Photocatalytic degradation of methyl orange by CeO2 and Fe-doped CeO2 films under visible light irradiation.

Undoped CeO2 and 0.50-5.00 mol% Fe-doped CeO2 nanoparticles were prepared by a homogeneous precipitation combined with homogeneous/impreganation method, and applied as photocatalyst films prepared by a doctor blade technique. The superior photocatalytic performances of the Fe-doped CeO2 films, compared with undoped CeO2 films, was ascribed mainly to a decrease in band gap energy and an increase in specific surface area of the material. The presence of Fe(3+) as found from XPS analysis, may act as electron acceptor and/or hole donor, facilitating longer lived charge carrier separation in Fe-doped CeO2 films as confirmed by photoluminescence spectroscopy. The 1.50 mol% Fe-doped CeO2 film was found to be the optimal iron doping concentration for MO degradation in this study.

Synthesis of Fe3O4/SiO2/CeO2 core-shell magnetic and their application as photocatalyst.

The Fe3O4/SiO2/CeO2 core-shell magnetic has been successfully synthesized by three steps of hydrothermal, sonochemical and homogeneous precipitation by coating CeO2 nanoparticles onto Fe3O4/SiO2 magnetic core. The prepared samples were characterized by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FESEM) connected with energy dispersive X-ray analysis system (EDS), high resolution transmission electron microscopy (HRTEM), Nitrogen adsorption-desorption analyses (BET), and vibrating sample magnetometer (VSM). The photocatalytic activities for Fe3O4/SiO2/CeO2 core-shell magnetic under UV and visible lights were measured by determining the degradation rate of formic and oxalic acid in spiral reactor for 120 min. The amounts of CO2 generated during the process were compared between the magnetic catalyst and bare CeO2. After the finished photocatalytic degradation, the magnetic catalyst was recovered by external magnetic field at the end of each experiment. The results showed that the photocatalytic activity of Fe3O4/SiO2/CeO2 core-shell magnetic had higher than that of bare CeO2 and was found to be constant for three cycles of the recycled use.

CO detection of hydrothermally synthesized Pt-loaded WO3 films.

Unloaded WO3 and 0.25-1.0 wt% Pt-loaded WO3 nanoparticles were synthesized by hydrothermal method using sodium tungstate dihydrate and sodium chloride as precursors in the acidic condition and further by the impregnation method using platinum acetylacetonate. Pt-loaded WO3 films on Al2O3 substrate interdigitated with Au electrodes were prepared by spin-coating technique. The temperature has an obvious influence on the response of sensors to CO gas. In order to determine the optimal operating temperatures, the response of WO3 sensors with different Pt loading concentrations towards 50-2000 ppm of CO in air was tested as a function of operating temperature of 150-350 degrees C. It was found that 1.0 wt% Pt-loaded WO3 sensing film showed the highest response of - 469 at 2000 ppm CO (250 degrees C). Therefore an optimal operating temperature of 250 degrees C was chosen for CO detection.

Enhanced ethanol selectivity of flame-spray-made Au/ZnO thick films.

Sensing characteristics of the spin-coated Au/ZnO nanoparticles thick films with different Au concentrations have been studied for various gases, namely, CO, SO2, ethanol and acetone. The influence on a dynamic range of Au concentration on ethanol response (0.005-0.1 vol.%) of thick film sensor elements was studied at the operating temperatures ranging from 300 to 400 degrees C in the presence of dry air. The optimum Au concentration was found to be 0.5 mol%. 0.5 mol% Au exhibited an optimum ethanol response of 5.0 x 10(2) and a short response time (10 s) for ethanol concentration of 0.1 vol.% at 400 degrees C. Plausible mechanisms explaining the enhanced ethanol selectivity by thick films of Au/ZnO are discussed.

The effect of Mn on flame spray pyrolysis-made ZnO nanoparticles for flammable gases detection.

The application of Mn-loaded ZnO nanoparticles to the design of flammable gas sensors is nowadays one of the most active research fields, due to their high activity, good adsorption characteristics and high selectivity with high response to toxic and combustible gases. It is sensitive to many gases at moderate temperature, such as C2H4, CH4 and C2H2 gases. FSP presents a new technique for 0.25-1.00 mol% Mn-loaded ZnO nanoparticles synthesis which involves only a single step. The crystallite sizes of ZnO spherical and hexagonal particles were found to be ranging from 5 to 15 nm while ZnO nanorods were seen to be 5-15 nm in width and 20-40 nm in length. In addition, very fine Mn nanoparticles were uniformly deposited on the surface of ZnO particles. The highest response for CH4 gas was -240 towards 0.50 mol% Mn-loaded ZnO at 1.0 vol.% concentration of CH4 in dry air at 300 degrees C. The response of 0.50 mol% Mn-loaded ZnO of C2H4 gas was as high as 72 for 1.0 vol.% while the response for C2H2 gas was -13 towards 0.50 mol% Mn-loaded ZnO at 1.0 vol.% concentration of C2H2 in dry air at 300 degrees C.

Pt/C doped TiO2/SWNTs as catalyst for methanol oxidation.

Platinum/carbon doped titanium dioxide/single-walled carbon nanotubes (Pt/C/TiO2/SWNTs) were successfully prepared by blending method. These composite catalysts were found to exhibit an anatase TiO2 structure with uniform Pt/C and the existence of SWNTs can be confirmed by transmission electron microscopy (TEM). The composite of Pt/C with TiO2/SWNTs could improve an enhancement in catalytic properties upon applying TiO2/SWNTs as catalyst support. The catalytic oxidation of methanol of Pt/C doped TiO2/SWNTs is found to be higher as compared to the undoped and Pt/C doped materials.

Risk factors between analgesic use and chronic nephropathy in Thailand.

Analgesic abuse is common in Thailand. Heavy use of analgesic may also increase risk of chronic nephropathy. However, the extent of this risk remains unclear. We carried out a case-control study in three referral hospitals. A total of 84 patients with newly diagnosed of chronic tubulointerstitial nephritis were enrolled as cases. Two control groups were randomly selected, 192 from hospitalized patients who had no renal disease and serum creatinine below 1.2 mg/dl and 166 from relatives of friends visiting the hospitals. Both cases and controls were interviewed by a standardized pre-coded questionnaire to obtain histories of analgesic use before diagnosis of renal disease. On multiple logistic regression analysis, patients whose estimated lifetime use of acetaminophen of 1,000 g or more had an increased risk of chronic nephropathy compared with non-users, the odds ratio (OR) was 5.9 (95% confidence interval (CI) 1.3-25.6, hospital controls) and OR = 5.8 (95% CI 1.04-31.9, visitor controls). Also, uses of aspirin showed a similar relationship. Patients who used aspirin 1,000 g or more per lifetime had higher risk of chronic nephropathy when compared to non-users, the odds ratio were 7.1 (95% CI 2.0-25.8, hospital controls) and 20.4 (95% CI 2.4-174.2) for visitor controls. These data indicate that analgesic abuse increased risk of chronic nephropathy in Thailand.

Asymptomatic bacteriuria in health and glomerulonephropathies.

In a comparative study of prevalence of asymptomatic bacteriuria in a Thai population, 1.4% of 955 apparently healthy adults (12 female and 1 male) were found to have positive urine culture. Of these, 6 individuals grew staphylococcal coagulase-negative, 3 grew E. coli, and the rest grew various other organisms. Among 176 patients with glomerulonephropathies (GNP), 20.5% (17 male and 16 female) yielded positive urine cultures. These included 18 positive for E. coli, 3 for staphylococcal coagulase-negative, 5 for Klebsiella and 3 for Enterobacter; the rest grew various other organisms. There was a higher overall prevalence of asymptomatic bacteriuria in GNP when compared to the controls. Heavy proteinuria is also a predisposing factor for an increase in the prevalence of asymptomatic bacteriuria in female GNP only.

Hepatitis B virus infection in Thai hemodialysis patients.

The prevalence of hepatitis B virus infection in chronic hemodialysis patients in Bangkok was surveyed. There were 14.7% (10 out of 68 patients) HBAg carriers; 26.5% (18 out of 68 patients) positive for HBAb. Total exposure rate of HBV (28 out of 68 patients) was 41.2% at the beginning of dialysis. The exposure rate converted to be 50% (34 out of 68 patients) at the time of survey. Five cases with abnormal liver function expired while being on the hemodialysis. Acute viral hepatitis was thought to be the cause. One case of possible non A- non B viral hepatitis was discussed.

Short-term effect of 4% hypertonic glucose as compared to 4% mixed hypertonic mannitol solution in conventional peritoneal dialysis.

16 peritoneal dialyses were performed in 14 end-stage kidney disease patients; 6 had diabetic nephropathy, and, of the nondiabetic group, 7 had chronic glomerulonephritis, and 1 had polycystic kidney disease. The peritoneal dialysis performed with conventional 1.5% glucose solution, intervened by four consecutive exchanges using 4% hypertonic glucose solution, was compared to 4% mixed hypertonic mannitol solution in the diabetic and nondiabetic group. There was no significant change of serum glucose, when postdialysis with 1.5% glucose solution was compared to 4% mixed hypertonic mannitol solution; however there was a significant change of serum osmolality in both groups. Postdialysis with both 4% hypertonic solutions showed that there was no significant difference of ultrafiltration volume in both groups of patients, but there was a significant difference in serum glucose in the diabetic group. The transport mechanism of mixed hypertonic mannitol solution as compared to hypertonic glucose solution is discussed. The application of hypertonic mannitol solution for clinical use is not advised.

Renal tubular acidosis with simultaneous lactic and keto acidoses: unusual manifestations of acute myelomonoblastic leukemia.

A 16-year-old male with severe metabolic acidosis required huge doses of sodium bicarbonate to alleviate his symptoms. Subsequent investigation showed that his bone marrow and kidneys were infiltrated with myelomonoblasts. His clinical course showed a temporal relationship between acute myelomonoblastic leukemia and metabolic acidosis. The literature on various etiologies of metabolic acidosis is reviewed. This is probably the first documented case of acute leukemia with the simultaneous occurrence of renal tubular, lactic and ketoacidoses.

Exchange transfusion in cerebral malaria complicated by disseminated intravascular coagulation.

A patient with cerebral malaria complicated by full-blown DIC, after failing to respond to other forms of treatment, was successfully treated by exchange transfusion. To the best of the authors' knowledge, this may be first reported case of full-blown DIC in malaria successfully treated by exchange transfusion.