Japan Atomic Energy Research Institute

About: Japan Atomic Energy Research Institute is a based out in . It is known for research contribution in the topics: Neutron & Irradiation. The organization has 7707 authors who have published 14471 publications receiving 207688 citations.

Polaron Ordering in Low-Doping La 1 − x Sr x MnO 3

Abstract: We have found a polaron ordered phase in low-doping rate ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ ( $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.10$ and 0.15) by neutron scattering study. The onset temperature of the polaron order coincides with the point of resistivity upturn. The periodicity of the hole lattice is commensurate to the structural lattice translation, the unit cell being given by $2a\ifmmode\times\else\texttimes\fi{}2b\ifmmode\times\else\texttimes\fi{}4c$ in cubic perovskite basis. The nominal hole concentration corresponding to this periodicity is $n\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.125$. The polaron lattice seems to have the tendency to lock into this commensurate structure within a finite concentration range around the nominal value of $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.125$.

Auxin and ethylene response interactions during Arabidopsis root hair development dissected by auxin influx modulators.

Abstract: The plant hormones auxin and ethylene have been shown to play important roles during root hair development. However, cross talk between auxin and ethylene makes it difficult to understand the independent role of either hormone. To dissect their respective roles, we examined the effects of two compounds, chromosaponin I (CSI) and 1-naphthoxyacetic acid (1-NOA), on the root hair developmental process in wild-type Arabidopsis, ethylene-insensitive mutant ein2-1, and auxin influx mutants aux1-7, aux1-22, and double mutant aux1-7 ein2. Beta-glucuronidase (GUS) expression analysis in the BA-GUS transgenic line, consisting of auxin-responsive domains of PS-IAA4/5 promoter and GUS reporter, revealed that 1-NOA and CSI act as auxin uptake inhibitors in Arabidopsis roots. The frequency of root hairs in ein2-1 roots was greatly reduced in the presence of CSI or 1-NOA, suggesting that endogenous auxin plays a critical role for the root hair initiation in the absence of an ethylene response. All of these mutants showed a reduction in root hair length, however, the root hair length could be restored with a variable concentration of 1-naphthaleneacetic acid (NAA). NAA (10 nM) restored the root hair length of aux1 mutants to wild-type level, whereas 100 nM NAA was needed for ein2-1 and aux1-7 ein2 mutants. Our results suggest that insensitivity in ethylene response affects the auxin-driven root hair elongation. CSI exhibited a similar effect to 1-NOA, reducing root hair growth and the number of root hair-bearing cells in wild-type and ein2-1 roots, while stimulating these traits in aux1-7and aux1-7ein2 roots, confirming that CSI is a unique modulator of AUX1.

Modulated Structure of the Thermoelectric Compound [Ca2CoO3]0.62CoO2

Abstract: We have determined the crystal structure of the composite crystal [Ca 2 CoO 3 ] 0.62 CoO 2 , known as Ca 3 Co 4 O 9 , by a superspace group approach. Structural parameters were refined with a super...

The Arabidopsis dwarf1 Mutant Is Defective in the Conversion of 24-Methylenecholesterol to Campesterol in Brassinosteroid Biosynthesis

Abstract: Since the isolation and characterization of dwarf1-1 (dwf1-1) from a T-DNA insertion mutant population, phenotypically similar mutants, including deetiolated2 (det2), constitutive photomorphogenesis and dwarfism (cpd), brassinosteroid insensitive1 (bri1), and dwf4, have been reported to be defective in either the biosynthesis or the perception of brassinosteroids. We present further characterization of dwf1-1 and additional dwf1 alleles. Feeding tests with brassinosteroid-biosynthetic intermediates revealed that dwf1 can be rescued by 22α-hydroxycampesterol and downstream intermediates in the brassinosteroid pathway. Analysis of the endogenous levels of brassinosteroid intermediates showed that 24-methylenecholesterol in dwf1 accumulates to 12 times the level of the wild type, whereas the level of campesterol is greatly diminished, indicating that the defective step is in C-24 reduction. Furthermore, the deduced amino acid sequence of DWF1 shows significant similarity to a flavin adenine dinucleotide-binding domain conserved in various oxidoreductases, suggesting an enzymatic role for DWF1. In support of this, 7 of 10 dwf1 mutations directly affected the flavin adenine dinucleotide-binding domain. Our molecular characterization of dwf1 alleles, together with our biochemical data, suggest that the biosynthetic defect in dwf1 results in reduced synthesis of bioactive brassinosteroids, causing dwarfism.