Ferroelectric and Magnetic Properties in Room‐Temperature Multiferroic GaxFe2−xO3 Epitaxial Thin Films

GaFeO₃‐type iron oxide is a promising room‐temperature multiferroic material due to its large magnetization. To expand its usability, controlling the ferroelectric and magnetic properties is crucial. In this study, high‐quality Ga_xFe_2–xO₃ (x = 0–1) epitaxial films are fabricated and their properties are systematically investigated. All films exhibit room‐temperature out‐of‐plane ferroelectricity, showing that the coercive electric field (E_c) decreases monotonically with x. Additionally, the films show in‐plane ferrimagnetism with a Curie temperature (T_C) >350 K at x = 0–0.6. The coercive magnetic field (H_c) decreases with x at x ≤ 0.6, but shows a constant value at x > 0.6, whereas the saturated magnetization (M_s) increases with x at x ≤ 0.6, but decreases with x at x > 0.6. X‐ray magnetic circular dichroism reveals that the large magnetization at x = 0.6 is derived from Fe³⁺ (3d⁵) at octahedral sites. The controllable range of the E_c, H_c, and M_s values at room temperature (400–800 kV cm^?1, 1–8 kOe, and 0.2–0.6 µ_B/f.u.) is very wide and differs from those of well‐known multiferroic BiFeO₃. Furthermore, the Ga_xFe_2?xO₃ films exhibit room‐temperature magnetocapacitance effects, indicating that adjusting T_C near room temperature is useful to achieve large room‐temperature magnetocapacitance behavior.     

Changes in the characteristics of CuInGaSe2 solar cells under light irradiation and during recovery: degradation analysis by the feeble light measuring method

Changes in the characteristics of CuInGaSe₂ solar cells in response to light irradiation were investigated. Then these changes, which suggest long-term degradation, were clarified using the measurement technique by feeble light. The thin-film cell of this type is considered to be “ever stable”. A stable result over the short term was also obtained in the light accelerated test of 2-SUN performed in this experiment. On the other hand, it was found that the characteristics measured with feeble light show a remarkable change over time. As a result of measuring at 0.065–105 mW/cm² light intensity, the change rate of cell output power was so intense the measurement light was weak. This finding reflects the increase in an internal defect and suggests a possibility that light irradiation exerts the influence on long-term cell performance. Moreover, by measuring with feeble light, we found that the changed output recovers by reverse voltage application. The phenomenon of recovery up on comparatively low reverse voltage can be considered as an application for maintaining stability.     

Atomistic origin of high-quality “novel SiON gate dielectrics”

We have investigated the effect of the oxygen incorporation into SiN films by the first principles calculations. The calculated results show that the oxygen incorporation tends to generate defect states in SiN band gap by forming dangling bonds and floating bonds of Si. Based on the calculated results, it is also indicated that the high quality SiON film can be fabricated by suppressing the incorporation of O atoms into the SiN film, reproducing the reported experiments.     

Three-dimensional reconstruction of goblet cells in the rabbit conjunctivum

Goblet cells in the rabbit bulbar conjunctivum were not real "goblet," but were variable in shape. The diversity of the morphology became evident by means of computer-aided three-dimensional reconstruction. All of the cells reconstructed (N = 5) were in touch with the basal lamina, and were open to the epithelial surface. Their cytoplasm was filled with secretory granules (about 71% of the cellular volume, in average), while the nucleus occupied only 5.3%.     

THERMOGENIC PETROLEUM POTENTIAL OF THE NANKAI SUBDUCTION ZONE,OFFSHORE SW JAPAN

In the Kumano forearc basin, offshore SW Japan, the potential occurrence of hydrocarbons has been inferred from both geophysical surveys which point to the presence of natural gas hydrates, and geochemical analyses of gas samples recovered from boreholes and submarine mud volcanoes. The forearc basin is located in the inner part of the Nankai Trough where the Philippine Sea plate is subducting northwards beneath SW Japan. The basin succession unconformably overlies a deformed accretionary prism complex. Hydrocarbons with both microbial and thermogenic origins have been recorded in the Kumano Basin, but the thermogenic petroleum potential is poorly constrained because the regional‐scale geological architecture of the Nankai subduction zone is not well understood. In this paper, the regional‐scale petroleum potential of the Nankai Trough is investigated based on the geological interpretation of new seismic reflection images. The images were derived from legacy seismic survey data using advanced processing techniques such as reverse time migration, which make use of both primary and multiple reflections in wide‐angle seismic data collected with ocean‐bottom seismographs. In the study area, a seaward‐dipping reflector was identified which terminates at the plate boundary décollement and which is interpreted as part of the boundary between previously‐identified older (>14 Ma) and younger (<6 Ma) accretionary prisms. A triangle body at the base of the younger accretionary prism is interpreted to consist of underthrusted sediments including thick hemipelagic mudstones with source rock potential which were scraped off the down‐going oceanic plate. These tentatively identified, deeply‐buried mudstones may have the potential to generate thermogenic hydrocarbons which may then migrate upwards along dipping carrier beds or faults and fractures to the unconformity at the base of the Kumano forearc basin succession. The presence of hydrocarbons in the accretionary prism may be inferred from positive amplitude anomalies which have been identified in the reprocessed multi‐channel seismic data. The new reflection interpretations therefore allow the potential for thermogenic petroleum to be proposed in the study area. The hydrocarbon potential at this subduction margin may therefore rely not only on shallow microbial methane, but may also involve deeper, thermogenic petroleum generated within the underlying accretionary prism.     

Porcine enamel matrix derivative enhances the formation of reparative dentine and dentine bridges during wound healing of amputated rat molars

We examined the biological effects of porcine enamel matrix derivative (EMD; Emdogain) on the formation of reparative dentine and dentine bridges in rat molars after pulp amputation. The pulp chambers of upper molars of Wistar rats were perforated and the amputated pulp surfaces were directly capped with either EMD or its carrier propylene glycol alginate (PGA) as control. The cavities were then restored with glass-ionomer cement. On post-amputation days 4-30, the dissected maxillae were examined by light and electron microscopy. In PGA-capped pulp, reparative dentine had been formed over the dentine walls under the prepared cavity on day 7 post-amputation and its thickness extended until day 30. On day 30, as well as reparative dentine formation, diffuse calcification had occurred beneath the amputated wound surfaces. Dentine bridge formation under the amputated coronal pulp surface was observed in 18.2% of amputated pulp on day 30. In EMD-capped pulp, reparative dentine had already been formed by odontoblast-like cells over the dentine walls, already on day 4 post-amputation, and its thickness extended until day 30. The Ca and P weight % and Ca/P ratio of reparative dentine matrix were similar to those of pre-existing dentine matrix, and these values were not different between PGA and EMD-capped pulp. Dentine bridge formation was observed in 27.3% of EMD-capped pulp on day 30. Our results suggest that EMD enhances the formation of both reparative dentine and dentine bridges during wound healing of amputated rat molar pulp.     

Osteoclast differentiation at growth plate cartilage-trabecular bone junction in newborn rat femur

Using 3-day-old newborn rats, we examined the differentiation processes of osteoclasts associated with the destruction of the femoral growth plate cartilage and primary trabecular bone. In the growth plate cartilage, thin mineralized areas were detected solely in the longitudinal septal cartilage matrix in the hypertrophic zone, but the transverse septal cartilage matrix between adjacent chondrocytic lacunae within a row of chondrocytes remained unmineralized. The longitudinal septal cartilage between adjacent rows of chondrocytes appeared to persist, forming the walls of opened lacunar canals. Consistent with the removal of the transverse septal cartilage matrix, the longitudinal canals of opened chondrocytic lacunae were deeply invaded by capillary vessels, mononuclear cells and multinucleated pre-osteoclasts lacking a ruffled border. CD34-positive endothelial cells of capillary vessels deeply penetrated into the transverse septal cartilage matrix facing the medullary cavity and the opened chondrocytic lacunae. ED1-positive monocytes/macrophages were distributed at the chondro-osseous junction, but they were distant from the erosive front of the transverse septa. Tartrate-resistant acid phosphatase-positive multinucleated pre-osteoclasts lacking a ruffled border and differentiated osteoclasts with a ruffled border were localized mainly at two locations: the chondro-osseous junction and the growth front of primary bone trabeculae. Osteoclasts were located on the type-I collagen-positive bone trabeculae close to the growth plate, but they appeared to be distant from the type-II collagen-positive cartilage matrix. Even within opened chondrocytic lacunae, when osteoclasts were distant from the cartilage and bone matrix, they lacked polarized cytoplasmic organization and a ruffled border. The osteoclasts located in the remaining septal cartilage also exhibited neither a ruffled border nor a clear zone. Osteoclasts with a prominent ruffled border and clear zone were located in bone matrix covering the remaining septal cartilage. These results suggest that osteoclasts require hydroxyapatite crystals and bone matrix constituents for ruffled border formation and are not involved in resorption of the unmineralized transverse and mineralized longitudinal septal cartilage without covering bone matrix at the chondro-osseous junction.     

Synthesis and properties of N-alkyl-N′-aryl-3,4:9,10-perylenebis(dicarboximide)

N′-Alkyl-N′-aryl-3,4:9,10-perylenebis(dicarboximide) (alkyl = isobutyl, pentyl, hexyl, octyl, etc.; aryl = phenyl, p-tolyl, p-methoxyphenyl, etc.) were prepared by the condensation of N-alkyl-3,4:9,10-perylene-tetracarboxylic monoanhydride monoimide with arylamines (aniline, p-toluidine, p-anisidine, o-phenylenediamine, etc.). The properties of these derivatives as pigments were tested, and also the thermal stability of 3,4:9,10-perylenebis(dicarboximide) derivatives was measured.     

Immunomagnetic flow cytometric detection of staphylococcal enterotoxin B in raw and dry milk

A rapid and sensitive method for detection of staphylococcal enterotoxin B (SEB) in raw and dry milk samples with the use of antibody-based immunomagnetic separation (IMS) in conjunction with flow cytometry (FCM) was developed. Sheep anti-SEB immunoglobulin G (IgG) was immobilized on Dynabeads M-280. The SEB initially binds to the capturing antibody, which is bound on the magnetic beads. The rabbit anti-SEB IgG binds to the captured toxin and is further labeled with a Cy5-labeled goat anti-rabbit IgG antibody. The percentage of the beads that were fluorescent was measured by FCM. FCM was carried out for 1 min, and the data obtained were expressed as histograms for particle size (forward light scatter) and histograms for fluorescence intensity. A peak corresponding to the magnetic beads was clearly distinguished from a peak derived from contaminating particles in the sample solution. In the absence of SEB, about 10% of the beads emitted fluorescence. The percentage of fluorescent beads and the fluorescence intensity increased with increasing SEB concentrations. For this IMS-FCM assay, the lower limits of detection for SEB were estimated to be 0.01 and 0.25 ng/ml for buffer and milk samples, respectively.