Study of Electrochemical and Biological Characteristics of As-Cast Ti-Nb-Zr-Ta System Based on Its Microstructure

[EN] The quaternary Ti-Nb-Zr-Ta (TNZT) alloy was successfully cast-fabricated with the objective to be used in the medical field. Samples' microstructure was compared to CP-Ti and Ti-6Al-4V (control samples) and related to corrosion, ion release and biological properties. As-cast TNZT was formed with large grain sizes (285 m) compared to the ultrafine grain sizes of CP-Ti (11 m) and the + ultrafine grain sizes of 1.45 m and 0.74 m. Hardness and flexural elastic moduli (94 HV and 43 GPa) came close to the biological structures, such as dentin and enamel values. The ion release mechanism of as-cast TNZT was significantly lesser than CP-Ti and Ti-6Al-4V, which can be related to the difference in samples¿ grain sizes and chemical compositions. However, the corrosion rate was higher than for the control samples; this way offers corrosion properties inferior with respect to the properties obtained in the reference materials. Biological assays demonstrated that the two-cell (hDPSCs and MG-63) lineage studied presented good adhesion and capability to differentiate in bone cells on the as-cast TNZT surface, and no cytotoxicity effects were found. Details and reasons based on samples¿ microstructure are discussed.The authors thank the Spanish Ministerio de Economia y Competitividad for Research Project RTI2018-097810-B-I00 and the European Commission for FEDER funds.Correa Rossi, M.; Navarro, B.; Milian Medina, L.; Vicente-Escuder, Á.; Amigó, V. (2022). Study of Electrochemical and Biological Characteristics of As-Cast Ti-Nb-Zr-Ta System Based on Its Microstructure. Metals. 12(3):1-25. https://doi.org/10.3390/met1203047612512

Performance of Ti-15Mo alloy obtained by powder metallurgy route weakly alloyed with Fe/Cr elements

[EN] Ti-15Mo alloy can be an excellent choice as a biomaterial for prostheses. This is due to the combination of good mechanical properties and biocompatibility. The Mo is a stabilizing element of the ß phase, which provides a smaller elastic modulus, reducing the risk of stress shielding that induces bone resorption. The present work shows the effect of minor additions of Fe or Cr on flexural fracture toughness in Ti-15Mo alloys obtained by Powder Metallurgy. The electrochemical results indicated that the Ti-15Mo-1Cr, showed greater resistance to corrosion, related to lower ß grain size, less porosity content compared to the other conditions. As the Ti-15Mo-1Fe and Ti-15Mo-3Fe presented more porosity in their microstructure, the saline composition inside the pores is different in concentration and thus makes diffusion difficult compared to other regular and more homogeneous zones. Besides, was verified the effect of the large grain size that decrease the corrosion resistance of the Ti-15Mo-3Cr, demonstrated two influences in the corrosion resistance, porosity and grain size. Toughness decreases with the addition of both elements, more pronounced with Fe than Cr. It is related with lower densification, higher porosity and greater proportion of phase ¿ in grain boundary due to the higher resistance of diffusion of Mo in Ti when Fe is present, which leads to failure by brittle fracture at lower shear stresses.Correa Rossi, M.; López Navarro, P.; Vicente-Escuder, Á.; Amigó, V.; Segovia-López, F. (2022). Performance of Ti-15Mo alloy obtained by powder metallurgy route weakly alloyed with Fe/Cr elements. Social Science Research Network. 1-28. https://doi.org/10.2139/ssrn.400776212

Mechanical, Corrosion, and Ion Release Studies of Ti-34Nb-6Sn Alloy with Comparable to the Bone Elastic Modulus by Powder Metallurgy Method

[EN] The development of a Ti-34Nb-6Sn alloy by the powder metallurgy method, employing two different compaction conditions, A (100 MPa) and B (200 MPa), was carried out. To evaluate the feasibility of the Ti-34Nb-6Sn alloy as an implant biomaterial, microstructural and mechanical characterizations, as well as corrosion susceptibility and ion release tests, were performed. Results indicated microstructures dominated by the presence of -Ti phase and a lower percentage of -Ti and Nb phases. The porosity percentage decreased when the compaction pressure increased. Both conditions presented a good match between the elastic moduli of the alloy (14.0 to 18.8 GPa) and that reported for the bone tissue. The Ti, Nb and Sn ions released for both compaction conditions were within the acceptable ranges for the human body. Condition B showed higher corrosion resistance in comparison with condition A. Based on the obtained results, the produced porous Ti-34Nb-6Sn alloys are feasible materials for orthopedic implant applications.This research was funded by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (grant: 2017/13876-2; 2019/24237-6), by the Ministerio Español de Ciencia, Innovación y Universidades, with Grant RTI2018-097810-B-I00, and by the Instituto de Pesquisas Tecnológicas do Estado de São Paulo (IPT-SP). L.R.-R. acknowledges CONACyT for the PhD scholarship with number 465504.Correa Rossi, M.; Romero-Resendiz, L.; Leal Bayerlein, D.; Garcia Alves, AL.; Segovia-López, F.; Amigó, V. (2022). Mechanical, Corrosion, and Ion Release Studies of Ti-34Nb-6Sn Alloy with Comparable to the Bone Elastic Modulus by Powder Metallurgy Method. Powders. 1(1):3-17. https://doi.org/10.3390/powders10100023171

Evaluation of the influence of low Mg content on the mechanical and microstructural properties of beta titanium alloy

[EN] It was investigated in order to better understand the relationship between the low presence of Mg in the TieNbeSn alloy in its mechanical and microstructural properties by the powder metallurgy technique for biomedical application. The blended powders with the nominal composition of Tie34Nbe6Sn were obtained by milling at 200 rpm/40 min, compacted at 200 MPa. The sintering were carried out at 900 C/2 h and at 1110 C/2 h, followed by furnace cooling. The particle size was characterized by the dynamic image analyzer (DIA). The phases quantification and their microstructure were characterized by an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). The porosity was characterized by the Archimedes method and also bi-dimensionally by the Image J software. The mechanical tests were performed by the impulse excitation (Sonelastic ®) technique, in order to evaluate the elastic modulus (E) of the sintered materials and the hardness and resistance by the Rockwell method. The results indicated that the sintering at 1100 C in the materials with Mg, still had particles of Nb not diffused. The microstructure was basically formed by two phases with the presence of Nb non-diffused in all conditions except at 1100 C in the system without Mg. The b phase % for systems without and with Mg at 900 C was approximately 80% and 65%. At 1100 C, 76% and 78%. The E and hardness were 31 GPa and 226 MPa at 900 C; 49 GPa and 344 MPa at 1100 C for materials with Mg. The O and N content increased approximately 1.3 times when adding Mg powder.This work was supported by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo [grant: 2019/24237-6], by the Ministerio Espanol de Ciencia, Innovacion y Universidades with Grant RTI2018-097810-B-I00 and the Instituto de Pesquisas Tecnologicas do Estado de Sao Paulo (IPT-SP), in the development of materials, whom the authors thankCorrea Rossi, M.; Leal Bayerlein, D.; De Santi-Gouvea, E.; Haro Rodríguez, MV.; Vicente-Escuder, Á.; Amigó, V. (2021). Evaluation of the influence of low Mg content on the mechanical and microstructural properties of beta titanium alloy. Journal of Materials Research and Technology. 10:916-925. https://doi.org/10.1016/j.jmrt.2020.12.1039169251

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library

Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July–2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA—we release 4824 data cubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g., stellar and gas kinematics, emission-line and other maps) from the MaNGA Data Analysis Pipeline, and a new data visualization and access tool we call "Marvin." The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper, we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials, and examples of data use. Although SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V (2020–2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data

The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra

This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)

The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra

This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)

The 16th Data Release of the Sloan Digital Sky Surveys : First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra

This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).Peer reviewe