Improvement of mechanical and thermal properties of poly(3-hydroxybutyrate) (PHB) blends with surface-modified halloysite nanotubes (HNT)

[EN] The effect of two hydrophobic treatments on the hydrophilic nature of halloysite nanotubes (HNT) was studied in this research work: a silanization with (3-glycidyloxypropyl) trimethoxysilane (GLYMO) and a surface treatment with a natural aromatic compound, i.e. caffeic acid (CA). In addition, the effect of 3¿wt% of unmodified HNT, silanized HNT (HNTSIL) and caffeic acid-modified HNT (HNTCA) on mechanical, thermal and morphological properties of a binary blend of poly(3-hydroxybutyrate) (PHB) and poly(¿-caprolactone) (PCL) with a weight ratio of 75/25, respectively was evaluated. These blends and their corresponding composites with HNT were partially compatibilized by reactive extrusion with dicumyl peroxide (DCP) and further processed by injection molding. The effectiveness of the surface treatments on HNT was followed by Fourier transformed infrared spectroscopy (FTIT), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and contact angle measurements. The obtained results suggested a clear hydrophobizing effect of both surface treatments on HNT but the hydrophobic nature the caffeic acid treatment can provide to HNT is greater than silanization. FESEM study on HNT-loaded PHB/PCL blends showed increased compatibility between modified-HNT and the polymeric matrix, as well as a better particle dispersion. In particular, 3¿wt% HNTCA lead to an increase in tensile strength and elongation at break of 11.4% and 74%, respectively, with regard to composites with unmodified HNT. In addition, thermal analysis, evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), revealed a decrease in the melt peak temperature of 6.5¿°C for composites with 3¿wt% HNTCA as well a delay in the onset degradation temperature, thus leading to a broader processing window which enhances PHB processing by conventional techniques.This work was supported by the Ministry of Economy and Competitiveness (MINECO) [MAT2017-84909-C2-2-R]. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports for the financial support through a FPU grant [FPU13/06011].Garcia-Garcia, D.; Garcia-Sanoguera, D.; Fombuena, V.; López-Martínez, J.; Balart, R. (2018). Improvement of mechanical and thermal properties of poly(3-hydroxybutyrate) (PHB) blends with surface-modified halloysite nanotubes (HNT). Applied Clay Science. 162:487-498. https://doi.org/10.1016/j.clay.2018.06.042S48749816

Measuring the magnetic moment density in patterned ultrathin ferromagnets with submicron resolution

We present a new approach to infer the surface density of magnetic moments $I_s$ in ultrathin ferromagnetic films with perpendicular anisotropy. It relies on quantitative stray field measurements with an atomic-size magnetometer based on the nitrogen-vacancy center in diamond. The method is applied to microstructures patterned in a 1-nm-thick film of CoFeB. We report measurements of $I_s$ with a few percent uncertainty and a spatial resolution in the range of $(100$ nm)$^2$, an improvement by several orders of magnitude over existing methods. As an example of application, we measure the modifications of $I_s$ induced by local irradiation with He$^+$ ions in an ultrathin ferromagnetic wire. This method offers a new route to study variations of magnetic properties at the nanoscale.Comment: 9 pages and 7 figures including main text and Supplemental Informatio

MapReduce-based Solutions for Scalable SPARQL Querying

The use of RDF to expose semantic data on the Web has seen a dramatic increase over the last few years. Nowadays, RDF datasets are so big and rconnected that, in fact, classical mono-node solutions present significant scalability problems when trying to manage big semantic data. MapReduce, a standard framework for distributed processing of great quantities of data, is earning a place among the distributed solutions facing RDF scalability issues. In this article, we survey the most important works addressing RDF management and querying through diverse MapReduce approaches, with a focus on their main strategies, optimizations and results

Analysis of Silage Fermentation Characteristics Using Transflectance Measurements by Near Infrared Spectroscopy

The fermentation end products as lactic acid, volatile fatty acids and ammonia-nitrogen, are important indicators of the efficiency of silage fermentation and are closely related to nutritive value of them (Jaster, 1995). Drying is problematic in the case of silage as many fermentation products are volatile and may get lost during the drying process. This may be a reason why NIR technology is being little used for the evaluation of silage fermentation characteristics. The feasibility of using near infrared transflectance spectroscopy to evaluate the content in fermentation end products of grass and maize fresh silage was investigated in this study

Diffractive Corneal Inlays: A New Concept for Correction of Presbyopia

A new class of corneal inlays for treatment of presbyopia is described, which uses diffraction as the working principle. The inlay consists of an opaque disk with a small central aperture surrounded by an array of micro-holes that are distributed following the order of a given Fresnel zone plate having N zones. In this way, the central hole of the disk produces an extension of the depth of focus of the eye for distance vision and contributes to the zero order of diffraction, and the light diffracted by the micro-holes in the periphery produces a real focus for near vision. In our general design, the number of zones and the diameter of the central hole are free parameters that can be used to design customized devices with different addition power and near-focus intensity. Two different designs are analyzed to show this property. In the analysis, we employed a ray tracing software to study the performance of the new inlays in the two different model eyes. The results are compared with those obtained with a model of the small-aperture inlay that is currently in the market. The different merit functions used in the comparison and the image simulations performed with the inlays in the model eyes show the excellent performance of our proposal

Internalizing Symptoms Mediate the Relation Between Acute Pain and Autism in Adults.

Research on pain in autism spectrum disorder (ASD) is in its infancy, with almost nothing known about how individual differences may predicting pain response in ASD. In the present study, 45 adults (28 male, age 22-48 years) with diagnoses of autism and intellectual delay were observed during vaccination or dental cleaning and their pain behaviours coded and measures of autism symptom severity, anxiety, depression and obsessivity taken. Our findings showed that greater autism severity predicted greater pain response which was partially mediated by anxiety and depression. These data suggest that mental health symptoms are important when considering pain response in autism. Mood must therefore be considered in future research on pain in ASD as well as clinical pain management

A new trifocal corneal inlay for presbyopia

[EN] Corneal inlays (CIs) are the most recent surgical procedure for the treatment of presbyopia in patients who want complete independence from the use of glasses or contact lenses. Although refractive surgery in presbyopic patients is mostly performed in combination with cataract surgery, when the implantation of an intraocular lens is not necessary, the option of CIs has the advantage of being minimally invasive. Current designs of CIs are, either: small aperture devices, or refractive devices, however, both methods do not have good performance simultaneously at intermediate and near distances in eyes that are unable to accommodate. In the present study, we propose the first design of a trifocal CI, allowing good vision, at the same time, at far, intermediate and near vision in presbyopic eyes. We first demonstrate the good performance of the new inlay in comparison with a commercially available CI by using optical design software. We next confirm experimentally the image forming capabilities of our proposal employing an adaptive optics based optical simulator. This new design also has a number of parameters that can be varied to make personalized trifocal CI, opening up a new avenue for the treatment of presbyopia.This work was supported by Ministerio de Ciencia e Innovacion, Spain (Grant PID2019-107391RB-I00) and by Generalitat Valenciana, Spain, (Grant PROMETEO/2019/048). D. Montagud-Martinez and V. Ferrando acknowledge the financial support from the Universitat Politecnica de Valencia, Spain (fellowships FPI-2016 and PAID-10-18, respectively)Furlan, WD.; Montagud-Martínez, D.; Ferrando, V.; Garcia-Delpech, S.; Monsoriu Serra, JA. (2021). A new trifocal corneal inlay for presbyopia. Scientific Reports. 11(1):1-8. https://doi.org/10.1038/s41598-021-86005-8S1811

Recycling of tailings from the Barruecopardo tungsten deposit for the production of glass

Tailings from tungsten mining activities in the vicinity of Barruecopardo (Salamanca) represent high environmental pollution. In this paper we present a study of the use of these wastes as raw materials for the manufacture of glass. This procedure aims to contribute to environmental remediation of mining areas through vitrification, a process which offers an alternative for stabilization of hazardous wastes. In addition, the marketing of the obtained product would provide an additional income to the mining areas. The chemical composition of the tailings to be used as raw materials was determined by X-ray fluorescence and their mineralogy by X-ray diffraction. Wastes are of granitic composition enriched in potentially toxic elements. For this study, a representative sample of mining wastes of sandy grain size was used to make the glass. On the basis of its composition, glass was formulated by adding 29.28 mass% of CaCO3 and 14.03 mass% of Na2CO3 and a green glass was produced. Crystallisation temperatures, obtained by DTA, were 875 and 1022 °C and the melting temperature was 1175 °C. The transition temperature of glass was of 644 °C. The temperatures for the fixed viscosity points, and the working temperatures were obtained. A thermal treatment induced devitrification to produce a glass-ceramic made of nepheline and wollastonite. Leaching tests of the obtained glass confirm its capacity to retain potentially toxic elements

Chronic glaucoma using biodegradable microspheres to induce intraocular pressure elevation. Six-month follow-up

Background: To compare two prolonged animal models of glaucoma over 24 weeks of follow-up. A novel pre-trabecular model of chronic glaucoma was achieved by injection of biodegradable poly lactic-co-glycolic acid (PLGA) microspheres (10–20 µm) (Ms20/10) into the ocular anterior chamber to progressively increase ocular hypertension (OHT). Methods: Rat right eyes were injected to induce OHT: 50% received a suspension of Ms20/10 in the anterior chamber at 0, 2, 4, 8, 12, 16 and 20 weeks, and the other 50% received a sclerosing episcleral vein injection biweekly (EPIm). Ophthalmological clinical signs, intraocular pressure (IOP), neuroretinal functionality measured by electroretinography (ERG), and structural analysis of the retina, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) protocols using optical coherence tomography (OCT) and histological exams were performed. Results: Both models showed progressive neuroretinal degeneration (p < 0.05), and contralateral eye affectation. The Ms20/10 model showed a more progressive increase in IOP and better preservation of ocular surface. Although no statistical differences were found between models, the EPIm showed a tendency to produce thicker retinal and thinner GCL thicknesses, slower latency and smaller amplitude as measured using ERG, and more aggressive disturbances in retinal histology. In both models, while the GCL showed the greatest percentage loss of thickness, the RNFL showed the greatest and earliest rate of thickness loss. Conclusions: The intracameral model with biodegradable microspheres resulted more like the conditions observed in humans. It was obtained by a less-aggressive mechanism, which allows for adequate study of the pathology over longer periods. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Monte Carlo uncertainty propagation approaches in ADS burn-up calculations

In activation calculations, there are several approaches to quantify uncertainties: deterministic by means of sensitivity analysis, and stochastic by means of Monte Carlo. Here, two different Monte Carlo approaches for nuclear data uncertainty are presented: the first one is the Total Monte Carlo (TMC). The second one is by means of a Monte Carlo sampling of the covariance information included in the nuclear data libraries to propagate these uncertainties throughout the activation calculations. This last approach is what we named Covariance Uncertainty Propagation, CUP. This work presents both approaches and their differences. Also, they are compared by means of an activation calculation, where the cross-section uncertainties of 239Pu and 241Pu are propagated in an ADS activation calculation