479 research outputs found

    Implementation of Non-Reflecting Boundary Conditions in a Finite Volume Unstructured Solver for the Study of Turbine Cascades

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    The analysis of component interaction in the turbomachinery field is nowadays of growing importance. This leads to the combination of different approaches, such as Large Eddy Simulation for combustors and Unsteady Reynolds-Averaged Navier-Stokes equations for turbines, and is responsible for the increase of both computational effort and required accuracy of the numerical tools. To guarantee accurate results and efficient convergence rates, numerical schemes must handle the spurious reflecting waves coming from the boundaries of truncated domains. This can be achieved by means of Non-Reflecting Boundary Conditions. The research activity described in the present paper is aimed at implementing the method of Non-Reflecting Boundary Conditions for the Linearized Euler Equations proposed by Giles in an in-house finite volume implicit time-marching solver. The methodology is validated using the available experimental data obtained at the von Karman Institute for Fluid Dynamics on the LS89 High-Pressure Turbine vane for both subsonic and transonic working condition. The implemented approach demonstrates its importance for the correct evaluation of the pressure distribution both on the vane surface and in the pitchwise direction when the computational domain is truncated at the experimental probe's position

    The Expander-Implant Breast Reconstruction in the COVID Era: Which is the “Unhappy” Tissue Expander Priority?

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    Breast surgeons seem to agree on the fact that a same-day surgery (mastectomy and breast reconstruction) protocol provides appropriate cancer treatment during times of unprecedented resource limitations, such as in the COVID era. In this scenario, pre-pectoral implant-based breast reconstruction can be definitively considered a sustainable technique. Nevertheless, the authors focus on the management of patients who had already undergone a same day procedure with two-stage breast reconstruction, implanting a breast tissue expander during the last two-year period and have been progressively delayed according to a surgical care based on priority. We coined the expression “unhappy tissue expander” to define all those symptomatic patients for which surgery should not be delayed even during an epidemic context. Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266

    Prostasome-like particles in stallion semen.

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    Human semen contains membranous vesicles called prosta- somes. They are secreted by the prostate gland and contain large amounts of cholesterol, sphingomyelin, and Ca2. Prostasomes enhance the motility of ejaculated spermatozoa and are in- volved in a number of additional biological functions. No prostasome-like vesicles have been described in horse se- men up to now. We have demonstrated the presence of pros- tasome-like vesicles in the equine semen and characterized them as to size, morphology, and lipid composition; we have found that they are similar to human prostasomes in many re- spects. We propose that these vesicles might be important for the fecundity of horse semen. This is of interest since the success of artificial insemination is limited by the fact that stallion sperm barely survive cryopreservation

    Continuous monitoring of cerebral oxygen saturation in elderly patients undergoing major abdominal surgery minimizes brain exposure to potential hypoxia

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    to develop cerebral desaturation because of the reduced physiologic reserve that accompanies aging. To evaluate whether monitoring cerebral oxygen saturation (rSO2) minimizes intraoperative cerebral desaturation, we prospectively monitored rSO2 in 122 elderly patients undergoing major abdominal surgery with general anesthesia. Patients were randomly allocated to an intervention group (the monitor was visible and rSO2 was maintained at 75% of preinduction values; n 56) or a control group (the monitor was blinded and anesthesia was managed routinely; n 66). Cerebral desaturation (rSO2 reduction 75% of baseline) was observed in 11 patients of the treatment group (20%) and 15 patients of the control group (23%) (P 0.82). Mean (95% confidence intervals) values of mean rSO2 were higher (66% [64%–68%]) and the area under the curve below 75% of baseline (AUCrSO2275% of baseline) was lower (0.4 min% [0.1– 0.8 min%]) in patients of the treatment group than in patients of the control group (61% [59%–63%] and 80 min% [2–144 min%], respectively; P 0.002 and P 0.017). When considering only patients developing intraoperative cerebral desaturation, a lower Mini Mental State Elimination (MMSE) score was observed at the seventh postoperative day in the control group (26 [25–30]) than in the treatment group (28 [26 –30]) (P 0.02), with a significant correlation between the AUCrSO2 75% of baseline and postoperative decrease in MMSE score from preoperative values (r20.25, P0.01). Patients of the control group with intraoperative cerebral desaturation also experienced a longer time to postanesthesia care unit (PACU) discharge (47 min [13–56 min]) and longer hospital stay (24 days [7–53] days) compared with patients of the treatment group (25 min [15–35 min] and 10 days [7–23 days], respectively; P 0.01 and P 0.007). Using rSO2 monitoring to manage anesthesia in elderly patients undergoing major abdominal surgery reduces the potential exposure of the brain to hypoxia; this might be associated with decreased effects on cognitive function and shorter PACU and hospital stay

    Economic aspects in the management of diabetes in Italy

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    Background: Diabetes mellitus (DM) is a chronic- degenerative disease associated with a high risk of chronic complications and comorbidities. The aim of this study is to estimate the average annual cost incurred by the Italian National Health Service (NHS) for the treatment of DM stratified by patients’ comorbidities. Moreover, the model estimates the economic impact of implementing good clinical practice for the management of patients with DM. Methods: Data were extrapolated from administrative database of the Marche Region and specific inclusion and exclusion criteria were developed from a clinical board in order to estimate patients with DM only, DM+1, DM+2, DM+3 and DM+4 comorbidities (cardiovascular disease, neuropathy, nephropathy and retinopathy). Regional data were considered a good proxy for implementing a previously developed cost-of- illness (COI) model from Italian NHS perspective already published. A scenario analysis was considered to estimate the economic impact of good clinical practice implementation in the treatment of DM and its comorbidities in Italy. Results: The model estimated an average number of patients with DM per year in the Marche region of 85.909 (5.5% of population) from 2008 to 2011. The mean costs per patients with DM only, DM+1, DM+2, DM+3 and DM+4 comorbidities were €341, €1,335, €2,287, €5,231 and €7,085 respectively. From the Italian NHS perspective, the total economic burden of DM in Italy amounted to €8.1. billion/year (22% for drugs, 74% for hospitalization and 4% for visits). Scenario analysis demonstrates that the implementation of good clinical practice could save over €700 million per year. Conclusions: This model is the first study that considers real world data and COI model to estimate the economic burden of DM and its comorbidities from the Italian NHS perspective. Integrated management of the patients with DM could be a good driver for the reduction of the costs of this disease in Italy

    Natural history and risk factors for diabetic kidney disease in patients with T2D: lessons from the AMD-annals

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    The Associazione Medici Diabetologi (AMD) annals initiative is an ongoing observational survey promoted by AMD. It is based on a public network of about 700 Italian diabetes clinics, run by specialists who provide diagnostic confirmation and prevention and treatment of diabetes and its complications. Over the last few years, analysis of the AMD annals dataset has contributed several important insights on the clinical features of type-2 diabetes kidney disease and their prognostic and therapeutic implications. First, non-albuminuric renal impairment is the predominant clinical phenotype. Even though associated to a lower risk of progression compared to overt albuminuria, it contributes significantly to the burden of end-stage renal disease morbidity. Second, optimal blood pressure control provides significant but incomplete renal protection. It reduces albuminuria but there may be a J curve phenomenon with eGFR at very low blood pressure values. Third, hyperuricemia and diabetic hyperlipidemia, namely elevated triglycerides and low HDL cholesterol, are strong independent predictors of chronic kidney disease (CKD) onset in diabetes, although the pathogenetic mechanisms underlying these associations remain uncertain. Fourth, the long-term intra-individual variability in HbA1c, lipid parameters, uric acid and blood pressure plays a greater role in the appearance and progression of CKD than the absolute value of each single variable. These data help clarify the natural history of CKD in patients with type 2 diabetes and provide important clues for designing future interventional studies
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