767 research outputs found

    Differential cost analysis with simultaneous potentials and anti-potentials

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    We present a novel approach to differential cost analysis that, given a program revision, attempts to statically bound the difference in resource usage, or cost, between the two program versions. Differential cost analysis is particularly interesting because of the many compelling applications for it, such as detecting resource-use regressions at code-review time or proving the absence of certain side-channel vulnerabilities. One prior approach to differential cost analysis is to apply relational reasoning that conceptually constructs a product program on which one can over-approximate the difference in costs between the two program versions. However, a significant challenge in any relational approach is effectively aligning the program versions to get precise results. In this paper, our key insight is that we can avoid the need for and the limitations of program alignment if, instead, we bound the difference of two cost-bound summaries rather than directly bounding the concrete cost difference. In particular, our method computes a threshold value for the maximal difference in cost between two program versions simultaneously using two kinds of cost-bound summaries---a potential function that evaluates to an upper bound for the cost incurred in the first program and an anti-potential function that evaluates to a lower bound for the cost incurred in the second. Our method has a number of desirable properties: it can be fully automated, it allows optimizing the threshold value on relative cost, it is suitable for programs that are not syntactically similar, and it supports non-determinism. We have evaluated an implementation of our approach on a number of program pairs collected from the literature, and we find that our method computes tight threshold values on relative cost in most example

    Giovani nefrologi che fanno ricerca: quando scienza e passione si incontrano

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    La ricerca scientifica rappresenta il futuro della nefrologia e la ricerca del domani appartiene ai nefrologi del domani. I giovani nefrologi possono avere diverse opportunità per coltivare la ricerca. Le buone idee e l'esperienza accumulata, tuttavia, non sono le sole chiavi per il successo. La scienza deve sempre incontrare la passione e la curiosità. Presentiamo qui la storia di un giovane nefrologo con le sue esperienze personali di ricerca, dai primi passi ai primi traguardi, come modo per dimostrare agli altri giovani colleghi che l'entusiasmo scientifico e la devozione alla scienza spesso rendono i sogni realizzabili

    Renal Concerns in the Treatment of Chronic Hepatitis B with Tenofovir

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    Tenofovir, a third generation oral nucleos(t)ide analogue, currently represents one of the first-line drugs recommended for treating chronic hepatitis B virus (HBV) infection. After oral administration, tenofovir is mostly excreted in the urine by glomerular filtration and proximal tubular secretion. Hence, an impaired kidney function may lead to an increased renal exposure to the drug in patients with coexistent renal damage. This could further worsen kidney disease through different mechanisms of nephrotoxicity such as mitochondrial DNA depletion and tubular cytotoxicity. Despite several studies performed so far to assess tenofovir-related renal toxicity, data in HBV patients are not yet conclusive. Screening of risk factors for kidney disease before starting therapy and a careful monitoring of serum creatinine, glomerular filtration rate, serum phosphate and urine analysis during treatment are advocated to adjust the dose or stop treatment if needed. New biomarkers of tubular injury, such as neutrophil gelatinase associated lipocalin, could become helpful in the future for the timely identification and risk stratification of renal damage induced by tenofovir

    Effects of Vitamin E-Coated versus Conventional Membranes in Chronic Hemodialysis Patients: A Systematic Review and Meta-Analysis

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    Introduction: Accruing evidence suggests that vitamin E-coated membranes (ViE-m) might improve the clinical management of chronic hemodialysis (HD) patients. Methods: We conducted a systematic review and meta-analysis of RCTs comparing ViE-m to conventional HD. Endpoints of interest were a series of biomarkers pertaining to anemia status, inflammation, oxidative stress and dialysis efficacy/status. Results: Sixty studies were included. ViE-m significantly improved the Erythropoietin Resistance Index but had no impact on other anemia parameters. As for oxidative stress and inflammation, ViE-m produced a significant decrease in interleukin-6 levels, thiobarbituric acid reactive substances, plasma and red blood cell (RBC) malonylaldehyde and a significant increase in blood and RBC vitamin E. Conversely, ViE-m use had no impact on lipid profile, dialysis adequacy, blood pressure, albumin and uric acid. Conclusions: ViE-m might ameliorate anemia management by reducing oxidative stress and inflammation. Benefits of these bio-membranes on harder clinical outcomes are uncertain and need to be investigated by future, targeted trials

    Differential cost analysis with simultaneous potentials and anti-potentials

    Get PDF
    We present a novel approach to differential cost analysis that, given a program revision, attempts to statically bound the difference in resource usage, or cost, between the two program versions. Differential cost analysis is particularly interesting because of the many compelling applications for it, such as detecting resource-use regressions at code-review time or proving the absence of certain side-channel vulnerabilities. One prior approach to differential cost analysis is to apply relational reasoning that conceptually constructs a product program on which one can over-approximate the difference in costs between the two program versions. However, a significant challenge in any relational approach is effectively aligning the program versions to get precise results. In this paper, our key insight is that we can avoid the need for and the limitations of program alignment if, instead, we bound the difference of two cost-bound summaries rather than directly bounding the concrete cost difference. In particular, our method computes a threshold value for the maximal difference in cost between two program versions simultaneously using two kinds of cost-bound summaries---a potential function that evaluates to an upper bound for the cost incurred in the first program and an anti-potential function that evaluates to a lower bound for the cost incurred in the second. Our method has a number of desirable properties: it can be fully automated, it allows optimizing the threshold value on relative cost, it is suitable for programs that are not syntactically similar, and it supports non-determinism. We have evaluated an implementation of our approach on a number of program pairs collected from the literature, and we find that our method computes tight threshold values on relative cost in most examples

    Alterations of lipid metabolism in chronic nephropathies: mechanisms, diagnosis and treatment.

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    Nephropathic subjects show an increased tendency to develop cardiovascular diseases, mainly as the consequence of several risk factors including increased oxidative stress, inflammation, physical inactivity, anemia, vascular calcification, and endothelial dysfunction. The alterations in lipid metabolism represent a relatively lesser important cause of genesis and progression of atherosclerosis. Unfortunately, in these patients the atherogenic potential of dyslipidemia may depend more on apolipoproteins than on lipid abnormalities, and may not always be recognized by measurement of plasma lipids alone. The aim of this review was therefore to analyze the main lipid alterations that can occur in nephropathic patients, as well as their causes and their effects on the cardiovascular system. The clinical evidence and recommendations for the use of lipid-regulating drugs in patients with chronic kidney disease, nephrotic syndrome, in patients undergoing hemo- and peritoneal dialysis and in transplanted patients was also reviewed. Moreover, we analyzed the link between dyslipidemia and kidney disease onset and progression and the role of statins in preventing it

    Multiannual assessment of the desert dust impact on air quality in Italy combining PM10 data with physics-based and geostatistical models

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    Desert dust storms pose real threats to air quality and health of millions of people in source regions, with associated impacts extending to downwind areas. Europe (EU) is frequently affected by atmospheric transport of desert dust from the Northern Africa and Middle East drylands. This investigation aims at quantifying the role of desert dust transport events on air quality (AQ) over Italy, which is among the EU countries most impacted by this phenomenon. We focus on the particulate matter (PM) metrics regulated by the EU AQ Directive. In particular, we use multiannual (2006–2012) PM10 records collected in hundreds monitoring sites within the national AQ network to quantify daily and annual contributions of dust during transport episodes. The methodology followed was built on specific European Commission guidelines released to evaluate the natural contributions to the measured PM-levels, and was partially modified, tested and adapted to the Italian case in a previous study. Overall, we show that impact of dust on the yearly average PM10 has a clear latitudinal gradient (from less than 1 to greater than 10 µg/m3 going from north to south Italy), this feature being mainly driven by an increased number of dust episodes per year with decreasing latitude. Conversely, the daily-average dust-PM10 (≅12 µg/m3) is more homogenous over the country and shown to be mainly influenced by the site type, with enhanced values in more urbanized locations. This study also combines the PM10 measurements-approach with geostatistical modelling. In particular, exploiting the dust-PM10 dataset obtained at site- and daily-resolution over Italy, a geostatistical, random-forest model was set up to derive a daily, spatially-continuous field of desert-dust PM10 at high (1-km) resolution. This finely resolved information represent the basis for a follow up investigation of both acute and chronic health effects of desert dust over Italy, stemming from daily and annual exposures, respectively.This work was performed as an ‘After-LIFE’ activity of the EU LIFE+2010 DIAPASON project (LIFE+10 ENV/IT/391) and is a contributing activity to the COST Action InDust (CA16202) and to the EU ERA4CS project DustClim (Grant n. 690462). We thank the Barcelona Supercomputing Center (BSC, http://www.bsc.es/earth-sciences/mineral-dust-forecast-system/) for maintaining the BSC-DREAM8b daily dust forecasts used in this study. S. Basart acknowledges AXA Research Fund for supporting the long-term mineral dust research at the Earth Sciences Department at BSC. N. Alvan Romero carried out this research during an internship at ISAC-CNR under the supervision of F. Barnaba. Constructive comments by Jorge Pey and two other anonymous Reviewers are also gratefully acknowledged.Peer ReviewedPostprint (published version
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