Impact of Glucose on the Nanostructure and Mechanical Properties of Calcium-Alginate Hydrogels

Alginate is a polysaccharide obtained from brown seaweed that is widely used in food, pharmaceutical, and biotechnological applications due to its versatility as a viscosifier and gelling agent. Here, we investigated the influence of the addition of glucose on the structure and mechanical properties of alginate solutions and calcium-alginate hydrogels produced by internal gelation through crosslinking with Ca2+ . Using1H low-field nuclear magnetic resonance (NMR) and small angle neutron scattering (SANS), we showed that alginate solutions at 1 wt % present structural hetero-geneities at local scale whose size increases with glucose concentration (15–45 wt %). Remarkably, the molecular conformation of alginate in the gels obtained from internal gelation by Ca2+ crosslinking is similar to that found in solution. The mechanical properties of the gels evidence an increase in gel strength and elasticity upon the addition of glucose. The fitting of mechanical properties to a poroelastic model shows that structural changes within solutions prior to gelation and the increase in solvent viscosity contribute to the gel strength. The nanostructure of the gels (at local scale, i.e., up to few hundreds of \uc5) remains unaltered by the presence of glucose up to 30 wt %. At 45 wt %, the permeability obtained by the poroelastic model decreases, and the Young’s modulus increases. We suggest that macro (rather than micro) structural changes lead to this behavior due to the creation of a network of denser zones of chains at 45 wt % glucose. Our study paves the way for the design of calcium-alginate hydrogels with controlled structure for food and pharmaceutical applications in which interactions with glucose are of relevance

A data-mining approach to understanding the impact of multi-doping on the ionic transport mechanism of solid electrolytes materials : the case of dual-doped Ga0.15/Scy Li7La3Zr2O12

Authors acknowledge financial support by the Ministerio de Economía y Competitividad (MICINN) of the Spanish Government through BCAM Severo Ochoa accreditation CEX2021-001142-S, PID2019-104927GB-C22, PID2022-136585NB-C22 grants and “PLAN COMPLEMENTARIO MATERIALES AVANZADOS 2022-2025”, PROYECTO No. 1101288 [ELKARTEK ICME]. This work was supported by the BERC 2022-2025 Program, by ELKARTEK Programme, grants KK-2022/00006, KK-2023/00017 and by IKUR Programme funded by the Basque Government. This work has been possible thanks to the computing infrastructure of the i2BASQUE academic network, DIPC Computer Center, RES BSC (QHS-2022-3-0027), and the technical and human support provided by IZO-SGI SGIker of UPV/EHU. The work has been performed under the Project HPC-EUROPA3 (INFRAIA-2016-1-730897), with the support of the EC Research Innovation Action under the H2020 Programme; in particular, H. A. C. gratefully acknowledges the support of the School of Chemistry, University of St. Andrews, and the computer resources (ARCHER2) and technical support provided by EPCC.This study presents novel computational methods applied to the technologically significant solid electrolyte materials, Li6.55+yGa0.15La3Zr2−yScyO12 (Ga0.15/Scy-LLZO), in order to investigate the effect of the distribution of Ga3+ on Li-ion dynamics. Utilizing a specifically designed first-principles-based force field, molecular dynamics, and advanced hybrid Monte Carlo simulations, we systematically examine the material's transport properties for a range of Ga3+ and Sc3+ cationic concentrations. Additionally, we introduce innovative post-processing methods employing data mining clustering techniques, shedding light on Li+ ion behavior and conductivity mechanisms. Contrary to prior assumptions, the presence of Ga3+ in octahedral sites, not tetrahedral junctions, optimally enhances Li-ion conductivity, unlocking Li-ion diffusion pathways. The research illuminates how dopant distribution influences Li+ site occupancy and conductivity, offering key insights for advanced solid electrolyte design.Peer reviewe

Probing adhesion between nanoscale cellulose fibres using AFM lateral force spectroscopy: the effect of hemicelluloses on hydrogen bonding

Inter-fibre adhesion is a key contributing factor to the mechanical response and functionality of cellulose-based biomaterials. ‘Dip-and-Drag’ lateral force atomic force microscopy technique is used here to evaluate the influence of arabinoxylan and xyloglucan on interactions between nanoscale cellulose fibres within a hydrated network of bacterial cellulose. A cohesive zone model of the detachment event between two nano-fibres is used to interpret the experimental data and evaluate inter-fibre adhesion energy. The presence of xyloglucan or arabinoxylan is found to increase the adhesive energy by a factor of 4.3 and 1.3, respectively, which is consistent with these two hemicellulose polysaccharides having different specificity of hydrogen bonding with cellulose. Importantly, xyloglucan's ability to strengthen adhesion between cellulose nano-fibres supports emergent models of the primary plant cell walls (Park & Cosgrove, 2012b), which suggest that xyloglucan chains confined within cellulose-cellulose junctions play a key role in cell wall's mechanical response

Cellulose-pectin composite hydrogels: intermolecular interactions and material properties depend on order of assembly

Plant cell walls have a unique combination of strength and flexibility however, further investigations are required to understand how those properties arise from the assembly of the relevant biopolymers. Recent studies indicate that Ca2+-pectates can act as load-bearing components in cell walls. To investigate this proposed role of pectins, bioinspired wall models were synthesised based on bacterial cellulose containing pectin-calcium gels by varying the order of assembly of cellulose/pectin networks, pectin degree of methylesterification and calcium concentration. Hydrogels in which pectin-calcium assembly occurred prior to cellulose synthesis showed evidence for direct cellulose/pectin interactions from small angle scattering (SAXS and SANS), had the densest networks and the lowest normal stress. The strength of the pectin-calcium gel affected cellulose structure, crystallinity and material properties. The results highlight the importance of the order of assembly on the properties of cellulose composite networks and support the role of pectin in the mechanics of cell walls. (C) 2017 Elsevier Ltd. All rights reserved

Narrativas de posconflicto y pedagogía para la paz

La construcción colectiva de la memoria es un tema de larga trayectoria en Colombia, incluso desde mucho antes de la firma del tratado de paz con la extinta guerrilla de las FARC. No obstante, el presente proyecto de investigación parte de la experiencia propia del posconflicto entre dicha guerrilla y el Estado junto con la posibilidad de lograr esa anhelada “gran paz” en Colombia. Teniendo en cuenta lo estipulado en el informe final redactado por la comisión para la verdad, asimismo, los “imperativos” trazados desde políticas educativas nacionales: ¿cómo las apuestas planteadas en el documento redefinen/reorientan los procesos formativos en Colombia de cara a la construcción de “un nuevo país”? En este orden de ideas, nuestras preguntas de investigación serán las siguientes: ¿cuál es el aporte real de las ciencias sociales en los procesos de transformación social por los que apuesta el proyecto político nacional? ¿De qué modo las reflexiones disciplinares previas respecto de la construcción colectiva de la memoria, justicia social, verdad aportan (en sentido práctico) a la construcción de “la gran paz” en diferentes contextos educativos (formales y no formales)?Universidad Libre - Facultad de Ciencias de la Educación - Español y Lenguas Extranjeras/Educación Infanti

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at root s=5.02 TeV Using Leptonic Decays

The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy