ABSTRACT
Tidal disruption events (TDEs) are characterized by the emission of a short burst of high-energy radiation. We analyse the cumulative impact of TDEs on galactic habitability using the Milky ...Way as a proxy. We show that X-rays and extreme ultraviolet radiation emitted during TDEs can cause hydrodynamic escape and instigate biological damage. By taking the appropriate variables into consideration, such as the efficiency of atmospheric escape and distance from the Galactic centre, we demonstrate that the impact of TDEs on galactic habitability is comparable to that of active galactic nuclei. In particular, we show that planets within distances of ∼0.1–1 kpc could lose Earth-like atmospheres over the age of the Earth, and that some of them might be subject to biological damage once every ≳ 104 yr. We conclude by highlighting potential ramifications of TDEs and argue that they should be factored into future analyses of inner galactic habitability.
ABSTRACT
It is well known that active galactic nuclei (AGNs) are accompanied by winds and outflows, some of which may reach weakly relativistic speeds of about 10 per cent the speed of light. Yet, in ...spite of their ubiquity, the impact of AGN outflows in modulating surface habitability of terrestrial planets on galactic scales, using the Milky Way as the basis for comparison, is poorly investigated and inadequately understood. In this work, we address this issue by focusing on two key mechanisms: AGN winds can heat atmospheres and drive the atmospheric escape, as well as stimulate the formation of nitrogen oxides and thence cause ozone depletion. By developing simple models, we estimate the maximal distance up to which these deleterious effects are rendered significant for Earth-like planets in the Milky Way, and thereby demonstrate that this value may extend to ≲ 1 kpc. In the case of quasars hosting larger supermassive black holes, such effects could actually influence the AGN host galaxy as a whole.
We discuss spherical needlets and their properties. Needlets are a form of spherical wavelets which do not rely on any kind of tangent plane approximation and enjoy good localization properties in ...both pixel and harmonic space; moreover needlet coefficients are asymptotically uncorrelated at any fixed angular distance, which makes their use in statistical procedures very promising. In view of these properties, we believe needlets may turn out to be especially useful in the analysis of cosmic microwave background (CMB) data on the incomplete sky, as well as of other cosmological observations. As a final advantage, we stress that the implementation of needlets is computationally very convenient and may rely completely on standard data analysis packages such as healpix.
There is no consensus in the literature on the best renal replacement therapy (RRT) in acute kidney injury (AKI), with both hemodialysis (HD) and peritoneal dialysis (PD) being used as AKI therapy. ...However, there are concerns about the inadequacy of PD as well as about the intermittency of HD complicated by hemodynamic instability. Recently, continuous replacement renal therapy (CRRT) have become the most commonly used dialysis method for AKI around the world. A prospective randomized controlled trial was performed to compare the effect of high volume peritoneal dialysis (HVPD) with daily hemodialysis (DHD) on AKI patient survival. A total of 120 patients with acute tubular necrosis (ATN) were assigned to HVPD or DHD in a tertiary-care university hospital. The primary end points were hospital survival rate and renal function recovery, with metabolic control as the secondary end point. Sixty patients were treated with HVPD and 60 with DHD. The HVPD and DHD groups were similar for age (64.2±19.8 and 62.5±21.2 years), gender (male: 72 and 66%), sepsis (42 and 47%), hemodynamic instability (61 and 63%), severity of AKI (Acute Tubular Necrosis-Index Specific Score (ATN-ISS): 0.68±0.2 and 0.66±0.2), Acute Physiology, Age, and Chronic Health Evaluation Score (APACHE II) (26.9±8.9 and 24.1±8.2), pre-dialysis BUN (116.4±33.6 and 112.6±36.8 mg per 100 ml), and creatinine (5.8±1.9 and 5.9±1.4 mg per 100 ml). Weekly delivered Kt/V was 3.6±0.6 in HVPD and 4.7±0.6 in DHD (P<0.01). Metabolic control, mortality rate (58 and 53%), and renal function recovery (28 and 26%) were similar in both groups, whereas HVPD was associated with a significantly shorter time to the recovery of renal function. In conclusion, HVPD and DHD can be considered as alternative forms of RRT in AKI.
Several statistical anomalies in the cosmic microwave background (CMB) temperature anisotropies seem to defy the assumption of a homogeneous and isotropic universe. In particular, a dipole modulation ...has been detected both in WMAP and Planck data. We adapt the methodology proposed by Eriksen et al. on CMB data to galaxy surveys, tracing the large-scale structure. We analyse the National Radio Astronomy Observatory (NRAO) and Very Large Array (VLA) Sky Survey data at a resolution of ∼2° for three different flux thresholds: 2.5, 5.0 and 10.0 mJy, respectively. No evidence of a dipole modulation is found. This result suggests that the origin of the dipole asymmetry found in the CMB cannot be assigned to secondary anisotropies produced at redshifts around z = 1. However, it could still have been generated at redshifts higher or lower, such as the integrated Sachs–Wolfe effect produced by the local structures. Other all-sky surveys, like the infrared WISE catalogue, could help to explore with a high sensitivity a redshift interval closer than the one probed with NVSS.
BACKGROUND AND PURPOSE Strategies designed to enhance cerebral cAMP have been proposed as symptomatic treatments to counteract cognitive deficits. However, pharmacological therapies aimed at reducing ...PDE4, the main class of cAMP catabolizing enzymes in the brain, produce severe emetic side effects. We have recently synthesized a 3‐cyclopentyloxy‐4‐methoxybenzaldehyde derivative, structurally related to rolipram, and endowed with selective PDE4D inhibitory activity. The aim of the present study was to investigate the effect of the new drug, namely GEBR‐7b, on memory performance, nausea, hippocampal cAMP and amyloid‐β (Aβ) levels.
EXPERIMENTAL APPROACH To measure memory performance, we performed object recognition tests on rats and mice treated with GEBR‐7b or rolipram. The emetic potential of the drug, again compared with rolipram, was evaluated in rats using the taste reactivity test and in mice using the xylazine/ketamine anaesthesia test. Extracellular hippocampal cAMP was evaluated by intracerebral microdialysis in freely moving rats. Levels of soluble Aβ peptides were measured in hippocampal tissues and cultured N2a cells by elisa.
KEY RESULTS GEBR‐7b increased hippocampal cAMP, did not influence Aβ levels and improved spatial, as well as object memory performance in the object recognition tests. The effect of GEBR‐7b on memory was 3 to 10 times more potent than that of rolipram, and its effective doses had no effect on surrogate measures of emesis in rodents.
CONCLUSION AND IMPLICATIONS Our results demonstrate that GEBR‐7b enhances memory functions at doses that do not cause emesis‐like behaviour in rodents, thus offering a promising pharmacological perspective for the treatment of memory impairment.
Introduction Conduction studies (ENMG) have been used since long time for evaluation of chronic uremia ( O’Regan et al., 2012 ) and the blink reflex is important for this purpose. Neurological ...alterations are easy to detect in uremic patients ( Vellanki and Bansal, 2015 ), such as deep hyperreflexia, asterixis, reading and memory disturbances and sleep disorders ( Merlino et al., 2008 ). They can occur together or alone in early stages of chronic uremia, but they have not been quantified to this moment, the purpose of this study. Methods Peripheral neuropathy was diagnosed by ENMG and classified into four levels: Normal – 0.0 point; mild – 1,0 point; moderate – 2,0 points; marked – 3,0 points. The blink reflex was classified into Normal – 0.0 point; R1 alterations – 1,0 point; one side R2 alteration – 2,0 points; both sides R2 alterations – 3,0 points. Maximal electrophysiological assessment: 6,0 points. Clinical alterations were defined as having or not asterixis (0.0 or 1,0 point, respectively), having or not deep hyperreflexia (0.0 or 1,0 point); having or not reading and/or memory disorders (0.0 or 1.0), having or not sleep disorders (0.0 or 1.0). Clinical evaluation: maximum of 4,0 points. The full scale ranges from zero to ten (10) points in ascending graduation related to the severity ( Table 1 ). Results In previous studies of 30 patients in our Service were documented several alterations of the blink reflex, some of them with prognostic value. Attenuated R2 responses occurred in patients who died soon after the study. The application of the proposed scale for the first 10 patients showed results between 1 to 7 points. Values of 1 to 3 were observed in patients with shorter time of dialysis treatment and 6 or 7 values in patients with longer time of dialysis. Conclusions This study propose a new scale of assessment of the central and peripheric nervous system impairment in chronic uremia. The procedures are non-invasive, fast, easy to apply and already showed to be useful. They can be applied by nephrologists and neurologists, to teaching and research in interdisciplinarity Neurology/Nephrology.
This study presents a comprehensive view of the histological and functional status of the prostate of adult rat offspring of mothers subjected to gestational diabetes induced by alloxan. The ventral ...prostate of male adult offspring of diabetic (DP) or normal (CP) mothers was evaluated for collagen fibres, cell death, fibroblasts, smooth muscle cells, cell proliferation, matrix metalloproteinases (MMPs), androgen receptors (AR), transforming growth factor β1 (TGFβ-1), catalase and total antioxidant activity. The prostates of DP animals were lower in weight than those of the CP group. The DP group also exhibited hyperglycaemia and hypotestosteronemia, higher cell proliferation and AR expression, a reduction in α-actin (possibly interfering with the reproductive function of the prostate), and enhanced activity of MMP-2, although the absolute content of MMP-2 was lower in this group. These findings were associated with increased TGFβ-1 and decreased collagen distribution. The prostates of DP rats additionally exhibited reductions in catalase and total antioxidant activity. Thus, rats developing in a diabetic intrauterine environment have glycaemic and hormonal changes that impact on the structure and physiology of the prostate in adulthood. The increased AR expression possibly leads to elevated cell proliferation. Stromal remodelling was characterized by enhanced activity of MMP-2 and collagen degradation, even with increased TGFβ-1 activation. These changes associated with increased oxidative stress might interfere with tissue architecture and glandular homeostasis.
Complete absence of thyroid hormone is incompatible with life in vertebrates. Thyroxine is synthesized within thyroid follicles upon iodination of thyroglobulin conveyed from the endoplasmic ...reticulum (ER), via the Golgi complex, to the extracellular follicular lumen. In congenital hypothyroidism from biallelic thyroglobulin mutation, thyroglobulin is misfolded and cannot advance from the ER, eliminating its secretion and triggering ER stress. Nevertheless, untreated patients somehow continue to synthesize sufficient thyroxine to yield measurable serum levels that sustain life. Here, we demonstrate that TGW2346R/W2346R humans, TGcog/cog mice, and TGrdw/rdw rats exhibited no detectable ER export of thyroglobulin, accompanied by severe thyroidal ER stress and thyroid cell death. Nevertheless, thyroxine was synthesized, and brief treatment of TGrdw/rdw rats with antithyroid drug was lethal to the animals. When untreated, remarkably, thyroxine was synthesized on the mutant thyroglobulin protein, delivered via dead thyrocytes that decompose within the follicle lumen, where they were iodinated and cannibalized by surrounding live thyrocytes. As the animals continued to grow goiters, circulating thyroxine increased. However, when TGrdw/rdw rats age, they cannot sustain goiter growth that provided the dying cells needed for ongoing thyroxine synthesis, resulting in profound hypothyroidism. These results establish a disease mechanism wherein dead thyrocytes support organismal survival.
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