Acrylonitrile butadiene styrene-based composites with permalloy with tailored magnetic response

This work reports on tailoring the magnetic properties of acrylonitrile butadiene styrene (ABS)-based composites for their application in magnetoactive systems, such as magnetic sensors and actuators. The magnetic properties of the composites are provided by the inclusion of varying permalloy (Py—Ni75Fe20Mo5) nanoparticle content within the ABS matrix. Composites with Py nanoparticle content up to 80 wt% were prepared and their morphological, mechanical, thermal, dielectric and magnetic properties were evaluated. It was found that ABS shows the capability to include high loads of the filler without negatively influencing its thermal and mechanical properties. In fact, the thermal properties of the ABS matrix are basically unaltered with the inclusion of the Py nanoparticles, with the glass transition temperatures of pristine ABS and its composites remaining around 105 °C. The mechanical properties of the composites depend on filler content, with the Young’s modulus ranging from 1.16 GPa for the pristine ABS up to 1.98 GPa for the sample with 60 wt% filler content. Regarding the magnetic properties, the saturation magnetization of the composites increased linearly with increasing Py content up to a value of 50.9 emu/g for the samples with 80 wt% of Py content. A numerical model has been developed to support the findings about the magnetic behavior of the NP within the ABS. Overall, the slight improvement in the mechanical properties and the magnetic properties provides the ABS composites new possibilities for applications in magnetoactive systems, including magnetic sensors, actuators and magnetic field shielding.This project was supported by the PID program CDTI (EXP-00131900/IDI-20210369). Funding is from the Basque Government Industry Department under the ELKARTEK program. Support was received from the Portuguese Fundação para a Ciência e Tecnologia, grant SFRH/BPD/110914/2015

Electrospun magnetic ionic liquid based electroactive materials for tissue engineering applications

Functional electrospun fibers incorporating ionic liquids (ILs) present a novel approach in the development of active microenviroments due to their ability to respond to external magnetic fields without the addition of magnetic particles. In this context, this work reports on the development of magnetically responsive magneto-ionic fibers based on the electroactive polymer poly(vinylidene fluoride) and the magnetic IL (MIL), bis(1-butyl-3-methylimidazolium) tetrathiocyanatocobaltate ([Bmim]2[(SCN)4Co]). The PVDF/MIL electrospun fibers were prepared incorporating 5, 10 and 15 wt.% of the MIL, showing that the inclusion of the MIL increases the polar β-phase content of the polymer from 79% to 94% and decreases the crystallinity of the fibers from 47% to 36%. Furthermore, the thermal stability of the fibers decreases with the incorporation of the MIL. The magnetization of the PVDF/MIL composite fibers is proportional to the MIL content and decreases with temperature. Finally, cytotoxicity assays show a decrease in cell viability with increasing the MIL content.This research was funded by FCT—Fundação para a Ciência e Tecnologia (FCT) under the scope of the strategic funding of UID/FIS/04650/2020, and project PTDC/BTM-MAT/28237/2017. Moreover, the authors thank FCT for the research grant SFRH/BD/145345/2019 (LMC), SFRH/BD/148655/2019 (RMM), and D.M.C. and CR thank the FCT for the contract under the Stimulus of Scientific Employment 2020.02915.CEECIND and 2020.04163.CEECIND, respectively.The authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program. Technical and human support provided by IZO-SGI, SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully acknowledged

Beeswax multifunctional composites with thermal-healing capability and recyclability

Natural beeswax reinforced with conductive nanofillers allows solvent-free processing and presents remarkable functional response as piezoresistive and thermoresistive sensors with thermal healing capability. The low melting temperature of the composites, around 60 °C, allows additive manufacturing of conductive patterns with a high electrical conductivity of 50 S/m. Further, the graphene/beeswax composites show suitable deformation and temperature sensing characteristics based on the piezoresistive and thermoresistive sensitivities, around GF≈9 and S≈ 120 %/°C, respectively. Natural beeswax is a food and drug administration approved substance, and all graphene/beeswax composites present no cytotoxic behavior, demonstrating their potential use for biomedical applications. Proofs-of-concept demonstrate the conductive and thermal-healing properties of the screen-printed sensors developed both on paper and Kapton substrates, proving the applicability and multifunctionality of the developed materials. Finally, the multifunctional composites can be recycled and reused without losing their electrical and functional performances

Environmentally friendly carrageenan-based ionic-liquid driven soft actuators

UID/FIS/04650/2020 UID/QUI/0686/2020 LA/P/0008/2020 PID2019-106099RB-C43/AEI/10.13039/501100011033A naturally derived polymer based on iota carrageenan and different ammonium and imidazolium based ionic liquids (ILs) are used for the development of environmentally friendly soft actuators. The influence of IL content and type and solvent evaporation temperature on the morphological and physico-chemical properties of the materials was evaluated, together with the effect on actuator functional response. Independently of the IL content and type, and the solvent evaporation temperature, a non-porous structure is obtained. The incorporation of the IL within the polymer matrix does not affect the thermal stability but leads to a decrease in the Young modulus for the different IL/carrageenan samples. The highest influence was observed by using the [Ch][DHP] IL at a filler content of 40% w/w with a decrease in the Young modulus from 748 MPa for the neat polymer to 145 MPa for the [Ch][DHP]/carrageenan sample. Furthermore, the ionic conductivity of the samples increases with increasing IL content, with the highest values being 2.9 × 10-6 S cm-1 and 1.2 × 10-6 S cm-1 for the samples with 40% w/w of [Bmim][FeCl4] and [Ch][DHP], respectively. Regarding the soft actuator performance, the maximum displacement was obtained for the [Ch][DHP]/carrageenan sample with an IL content of 40% w/w, showing a maximum displacement of 5.8 mm at a DC applied voltage of 9 V.publishersversionpublishe

LINE-1 Evasion of Epigenetic Repression in Humans

Epigenetic silencing defends against LINE-1 (L1) retrotransposition in mammalian cells. However, the mechanisms that repress young L1 families and how L1 escapes to cause somatic genome mosaicism in the brain remain unclear. Here we report that a conserved Yin Yang 1 (YY1) transcription factor binding site mediates L1 promoter DNA methylation in pluripotent and differentiated cells. By analyzing 24 hippocampal neurons with three distinct single-cell genomic approaches, we characterized and validated a somatic L1 insertion bearing a 3' transduction. The source (donor) L1 for this insertion was slightly 5' truncated, lacked the YY1 binding site, and was highly mobile when tested in\ua0vitro. Locus-specific bisulfite sequencing revealed that the donor L1 and other young L1s with mutated YY1 binding sites were hypomethylated in embryonic stem cells, during neurodifferentiation, and in liver and brain tissue. These results explain how L1 can evade repression and retrotranspose in the human body

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Environmentally Friendlier Printable Conductive and Piezoresistive Sensing Materials Compatible with Conformable Electronics

Funding Information: This work was supported by the Portuguese Foundation for Science and Technology (FCT): projects UID/FIS/04650/2021, UIDP/05256/2020, UIDB/50006/2020, and UIDP/50006/2020, grants SFRH/BPD/110914/2015 (P.C.) and SFRH/BD/145741/2019 (M.F.), and Stimulus of Scientific Employments 2020.04028.CEECIND (C.M.C.), 2020.04163.CEECIND (C.R.) and CEECINST/00102/2018 Institutional Call (S.A.C.C.). This study forms part of the Advanced Materials program and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by the Basque Government under the IKUR program. Funding from the Basque Government Industry Department under the ELKARTEK program is also acknowledged. The authors thank CEMUP for the assistance with XPS analyses. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.Flexible and conformable conductive composites have been developed using different polymers, including water-based polyvinylpyrrolidone (PVP), chemical-resistant polyvinylidene fluoride (PVDF), and elastomeric styrene-ethylene-butylene-styrene (SEBS) reinforced with nitrogen-doped reduced graphene oxide with suitable viscosity in composites for printable solutions with functional properties. Manufactured by screen-printing using low-toxicity solvents, leading to more environmentally friendly conductive materials, the materials present an enormous step toward functional devices. The materials were enhanced in terms of filler/binder ratio, achieving screen-printed films with a sheet resistance lower than Rsq < 100 Ω/sq. The materials are biocompatible and support bending deformations up to 10 mm with piezoresistive performance for the different polymers up to 100 bending cycles. The piezoresistive performance of the SEBS binder is greater than double that the other composites, with a gauge factor near 4. Thermoforming was applied to all materials, with the PVP-based ones showing the lowest electrical resistance after the bending process. These conductive materials open a path for developing sustainable and functional devices for printable and conformable electronics.publishersversionpublishe

Fiber-Reinforced Polyester Composites with Photoluminescence Sensing Capabilities for UV Degradation Monitoring

The wide application of fiber-reinforced polymer composite (FRPC) materials has given rise to the problem of their durability and performance over time. These problems are largely associated with their environmental conditions and service procedures, including ultraviolet (UV) irradiation. Here, we propose the production of polyester-based composites with different contents of synthesized Y3Al5O12:Ce3+,Ga (YAG:Ce,Ga) particles to provide sensing abilities towards material degradation. In this regard, the composites were subjected to UV radiation exposure, and its influence on the morphological, mechanical, and optical properties of the materials was investigated. Our findings reveal the self-sensing capabilities of the developed FRPC. The results indicate the potential of the system for the development of highly effective coatings allowing to detect and monitor UV degradation in composite materials for demanding applications

Silica nanoparticles surface charge modulation of the electroactive phase content and physical-chemical properties of poly(vinylidene fluoride) nanocomposites

Composites based on a piezoelectric polymer (PVDF) doped with different silica nanoparticles (SiNPs) content (8, 16 and 32wt%) and functionalization (WF-without, NF-negative and PF-positive) have been investigated. Composite films were prepared by solvent casting and melt crystallization to investigate the effect of the presence of the SiNPs on the physico-chemical characteristics and, in particular, in the nucleation of the electroactive -phase of the polymer. It is shown that the introduction of the SiNPs allows to increase water surface angle up to 34% with respect to -PVDF, as well to increase the elastic modulus. Filler content and type have an important effect on the nucleation of the electroactive beta phase content and the dielectric properties of the composites, the larger values of both being obtained for positively surface charged nanoparticles. It is concluded that, taken into consideration the overall properties of the composites, the SiNPs-PF/PVDF nanocomposites with 8wt% filler content offer a promising approach for applications due to the improvement of the electroactive phase of PVDF.We thank Dr. Tania Ribeiro and Dr. Ana Sofia Rodrigues for technical assistance in the nanoparticle synthesis. This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of projects PTDC/CTM-CTM/32444/2017 and UID/NAN/50024/2019. The authors thank the FCT also for funding in the framework of the Strategic Programs UID/FIS/04650/2019 and projects LungChek ENMed/0049/2016, PTDC/EMD-EMD/28159/2017 and PTDC/BTM-MAT/28237/2017. SR and DC thank FCT for the grants SFRH/BD/111478/2015 and SFRH/BPD/121526/2016, respectively. Finally, the authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs, respectively.info:eu-repo/semantics/publishedVersio

Piezoelectric biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) based electrospun fiber mats with tailored porosity

Piezoelectric polymers allow transducing a mechanical stimulus into an electrical voltage, and vice-versa, leading to a large variety of sensor and actuator applications. Further, biodegradable platforms are increasingly needed in the environmental and biotechnological areas. In this context, this work reports on electrospun fiber based membranes with tailored physical properties and morphology, through the combination of the piezoelectric and biodegradable poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) polymer with poly(ethylene oxide) (PEO). The use of a binary polymer mixture and a binary solvent system of chloroform and dimethylformamide allows these materials to have their external and internal morphologies tailored. The porosity of the neat and blend fibers ranges between 79 and 93%. The produced materials demonstrated huge potential for environmental and biotechnological applications that require piezoelectricity, biodegradability and porosity.This work was supported by national funds through the Fundação para a Ciência e Tecnologia (FCT) and by ERDF through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) in the framework of the Strategic Programs UID/FIS/04650/2020 and project PTDC/BTM-MAT/28237/2017. The authors thank FCT for the research grant: SFRH/BD/141136/2018 (TMA), SFRH/BD /145345/2019 (LCF), and SFRH/BPD/121526/2016 (DMC), and CR thanks the FCT for the contract under the Stimulus of Scientific Employment, Individual Support (CEECIND) – 3rd Edition (2020.04163.CEECIND). Finally, the authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program