The molecular volume of crystals depends on their isotopic masses. This influence originates from the zero-point motion and the resulting small differences in lattice constants. This effect was measured with high precision by using an x-ray standing wave. The standing wave is generated during Bragg reflection and thus is in phase with the planes of the substrate crystal, which is covered with a homoepitaxial film that has a different isotopic composition than the substrate. The positions of the surface planes of the film with respect to the substrate planes are revealed by the photoelectrons excited by the maxima of the standing wave. For germanium-76 on natural germanium(111), a difference in lattice constant of -1.1 x 10(-5) and -2.5 x 10(-5) at 300 and 54 kelvin, respectively, was found. The results are in good agreement with theoretical predictions.
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http://dx.doi.org/10.1126/science.282.5390.930 | DOI Listing |
Ultrasound Med Biol
January 2025
Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong; Biomedical Engineering Programme, The University of Hong Kong, Hong Kong. Electronic address:
Objective: Near-field (NF) clutter filters are critical for unveiling true myocardial structure and dynamics. Randomized singular value decomposition (rSVD) stands out for its proven computational efficiency and robustness. This study investigates the effect of rSVD-based NF clutter filtering on myocardial motion estimation.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Biomedical Engineering, Lund University, Lund SE-223 63, Sweden.
Isolation and characterization of circulating tumor cells (CTCs) present a noninvasive alternative to monitor disease progression in individual patients. However, the heterogeneous lineage specificity of CTCs makes it difficult to isolate and identify possible CTCs by a liquid biopsy. Better label-free methods for the isolation of viable CTCs are needed.
View Article and Find Full Text PDFStretchable microwave absorbers (SMAs) are vital for flexible electronics. Traditional SMAs display unstable tensile properties resulting from inconsistencies between the constrained conductive layer and the flexible dielectric layer. This study introduces an organohydrogel-based stretchable microwave absorber (OSMA) that incorporates an organohydrogel within an island-bridge structure.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2025
Technical University of Munich, TUM School of Natural Sciences, Physics Department E20, Garching 85748, Germany.
Metalloporphyrins on interfaces offer a rich playground for functional materials and hence have been subjected to intense scrutiny over the past decades. As the same porphyrin macrocycle on the same surface may exhibit vastly different physicochemical properties depending on the metal center and its substituents, it is vital to have a thorough structural and chemical characterization of such systems. Here, we explore the distinctions arising from coverage and macrocycle substituents on the closely related ruthenium octaethyl porphyrin and ruthenium tetrabenzo porphyrin on Ag(111).
View Article and Find Full Text PDFAdv Mater
January 2025
State Key Laboratory of Fine Chemicals, Department of Pharmacy, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024, China.
Phytochlorins, a class of plant-derived tetrapyrroles, show great potential as sonosensitizers in sonodynamic therapy (SDT). The development of new phytochlorin-based sonosensitizers has significantly improved SDT, yet the absence of specialized sonodynamic systems limits their clinical translation. Herein, a dedicated ultrasound system along with a detailed step-by-step sonodynamic process from in vitro to in vivo is developed to activate phytochlorin-based sonosensitizers.
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