Prediction markers for respiratory distress syndrome: evaluation of the stable microbubble test, surfactant protein-A and hepatocyte growth factor levels in amniotic fluid.

Surfactant treatment in infants with respiratory distress syndrome (RDS) has decreased neonatal mortality. With the advent of this therapy, it has become important to predict accurately the fetal lung maturity of a fetus before delivery. We evaluated the stable microbubble test (SMT), surfactant protein-A (SP-A) and hepatocyte growth factor (HGF) in amniotic fluid as predicting markers for RDS. Of 55 amniotic fluid samples obtained by amniocentesis from women less than 37 weeks pregnant, the SMT values were as follows: sensitivity 76.5%, specificity 84.2%, positive predictive value 68.4%, negative predictive value 88.9% and overall accuracy 81.8%. For SP-A, the values were 88.2%, 65.8%, 53.6%, 92.6% and 72.7%, respectively. If we used both SMT and SP-A, we could diagnose with 100% accuracy that a case with measurements of SMT &#62; or = 2 and SP-A &#62; or = 420 ng/ml would not complicate with RDS (24/24). However, the RDS diagnostic accuracy of HGF does not equal to those of SMT and SP-A levels. We concluded that the rapidity, simplicity and reliability of SMT was very useful during 24-36 weeks of gestation as a bedside procedure to predict fetuses likely to develop RDS. We also noted the additive effect of SP-A in improving the accuracy of lung maturity diagnosis.</p

Annealing of an AlN buffer layer in N2-CO for growth of a high-quality AlN film on sapphire

The annealing of an AlN buffer layer in a carbon-saturated N2–CO gas on a sapphire substrate was investigated. The crystal quality of the buffer layer was significantly improved by annealing at 1650–1700 °C. An AlN buffer layer with a thickness of 300 nm was grown by metalorganic vapor phase epitaxy (MOVPE), and was annealed at 1700 °C for 1 h. We fabricated a 2-µm-thick AlN layer on the annealed AlN buffer layer by MOVPE. The full widths at half maximum of the (0002)- and ($10\bar{1}2$)-plane X-ray rocking curves were 16 and 154 arcsec, respectively, and the threading dislocation density was 4.7 × 108 cm−2

High-field transport properties of a P-doped BaFe₂As₂ film on technical substrate

High temperature (high-Tc) superconductors like cuprates have superior critical current properties in magnetic fields over other superconductors. However, superconducting wires for high-field-magnet applications are still dominated by low-Tc Nb3Sn due probably to cost and processing issues. The recent discovery of a second class of high-Tc materials, Fe-based superconductors, may provide another option for high-field-magnet wires. In particular, AEFe2As2 (AE: Alkali earth elements, AE-122) is one of the best candidates for high-field-magnet applications because of its high upper critical field, Hc2, moderate Hc2 anisotropy, and intermediate Tc. Here we report on in-field transport properties of P-doped BaFe2As2 (Ba-122) thin films grown on technical substrates by pulsed laser deposition. The P-doped Ba-122 coated conductor exceeds a transport Jc of 105 A/cm2 at 15 T for main crystallographic directions of the applied field, which is favourable for practical applications. Our P-doped Ba-122 coated conductors show a superior in-field Jc over MgB2 and NbTi, and a comparable level to Nb3Sn above 20 T. By analysing the E − J curves for determining Jc, a non-Ohmic linear differential signature is observed at low field due to flux flow along the grain boundaries. However, grain boundaries work as flux pinning centres as demonstrated by the pinning force analysis

Reduction of dislocation density of aluminium nitride buffer layer grown on sapphire substrate

An aluminium nitride (AlN) buffer layer with 200 nm thickness was grown on (0001) sapphire substrate using the metal-organic vapour phase epitaxy (MOVPE) method in a low-pressure furnace, followed by a clean-up treatment of sapphire substrate at 1100°C. Thereafter, the AlN buffer layer was annealed at a high temperature in the range of 1500°C to 1700°C for 2 hours under the atmosphere of N2+CO. The objective of this research is to determine the microstructure changes with different annealing temperatures. Cross-sectional TEM has revealed that, after annealing at 1500°C, two types of defects remained in the AlN buffer layer: inverted cone shape domains and threading dislocations. The former domains were observed in an image taken with diffraction of g=0002, but not in an image with g=1010. The morphology and the diffraction condition for the image contrast strongly, suggesting that the domains are inversion domains. The threading dislocations were invisible in the image taken with the diffraction of g=0002, revealing that they were a-Type dislocations. However, after annealing at 1600oC, the inversion domains coalesced with each other to give a two-layer structure divided by a single inversion domain boundary at the centre of the AlN buffer layer. The density of threading dislocation was roughly estimated to be 5×109 cm-2 after annealing at 1500°C, and to be reduced to 5×108 cm-2 after annealing at 1600°C. These experimental results validate the fact that the annealing temperature around 1600°C is high enough to remove the defects by the diffusion process. Therefore, it was discovered that high temperature annealing is an effective treatment to alter the microstructure of AlN thin films and remove defects by the diffusion process. Annealing at high temperature is recommended to increase the emission efficiency for fabrication of optoelectronic device

Fabrication and characterization of plasmonic band-stop filter using Ag grating

This study proposes a plasmonic band-stop filter with surface plasmon resonance in a doublelayer wire grid structure targeting short-wavelength visible and near-ultraviolet regions for applications in ultraviolet photography. Using Ag and Al, the rigorous coupling wave of analysis method revealed that the maximum absorption was approximately 90% at 450 nm and 375 nm. The experiments using Ag produced similar results in a simulation. These results demonstrate that plasmonic band-stop filters in the visible and near-UV region can be realized at 450 nm and 375 nm using Ag or Al