Characterization of relapsing-remitting multiple sclerosis patients using support vector machine classifications of functional and diffusion MRI data.

Multiple Sclerosis patients' clinical symptoms do not correlate strongly with structural assessment done with traditional magnetic resonance images. However, its diagnosis and evaluation of the disease's progression are based on a combination of this imaging analysis complemented with clinical examination. Therefore, other biomarkers are necessary to better understand the disease. In this paper, we capitalize on machine learning techniques to classify relapsing-remitting multiple sclerosis patients and healthy volunteers based on machine learning techniques, and to identify relevant brain areas and connectivity measures for characterizing patients. To this end, we acquired magnetic resonance imaging data from relapsing-remitting multiple sclerosis patients and healthy subjects. Fractional anisotropy maps, structural and functional connectivity were extracted from the scans. Each of them were used as separate input features to construct support vector machine classifiers. A fourth input feature was created by combining structural and functional connectivity. Patients were divided in two groups according to their degree of disability and, together with the control group, three group pairs were formed for comparison. Twelve separate classifiers were built from the combination of these four input features and three group pairs. The classifiers were able to distinguish between patients and healthy subjects, reaching accuracy levels as high as 89% ± 2%. In contrast, the performance was noticeably lower when comparing the two groups of patients with different levels of disability, reaching levels below 63% ± 5%. The brain regions that contributed the most to the classification were the right occipital, left frontal orbital, medial frontal cortices and lingual gyrus. The developed classifiers based on MRI data were able to distinguish multiple sclerosis patients and healthy subjects reliably. Moreover, the resulting classification models identified brain regions, and functional and structural connections relevant for better understanding of the disease

Lithium abundances and extra mixing processes in evolved stars of M67

Aims. We present a spectroscopic analysis of a sample of evolved stars in M67 (turn-off, subgiant and giant stars) in order to bring observational constraints to evolutionary models taking into account non-standard transport processes. Methods. We determined the stellar parameters (Teff, log g, [Fe/H]), microturbulent and rotational velocities and, Lithium abundances (ALi) for 27 evolved stars of M67 with the spectral synthesis method based on MARCS model atmospheres. We also computed non-standard stellar evolution models, taking into account atomic diffusion and rotation-induced transport of angular momentum and chemicals that were compared with this set of homogeneous data. Results. The lithium abundances that we derive for the 27 stars in our sample follow a clear evolutionary pattern ranging from the turn-off to the Red Giant Branch. Our abundance determination confirms the well known decrease of lithium content for evolved stars. For the first time, we provide a consistent interpretation of both the surface rotation velocity and of the lithium abundance patterns observed in an homogeneous sample of TO and evolved stars of M67. We show that the lithium evolution is determined by the evolution of the angular momentum through rotation-induced mixing in low-mass stars, in particular for those with initial masses larger than 1.30 M_\odot at solar metallicity.Comment: 13 pages, 8 figure

Precipitation kinetics in a 10.5% Cr heat resistant steel: experimental results and simulation by TC-PRISMA / DICTRA

The precipitation kinetics of secondary phases in a 10.5%Cr heat resistant steel, designed by the authors, was studied experimentally and theoretically. Experimental data of nucleation, growth and coarsening stages for M23C6 carbides, V-MX, Nb-MX and Laves phase were obtained by HRTEM-characterization on samples after tempering (780 degrees C/2 h) and isothermally aging for 1440 h and 8760 h at 650 degrees C. Theoretical studies of precipitation behavior of M23C6 and Laves phase were carried out by TC-PRISMA and complemented with DICTRA. A good fit between TC-PRISMA simulation and experimental results was obtained for M23C6 carbides considering a heterogeneous nucleation in grain boundaries, a semi-coherent interfacial energy of 0.3 J/m(2), and decreasing the atomic mobility along grain boundary in order to include the effect of B. Experiments and simulation indicate a low coarsening rate for M23C6 carbides. Furthermore, precipitation of Laves phase at 650 degrees C was simulated by TC-PRISMA considering the effect of W and Si segregation at grain boundary, prior to the beginning of the nucleation and growth processes. Therefore, thermodynamic and kinetic boundary conditions were changed purposely in TC-PRISMA. Best agreement with the experimental results was obtained for an interfacial energy of 0.6 J/m(2) and heterogeneous nucleation in grain boundary.DOCTORADO NACIONAL 21130630 project "FONDECYT de Iniciacion" from the Chilean Government 11110098 11121384 "Proyecto de insercion de capital humano avanzado" from the Chilean Government 79112035 project "FONDECYT" from the Chilean Government 1150457" Create-Net project H2020-MSCA-RISE/64401

Formulation of a multifunctional coating based on polyphenols extracted from the Pine radiata bark and functionalized zinc oxide nanoparticles: Evaluation of hydrophobic and anticorrosive properties

With the purpose of improving the protection of steel ASTM A36 from corrosion, in this paper the use of tannin as an inhibitor was studied by incorporating it in an epoxy resin along with zinc oxide nanoparticles functionalized with 3-aminopropyltriethoxysilane (APTES) in concentrations of 1, 3, and 5w/w. Electrochemical techniques such as polarization curves and EIS for the characterization of the anticorrosive properties, SKP for the study of coating delamination with the substrate, contact angle measurement and other standardized methods were used for the evaluation of the properties of the film. The results of the polarization curves revealed that the corrosion current density of the steel (icorr) decreases markedly with the addition of the tannin extract by changing the cathodic behavior without affecting the active anodic behavior. Likewise, the EIS analysis showed that the coatings with surface modified nanoparticles provide an excellent protection against corrosion that is complemented by the protective layer of the tannin-iron complex formed and the same was confirmed by FTIR spectroscopy after exposing the plates to accelerated corrosion tests in salt spray and weathering chamber. Finally, it could be demonstrated that the incorporation of zinc oxide nanoparticles in the coating formulation subtly improves the film properties and likewise, partially increases the hydrophobicity. © 2019 Elsevier B.V

Comparative Study of the Antimicrobial Effect of Nanocomposites and Composite Based on Poly(butylene adipate-co-terephthalate) Using Cu and Cu/Cu2O Nanoparticles and CuSO4

Abstract Nanocomposites and a composite based on poly(butylene adipate-co-terephthalate) (PBAT) were synthesized using commercial copper nanoparticles (Cu-NPs), copper/cuprous oxide nanoparticles (Cu|Cu2O-NPs), and copper sulfate (CuSO4), respectively. The Cu|Cu2O-NPs were synthesized using chemical reduction and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The synthesis of Cu|Cu2O-NPs yielded a mixture of Cu and Cu2O, with metal Cu having a spherical morphology of approximately 40 nm in diameter and Cu2O with a diameter of 150 nm. To prepare the nanocomposites (NCs) and the composite material (MC), the NPs and the CuSO4 salt were incorporated into the PBAT matrix in concentrations of 1, 3, and 5% p/p via an ex situ method. Fourier transform infrared spectroscopy (FTIR), a tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and agar diffusion assays were used for structural, thermomechanical, and antimicrobial characterization. Results showed that the reinforcements did not modify the chemical structure of the PBAT and only slightly increased the percentage of crystallization. The mechanical and thermal properties of the PBAT did not change much with the addition of fillers, except for a slight increase in tensile strength and thermal stability, respectively. The agar diffusion antimicrobial assays showed that the NCs and MCs had good inhibitory responses against the nonresistant strains Enterococcus faecalis, Streptococcus mutans, and Staphylococcus aureus. The MCs based on CuSO4 had the highest biocidal effect, even against the resistant bacteria Acinetobacter baumannii

Fabrication of a novel hybrid AlMg5/SiC/PLZT metal matrix composite produced by hot extrusion

A novel type of piezoelectric aluminium-based hybrid composite containing silicon carbide (SiC) and piezoelectric lead lanthanum zirconate titanate (PLZT) was prepared using powder metallurgy technique followed by sintering at 630. °C and hot extrusion at 500. °C. The volume fraction of PLZT particles varied as 0%, 5%, 10% and 15% with fixed weight 1. wt.% of SiC respectively in the composite and its effects on the microstructure as well as the damping nature of the composite were studied. The microstructure of composites was analysed by scanning electron microscope (SEM) and electron microprobe, and damping behaviour was investigated using Dynamic Mechanical Analysis (DMA) as function of temperature. Microstructural results attested the homogeneity of two different reinforcements in the composite and thus confirmed hot extrusion process had shown promising route for obtaining homogenous and dense metal matrix composites. DMA studies of homogenous hybrid MMCs indicated that the increase in wt.% of piezoelectric PLZT particles improved the damping properties.Authors CMW and Koduri Ramam acknowledge and are grateful to CONICYT for Doctoral Research Fellowship and also acknowledge Universidad Carlos III, Spain for hosting internship to carryout doctoral research work and Universidad del Biobío for characterization support. Authors Koduri Ramam and CMW greatly acknowledge Fondecyt Research Project Number 1110583 for the financial support with the research project and characterization equipment