306 research outputs found
Suitable classification of mortars from ancient roman and renaissance frescoes using thermal analysis and chemometrics
Background
Literature on mortars has mainly focused on the identification and characterization of their components in order to assign them to a specific historical period, after accurate classification. For this purpose, different analytical techniques have been proposed. Aim of the present study was to verify whether the combination of thermal analysis and chemometric methods could be used to obtain a fast but correct classification of ancient mortar samples of different ages (Roman era and Renaissance).
Results
Ancient Roman frescoes from Museo Nazionale Romano (Terme di Diocleziano, Rome, Italy) and Renaissance frescoes from Sistine Chapel and Old Vatican Rooms (Vatican City) were analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). Principal Component analysis (PCA) on the main thermal data evidenced the presence of two clusters, ascribable to the two different ages. Inspection of the loadings allowed to interpret the observed differences in terms of the experimental variables.
Conclusions
PCA allowed differentiating the two kinds of mortars (Roman and Renaissance frescoes), and evidenced how the ancient Roman samples are richer in binder (calcium carbonate) and contain less filler (aggregate) than the Renaissance ones. It was also demonstrated how the coupling of thermoanalytical techniques and chemometric processing proves to be particularly advantageous when a rapid and correct differentiation and classification of cultural heritage samples of various kinds or ages has to be carried out
Correlation between micro and macrostructural biaxial behavior of ascending thoracic aneurysm: a novel experimental technique
Mechanical properties and microstructural modifications of vessel tissues are strongly linked, as established in the state of the art of cardiovascular diseases. Techniques to obtain both mechanical and structural information are reported, but the possibility to obtain real-time microstructural and macrostructural data correlated is still lacking. An experimental approach to characterize the aortic tissue is presented. A setup integrating biaxial traction and Small Angle Light Scattering (SALS) analysis is described. The system was adopted to test ex-vivo aorta specimens from healthy and aneusymatic (aTAA) cases. A significant variation of the fiber dispersion with respect to the unloaded state was encountered during the material traction. The corresponding microstructural and mechanical data were successfully used to fit a given anisotropic constitutive model, with satisfactory R2 values (0.97±0.11 and 0.96±0.17, for aTAA and healthy population, respectively) and fiber dispersion parameters variations between the aTAA and healthy populations (0.39±0.23 and 0.15±0.10). The method integrating the biaxial/SALS technique was validated, allowing for real-time synchronization between mechanical and microstructural analysis of anisotropic biological tissues
Joining participatory approach and spatially-based modelling tools for groundwater resource management.
Although a lot of science has been produced on Water Resource Management (WRM) in the Information and
Communication Technology (ICT) sector, WRM is still poorly addressed via scientific means. Some reasons for
this may be: the underrated importance given to this topic at political and decision-making level; the low-capacity
of the research environment to transfer results; and missing numerical modelling capacities at agencies and
governing authorities.
ICT may provide tools for water planning and management, as discussed within the ICT4WATER cluster initiative.
Among these, GIS-integrated numerical modeling is a robust method to represent hydrological systems and to
provide answers to problems of protection of groundwater resources. Because these tools require a high level
of knowledge pertaining to various disciplines, they are often disregarded as complex “tricky games” providing
unrealistic results. This is a barrier to the uptake of technologies for water management.
To overcome this issue, the application of ICT tools has been combined with an innovative participatory approach,
and large capacity building activities, in the framework of the H2020 FREEWAT project (FREE and open source
software tools for WATer resource management; www.freewat.eu). The major result of the project consists in an
open source and public domain, QGIS-integrated modeling platform for promoting WRM.
FREEWAT capabilities have been demonstrated at 14 case studies in EU and non-EU Countries, where the
effectiveness of few measures foreseen in River Basin Management Plans for achieving good status of water
bodies was tested.
At each case study, a Focus Group (FG) participated by local stakeholders (e.g., river basin authorities, research
institutions, environmental protection agencies, environmental associations) was formed and seven meetings were
organized. During these meetings, the objective of each case study, the methodology to be adopted, including
definition of the conceptual model and of data needed, were discussed. The FG also took decisions on scenarios
to be simulated for testing the feasibility of the foreseen measures. FGs aimed at demonstrating that WRM may
be performed with open source and public domain software and participants’ perception on using ICT tools for
WRM was discussed.
Some of the implemented models are now being used for operational purposes: Vrbansky plato (Slovenia),
where FREEWAT is used to monitor remediation of heating oil spillage and the water supply company intends to
maintain and use developed groundwater flow model for managed groundwater recharge with induced riverbank
filtration; the Bremerhaven case study (Germany), where the local water authority intends to use the developed
groundwater flow model for predictions; the Scarlino-Follonica case study (Italy), where the model will be used by
the regional authority to manage private groundwater remediation projects in a large industrial contaminated site;
the Gozo case study (Malta), where the model is being developed to support the assessment of good groundwater
quantitative status as part of the implementation of the Water Framework Directive
Normal CMR bi-atrial and biventricular reference values in sickle cell disease patients without heart damage
Abstract
Funding Acknowledgements
Type of funding sources: Private company. Main funding source(s): The MIOT project receives "no-profit support" from industrial sponsorships (Chiesi Farmaceutici S.p.A., ApoPharma Inc.).
Background. Cardiac function indices in patients with hemoglobinopathies are different from those in healthy population, mainly due to chronic anemia. Normal reference values specific for SCD patients are not available by CMR.
Aim. We aimed to define the normal cut-off value in SCD patients for bi-atrial and biventricular cardiac magnetic resonance (CMR) parameters.
Methods. We considered forty-eight adult SCD patients with no known risk factors or cardiac disease, normal electrocardiogram, no macroscopic myocardial fibrosis, and all cardiac segments with T2*≥20 ms, consecutively enrolled in the MIOT network (Myocardial iron overload in thalassemia). SCD patients were compared with ninety-six healthy controls and 96 thalassemia major (TM) patients without cardiac damage, both matched for age and gender. Nine pediatric SCD patients were also analysed in comparison with 9 TM patients and 9 healthy subjects matched for age and gender. Cine images were acquired to quantify biventricular function parameters: LV and RV end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV) were normalized for body surface area (EDVI, ESVI, SVI), as well as biventricular mass and atrial areas. Myocardial iron overload was assessed by segmental T2* technique. Late gadolinium enhancement (LGE) images were acquired for evaluation of macroscopic myocardial fibrosis.
Results. In all three groups males showed higher biventricular volumes and mass indexes than females. SCD male patients had significantly higher LVEDVI (p < 0.0001), LVESVI (p = 0.010), LVSVI (p = 0.003), cardiac index (p = 0.002), LV and RV mass index (p = 0.008 and p = 0.001, respectively) and left and right atrial areas (p < 0.001 and p = 0.011) than healthy subjects. No significant differences were found in RVEDVI, EVESVI and biventricular EF. Compared to healthy volunteers, females with SCD showed a larger LVEDVI (p = 0.020), LVSVI (p = 0.039), RV mass index (p = 0.002) and left atrial area (p = 0.008).
SCD and TM patients showed comparable values of bi-atrial and biventricular volumes and function. When compared to TM, SCD patients showed a larger LV (p < 0.001) and RV mass index (p = 0.001) in male group and a larger RV mass index (p = 0.001) in female group. Table 1 shows the cut-offs for bi-atrial and biventricular MR parameters for adult SCD patients by gender.
No significant differences in MR parameters were found among the pediatric groups.
Conclusions. Normal reference ranges of bi-atrial and biventricular MR parameters for adult males and females SCD patients were established. The use of these reference values will prevent possible misdiagnosis of cardiomyopathy in patients with SCD
How early can myocardial iron overload occur in Beta thalassemia major?
BACKGROUND: Myocardial siderosis is the most common cause of death in patients with beta thalassemia major(TM). This study aimed at investigating the occurrence, prevalence and severity of cardiac iron overload in a young Chinese population with beta TM.
METHODS AND RESULTS: We analyzed T2* cardiac magnetic resonance (CMR), left ventricular ejection fraction (LVEF) and serum ferritin (SF) in 201 beta TM patients. The median age was 9 years old. Patients received an average of 13 units of blood per year. The median SF level was 4536 ng/ml and 165 patients (82.1%) had SF>2500 ng/ml. Myocardial iron overload was detected in 68 patients (33.8%) and severe myocardial iron overload was detected in 26 patients (12.6%). Twenty-two patients ≤10 years old had myocardial iron overload, three of whom were only 6 years old. No myocardial iron overload was detected under the age of 6 years. Median LVEF was 64% (measured by CMR in 175 patients). Five of 6 patients with a LVEF<56% and 8 of 10 patients with cardiac disease had myocardial iron overload.
CONCLUSIONS: The TM patients under follow-up at this regional centre in China patients are younger than other reported cohorts, more poorly-chelated, and have a high burden of iron overload. Myocardial siderosis occurred in patients younger than previously reported, and was strongly associated with impaired LVEF and cardiac disease. For such poorly-chelated TM patients, our data shows that the first assessment of cardiac T2* should be performed as early as 6 years old
Feasibility of MR-Based Body Composition Analysis in Large Scale Population Studies
Introduction
Quantitative and accurate measurements of fat and muscle in the body are important for prevention and diagnosis of diseases related to obesity and muscle degeneration. Manually segmenting muscle and fat compartments in MR body-images is laborious and time-consuming, hindering implementation in large cohorts. In the present study, the feasibility and success-rate of a Dixon-based MR scan followed by an intensity-normalised, non-rigid, multi-atlas based segmentation was investigated in a cohort of 3,000 subjects.
Materials and Methods
3,000 participants in the in-depth phenotyping arm of the UK Biobank imaging study underwent a comprehensive MR examination. All subjects were scanned using a 1.5 T MR-scanner with the dual-echo Dixon Vibe protocol, covering neck to knees. Subjects were scanned with six slabs in supine position, without localizer. Automated body composition analysis was performed using the AMRA Profiler™ system, to segment and quantify visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (ASAT) and thigh muscles. Technical quality assurance was performed and a standard set of acceptance/rejection criteria was established. Descriptive statistics were calculated for all volume measurements and quality assurance metrics.
Results
Of the 3,000 subjects, 2,995 (99.83%) were analysable for body fat, 2,828 (94.27%) were analysable when body fat and one thigh was included, and 2,775 (92.50%) were fully analysable for body fat and both thigh muscles. Reasons for not being able to analyse datasets were mainly due to missing slabs in the acquisition, or patient positioned so that large parts of the volume was outside of the field-of-view.
Discussion and Conclusions
In conclusion, this study showed that the rapid UK Biobank MR-protocol was well tolerated by most subjects and sufficiently robust to achieve very high success-rate for body composition analysis. This research has been conducted using the UK Biobank Resource
Lithium suppression of tau induces brain iron accumulation and neurodegeneration
Lithium is a first-line therapy for bipolar affective disorder. However, various adverse effects, including a Parkinson-like hand tremor, often limit its use. The understanding of the neurobiological basis of these side effects is still very limited. Nigral iron elevation is also a feature of Parkinsonian degeneration that may be related to soluble tau reduction. We found that magnetic resonance imaging T2 relaxation time changes in subjects commenced on lithium therapy were consistent with iron elevation. In mice, lithium treatment lowers brain tau levels and increases nigral and cortical iron elevation that is closely associated with neurodegeneration, cognitive loss and parkinsonian features. In neuronal cultures lithium attenuates iron efflux by lowering tau protein that traffics amyloid precursor protein to facilitate iron efflux. Thus, tau- and amyloid protein precursor-knockout mice were protected against lithium-induced iron elevation and neurotoxicity. These findings challenge the appropriateness of lithium as a potential treatment for disorders where brain iron is elevated (for example, Alzheimer’s disease), and may explain lithium-associated motor symptoms in susceptible patients
Reducing pain in children with cancer: Methodology for the development of a clinical practice guideline
Abstract
Although pain is one of the most prevalent and bothersome symptoms children with cancer
experience, evidence-based guidance regarding assessment and management is lacking. With
44 international, multidisciplinary healthcare professionals and nine patient representatives, we
aimed to develop a clinical practice guideline (following GRADE methodology), addressing assessment and pharmacological, psychological, and physical management of tumor-, treatment-, and procedure-related pain in children with cancer. In this paper, we present our thorough methodology for this development, including the challenges we faced and how we approached these. This
lays the foundation for our clinical practice guideline, for which there is a high clinical demand
Evaluation of current algorithms for segmentation of scar tissue from late Gadolinium enhancement cardiovascular magnetic resonance of the left atrium: an open-access grand challenge
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