Electron dense markers of a size suitable for transmission electron microscopy and scanning electron microscopy have been prepared with gold granules labeled with a monolayer of specific macromolecules. The optimum conditions for preparing the markers have been ascertained. The method is simple, rapid and seems to be general since gold granules have been labeled with polysaccharides and proteins. As homogeneous populations of gold granules having different sizes can be prepared, the method is also suitable for double marking experiments. The gold technique is illustrated by the localization of polysaccharides and glycoproteins on yeast cell walls and erythrocyte membranes by transmission electron microscopy and on yeast cells and intact erythrocytes by scanning electron microscopy. Good spatial resolution of the marker was achieved in all cases. The method is also suitable for marking thin sections. Spectrophotometric measurements were used to determine the number of gold granules adsorbed per cell.
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http://dx.doi.org/10.1177/25.4.323352 | DOI Listing |
Ultramicroscopy
January 2025
National Centre for Nano Fabrication and Characterization (DTU Nanolab), Technical University of Denmark (DTU), Kgs. Lyngby, Denmark. Electronic address:
Advances in analytical scanning transmission electron microscopy (STEM) and in microelectronic mechanical systems (MEMS) based microheaters have enabled in-situ materials' characterization at the nanometer scale at elevated temperature. In addition to resolving the structural information at elevated temperatures, detailed knowledge of the local temperature distribution inside the sample is essential to reveal thermally induced phenomena and processes. Here, we investigate the accuracy of plasmon energy expansion thermometry (PEET) as a method to map the local temperature in a tungsten (W) lamella in a range between room temperature and 700 °C.
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January 2025
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Controlling charge transport at the interfaces of nanostructures is crucial for their successful use in optoelectronic and solar energy applications. Mixed-dimensional heterostructures based on single-walled carbon nanotubes (SWCNTs) and transition metal dichalcogenides (TMDCs) have demonstrated exceptionally long-lived charge-separated states. However, the factors that control the charge transport at these interfaces remain unclear.
View Article and Find Full Text PDFBraz Oral Res
January 2025
Universidade de São Paulo - USP, School of Dentistry, Department of Operative Dentistry, São Paulo, SP, Brazil.
The aim of this study was to assess the effect of a chlorhexidine digluconate solution (CHX) applied as an antiproteolytic agent for controlling erosive tooth wear or as part of the adhesive treatment on long-term bond strength to eroded dentin. Dentin specimens were abraded with a 600-grit silicon carbide (SiC) paper for 1 min (sound dentin - S), subsequently treated with 2% CHX for 1 min (with excess removed, followed by a 6-hour rest), and eroded by exposure to Coca-Cola for 5 min, three times a day, for 5 days (CHX-treated and eroded dentin - CHXE), or only eroded (eroded dentin - E). The specimens were acid-etched (15 s), rinsed (30 s), dried (15 s), and rehydrated with 1.
View Article and Find Full Text PDFSci Adv
January 2025
Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
Several human disorders, including Alzheimer's disease (AD), are characterized by the aberrant formation of amyloid fibrils. In many cases, the amyloid core is flanked by disordered regions, known as fuzzy coat. The structural properties of fuzzy coats, and their interactions with their environments, however, have not been fully described to date.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
Heterogeneous catalysts have emerged as a potential key for closing the carbon cycle by converting carbon dioxide (CO) into value-added chemicals. In this work, we report a highly active and stable ceria (CeO)-based electronically tuned trimetallic catalyst for CO to CO conversion. A unique distribution of electron density between the defective ceria support and the trimetallic nanoparticles (of Ni, Cu, Zn) was established by creating the strong metal support interaction (SMSI) between them.
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