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We have fabricated Bi2212 and Bi2223 bulk samples by shock compaction technique. Seed crystals were added to the starting materials in order to promote crystallization. The grain size of the prepared sample was increased by the addition of seed crystals to the starting material.
Maternal food restriction is known to cause developmental hypertension in offspring. We have previously shown that maternal high-protein diet can reverse fetal programming of hypertension and that branched-chain amino acid (BCAA) concentrations in maternal and fetal plasma were increased by maternal high-protein intake. Then, we hypothesized that isocaloric supplementation with BCAA to a maternal food restriction can reverse the adverse outcome. Pregnant rats were divided into four groups at 7.5 days postcoitum: normally nourished (NN) and 70% undernourished (UN) groups with and without BCAA supplementation (NN–standard diet (SD), NN–BCAA, UN–SD and UN–BCAA groups). Compared with pups in the NN groups, those in the UN–SD group had significantly increased systolic blood pressure (SBP) at 8 and 16 weeks of age (P < 0.05). However, the elevation of SBP was not observed in offspring in the UN–BCAA group. Offspring glomeruli number of the UN groups was significantly lower (P < 0.05) than that of the NN groups, independent of BCAA supplementation. Angiotensin II receptor type 2 (ATR2) mRNA and protein expression in the kidney was significantly augmented in the UN–BCAA group at 30 weeks of age. In conclusion, BCAA supplementation during maternal food restriction prevents developmental hypertension together with increased ATR2 expression in adult offspring kidney.
Autism spectrum disorders (ASD) are life-long neurodevelopmental conditions. The pathophysiology is poorly understood, and the clinical diagnosis can only be made through behavioural assessments. The prevalence of ASD has increased eight-fold over the last three decades. Paralleling this rise, research interest in the disorder has been accumulating, centering on two aspects: risk factors that would explain the increase in prevalence, and precursors that could predict an emergence of ASD prior to 2 years of age. As regard factors responsible for the increased prevalence, an increasing trend of low birthweight (4.2% in 1980 v. 9.6% in 2006 at Japan) and advanced paternal age at birth are potentially implicated. To explore these issues, and to yield an early diagnostic algorithm for ASD, the authors initiated the ongoing Hamamatsu Birth Cohort for Mothers and Children (HBC) in 2007. The strengths of the HBC include frequent, direct face-to-face assessments of all the participating mothers and children during the first 4 years of life (12 assessments); this depth of assessments will disclose subtle changes in the developmental domains of individuals with ASD, which might otherwise be overlooked.
A total of 1200 pregnant women are to be recruited by the end of 2010. Assembled information comprises a range of variables related to the mother’s characteristics and child development. The comprehensiveness of the HBC will provide an informative data source that will elucidate early trajectories of children with ASD in addition to revealing detailed, developmental properties of typically developing children.
An experimental study is carried out to clarify the mechanism of the ozone zero phenomenon. Temporal variations of both the discharge characteristics and the metallic electrode surface in the ozone generator are investigated by the Lissajous figure method and Auger electron spectroscopy (AES), respectively. The AES results suggest that a number of oxygen atoms penetrate into the stainless-steel electrode owing to the exposure to ozone. Such a surface change would result in the temporal variation of the discharge characteristics of the generator.
We study spin injection from an in-plane magnetized Fe thin layer into a GaAs/AlGaAs quantum well (QW) in low magnetic fields of ±0.37 T using oblique Hanle effect. An oblique low magnetic field induces the precession of electron spins in the GaAs QW, allowing us to detect the spin polarization of electrons injected across the Fe/AlGaAs interface. Our analysis of the circular polarization of light emitted in the electron-hole recombination process in the QW gives an estimate of the lower bounds of the spin polarization to be 4.0%. Also, a spin lifetime of 140 psec is obtained in this analysis, indicating that spin depolarization at the Fe/AlGaAs interface is more predominant rather than spin relaxation in the QW region.
Nanoscience: an area that promises new understanding of nature with the aid of rapid progress of nanotechnology. Nanotechnology: the use of nanoscience to build new technologies that will change the world. Nanoscience and Nanotechnology have captured the attention of the public, government, and corporations. How they will influence our lives depend on how we prepare ourselves, and our successors. Here we present a brief outline of the efforts being taken at Osaka University since 2004, in order to prepare our future scientists, engineers, and leaders in the rapidly flourishing trans-/multi-disciplinary field of Nanoscience and Nanotechnology.
Direct characterization of band alignment at chemical bath deposition (CBD)-CdS/Cu0.93 (In1-xGax)Se2 has been carried out by photoemission spectroscopy (PES) and inverse photoemission spectroscopy (IPES). Ar ion beam etching at the condition of the low ion kinetic energy of 350 eV yields a removal of surface contamination as well as successful measurement of the intrinsic properties of each layer and the interfaces. Especially interior regions of the wide gap CIGS layers with a band gap of 1.4 ∼ 1.6 eV were successfully exposed. IPES spectra revealed that the conduction band offset (CBO) at the interface region of the wide gap CIGS with x = 0.60 and 0.75 was negative, where the conduction band minimum of CdS was lower than that of CIGS. It was also observed that the energy spacing between conduction band minimum (CBM) of CdS layer and valence band maximum (VBM) of Cu0.93(In0.25Ga0.75)Se2 layer at interface region was no wider than that of the interface over the Cu0.93(In0.60Ga0.40)Se2 layer.
The regulation of intracellular ascorbic acid (AsA) levels may be under the control of an AsA-specific membrane transporter. The present study investigates AsA uptake and expression of Na-dependent vitamin C transporter (SVCT) mRNA in the mouse osteoblastic cell line, MC3T3-E1. Among eight compounds tested, dexamethasone (Dex) all-trans retinoic acid, transforming growth factor β, prostaglandin E2 and transferrin significantly (P<0·01, P<0·01, P<0·05 and P<0·01 respectively) stimulated the update of AsA into MC3T3-E1 cells. Among these five, Dex was the most active, inducing mSVCT2 mRNA and the uptake of AsA in a time- and concentration-dependant manner. Dex did not induce mSVCT1 mRNA. These results suggest that the Dex-induced stimulation of AsA incorporation into osteoblastic cells is mediated by the induction of mSVCT2. Since Dex reduced alkaline phosphatase activity in MC3T3-E1 cells in our culture conditions, Dex-induced stimulation of AsA incorporation might not be the result of differentiation. Hormone-regulated changes of SVCT expression may have an important role in cell functions.
We report on the spectral and temporal properties of the 50 ms pulsar PSR B0540–69 using ASCA archival data obtained during 1993 to 1995. From the spectral analysis it was found that the spectra of the whole (nebular and pulsed) emission and pulsed emission in the range 1-10 keV can be represented by a single power law of photon index, Γ = 2.00 ± 0.02 and Γpulsed = 1.7 ± 0.3 respectively. The parameters for pulse frequency change during 1993-1995 were obtained using the 9 pulse frequency measurements with ASCA. The parameters derived from the ASCA observations are consistent with the previous measurements, suggesting high stability of this pulsar, ΔΩ/Ω ≲ 0.5 × 10−7 over the past 10 years. These results confirm similarity of this pulsar with the Crab pulsar.
A new structure of triode type field emission displays based on single-walled carbon nanotube emitters is demonstrated. In this structure, gate electrodes are situated under cathode electrodes with an in-between insulating layer, so called under-gate type triode. Electron emission from the carbon nanotube emitters is modulated by changing gate voltages. A threshold voltage is approximately 70 V at the anode bias of 275 V.
In this paper, an analysis of the high voltage induced degradation in top gate amorphous silicon Thin Film Transistors (TFT) will be shown, including the aspect of self-heating. It will be shown through experimental results that the degradation level under high voltages on drain and gate is different for TFT's with different channel lengths. In addition, the temperature distribution over the TFT area for devices with different channel length is simulated. Simulation shows that the peak of temperature distribution is located at the drain/channel edge and that level of thermal heating depends on the channel length.
The field emission properties of hydrogenated amorphous carbon containing up to 29at% nitrogen (a-C:N:H), grown in an integrated distributed electron cyclotron resonance (IDECR) reactor were studied using a sphere-plane geometry. All films were smooth in character and required a high field (20-70V/νm) activation process before emission, which created micron- sized craters in the emission region. Further analysis suggested that the emission originates from activation-created geometrically enhanced areas around the crater region. Upon low-level nitrogen incorporation (N/N+C≤0.2), the field required for activation decreased from 54V/νm to a minimum value of 20V/νm. The turn-on field required for 1νA of current also decreased, reaching a minimum of 11.3V/νm. The decrease in activation and turn-on field was related to the increase in conductivity observed with increasing nitrogen content. At higher nitrogen concentrations, the increase in activation energy and turn on field for emission may be due to changes in overall material structure, as indicated by the decreasing optical gap
Near-infrared (NIR) emission in galaxies is mainly radiated by old population low temperature stars, which construct the basic stellar structure and keep the trails of past galaxy evolution. On the other hand, optical observations show recent star formation activity, especially in spiral galaxies. Therefore multi-color observations from optical to near-infrared wavelengths are very important to understand the past and recent star-formation history. Nearby large galaxies are well studied not only in optical but also in mid- and far-infrared by IRAS, CO and HI radio observations. However, the study in the near-infrared is still limited because large format arrays are not common. Here we show a wide-field, near-infrared imaging of nearby elliptical and spiral galaxies and discuss their star-formation history.
The region south of the reflection nebula NGC1333 in Perseus is an active star forming region including numerous Herbig-Haro objects and at least 5 protostar candidates with molecular outflows and far-infrared emission. It has been actively studied in various wave bands (e.g. Aspin et al 1994 and references therein). We observed this region with ASCA with the primary objective to detect X-rays from the protostars embedded deep in the molecular cloud.
The transition from Al to Cu for advanced ULSI interconnects involves changes in architecture and deposition technique that will influence the microstructure and texture of the metal. Cu interconnects are typically formed within the confines of pre-patterned trenches and vias using an electroplating process with a sputtered Cu conduction layer deposited over a refractory metalbased diffusion barrier layer. In this paper, we focus on the influence of the barrier layer (PVD Ti/TiN, Ta, TaN, CVD TiN) and the effect of a vacuum break between barrier and conduction layer depositions, on the texture of the Cu lines, as examined by X-ray diffraction pole figure analysis.
A preferred (111) orientation was observed for all samples. The samples with no vacuum break between barrier and conduction layer deposition exhibited in plane anisotropy that was particularly pronounced for the Ta and TaN samples compared with the Ti/TiN sample. Focused ion beam images and transmission electron micrographs showed Cu grain size to be on the order of the trench width with a high degree of twinning, and no boundary could be distinguished between the PVD Cu conduction layer and the electroplated Cu.
We have a plan to a radioastronomy mission at the Moon. This is dedicated to the mapping of the CBR anisotropy in order to study the properties of the early Universe, especially galaxy formation. This is a candidate for the Moon mission of NASDA, launched by an HIIA Rocket. The mission carries an 1.5 m (min.) offset parabola antenna with radiation shield to the north polar region of the Moon. This will observe CBR anisotropy at three (min.) frequencies between 30 to 90 GHz. The angular resolution is 9’ at 90 GHz. The telescope will observe the donut-shaped sky between 5 to 30 degree (not fixed) from the Moon celestial north pole. The resultant sensitivity will reach ΔT/T ⋍ 106K in 30’x30’ pixel and ΔT/T ⋍ 105K in 9’x9’ pixel.
We have developed a novel lens-free and mirror-free fiber integrated optical magnetic field sensor. The use of a bent optical fiber and chip optical components allows easy assembly with no alignment. The linearity error and temperature dependence of the sensitivity of this sensor were less than ±1% and +2%, respectively.
Sofue (1996, 1997) presented accurate rotation curves of nearby galaxies, which are almost completely sampled from the inner to outer regions. The conspicuous common feature of the rotation curves is a steep rise at the inner bulge. The rise suggests a compact massive concentration near the nucleus (Sofue 1996). The study of the light distribution at the inner bulge demands accurate surface photometry at near-infrared wavelengths, where dust extinction is much less effective than in the optical. Most of Sofue's samples are nearby large galaxies, so that observations with a wide field view is clue to constructing reliable light distribution models.