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Abstract: Feature detection in biomedical signals is crucial for deepening our knowledge about the involved physiological processes. To achieve this aim, many analytic approaches can be applied but only few are able to deal with signals whose time dependent features provide useful clinical information. Among the biomedical signals, the electroretinogram (ERG), that records the retinal response to a light flash, can improve our comprehension of the complex photoreceptoral activities. The present study is focused on the analysis of the early response of the photoreceptoral human system, known as a-wave ERG-component. This wave reflects the functional integrity of the photoreceptors, rods and cones, whose activation dynamics are not yet completely understood. Moreover, since in incipient photoreceptoral pathologies eventual anomalies in a-wave are not always detectable with a “naked eye” analysis of the traces, the possibility to discriminate pathologic from healthy traces, by means of appropriate analytical techniques, could help in clinical diagnosis. In the present paper, we discuss and compare the efficiency of various techniques of signal processing, such as Fourier analysis (FA), Principal Component Analysis (PCA), Wavelet Analysis (WA) in recognising pathological traces from the healthy ones. The investigated retinal pathologies are Achromatopsia, a cone disease and Congenital Stationary Night Blindness, affecting the photoreceptoral signal transmission. Our findings prove that both PCA and FA of conventional ERGs, don't add clinical information useful for the diagnosis of ocular pathologies, whereas the use of a more sophisticated analysis, based on the wavelet transform, provides a powerful tool for routine clinical examinations of patients. [Copyright &y& Elsevier]

Abstract: Thermoluminescence dosimetry has been used to measure air kerma in 29 sites in Sicily. Four three month measurement campaigns have been carried out in order to assess seasonal variations. Average annual values between 20 and 90nGyh−1, after cosmic background subtraction, are reported. Average annual values are strongly dependent on site lithology, and we find that winter data are generally the highest, while spring and autumn rates are generally the lowest with very similar trends in any site. Summer values generally lay in between. Largest seasonal variations are found in sites along the southern coast of the island, probably because of stronger action of winds affecting radon, along with its progeny, concentrations at ground level. [Copyright &y& Elsevier]

Abstract: We investigated the ESR response of new materials, alanine and ammonium tartrate to which gadolinium was added. The addition of gadolinium enhances sensitivity for -photons because of its high atomic number and an enhancement of sensitivity for thermal neutrons because of its high thermal neutron cross section and high linear energy transfer (LET) secondary particles produced after the reaction with neutrons. In particular, in this paper we analyzed the microwave power saturation properties of dosimeters of alanine and ammonium tartrate with or without gadolinium exposed to different LET beams. The power saturation trends of dosimeters exposed to photons and to thermal neutrons are different. For ammonium tartrate dosimeters the gadolinium addition intensifies significantly these differences and therefore, it improves the ammonium tartrate''s ability to discriminate the radiation LET . [Copyright &y& Elsevier]

Abstract: ESR response to γ-irradiation (1–50Gy) of blends containing alanine and either B(OH)3 or Gd2O3 is reported. The sensitivity of the alanine—B(OH)3 blend is comparable to the sensitivity of pure alanine, although its lowest detectable dose, LDD, is smaller (∼1.3Gy) than that of pure alanine (∼2.9Gy). Alanine with Gd2O3 is about two times more sensitive than pure alanine, and its LDD is 0.8Gy. The better sensitivity and LDD are probably due to the high atomic number of gadolinium, which enhances the interaction probability with photons and, consequently, the radical yield. This study suggests that other high-Z atoms may be useful for increasing the sensitivity of the response of alanine to γ-radiation. [Copyright &y& Elsevier]

Abstract: This work presents experimental results regarding a new ammonium tartrate blend for ESR dosimetry, with a higher sensitivity and a lower lowest detectable dose (LDD) to -rays than the recently used pure ammonium tartrate. The blend composed by ammonium tartrate and gadolinium-oxide shows a greater sensitivity (2 times) and a smaller LDD than ammonium tartrate. The increased sensitivity was mainly attributed to the great atomic number of gadolinium, that increases the effective atomic number of the blend; the interaction probability with photons and consequently the radical yield is therefore enhanced. Moreover ammonium tartrate with has a linear dose response in the investigated dose range (1–50Gy). We find this blend suitable for use in ESR dosimetry. [Copyright &y& Elsevier]

Abstract: Sicily, the largest Mediterranean island (with an extension of about ), exhibits a very wide variety of lithologies, ranging from sedimentary to metamorphic and volcanic rocks. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied to air kerma values measured by thermoluminescent dosimetry in several sites and to data of radionuclide concentrations, geochemical and mineralogical features of rocks and soils sampled in 29 sites of Sicily to point out similarities among different lithologies. The study was devoted to find multiple correlations and allow a better classification of Sicilian lithotypes. Samples of rocks and soils have been analyzed by X-ray fluorescence (XRF), X-ray diffractometry (XRD), and gamma-ray spectrometry. Major element concentrations, mineralogical data, along with specific activities of 40K, 238U, and 232Th natural radionuclides, have been determined in several samples. Geochemical, mineralogical and petrographic features are in good agreement with radiometric data. A survey was also performed to measure air kerma in outdoor environment using thermoluminescent dosimeters. The measured values were compared with the predicted levels computed from the radioisotope concentrations present in rock and soil samples. Moreover, collected data can be used to evaluate the health impact of the natural radioactivity on the population. [Copyright &y& Elsevier]

HPGe gamma spectrometry, thermoluminescence dosimetry, X-ray diffractometry and fluorescence techniques have been used to analyze the natural radionuclides content of soil and rock samples, air kerma and geochemical features on the island of Stromboli, belonging to the Aeolian Islands, in the Mediterranean Sea. The 214Bi, 238Ac, and 40K contents obtained are in agreement with the magmatic evolution of the rock formation, as shown by the correlations between radionuclide and chemical elements abundacies, depending on the various magmatic differentiation mechanisms. Correlations between radiometric, lithological and geochemical data have been assessed in order to obtain some hints on the geochronology of the magmatic products. [Copyright &y& Elsevier]

Abstract: The thermoluminescence response of a watch commercial glass was studied after irradiation with photons and electrons, in the range 1–20 Gy, of interest in accidental dosimetry; a linear response was obtained with both beams. This result, together with the satisfactory time stability of the thermoluminescence signal, indicates this glass as a potential material for retrospective dosimetry applications. [Copyright &y& Elsevier]

Abstract Purpose The aim of this work is the dosimetric verification of stereotactic head treatments performed with Helical Tomotherapy [1] using an anthropomorphic phantom, the Rando Head Alderson, combined with alanine [2] dosimeters and EBT3 gafchromic films [3]. Methods A CT scan of Rando Head Phantom was used to simulate five different clinical situations regarding "tumor" dimension, position and proximity relations with Organs at Risk (OAR). All five treatment plans were computed using 1 cm beam width, pitch values lower than 0.215 and modulation factor between 1.6 and 2.5. In all cases, the dose constraints required for OAR have been met. During treatment delivery, the alanine dosimeters were placed in the phantom housings to perform dose-specific measurements for either the PTV and OAR, and gafchromic films were inserted between contiguous slices of the phantom to achieve bidimensional dose distributions on the transverse plane. Results Dose distributions measured by gafchromic films were compared to those calculated using the 3% – 3 mm criterion for the gamma function using the Tomotherapy DQA module. Also the results of point measurements made with alanine agree with the dose values calculated by TPS within the experimental uncertainties. Conclusions The data show an excellent agreement between calculated and measured dose not only for PTV but also for the OAR, receiving significantly lower doses. [ABSTRACT FROM AUTHOR]

In the early period, even though professional photographers worked with similar techniques and products, their artistic and commercial aims determined different choices and led them to follow different, often personal, recipes. For this reason, identification of the techniques through date and name of the photographer or through some visual features like colour, tonality and surface of the image layer, often needs further investigation to be proved. Chemical characterization, carried out in a non or micro destructive way, can be crucial to provide useful information about the original composition, degradation process, realization technique, in obtaining an indirect dating of the photograph and/or to choose the most correct conservation treatment. In our case, x-ray fluorescence (XRF) analysis was used to confirm the chemical composition of eleven historical photographs dated between the end of the 19th century and the beginning of the 20th, shot in Palermo (Sicily) by a renowned photographer of the time, and pasted on their original cardboards. The elemental identification, obtained with a non destructive approach, provided important information to distinguish among different photographic techniques in terms of distribution and characterization of chemical elements markers in the photographic surface. [ABSTRACT FROM AUTHOR]

Abstract: Most biomedical signals are non-stationary. The knowledge of their frequency content and temporal distribution is then useful in a clinical context. The wavelet analysis is appropriate to achieve this task. The present paper uses this method to reveal hidden characteristics and anomalies of the human a-wave, an important component of the electroretinogram since it is a measure of the functional integrity of the photoreceptors. We here analyse the time–frequency features of the a-wave both in normal subjects and in patients affected by Achromatopsia, a pathology disturbing the functionality of the cones. The results indicate the presence of two or three stable frequencies that, in the pathological case, shift toward lower values and change their times of occurrence. The present findings are a first step toward a deeper understanding of the features of the a-wave and possible applications to diagnostic procedures in order to recognise incipient photoreceptoral pathologies. [Copyright &y& Elsevier]

Abstract: The electron paramagnetic resonance (EPR) spectroscopy is widely applied for retrospective dosimetric purposes by means of quantitative detection of radicals in tooth enamel and bone samples. In this work we report a study by cw and pulsed EPR on two samples of human tooth enamel respectively irradiated by UV (254 nm) and γ-exposed. The continuous wave (cw) EPR spectra have shown the usual presence in both samples of two types of radicals, with axial and orthorombic g tensors. We have obtained the electron spin echo detected EPR (ED-EPR) spectra at 80 K of the two samples, and we have shown that they are suitable to mark the difference between the effects produced by the different irradiations. At low temperature the contribution to the ED-EPR spectrum of the mobile radical with the axial g tensor is still present in the UV irradiated sample, but not in the γ-irradiated one, where its dynamics is too slow to average the g tensor. We have moreover studied the two-pulse electron spin echo decay on varying the microwave power, a well established method for measuring the Instantaneous Diffusion. We have found that the spectral diffusion parameter is almost the same for both radiation types, whereas the Instantaneous Diffusion is significantly larger for γ-exposed samples than for UV irradiated ones. This difference is due to a higher local microscopic concentration of free radicals for samples irradiated with γ photons. [Copyright &y& Elsevier]

Abstract: In this paper we have analyzed the electron spin resonance (ESR) signal of watch glasses irradiated with ≈60MeV proton beams in the dose range between 1 and 105Gy. The composition of samples expressed in oxides weight percentages has been obtained carrying out X-ray fluorescence spectrometry (XRF) measurements. The ESR signal has been studied in terms of its dependence on microwave power and modulation field in order to choose the optimal recording parameters. The dependence of the radioinduced signal on the exposure dose has been investigated. A numerical procedure aimed at improving the sensitivity in the low dose range has been developed. [ABSTRACT FROM AUTHOR]

Abstract: A petrographic and radiometric study, along with statistical multivariate analysis of volcanic products of the island of Lipari (Aeolian islands, Italy) was carried out. The volcanological history of Lipari was reconstructed defining two stages (pre- and post-erosive stages) further on subdivided in four volcanic phases, each of which characterized by products with a particular chemical composition and separated by stratigraphic unconformities. The correlations between petrographic features, determined by X-ray fluorescence, and volcanological history of the island highlight a gradual differentiation with younger rocks showing a more acid chemical composition than the older ones. Radiometric features, and in particular the content of primordial radionuclides 238U, 232Th and 40K, have been measured through gamma-ray spectrometry with hyper-pure germanium detector. The different volcanic lithologies, such as basalts, andesites and rhyolites, have been characterized by petrographic diagrams. The calculated dose rate has also been used as an additional classification parameter. Older products show low alkali content than the younger ones. This is related with the increasing of incompatible elements, such as uranium and thorium, in the younger products. Principal components and hierarchical clustering statistical analyses have provided additional information on sample differentiation and similarities. [Copyright &y& Elsevier]

Abstract: We analyze the spatial distributions of two groups of benthic foraminifera (), along Sicilian coast, and their correlation with six different heavy metals, responsible for the pollution. Samples were collected inside the Gulf of Palermo, which has a high level of pollution due to heavy metals, and along the coast of Lampedusa island (Sicily Channel, Southern Mediterranean), which is characterized by unpolluted sea waters. Because of the environmental pollution we find: (i) an anticorrelated spatial behaviour between the two groups of benthic foraminifera analyzed; (ii) an anticorrelated (correlated) spatial behaviour between the first (second) group of benthic foraminifera with metal concentrations; (iii) an almost uncorrelated spatial behaviour between low concentrations of metals and the first group of foraminifera in clean sea water sites. We introduce a two-species model based on the generalized Lotka–Volterra equations in the presence of a multiplicative noise, which models the interaction between species and environmental pollution due to the presence in top-soft sediments of heavy metals. The interaction coefficients between the two species are kept constant with values in the coexistence regime. Using proper values for the initial conditions and the model parameters, we find for the two species a theoretical spatial distribution behaviour in a good agreement with the data obtained from the 63 sites analyzed in our study. [Copyright &y& Elsevier]

Abstract: Electron spin resonance solid state dosimetry with alanine and ammonium tartrate pellets is a valuable tool in both medical and industrial applications when dealing with photon and charged particle beams. Its use in neutron beams is limited by the low nuclear cross section values of atoms in the pellets. Addition of boron (10B) or gadolinium , known to have high neutron capture cross sections, has been proposed to improve neutron sensitivity. In this paper we present the results of an experimental study concerning neutron sensitivity vs. gadolinium concentration in dosimeter mixtures, with the aim of optimizing mixture composition and maximizing the electron spin resolution (ESR) signal. For gadolinium concentrations up to about 25%, the dosimeter sensitivity increases with concentration. A saturation value is reached afterwards because of the smaller presence of the main ESR sensible compounds (i.e. alanine or ammonium tartrate). Monte Carlo techniques have been applied and comparisons between computational and experimental results have been carried out. [Copyright &y& Elsevier]

Abstract: Monte Carlo numerical calculations of the response of alanine and ammonium tartrate ESR (electron spin resonance) dosimeters exposed to neutron fields with different energy spectra are reported. Results have been obtained for various gadolinium concentrations inside the dosimeters. Furthermore, in order to simulate the in-phantom response we have carried out calculations by varying the depth of the dosimeter. We have found that a large enhancement is obtained for thermal neutrons, because of the very high capture cross section of gadolinium to thermal neutrons. A good enhancement was obtained for epithermal neutrons, whereas the sensitivity improvement in the case of fast neutron irradiation is poor. Furthermore, the simulations carried out by varying the depth suggests that an appreciable sensitivity to thermal and epithermal neutrons could be observed for in-phantom measurements in the 2–3cm depth range. These results can provide useful insight for future experiments with epithermal neutron beams (such as those used in neutron capture therapy) and for future applications in neutron capture therapy dosimetry. [Copyright &y& Elsevier]

Abstract: In this work we report a case study of the ESR response of watch glasses exposed to 6 MV photons and to 10 MeV electrons. The choice of watch glasses is justified by the fact that watch glasses are very close to the exposed individual. For both types of radiation beams, the absorbed doses belong to the range between 1 and 20 Gy. The samples have been irradiated in water-equivalent plastic phantom with a linear accelerator used for radiotherapy. After exposure watch glass samples have been cut in small strip-shaped pieces with suitable size to be put into the quartz tube for ESR measurements. The signal induced by radiation (RIS) lies in the g ∼ 2 region and must be discriminated from the background signal (BS). An analysis of both signals has been carried out in order to isolate the signal sensitive to ionizing radiation from the background one. We have studied the ESR response of irradiated samples as a function of the absorbed dose. Furthermore estimates of the detection limits have been achieved. [Copyright &y& Elsevier]

Abstract: This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum München. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers. [Copyright &y& Elsevier]

Abstract: The paper discusses the results of an investigation aimed to use the ESR spectroscopy as a quantitative procedure to estimate the original dose in irradiated chicken. The time stability of the ESR signal was at first carried out, to obtain a correction factor to be applied to the dose estimated with the added dose method. Our results show that this procedure gives an estimation of the original dose within ±25%. [Copyright &y& Elsevier]

Abstract: Thermoluminescence (TL) dosimetry is one of the physical methods used for the identification of irradiated food, suitable for foods from which silicate minerals can be extracted. The aims of the present work were to apply the TL analysis for a qualitative identification of irradiated oregano, and to set up a quantitative procedure to estimate the original treatment dose on the sample. The experimental results show that the TL analysis allows to distinguish irradiated oregano even seven months after the treatment. The additive dose procedure gives a rough estimation of the treatment dose, but can be helpful when the TL ratio method is unsatisfactory. [Copyright &y& Elsevier]

Abstract: Ionizing radiation is widely used as treatment technique for food preservation. It involves among others reduction of microbial contamination, disinfestations, sprout inhibition and extension of shelf life of food. However, the commercialization of irradiated food requires the availability of reliable methods to identify irradiated foodstuffs. In this paper, we present results on the application to irradiated chicken of this method, based on the detection, in muscle and skin samples, of the peaks of ions 98 Da and 112 Da, in a ratio approximately 4:1, typical of radiation induced 2-dodecylcyclobutanones (2-DCB). Aim of the work was also to study the time stability of the measured parameters in samples irradiated at 3 and 5kGy, and to verify the efficacy of the treatment from a microbiological point of view. Our results show that, one month after irradiation at 3kGy, the method is suitable using the skin but not the muscle, while the measured parameters are detectable in both samples irradiated at 5kGy. The microbial population was substantially reduced even at 3kGy. [Copyright &y& Elsevier]