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Perfluorosulfonated ionomers are the most successful ion-exchange membranes at an industrial scale. One recent, cutting-edge application of perfluorosulfonated ionomers is in polymer electrolyte fuel cells (PEFCs). In PEFCs, the ionomers are used as a component of the catalyst layer (CL) in addition to functioning as a proton-exchange membrane. In this study, the microstructures in the CLs of PEFCs were characterized by combined synchrotron X-ray scattering and transmission electron microscopy (TEM) analyses. The CL comprised a catalyst, a support, and an ionomer. Fractal dimensional analysis of the combined ultrasmall- and small-angle X-ray scattering profiles indicated that the carbon-black-supported Pt catalyst (Pt/CB) surface was covered with the ionomer in the CL. Anomalous X-ray scattering revealed that the Pt catalyst nanoparticles on the carbon surfaces were aggregated in the CLs. These findings are consistent with the ionomer/catalyst microstructures and ionomer coverage on the Pt/CB surface obtained from TEM observations.
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http://dx.doi.org/10.3390/membranes11070466 | DOI Listing |
J Phys Chem Lett
September 2025
Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
Water-ion interactions govern the physicochemical properties of aqueous solutions, impacting the structure of the hydrogen bonding network and ion diffusivities. To elucidate these effects under alkaline conditions relevant to diverse application spaces, we examined NaOD-DO solutions using two-dimensional infrared spectroscopy (2D-IR), small-angle X-ray scattering (SAXS), and nuclear magnetic resonance spectroscopy (NMR). Vibrational energy transfer between the donor anion SeCN, used as a 2D-IR probe, and the acceptor anion OD was used to track the average separation distance of ions in the DO solutions, while SAXS and NMR experiments measured the structure of the bulk DO solvent.
View Article and Find Full Text PDFFEBS J
September 2025
Neutron Scattering Division, Oak Ridge National Laboratory, USA.
Serine hydroxymethyltransferase (SHMT) is a critical enzyme in the one-carbon (1C) metabolism pathway catalyzing the reversible conversion of L-Ser into Gly and concurrent transfer of 1C unit to tetrahydrofolate (THF) to give 5,10-methylene-THF (5,10-MTHF), which is used in the downstream syntheses of biomolecules critical for cell proliferation. The cellular 1C metabolism is hijacked by many cancer types to support cancer cell proliferation, making SHMT a promising target for the design and development of novel small-molecule antimetabolite chemotherapies. To advance structure-assisted drug design, knowledge of SHMT catalysis is crucial, but can only be fully realized when the atomic details of each reaction step governed by the acid-base catalysis are elucidated by visualizing active site hydrogen atoms.
View Article and Find Full Text PDFBiophys J
September 2025
Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada; Li Ka Shing Institute of Virology, University of Alberta, Edmonton T6G 2E1, Alberta, Canada; Department of Microbiology, Immunology
The dengue virus (DENV) poses a significant threat to human health, accounting for approximately 400 million infections each year. Its genome features a circular structure that facilitates replication through long-range RNA-RNA interactions, utilizing cyclization sequences located in the untranslated regions (UTRs). To gain new insights into the organization of the DENV genome, we purified the 5' and 3' UTRs of DENV in vitro and examined their structural and binding properties using various biophysical techniques combined with computational methods.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
School of Physics, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece. Electronic address:
Keratins represent an important class of sulfur-rich structural proteins. In this study, the pressure response of α-keratin, extracted from sheep wool, was investigated using Raman spectroscopy up to 4 GPa. A non-polar liquid (a Fluorinert™ FC70/77 mixture) served as the Pressure Transmitting Medium (PTM) in a Diamond Anvil Cell (DAC).
View Article and Find Full Text PDFAdv Mater
September 2025
Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic University, 7098 Liuxian Boulevard, Shenzhen, 518055, China.
Phase segregation remains one of the most critical challenges limiting the performance and long-term operational stability of wide-bandgap perovskite solar cells (PSCs). This issue is especially pronounced in 1.84 eV wide-bandgap (WBG) perovskites, where severe halide phase segregation leads to compositional heterogeneity and accelerated device degradation.
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