38 research outputs found
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Liquids on Topologically Nanopatterned Surfaces
We report here surface x-ray scattering studies of the adsorption of simple hydrocarbon liquid films on nanostructured surfacesâsilicon patterned by an array of nanocavities. Two different regimes, filling and growing, are observed for the wetting film evolution as a function of the chemical potential offset from the bulk liquid-vapor coexistence. The strong influence of geometrical effects is manifested by a dependence of liquid adsorption in the nanocavities that is stronger than the van der Waals behavior for flat surfaces. The observed dependence is, however, much weaker than predicted for the infinitely deep parabolic cavities, suggesting that the finite-size effects contribute significantly to the observed adsorption behavior.Engineering and Applied Science
Capillary filling with wall corrugations] Capillary filling in microchannels with wall corrugations: A comparative study of the Concus-Finn criterion by continuum, kinetic and atomistic approaches
We study the impact of wall corrugations in microchannels on the process of
capillary filling by means of three broadly used methods - Computational Fluid
Dynamics (CFD), Lattice-Boltzmann Equations (LBE) and Molecular Dynamics (MD).
The numerical results of these approaches are compared and tested against the
Concus-Finn (CF) criterion, which predicts pinning of the contact line at
rectangular ridges perpendicular to flow for contact angles theta > 45. While
for theta = 30, theta = 40 (no flow) and theta = 60 (flow) all methods are
found to produce data consistent with the CF criterion, at theta = 50 the
numerical experiments provide different results. Whilst pinning of the liquid
front is observed both in the LB and CFD simulations, MD simulations show that
molecular fluctuations allow front propagation even above the critical value
predicted by the deterministic CF criterion, thereby introducing a sensitivity
to the obstacle heigth.Comment: 25 pages, 8 figures, Langmuir in pres
A positioning pillow to improve lumbar puncture success rate in paediatric haematology-oncology patients: a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Lumbar punctures (LPs) are common in children with cancer. Although pain management during the lumbar puncture has been well standardized, dealing with stress and anxiety is not well addressed yet. Our objective was to evaluate the potential improvement of the LP success rate using a positioning pillow, to ensure maximum lumbar flexion, and allow paravertebral muscles to relax, in children who are awake, with either conscious sedation or no sedation.</p> <p>Methods</p> <p>Children aged 2â18 years undergoing LP were randomly assigned to a positioning pillow or no intervention. The primary outcome was the rate of success, i.e. achieving the LP (sampling or injection) at the first attempt, without bleeding (RBC < 50/mm<sup>3</sup>). The secondary outcomes included: the child's pain, assessed by a self-administered visual analogical scales (VAS) for children over 6 years of age; the parents' and caregivers' perception of the child's pain; the satisfaction of the children, the parents, the caregivers and the physician. The child's cooperation and the occurrence of post-LP syndrome were also evaluated.</p> <p>Results</p> <p>124 children (62 in each group) were included. The LP pillow tended to increase the success rate of LPs (67% vs. 57%, p = 0.23), and decreased the post-LP syndromes (15% vs. 24%, p = 0.17) but the differences were not statistically significant. In children over 6-year of age (n = 72), the rate of success was significantly higher in the pillow group (58.5% vs. 41.5%, p = 0.031), with a tendency to feel less pain (median VAS 25 vs. 15 mm, p = 0.39) and being more satisfied (84.4% vs. 75.0%, p = 0.34).</p> <p>Conclusion</p> <p>Overall results do not demonstrate a benefit in using this pillow for lumbar punctures. This study results also suggest a benefit in the sub group of children over 6-year of age; this result needs confirmation.</p> <p>Trial Registration</p> <p>The trial was registered with Clinical Trials.gov (number NCT00775112).</p
Transcriptomic Effects-Based Monitoring for Endocrine Active Chemicals: Assessing Relative Contribution of Treated Wastewater to Downstream Pollution
The present study investigated whether
a combination of targeted
analytical chemistry information with unsupervised, data-rich biological
methodology (i.e., transcriptomics) could be utilized to evaluate
relative contributions of wastewater treatment plant (WWTP) effluents
to biological effects. The effects of WWTP effluents on fish exposed
to ambient, receiving waters were studied at three locations with
distinct WWTP and watershed characteristics. At each location, 4 d
exposures of male fathead minnows to the WWTP effluent and upstream
and downstream ambient waters were conducted. Transcriptomic analyses
were performed on livers using 15â000 feature microarrays,
followed by a canonical pathway and gene set enrichment analyses.
Enrichment of gene sets indicative of teleost brainâpituitaryâgonadalâhepatic
(BPGH) axis function indicated that WWTPs serve as an important source
of endocrine active chemicals (EACs) that affect the BPGH axis (e.g.,
cholesterol and steroid metabolism were altered). The results indicated
that transcriptomics may even pinpoint pertinent adverse outcomes
(i.e., liver vacuolization) and groups of chemicals that preselected
chemical analytes may miss. Transcriptomic Effects-Based monitoring
was capable of distinguishing sites, and it reflected chemical pollution
gradients, thus holding promise for assessment of relative contributions
of point sources to pollution and the efficacy of pollution remediation