Naresuan University Journal
Not a member yet
39887 research outputs found
Sort by
Spatial receptive fields in the retina and dorsal lateral geniculate nucleus of mice lacking rods and cones
No full textIn advanced retinal degeneration loss of rods and cones leaves melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) as the only source of visual information. ipRGCs drive non-image-forming responses (e.g., circadian photoentrainment) under such conditions but, despite projecting to the primary visual thalamus [dorsal lateral geniculate nucleus (dLGN)], do not support form vision. We wished to determine what precludes ipRGCs supporting spatial discrimination after photoreceptor loss, using a mouse model (rd/rd cl) lacking rods and cones. Using multielectrode arrays, we found that both RGCs and neurons in the dLGN of this animal have clearly delineated spatial receptive fields. In the retina, they are typically symmetrical, lack inhibitory surrounds, and have diameters in the range of 10–30° of visual space. Receptive fields in the dLGN were larger (diameters typically 30–70°) but matched the retinotopic map of the mouse dLGN. Injections of a neuroanatomical tracer (cholera toxin β-subunit) into the dLGN confirmed that retinotopic order of ganglion cell projections to the dLGN and thalamic projections to the cortex is at least superficially intact in rd/rd cl mice. However, as previously reported for deafferented ipRGCs, onset and offset of light responses have long latencies in the rd/rd cl retina and dLGN. Accordingly, dLGN neurons failed to track dynamic changes in light intensity in this animal. Our data reveal that ipRGCs can convey spatial information in advanced retinal degeneration and identify their poor temporal fidelity as the major limitation in their ability to provide information about spatial patterns under natural viewing conditions.<br/
A comparison of the causes of FY1 and FY2 Trainees' prescribing errors: A Preliminary Analysis
No full textTurning Radiotherapy into an Effective Systemic Anti-Cancer Treatment in Combination with Immunotherapy
No full textNote: Establishing alpha-particle radiation damage experiments using the Dalton Cumbrian Facility's 5 MV tandem pelletron
No full textEvaluating the radiation stability of mineral phases is a vital research challenge when assessing the performance of the materials employed in a Geological Disposal Facility for radioactive waste. This report outlines the setup and methodology for efficiently allowing the determination of the dose dependence of damage to a mineral from a single ion irradiated sample. The technique has been deployed using the Dalton Cumbrian Facility's 5 MV tandem pelletron to irradiate a suite of minerals with a controlled alpha-particle (He-4(2+)) beam. Such minerals are proxies for near-field clay based buffer material surrounding radioactive canisters, as well as the sorbent components of the host rock. (C) 2015 AIP Publishing LLC
‘Six Versus Twelve Sessions of Hypnotherapy for Irritable Bowel Syndrome: A Randomised, Controlled, Single Blind Non-Inferiority Trial’
No full textPolymer scaffold with preferential parallel grooves enhance nerve regeneration.
No full textWe have modified the surface topography of poly ε-caprolactone (PCL) and poly lactic acid (PLA) blended films to improve cell proliferation and to guide the regeneration of peripheral nerves. Films with differing shaped grooves were made using patterned silicon templates: sloped walls (SL), V-shaped (V) and square shaped (SQ), and compared to non-grooved surfaces with micro-pits. The solvent cast films were tested in vitro using adult adipose derived stem cells differentiated to Schwann cell-like cells (dASC). Cell attachment, proliferation and cell orientation were all improved on the grooved surfaces, with SL grooves giving the best results. We present in vivo data on Sprague Dawley rat sciatic nerve injury with 10mm gap, evaluating nerve regeneration at 3 weeks across a polymer nerve conduit modified with intra-luminal grooves (SL, V and SQ) and differing wall thickness (70, 100, 120 and 210 μm). The SL grooved nerve conduit showed a significant improvement over the other topographical shaped grooves, whilst increasing the conduit wall thickness saw no positive effect on the biological response of the regenerating nerve. Furthermore, the preferred SL grooved conduit (C) with 70μm wall thickness was compared to current clinical gold standard of autologous nerve graft (Ag) in the rat 10mm sciatic nerve gap model. At 3 weeks post-surgery, all nerve gaps across both groups were bridged with regenerated nerve fibers. At 16 weeks, features of regenerated axons were comparable between the autograft (Ag) and conduit (C) groups. End organ assessments of muscle weight, electromyography and skin reinnervation were also similar between the groups. The comparable experimental outcome between conduit and autograft, suggests that the PCL/PLA conduit with inner-lumen micro-structured grooves could be used as potential alternative treatment for peripheral nerve repair
Symmetry Improved 2PI Effective Action and the Infrared Divergences of the Standard Model
No full textResummations of infinite sets of higher-order perturbative contributions are often needed both in thermal field theory and at zero temperature. For instance, the behaviour of the Standard Model (SM) effective potential extrapolated to very high energies is known to be extremely sensitive to higher-order effects. The 2PI effective action provides a systematic approach to consistently perform such resummations. However, one of its major limitations was that its loopwise expansion introduces residual violations of possible global symmetries, thus giving rise to massive Goldstone bosons in the spontaneously broken phase of the theory. We review the recently developed symmetry-improved 2PI formalism for consistently encoding global symmetries in the 2PI approach, and discuss its satisfactory field-theoretical properties. We then apply the formalism to study the infrared divergences of the SM effective potential due to Goldstone bosons, which may affect the stability analyses of the SM. We present quantitative comparisons, for the scalar sector of the SM, with the approximate partial resummation procedure recently developed to address this problem, and show the quantitative discrepancy of the latter with the more complete 2PI approach, thus motivating further studies in this direction
