孤独症谱系障碍者视觉定向与视觉搜索的特点及神经机制

定向网络是注意网络的重要组成部分,主要包括视觉定向与视觉搜索两大任务。对于这两大注意任务,正常个体在神经机制上存在较大的重叠,然而,孤独症个体却表现出截然相反的行为证据。研究者从非社会信息的注意视角发现,一般而言,在视觉定向上,孤独症个体注意转移不存在缺陷,而注意脱离存在困难,但该结论仍有争议;在视觉搜索上,孤独症个体存在视觉搜索优势,但该优势发生的阶段及原因仍需进一步探究。未来研究应进一步考察孤独症个体在视觉定向任务中左右视野的不对称性、视觉搜索优势的内在机制及两大注意任务之间的相互关系。

Effects of silver nanoparticles on resistance characteristics of the wetland plant Typha orientalis in a hydroponic system

To probe the influence and the adverse-resistance characteristics of wetland plants in presence of silver nanoparticles (AgNPs), the changes in the physiological and biochemical characteristics (including the superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase (POD) activity, soluble protein content, and chlorophyll content) of Typha orientalis exposed to different concentrations of AgNPs solutions (0, 0.1, 1, 20 and 40 mg/L) were explored. Meantime, the accumulation of silver content in these plants was revealed. The results show that under low concentrations of AgNPs, the SOD and POD activities in the leaves of Typha orientalis are strengthened to different degrees. However, high concentrations of AgNPs inhibit the activities of SOD and POD. Under the stress of different concentrations of AgNPs, the CAT activities are inhibited initially and later recovered to some extent. Under the stress of low concentrations of AgNPs, the soluble protein content in the leaves of Typha orientalis increases significantly, but decreases more significantly with increasing concentrations of AgNPs. Low concentrations of AgNPs promote chlorophyll synthesis in the leaves of Typha orientalis , but the chlorophyll content subsequently falls to pre-stress levels. In contrast, high concentrations of AgNPs cause a certain inhibition to generate chlorophyll. Meanwhile, the results show that the silver concentrations of plant tissues increase with the exposure of concentrations of AgNPs and they have a positive relationship with the exposure of concentrations of AgNPs.

Migration of silver nanoparticles in an aquatic system with Eichhornia crassipes

The migration and dissolution of AgNPs in an aquatic system with plants was investigated.By using a hydroponic system with Eichhornia crassipes,the absorption and transportation processes of silver nanoparticles were investigated.The results show that AgNPs concentrations in the water phase declined with the increase in time,and the reduction degree was dependent on the initial concentrations of AgNPs.The silver concentrations in the roots(r=0.98,p<0.05),stems and leaves(r=1,p<0.001)were significantly positively correlated with the initial concentrations of AgNPs.Silver nanoparticles accumulated in plant roots more than stems and leaves.Compared with the addition of AgNO 3 at identical concentrations,lower removal rates of silver and plant uptake were observed in the AgNPs stress systems.A significant positive correlation was also found between the initial AgNPs concentrations and the removed amount of silver(r=0.99,p<0.001).For AgNPs,the primary removal mechanisms in these aquatic systems were agglomeration and sedimentation,while the absorption by plants had a relatively weak contribution.

Preparation of Au Nanoparticles Decorated Polyaniline Nanotube and Its Catalytic Oxidation to Ascorbic Acid

With sulfonated electrospun polystyrene fiber as a template, uniform polyaniline（PANI） nanotubes were fabricated via polymerization of aniline followed by template removal. Au nanoparticles（Aunano） were decorated on the PANI nanotube successfully via auto-reduction of HAuCl4 on the PANI nanotube. The morphology of the nanotubes was characterized by means of scanning electron microscopy（SEM） and transmittance electron microscopy（TEM）. By varying precursor concentration and incubation time, Aunano-PANI with different size of Aunano was obtained conveniently. Glassy carbon electrode modified with the Aunano decorated PANI nanotubes （Auna,o-PANI/GCE） was prepared and used seccessfully for the catalytic oxidation of ascorbic acid（AA）. The results of differential pulse voltammetry indicate that there is a good linear relationship between the peak currents and the concentrations of AA in the range of 5-3000 μmol/L, with the limit of detection of 1 μmol/L（S/N〉3）. There is no mutual interference between AA and dopamine. The electrode has been successfully applied in the detection of AA in vitamin C tablet sample.