The National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion programs. We report on the ...preliminary design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community's understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beamsplitter and gratings before the shot. A deep-UV probe beam (λ0 between 185-215 nm) will optimally collect Thomson scattered light from plasma densities of 5 x 1020 electrons cm3 while a 3ω probe will optimally collect Thomson scattered light from plasma densities of 1 x 1019 electrons cm3. We report the phase I design of a two phase design strategy. Phase I includes the OTS recording system to measure background levels at NIF and phase II will include the integration of a probe laser.
Prospective life cycle assessment (LCA) provides information on the environmental consequences of individual actions. Retrospective LCA provides information about the environmental properties of the ...life cycle investigated and of its subsystems. In this paper we analyse the links between the choice of methodology and different theories of normative moral philosophy. The choice of electricity data in an LCA of a conference site with local hydropower production is discussed as an illustration. The two types of LCA can be related to different theories on the characteristics of a good action. Each type of LCA, as well as each of the moral theories, can be criticised from the alternative point of departure. Decisions based on retrospective LCA can have environmentally undesirable consequences. On the other hand, prospective LCA can appear unfair and result in environmentally sub-optimised systems. Both types of LCA also have methodological limitations. We cannot conclude that one type is superior to the other, but the choice of methodology should be consistent with the information sought in the LCA.
This paper presents a study where sustainable development indicators (SDIs) for sludge handling and wastewater treatment systems were constructed in co-operation with a large Swedish water company. ...Results from a life cycle assessment, a risk assessment, an economic assessment and an uncertainty assessment were used as inputs for ranking technical options of sludge handling by use of multi-criteria analysis (MCA). The MCA included assessment of the different technical options, valuation of different, and often conflicting, aspects of sustainability and weighting of various criteria. On basis of the preferences expressed in the MCA, a number of SDIs and, when possible, targets for sustainable development, were formulated. The resulting SDIs reflected economic, environmental, technical and social aspects of sustainable development of sludge handling systems. Where possible, the coverage of the indicators was extended to the entire wastewater system.
While neurodevelopmental disorders (NDDs) are highly heritable, several environmental risk factors have also been suggested. However, the role of familial confounding is unclear. To shed more light ...on this, we reviewed the evidence from twin and sibling studies. A systematic review was performed on case control and cohort studies including a twin or sibling within-pair comparison of neurodevelopmental outcomes, with environmental exposures until the sixth birthday. From 7,315 screened abstracts, 140 eligible articles were identified. After adjustment for familial confounding advanced paternal age, low birth weight, birth defects, and perinatal hypoxia and respiratory stress were associated with autism spectrum disorder (ASD), and low birth weight, gestational age and family income were associated with attention-deficit/hyperactivity disorder (ADHD), categorically and dimensionally. Several previously suspected factors, including pregnancy-related factors, were deemed due to familial confounding. Most studies were conducted in North America and Scandinavia, pointing to a global research bias. Moreover, most studies focused on ASD and ADHD. This genetically informed review showed evidence for a range of environmental factors of potential casual significance in NDDs, but also points to a critical need of more genetically informed studies of good quality in the quest of the environmental causes of NDDs.
In chemical risk assessment, measured or modelled environmental concentrations are compared to environmental exposure limits (EELs), such as Predicted No Effect Concentrations (PNECs) or hazardous ...concentrations for 5% of species (HC05s) derived from species sensitivity distributions (SSDs). However, for many chemicals the EELs include large uncertainties or, in the worst case, the necessary data for their estimation are completely missing. This makes the assessment of chemical risks and any subsequent implementation of management strategies challenging. In this study we analyzed the uncertainty of EELs and its impact on chemical risk assessment. First, we compared three individual EEL datasets, two primarily based on experimental data and one based on computational predictions. The comparison demonstrates large disagreements between EEL data sources, with experimentally derived EELs differing by more than seven orders of magnitude. In a case-study, based on the predicted emissions of 2005 chemicals, we showed that these uncertainties lead to significantly different risk assessment outcomes, including large differences in the magnitude of the total risk, risk driver identification, and the ranking of use categories as risk contributors. We also show that the large data-gaps in EEL datasets cannot be covered by commonly used computational approaches (QSARs). We conclude that an expanded framework for interpreting risk characterization outcomes is needed. We also argue that the large data-gaps present in ecotoxicological data need to be addressed in order to achieve the European zero pollution vision as the growing emphasis on ambient exposures will further increase the demand for accurate and well-established EELs.
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•Environmental exposure limits (EEL) from different sources show large discrepancies.•Computational predictions of EEL are biased and overestimate toxicity and risks.•Complex chemical mixtures cannot be adequately assessed for risk due to missing data.•Risk drivers are highly dependent on the choice of EEL, hampering management.•Increased quality and quantity of EELs is vital for improving mixture risk assessment.
Come together, right now: Acyltrifluoroborates and O‐benzoyl hydroxylamines come together to form amides in water (see scheme). The ligations are complete within minutes at room temperature and do ...not require any reagents or catalysts. The reaction has a broad substrate scope and tolerates unprotected functional groups.
The compatibility of photochemistry with solid-phase peptide synthesis is demonstrated via photochemical hydroalkylation to form C(sp3)–C(sp3) bonds between on-resin Giese acceptors and ...redox-active esters. Both iridium-based photocatalysts and Hantszch ester led to high yields, with final reaction conditions producing full conversions within 30 min under ambient conditions. The chemistry is compatible with a broad range of peptide side chains, redox-active esters, and resin. These conditions represent the first example of photochemical peptide modifications on resin.
Chemical emissions from households originate from a wide range of sources and results in highly diverse mixtures. This makes traditional monitoring based on analytical chemistry challenging, ...especially for compounds that appear in low concentrations. We therefore developed a method for predicting emissions of chemicals from households into wastewater, relying on consumption patterns from multiple data sources. The method was then used to predict the emissions of chemical preparations, chemicals leaching from textiles and prescription pharmaceuticals in Sweden. In total we predicted emissions of 2007 chemicals with a combined emission of 62,659 tonnes per year – or 18 g/person and day. Of the emitted chemicals, 2.0% (w/w) were either classified as hazardous to the environment or were both persistent and mobile. We also show that chemical emissions come from a wide range of uses and that the total emission of any individual chemical is determined primarily by its use pattern, not by the total amount used. This emphasizes the need for continuous updates and additional knowledge generation both on emission factors and excretion rates as well as a need for improved reporting on the intended use of individual chemicals. Finally, we scrutinize the model and its uncertainty and suggest areas that need improvement to increase the accuracy of future emission modelling. We conclude that emission modelling can help guide environmental monitoring and provide input into management strategies aimed at reducing the environmental effect caused by hazardous chemicals.
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•Emission were estimated for 2007 unique chemicals.•From Swedish consumers the total emission was estimated to be 62,659 tonnes per year.•The estimates suggest emissions of approximately 18 g of chemicals per person and day.•96% (by weight) of emissions are estimated to originate from chemical preparations.•2% (w/w) are hazardous to the environment or human health, or persistent and mobile.
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