Search

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants known to adversely affect health and development in many taxa. Although PFAS generally occur as mixtures in the environment, little is known about the effects of PFAS mixtures on organisms compared to single chemical exposures. Moreover, PFAS exposure in nature occurs alongside biotic factors such as parasitism. Even though host-parasite interactions are common in natural systems, there is little information about how PFAS affect these interactions. Here, we examined the effects of PFAS mixtures on the susceptibility of larval American bullfrogs (

Despite benefits to the firefighting industry, the release of per- and polyfluoroalkyl substances (PFASs) from aqueous film-forming foam (AFFF) into aquatic systems poses significant risks to human health and other organisms. While anion-exchange technologies have proven to be effective for removing perfluoroalkyl acids (PFAAs) from water, their effectiveness for removing the diverse PFAS structures discovered in AFFF remains unknown. Here, we report on the adsorption of 75 PFASs, including 63 polyfluorinated substances, in a diluted AFFF mixture using 14 commercially available ion-exchange (IX)/nonionic resins and granular activated carbon (GAC). Results showed that anion-exchange resins (AERs) exhibited significant adsorption of PFASs compared to cation-exchange resins (CERs), nonionic resins (NIRs), and GAC regardless of the PFAS's predicted charge. Isotherm data showed that macroporous AERs have a higher PFAS adsorption capacity compared to gel-type AERs. Cross-correlation comparison of PFAS/Cl- selectivity coefficients (Kex) for each PFAS-AER combination showed that the hydrophobicity of the AER functional group, and polymer matrix played a dominant role in determining resin affinity for PFASs. PFAS structural characteristics also significantly affected adsorption, with increasing chain length and a net negative charge increasing the extent of adsorption. Results from this study provide guidelines for the selection of resins to adsorb a wider range of PFASs and meaningful insights for the development of quantitative models for IX treatment of AFFF-impacted water.

The widespread use of aqueous film-forming foam (AFFF) for firefighting activities (e.g., fire training to extinguish fuel-based fires at aircraft facilities) has led to extensive groundwater and soil contamination by per- and polyfluoroalkyl substances (PFASs) that are highly recalcitrant to destruction using conventional treatment technologies. This study reports on the hydrothermal alkaline treatment of diverse PFASs present in AFFFs. Quantitative and semiquantitative high-resolution mass spectrometry analyses of PFASs demonstrate a rapid degradation of all 109 PFASs identified in two AFFFs (sulfonate- and fluorotelomer-based formulations) in water amended with an alkali (e.g., 1-5 M NaOH) at near-critical temperature and pressure (350 °C, 16.5 MPa). This includes per- and polyfluoroalkyl acids and a range of acid precursors. Most PFASs were degraded to nondetectable levels within 15 min, and the most recalcitrant perfluoroalkyl sulfonates were degraded within 30 min when treated with 5 M NaOH. 19F NMR spectroscopic analysis and fluoride ion analysis confirm the near-complete defluorination of PFASs in both dilute and concentrated AFFF mixtures, and no stable volatile organofluorine species were detected in reactor headspace gases by the gas chromatography-mass spectrometry analysis. These findings indicate a significant potential for application of hydrothermal treatment technologies to manage PFAS waste streams, including on-site treatment of unused AFFF chemical stockpiles, investigation-derived wastes, and concentrated source zone materials.

Hydrothermal alkaline treatment (HALT) can effectively degrade per- and polyfluoroalkyl substances (PFASs) present in aqueous film-forming foam (AFFF). However, information is lacking regarding the treatment of PFASs in actual groundwater and soil from AFFF-impacted sites, especially for complex soil matrices. Given the lack of studies on direct soil treatment for PFAS destruction, we herein applied HALT to two groundwater samples and three soil samples from AFFF-impacted sites and characterized the destruction of PFASs using high-resolution mass spectrometry. Results showed that the 148 PFASs identified in all collected field samples, including 10 cationic, 98 anionic, and 40 zwitterionic PFASs, were mostly degraded to nondetectable levels within 90 min when treated with 5 M NaOH at 350 °C. The near-complete defluorination, as evidenced by fluoride release measurements, confirmed the complete destruction of PFASs. While many structures, including perfluoroalkyl carboxylic acids and polyfluorinated substances, were readily degraded, perfluoroalkyl sulfonates (PFSAs, C

There is increasing concern over the presence of per- and polyfluoroalkyl substances (PFAS) in biosolids, while sales in commercially available biosolid-based products used as soil amendments are also increasing. Here, the occurrence of 17 perfluoroalkyl acids (PFAAs) present in 13 commercially available biosolid-based products, six organic composts (manure, mushroom, peat, and untreated wood), and one food and yard waste compost were studied. The PFAA concentration ranges observed are as follows: biosolid-based products (9.0-199 μg/kg)food and yard waste (18.5 μg/kg)other organic products (0.1-1.1 μg/kg). Analysis of 2014, 2016, and 2018 bags produced from one product line showed a temporal decrease in the total PFAAs (181, 101, and 74 μg/kg, respectively). The total oxidizable precursor (TOP) assay revealed the presence of PFAA precursors in the biosolid-based products at much higher levels, when the soluble carbon was removed by the ENVI-Carb clean-up prior to the TOP assay. Time-of-flight mass spectrometry confirmed the presence of three sulfonamides, two fluorotelomer sulfonates, and several polyfluoroalkyl phosphate diesters. Pore-water concentrations of water-saturated products were primarily of short-chain PFAAs and increased with increasing PFAA concentrations in the products. A strong positive log-linear correlation between organic carbon (OC)-normalized PFAA partition coefficients and the number of CF

Bench-scale experiments were performed to evaluate the electrochemical oxidation, via direct anodic oxidation and indirect oxidation from salt-derived species, of diluted aqueous film forming foam (AFFF) in brine solutions to mimic anion exchange resin regenerant solutions that are loaded with poly- and perfluoroalkyl substances (PFASs). Results showed that initial transformations of the polyfluorinated compounds, which accounted for approximately 45% of the organic fluorine in the initial mixtures, occurred primarily via an indirect oxidation pathway that targeted the non-fluorinated head groups. Depending on the brine solution, this indirect oxidation likely occurred via hydroxyl radical production or salt-derived oxidants (e.g., SO4˙− derived from anodic oxidation of sulfate). However, perfluoroalkyl acid (PFAA) transformation and the overall rate of defluorination were controlled via a combination of direct and indirect electron transfer. Chloride levels (>0.2% by weight) and the presence of 100 mM of the radical scavenger tert-butyl alcohol substantially reduced pseudo first order defluorination rate constants by up to 80%. Evaluation of fluorine mass balances (via fluoride generation and PFAS levels) suggested that up to approximately 41% (based on a fluorine mass balance) electrochemically transformed intermediate products were not identified under some conditions. Thus, evaluating electrochemical treatment effectiveness solely on the disappearance of PFAAs and other suspect analytes described in current analytical libraries could substantially underestimate the PFAS mass remaining in AFFF-impacted waters.

The ongoing contamination of groundwater with per- and polyfluoroalkyl substances (PFAS) has resulted in a global and rapidly growing interest in PFAS groundwater remediation. Preferred technologies that lead to PFAS destruction are often limited by not addressing all PFAS, being energy-intensive or not being suited for in-situ application. We developed nNiFe-activated carbon (AC) nanocomposites and demonstrated varying degrees of PFAS reduction and fluoride generation with these nanocomposites in batch reactors for several PFAS. Here we explore nNiFe-AC's effectiveness to transform perfluoroalkyl acid acids (PFAAs) under steady-state flow (0.0044 to 0.15 mL/min) in nNiFe-AC:sand packed columns. Column experiments included, two perfluorooctane sulfonate (PFOS) in deionized water and two PFAA mixtures in deionized water or bicarbonate buffer containing five perfluoroalkyl carboxylates (PFCAs, C5-C9) and three perfluoroalkyl sulfonates (PFSAs, C4, C6 and C8) at temperatures of 50 or 60°C were evaluated. PFOS transformation was similar in PFOS-only and PFAA mixture column experiments. Overall, % PFAA transformation under flow conditions exceeded what we observed previously in batch reactors with up to 53% transformation of a PFAA mixture with ∼ 8% defluorination. Longer chain PFAS dominated the PFAAs transformed and a bicarbonate matrix appeared to reduce overall transformation. PFAA breakthrough was slower than predicted from only sorption due to transformation; some longer chain PFAS like PFOS did not breakthrough. Here, nNiFe-AC technology with both in-situ and ex-situ potential application was shown to be a plausible part of a treatment train needed to address the ongoing challenge for cleaning up PFAS-contaminated waters.

Aqueous film-forming foams (AFFFs) are important sources of per- and polyfluoroalkyl substances (PFASs) in soil, groundwater, and surface water. Soil microorganisms can convert polyfluorinated substances into persistent perfluoroalkyl acids, but the understanding of co-contaminant stimulation or inhibition of PFASs biotransformation is limited. In this study, we investigate how aerobic biotransformation of polyfluorinated substances was affected by common AFFF co-contaminants, such as gasoline aromatics: benzene, toluene, ethylbenzene, and

Per- and polyfluoroalkyl substances (PFASs) used in aqueous film-forming foam (AFFF) comprise some perfluoroalkyl substances but a larger variety of polyfluoroalkyl substances. Despite their abundance in AFFF, information is lacking on the potential transformation of these polyfluoroalkyl substances. Due to the biological and chemical stability of the repeating perfluoroalkyl -(CF

A simple method was developed using heated ultrasound-assisted extraction (UAE) with ethanol and an ENVI-Carb clean-up step for quantifying paclitaxel from various parts (leaf, stem, bark a...

Here, we report a promising new strategy for achieving rapid and complete destruction of perfluorooctanesulfonate (PFOS) through the application of hydrothermal conditions (condensed water, 200–350...

Composting the organic fraction of municipal solid waste (OFMSW) creates a nutrient rich soil amendment and reduces the amounts of wastes going to landfills or incineration. However, the occurrence...

Per-and poly-fluoroalkyl substances (PFASs) are a class of persistent compounds that are resistant to degradation. Here we developed an effective method of degrading perfluorooctanesulfonate (PFOS) by hydrated electrons (eaq−) that are generated from 3-indole-acetic-acid (IAA) upon UV irradiation. The method takes advantage of spatial proximity of IAA and PFOS by their co-sorption to an organic polymer, 12-aminolauric acid (ALA), which was pre-intercalated into the interlayer space of an expandable clay mineral, montmorillonite. The interlayer spacing of this clay nanocomposite is greatly expanded relative to unmodified montmorillonite. The maximum adsorption capacity of IAA and PFOS is 168 and 1550 mmol/kg, respectively. This process achieved 40–70% defluorination of a 10 ppm PFOS solution at neutral pH in a 325 mL vessel. The presence of bicarbonate and chloride ions, or natural groundwater showed a minimal impact on PFOS degradation. Based on identification of prominent degradation products, a degradation pathway is proposed, where the primary degradation process is breakage of the C-F bonds (with fluorine replaced by hydrogen), with some cleavage of the C C bond. This approach provides an alternative for treating concentrated PFAS solutions under ambient conditions.

A key gap in the literature on the treatment of per- and polyfluoroalkyl substances (PFAS) in impacted water is the absence of a review article dedicated to anion exchange resin (AER) treatment. This gap is important because previous research has consistently shown adsorption by AER to be one of the most effective treatment processes for PFAS removal from impacted water, and AER is one of the most commonly deployed technologies in the field. Given the scope of the previous review articles on PFAS removal by various adsorbent types, the sections on AER do not explore the full depth of PFAS and AER interactions nor cover the breadth of AER testing conditions. Accordingly, the goal of this paper was to critically review the available peer-reviewed literature on PFAS removal from water by AER. The specific objectives of the review were to synthesize the previous literature results on (1) batch adsorption behavior, (2) impact of water chemistry conditions, (3) continuous-flow adsorption, (4) adsorption modeling, (5) regeneration, and (6) weak-base AER. Following from critical review of the literature, the future research priorities discussed include: (i) improving the underlying science that governs PFAS–resin interactions, (ii) improving methods for resin regeneration and management of PFAS-contaminated concentrate streams, and (iii) comparative life cycle environmental and economic analyses for ion exchange treatment systems relative to competing technologies.

Global phase out of perfluorooctanesulfonic acid (PFOS) has led to increasing production of alternatives such as the chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs) for which little is known on their environmental fate. In this study, sorption by soils, aerobic soil biodegradation, and oxidation potential of 6:2 Cl-PFESA (9-chlorohexadecafluoro-3-oxanonane-1-sulfonate) and 8:2 Cl-PFESA (9-chlorooctadecafluoro-3-oxanonane-1-sulfonate) were evaluated. 6:2 Cl-PFESA sorption was quantified for aqueous and acetone/water solutions, whereas 8:2 PFESA could only be accurately measured in acetone/water solutions. The log–linear cosolvency model was applied and validated to estimate sorption of 8:2 Cl-PFESA. Only soil organic carbon (OC, 0.76–4.30%) was highly and positively correlated to sorption of the Cl-PFESAs (R2 > 0.96). The resulting log Koc values (OC-normalized sorption coefficients) are 4.01 ± 0.09 (n = 6) and 5.54 ± 0.05 (n = 4) L kg–1 for 6:2 Cl-PFESA and 8:2 Cl-PFESA, respectively. Aerobic...

Pressures to ban bisphenol A (BPA) has led to the use of alternate chemicals such as BPA analogues bisphenol S (BPS) and bisphenol AF (BPAF) in production of consumer products; however, information on their environmental fate is scarce. In this study, aerobic degradation of BPA, BPAF, and BPS at 100 μg/kg soil and 22 ± 2 °C was monitored for up to 180 days in a forest soil and an organic farm soil. At each sampling point, soils were extracted three times and analyzed by liquid chromatography high resolution mass or time-of-flight mass spectrometry. Based on compound mass recovered from soils compared to the mass applied, BPS had short half-lives of1 day in both soils similar to BPA. BPAF was much more persistent with observed half-lives of 32.6 and 24.5 days in forest and farm soils, respectively. To our knowledge, this is the first report on BPAF degradation. For all three compounds, half-lives were longer in the higher organic carbon (OC) forest soil which correlates well to sorption studies showing higher sorption with higher OC. Metabolites identified for all three bisphenols support degradation pathways that include meta-cleavage as well as ortho-cleavage, which has not been previously shown.

The degradation and distribution of bisphenol A (BPA), bisphenol S (BPS) and bisphenol AF (BPAF) were evaluated in dilute anaerobic sludge slurries amended with a single bisphenol or a mixture of all three and maintained under methanogenic conditions over a 28-d period. No significant degradation of the bisphenols was observed in methane-generating microcosms. Rapid sorption to sludge particles was the primary removal process with sorption observed: BPAF > BPA > BPS. Several other trace organic chemicals of concern in the sludge were detected using quadrupole time of flight mass spectrometry. Of those detected, triclosan and triclocarban had sufficiently high intensities to quantify changes over the 28-d period in the bisphenol-amended microcosms. Similar to the bisphenols, triclosan and triclocarban concentrations also did not significantly change over the 28-d period with concentrations quantified at 2021 ± 627 and 1864 ± 769 μg/kg dry weight, respectively. Findings exemplify that methane-generating microcosms do not appear conducive to significant degradation of trace organics of concern in anaerobic sludge digesters. HighlightBisphenol A, S and AF as well as triclocarban and triclosan are not degraded under methane producing conditions.Removal from the liquid is through sorption to sludge particles and not biodegradation.Methane producing conditions are not suitable for achieving significant biodegradation of organics of concern. Bisphenol A, S and AF as well as triclocarban and triclosan are not degraded under methane producing conditions. Removal from the liquid is through sorption to sludge particles and not biodegradation. Methane producing conditions are not suitable for achieving significant biodegradation of organics of concern.

Anion exchange resin (AER) adsorption is an established technology for water treatment and groundwater remediation. Two contaminants amenable to AER treatment are natural organic matter (NOM) and per- and polyfluoroalkyl substances (PFAS), specifically anionic perfluoroalkyl acids (PFAAs) such as perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). NOM is ubiquitous in natural waters and is often targeted for removal. PFAS occurrence in water resources is a human health concern. Accordingly, the goal of this research was to provide new insights on the use of AER for water treatment considering separate and combined removal of NOM and PFAAs. Batch experiments were conducted comparing polystyrene and polyacrylic AER in both chloride- and sulfate-forms using natural groundwater spiked with Suwannee River natural organic matter (SRNOM) and/or six PFAAs. The polymer composition of the AER had a significant impact on contaminant removal with polystyrene resin more effective for PFAA removal and polyacrylic resin more effective for SRNOM removal. Both resins had type I quaternary ammonium functional groups; however, the polyacrylic resin had trimethyl ammonium whereas the polystyrene resin had triethyl ammonium. Therefore, the influence of polymer composition could not be isolated conclusively from functional group chemistry. Polystyrene AER showed greater removal of PFAAs with sulfonate than carboxylate head group and 8-carbon than 4-carbon chain length. Removal of SRNOM and PFAAs by both resin polymer compositions were greater when sulfate was the mobile counterion ion than chloride. The results of this research have important implications for using AER for water treatment and remediation. Foremost, polymer composition and mobile counterion form of the resin can be selected to target specific contaminants and maximize contaminant removal. When contaminants have unique interactions with AER such as SRNOM and polyacrylic resin and PFAAs and polystyrene resin, the presence of one contaminant does not impact removal of the other contaminant.

Poly- and perfluoroalkyl substances (PFAS) are ubiquitous contaminants that can bioaccumulate in aquatic taxa. Amphibians are particularly vulnerable to contaminants and sensitive to endocrine disruptors during their aquatic larval stage. However, few studies have explored PFAS uptake rates in amphibians, which is critical for designing ecotoxicology studies and assessing the potential for bioaccumulation. Uptake rates of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were measured for larval northern leopard frogs (Rana pipiens), American toads (Anaxyrus americanus), and eastern tiger salamanders (Ambystoma tigrinum) during a 240-h exposure to 10 and 1000 μg/L concentrations. We measured body burden and calculated bioconcentration factor (BCF) every 48 h during the experiments. For all species and exposures, body burdens often reached steady state within 48–96 h of exposure. Steady-state body burdens for PFOA and PFOS ranged from 3819 to 16,481 ng/g dry weight (BCF = 0.46–2.5) and 6955–489,958 ng/g dry weight (47–259 BCFs), respectively. Therefore, PFAS steady state occurs rapidly in the larval amphibians we studied and particularly for PFOS. This result reflects a high potential for PFAS trophic transfer because amphibians are often low in trophic position and are important prey for many aquatic and terrestrial species.

Sphingosine-1-phosphate lyase (SPL) is an intracellular enzyme that controls the final step in the sphingolipid degradative pathway, the only biochemical pathway for removal of sphingolipids. Specifically, SPL catalyzes the cleavage of sphingosine 1-phosphate (S1P) at the C2-3 carbon bond, resulting in its irreversible degradation to phosphoethanolamine (PE) and hexadecenal. The substrate of the reaction, S1P, is a bioactive sphingolipid metabolite that signals through a family of five G protein-coupled S1P receptors (S1PRs) to mediate biological activities including cell migration, cell survival/death/proliferation and cell extrusion, thereby contributing to development, physiological functions and - when improperly regulated - the pathophysiology of disease. In 2017, several groups including ours reported a novel childhood syndrome that featured a wide range of presentations including fetal hydrops, steroid-resistant nephrotic syndrome (SRNS), primary adrenal insufficiency (PAI), rapid or insidious neurological deterioration, immunodeficiency, acanthosis and endocrine abnormalities. In all cases, the disease was attributed to recessive mutations in the human SPL gene, SGPL1. We now refer to this condition as SPL Insufficiency Syndrome, or SPLIS. Some features of this new sphingolipidosis were predicted by the reported phenotypes of Sgpl1 homozygous null mice that serve as vertebrate SPLIS disease models. However, other SPLIS features reveal previously unrecognized roles for SPL in human physiology. In this review, we briefly summarize the biochemistry, functions and regulation of SPL, the main clinical and biochemical features of SPLIS and what is known about the pathophysiology of this condition from murine and cell models. Lastly, we consider potential therapeutic strategies for the treatment of SPLIS patients.

Although the corazonin gene (Crz) has been molecularly characterized, little is known concerning the function of this neuropeptide in Drosophila melanogaster. To gain insight into Crz function in Drosophila, we have investigated the developmental regulation of Crz expression and the morphology of corazonergic neurons. From late embryo to larva, Crz expression is consistently detected in three neuronal groups: dorso-lateral Crz neurons (DL), dorso-medial Crz neurons (DM), and Crz neurons in the ventral nerve cord (vCrz). Both the vCrz and DM groups die via programmed cell death during metamorphosis, whereas the DL neurons persist to adulthood. In adults, Crz is expressed in a cluster of six to eight neurons per lobe in the pars lateralis (DLP), in numerous neuronal cells in the optic lobes, and in a novel group of four abdominal ganglionic neurons present only in males (ms-aCrz). The DLP group consists of two subsets of cells having different developmental origins: embryo and pupa. In the optic lobes, we have detected both Crz transcripts and Crz promoter activity, but no Crz-immunoreactive products, suggesting a post-transcriptional regulation of Crz mRNA. Projections of the ms-aCrz neurons terminate within the ventral nerve cord, implying a role as interneurons. Terminals of the DLP neurons are found in the retrocerebral complex that produces juvenile hormone and adipokinetic hormone. Significant reduction of trehalose levels in adults lacking DLP neurons suggests that DLP neurons are involved in the regulation of trehalose metabolism. Thus, the tissue-, stage-, and sex-specific expression of Crz and the association of Crz with the function of the retrocerebral complex suggest diverse roles for this neuropeptide in Drosophila.

To gain insight into regulatory mechanisms of tissue-specific Corazonin (Crz) gene expression and its functions in Drosophila, we cloned the Crz genes from four Drosophila species (D. melanogaster, D. simulans, D. erecta, and D. virilis) and performed comparative analyses of Crz gene sequences and expression patterns using in situ hybridization and immunohistochemistry. Although Crz gene sequences showed a great deal of diversity, its expression patterns in the CNS were highly conserved in the Drosophila species examined here. In D. melanogaster larva, Crz expression was found in four pairs of neurons per cerebral lobe and in eight pairs of bilateral neurons in the ventral nerve cord; in adult, the number of Crz-producing neurons increased to 6-8 in the pars lateralis of each brain lobe, whereas neurons in the ventral nerve cord were no longer detectable. Crz transcripts were also found in the optic lobes; however, these mRNAs do not seem to be translated. Such adult-like Crz expression patterns were established within 48 hours after pupation. Somata of Crz-neurons in the pars lateralis are located in the vicinity of terminals emanating from PDF-containing pacemaking neurons, indicating a functional connection between the two peptidergic nervous systems. A subset of Crz neurons coexpressed the period clock gene; however, normal Crz transcription was unaffected by central clockworks. Two pairs of ectopic Crz cells were detected in the adult brains of behaviorally arrhythmic Clock(Jrk) or cycle(02) mutants, suggesting that CLOCK and CYCLE proteins negatively regulate Crz transcription in a cell-specific manner.

Members of the mammalian tristetraprolin family of CCCH tandem zinc finger proteins can bind to certain AU-rich elements (AREs) in mRNAs, leading to their deadenylation and destabilization. Mammals express three or four members of this family, but Drosophila melanogaster and other insects appear to contain a single gene, Tis11. We found that recombinant Drosophila Tis11 protein could bind to ARE-containing RNA oligonucleotides with low nanomolar affinity. Remarkably, co-expression in mammalian cells with "target" RNAs demonstrated that Tis11 could promote destabilization of ARE-containing mRNAs and that this was partially dependent on a conserved C-terminal sequence resembling the mammalian NOT1 binding domain. Drosophila Tis11 promoted both deadenylation and decay of a target transcript in this heterologous cell system. We used chromosome deletion/duplication and P element insertion to produce two types of Tis11 deficiency in adult flies, both of which were viable and fertile. To address the hypothesis that Tis11 deficiency would lead to the abnormal accumulation of potential target transcripts, we analyzed gene expression in adult flies by deep mRNA sequencing. We identified 69 transcripts from 56 genes that were significantly up-regulated more than 1.5-fold in both types of Tis11-deficient flies. Ten of the up-regulated transcripts encoded probable proteases, but many other functional classes of proteins were represented. Many of the up-regulated transcripts contained potential binding sites for tristetraprolin family member proteins that were conserved in other Drosophila species. Tis11 is thus an ARE-binding, mRNA-destabilizing protein that may play a role in post-transcriptional gene expression in Drosophila and other insects.

Chemical stabilization is an in situ remediation method that uses inexpensive amendments to reduce contaminant availability in polluted soil. We tested the effects of several amendments (limestone, red-mud, and furnace slag) on the extractability of heavy metals, microbial activities, phytoavailability of soil metals (assessed using lettuce, Lactuca sativa L.), and availability of heavy metals in ingested soil to the human gastrointestinal system (assessed using the physiologically based extraction test). The application of soil amendments significantly decreased the amount of soluble and extractable heavy metals in the soil (p

The molecular basis of programmed cell death (PCD) of neurons during early metamorphic development of the central nervous system (CNS) in Drosophila melanogaster are largely unknown, in part owing to the lack of appropriate model systems. Here, we provide evidence showing that a group of neurons (vCrz) that express neuropeptide Corazonin (Crz)gene in the ventral nerve cord of the larval CNS undergo programmed death within 6 hours of the onset of metamorphosis. The death was prevented by targeted expression of caspase inhibitor p35, suggesting that these larval neurons are eliminated via a caspase-dependent pathway. Genetic and transgenic disruptions of ecdysone signal transduction involving ecdysone receptor-B (EcR-B) isoforms suppressed vCrz death, whereas transgenic re-introduction of either EcR-B1 or EcR-B2 isoform into the EcR-B-null mutant resumed normal death. Expression of reaperin vCrz neurons and suppression of vCrz-cell death in a reaper-null mutant suggest that reaper functions are required for the death,while no apparent role was found for hid or grim as a death promoter. Our data further suggest that diap1 does not play a role as a central regulator of the PCD of vCrz neurons. Significant delay of vCrz-cell death was observed in mutants that lack dronc or darkfunctions, indicating that formation of an apoptosome is necessary, but not sufficient, for timely execution of the death. These results suggest that activated ecdysone signaling determines precise developmental timing of the neuronal degeneration during early metamorphosis, and that subsequent reaper-mediated caspase activation occurs through a novel DIAP1-independent pathway.

Objectives: We investigated incidence rates to understand the nature of medication errors potentially introduced by utilizing a computerized physician order entry (CPOE) system in the three clinical phases of the medication process: prescription, administration, and documentation. Methods: Overt observations and chart reviews were employed at two surgical intensive care units of a 950-bed tertiary teaching hospital. Ten categories of highrisk drugs prescribed over a four-month period were noted and reviewed. Error definition and classifications were adapted from previous studies for use in the present research. Incidences of medication errors in the three phases of the medication process were analyzed. In addition, nurses’ responses to prescription errors were also assessed. Results: Of the 534 prescriptions issued, 286 (53.6%) included at least one error. The proportion of errors was 19.0% (58) of the 306 drug administrations, of which two-thirds were verbal orders classified as errors due to incorrectly entered prescriptions. Documentation errors occurred in 205 (82.7%) of 248 correctly performed administrations. When tracking incorrectly entered prescriptions, 93% of the errors were intercepted by nurses, but two-thirds of them were recorded as prescribed rather than administered. Conclusion: The number of errors occurring at each phase of the medication process was relatively high, despite long experience with a CPOE system. The main causes of administration errors and documentation errors were prescription errors and verbal order processes. To reduce these errors, hospital-level and unitlevel efforts toward a better system are needed.