4,268 research outputs found

    An electro-hydrodynamics modeling of droplet actuation on solid surface by surfactant-mediated electro-dewetting

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    We propose an electro-hydrodynamics model to describe the dynamic evolution of a slender drop containing a dilute ionic surfactant on a naturally wettable surface, with a varying external electric field. This unified model reproduces fundamental microfluidic operations controlled by electrical signals, including dewetting, rewetting, and droplet shifting. In this paper, lubrication theory analysis and numerical simulations illustrate how to electrically control the wettability of surface via the charged surfactant. Our numerical results show that electric field promotes dewetting by attracting ionic surfactants onto the transition thin-film region and promotes rewetting by attracting them away from the region.Comment: 16 pages, 13 figure

    Reply to: Atom gravimeters and the gravitational redshift

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    We stand by our result [H. Mueller et al., Nature 463, 926-929 (2010)]. The comment [P. Wolf et al., Nature 467, E1 (2010)] revisits an interesting issue that has been known for decades, the relationship between test of the universality of free fall and redshift experiments. However, it arrives at its conclusions by applying the laws of physics that are questioned by redshift experiments; this precludes the existence of measurable signals. Since this issue applies to all classical redshift tests as well as atom interferometry redshift tests, these experiments are equivalent in all aspects in question.Comment: Reply to P. Wolf et al., arXiv:1009.060

    Assessment and in vivo scoring of murine experimental autoimmune uveoretinitis using optical coherence tomography

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    Despite advances in clinical imaging and grading our understanding of retinal immune responses and their morphological correlates in experimental autoimmune uveoretinitis (EAU), has been hindered by the requirement for post-mortem histology. To date, monitoring changes occurring during EAU disease progression and evaluating the effect of therapeutic intervention in real time has not been possible. We wanted to establish whether optical coherence tomography (OCT) could detect intraretinal changes during inflammation and to determine its utility as a tool for accurate scoring of EAU. EAU was induced in C57BL/6J mice and animals evaluated after 15, 26, 36 and 60 days. At each time-point, contemporaneous Spectralis-OCT scanning, topical endoscopic fundal imaging (TEFI), fundus fluorescein angiography (FFA) and CD45-immunolabelled histology were performed. OCT features were further characterised on retinal flat-mounts using immunohistochemistry and 3D reconstruction. Optic disc swelling and vitreous opacities detected by OCT corresponded to CD45+ cell infiltration on histology. Vasculitis identified by FFA and OCT matched perivascular myeloid and T-cell infiltrates and could be differentiated from unaffected vessels. Evolution of these changes could be followed over time in the same eye. Retinal folds were visible and found to encapsulate mixed populations of activated myeloid cells, T-cells and microglia. Using these features, an OCT-based EAU scoring system was developed, with significant correlation to validated histological (Pearson r(2) = 0.6392, P<0.0001, n = 31 eyes) and TEFI based scoring systems (r(2) = 0.6784, P<0.0001). OCT distinguishes the fundamental features of murine EAU in vivo, permits dynamic assessment of intraretinal changes and can be used to score disease severity. As a result, it allows tissue synchronisation with subsequent cellular and functional assessment and greater efficiency of animal usage. By relating OCT signals with immunohistochemistry in EAU, our findings offer the opportunity to inform the interpretation of OCT changes in human uveitis

    Cataract surgery in uveitis: a multicentre database study

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    BACKGROUND/AIMS: Cataract is an important source of visual loss in patients with uveitis. Whether or not outcomes of cataract surgery in eyes with uveitis are worse compared with non-uveitic eyes have to date been compromised by lack of reliable estimates of benefit and harm, which require data from large cohorts. METHODS: Electronic medical record data were extracted from eight independent UK clinical sites for eyes undergoing cataract extraction between January 2010 and December 2014. 1173 eyes with a recorded diagnosis of uveitis were compared with a reference group of 95 573 eyes from the same dataset. RESULTS: Uveitic eyes represented 1.2% of all eyes undergoing cataract surgery. Eyes in the uveitic group had worse preoperative visual acuity (0.87 vs 0.65 logarithm of the minimum angle of resolution (logMAR) units), were from younger patients and had shorter axial lengths and a higher incidence of ocular copathology including glaucoma. A greater number had documented small pupils, required additional surgical procedures, developed more intraoperative complications and had poorer postoperative visual acuity at all time points measured up to 6 months (0.41 vs 0.27 logMAR units at 12-24 weeks). CONCLUSIONS: This large study cohort of eyes with a diagnosis of uveitis undergoing cataract surgery highlights more precisely the complex surgical demands, copathology and worse visual outcomes in this group. These data will allow more accurate preoperative counselling and planning. Although improvement in visual acuity is achieved in most cases, prognosis should be guarded, so that patient expectations are met. Compared with the non-uveitic population, the mean postoperative visual acuity is between one and two lines worse at all time points

    New gold nanostructures for sensor applications: a review

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    Gold based structures such as nanoparticles (NPs) and nanowires (NWs) have widely been used as building blocks for sensing devices in chemistry and biochemistry fields because of their unusual optical, electrical and mechanical properties. This article gives a detailed review of the new properties and fabrication methods for gold nanostructures, especially gold nanowires (GNWs), and recent developments for their use in optical and electrochemical sensing tools, such as surface enhanced Raman spectroscopy (SERS). &copy; 2014 by the authors; licensee MDPI, Basel, Switzerland

    A Self-Reference False Memory Effect in the DRM Paradigm: Evidence from Eastern and Western Samples

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    It is well established that processing information in relation to oneself (i.e., selfreferencing) leads to better memory for that information than processing that same information in relation to others (i.e., other-referencing). However, it is unknown whether self-referencing also leads to more false memories than other-referencing. In the current two experiments with European and East Asian samples, we presented participants the Deese-Roediger/McDermott (DRM) lists together with their own name or other people’s name (i.e., “Trump” in Experiment 1 and “Li Ming” in Experiment 2). We found consistent results across the two experiments; that is, in the self-reference condition, participants had higher true and false memory rates compared to those in the other-reference condition. Moreover, we found that selfreferencing did not exhibit superior mnemonic advantage in terms of net accuracy compared to other-referencing and neutral conditions. These findings are discussed in terms of theoretical frameworks such as spreading activation theories and the fuzzytrace theory. We propose that our results reflect the adaptive nature of memory in the sense that cognitive processes that increase mnemonic efficiency may also increase susceptibility to associative false memories

    Uptake and transport of novel amphiphilic polyelectrolyte-insulin nanocomplexes by caco-2 cells - towards oral insulin

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    “The original publication is available at www.springerlink.com”. Copyright SpringerPurpose: The influence of polymer architecture on cellular uptake and transport across Caco-2 cells of novel amphiphilic polyelectrolyte-insulin nanocomplexes was investigated. Method: Polyallylamine (PAA) (15 kDa) was grafted with palmitoyl chains (Pa) and subsequently modified with quaternary ammonium moieties (QPa). These two amphiphilic polyelectrolytes (APs) were tagged with rhodamine and their uptake by Caco-2 cells or their polyelectrolyte complexes (PECs) with fluorescein isothiocyanate-insulin (FITC-insulin) uptake were investigated using fluorescence microscopy. The integrity of the monolayer was determined by measurement of transepithelial electrical resistance (TEER). Insulin transport through Caco-2 monolayers was determined during TEER experiments. Result: Pa and insulin were co-localised in the cell membranes while QPa complexes were found within the cytoplasm. QPa complex uptake was not affected by calcium, cytochalasin D or nocodazole. Uptake was reduced by co-incubation with sodium azide, an active transport inhibitor. Both polymers opened tight junctions reversibly where the TEER values fell by up to 35 % within 30 minutes incubation with Caco-2 cells. Insulin transport through monolayers increased when QPa was used (0.27 ngmL-1 of insulin in basal compartment) compared to Pa (0.14 ngmL-1 of insulin in basal compartment) after 2 hours. Conclusion: These APs have been shown to be taken up by Caco-2 cells and reversibly open tight cell junctions. Further work is required to optimise these formulations with a view to maximising their potential to facilitate oral delivery of insulin.Peer reviewe

    Multimodal analysis of ocular inflammation using the endotoxin-induced uveitis mouse model

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    Endotoxin-induced uveitis (EIU) in rodents is a model of acute Toll-like receptor 4 (TLR4)-mediated organ inflammation, and has been used to model human anterior uveitis, examine leukocyte trafficking and test novel anti-inflammatory therapeutics. Wider adoption has been limited by the requirement for manual, non-specific, cell-count scoring of histological sections from each eye as a measure of disease severity. Here, we describe a comprehensive and efficient technique that uses ocular dissection and multimodal tissue analysis. This allows matched disease scoring by multicolour flow cytometric analysis of the inflammatory infiltrate, protein analysis on ocular supernatants and qPCR on remnant tissues of the same eye. Dynamic changes in cell populations could be identified and mapped to chemokine and cytokine changes over the course of the model. To validate the technique, dose-responsive suppression of leukocyte infiltration by recombinant interleukin-10 was demonstrated, as well as selective suppression of the monocyte (CD11b+Ly6C+) infiltrate, in mice deficient for eitherCcl2orCcr2 Optical coherence tomography (OCT) was used for the first time in this model to allowin vivoimaging of infiltrating vitreous cells, and correlated with CD11b+Ly6G+ counts to provide another unique measure of cell populations in the ocular tissue. Multimodal tissue analysis of EIU is proposed as a new standard to improve and broaden the application of this model

    'Asexual isn't who I am': the politics of asexuality

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    Some literature on asexuality has claimed that it is inherently radical and contains the potential for resistance. Unfortunately, this literature has tended to be unempirical, has imagined asexuality as a disembodied entity, and has marginalised the multiple identities held by asexual people. This article, inspired by Plummer’s critical humanist approach, seeks to explore how individuals understand their asexuality to encourage forms of political action in the areas of identity, activism, online spaces, and LGBT politics. What we found was a plurality of experiences and attitudes with most adopting a pragmatic position in response to their social situation which saw large-scale political action as irrelevant. We conclude by reflecting on what these results mean for those who see asexuality as potentially radical
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