530 research outputs found

    Comparing attentional bias to smoking cues in current smokers, former smokers, and non-smokers using a dot-probe task

    Get PDF
    Much evidence documents that individuals with emotional and drug-use disorders demonstrate biased attention toward stimuli associated with their disorder. This bias appears to diminish following successful treatment. Two studies examined whether current cigarette smokers show biased attention toward smoking-related images compared with non-smokers (Studies 1 and 2) and whether this bias is less pronounced in former smokers (Study 2). Attentional bias toward cigarette-related photographs was examined using the dot-probe task. Pairs of images (one smoking-related) appeared side by side for 500 ms on a computer screen prior to the presentation of a probe (an asterisk) replacing one of the photographs. Subjects struck a key as quickly as possible to indicate the probe location. Attentional bias was defined as faster reaction times when the probe replaced the smoking-related image. In both studies, current smokers displayed significantly greater attentional bias toward cigarette stimuli than did non-smokers. Former smokers in Study 2 displayed an intermediate level of bias, but did not differ significantly in bias score from either of the other groups. These results support further use of the dot-probe task as a measure of attentional bias in non-abstinent smokers and in individuals undergoing smoking cessation treatment

    Nitrate triggered phosphoproteome changes and a PIN2 phosphosite modulating root system architecture

    Get PDF
    Nitrate commands genome-wide gene expression changes that impact metabolism, physiology, plant growth, and development. In an effort to identify new components involved in nitrate responses in plants, we analyze the Arabidopsis thaliana root phosphoproteome in response to nitrate treatments via liquid chromatography coupled to tandem mass spectrometry. 176 phosphoproteins show significant changes at 5 or 20 min after nitrate treatments. Proteins identified by 5 min include signaling components such as kinases or transcription factors. In contrast, by 20 min, proteins identified were associated with transporter activity or hormone metabolism functions, among others. The phosphorylation profile of NITRATE TRANSPORTER 1.1 (NRT1.1) mutant plants was significantly altered as compared to wild-type plants, confirming its key role in nitrate signaling pathways that involves phosphorylation changes. Integrative bioinformatics analysis highlights auxin transport as an important mechanism modulated by nitrate signaling at the post-translational level. We validated a new phosphorylation site in PIN2 and provide evidence that it functions in primary and lateral root growth responses to nitrate

    PG 2131+066: A Test of Pre-White Dwarf Asteroseismology

    Get PDF
    PG 2131+066 is a composite-spectrum binary with a hot pulsating PG 1159-type pre-white dwarf and an early M-type main sequence star. Analysis of Whole Earth Telescope observations of the pulsating pre-white dwarf component provided an asteroseismological determination of its mass, luminosity, and effective temperature. These determinations allowed Kawaler et al. (1995) to determine the distance to this star. In this paper, we refine the asteroseismological distance determination, and confirm the distance by an independent measurement to the system via the spectroscopic parallax of the M star. PG 2131+066 was observed by the HST using the original PC in September 1993. Exposures with filters F785LP and F555W both showed the companion at a distance of 0.3 arc seconds. Photometry of the images provides an apparent magnitude for the main sequence companion of v=18.97+/-0.15, from which we find a distance of 560 (+200 -134) pc. We also recalculated the asteroseismological distance to the pre-white dwarf using updated models and new spectroscopic constraints from UV spectra. The new seismological distance is 668 (+78 -83) pc, in satisfactory agreement with the distance of the secondary star. These results suggest that this is indeed a physical binary, and that seismological distance determination may be the best way to determine the distance to the pulsating hot pre-white dwarf stars.Comment: 13 pages, 4 figures, to appear in The Astrophysical Journal, Dec.10, 200

    Enhancing the FAIRness of Arctic Research Data Through Semantic Annotation

    Get PDF
    The National Science Foundation’s Arctic Data Center is the primary data repository for NSF-funded research conducted in the Arctic. There are major challenges in discovering and interpreting resources in a repository containing data as heterogeneous and interdisciplinary as those in the Arctic Data Center. This paper reports on advances in cyberinfrastructure at the Arctic Data Center that help address these issues by leveraging semantic technologies that enhance the repository’s adherence to the FAIR data principles and improve the Findability, Accessibility, Interoperability, and Reusability of digital resources in the repository. We describe the Arctic Data Center’s improvements. We use semantic annotation to bind metadata about Arctic data sets with concepts in web-accessible ontologies. The Arctic Data Center’s implementation of a semantic annotation mechanism is accompanied by the development of an extended search interface that increases the findability of data by allowing users to search for specific, broader, and narrower meanings of measurement descriptions, as well as through their potential synonyms. Based on research carried out by the DataONE project, we evaluated the potential impact of this approach, regarding the accessibility, interoperability, and reusability of measurement data. Arctic research often benefits from having additional data, typically from multiple, heterogeneous sources, that complement and extend the bases – spatially, temporally, or thematically – for understanding Arctic phenomena. These relevant data resources must be ‘found’, and ‘harmonized’ prior to integration and analysis. The findings of a case study indicated that the semantic annotation of measurement data enhances the capabilities of researchers to accomplish these tasks

    Engineered food supplement excipients from bitter cassava for minimisation of cassava processing waste in environment

    Get PDF
    This is a research paper unchecked large-scale rudimentary upstream (submerged and solid-state fermentation processes of bitter cassava roots into alcohol have often contributed significantly to agricultural wastes in the environment.Unchecked large-scale rudimentary upstream (sub-merged and solid state) fermentation processes of bitter cas- sava roots into alcohol have often contributed significantly to agricultural wastes into environment. Thus, the study explored a proven valorisation methodology, Simultaneous Release Recovery Cyanogenesis (SRRC) along with intact bitter cassava polysaccharide-rich derivatives (CWF), as an apt to find alternative materials for food supplement excipients. Triplicate CWF powder, peeled or intact bitter cassava roots, were produced and analysed to determine crit- ical properties suitable in tablet making. Exclusion approach, using SRRC and compaction, was performed to select desired powder properties for tablet formulation. Microcrystalline cellulose, with known properties for developing drug excipients, was used as a validation reference material. Tablets, for disintegration time and in- vitro dissolution rates studies were produced using wet-granulation, and their potential to release and bio-avail Iron-Zinc investigated in-vitro (pHs 1.2 and 6.8 solutions, 37 0 C). Morphology and Iron-Zinc dissolution-release mechanisms were examined. Kinetic models were used to describe matrix dissolution and Iron-Zinc release mech- anisms. Intact root powder compaction capacity, depicted by hardness, was 4.3, 4.4 and 4.6 KG at 200, 500 and 700 MPa respectively. Scanning Electron Microscopy (SEM) showed Iron-Zinc inclusion altered tablet morphol- ogy. Efficient matrix dissolution and Iron and Zinc release were achieved, showing apex recovery efficiency (98%, 30–45 min). Fitted models well-explained dissolution and release mechanisms (mean R 2 = 0.95), demonstrating adequacy. SRRC-improved intact bitter cassava was confirmed as potential alternative excipient’s matrix for Iron and Zinc release and bioavailability. Thus, this approach is practical for indirect waste elimination, and can promote strategy for sustainable valorisation of agricultural wastes and alternative functional food supplements delivery system

    Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges

    Get PDF
    One of the most challenging components of the UK nuclear legacy is Magnox sludge, arising from the corrosion of Mg alloy-clad irradiated metallic U fuel that has been stored in high pH ponds. The sludges mainly comprise Mg hydroxide and carbonate phases, contaminated with fission products and actinides, including Pu. Cementation and deep geological disposal is one option for the long-term management of this material, but there is a need to understand how Pu may be leached from the waste, if it is exposed to groundwater. Here, we show that cemented Mg(OH)2 powder prepared with Pu(IV)aq is altered on contact with water to produce a visibly altered ‘leached zone’, which penetrates several hundred microns into the sample. In turn, this zone shows slow leaching of Pu, with long-term leaching rates between 1.8–4.4 × 10−5% of total Pu per day. Synchrotron micro-focus X-ray fluorescence mapping identified decreased Pu concentration within the ‘leached zone’. A comparison of micro-focus X-ray absorption spectroscopy (µ-XAS) spectra collected across both leached and unleached samples showed little variation, and indicated that Pu was present in a similar oxidation state and coordination environment. Fitting of the XANES spectra between single oxidation state standards and EXAFS modeling showed that Pu was present as a mixture of Pu(IV) and Pu(V). The change in Pu oxidation from the stock solution suggests that partial Pu oxidation occurred during sample ageing. Similarity in the XAS spectra from all samples, with different local chemistries, indicated that the Pu oxidation state was not perturbed by macro-scale variations in cement chemistry, surface oxidation, sample aging, or the leaching treatment. These experiments have demonstrated the potential for leaching of Pu from cementitious waste forms, and its underlying significance requires further investigation

    Plutonium Migration during the Leaching of Cemented Radioactive Waste Sludges

    Get PDF
    One of the most challenging components of the UK nuclear legacy is Magnox sludge, arising from the corrosion of Mg alloy-clad irradiated metallic U fuel that has been stored in high pH ponds. The sludges mainly comprise Mg hydroxide and carbonate phases, contaminated with fission products and actinides, including Pu. Cementation and deep geological disposal is one option for the long-term management of this material, but there is a need to understand how Pu may be leached from the waste, if it is exposed to groundwater. Here, we show that cemented Mg(OH)2 powder prepared with Pu(IV)aq is altered on contact with water to produce a visibly altered ‘leached zone’, which penetrates several hundred microns into the sample. In turn, this zone shows slow leaching of Pu, with long-term leaching rates between 1.8–4.4 × 10−5% of total Pu per day. Synchrotron micro-focus X-ray fluorescence mapping identified decreased Pu concentration within the ‘leached zone’. A comparison of micro-focus X-ray absorption spectroscopy (µ-XAS) spectra collected across both leached and unleached samples showed little variation, and indicated that Pu was present in a similar oxidation state and coordination environment. Fitting of the XANES spectra between single oxidation state standards and EXAFS modeling showed that Pu was present as a mixture of Pu(IV) and Pu(V). The change in Pu oxidation from the stock solution suggests that partial Pu oxidation occurred during sample ageing. Similarity in the XAS spectra from all samples, with different local chemistries, indicated that the Pu oxidation state was not perturbed by macro-scale variations in cement chemistry, surface oxidation, sample aging, or the leaching treatment. These experiments have demonstrated the potential for leaching of Pu from cementitious waste forms, and its underlying significance requires further investigation
    corecore