We measure the J = 1 to J = 2 fine structure interval in the ( 3)2P state of helium to be 2 291 175.9(1.0) kHz. We use laser excitation of an atomic beam along with an integrated electro-optic modulator technique to obtain this result. The result is consistent (2.9+/-3.2 kHz) with what could be considered an earlier version of this experiment but is not in good agreement ( 20+/-5 kHz and 22+/-8 kHz) with the two other precision determinations of this interval. The current theoretical prediction lies between and overlaps the experiments.
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http://dx.doi.org/10.1103/PhysRevLett.84.4321 | DOI Listing |
Environ Sci Technol
January 2025
Geomicrobiology, Department of Geosciences, University of Tübingen, Tübingen 72076, Germany.
Defects are common features in hematite that arise from deviations from the perfect mineral crystal structure. Vacancy defects have been shown to significantly enhance arsenate (As) immobilization by hematite. However, the contributions from vacancy defects on different exposed facets of hematite have not been fully quantified.
View Article and Find Full Text PDFActa Crystallogr A Found Adv
March 2025
Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-11 Mustuno, Atsuta-ku, Nagoya, 456-8587, Japan.
Due to the short de Broglie wavelength of electrons compared with X-rays, the curvature of their Ewald sphere is low, and individual electron diffraction patterns are nearly flat in reciprocal space. As a result, a reliable unit-cell determination from a set of randomly oriented electron diffraction patterns, an essential step in serial electron diffraction, becomes a non-trivial task. Here we describe an algorithm for unit-cell determination from a set of independent electron diffraction patterns, as implemented in the program PIEP (Program for Interpreting Electron diffraction Patterns), written in the early 1990s.
View Article and Find Full Text PDFFront Plant Sci
January 2025
Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan.
Insular species are usually endemic and prone to long-term population reduction, low genetic diversity, and inbreeding depression, which results in difficulties in species conservation. The situation is even more challenging for the glacial relict species whose habitats are usually fragmented in the mountainous regions. is an endangered and endemic relict tree species in Taiwan.
View Article and Find Full Text PDFJACS Au
January 2025
UCIBIO-Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal.
The mucin -glycan sialyl Tn antigen (sTn, Neu5Acα2-6GalNAcα1--Ser/Thr) is an antigen associated with different types of cancers, often linked with a higher risk of metastasis and poor prognosis. Despite efforts to develop anti-sTn antibodies with high specificity for diagnostics and immunotherapy, challenges in eliciting high-affinity antibodies for glycan structures have limited their effectiveness, leading to low titers and short protection durations. Experimental structural insights into anti-sTn antibody specificity are lacking, hindering their optimization for cancer cell recognition.
View Article and Find Full Text PDFRSC Adv
January 2025
Shaanxi Province Key Laboratory of Catalytic, School of Chemical and Environmental Science, Shaanxi University of Technology Hanzhong 723001 P. R. China
Asymmetric catalytic reactions are essential for synthesizing chiral drugs and fine chemicals, with their stereoselectivity influenced significantly by interactions between catalysts and substrates. Ketone catalysts have garnered considerable attention in the realm of asymmetric photoreactions because of their highly controllable structures, ease of availability, and environmental friendliness. This review highlights the application of various reported ketone catalysts in a range of asymmetric photoreactions, including [2 + 2] photocycloaddition, photoderacemization, photochemical rearrangement, asymmetric electrophilic amination, and asymmetric alkylation of aldehydes.
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