7,718 research outputs found

    On the stability and convergence of a semi-discrete discontinuous Galerkin scheme to the kinetic Cucker–Smale model

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    We study analytical properties of a semi-discrete discontinuous Galerkin (DG) scheme for the kinetic Cucker–Smale (CS) equation. The kinetic CS equation appears in the mean-field limit of the particle CS model and it corresponds to the dissipative Vlasov type equation approximating the large particle CS system. For this proposed DG scheme, we show that it exhibits analytical properties such as the conservation of mass, L2 -stability and convergence to the sufficiently regular solution, as the mesh-size tends to zero. In particular, we verify that the convergence rate of the DG numerical solution to the sufficiently regular kinetic solution is dependent on the Sobolev regularity of the kinetic soluiton. We also present several numerical simulations for low-dimensional cases

    Usefulness of regional right ventricular and right atrial strain for prediction of early and late right ventricular failure following a left ventricular assist device implant: A machine learning approach

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    Background: Identifying candidates for left ventricular assist device surgery at risk of right ventricular failure remains difficult. The aim was to identify the most accurate predictors of right ventricular failure among clinical, biological, and imaging markers, assessed by agreement of different supervised machine learning algorithms. Methods: Seventy-four patients, referred to HeartWare left ventricular assist device since 2010 in two Italian centers, were recruited. Biomarkers, right ventricular standard, and strain echocardiography, as well as cath-lab measures, were compared among patients who did not develop right ventricular failure (N = 56), those with acute–right ventricular failure (N = 8, 11%) or chronic–right ventricular failure (N = 10, 14%). Logistic regression, penalized logistic regression, linear support vector machines, and naïve Bayes algorithms with leave-one-out validation were used to evaluate the efficiency of any combination of three collected variables in an “all-subsets” approach. Results: Michigan risk score combined with central venous pressure assessed invasively and apical longitudinal systolic strain of the right ventricular–free wall were the most significant predictors of acute–right ventricular failure (maximum receiver operating characteristic–area under the curve = 0.95, 95% confidence interval = 0.91–1.00, by the naïve Bayes), while the right ventricular–free wall systolic strain of the middle segment, right atrial strain (QRS-synced), and tricuspid annular plane systolic excursion were the most significant predictors of Chronic-RVF (receiver operating characteristic–area under the curve = 0.97, 95% confidence interval = 0.91–1.00, according to naïve Bayes). Conclusion: Apical right ventricular strain as well as right atrial strain provides complementary information, both critical to predict acute–right ventricular failure and chronic–right ventricular failure, respectively

    Hemp Flour Particle Size Affects the Quality and Nutritional Profile of the Enriched Functional Pasta

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    The rheological and chemical quality of pasta samples, which were obtained using the durum wheat semolina fortified with the hemp seed solid residue, after oil extraction, sieved at 530 mu m (Hemp 1) or 236 mu m (Hemp 2) at different percentages of substitution (5%, 7.5%, and 10%, were evaluated. The total polyphenolic content in hemp flour was quantified in the range of 6.38-6.35 mg GAE/g, and free radical scavenging was included in the range from 3.94-3.75 mmol TEAC/100 g in Hemp 1 and Hemp 2, respectively. The phenolic profiles determined by UHPLC-ESI/QTOF-MS showed that cannabisin C, hydroxycinnamic and protocatechuic acids were the most abundant phenolic compounds in both hemp flours. Among the amino acids, isoleucine, glutamine, tyrosine, proline, and lysine were the most abundant in raw materials and pasta samples. Although the hemp seeds were previously subjected to oil extraction, hemp flours retain about 8% of oil, and the fatty acids present in the largest amount were linoleic acid and alpha-linolenic acid. Characterization of the minerals showed that the concentration of macro and trace elements increased according to fortification percentage. Sensory evaluation and cooking quality indicated that the best performance in terms of process production and consumer acceptance was obtained using Hemp 2 at 7.5%. Hemp supplementation could be a potential option for producing high-quality, nutritionally rich, low-cost pasta with good color and functionality

    Immuno-inflammatory activation in acute cardio-embolic strokes in comparison with other subtypes of ischaemic stroke

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    Few studies have examined the relationship between inflammatory biomarker blood levels, cardioembolic stroke subtype and neurological deficit. So the aim of our study is to evaluate plasma levels of immuno-inflammatory variables in patients with cardio-embolic acute ischaemic stroke compared to other diagnostic subtypes and to evaluate the relationship between immuno-inflammatory variables, acute neurological deficit and brain infarct volume. One hundred twenty patients with acute ischaemic stroke and 123 controls without a diagnosis of acute ischaemic stroke were evaluated. The type of acute ischaemic stroke was classified according to the TOAST classification. We evaluated plasma levels of IL-1beta, TNF-alpha, IL-6 and IL-10, E-selectin, P-selectin, sICAM-1,sVCAM-1, vWF, TPA and PAI-1. Patients with ischaemic stroke classified as cardio-embolic (CEI) showed, compared to other subtypes, significantly higher median plasma levels of TNF-alpha , IL-6 and IL-1beta. Furthermore stroke patients classified as lacunar showed, compared to other subtypes, significantly lower median plasma levels of TNF-alpha, IL-6 and IL-1beta. Multiple linear regression showed a significant association between the Scandinavian Stroke Scale (SSS) score at admission and diagnostic subtype, infarct volume of cardio-embolic strokes and some inflammatory variables. Our findings confirm that cardio-embolic strokes have a worse clinical presentation and produce larger and more disabling strokes than other ischaemic stroke subtypes reporting a possible explanation of higher immuno-inflammatory activation of the acute phase.Few studies have examined the relationship between inflammatory biomarker blood levels, cardioembolic stroke subtype and neurological deficit. So the aim of our study is to evaluate plasma levels of immuno-inflammatory variables in patients with cardio-embolic acute ischaemic stroke compared to other diagnostic subtypes and to evaluate the relationship between immuno-inflammatory variables, acute neurological deficit and brain infarct volume. One hundred twenty patients with acute ischaemic stroke and 123 controls without a diagnosis of acute ischaemic stroke were evaluated. The type of acute ischaemic stroke was classified according to the TOAST classification. We evaluated plasma levels of IL-1beta, TNF-alpha, IL-6 and IL-10, E-selectin, P-selectin, sICAM-1,sVCAM-1, vWF, TPA and PAI-1. Patients with ischaemic stroke classified as cardio-embolic (CEI) showed, compared to other subtypes, significantly higher median plasma levels of TNF-alpha , IL-6 and IL-1beta. Furthermore stroke patients classified as lacunar showed, compared to other subtypes, significantly lower median plasma levels of TNF-alpha, IL-6 and IL-1beta. Multiple linear regression showed a significant association between the Scandinavian Stroke Scale (SSS) score at admission and diagnostic subtype, infarct volume of cardio-embolic strokes and some inflammatory variables. Our findings confirm that cardio-embolic strokes have a worse clinical presentation and produce larger and more disabling strokes than other ischaemic stroke subtypes reporting a possible explanation of higher immuno-inflammatory activation of the acute phase. Comment in Inflammatory markers for ischaemic stroke. [Thromb Haemost. 2009

    Vortex dynamics in rotating counterflow and plane Couette and Poiseuille turbulence in superfluid Helium

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    An equation previously proposed to describe the evolution of vortex line density in rotating counterflow turbulent tangles in superfluid helium is generalized to incorporate nonvanishing barycentric velocity and velocity gradients. Our generalization is compared with an analogous approach proposed by Lipniacki, and with experimental results by Swanson et al. in rotating counterflow, and it is used to evaluate the vortex density in plane Couette and Poiseuille flows of superfluid helium.Comment: 18 pages, 2 figure

    Folding mechanisms steer the amyloid fibril formation propensity of highly homologous proteins

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    Significant advances in the understanding of the molecular determinants of fibrillogenesis can be expected from comparative studies of the aggregation propensities of proteins with highly homologous structures but different folding pathways. Here, we fully characterize, by means of stopped-flow, T-jump, CD and DSC experiments, the unfolding mechanisms of three highly homologous proteins, zinc binding Ros87 and Ml153-149 and zinc-lacking Ml452-151. The results indicate that the three proteins significantly differ in terms of stability and (un)folding mechanisms. Particularly, Ros87 and Ml153-149 appear to be much more stable to guanidine denaturation and are characterized by folding mechanisms including the presence of an intermediate. On the other hand, metal lacking Ml452-151 folds according to a classic two-state model. Successively, we have monitored the capabilities of Ros87, Ml452-151 and Ml153-149 to form amyloid fibrils under native conditions. Particularly, we show, by CD, fluorescence, DLS, TEM and SEM experiments, that after 168 hours, amyloid formation of Ros87 has started, while Ml153-149 has formed only amorphous aggregates and Ml452-151 is still monomeric in solution. This study shows how metal binding can influence protein folding pathways and thereby control conformational accessibility to aggregation-prone states, which in turn changes aggregation kinetics, shedding light on the role of metal ions in the development of protein deposition diseases

    Description of ionospheric disturbances observed by Vertical Ionospheric Sounding at 3 MHz

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    High Frequency radio waves reflected by the ionosphere can provide a relevant amount of information within the composite received signal. The ionosphere is indeed a frequency dispersive, bi-refractive, absorbing medium, in which multipath propagation occurs due to disturbance on a varied time-spatial scale. On the time-spatial level of Small Scale Disturbances (SSD) the ionosphere dynamics, detectable by Vertical Ionospheric Sounding (VIS), is mainly dependent on wrinkled layers acting as multi-reflectors. The present paper discusses different aspects of the effects of multipath fading suffered by the wave along the propagation path and potentially associated with SSD. To achieve these objectives, a VIS campaign at a fixed frequency of 3.0 MHz was conducted at the ionospheric observatory in Rome (Latitude 41.8 N; Longitude 12.5 E), by collecting a series of measurements of the power variations in received echo signals recorded between two consecutive ionograms whose sounding repetition rate was set to 15 min. The obtained results show that: 1) the fading suffered by the wave follows either a Rayleigh trend or a Nakagami-Rice trend, or a mix of them, the mixed case being the most frequent (about 65 % of the analysed cases); 2) the predominant periodicities characterizing the power variation are less than 25 s; such values are compatible with the small scale ionospheric disturbances; 3) for all the 24 hours of the day the ionospheric reflector is pretty stable and for time intervals of 10-30 s the periods of stability occur with a percentage of occurrence ranging between 55% and 95 %; for time intervals of 190- 210 s the periods of stability occur instead with a percentage of occurrence ranging between 5% and 54 %

    Opuntia cladodes as functional ingredient in durum wheat bread: rheological, sensory, and chemical characterization

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    Cladodes are considered by-products of Opuntia ficus-indica cultivation. Their addition as source of antioxidants to durum wheat breads could have effects on preventing cardiovascular diseases, cancers, and inflammation. The inclusion of 0-5-10-15% cladodes, harvested in three different locations, on quality and antioxidant properties of fortified durum wheat breads has been evaluated. The enrichment with 10% of cladodes resulted in an increase in the content of total phenolics (14.8 vs 2.7 mg GAE/100 g of control bread), a decrease of IC50 (3.28 vs 49.7 mg/ml of control bread), good rheological characteristics of loaves and largely positive evaluation by panel test. Fortification with 15% of cladodes caused an increase in the resistance to the mixture with a reduction of dough extensibility. In addition, the evaluation of different populations of Opuntia gave information about the valorization of the crop and could be a strategy to increase bioactive compounds in durum wheat breads

    Effects of clinical and laboratory variables and of pretreatment with cardiovascular drugs in acute ischaemic stroke: a retrospective chart review from the GIFA study.

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    Background: Few studies have examined the role of cardiovascular drugs on acute ischaemic stroke prognosis. Aims: To evaluate the relationship between a favourable outcome in patients with acute ischaemic stroke and specific demographic, clinical and laboratory variables and cardiovascular drug pretreatment. Methods: The 1096 patients enrolled in the GIFA study (who had a main discharge diagnosis of ischaemic stroke) represent the final patient sample used in this analysis. Drugs considered in the analysis included angiotensin converting enzyme (ACE)-inhibitors, angiotensin II receptor blockers, statins, calcium channel blockers, anti-platelet drugs, vitamin K antagonists and heparins. The outcomes analyzed included in-hospital mortality, cognitive function evaluated by the Hodkinson Abbreviated Mental Test (HAMT), and functional status evaluated by activities of daily living (ADL). The definition of a good outcome was no in-hospital mortality, a HAMT score of >= 6 and no ADL impairment. Results: Patients with no in-hospital mortality, a HAMT score of >6 and no ADL impairment were more likely to be younger at baseline and have a lower blood glucose level and a systolic blood pressure (SBP) between 120 and 180 mmHg, a higher plasma total cholesterol level, a lower white blood cell count, and a lower Charlson Index (CI) score, a higher rate of pretreatment with ACE-inhibitors, calcium channel blockers and a lower rate of pretreatment with heparin. Conclusions: Predictors of good outcome, in terms of in-hospital mortality and cognitive and functional performance at discharge, included higher SBP at admission between 120 and 180 mmHg, a SBP plasma total cholesterol levels, a lower CI score, and pretreatment with ACE-inhibitors, calcium channel blockers and anti-platelets. (C) 2010 Elsevier Ireland Ltd. All rights reserved
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