SwePub - search: L773:2397 2106

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1.	Corbett, Thomas, et al. (author) Organic carbon source controlled microbial olivine dissolution in small-scale flow-through bioreactors, for CO2 removal 2024 In: NPJ MATERIALS DEGRADATION. - : Nature Publishing Group. - 2397-2106. ; 8:1 Journal article (peer-reviewed)abstract The development of carbon dioxide removal methods, coupled with decreased CO2 emissions, is fundamental to achieving the targets outlined in the Paris Agreement limiting global warming to 1.5 degrees C. Here we are investigating the importance of the organic carbon feedstock to support silicate mineral weathering in small-scale flow through bioreactors and subsequent CO2 sequestration. Here, we combine two bacteria and two fungi, widely reported for their weathering potential, in simple flow through bioreactors (columns) consisting of forsterite and widely available, cheap organic carbon sources (wheat straw, bio-waste digestate of pig manure and biowaste, and manure compost), over six weeks. Compared to their corresponding abiotic controls, the inoculated straw and digestate columns release more total alkalinity (similar to 2 times more) and produce greater dissolved and solid inorganic carbon (29% for straw and 13% for digestate), suggesting an increase in CO2 sequestration because of bio-enhanced silicate weathering. Microbial biomass is higher in the straw columns compared to the digestate and manure compost columns, with a phospholipid fatty acid derived total microbial biomass 10 x greater than the other biotic columns. Scanning Electron Microscopy imaging shows the most extensive colonisation and biofilm formation on the mineral surfaces in the straw columns. The biotic straw and digestate columns sequester 50 and 14 mg C more than their abiotic controls respectively, while there is no difference in the manure columns. The selection of organic carbon sources to support microbial communities in the flow through bioreactors controlls the silicate weathering rates and CO2 sequestration.
2.	Esmaily, Mohsen, et al. (author) High-temperature oxidation behaviour of AlxFeCrCoNi and AlTiVCr compositionally complex alloys 2020 In: npj Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; 4:1 Journal article (peer-reviewed)abstract Compositionally complex alloys (CCAs), also termed as high entropy alloys (HEAs) or multi-principal element alloys (MPEAs), are being considered as a potential solution for many energy-related applications comprising extreme environments and temperatures. Herein, a review of the pertinent literature is performed in conjunction with original works characterising the oxidation behaviour of two diverse Al-containing alloys; namely a lightweight (5.06 g/cm(3)) single-phase AlTiVCr CCA and a multiple-phase Al0.9FeCrCoNi CCA (6.9 g/cm(3)). The thermogravimetric results obtained during oxidation of the alloys at 700 and 900 degrees C revealed that both alloys tended to obey the desired parabolic rate law. Post-exposure analysis by means of electron microscopy indicated that while the oxide scale formed on the AlTiVCr is adherent to the substrate, the scale developed on the Al0.9FeCrCoNi displays a notable spalling propensity. This study highlights the need for tailoring the protective properties of the oxide scale formed on the surface of the CCAs.
3.	Gout, Thomas L., et al. (author) Diffusive processes in aqueous glass dissolution 2019 In: npj Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; 3:1 Journal article (peer-reviewed)abstract High level nuclear waste is often immobilised in a borosilicate glass for disposal. However, this glass corrodes in contact with aqueous solutions. To predict radionuclide releases from wasteforms, their dissolution mechanisms must be understood. Understanding glass dissolution mechanisms presents a challenge across numerous other disciplines and many glass dissolution models still remain conflicted. Here we show that diffusion was a significant process during the later stages of dissolution of a simplified waste glass but was not evidenced during the initial stages of dissolution. The absence of measurable isotopic fractionation in solution initially supports models of congruent dissolution. However, the solution becoming isotopically lighter at later times evidences diffusive isotopic fractionation and opposes models that exclude diffusive transport as a significant mechanism. The periodically sampled isotopic methodologies outlined here provide an additional dimension with which to understand glass dissolution mechanisms beyond the usual measurement of solution concentrations and, post-process, nano-scale analysis of the altered glass.
4.	Hedberg, Yolanda, Docent, 1985- (author) Role of proteins in the degradation of relatively inert alloys in the human body 2018 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 2:1 Journal article (peer-reviewed)abstract Many biomedical materials used today for applications such as orthopedic, dental, and cardiovascular implants and devices are made of corrosion-resistant, 'inert', metallic materials of the cobalt-chromium, titanium, and stainless steel alloy groups. This perspective focuses on the role of proteins in the degradation of these materials in a human body environment. After adsorption, the proteins interact relatively slowly with the metal and metal surface oxide. A number of factors, including the individual body chemistry (especially the presence of inflammatory cells producing oxidative species), determine whether the proteins can bind to metals in the surface oxide and whether the metal-protein conjugates can detach from the surface. Metals in the forms of protein-bound metal ions or nanosized particles can also increase protein-protein interactions and aggregation, which can cause some health effects and change the material degradation mechanism. While proteins in some short-term studies (<6 h) even decrease material degradation due to shielding effects and better lubrication, they may increase degradation after longer time periods due to relatively slow binding, detachment, and combined corrosion processes. In-vitro material degradation studies of relatively corrosion-resistant alloys for biomedical applications should therefore include long-term studies, complexing agents or proteins, and realistic oxidative environments simulating inflammatory conditions.
5.	Larsson, Alfred, et al. (author) Dynamics of early-stage oxide formation on a Ni-Cr-Mo alloy 2024 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 8:1 Journal article (peer-reviewed)abstract Corrosion results in large costs and environmental impact but can be controlled by thin oxide films that passivate the metal surfaces and hinder further oxidation or dissolution in an aqueous environment. The structure, chemistry, and thickness of these oxide films play a significant role in determining their anti-corrosion properties and the early-stage oxidation dynamics affect the properties of the developed oxide. Here, we use in situ X-ray Photoelectron Spectroscopy (XPS) to study the early-stage oxidation of a Ni-Cr-Mo alloy at room temperature and up to 400 degrees C. Cr and Mo begin to oxidize immediately after exposure to O2, and Cr3+, Mo4+, and Mo6+ oxides are formed. In contrast, Ni does not contribute significantly to the oxide film. A self-limiting oxide thickness, which did not depend on temperature below 400 degrees C, is observed. This is attributed to the consumption of available Cr and Mo near the surface, which results in an enrichment of metallic Ni under the oxide. The self-limited oxide thickness is 6-8 angstrom, which corresponds to 3-4 atomic layers of cations in the oxide. At 400 degrees C, sublimation of Mo6+ oxide is observed, resulting in the formation of an almost pure layer of Cr2O3 on the alloy surface. Lastly, a mechanism is presented that explains the formation of the bi-layer oxide structure observed for Ni-Cr-Mo alloys, which involves the enhanced migration of hexavalent Mo ions in the electric field, which drives mass transport during oxidation according to both the Cabrera Mott model and the Point Defect Model.
6.	Li, Wenchao, et al. (author) Numerical simulation of carbon steel atmospheric corrosion under varying electrolyte-film thickness and corrosion product porosity 2023 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 7:1 Journal article (peer-reviewed)abstract A finite element model is developed to study dynamics of atmospheric corrosion of carbon steel, focusing on the influence of thin electrolyte film thickness under varying corrosion product porosity. Calculations have been done to evaluate the impact of electrolyte film thickness and corrosion product porosity on oxygen diffusion path, and the hindrance effect of corrosion products on the metal surface activity. The time evolution of corrosion current density and controlling steps in the corrosion process are explored. When the corrosion products are loose, oxygen diffusion is the dominant controlling step, and the thicker the electrolyte film, the lower the corrosion rate. When they are dense, the corrosion process is controlled by the mixture of oxygen diffusion and the surface discharge. The oxygen diffusion path is determined only by the corrosion product porosity, and therefore the corrosion rate is not affected by the electrolyte film thickness.
7.	Linder, Clara, et al. (author) Corrosion resistance of additively manufactured aluminium alloys for marine applications 2024 In: npj Materials Degradation. - : Springer. - 2397-2106. ; 8:1 Journal article (peer-reviewed)abstract Additive manufacturing opens new possibilities for designing light-weight structures using aluminium alloys. The microstructure of two Al alloys and their corrosion resistance in NaCl and natural seawater environments were investigated. The newly designed Al-Mn-Cr-Zr based alloy showed a higher corrosion resistance than reference AlSi10Mg alloy in both environments in as printed and heat-treated conditions. The corrosion initiated in the Al matrix along the precipitates in the alloys where the Volta potential difference was found the highest. The coarser microstructure and precipitate composition of the new Al-alloy led to the formation of a resistant passive film which extended the passivity region of the Al-Mn-Cr-Zr alloy compared to the AlSi10Mg alloy. The effect of heat treatment could be seen in the microstructure as more precipitates were found in between the melt pool boundaries, which affected the corrosion initiation and slightly the pitting resistance. Overall, this study shows that a newly designed Al-alloy for additive manufacturing has a suitable corrosion resistance for applications in marine environments.
8.	Långberg, Marie, 1988-, et al. (author) Redefining passivity breakdown of super duplex stainless steel by electrochemical operando synchrotron near surface X-ray analyses 2019 In: npj Materials Degradation. - Stockholm, : Springer Science and Business Media LLC. - 2397-2106. ; 3:1 Journal article (peer-reviewed)abstract Passivity determines corrosion resistance and stability of highly-alloyed stainless steels, and passivity breakdown is commonly believed to occur at a fixed potential due to formation and dissolution of Cr(VI) species. In this work, the study of a 25Cr–7Ni super duplex stainless steel in 1 M NaCl solution revealed that the passivity breakdown is a continuous degradation progress of the passive film over a potential range, associated with enhanced Fe dissolution before rapid Cr dissolution and removal of the oxide. The breakdown involves structural and compositional changes of the passive film and the underlying alloy surface layer, as well as selective metal dissolution depending on the anodic potential. The onset of passivity breakdown occurred at 1000 mV/Ag/AgCl, and Fe dissolved more on the ferrite than the austenite phase. With increasing potential, the passive film became thicker but less dense, while the underlying alloy surface layer became denser indicating Ni and Mo enrichment. Rapid Cr dissolution occurred at ≥1300 mV/Ag/AgCl.
9.	Nava-Farias, Lorena, et al. (author) Applying laboratory methods for durability assessment of vitrified material to archaeological samples 2021 In: npj Materials Degradation. - : Springer Nature. - 2397-2106. ; 5:1 Journal article (peer-reviewed)abstract Laboratory testing used to assess the long-term chemical durability of nuclear waste forms may not be applicable to disposal because the accelerated conditions may not represent disposal conditions. To address this, we examine the corrosion of vitrified archeological materials excavated from the near surface of a ~1500-year old Iron Age Swedish hillfort, Broborg, as an analog for the disposal of vitrified nuclear waste. We compare characterized site samples with corrosion characteristics generated by standard laboratory durability test methods including the product consistency test (PCT), the vapor hydration test (VHT), and the EPA Method 1313 test. Results show that the surficial layer of the Broborg samples resulting from VHT displays some similarities to the morphology of the surficial layer formed over longer timescales in the environment. This work provides improved understanding of long-term glass corrosion behavior in terms of the thickness, morphology, and chemistry of the surficial features that are formed.
10.	Pakharenko, Viktoriya, et al. (author) Chemical and molecular structure transformations in atomistic conformation of cellulose nanofibers under thermal environment 2022 In: npj Materials Degradation. - : Springer Nature. - 2397-2106. ; 6 Journal article (peer-reviewed)abstract The structural changes of the glucopyranose chain and the chemical compositional response of cellulose nanofibers (CNFs) under thermal exposure (at 190 °C for 5 h) have remained a significant gap in the understanding of the long-term performance of nanocellulose. Herein, CNF films with different chemical compositions were investigated to confirm the structural transformation of glucopyranose (coupling constant of OH groups changed up to 50%) by nuclear magnetic resonance (NMR) analysis. Remarkably, the glucopyranose rings underwent partial dehydration during the thermal exposure resulting in enol formation. This study confirms the chain mobility that could lead to the conformational and dimensional changes of the CNFs during thermal exposure. The broad range of conformations was defined by the dihedral angles that varied from ±27° to ±139° after thermal exposure. Investigation into the mechanism involving chemical transformation of the substrates during heating is important for the fabrication of the next generation of flexible electrical materials.
11.	Singh, Harishchandra, et al. (author) Unveiling nano-scaled chemical inhomogeneity impacts on corrosion of Ce-modified 2507 super-duplex stainless steels 2022 In: npj Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; 6:1 Journal article (peer-reviewed)abstract The widely used stainless steels and their deformed variants are anticorrosive in ambient conditions due to passivation layers composed of chromium oxides. Conventionally, corrosion and erosion of the steels are attributed to the breakdown of such layers but seldomly to the origin that depends on surface heterogeneity at the microscopic level. In this work, the nanometer-scaled chemical heterogeneity at the surface unveiled via spectro-microscopy and chemometric analysis unexpectedly dominates the breakdown and corrosion behavior of the cold-rolled Ce-modified 2507 super-duplex stainless steels (SDSS) over its hot-deformed counterpart. Though relatively uniformly covered by a native Cr2O3 layer revealed by X-ray photoemission electron microscopy, the cold-rolled SDSS behaved poorly in passivity because of locally distributed Fe3+ rich nano-islands over the Fe/Cr oxide layer. This atomic-level knowledge provides a deep understanding of corrosion of stainless steel and is expected to benefit corrosion controls of similar high-alloyed metals.
12.	Tobias, Mariano Marco, et al. (author) Plasma degradation of contaminated PPE : an energy-efficient method to treat contaminated plastic waste 2023 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 7:1 Journal article (peer-reviewed)abstract The use of PPE has drastically increased because of the SARS-CoV-2 (COVID-19) pandemic as disposable surgical face masks made from non-biodegradable polypropylene (PP) polymers have generated a significant amount of waste. In this work, a low-power plasma method has been used to degrade surgical masks. Several analytical techniques (gravimetric analysis, scanning electron microscopy (SEM), attenuated total reflection-infra-red spectroscopy (ATR-IR), x-ray photoelectron spectroscopy (XPS), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and wide-angle x-ray scattering (WAXS)) were used to evaluate the effects of plasma irradiation on mask samples. After 4 h of irradiation, an overall mass loss of 63 +/- 8%, through oxidation followed by fragmentation, was observed on the non-woven 3-ply surgical mask, which is 20 times faster than degrading a bulk PP sample. Individual components of the mask also showed different degradation rates. Air plasma clearly represents an energy-efficient tool for treating contaminated PPE in an environmentally friendly approach.
13.	Wei, Xin-Feng, et al. (author) Ageing properties and polymer/fuel interactions of polyamide 12 exposed to (bio)diesel at high temperature 2019 In: npj Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; :3 Journal article (peer-reviewed)abstract Biodiesel derived from oil crops and animal fats has been developed as a promising carbon-neutral alternative to petroleum fuels in the transport sector, but the compatibility between biodiesel/petroleum diesel and polymer components in the automotive fuel system has not been free from controversy. In this present study, the degradation of polyamide 12 (PA12), one of the most common polymers used in vehicle fuel systems, has been investigated after exposure to petroleum diesel, biodiesel and a mixture of these (20 vol.% of biodiesel/80 vol.% petroleum diesel). Fuel sorption kinetics, glass transition temperature data and mechanical properties all showed that the fuels plasticized the PA12. In addition, monomers and oligomers were extracted from PA12 by the fuels. The long-term exposure led to oxidation and an annealing-induced increase in crystallinity of the polymer. The plasticization, oxidation and annealing effects were combined with the tensile mechanical properties to assess the overall degree of ageing and degradation of the PA12 material. The fuel-polymer interactions and ageing mechanisms, demonstrated here at high temperature for PA12, are 'generic' in the sense that they are also expected to occur, to various degrees, with many other polymers and they indicate that care should be taken when choosing polymers in applications where they will be exposed to fuels at high temperature.
14.	Wei, Xin-Feng, et al. (author) Performance of glass fiber reinforced polyamide composites exposed to bioethanol fuel at high temperature 2022 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 6:1 Journal article (peer-reviewed)abstract The increasing use of bioethanol fuel, as a promising carbon-neutral alternative to petroleum-based gasoline, has raised concerns on compatibility issues between bioethanol and the polymer components used in the automotive fuel system. Here, the performance of two commercial glass-fiber reinforced polyamide composites (polyamide 12 (PA12) and an aromatic highly-biobased polyamide (polyphthalamide, PPA)) exposed to a mixture of ethanol and gasoline (E25 fuel), was investigated at high temperature (120 degrees C). The polyamide matrices showed a fast and remarkably high fuel uptake. The sorbed fuel had a strong plasticizing effect on both materials, as revealed by the large decrease in the glass transition temperature and a 60% decrease in stiffness and strength. The PPA, however, sustained degradation better than the PA12, which experienced swelling-induced surface cracking and oxidation-induced embrittlement. The results suggest that care should be taken when using polyamide composites in ethanol-based fuel applications at this high temperature level.
15.	Wei, Xin-Feng, et al. (author) Plasticiser loss from plastic or rubber products through diffusion and evaporation 2019 In: npj Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; 3:1 Journal article (peer-reviewed)abstract Polymers experience degradation during storage and service. One of the main degradation mechanisms of plasticised-polymer products is the loss of plasticiser, which leads to poorer mechanical properties and eventual contamination of the surrounding environment. This paper addresses the kinetics and predictions of plasticiser migration from polymers to a surrounding gas phase, an important issue for plastic and rubber products exposed to high service temperature conditions and during accelerated ageing and testing. The features and factors influencing the two migration-rate-limiting modes (plasticiser evaporation and diffusion), as well as migration issues related to bio-based plasticisers and plasticiser-biopolymer systems, are discussed.
16.	Yue, Xiaoqi, et al. (author) Effect of hydrogen on the passivation for ultra-thin 316 L SS foil 2023 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 7:1 Journal article (peer-reviewed)abstract The reformation and characterisation of the passive film formed on ultra-thin 316 L after hydrogen charging is investigated by combining EBSD, TMDS, XRD, Synchrotron-based XPS, and electrochemical experiments. The results show that ultra-thin foil reforms a passive film after 12 h of hydrogen release in NaCl solution. The reformed passive film is half the thickness of the as-received passive film and is dominated by Cr oxides/hydroxides. The lattice extension caused by residual hydrogen accelerates Cr migration to form Cr2O3; while the diffusible hydrogen occupies the cation vacancies and results in high defect density for the reformed passive film within 12 h.
17.	Zeller-Plumhoff, Berit, et al. (author) Oxygen-sensitive nanoparticles reveal the spatiotemporal dynamics of oxygen reduction during magnesium implant biodegradation 2022 In: npj Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; 6:1 Journal article (peer-reviewed)abstract Magnesium (Mg) alloys are becoming increasingly important in the biomedical field as temporary bone implants. However, the biodegradation process of Mg alloys is highly complex and recent findings suggest that oxygen (O2) consumption is non-negligible. In this study, we give experimental proof of O2 consumption during Mg degradation under physiological conditions. Specifically, we study pure Mg, Mg–6 wt%Ag and Mg–5 wt%Gd in Hanks’ balanced salt solution and Dulbecco’s modified Eagle’s medium. We show that O2 consumption and hydrogen evolution are inversely correlated and that O2 concentrations remain below 7.5% in certain cases, which could have significant implications for bone healing.
18.	Örnek, Cem, et al. (author) Passive film characterisation of duplex stainless steel using scanning Kelvin probe force microscopy in combination with electrochemical measurements 2019 In: npJ Materials Degradation. - : Springer Science and Business Media LLC. - 2397-2106. ; 3:1, s. 1-8 Journal article (peer-reviewed)abstract The characterisation of passive oxide films on heterogeneous microstructures is needed to assess local degradation (corrosion, cracking) in aggressive environments. The Volta potential is a surface-sensitive parameter which can be used to assess the surface nobility and hence passive films. In this work, it is shown that the Volta potential, measured on super duplex stainless steel by scanning Kelvin probe force microscopy, correlates with the electrochemical properties of the passive film, measured by electrochemical impedance spectroscopy and potentiodynamic polarisation. Natural oxidation by ageing in ambient air as well as artificial oxidation by immersion in concentrated nitric acid improved the nobility, both reflected by increased Volta potentials and electrochemical parameters. Passivation was associated with vanishing of the inherent Volta potential difference between the ferrite and austenite, thereby reducing the galvanic coupling and hence improving the corrosion resistance of the material. Hydrogen-passive film interactions, triggered by cathodic polarisation, however, largely increased the Volta potential difference between the phases, resulting in loss of electrochemical nobility, with the ferrite being more affected than the austenite. A correlative approach of using the Volta potential in conjunction with electrochemical data has been introduced to characterise the nobility of passive films in global and local scale.
19.	Örnek, Cem, et al. (author) Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires 2018 In: NPJ MATERIALS DEGRADATION. - : Springer Nature. - 2397-2106. ; 2:1 Journal article (peer-reviewed)abstract Corrosion rates of strained grade UNS S32202 (2202) and UNS S32205 (2205) duplex stainless steel wires have been measured, in situ, using time-lapse X-ray computed tomography. Exposures to chloride-containing (MgCl2) atmospheric environments at 50 degrees C (12-15 M Cl(-)and pH similar to 5) with different mechanical elastic and elastic/plastic loads were carried out over a period of 21 months. The corrosion rates for grade 2202 increased over time, showing selective dissolution with shallow corrosion sites, coalescing along the surface of the wire. Corrosion rates of grade 2205 decreased over time, showing both selective and pitting corrosion with more localised attack, growing preferentially in depth. The nucleation of stress corrosion cracking was observed in both wires. Stainless steel: Comprehending corrosion The corrosion of two grades of stainless steel has been studied, in situ, under atmospheric exposure conditions. Grade '2205' duplex stainless steel (DSS) has been suggested as a possible container material for the storage of intermediate-level radioactive nuclear waste in the UK because of its high resistance to corrosion and stress corrosion cracking (SCC). Now a team led by D. Engelberg from The University of Manchester, United Kingdom, have used time-lapse X-ray computed tomography to determine the corrosion rates of strained grade '2202' and '2205' DSS wires-over the course of 21 months-that had been exposed to a chloride-containing thin-film electrolyte. They saw that although the corrosion rate of grade 2202 DSS wires increased with time, the corrosion rate for grade 2205 decreased, confirming its superior corrosion resistance. They also observed the nucleation of SCC cracks in both grades of wire and demonstrated that duplex stainless steels can suffer from low-temperature SCC.
20.	Delrez, Laetitia, et al. (author) Transit detection of the long-period volatile-rich super-Earth nu(2) Lupi d with CHEOPS 2021 In: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; :5, s. 775-787 Journal article (peer-reviewed)abstract Exoplanets transiting bright nearby stars are key objects for advancing our knowledge of planetary formation and evolution. The wealth of photons from the host star gives detailed access to the atmospheric, interior and orbital properties of the planetary companions. nu(2) Lupi (HD 136352) is a naked-eye (V = 5.78) Sun-like star that was discovered to host three low-mass planets with orbital periods of 11.6, 27.6 and 107.6 d via radial-velocity monitoring(1). The two inner planets (b and c) were recently found to transit(2), prompting a photometric follow-up by the brand new Characterising Exoplanets Satellite (CHEOPS). Here, we report that the outer planet d is also transiting, and measure its radius and mass to be 2.56 +/- 0.09 R-circle plus and 8.82 +/- 0.94 M-circle plus, respectively. With its bright Sun-like star, long period and mild irradiation (similar to 5.7 times the irradiation of Earth), nu(2) Lupi d unlocks a completely new region in the parameter space of exoplanets amenable to detailed characterization. We refine the properties of all three planets: planet b probably has a rocky mostly dry composition, while planets c and d seem to have retained small hydrogen-helium envelopes and a possibly large water fraction. This diversity of planetary compositions makes the nu(2) Lupi system an excellent laboratory for testing formation and evolution models of low-mass planets.
21.	Roth, Lorenz, et al. (author) A sublimated water atmosphere on Ganymede detected from Hubble Space Telescope observations 2021 In: Nature Astronomy. - : Springer Nature. - 2397-3366. ; 5:10, s. 1043-1051 Journal article (peer-reviewed)abstract Ganymede’s atmosphere is produced by charged particle sputtering and sublimation of its icy surface. Previous far-ultraviolet observations of the O i 1,356 Å and O i 1,304 Å oxygen emissions were used to infer sputtered molecular oxygen (O2) as an atmospheric constituent, but an expected sublimated water (H2O) component remained undetected. Here we present an analysis of high-sensitivity spectra and spectral images acquired by the Hubble Space Telescope revealing H2O in Ganymede’s atmosphere. The relative intensity of the oxygen emissions requires contributions from the dissociative excitation of water vapour, indicating that H2O is more abundant than O2 around the subsolar point. Away from the subsolar region, the emissions are consistent with a pure O2 atmosphere. Eclipse observations constrain atomic oxygen to be at least two orders of magnitude less abundant than these other species. The higher H2O/O2 ratio above the warmer trailing hemisphere compared with the colder leading hemisphere, the spatial concentration in the subsolar region and the estimated abundance of ~1015 molecules of H2O per cm2 are consistent with sublimation of the icy surface as source.
22.	Diarberkali, Elias, et al. (author) Adolescents with and without idiopathic scoliosis have similar self-reported level of physical activity : a cross-sectional study 2016 In: Scoliosis and Spinal Disorders. - : BioMed Central. - 2397-1789. ; 11:17, s. 1-7 Journal article (peer-reviewed)abstract BACKGROUND:Little is known about physical activity levels in individuals with idiopathic scoliosis. The aim of this study was to describe the level of physical activity in adolescents with and without idiopathic scoliosis.METHODS:Two hundred thirty-nine adolescents, median (25th, 75th percentile) age 16.0 (14.4, 17.6) with idiopathic scoliosis and 58 randomly recruited population-based individuals without scoliosis aged 14.6 (12.8, 16.3) participated. The 239 idiopathic scoliosis patients consisted of 88 untreated, 43 previously braced, 36 with ongoing brace-treatment and 72 surgically treated individuals. Main outcome measure was the proportion achieving at least moderate activity level, as estimated by the International Physical Activity Questionnaire short form (IPAQ-SF). Other outcome measures were Metabolic Equivalent Task (MET) minutes/week, time spent sitting, spare time activity level and sporting activities. Statistical analyses were adjusted for age and sex.RESULTS:The proportion of individuals with scoliosis with moderate activity level was 180 out of 239 (75 %) and for individuals without scoliosis 49 out of 58 (85 %) (p = 0.14). Median MET-minutes/week (25th,75th percentile) was for individuals with scoliosis scoliosis 1977 (840,3777) and for individuals without scoliosis 2120 (887,4598) (p = 0.11). Sporting activities did not differ (p = 0.28). The ongoing brace-treatment group had a significantly higher proportion of individuals categorizing themselves at high spare time activity level compared to the surgically treated and previously braced individuals (p = 0.046). No difference was seen between the treatment groups regarding the proportion achieving moderate activity (p = 0.11) and sporting activities (p = 0.20). Median MET minutes/week was 2160 (794,3797) for the untreated group, 989 (661,2706) for the previously braced group, 2055 (1010, 4026) for the surgery group and 2106 (990,4480) for the ongoing brace-treatment group (p = 0.031).CONCLUSION:Adolescents with idiopathic scoliosis show similar levels of self-reported physical activity as individuals without idiopathic scoliosis. Bracing and surgery do not appear to inhibit physical activity.

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