Bovine-Derived Hydroxyapatite (BHAp) is Ca-deficient natural hydroxyapatite with several ions substitutions that play a crucial role in its biomimetic behavior. Natural quantities of ions such as ...Mg2+ and CO32– increase the bioactivity and the biological performance of BHAp compared to stoichiometric hydroxyapatite (HAp). In this contribution, BHAp powder was obtained from two years old bovines and thermally sprayed by Atmospheric Plasma Spray (APS) and High-Velocity Oxygen Fuel (HVOF) on 304L stainless steel substrates. BHAp coatings morphology and structure were analyzed by scanning electron microscopy (SEM), Fourier Transformed Infra-Red (FTIR) spectroscopy and Rietveld refinements of the coatings grazing incident X-ray diffraction (GIXRD) patterns. The bioactivity of the coatings was evaluated following the modifications of its structure and surface morphology after immersion in simulated body fluid (SBF) during 3, 5 and 10 days, by SEM and GIXRD. The Ca, P and Mg concentration in SBF was also measured by inductively coupled plasma optical emission spectrometry (ICP-OPS). The obtained BHAp powder was highly crystalline and mainly a B-type HAp. The main differences between BHAp and HAp are CO32– and the Mg2+ contents, which lead to the formation of dolomite in the crystalline content (48.75 wt%) during HVOF spraying. APS coating did not exhibit any secondary phases in its crystalline content. The typical polyhedral grain apatite layer was evident after 3 days of immersion in SBF for both coatings. However, SEM micrographs of HVOF coatings show delamination after 5 days of immersion. Thus, the dolomite phase is detrimental for coating stability and bioactivity.
•BHAp deposited by HVOF leads to the formation of the dolomite phase.•BHAp APS coating does not show any secondary phases in its crystalline content.•BHAp APS coating shows the formation of apatite layer after 3 days in SBF.•BHAp HVOF coating shows the formation of apatite layer after 3 days in SBF.•Dolomite is detrimental for the BHAp coating stability during immersion in SBF.
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•Scalable reactor configuration to produce nanomaterials at low cost.•Synthesis of Fe3C/C core shell from ferrocene and ethylene glycol.•One-step synthesis of a mesoporous absorbent ...magnetic material.•Magnetic separation of biomolecules with Fe3C/C core shell nanoparticles.
In this article we report the synthesis of a carbon powder with embedded magnetic nanoparticles. Precursors, ferrocene and ethylene glycol, were loaded in a quartz combustion tube and pyrolysed by microwave plasma under vacuum conditions. The synthesized powder was similar to graphite in texture, but strongly attracted by magnetic fields. Several analytical techniques were carried out, including X-ray Photoelectron Spectroscopy, Transmission and Scanning Electron microscopies, X-ray Diffraction and BET isotherm. The resulting material is a ramified framework of carbon, similar to activated carbon, with embedded Fe3C/C core-shell nanoparticles. BET analysis gives a type IV isotherm, common for mesoporous adsorbents. A protocol was developed for the purification of nucleic acids by magnetic separation. The material gives satisfactory results for DNA extraction. It is concluded that due to the non-toxicity nature of the C shells and the outstanding magnetic property of the Fe3C nanoparticles this absorptive carbonaceous material can be applied in fields of biomedicine or biotechnology.
This work is focused on the preparation of a multifunctional compound consisting of silver nanoparticles (AgNPs) embedded in a matrix of amorphous carbon previously loaded with Fe3C magnetic ...particles. The objective is to use the antibacterial properties of the AgNPs for environmental purposes, in such a way that the AgNPs can be recovered by physical means (magnetic separation). The synthesis method was direct from ferrocene, silver nitrate and polyethylene glycol placed in a reaction tube and pyrolyzed by a plasma produced under vacuum conditions. For this, a conventional microwave oven was used. The compound obtained is a black powder, with similar consistency to graphite, but it responds strongly to the application of magnetic fields. The material was thoroughly characterized by X-ray photoelectron, energy-dispersive X-ray spectroscopies; transmission and scanning electron microscopies; X-ray diffraction, as well magnetic characterizations using a vibrating sample magnetometer. The material showed a homogeneous dispersion of metal particles in the carbon matrix. We conclude that the combination of magnetic and antibacterial properties makes this material interesting for several applications through the use of magnetic separation protocols.
•AgNps/Fe3C/C composite synthesis from silver nitrate, ferrocene and ethylene glycol.•Novel reactor to produce nanomaterials from organic and metal-organic precursors.•Bactericidal magnetic composite powder.•Recoverable silver nanoparticles.•The bactericidal powder can be applied in magnetic separation protocols.
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•Poled-BNT are novel biomaterials with tunable in-vitro properties for bone repair.•Effect of surface polarity of BNT on apatite formation and cell viability.•Apatite growth and ...maturation are strongly influenced by surface polarity.
Poled (Bi0.5Na0.5)TiO3 ceramics were firstly evaluated in the present study for their potential application as a novel biomaterial for bone repair. The formation of bone-like apatite was only observed on polarized surfaces showing a clear influence of polarity on its growth and maturation process after bioactivity tests. A non-cytotoxic effect of (Bi0.5Na0.5)TiO3 ceramics on MC3T3-E1 cells was shown in the viability test. Cells spread along the surface showed slight differences in shape and size due to polarity. Bioactive and non-cytotoxic behavior exhibited by poled (Bi0.5Na0.5)TiO3 ceramics makes them a promising material with tunable in-vitro properties for biomedical applications.
An experimental approach based on design of experiments, process maps and the analysis of deposition first stages to improve the biocompatibility of High-Velocity Oxygen Fuel (HVOF) hydroxyapatite ...(HAp) coatings is here presented. A two-level design of three factors (23) was performed using the stand-off distance (SOD), the fuel‑oxygen ratio (F/O) and the powder feed rate (PFR). The effect of these experimental factors on the first stages of the coating formation was investigated to study the physical state of the particles before and after impacting the substrate. This study allowed the selection of the most suitable deposition parameter combinations to obtain HAp coatings with optimal crystallinity (>45%), Ca/P ratio (approx. 1.67), phase content (>95% of HAp), which guarantee the coatings mechanical stability and biocompatibility. The behavior of the coating within simulated body fluid (SBF) and cell culture (hFOB) was studied to analyze the apatite layer formation and the extracts cytotoxicity on human osteoblasts, respectively. The results show that the F/O ratio is the most influential factor on temperature and velocity on the in-flight particles and therefore on the coating properties. The SBF results confirmed the formation of an apatite layer after 14 days of immersion. Finally, the mitochondrial activity, measured by the MTS assay, and cell membrane integrity measured by LDH liberation assays, show that the coating released material does not induce toxicity on the exposed cells.
•Optimized parameters for deposition of high quality HAp coatings by HVOF are here reported.•DoE methodologies and statistical analysis allowed to understand HAp coating formation by HVOF.•The leaching products generated by the HAp coatings deposited by HVOF do not induce cytotoxicity.
Environmental and genetic factors may modify or contribute to the phenotypic differences observed in multigenic and monogenic diseases, such as cystic fibrosis (CF). An analysis of modifier genes can ...be helpful for estimating patient prognosis and directing preventive care. The aim of this study is to determine the association between seven genetic variants of four modifier genes and CF by comparing their corresponding allelic and genotypic frequencies in CF patients (n = 81) and control subjects (n = 104). Genetic variants of MBL2 exon 1 (A, B, C and D), the IL-8 promoter (-251 A/T), the TNFα promoter (TNF1/TNF2), and SERPINA1 (PI*Z and PI*S) were tested in CF patients and control subjects from northeastern Mexico by PCR-RFLP.
The TNF2 allele (P = 0.012, OR 3.43, 95% CI 1.25-9.38) was significantly associated with CF under the dominant and additive models but was not associated with CF under the recessive model. This association remained statistically significant after adjusting for multiple tests using the Bonferroni correction (P = 0.0482). The other tested variants and genotypes did not show any association with the disease.
An analysis of seven genetic variants of four modifier genes showed that one variant, the TNF2 allele, appears to be significantly associated with CF in Mexican patients.
Most of information regarding the construction of continuous cooling transformation (CCT) diagrams considers the decomposition of austenite above the critical transformation temperature Ac3. The ...development of new grades of multiphase advanced high-strength steels (AHSS) usually involves an intercritical annealing stage, making it necessary the construction of CCT diagrams from the intercritical range. The availability of CCT diagrams constructed from the intercritical austenite is practically non-existent in the open literature. The present research reports an approach for the design of AHSS based on the behavior of CCT diagrams calculated from the intercritical temperature range as a function of chemical composition. Changes in chemical composition were conducted to promote the fabrication of multiphase AHSS steels under conditions that simulate continuous annealing and galvanizing lines (CAGL). To validate the results obtained from computer simulations, the steel was then fabricated, processed at laboratory scale and subjected to thermal cycles that simulate CAGL. Although there is a good approximation between theoretical and experimental results, it was observed that the software presents some limitations regarding the effects of plastic deformation and carbon partitioning during the isothermal bainitic treatment (IBT) on the final microstructures.
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Human movement affects malaria epidemiology at multiple geographical levels; however, few studies measure the role of human movement in the Amazon Region due to the challenging conditions and cost of ...movement tracking technologies. We developed an open-source low-cost 3D printable GPS-tracker and used this technology in a cohort study to characterize the role of human population movement in malaria epidemiology in a rural riverine village in the Peruvian Amazon. In this pilot study of 20 participants (mean age = 40 years old), 45,980 GPS coordinates were recorded over 1 month. Characteristic movement patterns were observed relative to the infection status and occupation of the participants. Applying two analytical animal movement ecology methods, utilization distributions (UDs) and integrated step selection functions (iSSF), we showed contrasting environmental selection and space use patterns according to infection status. These data suggested an important role of human movement in the epidemiology of malaria in the Peruvian Amazon due to high connectivity between villages of the same riverine network, suggesting limitations of current community-based control strategies. We additionally demonstrate the utility of this low-cost technology with movement ecology analysis to characterize human movement in resource-poor environments.
We report observational evidence of highly turbulent ionized gas kinematics in a sample of 20 Lyman continuum (LyC) emitters (LCEs) at low redshift (
z
∼ 0.3). Detailed Gaussian modeling of optical ...emission line profiles in high-dispersion spectra consistently shows that both bright recombination and collisionally excited lines can be fitted as one or two narrow components with intrinsic velocity dispersion of
σ
∼ 40 − 100 km s
−1
, in addition to a broader component with
σ
∼ 100 − 300 km s
−1
, which contributes up to ∼40% of the total flux and is preferentially blueshifted from the systemic velocity. We interpret the narrow emission as highly ionized gas close to the young massive star clusters and the broader emission as a signpost of unresolved ionized outflows, resulting from massive stars and supernova feedback. We find a significant correlation between the width of the broad emission and the LyC escape fraction, with strong LCEs exhibiting more complex and broader line profiles than galaxies with weaker or undetected LyC emission. We provide new observational evidence supporting predictions from models and simulations; our findings suggest that gas turbulence and outflows resulting from strong radiative and mechanical feedback play a key role in clearing channels through which LyC photons escape from galaxies. We propose that the detection of blueshifted broad emission in the nebular lines of compact extreme emission-line galaxies can provide a new indirect diagnostic of Lyman photon escape, which could be useful to identify potential LyC leakers in the epoch of reionization with the JWST.
Recently, intense emission from nebular C
III
and C
IV
emission lines have been observed in galaxies in the epoch of reionization (
z
> 6) and have been proposed as the prime way of measuring ...their redshift and studying their stellar populations. These galaxies might represent the best examples of cosmic reionizers, as suggested by recent low-
z
observations of Lyman continuum emitting galaxies, but it is hard to directly study the production and escape of ionizing photons at such high redshifts. The ESO spectroscopic public survey VANDELS offers the unique opportunity to find rare examples of such galaxies at cosmic noon (
z
∼ 3), thanks to the ultra deep observations available. We have selected a sample of 39 galaxies showing C
IV
emission, whose origin (after a careful comparison to photoionization models) can be ascribed to star formation and not to active galactic nuclei. By using a multiwavelength approach, we determined their physical properties including metallicity and the ionization parameter and compared them to the properties of the parent population to understand what the ingredients are that could characterize the analogs of the cosmic reionizers. We find that C
IV
emitters are galaxies with high photon production efficiency and there are strong indications that they might also have a large escape fraction: given the visibility of C
IV
in the epoch of reionization, this could become the best tool to pinpoint the cosmic reioinzers.
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