Selenium in selenium-rich rice sold in China and risk assessment.

Selenium-rich rice samples of 52 brands were bought from supermarkets on line in China and analysed for Se with ICP-MS. The Se concentration of Se-rich rice in China ranged from 0.012 ± 0.001 to 0.558 ± 0.057 mg/kg with an average of 0.090 ± 0.092 mg/kg. Rice samples with Se concentrations below 0.04 mg/kg accounted for 36.5% of the total samples. Se concentrations between 0.04 and 0.3 mg/kg accounted for 61.6%. Taking the upper tolerable limit of 400 µg/d as the risk standard, the risk of selenium intake by selenium-rich rice was low and the risk index was far less than 100%. With the upper intake limit of 100 µg/d and the adequate intake of 70 µg/d as the risk standard, the maximum intake risk index was higher than 100%, indicating a certain risk in the consumption of selenium-rich rice.

Hydrothermal synthesis and electrochemical properties of KMn8O16 nanorods for lithium-ion battery applications.

KMn8O16 nanorods were prepared through a facile hydrothermal method by using KMnO4 and MnSO4 as reactants. The KMn8O16 samples synthesized at different temperatures (100-160 degrees C) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and its electrochemical properties were tested by galvanostatic charge/discharge system. The effect of reaction temperature on the morphology and electrochemical properties was investigated. As electrode materials for the lithium ion battery cycled between 1.5 and 4.2 V, the KMn8O16 nanorods synthesized at 160 degrees C show the highest reversible discharge capacity (160.1 mA h/g even after 50 cycles at current density of 50 mA/g) and the best cycling stability. These results indicate that the KMn8O16 nanorods could be a promising cathode material for lithium ion batteries.

Synthesis and Characterization of Cobalt-Doped WS2 Nanorods for Lithium Battery Applications.

Cobalt-doped tungsten disulfide nanorods were synthesized by an approach involving exfoliation, intercalation, and the hydrothermal process, using commercial WS2 powder as the precursor and n-butyllithium as the exfoliating reagent. XRD results indicate that the crystal phase of the sample is 2H-WS2. TEM images show that the sample consists of bamboo-like nanorods with a diameter of around 20 nm and a length of about 200 nm. The Co-doped WS2 nanorods exhibit the reversible capacity of 568 mAh g-1 in a voltage range of 0.01-3.0 V versus Li/Li+. As an electrode material for the lithium battery, the Co-doped WS2 nanorods show enhanced charge capacity and cycling stability compared with the raw WS2 powder.