84 research outputs found

    Association Between Urinary Markers of Nucleic Acid Oxidation and Mortality in Type 2 Diabetes:A population-based cohort study

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    OBJECTIVE: We recently showed that RNA oxidation, estimated by urinary excretion of 8-oxo-7,8-dihydroguanosine (8-oxoGuo), independently predicted mortality in a cohort of 1,381 treatment-naive patients with newly diagnosed type 2 diabetes. In the present investigation, we analyzed urine collected 6 years after the diagnosis to assess the association between urinary markers of nucleic acid oxidation and mortality in patients with established and treated diabetes. RESEARCH DESIGN AND METHODS: We used data from the 970 patients who attended the screening for diabetes complications 6 years after the diagnosis. Cox proportional hazards regression was used to examine the relationship between urinary markers of DNA oxidation (8-oxo-7,8-dihydro-2′-deoxyguanosine [8-oxodG] [n = 938]) and RNA oxidation (8-oxoGuo [n = 936]) and mortality. RESULTS: During a median of 9.8 years of follow-up, 654 patients died. Urinary 8-oxoGuo assessed 6 years after the diagnosis was significantly associated with mortality. The multivariate-adjusted hazard ratios for all-cause and diabetes-related mortality of patients with 8-oxoGuo levels in the highest quartile compared with those in the lowest quartile were 1.86 (95% CI 1.34–2.58) and 1.72 (1.11–2.66), respectively. Conversely, 8-oxodG was not associated with mortality. In addition, we found an association between changes in 8-oxoGuo from diagnosis to 6-year follow-up and mortality, with increased risk in patients with an increase and decreased risk in patients with a decrease in 8-oxoGuo. CONCLUSIONS: The RNA oxidation marker 8-oxoGuo is an independent predictor of mortality in patients with established and treated type 2 diabetes, and changes in 8-oxoGuo during the first 6 years after diagnosis are associated with mortality

    Non--power law behavior of the radial profile of phase--space density of halos

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    We study the pseudo phase-space density, ρ(r)/σ3(r)\rho(r)/\sigma^3(r), of Λ\LambdaCDM dark matter halos with and without baryons (baryons+DM, and pure DM), by using the model introduced in Del Popolo (2009), which takes into account the effect of dynamical friction, ordered and random angular momentum, baryons adiabatic contraction and dark matter baryons interplay. We examine the radial dependence of ρ(r)/σ3(r)\rho(r)/\sigma^3(r) over 9 orders of magnitude in radius for structures on galactic and cluster of galaxies scales. We find that ρ(r)/σ3(r)\rho(r)/\sigma^3(r) is approximately a power-law only in the range of halo radius resolved by current simulations (down to 0.1% of the virial radius) while it has a non-power law behavior below the quoted scale, with inner profiles changing with mass. The non-power-law behavior is more evident for halos constituted both of dark matter and baryons while halos constituted just of dark matter and with angular momentum chosen to reproduce a Navarro-Frenk-White (NFW) density profile, are characterized by an approximately power-law behavior. The results of the present paper lead to conclude that density profiles of the NFW type are compatible with a power-law behavior of ρ(r)/σ3(r)\rho(r)/\sigma^3(r), while those flattening to the halo center, like those found in Del Popolo (2009) or the Einasto profile, or the Burkert profile, cannot produce radial profile of the pseudo-phase-space density that are power-laws at all radii. The results argue against universality of the pseudo phase-space density and as a consequence argue against universality of density profiles constituted by dark matter and baryons as also discussed in Del Popolo (2009).Comment: 20 pages; 7 figs. arXiv admin note: substantial text overlap with arXiv:0906.4447 and arXiv:1012.432

    Population genomics of post-glacial western Eurasia.

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    Western Eurasia witnessed several large-scale human migrations during the Holocene <sup>1-5</sup> . Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes-mainly from the Mesolithic and Neolithic periods-from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a 'great divide' genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 BP, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 BP, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a 'Neolithic steppe' cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations

    Publisher Correction: Population genomics of post-glacial western Eurasia.

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    Physical Processes in Star Formation

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    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio
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