289 research outputs found

    Physical and dynamical characterisation of low Delta-V NEA (190491) 2000 FJ10

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    We investigated the physical properties and dynamical evolution of Near Earth Asteroid (NEA) (190491) 2000 FJ10 in order to assess the suitability of this accessible NEA as a space mission target. Photometry and colour determination were carried out with the 1.54 m Kuiper Telescope and the 10 m Southern African Large Telescope during the object's recent favourable apparition in 2011-12. During the earlier 2008 apparition, a spectrum of the object in the 6000-9000 Angstrom region was obtained with the 4.2 m William Herschel Telescope. Interpretation of the observational results was aided by numerical simulations of 1000 dynamical clones of 2000 FJ10 up to 10^6 yr in the past and in the future. The asteroid's spectrum and colours determined by our observations suggest a taxonomic classification within the S-complex although other classifications (V, D, E, M, P) cannot be ruled out. On this evidence, it is unlikely to be a primitive, relatively unaltered remnant from the early history of the solar system and thus a low priority target for robotic sample return. Our photometry placed a lower bound of 2 hrs to the asteroid's rotation period. Its absolute magnitude was estimated to be 21.54+-0.1 which, for a typical S-complex albedo, translates into a diameter of 130+-20 m. Our dynamical simulations show that it has likely been an Amor for the past 10^5 yr. Although currently not Earth-crossing, it will likely become so during the period 50 - 100 kyr in the future. It may have arrived from the inner or central Main Belt > 1 Myr ago as a former member of a low-inclination S-class asteroid family. Its relatively slow rotation and large size make it a suitable destination for a human mission. We show that ballistic Earth-190491-Earth transfer trajectories with Delta-V < 2 km s^-1 at the asteroid exist between 2052 and 2061.Comment: 2 Tables, 11 Figures, accepted for publication in Astronomy & Astrophysic

    Spatial distribution of micrometre‐scale porosity and permeability across the damage zone of a reverse‐reactivated normal fault in a tight sandstone : Insights from the Otway Basin, SE Australia

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    This research forms part of a PhD project supported by the Australian Research Council [Discovery Project DP160101158] and through an Australian Government Research Training Program Scholarship. Dave Healy acknowledges the support of the Natural Environment Research Council (NERC, UK) through the award NE/N003063/1 ‘Quantifying the Anisotropy of Permeability in Stressed Rock’. This study was also funded by scholarships from the Petroleum Exploration Society of Australia and the Australian Petroleum Production and Exploration Association. We thank Gordon Holm for preparing thin sections and Colin Taylor for carrying out particle size measurements and mercury injection capillary pressure analyses. Aoife McFadden and David Kelsey from Adelaide Microscopy, Braden Morgan, and Sophie Harland are acknowledged for their assistance with laboratory work. Field assistants James Hall, Rowan Hansberry, and Lachlan Furness are also gratefully acknowledged for their assistance with sample collection. Discussions with Ian Duddy on the mineralogy of the Eumeralla Formation are also greatly appreciated. This forms TRaX record 416.Peer reviewedPublisher PD

    Evaluation of expression and function of the H+/myo-inositol transporter HMIT;

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    BACKGROUND: The phosphoinositide (PIns) signalling pathway regulates a series of neuronal processes, such as neurotransmitter release, that are thought to be altered in mood disorders. Furthermore, mood-stabilising drugs have been shown to inhibit key enzymes that regulate PIns production and alter neuronal growth cone morphology in an inositol-reversible manner. Here, we describe analyses of expression and function of the recently identified H+/myo-inositol transporter (HMIT) investigated as a potential regulator of PIns signalling. RESULTS: We show that HMIT is primarily a neuronal transporter widely expressed in the rat and human brain, with particularly high levels in the hippocampus and cortex, as shown by immunohistochemistry. The transporter is localised at the Golgi apparatus in primary cultured neurones. No HMIT-mediated electrophysiological responses were detected in rat brain neurones or slices; in addition, inositol transport and homeostasis were unaffected in HMIT targeted null-mutant mice. CONCLUSION: Together, these data do not support a role for HMIT as a neuronal plasma membrane inositol transporter, as previously proposed. However, we observed that HMIT can transport inositol triphosphate, indicating unanticipated intracellular functions for this transporter that may be relevant to mood control

    RIPK3-mediated cell death is involved in DUX4-mediated toxicity in facioscapulohumeral dystrophy

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    BACKGROUND: Facioscapulohumeral dystrophy (FSHD) is caused by mutations leading to the aberrant expression of the DUX4 transcription factor in muscles. DUX4 was proposed to induce cell death, but the involvement of different death pathways is still discussed. A possible pro-apoptotic role of DUX4 was proposed, but as FSHD muscles are characterized by necrosis and inflammatory infiltrates, non-apoptotic pathways may be also involved. METHODS: We explored DUX4-mediated cell death by focusing on the role of one regulated necrosis pathway called necroptosis, which is regulated by RIPK3. We investigated the effect of necroptosis on cell death in vitro and in vivo experiments using RIPK3 inhibitors and a RIPK3-deficient transgenic mouse model. RESULTS: We showed in vitro that DUX4 expression causes a caspase-independent and RIPK3-mediated cell death in both myoblasts and myotubes. In vivo, RIPK3-deficient animals present improved body and muscle weights, a reduction of the aberrant activation of the DUX4 network genes, and an improvement of muscle histology. CONCLUSIONS: These results provide evidence for a role of RIPK3 in DUX4-mediated cell death and open new avenues of research

    The role of trust and hope in antipsychotic medication reviews between GPs and service users a realist review

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    Abstract Background Increasing number of service users diagnosed with schizophrenia and psychosis are being discharged from specialist secondary care services to primary care, many of whom are prescribed long-term antipsychotics. It is unclear if General Practitioners (GPs) have the confidence and experience to appropriately review and adjust doses of antipsychotic medication without secondary care support. Aim To explore barriers and facilitators of conducting antipsychotic medication reviews in primary care for individuals with no specialist mental health input. Design &amp; setting Realist review in general practice settings. Method A realist review has been conducted to synthesise evidence on antipsychotic medication reviews conducted in primary care with service users diagnosed with schizophrenia or psychosis. Following initial scoping searches and discussions with stakeholders, a systematic search and iterative secondary searches were conducted. Articles were systematically screened and analysed to develop a realist programme theory explaining the contexts (C) and mechanisms (M) which facilitate or prevent antipsychotic medication reviews (O) in primary care settings, and the potential outcomes of medication reviews. Results Meaningful Antipsychotic medication reviews may not occur for individuals with only primary care medical input. Several, often mutually reinforcing, mechanisms have been identified as potential barriers to conducting such reviews, including low expectations of recovery for people with severe mental illness, a perceived lack of capability to understand and participate in medication reviews, linked with a lack of information shared in appointments between GPs and Service Users, perceived risk and uncertainty regarding antipsychotic medication and illness trajectory. Conclusions The review identified reciprocal and reinforcing stereotypes affecting both GPs and service users. Possible mechanisms to counteract these barriers are discussed, including realistic expectations of medication, and the need for increased information sharing and trust between GPs and service users. </jats:sec

    A thermophysical analysis of the (1862) Apollo Yarkovsky and YORP effects

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    Context. The Yarkovsky effect, which causes orbital drift, and the YORP effect, which causes changes in rotation rate and pole orientation, play important roles in the dynamical and physical evolution of asteroids. Near-Earth asteroid (1862) Apollo has strong detections of both orbital semimajor axis drift and rotational acceleration. Aims. To produce a unified model that can accurately match both observed effects using a single set of thermophysical properties derived from ground-based observations, and to determine Apollo’s long term evolution. Methods. We use light-curve shape inversion techniques and the Advanced Thermophysical Model (ATPM) on published light-curve, thermal-infrared, and radar observations to constrain Apollo’s thermophysical properties. The derived properties are used to make detailed predictions of Apollo’s Yarkovsky and YORP effects, which are then compared with published measurements of orbital drift and rotational acceleration. The ATPM explicitly incorporates 1D heat conduction, shadowing, multiple scattering of sunlight, global self-heating, and rough surface thermal-infrared beaming in the model predictions. Results. We find that ATPM can accurately reproduce the light-curve, thermal-infrared, and radar observations of Apollo, and simultaneously match the observed orbital drift and rotational acceleration using: a shape model with axis ratios of 1.94:1.65:1.00, an effective diameter of 1.55 ± 0.07 km, a geometric albedo of 0.20 ± 0.02, a thermal inertia of 140 +140-100 J m-2 K-1 s-1/2, a highly rough surface, and a bulk density of 2850 +480-680 kg m-3. Using these properties we predict that Apollo’s obliquity is increasing towards the 180 degree YORP asymptotic state at a rate of 1.5 +0.3-0.5 degrees per 105 yr. Conclusions. The derived thermal inertia suggests that Apollo has loose regolith material resting on its surface, which is consistent with Apollo undergoing a recent resurfacing event based on its observed Q-type spectrum. The inferred bulk density is consistent with those determined for other S-type asteroids, and suggests that Apollo has a fractured interior. The YORP effect is acting on a much faster timescale than the Yarkovsky effect and will dominate Apollo’s long term evolution. The ATPM can readily be applied to other asteroids with similar observational data sets

    The value of rapid functional assays of germline p53 status in LFS and LFL families

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    We have tested two rapid assays of p53 function, namely the apoptotic assay and the FASAY as means of detecting germline p53 mutations in members of Li–Fraumeni and Li–Fraumeni-like families. Results of the functional assays have been compared with direct sequencing of all 11 exons of the p53 gene. The results show good agreement between the two functional assays and between them and sequencing. No false-positives or negatives were seen with either functional assay although the apoptotic assay gave one borderline result for an individual without a mutation. As an initial screen the apoptotic assay is not only rapid but inexpensive and very simple to perform. It would be expected to detect any germline defect that leads to loss of p53 function. The apoptotic assay could be ideal as a means of prescreening large numbers of samples and identifying those that require further investigation. The FASAY detects mutations in exons 4–10, is rapid and distinguishes between functionally important and silent mutations. © 2000 Cancer Research Campaig
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