2,177 research outputs found
Synchrotron Emission from Dark Matter in Galactic Subhalos. A Look into the Smith Cloud
One of the key predictions of the WIMP paradigm for Dark Matter (DM) is that
DM particles can annihilate into charged particles. These annihilations will
proceed in e.g. Galactic subhalos such as dwarf Galaxies or, as recently
pointed out, high velocity clouds such as the "Smith Cloud". In this note, we
focus on the radio emission associated with DM annihilations into electrons and
positrons occurring in the Smith Cloud. The phenomenology of this emission is
discussed in quite some detail. We argue that the uncertainties in the
propagation can be captured by the typical diffusion-loss length parameter
(Syrovatskii variable) but that the angle-integrated radio fluxes are
independent of the propagation. We conclude that if the Smith Cloud is indeed
dominated by DM, radio signals from DM annihilation stand out amongst other
messengers. Furthermore, low frequencies such as the ones observed by e.g. the
Low Frequency Array (LOFAR) and the next-generation Square Kilometre Array
(SKA) are optimal for searches for DM in the Smith Cloud. As a practical
application, we set conservative constraints on dark matter annihilation cross
section using data of continuum radio emission from the Galaxy at 22 MHz and at
1.4 GHz. Stronger constraints could be reached by background subtraction,
exploiting the profile and frequency dependence of the putative DM signal. We
set stronger but tentative limits using the median noise in brightness
temperature from the Green Bank Telescope and the LOFAR sensitivities.Comment: 23 pages, 17 figures. Extended discussion on how the limits/forecasts
are obtained. Matches published versio
Choppy Waters
The movement toward a uniform standard for confidentiality in mediation among the states is one that from the outset casts off into choppy waters, marked by pitching cross-currents of remarkable force
Major Step Forward: Proposed Uniform Mediation Act Goes Public for Comments
The move toward a simplified and uniform law for mediation takes an important step forward this summer, with the release of the first integrated draft of the proposed Uniform Mediation Act. The act is being drafted by cooperating committees of the American Bar Association Section of Dispute Resolution and the National Conference of Commissioners on Uniform State Laws. If enacted and adopted uniformly, it would replace the hundreds of pages of complex and often conflicting statutes across the country with a few short pages of simple, accessible, and helpful rules
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Bisphosphonate inhibits the expression of cyclin A2 at the transcriptional level in normal human oral keratinocytes.
Nitrogen-containing bisphosphonates (N-BPs) are the most widely used anti-resorptive agents in the treatment of bone-related diseases. N-BPs inhibit bone resorption by specifically targeting osteoclasts, bone-resorbing cells. However, soft tissue toxicity, such as oral or gastrointestinal (GI) ulcerations has frequently been reported in N-BP users, suggesting that N-BPs may also directly target cells other than osteoclasts. Previously, we reported that BPs inhibit proliferation without inducing the apoptosis of normal human oral keratinocytes (NHOKs). However, the molecular mechanisms through which N-BPs inhibit the proliferation of NHOKs are not yet fully understood. In this study, we performed gene expression profiling in N-BP-treated NHOKs and identified cyclin A2 as one of the most commonly downregulated genes. When the NHOKs were treated with N-BPs, we found that the level of cyclin A2 was suppressed in a dose- and time-dependent manner. In addition, the protein level of cyclin A2 was also significantly lower in oral epithelial cells in N-BP-treated oral mucosal tissue constructs. Cyclin A2 promoter reporter assay revealed that N-BPs inhibited the luciferase activity, indicating that the inhibition of cyclin A2 expression occurs at the transcriptional level. Furthermore, N-BPs did not alter the expression of cyclin A2 in normal human oral fibroblasts (NHOFs), suggesting that the effect of N-BPs on cyclin A2 expression may be cell-type specific. Thus, the findings of our study demonstrate that the inhibition of NHOK proliferation by N-BPs is mediated, at least in part, by the suppression of cyclin A2 expression at the transcriptional level, which may explain the underlying mechanisms of soft tissue toxicity by N-BPs
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Periodontitis-induced systemic inflammation exacerbates atherosclerosis partly via endothelial-mesenchymal transition in mice.
Growing evidence suggests close associations between periodontitis and atherosclerosis. To further understand the pathological relationships of these associations, we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g. LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals. The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis, systemic inflammation, and atherosclerosis. Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas, but mice receiving ligature or ligature/P.g. LPS showed severe periodontitis, systemic inflammation, and aortic plaque formation. The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers. The severity of periodontitis was slightly higher in mice receiving ligature/P.g. LPS than ligature alone, and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g. LPS. These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis. In vitro, P.g. LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells. Moreover, secretory proteins, such as TNF-α, from macrophages induced endothelial-mesenchymal transitions of the endothelial cells. Taken together, systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via, in part, causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice
Kinetics and Mechanism of Oxidation of N-acetyl-d-penicillamine in Acidified Iodate and Aqueous Iodine
The oxidation of the biologically-active thiol, N-acetyl-d-penicillamine (NDPen) by acidified iodate and aqueous iodine has been studied. The stoichiometry of the reaction is 1:1 in which the thiol (RSH) is oxidized to its sulfonic acid (RSO3H) without cleavage of the C-S bond. In excess acidified iodate the reaction displayed a short induction period, followed by formation of aqueous iodine. Overall stoichiometry in excess iodate was 6:5: 6 IO3 –+5RSH+6H+→5 RSO3H+3I2(aq)+3H2O. The direct reaction of aqueous iodine and was relatively fast, over within 100 ms and had a stoichiometry of 1:3: 3 I2(aq) + RSH+3H2O →RSO3H+6 I– + 6 H+. The reaction is essentially diffusion-controlled and our stopped-flow with a mixing time limitation of 1.00 ms could only catch the reaction of the last iodine molecule. This reaction is, however, strongly inhibited by the product of reaction, I– . This is due to the formation of the relatively inert triiodide anion: I2(aq)+I–→I3 –. Mass spectrometry results showed that the reaction proceeds through the sulfinic acid with negligible stabilization of the sulfenic acid. In excess of reductant, the dimeric species is the favoured product due to a rapid condensation-type reaction between the electrophilic unstable sulfenic acid and unreacted thiol.Keywords: Biological thiols, bioactivation, oxidations, oxyhalogen chemistry
Testing for entanglement with periodic coarse-graining
Continuous variables systems find valuable applications in quantum
information processing. To deal with an infinite-dimensional Hilbert space, one
in general has to handle large numbers of discretized measurements in tasks
such as entanglement detection. Here we employ the continuous transverse
spatial variables of photon pairs to experimentally demonstrate novel
entanglement criteria based on a periodic structure of coarse-grained
measurements. The periodization of the measurements allows for an efficient
evaluation of entanglement using spatial masks acting as mode analyzers over
the entire transverse field distribution of the photons and without the need to
reconstruct the probability densities of the conjugate continuous variables.
Our experimental results demonstrate the utility of the derived criteria with a
success rate in entanglement detection of relative to studied
cases.Comment: V1: revtex4, 10 pages, 4 figures + supp. material (4 pages, 1 figure)
V2: Substantial revisions implemented both in theory and experimental data
analysi
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