NH4+ ions as charge carriers show potential for aqueous rechargeable batteries. Studied here for the first time is the NH4+‐storage chemistry using electrodeposited manganese oxide (MnOx). MnOx ...experiences morphology and phase transformations during charge/discharge in dilute ammonium acetate (NH4Ac) electrolyte. The NH4Ac concentration plays an important role in NH4+ storage for MnOx. The transformed MnOx with a layered structure delivers a high specific capacity (176 mAh g−1) at a current density of 0.5 A g−1, and exhibits good cycling stability over 10 000 cycles in 0.5 M NH4Ac, outperforming the state‐of‐the‐art NH4+ hosting materials. Experimental results suggest a solid‐solution behavior associated with NH4+ migration in layered MnOx. Spectroscopy studies and theoretical calculations show that the reversible NH4+ insertion/deinsertion is accompanied by hydrogen‐bond formation/breaking between NH4+ and the MnOx layers. These findings provide a new prototype (i.e., layered MnOx) for NH4+‐based energy storage and contributes to the fundamental understanding of the NH4+‐storage mechanism for metal oxides.
NH4+ storage using electrodeposited manganese oxides (MnOx) is studied for the first time. MnOx exhibits structural transformation during charge/discharge in dilute ammonium acetate (NH4Ac) electrolyte. Experimental and theoretical results suggest that the reversible NH4+ insertion/deinsertion in layered MnOx is associated with hydrogen‐bond formation/breaking between NH4+ and the MnOx layers.
Conducting polymers (CPs) have been widely studied for electrochemical energy storage. However, the dopants in CPs are often electrochemically inactive, introducing “dead‐weight” to the materials. ...Moreover, commercial‐level electrode materials with high mass loadings (e.g., >10 mg cm−2) often encounter the problems of inferior electrical and ionic conductivity. Here, a redox‐active poly‐counterion doping concept is proposed to improve the electrochemical performance of CPs with ultra‐high mass loadings. As a study prototype, heptamolybdate anion (Mo7O246−) doped polypyrrole (PPy) is synthesized by electro‐polymerization. A 2 mm thick PPy electrode with mass loading of ≈192 mg cm−2 reaches a record‐high areal capacitance of ≈47 F cm−2, competitive gravimetric capacitance of 235 F g−1, and volumetric capacitance of 235 F cm−3. With poly‐counterion doping, the dopants also undergo redox reactions during charge/discharge processes, providing additional capacitance to the electrode. The interaction between polymer chains and the poly‐counterions enhances the electrical conductivity of CPs. Besides, the poly‐counterions with large steric hindrance could act as structural pillars and endow CPs with open structures for facile ion transport. The concept proposed in this work enriches the electrochemistry of CPs and promotes their practical applications.
A redox poly‐counterion doping concept is proposed to synthesize high performance conducting polymers for pseudocapacitive applications. As a study prototype, heptamolybdate anion doped polypyrrole is synthesized via electro‐polymerization. A 2 mm‐thick polypyrrole electrode (active mass: ≈0.2 g cm−2) reaches a record‐high areal capacitance of ≈47 F cm−2 with good rate capability.
Aqueous zinc‐sulfur (Zn‐S) batteries show great potential for unlocking high energy and safety aqueous batteries. Yet, the sluggish kinetic and poor redox reversibility of the sulfur conversion ...reaction in aqueous solution challenge the development of Zn‐S batteries. Here, we fabricate a high‐performance Zn‐S battery using highly water‐soluble ZnI2 as an effective catalyst. In situ experimental characterizations and theoretical calculations reveal that the strong interaction between I− and the ZnS nanoparticles (discharge product) leads to the atomic rearrangement of ZnS, weakening the Zn‐S bonding, and thus facilitating the electrochemical oxidation reaction of ZnS to S. The aqueous Zn‐S battery exhibited a high energy density of 742 Wh kg(sulfur)−1 at the power density of 210.8 W kg(sulfur)−1 and good cycling stability over 550 cycles. Our findings provide new insights about the iodide catalytic effect for cathode conversion reaction in Zn‐S batteries, which is conducive to promoting the future development of high‐performance aqueous batteries.
The reversible conversion of sulfur cathodes in aqueous Zn‐S batteries is realized by applying the highly water‐soluble ZnI2 catalyst. Experimental and computational results indicate that abundant iodide ions adsorbed on ZnS nanoparticles surface regulate the d‐band center of Zn, leading to atomic rearrangements, and therefore promoting the electro‐oxidation of ZnS to S.
Polyaniline (PANI) is a promising cathode material for aqueous rechargeable zinc batteries (ARZBs), mainly benefitting from its good electrical conductivity. The high conductivity of PANI requires ...high doping level, yet the introduced nonactive dopants (e.g., SO42−) limit the gravimetric capacity of PANI (usually < 180 mAh g−1). Herein, an electro‐active dopant (decavanadate anion, V10O286−) is employed to fabricate the PANI cathode (PANI‐V10O28) for ARZBs. The doped decavanadate anion with the sub‐nanometer structure can fully expose the V‐based active sites, exhibiting good electrochemical activity. Due to the steric hindrance effect as well as the strong interaction between decavanadate anions and PANI chains, the active dopants are trapped in the polymer chains, demonstrating good structural and electrochemical stability. PANI‐V10O28 achieves a record‐high gravimetric capacity of 355 mAh g−1 at 0.1 A g−1, which is significantly higher than other reported PANI cathodes. Experimental results suggest that the charge storage mechanism of PANI‐V10O28 includes reversible injection/extraction of Zn(H2O)2Cl42− ions in PANI, as well as the protonation/deprotonation of V10O286−. This work enriches the doping chemistry of conducting polymer and pushes the development of organic cathodes for ARZBs to a new stage.
An electrochemically active polyacid anion (Decavanadate, V10O286−) is used as the dopant to fabricate polyaniline (PANI) cathode material (PANI‐V10O28) for aqueous rechargeable zinc batteries (ARZBs). The electrode achieves a record‐high gravimetric capacity of 355 mAh g−1 at 0.1 A g−1, approximately twice those of the traditional PANI materials.
Exosomes, which are nano-vesicles produced by most cell types, play an irreplaceable role in cell-cell communication. They are extracellular small vesicles that can delivery various cargos of DNA, ...RNAs, proteins, and lipids. Because exosomes have different secretory components under physiological conditions and pathological conditions, it has been extensively studied in the field of diseases as a therapeutic target, as a drug/gene delivery vector and as a novel cancer marker. Despite the great development in recent decades, there are still many obstacles to be overcome, for example, the separation method is not standardized with low yield and poor stability, which limit its medical application. This review mainly summarizes the main progresses of isolation and identification techniques, diversity function and medical application of exosomes in recent years.
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Vanadium oxide is a promising pseudocapacitive electrode, but their capacitance, especially at high current densities, requires improvement for practical applications. Herein, a VOx@MoO3 composite ...electrode is constructed through a facile electrochemical method. Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy demonstrate a modification on the chemical environment and electronic structure of VOx upon the effective interaction with the thin layer of MoO3. A careful investigation of the electrochemical impedance spectroscopy data reveals much enhanced power capability of the composite electrode. More charge storage sites will also be created at/near the heterogeneous interface. Due to those synergistic effects, the VOx@MoO3 electrode shows excellent electrochemical performance. It provides a high capacitance of 1980 mF cm−2 at 2 mA cm−2. Even at the high current density of 100 mA cm−2, it still achieves 1166 mF cm−2 capacitance, which doubles the sum of single electrodes. The MoO3 layer also helps to prevent VOx structure deformation, and 94% capacitance retention over 10 000 cycles is obtained for the composite electrode. This work demonstrates an effective strategy to induce interactions between heterogeneous components and enhance the electrochemical performance, which can also be applied to other pseudocapacitive electrode candidates.
The VOx@MoO3 nanorod composite is obtained by a facile electrochemical method. The effective interaction between the two components induces synergistic effects which largely enhance the electrochemical performance. The composite shows a high capacitance of 1166 mF cm−2 at the high current density of 100 mA cm−2, which doubles the sum of single electrodes.
Background
An outbreak of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 was first detected in Wuhan, Hubei, China. People of all ages are susceptible to SARS-CoV-2 infection. No ...information on severe pediatric patients with COVID-19 has been reported. We aimed to describe the clinical features of severe pediatric patients with COVID-19.
Methods
We included eight severe or critically ill patients with COVID-19 who were treated at the Intensive Care Unit (ICU), Wuhan Children’s Hospital from January 24 to February 24. We collected information including demographic data, symptoms, imaging data, laboratory findings, treatments and clinical outcomes of the patients with severe COVID-19.
Results
The onset age of the eight patients ranged from 2 months to 15 years; six were boys. The most common symptoms were polypnea (8/8), followed by fever (6/8) and cough (6/8). Chest imaging showed multiple patch-like shadows in seven patients and ground-glass opacity in six. Laboratory findings revealed normal or increased whole blood counts (7/8), increased C-reactive protein, procalcitonin and lactate dehydrogenase (6/8), and abnormal liver function (4/8). Other findings included decreased CD16 + CD56 (4/8) and Th/Ts*(1/8), increased CD3 (2/8), CD4 (4/8) and CD8 (1/8), IL-6 (2/8), IL-10 (5/8) and IFN-γ (2/8). Treatment modalities were focused on symptomatic and respiratory support. Two critically ill patients underwent invasive mechanical ventilation. Up to February 24, 2020, three patients remained under treatment in ICU, the other five recovered and were discharged home.
Conclusions
In this series of severe pediatric patients in Wuhan, polypnea was the most common symptom, followed by fever and cough. Common imaging changes included multiple patch-like shadows and ground-glass opacity; and a cytokine storm was found in these patients, which appeared more serious in critically ill patients.
Acute respiratory disease caused by 2019 novel coronavirus (2019‐nCoV) has rapidly spread throughout China. Children and adults show a different clinical course. The purpose of the current study is ...to comparatively analyze the clinical characteristics of 2019‐nCoV infection in children and adults and to explore the possible causes for the discrepancies present. The medical records of 25 adults and 7 children confirmed cases of 2019‐2019‐nCoV acute respiratory diseases were reviewed retrospectively. All children were family clusters. The total adult patients were differentiated into the local residents of Wuhan, a history of travel to Wuhan and direct contact with people from Wuhan. The numbers were 14 (56%), 10 (40%), and 1 (4%), respectively. The median incubation period of children and adults was 5 days (ranged, 3‐12 days) and 4 days (ranged, 2‐12 days), respectively. Diarrhoea and/or vomiting (57.1%) were demic by World Health Organiza more common in children, whereas for adults it was myalgia or fatigue (52%). On admission, the percentage of children having pneumonia (5%, 71.4%) was roughly the same as adults (20%, 80%). A total of 20% of adults had leucopoenia, but leukocytosis was more frequently in children (28.6%, P=.014). A higher number of children had elevated creatine kinase isoenzyme (57.1% vs 4%, P=.004). Antiviral therapy was given to all adult patients but to none of the children. In summary, knowledge of these differences between children and adults will not only be helpful for the clinical diagnosis of 2019‐nCoV disease, but also for a future discussion on age‐specific coronavirus infection.
Highlights
The routes of infection were more diverse in adults than children.
Diarrhoea and/or vomiting were more common in children, whereas for adults it was myalgia or fatigue.
More adults had leucopoenia, but leukocytosis was more frequently in children.
A higher number of children had elevated creatine kinase isoenzyme.
The percentage of children having pneumonia was roughly the same as adults.
Deep learning has been extensively applied to segmentation in medical imaging. U-Net proposed in 2015 shows the advantages of accurate segmentation of small targets and its scalable network ...architecture. With the increasing requirements for the performance of segmentation in medical imaging in recent years, U-Net has been cited academically more than 2500 times. Many scholars have been constantly developing the U-Net architecture. This paper summarizes the medical image segmentation technologies based on the U-Net structure variants concerning their structure, innovation, efficiency, etc.; reviews and categorizes the related methodology; and introduces the loss functions, evaluation parameters, and modules commonly applied to segmentation in medical imaging, which will provide a good reference for the future research.
VOPO4⋅x H2O has been proposed as a cathode for rechargeable aqueous zinc batteries. However, it undergoes significant voltage decay in conventional Zn(OTf)2 electrolyte. Investigations show the ...decomposition of VOPO4⋅x H2O into VOx in the electrolyte and voltage drops after losing the inductive effect from polyanions.PO43− was thus added to shift the decomposition equilibrium. A high concentration of cheap, highly soluble ZnCl2 salt in the electrolyte further prevents VOPO4⋅x H2O dissolution. The cathode shows stable capacity and voltage retentions in 13 m ZnCl2/0.8 m H3PO4 aqueous electrolyte, in direct contrast to that in Zn(OTf)2 where the decomposition product VOx provides most electrochemical activity over cycling. Sequential H+ and Zn2+ intercalations into the structure are revealed, delivering a high capacity (170 mAh g−1). This work shows the potential issue with polyanion cathodes in zinc batteries and proposes an effective solution using fundamental chemical principles.
The VOPO4⋅x H2O cathode undergoes decomposition and dissolution in rechargeable aqueous Zn batteries. A 13 m ZnCl2/0.8 m H3PO4 aqueous electrolyte is designed to inhibit its degradation, allowing stable capacity and voltage retentions over cycling. Sequential H+ and Zn2+ intercalations into the structure deliver a high capacity of 170 mAh g−1.
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