4,390 research outputs found

    Achieving a Strongly Temperature-Dependent Casimir Effect

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    We propose a method of achieving large temperature sensitivity in the Casimir force that involves measuring the stable separation between dielectric objects immersed in fluid. We study the Casimir force between slabs and spheres using realistic material models, and find large > 2nm/K variations in their stable separations (hundreds of nanometers) near room temperature. In addition, we analyze the effects of Brownian motion on suspended objects, and show that the average separation is also sensitive to changes in temperature . Finally, this approach also leads to rich qualitative phenomena, such as irreversible transitions, from suspension to stiction, as the temperature is varied

    Improving Electronic Health Record Note Comprehension With NoteAid: Randomized Trial of Electronic Health Record Note Comprehension Interventions With Crowdsourced Workers

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    BACKGROUND: Patient portals are becoming more common, and with them, the ability of patients to access their personal electronic health records (EHRs). EHRs, in particular the free-text EHR notes, often contain medical jargon and terms that are difficult for laypersons to understand. There are many Web-based resources for learning more about particular diseases or conditions, including systems that directly link to lay definitions or educational materials for medical concepts. OBJECTIVE: Our goal is to determine whether use of one such tool, NoteAid, leads to higher EHR note comprehension ability. We use a new EHR note comprehension assessment tool instead of patient self-reported scores. METHODS: In this work, we compare a passive, self-service educational resource (MedlinePlus) with an active resource (NoteAid) where definitions are provided to the user for medical concepts that the system identifies. We use Amazon Mechanical Turk (AMT) to recruit individuals to complete ComprehENotes, a new test of EHR note comprehension. RESULTS: Mean scores for individuals with access to NoteAid are significantly higher than the mean baseline scores, both for raw scores (P=.008) and estimated ability (P=.02). CONCLUSIONS: In our experiments, we show that the active intervention leads to significantly higher scores on the comprehension test as compared with a baseline group with no resources provided. In contrast, there is no significant difference between the group that was provided with the passive intervention and the baseline group. Finally, we analyze the demographics of the individuals who participated in our AMT task and show differences between groups that align with the current understanding of health literacy between populations. This is the first work to show improvements in comprehension using tools such as NoteAid as measured by an EHR note comprehension assessment tool as opposed to patient self-reported scores

    Designing evanescent optical interactions to control the expression of Casimir forces in optomechanical structures

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    We propose an optomechanical structure consisting of a photonic-crystal (holey) membrane suspended above a layered silicon-on-insulator substrate in which resonant bonding/antibonding optical forces created by externally incident light from above enable all-optical control and actuation of stiction effects induced by the Casimir force. In this way, one can control how the Casimir force is expressed in the mechanical dynamics of the membrane, not by changing the Casimir force directly but by optically modifying the geometry and counteracting the mechanical spring constant to bring the system in or out of regimes where Casimir physics dominate. The same optical response (reflection spectrum) of the membrane to the incident light can be exploited to accurately measure the effects of the Casimir force on the equilibrium separation of the membrane

    Targeting tumor multicellular aggregation through IGPR-1 inhibits colon cancer growth and improves chemotherapy

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    Adhesion to extracellular matrix (ECM) is crucially important for survival of normal epithelial cells as detachment from ECM triggers specific apoptosis known as anoikis. As tumor cells lose the requirement for anchorage to ECM, they rely on cell-cell adhesion 'multicellular aggregation' for survival. Multicellular aggregation of tumor cells also significantly determines the sensitivity of tumor cells to the cytotoxic effects of chemotherapeutics. In this report, we demonstrate that expression of immunoglobulin containing and proline-rich receptor-1 (IGPR-1) is upregulated in human primary colon cancer. Our study demonstrates that IGPR-1 promotes tumor multicellular aggregation, and interfering with its adhesive function inhibits multicellular aggregation and, increases cell death. IGPR-1 supports colon carcinoma tumor xenograft growth in mouse, and inhibiting its activity by shRNA or blocking antibody inhibits tumor growth. More importantly, IGPR-1 regulates sensitivity of tumor cells to the chemotherapeutic agent, doxorubicin/adriamycin by a mechanism that involves doxorubicin-induced AKT activation and phosphorylation of IGPR-1 at Ser220. Our findings offer novel insight into IGPR-1's role in colorectal tumor growth, tumor chemosensitivity, and as a possible novel anti-cancer target.Grant support from: R01 CA175382/CA/NCI NIH HHS/United States, R21 CA191970/CA/NCI NIH HHS/United States, and R21 CA193958/CA/NCI NIH HHS/United State

    AIRBODS: Findings and guidance for airborne infection resilience, A publication of Airborne Infection Reduction through Building Operation and Design for SARS-CoV-2 (AIRBODS)

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    This guidance provides insights into airborne infection risks and proposes mitigation measures to improve airborne infection resilience of indoor and semi-outdoor spaces. In some poorly-ventilated and/or highly occupied spaces, the provision of increased ventilation performance can be the key to reducing airborne infection risk down to 'acceptable' (although currently undefined)levels. This is a complex area of study with many areas of uncertainty that form the basis of ongoing research. That said, the AIRBODS programme, in the context of the global research efforts associated with the COVID-19 pandemic, has generated a sound basis for improving airborne infection resilience. Key aspects of the guide with its many recommendations include: • Experiments carried out in a test chamber showing how screens can improve or, even, worsen airborne infection risk. • Field studies undertaken as part of the Events Research Programmewhichunderpinned the opening up of the UK hospitality sector in the summer of 2021. Good practice advice is provided on how to drive high-resolution CO2 and microbiological studies and then appropriately interpret results. • Analyticalmodelswere developed to understand how infection risk, using a mass balance approach with many different parameters, might be mitigated in some circumstances when compared to reference spaces. These models were then developed into a 'full building' tool which can be downloaded as part of this guidance. • Computational fluid dynamics (CFD) models were developed to provide insights into the physics of droplets or aerosols at microscale. Following completion of a test chamber validation exercise, models were developed to investigate breathing or coughing mannequins at single human moving towards audience or crowd scale. Local ventilation effectiveness and associated airborne infection risk aspects of some real spaces may significantly differ from assumed 'fully-mixed' equivalent spaces. This, along with a number of other issues, will form part of ongoing research activities. • Focus groups were also used to provide some wider context and support some of our recommendations. AIRBODS has produced a repository of data and modelling methods with the mindset of enabling building professionals to inform their design and operation decisions towards improving airborne infection resilience in their buildings

    Towards measurable resilience: A novel framework tool for the assessment of resilience levels in slums

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    This paper investigates the need for a generic technique to be applied in the assessment of resilience-related projects in slums – particularly for localised infrastructure at a community level – and proposes a novel framework tool for this purpose. The paper outlines the development of the framework tool, as well as its pilot testing on the Kenya Slum Upgrading Programme in Kibera, Nairobi. The evaluation demonstrates an improvement in asset base, capacities and external resources for the community post intervention. The lack of land tenure was identified to be a key weakness and factor which impacted resilience of the local residents

    Kinematics of subluminous O and B stars by surface helium abundance

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    The majority of hot subdwarf stars are low-mass core-helium-burning stars. Their atmospheres are generally helium deficient; however, a minority have extremely helium-rich surfaces. An additional fraction have an intermediate surface-helium abundance, occasionally accompanied by peculiar abundances of other elements. We have identified a sample of 88 hot subdwarfs including 38 helium-deficient, 27 intermediate-helium and 23 extreme-helium stars for which radial-velocity and proper-motion measurements, together with distances, allow a calculation of galactic space velocities. We have investigated the kinematics of these three groups to determine whether they belong to similar or different Galactic populations. The majority of helium-deficient subdwarfs in our sample show a kinematic distribution similar to that of thick disc stars. Helium-rich sdBs show a more diverse kinematic distribution. Although the majority are probably disc stars, a minority show a much higher velocity dispersion consistent with membership of a Galactic halo population. Several of the halo subdwarfs are members of the class of ‘heavy-metal’ subdwarfs discovered by Naslim et al

    Using mechanistic Bayesian networks to identify downstream targets of the Sonic Hedgehog pathway

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    Background: The topology of a biological pathway provides clues as to how a pathway operates, but rationally using this topology information with observed gene expression data remains a challenge. Results: We introduce a new general-purpose analytic method called Mechanistic Bayesian Networks (MBNs) that allows for the integration of gene expression data and known constraints within a signal or regulatory pathway to predict new downstream pathway targets. The MBN framework is implemented in an open-source Bayesian network learning package, the Python Environment for Bayesian Learning (PEBL). We demonstrate how MBNs can be used by modeling the early steps of the sonic hedgehog pathway using gene expression data from different developmental stages and genetic backgrounds in mouse. Using the MBN approach we are able to automatically identify many of the known downstream targets of the hedgehog pathway such as Gas1 and Gli1, along with a short list of likely targets such as Mig12. Conclusions: The MBN approach shown here can easily be extended to other pathways and data types to yield a more mechanistic framework for learning genetic regulatory models.Molecular and Cellular BiologyStem Cell and Regenerative Biolog
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