Developing effective ways to recycle rusted stainless steel and to promote the sluggish oxygen evolution reaction (OER), associated with water splitting and metal–air batteries, is important for a ...resource‐sustainable and environment‐friendly society. Herein, we propose a strategy to enable rusted stainless steel plate to be used as an abundant and low‐cost OER catalyst, wherein a hydrothermal combined in situ electrochemical oxidation–reduction cycle (EORC) method is developed to mimic and expedite the corrosion process, and thus activate stainless steel into free‐standing OER electrodes. Benefiting from the plentiful electrolyte‐accessible Fe/(Ni) oxyhydroxides, high conductivity and mechanical stability, this electrode exhibits remarkable OER performances including low overpotential, fast kinetics, and long‐term durability. The slight degradation in current after long‐term use can be repaired immediately in situ by an EORC.
To turn waste into treasure, rusty stainless steel is recycled into low‐cost, efficient, free‐standing oxygen evolution reaction (OER) electrodes via an electrochemical oxidation–reduction cycle in an electrolyte.
Li‐ion batteries (LIBs) with excellent cycling stability and high‐energy densities have already occupied the commercial rechargeable battery market. Unfortunately, the high cost and intrinsic ...insecurity induced by organic electrolyte severely hinder their applications in large‐scale energy storage. In contrast, aqueous Zn‐ion batteries (ZIBs) are being developed as an ideal candidate because of their cheapness and high security. Benefiting from high operating voltage and acceptable specific capacity, recently, manganese‐based oxides with different various crystal structures have been extensively studied as cathode materials for aqueous ZIBs. This review presents research progress of manganese‐based cathodes in aqueous ZIBs, including various manganese‐based oxides and their zinc storage mechanisms. In addition, we also discuss some optimization strategies that aim at improving the electrochemical performance of manganese‐based cathodes, and the design of flexible aqueous ZIBs based on manganese‐based cathodes (MZIBs). Finally, this review summarizes some valuable research directions, which will promote the further development of aqueous MZIBs.
Benefiting from high operating voltage and acceptable specific capacity, recently, manganese‐based oxides with different various crystal structures have been extensively studied as cathode materials for aqueous ZIBs. This review presents research progress of manganese‐based cathodes in aqueous ZIBs, including various manganese‐based oxides and their zinc storage mechanisms, optimization strategies, and the design of flexible aqueous ZIBs based on manganese‐based cathodes (MZIBs). Besides, some valuable research directions for aqueous MZIBs are also discussed.
Electroactive microorganisms (EAMs) are ubiquitous in nature and have attracted considerable attention as they can be used for energy recovery and environmental remediation via their extracellular ...electron transfer (EET) capabilities. Although the EET mechanisms of Shewanella and Geobacter have been rigorously investigated and are well characterized, much less is known about the EET mechanisms of other microorganisms. For EAMs, efficient EET is crucial for the sustainable economic development of bioelectrochemical systems (BESs). Currently, the low efficiency of EET remains a key factor in limiting the development of BESs. In this review, we focus on the EET mechanisms of different microorganisms, (i.e., bacteria, fungi, and archaea). In addition, we describe in detail three engineering strategies for improving the EET ability of EAMs: (1) enhancing transmembrane electron transport via cytochrome protein channels; (2) accelerating electron transport via electron shuttle synthesis and transmission; and (3) promoting the microbe-electrode interface reaction via regulating biofilm formation. At the end of this review, we look to the future, with an emphasis on the cross-disciplinary integration of systems biology and synthetic biology to build high-performance EAM systems.
•Extracellular electron transfer mechanisms are summarized.•Extracellular electron transport pathways of microorganisms are summarized.•Engineering strategies for improving EET capabilities are reviewed.•New insights on further EET research are presented.
Application of biochars to remove inorganic nitrogen (NH4+, NO2−, NH3, NO, NO2, N2O) from wastewater and agricultural fields has gained a significant interest. This study aims to investigate the ...relationship between ammonium sorption and physicochemical properties of biochars derived from different kinds of fruit peel. Biochars from three species of fruit peel (orange, pineapple and pitaya) were prepared at 300, 400, 500 and 600 °C with the residence time of 2 h and 4 h. Their characteristics and sorption for ammonium was evaluated. The results show a clear effect of pyrolysis conditions on physicochemical properties of biochars, including elemental composition, functional groups and pH. The maximum NH4+ adsorption capacities were associated with biochars of orange peel (4.71 mg/g) and pineapple peel (5.60 mg/g) produced at 300 °C for 2 h. The maximum NH4+ adsorption capacity of the pitaya peel biochar produced at 400 °C for 2 h was 2.65 mg/g. For all feedstocks, biochars produced at low temperatures showed better NH4+ adsorption capacity. It was found that biochars had better adsorption efficiency on ammonium at a pH of 9. Adsorption kinetics of ammonium on biochars followed the pseudo-second-order kinetic model while Langmuir isotherm model could well simulate the adsorption behavior of ammonium on biochars. The adsorption mechanism of ammonium on biochars predominantly involved surface complexation, cation exchange and electrostatic attraction. Conclusively, the fruit peel-derived biochars can be used as an alternative to conventional sorbents in water treatment.
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•Biochars from three kinds of fruit peel were prepared.•Biochar derived from pineapple peel had a higher sorption capacity for NH4+.•Elemental and functional groups play a critical role in adsorption of NH4+.•Biochar has better adsorption capacity for ammonium at low temperature.•Chemical adsorption is the dominant mechanism of NH4+ adsorption.
Projection artifacts in optical coherence tomography angiography (OCTA) blur the retinal vascular plexuses together and limit visualization of the individual plexuses.
To describe projection-resolved ...(PR) OCTA in eyes with diabetic retinopathy (DR) and healthy eyes.
In this case-control study, patients with DR and healthy controls were enrolled in this observational study from January 26, 2015, to December 4, 2015, at a tertiary academic center. Spectral-domain, 70-kHz OCT obtained 3 × 3-mm macular scans. The PR algorithm suppressed projection artifacts. A semiautomated segmentation algorithm divided PR-OCTA into superficial, intermediate, and deep retinal plexuses. Two masked graders examined 3-layer PR-OCTA and combined angiograms for nonperfusion and abnormal capillaries.
Retinal nonperfusion and capillary abnormalities and the diagnostic accuracy of detecting DR.
Twenty-nine eyes of 15 healthy individuals (mean SD age, 36.2 13.4 years; 11 women) and 47 eyes of 29 patients with DR (mean SD age, 55.5 11.9; 10 women) underwent imaging. PR-OCTA revealed 3 distinct retinal plexuses in their known anatomical locations in all eyes. The intermediate and deep plexuses of healthy eyes revealed capillary networks of uniform density and caliber, whereas the superficial plexus revealed vessels in the familiar centripetal branching pattern. In eyes with DR, 3-layer PR-OCTA disclosed incongruent areas of nonperfusion and varied vessel caliber and density in the deeper plexuses. Masked grading of capillary nonperfusion on 3-layer PR-OCTA detected DR with 100% sensitivity (95% CI, 90.8%-100%) and 100% specificity (95% CI, 85.4%-100%). With unsegmented retinal angiograms, the sensitivity and specificity were 78.7% (95% CI, 63.9%-88.8%) and 100% (95% CI, 85.4%-100%), respectively (P = .002 for sensitivity). On 3-layer PR-OCTA, sensitivity was 72.2% (95% CI, 54.6%-85.2%) for severe nonproliferative DR and proliferative DR eyes with generalized nonperfusion in 2 or more individual plexuses, but on combined angiogram, sensitivity was 25.0% (95% CI, 12.7%-42.5%) for generalized nonperfusion (P < .001). PR-OCTA disclosed dilated vessels in the intermediate and deep plexuses in 23 eyes (100%) with proliferative DR, 13 eyes (100%) with severe nonproliferative DR, 8 eyes (73%) with mild to moderate nonproliferative DR, and 0 control eyes.
By presenting 3 retinal vascular plexuses distinctly, PR-OCTA reveals capillary abnormalities in deeper layers with clarity and may distinguish DR from healthy eyes and severe DR from mild DR with greater accuracy compared with conventional OCTA.
Efficient oxygen electrocatalysts are the key elements of numerous energy storage and conversion devices, including fuel cells and metal-air batteries. In order to realize their practical ...applications, highly efficient and inexpensive non-noble metal-based oxygen electrocatalysts are urgently required. Herein, we report a novel iron-chelated urea-formaldehyde resin hydrogel for the synthesis of Fe-N-C electrocatalysts. This novel hydrogel is prepared using a new instantaneous （20 s） one-step scalable strategy, which theoretically ensures the atomic-level dispersion of Fe ions in the urea-formaldehyde resin, guaranteeing the microstructural homogeneity of the electrocatalyst. Consequentl~ the prepared electrocatalyst exhibits higher catalytic activity and durability in the oxygen reduction （ORR） and evolution （OER） reactions than the commercial Pt/C catalyst. Furthermore, the above catalyst also shows a much better performance in rechargeable Zn-air batteries, including higher power density and better cycling stability. The developed synthetic approach opens up new avenues toward the development of sustainable active electrocatalysts for electrochemical energy devices.
Five nanoporous carbons (NPCs) were prepared by polymerizing and then carbonizing carbon precursor of furfuryl alcohol accommodated in a porous metal–organic framework (MOF-5, Zn
4O(bdc)
3, bdc
=
...1,4-benzenedicarboxylate) template. The Brunauer–Emmett–Teller (BET) surface areas for five NPC samples obtained by carbonizing at the temperatures from 530 to 1000
°C fall into the range from 1140 to 3040
m
2
g
−1 and the dependence of BET surface areas on carbonization temperatures shows a “
V” shape. All the five NPC samples have a pore size distribution centered at about 3.9
nm. As electrode materials for supercapacitor, the NPC samples obtained at the temperatures higher than 600
°C display the ideal capacitor behaviors and give rise to almost constant specific capacitance (above 100
F
g
−1 at 5
mV
s
−1) at various sweep rates, which is associated with their mesoporous characteristics. However, the NPC sample with the highest BET surface area (3040
m
2
g
−1) obtained by carbonizing at 530
°C gives a unusually low capacitance (12
F
g
−1 at 5
mV
s
−1), which may be attributed to the poor conductivity of the carbon material due to the low carbonization temperature.
Flexible metal–air batteries, which are a promising candidate for implantation in wearable or rolling‐up electronic devices, have attracted much attention recently due to their relatively high energy ...density. Various flexible metal–air batteries have been developed recently, including flexible nonaqueous lithium–air batteries, aqueous zinc–air batteries, and aqueous aluminum–air batteries. Although various viable configurations of flexible metal–air batteries have been proposed, challenges regarding electrode design, electrolyte exploitation, and low practical energy density, still exist. Here, a brief introduction is presented as to the recent development of flexible metal–air batteries, regarding the electrodes, electrolyte, and prototype devices. Also, a general perspective on the current challenges and recommended future research directions for the practical use of metal–air batteries is provided.
Flexible metal–air batteries are identified as one of the most promising candidates for use in flexible energy‐storage devices, such as portable and wearable electronics. The development of the flexible electrode design, electrolyte exploitation, and the assembly of prototype batteries are comprehensively reviewed. The major challenges and perspectives for flexible metal–air batteries are also discussed.
•29 Selected antibiotics were found to be prevalent in four reservoirs.•Seasonal variations of most antibiotics were significant.•Antibiotics occurrence at the reservoir was related to cage culture ...of fish.•Alage, daphnid and fish might be at low short-term risk in the reservoir.
The occurrence and seasonal variability of five groups (tetracycline, quinolone, chloramphenicol, macrolide and sulfonamide) of antibiotics were investigated in the surface water of four reservoirs. The dissolved concentrations of 29 antibiotics were in the ngL−1 level. Trace levels of all target antibiotics were analyzed using solid-phase extraction followed by liquid chromatography electrospray tandem mass spectrometry. All of the antibiotics were detected at all sampling sites, indicating widespread occurrence of antibiotics in the study area. The detection of florfenicol, josamycin, kitasamycin, spiramycin and sulfameter is the first report of these compounds in reservoir samples. The results showed an association between the presence of some antibiotics at Panjiakou reservoir and cage culture of fish. Twenty-three types of antibiotics showed significant seasonal variations (p<0.001) due to human activities and flow conditions. A risk assessment showed that all antibiotics detected could cause very low risk to algae, daphnid and fish. Further health risk need to be investigated because these reservoirs are drinking water sources.
Due to the heavy and expanding agricultural use of neurotoxic pesticides suspected to affect dopaminergic neurons, it is imperative to closely examine the role of pesticides in the development of ...Parkinson's disease (PD). We focus our investigation on pesticide use in California's heavily agricultural central valley by utilizing a unique pesticide use reporting system. From 2001 to 2007, we enrolled 362 incident PD cases and 341 controls living in the Central Valley of California. Employing our geographic information system model, we estimated ambient exposures to the pesticides ziram, maneb, and paraquat at work places and residences from 1974 to 1999. At workplaces, combined exposure to ziram, maneb, and paraquat increased risk of PD three-fold (OR: 3.09; 95% CI: 1.69, 5.64) and combined exposure to ziram and paraquat, excluding maneb exposure, was associated with a 80% increase in risk (OR: 1.82; 95% CI: 1.03, 3.21). Risk estimates for ambient workplace exposure were greater than for exposures at residences and were especially high for younger onset PD patients and when exposed in both locations. Our study is the first to implicate ziram in PD etiology. Combined ambient exposure to ziram and paraquat as well as combined ambient exposure to maneb and paraquat at both workplaces and residences increased PD risk substantially. Those exposed to ziram, maneb, and paraquat together experienced the greatest increase in PD risk. Our results suggest that pesticides affecting different mechanisms that contribute to dopaminergic neuron death may act together to increase the risk of PD considerably.
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