In-situ powder neutron diffraction study on the formation process of LaMg2NiH7

The formation process from the intermetallic compound LaMg₂Ni to a complex hydride (deuteride) LaMg₂NiD₇ composed of La³⁺, 2 × Mg²⁺, [NiD₄]^4?, and 3 × D^? was investigated by in-situ powder neutron diffraction under deuterium gas pressure at room temperature. Below 0.001 MPa, small amount of deuterium was initially dissolved in the lattice of LaMg₂Ni forming LaMg₂NiD_0.05 and two new hydride phases (LaMg₂NiD_x1 and LaMg₂NiD_x2) were continuously yielded. Furthermore, LaMg₂NiD_4.6 with NiD_1.9 and NiD_3.3 units and interstitial deuterium atoms was formed prior to appearing of LaMg₂NiD₇. From their Bragg peak positions, the deuterium contents x1, and x2 were inferred as 0.05 < x1 < x2 < 4.6. At approximately 0.001 MPa, LaMg₂NiD₇ started forming. Since the intermediate deuterides had similar metal atomic framework of LaMg₂Ni, we revealed that LaMg₂NiD₇ formation proceeded through multiple deuteride phases with maintaining of the metal atomic framework of LaMg₂Ni.     

Non-four-sided patch expressions with control points

This paper introduces new mathematical expressions which describe surface patches with three, five or six sides. Each side of a patch is given as a space curve expressed in Bézier type of second or third degree. Patch shape is modified predictably by moving its control points in the same way as with a four-sided patch. Distribution of cross tangent vectors along a patch boundary is also expressed in the same form with a few control vectors belonging to the boundary concerned. Therefore it can be connected with its surrounding four-sided patches smoothly. A general method of derivation of these equations is explained for further applications.     

Mechanism of enhancement effect of dendrimer on transdermal drug permeation through polyhydroxyalkanoate matrix

The possible application of polyhydroxyalkanoate (PHA) in transdermal drug delivery systems (TDDSs) for tamsulosin was previously reported. PHAs containing the drugs, ketoprofen, clonidine and tamsulosin showed good adhesiveness to the skin model used, that is, shed snake skin, and dispersed well all model drugs tested. The model drugs hardly permeated through snake skin in solution form. However, these drugs permeated well through snake skin from the PHA matrix. It was previously reported that the addition of a dendrimer, a polymeric permeation enhancer, is effective for the TDDS for tamsulosin to establish an effective clinical TDDS. The effect of dendrimer addition was examined in TDDSs for ketoprofen and clonidine. The dendrimer added did not show an enhancement effect on the TDDSs for the two drugs. To investigate the mechanism of the enhancement effect of a dendrimer on the tamsulosin TDDS, X-ray analyses were performed. With dendrimer addition, drug crystallization in PHA was promoted. The crystal in PHA had highly ordered and changed its space group. These findings are very important for exploiting high-performance PHA-based TDDSs.     

Thermal conductivities of hypostoichiometric (U, Pu, Am)O2−x oxide

The thermal conductivities of (U_0.68Pu_0.30Am_0.02)O_2.00−x solid solutions (x = 0.00-0.08) were studied at temperatures from 900 to 1773 K. The thermal conductivities were obtained from the thermal diffusivities measured by the laser flash method. The thermal conductivities obtained experimentally up to about 1400 K could be expressed by a classical phonon transport model, λ = (A + BT)⁻¹, A(x) = 3.31 × x + 9.92 × 10⁻³ (mK/W) and B(x) = (−6.68 × x + 2.46) × 10⁻⁴ (m/W). The experimental A values showed a good agreement with theoretical predictions, but the experimental B values showed not so good agreement with the theoretical ones in the low O/M ratio region. From the comparison of A and B values obtained in this study with the ones of (U,Pu)O_2−x obtained by Duriez et al. [C. Duriez, J.P. Alessandri, T. Gervais, Y. Philipponneau, J. Nucl. Mater. 277 (2000) 143], the addition of Am into (U, Pu)O_2−x gave no significant effect on the O/M dependency of A and B values.     

Thermal conductivity of (U,Pu,Np)O2 solid solutions

The thermal conductivities of (U_,Pu_,Np)O₂ solid solutions were studied at temperatures from 900 to 1770 K. Thermal conductivities were obtained from the thermal diffusivity measured by the laser flash method. The thermal conductivities obtained below 1400 K were analyzed with the data of (U,Pu,Am)O₂ obtained previously, assuming that the B-value was constant, and could be expressed by a classical phonon transport model, λ = (A + BT)⁻¹, A(z₁, z₂) = 3.583 × 10⁻¹ × z₁ + 6.317 × 10⁻² × z₂ + 1.595 × 10⁻² (m K/W) and B = 2.493 × 10⁻⁴ (m/W), where z₁ and z₂ are the contents of Am- and Np-oxides. It was found that the A-values increased linearly with increasing Np- and Am-oxide contents slightly, and the effect of Np-oxide content on A-values was smaller than that of Am-oxide content. The results obtained from the theoretical calculation based on the classical phonon transport model showed good agreement with the experimental results.     

Effect of Heading Date on the Starch Structure and Grain Yield of Rice Lines with Low Gelatinization Temperature

Early flowering trait is essential for rice cultivars grown at high latitude since delayed flowering leads to seed development at low temperature, which decreases yield. However, early flowering at high temperature promotes the formation of chalky seeds with low apparent amylose content and high starch gelatinization temperature, thus affecting grain quality. Deletion of starch synthase IIa (SSIIa) shows inverse effects of high temperature, and the ss2a mutant shows higher apparent amylose content and lower gelatinization temperature. Heading date 1 (Hd1) is the major regulator of flowering time, and a nonfunctional hd1 allele is required for early flowering. To understand the relationship among heading date, starch properties, and yield, we generated and characterized near-isogenic rice lines with ss2a Hd1, ss2a Hd1 hd1, and ss2a hd1 genotypes. The ss2a Hd1 line showed the highest plant biomass; however, its grain yield varied by year. The ss2a Hd1 hd1 showed higher total grain weight than ss2a hd1. The ss2a hd1 line produced the lowest number of premature seeds and showed higher gelatinization temperature and lower apparent amylose content than ss2a Hd1. These results highlight Hd1 as the candidate gene for developing high-yielding rice cultivars with the desired starch structure.     

Bacterial Alarmone,Guanosine 5′‐Diphosphate 3′‐Diphosphate (ppGpp), Predominantly Binds the β′ Subunit of Plastid‐Encoded Plastid RNA Polymerase in Chloroplasts

It's alarming : Bacterial alarmone guanosine 5′‐diphosphate 3′‐diphosphate (ppGpp), which is a key regulatory molecule that controls the stringent response, also exists in chloroplasts of plant cells. Cross‐linking experiments with 6‐thioguanosine 5′‐diphosphate 3′‐diphosphate (6‐thioppGpp) and chloroplast RNA polymerase indicate that ppGpp binds the β′ subunit of plastid‐encoded plastid RNA polymerase that corresponds to the Escherichia coli β′ subunit.

     

The complete control of murine pregnancy from embryo implantation to parturition

The ovary is the main secretory source of progestin and estrogen and is indispensable to the maintenance of all events of pregnancy in mice. The purpose of this study was to control all processes of pregnancy in mice, from embryo implantation to parturition, without ovaries. The ovaries were removed before embryo implantation, and a single injection of medroxyprogesterone acetate (MPA) was given. Embryo implantation was induced by leukemia inhibitory factor, which can substitute 17β-estradiol (E(2)). Continuous exposure to E(2) was necessary at mid-pregnancy, when placentation was completed. All mice sustained pregnancy without ovaries before parturition, which was initiated by the removal of E(2) and MPA. Murine pregnancy is a complicated process involving embryo implantation, placentation, and parturition. Complete control of pregnancy was achieved with the simple treatment of MPA and E(2) after induction of embryo implantation. Here, time-dependent events in the uterus during pregnancy could be realized without the ovaries, because the initiation of each event could be stringently controlled by hormonal treatments.     

Use of fluorine-doped silicon oxide for temperature compensation of radio frequency surface acoustic wave devices

This paper investigates acoustic properties, including the temperature coefficient of elasticity (TCE), of fluorine-doped silicon oxide (SiOF) films and proposes the application of the films to the temperature compensation of RF SAW devices. From Fourier transform infrared spectroscopy (FT-IR), SiOF films were expected to possess good TCE properties. We fabricated a series of SAW devices using the SiOF-overlay/Cu-grating/LiNbO(3)-substrate structure, and evaluated their performance. The experiments showed that the temperature coefficient of frequency (TCF) increases with the fluorine content r, as we expected from the FT-IR measurement. This means that the Si-O-Si atomic structure measurable by the FT-IR governs the TCE behavior of SiO(2)-based films even when the dopant is added. In comparison with pure SiO(2) with the film thickness h of 0.3 wavelengths (λ), TCF was improved by 7.7 ppm/°C without deterioration of the effective electromechanical coupling factor K2 when r = 3.8 atomic % and h = 0.28λ. Fluorine inclusion did not obviously influence the resonators' Q factors when r < 8.8 atomic %.     

Synthesis of new members of Pb-based 1222 superconductors containing sulfur: (Pb0.75S0.25)Sr2(RE1.6Ce0.4)Cu2O z (RE = Sm,Gd, Dy,and Ho)

We have discovered new members of the Pb-based 1222 layered cuprates containing sulfur of (Pb_0.75S_0.25)Sr₂(RE_1.6Ce_0.4)Cu₂O _z with RE = Sm, Gd, Dy, and Ho. All the samples are of almost-single 1222 phase. From the ρ–T and χ–T measurements, they are found to be superconductors after annealing under 125 atm O₂ atmosphere at 400 °C. Among them, the sample with RE = Gd is found to show superconductivity at the highest temperature of 30 K.