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In 1H NMR (nuclear magnetic resonance) relaxation measurements for a set of eight hardwood and softwood samples, each free induction decay (FID) is fitted by the sum of a “solid” signal of the form A exp[-c(t/TS)2][1-g(t/TS)2+h(t/TS)4] plus a “liquid” signal B exp(-t/T2-FID). Distributions of longitudinal (T1) relaxation times were computed separately for the solid and liquid components, giving also the solid/liquid 1H ratio α. From measurements on the samples dried, seasoned, and hydrated, the moisture content (liquid/solid weight ratio) was found to be approximately 0.50/α. For each of the “seasoned” samples (10%–13% moisture content) a single T1 peak was found for the solid and two for the liquid, with the longer liquid T1 close to that of the solid, but with some differences exceeding perceived experimental uncertainties. None of the solid or liquid-long T1’s is much less than 20 ms, even though liquid-short times go as low as 0.35 ms, appearing to negate simple solid-to-liquid exchange on a millisecond time scale. Data for six of the samples (all except for two resin-containing pine species) can be formally fitted by a two-site exchange model, in which cases the solid-to-liquid exchange times are a few tens of milliseconds. For our set of wood samples, each of the above three T1 values, and also the overall liquid geometric-mean and rate-average T1’s, as well as the liquid long-T1 fraction, for a seasoned hardwood is longer than the corresponding value for any softwood, suggesting that relaxation parameters may provide a useful ranking of seasoned woods. [ABSTRACT FROM AUTHOR]

In recent years many papers about diagnostic applications of diffusion tensor imaging (DTI) have been published. This is because DTI allows to evaluate in vivo and in a non-invasive way the process of diffusion of water molecules in biological tissues. However, the simplified description of the diffusion process assumed in DTI does not permit to completely map the complex underlying cellular components and structures, which hinder and restrict the diffusion of water molecules. These limitations can be partially overcome by means of diffusion kurtosis imaging (DKI). The aim of this paper is the description of the theory of DKI, a new topic of growing interest in radiology. DKI is a higher order diffusion model that is a straightforward extension of the DTI model. Here, we analyze the physics underlying this method, we report our MRI acquisition protocol with the preprocessing pipeline used and the DKI parametric maps obtained on a 1.5 T scanner, and we review the most relevant clinical applications of this technique in various neurological diseases. [ABSTRACT FROM AUTHOR]

The radiation therapy carried out by means of heavy charged particles (such as carbon ions) and neutrons is rapidly becoming widespread worldwide. The success of these radiation therapies relies on the high density of energy released by these particles or by secondary particles produced after primary interaction with matter. The biological damages produced by ionising radiations in tissues and cells depend more properly on the energy released per unit pathlength, which is the linear energy transfer and which determines the radiation quality. To improve the therapy effectiveness, it is necessary to grasp the mechanisms of free radical production and distribution after irradiation with these particles when compared with the photon beams. In this work some preliminary results on the analysis of the spatial distributions of the free radicals produced after exposure of ammonium tartrate crystals to various radiation beams (60Co gamma photons and thermal neutrons) were reported. Electron spin resonance analyses were performed by the electron spin echo technique, which allows the determination of local spin concentrations and by double electron–electron resonance technique, which is able to measure the spatial distance distribution (range 1.5–8 nm) among pairs of radicals in solids. The results of these analyses are discussed on the basis of the different distributions of free radicals produced by the two different radiation beams used. [ABSTRACT FROM AUTHOR]

This paper reports on results obtained by electron paramagnetic resonance (EPR) measurements and Monte Carlo (MC) simulation on a blend of alanine added with low content of gadolinium oxide (5 % by weight) to improve the sensitivity to thermal neutron without excessively affecting tissue equivalence. The sensitivity is enhanced by this doping procedure of more an order of magnitude. The results are compared with those obtained with the addition of boric acid (50 % by weight) where boron is in its natural isotopic composition in order to produce low-cost EPR dosemeters. The gadolinium addition influences neutron sensitivity more than the boron addition. The presence of additives does not substantially change the fading of the EPR signal induced by neutrons. The MC simulations agree the experimental results in case of gadolinium addition. [ABSTRACT FROM AUTHOR]

This paper continues analyses on organic compounds for application in neutron dosimetry performed through electron spin resonance (ESR). Here, the authors present the results obtained by ESR measurements of a blend of ammonium tartrate dosemeters and gadolinium oxide (5 % by weight). The choice of low amount of Gd is due to the need of improving neutron sensitivity while not significantly influencing tissue equivalence. A study of the effect of gadolinium presence on tissue equivalence was carried out. The experiments show that the neutron sensitivity is enhanced by more than an order of magnitude even with this small additive content. Monte Carlo simulations on the increment of energy release due to gadolinium presence were carried, and the results were in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Most of the artworks constituting the collection of Renaissance statuary of Abatellis Palace in Palermo (Sicily) show evidence of colour layers and fragments of gold foil that probably once covered the whole marble surface. The restoration of some of these statues has allowed to carry out archaeometric studies about the painting technique and to highlight the original materials and inclusion present on the precious marbles by two famous Italian sculptors of the Renaissance, Francesco Laurana and Antonello Gagini. The measurements have been performed in situ through the integrated use of two non-invasive techniques: visible fluorescence stimulated by ultraviolet light and X-ray fluorescence. The ultraviolet-induced fluorescence analysis has provided additional information on the conservation status of marble surfaces by differentiating the pictorial materials and highlighting the presence of gilding and pigment traces through their characteristic fluorescence response. The observation in ultraviolet light has been used as valuable guide for the identification of the significant points to be analysed by X-ray fluorescence to characterise the original materials. X-ray fluorescence measurements have cast light about their chemical composition and stratigraphical structure. Pictorial layers were identified: vermilion for red layers, blue pigment based on copper for blue layers and pure gold leaf for gilding layers. Principal component analysis of the data was capable of clustering the different painting materials, discriminating through their chemical content. The results represent an important scientific support both to the hypotheses about the original look of the artworks and to the resolution of restoration and conservation questions still open. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on ‘Retrospective Dosimetry’ has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements. [ABSTRACT FROM PUBLISHER]

systematic investigation of the original materials and the degradation phenomena induced by soluble salts on the wall matrix and on the graffiti of the Inquisition jails of Chiaramonte Palace in Palermo (Italy) was carried out. Built in the XIV century, Chiaramonte Palace was used as Inquisition court during the XV–XVI centuries. The ancient graffiti, recently discovered, represent a unique historical witness of the prisoners that lived during that terrible period. In order to study the nature, the amount and the distribution of the salts in the masonry, stone materials sampled at different depth from the wall matrix and saline efflorescences were analysed. Different physical techniques were used, such as X-ray Photoelectron Spectroscopy, X-ray Fluorescence, Laser Induced Breakdown Spectroscopy, X-ray Diffraction and Ionic Chromatography. Results of the chemical and physical characterisation showed that the main cause of the degradation of graffiti and wall paintings was the presence of soluble salts, such as nitrates, chlorides and sulphates. Traces of oxalates, coming from a previous conservation treatment, were also found. The results obtained by the stratigraphical characterisation of soluble salts in the wall matrix can be used to recommend a procedure based on air humidification at high relative humidity values in order to avoid salt crystallisation and to prevent the crumbling process of the graffiti. [ABSTRACT FROM AUTHOR]

Within a more general study on marine sediments in the Gulf of Palermo (Sicily, Italy), the 210Pbex dating method (using a model with constant sedimentation rate) has been applied to one sediment core. The main goal of the research was to study the Pb pollution chronology. Dating of the core has allowed evaluating the time evolution of the gulf lead concentrations. Specific activities of 137Cs have also been measured in the sediment core sections as an independent confirmation of the chronology derived by the 210Pbex method. The time scale has then been used to correlate lead concentrations in core sections to estimated lead emissions in air due to gasoline combustion. A good correlation between the two data series has been obtained. [ABSTRACT FROM AUTHOR]