Differences in body size and shape can cause large variances in the in vivo results of neutron activation analysis. To introduce corrections for body size for the delayed gamma neutron activation facility at Brookhaven National Laboratory, "reference man"-sized and "reference woman"-sized phantoms were constructed. Simulation results using the Monte Carlo Neutron and Photon Transport code also provided correction factors for people of different sizes. For individuals with a body mass index (BMI = weight (kg)/height (m)2) between 20 and 30, no correction was required. At BMIs greater than 30, the effects of neutron attenuation were significant and a correction factor of CF = -0.0192 x BMI + 1.5635 can be applied.
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http://dx.doi.org/10.1111/j.1749-6632.2000.tb06438.x | DOI Listing |
Life Sci Space Res (Amst)
February 2025
National Research Council of Italy, Rome, Italy. Electronic address:
The paper presents the variations of space radiation (primary and secondary galactic cosmic rays (GCR) absorbed dose rate in silicon and flux) measured during the first-ever commercial suborbital flight of the Virgin Galactic (VG) SpaceShipTwo Unity on 29 June 2023. A Portable Dosimeter-Spectrometer Liulin-CNR-VG is used. It is developed in the Space Research and Technology Institute, Bulgarian Academy of Sciences (SRTI-BAS) under a scientific contract with National Research Council of Italy (CNR), Italy.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
CuO octahedra usually show elongated distortion, leading to active orbitals and planar exchange interactions, while compressed CuO octahedra with active orbitals and unidirectional exchange interactions are exceptionally rare. Here, we design and synthesize a new frustrated antiferromagnet CaCuFeO through a high-pressure and high-temperature approach, in which robust compressed CuO octahedra are realized, separating the FeO sheets that comprise zigzag spin ladders. Magnetic susceptibility and specific heat measurements exhibit a long-range antiferromagnetic order below the Néel temperature of 165 K, which is further confirmed by neutron diffraction.
View Article and Find Full Text PDFBioorg Med Chem Lett
January 2025
Department of Infectious Diseases, Kumamoto University School of Medicine, Kumamoto 860-8556, Japan; Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo 162-8655, Japan; Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
We describe here the design, synthesis, and X-ray structural studies of a new class of HIV-1 protease inhibitors containing 8-oxabicyclo[3.2.1]octanol-derived P2 ligands.
View Article and Find Full Text PDFAppl Radiat Isot
January 2025
Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan; Nuclear Science and Technology Development Center, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan. Electronic address:
In clinical boron neutron capture therapy (BNCT), the distribution of dose to a heterogeneous medium that is predicted by a treatment planning system (TPS) should be experimentally validated. A head phantom specifically developed for this purpose is described and demonstrated herein. The cylindrical phantom exhibits distinct regions made from four materials (polymethyl methacrylate, calcium phosphate, air, and boric acid) to approximate a head structure with explicitly defined skin, skull, and brain tissue with a cavity and tumor within.
View Article and Find Full Text PDFScience
January 2025
Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford, UK.
The distribution of substitutional aluminum (Al) atoms in zeolites affects molecular adsorbate geometry, catalytic activity, and shape and size selectivity. Accurately determining Al positions has been challenging. We used synchrotron resonant soft x-ray diffraction (RSXRD) at multiple energies near the Al K-edge combined with molecular adsorption techniques to precisely locate "single Al" and "Al pairs" in a commercial H-ZSM-5 zeolite.
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