1,977 research outputs found

    Studying the spatial distribution of interstellar dust

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    The spacial distribution of interstellar dust reflects both interstellar dynamics and the processes which form and destroy dust in the interstellar medium (ISM). The IRAS survey, because of its high sensitivity to thermal emission from dust in the IR, provides new approaches to determining the spatial distribution of dust. The initial results are reported of an attempt to use the IRAS data to probe the spatial distribution of dust - by searching for thermal emission from dust in the vicinity of bright stars. These results show that this technique (which relies on finding IR emission associated with randomly selected stars) can ultimately be used to study the distribution of dust in the ISM. The density of the cloud producing the IR emission may be derived by assuming that the dust is at its projected distance from the star and that the heating is due to the star's (known) radiation field. The heating radiation is folded into a grain model, and the number of emitting grains adjusted to reproduce the observed energy distribution. It is noted that this technique is capable in principle of detecting dust densities much lower than those typical of the cirrus clouds

    On the role of intrinsic disorder in the structural phase transition of magnetoelectric EuTiO3

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    Up to now the crystallographic structure of the magnetoelectric perovskite EuTiO3 was considered to remain cubic down to low temperature. Here we present high resolution synchrotron X-ray powder diffraction data showing the existence of a structural phase transition, from cubic Pm-3m to tetragonal I4/mcm, involving TiO6 octahedra tilting, in analogy to the case of SrTiO3. The temperature evolution of the tilting angle indicates a second-order phase transition with an estimated Tc=235K. This critical temperature is well below the recent anomaly reported by specific heat measurement at TA\sim282K. By performing atomic pair distribution function analysis on diffraction data we provide evidence of a mismatch between the local (short-range) and the average crystallographic structures in this material. Below the estimated Tc, the average model symmetry is fully compatible with the local environment distortion but the former is characterized by a reduced value of the tilting angle compared to the latter. At T=240K data show the presence of local octahedra tilting identical to the low temperature one, while the average crystallographic structure remains cubic. On this basis, we propose intrinsic lattice disorder to be of fundamental importance in the understanding of EuTiO3 properties.Comment: 13 pages, 8 figures, 2 table

    Co-located Heroin Assisted Treatment within primary care: A preliminary analysis of the implications for healthcare access, cost, and treatment delivery in the UK.

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    The UK is experiencing its highest rate of drug related deaths in 25 years. Poor and inconsistent access to healthcare negatively impacts health outcomes for people who use drugs. Innovation in models of care which promote access and availability of physical treatment is fundamental. Heroin Assisted Treatment (HAT) is a treatment modality targeted at the most marginalised people who use drugs, at high risk of mortality and morbidity. The first service-provider initiated HAT service in the UK ran between October 2019 and November 2022 in Middlesbrough, England. The service was co-located within a specialist primary care facility offering acute healthcare treatment alongside injectable diamorphine. Analysis of anonymised health records for healthcare costs (not including drug treatment) took place using descriptive statistics prior and during engagement with HAT, at both three (n=15) and six (n=12) months. Primary outcome measures were incidents of wound care, skin and soft tissue infections (SSTIs), overdose (OD) events, unplanned overnight stays in hospital, treatment engagement (general and within hospital care settings) and ambulance incidents. Secondary outcome measures were costs associated with these events. A shift in healthcare access for participants during HAT engagement was observed. HAT service attendance appeared to support health promoting preventative care, and reduce reactive reliance on emergency healthcare systems. At three and six months, engagement for preventative wound care and treatment for SSTIs increased at the practice. Unplanned emergency healthcare interactions for ODs, overnight hospital stays, serious SSTIs, and ambulance incidents reduced, and there was an increase in treatment engagement (i.e. a reduction in appointments which were not engaged with). There was a decrease in treatment engagement in hospital settings. Changes in healthcare utilisation during HAT translated to a reduction in healthcare costs of 58% within six months compared to the same timeframe from the period directly prior to commencing HAT. This exploratory study highlights the potential for innovative harm reduction interventions such as HAT, co-located with primary care services, to improve healthcare access and engagement for a high-risk population. Increased uptake of primary healthcare services translated to reductions in emergency healthcare use and associated costs. Although costs of HAT provision are substantial, the notable cost-savings in health care should be an important consideration in service implementation planning. [Abstract copyright: Copyright © 2024. Published by Elsevier B.V.

    Safety of inadvertent administration of live zoster vaccine to immunosuppressed individuals in a UK-based observational cohort analysis.

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    OBJECTIVES: To investigate the safety of live attenuated varicella zoster vaccination when administered to immunosuppressed individuals. DESIGN: Prospective observational cohort study. SETTING: The study used anonymised data from the Clinical Practice Research Datalink (CPRD), comprising a representative sample of routinely collected primary care data in England between 2013 and 2017 and and linked Hospital Episode Statistics data. PARTICIPANTS: 168 767 individuals age-eligible for varicella zoster vaccination registered at a general practice in England contributing data to CPRD. MAIN OUTCOME MEASURES: Electronic health records indicating immunosuppression, zoster vaccination, diagnoses of specific varicella-zoster virus (VZV)-related disease and non-specific rash/encephalitis compatible with VZV-related disease. RESULTS: Between 1 September 2013 and 31 August 2017, a period of immunosuppression was identified for 9093/168 767 (5.4%; 95% CI: 5.3%-5.5%) individuals age-eligible for zoster vaccination. The overall rate of vaccination while immunosuppressed was 1742/5251 (33.2 per 100 adjusted person years at risk; 95% CI: 31.9%-34.5%). Follow-up of the 1742 individuals who were inadvertently vaccinated while immunosuppressed identified only two cases of VZV-related disease within 8 weeks of vaccination (0.1%; 95% CI: 0.01%-0.4%), both primary care diagnoses of 'shingles', neither with a related hospital admission. CONCLUSIONS: Despite evidence of inadvertent vaccination of immunosuppressed individuals with live zoster vaccination, there is a lack of evidence of severe consequences including hospitalisation. This should reassure primary care staff and encourage vaccination of mildly immunosuppressed individuals who do not meet current thresholds for contraindication. These findings support a review of the extent to which live zoster vaccination is contraindicated among the immunosuppressed

    Relationship between the Montreal Cognitive Assessment and Mini-mental State Examination for assessment of mild cognitive impairment in older adults

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    BACKGROUND: The Montreal Cognitive Assessment (MoCA) was developed to enable earlier detection of mild cognitive impairment (MCI) relative to familiar multi-domain tests like the Mini-Mental State Exam (MMSE). Clinicians need to better understand the relationship between MoCA and MMSE scores. METHODS: For this cross-sectional study, we analyzed 219 healthy control (HC), 299 MCI, and 100 Alzheimer's disease (AD) dementia cases from the Alzheimer's Disease Neuroimaging Initiative (ADNI)-GO/2 database to evaluate MMSE and MoCA score distributions and select MoCA values to capture early and late MCI cases. Stepwise variable selection in logistic regression evaluated relative value of four test domains for separating MCI from HC. Functional Activities Questionnaire (FAQ) was evaluated as a strategy to separate dementia from MCI. Equi-percentile equating produced a translation grid for MoCA against MMSE scores. Receiver Operating Characteristic (ROC) analyses evaluated lower cutoff scores for capturing the most MCI cases. RESULTS: Most dementia cases scored abnormally, while MCI and HC score distributions overlapped on each test. Most MCI cases scored ≥ 17 on MoCA (96.3%) and ≥ 24 on MMSE (98.3%). The ceiling effect (28-30 points) for MCI and HC was less using MoCA (18.1%) versus MMSE (71.4%). MoCA and MMSE scores correlated most for dementia (r = 0.86; versus MCI r = 0.60; HC r = 0.43). Equi-percentile equating showed a MoCA score of 18 was equivalent to MMSE of 24. ROC analysis found MoCA ≥ 17 as the cutoff between MCI and dementia that emphasized high sensitivity (92.3%) to capture MCI cases. The core and orientation domains in both tests best distinguished HC from MCI groups, whereas comprehension/executive function and attention/calculation were not helpful. Mean FAQ scores were significantly higher and a greater proportion had abnormal FAQ scores in dementia than MCI and HC. CONCLUSIONS: MoCA and MMSE were more similar for dementia cases, but MoCA distributes MCI cases across a broader score range with less ceiling effect. A cutoff of ≥ 17 on the MoCA may help capture early and late MCI cases; depending on the level of sensitivity desired, ≥ 18 or 19 could be used. Functional assessment can help exclude dementia cases. MoCA scores are translatable to the MMSE to facilitate comparison

    Dynamics in the ordered and disordered phases of barocaloric adamantane

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    High-entropy order-disorder phase transitions can be used for efficient and eco-friendly barocaloric solid-state cooling. Here the barocaloric effect is reported in an archetypal plastic crystal, adamantane. Adamantane has a colossal isothermally reversible entropy change of 106 J K-1 kg-1 . Extremely low hysteresis means that this can be accessed at pressure differences less than 200 bar. Configurational entropy can only account for about 40% of the total entropy change; the remainder is due to vibrational effects. Using neutron spectroscopy and supercell lattice dynamics calculations, it is found that this vibrational entropy change is mainly caused by softening in the high-entropy phase of acoustic modes that correspond to molecular rotations. We attribute this behaviour to the contrast between an 'interlocked' state in the low-entropy phase and sphere-like behaviour in the high-entropy phase. Although adamantane is a simple van der Waals solid with near-spherical molecules, this approach can be leveraged for the design of more complex barocaloric molecular crystals. Moreover, this study shows that supercell lattice dynamics calculations can accurately map the effect of orientational disorder on the phonon spectrum, paving the way for studying the vibrational entropy, thermal conductivity, and other thermodynamic effects in more complex materials.Comment: 14 pages, 6 figure

    Recommendations for assessing cognitive risks in young children treated for ependymoma for clinical and research protocols: evidence from a systematic literature review

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    Background: Current treatment approaches for pediatric ependymoma differ between North American and European studies. Post-surgical adjuvant irradiation is used in children aged <36 months in North America, whilst European approaches use chemotherapy to avoid or defer radiotherapy until three years of age, in order to avoid late neurocognitive toxicity. To establish evidence for the effects of cranial radiotherapy in children aged <36 months with ependymoma on neurocognitive outcomes, we conducted a systematic literature review assessing methodological approaches for measuring neurocognitive outcome. Methods: Eight databases were selected to perform an advanced search, retrieval and systematic review of papers describing neurocognitive outcome in children diagnosed with ependymoma who received cranial radiotherapy at <36 months. Results: Limitations of published data permitted descriptive analysis only. Considerable variation in reporting survival rates, techniques and timing of psychometric testing and the results of neurocognitive outcomes was identified. Conclusions: The review identified significant inconsistencies of neurocognitive testing, particularly literacy skills, developmental time points for testing and methods of data reporting. The role of the cerebellum for cognitive development, especially reading, has been inadequately evaluated in published studies. Recommendations are made to improve assessment methods, and time points for testing, so that reports do not fail to identify children who acquire deficits as they mature through childhood and adolescence. We conclude that claims that radiation treatment for ependymoma administered aged <36 months is associated with limited neurocognitive consequences, are not supported by the literature

    Investigating discrepancies between experimental solid-state NMR and GIPAW calculation : NC–N 13C and OH⋯O 1H chemical shifts in pyridinium fumarates and their cocrystals

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    An NMR crystallography analysis is presented for four solid-state structures of pyridine fumarates and their cocrystals, using crystal structures deposited in the Cambridge Crystallographic Data Centre, CCDC. Experimental one-dimensional, one-pulse 1H and 13C cross-polarisation (CP) magic-angle spinning (MAS) nuclear magnetic resonance (NMR) and two-dimensional 14N–1H heteronuclear multiple-quantum coherence MAS NMR spectra are compared with gauge-including projector augmented wave (GIPAW) calculations of the 1H and 13C chemical shifts and the 14N shifts that additionally depend on the quadrupolar interaction. Considering the high ppm (>10 ppm) 1H resonances, while there is good agreement (within 0.4 ppm) between experiment and GIPAW calculation for the hydrogen-bonded NH moieties, the hydrogen-bonded fumaric acid OH resonances are 1.2–1.9 ppm higher in GIPAW calculation as compared to experiment. For the cocrystals of a salt and a salt formed by 2-amino-5-methylpyridinium and 2-amino-6-methylpyridinium ions, a large discrepancy of 4.2 and 5.9 ppm between experiment and GIPAW calculation is observed for the quaternary ring carbon 13C resonance that is directly bonded to two nitrogens (in the ring and in the amino group). By comparison, there is excellent agreement (within 0.2 ppm) for the quaternary ring carbon 13C resonance directly bonded to the ring nitrogen for the salt and cocrystal of a salt formed by 2,6-lutidinium and 2,5-lutidine, respectively

    Impact of the national rotavirus vaccination programme on acute gastroenteritis in England and associated costs averted.

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    BACKGROUND: Introduction of infant oral rotavirus vaccination in the UK in July 2013 has resulted in decreased hospitalisations and Emergency Department (ED) visits for acute gastroenteritis (AGE), for both adults and children. We investigated reductions in AGE incidence seen in primary care in the two years after vaccine introduction, and estimated the healthcare costs averted across healthcare settings in the first year of the vaccination programme. METHODS: We used primary care data from the Clinical Practice Research Datalink and age-stratified time-series analyses to derive adjusted incidence rate ratios (IRRa) for AGE in the first two years of the post-vaccination era (July 2013-April 2015) compared to the pre-vaccination era (July 2008-June 2013). We estimated cases averted among children aged <5years in the first year of the vaccination programme by comparing observed numbers of AGE cases in 2013-2014 to numbers predicted from the time-series models. We then estimated the healthcare costs averted for general practice consultations, ED visits and hospitalisations. RESULTS: In general practice, AGE rates in infants (the target group for vaccination) decreased by 15% overall after vaccine introduction (IRRa=0.85; 95%CI=0.76-0.95), and by 41% in the months of historically high rotavirus circulation (IRRa=0.59; 95%CI=0.53-0.66). Rates also decreased in other young children and to a lesser degree in older individuals, indicating herd immunity. Across all three settings (general practice, EDs, and hospitalisations) an estimated 87,376 (95% prediction interval: 62,588-113,561) AGE visits by children aged <5years were averted in 2013-14, associated with an estimated £12.5million (9,209-16,198) reduction in healthcare costs. CONCLUSIONS: The marked decreases in the general practice AGE burden after rotavirus vaccine introduction mirror decreases seen in other UK healthcare settings. Overall, these decreases are associated with substantial averted healthcare costs
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