[en] Phytic acid (PA, myo-inositol 1,2,3,4,5,6-hexakisphosphate) is an important anti-nutritional component in cereal and legume grains. PA forms of phosphorus (P) and its salts with micronutrient cations, such as iron and zinc, are indigestible in humans and non-ruminant animals, and hence could affect food/feed nutritional value and cause P pollution of ground water from animal waste. We previously developed a set of low phytic acid (LPA) rice mutants with the aim to increase their nutritional quality. Among them, one line, i.e., Os-lpa -XQZ-1 (hereafter lpa 1-2), was identified to have a mutation allelic to the KBNT lpa 1-1 mutation (hereafter lpa 1-1), which was already delimited to a 47-kb region on chromosome 2. In this study, we searched the candidate gene for these two allelic LPA mutations using T-DNA insertion mutants, mutation detection by CEL I facilitated mismatch cleavage, and gene sequencing. The TIGR locus LOC_Os02g57400 was revealed as the candidate gene hosting these two mutations. Sequence analysis showed that the lpa 1-1 is a single base pair substitution mutation, while lpa 1-2 involves a 1,475-bp fragment deletion. A CAPS marker (LPA1_CAPS) was developed for distinguishing the lpa 1-1 allele from lpa 1-2 and WT alleles, and InDel marker (LPA1_InDel) was developed for differentiating the lpa 1-2 allele from lpa 1-1 and WT ones. Analysis of two populations derived from the two mutants with wild-type varieties confirmed the complete co-segregation of these two markers and LPA phenotype. The LOC_Os02g57400 is predicted to encode, through alternative splicing, four possible proteins that are homologous to the 2-phosphoglycerate kinase reported in hyperthermophilic and thermophilic bacteria. The identification of the LPA gene and development of allele-specific markers are of importance not only for breeding LPA varieties, but also for advancing genetics and genomics of phytic acid biosynthesis in rice and other plant species. (author)

[en] We have successfully synthesized the new single-phase compounds FeSr₂(Ce_3/2Ln_1/2)Cu₂O_10-δ (Ln=Eu, Gd, and Tb). Rietveld refinements of the structure were carried out. This series of compounds have tetragonal structure with space group I4/mmm. Magnetization measurements indicate that the magnetic properties of these compounds depend strongly on the magnetic nature of the rare earth atoms. The Ln=Eu sample exhibits antiferromagnetic order with T_N=25 K, whereas for the Ln=Gd and Tb samples, χ changes with temperature in a Curie-type manner from 5 to 300 K. Resistance measurements indicate that these samples have a semiconductor-like behavior

[en] The crystal structure of the new compound GdSr₂CoCu₂O₇ has been studied by powder X-ray diffraction. This compound crystallizes in space group Ima2 with lattice parameters a=22.7837(4) Angst, b=5.4773(1) Angst and c=5.4383(1) Angst and 4 formula units per unit cell. Like the high-T_c superconductor GdBa₂Cu₃O₇ (Ln-123) the structure of GdSr₂CoCu₂O₇ contains double layers of CuO₅-pyramids separated by trivalent rare earth ions. The rows of CuO₄ square planar groups of Ln-123 superconductors are replaced by rows of corner-sharing CoO₄ tetrahedra. The role of Ba to fill the large voids in Ln-123 is played by Sr in this compound. Magnetization measurements indicate that the magnetic susceptibility χ changes with temperature in a Curie-type manner

[en] The SmBa_2-xSr_xCu₃O_7-δ solid solution was investigated by means of X-ray powder diffraction in combination with the Rietveld refinement method. The Sr-doped Sm123 single phase could be synthesized at 950 deg. C in flowing O₂. The solubility range of the SmBa_2-xSr_xCu₃O_7-δ solid solution is 0.0≤x≤0.9. The structure of SmBa_2-xSr_xCu₃O_7-δ is orthorhombic in the range 0.0≤x<0.5, and tetragonal for 0.5≤x≤0.9. The electrical resistivity and the AC susceptibility as function of the temperature for samples with x=0-0.9 were measured. All the samples with 0.0≤x≤0.9 show superconducting properties (T_C(onset)=93.9-78.9 K). The T_C value of SmBa_2-xSr_xCu₃O_7-δ decreases regularly with increasing Sr content

[en] The PrBa_2-xSr_xCu₃O_7±δ solid solution was investigated by means of X-ray powder diffraction in combination with Rietveld analysis. The Sr-doped Pr123 single phase could be synthesized at 950 deg. C in air. The solubility of PrBa_2-xSr_xCu₃O_7±δ solid solution is 0.2≤x≤0.6. The structure of PrBa_2-xSr_xCu₃O_7±δ is orthorhombic for x=0.2. The structure transforms into tetragonal for 0.3≤x≤0.6. In the PrBa_2-xSr_xCu₃O_7±δ structure, Sr ions can replace Ba ions, the highest value is x=0.6 under our experimental condition. But Sr ions could not replace Pr ions. Furthermore Pr ions could not occupy the sites of Ba ions in the PrBa_2-xSr_xCu₃O_7±δ system. Both ionic radii and chemical properties play an important role in the mutual substitution of Pr, Ba and Sr ions in the Pr123 structure of the PrBa_2-xSr_xCu₃O_7±δ system

[en] The crystal structure of the SmCo_6.7Zr_0.3 and NdCo₄Cu₃ compounds has been investigated by X-ray powder diffraction (XRD). Both compounds crystallize in the hexagonal TbCu₇-type structure. The Rietveld technique has been used to refine the structures. The lattice parameters are a=4.9141(1) A, c=4.0409(1) A for SmCo_6.7Zr_0.3 and a=5.0123(2) A, c=4.0677(2) A for NdCo₄Cu₃. The structure refinement shows that Zr prefers to occupy the 3g site in SmCo_6.7Zr_0.3

[en] We have investigated the structure and magnetic properties of Pr_1-δ(Co,Cu)_5+2δ (0<δ<0.22) compounds with the TbCu₇-type structure, using X-ray powder diffraction and magnetic measurements. The lattice parameters (a and c) of Pr_1-δ(Co,Cu)_5+2δ compounds increase with increasing Cu content since the radius of Cu is a little larger than that of Co. Our experimental results indicate that Cu may stabilize Pr_1-δ(Co,Cu)_5+2δ compounds with the TbCu₇-type structure, but δ is only determined by the temperature. The X-ray patterns of magnetically aligned samples show that the compounds with x=2.0 and 3.0 exhibit easy-plane magnetocrystalline anisotropy. The saturation magnetization and Curie temperature decrease with increasing Cu content

[en] New rare-earth boron-rich compounds with the formula of RE_1-xB₁₂Si_3.3-δ (RE=Y, Gd-Lu) (0≤x≤0.5,δ∼0.3) have been synthesized. They belong to a new type of rhombohedral structure with the space group of R-3m (No. 166) and z=9. The lattice constants were measured from powder XRD data. Crystal structure solved from powder XRD data for Tb_0.68B₁₂Si₃ as a representative has been compared with that of YB_17.6Si_4.6 (or Y_0.68B₁₂Si_3.01), whose structure was solved from single-crystal reflection data. The structure model is confirmed by high-resolution transmission microscope analysis. The vibrational modes of the new crystals were measured by Raman spectroscopy. Temperature dependence of magnetic susceptibility which was measured for RE_1-xB₁₂Si_3.3-δ single crystals by SQUID revealed that they are paramagnetic materials down to 2.0 K

[en] Samples of Ru_1-xCo_xSr₂GdCu₂O₈ (x=0, 0.01, 0.03, and 0.05) were synthesized by solid-state reaction. X-ray diffraction data indicate that all the samples are single phases with Ru-1212 structure. Rietveld refinement was carried out to determine the structure parameters. We present an investigation of the dc magnetic properties. The remnant magnetization at 5 K increases with the increasing of Co content, and the ferromagnetic ordering temperatures are slightly decreased with Co content increase. Substitution of Ru with Co suppresses superconductivity strikingly. The suppression of superconductivity is related to increasing ferromagnetic component in the RuO₂ layers by Co doping and the decrease of the average (Ru,Co)-O bond length of (Ru,Co)O₆ octahedra

[en] The crystal structures of Nd₄Ga₂O₉ and Sm₄Ga₂O₉ compounds synthesized by solid-state reaction at 1400 deg. C are investigated. X-ray diffraction shows that Nd₄Ga₂O₉ and Sm₄Ga₂O₉ are monoclinic system with the space group P2₁/c, and lattice parameters a=7.7656(1) A, b=10.9689(1) A, c=11.4727(1) A, β=109.06(1) deg. for Nd₄Ga₂O₉, and a=7.6613(1) A, b=10.8546(1) A, c=11.4080(1) A, β=108.80(1) deg. for Sm₄Ga₂O₉. The gallium atoms are in the center of distorted oxygen tetrahedra with an average Ga-O bond distance between 1.82 and 1.85 A. The rare earth atoms are sixfold or sevenfold coordinated by oxygen. The oxygen atoms are threefold and fourfold coordinated. The magnetization for these compounds clearly reflects paramagnetism. The magnetic susceptibility χ changes with temperature in a Curie-type manner