RESUMO
Stereocilia are F-actin-based protrusions on the apical surface of inner-ear hair cells and are indispensable for hearing and balance perception. The stereocilia of each hair cell are organized into rows of increasing heights, forming a staircase-like pattern. The development and maintenance of stereocilia are tightly regulated, and deficits in these processes lead to stereocilia disorganization and hearing loss. Previously, we showed that the F-BAR protein FCHSD2 is localized along the stereocilia of cochlear hair cells and cooperates with CDC42 to regulate F-actin polymerization and cell protrusion formation in cultured COS-7 cells. In the present work, Fchsd2 knockout mice were established to investigate the role of FCHSD2 in hearing. Our data show that stereocilia maintenance is severely affected in cochlear hair cells of Fchsd2 knockout mice, which leads to progressive hearing loss. Moreover, Fchsd2 knockout mice show increased acoustic vulnerability. Noise exposure causes robust stereocilia degeneration as well as enhanced hearing threshold elevation in Fchsd2 knockout mice. Lastly, Fchsd2/Cdc42 double knockout mice show more severe stereocilia deficits and hearing loss, suggesting that FCHSD2 and CDC42 cooperatively regulate stereocilia maintenance.
Assuntos
Proteínas de Transporte , Perda Auditiva , Proteínas de Membrana , Estereocílios , Animais , Camundongos , Actinas/metabolismo , Proteínas de Transporte/metabolismo , Células Ciliadas Auditivas/metabolismo , Perda Auditiva/metabolismo , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estereocílios/metabolismoRESUMO
Rampant dendrite growth, electrode passivation and severe corrosion originate from the uncontrolled ions migration behavior of Zn2+ , SO4 2- , and H+ , which are largely compromising the aqueous zinc ion batteries (AZIBs) performance. Exploring the ultimate strategy to eliminate all the Zn anode issues is challenging but urgent at present. Herein, a fluorinated separator interface (PVDF@GF) is constructed simply by grafting the polyvinylidene difluoride (PVDF) on the GF surface to realize high-performance AZIBs. Experimental and theoretical studies reveal that the strong interaction between CâF bonds in the PVDF and Zn2+ ions enables evenly redistributed Zn2+ ions concentration at the electrode interface and accelerates the Zn transportation kinetics, leading to homogeneous and fast Zn deposition. Furthermore, the electronegative separator interface can spontaneously repel the SO4 2- and anchor H+ ions to alleviate the passivation and corrosion. Accordingly, the Zn|Zn symmetric cell with PVDF@GF harvests a superior cycling stability of 500 h at 10 mAh cm-2 , and the Zn|VOX full cell delivers 76.8% capacity retention after 1000 cycles at 2 A g-1 . This work offers an all-round solution and provides new insights for the design of advanced separators with ionic sieve function toward stable and reversible Zn metal anode chemistry.
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A novel Gram-stain-negative, curved rod-shaped, motile and chitin-degrading strain, designated CD1T, was isolated from crawfish pond sediment in Caidian District (30° 58' N 114° 03' E), Wuhan City, Hubei Province, PR China. Growth of this strain was observed at 15-40°C (optimum between 28 and 30â°C), at pH 7.0-9.0 (optimum between pH 7.0 and 8.0) and with 0-1â% (w/v) NaCl (optimum at 0â%). With respect to the 16S rRNA gene sequences, strain CD1T had the highest similarity (96.91-97.25â%) to four type strains of the genera 'Chitinolyticbacter' and Chitiniphilus within the family Chitinibacteraceae. The phylogenetic trees based on genome sequences and 16S rRNA gene sequences indicated that strain CD1T was close to members of these two genera, in particular to the genus Chitiniphilus. The genomic DNA G+C content of strain CD1T was 64.8 mol%. The average nucleotide identity and the Genome-to-Genome Distance Calculator results showed low relatedness (below 95 and 70â%, respectively) between strain CD1T and the closely related type strains. Ubiquinone-8 was the predominant quinone. The major cellular fatty acids were C10â:â0, C16â:â0, summed feature 3 (C16â:â1 ω7c and/or C16â:â1 ω6c) and summed feature 8 (C18â:â1 ω7c and/or C18â:â1 ω6c). The polar lipid profile was composed of a mixture of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unidentified lipids, two unidentified phospholipids, two unidentified aminolipids and an unidentified aminoglycolipid. On the basis of the evidences presented in this study, strain CD1T represents a novel species of the genus Chitiniphilus, for which the name Chitiniphilus purpureus sp. nov. is proposed, with strain CD1T (=CCTCC AB 2022395T=KCTC 92850T) as the type strain.
Assuntos
Betaproteobacteria , Quitina , Filogenia , Lagoas , RNA Ribossômico 16S/genética , Composição de Bases , Ácidos Graxos/química , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , BactériasRESUMO
INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a nonspecific chronic inflammatory lung disease with no known cure. Codonopsis Radix (CR) has been shown to exhibit anti-inflammatory and antioxidant effects. Therefore, this study aimed to investigate the potential anti-inflammatory effects of different CR varieties on COPD mice. METHODS: Sixty male-specified pathogen-free grade C57BL/6J mice were randomly divided into 6 groups, 10 mice in each group. The COPD mice model was induced by cigarette smoke extract combined with lipopolysaccharide, and the mice in each group were given corresponding drugs. Lung function was assessed in all mice. Lung tissues were stained with hematoxylin-eosin, Masson, and periodic acid-Schiff stains, and serum levels of interleukin (IL)-8 and tumor necrosis factor (TNF)-α were detected using an ELISA. Further, serum and lung tissue levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were detected by colorimetric assay. Network pharmacology and molecular docking were used to predict signaling pathways, which were validated by Western blot analysis. RESULTS: Compared with the COPD group, the mice in each dosing group of CR exhibited significant reductions in serum IL-8 and TNF-α levels, serum and lung tissue MDA levels, and pathological lung tissue damage, alongside elevations in lung function and SOD levels (p < 0.01). Western blot analysis also indicated significant downregulation of p-p65/p65 and p-IκB-α/IκB-α protein expression, alongside significant upregulation of Nrf2 protein expression in the lung tissues of mice treated with CR (p < 0.01). CONCLUSION: In summary, CR effectively enhances lung function, minimizes lung tissue damage, and inhibits inflammation and oxidative stress in mice with COPD. Additionally, these findings suggest that inhibition of the Nrf2/NF-κB axis may be a key mechanism of action of CR in the alleviation of COPD.
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The emerging outbreak of monkeypox is closely associated with the viral infection and spreading, threatening global public health. Virus-induced cell migration facilitates viral transmission. However, the mechanism underlying this type of cell migration remains unclear. Here we investigate the motility of cells infected by vaccinia virus (VACV), a close relative of monkeypox, through combining multi-omics analyses and high-resolution live-cell imaging. We find that, upon VACV infection, the epithelial cells undergo epithelial-mesenchymal transition-like transformation, during which they lose intercellular junctions and acquire the migratory capacity to promote viral spreading. After transformation, VACV-hijacked RhoA signaling significantly alters cellular morphology and rearranges the actin cytoskeleton involving the depolymerization of robust actin stress fibers, leading-edge protrusion formation, and the rear-edge recontraction, which coordinates VACV-induced cell migration. Our study reveals how poxviruses alter the epithelial phenotype and regulate RhoA signaling to induce fast migration, providing a unique perspective to understand the pathogenesis of poxviruses.
Assuntos
Mpox , Vaccinia virus , Humanos , Movimento Celular , Surtos de Doenças , Células EpiteliaisRESUMO
Hydroquinine-6'-boric acid was first synthesized via a palladium-catalyzed borylation/silica gel promoted hydrolysis sequence of hydroquinine-derived triflate and bis(pinacolato)diboron. The newly designed chiral building block was subjected to the Suzuki-Miyaura cross-coupling reaction, Petasis reaction, and selenylation reaction, respectively, and all these reactions worked well to afford the corresponding 6'-functionalized hydroquinines with satisfactory results, demonstrating its extraordinary application potency.
RESUMO
In China, Codonopsis Radix (CR) is frequently consumed both as food and medicine. Here, a comprehensive strategy based on fingerprinting and chemometric approaches was created to explore the influence of origins, storage time and kneading processing on the quality of CR. Firstly, high-performance liquid chromatography with diode array detection was used to obtain the fingerprints of 35 batches of CR from six different origins and 33 batches of CR from varying storage times or kneading procedures. Secondly, chemometric methods including similarity analysis (SA), principal component analysis (PCA), hierarchical clustering analysis (HCA), and two-way orthogonal partial least square with discriminant analysis (O2PLS-DA) were used to evaluate the differences of chemical components in CR so as to identify its source and reflect its quality. Moreover, 13 and 16 major compounds were identified as marker compounds for the discrimination of CR from different origins, storage time and kneading processing, respectively. Furthermore, the relative content of the marker components and the exact content of Lobetyolin were measured, indicating that the contents of these components vary significantly between various CR samples. Meanwhile, the chemical components of CR were identified using Mass spectrometry. According to the findings of our investigation, the quality of CR from Gansu was the best, followed by Shanxi and then Sichuan. The quality of CR from Chongqing and Guizhou was poor. At the same time, the quality of CR was the best when it was kneaded and stored for 0 years, indicating that the traditional kneading process of CR is of great significance. Conclusively, HPLC fingerprint in conjunction with chemical pattern recognition and component content determination can be employed to differentiate the raw materials of different CR samples. Additionally, it is also a reliable, comprehensive and prospective method for quality control and evaluation of CR.
Assuntos
Codonopsis , Medicamentos de Ervas Chinesas , Quimiometria , Análise por Conglomerados , Análise Discriminante , Espectrometria de Massas , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Análise de Componente PrincipalRESUMO
Inducing immune tolerance through repeated administration of self-antigens is a promising strategy for treating rheumatoid arthritis (RA), and current research indicates that coadministration of immunomodulators can further orchestrate the tolerogenic response. However, most of the clinical trials based on tolerance induction have negligible therapeutic effects. Peripheral lymphoid organs play critical roles in immunotherapy. Here, we design an engineered nanoemulsion for targeted codelivery of self-antigens and an immunomodulator to ectopic lymphoid structures (ELSs) in inflamed joints of RA. Namely, a citrullinated multiepitope self-antigen (CitP) and rapamycin are incorporated into the nanoemulsions (NEs@CitP/Rapa), which are fabricated by a facial method using commercialized pharmaceutical excipients. After intravenous administration, the nanoemulsion shows satisfactory accumulation in the inflamed paws and provides enhanced anti-inflammatory effect in various experimental murine models of RA. Our study provides a promising targeting strategy to induce immune tolerance for the treatment of RA.
Assuntos
Artrite Reumatoide , Autoanticorpos , Animais , Artrite Reumatoide/tratamento farmacológico , Tolerância Imunológica , CamundongosRESUMO
Photodynamic therapy (PDT) is a promising noninvasive medical technology that has been approved for the treatment of a variety of diseases, including bacterial and fungal infections, skin diseases, and several types of cancer. In recent decades, many photosensitizers have been developed and applied in PDT. However, PDT is still limited by light penetration depth, although many near-infrared photosensitizers have emerged. The chemiluminescence-mediated PDT (CL-PDT) system has recently received attention because it does not require an external light source to achieve targeted PDT. This review focuses on the rational design of organic CL-PDT systems. Specifically, PDT types, light wavelength, the chemiluminescence concept and principle, and the design of CL-PDT systems are introduced. Furthermore, chemiluminescent fraction examples, strategies for combining chemiluminescence with PDT, and current cellular and animal applications are highlighted. Finally, the current challenges and possible solutions to CL-PDT systems are discussed.
Assuntos
Neoplasias , Fotoquimioterapia , Animais , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Luminescência , Neoplasias/tratamento farmacológicoRESUMO
Hypochlorous acid (HOCl) is a reactive substance that reacts with most biomolecules and is essential in physiological and pathological processes. Abnormally elevated HOCl levels may cause inflammation and other disease responses. To further understand its key role in inflammation, HOCl must be detected in situ. Here, we designed a hydroxytricyanopyrrole-based small-molecule fluorescent probe (HTCP-NTC) to monitor and identify trace amounts of HOCl in biological systems. In the presence of HOCl, HTCP-NTC released hydroxyl groups that emit strong fluorescence covering a wide wavelength range from the visible to near-infrared region owing to the resumption of the intramolecular charge transfer process. Additionally, HTCP-NTC demonstrated a 202-fold fluorescence enhancement accompanied by a large Stokes shift and a low detection limit (21.7 nM). Furthermore, HTCP-NTC provided a rapid response to HOCl within 18 s, allowing real-time monitoring of intracellular HOCl. HTCP-NTC exhibited rapid kinetics and biocompatibility, allowing effective monitoring of the exogenous and endogenous HOCl fluctuations in living cells. Finally, based on fluorescence imaging, HTCP-NTC is a potential method for understanding the relationship between inflammation and HOCl.
Assuntos
Corantes Fluorescentes , Ácido Hipocloroso , Humanos , Imagem Óptica , InflamaçãoRESUMO
Using biomass-derived solvents in various organic reactions is challenging for the fine chemicals industry. We herein report a Pd/C catalyzed Suzuki-Miyaura reaction in water extract of suaeda salsa (WES) without using external phosphine ligand, base, and organic solvent. The cross-coupling reactions were carried out in a basic WES medium with a broad substrate scope and wide functional group tolerance. Furthermore, the high purity of solid biaryl products can be obtained by column chromatography or filtration.
Assuntos
Chenopodiaceae , Paládio , Catálise , Ligantes , Paládio/química , Solventes , Água/químicaRESUMO
BACKGROUND: Upper urinary tract urothelial carcinoma (UTUC) with multiple pathological types is extremely rare in the clinic, but the recurrence rate and mortality these patients are high. At present, there is no standard treatment for such cases. CASE PRESENTATION: We reported a case of ureteral urothelial carcinoma with squamous cell carcinoma and sarcomatoid carcinoma differentiation and rapid ileal metastasis and reviewed the literature related to different pathological types of upper urinary tract tumours to explore the diagnosis, treatment and prognosis characteristics of the disease, enhance our understanding of its clinical manifestations and history of evolution and provide guidance for avoiding missed diagnosis and misdiagnosis. CONCLUSION: There is no standard treatment for urinary malignant tumours with multiple pathological types; radical surgery is considered a suitable choice. Chemotherapy, targeted drug therapy and immunotherapy may be beneficial to the survival of patients. In short, these patients have a high risk of recurrence and metastasis and a poor prognosis.
Assuntos
Carcinoma de Células Escamosas , Carcinoma de Células de Transição , Neoplasias Ureterais , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Carcinoma de Células de Transição/patologia , Carcinoma de Células de Transição/terapia , Diferenciação Celular , Humanos , Neoplasias Ureterais/patologia , Neoplasias Ureterais/terapiaRESUMO
Objective: To assess the feasibility and validity of the establishment of a modified channel for extraperitoneal robot-assisted laparoscopic radical prostatectomy (RARP) through single incision. METHODS: From November 2020 to January 2021, 35 cases of localized PCa were treated by extraperitoneal RARP through single incision in our center. All the operations were performed by the same surgeon, none via the multichannel port for the establishment of the channel. We recorded and analyzed the intra- and postoperative parameters, operation cost, complications, pathological findings and follow-up data. RESULTS: All the operations were successfully completed, without conversion to open surgery or additional channels, or serious postoperative complications, the time for establishing the extraperitoneal space averaging 25.4 (20.0ï¼45.0) min, the operation time 67.3 (35.0ï¼125.0) min, intraoperative blood loss 75.5 (60.0ï¼150.0) ml, time to first postoperative anal exhaust 26 (8ï¼48) h, and postoperative hospital stay 7.89 (7ï¼10) d. Postoperative pathology showed adenocarcinoma in all the cases, with Gleason score (GS) 3+3 in 9 (25.7%), GS 3+4 in 9 (25.7%), GS 4+3 in 8 (22.9%), and GS ≥ 8 in 9 (25.7%) of the cases, 23 (65.7%) in the Assuntos
Laparoscopia
, Procedimentos Cirúrgicos Robóticos
, Robótica
, Perda Sanguínea Cirúrgica
, Humanos
, Masculino
, Prostatectomia
RESUMO
Stimulator of interferon genes (STING) is critical for cytosolic DNA-triggered innate immunity. STING is modified by several types of polyubiquitin chains. Here, we report that the deubiquitinase CYLD sustains STING signaling by stabilizing the STING protein. CYLD deficiency promoted the K48-linked polyubiquitination and degradation of STING, attenuating the induction of IRF3-responsive genes after HSV-1 infection or the transfection of DNA ligands. Additionally, CYLD knockout mice were more susceptible to HSV-1 infection than their wild-type (WT) littermates. Mechanistically, STING translocated from the ER to the Golgi upon HSV-1 stimulation; CYLD partially accumulated with STING and interacted selectively with K48-linked polyubiquitin chains on STING, specifically removing the K48-linked polyubiquitin chains from STING and ultimately boosting the innate antiviral response. Our study reveals that CYLD is a novel checkpoint in the cGAS-STING signaling pathway and sheds new light on the dynamic regulation of STING activity by ubiquitination.
Assuntos
Enzima Desubiquitinante CYLD/metabolismo , Proteínas de Membrana/metabolismo , Animais , Antivirais/metabolismo , Cisteína Endopeptidases/metabolismo , Complexo de Golgi/metabolismo , Células HEK293 , Células HeLa , Herpesvirus Humano 1/metabolismo , Humanos , Imunidade Inata , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Poliubiquitina/genética , Transdução de Sinais , UbiquitinaçãoRESUMO
Germinal centers (GCs), which are the site of antibody diversification and affinity maturation, are vitally important for humoral immunity. GC B cell proliferation is essentially for these processes by providing enough templates for somatic hypermutation (SHM) and serving as a critical mechanism of positive selection. In the current study, we found a significant reduction of GC response in the spleens of GC B cell specific PHF14 knockout (PHF14GCB KO) mice compared with the wild-type control (PHF14GCB WT) when the mice were challenged with SRBCs or lymphocytic choriomeningitis virus. We also demonstrated that PHF14 did not affect the cell survival of GC B cells, but regulated the proliferation of GC B cells. In addition, PHF14 suppressed the expression of Cdkn1a (p21) though regulating the level of H3K4me3 to control the proliferation of GC B cells. Collectively, our data suggest that PHF14 plays an important role in the process of germinal center formation by regulating GC B cell proliferation in spleen.
Assuntos
Linfócitos B/imunologia , Centro Germinativo/metabolismo , Fatores de Transcrição/metabolismo , Animais , Linfócitos B/metabolismo , Proliferação de Células/fisiologia , Sobrevivência Celular/fisiologia , Imunidade Humoral/imunologia , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Baço/imunologia , Fatores de Transcrição/genéticaRESUMO
Nickel-iron oxyhydroxide (Ni1-xFexOOH) is well recognized as the best-performing oxygen evolution reaction (OER) catalyst in alkaline electrolytes, however its analogue cobalt-iron oxyhydroxide (Co1-xFexOOH) is surprisingly less explored despite their structural similarity. Inspired by our recent study on high-performance HER catalyst using the nanostructured CoMoO4â¢nH2O precursor, herein, we report a facile synthesis of Co1-xFexOOH catalyst derived from the same precursor and its excellent electrocatalytic properties towards the OER in alkaline electrolytes. A core-shell structured nanocatalyst consisting of disordered Co1-xFexOOH layer over the surface of crystalline CoMoO4â¢nH2O nanosheets was synthesized using a simple hydrothermal method followed by anodic electrooxidation. Thus-prepared catalyst exhibited extraordinarily high and stable activity towards the OER in alkaline electrolyte, which outperformed most Co-based OER catalysts. Combined with the HER catalyst derived from the same CoMoO4â¢nH2O precursor as the cathode, we further developed and tested a simple water-splitting cell, which significantly surpasses the benchmarking IrO2-Pt/C couple (1.63 V) and requires a voltage of only 1.517 V to afford 10 mA cm-2 in 1.0 M KOH solution. Density functional theory calculations were conducted to gain insight into the Fe-doping induced improvement of OER activity.
RESUMO
BACKGROUND: Cavernous hemangioma, as a rare tumor, is difficult to differentiate from retroperitoneal lymphoma and paraganglioma. They are more difficult to excise completely through open surgery and traditional laparoscopic surgery. The study aimed to evaluate the role of DaVinci surgical system in laparoscopic resection of parapelvic cavernous hemangioma. CASE PRESENTATION: A 46-year-old female, who diagnosed as parapelvic cavernous hemangioma accompanying with thrombosis and calcification, was performed laparoscopic resection using DaVinci surgical system under general anesthesia. The patient well recovered without recurrence or spread of the lesion after operation for 3 months as well as hydronephrosis was significantly relieved. CONCLUSION: Laparoscopic resection of parapelvic cavernous hemangioma under the help of DaVinci surgical system was feasible and safe.
Assuntos
Hemangioma Cavernoso , Laparoscopia , Neoplasias Pélvicas , Neoplasias Retroperitoneais , Procedimentos Cirúrgicos Robóticos , Feminino , Hemangioma Cavernoso/diagnóstico por imagem , Hemangioma Cavernoso/cirurgia , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Neoplasias Pélvicas/diagnóstico por imagem , Neoplasias Pélvicas/cirurgia , Neoplasias Retroperitoneais/diagnóstico por imagem , Neoplasias Retroperitoneais/cirurgia , Tomografia Computadorizada por Raios XRESUMO
The taxonomic position of a novel actinomycete, strain TRM 41337T, isolated from sediment of a salt lake, Xiaoerkule Lake, Xinjiang, China, was determined by a polyphasic approach. Strain TRM 41337T grew optimally at 28 °C and in the presence of 1â% (w/v) NaCl. It grew at up to pH 12. The whole-cell sugars of strain TRM 41337T were ribose and xylose. The diagnostic diamino acid contained ll-diaminopimelic acid. The polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositolmannoside and two other unidentified phospholipids. The predominant menaquinones were MK-9(H8), MK-9, MK-9(H4) and MK-9(H6). The major fatty acids were iso-C16â:â0, anteiso-C15â:â0, anteiso-C17â:â0 and iso-C16â:â1 H. Based on morphological and chemotaxonomic characteristics, the isolate was determined to belong to the genus Streptomyces. The phylogenetic tree based on its nearly complete 16S rRNA gene sequence (1498 nt) with representative strains showed that the strain consistently falls into a distinct phyletic lineage together with Streptomyces barkulensis DSM 42082T (97.48â% similarity) and a subclade consisting of Streptomyces fenghuangensis GIMN 4.003T (97.20â%), Streptomyces macrosporus NBRC 14748T (97.14â%) and Streptomyces radiopugnans R97T (97.01â%). On the basis of these data, strain TRM 41337T should be designated as a representative of a novel species of the genus Streptomyces, for which the name Streptomyces salilacus sp. nov. is proposed. The type strain is TRM 41337T (=CCTCC AA 2015030T=KCTC 39726T).
Assuntos
Lagos/microbiologia , Filogenia , Salinidade , Streptomyces/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomyces/genética , Streptomyces/isolamento & purificação , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
Synthesis of high-performance and cost-effective catalysts towards the hydrogen evolution reaction (HER) is critical in developing electrochemical water-splitting as a viable energy conversion technique. For non-precious metal Co- and Ni-based catalysts, hydroxides were found to form on the surface of the catalysts under alkaline environments and benefit the catalytic performance, whereas there is limited systematic study on the explicit influence of hydroxides on the electrocatalytic mechanism and performance of these catalysts. Herein, we report a close correlation observed between the amount of the surface hydroxides formed and the resulting electrocatalytic performance of a Co-Mo-O nanocatalyst through careful comprehensive structural and property characterizations. We found that an appropriate amount of hydroxide can be moderated by simply coating the catalyst surface with carbon shells to optimize the catalytic properties. As a result, a carbon-coated Co-Mo-O nanocatalyst was successfully developed and is among the best reported non-precious HER catalysts with a superior electrocatalytic activity and outstanding durability for the HER under alkaline environment. First-principles calculations were further conducted to probe the nature of the active sites and the role of hydroxides in the Co-Mo-O@C/NF catalyst towards the HER.
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Hexavalent chromium (Cr(VI)) is a well-known toxic heavy metal in industrial wastewater, but in situ and real time monitoring cannot be achieved by current methods used during industrial wastewater treatment processes. In this study, a Sediment Microbial Fuel Cell (SMFC) was used as a biosensor for in situ real-time monitoring of Cr(VI), which was the organic substrate is oxidized in the anode and Cr(VI) is reduced at the cathode simultaneously. The pH 6.4 and temperature 25 °C were optimal conditions for the operation. Under the optimal conditions, linearity (R² = 0.9935) of the generated voltage was observed in the Cr(VI) concentration range from 0.2 to 0.7 mg/L. The system showed high specificity for Cr(VI), as other co-existing ions such as Cu2+, Zn2+, and Pb2+ did not interfere with Cr(VI) detection. In addition, when the sediment MFC-based biosensor was applied for measuring Cr(VI) in actual wastewater samples, a low deviation (<8%) was obtained, which indicated its potential as a reliable biosensor device. MiSeq sequencing results showed that electrochemically active bacteria (Geobacter and Pseudomonas) were enriched at least two-fold on the biofilm of the anode in the biosensor as compared to the SMFC without Cr(VI). Cyclic voltammetry curves indicated that a pair of oxidation/reduction peaks appeared at -111 mV and 581 mV, respectively. These results demonstrated that the proposed sediment microbial fuel cell-based biosensor can be applied as an early warning device for real time in situ detection of Cr(VI) in industrial wastewaters.