Abstract Cold seeps, where cold hydrocarbon-rich fluid escapes from the seafloor, showed strong enrichment of toxic metalloid arsenic (As). The toxicity and mobility of As can be greatly altered by microbial processes that play an important role in global As biogeochemical cycling. However, a global overview of genes and microbes involved in As transformation at seeps remains to be fully unveiled. Using 87 sediment metagenomes and 33 metatranscriptomes derived from 13 globally distributed cold seeps, we show that As detoxification genes ( arsM, arsP, arsC1 / arsC 2, acr3 ) were prevalent at seeps and more phylogenetically diverse than previously expected. Asgardarchaeota and a variety of unidentified bacterial phyla (e.g. 4484-113, AABM5-125-24 and RBG-13-66-14) may also function as the key players in As transformation. The abundances of As-cycling genes and the compositions of As-associated microbiome shifted across different sediment depths or types of cold seep. The energy-conserving arsenate reduction or arsenite oxidation could impact biogeochemical cycling of carbon and nitrogen, via supporting carbon fixation, hydrocarbon degradation and nitrogen fixation. Overall, this study provides a comprehensive overview of As-cycling genes and microbes at As-enriched cold seeps, laying a solid foundation for further studies of As cycling in deep sea microbiome at the enzymatic and processual levels.
Great interest has been taken in oxygen reduction reaction (ORR), as a common cathode reaction in new energy sources such as fuel cells and metal–air batteries, to improve the current energy structure and develop new green energy sources. Noble metal Pt is still considered the best catalyst for this reaction. However, its disadvantages such as high cost, low selectivity, poor stability, and susceptibility to impurity poisoning severely limit its further industrial applications. Therefore, development of efficient and low-cost ORR reduction catalysts is particularly critical. M-Nx-C materials have been extensively studied to achieve a high ORR activity close to that of Pt catalysts. In this study, CoNi bimetallic alloy carbon-based oxygen reduction catalysts named CoNi-950 (Zn) were successfully synthesized, using a metal–organic framework (MOF) as a carbon precursor and a nitrogen source. The experimental results show that CoNi-950 (Zn) exhibits good ORR catalytic performance with an ultimate current density of 6.27 mA cm–2, which even exceeds that of some Pt/C catalysts with a mass loading of 20 wt % (5.92 mA cm–2). In addition, the active site of the catalyst was also identified by acid leaching and SCN– poisoning experiments, showing two sites in the form of CoNi-Nx and the CoNi alloy or its oxides in the material. Further experiments demonstrate that these two active sites have distinct ORR catalytic mechanisms, generating positive synergism in ORR. A mechanism in which O2 was catalytically reduced by CoNi-950 (Zn) in a four-electron transfer, i.e., a continuous two-step dual-electron transfer reduction process in alkaline electrolytes, is proposed.
A flexible supercapacitor with favorable and stable electrochemical performance was prepared by using 3D printed CNF/MWCNT/MXene films and CNF/PAM hydrogel electrolyte.
Ethnopharmacological relevancePolygonum capitatum Buch.-Ham. ex D. Don (Pc, DB52/YC141-2003), a traditional herbal medicine of the Miao nationality, has been recognized for its therapeutic potential and efficacy in treating various urologic disorders, notably chronic bacterial prostatitis(CBP).Experimental and clinical evidence implicates Pc combination Ciprofloxacin(CIP) can effectively improve the clinical symptoms of CBP patients with urinary symptoms.Combination therapies are superior to monotherapy for CBP.However, the underlying mechanisms and constituents responsible for this synergistic effect remain elusive, limiting its implementation in clinical settings.Aim of the studyThis study aims to elucidate the potential synergistic mechanism of Pc and CIP in ameliorating CBP, and to find out which the major active ingredient of Pc contributed the most to the therapeutic efficacy combined with CIP.Materials and methodsCBP was induced by prostate bilateral injections of Escherichia coli (E. coli.) and treated with Pc combined with CIP.The therapeutic effect of Pc combined with CIP was assessed, prostate index, and bacterial colonization were quantified.The morphological changes of the prostate were observed by HE staining.Expressions of inflammatory mediators were measured by Western blotting (WB), qRT-PCR, and immunohistochemical staining.Transcriptome data were analyzed using Ingenuity Pathway Analysis (IPA) to elucidate the molecular mechanisms underlying the Pc combined with CIP, and key targets were verified by qRT-PCR and WB.Furthermore, tissue-thermal proteome profiling (Tissue-TPP) was conducted to identify potential targets of Pc combined with CIP, and the binding of Pc combined with CIP to these targets was validated using thermal shift assays.Molecular docking was conducted to predict the binding interactions between active compounds and key target proteins.Finally, the therapeutic effect of active ingredients in Pc combined with CIP was assessed.ResultsThe results indicated that Pc combined with CIP significantly reduced the prostatic index and bacterial concentration, restored the prostate gland structure, and inhibited the mRNA and protein expression of pro-inflammatory factors (TNF-α and IL-1β) in CBP rats.RNA-Seq combined with IPA analysis showed that Pc combined with CIP significantly inhibited inflammatory signaling pathway in CBP rats, especially the NF-κB/IL-6/JAK2/STAT3 pathway.Moreover, Tissue-TPP and thermal shift assays revealed that Pik3cb is a direct target of Pc combined with CIP, and molecular docking found that gallic acid (GA) can directly bind to Pik3cb, a predominant component of Pc.Finally, GA combined with CIP was also found to significantly improve CBP.ConclusionThe results suggest that Pc combined with CIP can mitigate CBP by targeting Pik3cb to inhibit the NF-κB/IL-6/JAK2/STAT3 signaling pathway, and GA is the key active component in Pc.
The intrinsic activity of catalysts is crucial for the electrocatalytic hydrogen evolution reaction, which is essentially dependent on their crystal structure and surface electronic state. The variable crystalline phase in tungsten oxide (WO3) can provide a favorable opportunity for modulating surface electronic state. In this work, the structure–activity relationship of the representative hexagonal and monoclinic phase WO3 (h-WO3 and m-WO3) for the hydrogen evolution reaction was discussed in detail by experimental techniques combined with density functional theory (DFT) calculations. DFT calculations reveal that m-WO3 exhibits the modest H-adsorption/desorption energy, which is beneficial to the fast desorption of active H* intermediate compared to h-WO3, displaying superior catalytic activity in the hydrogen evolution reaction. To accelerate the charge transfer, introduction of reduced graphene oxide (rGO) further amplifies the intrinsic catalytic activity endowed with this crystalline phase. In acid media, the m-WO3/rGO catalyst shows a low Tafel slope of 32 mV dec–1, requires an overpotential of only 35 mV to drive a current density of 10 mA cm–2, and keeps excellent stability during accelerated durability test. This work presents significance of crystalline phase for optimizing the intrinsic activity of catalyst and provides a novel idea to design a high-efficient catalyst for the hydrogen evolution reaction.
To explore next-generation flexible supercapacitors, lightweight, superior conductivity, low cost, and excellent capacitance are the preconditions for practical use. However, subjected to unsatisfactory conductivity, limited surface areas, and poor porosity leading to long ion transport channels, carbon fiber (CF)-based flexible supercapacitors need to further boost the electrochemical properties. Hence, a porous reduced graphene oxide encapsulated Cu(OH)2 core-shell structured CF-based electrode was fabricated through a scalable approach. The inexpensive Cu(OH)2 nanoarrays were controllably grown in situ on a CF substrate, with residual Cu promoting conductivity. Porous graphene oxide (PrGO), which served as the shell, was realized by Ni nanoparticle etching, which not only provided more active sites for capacitance as well as shortened accessible pathways for the ion transport but also effectively alleviated the exfoliation of the internal active materials. Moreover, thanks to this distinctive core-shell architecture, the extra space between the outer PrGO layer and the internal ordered Cu(OH)2 nanoarrays provided increased space for capacitance storage. The assembled PrGO/Cu(OH)2/Cu@CF electrode exhibited an excellent areal capacitance, reaching up to 722 mF cm-2 at a current density of 0.5 mA cm-2, attributed to its superior structure and materials advantages. The resulting PrGO/Cu(OH)2/Cu@CF//AC//CF asymmetric flexible all-solid-state supercapacitor achieved a high energy density of 0.052 mWh cm-2 and exhibited long-term durability. This work proposes a low-cost and effective way to fabricate hierarchically structured electrodes for wearable CF-based supercapacitors.
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