6 research outputs found
Lead Speciation and Bioavailability in Apatite-Amended Sediments
The in situ sequestration of lead (Pb) in sediment with a phosphate amendment was investigated by Pb speciation and bioavailability. Sediment Pb in preamendment samples was identified as galena (PbS) with trace amounts of absorbed Pb. Sediment exposed to atmospheric conditions underwent conversion to hydrocerussite and anglesite. Sediments mixed with apatite exhibited limited conversion to pyromorphite, the hypothesized end product. Conversion of PbS to pyromorphite is inhibited under reducing conditions, and pyromorphite formation appears limited to reaction with pore water Pb and PbS oxidation products. Porewater Pb values were decreased by 94% or more when sediment was amended with apatite. The acute toxicity of the sediment Pb was evaluated with Hyalella azteca and bioaccumulation of Pb with Lumbriculus variegatus. The growth of H. azteca may be mildly inhibited in contaminated sediment, with apatite-amended sediments exhibiting on average a higher growth weight by approximately 20%. The bioaccumulation of Pb in L. variegatus tissue decreased with increased phosphate loading in contaminated sediment. The study indicates limited effectiveness of apatite in sequestering Pb if present as PbS under reducing conditions, but sequestration of porewater Pb and stabilization of near-surface sediment may be a feasible and alternative approach to decreasing potential toxicity of Pb
A Randomized, Double-Blind, Placebo-Controlled, Parallel Study Investigating the Efficacy of a Whole Coffee Cherry Extract and Phosphatidylserine Formulation on Cognitive Performance of Healthy Adults with Self-Perceived Memory Problems
Abstract Introduction Cognition refers to brain functions including memory, learning, and thought processing and is increasingly important to individuals. However, impairment of cognitive function is a concern among North American adults. Therefore, effective and reliable treatments are needed. Methods This randomized, double-blind, placebo-controlled study examined the effects of 42 days of Neuriva® supplementation, a whole coffee cherry extract and phosphatidylserine supplement, on memory, accuracy, focus and concentration and learning among 138 healthy adults (40–65 years) with self-reported memory problems. Plasma brain-derived neurotrophic factor (BDNF) levels, Computerized Mental Performance Assessment System (COMPASS) tasks, the Everyday Memory Questionnaire (EMQ), and Go/No-Go tests were assessed at baseline and day 42. Results As compared to placebo, Neuriva® supplementation elicited greater improvements at day 42 in numeric working memory COMPASS task accuracy outcomes (p ≤ 0.024) which assessed memory, accuracy, and focus and concentration, and reaction time outcomes (p ≤ 0.031) which assessed memory as well as focus and concentration. Neuriva® supplementation improved overall accuracy (p = 0.035) in the picture recognition task that assessed memory, accuracy, and learning compared to placebo. No significant differences between groups were observed for BDNF, the EMQ, or Go/No-Go tests. Conclusion Results suggest 42 days of Neuriva® supplementation was safe, well tolerated, and beneficial in improving memory, accuracy, focus and concentration, and learning in a healthy adult population with self-reported memory problems
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Technical issues associated with in situ vitrification of the INEL Subsurface Disposal Area. Volume 2, Application of technical issues to the Acid Pit
In situ vitrification (ISV) has been identified as an alternative technology for remediation of the Acid Pit and Transuranic Pits and Trenches (TRU-PTs) that are present at the Idaho National Engineering Laboratory (INEL) Subsurface Disposal Area (SDA). However, a number of technical issues exist that must be resolved before ISV can be considered applicable to these waste sites. To assist in the ISV technology evaluation, an ISV Steering Committee was formed to identify, prioritize, and develop closure roadmaps for technical issues associated with ISV application at the INEL SDA. The activities of the ISV Steering Committee are summarized in three volumes of this report. Volume 1 identifies the systematic approach used to identify and prioritize the ISV technical issues, and briefly discusses the methodology that will be employed to resolve these issues. This document Volume 2 and Volume 3 discusses each technical issue in greater detail and suggest specific closure roadmaps to be used in resolving technical issues associated with ISV at the SDA Acid Pit and TRU-PTs, respectively