surface-diffusion
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We report a powerful method for capturing the time-resolved concentration profiles, liquid swelling and surface phenomena during the absorption of methane (CH4) in still liquid ethanol (C2D6O) and n-decane (n-C10D22) and at high spatial resolution (pixel size 21.07 μm) using neutron imaging. Absorption of supercritical methane was followed at two temperatures and two pressures of methane, namely 7.0, 37.8 °C and 80, 120 bar. Fick's second law, which was used in the liquid-fixed coordinates, enabled for an adequate parameterization of the observed concentration profiles and liquid levels using simple analytical expressions. For both studied liquids, anomalously slow diffusion was observed in the initial stage of the absorption experiment. This was ascribed to the slow formation of the surface excess on the interface, time constant ranged 130-275 s. The axial symmetry of the cell allowed for the tomographic reconstructions of the profiles of the menisci. Based on these profiles, contact angle and surface tension were evaluated using the Young-Laplace equation. Overall, neutron imaging made it possible to capture time- and space-resolved information from which the methane concentration, liquid level and meniscus shape under high-pressure conditions inside a cylindrical titanium vessel were quantitatively derived. Multiple characteristics of ethanol, a methane hydrate inhibitor, and n-decane, a model constituent of crude oil, were thus measured for the first time under industrially relevant conditions in a one-pot experiment.
- MeSH
- anestetika lokální chemie MeSH
- glycerol chemie MeSH
- karbamáty chemie MeSH
- povrchové napětí MeSH
- propylenglykoly chemie MeSH
- sorbitol chemie MeSH
- Publikační typ
- srovnávací studie MeSH
The corpus callosum is the brain's largest commissural fiber tract and is crucial for interhemispheric integration of neural information. Despite the high relevance of the corpus callosum for several cognitive systems, the molecular determinants of callosal microstructure are largely unknown. Recently, it was shown that genetic variations in the myelin-related proteolipid 1 gene PLP1 and the axon guidance related contactin 1 gene CNTN1 were associated with differences in interhemispheric integration at the behavioral level. Here, we used an innovative new diffusion neuroimaging technique called neurite orientation dispersion and density imaging (NODDI) to quantify axonal morphology in subsections of the corpus callosum and link them to genetic variation in PLP1 and CNTN1. In a cohort of 263 healthy human adults, we found that polymorphisms in both PLP1 and CNTN1 were significantly associated with callosal microstructure. Importantly, we found a double dissociation between gene function and neuroimaging variables. Our results suggest that genetic variation in the myelin-related gene PLP1 impacts white matter microstructure in the corpus callosum, possibly by affecting myelin structure. In contrast, genetic variation in the axon guidance related gene CNTN1 impacts axon density in the corpus callosum. These findings suggest that PLP1 and CNTN1 gene variations modulate specific aspects of callosal microstructure that are in line with their gene function.
- MeSH
- bílá hmota anatomie a histologie MeSH
- corpus callosum anatomie a histologie MeSH
- difuzní magnetická rezonance metody MeSH
- dospělí MeSH
- genotyp MeSH
- jednonukleotidový polymorfismus MeSH
- kontaktin 1 genetika fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- myelinová pochva genetika MeSH
- myelinový proteolipidový protein genetika fyziologie MeSH
- neurity * MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium.
- MeSH
- biokompatibilní materiály chemie MeSH
- difuze MeSH
- hořčík chemie MeSH
- hutnictví metody MeSH
- kovové nanočástice chemie ultrastruktura MeSH
- pevnost v tlaku MeSH
- plazmové plyny chemie MeSH
- poréznost MeSH
- povrchové vlastnosti MeSH
- prášky, zásypy, pudry MeSH
- testování materiálů MeSH
- tvrdost MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- autoimunitní nemoci diagnóza etiologie komplikace MeSH
- bolest etiologie MeSH
- dermatomyozitida diagnóza etiologie MeSH
- diferenciální diagnóza MeSH
- difuzní magnetická rezonance metody využití MeSH
- dítě MeSH
- edém diagnóza etiologie komplikace MeSH
- elektromyografie využití MeSH
- klinické laboratorní techniky využití MeSH
- ultrasonografie využití MeSH
- Check Tag
- dítě MeSH
- Publikační typ
- kazuistiky MeSH
