228 research outputs found

    Parallel meshing, discretization and computation of flow in massive discrete fracture networks

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    In the present work a message passing interface (MPI) parallel implementation of an optimization-based approach for the simulation of underground flows in large discrete fracture networks is proposed. The software is capable of parallel execution of meshing, discretization, resolution, and postprocessing of the solution. We describe how optimal scalability performances are achieved combining high efficiency in computations with an optimized use of MPI communication protocols. Also, a novel graph-topology for communications, called the multi-Master approach, is tested, allowing for high scalability performances on massive fracture networks. Strong scalability and weak scalability simulations on random networks counting order of 10^5 fractures are reported

    Phenobarbital does not worsen outcomes of neonatal hypoxia on hippocampal LTP on rats

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    IntroductionNeonatal hypoxia is a common cause of early-life seizures. Both hypoxia-induced seizures (HS), and the drugs used to treat them (e.g., phenobarbital, PB), have been reported to have long-lasting impacts on brain development. For example, in neonatal rodents, HS reduces hippocampal long-term potentiation (LTP), while PB exposure disrupts GABAergic synaptic maturation in the hippocampus. Prior studies have examined the impact of HS and drug treatment separately, but in the clinic, PB is unlikely to be given to neonates without seizures, and neonates with seizures are very likely to receive PB. To address this gap, we assessed the combined and separate impacts of neonatal HS and PB treatment on the development of hippocampal LTP.MethodsMale and female postnatal day (P)7 rat pups were subjected to graded global hypoxia (or normoxia as a control) and treated with either PB (or vehicle as a control). On P13-14 (P13+) or P29-37 (P29+), we recorded LTP of the Schaffer collaterals into CA1 pyramidal layer in acute hippocampal slices. We compared responses to theta burst stimulation (TBS) and tetanization induction protocols.ResultsUnder the TBS induction protocol, female rats showed an LTP impairment caused by HS, which appeared only at P29+. This impairment was delayed compared to male rats. While LTP in HS males was impaired at P13+, it normalized by P29+. Under the tetanization protocol, hypoxia produced larger LTP in males compared to female rats. PB injection, under TBS, did not exacerbate the effects of hypoxia. However, with the tetanization protocol, PB – on the background of HS – compensated for these effects, returning LTP to control levels.DiscussionThese results point to different susceptibility to hypoxia as a function of sex and age, and a non-detrimental effect of PB when administered after hypoxic seizures

    TUSC (TUrbinate Surgery Classification): A Novel Classification Proposal for Turbinate Surgery

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    Aim of this manuscript is to propose a clear and easily applicable classification for turbinate surgery, based on the use of a numerical model, which could be introduced in the practice of Otolaryngologists and Maxillo-Facial surgeons.Applying this classification, it will be possible to offer an easy format when describing which turbinates are involved in a procedure, and to offer a quick method to record and analyse clinical data, also for scientific purpose

    Finite-top-mass effects in NNLO Higgs production

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    We construct an accurate approximation to the exact NNLO cross section for Higgs production in gluon-gluon fusion by matching the dominant finite top mass corrections recently computed by us to the known result in the infinite mass limit. The ensuing corrections to the partonic cross section are very large when the center of mass energy of the partonic collision is much larger than the Higgs mass, but lead to a moderate correction at the percent level to the total Higgs production cross section at the LHC. Our computation thus reduces the uncertainty related to these corrections at the LHC from the percent to the per mille level.Comment: 4 pages, 4 figures; to be published in the proceedings of QCD2008. Reference adde

    Atrial functional tricuspid regurgitation: a novel and underappreciated clinical entity

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    Abstract Functional or secondary tricuspid regurgitation (FTR) is a progressive disease with a significant negative impact on patient morbidity and mortality. Recently, atrial fibrillation (AF) has been recognized as a cause of FTR (with/without coexisting functional mitral regurgitation) by promoting right atrial (RA) remodeling and secondary tricuspid valve (TV) annulus dilation, even in the absence of right ventricular (RV) dilation or dysfunction. This distinct form of FTR has been called "atriogenic" or "atrial". Recent evidence suggests that the RA is an important player in FTR pathophysiology not only for patients with AF, but also for those in sinus rhythm. Preliminary reports on atrial FTR show that cardioversion with documented maintenance of sinus rhythm promotes TV annulus and RA reverse remodeling and may significantly reduce FTR severity at follow-up. Large-scale studies on the prognostic benefits of rhythm vs rate-control strategy in atrial FTR patients are needed to substantiate specific guidelines indications for this subset of patients

    Alternative Applications of Trans-Oral Robotic Surgery (TORS): A Systematic Review

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    The role of robotic surgery in the field of oncology has been widely described, in particular for the tumours of the oropharynx and larynx, but its efficacy for benign pathology is inconsistent

    GABA A Receptor α1 Subunit Deletion Prevents Developmental Changes of Inhibitory Synaptic Currents in Cerebellar Neurons

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    Developmental changes in miniature IPSC (mIPSC) kinetics have been demonstrated previously in cerebellar neurons in rodents. We report that these kinetic changes in mice are determined primarily by developmental changes in GAB

    Impact of reboxetine plus oxybutynin treatment for obstructive sleep apnea on cardiovascular autonomic modulation

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    The combination of noradrenergic (reboxetine) plus antimuscarinic (oxybutynin) drugs (reb-oxy) reduced obstructive sleep apnea (OSA) severity but no data are available on its effects on cardiac autonomic modulation. We sought to evaluate the impact of 1-week reb-oxy treatment on cardiovascular autonomic control in OSA patients. OSA patients were randomized to a double-blind, crossover trial comparing 4 mg reboxetine plus 5 mg oxybutynin to a placebo for OSA treatment. Heart rate (HR) variability (HRV), ambulatory blood pressure (BP) monitoring (ABPM) over 24 h baseline and after treatment were performed. Baroreflex sensitivity was tested over beat-to-beat BP recordings. 16 subjects with (median [interquartile range]) age 57 [51–61] years and body mass index 30 [26–36]kg/m2 completed the study. The median nocturnal HR was 65 [60–69] bpm at baseline and increased to 69 [64–77] bpm on reb-oxy vs 66 [59–70] bpm on placebo (p = 0.02). The mean 24 h HR from ABPM was not different among treatment groups. Reb-oxy administration was not associated with any modification in HRV or BP. Reb-oxy increased the baroreflex sensitivity and did not induce orthostatic hypotension. In conclusion, administration of reb-oxy did not induce clinically relevant sympathetic overactivity over 1-week and, together with a reduction in OSA severity, it improved the baroreflex function

    Performance of non-invasive respiratory function indices in predicting clinical outcomes in patients hospitalized for COVID-19 pneumonia in medical and sub-intensive wards: a retrospective cohort study

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    Coronavirus disease 2019 (COVID-19) is a newly recognized infectious disease which can lead to acute respiratory distress syndrome requiring ventilatory support and intensive care unit admission. The aim of our study is to evaluate the performance of two non-invasive respiratory function indices (the ROX index and the SatO2/FiO2 ratio), as compared to the traditional PaO2/FiO2 ratio, in predicting a clinically relevant composite outcome (death or intubation) in hospitalized patients for COVID-19 pneumonia. Four hospital centers in Northern Italy conducted an observational retrospective cohort study during the first wave of COVID-19 pandemic. Four hundred and fifty-six patients with COVID-19 pneumonia admitted to medical or sub-intensive wards were enrolled. Clinical, laboratory, and respiratory parameters, for the calculation of different indices, were measured at hospital admission. In medical wards (Verona and Padua) the PaO2/FiO2 ratio, ROX index and SatO2/FiO2 ratio were able to predict intubation or death with good accuracy (AUROC for the PaO2/FiO2 ratio, ROX index and SatO2/FiO2 ratio of 75%, 75% and 74%, respectively). Regarding sub-intensive wards (Milan and Mantua), none of the three respiratory function indices was significantly associated with the composite outcome. In patients admitted to medical wards for COVID-19 pneumonia, the ROX index and the SatO2/FiO2 ratio demonstrated not only good performance in predicting intubation or death, but their accuracy was comparable to that of the PaO2/FiO2 ratio. In this setting, where repeated arterial blood gas tests are not always feasible, they could be considered a reliable alternative to the invasive PaO2/FiO2 ratio
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