Ramie (Boehmeria nivea)'s uranium bioconcentration and tolerance attributes.

The authors sampled and analyzed 15 species of dominant wild plants in Huanan uranium tailings pond in China, whose tailings' uranium contents were 3.21-120.52 µg/g. Among the 15 species of wild plants, ramie (Boehmeria nivea) had the strongest uranium bioconcentration and transfer capacities. In order to study the uranium bioconcentration and tolerance attributes of ramie in detail, and provide a reference for the screening remediation plants to phytoremedy on a large scale in uranium tailings pond, a ramie cultivar Xiangzhu No. 7 pot experiment was carried out. We found that both wild ramie and Xiangzhu No. 7 could bioconcentrate uranium, but there were two differences. One was wild ramie's shoots bioconcentrated uranium up to 20 µg/g (which can be regarded as the critical content value of the shoot of uranium hyperaccumulator) even the soil uranium content was as low as 5.874 µg/g while Xiangzhu No. 7's shoots could reach 20 µg/g only when the uranium treatment concentrations were 275 µg/g or more; the other was that all the transfer factors of 3 wild samples were >1, and the transfer factors of 27 out of 28 pot experiment samples were <1. Probably wild ramie was a uranium hyperaccumulator. Xiangzhu No. 7 satisfied the needs of uranium hyperaccumulator on accumulation capability, tolerance capability, bioconcentration factor, but not transfer capability, so Xiangzhu No. 7 was not a uranium hyperaccumulator. We analyzed the possible reasons why there were differences in the uranium bioconcentration and transfer attributes between wild ramie and Xiangzhu No. 7., and proposed the direction for further research. In our opinion, both the plants which bioconcentrate contaminants in the shoots and roots can act as phytoextractors. Although Xiangzhu No. 7's biomass and accumulation of uranium were concentrated on the roots, the roots were small in volume and easy to harvest. And Xiangzhu No. 7's cultivating skills and protection measures had been developed very well. Xiangzhu No. 7's whole bioconcentration factors and the roots' bioconcentration factors, which were 1.200-1.834 and 1.460-2.341, respectively, increased with the increases of uranium contents of pot soil when the soil's uranium contents are 25-175 µg/g, so it can act as a potential phytoextractor when Huanan uranium tailings pond is phytoremediated.

A two-dimensional assessment of selected medical websites.

Two major dimensions are commonly used for assessing the breadth and depth of the information content in medical websites. The first dimension deals with quality characteristics consisting of authorship, attribution, confidentiality, currency, disclosure, legitimacy and purpose. Functional variables such as access to medical libraries, reference books, health organisations, information sites, guidelines and reviews, clinical trial sites, drug questions, locating an expert and alternative medicine make up the second dimension. The trend is toward the use of both dimensions for evaluating medical websites. This study examines the breadth and depth of the medical information in the websites of the top 51 medical schools in the USA. The results of this study indicate that there are certain quality-standard measures that are present in all medical websites. However, there are also clear distinctions in quality as well as functional attributes that separate the higher-ranked medical schools from the lower ones. Medical professionals, computer system developers, and end-users of medical information will find the results of this study useful.