We present a proof-of-concept attesting the feasability to obtain orientation maps of polycrystalline materials within a conventional Scanning Electron Microscope (SEM) using a standard goniometer and Back Scattered Electron (BSE) detector. The described method is based on the analysis of the contrast variation of grains due to the channeling of incident electrons on a rotating sample. On each pixel of the map, experimental intensity profiles as a function of the rotation angle are obtained and compared with simulated ones to retrieve the orientation. From first results on aluminum polycrystals, the angular resolution is estimated to be better than one degree.
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http://dx.doi.org/10.1016/j.ultramic.2017.12.019 | DOI Listing |
Microsc Microanal
January 2025
Université de Lorraine, CNRS, Arts et Métiers, LEM3, Metz 57070, France.
Characterizing threading dislocations (TDs) in gallium nitride (GaN) semiconductors is crucial for ensuring the reliability of semiconductor devices. The current research addresses this issue by combining two techniques using a scanning electron microscope, namely electron channeling contrast imaging (ECCI) and high-resolution electron backscattered diffraction (HR-EBSD). It is a comparative study of these techniques to underscore how they perform in the evaluation of TD densities in GaN epitaxial layers.
View Article and Find Full Text PDFMicroscopy (Oxf)
January 2025
Department of Materials Physics, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.
The distribution of dopants in host crystals significantly influences the chemical and electronic properties of materials. Therefore, determining this distribution is crucial for optimizing material performance. The previously developed statistical ALCHEMI (St-ALCHEMI), an extension of the atom-location by channeling-enhanced microanalysis (ALCHEMI) technique, utilizes variations in electron channeling based on the beam direction relative to the crystal orientation.
View Article and Find Full Text PDFNat Struct Mol Biol
January 2025
Key Laboratory of Multiple Organ Failure (Ministry of Education), Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Fatty acids (FAs) are essential building blocks for all the domains of life, of which bacterial de novo synthesis, called type II FA synthesis (FAS II), is energetically expensive. The recycling of exogenous FAs (eFAs) partially relieves the FAS II demand and, therefore, compromises the efficacy of FAS II-directed antimicrobials. The versatile acyl-acyl carrier protein (ACP) synthetase, AasS, enables bacterial channeling of diverse eFA nutrients through holo-ACP, an activated form of ACP.
View Article and Find Full Text PDFSmall
January 2025
Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, No. 174 Shazheng Road, Chongqing, 400044, China.
Direct electrochemical detection of miRNA biomarkers in tumor tissue interstitial fluid (TIF) holds great promise for adjuvant therapy for tumors in the perioperative period, yet is limited by background interference and weak signal. Herein, a wash-free and separation-free miRNA biosensor based on photoexcited electro-driven reactive oxygen channeling analysis (LEOCA) is developed to solve the high-fidelity detection in physiological samples. In the presence of miRNA, nanoacceptors (ultrasmall-size polydopamine, uPDA) are responsively assembled on the surface of nanodonors (zirconium metal-organic framework, ZrMOF) to form core-satellite aggregates.
View Article and Find Full Text PDFJ Virol
December 2024
Université Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.
Bacteriophages are viruses infecting bacteria. The vast majority of them bear a tail, allowing host recognition, cell wall perforation, and DNA injection into the host cytoplasm. Using electron cryo-microscopy (cryo-EM) and single particle analysis, we determined the organization of the tail proximal extremity of siphophage T5 that possesses a long flexible tail and solved the structure of its tail terminator protein p142 (TrP).
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