Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. Within the US LHC Accelerator Research Program (LARP) and the European FP7 HiLumi LHC Design Study, we are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.Comment: 24 pages, 1 table, 10 figure

Editorial: New frontiers in pancreatic cancer care: Multidisciplinary approaches, the role of Pancreas Units, and their organizational impacts

N

LEVERAGE, COST OF CAPITAL AND BANK VALUATION

In this paper, we present a model that demonstrates the e®ect of debt on cost of capital and value in the case of banking ¯rms. Using a static partial equilibrium setting, both in a steady state and steady growth scenario, we derive a bank-speci¯c valuation metric which separately attributes value to assets and debt cash °ows in the form of a liquidity premium and taxshield. We run our model on a sample of the largest 26 European banks from 2003 to 2016 ¯nding that the value contribution of debt bene¯ts to enterprise value is large and persistent. Further from our model, we derived an implied cost of capital (ICC) measure ¯nding consistent results with capital asset pricing model (CAPM). The theoretical framework we present is helpful to address bank debt bene¯ts valuation and to reconcile equity and asset side approaches

High Prevalence of Pain Sensitization in Knee Osteoarthritis: A Meta-Analysis with Meta-Regression

Objective The aim of this meta-analysis was to study the evidence on pain sensitization in knee osteoarthritis (OA), providing a quantitative synthesis of its prevalence and impact. Factors associated with pain sensitization were also investigated. Methods Meta-analysis; PubMed (MEDLINE), Cochrane Central Register (CENTRAL), and Web of Science were searched on February 2021. Level I to level IV studies evaluating the presence of pain sensitization in patients with symptomatic knee OA, documented through a validated method (questionnaires or quantitative sensory testing), were included. The primary outcome was the prevalence of pain sensitization. Factors influencing the prevalence were also evaluated, as well as differences in terms of pain thresholds between knee OA patients and healthy controls. Results Fifty-three articles including 7,117 patients were included. The meta-analysis of proportion documented a prevalence of pain sensitization of 20% (95% confidence interval [CI] = 16%-26%) with a significant heterogeneity of results (I-2 = 89%, P < 0.001). The diagnostic tool used was the main factor influencing the documented prevalence of pain sensitization (P = 0.01). Knee OA patients presented higher pain sensitivity compared with healthy controls, both in terms of local pressure pain threshold (standardized mean difference [SMD] = -1.00, 95% CI = -1.67 to -0.32, P = 0.007) and distant pressure pain threshold (SMD = -0.54, 95% CI = -0.76 to -0.31, P < 0.001). Conclusions Knee OA pain presents features that are consistent with a significant degree of pain sensitization. There is a high heterogeneity in the reported results, mainly based on the diagnostic tool used. The identification of the best methods to detect pain sensitization is warranted to correctly evaluate and manage symptoms of patients affected by knee OA. Registration: PROSPERO CRD42019123347

Erratum to: A Serpent/OpenFOAM coupling for 3D burnup analysis

n/

Integrated Robot Motion and Process control for manufacturing reshaping

The future of metal manufacturing processes like laser cutting, welding, and additive manufacturing shall rely on intelligent systems spearheaded by Industry 4.0. Such a digital innovation is indeed driving machinery builders to a profound transformation. From custom machines designed and optimized for a specific process, the ambition is to exploit the openness and the large availability of industrial robots to increase flexibility and reconfigurability of multi processes implementations. The challenge is that machinery builders transform themselves into high-knowledge specialized process-driven robot integrators, able to optimize the robot motion with the process controller leveraging on intelligent sensing and cognition. The work describes the multi-annual collaboration of the BLM group and Politecnico di Milano, with the support of CNR, focused on the deployment of a complete working robotic workstation characterized by the full integration of the robot control and motion planning with manufacturing processes

Loss of glial fibrillary acidic protein (GFAP) impairs Schwann cell proliferation and delays nerve regeneration after damage

Axonal loss causes disabling and permanent deficits in many peripheral neuropathies, and may result from inefficient nerve regeneration due to a defective relationship between Schwann cells, axons and the extracellular matrix. These interactions are mediated by surface receptors and transduced by cytoskeletal molecules. We investigated whether peripheral nerve regeneration is perturbed in mice that lack glial fibrillary acidic protein (GFAP), a Schwann-cell-specific cytoskeleton constituent upregulated after damage. Peripheral nerves develop and function normally in GFAP-null mice. However, axonal regeneration after damage was delayed. Mutant Schwann cells maintained the ability to dedifferentiate but showed defective proliferation, a key event for successful nerve regeneration. We also showed that GFAP and the other Schwann-cell-intermediate filament vimentin physically interact in two distinct signaling pathways involved in proliferation and nerve regeneration. GFAP binds integrin αvβ8, which initiates mitotic signals soon after damage by interacting with fibrin. Consistently, ERK phosphorylation was reduced in crushed GFAP-null nerves. Vimentin instead binds integrin α5β1, which regulates proliferation and differentiation later in regeneration, and may compensate for the absence of GFAP in mutant mice. GFAP might contribute to form macro-complexes to initiate mitogenic and differentiating signaling for efficient nerve regeneration

Increased expression of Myosin binding protein H in the skeletal muscle of amyotrophic lateral sclerosis patients

AbstractAmyotrophic lateral sclerosis (ALS) is a severe and fatal neurodegenerative disease of still unknown pathogenesis. Recent findings suggest that the skeletal muscle may play an active pathogenetic role. To investigate ALS's pathogenesis and to seek diagnostic markers, we analyzed skeletal muscle biopsies with the differential expression proteomic approach. We studied skeletal muscle biopsies from healthy controls (CN), sporadic ALS (sALS), motor neuropathies (MN) and myopathies (M). Pre-eminently among several differentially expressed proteins, Myosin binding protein H (MyBP-H) expression in ALS samples was anomalously high. MyBP-H is a component of the thick filaments of the skeletal muscle and has strong affinity for myosin, but its function is still unclear. High MyBP-H expression level was associated with abnormal expression of Rho kinase 2 (ROCK2), LIM domain kinase 1 (LIMK1) and cofilin2, that might affect the actin–myosin interaction. We propose that MyBP-H expression level serves, as a putative biomarker in the skeletal muscle, to discriminate ALS from motor neuropathies, and that it signals the onset of dysregulation in actin–myosin interaction; this in turn might contribute to the pathogenesis of ALS