Scarce and expensive iridium oxide is still the cornerstone catalyst of polymer-electrolyte membrane electrolyzers for green hydrogen production because of its exceptional stability under industrially relevant oxygen evolution reaction (OER) conditions. Earth-abundant transition metal oxides used for this task, however, show poor long-term stability. We demonstrate here the use of nitrogen-doped cobalt oxide as an effective iridium substitute.
View Article and Find Full Text PDFReduction of carbon dioxide (CO) by renewable electricity to produce multicarbon chemicals, such as ethylene (CH), continues to be a challenge because of insufficient Faradaic efficiency, low production rates, and complex mechanistic pathways. Here, we report that the rate-determining steps (RDS) on common copper (Cu) surfaces diverge in CO electroreduction, leading to distinct catalytic performances. Through a combination of experimental and computational studies, we reveal that C─C bond-making is the RDS on Cu(100), whereas the protonation of *CO with adsorbed water becomes rate-limiting on Cu(111) with a higher energy barrier.
View Article and Find Full Text PDFAnion-exchange membrane fuel cells provide the possibility to use platinum group metal-free catalysts, but the anodic hydrogen oxidation reaction (HOR) suffers from sluggish kinetics and its source is still debated. Here, over nickel-tungsten (Ni-W) alloy catalysts, we show that the Ni : W ratio greatly governs the HOR performance in alkaline electrolyte. Experimental and theoretical studies unravel that alloying with W can tune the unpaired electrons in Ni, tailoring the potential of zero charge and the catalytic surface to favor hydroxyl adsorption (OH).
View Article and Find Full Text PDFConverting hydrogen chemical energy into electrical energy by fuel cells offers high efficiencies and environmental advantages, but ultrapure hydrogen (over 99.97%) is required; otherwise, the electrode catalysts, typically platinum on carbon (Pt/C), will be poisoned by impurity gases such as ammonia (NH). Here we demonstrate remarkable NH resistivity over a nickel-molybdenum alloy (MoNi) modulated by chromium (Cr) dopants.
View Article and Find Full Text PDFCorrection for 'Polysaccharides from O.F. Müller inhibit cell proliferation activating MAPK signaling in A549 and H1650 cells' by Juan Juan Yang , , 2021, , 6915-6924, https://doi.
View Article and Find Full Text PDFPlatinum on carbon (Pt/C) catalyst is commercially adopted in fuel cells but it undergoes formidable active-site poisoning by carbon monoxide (CO). In particular, given the sluggish kinetics of hydrogen oxidation reaction (HOR) in anion-exchange membrane fuel cell (AEMFC), the issues of Pt poisoning and slow rate would combine mutually, notably worsening the device performances. Here we overcome these challenges through incorporating cobalt (Co) into molybdenum-nickel alloy (MoNi ), termed Co-MoNi , which not only shows superior HOR activity over the Pt/C catalyst in alkali, but more intriguingly exhibits excellent CO tolerance with only small activity decay after 10 000 cycles in the presence of 500 parts per million (ppm) CO.
View Article and Find Full Text PDFReactive oxygen species (ROS), especially hydrogen peroxide (H2O2), have recently been reported to cause a significant increase in the production and expression of matrix metalloproteinases (MMPs), which are closely correlated with lung cancer metastasis. The aim of the present study is to determine the inhibitory effects of a polysaccharide isolated from Ulva prolifera O.F.
View Article and Find Full Text PDFSortilin is found to regulate proliferation and death of different cells, while its role in regulating keratinocyte proliferation and apoptosis is still unknown. In this study, we found that sortilin levels significantly increased in psoriasis patients, and sortilin suppression eliminated the proliferation of HaCaT cells induced by M5 cocktail solution and enhanced the levels of cleaved caspase 3 protein and the Bax/Bcl-2 ratio; however, levels of p-PI3K and p-AKT were decreased. In addition, sortilin silencing remitted the characteristic changes associated with psoriasis-like skin lesions.
View Article and Find Full Text PDFObjective: To discuss the application of automated DNA image cytometry (ICM) and fluorescence in situ hybridization (FISH) in the diagnosis of urothelial carcinoma of bladder.
Methods: From August 2008 to March 2009, 60 volunteers with informed consent were divided into two groups, 40 patients proven as urothelial carcinoma of bladder by pathology and 20 healthy individuals as control. Urine was collected and tested by cytology, ICM and FISH.
Objective: To investigate the expression of extracellular matrix metalloproteinase induced (EMMPRIN) in the interface tissue, and explore the role of EMMPRIN in the aseptic loosening of prostheses.
Methods: Immunohistochemistry was performed to characterize the EMMPRIN-expressing cells at sites of interface tissue around aseptic loosened hip prostheses in 16 cases. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to study the existence of EMMPRIN mRNA in interface tissue samples.