Growth of well-aligned ZnO nanorods using auge catalyst by vapor phase transportation.

Well-aligned ZnO nanorods have been achieved using new alloy (AuGe) catalyst. Zn powder was used as a source material and it was transported in a horizontal tube furnace onto an AuGe deposited Si substrates. The structural and optical properties of ZnO nanorods were characterized by scanning electron microscopy, high resolution X-ray diffraction, and photoluminescence. ZnO nanorods grown at 650 degrees C on 53 nm thick AuGe layer show uniform shape with the length of 8 +/- 0.5 microm and the diameter of 150 +/- 5 nm. Also, the tilting angle of ZnO nanorods (+/- 5.5 degrees) is confirmed by HRXRD. High structural quality of the nanorods is conformed by the photoluminescence measurement. All samples show strong UV emission without considerable deep level emission. However, weak deep level emission appears at high (700 degrees C) temperature due to the increase of oxygen desertion.

The shape control of ZnO based nanostructures.

Tetrapod-shape ZnO nanostructures are formed on Si substrates by vapor phase transportation method. The effects of two important growth parameters, growth temperature and VI/II ratio, are investigated. The growth temperature is varied in the range from 600 degrees C to 900 degrees C to control the vapor pressure of group II-element and the formation process of nanostructures. VI/II ratio was changed by adjusting the flux of carrier gas which affects indirectly the supplying rate of group VI-element. From the scanning electron microscopy (SEM), systematic variation of shape including cluster, rod, wire and tetrapod was observed. ZnO tetrapods, formed at 800 degrees C under the carrier gas flux of 0.5 cc/mm2 min, show considerably uniform shape with 100 nm thick and 1-1.5 microm long legs. Also stoichiometric composition (O/Zn - 1) was observed without any second phase structures. While, the decrease of growth temperature and the increase of carrier gas flux, results in the irregular shaped nanostructures with non-stoichiometric composition. The excellent luminescence properties, strong excitonic UV emission at 3.25 eV without deep level emission, indicate that the high crystalline quality tetrapod structures can be formed at the optimized growth conditions.

Electrochemical isothermal-capacitance-transient spectroscopy: a new depth profiling method of deep levels.

The authors report on a new depth profiling method of deep levels, which we call electrochemical isothermal-capacitance-transient spectroscopy (EICTS). This is combined with electrochemical capacitance-voltage using the Schottky barrier of etchable electrolyte and isothermal-capacitance-transient spectroscopy using the capacitance-transient profile at a fixed temperature. We proved its validity by applying to the ZnSe:N epitaxial film of thickness of more than 1000 nm and comparing the characteristics of an obtained deep level with the results measured by conventional deep-level detection techniques. It is expected that EICTS is very effective to assess the deep levels of wide-bandgap semiconductors that suffer from various point defects and their complexes.

Systemic lupus erythematosus with concurrent protein-losing enteropathy and primary sclerosing cholangitis: a unique association.

We describe a 24-year old male patient with systemic lupus erythematosus (SLE) with the gastrointestinal manifestations of protein-losing enteropathy (PLE) and primary sclerosing cholangitis (PSC). He presented with periorbital, scrotal and lower limb oedema. PLE was diagnosed because of hypoalbuminaemia together with an elevation of alpha-1-antitrypsin stool clearance and absence of proteinuria. PSC was diagnosed on the basis of an elevated serum alkaline phosphatase and lymphocytic and fibrous cholangitis. His disease was also complicated by neuropsychiatric lupus and hypogonadism. All the manifestations of SLE resolved with systemic corticosteroids and pulsed cyclophosphamide treatment. This case report documents the unusual association of SLE with PLE and PSC, and this relationship suggests that autoimmunity underlie the pathogenesis of these conditions.

PAH utilization by Pseudomonas rhodesiae KK1 isolated from a former manufactured-gas plant site.

Pseudomonas rhodesiae KK1 was isolated from a former manufactured-gas plant site, due to its ability to grow rapidly in a mixture of polycyclic aromatic hydrocarbons (PAHs). Radiorespirometric analysis revealed that strain KK1 was found to be able to mineralize anthracene, naphthalene and phenanthrene. Notably, phenanthrene-grown cells were able to mineralize anthracene much more rapidly than naphthalene-grown cells. Comparative analysis of amino acid sequences from 17 randomly selected dioxygenases capable of hydroxylating unactivated aromatic nuclei indicated that the enzymes for catabolism of PAHs, such as naphthalene and phenanthrene, might exist redundantly in strain KK1. Northern hybridization for cells grown on naphthalene or phenanthrene, using the putative naphthalene or phenanthrene dioxygenase gene fragment as a probe, suggested that the enzyme for naphthalene catabolism might share some homology in deduced amino acid sequences with phenanthrene dioxygenases. Also, it was found that three lipids (17:0 cyclo, 18:1 omega7c, 19:0 cyclo) increased in response to both naphthalene and phenanthrene, while the shift of other lipids varied from substrate to substrate.