Stress and Multiple Sclerosis - Systematic review and meta-analysis of the association with disease onset, relapse risk and disability progression.

OBJECTIVE: This systematic review and meta-analysis address the evidence on the association of psychological stressors with onset of multiple sclerosis, inflammatory disease activity (relapses or new disease activity on magnetic resonance imaging, MRI) and disability progression. METHODS: PubMed was searched from 1946 to 15 July 2022. Studies and certain stressors were selected when they assessed stressors independent from stress elicited by the disease process itself. Risk of bias was assessed by the CASP Case Control Study Checklist and the CASP Cohort Study Checklist. Normal-Normal Hierarchical Model (NNHM) for random-effects meta-analysis was used in the Bayesian framework. RESULTS: 30 studies reporting data from 26 cohorts reporting on 24.781 cases could be identified. Ten studies addressed stressors and MS disease onset showing a weak to modest effect of psychological stressors. A meta-analysis of three studies investigating diagnosed stress disorders and MS risk showed a 1.87-fold (CI 1.061 to 3.429) increased MS risk. Stress and MS relapse risk were addressed in 19 heterogeneous studies. Meta-analyses from two independent cohorts investigating the same military threat of a population showed a threefold increased risk for relapses in association with war (relapse rate: 3.0, CI 1.56 to 5.81). In addition, two studies confirmed an association of stressful life events and MRI activity. Three studies of stressors and disease progression were included indicating some effect on disease progression. CONCLUSIONS: Taken together studies indicate a minor to modest impact of psychological stressors on disease onset, inflammatory activity and progression of MS. Possible case-selection bias and lack of confounder analysis were present in many studies.

Sixty years of research on bracken fern (Pteridium spp.) toxins: Environmental exposure, health risks and recommendations for bracken fern control.

Bracken fern (Pteridium spp.) is a highly problematic plant worldwide due to its toxicity in combination with invasive properties on former farmland, in deforested areas and on disturbed natural habitats. The carcinogenic potential of bracken ferns has caused scientific and public concern for six decades. Its genotoxic effects are linked to illudane-type glycosides (ITGs), their aglycons and derivatives. Ptaquiloside is considered the dominating ITG, but with significant contributions from other ITGs. The present review aims to compile evidence regarding environmental pollution by bracken fern ITGs, in the context of their human and animal health implications. The ITG content in bracken fern exhibits substantial spatial, temporal, and chemotaxonomic variation. Consumption of bracken fern as food is linked to human gastric cancer but also causes urinary bladder cancers in bovines browsing on bracken. Genotoxic metabolites are found in milk and meat from bracken fed animals. ITG exposure may also take place via contaminated water with recent data pointing to concentrations at microgram/L-level following rain events. Airborne ITG-exposure from spores and dust has also been documented. ITGs may synergize with major biological and environmental carcinogens like papillomaviruses and Helicobacter pylori to induce cancer, revealing novel instances of chemical and biological co-carcinogenesis. Thus, the emerging landscape from six decades of bracken research points towards a global environmental problem with increasingly complex health implications.

Optic Nerve Sheath Viscoelastic Properties: Re-Examination of Biomechanical Behavior and Clinical Implications.

BACKGROUND: Meta-analyses show a variable relationship between optic nerve sheath diameter (ONSD) and the presence of raised intracranial pressure (ICP). Because optic nerve sheath (ONS) tissue can be deformed, it is possible that ONSD reflects not only the current ICP but also prior deforming biomechanical exposures. In this post hoc analysis of two published data sets, we characterize ONS Young's modulus (E, mechanical stress per unit of strain) and calculate threshold pressure for plastic deformation. METHODS: The authors of two previously published articles contributed primary data for these unique post hoc analyses. Human cadaveric ex vivo measurements of ONSD (n = 10) and luminal distending pressure (range 5 to 65 mm Hg) were used to calculate E and the threshold pressure for plastic deformation. Clinical in vivo measurements of ONSD and ICP during endotracheal tube suction from patients with traumatic brain injury (n = 15) were used to validate the ex vivo cadaveric findings. RESULTS: Ex vivo ONS estimate of E was 140 ± 1.3 mm Hg (mean ± standard error), with evidence of plastic deformation occurring with distending pressure at 45 mm Hg. Similar E (71 ± 10 mm Hg) was estimated in vivo with an average ICP of 34 ± 2 mm Hg. CONCLUSIONS: Ex vivo, ONS plastic deformation occurs at levels of pressure commonly seen in patients with raised ICP, leading to distortion of the ICP-ONSD relationship. This evidence of plastic deformation may illustrate why meta-analyses fail to identify a single threshold in ONSD associated with the presence of raised ICP. Future studies characterizing time-dependent viscous characteristics of the ONS will help determine the time course of ONS tissue biomechanical behavior.

In vivo phytotoxic effect of yttrium-oxide nanoparticles on the growth, uptake and translocation of tomato seedlings (Lycopersicon esculentum).

The potential toxicity and ecological risks of rare-earth nanoparticles in the environment have become a concern due to their widespread application and inevitable releases. The integration of hydroponics experiments, partial least squares structural equation modeling (PLS-SEM), and Transmission Electron Microscopy (TEM) were utilized to investigate the physiological toxicity, uptake and translocation of yttrium oxide nanoparticles (Y2O3 NPs) under different hydroponic treatments (1, 5, 10, 20, 50 and 100 mg·L-1 of Y2O3 NPs, 19.2 mg·L-1 Y(NO3)3 and control) in tomato (Lycopersicon esculentum) seedlings. The results indicated that Y2O3 NPs had a phytotoxic effect on tomato seedlings' germination, morphology, physiology, and oxidative stress. The Y2O3 NPs and soluble YIII reduced the root elongation, bud elongation, root activity, chlorophyll, soluble protein content and superoxide dismutase and accelerated the proline and malondialdehyde in the plant with increasing concentrations. The phytotoxic effects of Y2O3 NPs on tomato seedlings had a higher phytotoxic effect than soluble YIII under the all treatments. The inhibition rates of different levels of Y2O3 NPs in shoot and root biomass ranged from 0.2% to 6.3% and 1.0-11.3%, respectively. The bioaccumulation and translocation factors were less than 1, which suggested that Y2O3 NPs significantly suppressed shoot and root biomass of tomato seedlings and easily bioaccumulated in the root. The observations were consistent with the process of concentration-dependent uptake and translocation factor and confirmed by TEM. Y2O3 NPs penetrate the epidermis, enter the cell wall, and exist in the intercellular space and cytoplasm of mesophyll cells of tomato seedlings by endocytic pathway. Moreover, PLS-SEM revealed that the concentration of NPs significantly negatively affects the morphology and physiology, leading to the change in biomass of plants. This study demonstrated the possible pathway of Y2O3 NPs in uptake, phytotoxicity and translocation of Y2O3 NPs in tomato seedlings.

Does sulfur application continue to reduce cadmium accumulation and increase the seed yield of oilseed rape (Brassica napus L.) at the maturity stage?

BACKGROUND: Oilseed rape requires sulfur (S) fertilization. Cadmium (Cd) differs dramatically in agricultural soils. Rice-oilseed rape rotation distributes widely and contributes the majority of rapeseeds in Asian countries. It was reported that S metabolism was involved in Cd uptake in seedlings of oilseed rape, although the effects of S on Cd accumulation and seed yield at maturity are still unclear. RESULTS: We performed a pot experiment including two Cd rates (0.35 and 10.35 mg kg-1 , as low and high Cd soil) and four S levels (0, 30, 60 and 120 mg kg-1 ). The results showed that low S application (30 mg kg-1 ) resulted in two-fold higher seed-Cd concentration irrespective of soil Cd levels. The responsible mechanism might be that Cd translocation into rapeseeds was involved in sulfate transporters, which could be strongly expressed in shoots and roots when supplying sulfate under S-starvation conditions, but depressed under a S-sufficient environment. For high Cd soil, seed yield decreased by 36%, 48% and 72% at 30, 60 and 120 mg S kg-1 compared to non-S treatment, whereas there were no differences for low Cd soil. Antagonistic effects of S and Cd existed for seed yield according to structure equation model analysis. CONCLUSION: Oilseed rape can be grown in low-Cd fields as a safe food crop with high levels of sulfur fertilizers (>60 mg S kg-1 ). In high-Cd fields, oilseed rape is recommended as a Cd-remediation crop, and rapeseeds should only be used for industrial purposes and not for food. © 2021 Society of Chemical Industry.

Bone Char Mediated Dechlorination of Trichloroethylene by Green Rust.

Biochars function as electron transfer mediators and thus catalyze redox transformations of environmental pollutants. A previous study has shown that bone char (BC) has high catalytic activity for reduction of chlorinated ethylenes using layered Fe(II)-Fe(III) hydroxide (green rust) as reductant. In the present study, we studied the rate of trichloroethylene (TCE) reduction by green rust in the presence of BCs obtained at pyrolysis temperatures (PTs) from 450 to 1050 °C. The reactivity increased with PT, yielding a maximum pseudo-first-order rate constant (k) of 2.0 h-1 in the presence of BC pyrolyzed at 950 °C, while no reaction was seen for BC pyrolyzed at 450 °C. TCE sorption, specific surface area, extent of graphitization, carbon content, and aromaticity of the BCs also increased with PT. The electron-accepting capacity (EAC) of BC peaked at PT of 850 °C, and EAC was linearly correlated with the sum of concentrations of quinoid, quaternary N, and pyridine-N-oxide groups measured by XPS. Moreover, no TCE reduction was seen with graphene nanoparticles and graphitized carbon black, which have high degrees of graphitization but low EAC values. Further analyses showed that TCE reduction rates are well correlated with the EAC and the C/H ratio (proxy of electrical conductivity) of the BCs, strongly indicating that both electron-accepting functional groups and electron-conducting domains are crucial for the BC catalytic reactivity. The present study delineates conditions for designing redox-reactive biochars to be used for remediation of sites contaminated with chlorinated solvents.

A Silicate/Glycine Switch To Control the Reactivity of Layered Iron(II)-Iron(III) Hydroxides for Dechlorination of Carbon Tetrachloride.

Layered FeII-FeIII hydroxide chloride (chloride green rust, GRCl) has high reactivity toward reducible pollutants such as chlorinated solvents. However, this reactive solid is prone to dissolution, and hence loss of reactivity, during storage and handling. In this study, adsorption of silicate (Si) to GRCl was tested for its ability to minimize GRCl dissolution and to inhibit reduction of carbon tetrachloride (CT). Silicate adsorbed with high affinity to GRCl yielding a sorption maximum of 0.026 g of Si/g of GRCl. In the absence of Si, the pseudo-first-order rate constant for CT dehalogenation by GRCl was 2.1 h-1, demonstrating very high reactivity of GRCl but with substantial FeII dissolution up to 2.5 mM. When Si was adsorbed to GRCl, CT dehalogenation was blocked and FeII dissolution extent was reduced by a factor of 28. The addition of glycine (Gly) was tested for reactivation of the Si-blocked GRCl for CT dehalogenation. At 30 mM Gly, partial reactivation of the GRCl was observed with pseudo-first-order rate constant for CT reduction of 0.075 h-1. This blockage and reactivation of GRCl reactivity demonstrates that it is possible to design a switch for GRCl to control its stability and reactivity under anoxic conditions.

Amino Acid-Assisted Dehalogenation of Carbon Tetrachloride by Green Rust: Inhibition of Chloroform Production.

Layered FeII-FeIII hydroxides (green rusts, GRs) are promising reactants for reductive dechlorination of chlorinated solvents due to high reaction rates and the opportunity to inject reactive slurries of the compounds into contaminant plumes. However, it is necessary to develop strategies that reduce the formation of toxic byproducts such as chloroform (CF). In this study, carbon tetrachloride (CT) dehalogenation by the chloride form of GR (GRCl) was tested in the presence of glycine (GLY) and other selected amino acids. GLY, alanine (ALA), and serine (SER) all resulted in remarkable suppression of CF formation with only ∼10% of CF recovery while sarcosine (SAR) showed insignificant effects. For two nonamino acid buffers, TRIS had little effect while HEPES resulted in a 40 times lower rate constant compared to experiments in which no buffer was added. The FeII complexing properties of the amino acids and buffers caused variable extents of GRCl dissolution which was linearly correlated with CF suppression and dehalogenation rate. We hypothesize that the CF suppression seen for amino acids is caused by stabilization of carbene intermediates via the carbonyl group. Different effects on CF suppression and CT dehalogenation rate were expected because of the different structural and chemical properties of the amino acids.

UPLC-MS/MS determination of ptaquiloside and pterosin B in preserved natural water.

The naturally occurring carcinogen ptaquiloside and its degradation product pterosin B are found in water leaching from bracken stands. The objective of this work is to present a new sample preservation method and a fast UPLC-MS/MS method for quantification of ptaquiloside and pterosin B in environmental water samples, employing a novel internal standard. A faster, reliable, and efficient method was developed for isolation of high purity ptaquiloside and pterosin B from plant material for use as analytical standards, with purity verified by 1H-NMR. The chemical analysis was performed by cleanup and preconcentration of samples with solid phase extraction, before analyte quantification with UPLC-MS/MS. By including gradient elution and optimizing the liquid chromatography mobile phase buffer system, a total run cycle of 5 min was achieved, with method detection limits, including preconcentration, of 8 and 4 ng/L for ptaquiloside and pterosin B, respectively. The use of loganin as internal standard improved repeatability of the determination of both analytes, though it could not be employed for sample preparation. Buffering raw water samples in situ with ammonium acetate to pH ∼5.5 decisively increased sample integrity at realistic transportation and storing conditions prior to extraction. Groundwater samples collected in November 2015 at the shallow water table below a Danish bracken stand were preserved and analyzed using the above methods, and PTA concentrations of 3.8 ± 0.24 µg/L (±sd, n = 3) were found, much higher than previously reported. Graphical abstract Workflow overview of ptaquiloside determination.

Suspended particles only marginally reduce pyrethroid toxicity to the freshwater invertebrate Gammarus pulex (L.) during pulse exposure.

Current ecotoxicological research on particle-associated pyrethroids in freshwater systems focuses almost exclusively on sediment-exposure scenarios and sediment-dwelling macroinvertebrates. We studied how suspended particles influence acute effects of lambda-cyhalothrin and bifenthrin on the epibenthic freshwater amphipod Gammarus pulex (L.) using brief pulse exposures followed by a 144 h post exposure recovery phase. Humic acid (HA) and the clay mineral montmorillonite (MM) were used as model sorbents in environmentally realistic concentrations (5, 25 and 125 mg L(-1)). Mortality of G. pulex was recorded during the post exposure recovery phase and locomotor behavior was measured during exposure to lambda-cyhalothrin. We found that HA in concentrations ≥25 mg L(-1) adsorbed the majority of pyrethroids but only reduced mortality of G. pulex up to a factor of four compared to pyrethroid-only treatments. MM suspensions adsorbed a variable fraction of pyrethroids (10% for bifenthrin and 70% for lambda-cyhalothrin) but did not significantly change the concentration-response relationship compared to pure pyrethroid treatments. Behavioral responses and immobilisation rate of G. pulex were reduced in the presence of HA, whereas behavioral responses and immobilisation rate were increased in the presence of MM. This indicates that G. pulex was capable of sensing the bioavailable fraction of lambda-cyhalothrin. Our results imply that suspended particles reduce to only a limited extent the toxicity of pyrethroids to G. pulex and that passive uptake of pyrethroids can be significant even when pyrethroids are adsorbed to suspended particles.

Ptaquiloside in Irish Bracken Ferns and Receiving Waters, with Implications for Land Managers.

Ptaquiloside, along with other natural phytotoxins, is receiving increased attention from scientists and land use managers. There is an urgent need to increase empirical evidence to understand the scale of phytotoxin mobilisation and potential to enter into the environment. In this study the risk of ptaquiloside to drinking water was assessed by quantifying ptaquiloside in the receiving waters at three drinking water abstraction sites across Ireland and in bracken fronds surrounding the abstraction sites. We also investigated the impact of different management regimes (spraying, cutting and rolling) on ptaquiloside concentrations at plot-scale in six locations in Northern Ireland, UK. Ptaquiloside concentrations were determined using recent advances in the use of LC-MS for the detection and quantification of ptaquiloside. The results indicate that ptaquiloside is present in bracken stands surrounding drinking water abstractions in Ireland, and ptaquiloside concentrations were also observed in the receiving waters. Furthermore, spraying was found to be the most effective bracken management regime observed in terms of reducing ptaquiloside load. Increased awareness is vital on the implications of managing land with extensive bracken stands.

Land management of bracken needs to account for bracken carcinogens--a case study from Britain.

Bracken ferns are some of the most widespread ferns in the World causing immense problems for land managers, foresters and rangers. Bracken is suspected of causing cancer in Humans due to its content of the carcinogen ptaquiloside. Ingestion of bracken, or food and drinking water contaminated with ptaquiloside may be the cause. The aim of this study was to monitor the content of ptaquiloside in 20 bracken stands from Britain to obtain a better understanding of the ptaquiloside dynamics and to evaluate the environmental implications of using different cutting regimes in bracken management. The ptaquiloside content in fronds ranged between 50 and 5790 µg/g corresponding to a ptaquiloside load in the standing biomass of up to 590 mg/m(2) in mature fronds. Ptaquiloside was also found in the underground rhizome system (11-657 µg/g) and in decaying litter (0.1-5.8 µg/g). The amount of ptaquiloside present in bracken stands at any given time is difficult to predict and did not show any correlations with edaphic growth factors. The content of ptaquiloside turned out to be higher in fronds emerging after cutting compared to uncut fronds. Environmental risk assessment and bracken management must therefore be based on actual and site specific determinations of the ptaquiloside content. Care must be taken to avoid leaching from cut ferns to aquifers and other recipients and appropriate precautionary measures must be taken to protect staff from exposure to bracken dust.

Novel small molecule inhibitors of TLR7 and TLR9: mechanism of action and efficacy in vivo.

The discovery that circulating nucleic acid-containing complexes in the serum of autoimmune lupus patients can stimulate B cells and plasmacytoid dendritic cells via Toll-like receptors 7 and 9 suggested that agents that block these receptors might be useful therapeutics. We identified two compounds, AT791 {3-[4-(6-(3-(dimethylamino)propoxy)benzo[d]oxazol-2-yl)phenoxy]-N,N-dimethylpropan-1-amine} and E6446 {6-[3-(pyrrolidin-1-yl)propoxy)-2-(4-(3-(pyrrolidin-1-yl)propoxy)phenyl]benzo[d]oxazole}, that inhibit Toll-like receptor (TLR)7 and 9 signaling in a variety of human and mouse cell types and inhibit DNA-TLR9 interaction in vitro. When administered to mice, these compounds suppress responses to challenge doses of cytidine-phosphate-guanidine (CpG)-containing DNA, which stimulates TLR9. When given chronically in spontaneous mouse lupus models, E6446 slowed development of circulating antinuclear antibodies and had a modest effect on anti-double-stranded DNA titers but showed no observable impact on proteinuria or mortality. We discovered that the ability of AT791 and E6446 to inhibit TLR7 and 9 signaling depends on two properties: weak interaction with nucleic acids and high accumulation in the intracellular acidic compartments where TLR7 and 9 reside. Binding of the compounds to DNA prevents DNA-TLR9 interaction in vitro and modulates signaling in vivo. Our data also confirm an earlier report that this same mechanism may explain inhibition of TLR7 and 9 signaling by hydroxychloroquine (Plaquenil; Sanofi-Aventis, Bridgewater, NJ), a drug commonly prescribed to treat lupus. Thus, very different structural classes of molecules can inhibit endosomal TLRs by essentially identical mechanisms of action, suggesting a general mechanism for targeting this group of TLRs.

Therapeutical targeting of nucleic acid-sensing Toll-like receptors prevents experimental cerebral malaria.

Excessive release of proinflammatory cytokines by innate immune cells is an important component of the pathogenic basis of malaria. Proinflammatory cytokines are a direct output of Toll-like receptor (TLR) activation during microbial infection. Thus, interference with TLR function is likely to render a better clinical outcome by preventing their aberrant activation and the excessive release of inflammatory mediators. Herein, we describe the protective effect and mechanism of action of E6446, a synthetic antagonist of nucleic acid-sensing TLRs, on experimental cerebral malaria (ECM) induced by Plasmodium berghei ANKA. We show that in vitro, low doses of E6446 specifically inhibited the activation of human and mouse TLR9. Tenfold higher concentrations of this compound also inhibited the human TLR8 response to single-stranded RNA. In vivo, therapy with E6446 diminished the activation of TLR9 and prevented the exacerbated cytokine response observed during acute Plasmodium infection. Furthermore, severe signs of ECM, such as limb paralysis, brain vascular leak, and death, were all prevented by oral treatment with E6446. Hence, we provide evidence that supports the involvement of nucleic acid-sensing TLRs in malaria pathogenesis and that interference with the activation of these receptors is a promising strategy to prevent deleterious inflammatory responses that mediate pathogenesis and severity of malaria.

Phosphate sorption by three potential filter materials as assessed by isothermal titration calorimetry.

Phosphorus eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of phosphate (P) sorbing filters at drain outlets may be a solution. The aim of this study was to improve the understanding of reactions involved in P sorption by three commercial P sorbing materials, i.e. Ca/Mg oxide-based Filtralite-P, Fe oxide-based CFH-12 and Limestone in two particle sizes (2-1 mm and 1-0.5 mm), by means of isothermal titration calorimetry (ITC), sorption isotherms, sequential extractions and SEM-EDS. The results indicate that P retention by CFH is due to surface complexation by rapid formation of strong Fe-P bonds. In contrast, retention of P by Filtralite-P and Limestone strongly depends on pH and time and is interpreted due to formation of calcium phosphate precipitate(s). Consequently, CFH can unambiguously be recommended as P retention filter material in drain outlets, whereas the use of Filtralite-P and Limestone has certain (serious) limitations. Thus, Filtralite-P has high capacity to retain P but only at alkaline pH (pH ≥ 10) and P retention by Limestone requires long-time contact and a high ratio between sorbent and sorbate.

Modeling the environmental fate of bracken toxin ptaquiloside: Production, release and transport in the rhizosphere.

Plants produce a diverse array of toxic compounds which may be released by precipitation, explaining their wide occurrence in surrounding soil and water. This study presents the first mechanistic model for describing the generation and environmental fate of a natural toxin, i.e. ptaquiloside (PTA), a carcinogenic phytotoxin produced by bracken fern (Pteridium aquilinum L. Kuhn). The newly adapted DAISY model was calibrated based on two-year monitoring performed in the period 2018-2019 in a Danish bracken population located in a forest glade. Several functions related to the fate of PTA were calibrated, covering processes from toxin generation in the canopy, wash off by precipitation and degradation in the soil. Model results show a good description of observed bracken biomass and PTA contents, supporting the assumption that toxin production can be explained by the production of new biomass. Model results show that only 4.4 % of the PTA produced in bracken is washed off by precipitation, from both canopy and litter. Model simulations showed that PTA degrades rapidly once in the soil, especially during summer due to the high soil temperatures. Leaching takes place in form of pulses directly connected to precipitation events, with maximum simulated concentrations up to 4.39 µg L-1 at 50 cm depth. Macropore transport is mainly responsible for the events with the highest PTA concentrations, contributing to 72 % of the total mass of PTA leached. Based on the results, we identify areas with high density of bracken, high precipitation during the summer and soils characterized by fast transport, as the most vulnerable to surface and groundwater pollution by phytotoxins.

Fast degradation of vinyl chloride by green rust and nitrogen-doped graphene.

Carbonaceous materials catalyze reductive dechlorination of chlorinated ethylenes (CEs) by iron(II) materials providing a new approach for the remediation of CE polluted groundwater. While most CEs are reduced via ß-elimination, vinyl chloride (VC), the most toxic and recalcitrant CE, degrades by hydrogenolysis. The significance of carbon catalysts for reduction of VC is well documented for iron(0) systems, but hardly investigated with iron(II) materials as reductants. In this study, a layered iron(II)­iron(III) hydroxide sulfate (green rust) was used as reductant for VC, with an N-doped graphene (NG), prepared by co-pyrolysis of graphene and urea, as catalyst. VC (80 µM) was completely reduced to ethylene within 336 h in the presence of 5 g Fe/L GR and 5 g/L NG pyrolyzed at 950 °C, following pseudo-first-order kinetics with a rate constant of 0.017 h-1. Dosing experiments demonstrated that dechlorination of VC takes place on the NG phase. Monitoring of hydrogen formation, cyclic voltammetry, and quenching experiments demonstrated that atomic hydrogen contributes significantly to the dehalogenation reaction, where NG is critical for formation of atomic hydrogen. CE competition experiments demonstrated the presence of specific VC reduction sites with hydrogenolysis being unaffected by concurrent ß-elimination reactions. The system exhibited excellent performance in natural groundwaters and in comparison with iron(0) systems. This study demonstrates that GR + NG is a promising system for remediation of VC contaminated groundwater, and the mechanistic part of the study can be used as a reference for subsequent studies.

The Delphi Delirium Management Algorithms. A practical tool for clinicians, the result of a modified Delphi expert consensus approach.

Delirium is common in hospitalised patients, and there is currently no specific treatment. Identifying and treating underlying somatic causes of delirium is the first priority once delirium is diagnosed. Several international guidelines provide clinicians with an evidence-based approach to screening, diagnosis and symptomatic treatment. However, current guidelines do not offer a structured approach to identification of underlying causes. A panel of 37 internationally recognised delirium experts from diverse medical backgrounds worked together in a modified Delphi approach via an online platform. Consensus was reached after five voting rounds. The final product of this project is a set of three delirium management algorithms (the Delirium Delphi Algorithms), one for ward patients, one for patients after cardiac surgery and one for patients in the intensive care unit.

Optic disc edema in an astronaut after repeat long-duration space flight.

BACKGROUND: A number of ophthalmic findings including optic disc edema, globe flattening, and choroidal folds have been observed in several astronauts after long-duration space flights. The authors report the first astronaut with previously documented postflight ophthalmic abnormalities who developed new pathological changes after a repeat long-duration mission. METHODS: A case study of an astronaut with 2 long-duration (6 months) exposures to microgravity. Before and after his first long-duration space flight, he underwent complete eye examination, including fundus photography. Before and after his second flight, 9 years later, he underwent fundus photography, optical coherence tomography, ocular ultrasonography, and brain magnetic resonance imaging, as well as in-flight fundus photography and ultrasound. RESULTS: After his first long-duration mission, the astronaut was documented to have eye findings limited to unilateral choroidal folds and a single cotton wool spot. During a subsequent 6-month mission, he developed more widespread choroidal folds and new onset of optic disc edema in the same eye. CONCLUSION: Microgravity-induced anatomical changes that occurred during the first mission may have set the stage for recurrent or additional changes when the astronaut was subjected to physiological stress of repeat space flight.

Degradation of chlorpyrifos in humid tropical soils.

The insecticide chlorpyrifos is extensively used in the humid tropics for insect control on crops and soils. Chlorpyrifos degradation and mineralization was studied under laboratory conditions to characterize the critical factors controlling the degradation and mineralization in three humid tropical soils from Malaysia. The degradation was fastest in moist soils (t1/2 53.3-77.0 days), compared to dry (t1/2 49.5-120 days) and wet soils (t1/2 63.0-124 days). Degradation increased markedly with temperature with activation energies of 29.0-76.5 kJ mol(-1). Abiotic degradation which is important for chlorpyrifos degradation in sub-soils containing less soil microbial populations resulted in t½ of 173-257 days. Higher chlorpyrifos dosages (5-fold) which are often applied in the tropics due to severe insects infestations caused degradation and mineralization rates to decrease by 2-fold. The mineralization rates were more sensitive to the chlorpyrifos application rates reflecting that degradation of metabolites is rate limiting and the toxic effects of some of the metabolites produced. Despite that chlorpyrifos is frequently used and often in larger amounts on tropical soils compared with temperate soils, higher temperature, moderate moisture and high activity of soil microorganisms will stimulate degradation and mineralization.