543 research outputs found

    Hypothesis:soluble Aβ oligomers in association with redox-active metal ions are the optimal generators of reactive oxygen species in Alzheimer's disease

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    Considerable evidence points to oxidative stress in the brain as an important event in the early stages of Alzheimer's disease (AD). The transition metal ions of Cu, Fe, and Zn are all enriched in the amyloid cores of senile plaques in AD. Those of Cu and Fe are redox active and bind to Aβ in vitro. When bound, they can facilitate the reduction of oxygen to hydrogen peroxide, and of the latter to the hydroxyl radical. This radical is very aggressive and can cause considerable oxidative damage. Recent research favours the involvement of small, soluble oligomers as the aggregating species responsible for Aβ neurotoxicity. We propose that the generation of reactive oxygen species (i.e., hydrogen peroxide and hydroxyl radicals) by these oligomers, in association with redox-active metal ions, is a key molecular mechanism underlying the pathogenesis of AD and some other neurodegenerative disorders

    Implementing radial basis function neural networks in pulsed analogue VLSI

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    Multiple safety net regulators and agency problems in the European Union: Is prompt corrective action partly the solution?

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    This paper discusses the institutional changes needed in Europe if prompt corrective action (PCA) is to be effective in supervising and resolving cross-border banking groups. The paper identifies these changes starting with enhancements in the availability of information on banking groups’ financial condition to prudential supervisors. Next, the paper considers the collective decision making by prudential supervisors with authority to make discretionary decisions within the PCA framework as soon as a bank in a cross-border banking group falls below the minimum capital standard. Finally, the paper analyzes the coordination measures that should be implemented if PCA requires the bank to be resolved.

    Multiple safety net regulators and agency problems in the EU: is Prompt Corrective Action a partial solution?

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    Prompt Corrective Action (PCA) provides a more efficient mechanism for dealing with problem banks operating in more than one European country. In a PCA framework, a bank’s losses are likely to be substantially reduced. This reduction in the losses to deposit insurance and governments will improve the problem of allocating those losses across the various insurance schemes and make it less likely that any deposit insurer will renege on its obligations in a cross-border banking crisis. This paper explores the institutional changes needed in Europe if PCA is to be effective in resolving the cross-border agency problems that arise in supervising and resolving cross-border banking groups. The paper identifies these changes starting with enhancements in the availability to prudential supervisors of information on banking groups’ financial condition. Next, the paper considers collective decision-making by prudential supervisors with authority to make discretionary decisions within the PCA framework as soon as a bank of a cross-border banking group falls below the minimum capital standard. Finally, the paper analyses the coordination measures that should be implemented if PCA requires the bank to be resolved.banking supervision; European Union; Prompt Corrective Action

    Extended 1D Method for Coherent Synchrotron Radiation including Shielding

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    Coherent Synchrotron Radiation can severely limit the performance of accelerators designed for high brightness and short bunch length. Examples include light sources based on ERLs or FELs, and bunch compressors for linear colliders. In order to better simulate Coherent Synchrotron Radiation, the established 1-dimensional formalism is extended to work at lower energies, at shorter bunch lengths, and for an arbitrary configuration of multiple bends. Wide vacuum chambers are simulated by means of vertical image charges. This formalism has been implemented in the general beam dynamics code "Bmad" and its results are here compared to analytical approximations, to numerical solutions of the Maxwell equations, and to the simulation code "elegant"

    Microplastic ingestion ubiquitous in marine turtles

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    Despite concerns regarding the environmental impacts of microplastics, knowledge of the incidence and levels of synthetic particles in large marine vertebrates is lacking. Here, we utilize an optimized enzymatic digestion methodology, previously developed for zooplankton, to explore whether synthetic particles could be isolated from marine turtle ingesta. We report the presence of synthetic particles in every turtle subjected to investigation (n = 102) which included individuals from all seven species of marine turtle, sampled from three ocean basins (Atlantic [ATL]: n = 30, four species; Mediterranean (MED): n = 56, two species; Pacific (PAC): n = 16, five species). Most particles (n = 811) were fibres (ATL: 77.1% MED: 85.3% PAC: 64.8%) with blue and black being the dominant colours. In lesser quantities were fragments (ATL: 22.9%: MED: 14.7% PAC: 20.2%) and microbeads (4.8%; PAC only; to our knowledge the first isolation of microbeads from marine megavertebrates). Fourier transform infrared spectroscopy (FT‐IR) of a subsample of particles (n = 169) showed a range of synthetic materials such as elastomers (MED: 61.2%; PAC: 3.4%), thermoplastics (ATL: 36.8%: MED: 20.7% PAC: 27.7%) and synthetic regenerated cellulosic fibres (SRCF; ATL: 63.2%: MED: 5.8% PAC: 68.9%). Synthetic particles being isolated from species occupying different trophic levels suggest the possibility of multiple ingestion pathways. These include exposure from polluted seawater and sediments and/or additional trophic transfer from contaminated prey/forage items. We assess the likelihood that microplastic ingestion presents a significant conservation problem at current levels compared to other anthropogenic threats

    Applying Innovative Technologies and Practices in the Rapid Shift to Remote Learning

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    Shifting to remote learning during times of a crisis, such as the COVID-19 pandemic, is very different from well-planned online learning. This paper highlights the experience of shifting to remote learning and outlines lessons learned from the experience. The COVID-19 pandemic brought a wholly new educational context, which uncovered problems such as; course delivery & assessment; communication & misinformation; and technology limitations. This highlights a gap in research on rapid mid-term shift to remote learning in times of a crisis. There are plenty of resources for Information Systems education to draw lessons for effective online learning practices. However, there is limited research on remote learning in response to a crisis, such as COVID-19. This paper presents a case study at Bournemouth University, in which a Business Systems Analysis and Design (BSAD) course was moved to remote learning during COVID-19. The results reflect on the importance of learning focus, students focus, and learning resource focus for remote learning. This includes activities to promote effective communication and information resources, student engagement and support, and remote course delivery and assessment. All these activities are essential elements in a rapid shift from blended learning to remote learning during a crisis, such as COVID-19

    The relationship between redox enzyme activity and electrochemical potential—cellular and mechanistic implications from protein film electrochemistry

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    In protein film electrochemistry a redox protein of interest is studied as an electroactive film adsorbed on an electrode surface. For redox enzymes this configuration allows quantification of the relationship between catalytic activity and electrochemical potential. Considered as a function of enzyme environment, i.e., pH, substrate concentration etc., the activity–potential relationship provides a fingerprint of activity unique to a given enzyme. Here we consider the nature of the activity–potential relationship in terms of both its cellular impact and its origin in the structure and catalytic mechanism of the enzyme. We propose that the activity–potential relationship of a redox enzyme is tuned to facilitate cellular function and highlight opportunities to test this hypothesis through computational, structural, biochemical and cellular studies

    Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries

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    We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0030.0031 GeV2^2. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q2Q^2=10 GeV2^2. The polarised uu valence quark distribution, Δuv(x)\Delta u_v(x), is positive and the polarisation increases with xx. The polarised dd valence quark distribution, Δdv(x)\Delta d_v(x), is negative and the non-strange sea distribution, Δqˉ(x)\Delta \bar q(x), is consistent with zero over the measured range of xx. We find for the first moments 01Δuv(x)dx=0.77±0.10±0.08\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08, 01Δdv(x)dx=0.52±0.14±0.09\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09 and 01Δqˉ(x)dx=0.01±0.04±0.03\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03, where we assumed Δuˉ(x)=Δdˉ(x)\Delta \bar u(x) = \Delta \bar d(x). We also determine for the first time the second moments of the valence distributions 01xΔqv(x)dx\int_0^1 x \Delta q_v(x) dx.Comment: 17 page
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