Donation after Cardiac Death (DCD) is an increasingly important source of kidney transplants, but because of concerns of ischemic injury during the agonal phase, many centers abandon donation if ...cardiorespiratory arrest has not occurred within 1 h of controlled withdrawal of life‐supporting treatment (WLST). We report the impact on donor numbers and transplant function using instead a minimum ‘cut‐off’ time of 4 h. The agonal phase of 173 potential DCD donors was characterized according to the presence or absence of: acidemia; lactic acidosis; prolonged (>30 min) hypotension, hypoxia or oliguria, and the impact of these characteristics on 3‐ and 12‐month transplant outcome evaluated by multivariable regression analysis. Of the 117 referrals who became donors, 27 (23.1%) arrested more than 1 h after WLST. Longer agonal‐phase times were associated with greater donor instability, but surprisingly neither agonal‐phase instability nor its duration influenced transplant outcome. In contrast, 3‐ and 12‐month eGFR in the 190 transplanted kidneys was influenced independently by donor age, and 3‐month eGFR by cold ischemic time. DCD kidney numbers are increased by 30%, without compromising transplant outcome, by lengthening the minimum waiting time after WLST from 1 to 4 h.
Donation after cardiac death kidney numbers are increased by 30%, without compromising transplant outcome, by lengthening the minimum waiting time after withdrawal of life‐supporting treatment from 1 to 4 hours.
We made new estimates of the Galactic escape speed at various Galactocentric radii using the latest data release of the RAdial Velocity Experiment (RAVE DR4). Compared to previous studies we have a ...database that is larger by a factor of 10, as well as reliable distance estimates for almost all stars. Our analysis is based on statistical analysis of a rigorously selected sample of 90 high-velocity halo stars from RAVE and a previously published data set. We calibrated and extensively tested our method using a suite of cosmological simulations of the formation of Milky Way-sized galaxies. Our best estimate of the local Galactic escape speed, which we define as the minimum speed required to reach three virial radii R340, is 533+54-41 km s-1 (90% confidence), with an additional 4% systematic uncertainty, where R340 is the Galactocentric radius encompassing a mean overdensity of 340 times the critical density for closure in the Universe. From the escape speed we further derived estimates of the mass of the Galaxy using a simple mass model with two options for the mass profile of the dark matter halo: an unaltered and an adiabatically contracted Navarro, Frenk & White (NFW) sphere. If we fix the local circular velocity, the latter profile yields a significantly higher mass than the uncontracted halo, but if we instead use the statistics for halo concentration parameters in large cosmological simulations as a constraint, we find very similar masses for both models. Our best estimate for M340, the mass interiorto R340 (dark matter and baryons), is 1.3+0.4-0.3 × 1012 M⊙ (corresponds to M200 = 1.6+0.5-0.4 × 1012 M⊙). This estimate is in good agreement with recently published, independent mass estimates based on the kinematics of more distant halo stars and the satellite galaxy Leo I.
In the thick of it: metal-poor disc stars in RAVE Kordopatis, G.; Gilmore, G.; Wyse, R. F. G. ...
Monthly notices of the Royal Astronomical Society,
12/2013, Letnik:
436, Številka:
4
Journal Article
Recenzirano
Odprti dostop
By selecting in the Radial Velocity Experiment-fourth data release (RAVE-DR4) survey the stars located between 1 and 2 kpc above the Galactic plane, we question the consistency of the simplest ...three-component model (thin disc, thick disc and halo) for the Milky Way. We confirm that the metallicity and azimuthal velocity distribution functions of the thick disc are not Gaussian. In particular, we find that the thick disc has an extended metallicity tail going at least down to M/H = -2 dex, contributing roughly 3 per cent of the entire thick disc population and having a shorter scalelength compared to the canonical thick disc. The mean azimuthal velocity of these metal-poor stars allows us to estimate the correlation between the metallicity (M/H) and the orbital velocity (V...), which is an important constraint on the formation mechanisms of the Galactic thick disc. Given our simple approach, we find ... 50 km s... dex..., which is in very good agreement with previous literature values. We complete the study with a brief discussion on the implications of the formation scenarios for the thick disc and suggest that given the above-mentioned characteristics, a thick disc mainly formed by radial migration mechanisms seems unlikely. (ProQuest: ... denotes formulae/symbols omitted.)
We aim to characterize high-velocity (HiVel) stars in the solar vicinity both chemically and kinematically using the fourth data release of the RAdial Velocity Experiment (RAVE). We used a sample of ...57 HiVel stars with Galactic rest-frame velocities larger than 275 km s−1. With 6D position and velocity information, we integrated the orbits of the HiVel stars and found that, on average, they reach out to 13 kpc from the Galactic plane and have relatively eccentric orbits consistent with the Galactic halo. Using the stellar parameters and α/Fe estimates from RAVE, we found the metallicity distribution of the HiVel stars peak at M/H = −1.2 dex and is chemically consistent with the inner halo. There are a few notable exceptions that include a hypervelocity star candidate, an extremely HiVel bound halo star, and one star that is kinematically consistent with the halo but chemically consistent with the disc. High-resolution spectra were obtained for the metal-rich HiVel star candidate and the second highest velocity star in the sample. Using these high-resolution data, we report the discovery of a metal-rich halo star that has likely been dynamically ejected into the halo from the Galactic thick disc. This discovery could aid in explaining the assembly of the most metal-rich component of the Galactic halo.
Sulfate reducing bacteria (SRB) have existed throughout much of Earth's history and remain major contributors to carbon cycling in modern systems. Despite their importance, misconceptions about SRB ...are prevalent. In particular, SRB are commonly thought to lack oxygen tolerance and to exist only in anoxic environments. Through the last two decades, researchers have discovered that SRB can, in fact, tolerate and even respire oxygen. Investigations of microbial mat systems have demonstrated that SRB are both abundant and active in the oxic zones of mats. Additionally, SRB have been found to be highly active in the lithified zones of microbial mats, suggesting a connection between sulfate reduction and mat lithification. In the present paper, we review recent research on SRB distribution and present new preliminary findings on both the diversity and distribution of δ-proteobacterial SRB in lithifying and non-lithifying microbial mat systems. These preliminary findings indicate the unexplored diversity of SRB in a microbial mat system and demonstrate the close microspatial association of SRB and cyanobacteria in the oxic zone of the mat. Possible mechanisms and further studies to elucidate mechanisms for carbonate precipitation via sulfate reduction are also discussed.
Dramatic local population decline brought about by anthropogenic‐driven change is an increasingly common threat to biodiversity. Seabird life history traits make them particularly vulnerable to such ...change; therefore, understanding population connectivity and dispersal dynamics is vital for successful management. Our study used a 357‐base pair mitochondrial control region locus sequenced for 103 individuals and 18 nuclear microsatellite loci genotyped for 245 individuals to investigate population structure in the Atlantic and Pacific populations of the pelagic seabird, Leach’s storm‐petrel Oceanodroma leucorhoa leucorhoa. This species is under intense predation pressure at one regionally important colony on St Kilda, Scotland, where a disparity between population decline and predation rates hints at immigration from other large colonies. amova, FST,ΦST and Bayesian cluster analyses revealed no genetic structure among Atlantic colonies (Global ΦST = −0.02 P > 0.05, Global FST = 0.003, P > 0.05, structureK = 1), consistent with either contemporary gene flow or strong historical association within the ocean basin. The Pacific and Atlantic populations are genetically distinct (Global ΦST = 0.32 P < 0.0001, Global FST = 0.04, P < 0.0001, structureK = 2), but evidence for interocean exchange was found with individual exclusion/assignment and population coalescent analyses. These findings highlight the importance of conserving multiple colonies at a number of different sites and suggest that management of this seabird may be best viewed at an oceanic scale. Moreover, our study provides an illustration of how long‐distance movement may ameliorate the potentially deleterious impacts of localized environmental change, although direct measures of dispersal are still required to better understand this process.
Long-term effects of aluminium dust inhalation Peters, Susan; Reid, Alison; Fritschi, Lin ...
Occupational and environmental medicine (London, England),
12/2013, Letnik:
70, Številka:
12
Journal Article
Recenzirano
Objectives During the 1950s and 1960s, aluminium dust inhalation was used as a potential prophylaxis against silicosis in underground miners, including in Australia. We investigated the association ...between aluminium dust inhalation and cardiovascular, cerebrovascular and Alzheimer's diseases in a cohort of Australian male underground gold miners. We additionally looked at pneumoconiosis mortality to estimate the effect of the aluminium therapy. Methods SMRs and 95% CI were calculated to compare mortality of the cohort members with that of the Western Australian male population (1961–2009). Internal comparisons on duration of aluminium dust inhalation were examined using Cox regression. Results Aluminium dust inhalation was reported for 647 out of 1894 underground gold miners. During 42 780 person-years of follow-up, 1577 deaths were observed. An indication of increased mortality of Alzheimer's disease among miners ever exposed to aluminium dust was found (SMR=1.38), although it was not statistically significant (95% CI 0.69 to 2.75). Rates for cardiovascular and cerebrovascular death were above population levels, but were similar for subjects with or without a history of aluminium dust inhalation. HRs suggested an increasing risk of cardiovascular disease with duration of aluminium dust inhalation (HR=1.02, 95% CI 1.00 to 1.04, per year of exposure). No difference in the association between duration of work underground and pneumoconiosis was observed between the groups with or without aluminium dust exposure. Conclusions No protective effect against silicosis was observed from aluminium dust inhalation. Conversely, exposure to aluminium dust may possibly increase the risk of cardiovascular disease and dementia of the Alzheimer's type.
ABSTRACT
A ‘proof of principle’ is presented, whereby the Ohmic and viscous heating determined by a three-dimensional (3D) MHD model of a coronal avalanche are used as the coronal heating input for a ...series of field-aligned, one-dimensional (1D) hydrodynamic models. Three-dimensional coronal MHD models require large computational resources. For current numerical parameters, it is difficult to model both the magnetic field evolution and the energy transport along field lines for coronal temperatures much hotter than $1\, \mathrm{MK}$, because of severe constraints on the time step from parallel thermal conduction. Using the 3D MHD heating derived from a simulation and evaluated on a single field line, the 1D models give coronal temperatures of $1\, \mathrm{MK}$ and densities $10^{14}\textrm {--}10^{15}\, \mathrm{m}^{-3}$ for a coronal loop length of $80\, \mathrm{Mm}$. While the temperatures and densities vary smoothly along the field lines, the heating function leads to strong asymmetries in the plasma flows. The magnitudes of the velocities in the 1D model are comparable with those seen in 3D reconnection jets in our earlier work. Advantages and drawbacks of this approach for coronal modelling are discussed.
Asbestos-related diseases Musk, A. W.; de Klerk, N.; Reid, A. ...
The international journal of tuberculosis and lung disease,
06/2020, Letnik:
24, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Knowledge of asbestos-related diseases has been accumulating for over one hundred years as the industrial value of asbestos was recognised for the strength of its fibres and their resistance to ...destruction, resulting in increasing production and use until the multiple health effects
have become apparent. Deposition in the lung parenchyma results in an inflammatory/progressively fibrotic response, with impaired gas exchange and reduced lung compliance ('asbestosis'), causing progressive dyspnoea and respiratory failure for which only palliation is indicated, although
anti-fibrotic agents used for idiopathic usual interstitial pneumonitis remain to be evaluated. Benign pleural effusion, diffuse pleural fibrosis (occasionally with associated rolled atelectasis) and pleural plaques are the non-malignant pleural diseases that result from fibres reaching the
pleura. But the main issues that led to the ban on asbestos in industry are those of malignancy: lung cancer, malignant mesothelioma (MM) of the pleura and MM of the peritoneum. Bronchogenic carcinoma risk from asbestos exposure is dose-dependent and multiplies the risk attributable to tobacco
smoking. The principles of treatment are as for all cases of lung cancer. Low-dose computed tomography screening of exposed people can detect early-stage, non-small cell cancers, with improved survival. The amphibole varieties of asbestos are much more potent causes of MM than chrysotile,
and the risk increases exponentially for 40-50 years following first exposure. As MM is non-resectable and poorly responsive to chemotherapy and radiotherapy, curative treatment is not possible and screening not justified.
Malignant mesothelioma (MM) of the pleura or peritoneum is a universally fatal disease attracting an increasing range of medical interventions and escalating healthcare costs. Changes in survival and ...the factors affecting survival of all patients ever diagnosed with MM in Western Australia over the past five decades and confirmed by the Western Australian Mesothelioma Registry to December 2005 were examined. Sex, age, date and method of diagnosis, site of disease and histological type were recorded. Date of onset of symptoms and performance status were obtained from clinical notes for a sample of cases. Cox regression was used to examine the association of the clinical variables and the 10-yr periods of disease onset with survival after diagnosis. Survival was inversely related to age, being worse for males (hazard ratio (HR) 1.4, 95% CI 1.2-1.6), and those with peritoneal mesothelioma (HR 1.4, 95% CI 1.1-1.7). Patients with sarcomatoid histology had worse prognosis than patients with epithelioid and biphasic histological subtypes. Survival improved after the 1970s and has made incremental improvements since then. Median (interquartile range) survival by decade, from 1960 until 2005, was 64 (0-198), 177 (48-350), 221 (97-504), 238 (108-502) and 301 (134-611) days; ~4 weeks of this apparent improvement can be attributed to earlier diagnosis. With increasing resources and treatment costs for MM over the past 40 yrs, there have been modest improvements in survival but no complete remissions.
PDF
