2,469 research outputs found

    Studio di conglomerati bituminosi con granulato di gomma proveniente da pneumatici dismessi

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    La ricerca di conglomerati bituminosi di elevate prestazioni sovente si associa allo studio delle implicazioni ambientali che la produzione, la posa in opera e l’esercizio di tali materiali comportano. Un aspetto assai importante, in tal senso, è l’opportunità che alcune modalità produttive offrono in termini di un ridotto consumo di inerti e del contestuale impiego di materiali destinati a discarica che, invece, vengono inseriti in processi di riciclaggio. È questo il caso della gomma proveniente dal riciclaggio industriale di pneumatici dismessi che, negli Stati Uniti ed in Canada, è divenuta una fonte sostanziosa per la realizzazione di conglomerati bituminosi. La presente ricerca, dopo una preliminare e sintetica descrizione del granulato di gomma e delle sue proprietà chimico-fisiche, si propone di evidenziare sperimentalmente il comportamento meccanico di conglomerati bituminosi per strati di base confezionati in laboratorio con l’aggiunta di questo componente, mediante i noti processi Dry e Wet, elaborati e combinati secondo opportuni criteri metodologici. In particolare l’indagine verte su prove inserite nell’attuale normativa italiana, con l’obiettivo di pervenire ad un quadro rappresentativo dell’influenza del granulato sulle caratteristiche meccaniche analizzate

    A dissipated energy comparison to evaluate fatigue resistance using 2PB

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    Flexural fatigue due to repeated traffic loading is a process of cumulative damage and one of the main failure modes of flexible pavement structures. Typically, micro-cracks originate at the bottom of an asphalt concrete layer due to horizontal tensile strains. Micro-cracking starts to propagate towards the upper layers under repeated loading which can lead to pavement failure. Different approaches are usually used to characterise fatigue resistance in asphalt mixtures including the phenomenological approach, the fracture mechanics approach and the dissipated energy approach. This paper presents a comparison of fatigue resistance calculated for different dissipated energy models using 2 Point Bending (2PB) at IFSTTAR in Nantes. 2PB tests have been undertaken under different loading and environmental conditions in order to evaluate the properties of the mixtures (stiffness, dissipated energy, fatigue life and healing effect)

    Manometric evaluation of internal anal sphincter after fissurectomy and anoplasty for chronic anal fissure: a prospective study

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    Chronic anal fissure (CAF) is a common painful clinical disease and its pathogenesis remains poorly understood. After failure of pharmacological therapy, that is the first-line treatment, sur- gical sphincterotomy remains the treatment of choice although it is followed by a high rate of anal incontinence resulting from the sphincter damage; therefore, the research of a sphincter-saving surgical option has become an important goal. The aim of this study was to evaluate the mano- metric modifications and the incidence of anal incontinence after fissurectomy and anoplasty with advancement skin flap in patients affected by CAF with hypertonia of the internal anal sphincter (IAS). Fifteen patients affected by CAF with hypertonia of IAS, unresponsive to medical therapy, were enrolled. All subjects underwent fissurectomy and anoplasty with advancement skin flap. Anorectal manometry was performed preoperatively and after 6 and 12 months from surgery. Maximum resting pressure (MRP), maximum squeeze pressure (MSP), ultraslow wave activity (USWA), fissure healing, anal continence, and postoperative complications were recorded. All patients healed within 30 days from surgery. No intra- or postoperative complications were recorded except for a case of partial donor site break. No significant modifications of MSP were detected. Six months after surgery, MRP was higher with respect to healthy subjects but signif- icantly reduced in comparison to baseline levels. At 12 months, it was higher have versus 6-month values but significantly lower versus preoperative values. USWA was significantly represented in patients with CAF versus healthy subject. Both at 6 and 12 months, they decreased significantly with respect to preoperative values without significant differences versus healthy subjects. Both at 6 and 12 months, anal continence did not differ with respect to preoperative time. The fissurectomy with anoplasty resulted in a high healing rate without surgical sequelae or anal incontinence. Also, it was able to reduce IAS pressure in the same manner as surgical sphincterotomy or forceful dilatation

    Acute inflammatory response in the subcutaneous versus periprosthethic space after incisional hernia repair: an original article

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    BACKGROUND: The acute inflammatory response following mesh implantation has been often evaluated in vitro and in animal models. The aim of this study was to evaluate the acute inflammatory response near the prosthesis in human by analysing some inflammatory indicators.METHODS: We used a cohort of twelve male patients affected by midline incisional hernia, who were admitted for surgical mesh repair. A suction drain was placed between the mesh and rectal muscles whereas, the other one was placed between the subcutaneous tissue and the oblique external sheath. The acute inflammatory response was analyzed by measuring the production of interleukin [IL]-1, IL-10, IL-1ra, C-Reactive Protein (CRP), total proteins, albumin and pH in the drain fluids.RESULTS: The dynamics of CRP and ILs production resulted similar in both drainages. Comparing drain over mesh and subcutaneous drain at all times, IL-1 and CRP values always resulted significantly higher in the first one, whereas IL-1ra and IL-10 values were significantly higher in the last one. Total protein and albumin were similar in both drains at all time; only in the drain over mesh fluid, pH values resulted significantly reduced in the fourth post-operative day.CONCLUSIONS: Our data showed that an acute inflammatory reaction is present in both sites examined. However, it was significantly higher in the space after mesh implantation

    Concomitant Small Cell Neuroendocrine Carcinoma of Gallbladder and Breast Cancer

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    The neuroendocrine carcinoma is defined as a high-grade malignant neuroendocrine neoplasm arising from enterochromaffin cells, usually disposed in the mucosa of gastric and respiratory tracts. The localization in the gallbladder is rare. Knowledge of these gallbladder tumors is limited and based on isolated case reports. We describe a case of an incidental finding of small cell neuroendocrine carcinoma of the gallbladder, observed after cholecystectomy for cholelithiasis, in a 55-year-old female, who already underwent quadrantectomy and sentinel lymph-node biopsy for breast cancer. The patient underwent radiotherapy for breast cancer and six cycles of chemotherapy with cisplatin and etoposide. Eighteen months after surgery, the patient was free from disease. Small cell neuroendocrine carcinoma of the gallbladder has poor prognosis. Because of the rarity of the reported cases, specific prognostic factors have not been identified. The coexistence of small cell neuroendocrine carcinoma of the gallbladder with another malignancy has been reported only once.The contemporary presence of the two neoplasms could reflect that bioactive agents secreted by carcinoid can promote phenotypic changes in susceptible cells and induce neoplastic transformation

    Pseudo-label refinement using superpixels for semi-supervised brain tumour segmentation

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    Training neural networks using limited annotations is an important problem in the medical domain. Deep Neural Networks (DNNs) typically require large, annotated datasets to achieve acceptable performance which, in the medical domain, are especially difficult to obtain as they require significant time from expert radiologists. Semi-supervised learning aims to overcome this problem by learning segmentations with very little annotated data, whilst exploiting large amounts of unlabelled data. However, the best-known technique, which utilises inferred pseudo-labels, is vulnerable to inaccurate pseudo-labels degrading the performance. We propose a framework based on superpixels - meaningful clusters of adjacent pixels - to improve the accuracy of the pseudo labels and address this issue. Our framework combines superpixels with semi-supervised learning, refining the pseudo-labels during training using the features and edges of the superpixel maps. This method is evaluated on a multimodal magnetic resonance imaging (MRI) dataset for the task of brain tumour region segmentation. Our method demonstrates improved performance over the standard semi-supervised pseudo-labelling baseline when there is a reduced annotator burden and only 5 annotated patients are available. We report DSC=0.824 and DSC=0.707 for the test set whole tumour and tumour core regions respectively

    Pseudo-label refinement using superpixels for semi-supervised brain tumour segmentation

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    Training neural networks using limited annotations is an important problem in the medical domain. Deep Neural Networks (DNNs) typically require large, annotated datasets to achieve acceptable performance which, in the medical domain, are especially difficult to obtain as they require significant time from expert radiologists. Semi-supervised learning aims to overcome this problem by learning segmentations with very little annotated data, whilst exploiting large amounts of unlabelled data. However, the best-known technique, which utilises inferred pseudo-labels, is vulnerable to inaccurate pseudo-labels degrading the performance. We propose a framework based on superpixels - meaningful clusters of adjacent pixels - to improve the accuracy of the pseudo labels and address this issue. Our framework combines superpixels with semi-supervised learning, refining the pseudo-labels during training using the features and edges of the superpixel maps. This method is evaluated on a multimodal magnetic resonance imaging (MRI) dataset for the task of brain tumour region segmentation. Our method demonstrates improved performance over the standard semi-supervised pseudo-labelling baseline when there is a reduced annotator burden and only 5 annotated patients are available. We report DSC=0.824 and DSC=0.707 for the test set whole tumour and tumour core regions respectively

    Highly selective toxic and proapoptotic effects of two dimeric ribonucleases on thyroid cancer cells compared to the effects of doxorubicin

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    The lack of selectivity of conventional antitumour drugs against cancer cells is responsible for their high toxicity. The development of new tumour-specific drugs is therefore highly needed. We tested the cytotoxic effects and the nature of cell death induced by a naturally dimeric bovine RNase and a newly engineered dimeric human RNase upon three genetically well-defined normal and malignant thyroid cell systems. RNases effects were compared with those of doxorubicin, a conventional antineoplastic drug. Our results show significant and selective proapoptotic effects exerted on tumour cells by both RNases, the strength of their cytotoxic and apoptotic activity being directly related to the degree of cell malignancy. No toxic effects were observed upon normal cells. Doxorubicin showed, instead, cytotoxic and apoptotic effects also against normal cells. The in vitro results were corroborated by the antitumour action of both dimeric RNases towards a malignant human thyroid tumour grown in nude mice. These results indicate a selective action of dimeric RNases against cancer cells and suggest the potential application of these molecules or their derivatives to the treatment of aggressive subtypes of thyroid cancer

    Age- and sex-related variations in platelet count in Italy: a proposal of reference ranges based on 40987 subjects' data

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    BACKGROUND AND OBJECTIVES: Although several studies demonstrated that platelet count is higher in women, decreases with age, and is influenced by genetic background, most clinical laboratories still use the reference interval 150-400×10(9) platelets/L for all subjects. The present study was to identify age- and sex-specific reference intervals for platelet count. METHODS: We analysed electronic records of subjects enrolled in three population-based studies that investigated inhabitants of seven Italian areas including six geographic isolates. After exclusion of patients with malignancies, liver diseases, or inherited thrombocytopenias, which could affect platelet count, reference intervals were estimated from 40,987 subjects with the non parametric method computing the 2.5° and 97.5° percentiles. RESULTS: Platelet count was similar in men and women until the age of 14, but subsequently women had steadily more platelets than men. The number of platelets decreases quickly in childhood, stabilizes in adulthood, and further decreases in oldness. The final result of this phenomenon is that platelet count in old age was reduced by 35% in men and by 25% in women compared with early infancy. Based on these findings, we estimated reference intervals for platelet count ×10(9)/L in children (176-452), adult men (141-362), adult women (156-405), old men (122-350) and, old women (140-379). Moreover, we calculated an extended reference interval that takes into account the differences in platelet count observed in different geographic areas. CONCLUSIONS: The age-, sex-, and origin-related variability of platelet count is very wide, and the patient-adapted reference intervals we propose change the thresholds for diagnosing both thrombocytopenia and thrombocytosis in Italy

    Effects of L-carnitine administration on left ventricular remodeling after acute anterior myocardial infarction: The L-carnitine Ecocardiografia Digitalizzata Infarto Miocardico (CEDIM) trial

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    Objectives. This study was performed to evaluate the effects of l-carnitine administration on long-term left ventricular dilation in patients with acute anterior myocardial infarction. Background. Carnitine is a physiologic compound that performs an essential role in myocardial energy production at the mitochondrial level. Myocardial carnitine deprivation occurs during ischemia, acute myocardial infarction and cardiac failure. Experimental studies have suggested that exogenous carnitine administration during these events has a beneficial effect on function. Methods. The l-Carnitine Ecocardiografia Digitalizzata Infarto Miocardico (CEDIM) trial was a randomized, double-blind, placebo-controlled, multicenter trial in which 472 patients with a first acute myocardial infarction and high quality two-dimensional echocardiograms received either placebo (239 patients) or l-carnitine (233 patients) within 24 h of onset of chest pain. Placebo or l-carnitine was given at a dose of 9 g/day intravenously for the first 5 days and then 6 g/day orally for the next 12 months. Left ventricular volumes and ejection fraction were evaluated on admission, at discharge from hospital and at 3, 6 and 12 months after acute myocardial infarction. Results. A significant attenuation of left ventricular dilation in the first year after acute myocardial infarction was observed in patients treated with l-carnitine compared with those receiving placebo. The percent increase in both end-diastolic and endsystolic volumes from admission to 3-, 6- and 12-mouth evaluation was significantly reduced in the l-carnitine group. No significant differences were observed in left ventricular ejection fraction changes over time in the two groups. Although not designed to demonstrate differences in clinical end points, the combined incidence of death and congestive heart failure after discharge was 14 (6%) in the l-carnitine treatment group versus 23 (9.6%) in the placebo group (p = NS). Incidence of ischemic events during follow-up was similar in the two groups of patients. Conclusions. l-Carnitine treatment initiated early after acute myocardial infarction and continued for 12 months can attenuate left ventricular dilation during the first year after an acute myocardial infarction, resulting in smaller left ventricular volumes at 3, 6 and 12 months after the emergent event
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