The magnesium alloy AZ91 was hot rolled and annealed to produce a plate with a strong basal texture. The resultant plate was mechanically tested in five different test orientations in the ...solution-treated, underaged, peak-aged and overaged conditions. The critical resolved shear stresses for activation of basal slip, prismatic slip and twinning were then estimated for each of the ageing conditions. We found that the age hardening of the slip systems is consistent with Orowan hardening, but that this theory significantly underestimates the hardening of the
{
1
0
1
¯
2
}
twin system. It is proposed that back stresses and hardening of the slip systems that accommodate twinning also contribute to precipitate hardening of the twin system.
We calculate the contribution to the muon anomalous magnetic moment hadronic vacuum polarization from the connected diagrams of up and down quarks, omitting electromagnetism. We employ QCD ...gauge-field configurations with dynamical u, d, s, and c quarks and the physical pion mass, and analyze five ensembles with lattice spacings ranging from a≈0.06 to 0.15 fm. The up- and down-quark masses in our simulations have equal masses ml. We obtain, in this world where all pions have the mass of the π0, 1010aμll(conn.)=637.8(8.8), in agreement with independent lattice-QCD calculations. We then combine this value with published lattice-QCD results for the connected contributions from strange, charm, and bottom quarks, and an estimate of the uncertainty due to the fact that our calculation does not include strong-isospin breaking, electromagnetism, or contributions from quark-disconnected diagrams. Our final result for the total O(α2) hadronic-vacuum polarization to the muon's anomalous magnetic moment is 1010aμHVP,LO=699(15)u,d(1)s,c,b, where the errors are from the light-quark and heavy-quark contributions, respectively. Our result agrees with both ab-initio lattice-QCD calculations and phenomenological determinations from experimental e+e−-scattering data. It is 1.3σ below the "no new physics" value of the hadronic-vacuum-polarization contribution inferred from combining the BNL E821 measurement of aμ with theoretical calculations of the other contributions.
Abstract Since the launch in 2008 by the National Osteoporosis Guideline Group (NOGG), of guidance for the diagnosis and management of osteoporosis in postmenopausal women and older men in the UK ...there have been significant advances in risk assessment and treatment. These have been incorporated into an updated version of the guideline, with an additional focus on the management of glucocorticoid-induced osteoporosis, the role of calcium and vitamin D therapy and the benefits and risks of long-term bisphosphonate therapy. The updated guideline is summarised below. The recommendations in the guideline are intended to aid management decisions but do not replace the need for clinical judgement in the care of individuals in clinical practice.
Dendritic spines serve as preferential sites of excitatory synaptic connections and are pleomorphic. To address the structure-function relationship of the dendritic spines, we used two-photon ...uncaging of glutamate to allow mapping of functional glutamate receptors at the level of the single synapse. Our analyses of the spines of CA1 pyramidal neurons reveal that AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)-type glutamate receptors are abundant (up to 150/spine) in mushroom spines but sparsely distributed in thin spines and filopodia. The latter may be serving as the structural substrates of the silent synapses that have been proposed to play roles in development and plasticity of synaptic transmission. Our data indicate that distribution of functional AMPA receptors is tightly correlated with spine geometry and that receptor activity is independently regulated at the level of single spines.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Here, we discuss the question of whether or not inflationary spacetimes can be geodesically complete in the infinite past. Geodesic completeness is a necessary condition for averting an initial ...singularity during eternal inflation. It is frequently argued that cosmological models which are expanding sufficiently fast (having average Hubble expansion rate Havg > 0) must be incomplete in null and timelike past directions. This well-known conjecture relies on specific bounds on the integral of the Hubble parameter over a past- directed timelike or null geodesic. As stated, we show this claim is an open issue. We show that the calculation of Havg yields a continuum of results for a given spacetime predicated upon the underlying topological assumptions. We present an improved definition for Havg and introduce an uncountably infinite cohort of cosmological solutions which are geodesically complete despite having Havg > 0. We discuss a standardized definition for inflationary spacetimes as well as quantum (semiclassical) cosmological concerns over physically reasonable scale factors.
After an overview of major scientific discoveries of the 18th and 19th centuries, which created electrical science as we know and understand it and led to its useful applications in energy ...conversion, transmission, manufacturing industry and communications, this Circuits and Systems History book fills a gap in published literature by providing a record of the many outstanding scientists, mathematicians and engineers who laid the foundations of Circuit Theory and Filter Design from the mid-20th Century. Additionally, the book records the history of the IEEE Circuits and Systems Society from its origins as the small Circuit Theory Group of the Institute of Radio Engineers (IRE), which merged with the American Institute of Electrical Engineers (AIEE) to form IEEE in 1963, to the large and broad-coverage worldwide IEEE Society which it is today. Many authors from many countries contributed to the creation of this book, working to a very tight time-schedule. The result is a substantial contribution to their enthusiasm and expertise which it is hoped that readers will find both interesting and useful. It is sure that in such a book omissions will be found and in the space and time available, much valuable material had to be left out. It is hoped that this book will stimulate an interest in the marvellous heritage and contributions that have come from the many outstanding people who worked in the Circuits and Systems area.
The linear ubiquitin chain assembly complex (LUBAC) is a RING E3 ligase that regulates immune and inflammatory signalling pathways. Unlike classical RING E3 ligases, LUBAC determines the type of ...ubiquitin chain being formed, an activity normally associated with the E2 enzyme. We show that the RING‐in‐between‐RING (RBR)‐containing region of HOIP—the catalytic subunit of LUBAC—is sufficient to generate linear ubiquitin chains. However, this activity is inhibited by the N‐terminal portion of the molecule, an inhibition that is released upon complex formation with HOIL‐1L or SHARPIN. Furthermore, we demonstrate that HOIP transfers ubiquitin to the substrate through a thioester intermediate formed by a conserved cysteine in the RING2 domain, supporting the notion that RBR ligases act as RING/HECT hybrids.
The N‐terminus of the LUBAC catalytic subunit is shown to be autoinhibitory and counteracted by the other subunits of the complex. Linear ubiquitination proceeds through a thioesther intermediate, indicative of a RING/HECT hybrid mechanism.
We are currently witnessing transformative change for people with cystic fibrosis with the introduction of small molecule, mutation-specific drugs capable of restoring function of the defective ...protein, cystic fibrosis transmembrane conductance regulator (CFTR). However, despite being a single gene disorder, there are multiple cystic fibrosis-causing genetic variants; mutation-specific drugs are not suitable for all genetic variants and also do not correct all the multisystem clinical manifestations of the disease. For many, there will remain a need for improved treatments. Those patients with gene variants responsive to CFTR modulators may have found these therapies to be transformational; research is now focusing on safely reducing the burden of symptom-directed treatment. However, modulators are not available in all parts of the globe, an issue which is further widening existing health inequalities. For patients who are not suitable for- or do not have access to- modulator drugs, alternative approaches are progressing through the trials pipeline. There will be challenges encountered in design and implementation of these trials, for which the established global CF infrastructure is a major advantage. Here, the Cystic Fibrosis National Research Strategy Group of the UK NIHR Respiratory Translational Research Collaboration looks to the future of cystic fibrosis therapies and consider priorities for future research and development.
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