Effects of Simulated Rare Earth Recycling Wastewaters on Biological Nitrification

Increasing rare earth element (REE) supplies by recycling and expanded ore processing will result in generation of new wastewaters. In some cases, disposal to a sewage treatment plant may be favored, but plant performance must be maintained. To assess the potential effects of such wastewaters on biological treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50, and 100 ppm), and the extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions at 50 and 100 ppm inhibited N. europaea, even when virtually all of the REE was insoluble. Provision of TBP with Eu increased N. europaea inhibition, although TBP alone did not substantially alter activity. For N. winogradskyi cultures, Eu or Y additions at all tested levels induced significant inhibition, and nitrification shut down completely with TBP addition. REE solubility was calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, typically controlled by the precipitation of REE hydroxides but also likely affected by the formation of unknown phosphate phases, which determined aqueous concentrations experienced by the microorganisms

Using Potential Path Trees to Map Sex Offender Access to Schools

Many states and municipalities prohibit registered sex offenders from residing near schools or other places where children gather. Such residence restrictions are employed in order to prevent sex crimes against children by reducing sex offender access to possible victims. Although numerous academic studies suggest that residence restrictions fail to reduce crime rates or are otherwise inappropriate, the potential effectiveness of these policies has not thoroughly been evaluated from a spatial accessibility perspective. This study explores the spatial accessibility of sex offenders to public schools in a city with enforced residence restrictions, St. Louis, Missouri. The goal of the analysis is to examine how accessible schools are to sex offenders with a history of crimes against children or minors. Unlike previous studies, however, accessibility is measured not only near the place of residence but also during expected routine activities that occur away from the home, such as at the work place or during commutes. To accomplish this, methods of time geography are used to measure cumulative sex offender accessibility to schools based on the home and work addresses of registered individuals. Specifically, potential path trees are used to estimate sex offender access to schools given estimated daily travel budgets. The results show that, while few registered offenders in the city live near schools, nearly all are expected to come in close proximity to them either near the work place or during the expected journey to work. In the context of public policy, this suggests that—from a strictly spatial perspective—residence restriction laws are unlikely to achieve their goal of limiting sex offender access to school children

The TLX1 oncogene drives aneuploidy in T cell transformation

The TLX1 oncogene (encoding the transcription factor T cell leukemia homeobox protein-1) has a major role in the pathogenesis of T cell acute lymphoblastic leukemia (T-ALL). However, the specific mechanisms of T cell transformation downstream of TLX1 remain to be elucidated. Here we show that transgenic expression of human TLX1 in mice induces T-ALL with frequent deletions and mutations in Bcl11b (encoding B cell leukemia/lymphoma-11B) and identify the presence of recurrent mutations and deletions in BCL11B in 16% of human T-ALLs. Most notably, mouse TLX1 tumors were typically aneuploid and showed a marked defect in the activation of the mitotic checkpoint. Mechanistically, TLX1 directly downregulates the expression of CHEK1 (encoding CHK1 checkpoint homolog) and additional mitotic control genes and induces loss of the mitotic checkpoint in nontransformed preleukemic thymocytes. These results identify a previously unrecognized mechanism contributing to chromosomal missegregation and aneuploidy active at the earliest stages of tumor development in the pathogenesis of cancer