500 research outputs found
Gemini NIFS survey of feeding and feedback processes in nearby Active Galaxies: I - Stellar kinematics
We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the
stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby
Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral
resolution of 40 km/s. We find that the line-of-sight (LOS) velocity fields for
most galaxies are well reproduced by rotating disk models. The kinematic
position angle (PA) derived for the LOS velocity field is consistent with the
large scale photometric PA. The residual velocities are correlated with the
hard X-ray luminosity, suggesting that more luminous AGN have a larger impact
in the surrounding stellar dynamics. The central velocity dispersion values are
usually higher than the rotation velocity amplitude, what we attribute to the
strong contribution of bulge kinematics in these inner regions. For 50% of the
galaxies, we find an inverse correlation between the velocities and the
Gauss-Hermitte moment, implying red wings in the blueshifted side and blue
wings in the redshifted side of the velocity field, attributed to the movement
of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and
Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational
potential of a nuclear bar. Velocity dispersion maps show rings of low-
values (50-80 km/s) for 4 objects and "patches" of low-sigma for 6 galaxies at
150-250 pc from the nucleus, attributed to young/ intermediate age stellar
populations.Comment: To be published in MNRA
Gemini NIFS survey of feeding and feedback in nearbyActive Galaxies - III. Ionized versus warm molecular gasmasses and distributions
We have used the Gemini Near-Infrared Integral Field Spectrograph (NIFS) in
the J and K bands to map the distribution, excitation and kinematics of the
ionized HII and warm molecular gas H, in the inner few 100 pc of 6 nearby
active galaxies: NGC 788, Mrk 607, NGC 3227, NGC 3516, NGC 5506, NGC 5899. {For
most galaxies, this is the first time that such maps have been obtained}. The
ionized and H gas show distinct kinematics: while the H gas is mostly
rotating in the galaxy plane with low velocity dispersion (), the
ionized gas usually shows signatures of outflows associated with higher
values, most clearly seen in the [FeII] emission line. These two gas
species also present distinct flux distributions: the H is more uniformly
spread over the whole galaxy plane, while the ionized gas is more concentrated
around the nucleus and/or collimated along the ionization axis of its Active
Galactic Nucleus (AGN), presenting a steeper gradient in the average surface
mass density profile than the H gas. The total HII masses cover the range
M, with surface mass densities in the range
3-150 M pc, while for the warm H the values are 10
times lower. We estimate that the available gas reservoir is at least
100 times more massive than needed to power the AGN. If this gas form new stars
the star-formation rates, obtained from the Kennicutt-schmidt scalling
relation, are in the range 1-260 10 M yr. But
the gas will also - at least in part - be ejected in the form of the observed
otflows
Clinical correlates of renal dysfunction in hypertensive patients without cardiovascular complications: the REDHY study
Our study was aimed to assess the clinical correlates of different degrees of renal dysfunction in a wide group of non-diabetic hypertensive patients, free from cardiovascular (CV) complications and known renal diseases, participating to the REDHY (REnal Dysfunction in HYpertension) study. A total of 1856 hypertensive subjects (mean age: 47±14 years), attending our hypertension centre, were evaluated. The glomerular filtration rate (GFR) was estimated by the simplified Modification of Diet in Renal Disease Study prediction equation. A 24-h urine sample was collected to determine albumin excretion rate (AER). Albuminuria was defined as an AER greater than 20 μg min−1. We used the classification proposed by the US National Kidney Foundation's guidelines for chronic kidney disease (CKD) to define the stages of renal function impairment. In multiple logistic regression analysis, the probability of having stage 1 and stage 2 CKD was significantly higher in subjects with greater values of systolic blood pressure (SBP) and with larger waist circumference. SBP was also positively related to stage 3 CKD. Stage 3 and stages 4–5 CKD were inversely associated with waist circumference and directly associated with serum uric acid. Age was inversely related to stage 1 CKD and directly related to stage 3 CKD. The factors associated with milder forms of kidney dysfunction are, in part, different from those associated with more advanced stages of renal function impairment
Association of Mild to Moderate Chronic Kidney Disease With Venous Thromboembolism Pooled Analysis of Five Prospective General Population Cohorts
BACKGROUND: Recent findings suggest that chronic kidney disease (CKD) may be associated with increased risk of venous thromboembolism (VTE). Given the high prevalence of mild-to-moderate CKD in the general population, in depth analysis of this association is warranted. METHODS AND RESULTS: We pooled individual participant data from five community-based cohorts from Europe (HUNT2, PREVEND and Tromsø study) and United States (ARIC and CHS study) to assess the association of estimated glomerular filtration rate (eGFR), albuminuria and CKD with objectively verified VTE. To estimate adjusted hazard ratios (HRs) for VTE, categorical and continuous spline models were fit using Cox regression with shared-frailty or random-effect meta-analysis. A total of 1,178 VTE events occurred over 599,453 person-years follow-up. Relative to eGFR 100 mL/min/1.73m(2), HRs for VTE were 1.29 (95%CI, 1.04-1.59) for eGFR 75, 1.31 (1.00-1.71) for 60, 1.82 (1.27-2.60) for 45 and 1.95 (1.26-3.01) for 30 mL/min/1.73m(2). Compared with albumin-creatinine ratio (ACR) of 5.0 mg/g, the HRs for VTE were 1.34 (1.04-1.72) for 30 mg/g, 1.60 (1.08-2.36) for 300 mg/g and 1.92 (1.19-3.09) for 1000 mg/g. There was no interaction between clinical categories of eGFR and ACR (P=0.20). The adjusted HR for CKD defined as eGFR <60 mL/min/1.73m(2) or albuminuria ≥30 mg/g (vs. no CKD) was 1.54 (95%CI, 1.15-2.06). Associations were consistent in subgroups according to age, gender, and comorbidities as well as for unprovoked versus provoked VTE. CONCLUSIONS: Both eGFR and ACR are independently associated with increased risk of VTE in the general population, even across the normal eGFR and ACR ranges
Long-term exposure to ambient particulate matter and prevalence of subclinical atherosclerosis in the Multiethnic Study of Atherosclerosis (MESA)
http://deepblue.lib.umich.edu/bitstream/2027.42/57884/1/Long Term Exposure to Ambient Particulate Matter and Prevalance of Subclinical Athersclerosis in the Multiethnic Study of Atherosclerosis .pd
“Contextual” Synthetic Lethality and/or Loss of Heterozygosity: Tumor Hypoxia and Modification of DNA Repair
Association of APOE polymorphism with chronic kidney disease in a nationally representative sample: a Third National Health and Nutrition Examination Survey (NHANES III) Genetic Study
<p>Abstract</p> <p>Background</p> <p>Apolipoprotein E polymorphisms (<it>APOE</it>) have been associated with lowered glomerular filtration rate (GFR) and chronic kidney disease (CKD) with e2 allele conferring risk and e4 providing protection. However, few data are available in non-European ethnic groups or in a population-based cohort.</p> <p>Methods</p> <p>The authors analyzed 5,583 individuals from the Third National Health and Nutrition Examination Survey (NHANES III) to determine association with estimated GFR by the Modification of Diet in Renal Disease (MDRD) equation and low-GFR cases. Low-GFR cases were defined as GFR <75 ml/min/1.73 m<sup>2</sup>; additionally, GFR was analyzed continuously.</p> <p>Results</p> <p>In univariate analysis, the e4 allele was negatively associated with low-GFR cases in non-Hispanic whites, odds ratio (OR): 0.76, 95% confidence interval (CI): 0.60, 0.97. In whites, there was a significant association between increasing <it>APOE </it>score (indicating greater number of e2 alleles) and higher prevalence of low-GFR cases (OR: 1.21, 95%CI: 1.01, 1.45). Analysis of continuous GFR in whites found the e4 allele was associated with higher levels of continuous GFR (β-coefficient: 2.57 ml/min/1.73 m<sup>2</sup>, 95%CI: 0.005, 5.14); in non-Hispanic blacks the e2 allele was associated with lower levels of continuous GFR (β-coefficient: -3.73 ml/min/1.73 m<sup>2</sup>, 95%CI: -6.61, -0.84). <it>APOE </it>e2 and e4 alleles were rare and not associated with low-GFR cases or continuous GFR in Mexican Americans.</p> <p>Conclusion</p> <p>In conclusion, the authors observed a weak association between the <it>APOE </it>e4 allele and low-GFR cases and continuous GFR in non-Hispanic whites, and the <it>APOE </it>e2 allele and continuous GFR in non-Hispanic blacks, but found no association with either measure of kidney function in Mexican Americans. Larger studies including multiethnic groups are needed to determine the significance of this association.</p
Functional intercomparison of intraoperative radiotherapy equipment – Photon Radiosurgery System
BACKGROUND: Intraoperative Radiotherapy (IORT) is a method by which a critical radiation dose is delivered to the tumour bed immediately after surgical excision. It is being investigated whether a single high dose of radiation will impart the same clinical benefit as a standard course of external beam therapy. Our centre has four Photon Radiosurgery Systems (PRS) currently used to irradiate breast and neurological sites. MATERIALS AND METHODS: The PRS comprises an x-ray generator, control console, quality assurance tools and a mobile gantry. We investigated the dosimetric characteristics of each source and its performance stability over a period of time. We investigated half value layer, output diminution factor, internal radiation monitor (IRM) reproducibility and depth-doses in water. The half value layer was determined in air by the broad beam method, using high purity aluminium attenuators. To quantify beam hardening at clinical depths, solid water attenuators of 5 and 10 mm were placed between the x-ray probe and attenuators. The ion chamber current was monitored over 30 minutes to deduce an output diminution factor. IRM reproducibility was investigated under various exposures. Depth-dose curves in water were obtained at distances up to 35 mm from the probe. RESULTS: The mean energies for the beam attenuated by 5 and 10 mm of solid water were derived from ICRU Report 17 and found to be 18 and 24 keV. The average output level over a period of 30 minutes was found to be 99.12%. The average difference between the preset IRM limit and the total IRM count was less than 0.5%. For three x-ray sources, the average difference between the calculated and actual treatment times was found to be 0.62% (n = 30). The beam attenuation in water varied by approximately 1/r(3). CONCLUSION: The x-ray sources are stable over time. Most measurements were found to lie within the manufacturer's tolerances and an intercomparison of these checks suggests that the four x-ray sources have similar performance characteristics
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