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The corrosion of chromia-forming alloys by molten glass is an issue encountered in industrial processes such as glass fiber production or nuclear waste vitrification. A model of the corrosion of such alloys in molten glass media is developed in this work. This simple model predicts the corrosion state of the alloy (passive of active) and the evolution of the Cr2O3 layer thickness with a low number of input parameters. Furthermore, the model allows to explain the depassivation of the alloy by identifying the conditions involving a lack of oxygen supply in the liquid towards the oxide.

Effect of Total Apple Polyphenols Extract as Inhibitors of Amyloid Protein Aggregation By: Guarrasi, Valeria; Rappa, Cinzia Giacoma; Costa, Maria Assunta; et al. JOURNAL OF CLINICAL GASTROENTEROLOGY Volume: 52 Supplement: 1 Pages: S94-S94 Published: NOV-DEC 2018

Chaperonins play various physiological roles and can also be pathogenic. Elucidation of their structure, e.g., oligomeric status and post-translational modifications (PTM), is necessary to understand their functions and mechanisms of action in health and disease. Group I chaperonins form tetradecamers with two stacked heptameric rings. The tetradecamer is considered the typical functional complex for folding of client polypeptides. However, other forms such as the monomer and oligomers with smaller number of subunits than the classical tetradecamer, also occur in cells. The properties and functions of the monomer and oligomers, and their roles in chaperonin-associated diseases are still incompletely understood. Chaperonin I in eukaryotes occurs in various locations, not just the mitochondrion, which is its canonical place of residence and function. Eukaryotic Chaperonin I, namely Hsp60 (designated HSP60 or HSPD1 in humans) has, indeed, been found in the cytosol; the plasma-cell membrane; on the outer surface of cells; in the intercellular space; in biological liquids such as lymph, blood, and cerebrospinal fluid; and in secretions, for instance saliva and urine. Hsp60 has also been found in cell-derived vesicles such as exosomes. The functions of Hsp60 in all these non-canonical locales are still poorly characterized and one of the questions not yet answered is in what form, i.e., monomer or oligomer, is the chaperonin present in these non-canonical locations. In view of the steady increase in interest on chaperonopathies over the last several years, we have studied human HSP60 to determine its role in various diseases, its locations in cells and tissues and migrations in the body, and its post-translational modifications that might have an impact on its location and function. We also carried out experiments to characterize the oligomeric status of extramitochondrial of HSP60 in solution. Here, we provide an overview of our results, focusing on the oligomeric equilibrium and stability of the various forms of HSP60 in comparison with GroEL. We also discuss post-translational modifications associated with anti-cancer drugs to indicate the potential of Hsp60 in Medicine, as a biomarker and etiopathogenic factor.

In 2013, the Italian Society of Nephrology joined forces with Nephrocare-Italy to create a clinical research cohort of patients on file in the data-rich clinical management system (EUCLID) of this organization for the performance of observational studies in the hemodialysis (HD) population. To see whether patients in EUCLID are representative of the HD population in Italy, we set out to compare the whole EUCLID population with patients included in the regional HD registries in Emilia-Romagna (Northern Italy) and in Calabria (Southern Italy), the sole regions in Italy which have systematically collected an enlarged clinical data set allowing comparison with the data-rich EUCLID system. An analysis of prevalent and incident patients in 2010 and 2011 showed that EUCLID patients had a lower prevalence of coronary heart disease, peripheral vascular disease, heart failure, valvular heart disease, liver disease, peptic ulcer and other comorbidities and risk factors and a higher fractional urea clearance (Kt/V) than those in the Emilia Romagna and Calabria registries. Accordingly, survival analysis showed a lower mortality risk in the EUCLID 2010 and 2011 cohorts than in the combined two regional registries in the corresponding years: for 2010, hazard ratio (HR) EUCLID vs. Regional registries: 0.80 [95% confidence interval: 0.71–0.90]; for 2011, HR: 0.76 [0.65–0.90]. However, this difference was nullified by statistical adjustment for the difference in comorbidities and risk factors, indicating that the longer survival in the EUCLID database was attributable to the lower risk profile of patients included in that database. This preliminary analysis sets the stage for future observational studies and indicates that appropriate adjustment for difference in comorbidities and risk factors is needed to generalize to the Italian HD population analyses based on the data-rich EUCLID database.

Chromia forming Alloy 718 and AD730™ have been submitted to isothermal long-term air exposure up to 10 000 h at 700 °C. The resulting very low specific mass gain led to consider two alternatives to determine the oxidation kinetics. Measurements of the external layer thickness and of the intergranular oxide amount were carried out on SEM micrographs evidencing the intergranular oxidation contribute around 30% to the total specific mass change. AD730™ with a thicker external scale and a higher amount of intergranular oxide showed a twofold faster oxidation rate than Alloy718. The results demonstrated the need of even longer tests.

The short-term oxidation behaviour of RA 602CA, Inconel 693, Manaurite 40XO and Sumitomo 696, which are four alloys recommended for hydrocarbon processing, was studied both in air and in Ar–H2O to determine the conditions of pre-oxidation treatments. Regardless of the considered material, the oxidation rate at 950 °C was systematically higher in Ar–H2O than in dry air. Surface examination of the Al-containing alloys indicated that they were not uniformly oxidized all over the surface. All Al-containing alloys (from 1.6 to 3.2% wt) formed an external protective alumina scale and behaved as alumina-forming alloys in dry air at 950 °C. In contrast, these alloys developed a rate-controlling chromia scale and severe internal oxidation in a H2O-containing atmosphere. Compared with their oxidation behaviour in air + H2O, the phenomenon was significantly enhanced in the atmosphere that coupled water vapour with a low oxygen pressure. Consequently, the Al-containing alloys should not be pre-oxidized in a water vapour atmosphere prior to long exposure to a corrosive atmosphere. In contrast, the chromia-forming Al-free 696 alloy exhibited identical oxidation behaviour in both atmospheres, demonstrating that the degradation of this alloy was not significantly affected by water vapour.

The possibility to tune the semiconducting properties of chromia scales thermally grown on pure chromium as a function of temperature and oxygen partial pressure p (O 2 ) has been demonstrated in the present paper. While at 800 °C and a p (O 2 ) of 10 −14 atm, a single n -chromia is observed, at 900 °C and a p (O 2 ) of 10 −12 atm, a duplex n - and p -chromia is obtained. Between these two situations, a stoichiometric chromia exhibiting insulating properties could be identified at 850 °C and a p (O 2 ) of 10 −13 atm. In every case, the morphology of the oxide scale is duplex and seems to depend only on the growth direction: equiaxis grains for an inward (anionic) growth and columnar grains for an outward (cationic) growth. The nature of point defects, linked to the n or p semiconducting character, governs the oxide growth but surprisingly, does not seem to have any influence on the oxide scale morphology. Finally, the control of the growth of an insulating stoichiometric chromia layer should permit to optimize its protective character.

The corrosion behaviour and the oxidation mechanism of a ferritic stainless steel, K41X (AISI 441), were evaluated at 800 °C in water vapour hydrogen enriched atmosphere. Mirror polished samples were compared to as-rolled K41X material. Two different oxidation behaviours were observed depending on the surface finishing: a protective double (Cr,Mn) 3 O 4 /Cr 2 O 3 scale formed on the polished samples whereas external Fe 3 O 4 and (Cr,Fe) 2 O 3 oxides grew on the raw steel. Moreover, isotopic marker experiments combined with SIMS analyses revealed different growth mechanisms. The influence of surface finishing on the corrosion products and growth mechanisms was apprehended by means of X-ray photoelectron spectroscopy (XPS) and residual stress analyses using XRD at the sample surfaces before ageing.

High temperatures solid-liquid equilibria in the Cr-Nb-Si system are poorly known in the Si-rich area (>20% at Si). In this study, twenty-two as-cast samples were prepared and fully characterized using X-ray diffraction, scanning electron microscopy and quantitative energy dispersive spectrometry. Obtained results lead us to propose a new schematic layout of the liquidus projection of this system.

The oxidation behaviour of Ti3(Ni,Cr)3CrSi6 and Ti4Ni4Si7 was studied in air both at 1000 and 1100 °C. The formation of the oxidation products and the phase transformation were characterized by in situ X-ray diffraction and SEM-FEG post-mortem observations. The crystal structure of Ti3(Ni,Cr)3CrSi6 was also determined using powder X-ray diffraction and Rietveld refinement in order to describe this phase as a pseudolamellar structure comparable to the one of Ti4Ni4Si7. Results evidenced that diffusion in solid state governs the oxidation rate of these silicides. Ti4Ni4Si7 oxidation rate was assessed as being one order of magnitude lower than the one of Ti3(Ni,Cr)3CrSi6, while this latter readily transformed into Ti4Ni4Si7 during the first time of oxidation. The understanding of this particular behaviour in which the oxidation rate of Ti3(Ni,Cr)3CrSi6 was not affected by the phase transformation implied to consider the crystallographic lamellar features of these compounds that play a major role in the diffusion of the most oxidizable elements.

To provide protection against corrosion at high temperatures, silicide diffusion coatings were developed for the V-4Cr-4Ti alloy, which can be used as the fuel cladding in next-generation sodium-cooled fast breeder reactors. The multilayered coatings were prepared by halide-activated pack cementation using MgF 2 as the transport agent and pure silicon (high activity) as the master alloy. Coated pure vanadium and coated V-4Cr-4Ti alloy were studied and compared as substrates. In both cases, the growth of the silicide layers (V 3 Si, V 5 Si 3 , V 6 Si 5 and VSi 2 ) was controlled exclusively by solid-state diffusion, and the growth kinetics followed a parabolic law. Wagner's analysis was adopted to calculate the integrated diffusion coefficients for all silicides. The estimated values of the integrated diffusion coefficients range from approximately 10 −9 to 10 −13 cm 2 s −1 . Then, a diffusion-based numerical approach was used to evaluate the growth and consumption of the layers when the coated substrates were exposed at critical temperatures. The estimated lifetimes of the upper VSi 2 layer were 400 h and 280 h for pure vanadium and the V-4Cr-4Ti alloy, respectively. The result from the numeric simulation was in good agreement with the layer thicknesses measured after aging the coated samples at 1150 °C under vacuum.

In this work a re-investigation of the solubility limits of the (Nb), Nb3Al, Nb2Al and the Nb-rich side of the NbAl3 phases on the Nb-Al system is presented. Alloys in the binary fields ((Nb)+Nb3Al, Nb3Al+Nb2Al and Nb2Al+NbAl3) were arc-melted, and then equilibrated at 1000, 1200 and 1400 oC. The phases were confirmed via X-ray powder diffractometry, and their compositions were determined via EPMA measurements. The results showed agreement with the literature concerning the solubility limits of (Nb), Nb3Al and NbAl3 phases, while important differences in the values were found for the Nb2Al phase. In addition, the lattice parameters of the Nb2Al phase were determined via Rietveld refinement. This new set of more accurate experimental information indicates that a thermodynamic reassessment is necessary to precisely describe this system.

Alzheimer's disease is a chronic neurodegenerative disease characterized by the accumulation of pathological aggregates of amyloid beta peptide. Many efforts have been focused on understanding peptide aggregation pathways and on identification of molecules able to inhibit aggregation in order to find an effective therapy. As a result, interest in neuroprotective proteins, such as molecular chaperones, has increased as their normal function is to assist in protein folding or to facilitate the disaggregation and/or clearance of abnormal aggregate proteins. Using biophysical techniques, we evaluated the effects of two chaperones, human Hsp60 and bacterial GroEL, on the fibrillogenesis of Aβ

International audience; Dissolution of different rare earth oxides RE2O3 and cyclosilicate Ca3RE2(Si3O9)2 was studied at 1200 °C in a pseudo-ternary CAS melt. This investigation is relevant to CMAS resistant thermal barrier coatings (TBC) used in aircraft engines. CMAS is a generic term for the molten siliceous deposits resulting from the ingestion of mineral particles with the intake air. The aim was to assess the influence of the rare earth on the reaction kinetics, solubility limits and underlying phase equilibria in a model CAS melt. RE2O3 (RE = Nd, Sm, Gd, Dy and Yb) were selected to span a wide range of trivalent lanthanide sesquioxides and Lewis basicities. Powders dispersed in CAS glass-beads were reacted at 1200 °C and quenched after several durations. All the RE2O3 led to the formation of metastable apatite, and then to stabilization of cyclosilicate in CAS. Disilicate Yb2Si2O7 was also obtained in Yb2O3 bead-sample during early-stage of interaction. However, RE2O3 oxide basicity has a direct influence on silicates (apatite, disilicate and cyclosilicate) solubility limits in CAS, on RE-apatite crystal growth as well as on induction time for RE-cyclosilicate nucleation. The results are discussed in the light of crystal chemistry, thermodynamic considerations and RE cation field strength (Z/r²) which is alternative to define oxide basicity.

The energetic stability and oxidation behaviour of quaternary chromium silicides mainly depends on their chromium content. In this work, the pseudolamellar crystal structures of six representatives of the X3T2(T1-xCrx)2Si6 compounds (X = Nb or Ti and T = Fe, Co or Ni) are determined by resonant X-ray diffraction using the synchrotron facility, combined with calculations based on the density functional theory. Experimentally, the transition metal positions are determined using the anomalous scattering effect close to the energy absorption threshold. First principles calculations carried out on the as-determined structures show that the preferential site occupations are explained by thermodynamic arguments. Theoretical calculations highlight the influence of Cr atoms on the lattice parameters, and reveal that the experimental Cr content corresponds to the amount required to reach the equilibrium between X3T2(T1-xCrx)2Si6 and X4T4Si7.

Background and Objective: Patients with End- Stage Kidney Disease (ESKD) have a unique cardiovascular risk. This study aims at predicting, with a certain precision, death and cardiovascular diseases in dialysis patients. Methods: To achieve our aim, machine learning techniques have been used. Two datasets have been taken into consideration: the first is an Italian dataset obtained from the Istituto di Fisiologia Clinica of Consiglio Nazionale delle Ricerche of Reggio Calabria; the second is an American dataset provided by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) repository. From each one we obtained 5 datasets, according to the outcome of interest. We tested different types of algorithm (both linear and non-linear), but the final choice was to use Support Vector Machine. In particular, we obtained the best performances using the non-linear SVC with RBF kernel algorithm, optimizing it with GridSearch. The last is an algorithm useful to search the best combination of hyper-parameters (in our case, to find the best couple (C, γ)), in order to improve the accuracy of the algorithm. Results: The use of non-linear SVC with RBF kernel algorithm, optimized with GridSearch, allowed to obtain an accuracy of 95.25% in the Italian dataset and of 92.15% in the American dataset, in a timeframe of 2.5 years,in the prediction of Ischaemic Heart Disease. A worse performance was obtained for the other outcomes. Conclusions: The machine learning-based approach applied in our study is able to predict, with a high accuracy, the outbreak of cardiovascular diseases in patients on dialysis.

Alzheimer's disease is a chronic neurodegenerative disease characterized by the accumulation of pathological aggregates of amyloid beta peptide. Many efforts have been focused on understanding peptide aggregation pathways and on identification of molecules able to inhibit aggregation in order to find an effective therapy. As a result, interest in neuroprotective proteins, such as molecular chaperones, has increased as their normal function is to assist in protein folding or to facilitate the disaggregation and/or clearance of abnormal aggregate proteins. Using biophysical techniques, we evaluated the effects of two chaperones, human Hsp60 and bacterial GroEL, on the fibrillogenesis of Aβ1-42. Both chaperonins interfere with Aβ1-42 aggregation, but the effect of Hsp60 is more significant and correlates with its more pronounced flexibility and stronger interaction with ANS, an indicator of hydrophobic regions. Dose-dependent ThT fluorescence kinetics and SAXS experiments reveal that Hsp60 does not change the nature of the molecular processes stochastically leading to the formation of seeds, but strongly delays them by recognition of hydrophobic sites of some peptide species crucial for triggering amyloid formation. Hsp60 reduces the initial chaotic heterogeneity of Aβ1-42 sample at high concentration regimes. The understanding of chaperone action in counteracting pathological aggregation could be a starting point for potential new therapeutic strategies against neurodegenerative diseases.

Background Old patients with end-stage kidney disease (ESKD) represent an increasing segment of the ESKD population maintained on chronic dialysis treatment. Quality of life (QoL) is notoriously poor in ESKD but relationship between QoL and mortality has not been investigated in the old dialysis population. The objective of this study is to investigate the relationship between QoL and mortality in the old dialysis population. Methods Quality of Life was measured by the Rand- QoL Short Form 36 questionnaires in a multicentre, perspective cohort study including 253 very old patients (age ≥ 75 years) on chronic dialysis. Prognostic power of QoL was assessed applying C-statistics. Results In multivariate statistical models including a series of demographic and clinical variable physical function and general health maintained an independent relationship with survival (P ≤ 0.01). In analyses testing the prognostic value of these two SF36 components physical functioning was the component adding the highest explanatory power to standard demographic and clinical risk factors (+5.7%). Furthermore, the same parameter increased by 4.5% the discriminant power by the Harrell’s C Index, improved risk reclassification by the 20% (P = 0.003) and model calibration by the 83%. Conclusions In the very old dialysis population the physical function component of the SF36 is the QoL component holding the highest predictive power for mortality among the eight components of this instrument. As the discrimination power and risk reclassification ability by physical functioning is of degree relevant for clinical practice, such a measure has potential for refining prognosis and informing exercise programs in this population.

Light carries energy and therefore is source of a gravitational field. In the paper it is proven, in particular, that a laser beam is source of non-linear gravitational waves corresponding, from a quantum point of view, to spin-1 massless particles. This fact suggests both a possible solution to the old problem on the lack of gravitational attraction between two laser beams moving parallel and a new derivation of the Generalized Uncertainty Principle.

We consider in \begin{document}$ \mathbb R^3 $\end{document} the singularly perturbed Schrodinger-Poisson system \begin{document}$ \begin{equation*} \begin{cases} - \varepsilon^2\Delta v+V(x)v+\phi(x)v = f(v)\\ - \Delta\phi = v^2 . \end{cases} \end{equation*} $\end{document} Using variational techniques, we construct solutions which concentrate around the saddle points of the external potential \begin{document}$ V $\end{document} , as \begin{document}$ \varepsilon \rightarrow 0 $\end{document} .

International audience; Curcumin is a natural polyphenol able to bind the amyloid beta peptide, which is related to Alzheimer's disease, and modify its self-assembly pathway. This paper focuses on a multi-disciplinary study that starts from the design of curcumin-like compounds with the key chemical features required for inhibiting amyloid beta aggregation, and reports the effects of these compounds on the in vitro aggregation of amyloid beta peptides. Chemoinformatic screening was performed through the calculation of molecular descriptors that were able to highlight the drug-like profile, followed by docking studies with an amyloid beta peptide fibril. The computational design underlined two different scaffolds that were easily synthesized in good yields. In vitro experiments, ranging from fluorescence spectroscopy and confocal microscopy up to small angle X-ray scattering, provided evidence that the synthesized compounds are able to modify the aggregation pattern of amyloid beta peptides both in the secondary structures, and in terms of the overall structure dimensions. The cytotoxic potential of the synthesized compounds was finally tested in vitro with a model neuronal cell line (LAN5). The overall view of this study suggests new concepts and potential difficulties in the design of novel drugs against diverse amyloidoses, including Alzheimer's disease

Environmental/thermal barrier coatings (E/TBCs) of yttria partially stabilised zirconia (YSZ), gadolinium zirconate (GZO) and a combination of Y2SiO5 and GZO were applied on a Nb/Nb5Si3-based alloy with the nominal composition of Nb-25Ti-8Hf-2Cr-2Al-16Si (at%). A B-containing M7Si6-based (M=Ti, Nb, Fe, Cr) layer produced by pack cementation was used as bond coat. The ceramic topcoats were manufactured by electron-beam physical vapour deposition (YSZ and GZO) and magnetron sputtering (Y2SiO5).The different E/TBC systems were tested under cyclic oxidation conditions in air at 1100 and 1200°C. Lifetimes exceeding 1000 cycles of 1h dwell time at 1100°C were determined. The YSZ, GZO and combined Y2SiO5+GZO topcoats did not spall off during the maximum exposure time, exhibiting good adherence to the thermally grown oxide scale which consisted of mixed oxides of Fe,Ti, Cr and Nb embedded in silica. For the E/TBC systems with YSZ and GZO which were thermally cycled at 1200°C, lifetimes up to 850 cycles were measured; that of the system with a combined Y2SiO5+GZO topcoat exceeded again 1000 cycles.

In the USA, the increase in the prevalence of obesity in the general population has been accompanied by a marked increase in the prevalence and incidence of obesity in the dialysis population. However, secular trends of body mass index (BMI) have not been investigated in European renal registries.We investigated the secular trend of BMI across 18 years (1994-2011) in two haemodialysis (HD) registries (Calabria in southern Italy and Emilia in northern Italy) on a total of 16 201 prevalent HD patients and in a series of 3559 incident HD patients. We compared trends in BMI for HD patients with those in the background general population of the same regions.The average BMI rose from 23.5 kg/m(2) in 1994 to 25.5 (+8.5%) in 2011 in the Calabria registry and from 23.7 in 1998 to 25.4 (+7.1%) in 2011 in the Emilia registry (P0.001). The proportion of obese patients (i.e. with BMI30 kg/m(2)) rose from 6 to 14% in Calabria and from 6 to 16% in Emilia (P0.001). These patterns were fully confirmed in incident patients and were mirrored by a substantial decline in the prevalence of underweight-normal and underweight (P0.001) patients. Of note, the steepness of the increase in BMI in haemodialysis patients was 3.7 times more pronounced than that in the coeval, age- and sex-matched general population of Calabria and Emilia.In two regional haemodialysis registries in Italy a steady increase in overweight and obese patients is observed. These patterns are more pronounced than those found in the general population. If further confirmed in other European haemodialysis cohorts, these findings may have relevant public health implications.

Using variational techniques we prove an eigenvalue theorem for a stationary p(x)-Kirchhoff problem, and provide an estimate for the range of such eigenvalues. We employ a specific family of test functions in variable-exponent Sobolev spaces. Our approach permits to handle both non-degenerate and degenerate Kirchhoff coefficients.

We explore the multiplicity of weak solutions to a nonlocal equation in governed by a fractional power of the p-Laplacian combined with a Kirchhoff-type term. The nonlinearity involves two real parameters, one of which is of perturbing nature, and can overpower the critical fractional exponent. Our arguments rely upon the variational apparatus; the lack of compactness of the Sobolev embeddings is circumvented by the use of convenient weight functions.

Corrosion by molten phases leads to severe corrosion of heat exchangers in waste-to-energy plants. In addition, the presence of heavy metal chlorides in ash deposit increases degradation at low temperature due to the formation of highly corrosive molten phases. In this study, two heat exchanger materials, a low alloy steel (16Mo3) and a nickel based alloy (Inconel 625) were exposed in air to three different synthetic ashes, with various chloride contents, including ZnCl2 at isothermal temperatures of 450 and 650 °C in a muffle furnace. After the test, thickness and mass losses were evaluated on two separate samples, and metallographic cross sections of the specimens were characterized via SEM/EDX analyses. Both measurement results were in good agreement and showed that the corrosion observed on both materials was higher in the presence of zinc chloride in ash at 450 °C than in ashes without heavy metal chloride at 650 °C.