49 research outputs found

    Stealth Coronal Mass Ejections from Active Regions

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    Stealth coronal mass ejections (CMEs) are eruptions from the Sun that have no obvious low coronal signature. These CMEs are characteristically slower events, but can still be geoeffective and affect space weather at Earth. Therefore, understanding the science underpinning these eruptions will greatly improve our ability to detect and, eventually, forecast them. We present a study of two stealth CMEs analysed using advanced image processing techniques that reveal their faint signatures in observations from the extreme ultraviolet (EUV) imagers onboard the Solar and Heliospheric Observatory (SOHO), Solar Dynamics Observatory (SDO), and Solar Terrestrial Relations Observatory (STEREO) spacecraft. The different viewpoints given by these spacecraft provide the opportunity to study each eruption from above and the side contemporaneously. For each event, EUV and magnetogram observations were combined to reveal the coronal structure that erupted. For one event, the observations indicate the presence of a magnetic flux rope before the CME's fast rise phase. We found that both events originated in active regions and are likely to be sympathetic CMEs triggered by a nearby eruption. We discuss the physical processes that occurred in the time leading up to the onset of each stealth CME and conclude that these eruptions are part of the low-energy and velocity tail of a distribution of CME events, and are not a distinct phenomenon.Comment: 20 pages, 10 figures, accepted for publication in The Astrophysical Journa

    Investigating Remote-sensing Techniques to Reveal Stealth Coronal Mass Ejections

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    Eruptions of coronal mass ejections (CMEs) from the Sun are usually associated with a number of signatures that can be identified in solar disc imagery. However, there are cases in which a CME that is well observed in coronagraph data is missing a clear low-coronal counterpart. These events have received attention during recent years, mainly as a result of the increased availability of multi-point observations, and are now known as 'stealth CMEs'. In this work, we analyse examples of stealth CMEs featuring various levels of ambiguity. All the selected case studies produced a large-scale CME detected by coronagraphs and were observed from at least one secondary viewpoint, enabling a priori knowledge of their approximate source region. To each event, we apply several image processing and geometric techniques with the aim to evaluate whether such methods can provide additional information compared to the study of "normal" intensity images. We are able to identify at least weak eruptive signatures for all events upon careful investigation of remote-sensing data, noting that differently processed images may be needed to properly interpret and analyse elusive observations. We also find that the effectiveness of geometric techniques strongly depends on the CME propagation direction with respect to the observers and the relative spacecraft separation. Being able to observe and therefore forecast stealth CMEs is of great importance in the context of space weather, since such events are occasionally the solar counterparts of so-called 'problem geomagnetic storms'.Comment: 26 pages, 8 figures, 1 table, accepted for publication in Frontiers in Astronomy and Space Science

    Circulating oncometabolite 2-hydroxyglutarate (2HG) as a potential biomarker for isocitrate dehydrogenase (IDH1/2) mutant cholangiocarcinoma

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    Isocitrate dehydrogenase (IDH) enzymes catalyze the decarboxylation of isocitrate to alpha-ketoglutarate. IDH1/2 mutations preferentially convert αKG to R-2-hydroxyglutarate (R2HG), resulting in R2HG accumulation in tumor tissues. We investigated circulating 2-hydroxyglutate (2HG) as potential biomarkers for patients with IDH-mutant (IDHmt) cholangiocarcinoma (CCA). R2HG and S-2-hydroxyglutarate (S2HG) levels in blood and tumor tissues were analyzed in a discovery cohort of IDHmt glioma and CCA patients. Results were validated in cohorts of CCA and clear cell renal cell carcinoma (ccRCC) patients. The R2HG/S2HG ratio (rRS) was significantly elevated in tumor tissues, but not in blood for IDHmt glioma patients, while circulating rRS was elevated in IDHmt CCA patients. There were overlap distributions of circulating R2HG and total 2HG (t2HG) in both IDHmt and wild-type (IDHwt) CCA patients, while there was minimal overlap in rRS values between IDHmt and IDHwt CCA patients. Using the rRS cut-off value of 1.5, the sensitivity of rRS was 90% and specificity was 96.8%. Circulating rRS is significantly increased in IDHmt CCA patients compare to IDHwt CCA patients. Circulating rRS is a sensitive and specific surrogate biomarker for IDH1/2 mutations in CCA. It can potentially be used as a tool for monitoring IDH-targeted therapy

    Repair of Acute Respiratory Distress Syndrome in COVID-19 by Stromal Cells (REALIST-COVID Trial):A Multicentre, Randomised, Controlled Trial

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    RationaleMesenchymal stromal cells (MSCs) may modulate inflammation, promoting repair in COVID-19-related Acute Respiratory Distress Syndrome (ARDS).ObjectivesWe investigated safety and efficacy of ORBCEL-C (CD362-enriched, umbilical cord-derived MSCs) in COVID-related ARDS.MethodsThis multicentre, randomised, double-blind, allocation concealed, placebo-controlled trial (NCT03042143) randomised patients with moderate-to-severe COVID-related ARDS to receive ORBCEL-C (400million cells) or placebo (Plasma-Lyte148).MeasurementsThe primary safety and efficacy outcomes were incidence of serious adverse events and oxygenation index at day 7 respectively. Secondary outcomes included respiratory compliance, driving pressure, PaO2/FiO2 ratio and SOFA score. Clinical outcomes relating to duration of ventilation, length of intensive care unit and hospital stays, and mortality were collected. Long-term follow up included diagnosis of interstitial lung disease at 1 year, and significant medical events and mortality at 2 years. Transcriptomic analysis was performed on whole blood at day 0, 4 and 7.Main results60 participants were recruited (final analysis n=30 ORBCEL-C, n=29 placebo: 1 in placebo group withdrew consent). 6 serious adverse events occurred in the ORBCEL-C and 3 in the placebo group, RR 2.9(0.6-13.2)p=0.25. Day 7 mean[SD] oxygenation index did not differ (ORBCEL-C 98.357.2], placebo 96.667.3). There were no differences in secondary surrogate outcomes, nor mortality at day 28, day 90, 1 or 2 years. There was no difference in prevalence of interstitial lung disease at 1year nor significant medical events up to 2 years. ORBCEL-C modulated the peripheral blood transcriptome.ConclusionORBCEL-C MSCs were safe in moderate-to-severe COVID-related ARDS, but did not improve surrogates of pulmonary organ dysfunction. Clinical trial registration available at www.Clinicaltrialsgov, ID: NCT03042143. This article is open access and distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/)

    UGT1A1 sequence variants and bilirubin levels in early postnatal life: a quantitative approach

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    <p>Abstract</p> <p>Background</p> <p>Fundamental to definitively identifying neonates at risk of developing significant hyperbilirubinemia is a better understanding of the genetic factors associated with early bilirubin rise. Previous genetic studies have focused on the UGT1A1 gene, associating common variation in the coding or promoter regions with qualitative assessments of bilirubin (i.e. significantly elevated or not). These studies have had conflicting results and limited success. We chose to approach the problem by focusing on the quantitative (absolute) change in bilirubin levels early in post-natal life. We apply this approach to the UGT1A1 gene - exploring the contribution of both rare and common variants to early bilirubin changes.</p> <p>Methods</p> <p>We sequenced the exons, PBREM, 5'-, and 3'- regions of the UGT1A1 gene in 80 otherwise healthy term neonates who had repeat bilirubin levels measured within the first five days of life.</p> <p>Results</p> <p>Three novel coding variants were observed, but there was no clear relationship between rare coding variants and bilirubin rise. Adjusted linear regression models fit to evaluate the relationship between changing bilirubin levels and common UGT1A1variants found that among 39 neonates whose bilirubin was resampled within 33 hours, individuals homozygous for the mutant allele of a 3'UTR SNP had significantly smaller changes in bilirubin (P = 0.003) than individuals carrying the wild-type allele.</p> <p>Conclusions</p> <p>Collectively, rare UGT1A1 coding variants do not appear to play a prominent role in determining early bilirubin levels; however common variants in the 3' UTR of UGT1A1 may modulate the early bilirubin rise. A quantitative approach to evaluating early bilirubin kinetics provides a more robust framework in which to better understand the genetics of neonatal hyperbilirubinemia.</p

    Realising the full potential of data-enabled trials in the UK : a call for action

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    Rationale: Clinical trials are the gold standard for testing interventions. COVID-19 has further raised their public profile, and emphasised the need to deliver better, faster, more efficient trials for patient benefit. Considerable overlap exists between data required for trials and data already collected routinely inelectronic healthcare records (EHR). Opportunities exist to utilise these in innovative ways to decrease duplication of effort, and speed trial recruitment, conduct and follow-up. Approach: The National Institute of Health Research (NIHR), Health Data Research UK (HDR UK) and Clinical Practice Research Datalink (CPRD) co-organised a national workshop to accelerate the agenda for “data-enabled clinical trials”. Showcasing successful examples and imagining future possibilities, the plenary talks, panel discussions, group discussions and case studies covered: design/feasibility; recruitment; conduct/follow-up; collecting benefits/harms; and analysis/interpretation. Reflection: Some notable studies have successfully accessed and used EHR to identify potential recruits, support randomised trials, deliver interventions and supplement/replace trial-specific follow-up. Some outcome measures are already reliably collected; others, like safety, need detailed work to meet regulatory reporting requirements. There is a clear need for system interoperability and a “route map” to identify and access the necessary datasets. Researchers running regulatory-facing trials must carefully consider how data quality and integrity would be assessed. An experience-sharing forum could stimulate wider adoption of EHR-based methods in trial design and execution. Discussion: EHR offer opportunities to better plan clinical trials, assess patients and capture data more efficiently, reducing research waste and increasing focus on each trial’s specific challenges. The short-term emphasis should be on facilitating patient recruitment and for post-marketing authorisation trials where research-relevant outcome measures are readily collectable. Sharing of case studies is encouraged. The workshop directly informed NIHR’s funding call. ambitious data-enabled trials at scale. There is the opportunity for the United Kingdom to build upon existing data science capabilities to identify, recruit and monitor patients in trials at scale

    Ethical issues, research and vulnerability : gaining the views of children and young people in residential care

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    Children and young people in residential care are some of the most vulnerable in our society. They may have experienced violence and physical, sexual or emotional abuse. They may be involved in offending or the misuse of drugs and alcohol. They are separated from their families and have to cope with living in a group situation with other young people and staff members. Children and young people in residential care also possess strengths, competencies and resilience. We have much to learn from their experiences and perspectives, both generally and surrounding their time in care. This paper will address the ethical issues which arise from gaining the views of children and young people in residential care, drawing on the experience of carrying out three studies in particular (Kendrick et al. 2004, The development of a residential unit working with sexually aggressive young men. In: H.G. Eriksson and T. Tjelflaat, eds. Residential care: horizons for the new century. Aldershot: Ashgate, 38-55; Docherty et al. 2006, Designing with care: interior design and residential child care. Farm7 and SIRCC. http://www.sircc.strath.ac.uk/publications/Designing_with_Care.pdf; Steckley, L. and Kendrick, A., 2005. Physical restraint in residential child care: the experiences of young people and residential workers. Childhoods 2005: Children and Youth in Emerging and Transforming Societies, University of Oslo, Norway, 29 June-3 July 2005, Steckley and Kendrick 2007, Young people's experiences of physical restraint in residential care: subtlety and complexity in policy and practice. In: M. Nunno, L. Bullard and D. Day, eds. For our own safety: examining the safety of high-risk interventions for children and young people. Washington, DC: Child Welfare League of America, forthcoming). The paper will discuss: information, consent and choice about involvement in the research; confidentiality, privacy and safety. It will also explore some of the more complex issues of ethical good practice which arise from researching children in their own living space. The negotiation of children's time and space must be approached carefully, with consideration of their rights and wishes. Sensitivity to children and young people's priorities and preoccupations must be paramount
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