A detailed understanding of the formation of the potent neurotoxic methylmercury is needed to explain the large observed variability in methylmercury levels in aquatic systems. While it is known that ...organic matter interacts strongly with mercury, the role of organic matter composition in the formation of methylmercury in aquatic systems remains poorly understood. Here we show that phytoplankton-derived organic compounds enhance mercury methylation rates in boreal lake sediments through an overall increase of bacterial activity. Accordingly, in situ mercury methylation defines methylmercury levels in lake sediments strongly influenced by planktonic blooms. In contrast, sediments dominated by terrigenous organic matter inputs have far lower methylation rates but higher concentrations of methylmercury, suggesting that methylmercury was formed in the catchment and imported into lakes. Our findings demonstrate that the origin and molecular composition of organic matter are critical parameters to understand and predict methylmercury formation and accumulation in boreal lake sediments.
Monomethylmercury (MeHg) in fish from freshwater, estuarine, and marine environments is a major global environmental issue. Mercury levels in biota are mainly controlled by the methylation of ...inorganic mercuric mercury (HgII) to MeHg in water, sediments, and soils. There is, however, a knowledge gap concerning the mechanisms and rates of methylation of specific geochemical HgII species. Such information is crucial for a better understanding of variations in MeHg concentrations among ecosystems and, in particular, for predicting the outcome of currently proposed measures to mitigate mercury emissions and reduce MeHg concentrations in fish. To fill this knowledge gap we propose an experimental approach using HgII isotope tracers, with defined and geochemically important adsorbed and solid HgII forms in sediments, to study MeHg formation. We report HgII methylation rate constants, k m , in estuarine sediments which span over 2 orders of magnitude depending on chemical form of added tracer: metacinnabar (β-201HgS(s)) < cinnabar (α-199HgS(s)) < HgII reacted with mackinawite (≡FeS-202HgII) < HgII bonded to natural organic matter (NOM-196HgII) < a typical aqueous tracer (198Hg(NO3)2(aq)). We conclude that a combination of thermodynamic and kinetic effects of HgII solid-phase dissolution and surface desorption control the HgII methylation rate in sediments and cause the large observed differences in k m -values. The selection of relevant solid-phase and surface-adsorbed HgII tracers will therefore be crucial to achieving biogeochemically accurate estimates of ambient HgII methylation rates.
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The Swedish Agency for Health Technology Assessment and Assesment of Social Services (SBU) is an independent national authority, tasked by the government with assessing methods used in health, ...medical and dental services and social service interventions from a broad perspective, covering medical, economic, ethical and social aspects.
The language in SBU's reports are adjusted to a wide audience.
SBU's Board of Directors has approved the conclusions in this report.
The systematic review showed the following graded results:
There is limited scientific evidence that the triad (Three components of a whole. The triad associated with SBS usually comprises subdural haematoma, retinal haemorrhages and encephalopathy.) and therefore, its components can be associated with traumatic shaking (low‐quality evidence).
There is insufficient scientific evidence on which to assess the diagnostic accuracy of the triad in identifying traumatic shaking (very low‐quality evidence).
Limited scientific evidence (low‐quality evidence) represents a combined assessment of studies of high or moderate quality which disclose factors that markedly weaken the evidence. It is important to note that limited scientific evidence for the reliability of a method or an effect does not imply complete lack of scientific support.
Insufficient scientific evidence (very low‐quality evidence) represents either a lack of studies or situations when available studies are of low quality or show contradictory results. Evaluation of the evidence was not based on formal grading of the evidence according to GRADE but on an evaluation of the total scientific basis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Antiretroviral treatment history and past HIV-1 genotypes have been shown to be useful predictors for the success of antiretroviral therapy. However, this information may be unavailable or ...inaccurate, particularly for patients with multiple treatment lines often attending different clinics. We trained statistical models for predicting drug exposure from current HIV-1 genotype. These models were trained on 63,742 HIV-1 nucleotide sequences derived from patients with known therapeutic history, and on 6,836 genotype-phenotype pairs (GPPs). The mean performance regarding prediction of drug exposure on two test sets was 0.78 and 0.76 (ROC-AUC), respectively. The mean correlation to phenotypic resistance in GPPs was 0.51 (PhenoSense) and 0.46 (Antivirogram). Performance on prediction of therapy-success on two test sets based on genetic susceptibility scores was 0.71 and 0.63 (ROC-AUC), respectively. Compared to geno2phenoresistance, our novel models display a similar or superior performance. Our models are freely available on the internet via www.geno2pheno.org. They can be used for inferring which drug compounds have previously been used by an HIV-1-infected patient, for predicting drug resistance, and for selecting an optimal antiretroviral therapy. Our data-driven models can be periodically retrained without expert intervention as clinical HIV-1 databases are updated and therefore reduce our dependency on hard-to-obtain GPPs.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Building Information Modelling (BIM) is widely seen as a catalyst for innovation and productivity in the construction industry. BIM can assist a more sustainable construction process that in turn may ...contribute to eradicating poverty in developing countries (United Nation Millennium Goals). While BIM is increasingly being adopted in developed countries, implementations in the developing country context are rare. Research has established how construction firms struggle from several limitations having to do with the socio-economic and technological environment found in developing countries. Examples of issues preventing BIM adoption include a shortage of IT-literate personnel as well as an absence of national BIM implementation programs. Based on a review of recent research, this article addresses some of the hurdles and solutions for BIM implementations particular to low- and middle-income economies. Findings include that developing countries’ construction firms rely on outsourcing of IT services or developing tweaks or workarounds, like using ‘fake’ IT licenses, for saving cost and enabling BIM. The article highlights shortcomings of existing research on BIM implementation in developing countries, and may serve as a starting point for researchers interested in how BIM technology can be adopted in a developing country context.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Final harvest (clear-cutting) of coniferous boreal forests has been shown to increase streamwater concentrations and export of the neurotoxin methyl mercury (MeHg) to freshwater ecosystems. Here, the ...spatial distribution of inorganic Hg and MeHg in soil as a consequence of clear-cutting is reported. A comparison of soils at similar positions along hillslopes in four 80 years old Norway spruce (Picea abies) stands (REFs) with those in four similar stands subjected to clear-cutting (CCs) revealed significantly (p < 0.05) enhanced MeHg concentrations (ng g–1), MeHg areal masses (g ha–1), and percent MeHg of HgTOT in O horizons of CCs located between 1 and 41 m from streams. Inorganic Hg measures did not differ between REFs and CCs at any position. The O horizon thickness did not differ between CCs and REFs, but the groundwater table and soil water content were significantly higher at CCs than at REFs. The largest difference in percent MeHg of HgTOT (12 times higher at CCs compared to REFs, p = 0.003) was observed in concert with a significant enhancement in soil water content (p = 0.0003) at intermediate hillslope positions (20−38 m from stream), outside the stream riparian zone. Incubation experiments demonstrated that soils having significantly enhanced soil pools of MeHg after clear-cutting also showed significantly enhanced methylation potential as compared with similarly positioned soils in mature reference stands. The addition of inhibitors demonstrated that sulfate-reducing bacteria (SRB) and methanogens were key methylators. Rates of demethylation did not differ between CCs and REFs. Our results suggest that enhanced water saturation of organic soils providing readily available electron donors stimulate Hg-methylating microbes to net formation and buildup of MeHg in O horizons after forest harvest.
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Epoxies are often cured using primary and secondary amines in an efficient reaction catalyzed by tertiary amines. Through coordination effects, tertiary amines lower the transition-state energy ...enough to allow the reaction to take place under ambient conditions. In this paper, we demonstrate how, under ambient conditions, tertiary amines bound in close intramolecular proximity to a primary amine are able to catalyze amine-epoxy reactions as well as promote etherifications in epoxy-rich systems. 13C nuclear magnetic resonance (NMR) was used to identify the sequence of curing reactions in a model reaction of benzyl glycidyl ether (BGE) with the amines 3-diethylaminopropylamine (DEAPA), 3-dimethylaminopropylamine (DMAPA), and hexylamine, respectively. The results clearly show that DMAPA favors etherification over amine-epoxy reactions, while DEAPA displays the expected trend toward amine-epoxy reactions. This experiment was repeated for a curing epoxy system based on bisphenol A diglycidylether (BADGE) with the same three amines, and differential scanning calorimetry (DSC) confirmed this preference of reactions via quantification of the curing exotherms. Finally, a novel DMA setup corroborated the observed rate of reaction for each catalyst by measuring gelation time and vitrification during isothermal curing.
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Abstract
The most critical step for methylmercury (MeHg) bioaccumulation in aquatic food webs is phytoplankton uptake of dissolved MeHg. Dissolved organic matter (DOM) has been known to influence ...MeHg uptake, but the mechanisms have remained unclear. Here we show that the concentration of DOM-associated thiol functional groups (DOM-RSH) varies substantially across contrasting aquatic systems and dictates MeHg speciation and bioavailability to phytoplankton. Across our 20 study sites, DOM-RSH concentrations decrease 40-fold from terrestrial to marine environments whereas dissolved organic carbon (DOC), the typical proxy for MeHg binding sites in DOM, only has a 5-fold decrease. MeHg accumulation into phytoplankton is shown to be directly linked to the concentration of specific MeHg binding sites (DOM-RSH), rather than DOC. Therefore, MeHg bioavailability increases systematically across the terrestrial-marine aquatic continuum as the DOM-RSH concentration decreases. Our results strongly suggest that measuring DOM-RSH concentrations will improve empirical models in phytoplankton uptake studies and will form a refined basis for modeling MeHg incorporation in aquatic food webs under various environmental conditions.
Neurotoxic methylmercury (MeHg) is formed by microbial methylation of inorganic divalent Hg (HgII) and constitutes severe environmental and human health risks. The methylation is enabled by hgcA and ...hgcB genes, but it is not known if the associated molecular-level processes are rate-limiting or enable accurate prediction of MeHg formation in nature. In this study, we investigated the relationships between hgc genes and MeHg across redox-stratified water columns in the brackish Baltic Sea. We showed, for the first time, that hgc transcript abundance and the concentration of dissolved HgII-sulfide species were strong predictors of both the HgII methylation rate and MeHg concentration, implying their roles as principal joint drivers of MeHg formation in these systems. Additionally, we characterized the metabolic capacities of hgc + microorganisms by reconstructing their genomes from metagenomes (i.e., hgc + MAGs), which highlighted the versatility of putative HgII methylators in the water column of the Baltic Sea. In establishing relationships between hgc transcripts and the HgII methylation rate, we advance the fundamental understanding of mechanistic principles governing MeHg formation in nature and enable refined predictions of MeHg levels in coastal seas in response to the accelerating spread of oxygen-deficient zones.
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Background and purpose
During acute coronavirus disease 2019 (COVID‐19) infection, neurological signs, symptoms and complications occur. We aimed to assess their clinical relevance by evaluating ...real‐world data from a multinational registry.
Methods
We analyzed COVID‐19 patients from 127 centers, diagnosed between January 2020 and February 2021, and registered in the European multinational LEOSS (Lean European Open Survey on SARS‐Infected Patients) registry. The effects of prior neurological diseases and the effect of neurological symptoms on outcome were studied using multivariate logistic regression.
Results
A total of 6537 COVID‐19 patients (97.7% PCR‐confirmed) were analyzed, of whom 92.1% were hospitalized and 14.7% died. Commonly, excessive tiredness (28.0%), headache (18.5%), nausea/emesis (16.6%), muscular weakness (17.0%), impaired sense of smell (9.0%) and taste (12.8%), and delirium (6.7%) were reported. In patients with a complicated or critical disease course (53%) the most frequent neurological complications were ischemic stroke (1.0%) and intracerebral bleeding (ICB; 2.2%). ICB peaked in the critical disease phase (5%) and was associated with the administration of anticoagulation and extracorporeal membrane oxygenation (ECMO). Excessive tiredness (odds ratio OR 1.42, 95% confidence interval CI 1.20–1.68) and prior neurodegenerative diseases (OR 1.32, 95% CI 1.07–1.63) were associated with an increased risk of an unfavorable outcome. Prior cerebrovascular and neuroimmunological diseases were not associated with an unfavorable short‐term outcome of COVID‐19.
Conclusion
Our data on mostly hospitalized COVID‐19 patients show that excessive tiredness or prior neurodegenerative disease at first presentation increase the risk of an unfavorable short‐term outcome. ICB in critical COVID‐19 was associated with therapeutic interventions, such as anticoagulation and ECMO, and thus may be an indirect complication of a life‐threatening systemic viral infection.
We retrospectively analyzed data from 6537 predominantly hospitalized COVID‐19 patients registered in the European multinational Lean European Open Survey on SARS‐Infected Patients (LEOSS) registry between January 2020 and February 2021. Common neurological symptoms were excessive tiredness (28.0%), headache (18.5%), nausea/emesis (16.6%), muscular weakness (17.0%), impaired sense of smell (9.0%) and taste (12.8%), and delirium (6.7%). Most frequent neurological complications were ischemic stroke (1.0%) and intracerebral bleeding (2.2%) in patients with a complicated or critical disease course. Excessive tiredness (odds ratio OR 1.42) and prior neurodegenerative disease (OR 1.32) were associated with an increased risk of an unfavorable outcome.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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