X-Ray Computed Tomography In Situ: An Opportunity for Museums and Restoration Laboratories

X-ray Computed Tomography (X-ray CT) is a sophisticated non-destructive imaging technique to investigate structures and materials of complex objects, and its application can answer many conservation and restoration questions. However, for Cultural Heritage investigations, medical CT scanners are not optimized for many case-studies: These instruments are designed for the human body, are not flexible and are difficult to use in situ. To overcome these limitations and to safely investigate works of art on site\u2014in a restoration laboratory or in a museum\u2014the X-ray Tomography Laboratory of the University of Bologna designed several CT systems. Here we present two of these facilities and the results of important measurement campaigns performed in situ. The first instrument, light and flexible, is designed to investigate medium-size objects with a resolution of a few tens of microns and was used for the CT analysis of several Japanese theater masks belonging to the collection of the \u201cL. Pigorini\u201d Museum (Rome). The second is designed to analyze larger objects, up to 200 cm and was used to investigate the collection of the so-called \u201cStatue Vestite\u201d (devotional dressed statues) of the Diocesan Museum of Massa

SYSTEM FOR AUTOMATIC DETECTION OF CLUSTERED MICROCALCIFICATIONS IN DIGITAL MAMMOGRAMS

In this paper, we investigate the performance of a Computer Aided Diagnosis (CAD) system for the detection of clustered microcalcifications in mammograms. Our detection algorithm consists of the combination of two different methods. The first, based on difference-image techniques and gaussianity statistical tests, finds out the most obvious signals. The second, is able to discover more subtle microcalcifications by exploiting a multiresolution analysis by means of the wavelet transform. We can separately tune the two methods, so that each one of them is able to detect signals with similar features. By combining signals coming out from the two parts through a logical OR operation, we can discover microcalcifications with different characteristics. Our algorithm yields a sensitivity of 91.4% with 0.4 false positive cluster per image on the 40 images of the Nijmegen database

Identification and modelling of a GT-A fold in the α-dystroglycan glycosylating enzyme LARGE1

LARGE xylosyl- and glucuronyltransferase 1 (LARGE1)is an enzyme responsible for the final steps of the post-translational modifications of dystroglycan (DG), a membrane receptor that links the cytoskeleton with the extracellular matrix in skeletal muscle and in a variety of other tissues. LARGE1 acts by adding the repeating disaccharide unit [-3Xyl-\u3b11,3GlcA\u3b21-] to the extracellular portion of the DG complex (\u3b1-DG); defects in the LARGE1 gene result in an aberrant glycosylation of \u3b1-DG and consequent impairment of its binding to laminin, eventually affecting the connection between the cell and the extracellular environment. In skeletal muscle, this leads to degeneration of the muscular tissue and muscular dystrophy. So far, a few missense mutations have been identified within the LARGE1 protein and linked to congenital muscular dystrophy and, since no structural information is available on this enzyme, our understanding of the molecular mechanisms underlying these pathologies is still very limited. Here, we generated a 3D model structure of the two catalytic domains of LARGE1, combining different molecular modelling approaches. Furthermore, by using molecular dynamics simulations we analyzed the effect on the structure and stability of the first catalytic domain of the pathological missense mutation S331F that gives rise to a severe form of muscle-eye-brain disease

Extraction of the Jugular Venous Pulse and carotid profile using a cervical contact plethysmography system

The Jugular Venous Pulse (JVP) is considered a reliable parameter for the assessment of Central Venous Pressure (CVP). Here, the functionality of a cervical contact plethysmography system designed for non-invasive and operator-independent acquisition of the JVP signal, is shown. To validate the signal, it was recorded in supine and sitting positions, together with the reference Electrocardiography (ECG), on 26 healthy subjects. In the supine acquired signal, the characteristic JVP waves (a, c, v) and the negative deflections (x, y) are well recognizable. In the sitting recorded signal, the systolic peak b and the d incisura of the Common Carotid Artery (CCA) waveform are recognized. For each signal, we calculated the Fraction of the Cardiac Cycle (ccf) represented by the time intervals between the JVP peaks and the ECG peaks, in the form: ΔtaP, ΔtcR, ΔtxP, ΔtvT, Δtyv, Δtvx, and Δtxa. The same was done for the CCA waveform, in the form: ΔtbS, ΔtbT, Δtdb, ΔtdS, and ΔtdT. This system could mitigate risks and costs associated with central venous catheterization and its potential extends to applications in telemedicine, sports medicine, and space medicine

X-ray computed microtomography: A non-invasive and time-efficient method for identifying and screening Roman copper-based coins

This study utilises X-ray Computed Micro-Tomography (μXCT) as a non-destructive and non-invasive method to recover the original surface features and reveal the characteristics of encrusted, illegible Roman copper-based coins before any physical cleaning process is performed. The coins were retrieved from the topsoil during an archaeological survey in the countryside of the ancient city of Aquileia, Italy, and were severely degraded, covered with accumulated matter and pronounced encrustations developed over centuries of aging buried in soil. Despite their condition, most of the coins were identified from a numismatic standpoint using tomographic data alone, with the aid of reference images. They were subsequently cleaned using traditional manual methods and the results compared with μXCT. X-ray Fluorescence (XRF) analysis of the coins after the physical cleaning confirmed their numismatic attribution and revealed information regarding the influence of different alloy compositions on the applicability of the μXCT method, as well as on the corrosion process of the coins. This study showcases how the application of μXCT on fragile corroded metal artifacts prior to any intrusive manual procedures can expedite the identification process, mitigating the risk of information loss caused by physical handling and cleaning. This approach proves particularly valuable when dealing with large numbers of coins that would typically require restoration for identification purposes. It also emphasises the numerous advantages of using μXCT for coin identification, provenance determination, dating, virtual restoration, digitisation, and long-term preservation

X-ray tomography of large wooden artworks: The case study of "Doppio corpo" by Pietro Piffetti

n/

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

Il calcolo parallelo al servizio della tomografia 3D

Il calcolo parallelo al servizio della tomografia 3D: ideazione e sviluppo di software user frendly per l'elaborazione parallela dei dati tomografic