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"Lopes, N"
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The distillation and volatility of ionic liquids
by
Rebelo, Luís P.N.
,
Esperança, José M.S.S.
,
Gilea, Manuela A.
in
Chemistry
,
Composite materials
,
Decomposition
2006
Distilling the undistillable
Interest in ionic liquids has grown in line with their use as solvents in ‘green’ chemistry, which aims to avoid the use or production of hazardous substances during chemical processes. Ionic liquids are salts that are liquid at or close to room temperature. It has been widely assumed — but not proven — that they will decompose before they boil, so they are generally considered undistillable, and hence very difficult to purify. This now turns out to be incorrect: at low pressures and moderate temperatures, certain classes of ionic liquids have now been distilled without decomposition. As well as the intrinsic importance of this observation, it serves as a reminder that a ‘widely held assumption’ does not constitute proof: always obtain experimental verification.
It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled
1
,
2
. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived as non-volatile substances. During the last decade, interest in the field of ionic liquids has burgeoned
3
, producing a wealth of intellectual and technological challenges and opportunities for the production of new chemical and extractive processes
4
,
5
,
6
, fuel cells and batteries
7
, and new composite materials
8
,
9
. Much of this potential is underpinned by their presumed involatility. This characteristic, however, can severely restrict the attainability of high purity levels for ionic liquids (when they contain poorly volatile components) in recycling schemes, as well as excluding their use in gas-phase processes. We anticipate that our demonstration that some selected families of commonly used aprotic ionic liquids can be distilled at 200–300 °C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.
Journal Article
A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: prevalence, severity and impact on quality of life
by
Vissink, A.
,
Lopes, N. N. F.
,
Spijkervet, F. K. L.
in
Antimitotic agents
,
Antineoplastic agents
,
Body fluids
2010
Purpose
This systematic review aimed to assess the literature for prevalence, severity, and impact on quality of life of salivary gland hypofunction and xerostomia induced by cancer therapies.
Methods
The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. Two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results and conclusions for each article.
Results
The inclusion criteria were met by 184 articles covering salivary gland hypofunction and xerostomia induced by conventional, 3D conformal radiotherapy or intensity-modulated radiotherapy in head and neck cancer patients, cancer chemotherapy, total body irradiation/hematopoietic stem cell transplantation, radioactive iodine treatment, and immunotherapy.
Conclusions
Salivary gland hypofunction and xerostomia are induced by radiotherapy in the head and neck region depending on the cumulative radiation dose to the gland tissue. Treatment focus should be on optimized/new approaches to further reduce the dose to the parotids, and particularly submandibular and minor salivary glands, as these glands are major contributors to moistening of oral tissues. Other cancer treatments also induce salivary gland hypofunction, although to a lesser severity, and in the case of chemotherapy and immunotherapy, the adverse effect is temporary. Fields of sparse literature included pediatric cancer populations, cancer chemotherapy, radioactive iodine treatment, total body irradiation/hematopoietic stem cell transplantation, and immunotherapy.
Journal Article
Ionic Liquids and Water: Hydrophobicity vs. Hydrophilicity
by
Shimizu, Karina
,
Rodrigues, Rita F.
,
Freitas, Adilson A.
in
Alcohol
,
aqueous solutions
,
Hydrocarbons
2021
Many chemical processes rely extensively on organic solvents posing safety and environmental concerns. For a successful transfer of some of those chemical processes and reactions to aqueous media, agents acting as solubilizers, or phase-modifiers, are of central importance. In the present work, the structure of aqueous solutions of several ionic liquid systems capable of forming multiple solubilizing environments were modeled by molecular dynamics simulations. The effect of small aliphatic chains on solutions of hydrophobic 1-alkyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide ionic liquids (with alkyl = propyl [C3C1im][NTf2], butyl [C4C1im][NTf2] and isobutyl [iC4C1im][NTf2]) are covered first. Next, we focus on the interactions of sulphonate- and carboxylate-based anions with different hydrogenated and perfluorinated alkyl side chains in solutions of [C2C1im][CnF2n+1SO3], [C2C1im][CnH2n+1SO3], [C2C1im][CF3CO2] and [C2C1im][CH3CO2] (n = 1, 4, 8). The last system considered is an ionic liquid completely miscible with water that combines the cation N-methyl-N,N,N-tris(2-hydroxyethyl)ammonium [N1 2OH 2OH 2OH]+, with high hydrogen-bonding capability, and the hydrophobic anion [NTf2]–. The interplay between short- and long-range interactions, clustering of alkyl and perfluoroalkyl tails, and hydrogen bonding enables a wealth of possibilities in tailoring an ionic liquid solution according to the needs.
Journal Article
Multiple species animal movements: network properties, disease dynamics and the impact of targeted control actions
by
Sykes, Abagael L.
,
Machado, Gustavo
,
Lopes, Francisco P. N.
in
Analysis
,
Animal Husbandry - methods
,
Animals
2022
Infectious diseases in livestock are well-known to infect multiple hosts and persist through a combination of within- and between-host transmission pathways. Uncertainty remains about the epidemic dynamics of diseases being introduced on farms with more than one susceptible host species. Here, we describe multi-host contact networks and elucidate the potential of disease spread through farms with multiple hosts. Four years of between-farm animal movement among all farms of a Brazilian state were described through a static and monthly snapshot of network representations. We developed a stochastic multilevel model to simulate scenarios in which infection was seeded into single host and multi-host farms to quantify disease spread potential, and simulate network-based control actions used to evaluate the reduction of secondarily infected farms. We showed that the swine network was more connected than cattle and small ruminants in both the static and monthly snapshots. The small ruminant network was highly fragmented, however, contributed to interconnecting farms, with other hosts acting as intermediaries throughout the networks. When a single host was initially infected, secondary infections were observed across farms with all other species. Our stochastic multi-host model demonstrated that targeting the top 3.25% of the farms ranked by degree reduced the number of secondarily infected farms. The results of the simulation highlight the importance of considering multi-host dynamics and contact networks while designing surveillance and preparedness control strategies against pathogens known to infect multiple species.
Journal Article
A highly accurate methodology for the prediction and correlation of mechanical properties based on the slimness ratio of additively manufactured tensile test specimens
by
Moura, Lucas S
,
Vittoria, Gianfranco D
,
Fonseca, Eduardo B
in
Additive manufacturing
,
Axial stress
,
Computer simulation
2020
Additive manufacturing has been established as a process to produce structural and load-bearing parts, and this process has become attractive to many industries such as medical, aerospace, automotive, and oil and gas. These industrial applications are commonly characterized by high and stringent regulatory requirements. Due to the disparity and lack of consensus in mechanical properties reported in the literature, and the need to test and validate the components manufactured by the additive manufacturing process, this work aimed at performing an experimental simulation study of the effects of the slimness ratio on the mechanical properties of as-built Ti–6Al–4V electron beam additively manufactured parts subjected to tensile tests. From the obtained results, we propose an accurate method for the prediction and correlation of mechanical properties of specimens with different geometries. The main conclusion from this study is that elongation at fracture and tensile toughness follow a logarithmic equation and that symmetric cross-section specimens show superior mechanical strength with similar mechanical behavior to high-stress-triaxiality parts subjected to tensile tests. The fracture mode and associated micromechanisms are strongly influenced by the specimen’s width/thickness ratio, and the use of the Bertella–Oliver equation coupled with finite element method (analysis) tools was effective toward understanding the mechanical behavior of specimens subjected to tensile tests. In summary, the method presented here may be useful for predicting and comparing the data of specimens that do not comply with normative values.
Journal Article
Economic aspects of the deployment of fusion energy: the valley of death and the innovation cycle
2019
The speed at which fusion energy can be deployed is considered. Several economical factors are identified that impede this speed. Most importantly, the combination of an unprecedentedly high investment level needed for the proof of principle and the relatively long construction time of fusion plants precludes an effective innovation cycle. The valley of death is discussed, i.e. the period when a large investment is needed for the construction of early generations of fusion reactors, when there is no return yet. It is concluded that, within the mainstream scenario—a few DEMO reactors towards 2060 followed by generations of relatively large reactors—there is no realistic path to an appreciable contribution to the energy mix in the twenty-first century if economic constraints are applied. In other words, fusion will not contribute to the energy transition in the time frame of the Paris climate agreement. Within the frame of this analysis, the development of smaller, cheaper and most importantly, fast-to-build fusion plants could possibly represent an option to accelerate the introduction of fusion power. Whether this is possible is a technical question that is outside the scope of this paper, but this question is addressed in other contributions to the Royal Society workshop. This article is part of a discussion meeting issue ‘Fusion energy using tokamaks: can development be accelerated?’.
Journal Article
Extracellular matrix-derived and low-cost proteins to improve polyurethane-based scaffolds for vascular grafts
2022
Vascular graft surgeries are often conducted in trauma cases, which has increased the demand for scaffolds with good biocompatibility profiles. Biodegradable scaffolds resembling the extracellular matrix (ECM) of blood vessels are promising vascular graft materials. In the present study, polyurethane (PU) was blended with ECM proteins collagen and elastin (Col-El) and gelatin (Gel) to produce fibrous scaffolds by using the rotary jet spinning (RJS) technique, and their effects on in vitro properties were evaluated. Morphological and structural characterization of the scaffolds was performed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Micrometric fibers with nanometric rugosity were obtained. Col-El and Gel reduced the mechanical strength and increased the hydrophilicity and degradation rates of PU. No platelet adhesion or activation was observed. The addition of proteins to the PU blend increased the viability, adhesion, and proliferation of human umbilical vein endothelial cells (HUVECs). Therefore, PU-Col-El and PU-Gel scaffolds are promising biomaterials for vascular graft applications.
Journal Article
Self-guided propagation of laser pulses reflected at high intensity from plasma mirrors
2025
The reflectivity and optical quality of laser pulses reflected off 125μm Kapton™ tape was investigated for use as a repeatable plasma mirror. Reflectivities of around 70% were measured at ≈2 × 10 21Wm−2 while maintaining the quality of the laser beam. The ability of the reflected pulse to drive a laser wakefield accelerator was investigated. Self-guided propagation of the reflected beam through a gas cell was observed and shown to depend on the plasma density. Particle-in-cell simulations showed that a wakefield would have been generated, driven solely by the energy within the central high intensity feature of the focal spot. The use of plasma mirrors at these elevated intensities would open up the possibilities of extremely compact configurations for laser wakefield accelerator stages.
Journal Article
Genome-Wide Association Studies and QTL Mapping Reveal a New Locus Associated with Resistance to Bacterial Pustule Caused by Xanthomonas citri pv. glycines in Soybean
by
Arias, Carlos Arrabal
,
Silva, Danielle Cristina Gregório da
,
Abdelnoor, Ricardo Vilela
in
Analysis
,
Bacteria
,
Chromosome 17
2024
Bacterial pustule (BP), caused by Xanthomonas citri pv. glycines, is an important disease that, under favorable conditions, can drastically affect soybean production. We performed a genome-wide association study (GWAS) with a panel containing Brazilian and American cultivars, which were screened qualitatively and quantitatively against two Brazilian X. citri isolates (IBS 333 and IBS 327). The panel was genotyped using a genotyping by sequencing (GBS) approach, and we identified two main new regions in soybeans associated with X. citri resistance on chromosomes 6 (IBS 333) and 18 (IBS 327), different from the traditional rxp gene located on chromosome 17. The region on chromosome 6 was also detected by QTL mapping using a biparental cross between Williams 82 (R) and PI 416937 (S), showing that Williams 82 has another recessive resistance gene besides rxp, which was also detected in nine BP-resistant ancestors of the Brazilian cultivars (including CNS, S-100), based on haplotype analysis. Furthermore, we identified additional SNPs in strong LD (0.8) with peak SNPs by exploring variation available in WGS (whole genome sequencing) data among 31 soybean accessions. In these regions in strong LD, two candidate resistance genes were identified (Glyma.06g311000 and Glyma.18g025100) for chromosomes 6 and 18, respectively. Therefore, our results allowed the identification of new chromosomal regions in soybeans associated with BP disease, which could be useful for marker-assisted selection and will enable a reduction in time and cost for the development of resistant cultivars.
Journal Article
Ultrafast Imaging of Laser Driven Shock Waves using Betatron X-rays from a Laser Wakefield Accelerator
2018
Betatron radiation from laser wakefield accelerators is an ultrashort pulsed source of hard, synchrotron-like x-ray radiation. It emanates from a centimetre scale plasma accelerator producing GeV level electron beams. In recent years betatron radiation has been developed as a unique source capable of producing high resolution x-ray images in compact geometries. However, until now, the short pulse nature of this radiation has not been exploited. This report details the first experiment to utilize betatron radiation to image a rapidly evolving phenomenon by using it to radiograph a laser driven shock wave in a silicon target. The spatial resolution of the image is comparable to what has been achieved in similar experiments at conventional synchrotron light sources. The intrinsic temporal resolution of betatron radiation is below 100 fs, indicating that significantly faster processes could be probed in future without compromising spatial resolution. Quantitative measurements of the shock velocity and material density were made from the radiographs recorded during shock compression and were consistent with the established shock response of silicon, as determined with traditional velocimetry approaches. This suggests that future compact betatron imaging beamlines could be useful in the imaging and diagnosis of high-energy-density physics experiments.
Journal Article