Replica-based freeze-fracture and freeze-etching electron microscopy methods provide surface topography information, particularly suited to studying membrane protein complexes in their native context. The fidelity and resolution of metal replicas is limited by the inherent property of metal atoms to crystallize. To overcome the limitations of metal replicas, we combined amorphous carbon replicas with phase-contrast electron microscopy. Using this approach, tight junction intramembrane fibrils were shown to have a double stranded morphology.
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http://dx.doi.org/10.1038/s42003-019-0319-4 | DOI Listing |
Nanoscale
January 2025
Departments of Chemistry and Physics, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany.
We used a computational method based on (constrained) density functional theory to obtain the photoluminescence spectrum of graphene quantum dots with up to 240 carbon atoms, including the effect of multiphonons. We found that only a few phonon modes couple effectively to the excitons, namely one size- and shape-dependent global mode and two high frequency local modes. The exciton-phonon coupling decreases with increasing size for all structures and has a magnitude in the mid-range, leading to only relatively small multiphonon effects.
View Article and Find Full Text PDFSci Technol Adv Mater
October 2024
Department of Materials, Faculty of Engineering, Kyushu University, Fukuok, Japan.
This review presents computational and machine learning methodologies developed during a 5-year research project on proton-conducting oxides. The main goal was to develop methodologies that could assist in materials discovery or provide new insights into complex proton-conducting oxides. Through these methodologies, three new proton-conducting oxides, including both perovskite and non-perovskites, have been discovered.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
Physical and Chemical Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352.
The formation of mineral-associated organic matter (MAOM) is a key phenomenon that may explain the slow turnover rates of carbon in soil organic matter (SOM). Despite this, important details pertaining to the structure and dynamics of MAOM remain unknown. In the present study, we use replica-exchange molecular dynamics simulations to gain insight into the structure of MAOM on the surface of prototypical phyllosilicate clay and Fe-oxide minerals, montmorillonite and goethite, fine-grained minerals that strongly impact soil carbon dynamics in temperate and tropical regions, respectively.
View Article and Find Full Text PDFNanomaterials (Basel)
October 2024
Dipartimento di Scienze Farmaceutiche, Università di Perugia, Via del Liceo, 1, 06123 Perugia, Italy.
The need to develop synthetic bone substitutes with structures, properties, and functions similar to bone and capable of preventing microbial infections is still an ongoing challenge. This research is focused on the preparation and characterization of three-dimensional porous scaffolds based on hydroxyapatite (HA)-functionalized calcium carbonate loaded with silver nanoparticles and simvastatin (SIMV). The scaffolds were prepared using the foam replica method, with a polyurethane (PU) sponge as a template, followed by successive polymer removal and sintering.
View Article and Find Full Text PDFOpen Res Eur
September 2024
Department of Highway, Ministry of Transportation, Department of Highway, Bangkok, 10400, Thailand.
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