Bi-self-doped BiVO (Bi-BVO) nanotubes with p-n homojunctions are fabricated via an oxygen-induced strategy. Calcinating the as-spun fibers with abundant oxygen plays a pivotal role in achieving Bi self-doping. Density functional theory calculations and experimental results indicate that Bi self-doping can narrow the band gap of BiVO, which contributes to enhancing light harvesting. Moreover, Bi self-doping endows BiVO with n- and p-type semiconductor characteristics simultaneously, resulting in the construction of p-n homojunctions for retarding rapid electron-hole recombination. Benefiting from these favorable properties, Bi-BVO exhibits a superior photocatalytic performance in contrast to that of pristine BiVO. Furthermore, this is the first report describing the achievement of p-n homojunctions through self-doping, which gives full play to the advantages of self-doping.
to low round-trip efficiency as well as limited capacity. And cathode clogging arising from insulated, insoluble discharge products accumulation blocks the electron transfer and oxygen/Li + diffusion, resulting in a high overpotential for the electrochemical reactions, which will trigger parasitic reactions such as electrolyte oxidation. [5] As cathode corrosion aggravates, the batteries deliver poor cycle stability.Over the past few decades, numerous studies have intensively focused on cathodes and catalysts to address the main challenges in the Li-O 2 batteries. [6][7][8][9][10][11][12] Single atom materials with superior catalytic properties and unique electronic structure are promising electrode materials for Li-O 2 batteries. [13][14][15][16][17][18][19] Single atoms serving as catalytic centers effectively promote the slow kinetic process of lithium oxygen batteries. [20] However, the catalysis of immobile single-atom catalysts is limited only for Li 2 O 2 particles directly deposited on the surface of the catalysts without oxidizing the electronically isolating Li-peroxide layers, which leads to low round-trip efficiency and poor cycle stability. [21][22][23] To address this concern, many attempts have been made to effectively promote the decomposition of Li 2 O 2 . Recently, redox mediators, a kind of liquid catalysts have been developed for facilitating the oxidation of Li 2 O 2 upon charging. [24,25] The redox mediators will first be oxidized in solution phase to form oxidized species during charge process, followed by chemically oxidizing the Li 2 O 2 from the solution side so that the catalytic effect can be exerted on all the Li 2 O 2 that is formed during the ORR process. [26] Lithium bromide (LiBr) was first proposed by Sun and coworkers as a RM in Li-O 2 batteries to reduce the OER overvoltage. [27] Br − can be oxidized upon charging at 3.48 V to Br 3 − and further be oxidized to Br 2 at 4.0 V, both of which can readily react with Li 2 O 2 to form Br − , Li + , and O 2 . [28,29] However, undesirable shuttle phenomenon, that is Br 2 or Br 3 − diffuse to and react with Li anode, resulting in the poor cycle stability and round-trip efficiency. [26] Herein, we report the successful combination of single-atom cobalt anchored in porous N-doped hollow carbon spheres Lithium-oxygen (Li-O 2 ) batteries with ultrahigh theoretical energy density have attracted widespread attention while there are still problems with high overpotential and poor cycle stability. Rational design and application of efficient catalysts to improve the performance of Li-O 2 batteries is of significant importance. In this work, Co single atoms catalysts are successfully combined with redox mediator (lithium bromide [LiBr]) to synergistically catalyze electrochemical reactions in Li-O 2 batteries. Single-atom cobalt anchored in porous N-doped hollow carbon spheres (CoSAs-NHCS) with high specific surface area and high catalytic activity are utilized as cathode material. However, the potential performances of batteries are difficult to...
Bladder cancer is a common tumor type of the urinary system, which has high levels of morbidity and mortality. The first-line treatment is cisplatin-based combination chemotherapy, but a significant proportion of patients relapse due to the development of drug resistance. Therapy-induced senescence can act as a ‘back-up’ response to chemotherapy in cancer types that are resistant to apoptosis-based anticancer therapies. The circadian clock serves an important role in drug resistance and cellular senescence. The aim of the present study was to investigate the regulatory effect of the circadian clock on paclitaxel (PTX)-induced senescence in cisplatin-resistant bladder cancer cells. Cisplatin-resistant bladder cancer cells were established via long-term cisplatin incubation. PTX induced apparent senescence in bladder cancer cells as demonstrated via SA-β-Gal staining, but this was not observed in the cisplatin-resistant cells. The cisplatin-resistant cells entered into a quiescent state with prolonged circadian rhythm under acute PTX stress. It was identified that the circadian protein cryptochrome1 (CRY1) accumulated in these quiescent cisplatin-resistant cells, and that CRY1 knockdown restored PTX-induced senescence. Mechanistically, CRY1 promoted p53 degradation via increasing the binding of p53 with its ubiquitin E3 ligase MDM2 proto-oncogene. These data suggested that the accumulated CRY1 in cisplatin-resistant cells could prevent PTX-induced senescence by promoting p53 degradation.
Genetic polymorphisms of CYP3A5*3 and CYP3A4*18B may be partly responsible in large interindividual variability of cyclosporine and tacrolimus blood levels in Chinese renal transplant patients during the first month after transplantation. A patient carried combined genotype of CYP3A4*1/*1-CYP3A5* 3/*3 might require lower tacrolimus doses to achieve target concentration levels. Genotyping of CYP3A4*18B and CYP3A5*3 before transplantation is of benefit in determining a suitable initial dose for each patient.
Single-atom Co reconstructs the electronic structure of the solid intermediates, benefits the non-locality of electrons and octahedron–tetrahedron fields of solid intermediates, promotes the electron transfer and Li transport of longitudinal deposition.
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