Search results for "Beni culturali"

Irreversible gelation of thermally unfolded proteins:structural and mechanical properties of lysozyme aggregates

2010

The formation of protein aggregates is important in many fields of life science and technology. The morphological and mechanical properties of protein solutions depend upon the molecular conformation and thermodynamic and environmental conditions. Non-native or unfolded proteins may be kinetically trapped into irreversible aggregates and undergo precipitation or gelation. Here, we study the thermal aggregation of lysozyme in neutral solutions. We characterise the irreversible unfolding of lysozyme by differential scanning calorimetry. The structural properties of aggregates and their mechanisms of formation with the eventual gelation are studied at high temperature by spectroscopic, rheolog…

On the molecular structure of human neuroserpin polymers

2012

The polymerization of serpins is at the root of a large class of diseases; the molecular structure of serpin polymers has been recently debated. In this work, we study the polymerization kinetics of human neuroserpin by Fourier Transform Infra Red spectroscopy and by time-lapse Size Exclusion Chromatography. First, we show that two distinct neuroserpin polymers, formed at 45 and 85°C, display the same isosbestic points in the Amide I' band, and therefore share common secondary structure features. We also find a concentration independent polymerization rate at 45°C suggesting that the polymerization rate-limiting step is the formation of an activated monomeric species. The polymer structures…

Biophysical investigation on therapeutic proteins (Chaperonins, Hsp60 and CCT/TRiC) involved in human diseases

Molecular chaperones are indispensable cellular components that assist folding and assembly of newly synthesized proteins, translocation of proteins across membranes, as well as refolding and degrading of misfolded and aggregated proteins. In the last few years, innovative therapeutic strategies targeting stability and functionality of chaperones have received great attention, particularly in the field of neurodegenerative diseases. Moreover, the growing number of diseases found linked to chaperone mutations, testifies to the importance of their role in the cellular protein-quality control mechanism. The investigation of the biophysical interactions between chaperones and specific proteins …

Kinetic energy and radial momentum distribution of hydrogen and oxygen atoms of water confined in silica hydrogel in the temperature interval 170–325…

2019

Water is an ubiquitous liquid and it is necessary for life;. Studies on water are therefore of obvious scientific and .... technological relevance. In view of its peculiar physicalproperties (the so-called water anomalies, particularly relevant at low temperatures [1]), studies on water structureand dynamics in ample temperature intervals, covering also the supercooling region, have attracted much interest in recent years. In particular, studies focused on the supercooled phase are important in order to test theories and hypotheses[2,3], including the liquid-liquid phase transition hypothesis [4-6] and the related fragile-to-strong crossover observed inwater confined in silica matrices and …

Evolutionary dynamics of imatinib-treated leukemic cells by stochastic approach

2008

The evolutionary dynamics of a system of cancerous cells in a model of chronic myeloid leukemia (CML) is investigated by a statistical approach. Cancer progression is explored by applying a Monte Carlo method to simulate the stochastic behavior of cell reproduction and death in a population of blood cells which can experience genetic mutations. In CML front line therapy is represented by the tyrosine kinase inhibitor imatinib which strongly affects the reproduction of leukemic cells only. In this work, we analyze the effects of a targeted therapy on the evolutionary dynamics of normal, first-mutant and cancerous cell populations. Several scenarios of the evolutionary dynamics of imatinib-tr…

MONTE CARLO SIMULATIONS OF THE RESPONSE OF ESR DOSIMETERS TO NEUTRON BEAMS

2009

Electron Spin Resonance (ESR) spectroscopy is extensively used in gamma photon dosimetry. It relies on the detection of the signal from free radicals (paramagnetic species) produced after sample irradiation. Organic materials, such as alanine and ammonium tartrate, are widely used for dosimeter preparation, thanks to the good photon sensitivity and tissue equivalence of such compounds. However, the low neutron cross section of their nuclei does not make them suitable for neutron dosimetry. Thanks to its very high neutron capture cross section and to the high Linear Energy Transfer of released particles, even small additions of gadolinium will yield large sensitivity enhancements of the dosi…

Optimization of quasi-hemispherical CdZnTe detectors by means of first principles simulation

2023

AbstractIn this paper we present the development of quasi-hemispherical gamma-ray detectors based on CdZnTe. Among the possible single-polarity electrode configurations, such as coplanar, pixelated, or virtual Frisch-grid geometries, quasi-hemispherical detectors are the most cost-effective alternative with comparable raw energy resolution in the high and low energy range. The optimal configuration of the sensor in terms of dimension of the crystals and electrode specifications has been first determined by simulations, and successively validated with experimental measures. Spectra from different sources have been acquired to evaluate the detectors performances. Three types of detectors with…

Determination of selected phthalates by gas chromatography–mass spectrometry in mural paintings from Palermo (Italy)

2013

Abstract Phthalate esters for decades, and probably even now, were used as softeners in water-based paintings. In general, these compounds are dangerous owing to their carcinogenicity and reproductive effects. Phthalates are not chemically but only physically bound to the matrices, hence, they may be leached into the environment and are ubiquitously found in environmental matrices. Considering that, construction is one of most important fields in Europe, and probably worldwide, with respect to its economic, technological and environmental impact. In the present work the phthalate esters content of several mural paintings was evaluated by gas chromatography–mass spectrometry (GC-MS). Because…

Improvement of neutron sensitivity for lithium formate ESR dosimeters: A Monte Carlo analysis

2023

This work presents the computational analysis of the sensitivity improvements that could be achieved in lithium formate monohydrate (LFM) electron paramagnetic resonance (EPR) dosemeters exposed to neutron beams. Monte Carlo (MC) simulations were performed on LFM pellets exposed to neutron beams with different energy spectra at various depths inside a water phantom. Various computations were carried out by considering different enrichments of 6Li inside the LFM matrix as well as addition of different amounts of gadolinium oxide inside the pellet blend. The energy released per unit mass was calculated with the aim of redicting the increase in dose achievable by the addition of sensitizers in…

Neolithic ceramic findings from western Sicily. Chemical – physical and mineralogical characterization

2001

This paper presents the results of a study that is part of a wider research program regarding the knowledge of the initial living phases of Sicilian agricultural and pastoral societies.Three ceramic samples attributed to the medium initial Neolithic (NEO1 and NEO2) and to the first neolithic (NEO3), recovered in two different archaeological sites of the western Sicily, have been analysed. Chemical, mineralogical and spectroscopic data point out a similarity between NEO1 and NEO3 samples; compositional and morphological differences instead have been observed in the NEO2 sample. The firing temperatures of the samples have been estimated by Mössbauer spectroscopy; they are lower than 500°C for…