The exploring of catalysts with high‐efficiency and low‐cost for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is one of the key issues for many renewable energy systems ...including fuel cells, metal–air batteries, and water splitting. Despite several decades pursuing, bifunctional oxygen catalysts with high catalytic performance at low‐cost, especially the one that could be easily scaled up for mass production are still missing and highly desired. Herein, a hybrid catalyst with NiCo alloy nanoparticles decorated on N‐doped carbon nanofibers is synthesized by a facile electrospinning method and postcalcination treatment. The hybrid catalyst NiCo@N‐C 2 exhibits outstanding ORR and OER catalytic performances, which is even surprisingly superior to the commercial Pt/C and RuO2 catalysts, respectively. The synergetic effects between alloy nanoparticles and the N‐doped carbon fiber are considered as the main contributions for the excellent catalytic activities, which include decreasing the intrinsic and charge transfer resistances, increasing CC, graphitic‐N/pyridinic‐N contents in the hybrid catalyst. This work opens up a new way to fabricate high‐efficient, low‐cost oxygen catalysts with high production.
NiCo alloy nanoparticles decorated on N‐doped carbon nanofibers as a highly active and durable oxygen electrocatalyst at low‐cost are synthesized and reported. The hybrid catalyst with suitable amount of NiCo alloy nanoparticles loading (NiCo@N‐C 2) gives the most outstanding oxygen reduction reaction and oxygen evolution reaction electrocatalytic performances, which is even surprisingly superior to the commercial Pt/C and RuO2 catalysts, respectively.
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial reactions in energy conversion and storage systems including fuel cells, metal–air batteries, and electrolyzers. ...Developing low‐cost, high‐efficiency, and durable non‐noble bifunctional oxygen electrocatalysts is the key to the commercialization of these devices. Here, based on an in‐depth understanding of ORR/OER reaction mechanisms, recent advances in the development of non‐noble electrocatalysts for ORR/OER are reviewed. In particular, rational design for enhancing the activity and stability and scalable synthesis toward the large‐scale production of bifunctional electrocatalysts are highlighted. Prospects and future challenges in the field of oxygen electrocatalysis are presented.
Low‐cost and efficient bifunctional oxygen electrocatalysts are key to the commercialization of reversible fuel cells, metal–air batteries and electrolyzers. Herein, recent advances in the development of non‐noble bifunctional oxygen reduction reaction/oxygen evolution reaction electrocatalysts toward large‐scale production are presented, together with a discussion of the future challenges and prospects in this field.
Retinal pigment epithelium (RPE) cell damage is implicated in the pathogenesis of age‐related macular degeneration (AMD). An increase of interferon‐γ (IFN‐γ) levels was observed in patients with AMD, ...but whether inflammatory factors are causally related to AMD progression is unclear. Here, we demonstrate a direct causal relationship between IFN‐γ and RPE cell death. IFN‐γ induced human retinal pigment epithelial cell (ARPE‐19) death accompanied by increases in Fe2+, reactive oxygen species, lipid peroxidation, and glutathione (GSH) depletion, which are main characteristics of ferroptosis. Mechanistically, IFN‐γ upregulates the level of intracellular Fe2+ through inhibiting Fe2+ efflux protein SLC40A1 and induces GSH depletion by blocking cystine/glutamate antiporter, System xc‐. At the same time, treatment with IFN‐γ decreases the level of glutathione peroxidase 4 (GPx4), rendering the cells more sensitive to ferroptosis. JAK1/2 and STAT1 inhibitors could reverse the reduction of SLC7A11, GPx4 and GSH expression induced by IFN‐γ, indicating IFN‐γ induces ARPE‐19 cell ferroptosis via activation of the JAK1‐2/STAT1/SLC7A11 signaling pathway. The above results were largely confirmed in IFN‐γ‐treated mice in vivo. Finally, we used sodium iodate (NaIO3)‐induced retinal degeneration to further explore the role of ferroptosis in AMD in vivo. Consistent with the role of IFN‐γ, treatment with NaIO3 decreased SLC7A11, GPx4 and SLC40A1 expressions. NaIO3‐induced RPE damage was accompanied by increased iron, lipid peroxidation products (4‐hydroxynonenal, malondialdehyde), and GSH depletion, and ferroptosis inhibitors could reverse the above phenomenon. Taken together, our findings suggest that inhibiting ferroptosis or reducing IFN‐γ may serve as a promising target for AMD.
IFN‐γ downregulates the expression of SLC7A11 via JAK1‐2/STAT1 signaling pathway, which results in decreases in cysteine transport and, subsequently, decreased GSH synthesis. Simultaneously, IFN‐γ increases intracellular Fe2+ levels through the inhibition of SLC40A1. GSH depletion and Fe2+ accumulation cause retinal pigment epithelial cells ferroptosis and accelerate the progression of AMD.
The rapid development of network technology has revolutionized information dissemination and made it possible for various new communication channels to gradually seep into people’s daily lives. The ...primary task within the context of new media is the creation of agricultural products live e-commerce. This study first analyses and categorizes the preferences of product purchasers using a collaborative filtering process in order to achieve this. It then suggests a clustering algorithm based on ROCK that improves the link rather than the previously used distance as a criterion for cluster split and can successfully address the problem of data scarcity based on collaborative suggestion. The difficulties of live e-commerce entrepreneurship and the need of fostering new farmers’ live e-commerce entrepreneurship skills are also discussed in this essay. The case study illustrates that the research’s strategy can successfully examine the path towards developing new farmers’ live e-commerce skills.
The lithium–sulfur (Li–S) battery is one of the most promising high-energy-density secondary battery systems. However, it suffers from issues arising from its extremely complicated ...“solid–liquid–solid” reaction routes. In recent years, enormous advances have been made in optimizing Li–S batteries via the rational design of compositions and architectures. Nevertheless, a comprehensive and in-depth understanding of the practical reaction mechanisms of Li–S systems and their effect on the electrochemical performance is still lacking. Very recently, several important in situ optical spectroscopic techniques, including Raman, infrared and ultraviolet-visible spectroscopies, have been developed to monitor the real-time variations of the battery states, and a bridge linking the macroscopic electrochemical performance and microscopic architectures of the components has been set up, thus playing a critical role in scientifically guiding further optimal design of Li–S batteries. In this tutorial review, we provide a systematic summary of the state-of-the-art innovations in the characterization and optimal design of Li–S batteries with the aid of these in situ optical spectroscopic techniques, to guide a beginner to construct in situ optical spectroscopy electrochemical cells, and develop strategies for preventing long-chain polysulfide formation, dissolution and migration, thus alleviating the shuttle effect in Li–S batteries and improving the cell performances significantly.
Emerging infectious diseases, such as severe acute respiratory syndrome (SARS) and Zika virus disease, present a major threat to public health
. Despite intense research efforts, how, when and where ...new diseases appear are still a source of considerable uncertainty. A severe respiratory disease was recently reported in Wuhan, Hubei province, China. As of 25 January 2020, at least 1,975 cases had been reported since the first patient was hospitalized on 12 December 2019. Epidemiological investigations have suggested that the outbreak was associated with a seafood market in Wuhan. Here we study a single patient who was a worker at the market and who was admitted to the Central Hospital of Wuhan on 26 December 2019 while experiencing a severe respiratory syndrome that included fever, dizziness and a cough. Metagenomic RNA sequencing
of a sample of bronchoalveolar lavage fluid from the patient identified a new RNA virus strain from the family Coronaviridae, which is designated here 'WH-Human 1' coronavirus (and has also been referred to as '2019-nCoV'). Phylogenetic analysis of the complete viral genome (29,903 nucleotides) revealed that the virus was most closely related (89.1% nucleotide similarity) to a group of SARS-like coronaviruses (genus Betacoronavirus, subgenus Sarbecovirus) that had previously been found in bats in China
. This outbreak highlights the ongoing ability of viral spill-over from animals to cause severe disease in humans.
Cellulose has received a tremendous amount of attention both in academia and industry owing to its unique structural features, impressive physical–chemical properties, and wide applications. This ...natural polymer is originally used for packaging, paper, lightweight composites, and so forth and is now being developed for various new areas, such as antibacterial treatment, catalysis, water purification and separation, and biological and environmental analysis. In the current article, we summarize the recent developments in the self-assembly of cellulose with various species including metal ions and metal and metal oxide nanoparticles. Then we highlight several key application areas of cellulose-based composites by reviewing the recent representative literature in each area. A significant part of this review demonstrates some exciting innovations for a wide range of practical applications of cellulose-based composites. Some challenges are also discussed with a view toward future developments.
Metabolons, multiprotein complexes consisting of sequential enzymes of a metabolic pathway, are proposed to be biosynthetic "hotspots" within the cell. However, experimental demonstration of their ...presence and functions has remained challenging. We used metabolomics and in situ three-dimensional submicrometer chemical imaging of single cells by gas cluster ion beam secondary ion mass spectrometry (GCIB-SIMS) to directly visualize de novo purine biosynthesis by a multienzyme complex, the purinosome. We found that purinosomes comprise nine enzymes that act synergistically, channeling the pathway intermediates to synthesize purine nucleotides, increasing the pathway flux, and influencing the adenosine monophosphate/guanosine monophosphate ratio. Our work also highlights the application of high-resolution GCIB-SIMS for multiplexed biomolecular analysis at the level of single cells.
Pathological calcification represents an event that consequently leads to a distinct elevation in the morbidity and mortality of patients with chronic kidney disease (CKD) in addition to ...strengthening its correlation with hyperphosphatemia. Epigenomic regulation by specific microRNAs (miRNAs) is reported to be involved in ectopic calcification. However, the finer molecular mechanisms governing this event remain unclear. Hence, this study aimed to identify the potential miRNAs involved in vascular calcification (VC) development and progression. Initially, mitochondrial membrane potential (MMP), autophagy‐specific markers (LC3II/LC3I and Beclin1) and phenotype‐specific markers of osteoblasts (runt‐related transcription factor 2 and Msx2) were measured to evaluate autophagy and VC in β‐glycerophosphate‐induced vascular smooth muscle cells (VSMCs) with either miR‐30b restoration or miR‐30b knockdown performed in vitro. The VC in vivo was represented by calcified nodule formation in the aorta of the rats undergoing 5/6 nephrectomy followed by a 1.2% phosphorus diet using Alizarin Red staining. SOX9 was verified as the target of miR‐30b according to luciferase activity determination. Restoration of miR‐30b was revealed to markedly diminish the expression of SOX9 while acting to inhibit activation of the mTOR signaling pathway. Knockdown of miR‐30b reduced MMP and autophagy, elevated VC, and suppressed the presence of rapamycin (an inhibitor of the mTOR signaling pathway). In addition, upregulated expression of miR‐30b attenuated VC in vivo. Taken together, the key findings of this study identified the inhibitory role of miR‐30b in VC, presenting an enhanced understanding of miRNA as a therapeutic target to curtail progressive VC in hyperphosphatemia of CKD.
Our understanding of the diversity and evolution of vertebrate RNA viruses is largely limited to those found in mammalian and avian hosts and associated with overt disease. Here, using a large-scale ...meta-transcriptomic approach, we discover 214 vertebrate-associated viruses in reptiles, amphibians, lungfish, ray-finned fish, cartilaginous fish and jawless fish. The newly discovered viruses appear in every family or genus of RNA virus associated with vertebrate infection, including those containing human pathogens such as influenza virus, the Arenaviridae and Filoviridae families, and have branching orders that broadly reflected the phylogenetic history of their hosts. We establish a long evolutionary history for most groups of vertebrate RNA virus, and support this by evaluating evolutionary timescales using dated orthologous endogenous virus elements. We also identify new vertebrate-specific RNA viruses and genome architectures, and re-evaluate the evolution of vector-borne RNA viruses. In summary, this study reveals diverse virus-host associations across the entire evolutionary history of the vertebrates.
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