Tailoring the pressure-drop in multi-layered open-cell porous inconel structures

This study investigates the pressure-drop behaviour associated with airflow through bulk and structurally tailored multi-layered, open-cell porous Inconel structures over a wide airflow velocity range (0–50 m s-1). The effect of airflow velocity on the pressure-drop behaviour as a function of the sample thickness is presented and related to the flow behaviour corresponding to the relevant flow regimes (Darcy, Forchheimer, Turbulent and Postturbulent). Entrance effects are highlighted as a source of the pressure-drop increase for porous structures with air gaps, regardless of their sizes, as long as they are larger than those generated by loosely-stacked structures. The pressure-drops for gapped porous structures and the mathematical-summation of the pressure drop for the corresponding individual components, were in very good agreement, at lower airflow velocities. The potential for mass-efficient porous structures, providing a high pressure drop, was demonstrated using multiple thin porous laminates separated by air gaps

Physics Behind Precision

This document provides a writeup of contributions to the FCC-ee mini-workshop on "Physics behind precision" held at CERN, on 2-3 February 2016.Comment: https://indico.cern.ch/event/469561

Network-mediated encoding of circadian time: The suprachiasmatic nucleus (SCN) from genes to neurons to circuits, and back

The transcriptional architecture of intracellular circadian clocks is similar across phyla, but in mammals interneuronal mechanisms confer a higher level of circadian integration. The suprachiasmatic nucleus (SCN) is a unique model to study these mechanisms, as it operates as a ∼24 h clock not only in the living animal, but also when isolated in culture. This “clock in a dish” can be used to address fundamental questions, such as how intraneuronal mechanisms are translated by SCN neurons into circuit-level emergent properties and how the circuit decodes, and responds to, light input. This review addresses recent developments in understanding the relationship between electrical activity, [Ca(2+)](i), and intracellular clocks. Furthermore, optogenetic and chemogenetic approaches to investigate the distinct roles of neurons and glial cells in circuit encoding of circadian time will be discussed, as well as the epigenetic and circuit-level mechanisms that enable the SCN to translate light input into coherent daily rhythms

The littlest Higgs model and Higgs boson associated production with top quark pair at high energy linear e+e−e^{+}e^{-} collider

In the parameter space allowed by the electroweak precision measurement data, we consider the contributions of the new particles predicted by the littlest Higgs($LH$) model to the Higgs boson associated production with top quark pair in the future high energy linear $e^{+}e^{-}$ collider($ILC$). We find that the contributions mainly come from the new gauge bosons $Z_{H}$ and $B_{H}$. For reasonable values of the free parameters, the absolute value of the relative correction parameter $\delta\sigma/\sigma^{SM}$ can be significanly large, which might be observed in the future $ILC$ experiment with $\sqrt{S}=800GeV$.Comment: latex files, 13 pages, 3 figure

Flavor changing scalar couplings and tγ(Z)t\gamma(Z) production at hadron colliders

We calculate the contributions of the flavor changing scalar ($FCS$) couplings arised from topcolor-assisted technicolor ($TC2$) models at tree-level to the $t\gamma$ and $tZ$ production at the Tevatron and $LHC$ experiments. We find that the production cross sections are very small at the Tevatron with $\sqrt{s}=1.96TeV$, which is smaller than 5 fb in most of the parameter space of $TC2$ models. However, the virtual effects of the $FCS$ couplings on the $t\gamma(Z)$ production can be easily detected at the $LHC$ with $\sqrt{s}=14TeV$ via the final state $\gamma l\bar{\nu}b$ ($l^{+}l^{-}l\bar{\nu}b$).Comment: 10 pages,5 figure

Simulating the High Energy Gamma-ray sky seen by the GLAST Large Area Telescope

This paper presents the simulation of the GLAST high energy gamma-ray telescope. The simulation package, written in C++, is based on the Geant4 toolkit, and it is integrated into a general framework used to process events. A detailed simulation of the electronic signals inside Silicon detectors has been provided and it is used for the particle tracking, which is handled by a dedicated software. A unique repository for the geometrical description of the detector has been realized using the XML language and a C++ library to access this information has been designed and implemented. A new event display based on the HepRep protocol was implemented. The full simulation was used to simulate a full week of GLAST high energy gamma-ray observations. This paper outlines the contribution developed by the Italian GLAST software group.Comment: 6 pages, 4 figures, to be published in the Proceedings of the 6th International Symposium ''Frontiers of Fundamental and Computational Physics'' (FFP6), Udine (Italy), Sep. 26-29, 200

TLR7-mediated skin inflammation remotely triggers chemokine expression and leukocyte accumulation in the brain

Background: The relationship between the brain and the immune system has become increasingly topical as, although it is immune-specialised, the CNS is not free from the influences of the immune system. Recent data indicate that peripheral immune stimulation can significantly affect the CNS. But the mechanisms underpinning this relationship remain unclear. The standard approach to understanding this relationship has relied on systemic immune activation using bacterial components, finding that immune mediators, such as cytokines, can have a significant effect on brain function and behaviour. More rarely have studies used disease models that are representative of human disorders. Methods: Here we use a well-characterised animal model of psoriasis-like skin inflammation—imiquimod—to investigate the effects of tissue-specific peripheral inflammation on the brain. We used full genome array, flow cytometry analysis of immune cell infiltration, doublecortin staining for neural precursor cells and a behavioural read-out exploiting natural burrowing behaviour. Results: We found that a number of genes are upregulated in the brain following treatment, amongst which is a subset of inflammatory chemokines (CCL3, CCL5, CCL9, CXCL10, CXCL13, CXCL16 and CCR5). Strikingly, this model induced the infiltration of a number of immune cell subsets into the brain parenchyma, including T cells, NK cells and myeloid cells, along with a reduction in neurogenesis and a suppression of burrowing activity. Conclusions: These findings demonstrate that cutaneous, peripheral immune stimulation is associated with significant leukocyte infiltration into the brain and suggest that chemokines may be amongst the key mediators driving this response

Proceedings of the Workshop on Monte Carlo's, Physics and Simulations at the LHC PART II

These proceedings collect the presentations given at the first three meetings of the INFN "Workshop on Monte Carlo's, Physics and Simulations at the LHC", held at the Frascati National Laboratories in 2006. The first part of these proceedings contains pedagogical introductions to several basic topics of both theoretical and experimental high pT LHC physics. The second part collects more specialised presentations.Comment: 157 pages, 136 figures; contribution by M. Grazzini has been adde

The RNA m6A Reader YTHDF2 Is Essential for the Post-transcriptional Regulation of the Maternal Transcriptome and Oocyte Competence.

YTHDF2 binds and destabilizes N6-methyladenosine (m6A)-modified mRNA. The extent to which this branch of m6A RNA-regulatory pathway functions in vivo and contributes to mammalian development remains unknown. Here we find that YTHDF2 deficiency is partially permissive in mice and results in female-specific infertility. Using conditional mutagenesis, we demonstrate that YTHDF2 is autonomously required within the germline to produce MII oocytes that are competent to sustain early zygotic development. Oocyte maturation is associated with a wave of maternal RNA degradation, and the resulting relative changes to the MII transcriptome are integral to oocyte quality. The loss of YTHDF2 results in the failure to regulate transcript dosage of a cohort of genes during oocyte maturation, with enrichment observed for the YTHDF2-binding consensus and evidence of m6A in these upregulated genes. In summary, the m6A-reader YTHDF2 is an intrinsic determinant of mammalian oocyte competence and early zygotic development

Identifying Ligand Binding Conformations of the β2-Adrenergic Receptor by Using Its Agonists as Computational Probes

Recently available G-protein coupled receptor (GPCR) structures and biophysical studies suggest that the difference between the effects of various agonists and antagonists cannot be explained by single structures alone, but rather that the conformational ensembles of the proteins need to be considered. Here we use an elastic network model-guided molecular dynamics simulation protocol to generate an ensemble of conformers of a prototypical GPCR, β2-adrenergic receptor (β2AR). The resulting conformers are clustered into groups based on the conformations of the ligand binding site, and distinct conformers from each group are assessed for their binding to known agonists of β2AR. We show that the select ligands bind preferentially to different predicted conformers of β2AR, and identify a role of β2AR extracellular region as an allosteric binding site for larger drugs such as salmeterol. Thus, drugs and ligands can be used as "computational probes" to systematically identify protein conformers with likely biological significance. © 2012 Isin et al