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4 - Methods and Materials of the Amsterdam Sunflowers
- Edited by Muriel Geldof, Maarten van Bommel, Marije Vellekoop, Ella Hendriks
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- Book:
- Van Gogh's Sunflowers Illuminated
- Published by:
- Amsterdam University Press
- Published online:
- 25 November 2020
- Print publication:
- 21 June 2019, pp 85-124
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Summary
Introduction
This chapter explains the materials and techniques employed in the Amsterdam Sunflowers, enabling a comparison with the London version described in chapter 3. Building upon the 2016 article published in the National Gallery Technical Bulletin, it incorporates the latest findings gained by computer-assisted methods used to characterize the canvas support, as well as in-situ campaigns of non-invasive investigation together with further analysis of microscopic paint samples. The chapter sequence follows the steps in Van Gogh's working practice. Starting with the canvas, automated analysis of the weave enables the provenance of the canvas to be traced back to a particular roll of linen ordered by Van Gogh. Combining technical evidence with knowledge of historical manufacturing techniques further allows us to reconstruct the way in which Van Gogh divided his canvas roll into pieces used for Sunflowers and other paintings. We go on to consider how, with the original painting at hand, he used charcoal to transfer the motif of the London Sunflowers onto his blank canvas. Despite careful planning of the composition, an adjustment was required late in the working process, when Van Gogh added a painted wooden strip to extend the background above the flower at the top edge of the canvas. The artist's process of working up the composition in paint is described, paying special attention to his use of colour. The pigments and pigment mixtures used in the Amsterdam Sunflowers have been comprehensively mapped and are compared with the London picture, with discussion of some similarities and differences that account for the distinctive colour scheme of each painting. This understanding of colour application in the Amsterdam Sunflowers lays the foundation for subsequent chapters that will go on to consider the impact of light-induced colour changes that have taken place over time, and the related need to define appropriate lighting guidelines for the future safe preservation of this painting and others made with similar materials (chapters 5 and 7).
Canvas
Studying the physical characteristics of canvas picture supports is an established means of acquiring valuable information about a painter's working methods. The canvas itself is hidden by paint on the front and a second canvas is often applied to its reverse for added support.
Cerebrospinal fluid biomarkers in patients with central nervous system infections: a retrospective study
- Alessandro Di Stefano, Chiara Alcantarini, Cristiana Atzori, Filippo Lipani, Daniele Imperiale, Elisa Burdino, Sabrina Audagnotto, Lorenzo Mighetto, Maria Grazia Milia, Giovanni Di Perri, Andrea Calcagno
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- Journal:
- CNS Spectrums / Volume 25 / Issue 3 / June 2020
- Published online by Cambridge University Press:
- 27 May 2019, pp. 402-408
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Background
Central nervous system (CNS) may be infected by several agents, resulting in different presentations and outcomes. Analysis of cerebrospinal fluid (CSF) markers could be helpful to differentiate specific conditions and setting an appropriate therapy.
MethodsPatients presenting with signs and symptoms were enrolled if, before receiving a diagnostic lumbar puncture, signed a written informed consent. We analyzed CSF indexes of blood–brain barrier permeability (CSF to serum albumin ratio or CSAR), inflammation (CSF to serum IgG ratio, neopterin), amyloid deposition (1–42 β-amyloid), neuronal damage (Total tau (T-tau), Phosphorylated tau (P-tau), and 14.3.3 protein) and astrocyte damage (S-100β).
ResultsTwo hundred and eighty-one patients were included: they were mainly affected by herpesvirus encephalitis, enterovirus meningoencephalitis, bacterial meningitis (Neisseria meningitidis and Streptococcus pneumoniae), and infection by other etiological agents or unknown pathogen. Their CSF features were compared with HIV-negative patients and native HIV-positive individuals without CNS involvement. 14.3.3 protein was found in bacterial and HSV infections while T-tau and neopterin were abnormally high in the herpesvirus group. P-tau, instead, was elevated in enterovirus meningitis. S-100β was found to be high in patients with HSV-1 and HSV-2 infections but not in those with Varicella Zoster Virus (VZV). Thirty-day mortality was unexpectedly low (2.7%): patients who died had higher levels of T-tau and, significantly, lower levels of Aβ1–42.
ConclusionThis work demonstrates that CSF biomarkers of neuronal damage or inflammation may vary during CNS infections according to different causative agents. The prognostic value of these biomarkers needs to be assessed in prospective studies.
VP17 Hepatitis C Virus Treatment: A Meta-Analysis Of Long-Term Efficacy
- Chiara Inserra, Sophia Campbell Davies, Mariagrazia Piacenza, Angelo Bignamini, Paola Minghetti, Grazia Zerega
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- Journal:
- International Journal of Technology Assessment in Health Care / Volume 34 / Issue S1 / 2018
- Published online by Cambridge University Press:
- 03 January 2019, pp. 162-163
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Introduction:
The efficacy of second generation direct-acting antiviral agents (DAAs-2), in terms of sustained viral response (SVR) 12 weeks after the end of treatment (EOT), has widely been proven; however, long-term efficacy is still controversial due to the low number of available studies with a small number of patients. The objective of this study is to conduct a systematic review and, if possible, a meta-analysis of existing clinical evidence of the long-term efficacy (SVR longer than 12 weeks after EOT) of DAAs-2 for hepatitis C virus (HCV) treatment.
Methods:A systematic review was performed with the use of CENTRAL, MEDLINE, Embase, Pubmed and SBBL-CILEA/METACRAWLER databases. Trials were initially screened by the title; secondly, full papers and abstracts were analysed. The meta-analysis included randomised controlled trials (RCTs) with adult patients affected by HCV, treated with DAAs-2 and assessed for longer than 12 weeks after EOT. Study quality assessment was undertaken using the Jadad scale. Heterogeneity analysis of the studies was conducted with chi-square and I2. The statistical analysis of the efficacy rate was performed using the meta package with the R software. The effect estimate was expressed in risk ratio (RR) with 95% confidence interval (CI 95%) and pooled using a random effects model.
Results:Of the 106 identified studies, 11 high quality RCTs were included for meta-analysis (25 were duplicate publications, 70 did not meet the inclusion criteria). Considered genotypes were 1 (n = 9), 2 (n = 1), 3 (n = 1). Meta-analysis included 3,720 patients (2,698 treated with DAAs-2; 1,022 treated with placebo or a first generation DAA±Ribavirin±Pegylated interferon). Heterogeneity between studies was high (p<0.001; I2 = 90.2%); however, it was absorbed by the model (τ2 = 0,08). Long-term efficacy was expressed as SVR 24 weeks after EOT, since longer timescales were not available. According to the pooled RR, the incidence of efficacy was 1.5 (CI 95%: 1.24−1.83, p < 0.001).
Conclusions:The meta-analysis demonstrated that DAAs-2 for HCV treatment have long-term efficacy at SVR 24 weeks after the EOT; however, the number of studies is mostly based on genotype 1. More RCTs are required to confirm long-term efficacy at more than six months after EOT for all treated genotypes.
Validity and reliability of the Palliative Care Transition Measure for Caregivers (PCTM-C)
- Daniela D'Angelo, Chiara Mastroianni, Marco Artico, Valentina Biagioli, Roberto Latina, Michela Guarda, Michela Piredda, Maria Grazia De Marinis
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- Journal:
- Palliative & Supportive Care / Volume 17 / Issue 2 / April 2019
- Published online by Cambridge University Press:
- 21 January 2018, pp. 202-207
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Objective
Patients suffering from advanced disease face different care transitions. The transition from acute to palliative care is challenging and may lead to the discontinuity of care. Family caregivers become important sources of information, as patients begin to experience difficulties in coping with emotional transition events. The Care Transition Measure was developed to evaluate care transitions as experienced by the elderly. It has never been used in palliative care. The aim of this study was to test the validity and reliability of a modified version of the Palliative Care Transition Measure, specifically the Palliative Care Transition Measure for Caregivers (PCTM-C).
MethodThe study included two main phases. Phase I focused on the construction of a modified version of the Palliative Care Transition Measure through two focus groups and by computing the content validity index. Phase II focused on testing the psychometric properties of the PCTM-C on 272 family caregivers through confirmatory factor analysis.
ResultThe content validity index for each of the items was higher than 0.80, whereas that for the scale was 0.95. The model tested with confirmatory factor analysis fitted the data well and confirmed that the transition measures referred to communication, integrated care and a trusting-relationship, and therefore the core dimensions of continuity according to existing conceptual models. The internal consistency was high (Cronbach's alpha = 0.94).
Significance of resultsThe PCTM-C proved to be a suitable measure of the quality of such transitions. It may be used in clinical practice as a continuity quality indicator and has the potential to guide interventions to enhance family caregivers’ experience of care continuity.
Radio Continuum Surveys with Square Kilometre Array Pathfinders
- Part of
- Ray P. Norris, J. Afonso, D. Bacon, Rainer Beck, Martin Bell, R. J. Beswick, Philip Best, Sanjay Bhatnagar, Annalisa Bonafede, Gianfranco Brunetti, Tamás Budavári, Rossella Cassano, J. J. Condon, Catherine Cress, Arwa Dabbech, I. Feain, Rob Fender, Chiara Ferrari, B. M. Gaensler, G. Giovannini, Marijke Haverkorn, George Heald, Kurt Van der Heyden, A. M. Hopkins, M. Jarvis, Melanie Johnston-Hollitt, Roland Kothes, Huib Van Langevelde, Joseph Lazio, Minnie Y. Mao, Alejo Martínez-Sansigre, David Mary, Kim Mcalpine, E. Middelberg, Eric Murphy, P. Padovani, Zsolt Paragi, I. Prandoni, A. Raccanelli, Emma Rigby, I. G. Roseboom, H. Röttgering, Jose Sabater, Mara Salvato, Anna M. M. Scaife, Richard Schilizzi, N. Seymour, Dan J. B. Smith, Grazia Umana, G.-B. Zhao, Peter-Christian Zinn
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- Journal:
- Publications of the Astronomical Society of Australia / Volume 30 / 2013
- Published online by Cambridge University Press:
- 27 March 2013, e020
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In the lead-up to the Square Kilometre Array (SKA) project, several next-generation radio telescopes and upgrades are already being built around the world. These include APERTIF (The Netherlands), ASKAP (Australia), e-MERLIN (UK), VLA (USA), e-EVN (based in Europe), LOFAR (The Netherlands), MeerKAT (South Africa), and the Murchison Widefield Array. Each of these new instruments has different strengths, and coordination of surveys between them can help maximise the science from each of them. A radio continuum survey is being planned on each of them with the primary science objective of understanding the formation and evolution of galaxies over cosmic time, and the cosmological parameters and large-scale structures which drive it. In pursuit of this objective, the different teams are developing a variety of new techniques, and refining existing ones. To achieve these exciting scientific goals, many technical challenges must be addressed by the survey instruments. Given the limited resources of the global radio-astronomical community, it is essential that we pool our skills and knowledge. We do not have sufficient resources to enjoy the luxury of re-inventing wheels. We face significant challenges in calibration, imaging, source extraction and measurement, classification and cross-identification, redshift determination, stacking, and data-intensive research. As these instruments extend the observational parameters, we will face further unexpected challenges in calibration, imaging, and interpretation. If we are to realise the full scientific potential of these expensive instruments, it is essential that we devote enough resources and careful study to understanding the instrumental effects and how they will affect the data. We have established an SKA Radio Continuum Survey working group, whose prime role is to maximise science from these instruments by ensuring we share resources and expertise across the projects. Here we describe these projects, their science goals, and the technical challenges which are being addressed to maximise the science return.