9,771 research outputs found

    A simple approach for measuring FRET in fluorescent biosensors using two-photon microscopy

    Get PDF
    Genetically encoded fluorescent protein (FP)-based biosensor probes are useful tools for monitoring cellular events in living cells and tissues. Because these probes were developed for one-photon excitation approaches, their broad two-photon excitation (2PE) and poorly understood photobleaching characteristics have made their implementation in studies using two-photon laser-scanning microscopy (TPLSM) challenging. Here we describe a protocol that simplifies the use of Förster resonance energy transfer (FRET)-based biosensors in TPLSM. First, the TPLSM system is evaluated and optimized using FRET standards expressed in living cells, which enables the determination of spectral bleed-through (SBT) and the confirmation of FRET measurements from the known standards. Next, we describe how to apply the approach experimentally using a modified version of the A kinase activity reporter (AKAR) protein kinase A (PKA) biosensor as an example—first in cells in culture and then in hepatocytes in the liver of living mice. The microscopic imaging can be accomplished in a day in laboratories that routinely use TPLSM

    Avatars:the other side of Proteus's mirror : a study into avatar choice regarding perception

    Get PDF
    The trend for online interactions, can be regarded as being ‘anti-so-cially social’, meaning that a great deal of time is spent playing, working and socializing with the internet serving as the communication conduit. Within that Virtual Social Environment very deep relationships are formed and maintained without the parties ever having met each other face-to-face. Raising the question how much does the physical appearance of an avatar influence the perception of the person behind it? Are relationships informed by appearance even in the vir-tual world and what implications does that have for second language acquisition? This paper leads to a small-scale research project where a selection of avatars with various racially identifiable characteristics were used to identify which av-atars a second language speaker would feel more at ease interacting with in the target language. The resultant research aims to test three hypotheses regarding preferred avatar choice for second language users based solely on perceptions

    Fundamentals, advances and perspectives of piezocatalysis: A marriage of solid-state physics and catalytic chemistry

    Get PDF
    Piezocatalysis, an evolving catalytic technology built on the piezoelectric properties of catalysts, breaks down the barrier between mechanical energy and chemical energy. The potential difference that arises from the mechanical deformation of a piezoelectric material is commonly termed ‘piezopotential’. Piezopotential has been demonstrated to facilitate the manipulation of band structure and/or charge carrier separation. Despite significant efforts to design materials and understand the mechanism of piezoelectrically enhanced chemistry through semiconductor physics, there remains an opportunity to review the relationships between catalytic performance and piezo/ferroelectric properties. Herein, we provide a comprehensive summary of the catalytic mechanisms and correlated piezo/ferroelectric physical mechanism in the field of piezocatalysis. A fundamental understanding of piezo/ferroelectric structural design based on solid-state physics can be used to shed light on the future development of piezocatalysis. In addition, the types of piezoelectric materials, the design strategies for catalysis efficiency enhancement, and the up-to-date applications in environment remediation, renewable energy conversion, biomedicine and biotechnology are discussed. Finally, future perspectives for designing and developing highly active piezocatalysts using the guidelines of physicochemical relationships are proposed

    Bringing light into darkness: A multiple baseline mixed methods case series evaluation of Augmented Depression Therapy (ADepT)

    Get PDF
    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Two core features of depression are elevations in negative valence system (NVS) functioning and reductions in positive valence system (PVS) functioning. Existing psychological treatments have focused on the NVS and neglected the PVS, which may contribute to sub-optimal outcomes. The present mixed methods multiple randomised baseline case series preliminarily evaluates Augmented Depression Therapy (ADepT), a novel depression treatment targeting PVS and NVS disturbance that aims both to reduce depression and enhance wellbeing. Eleven clinically depressed participants were recruited. Intensive time series analyses showed that 7/11 participants improved on both wellbeing and depression. Reliable and clinically significant improvement was observed for 9/11 participants on at least one of these outcomes (and also across a range of other PVS and NVS outcomes). Group level analyses showed significant pre to post change on all outcomes. Benchmarking analyses indicated these effect sizes were at least comparable (and for some PVS outcomes superior) to existing treatments. Gains were largely sustained over one-year followup. Qualitative interviews indicated ADepT was feasible and acceptable. These findings provide preliminary support for ADepT as a novel depression treatment. Further evaluation directly comparing ADepT to existing treatments using randomised controlled trial designs is now required.National Institute for Health Research (NIHR

    Investigation of the Multiple Method Adaptive Control (MMAC) method for flight control systems

    Get PDF
    The stochastic adaptive control of the NASA F-8C digital-fly-by-wire aircraft using the multiple model adaptive control (MMAC) method is presented. The selection of the performance criteria for the lateral and the longitudinal dynamics, the design of the Kalman filters for different operating conditions, the identification algorithm associated with the MMAC method, the control system design, and simulation results obtained using the real time simulator of the F-8 aircraft at the NASA Langley Research Center are discussed

    Epitaxial (111) Films of Cu, Ni, and CuxNi_xNi_yonα−Al on {\alpha}-Al_2OO_3$(0001) for Graphene Growth by Chemical Vapor Deposition

    Full text link
    Films of (111)-textured Cu, Ni, and Cux_xNiy_y were evaluated as substrates for chemical vapor deposition of graphene. A metal thickness of 400 nm to 700 nm was sputtered onto a substrate of α−\alpha-Al2_2O3_3(0001) at temperatures of 250 C to 650 C. The films were then annealed at 1000 C in a tube furnace. X-ray and electron backscatter diffraction measurements showed all films have (111) texture but have grains with in-plane orientations differing by 60∘60^{\circ}. The in-plane epitaxial relationship for all films was [110]metal[110]_{metal}||[101ˉ0]Al2O3[10\bar{1}0]_{{Al}_{2}{O}_{3}}. Reactive sputtering of Al in O2_2 before metal deposition resulted in a single in-plane orientation over 97 % of the Ni film but had no significant effect on the Cu grain structure. Transmission electron microscopy showed a clean Ni/Al2_2O3_3 interface, confirmed the epitaxial relationship, and showed that formation of the 60∘60^{\circ} twin grains was associated with features on the Al2_2O3_3 surface. Increasing total pressure and Cu vapor pressure during annealing decreased the roughness of Cu and and Cux_xNiy_y films. Graphene grown on the Ni(111) films was more uniform than that grown on polycrystalline Ni/SiO2_2 films, but still showed thickness variations on a much smaller length scale than the distance between grains

    How to determine a quantum state by measurements: The Pauli problem for a particle with arbitrary potential

    Get PDF
    The problem of reconstructing a pure quantum state ¿¿> from measurable quantities is considered for a particle moving in a one-dimensional potential V(x). Suppose that the position probability distribution ¿¿(x,t)¿2 has been measured at time t, and let it have M nodes. It is shown that after measuring the time evolved distribution at a short-time interval ¿t later, ¿¿(x,t+¿t)¿2, the set of wave functions compatible with these distributions is given by a smooth manifold M in Hilbert space. The manifold M is isomorphic to an M-dimensional torus, TM. Finally, M additional expectation values of appropriately chosen nonlocal operators fix the quantum state uniquely. The method used here is the analog of an approach that has been applied successfully to the corresponding problem for a spin system
    • …
    corecore