Rapid and Efficient Arsenic Removal by Iron Electrocoagulation Enabled with in Situ Generation of Hydrogen Peroxide.

Millions of people are exposed to toxic levels of dissolved arsenic in groundwater used for drinking. Iron electrocoagulation (FeEC) has been demonstrated as an effective technology to remove arsenic at an affordable price. However, FeEC requires long operating times (∼hours) to remove dissolved arsenic due to inherent kinetics limitations. Air cathode Assisted Iron Electrocoagulation (ACAIE) overcomes this limitation by cathodically generating H2O2 in situ. In ACAIE operation, rapid oxidation of Fe(II) and complete oxidation and removal of As(III) are achieved. We compare FeEC and ACAIE for removing As(III) from an initial concentration of 1464 μg/L, aiming for a final concentration of less than 4 μg/L. We demonstrate that at short electrolysis times (0.5 min), i.e., high charge dosage rates (1200 C/L/min), ACAIE consistently outperformed FeEC in bringing arsenic levels to less than WHO-MCL of 10 μg/L. Using XRD and XAS data, we conclusively show that poor arsenic removal in FeEC arises from incomplete As(III) oxidation, ineffective Fe(II) oxidation and the formation of Fe(II-III) (hydr)oxides at short electrolysis times (<20 min). Finally, we report successful ACAIE performance (retention time 19 s) in removing dissolved arsenic from contaminated groundwater in rural California

Vascular endothelial growth factor in children with neuroblastoma: a retrospective analysis

BACKGROUND: Despite aggressive therapy, advanced stage neuroblastoma patients have poor survival rates. Although angiogenesis correlates with advanced tumour stage and plays an important role in determining the tumour response to treatment in general, clinical data are still insufficient, and more clinical evaluations are needed to draw conclusions. The aim of this study was to evaluate vascular endothelial growth factor (VEGF) expression in patients with neuroblastoma, determine whether it correlates with other prognostic factors and/or therapeutic response, and to assess should VEGF be considered in a routine diagnostic workup. ----- MATERIALS AND METHODS: VEGF expression was determined by immunohistochemistry using anti-VEGF antibody in paraffin embedded primary tumour tissue from 56 neuroblastoma patients. Semiquantitative expression of VEGF was estimated and compared with gender, age, histology, disease stage, therapy, and survival. Statistical analyses, including multivariate analysis, were performed. ----- RESULTS: VEGF expression correlated with disease stage and survival in neuroblastoma patients. Combination of VEGF expression and disease stage as a single prognostic value for survival (P-value = 0.0034; odds ratio (OR) (95%CI) = 26.17 (2.97-230.27) exhibited greater correlation with survival than individually. Hematopoietic stem cell transplantation significantly improved survival of the advanced stage patients with high VEGF expression. ----- CONCLUSION: VEGF expression should be considered in a routine diagnostic workup of children with neuroblastoma, especially in those more than 18 months old and with advanced disease stage. High VEGF expression at the time of disease diagnosis is a bad risk prognostic factor, and can be used to characterize subsets of patients with an unfavourable outcome

A next-generation liquid xenon observatory for dark matter and neutrino physics

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector

Adapting a drinking water treatment technology for arsenic removal to the context of a small, low-income California community.

Small, low-income, and rural communities across the United States are disproportionately exposed to arsenic contaminated drinking water because existing treatment solutions are too expensive and difficult to operate. This paper describes efforts to overcome some barriers and limitations of conventional iron electrocoagulation (Fe-EC) to enable its use in the rural Californian (U.S.) context. Barriers and limitations of Fe-EC's application in rural California considered in this work include: 1) Frequent labor intensive electrode cleaning is required to overcome rust accumulation, 2) Electrolysis durations are long, reducing throughput for a given system size, and 3) Waste needs compliance with California standards. We report results from an investigation for overcoming these limitations via a field trial on a farm in Allensworth, a small, low-income, rural community in California. Our strategies to overcome each of the above barriers and limitations are respectively, 1) operating the Fe-EC reactor at high current density to result in sustained Fe production, 2) operating at high charge dosage rate with external H2O2, and 3) characterization of the arsenic-laden waste, and are discussed further in the paper. Main findings are: (1) Fe-EC removed arsenic consistently below the federal (and state) standard of 10 µg/L, (2) high current density failed to sustain Fe production whereas low current density did not, (3) electrolysis time decreased from > 1 hour to < 2 min with H2O2 dosing of 5 mg/L at higher charge dosage rates, (4) dilution of As-sludge is required to comply with State's non-hazardous waste status, and (5) discrepancies were observed between lab and field results in using current density to overcome labor-intensive electrode cleanings. Finally, implications of overcoming limitations to scale-up of Fe-EC in relevant California communities are discussed