1,047 research outputs found
Compound redistribution due to droplet evaporation on a thin polymeric film: theory
A thin polymeric film in contact with a fluid body may leach
low-molecular-weight compounds into the fluid. If this fluid is a small
droplet, the compound concentration within the liquid increases due to ongoing
leaching in combination with the evaporation of the droplet. This may
eventually lead to an inversion of the transport process and a redistribution
of the compounds within the thin film. In order to gain an understanding of the
compound redistribution, we apply a macroscopic model for the evaporation of a
droplet and combine that with a diffusion model for the compound transport. In
the model, material deposition and the resulting contact line pinning are
associated with the precipitation of a fraction of the dissolved material. We
find three power law regimes for the size of the deposit area as a function of
the initial droplet size, dictated by the competition between evaporation,
diffusion and the initial compound concentrations in the droplet and the thin
film. The strength of the contact line pinning determines the deposition
profile of the precipitate, characterised by a pronounced edge and a linearly
decaying profile towards the centre of the stain. Our predictions for the
concentration profile within the solid substrate resemble patterns found
experimentally.Comment: 12 pages, 10 figure
The effect of fatigue on plantar pressure distribution during running in view of running injuries
Uniformity of the lasing wavelength of heterogeneously integrated InP microdisk lasers on SOI
Integrated tunable quantum dot laser for optical coherence tomography in the 1.7μm wavelength region
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Stability investigation of polyPOSS-imide membranes for H2 purification and their application in the steel industry
In the present work, the high-temperature and long-term hydrothermal stability of novel polyPOSS-imide membranes for high-temperature hydrogen separation is investigated. The polyPOSS-imide membranes are found to exhibit an appropriate stability up to 300 C. Above this temperature the membrane selectivity rapidly decreases, which is seemingly related to changes in the molecular structure coupled to silanol condensation forming siloxane groups. Surprisingly, the exposure of the membrane to temperatures of up to 300 C even increases the H2 permeance together with the selective feature of the polyPOSS-imide layer. Subsequently, the long-term hydrothermal stability of the polyPOSS-imide membranes was investigated over a period of close to 1000 h at 250 C exposing the membrane to 10 mol% steam in the feed. An increase in H2/CH4 selectivity was observed upon water addition, and even though a minor drop was noticed over time during the hydrothermal operation, the selectivity exceeds the initial selectivity obtained in the dry feed atmosphere. After the removal of steam from the feed, the performance returns to its original state prior to the exposure to any steam showing appropriate steam stability of the polyPOSS-imide membranes. A conceptual process design and assessment was performed for application of these membranes involving a combination of carbon reuse and electrification of the steel making process with co-production of hydrogen. The results indicate a CO2 avoidance of 14%. The CO2 reduction achieved using renewable electricity in the proposed scheme is a factor 2.76 higher compared to a situation where the same renewable electricity would be fed in the electricity grid.publishedVersio
Bayesian Centroid Estimation for Motif Discovery
Biological sequences may contain patterns that are signal important
biomolecular functions; a classical example is regulation of gene expression by
transcription factors that bind to specific patterns in genomic promoter
regions. In motif discovery we are given a set of sequences that share a common
motif and aim to identify not only the motif composition, but also the binding
sites in each sequence of the set. We present a Bayesian model that is an
extended version of the model adopted by the Gibbs motif sampler, and propose a
new centroid estimator that arises from a refined and meaningful loss function
for binding site inference. We discuss the main advantages of centroid
estimation for motif discovery, including computational convenience, and how
its principled derivation offers further insights about the posterior
distribution of binding site configurations. We also illustrate, using
simulated and real datasets, that the centroid estimator can differ from the
maximum a posteriori estimator.Comment: 24 pages, 9 figure
Blood pressure and urinary sodium excretion in relation to the A-1984G adrenomedullin polymorphism in a Chinese population
Adrenomedullin (ADM) is a vasodilator and inhibits salt appetite. An A-to-G substitution at position -1984 in the promoter region of the ADM gene likely increases transcription. We therefore investigated this polymorphism in relation to blood pressure and urinary sodium in a Chinese population. We genotyped 427 Chinese enrolled in a family-based population study. We measured blood pressure by conventional sphygmomanometry and ambulatory monitoring. The frequencies of the ADM AA, AG, and GG genotypes were 50.6, 38.2, and 11.2%, respectively. In adjusted analyses, G allele carriers, compared to AA homozygotes, had significantly lower conventional (45.3 versus 48.5 mm Hg, P=0.004) and 24-h (42.6 versus 44.3 mm Hg, P=0.03) pulse pressures and urinary sodium excretion (143.8 versus 159.4 mmol/day, P=0.03). In parents, but not offspring, both systolic pressure and pulse pressure were significantly (P<0.01) lower in G allele carriers. The genotypic difference in sodium excretion was consistent across the age range. In 68 informative offspring, transmission of the G allele was associated with lower urinary sodium excretion (effect size, 40.1 mmol/day, P=0.01). In 81 healthy volunteers, the plasma ADM concentration was 15.2% higher in GG homozygotes than in sex- and age-matched AA subjects (11.4 versus 9.9 pmol/l, P=0.10). In conclusion, in Chinese, the ADM -1984G allele is associated with lower sodium excretion and in older subjects also with lower systolic pressure and narrower pulse pressure
Recurrent stroke risk and cerebral microbleed burden in ischemic stroke and TIA A meta-analysis
OBJECTIVE: To determine associations between cerebral microbleed (CMB) burden with recurrent
ischemic stroke (IS) and intracerebral hemorrhage (ICH) risk after IS or TIA.
METHODS: We identified prospective studies of patients with IS or TIA that investigated CMBs and
stroke (ICH and IS) risk during 5 CMBs)
and distribution. We calculated absolute event rates and pooled risk ratios (RR) using randomeffects
meta-analysis.
RESULTS: We included 5,068 patients from 15 studies. There were 115/1,284 (9.6%) recurrent IS
events in patients with CMBs vs 212/3,781 (5.6%) in patients without CMBs (pooled RR 1.8 for
CMBs vs no CMBs; 95% confidence interval [CI] 1.4–2.5). There were 49/1,142 (4.3%) ICH
events in those with CMBs vs 17/2,912 (0.58%) in those without CMBs (pooled RR 6.3 for CMBs
vs no CMBs; 95% CI 3.5–11.4). Increasing CMB burden increased the risk of IS (pooled RR [95%
CI] 1.8 [1.0–3.1], 2.4 [1.3–4.4], and 2.7 [1.5–4.9] for 1 CMB, 2–4 CMBs, and 5 CMBs, respectively).
CONCLUSIONS: CMBs are associated with increased stroke risk after IS or TIA. With increasing CMB
burden (compared to no CMBs), the risk of ICH increases more steeply than that of IS. However, IS
absolute event rates remain higher than ICH absolute event rates in all CMB burden categories
Diagnostic yield and accuracy in a tertiary referral syncope unit validating the ESC guideline on syncope:a prospective cohort study
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Responsive glyco-poly(2-oxazoline)s: synthesis, cloud point tuning, and lectin binding
A new sugar-substituted 2-oxazoline monomer was prepared using the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. Its copolymerization with 2-ethyl-2-oxazoline as well as 2-(dec-9-enyl)-2-oxazoline, yielding well-defined copolymers with the possibility to tune the properties by thiol-ene "click" reactions, is described. Extensive solubility studies on the corresponding glycocopolymers demonstrated that the lower critical solution temperature behavior and pH-responsiveness of these copolymers can be adjusted in water and phosphate-buffered saline (PBS) depending on the choice of the thiol. By conjugation of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose and subsequent deprotection of the sugar moieties, the hydrophilicity of the copolymer could be increased significantly, allowing a cloud-point tuning in the physiological range. Furthermore, the binding capability of the glycosylated copoly(2-oxazoline) to concanavalin A was investigated
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