Highly improved ethanol gas-sensing performance of mesoporous nickel oxides nanowires with the stannum donor doping.

Mesoporous nickel oxides (NiO) and stannum(Sn)-doped NiO nanowires (NWs) were synthesized by using SBA-15 templates with the nanocasting method. X-ray diffraction, transmission electron microscope, energy dispersive spectrometry, nitrogen adsorption/desorption isotherm and UV-vis spectrum were used to characterize the phase structure, components and microstructure of the as-prepared samples. The gas-sensing analysis indicated that the Sn-doping could greatly improve the ethanol sensitivity for mesoporous NiO NWs. With the increasing Sn content, the ethanol sensitivity increased from 2.16 for NiO NWs up to the maximum of 15.60 for Ni0.962Sn0.038O1.038, and then decreased to 12.24 for Ni0.946Sn0.054O1.054 to 100 ppm ethanol gas at 340 °C. The high surface area from the Sn-doping improved the adsorption of oxygen on the surface of NiO NWs, resulting in the smaller surface resistance in air. Furthermore, owing to the recombination of the holes in hole-accumulation lay with the electrons from the donor impurity level and the increasing the body defects for Sn-doping, the total resistance in ethanol gas enhanced greatly. It was concluded that the sensitivity of Sn-doped NiO NWs based sensor could be greatly improved by the higher surface area and high-valence donor substitution from Sn-doping.

Wide bandgap mesoporous hematite nanowire bundles as a sensitive and rapid response ethanol sensor.

In this study, α-Fe2O3 nanowires were synthesized using mesoporous SBA-15 silica as the hard templates with the nanocasting method, and then mesoporous α-Fe2O3 nanowire bundles (NWBs) were separated from the well-dispersed α-Fe2O3 nanowires (NWs) by the centrifugation technique. Both samples were characterized by x-ray diffraction, transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherm and UV-vis spectra. All results indicated that the α-Fe2O3 NWBs with mesoporous structure presented a higher BET surface area (95 m(2) g(-1)) and wider bandgap (2.08 eV) than those of α-Fe2O3 NWs (32 m(2) g(-1) and 1.91 eV). The bandgap of α-Fe2O3 NWBs was in accordance with the bulk α-Fe2O3, while the BET surface area was much higher. The results from the gas-sensing measurement revealed that the α-Fe2O3 NWBs based gas sensor exhibited a high sensitivity of 21.7, fast response-recovery of 7.5 s and 1 s, and good selectivity to ethanol at 340 °C. The sensitivity (21.7) for ethanol of α-Fe2O3 NWBs was much better than that of the α-Fe2O3 NWs (12.2), which should be attributed to the higher BET surface area and wider bandgap of α-Fe2O3 NWBs.

[Study on the associated risk factors of rheumatic pain: a ILAR-China, WHO COPCORD Shantou study].

OBJECTIVE: To validate the difference on the prevalence of rheumatic symptoms between north and south parts of the country and to study the associated risk factors of rheumatic complaints in Shantou city, China. METHODS: A total number of 10 638 people at above 16 years of age from four samples, were surveyed in 1987, 1992, 1995, and 1999. Protocol of International League Against Rheumatism (ILAR)-China collaborative study or WHO-ILAR community oriented program for control of rheumatic disease(COPCORD) core questionnaire was implemented. Data on related rheumatic symptoms were collected and analyzed. RESULTS: The prevalence rate of rheumatic complaints had been increasing in Shantou area during the last decade (in 1987 11.6%, 1992 12.5%, 1995 16.0% and 1999 19.8%) but still lower than that seen in Beijing, China in 1987(40.0%). Rheumatic symptoms were more prevalent in females than in males, in elderly than in young people with most frequently involved site happened in low back area, followed by knee and neck. Lumbar pain was more frequent among rural residents, while neck pain was more prevalent in urban school students. Prevalence of knee pain was significantly higher in people living in multi-storey buildings without elevator than those living in single-storey houses. The peak values of Bone Mineral Density in Shantou population were (0.839 +/- 0.085) g/cm2 in men, and (0.723 +/- 0.064) g/cm2 in women, significantly higher than that reported in 13 other provinces and cities including Beijing. The sense of seeking for medical help was higher in population with higher prevalence of rheumatic symptoms than that in lower complaints group. However, no significant difference was found in the rates of disability among the different populations. CONCLUSION: The prevalence rate of rheumatic complaints was lower in Shantou than that in Beijing. Socio-economic status, environment, sex, age, occupation, ergonomics, bone mineral density, and awareness of seeking medical care might have been the associated risk factors to the prevalence of rheumatic complaints.

Primary gout in Shantou: a clinical and epidemiological study.

OBJECTIVE: To evaluate the prevalence of primary gout in the Shantou area, China, and to understand its clinical features. METHODS: Samples from three surveys of the Chenghai across ten years were studied. Clinical, laboratory and radiology data of 419 cases of primary gout were collected and analyzed. RESULTS: Prevalence of primary gout in the three surveys were 0.17%, 0.15% and 0.26%, respectively. Among the clinical patients, the ratio of male to female was 21:1; the average age of onset of women was significantly higher than that of men. The number of cases in the last ten years has been increasing. In the first wave of cases, the first metatarsophalangeal joint was involved in 82.1% of all cases; no fourth metatarsophalangeal joint involvement had been observed. Hyperlipemia was the most common accompanying abnormal laboratory test (57.1%). Radiographic bone erosion was found in 49.4% patients, most of them with disease duration more than 5 years. CONCLUSIONS: The prevalence of primary gout in Shantou area has been increasing in the last ten years. Changes in diet and lifestyle may be responsible for this rapid increase.