95 research outputs found
Molecular Conductors from Neutral-Radical Charge-Transfer Salts:Preparation and Characterization of an Iodine-Doped Hexagonal Phase of 1,2,3,5-Dithiadiazolyl ([HCN2S2]∙)
Sublimation of 1,2,3,5-dithiadiazolyl in vacuo affords a triclinic phase of the dimer [HCN2S2]2. The crystals belong to the space group P¯1, a = 6.816(3), b = 13.940(2), c = 14.403(3) Å, α = 116.830(14), β = 98.64(3), γ = 99.18(3)°, FW = 212.4 (for [HCN2S2]2·[N2]0.08) Z = 6. The crystal structure consists of stacked dimers, with three dimers per asymmetric unit. Pairs of asymmetric units, related by an inversion center, generate a pinwheel motif consisting of six dimers. The columnar structure associated with these pinwheels forms close-packed sets of “molecular tubes”. Cosublimation of the radical in the presence of iodine in the mole ratio (HCN2S2:I = 5:1) yields an iodine-doped hexagonal phase of composition [HCN2S2]6[I]1.1. Crystals of this material belong to the space group P61, a = b = 14.132(16), c = 3.352(5) Å, FW = 128.20, Z = 6. The crystal structure consists of sixfold pinwheels in which the now evenly spaced HCN2S2 rings form a spiral about the 61 axis. The iodine atoms lie within the columnar cavity of the pinwheels in a disordered array wrapped tightly about the sixfold screw axis. The single-crystal conductivity of the doped material is 15 S cm-1 at room temperature. Raman spectroscopic and magnetic susceptibility measurements on the doped material are reported
Diving into the vertical dimension of elasmobranch movement ecology
Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements
Novel genetic loci associated with hippocampal volume
The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness
Measuring progress and projecting attainment on the basis of past trends of the health-related Sustainable Development Goals in 188 countries: an analysis from the Global Burden of Disease Study 2016
The UN’s Sustainable Development Goals (SDGs) are grounded in the global ambition of “leaving no one behind”. Understanding today’s gains and gaps for the health-related SDGs is essential for decision makers as they aim to improve the health of populations. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016), we measured 37 of the 50 health-related SDG indicators over the period 1990–2016 for 188 countries, and then on the basis of these past trends, we projected indicators to 2030
Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016
As mortality rates decline, life expectancy increases, and populations age, non-fatal outcomes of diseases and injuries are becoming a larger component of the global burden of disease. The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of prevalence, incidence, and years lived with disability (YLDs) for 328 causes in 195 countries and territories from 1990 to 2016
Erratum: Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017
Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning
Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign
High Energy AstrophysicsInstrumentatio
Recommended from our members
Radiation testing of organic ion exchange resins
A number of ion exchange materials are being evaluated as part of the Tank Waste Remediation System (TWRS) Pacific Northwest Laboratory (PNL) Pretreatment Project for the removal of {sup 137}Cs from aqueous tank wastes. Two of these materials are organic resins; a phenol-formaldehyde resin (Duolite CS-100) produced by Rohm and Haas Co. (Philadelphia, Pennsylvania) and a resorcinol-formaldehyde (RF) resin produced by Boulder Scientific Co. (Mead, Colorado). One of the key parameters in the assessment of the organic based ion exchange materials is its useful lifetime in the radioactive and chemical environment that will be encountered during waste processing. The focus of the work presented in this report is the radiation stability of the CS-100 and the RF resins. The scope of the testing included one test with a sample of the CS-100 resin and testing of two batches of the RF resin (BSC-187 and BSC-210). Samples of the exchangers were irradiated with a {sup 60}Co source to a total absorbed dose of 10{sup 9} R over a period of 5 months in a static (no flow) and a flowing configuration with neutralized current acid waste (NCAW) simulant as a feed. Based on a maximum concentration of {sup 137}Cs on the resin that would result from processing NCAW, this dose represents an operational period of at least 150 days for the RF resin and at least 1260 days for the CS-100 resin. Gas generation in the static experiment was continuously monitored and G values (molecules of gas per 100 eV) were determined for each species. Resin samples were obtained periodically and the equilibrium behavior of the resins was assessed by determining the distribution coefficients (K{sub d}s). Structural information was also obtained by {sup 13}C cross polarization magic angle (CPMAS) nuclear magnetic resonance (NMR) spectrometry and Fourier Transform Infrared (FTIR) spectroscopy so that changes to the chemical structure could be correlated with changes in K{sub d}
Recommended from our members
Supernatant treatment technology development: Report for the second quarter FY 1994
This report describes the experimental work conducted at the Pacific Northwest Laboratory during the Second Quarter FY 1994 under the Supernatant Treatment Technology Development Task of the Tank Waste Remediation System (TWRS) Pretreatment Technology Development Project. The project goal is to remove enough cesium-137 from the tank waste so that the resulting low-level waste form will meet Nuclear Regulatory Commission requirements. Experiments were performed in the areas of batch equilibrium studies of ion exchangers, ion exchanger loading, ion exchanger elution, and radiation and chemical stability of selected ion exchangers. Column loading experiment results showed that cesium removal efficiency was lower than predicted. Elution experiments showed that BSC-210 material for cesium removal was superior to another material tested. Radiation and chemical stability studies were continued on Resorcinol-Formaldehyde resins. 10 refs., 11 figs., 3 tabs
- …