| 1. |
- Algaba, Juan-Carlos, et al.
(författare)
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
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Forskningsöversikt (refereegranskat)abstract
- In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
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| 2. |
- De Guio, François, et al.
(författare)
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Reproducibility and variability of quantitative magnetic resonance imaging markers in cerebral small vessel disease
- 2016
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - 0271-678X. ; 36:8, s. 1319-1337
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Forskningsöversikt (refereegranskat)abstract
- Brain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility of these small vessel disease markers has received little attention despite being widely used in cross-sectional and longitudinal studies. This review focuses on the main small vessel disease-related markers on magnetic resonance imaging including: white matter hyperintensities, lacunes, dilated perivascular spaces, microbleeds, and brain volume. The aim is to summarize, for each marker, what is currently known about: (1) its reproducibility in studies with a scan-rescan procedure either in single or multicenter settings; (2) the acquisition-related sources of variability; and, (3) the techniques used to minimize this variability. Based on the results, we discuss technical and other challenges that need to be overcome in order for these markers to be reliably used as outcome measures in future clinical trials. We also highlight the key points that need to be considered when designing multicenter magnetic resonance imaging studies of small vessel disease.
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| 3. |
- Fazey, Ioan, et al.
(författare)
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Ten essentials for action-oriented and second order energy transitions, transformations and climate change research
- 2018
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Ingår i: Energy Research and Social Science. - : Elsevier BV. - 2214-6296 .- 2214-6326. ; 40, s. 54-70
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Forskningsöversikt (refereegranskat)abstract
- The most critical question for climate research is no longer about the problem, but about how to facilitate the transformative changes necessary to avoid catastrophic climate-induced change. Addressing this question, however, will require massive upscaling of research that can rapidly enhance learning about transformations. Ten essentials for guiding action-oriented transformation and energy research are therefore presented, framed in relation to second-order science. They include: (1) Focus on transformations to low-carbon, resilient living; (2) Focus on solution processes; (3) Focus on ‘how to’ practical knowledge; (4) Approach research as occurring from within the system being intervened; (5) Work with normative aspects; (6) Seek to transcend current thinking; (7) Take a multi-faceted approach to understand and shape change; (8) Acknowledge the value of alternative roles of researchers; (9) Encourage second-order experimentation; and (10) Be reflexive. Joint application of the essentials would create highly adaptive, reflexive, collaborative and impact-oriented research able to enhance capacity to respond to the climate challenge. At present, however, the practice of such approaches is limited and constrained by dominance of other approaches. For wider transformations to low carbon living and energy systems to occur, transformations will therefore also be needed in the way in which knowledge is produced and used.
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| 4. |
- Frisoni, Giovanni B., et al.
(författare)
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European intersocietal recommendations for the biomarker-based diagnosis of neurocognitive disorders
- 2024
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Ingår i: The Lancet Neurology. - 1474-4422 .- 1474-4465. ; 23:3, s. 302-312
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Forskningsöversikt (refereegranskat)abstract
- The recent commercialisation of the first disease-modifying drugs for Alzheimer's disease emphasises the need for consensus recommendations on the rational use of biomarkers to diagnose people with suspected neurocognitive disorders in memory clinics. Most available recommendations and guidelines are either disease-centred or biomarker-centred. A European multidisciplinary taskforce consisting of 22 experts from 11 European scientific societies set out to define the first patient-centred diagnostic workflow that aims to prioritise testing for available biomarkers in individuals attending memory clinics. After an extensive literature review, we used a Delphi consensus procedure to identify 11 clinical syndromes, based on clinical history and examination, neuropsychology, blood tests, structural imaging, and, in some cases, EEG. We recommend first-line and, if needed, second-line testing for biomarkers according to the patient's clinical profile and the results of previous biomarker findings. This diagnostic workflow will promote consistency in the diagnosis of neurocognitive disorders across European countries.
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| 5. |
- Hall, Benjamin, et al.
(författare)
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In vivo tau PET imaging in dementia : Pathophysiology, radiotracer quantification, and a systematic review of clinical findings
- 2017
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Ingår i: Ageing Research Reviews. - : ELSEVIER IRELAND LTD. - 1568-1637 .- 1872-9649. ; 36, s. 50-63
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Forskningsöversikt (refereegranskat)abstract
- In addition to the deposition of beta-amyloid plaques, neurofibrillary tangles composed of aggregated hyperphosphorylated tau are one of the pathological hallmarks of Alzheimer's disease and other neurodegenerative disorders. Until now, our understanding about the natural history and topography of tau deposition has only been based on post-mortem and cerebrospinal fluid studies, and evidence continues to implicate tau as a central driver of downstream neurodegenerative processes and cognitive decline. Recently, it has become possible to assess the regional distribution and severity of tau burden in vivo with the development of novel radiotracers for positron emission tomography (PET) imaging. In this article, we provide a comprehensive discussion of tau pathophysiology, its quantification with novel PET radiotracers, as well as a systematic review of tau PET imaging in normal aging and various dementia conditions: mild cognitive impairment, Alzheimer's disease, frontotemporal dementia, progressive supranuclear palsy, and Lewy body dementia. We discuss the main findings in relation to group differences, clinical-cognitive correlations of tau PET, and multi-modal relationships among tau PET and other pathological markers. Collectively, the small but growing literature of tau PET has yielded consistent anatomical patterns of tau accumulation that recapitulate post-mortem distribution of neurofibrillary tangles which correlate with cognitive functions and other markers of pathology. In general, AD is characterised by increased tracer retention in the inferior temporal lobe, extending into the frontal and parietal regions in more severe cases. It is also noted that the spatial topography of tau accumulation is markedly distinct to that of amyloid burden in aging and AD. Tau PET imaging has also revealed characteristic spatial patterns among various non-AD tauopathies, supporting its potential role for differential diagnosis. Finally, we propose novel directions for future tau research, including (a) longitudinal imaging in preclinical dementia, (b) multi-modal mapping of tau pathology onto other pathological processes such as neuroinflammation, and (c) the need for more validation studies against post-mortem samples of the same subjects. (C) 2017 Elsevier B.V. All rights reserved.
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| 6. |
- O'Brien, John T, et al.
(författare)
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Clinical practice with anti-dementia drugs: a revised (second) consensus statement from the British Association for Psychopharmacology.
- 2011
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Ingår i: Journal of psychopharmacology (Oxford, England). - : SAGE Publications. - 1461-7285 .- 0269-8811. ; 25:8, s. 997-1019
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Forskningsöversikt (refereegranskat)abstract
- The British Association for Psychopharmacology (BAP) coordinated a meeting of experts to review and revise its first (2006) Guidelines for clinical practice with anti-dementia drugs. As before, levels of evidence were rated using accepted standards which were then translated into grades of recommendation A to D, with A having the strongest evidence base (from randomized controlled trials) and D the weakest (case studies or expert opinion). Current clinical diagnostic criteria for dementia have sufficient accuracy to be applied in clinical practice (B) and brain imaging can improve diagnostic accuracy (B). Cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) are effective for mild to moderate Alzheimer's disease (A) and memantine for moderate to severe Alzheimer's disease (A). Until further evidence is available other drugs, including statins, anti-inflammatory drugs, vitamin E and Ginkgo biloba, cannot be recommended either for the treatment or prevention of Alzheimer's disease (A). Neither cholinesterase inhibitors nor memantine are effective in those with mild cognitive impairment (A). Cholinesterase inhibitors are not effective in frontotemporal dementia and may cause agitation (A), though selective serotonin reuptake inhibitors may help behavioural (but not cognitive) features (B). Cholinesterase inhibitors should be used for the treatment of people with Lewy body dementias (Parkinson's disease dementia and dementia with Lewy bodies (DLB)), especially for neuropsychiatric symptoms (A). Cholinesterase inhibitors and memantine can produce cognitive improvements in DLB (A). There is no clear evidence that any intervention can prevent or delay the onset of dementia. Although the consensus statement focuses on medication, psychological interventions can be effective in addition to pharmacotherapy, both for cognitive and non-cognitive symptoms. Many novel pharmacological approaches involving strategies to reduce amyloid and/or tau deposition are in progress. Although results of pivotal studies are awaited, results to date have been equivocal and no disease-modifying agents are either licensed or can be currently recommended for clinical use.
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| 7. |
- Wang, Xin, et al.
(författare)
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Global burden of respiratory infections associated with seasonal influenza in children under 5 years in 2018 : a systematic review and modelling study
- 2020
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Ingår i: The Lancet Global Health. - : Elsevier. - 2214-109X. ; 8:4, s. E497-E510
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Forskningsöversikt (refereegranskat)abstract
- Background: Seasonal influenza virus is a common cause of acute lower respiratory infection (ALRI) in ung children. In 2008, we estimated that 20 million influenza-virus-associated ALRI and 1 million fluenza-virus-associated severe ALRI occurred in children under 5 years globally. Despite this bstantial burden, only a few low-income and middle-income countries have adopted routine influenza ccination policies for children and, where present, these have achieved only low or unknown levels of ccine uptake. Moreover, the influenza burden might have changed due to the emergence and rculation of influenza A/H1N1pdm09. We aimed to incorporate new data to update estimates of the obal number of cases, hospital admissions, and mortality from influenza-virus-associated respiratory fections in children under 5 years in 2018.Methods: We estimated the regional and global burden of influenza-associated respiratory infections in ildren under 5 years from a systematic review of 100 studies published between Jan 1, 1995, and Dec , 2018, and a further 57 high-quality unpublished studies. We adapted the Newcastle-Ottawa Scale to sess the risk of bias. We estimated incidence and hospitalisation rates of influenza-virus-associated spiratory infections by severity, case ascertainment, region, and age. We estimated in-hospital deaths om influenza virus ALRI by combining hospital admissions and in-hospital case-fatality ratios of fluenza virus ALRI. We estimated the upper bound of influenza virus-associated ALRI deaths based on e number of in-hospital deaths, US paediatric influenza-associated death data, and population-based ildhood all-cause pneumonia mortality data in six sites in low-income and lower-middle-income untries.Findings: In 2018, among children under 5 years globally, there were an estimated 109.5 million fluenza virus episodes (uncertainty range [UR] 63.1-190.6), 10.1 million influenza-virus-associated ALRI ses (6.8-15.1); 870 000 influenza-virus-associated ALRI hospital admissions (543 000-1 415 000), 15 300 -hospital deaths (5800-43 800), and up to 34 800 (13 200-97 200) overall influenza-virus-associated ALRI deaths. Influenza virus accounted for 7% of ALRI cases, 5% of ALRI hospital admissions, and 4% of ALRI deaths in children under 5 years. About 23% of the hospital admissions and 36% of the in-hospital deaths were in infants under 6 months. About 82% of the in-hospital deaths occurred in low-income and lower-middle-income countries.Interpretation: A large proportion of the influenza-associated burden occurs among young infants and in low-income and lower middle-income countries. Our findings provide new and important evidence for maternal and paediatric influenza immunisation, and should inform future immunisation policy particularly in low-income and middle-income countries.
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| 8. |
- Wardlaw, Joanna M., et al.
(författare)
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Neuroimaging standards for research into small vessel disease and its contribution to ageing and neurodegeneration
- 2013
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Ingår i: Lancet Neurology. - 1474-4465. ; 12:8, s. 822-838
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Forskningsöversikt (refereegranskat)abstract
- Cerebral small vessel disease (SVD) is a common accompaniment of ageing. Features seen on neuroimaging include recent small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, microbleeds, and brain atrophy. SVD can present as a stroke or cognitive decline, or can have few or no symptoms. SVD frequently coexists with neurodegenerative disease, and can exacerbate cognitive deficits, physical disabilities, and other symptoms of neurodegeneration. Terminology and definitions for imaging the features of SVD vary widely, which is also true for protocols for image acquisition and image analysis. This lack of consistency hampers progress in identifying the contribution of SVD to the pathophysiology and clinical features of common neurodegenerative diseases. We are an international working group from the Centres of Excellence in Neurodegeneration. We completed a structured process to develop definitions and imaging standards for markers and consequences of SVD. We aimed to achieve the following: first, to provide a common advisory about terms and definitions for features visible on MRI; second, to suggest minimum standards for image acquisition and analysis; third, to agree on standards for scientific reporting of changes related to SVD on neuroimaging; and fourth, to review emerging imaging methods for detection and quantification of preclinical manifestations of SVD. Our findings and recommendations apply to research studies, and can be used in the clinical setting to standardise image interpretation, acquisition, and reporting. This Position Paper summarises the main outcomes of this international effort to provide the STandards for Reporting Vascular changes on nEuroimaging (STRIVE).
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| 9. |
- Zanchetti, Alberto, et al.
(författare)
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Blood pressure and low-density lipoprotein-cholesterol lowering for prevention of strokes and cognitive decline: a review of available trial evidence.
- 2014
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Ingår i: Journal of Hypertension. - 1473-5598. ; 32:9, s. 1741-1750
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Forskningsöversikt (refereegranskat)abstract
- It is well established by a large number of randomized controlled trials that lowering blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) by drugs are powerful means to reduce stroke incidence, but the optimal BP and LDL-C levels to be achieved are largely uncertain. Concerning BP targets, two hypotheses are being confronted: first, the lower the BP, the better the treatment outcome, and second, the hypothesis that too low BP values are accompanied by a lower benefit and even higher risk. It is also unknown whether BP lowering and LDL-C lowering have additive beneficial effects for the primary and secondary prevention of stroke, and whether these treatments can prevent cognitive decline after stroke.
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