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Nuclear Reaction Analysis
Published in Zeev B. Alfassi, Max Peisach, Elemental Analysis by Particle Accelerators, 2020
and C48a(p, n)S48cQ=−510keVyield neutrons at proton energies below the threshold of the corresponding reactions on the two most abundant calcium isotopes 40Ca and 42Ca. At a proton bombarding energy of 4.5 MeV, the highest energy of neutrons from 43Ca, 43Ca(n0) is 1478 keV, while calcium- 48 yields several neutron groups above this energy (Figure 6). It is thus possible to integrate the counts from the first five most abundant reaction groups of 48Ca to give a measure of the content of this isotope, 40 free from any contribution from 43Ca. In the energy region of the 43Ca(n0) and 43Ca(nx) neutron groups, the yield of neutrons from 48Ca is comparatively small and can be calculated from the yield of the high-energy neutrons, to obtain a neutron count representative of calcium-43.
Toxicological effects of hydroxychloroquine sulfate and chloroquine diphosphate substances on the early-life stages of fish in the COVID-19 pandemic context
Published in Journal of Environmental Science and Health, Part A, 2023
Isabella Ferreira Silva, Keiza Priscila Enes, Gustavo Machado Rocha, Fernando Pilla Varotti, Leandro Augusto Barbosa, Ralph Gruppi Thomé, Hélio Batista dos Santos
Newly hatched zebrafish larvae exposed to HCQ were the same length as those in the control group (Fig. 3e). On the other hand, zebrafish larvae exposed to all CQ treatments showed a significant decrease in total length compared to the control group (Fig. 3f). Spinal cord defects, tail curvature, and short body were frequently observed in the groups treated with HCQ and CQ (Fig. 3h). The abnormal spinal cord and tail are teratogenic effects frequently reported in fish embryo acute toxicity assays after exposure to medicines as nimesulide, ibuprofen, ketoprofen, naproxen, and HCQ.[9,20,30,32,39] Although these malformations might not lead to death, they can cause an erratic swimming, which facilitates predation, contributing to an ecological imbalance in nature. The spinal cord defects can be associated with a deficiency or imbalance of phosphorus and calcium,[48] and are probably associated with cardiovascular dysfunction in embryos/larvae after exposure to xenobiotics, preventing the absorption of nutrients for organogenesis.
Passive personal air sampling of dust in a working environment—A pilot study
Published in Journal of Occupational and Environmental Hygiene, 2019
Mariam Shirdel, Ingvar A. Bergdahl, Britt M. Andersson, Håkan Wingfors, Johan N. Sommar, Ingrid E. Liljelind
Microscopic imaging with manual inspection of each image (around 200 images per UNC sampler, examples presented in Figure 3) showed almost exclusively particles reminiscent of gravel, expressing crystal habit (hexagonal, cubic shaped, etc.). Particles of fibrous character were extremely rare, and on all the samplers combined (each sampler containing a minimum of 13,548 particles) there was a total of only 20 particles differing from the rest, having fibrous character. There were no other differing particles. The EDS analysis showed that 100% of the examined areas contained silicon, 94% aluminium, 91% iron, 79% potassium, 75% sulphur, 73% calcium, 48% magnesium, 42% copper, 42% titanium, and 30% sodium, indicating a mineral origin for the particles. For examples of images from the EDS elemental mapping, see the supplementary material (Figures S1 and S2).
Recent activities in the field of separation science and technology of radioactive elements
Published in Journal of Nuclear Science and Technology, 2019
Akihiro Uehara, Koichiro Takao
Isotope separation is also performed by chemical exchange processes based on the isotope fractionations between two isotopic compounds. To develop the calcium-48 48Ca enrichment process, a feasibility study on a band chromatography was made using 9 M HCl solution and crown ether resin synthesized in porous silica beads [10]. As another method for isotope separation, the feasibility of separating radioactive Cs isotopes using the effects of light-induced drift (LID), which is the massive flow of particles caused by the difference between the collision frequencies of the buffer particles in the optically connected ground and excited states were investigated [11].