92 research outputs found
Variations in the 6.2 m emission profile in starburst-dominated galaxies: a signature of polycyclic aromatic nitrogen heterocycles (PANHs)?
Analyses of the polycyclic aromatic hydrocarbon (PAH) feature profiles,
especially the 6.2 m feature, could indicate the presence of nitrogen
incorporated in their aromatic rings. In this work, 155 predominantly
starburst-dominated galaxies (including HII regions and Seyferts, for example),
extracted from the Spitzer/IRS ATLAS project (Hern\'an-Caballero &
Hatziminaoglou 2011), have their 6.2 m profiles fitted allowing their
separation into the Peeters' A, B and C classes (Peeters et al. 2002). 67% of
these galaxies were classified as class A, 31% were as class B and 2% as class
C. Currently class A sources, corresponding to a central wavelength near 6.22
m, seem only to be explained by polycyclic aromatic nitrogen heterocycles
(PANH, Hudgins et al. 2005), whereas class B may represent a mix between PAHs
and PANHs emissions or different PANH structures or ionization states.
Therefore, these spectra suggest a significant presence of PANHs in the
interstellar medium (ISM) of these galaxies that could be related to their
starburst-dominated emission. These results also suggest that PANHs constitute
another reservoir of nitrogen in the Universe, in addition to the nitrogen in
the gas phase and ices of the ISM
Comment on "Ab initio calculations of the lattice parameter and elastic stiffness coefficients of bcc Fe with solutes" Comp. Mat. Sci. v.126 pp.503-513 (2017)
In a recent paper, the authors propose to separately calculate the volumetric
and chemical contributions to the elastic stiffness coefficients of systems
containing solutes, as it is "computationally more efficient". We show that
this is not the case and further that their methodology and hence their results
are incorrect. There is no short cut for performing the desired calculations,
if done rigorously, as we show in our 2012 work
Genome-Wide Mycobacterium tuberculosis Variation (GMTV) Database: A New Tool for Integrating Sequence Variations and Epidemiology
Background
Tuberculosis (TB) poses a worldwide threat due to advancing multidrug-resistant strains and deadly co-infections with Human immunodeficiency virus. Today large amounts of Mycobacterium tuberculosis whole genome sequencing data are being assessed broadly and yet there exists no comprehensive online resource that connects M. tuberculosis genome variants with geographic origin, with drug resistance or with clinical outcome. Description
Here we describe a broadly inclusive unifying Genome-wide Mycobacterium tuberculosis Variation (GMTV) database, (http://mtb.dobzhanskycenter.org) that catalogues genome variations of M. tuberculosis strains collected across Russia. GMTV contains a broad spectrum of data derived from different sources and related to M. tuberculosis molecular biology, epidemiology, TB clinical outcome, year and place of isolation, drug resistance profiles and displays the variants across the genome using a dedicated genome browser. GMTV database, which includes 1084 genomes and over 69,000 SNP or Indel variants, can be queried about M. tuberculosis genome variation and putative associations with drug resistance, geographical origin, and clinical stages and outcomes. Conclusions
Implementation of GMTV tracks the pattern of changes of M. tuberculosis strains in different geographical areas, facilitates disease gene discoveries associated with drug resistance or different clinical sequelae, and automates comparative genomic analyses among M. tuberculosis strains
Genome-Wide Association Study Reveals a Novel Association Between MYBPC3 Gene Polymorphism, Endurance Athlete Status, Aerobic Capacity and Steroid Metabolism.
The genetic predisposition to elite athletic performance has been a controversial subject due to the underpowered studies and the small effect size of identified genetic variants. The aims of this study were to investigate the association of common single-nucleotide polymorphisms (SNPs) with endurance athlete status in a large cohort of elite European athletes using GWAS approach, followed by replication studies in Russian and Japanese elite athletes and functional validation using metabolomics analysis. The association of 476,728 SNPs of Illumina DrugCore Gene chip and endurance athlete status was investigated in 796 European international-level athletes (645 males, 151 females) by comparing allelic frequencies between athletes specialized in sports with high ( = 662) and low/moderate ( = 134) aerobic component. Replication of results was performed by comparing the frequencies of the most significant SNPs between 242 and 168 elite Russian high and low/moderate aerobic athletes, respectively, and between 60 elite Japanese endurance athletes and 406 controls. A meta-analysis has identified rs1052373 (GG homozygotes) in Myosin Binding Protein (; implicated in cardiac hypertrophic myopathy) gene to be associated with endurance athlete status ( = 1.43 × 10, odd ratio 2.2). Homozygotes carriers of rs1052373 G allele in Russian athletes had significantly greater VO than carriers of the AA + AG ( = 0.005). Subsequent metabolomics analysis revealed several amino acids and lipids associated with rs1052373 G allele (1.82 × 10) including the testosterone precursor androstenediol (3beta,17beta) disulfate. This is the first report of genome-wide significant SNP and related metabolites associated with elite athlete status. Further investigations of the functional relevance of the identified SNPs and metabolites in relation to enhanced athletic performance are warranted
No Evidence of a Common DNA Variant Profile Specific to World Class Endurance Athletes
There are strong genetic components to cardiorespiratory fitness and its
response to exercise training. It would be useful to understand the
differences in the genomic profile of highly trained endurance athletes of
world class caliber and sedentary controls. An international consortium
(GAMES) was established in order to compare elite endurance athletes and
ethnicity-matched controls in a case-control study design. Genome-wide
association studies were undertaken on two cohorts of elite endurance athletes
and controls (GENATHLETE and Japanese endurance runners), from which a panel
of 45 promising markers was identified. These markers were tested for
replication in seven additional cohorts of endurance athletes and controls:
from Australia, Ethiopia, Japan, Kenya, Poland, Russia and Spain. The study is
based on a total of 1520 endurance athletes (835 who took part in endurance
events in World Championships and/or Olympic Games) and 2760 controls. We
hypothesized that world-class athletes are likely to be characterized by an
even higher concentration of endurance performance alleles and we performed
separate analyses on this subsample. The meta-analysis of all available
studies revealed one statistically significant marker (rs558129 at GALNTL6
locus, p = 0.0002), even after correcting for multiple testing. As shown by
the low heterogeneity index (I2 = 0), all eight cohorts showed the same
direction of association with rs558129, even though p-values varied across the
individual studies. In summary, this study did not identify a panel of genomic
variants common to these elite endurance athlete groups. Since GAMES was
underpowered to identify alleles with small effect sizes, some of the
suggestive leads identified should be explored in expanded comparisons of
world-class endurance athletes and sedentary controls and in tightly
controlled exercise training studies. Such studies have the potential to
illuminate the biology not only of world class endurance performance but also
of compromised cardiac functions and cardiometabolic diseases
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