431 research outputs found
Nota sul De doctrina christiana: un riferimento biblico per l'intelligere e per il proferre
No full textImproved prediction of the number of residue contacts in proteins by recurrent neural networks
No full textKnowing the number of residue contacts in a protein is crucial for deriving constraints useful in modeling protein folding, protein structure, and/or scoring remote homology searches. Here we use an ensemble of bidirectional recurrent neural network architectures and evolutionary information to improve the state-of-the-art in contact prediction using a large corpus of curated data. The ensemble is used to discriminate between two different states of residue contacts, characterized by a contact number higher or lower than the average value of the residue distribution. The ensemble achieves performances ranging from 70.1% to 73.1% depending on the radius adopted to discriminate contacts (6à to 12Ã). These performances represent gains of 15% to 20% over the base line statistical predictors always assigning an aminoacid to the most numerous state, 3% to 7% better than any previous method. Combination of different radius predictors further improves the performance. © Oxford University Press 2001
Solubilization and coordination of the HgCl2 molecule in water, methanol, acetone, and acetonitrile: an X-ray absorption investigation
No full textX-ray absorption spectroscopy (XAS) has been employed to carry out structural characterization of the local environment around mercury after the dissolution of the HgCl2 molecule. A combined EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) data analysis has been performed on the Hg L3-edge absorption spectra recorded on 0.1 M HgCl2 solutions in water, methanol (MeOH), acetone and acetonitrile. The Hg-Cl distance determined by EXAFS (2.29(2)-2.31(2) Å) is always comparable to that found in the HgCl2 crystal (2.31(2) Å), demonstrating that the HgCl2 molecule dissolves in these solvents without dissociating. A small sensitivity of EXAFS to the solvent molecules interacting with HgCl2 has been detected and indicates a high degree of configurational disorder associated with this contribution. XANES data analysis, which is less affected by the disorder, was therefore carried out for the first time on these systems to shed light into the still elusive structural arrangement of the solvent molecules around HgCl2. The obtained results show that, in aqueous and MeOH solutions, the XANES data are compatible with three solvent molecules arranged around the HgCl2 unit to form a trigonal bipyramidal structure. The determination of the three-body Cl-Hg-Cl distribution shows a certain degree of uncertainty around the average 180° bond angle value, suggesting that the HgCl2 molecule probably vibrates in the solution around a linear configuration
Transformations through pseudomorphosis of asbestos minerals in thermally processed asbestos-containing materials investigated through SEM/EDS and micro-Raman spectroscopy: implications for recycling of hazardous wastes
No full textAsbestos-containing materials, extensively used in the past in many European countries, are now considered hazardous wastes of great concern. It has been proved that inertization can be obtained via thermal treatment above 1100 °C. This solution relies upon the scientific evidence that all asbestos minerals at high temperature transform into stable crystalline silicates via a solid state recrystallization process [1]. Asbestos fibres preserve the same external crystal habit although a complete modification of the structure at a molecular scale occurred. This phenomenon is called pseudomorphosis. With increasing the temperature of the thermal treatment above 650-750 °C, the transformation sequence of chrysotile asbestos predicts the crystallization of forsterite (Mg2SiO4) and enstatite (MgSiO3 ) [1]. In a system high in Ca, such as cement-asbestos, crystallization of cement phases such as larnite (Ca2SiO4), ferrite (ideally Ca4Al2Fe2O10), and Al-,Ca-,Mg-rich silicates, such as akermanite (ideally Ca2MgSi2O7) and merwinite (ideally Ca3MgSi2O8), occurs. In this work, analytical and spectroscopic techniques coupled with microscopy allowed for the study of individual residual pseudo-morphosed fibre bundles, in cement-asbestos samples heat treated at 1200 °C. Phases detected were mainly monticellite (CaMgSiO4) or akermanite. They likely formed through the reactions: CaO + MgSiO3 (en) -> CaMgSiO4 (mtc), and CaMgSiO4 (mtc) + CaO + SiO2 -> Ca2MgSiO7 (ake). This suggests that, although transformation reactions occurred largely at the solid state, a substantial mobilisation of Ca and Mg resulted. Such a process is essential for the attainment of the bulk mineralogical composition predicted by the phase diagrams in the system CaO-MgO-SiO2 [2]; however, because of crystallization under non equilibrium conditions, departures from the expected bulk phase composition are still observed. This study contributes to the definition of factors conditioning the recycling of transformed cement-asbestos as secondary raw material [2-3]
Gadolinium-DTPA-enhanced MRI to study renal cancer
No full textTo investigate the role of Gd-DTPA in the MR study of renal cancers, 30 patients affected with primary (28) or recurrent (2) renal cancers were submitted to high-field MRI (1.5 T). T1- and T2-weighted and Gd-DTPA-enhanced T1-weighted sequences were always acquired. Based on qualitative and quantitative criteria (calculation of the signal-to-noise ratio in the tumor mass and of the signal-difference-to-noise ratio between tumor and renal parenchyma), Gd-DTPA influence was studied on the following variables: signal intensity and tumor demonstration, detectability of morphostructural features of tumor tissue and staging accuracy. As for the latter variable, MR results were compared with the results of anatomical and surgical staging (28 cases). Relative to unenhanced T1- and T2-weighted sequences, on Gd-DTPA-enhanced sequences 80% of the lesions were markedly hypointense relative to renal parenchyma and they were better demonstrated in 93% of cases. The S/N and the SD/N ratios were higher on Gd-DTPA-enhanced than on unenhanced images. After Gd-DTPA administration, the intratumoral necrotic areas, the walls and the septations of the cystic masses and the boundaries between tumors and renal parenchyma were better demonstrated. Staging accuracy was the same (90%) on both Gd-DTPA-enhanced T1-weighted and unenhanced images. Therefore, Gd-DTPA, although failing to increase staging accuracy, improves tumor depiction and demonstrates the morphostructural features of the mass. Since Gd-DTPA caused no side-effects, Gd-DTPA-enhanced T1-weighted sequences can replace T2-weighted sequences, whose acquisition time is definitely longer
A versatile network of IoT sensors for the environmental parameters monitoring of co-working laboratories
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Une famille de l'aristocratie napolitaine sous les souverains angevins : les Sanseverino (1270-1420)
No full textSylvie Pollastri, Une famille de l'aristocratie napolitaine sous les souverains angevins : les Sanseverino (1270-1420), p. 237-260.
L'histoire de la famille Sanseverino est marquée par le passage, de 1309 à 1418, d'une lignée comtale de Lucanie à un groupe dynastique ayant une emprise sur une province entière. Pour cela, elle a dû jouer des lois strictes de la transmission des fiefs aux premiers nés, de la mise à disposition de biens féodaux pour les dots et des risques constants de dévolution. Un jeu d'alliances matrimoniales les placent comme première famille aristocratique du royaume et de la province de Basilicate. Y est associé tout un travail d'acquisitions territoriales, de concessions de la puissance publique et de titres ecclésiastiques. Les divisions patrimoniales créent autant de rameaux nécessaires à la gestion directe de chaque noyau. Mais les comtes restent liés entre eux autour du cognomen, de la dépendance des cadets, du faire la guerre ensemble et de mariages croisés.Pollastri Sylvie. Une famille de l'aristocratie napolitaine sous les souverains angevins : les Sanseverino (1270-1420). In: Mélanges de l'École française de Rome. Moyen-Age, tome 103, n°1. 1991. pp. 237-260
Prediction of Coordination Number and Relative Solvent Accessibility in Proteins
No full textKnowing the coordination number and relative solvent accessibility of all the residues in a protein is crucial for deriving constraints useful in modeling protein folding, protein structure, and in scoring remote homology searches. We develo
Surface texture measurements of gear tooth
No full textThis work presents a study of the surface texture of gear teeth with different surface finish. Surface data have been analyzed by means of traditional roughness parameters and by the harmonic decomposition with FT transform. A method for selecting the significant frequencies of the roughness profile is presented. A comparison of results on gear teeth made by hobbing, grinding and lapping techniques is shown to point out the main effects of each texture finishing on the harmonic analysis
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