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Integrating Murine Gene Expression Studies to Understand Obstructive Lung Disease due to Chronic Inhaled Endotoxin
Rationale: Endotoxin is a near ubiquitous environmental exposure that that has been associated with both asthma and chronic obstructive pulmonary disease (COPD). These obstructive lung diseases have a complex pathophysiology, making them difficult to study comprehensively in the context of endotoxin. Genome-wide gene expression studies have been used to identify a molecular snapshot of the response to environmental exposures. Identification of differentially expressed genes shared across all published murine models of chronic inhaled endotoxin will provide insight into the biology underlying endotoxin-associated lung disease. Methods: We identified three published murine models with gene expression profiling after repeated low-dose inhaled endotoxin. All array data from these experiments were re-analyzed, annotated consistently, and tested for shared genes found to be differentially expressed. Additional functional comparison was conducted by testing for significant enrichment of differentially expressed genes in known pathways. The importance of this gene signature in smoking-related lung disease was assessed using hierarchical clustering in an independent experiment where mice were exposed to endotoxin, smoke, and endotoxin plus smoke. Results: A 101-gene signature was detected in three murine models, more than expected by chance. The three model systems exhibit additional similarity beyond shared genes when compared at the pathway level, with increasing enrichment of inflammatory pathways associated with longer duration of endotoxin exposure. Genes and pathways important in both asthma and COPD were shared across all endotoxin models. Mice exposed to endotoxin, smoke, and smoke plus endotoxin were accurately classified with the endotoxin gene signature. Conclusions: Despite the differences in laboratory, duration of exposure, and strain of mouse used in three experimental models of chronic inhaled endotoxin, surprising similarities in gene expression were observed. The endotoxin component of tobacco smoke may play an important role in disease development
Optical and ultraviolet spectroscopic analysis of SN 2011fe at late times
We present optical spectra of the nearby Type Ia supernova SN 2011fe at 100,
205, 311, 349, and 578 days post-maximum light, as well as an ultraviolet
spectrum obtained with Hubble Space Telescope at 360 days post-maximum light.
We compare these observations with synthetic spectra produced with the
radiative transfer code PHOENIX. The day +100 spectrum can be well fit with
models which neglect collisional and radiative data for forbidden lines.
Curiously, including this data and recomputing the fit yields a quite similar
spectrum, but with different combinations of lines forming some of the stronger
features. At day +205 and later epochs, forbidden lines dominate much of the
optical spectrum formation; however, our results indicate that recombination,
not collisional excitation, is the most influential physical process driving
spectrum formation at these late times. Consequently, our synthetic optical and
UV spectra at all epochs presented here are formed almost exclusively through
recombination-driven fluorescence. Furthermore, our models suggest that the
ultraviolet spectrum even as late as day +360 is optically thick and consists
of permitted lines from several iron-peak species. These results indicate that
the transition to the "nebular" phase in Type Ia supernovae is complex and
highly wavelength-dependent.Comment: 22 pages, 21 figuress, 1 table, submitted to MNRA
Scientific Opportunities with an X-ray Free-Electron Laser Oscillator
An X-ray free-electron laser oscillator (XFELO) is a new type of hard X-ray
source that would produce fully coherent pulses with meV bandwidth and stable
intensity. The XFELO complements existing sources based on self-amplified
spontaneous emission (SASE) from high-gain X-ray free-electron lasers (XFEL)
that produce ultra-short pulses with broad-band chaotic spectra. This report is
based on discussions of scientific opportunities enabled by an XFELO during a
workshop held at SLAC on June 29 - July 1, 2016Comment: 21 pages, 12 figure
New Mass and Radius Constraints on the LHS 1140 Planets -- LHS 1140 b is Either a Temperate Mini-Neptune or a Water World
The two-planet transiting system LHS 1140 has been extensively observed since
its discovery in 2017, notably with , HST, TESS, and ESPRESSO, placing
strong constraints on the parameters of the M4.5 host star and its small
temperate exoplanets, LHS 1140 b and c. Here, we reanalyse the ESPRESSO
observations of LHS 1140 with the novel line-by-line framework designed to
fully exploit the radial velocity content of a stellar spectrum while being
resilient to outlier measurements. The improved radial velocities, combined
with updated stellar parameters, consolidate our knowledge on the mass of LHS
1140 b (5.600.19 M) and LHS 1140 c (1.910.06 M)
with unprecedented precision of 3%. Transits from , HST, and TESS are
jointly analysed for the first time, allowing us to refine the planetary radii
of b (1.7300.025 R) and c (1.2720.026 R).
Stellar abundance measurements of refractory elements (Fe, Mg and Si) obtained
with NIRPS are used to constrain the internal structure of LHS 1140 b. This
planet is unlikely to be a rocky super-Earth as previously reported, but rather
a mini-Neptune with a 0.1% H/He envelope by mass or a water world with a
water-mass fraction between 9 and 19% depending on the atmospheric composition
and relative abundance of Fe and Mg. While the mini-Neptune case would not be
habitable, a water-abundant LHS 1140 b potentially has habitable surface
conditions according to 3D global climate models, suggesting liquid water at
the substellar point for atmospheres with relatively low CO concentration,
from Earth-like to a few bars.Comment: 31 pages, 18 figures, accepted for publication in ApJ
SN 2019ehk: A Double-peaked Ca-rich Transient with Luminous X-Ray Emission and Shock-ionized Spectral Features
We present panchromatic observations and modeling of the Calcium-rich supernova (SN) 2019ehk in the star-forming galaxy M100 (d â 16.2 Mpc) starting 10 hr after explosion and continuing for ~300 days. SN 2019ehk shows a double-peaked optical light curve peaking at t = 3 and 15 days. The first peak is coincident with luminous, rapidly decaying Swift-XRTâdiscovered X-ray emission (L_x â 10âŽÂč erg sâ»Âč at 3 days; L_x â tâ»Âł), and a Shane/Kast spectral detection of narrow Hα and He II emission lines (v â 500 km sâ»Âč) originating from pre-existent circumstellar material (CSM). We attribute this phenomenology to radiation from shock interaction with extended, dense material surrounding the progenitor star at r (0.1â1) Ă 10Âčâ· cm. The photometric and spectroscopic properties during the second light-curve peak are consistent with those of Ca-rich transients (rise-time of t_r = 13.4 ± 0.210 days and a peak B-band magnitude of M_B = â15.1 ± 0.200 mag). We find that SN 2019ehk synthesized (3.1 ± 0.11) Ă 10â»ÂČ M_â of â”â¶Ni and ejected M_(ej) = (0.72 ± 0.040) Mâ total with a kinetic energy E_k = (1.8 ± 0.10) Ă 10â”â° erg. Finally, deep HST pre-explosion imaging at the SN site constrains the parameter space of viable stellar progenitors to massive stars in the lowest mass bin (~10 M_â) in binaries that lost most of their He envelope or white dwarfs (WDs). The explosion and environment properties of SN 2019ehk further restrict the potential WD progenitor systems to low-mass hybrid HeCO WD+CO WD binaries
Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq
We present optical, infrared, ultraviolet, and radio observations of SN
2022xkq, an underluminous fast-declining type Ia supernova (SN Ia) in NGC 1784
( Mpc), from to 180 days after explosion. The
high-cadence observations of SN 2022xkq, a photometrically transitional and
spectroscopically 91bg-like SN Ia, cover the first days and weeks following
explosion which are critical to distinguishing between explosion scenarios. The
early light curve of SN 2022xkq has a red early color and exhibits a flux
excess which is more prominent in redder bands; this is the first time such a
feature has been seen in a transitional/91bg-like SN Ia. We also present 92
optical and 19 near-infrared (NIR) spectra, beginning 0.4 days after explosion
in the optical and 2.6 days after explosion in the NIR. SN 2022xkq exhibits a
long-lived C I 1.0693 m feature which persists until 5 days post-maximum.
We also detect C II 6580 in the pre-maximum optical spectra. These
lines are evidence for unburnt carbon that is difficult to reconcile with the
double detonation of a sub-Chandrasekhar mass white dwarf. No existing
explosion model can fully explain the photometric and spectroscopic dataset of
SN 2022xkq, but the considerable breadth of the observations is ideal for
furthering our understanding of the processes which produce faint SNe Ia.Comment: 38 pages, 16 figures, accepted for publication in ApJ, the figure 15
input models and synthetic spectra are now available at
https://zenodo.org/record/837925
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