Publications by authors named "H Kikunaga"

Thorium-229 (Th) possesses an optical nuclear transition between the ground state (Th) and low-lying isomer (Th). A nuclear clock based on this nuclear-transition frequency is expected to surpass existing atomic clocks owing to its insusceptibility to surrounding fields. In contrast to other charge states, triply charged Th (Th) is the most suitable for highly accurate nuclear clocks because it has closed electronic transitions that enable laser cooling, laser-induced fluorescence detection and state preparation of ions.

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Currently, targeted alpha therapy (TAT) is a new therapy involving the administration of a therapeutic drug that combines a substance of α-emitting nuclides that kill cancer cells and a drug that selectively accumulates in cancer cells. It is known to be effective against cancers that are difficult to treat with existing methods, such as cancer cells that are widely spread throughout the whole body, and there are high expectations for its early clinical implementation. The nuclides for TAT, including Tb, At, Bi, Pb (for Bi), Ra, Ac, Th, and U, are known.

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Activity of Ac was measured by the digital anti-coincidence spectroscopy technique using a 4πα-γ detector configuration, composed of a sandwich type 4π plastic scintillator and Ge detectors. Ultrathin plastic scintillators were used for selective detection of α-particles emitted from Ac and its progenies, and the α-counting efficiencies of a 4π plastic scintillation detector for individual nuclides in the decay chain were determined as well. A list-mode multichannel analyzer was employed to record coincidence/anti-coincidence events for off-line analyses.

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Potassium (K) is a major essential element in plant cells, and KUP/HAK/KT-type K transporters participate in the absorption of K into roots and in the long-distance transport to above-ground parts. In Arabidopsis thaliana, KUP9 is involved in the transport of K and Cs in roots. In this study, we investigated KUP9 function in relation to the K status of the plant.

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Salinity stress can greatly reduce seed production because plants are especially sensitive to salt during their reproductive stage. Here, we show that the sodium ion transporter AtHKT1;1 is specifically expressed around the phloem and xylem of the stamen in to prevent a marked decrease in seed production caused by salt stress. The stamens of AtHKT1;1 mutant under salt stress overaccumulate Na, limiting their elongation and resulting in male sterility.

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