834 research outputs found
Eliminating thermal infrared background noise by imaging with undetected photons
Spectroscopy and imaging in the mid-infrared ( 2.5 ” m ⌠λ ⌠25 ” m ) is bedeviled by the presence of a strong 300-K thermal background at room temperature that makes infrared (IR) detectors decades noisier than can be readily achieved in the visible. The technique of imaging with undetected photons (IUP) exploits the quantum correlations between entangled photon pairs to transfer image information from one spectral region to another, and here we show that it does so in a way that is immune to the thermal background. This means that IUP can be used to perform high-speed photon-counting measurements across the mid-IR spectrum, using uncooled visible detectors that are many times cheaper, faster, and more sensitive than their IR counterparts
Coupling undetected sensing modes by quantum erasure
The effect known as ``induced coherence without induced emission'' has
spawned a field dedicated to imaging with undetected photons (IUP), where
photons from two distinct photon-pair sources interfere if their outputs are
made indistinguishable. The indistinguishability is commonly achieved in two
setups. Induced coherence IUP (IC-IUP) has only the idler photons from the
first source passing through the second, whilst nonlinear interferometry
(NI-IUP) has both signal and idler photons from the first source passing
through the second and can be simpler to implement. In both cases, changes in
the idler path between sources can be detected by measuring the interference
fringes in the signal path in a way that allows image information to be moved
between different wavelengths. Here we model and implement a novel setup that
uses a polarization state quantum eraser approach to move continuously between
IC-IUP and NI-IUP operation. We find excellent agreement between experiment and
theory in the low-gain or quantum regime. The system also provides a new route
for optimizing IUP interference by using controllable quantum erasure to
balance the interferometer
Longevity and viability of Taenia solium eggs in the digestive system of the beetle Ammophorus rubripes
Porphyry indicator minerals and their mineral chemistry as vectoring and fertility tools
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Macrophage Subset Sensitivity to Endotoxin Tolerisation by Porphyromonas gingivalis
Macrophages (MΊs) determine oral mucosal responses; mediating tolerance to commensal microbes and food whilst maintaining the capacity to activate immune defences to pathogens. MΊ responses are determined by both differentiation and activation stimuli, giving rise to two distinct subsets; pro-inflammatory M1- and anti-inflammatory/regulatory M2- MΊs. M2-like subsets predominate tolerance induction whereas M1 MΊs predominate in inflammatory pathologies, mediating destructive inflammatory mechanisms, such as those in chronic P.gingivalis (PG) periodontal infection. MΊ responses can be suppressed to benefit either the host or the pathogen. Chronic stimulation by bacterial pathogen associated molecular patterns (PAMPs), such as LPS, is well established to induce tolerance. The aim of this study was to investigate the susceptibility of MΊ subsets to suppression by P. gingivalis. CD14hi and CD14lo M1- and M2-like MΊs were generated in vitro from the THP-1 monocyte cell line by differentiation with PMA and vitamin D3, respectively. MΊ subsets were pre-treated with heat-killed PG (HKPG) and PG-LPS prior to stimulation by bacterial PAMPs. Modulation of inflammation was measured by TNFα, IL-1ÎČ, IL-6, IL-10 ELISA and NFÎșB activation by reporter gene assay. HKPG and PG-LPS differentially suppress PAMP-induced TNFα, IL-6 and IL-10 but fail to suppress IL-1ÎČ expression in M1 and M2 MΊs. In addition, P.gingivalis suppressed NFÎșB activation in CD14lo and CD14hi M2 regulatory MΊs and CD14lo M1 MΊs whereas CD14hi M1 pro-inflammatory MΊs were refractory to suppression. In conclusion, P.gingivalis selectively tolerises regulatory M2 MΊs with little effect on pro-inflammatory CD14hi M1 MΊs; differential suppression facilitating immunopathology at the expense of immunity
The Cosmology of Composite Inelastic Dark Matter
Composite dark matter is a natural setting for implementing inelastic dark
matter - the O(100 keV) mass splitting arises from spin-spin interactions of
constituent fermions. In models where the constituents are charged under an
axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark
matter scatters inelastically off Standard Model nuclei and can explain the
DAMA/LIBRA annual modulation signal. This article describes the early Universe
cosmology of a minimal implementation of a composite inelastic dark matter
model where the dark matter is a meson composed of a light and a heavy quark.
The synthesis of the constituent quarks into dark mesons and baryons results in
several qualitatively different configurations of the resulting dark matter
hadrons depending on the relative mass scales in the system.Comment: 31 pages, 4 figures; references added, typos correcte
Vaccines against periodontitis: a forward-looking review
Periodontal disease, as a polymicrobial disease, is globally endemic as well as being a global epidemic. It is the leading cause for tooth loss in the adult population and has been positively related to life-threatening systemic diseases such as atherosclerosis and diabetes. As a result, it is clear that more sophisticated therapeutic modalities need to be developed, which may include vaccines. Up to now, however, no periodontal vaccine trial has been successful in satisfying all the requirements; to prevent the colonization of a multiple pathogenic biofilm in the subgingival area, to elicit a high level of effector molecules such as immunoglobulin sufficient to opsonize and phagocytose the invading organisms, to suppress the induced alveolar bone loss, or to stimulate helper T-cell polarization that exerts cytokine functions optimal for protection against bacteria and tissue destruction. This article reviews all the vaccine trials so as to construct a more sophisticated strategy which may be relevant in the future. As an innovative strategy to circumvent these barriers, vaccine trials to stimulate antigen-specific T-cells polarized toward helper T-cells with a regulatory phenotype (Tregs, CD4+, CD25+, FoxP3+) have also been introduced. Targeting not only a single pathogen, but polymicrobial organisms, and targeting not only periodontal disease, but also periodontal disease-triggered systemic disease could be a feasible goal
Population Structure as Revealed by mtDNA and Microsatellites in Northern Fur Seals, Callorhinus ursinus, throughout Their Range
Background: The northern fur seal (Callorhinus ursinus; NFS) is a widely distributed pinniped that has been shown to exhibit a high degree of philopatry to islands, breeding areas on an island, and even to specific segments of breeding areas. This level of philopatry could conceivably lead to highly genetically divergent populations. However, northern fur seals have the potential for dispersal across large distances and have experienced repeated rapid population expansions following glacial retreat and the more recent cessation of intensive harvest pressure. Methodology/Principal Findings: Using microsatellite and mitochondrial loci, we examined population structure in NFS throughout their range. We found only weak population genetic structure among breeding islands including significant FST and W ST values between eastern and western Pacific islands. Conclusions: We conclude that insufficient time since rapid population expansion events (both post glacial and following the cessation of intense harvest pressure) mixed with low levels of contemporary migration have resulted in an absence of genetic structure across the entire northern fur seal range
Porphyromonas gingivalis suppresses adaptive immunity in periodontitis, atherosclerosis and Alzheimerâs disease
Porphyromonas gingivalis, a keystone pathogen in chronic periodontitis, has been found to associate with remote body organ inflammatory pathologies including atherosclerosis and Alzheimerâs disease (AD). Although P. gingivalis has a plethora of virulence factors, much of its pathogenicity is surprisingly related to the overall immunosuppression of the host. This review focuses on P. gingivalis aiding suppression of the hostâs adaptive immune system involving manipulation of cellular immunological responses specifically T- and B-cells in periodontitis and related conditions. In periodontitis this bacterium inhibits the synthesis of IL-2 and increases humoral responses. This reduces inflammatory responses related to T- and B-cell activation, and subsequent IFN-É€ secretion by a subset of T cells. The T cells further suppresses upregulation of programmed cell death-1 (PD-1)-receptor on CD+-cells and its ligand PD-L1 on CD11b+- subset of T-cells. IL-2 down-regulates immune response-regulated genes, induces a cytokine pattern in which the Th17 lineage is favored thereby modulating the Th17/ T-regulatory cell (Treg) imbalance. The suppression of IFN-É€ stimulated release of interferon-inducible protein-10 (IP-10) chemokine ligands [ITAC (CXCL11) and Mig (CXCL9)] by P. gingivalis capsular serotypes, triggers distinct T-cell responses, and contributes to local immune evasion by release of its outer membrane vesicles. In atherosclerosis P. gingivalis reduces Tregs and transforming growth factor beta-1 (TGF-1) and causes imbalance in the Th17 lineage of the Treg population. In Alzheimerâs disease P. gingivalis may affect the blood-brain barrier permeability, and inhibit local IFN-É€ response by preventing entry of immune cells into the brain. The scarcity of adaptive immune cells in Alzheimerâs disease neuropathology implies P. gingivalis infection of the brain likely causes impaired clearance of insoluble amyloid and induces immunosuppression. By the effective manipulation of the armory of adaptive immune suppression through a plethora of virulence factors P. gingivalis may act as a keystone organism in periodontitis and in related systemic diseases and other remote body inflammatory pathologies
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
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