556 research outputs found

    Measurement of synchrotron-radiation-excited Kossel patterns

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    Kossel line patterns contain information on the crystalline structure, such as the magnitude and the phase of Bragg reflections. For technical reasons, most of these patterns are obtained using electron beam excitation, which leads to surface sensitivity that limits the spatial extent of the structural information. To obtain the atomic structure in bulk volumes, X-rays should be used as the excitation radiation. However, there are technical problems, such as the need for high resolution, low noise, large dynamic range, photon counting, twodimensional pixel detectors and the small spot size of the exciting beam, which have prevented the widespread use of Kossel pattern analysis. Here, an experimental setup is described, which can be used for the measurement of Kossel patterns in a reasonable time and with high resolution to recover structural information

    Phase field theory of polycrystalline solidification in three dimensions

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    A phase field theory of polycrystalline solidification is presented that is able to describe the nucleation and growth of anisotropic particles with different crystallographic orientation in three dimensions. As opposed with the two-dimensional case, where a single orientation field suffices, in three dimensions, minimum three fields are needed. The free energy of grain boundaries is assumed to be proportional to the angular difference between the adjacent crystals expressed here in terms of the differences of the four symmetric Euler parameters. The equations of motion for these fields are obtained from variational principles. Illustrative calculations are performed for polycrystalline solidification with dendritic, needle and spherulitic growth morphologies.Comment: 7 pages, 4 figures, submitted to Europhysics Letters on 14th February, 200

    Selective changes in inhibition as determinants for limited hyperexcitability in the insular cortex of epileptic rats

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    The insular cortex (IC) is involved in the generalization of epileptic discharges in temporal lobe epilepsy (TLE), while seizures originating in IC can mimic the epileptic phenotype seen in some TLE patients. Few studies have however addressed the changes occurring in the IC in TLE animal models. Here, we analyzed the immunohistochemical and electrophysiological properties of IC networks in non-epileptic control and pilocarpine-treated epileptic rats. Neurons identified with a neuron-specific nuclear protein antibody showed similar counts in the two types of tissue but parvalbumin- and neuropeptide Y-positive interneurons were significantly decreased (parvalbumin, approx. -35%; neuropeptide Y, approx. -38%; P<0.01) in the epileptic IC. Non-adapting neurons were more frequently seen in the epileptic IC during intracellular injection of depolarizing current pulses. In addition, single-shock electrical stimuli elicited network-driven epileptiform responses in 87% of epileptic and in 22% of non-epileptic control neurons (P<0.01) but spontaneous postsynaptic potentials had similar amplitude, duration and intervals of occurrence in the two groups. Finally, pharmacologically isolated, GABAA receptor-mediated inhibitory postsynaptic potentials had more negative reversal potential (P<0.01) and higher peak conductance (P<0.05) in epileptic tissue. These data reveal moderate increased network excitability in the IC of pilocarpine-treated epileptic rats. We propose that such limited degree of hyperexcitability originates from loss of parvalbumin- and neuropeptide Y-positive interneurons that is compensated by an increased drive for GABAA receptor-mediated inhibition

    Holographic Methods as Local Probes of the Atomic Order in Solids

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    In the last fifteen years several techniques based on the holographic principle have been developed for the study of the 3D local order in solids. These methods use various particles: electrons, hard x-ray photons, gamma photons, or neutrons to image the atoms. Although the practical realisation of the various imaging experiments is very different, there is a common thread; the use of inside reference points for holographic imaging. In this paper we outline the basics of atomic resolution holography using inside reference points, especially concentrating to the hard x-ray case. Further, we outline the experimental requirements and what has been practically realized in the last decade. At last we give examples of applications and future perspectives.Comment: 14 pages, 6 figure

    PROTECT: Relational Safety based Suicide Prevention Training Frameworks

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    Preventing suicide is a global priority and staff training is a core prevention strategy. However frontline pressures make translating training into better care and better outcomes difficult. The aim of the paper is to highlight challenges in suicide risk assessment and management and introduce training frameworks to assist with mindful practice so professionals can strike a balance between risk and recovery. We combined the scientific literature with contemporary practice from two successful initiatives from Cambridgeshire, UK; 333 – a recovery oriented model of inpatient/community crisis care and PROMISE – a programme to reduce coercion in care by enhancing patient experience. The resulting PROTECT (PROactive deTECTion) frameworks operationalise ongoing practice of relational safety in these programmes. PROTECT is a combination of novel concepts and adaptations of well-established therapeutic approaches. It has four training frameworks: AWARE for reflection on clinical decisions; DESPAIR for assessment; ASPIRE for management; NOTES for documentation. PROTECT aims to improve self-awareness of mental shortcuts, risk taking thresholds and increase rigour through time efficient crosschecks. The training frameworks should support a relational approach to self-harm/suicide risk detection, mitigation and documentation, making care safer and person-centred. The goal is to enthuse practitioners with recovery oriented practice that draws on the strengths of the person in distress and their natural circle of support. It will provide the confidence to engage in participatory approaches to seek out unique individualised solutions to the overwhelming psychological pain of suicidal distress. Future collaborative research with people with lived and carer experience is needed for fine-tuning

    Public health programmes to promote mental health in young people: a systematic integrative review protocol.

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    INTRODUCTION: In light of the ever-growing mental health disease burden among young people worldwide, we aim to systematically review the global literature to identify the public health programmes targeted at promoting mental health and well-being in young people, the reported/anticipated mental health-related outcomes of the implemented public health programmes and the reported facilitators and barriers in relation to the implementation of those public health programmes. METHODS AND ANALYSIS: A comprehensive literature search will be carried out in the following electronic bibliographic databases: MEDLINE, EMBASE, PsycINFO, Scopus, ASSIA, Web of Science, Global Health, AMED, Health Source and The Cochrane Library. Further, a manual search of the reference lists of eligible studies and reviews will be carried out. The search strategy will include combinations of three key blocks of terms, namely: 'young people', 'mental health' and 'public health programme', using database-specific subject headings and text words. Two reviewers will independently screen, assess data quality and extract data for synthesis. Disagreements at any stage will be resolved by consensus with the involvement of a third reviewer. Given the anticipated methodological pluralism of the potential eligible studies, we will provide a narrative synthesis of the findings on public health programmes aimed at promoting the mental health and well-being of young people according to identified thematic areas. Furthermore, a narrative synthesis of the reported facilitators and barriers in relation to the implementation of public health programmes will be provided. ETHICS AND DISSEMINATION: Given that the review findings will be focused on understanding the breadth and depth of the global research into public health programmes to promote mental health in young people with a particular emphasis on the facilitators and barriers of programmatic implementation, the findings will be of great value to inform future interventions, programmes and approaches to promote mental health and well-being of young people worldwide. PROSPERO REGISTRATION NUMBER: CRD42018099551

    Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

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    C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating the C60-C8H8 cocrystal with green or blue light a photochemical reaction was observed leading to a similar product to that of the thermal polymerization.Comment: 26 pages, 8 figures, to appear in Journal of Physical Chemistry B 2nd version: minor changes in wording, accepted version by journa

    Loneliness, coping, suicidal thoughts and self-harm during the COVID-19 pandemic: a repeat cross-sectional UK population survey

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    Objectives: There has been speculation on the impact of the COVID-19 pandemic and the associated lockdown on suicidal thoughts and self-harm and the factors associated with any change. We aimed to assess the effects and change in effects of risk factors including loneliness and coping, as well as pre-existing mental health conditions on suicidal thoughts and self-harm during the COVID-19 pandemic. Design: This study was a repeated cross-sectional online population-based survey. Participants and measures: Non-probability quota sampling was adopted on the UK adult population and four waves of data were analysed during the pandemic (17 March 2020 to 29 May 2020). Outcomes were suicidal thoughts and self-harm associated with the pandemic while loneliness, coping, pre-existing mental health conditions, employment status and demographics were covariates. We ran binomial regressions to evaluate the adjusted risks of the studied covariates as well as the changes in effects over time. Results: The proportion of individuals who felt lonely increased sharply from 9.8% to 23.9% after the UK lockdown began. Young people (aged 18–24 years), females, students, those who were unemployed and individuals with pre-existing mental health conditions were more likely to report feeling lonely and not coping well. 7.7%–10.0% and 1.9%–2.2% of respondents reported having suicidal thoughts and self-harm associated with the pandemic respectively throughout the period studied. Results from cross-tabulation and adjusted regression analyses showed young adults, coping poorly and with pre-existing mental health conditions were significantly associated with suicidal thoughts and self-harm. Loneliness was significantly associated with suicidal thoughts but not self-harm. Conclusions: The association between suicidality, loneliness and coping was evident in young people during the early stages of the pandemic. Developing effective interventions designed and coproduced to address loneliness and promote coping strategies during prolonged social isolation may promote mental health and help mitigate suicidal thoughts and self-harm associated with the pandemic
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