8,154 research outputs found

    Xenon in Mercury-Manganese Stars

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    Previous studies of elemental abundances in Mercury-Manganese (HgMn) stars have occasionally reported the presence of lines of the ionized rare noble gas Xe II, especially in a few of the hottest stars with Teff ~ 13000--15000 K. A new study of this element has been undertaken using observations from Lick Observatory's Hamilton Echelle Spectrograph. In this work, the spectrum synthesis program UCLSYN has been used to undertake abundance analysis assuming LTE. We find that in the Smith & Dworetsky sample of HgMn stars, Xe is vastly over-abundant in 21 of 22 HgMn stars studied, by factors of 3.1--4.8 dex. There does not appear to be a significant correlation of Xe abundance with Teff. A comparison sample of normal late B stars shows no sign of Xe II lines that could be detected, consistent with the expected weakness of lines at normal abundance. The main reason for the previous lack of widespread detection in HgMn stars is probably due to the strongest lines being at longer wavelengths than the photographic blue. The lines used in this work were 4603.03A, 4844.33A and 5292.22A

    Enteric glia mediate neuron death in colitis through purinergic pathways that require connexin-43 and nitric oxide

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    The concept of enteric glia as regulators of intestinal homeostasis is slowly gaining acceptance as a central concept in neurogastroenterology. Yet how glia contribute to intestinal disease is still poorly understood. Purines generated during inflammation drive enteric neuron death by activating neuronal P2X7 purine receptors (P2X7R), triggering ATP release via neuronal pannexin-1 channels that subsequently recruits intracellular calcium ([Ca(2+)]i) responses in the surrounding enteric glia. We tested the hypothesis that the activation of enteric glia contributes to neuron death during inflammation.We studied neuroinflammation in vivo using the 2,4-dinitrobenzenesulfonic acid model of colitis and in situ using whole-mount preparations of human and mouse intestine. Transgenic mice with a targeted deletion of glial connexin-43 (Cx43) [GFAPāˆ·Cre (ERT2+/-)/Cx43(f/f) ] were used to specifically disrupt glial signaling pathways. Mice deficient in inducible nitric oxide (NO) synthase (iNOS (-/-)) were used to study NO production. Protein expression and oxidative stress were measured using immunohistochemistry and in situ Ca(2+) and NO imaging were used to monitor glial [Ca(2+)]i and [NO]i.Purinergic activation of enteric glia drove [Ca(2+)]i responses and enteric neuron death through a Cx43-dependent mechanism. Neurotoxic Cx43 activity, driven by NO production from glial iNOS, was required for neuron death. Glial Cx43 opening liberated ATP and Cx43-dependent ATP release was potentiated by NO.Our results show that the activation of glial cells in the context of neuroinflammation kills enteric neurons. Mediators of inflammation that include ATP and NO activate neurotoxic pathways that converge on glial Cx43 hemichannels. The glial response to inflammatory mediators might contribute to the development of motility disorders

    Validation of a novel particle isolation procedure using particle doped tissue samples.

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    A novel particle isolation method for tissue samples was developed and tested using particle-doped peri-articular tissues from ovine cadavers. This enabled sensitivity of the isolation technique to be established by doping tissue samples of 0.25 g with very low particle volumes of 2.5 Āµm 3 per sample. Image analysis was used to verify that the method caused no changes to particle size or morphologies

    Recovery rate data for silicon nitride nanoparticle isolation using sodium polytungstate density gradients

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    Ā© 2018 The Authors The average recovery rate of silicon nitride nanoparticles isolated from serum using the method detailed in previous article ā€œA novel method for isolation and recovery of ceramic nanoparticles and metal wear debris from serum lubricants at ultra-low wear rateā€ (Lal et al., 2016) [1] was tested gravimetrically by weighing particles doped into serum before and after the isolation process. An average recovery rate of approximately 89.6% (Ā± 7.1 SD) was achieved

    X-ray Computed Tomography for Failure Mechanism Characterisation within Layered Pouch Cells

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    Lithium-ion battery (LIB) safety is a multi-scale problem: from the whole-cell architecture to its composite internal 3D microstructures. Substantial research is required to standardise failure assessments and optimise cell designs to reduce the risks of LIB failure. In this work, the failure response of a 1 Ah layered pouch cell with a commercially available NMC cathode and graphite anode at 100 % SOC (4.2 V) is investigated. The mechanisms of two abuse methods; mechanical (by nail penetration) and thermal (by accelerating rate calorimetry) are compared by using a suite of post-mortem analysis methods. Post-mortem whole-cell architectural changes and electrode layer deformations were analysed for both mechanisms using non-invasive X-ray computed tomography. Furthermore, changes to electrode surfaces, bulk microstructures and particle morphologies are compared by following a proposed cell disassembly and post-mortem sample preparation methodology. Building on the insights into critical architectural weak points, electrode behaviours and particle cracks, the reliability of X-ray computed tomography as a guide for LIB failure assessment is demonstrated

    Applying the WHO ICF Framework to the Outcome Measures Used in the Evaluation of Long-Term Clinical Outcomes in Coronavirus Outbreaks

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    (1) Objective: The World Health Organizationā€™s (WHO) International Classification of Functioning, Disability and Health (ICF) classification is a unified framework for the description of health and health-related states. This study aimed to use the ICF framework to classify outcome measures used in follow-up studies of coronavirus outbreaks and make recommendations for future studies. (2) Methods: EMBASE, MEDLINE, CINAHL and PsycINFO were systematically searched for original studies assessing clinical outcomes in adult survivors of severe acute respiratory distress syndrome (SARS), middle east respiratory syndrome (MERS) and coronavirus disease-19 (COVID-19) after hospital discharge. Individual items of the identified outcome measures were linked to ICF second-level and third-level categories using ICF linking rules and categorized according to an ICF component. (3) Results: In total, 33 outcome measures were identified from 36 studies. Commonly used (a) ICF body function measures were Pulmonary Function Tests (PFT), Impact of event scale (IES-R) and Hospital Anxiety and Depression Scale (HADS); (b) ICF activity was 6-Minute Walking Distance (6MWD); (c) ICF participation measures included Short Form-36 (SF-36) and St Georgeā€™s Respiratory Questionnaire (SGRQ). ICF environmental factors and personal factors were rarely measured. (4) Conclusions: We recommend future COVID-19 follow-up studies to use the ICF framework to select a combination of outcome measures that capture all the components for a better understanding of the impact on survivors and planning interventions to maximize functional return

    Recovery of low volumes of wear debris from rat stifle joint tissues using a novel particle isolation method

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    Less than optimal particle isolation techniques have impeded analysis of orthopaedic wear debris in vivo. The purpose of this research was to develop and test an improved method for particle isolation from tissue. A volume of 0.018ā€ÆmmĀ³ of clinically relevant CoCrMo, Ti-6Al-4V or Siā‚ƒNā‚„ particles was injected into rat stifle joints for seven days of in vivo exposure. Following sacrifice, particles were located within tissues using histology. The particles were recovered by enzymatic digestion of periarticular tissue with papain and proteinase K, followed by ultracentrifugation using a sodium polytungstate density gradient. Particles were recovered from all samples, observed using SEM and the particle composition was verified using EDX, which demonstrated that all isolated particles were free from contamination. Particle size, aspect ratio and circularity were measured using image analysis software. There were no significant changes to the measured parameters of CoCrMo or Siā‚ƒNā‚„ particles before and after the recovery process (KS tests, pā€Æ>ā€Æ0.05). Titanium particles were too few before and after isolation to analyse statistically, though size and morphologies were similar. Overall the method demonstrated a significant improvement to current particle isolation methods from tissue in terms of sensitivity and efficacy at removal of protein, and has the potential to be used for the isolation of ultra-low wearing total joint replacement materials from periprosthetic tissues

    Systematic review of reviews of symptoms and signs of COVID-19 in children and adolescents

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    OBJECTIVE: To undertake a systematic review of reviews of the prevalence of symptoms and signs of COVID-19 in those aged under 20 years. DESIGN: Narrative systematic review of reviews. PubMed, medRxiv, Europe PMC and COVID-19 Living Evidence Database were searched on 9 October 2020. SETTING: All settings, including hospitalised and community settings. PATIENTS: Children and young people (CYP) under age 20 years with laboratory-proven COVID-19. STUDY REVIEW, DATA EXTRACTION AND QUALITY: Potentially eligible articles were reviewed on title and abstract by one reviewer. Quality was assessed using the modified AMSTARS criteria and data were extracted from included studies by two reviewers. MAIN OUTCOME MEASURES: Prevalence of symptoms and signs of COVID-19. RESULTS: 1325 studies were identified and 18 reviews were included. Eight were high quality, 7 medium and 3 low quality. All reviews were dominated by studies of hospitalised children. The proportion of asymptomatic CYP ranged from 14.6% to 42%. Fever and cough were the the most common symptoms; proportions with fever ranged from 46% to 64.2% and with cough from 32% to 55.9%. All other symptoms or signs including rhinorrhoea, sore throat, headache, fatigue/myalgia and gastrointestinal symptoms including diarrhoea and vomiting were infrequent, occurring in less than 10%-20%. CONCLUSIONS: Fever and cough are the most common symptoms in CYP with COVID-19, with other symptoms infrequent. Further research on symptoms in community samples are needed to inform pragmatic identification and testing programmes for CYP

    Potent anti-inflammatory effects of an H2 S-releasing naproxen (ATB-346) in a human model of inflammation

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    ATB-346 is a hydrogen sulfide-releasing non-steroidal anti-inflammatory drug (H2 S-NSAID) derived from naproxen, which in preclinical studies has been shown to have markedly reduced gastrointestinal adverse effects. However, its anti-inflammatory properties in humans compared to naproxen are yet to be confirmed. To test this, we used a dermal model of acute inflammation in healthy, human volunteers, triggered by ultraviolet-killed Escherichia coli. This robust model allows quantification of the cardinal signs of inflammation along with cellular and humoral factors accumulating within the inflamed skin. ATB-346 was non-inferior to naproxen in terms of its inhibition of cyclooxygenase activity as well as pain and tenderness. ATB-346 significantly inhibited neutrophil infiltration at the site of inflammation at 4Ā h, compared to untreated controls. Subjects treated with ATB-346 also experienced significantly reduced pain and tenderness compared to healthy controls. Furthermore, both classical and intermediate monocyte subsets infiltrating the site of inflammation at 48Ā h expressed significantly lower levels of CD14 compared to untreated controls, demonstrating a shift toward an anti-inflammatory phenotype. Collectively, we have shown for the first time in humans that ATB-346 is potently anti-inflammatory and propose that ATB-346 represents the next generation of H2 S-NSAIDs, as a viable alternative to conventional NSAIDs, with reduced adverse effects profile

    Acetylcholinesterase Inhibitors (AChEI's) for the treatment of visual hallucinations in schizophrenia: a case report

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    Background: Visual hallucinations are commonly seen in various neurological and psychiatric disorders including schizophrenia. Current models of visual processing and studies in diseases including Parkinsons Disease and Lewy Body Dementia propose that Acetylcholine (Ach) plays a pivotal role in our ability to accurately interpret visual stimuli. Depletion of Ach is thought to be associated with visual hallucination generation. AchEIā€™s have been used in the targeted treatment of visual hallucinations in dementia and Parkinsonā€™s Disease patients. In Schizophrenia, it is thought that a similar Ach depletion leads to visual hallucinations and may provide a target for drug treatment Case Presentation: We present a case of a patient with Schizophrenia presenting with treatment resistant and significantly distressing visual hallucinations. After optimising treatment for schizophrenia we used Rivastigmine, an AchEI, as an adjunct to treat her symptoms successfully. Conclusions: This case is the first to illustrate this novel use of an AchEI in the targeted treatment of visual hallucinations in a patient with Schizophrenia. Targeted therapy of this kind can be considered in challenging cases although more evidence is required in this field. Background Visual hallucinations occur in a variety of neurologica
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