1,242 research outputs found
Anti-Inflammatory Effects of Pomegranate Peel Extracts on In Vitro Human Intestinal Caco-2 Cells and Ex Vivo Porcine Colonic Tissue Explants
Ultraviolet Diversity of Type Ia Supernovae
Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the
outermost layers of the explosion, and UV spectra of SNe Ia are expected to be
extremely sensitive to differences in progenitor composition and the details of
the explosion. Here we present the first study of a sample of high
signal-to-noise ratio SN Ia spectra that extend blueward of 2900 A. We focus on
spectra taken within 5 days of maximum brightness. Our sample of ten SNe Ia
spans the majority of the parameter space of SN Ia optical diversity. We find
that SNe Ia have significantly more diversity in the UV than in the optical,
with the spectral variance continuing to increase with decreasing wavelengths
until at least 1800 A (the limit of our data). The majority of the UV variance
correlates with optical light-curve shape, while there are no obvious and
unique correlations between spectral shape and either ejecta velocity or
host-galaxy morphology. Using light-curve shape as the primary variable, we
create a UV spectral model for SNe Ia at peak brightness. With the model, we
can examine how individual SNe vary relative to expectations based on only
their light-curve shape. Doing this, we confirm an excess of flux for SN 2011fe
at short wavelengths, consistent with its progenitor having a subsolar
metallicity. While most other SNe Ia do not show large deviations from the
model, ASASSN-14lp has a deficit of flux at short wavelengths, suggesting that
its progenitor was relatively metal rich.Comment: 9 pages, 6 figures, submitted to MNRA
Anti-inflammatory effects of a casein hydrolysate and its peptide-enriched fractions on TNFα-challenged Caco-2 cells and LPS-challenged porcine colonic explants
Bioactive milk peptides are reported to illicit a range of physiological benefits and have been proposed as potential functional food ingredients. The objective of this study was to characterize the anti-inflammatory properties of sodium caseinate (NaCAS), its enzyme hydrolysate (EH) and peptide-enriched fractions (5 kDa retentate [R], 1 kDaR and 1 kDa permeate [P]), both in vitro using a Caco-2 cell line, and also ex vivo using a porcine colonic tissue explant system. Caco-2 cells were stimulated with tumour necrosis factor alpha (TNFα) and co-treated with casein hydrolysates for 24 h. Following this, interleukin (IL)-8 concentrations in the supernatant were measured using enzyme-linked immunosorbent assay. Porcine colonic tissue was stimulated with lipopolysaccharide and co-treated with casein hydrolysates for 3 h. The expression of a panel of inflammatory cytokines was measured using qPCR. While dexamethasone reduced the IL-8 concentration by 41.6%, the 1 kDaR and 1 kDaP fractions reduced IL-8 by 68.7% and 66.1%, respectively, relative to TNFα-stimulated Caco-2 cells (P < 0.05). In the ex vivo system, only the 1 kDaR fraction elicited a decrease in IL1-α, IL1-β, IL-8, TGF-β and IL-10 expression (P < 0.05). This study provides evidence that the bioactive peptides present in the 1 kDaR fraction of the NaCAS hydrolysate possess anti-inflammatory properties in vitro and ex vivo. Further in vivo analysis of the anti-inflammatory properties of the 1 kDaR is proposed
High-Velocity Line Forming Regions in the Type Ia Supernova 2009ig
We report measurements and analysis of high-velocity (> 20,000 km/s) and
photospheric absorption features in a series of spectra of the Type Ia
supernova (SN) 2009ig obtained between -14d and +13d with respect to the time
of maximum B-band luminosity. We identify lines of Si II, Si III, S II, Ca II
and Fe II that produce both high-velocity (HVF) and photospheric-velocity (PVF)
absorption features. SN 2009ig is unusual for the large number of lines with
detectable HVF in the spectra, but the light-curve parameters correspond to a
slightly overluminous but unexceptional SN Ia (M_B = -19.46 mag and Delta_m15
(B) = 0.90 mag). Similarly, the Si II lambda_6355 velocity at the time of B-max
is greater than "normal" for a SN Ia, but it is not extreme (v_Si = 13,400
km/s). The -14d and -13d spectra clearly resolve HVF from Si II lambda_6355 as
separate absorptions from a detached line forming region. At these very early
phases, detached HVF are prevalent in all lines. From -12d to -6d, HVF and PVF
are detected simultaneously, and the two line forming regions maintain a
constant separation of about 8,000 km/s. After -6d all absorption features are
PVF. The observations of SN 2009ig provide a complete picture of the transition
from HVF to PVF. Most SN Ia show evidence for HVF from multiple lines in
spectra obtained before -10d, and we compare the spectra of SN 2009ig to
observations of other SN. We show that each of the unusual line profiles for Si
II lambda_6355 found in early-time spectra of SN Ia correlate to a specific
phase in a common development sequence from HVF to PVF.Comment: 19 pages, 11figures, 4 tables, submitted to Ap
Gravitational Waves From Known Pulsars: Results From The Initial Detector Era
We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom
A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007
We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at
http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
Swift follow-up observations of candidate gravitational-wave transient events
We present the first multi-wavelength follow-up observations of two candidate
gravitational-wave (GW) transient events recorded by LIGO and Virgo in their
2009-2010 science run. The events were selected with low latency by the network
of GW detectors and their candidate sky locations were observed by the Swift
observatory. Image transient detection was used to analyze the collected
electromagnetic data, which were found to be consistent with background.
Off-line analysis of the GW data alone has also established that the selected
GW events show no evidence of an astrophysical origin; one of them is
consistent with background and the other one was a test, part of a "blind
injection challenge". With this work we demonstrate the feasibility of rapid
follow-ups of GW transients and establish the sensitivity improvement joint
electromagnetic and GW observations could bring. This is a first step toward an
electromagnetic follow-up program in the regime of routine detections with the
advanced GW instruments expected within this decade. In that regime
multi-wavelength observations will play a significant role in completing the
astrophysical identification of GW sources. We present the methods and results
from this first combined analysis and discuss its implications in terms of
sensitivity for the present and future instruments.Comment: Submitted for publication 2012 May 25, accepted 2012 October 25,
published 2012 November 21, in ApJS, 203, 28 (
http://stacks.iop.org/0067-0049/203/28 ); 14 pages, 3 figures, 6 tables;
LIGO-P1100038; Science summary at
http://www.ligo.org/science/Publication-S6LVSwift/index.php ; Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p110003
Search for gravitational waves associated with the InterPlanetary Network short gamma ray bursts
We outline the scientific motivation behind a search for gravitational waves
associated with short gamma ray bursts detected by the InterPlanetary Network
(IPN) during LIGO's fifth science run and Virgo's first science run. The IPN
localisation of short gamma ray bursts is limited to extended error boxes of
different shapes and sizes and a search on these error boxes poses a series of
challenges for data analysis. We will discuss these challenges and outline the
methods to optimise the search over these error boxes.Comment: Methods paper; Proceedings for Eduardo Amaldi 9 Conference on
Gravitational Waves, July 2011, Cardiff, U
Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run
We summarize the sensitivity achieved by the LIGO and Virgo gravitational
wave detectors for compact binary coalescence (CBC) searches during LIGO's
fifth science run and Virgo's first science run. We present noise spectral
density curves for each of the four detectors that operated during these
science runs which are representative of the typical performance achieved by
the detectors for CBC searches. These spectra are intended for release to the
public as a summary of detector performance for CBC searches during these
science runs.Comment: 12 pages, 5 figure
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