419 research outputs found
A surfactantless emulsion as a model for the liquid-liquid interface.
An electrochemically polarised liquid-liquid interface in the form of a surfactantless oil-in-water emulsion has been developed, and its creation, stabilisation and use as a model liquid-liquid system for structural characterisation using Small Angle Neutron Scattering (SANS) are described. The emulsion, composed of 1,2-dichloroethane (DCE)-in-D20, was created using a condensation method and the two main processes of destabilisation, sedimentation and coalescence, were minimised using density-matching and electrochemistry. The stabilised emulsion interface was then studied with SANS, using the Dll and D22 diffractometers at the ILL and LOQ at ISIS. This was to determine structural information regarding a layer of adsorbed Bovine Serum Albumin (BSA) protein at the interface with and without stabilising salts and the only analysable results were obtained using Dll, due to the lower Q-range accessible. The BSA layer thickness was determined to be 40 and 48 A for emulsions with and without salts respectively, and this was comparable with the literature thickness of 40 A. Another use for the surfactantless emulsion would be for electrodeless electrodeposition of metals at the interface, utilising the interfacial potential, and preliminary experiments were carried out using both oil-in-water and water-in-oil emulsions
Alpha-1 antitrypsin mitigates the inhibition of airway epithelial cell repair by neutrophil elastase
Copyright © 2016 by the American Thoracic Society. Neutrophil elastase (NE) activity is associated with many destructive lung diseases and is a predictor for structural lung damage in early cystic fibrosis (CF), which suggests normal maintenance of airway epitheliumis prevented byuninhibitedNE.However, limited data exist on how the NE activity in airways of very young children with CF affects function of the epithelia. The aimof this studywas to determine if NE activity could inhibit epithelial homeostasis and repair and whether any functional effect was reversible by antiprotease alpha-1 antitrypsin (a1AT) treatment. Viability, inflammation, apoptosis, and proliferation were assessed in healthy non-CF and CF pediatric primary airway epithelial cells (pAEC non-CF and pAEC CF , respectively) during exposure to physiologically relevant NE. The effect of NE activity on pAEC CF wound repair was also assessed.We report that viability after 48 hours was significantly decreased by 100 nM NE in pAEC non-CF and pAEC CF owing to rapid cellular detachment that was accompanied by inflammatory cytokine release. Furthermore, both phenotypes initiated an apoptotic response to 100 nM NE, whereas ≥50 nM NE activity significantly inhibited the proliferative capacity of cultures. Similar concentrations of NE also significantly inhibited wound repair of pAEC CF , but this effect was reversed by the addition of a1AT. Collectively, our results demonstrate free NE activity is deleterious for epithelial homeostasis and support the hypothesis that proteases inthe airway contribute directly toCF structural lung disease. Our results also highlight the need to investigate antiprotease therapies in early CF disease in more detail
Convective Motion in a Vibrated Granular Layer
Experimental results are presented for a vertically shaken granular layer. In
the range of accelerations explored, the layer develops a convective motion in
the form of one or more rolls. The velocity of the grains near the wall has
been measured. It grows linearly with the acceleration, then the growing rate
slows down. A rescaling with the amplitude of the wall velocity and the height
of the granular layer makes all data collapse in a single curve. This can
provide insights on the mechanism driving the motion.Comment: 10 pages, 5 figures submitted to Phys. Rev. Let
Full quantum solutions to the resonant four-wave mixing of two single-photon wave packets
We analyze both analytically and numerically the resonant four-wave mixing of
two co-propagating single-photon wave packets. We present analytic expressions
for the two-photon wave function and show that soliton-type quantum solutions
exist which display a shape-preserving oscillatory exchange of excitations
between the modes. Potential applications including quantum information
processing are discussed.Comment: 7 pages, 3 figure
A global review of approaches to animal health priority setting and resource allocation, 2000 -2021: A structured, systematic scoping review
Objective
The objective of this scoping review was to identify and describe methods that have been used to
prioritise animal diseases to allocate resources for interventions associated with disease control,
surveillance or research.
Materials and methods
Three electronic databases (Medline/PubMed, Embase and CAB Abstracts) were searched using
syntax with inclusion and exclusion criteria. The search identified 6395 articles after de-duplication.
Upon manual searching, an additional 64 articles were added. A total of 6460 articles were finally
imported to an online systematic review management software (sysrev.com) for screening. Based
on inclusion and exclusion criteria, 532 articles passed the first screening and after the second
round of screening, 336 were recommended for a full review.
Results
The main methods of disease prioritisation identified were based on economic analysis, multi-criteria
evaluation, risk assessment (qualitative, quantitative or semi-quantitative), simple ranking, spatial
risk mapping and simulation modelling. Disease prioritisation was performed for the following
reasons: 1) disease control, prevention or eradication strategies, 2) identification priority of diseases
to inform general organisational strategy, 3) identification of high-risk areas or populations, 4)
assessment of the risk of disease introduction or occurrence, 5) disease surveillance and 6)
research priority setting. With regard to the geographical focus of the 336 articles prioritisation
studies and assessments screened 49% had a national focus, 13% were local, 12% were regional,
7% were sub-national and 4% were global; 16% had no particular geographic focus.
Conclusion
This review describes the different approaches available for prioritising animal health investments
and reflects on the pros and cons of different approaches. It also considers approaches used in
other fields such as environment and human health and reflects on their suitability for animal health
decision making
Evaluating situational judgment test use and diversity in admissions at a southern US medical school
Introduction Situational judgment tests have been adopted by medical schools to assess decision-making and ethical characteristics of applicants. These tests are hypothesized to positively affect diversity in admissions by serving as a noncognitive metric of evaluation. The purpose of this study was to evaluate the performance of the Computer-based Assessment for Sampling Personal Characteristics (CASPer) scores in relation to admissions interview evaluations. Methods This was a cohort study of applicants interviewing at a public school of medicine in the southeastern United States in 2018 and 2019. Applicants took the CASPer test prior to their interview day. In-person interviews consisted of a traditional interview and multiple-mini-interview (MMI) stations. Between subjects, analyses were used to compare scores from traditional interviews, MMIs, and CASPer across race, ethnicity, and gender. Results 1,237 applicants were interviewed (2018: n = 608; 2019: n = 629). Fifty-seven percent identified as female. Self-identified race/ethnicity included 758 White, 118 Black or African-American, 296 Asian, 20 Native American or Alaskan Native, 1 Native Hawaiian or Other Pacific Islander, and 44 No response; 87 applicants identified as Hispanic. Black or African-American, Native American or Alaskan Native, and Hispanic applicants had significantly lower CASPer scores than other applicants. Statistically significant differences in CASPer percentiles were identified for gender and race; however, between subjects, comparisons were not significant. Conclusions The CASPer test showed disparate scores across racial and ethnic groups in this cohort study and may not contribute to minimizing bias in medical school admissions
Onset of fluidization in vertically shaken granular material
When granular material is shaken vertically one observes convection, surface
fluidization, spontaneous heap formation and other effects. There is a
controversial discussion in literature whether there exists a threshold for the
Froude number below which these effects cannot be
observed anymore. By means of theoretical analysis and computer simulation we
find that there is no such single threshold. Instead we propose a modified
criterion which coincides with critical Froude number for small
driving frequency .Comment: 7 pages, 5 figure
Bifurcations of a driven granular system under gravity
Molecular dynamics study on the granular bifurcation in a simple model is
presented. The model consists of hard disks, which undergo inelastic
collisions; the system is under the uniform external gravity and is driven by
the heat bath. The competition between the two effects, namely, the
gravitational force and the heat bath, is carefully studied. We found that the
system shows three phases, namely, the condensed phase, locally fluidized
phase, and granular turbulent phase, upon increasing the external control
parameter. We conclude that the transition from the condensed phase to the
locally fluidized phase is distinguished by the existence of fluidized holes,
and the transition from the locally fluidized phase to the granular turbulent
phase is understood by the destabilization transition of the fluidized holes
due to mutual interference.Comment: 35 pages, 17 figures, to be published in PR
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