52 research outputs found

    A trio of month-long flares in the nova-like variable V704 And

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    We present the discovery of an unusual set of flares in the nova-like variable V704 And. Using data from AAVSO, ASAS-SN, and ZTF for the nova-like variable V704 And, we discovered a trio of brightening events that occurred during the high state. These events elevate the optical brightness of the source from ∼13.5 to ∼12.5 mag. The events last for roughly a month, and exhibit the unusual shape of a slow rise and faster decay. Immediately after the third event, we obtained data from regular monitoring with Swift, although by this time the flares had ceased and the source returned to its pre-flare level of activity in the high state. The Swift observations confirm that during the high state, the source is detectable in the X-rays, and provide simultaneous UV and optical fluxes. As the source is already in the high state prior to the flares, and therefore the disc is expected to already be in the high-viscosity state, we conclude that the driver of the variations must be changes in the mass transfer rate from the companion star and we discuss mechanisms that could lead to such short-timescale mass-transfer variations

    Typhoid toxin exhausts the RPA response to DNA replication stress driving senescence and Salmonella infection

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    Salmonella Typhi activates the host DNA damage response through the typhoid toxin, facilitating typhoid symptoms and chronic infections. Here we reveal a non-canonical DNA damage response, which we call RING (response induced by a genotoxin), characterized by accumulation of phosphorylated histone H2AX (γH2AX) at the nuclear periphery. RING is the result of persistent DNA damage mediated by toxin nuclease activity and is characterized by hyperphosphorylation of RPA, a sensor of single-stranded DNA (ssDNA) and DNA replication stress. The toxin overloads the RPA pathway with ssDNA substrate, causing RPA exhaustion and senescence. Senescence is also induced by canonical γΗ2ΑΧ foci revealing distinct mechanisms. Senescence is transmitted to non-intoxicated bystander cells by an unidentified senescence-associated secreted factor that enhances Salmonella infections. Thus, our work uncovers a mechanism by which genotoxic Salmonella exhausts the RPA response by inducing ssDNA formation, driving host cell senescence and facilitating infection

    Cost effectiveness of thrombolytic therapy with tissue plasminogen activator as compared with streptokinase for acute myocardial infarction

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    BACKGROUND. Patients with acute myocardial infarction who were treated with accelerated tissue plasminogen activator (t-PA) (given over a period of 1 1/2 hours rather than the conventional 3 hours, and with two thirds of the dose given in the first 30 minutes) had a 30-day mortality that was 15 percent lower than that of pati

    Biofuels, greenhouse gases and climate change. A review

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    Trabecular bone score in kidney transplant recipients.

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    UNLABELLED: It is uncertain whether bone mineral density (BMD) can accurately predict fracture in kidney transplant recipients. Trabecular bone score (TBS) provides information independent of BMD. Kidney transplant recipients had abnormal bone texture as measured by lumbar spine TBS, and a lower TBS was associated with incident fractures in recipients. INTRODUCTION: Trabecular bone score (TBS) is a texture measure derived from dual energy X-ray absorptiometry (DXA) lumbar spine images, providing information independent of bone mineral density. We assessed characteristics associated with TBS and fracture outcomes in kidney transplant recipients. METHODS: We included 327 kidney transplant recipients from Manitoba, Canada, who received a post-transplant DXA (median 106 days post-transplant). We matched each kidney transplant recipient (mean age 45 years, 39 % men) to three controls from the general population (matched on age, sex, and DXA date). Lumbar spine (L1-L4) DXA images were used to derive TBS. Non-traumatic incident fracture (excluding hand, foot, and craniofacial) (n = 31) was assessed during a mean follow-up of 6.6 years. We used multivariable linear regression models to test predictors of TBS, and multivariable Cox proportional hazard regression was used to estimate hazard ratios (HRs) per standard deviation decrease in TBS to express the gradient of risk. RESULTS: Compared to the general population, kidney transplant recipients had a significantly lower lumbar spine TBS (1.365 ± 0.129 versus 1.406 ± 0.125, P < 0.001). Multivariable linear regression revealed that receipt of a kidney transplant was associated with a significantly lower mean TBS compared to controls (-0.0369, 95 % confidence interval [95 % CI] -0.0537 to -0.0202). TBS was associated with fractures independent of the Fracture Risk Assessment score including BMD (adjusted HR per standard deviation decrease in TBS 1.64, 95 % CI 1.15-2.36). CONCLUSION: Kidney transplant recipients had abnormal bone texture as assessed by TBS and a lower lumbar spine TBS was associated with fractures in recipients

    Post flywheel squat vs. flywheel deadlift potentiation of lower limb isokinetic peak torques in male athletes

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    The present study investigated the post-activation performance enhancement (PAPE) of isokinetic quadriceps and hamstrings torque after flywheel (FW)-squat vs. FW-deadlift in comparison to a control condition. Fifteen male athletes were enrolled in this randomised, crossover study. Each protocol consisted of 3 sets of 6 repetitions, with an inertial load of 0.029 kg.m2. Isokinetic quadriceps (knee extension) and hamstrings (knee flexion) concentric peak torque (60\uba/s) and hamstring eccentric peak torque (-60\uba/s) were measured 5 min after experimental or control conditions. A significant condition (PAPE) effect was reported (f = 4.067, p = 0.008) for isokinetic hamstrings eccentric peak torque following FW-squat and FW-deadlift, but no significant differences were found for quadriceps and hamstrings concentric peak torques. The significant difference averaged 14 Nm between FW-squat vs. control (95% CI: 2, 28; d = 0.75, moderate; p = 0.033), and 13 Nm between FW-deadlift vs. control (95% CI: 1, 25; d = 0.68, moderate; p = 0.038). This study reported that both FW-squat and FW-deadlift exercises are equivalently capable of generating PAPE of isokinetic hamstrings eccentric torque. Practitioners may use these findings to inform strength and power development during complex training sessions consisting of flywheel-based exercises prior to a sport-specific task

    Supplementary Material for: Venous Thromboembolism and the Risk of Death and Graft Loss in Kidney Transplant Recipients

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    <p><b><i>Background:</i></b> The implications of venous thromboembolism (VTE) for morbidity and mortality in kidney transplant recipients are not well described. <b><i>Methods:</i></b> We conducted a retrospective study using linked healthcare databases in Ontario, Canada to determine the risk and complications of VTE in kidney transplant recipients from 2003 to 2013. We compared the incidence rate of VTE in recipients (<i>n</i> = 4,343) and a matched (1:4) sample of the general population (<i>n</i> = 17,372). For recipients with evidence of a VTE posttransplant, we compared adverse clinical outcomes (death, graft loss) to matched (1:2) recipients without evidence of a VTE posttransplant. <b><i>Results:</i></b> During a median follow-up of 5.2 years, 388 (8.9%) recipients developed a VTE compared to 254 (1.5%) in the matched general population (16.3 vs. 2.4 events per 1,000 person-years; hazard ratio [HR] 7.1, 95% CI 6.0-8.4; <i>p</i> < 0.0001). Recipients who experienced a posttransplant VTE had a higher risk of death (28.5 vs. 11.2%; HR 4.1, 95% CI 2.9-5.8; <i>p</i> < 0.0001) and death-censored graft loss (13.1 vs. 7.5%; HR 2.3, 95% CI 1.4-3.6; <i>p</i> = 0.0006) compared to matched recipients who did not experience a posttransplant VTE. <b><i>Conclusions:</i></b> Kidney transplant recipients have a sevenfold higher risk of VTE compared to the general population with VTE conferring an increased risk of death and graft loss.</p

    Mountain roads and non-native species modify elevational patterns of plant diversity

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    Aim: We investigated patterns of species richness and community dissimilarity along elevation gradients using globally replicated, standardized surveys of vascular plants. We asked how these patterns of diversity are influenced by anthropogenic pressures (road construction and non-native species). Location: Global. Time period: 2008-2015. Major taxa studied: Vascular plants. Methods: Native and non-native vascular plant species were recorded in 943 plots along 25 elevation gradients, in nine mountain regions, on four continents. Sampling took place in plots along and away from roads. We analysed the effects of elevation and distance from road on species richness patterns and community dissimilarity (beta-diversity), and assessed how non-native species modified such elevational diversity patterns. Results: Globally, native and total species richness showed a unimodal relationship with elevation that peaked at lower-mid elevations, but these patterns were altered along roads and due to non-native species. Differences in elevational species richness patterns between regions disappeared along roadsides, and non-native species changed the patterns' character in all study regions. Community dissimilarity was reduced along roadsides and through non-native species. We also found a significant elevational decay of beta-diversity, which however was not affected by roads or non-native species. Main conclusions: Idiosyncratic native species richness patterns in plots away from roads implicate region-specific mechanisms underlying these patterns. However, along roadsides a clearer elevational signal emerged and species richness mostly peaked at mid-elevations. We conclude that both roads and non-native species lead to a homogenization of species richness patterns and plant communities in mountains
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