Hj. Kim

Optical parameters in SnO2 nanocrystalline textured films grown on p-InSb (111) substrates

Abstract Spectroscopic ellipsometry and photoluminescence (PL) measurements on SnO2 nanocrystalline textured films grown on p-InSb (111) substrates by using radio-frequency magnetron sputtering at low temperature were carried out to investigate the dependence of the optical parameters on the SnO2 thin film thickness. As the SnO2 film thickness increases, while the energy gap of the SnO2 film decreases, its refractive index increases. The PL spectra show that the broad peaks corresponding to the donor–acceptor pair transitions are dominant and that the peak positions change with the SnO2 film thickness. These results can help improve understanding for the application of SnO2 nanocrystalline thin films grown on p-InSb (111) substrates in potential optoelectronic devices based on InSb substrates.

Circulating osteoprotegerin levels are elevated and correlated with antiphospholipid antibodies in patients with systemic lupus erythematosus

Patients with antiphospholipid syndrome (APS) have an increased risk for the development of thrombotic complications. Recent studies indicate that osteoprotegerin (OPG) acts as an important molecule in the development of vascular diseases. The aim of the present study was to examine the association between serum OPG levels and APS manifestations in patients with SLE. Seventy-nine patients with SLE and ninety-two healthy controls, matched for age and sex, were included in this study. Serum levels of OPG, monocyte chemoattractant protein(MCP)-1 and soluble E-selectin were determined by ELISA. At the time of serum sampling, various clinical and laboratory parameters were assessed. We found that serum levels of OPG were significantly higher in patients with SLE than in healthy controls (1236 ± 82 vs 967 ± 37 pg/mL, P = 0.003). Particularly, serum OPG levels were significantly higher in SLE patients with APS than those without (1615 ± 191 vs 1171 ± 91 pg/mL, P = 0.006). Serum OPG levels correlated with titres of IgG anti-cardiolipin antibody (P = 0.026) and anti-β2-glycoprotein I antibody (P < 0.001). Moreover, serum OPG also correlated with serum levels of sE-selectin (P = 0.002), which is an endothelial cell activation marker, and MCP-1 (P = 0.003), a well known chemokine implicated in thrombogenesis. Collectively, serum OPG levels were increased in SLE patients with APS and correlated with titres of antiphospholipid antibodies, suggesting that OPG might be linked to the development of APS.

Microstructural and interband transition properties of vertically stacked InAs/GaAs self-assembled quantum dots embedded in modulation-doped heterostructures

The transmission electron microscopy image and selected area electron diffraction pattern showed that self-assembled InAs quantum-dot (QD) arrays embedded in GaAs barriers were periodically inserted in an Al0.25Ga0.75As/GaAs heterostructure. The temperature-dependent photoluminescence spectra of the InAs/GaAs quantum dots embedded in modulation-doped heterostructures showed interband transitions from the first-excited electronic subband to the first-excited heavy-hole subband together with those from the ground subband to the ground heavy-hole band (E1–HH1) while the spectra of the InAs/GaAs QDs alone showed only the peak related to the (E1–HH1) transitions.

Anti-heparan sulfate antibody and functional loss of glomerular heparan sulfate proteoglycans in lupus nephritis:

Background The purpose of this study was to evaluate the features of heparan sulfate proteoglycans (HSPGs) as agrins of the glomerular basement membrane (GBM) and circulating anti–heparan sulfate (HS) antibodies in lupus nephritis, comparing titers among the following groups: lupus nephritis (LN), non-renal lupus, non-lupus nephritis, and healthy controls. Methods The stage of nephritis was determined based on the kidney biopsy. Alcian blue staining and immunohistochemical (IHC) staining for agrin were performed for histological evaluation of GBM HSPGs in normal glomeruli, non-lupus membranous glomerulonephritis (MGN), and lupus MGN. The results were used for measurement of the serum anti-HS antibody titers using an enzyme-linked immunosorbent assay (ELISA) in the following groups: 38 healthy controls, 38 non-lupus nephritis, 37 non-renal lupus, and 38 LN. Results Glomerulus HSPGs were stained bluish-green along the GBM with Alcian blue. However, IHC staining against agrin was almost completely negative in the lupus MGN group compared with the normal and non-lupus MGN groups, which showed brown staining of GBM. A higher level of anti-HS IgG was detected in LN compared with other groups, respectively. Higher titers were associated with the presence of SLE and nephritis. A higher degree of proteinuria normalized to glomerular filtration rate (eGFR) was observed in association with higher anti-HS antibody titers in LN. Conclusion This study demonstrated a functional loss of GBM HSPGs and higher levels of circulating anti-HS antibodies as a characteristic feature of lupus nephritis, suggesting their involvement in the pathogenesis of lupus nephritis and proteinuria.

Microstructural and interband transition studies of multiple stacked layers of Si-doped InAs self-assembled quantum dot arrays inserted into GaAs barriers

Microstructural and optical properties of Si-doped InAs quantum dot (QD) arrays inserted into undoped GaAs barriers have been investigated by using energy dispersive X-ray fluorescence (EDX), transmission electron microscopy (TEM), and photoluminescence (PL) measurements. The EDX pattern, the TEM image, and the selected area electron diffraction pattern showed that self-assembled Si-doped InAs vertically stacked QD arrays were embedded in the GaAs barriers. The temperature-dependent PL spectra showed that the peaks corresponding to the interband transitions of the InAs QDs shifted to the low-energy side with increasing temperature and that the distribution of carriers in the InAs QDs varied with changing temperature. These results indicate that Si-doped InAs QD arrays inserted into GaAs barriers hold promise for potential applications in optoelectronic devices.

Integrating Geographic Information System And Remote Sensing In Predicting Rice Grain Protein

Application of remote sensing and GIS has great potential in crop monitoring and retrospectively can set the strategies and management practices as to maximize yield and grain quality. In this study, UAV remote sensing data were utilized to predict grain protein content. Total images were differentiated into two groups as cloud free and cloud shadowed. On one hand for the cloud free samples, the vegetation index, NDVI derived from the canopy spectral reflectance was significantly correlated to the final grain protein content (R2=0.553, RMSE=0.210%, n=14). On the other hand, for cloud shadowed samples, the result demonstrated that vegetation index, NDVI was significantly correlated to the final grain protein content (R2=0.479, RMSE=0.225%, n=35). Different layers and files were created to manage, store and mapping grain protein using ArcGIS. All test fields at first and then, the NDVI image of each test field was also converted to shape file. Henceforth, the information of each field was displayed using overlap function. Therefore, protein content of rice in each field can be mapping by GIS and possibly forecasted using canopy or images spectral reflectance at grain filling stage.

Microstructural and interfacial properties of the Ru/p-InP(100) heterostructures

Abstract A new approach has been introduced for the fabrication of Ru/p-InP(100) heterostructures with the goal of producing stable Ru contacts and sharp Ru/p-InP heterointerfaces. Atomic force microscopy and X-ray diffraction measurements showed that the Ru film layers grown on InP substrates were polycrystalline thin films with very smooth surfaces. Auger electron spectroscopy and Rutherford backscattering measurements showed that the composition of the as-grown film was Ru and that the Ru/InP interface quality was relatively good. Transmission electron microscopy and selected-area electron-diffraction measurements showed that the grown Ru film was a polycrystalline layer with small grain domains. These results can help improve understanding for the application of Ru/InP heterostructures in high-speed metal–semiconductor field-effect transistors.