (P values adjusted by Bonferroni correction) and common comorbidity patterns (the pattern with prevalence > 1/10,000 in each dataset) and employed network analysis to construct multimorbidity networks and compare feature differences in multimorbidity networks for Chinese and UK inpatients, respectively. We defined hub diseases as diseases having the top 10 highest number of unique comorbidity patterns in the multimorbidity network. RESULTS: We reported that 57.12% of Chinese inpatients had multimorbidity, substantially higher than 30.39% of UK inpatients. The complete multimorbidity network for Chinese inpatients consisted of 1367 comorbidities of 341 diseases and was 2.93 × more complex than that of 467 comorbidities of 215 diseases in the UK. In males, the complexity of the multimorbidity network in China was 2.69 × more than their UK counterparts, while the ratio was 2.63 × in females. Comorbidities associated with hub diseases represented 68.26% of comorbidity frequencies in the complete multimorbidity network in Chinese inpatients and 55.61% in UK inpatients. Essential hypertension, dyslipidemia, type 2 diabetes mellitus, and gastritis and duodenitis were the hub diseases in both populations. The Chinese inpatients consistently demonstrated a higher frequency of comorbidities related to circulatory and endocrine/nutritional/metabolic diseases. In the UK, aside from these comorbidities, comorbidities related to digestive and genitourinary diseases were also prevalent, particularly the latter among female inpatients. CONCLUSIONS: Chinese inpatients exhibit higher multimorbidity prevalence and more complex networks compared to their UK counterparts. Multimorbidity with circulatory and endocrine/nutritional/metabolic diseases among both Chinese and UK inpatients necessitates tailored surveillance, prevention, and intervention approaches. Targeted interventions for digestive and genitourinary diseases are warranted for the UK.
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Diabetes Mellitus Tipo 2 , Enfermedades Metabólicas , Enfermedades Urogenitales , Masculino , Persona de Mediana Edad , Humanos , Femenino , Multimorbilidad , Diabetes Mellitus Tipo 2/epidemiología , Pacientes Internos , Comorbilidad , Enfermedades Metabólicas/epidemiología , Prevalencia , China/epidemiología , Reino Unido/epidemiologíaRESUMEN
An effective, nondestructive, and universal strategy to homogeneously modify freestanding carbon nanotube (CNT) films with various active species is essential to achieve functional electrodes for flexible electrochemical energy storage, which is challenging and has attracted considerable research interest. In this work, a generalizable concept, to utilize silicon oxide as the intermediate to uniformly decorate various metal sulfide nanostructures throughout CNT films is reported. Taking nickel sulfide nanosheet/CNT (NS/CNT) films, in which the NS nanosheets are homogeneously attached on the intact few-walled CNTs, as an example, the sheet-like NS provides sufficient active sites for redox reactions and the CNT network acts as an efficient electron highway, maintaining the structural integrity of the composite and also buffering volume changes. These merits enable NS/CNT films to meet the requirements of versatile energy storage applications. When used for supercapacitors, a high specific capacitance (2699.7 F g-1 /10 A g-1 ), outstanding rate performance at extremely high rates (1527 F g-1 /250 A g-1 ), remarkable cycling stability, and excellent flexibility can be achieved, among the best performance so far. Moreover, it also delivers excellent performance in the storage of Li and Na ions, meaning it is also potentially suitable for Li/Na ion batteries.
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OBJECTIVE: To assess the cost effectiveness of the second COVID-19 booster vaccination with different age groups. METHODS: We developed a decision-analytic Susceptible-Exposed-Infected-Recovered (SEIR)-Markov model by five age groups (0-4 years, 5-11 years 12-17 years, 18-49 years, and 50+ years) and calibrated the model by actual mortality in each age group in the USA. We conducted five scenarios to evaluate the cost effectiveness of the second booster strategy and incremental benefits if the strategy would expand to 18-49 years and 12-17 years, from a health care system perspective. The analysis was reported according to the Consolidated Health Economic Evaluation Reporting Standards 2022 statement. RESULTS: Implementing the second booster strategy for those aged ≥ 50 years cost $823 million but reduced direct medical costs by $1166 million, corresponding to a benefit-cost ratio of 1.42. Moreover, the strategy also resulted in a gain of 2596 quality-adjusted life-years (QALYs) during the 180-day evaluation period, indicating it was dominant. Further, vaccinating individuals aged 18-49 years with the second booster would result in an additional gain of $1592 million and 8790 QALYs. Similarly, expanding the vaccination to individuals aged 12-17 years would result in an additional gain of $16 million and 403 QALYs. However, if social interaction between all age groups was severed, vaccination expansion to ages 18-49 and 12-17 years would no longer be dominant but cost effective with an incremental cost-effectiveness ratio (ICER) of $37,572 and $26,705/QALY gained, respectively. CONCLUSION: The second booster strategy was likely to be dominant in reducing the disease burden of the COVID-19 pandemic. Expanding the second booster strategy to ages 18-49 and 12-17 years would remain dominant due to their social contacts with the older age group.
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COVID-19 , Análisis de Costo-Efectividad , Humanos , Anciano , Análisis Costo-Beneficio , Pandemias , COVID-19/prevención & control , Vacunación , Años de Vida Ajustados por Calidad de VidaRESUMEN
INTRODUCTION: The Joint United Nations Programme on HIV/AIDS (UNAIDS) updated the 95-95-95 targets for the HIV endgame in 2030. To achieve the first target in a timely manner, we investigate the optimized strategy of resource allocation to maximize timely HIV diagnosis in 14 populations in China. METHODS: We developed a mathematical model by integrating epidemiological, demographical and behavioural data from 12 high-risk and two general populations to evaluate the impact of various resource allocation strategies of HIV testing on HIV incidence in China. We identified the optimized allocation strategy that maximizes the number of HIV diagnoses at an estimated total spending on HIV tests in China and calculated the per-capita cost of new HIV case detection. RESULTS: We estimated that 144,795 new HIV cases may occur annually in 14 populations in China, with a total annual spending of US$2.8 billion on HIV testing. The largest proportion of spending was allocated to general males (44.0%), followed by general females (42.6%) and pregnant women (5.1%). Despite this allocation strategy, only 45.5% (65,867/144,795, timely diagnosis rate) of annual new infections were diagnosed within a year of acquisition, with a cost of $42,852 required for each new HIV case detection. By optimizing the allocation of HIV testing resources within the same spending amount, we found that general females received the highest proportion of spending allocation (45.1%), followed by low-risk men who have sex with men (13.9%) and pregnant women (8.4%). In contrast, the proportion of spending allocation for the general males decreased to 0.2%. With this optimized strategy, we estimated that 120,755 (83.4%) of annual new infections would be diagnosed within a year of acquisition, with the cost required for one HIV case detection reduced to $23,364/case. Further spending increases could allow for significant increases in HIV testing among lower-risk populations. CONCLUSIONS: Optimizing resource allocation for HIV testing in high-risk populations would improve HIV timely diagnosis rate of new infections and reduce cost per HIV case detection.
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Infecciones por VIH , Minorías Sexuales y de Género , Embarazo , Masculino , Humanos , Femenino , Homosexualidad Masculina , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , China/epidemiología , Asignación de RecursosRESUMEN
Electrocatalytic nitrate reduction reaction (NO3RR) toward ammonia synthesis is recognized as a sustainable strategy to balance the global nitrogen cycle. However, it still remains a great challenge to achieve highly efficient ammonia production due to the complex proton-coupled electron transfer process in NO3RR. Here, the controlled synthesis of RuMo alloy nanoflowers (NFs) with unconventional face-centered cubic (fcc) phase and hexagonal close-packed/fcc heterophase for highly efficient NO3RR is reported. Significantly, fcc RuMo NFs demonstrate high Faradaic efficiency of 95.2% and a large yield rate of 32.7 mg h-1 mgcat -1 toward ammonia production at 0 and -0.1 V (vs reversible hydrogen electrode), respectively. In situ characterizations and theoretical calculations have unraveled that fcc RuMo NFs possess the highest d-band center with superior electroactivity, which originates from the strong RuâMo interactions and the high intrinsic activity of the unconventional fcc phase. The optimal electronic structures of fcc RuMo NFs supply strong adsorption of key intermediates with suppression of the competitive hydrogen evolution, which further determines the remarkable NO3RR performance. The successful demonstration of high-performance zinc-nitrate batteries with fcc RuMo NFs suggests their substantial application potential in electrochemical energy supply systems.
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Copper (Cu) nanomaterials are a unique kind of electrocatalysts for high-value multi-carbon production in carbon dioxide reduction reaction (CO2RR), which holds enormous potential in attaining carbon neutrality. However, phase engineering of Cu nanomaterials remains challenging, especially for the construction of unconventional phase Cu-based asymmetric heteronanostructures. Here the site-selective growth of Cu on unusual phase gold (Au) nanorods, obtaining three kinds of heterophase fcc-2H-fcc Au-Cu heteronanostructures is reported. Significantly, the resultant fcc-2H-fcc Au-Cu Janus nanostructures (JNSs) break the symmetric growth mode of Cu on Au. In electrocatalytic CO2RR, the fcc-2H-fcc Au-Cu JNSs exhibit excellent performance in both H-type and flow cells, with Faradaic efficiencies of 55.5% and 84.3% for ethylene and multi-carbon products, respectively. In situ characterizations and theoretical calculations reveal the co-exposure of 2H-Au and 2H-Cu domains in Au-Cu JNSs diversifies the CO* adsorption configurations and promotes the CO* spillover and subsequent C-C coupling toward ethylene generation with reduced energy barriers.
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With the mechanical exfoliation of graphene in 2004, researchers around the world have devoted significant efforts to the study of two-dimensional (2D) nanomaterials. Nowadays, 2D nanomaterials are being developed into a large family with varieties of structures and derivatives. Due to their fascinating electronic, chemical, and physical properties, 2D nanomaterials are becoming an important type of catalyst for the electrochemical carbon dioxide reduction reaction (CO2RR). Here, we review the recent progress in electrochemical CO2RR using 2D nanomaterial-based catalysts. First, we briefly describe the reaction mechanism of electrochemical CO2 reduction to single-carbon (C1) and multi-carbon (C2+) products. Then, we discuss the strategies and principles for applying metal materials to functionalize 2D nanomaterials, such as graphene-based materials, metal-organic frameworks (MOFs), and transition metal dichalcogenides (TMDs), as well as applications of resultant materials in the electrocatalytic CO2RR. Finally, we summarize the present research advances and highlight the current challenges and future opportunities of using metal-functionalized 2D nanomaterials in the electrochemical CO2RR.
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Telomere length, as a biomarker of accelerated aging, is closely related to many chronic diseases. We aimed to explore the association between coffee consumption and telomere length. Our study included 468,924 participants from the UK Biobank. Multivariate linear models (observational analyses) were conducted to evaluate the associations of coffee intake, instant coffee intake, and filtered coffee intake with telomere length. In addition, we evaluated the causality of these associations in Mendelian randomization (MR) analyses by four methods (inverse-variance weighted (IVW), MR pleiotropy residual sum and outlier (MR-PRESSO), MR-Egger, and weighted median). Observational analyses indicated that coffee intake and instant coffee intake were negatively correlated with telomere length, which was equal to 0.12 year of age-related decrease in telomere length for each additional cup of coffee intake (p < 0.001), and 0.38 year of age-related decrease in telomere length for each additional cup of instant coffee intake (p < 0.001), respectively. There was no significant correlation between filtered coffee and telomere length (p = 0.862). Mendelian randomization analyses supported the results of observational analyses. Coffee intake was found to have a causal effect on telomere length through weighted median analysis (p = 0.022), and instant coffee intake had a causal effect on telomere length through IVW analysis (p = 0.019) and MR-PRESSO analysis (p = 0.028). No causal relationship was found between filtered coffee intake and telomere length (p > 0.05). Coffee intake, particularly instant coffee, was found to have an important role in shortening telomere length.
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Envejecimiento , Café , Análisis de la Aleatorización Mendeliana , Telómero , Humanos , Envejecimiento/genética , Bancos de Muestras Biológicas , Estudio de Asociación del Genoma Completo , Polimorfismo de Nucleótido Simple , Telómero/genética , Reino Unido , Café/efectos adversosRESUMEN
For resolving the problems of poor nitrogen removal efficiency and substandard effluent quality in wastewater treatment plants during winter, a cold-tolerant strain Glutamicibacter sp. WS1, with heterotrophic nitrification-aerobic denitrification ability, was isolated from activated sludge. The functional genes for nitrogen conversion of strain WS1 were amplified by PCR, and the nitrogen removal characteristics of the strain were verified under different nitrogen sources at 15â. In addition, the effects of environmental factors on the aerobic denitrification performance of the strain were explored at low temperature. Finally, a reasonable nitrogen metabolism pathway of strain WS1 was resolved based on functional genes and nitrogen balance analysis. The results showed that strain WS1 contained functional genes related to nitrogen conversion, including amoA, napA, nirS, and nirK genes. Notably, nirS and nirK genes coexisted in the strain. At the low temperature of 15â, with NH4+-N, NO3--N, NO2--N+NO3--N, and NH4+-N+NO3--N as nitrogen sources, the corresponding removal efficiencies of strain WS1 were 100%, 98.10%, 99.87%+100%, and 100%+94.92%, respectively. The optimal denitrification performance of the strain was achieved with sodium citrate as the carbon source, C/N of 16, pH of 8, DO of 4.5-6.8 mg·L-1, and temperature of 30â. In addition, the NO3--N removal efficiency of strain WS1 reached 92.50% under low temperature (15â) and low C/N (10) conditions. Based on the results of PCR amplification and nitrogen balance analysis, heterotrophic nitrification-aerobic denitrification/aerobic denitrification and assimilation were the main pathways for nitrogen substrate removal by strain WS1, in which most of the inorganic nitrogen (47%-56%) was converted to gaseous nitrogen through heterotrophic nitrification-aerobic denitrification/aerobic denitrification. Strain WS1 has broad application prospects in the treatment of low-temperature nitrogenous wastewater.
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Desnitrificación , Nitrógeno , Temperatura , Nitrificación , BacteriasRESUMEN
BACKGROUND: COVID-19 and diabetes both contribute to large global disease burdens. PURPOSE: To quantify the prevalence of diabetes in various COVID-19 disease stages and calculate the population attributable fraction (PAF) of diabetes to COVID-19-related severity and mortality. DATA SOURCES: Systematic review identified 729 studies with 29,874,938 COVID-19 patients. STUDY SELECTION: Studies detailed the prevalence of diabetes in subjects with known COVID-19 diagnosis and severity. DATA EXTRACTION: Study information, COVID-19 disease stages, and diabetes prevalence were extracted. DATA SYNTHESIS: The pooled prevalence of diabetes in stratified COVID-19 groups was 14.7% (95% CI 12.5-16.9) among confirmed cases, 10.4% (7.6-13.6) among nonhospitalized cases, 21.4% (20.4-22.5) among hospitalized cases, 11.9% (10.2-13.7) among nonsevere cases, 28.9% (27.0-30.8) among severe cases, and 34.6% (32.8-36.5) among deceased individuals, respectively. Multivariate metaregression analysis explained 53-83% heterogeneity of the pooled prevalence. Based on a modified version of the comparative risk assessment model, we estimated that the overall PAF of diabetes was 9.5% (7.3-11.7) for the presence of severe disease in COVID-19-infected individuals and 16.8% (14.8-18.8) for COVID-19-related deaths. Subgroup analyses demonstrated that countries with high income levels, high health care access and quality index, and low diabetes disease burden had lower PAF of diabetes contributing to COVID-19 severity and death. LIMITATIONS: Most studies had a high risk of bias. CONCLUSIONS: The prevalence of diabetes increases with COVID-19 severity, and diabetes accounts for 9.5% of severe COVID-19 cases and 16.8% of deaths, with disparities according to country income, health care access and quality index, and diabetes disease burden.
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COVID-19 , Diabetes Mellitus , Humanos , COVID-19/epidemiología , Prevalencia , Prueba de COVID-19 , Diabetes Mellitus/epidemiología , Medición de RiesgoRESUMEN
BACKGROUND: Australia implemented an mRNA-based booster vaccination strategy against the COVID-19 Omicron variant in November 2021. We aimed to evaluate the effectiveness and cost-effectiveness of the booster strategy over 180 days. METHODS: We developed a decision-analytic Markov model of COVID-19 to evaluate the cost-effectiveness of a booster strategy (administered 3 months after 2nd dose) in those aged ≥ 16 years, from a healthcare system perspective. The willingness-to-pay threshold was chosen as A$ 50,000. RESULTS: Compared with 2-doses of COVID-19 vaccines without a booster, Australia's booster strategy would incur an additional cost of A$0.88 billion but save A$1.28 billion in direct medical cost and gain 670 quality-adjusted life years (QALYs) in 180 days of its implementation. This suggested the booster strategy is cost-saving, corresponding to a benefit-cost ratio of 1.45 and a net monetary benefit of A$0.43 billion. The strategy would prevent 1.32 million new infections, 65,170 hospitalisations, 6,927 ICU admissions and 1,348 deaths from COVID-19 in 180 days. Further, a universal booster strategy of having all individuals vaccinated with the booster shot immediately once their eligibility is met would have resulted in a gain of 1,599 QALYs, a net monetary benefit of A$1.46 billion and a benefit-cost ratio of 1.95 in 180 days. CONCLUSION: The COVID-19 booster strategy implemented in Australia is likely to be effective and cost-effective for the Omicron epidemic. Universal booster vaccination would have further improved its effectiveness and cost-effectiveness.
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Vacunas contra la COVID-19 , COVID-19 , Humanos , Análisis Costo-Beneficio , COVID-19/prevención & control , SARS-CoV-2 , Vacunación , Australia/epidemiologíaRESUMEN
Prussian blue analogs (PBAs) with open and porous frameworks have attracted wide attention in alkali metal ion batteries due to their high theoretical specific capacities and fast ion insertion/extraction kinetics. However, abundant coordinated water usually exists in traditional PBAs synthesized in aqueous systems. Consequently, the competition between coordinated water and alkali ions easily causes the rapid structural collapse of PBAs during the repeated discharge/charge cycles, lowering the cycling stability, and rate performance of batteries. Besides, most reported PBAs adopt the cubic/particle-like morphologies with large sizes, which usually suffer from insufficient ion diffusion especially at high rates. Herein, a facile and general strategy for the synthesis of 2D CoCo, CuFe, CuCeFe, and CuCeCo-based PBA nanosheets is reported. As a proof-of-concept application, Co3 [Co(CN)6 ]2 nanosheets are evaluated as anode materials for lithium-ion batteries. Thanks to the lower coordinated water content, smaller impedance and higher lithium-ion diffusion coefficient, Co3 [Co(CN)6 ]2 nanosheets deliver a superior reversible capacity of 810.4 mAh g-1 at 100 mA g-1 , better rate performance, and higher cycling stability compared to common Co3 [Co(CN)6 ]2 cubes. Further studies indicate that the capacitance-controlled electrochemical behaviors dominate in the Co3 [Co(CN)6 ]2 nanosheets, giving rise to their excellent structural stability and superior lithium storage performance even at high rates.
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Electrocatalytic carbon dioxide reduction reaction (CO2 RR) holds significant potential to promote carbon neutrality. However, the selectivity toward multicarbon products in CO2 RR is still too low to meet practical applications. Here the authors report the delicate synthesis of three kinds of Ag-Cu Janus nanostructures with {100} facets (JNS-100) for highly selective tandem electrocatalytic reduction of CO2 to multicarbon products. By controlling the surfactant and reduction kinetics of Cu precursor, the confined growth of Cu with {100} facets on one of the six equal faces of Ag nanocubes is realized. Compared with Cu nanocubes, Ag65 -Cu35 JNS-100 demonstrates much superior selectivity for both ethylene and multicarbon products in CO2 RR at less negative potentials. Density functional theory calculations reveal that the compensating electronic structure and carbon monoxide spillover in Ag65 -Cu35 JNS-100 contribute to the enhanced CO2 RR performance. This study provides an effective strategy to design advanced tandem catalysts toward the extensive application of CO2 RR.
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In view of the significant differences in phosphorus removal processes by different steel slags, electric furnace slag was taken as the research object to discuss the effects of environmental factors, including the adsorption time and adsorption temperature, on phosphorus removal and to verify the phosphorus removal performances of steel slag for phosphate, pyrophosphate, and actual water bodies. With the help of spectral techniques including scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), X-ray fluorescence spectroscopy(XRF), and an X-ray diffractometer(XRD), the phosphorus removal mechanisms of steel slag were explored. Moreover, the phosphorus removal abilities of different absorptive media of steel slag, ceramsite, and zeolite were compared, and the safety performances of phosphorus removal by steel slag were evaluated. The results showed that the adsorption time significantly affected the phosphorus removal efficiency of steel slag. The phosphorus removal efficiencies of phosphate solutions with a concentration range of 1-20 mg·L-1 using steel slag could reach over 97% when the adsorption time was 30 min. The effect of temperature on phosphorus removal by steel slag was not significant. The pyrophosphate adsorption capacity of steel slag was weaker than that of orthophosphate, and the removal rate of pyrophosphate with an initial concentration of 3 mg·L-1 was 82.45%. Spectral analysis showed that the mechanisms of phosphorus removal by steel slag were chemical adsorption assisted by physical adsorption, and calcium-phosphorus was the main precipitate component. CaHPO4·2H2O was the main precipitate. Steel slag exhibited excellent phosphorus removal properties for removing phosphorus in the biological pond effluent and wetland system, achieving total phosphorus removal rates of 98.36% and 93.33%, respectively. In comparison, the phosphate removal performance of steel slag was better than that of ceramsite and zeolite, and the removal efficiencies of PO43- were 96%, 40%, and 10%, respectively. The contents of heavy metals in the leaching solution of steel slag met the requirements of the Class I standard of surface water; thus, the steel slag was safe and reliable.
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Boron-doped carbon nanotubes are a promising candidate for Li storage due to the unique electronic structure and high crystallinity brought by the boron dopants. However, the relatively low Li storage capacity has limited its application in the electrochemical energy storage field, which is mainly caused by the predominantly intact graphitic structure on their surface with limited access points for Li ion entering. Herein, we report a novel B-doped CNTs (py-B-CNTs) film, in which the CNTs possess intrinsically rough surface but flat internal graphitic structure. When used as a flexible anode material for LIBs, this py-B-CNTs film delivers significantly enhanced capacity than the conventional B-doped CNTs or the pristine CNTs films, with good rate capability and excellent cycling performance as well. Moreover, this flexible film also possesses excellent mechanical flexibility, making it capable of being used in a prototype flexible LIB with stable power output upon various bending states.