85 research outputs found
SN 2007od: A Type IIP SN with Circumstellar Interaction
SN 2007od exhibits characteristics that have rarely been seen in a Type IIP
supernova (SN). Optical V band photometry reveals a very steep brightness
decline between the plateau and nebular phases of ~4.5 mag, likely due to SN
2007od containing a low mass of 56Ni. The optical spectra show an evolution
from normal Type IIP with broad Halpha emission, to a complex, four component
Halpha emission profile exhibiting asymmetries caused by dust extinction after
day 232. This is similar to the spectral evolution of the Type IIn SN 1998S,
although no early-time narrow (~200 km s-1) Halpha component was present in SN
2007od. In both SNe, the intermediate-width Halpha emission components are
thought to arise in the interaction between the ejecta and its circumstellar
medium (CSM). SN 2007od also shows a mid-IR excess due to new dust. The
evolution of the Halpha profile and the presence of the mid-IR excess provide
strong evidence that SN 2007od formed new dust before day 232. Late-time
observations reveal a flattening of the visible lightcurve. This flattening is
a strong indication of the presence of a light echo, which likely accounts for
much of the broad, underlying Halpha component seen at late-times. We believe
the multi-peaked Halpha emission is consistent with the interaction of the
ejecta with a circumstellar ring or torus (for the inner components at \pm1500
km s-1), and a single blob or cloud of circumstellar material out of the plane
of the CSM ring (for the outer component at -5000 km s-1). The most probable
location for the formation of new dust is in the cool dense shell created by
the interaction between the expanding ejecta and its CSM. Monte Carlo radiative
transfer modeling of the dust emission from SN 2007od implies that up to 4x
10-4Msun of new dust has formed. This is similar to the amounts of dust formed
in other CCSNe such as SNe 1999em, 2004et, and 2006jc.Comment: 35 pages, 6 figures. Accepted for publication in Ap
The effects of dust on the optical and infrared evolution of SN 2004et
We present an analysis of multi-epoch observations of the Type II-P supernova
SN 2004et. New and archival optical spectra of SN 2004et are used to study the
evolution of the Halpha and [O I] 6300A line profiles between days 259 and 646.
Mid-infrared imaging was carried out between 2004 to 2010. We include Spitzer
`warm' mission photometry at 3.6 and 4.5um obtained on days 1779, 1931 and
2151, along with ground-based and HST optical and near-infrared observations
obtained between days 79 and 1803. Multi-wavelength light curves are presented,
as well as optical-infrared spectral energy distributions (SEDs) for multiple
epochs. Starting from about day 300, the optical light curves provide evidence
for an increasing amount of circumstellar extinction attributable to newly
formed dust, with the additional extinction reaching 0.8-1.5 magnitudes in the
V-band by day 690. The overall SEDs were fitted with multiple blackbody
components, in order to investigate the luminosity evolution of the supernova,
and then with Monte Carlo radiative transfer models using smooth or clumpy dust
distributions, in order to estimate how much new dust condensed in the ejecta.
The luminosity evolution was consistent with the decay of 56Co in the ejecta up
until about day 690, after which an additional emission source is required, in
agreement with the findings of Kotak et al. (2009). Clumped dust density
distributions consisting of 20% amorphous carbons and 80% silicates by mass
were able to match the observed optical and infrared SEDs, with dust masses
that increased from 8x10^{-5} Msun on day 300 to 1.5x10^{-3} Msun on day 690,
still significantly lower than the values needed for core collapse supernovae
to make a significant contribution to the dust enrichment of galaxies.Comment: 24 pages, 12 figures, 9 tables, published in MNRA
Inflammation causes remodeling of mitochondrial cytochrome c oxidase mediated by the bifunctional gene C15orf48
Dysregulated mitochondrial function is a hallmark of immune-mediated inflammatory diseases. Cytochrome c oxidase (CcO), which mediates the rate-limiting step in mitochondrial respiration, is remodeled during development and in response to changes of oxygen availability, but there has been little study of CcO remodeling during inflammation. Here, we describe an elegant molecular switch mediated by the bifunctional transcript C15orf48, which orchestrates the substitution of the CcO subunit NDUFA4 by its paralog C15ORF48 in primary macrophages. Expression of C15orf48 is a conserved response to inflammatory signals and occurs in many immune-related pathologies. In rheumatoid arthritis, C15orf48 mRNA is elevated in peripheral monocytes and proinflammatory synovial tissue macrophages, and its expression positively correlates with disease severity and declines in remission. C15orf48 is also expressed by pathogenic macrophages in severe coronavirus disease 2019 (COVID-19). Study of a rare metabolic disease syndrome provides evidence that loss of the NDUFA4 subunit supports proinflammatory macrophage functions
Laser capture microdissection in forensic research: a review
In forensic sciences, short tandem repeat (STR) analysis has become the prime tool for DNA-based identification of the donor(s) of biological stains and/or traces. Many traces, however, contain cells and, hence, DNA, from more than a single individual, giving rise to mixed genotypes and the subsequent difficulties in interpreting the results. An even more challenging situation occurs when cells of a victim are much more abundant than the cells of the perpetrator. Therefore, the forensic community seeks to improve cell-separation methods in order to generate single-donor cell populations from a mixed trace in order to facilitate DNA typing and identification. Laser capture microdissection (LCM) offers a valuable tool for precise separation of specific cells. This review summarises all possible forensic applications of LCM, gives an overview of the staining and detection options, including automated detection and retrieval of cells of interest, and reviews the DNA extraction protocols compatible with LCM of cells from forensic samples
Dust in Supernovae and Supernova Remnants I : Formation Scenarios
Supernovae are considered as prime sources of dust in space. Observations of local supernovae over the past couple of decades have detected the presence of dust in supernova ejecta. The reddening of the high redshift quasars also indicate the presence of large masses of dust in early galaxies. Considering the top heavy IMF in the early galaxies, supernovae are assumed to be the major contributor to these large amounts of dust. However, the composition and morphology of dust grains formed in a supernova ejecta is yet to be understood with clarity. Moreover, the dust masses inferred from observations in mid-infrared and submillimeter wavelength regimes differ by two orders of magnitude or more. Therefore, the mechanism responsible for the synthesis of molecules and dust in such environments plays a crucial role in studying the evolution of cosmic dust in galaxies. This review summarises our current knowledge of dust formation in supernova ejecta and tries to quantify the role of supernovae as dust producers in a galaxy.Peer reviewe
Multidisciplinary investigations of the diets of two post-medieval populations from London using stable isotopes and microdebris analysis
This paper presents the first multi-tissue study of diet in post-medieval London using both the stable light isotope analysis of carbon and nitrogen and analysis of microdebris in dental calculus. Dietary intake was explored over short and long timescales. Bulk bone collagen was analysed from humans from the Queen’s Chapel of the Savoy (QCS) (n = 66) and the St Barnabas/St Mary Abbots (SB) (n = 25). Incremental dentine analysis was performed on the second molar of individual QCS1123 to explore childhood dietary intake. Bulk hair samples (n = 4) were sampled from adults from QCS, and dental calculus was analysed from four other individuals using microscopy. In addition, bone collagen from a total of 46 animals from QCS (n = 11) and the additional site of Prescot Street (n = 35) was analysed, providing the first animal dietary baseline for post-medieval London. Overall, isotopic results suggest a largely C3-based terrestrial diet for both populations, with the exception of QCS1123 who exhibited values consistent with the consumption of C4 food sources throughout childhood and adulthood. The differences exhibited in δ15Ncoll across both populations likely reflect variations in diet due to social class and occupation, with individuals from SB likely representing wealthier individuals consuming larger quantities of animal and marine fish protein. Microdebris analysis results were limited but indicate the consumption of domestic cereals. This paper demonstrates the utility of a multidisciplinary approach to investigate diet across long and short timescales to further our understanding of variations in social status and mobility
Production of dust by massive stars at high redshift
The large amounts of dust detected in sub-millimeter galaxies and quasars at
high redshift pose a challenge to galaxy formation models and theories of
cosmic dust formation. At z > 6 only stars of relatively high mass (> 3 Msun)
are sufficiently short-lived to be potential stellar sources of dust. This
review is devoted to identifying and quantifying the most important stellar
channels of rapid dust formation. We ascertain the dust production efficiency
of stars in the mass range 3-40 Msun using both observed and theoretical dust
yields of evolved massive stars and supernovae (SNe) and provide analytical
expressions for the dust production efficiencies in various scenarios. We also
address the strong sensitivity of the total dust productivity to the initial
mass function. From simple considerations, we find that, in the early Universe,
high-mass (> 3 Msun) asymptotic giant branch stars can only be dominant dust
producers if SNe generate <~ 3 x 10^-3 Msun of dust whereas SNe prevail if they
are more efficient. We address the challenges in inferring dust masses and
star-formation rates from observations of high-redshift galaxies. We conclude
that significant SN dust production at high redshift is likely required to
reproduce current dust mass estimates, possibly coupled with rapid dust grain
growth in the interstellar medium.Comment: 72 pages, 9 figures, 5 tables; to be published in The Astronomy and
Astrophysics Revie
A communal catalogue reveals Earth’s multiscale microbial diversity
Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity
A communal catalogue reveals Earth's multiscale microbial diversity
Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe
Clinical and molecular consequences of disease-associated de novo mutations in SATB2
Purpose: To characterize features associated with de novo mutations affecting SATB2 function in individuals ascertained on the basis of intellectual disability. Methods: Twenty previously unreported individuals with 19 different SATB2 mutations (11 loss-of-function and 8 missense variants) were studied. Fibroblasts were used to measure mutant protein production. Subcellular localization and mobility of wild-type and mutant SATB2 were assessed using fluorescently tagged protein. Results: Recurrent clinical features included neurodevelopmental impairment (19/19), absent/near absent speech (16/19), normal somatic growth (17/19), cleft palate (9/19), drooling (12/19), and dental anomalies (8/19). Six of eight missense variants clustered in the first CUT domain. Sibling recurrence due to gonadal mosaicism was seen in one family. A nonsense mutation in the last exon resulted in production of a truncated protein retaining all three DNA-binding domains. SATB2 nuclear mobility was mutation-dependent; p.Arg389Cys in CUT1 increased mobility and both p.Gly515Ser in CUT2 and p.Gln566Lys between CUT2 and HOX reduced mobility. The clinical features in individuals with missense variants were indistinguishable from those with loss of function. Conclusion: SATB2 haploinsufficiency is a common cause of syndromic intellectual disability. When mutant SATB2 protein is produced, the protein appears functionally inactive with a disrupted pattern of chromatin or matrix association
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