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Single-phased, single-oriented thin films of Mn-doped ZnAs-based diluted magnetic semiconductor (DMS) Ba1-xKx(Zn1-yMny)2As2 (x = 0.03, 0.08; y = 0.15) have been deposited on Si, SrTiO3, LaAlO3, (La,Sr)(Al,Ta)O3, and MgAl2O4 substrates, respectively. Utilizing a combined synthesis and characterization system excluding the air and further optimizing the deposition parameters, high-quality thin films could be obtained and be measured showing that they can keep inactive-in-air up to more than 90 hours characterized by electrical transport measurements. In comparison with films of x = 0.03 which possess relatively higher resistivity, weaker magnetic performances, and larger energy gap, thin films of x = 0.08 show better electrical and magnetic performances. Strong magnetic anisotropy was found in films of x = 0.08 grown on (La,Sr)(Al,Ta)O3 substrate with their magnetic polarization aligned almost solely on the film growth direction. [ABSTRACT FROM AUTHOR]

Complex conductivity of FeSe0.5Te0.5 superconducting films has been investigated using backward-wave-oscillator spectroscopy in the terahertz frequency range. The normal state conductivity corresponds well to the lowfrequency limit of a Drude metal. In the superconducting state, the real part of the complex conductivity is not completely suppressed, indicating the existence of a strongly anisotropic gap. Weak features in the conductivity are consistent with the superconducting gap value close to 12 cm-1(1.5 meV). The experimental results are discussed within the framework of a two-gap model based on the s± symmetry of the order parameter. [ABSTRACT FROM AUTHOR]

High quality epitaxial thin films of FeSe1-xTe_x (x=0–1) have been successfully fabricated. Their superconducting transition temperatures are around 8–13 K. Microwave properties of a film (x=0.7) was studied by a sapphire dielectric cavity at 9.315 GHz. The cavity, which has a quality factor of 45000 in room temperature with TE011-mode, is specially designed for the measurement of small samples with the sapphire cylinder having a small hole in the center. Thin film samples with dimension of 1–2 mm can be put in the middle of the hole, supported by a very thin sapphire rod. The cavity is sealed in a vacuum chamber soaked in the liquid ^4He and the temperature of the thin sapphire rod (hence the sample) can be controlled from 1.6 K to 60 K with a stability about \pm1 mK. Temperature dependence of transmission response and Q-factors were measured by a network analyser (Agilent N5230C). The results showed a clear signature of multi-gap superconductivity. No evidences of existence of node in the energy gap were found as the normalized change in the surface reactance and the corresponding normalized change in the in-plane penetration depth have flat dependence at low temperatures. [ABSTRACT FROM AUTHOR]

Single-phased, single-oriented thin films of Mn-doped ZnAs-based diluted magnetic semiconductor (DMS) Ba1-xKx(Zn1-yMny)2As2 (x = 0.03, 0.08; y = 0.15) have been deposited on Si, SrTiO3, LaAlO3, (La,Sr)(Al,Ta)O3, and MgAl2O4 substrates, respectively. Utilizing a combined synthesis and characterization system excluding the air and further optimizing the deposition parameters, high-quality thin films could be obtained and be measured showing that they can keep inactive-in-air up to more than 90 hours characterized by electrical transport measurements. In comparison with films of x = 0.03 which possess relatively higher resistivity, weaker magnetic performances, and larger energy gap, thin films of x = 0.08 show better electrical and magnetic performances. Strong magnetic anisotropy was found in films of x = 0.08 grown on (La,Sr)(Al,Ta)O3 substrate with their magnetic polarization aligned almost solely on the film growth direction. [ABSTRACT FROM AUTHOR]

HLA-DR is one of the markers associated with hematopoietic cell differentiation, since expression of this molecule is modulated throughout hematopoiesis. We have previously described and cloned the gene encoding factor IK, which inhibits both interferon gamma (IFN-gamma)-induced and constitutive HLA-DR expression. The current study demonstrates that IK gene transcripts are present in CD34+ cells purified from human umbilical cord blood. IK expression increased and was therefore inversely correlated with the gradual loss of HLA-DR during growth factor-induced CD34+ cell proliferation and differentiation. To study the possible role of IK in hematopoiesis, antisense probes were used. IK expression was specifically inhibited by an antisense oligodeoxynucleotide containing two phosphorothioate internucleotide linkages at each of the 3' and 5' ends and corresponding to the initiation site of IK mRNA. A control oligonucleotide was also tested in parallel. A specific decrease of IK transcripts was correlated with an increase of HLA-DR antigen expression level. In colony-forming assays, IK antisense oligonucleotide inhibited colony formation by multilineage early erythroid and granulomonocytic CD34+ progenitors. The mean colony size was decreased 70% by IK antisense oligonucleotide in comparison to controls. These results provide evidence that the IK molecule participates in the regulation of HLA-DR expression on hematopoietic cells and plays a role in growth factor-dependent CD34+ cell proliferation and differentiation by modulating HLA-DR expression.

Angle-resolved light scattering (ARLS) is used to estimate the root-mean-square (rms) slopes of rough surfaces having a well-defined lay, and the effect on slope measurements caused by changing the angles of incidence and scattering is investigated. The ARLS patterns are taken with the Detector Array for Laser Light Angular Scattering (Dallas) research instrument, and the rms slopes are obtained from the angular widths of these patterns. In general, it was found that the angular width, and thus the estimated rms slope, is surprisingly insensitive to relatively large changes in both the incident and scattering angles of light. These results are independent of surface material and are valid for both sinusoidal and random rough surfaces with lay. The principles, experiments, analyses, and conclusions involved in using ARLS to estimate rms surface slopes are described.