Prevalence and early signs of autism spectrum disorder (ASD) among 18-36 month-old children of Tianjin in China.

OBJECTIVE: The aim of this study is to estimate the prevalence of autism spectrum disorder (ASD) among 18-36 month old children in the Tianjin Municipality of China, and to identify early signs of autistic children and the predictability of each individual symptom. METHODS: A total of 8 000 children were screened to do a questionnaire based on CHAT modified to include more early signs of autism at the age of 18-36 months. Then the at-risk children were reexamined 1.5 years later and ASD children were identified based on DSM-IV. Early signs of autism were analyzed retrospectively by using discriminant function analysis performed among ASD children, children not followed up and children followed up but failing to meet ASD criteria. RESULTS: Three hundred and sixty seven children were screened as being at-risk to ASD, and 22 of them were identified as having ASD in the subsequent diagnosis. The prevalence of ASD was 27.5 per 10 000 in Tianjin of China with a male to female ratio of 4:1. Items addressing social interactions and communications had higher predictability than other items to distinguish autistic children from non-autistic ones. Pretend play, functional play, showing and reading parents' facial expressions distinguished autistic children from those not followed up, nevertheless those followed up but failing to meet ASD criteria were not included. CONCLUSION: The prevalence of ASD found in our study was lower than that reported in some studies by western researchers. Autism has its specific symptoms, such as deficits in social awareness, social relatedness, and social referencing.

Porous iron molybdate nanorods: in situ diffusion synthesis and low-temperature H2S gas sensing.

In the paper, we developed an in situ diffusion growth method to fabricate porous Fe2(MoO4)3 nanorods. The average diameter and the length of the porous nanorods were 200 nm and 1.2-4 µm, respectively. Moreover, many micropores existed along axial direction of the Fe2(MoO4)3 nanorods. In terms of nitrogen adsorption-desorption isotherms, calculated pore size was in the range of 4-115 nm, agreeing well with the transmission electron microscope observations. Because of the uniquely porous characteristics and catalytic ability at low temperatures, the porous Fe2(MoO4)3 nanorods exhibited very good H2S sensing properties, including high sensitivity at a low working temperature (80 °C), relatively fast response and recovery times, good selectivity, and long-term stability. Thus, the porous Fe2(MoO4)3 nanorods are very promising for the fabrication of high-performance H2S gas sensors. Furthermore, the strategy presented here could be expended as a general method to synthesize other hollow/porous-type transition metal molybdate nanostructures by rational designation in nanoscale.

Fe2O3/TiO2 tube-like nanostructures: synthesis, structural transformation and the enhanced sensing properties.

The paper describes for the first time the successful synthesis of Fe(2)O(3)/TiO(2) tube-like nanostructures, in which TiO(2) shell is of quasi-single crystalline characteristic and its thickness can be controlled through adjusting the added amount of aqueous Ti(SO(4))(2) solution. The characterization of samples obtained at different stages using transmission electron microscope indicates that the outer TiO(2) shell is changed gradually from amorphous and polycrystalline phase into quasi-single crystal under thermal actions through the Ostwald ripening process, accompanying the corrosion of the central parts of Fe(2)O(3) nanorods, and the formation of small particles separating each other, leading to the special core/shell nanorods. Furthermore, Fe(2)O(3)/TiO(2) tube-like nanostructures can be transformed into Fe(2)TiO(5) nanostructures after they are thermally treated at higher temperatures. Those nanostructures exhibit enhanced ethanol sensing properties with respect to the monocomponent. Our results imply that not only hollow nanostructures, but also a novel type of nanostructures can be fabricated by the present method for nanodevices.