Scattering studies of the size and structure of cellulose dissolved in aqueous hydroxide base solvents

Combining NaOH with other hydroxide bases with superior dissolution properties can be a means of improving dissolution of cellulose. However, this raises questions about how the size and structure of cellulose vary when dissolved in different hydroxide bases. Here, cellulose in aqueous solutions of NaOH, Tetramethylammonium hydroxide (TMAH), Benzyltrimethylammonium hydroxide (Triton B) and previously studied equimolar solutions of NaOH/TMAH and NaOH/Triton B were investigated using small angle X-ray scattering, static and dynamic light scattering. The results show that cellulose in NaOH(aq) is largely aggregated and that the more hydrophobic TMAH and Triton are capable of molecularly dissolving cellulose into worm-like conformations, stiffer than in NaOH. The dissolution properties of mixtures are highly dependent on the compatibility of the individual bases; in line with previous observations of the properties of the solutions which now could be correlated to the structure of the cellulose on a nano- and microscale

Evaluation of composition and mineral structure of callus tissue in rat femoral fracture.

ABSTRACT. Callus formation is a critical step for successful fracture healing. Little is known about the molecular composition and mineral structure of the newly formed tissue in the callus. The aim was to evaluate the feasibility of small angle x-ray scattering (SAXS) to assess mineral structure of callus and cortical bone and if it could provide complementary information with the compositional analyses from Fourier transform infrared (FTIR) microspectroscopy. Femurs of 12 male Sprague-Dawley rats at 9 weeks of age were fractured and fixed with an intramedullary 1.1 mm K-wire. Fractures were treated with the combinations of bone morphogenetic protein-7 and/or zoledronate. Rats were sacrificed after 6 weeks and both femurs were prepared for FTIR and SAXS analysis. Significant differences were found in the molecular composition and mineral structure between the fracture callus, fracture cortex, and control cortex. The degree of mineralization, collagen maturity, and degree of orientation of the mineral plates were lower in the callus tissue than in the cortices. The results indicate the feasibility of SAXS in the investigation of mineral structure of bone fracture callus and provide complementary information with the composition analyzed with FTIR. Moreover, this study contributes to the limited FTIR and SAXS data in the field

Structure and dynamics of highly concentrated LiTFSI/acetonitrile electrolytes

High salt concentration has been shown to induce increased electrochemical stability in organic solvent-based electrolytes. Accompanying the change in bulk properties is a structural ordering on mesoscopic length scales and changes in the ion transport mechanism have also been suggested. Here we investigate the local structure and dynamics in highly concentrated acetonitrile electrolytes as a function of salt concentration. Already at low concentrations ordering on microscopic length scales in the electrolytes is revealed by small angle X-ray scattering, as a result of correlations of Li+ coordinating clusters. For higher salt concentrations a charge alternation-like ordering is found as anions start to take part in the solvation. Results from quasi-elastic neutron spectroscopy reveal a jump diffusion dynamical process with jump lengths virtually independent of both temperature and Li-salt concentration. The jump can be envisaged as dissociation of a solvent molecule or anion from a particular Li+ solvation structure. The residence time, 50-800 ps, between the jumps is found to be highly temperature and Li-salt concentration dependent, with shorter residence times for higher temperature and lower concentrations. The increased residence time at high Li-salt concentration can be attributed to changes in the interaction of the solvation shell as a larger fraction of TFSI anions take part in the solvation, forming more stable solvation shells

Co-creation, innovation, decision-making, tech-transfer, and sustainability actions

Funding Information: Open access funding provided by FCT|FCCN (b-on). This work was funded by the European Union’s Horizon 2020 program [H2020-SC5-2019–2]—869520 NextLand, [H2020-SPACE-202]—101004362 NextOcean, Fundação para a Ciência e a Tecnologia (UIDB/00124/2020 and Social Sciences DataLab, PINFRA/22209/2016), POR Lisboa and POR Norte (Social Sciences DataLab, PINFRA/22209/2016). Publisher Copyright: © 2023, The Author(s).European Community (EC) Horizon-funded projects and Earth Observation-based Consortia aim to create sustainable value for Space, Land, and Oceans. They typically focus on addressing Sustainable Development Goals (SDGs). Many of these projects (e.g. Commercialization and Innovation Actions) have an ambitious challenge to ensure that partners share core competencies to simultaneously achieve technological and commercial success and sustainability after the end of the EC funds. To achieve this ambitious challenge, Horizon projects must have a proper governance model and a systematized process that can manage the existing paradoxical tensions involving numerous European partners and their respective agendas and stakeholders. This article presents the VCW-Value Creation Wheel (Lages in J Bus Res 69: 4849–4855, 2016), as a framework that has its roots back in 1995 and has been used since 2015 in the context of numerous Space Business, Earth Observation, and European Community (EC) projects, to address complex problems and paradoxical tensions. In this article, we discuss six of these paradoxical tensions that large Horizon Consortia face in commercialization, namely when managing innovation ecosystems, co-creating, taking digitalization, decision-making, tech-transfer, and sustainability actions. We discuss and evaluate how alliance partners could find the optimal balance between (1) cooperation, competition, and coopetition perspectives; (2) financial, environmental, and social value creation; (3) tech-push and market-pull orientations; (4) global and local market solutions; (5) functionality driven and human-centered design (UX/UI); (6) centralized and decentralized online store approaches. We discuss these challenges within the case of the EC H2020 NextLand project answering the call for greening the economy in line with the Sustainable Development Goals (SDGs). We analyze NextLand Online Store, and its Business and Innovation Ecosystem while considering the input of its different stakeholders, such as NextLand’s commercial team, service providers, users, advisors, EC referees, and internal and external stakeholders. Preliminary insights from a twin project in the field of Blue Economy (EC H2020 NextOcean), are also used to support our arguments. Partners, referees, and EC officers should address the tensions mentioned in this article during the referee and approval processes in the pre-grant and post-grant agreement stages. Moreover, we propose using the Value Creation Wheel (VCW) method and the VCW meta-framework as a systematized process that allows us to co-create and manage the innovation ecosystem while engaging all the stakeholders and presenting solutions to address these tensions. The article concludes with theoretical implications and limitations, managerial and public policy implications, and lessons for Horizon Europe, earth observation, remote sensing, and space business projects.publishersversionpublishe

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Mesoscale ordering in binary aqueous solvents induced by ion size asymmetry

Surprising weak assembly behavior has lately been found in binary aqueous solvents containing antagonistic salt. The underlying mechanism is still under debate, particularly the role of ion size asymmetry. Here we use small-angle X-ray scattering to study the effect of ion size asymmetry on the mesoscale ordering in a binary solvent composed of water and 2,6-dimethylpyridine with added symmetrical quaternary ammonium salt. By systematically elongating the hydrocarbon side-chain lengths, and hence developing cation-to-anion size asymmetry, we provide the first experimental evidence of a gradual build-up of the solvent's mesoscale ordering. These results are in qualitative agreement with model-independent theoretical predictions

Systematic Limitations in Concentration Analysis via Anomalous Small-Angle X-ray Scattering in the Small Structure Limit

Anomalous small angle scattering measurements have been applied to diluted solutions of anionic polyacrylates decorated by specifically-interacting Pb2+ cations, revealing partial collapse of the polyacrylate into pearl-like subdomains with a size on the order of a few nanometers. From the pure-resonant scattering contribution of the Pb2+ cations, and from subsequent analysis of the resonant-invariant, the amount of Pb2+ cations condensed onto the polyanions with respect to the total amount of Pb2+ cations in the solvent was estimated. In order to scrutinize systematic limitations in the determination of the chemical concentrations of resonant scattering counterions in the collapsed phase, Monte Carlo simulations have been performed. The simulations are based on structural confinements at variable size in the range of few nanometers, which represent the collapsed subdomains in the polyanions. These confinements were gradually filled to a high degree of the volume fraction with resonant scattering counterions giving access to a resonant-invariant at a variable degree of filling. The simulations revealed in the limit of small structures a significant underestimation of the true degree of filling of the collapsed subdomains when determining chemical concentrations of Pb2+ cations from the resonant invarian

SAXS and ASAXS on Dilute Sodium Polyacrylate Chains Decorated with Lead Ions

Bivalent lead ions as representative main group heavy metal cations form specific interactions with the negatively charged COO residues of sodium polyacrylate chains in dilute aqueous solution. The interactions eventually lead to aggregation and precipitation of sodium polyacrylate chains partially neutralized with Pb2 cations. The present work outlines a small angle X ray SAXS and light scattering study of the polyacrylate chains undergoing changes in coil conformation and successive aggregation while approaching and crossing the Pb2 induced precipitation threshold. The study reveals a coil shrinking while approaching the precipitation threshold. Anomalous SAXS ASAXS complemented this information with a first insight into the spatial distribution of the Pb2 cations captured by the polyacrylate chains together with a semi quantitative estimation of the amount of Pb2 cations located within the collapsed domains of the shrinking chains. Conformational aspects of the shrinking coils could be established by means of model form factors of hybrid chains formed by a freely jointed chain of rods with spheres located on all or part of the joints. Development and application of the form factors of the pearl necklace like hybrid model chains and the use of quantitative analysis of ASAXS data are described and discussed in detai

SAXS and ASAXS on Dilute Sodium Polyacrylate Chains Decorated with Lead Ions

Bivalent lead ions as representative main group heavy metal cations form specific interactions with the negatively charged COO^– residues of sodium polyacrylate chains in dilute aqueous solution. The interactions eventually lead to aggregation and precipitation of sodium polyacrylate chains partially neutralized with Pb²⁺ cations. The present work outlines a small-angle X-ray (SAXS) and light scattering study of the polyacrylate chains undergoing changes in coil conformation and successive aggregation while approaching and crossing the Pb²⁺-induced precipitation threshold. The study reveals a coil shrinking while approaching the precipitation threshold. Anomalous SAXS (ASAXS) complemented this information with a first insight into the spatial distribution of the Pb²⁺ cations captured by the polyacrylate chains together with a semiquantitative estimation of the amount of Pb²⁺ cations located within the collapsed domains of the shrinking chains. Conformational aspects of the shrinking coils could be established by means of model form factors of hybrid chains formed by a freely jointed chain of rods with spheres located on all or part of the joints. Development and application of the form factors of the pearl-necklace-like hybrid model chains and the use of quantitative analysis of ASAXS data are described and discussed in detail

Towards smart self-assembly of colloidal silica particles through diblock copolymer crystallization

An innovative associative strategy, crystallization-driven self-assembly, is discussed for hybrid inorganicorganic materials. We report the use of a semicrystalline poly(butadiene)-b-poly(ethylene oxide)(PB-b-PEO) diblock copolymer (BCP) that self-assembles with silica nanoparticles (NPs) in a selective solvent. In ethanol, at 60 degrees C, that is above the melting temperature T-m of the PEO block, the BCP forms amorphous spherical micelles consisting of a liquid PEO-corona and a core of PB-chains. The controlled formation of hybrid structures is achieved using temperature quenches below T-m of the BCP where the PEO block crystallizes in the micellar corona, leading to the formation of lamellar structures. The crystallization further dictates the spatial distribution and drives the self-assembly of the colloidal particles into the BCP lamellar domains. Such association is tunable and reversible, following the crystallization temperature T. The employed method offers new perspectives for the directed self-assembly of colloidal particles through an underlying controlled crystallization process of semicrystalline BCP in solution. (C) 2013 Elsevier Ltd. All rights reserved