222 research outputs found

    A method for yield and cycle time improvements in Al alloy casting with enhanced conductivity steel for die construction

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    A die for Al alloy casting must be designed to achieve the expected quality levels. Moreover, the casting unit cost must be regarded as the objective function to be minimised It can be expressed as a function of the quantity of materials and energy to be used, cycle time and equipment investment. This work compares the performance of the die with inserts manufactured using the usual 1.2343 steel with that of the innovative 1.2383. The latter is considered due to its enhanced thermal conductivity, despite being more expensive. Simulation experiments are designed to evaluate different die layouts. The quality design solutions are evaluated against the cost objective function in order to identify the optimal die choice. A case study on gravity die casting (GDC) of an AlSi7Mg0.3 engine head shows faster solidification dynamics when using 1.2383 instead of 1.2343 steel. This reduces the feeder volume, thus increasing the production yield and speeding up the cycle time with a leverage effect. The higher investment cost for the inserts is rapidly returned thanks to the reduction in variable costs. The Return On Investment (ROI) with the improved die in the new solution is short compared with the life of the die

    Radiation risks knowledge in resident and fellow in paediatrics: A questionnaire survey

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    Background: Analyse through a multi-choice anonymous questionnaire the knowledge's level in paediatric residents and fellows in two different main Italian hospital, looking mainly to the information to patients and relatives related to risks of ionizing radiation used in common radiological investigations in children. Methods: 65 multi choice questionnaires were distributed to paediatric residents and fellows of two different hospitals, an University Hospital (A.O.U.P. "P. Giaccone"- University of Palermo) and a national reference centre for paediatrics (Ospedale Pediatrico Bambino Gesù - Rome). The questionnaire included twelve multiple-choice questions with the aim of analyzing the knowledge about ionizing radiation related risks in infants and children who undergo common diagnostic radiology investigations. The data obtained were processed using software Stata/MP version 11.2. In order to measure the level of expertise of each interviewee a binary indicator was built. The value 1 was assigned if the percentage of correct answers exceeds the median of the distribution and 0 for values not exceeding the median. The association between the level of competence and demographic characteristics (gender, age) and training experience was measured by means of α2 test. Results: 51/65 questionnaires were completed, returned and analysed (87.7%). Only 18 surveyed (35%), (95% IC=[22%-48%]) can be defined as competent in radiation risk knowledge for common radiological investigations, considering the percentage of correct answers at least of 50% (sufficient knowledge was given with a minimum score of 8 correct answers out of 12). Conclusions: The study demonstrates an urgent need to implement the radiation protection knowledge in the training programme of paediatricians, that improve if just a short targeted training is performed

    INFLUENZA DELLA NITROCARBURAZIONE IONICA SULLA MICROSTRUTTURA E LA RESISTENZA A FATICA DI ACCIAI SINTERIZZATI

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    La nitrocarburazione al plasma di acciai sinterizzati conferisce resistenza superficiale e limita le variazioni dimensionali. Mentre le caratteristiche microstrutturali degli strati nitrurati, in linea generale, dipendono poco dal processo di produzione dell’acciaio sinterizzato, le proprietà risultanti, che sono una sintesi delle caratteristiche del materiale base e delle modifiche introdotte dalla nitrurazione, possono esserne influenzate anche significativamente. In questo lavoro, acciai sinterizzati di interesse per il settore dei trasporti, sono stati prodotti con parametri diversi, e sottoposti allo stesso trattamento di nitrocarburazione. E’ stata condotta l’analisi microstrutturale e sono state determinate le proprietà meccaniche, con particolare riferimento alla resistenza a fatica

    Non-perforated peptic ulcer disease: multidetector CT findings, complications, and differential diagnosis

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    Despite availability of effective therapies, peptic ulcer disease (PUD) remains a major global disease, resulting from a combination of persistent Helicobacter pylori infection and widespread use of nonsteroidal anti-inflammatory drugs. Albeit endoscopy definitely represents the mainstay diagnostic technique, patients presenting to emergency departments with unexplained abdominal pain generally undergo multidetector CT as an initial investigation. Although superficial ulcers generally remain inconspicuous, careful multiplanar CT interpretation may allow to detect deep ulcers, secondary mural and extraluminal signs of peptic gastroduodenitis, thereby allowing timely endoscopic verification and appropriate treatment. This pictorial essay aims to provide radiologists with an increased familiarity with CT diagnosis of non-perforated PUD, with emphasis on differential diagnosis. Following an overview of current disease epidemiology and complications, it explains the appropriate CT acquisition and interpretation techniques, and reviews with several examples the cross-sectional findings of uncomplicated PUD. Afterwards, the CT features of PUD complications such as ulcer haemorrhage, gastric outlet obstruction, biliary and pancreatic fistulisation are presented. Teaching points Gastric and duodenal peptic ulcers are increasingly caused by nonsteroidal anti-inflammatory drugs Multiplanar CT interpretation allows detecting deep ulcers and secondary signs of gastroduodenitis CT diagnosis of uncomplicated peptic disease relies on direct and indirect signs Currently the commonest complication, haemorrhage may be treated with transarterial embolisation Other uncommon complications include gastric outlet obstruction and biliopancreatic fistulisation

    Human equilibrative nucleoside transporter 1 and carcinoma of the ampulla of Vater: expression differences in tumour histotypes

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    The human equilibrative nucleoside transporter 1 (hENT1) is the major means by which gemcitabine enters human cells; recent evidence exists that hENT1 is expressed in carcinoma of the ampulla of Vater and that it should be considered as a molecular prognostic marker for patients with resected ampullary cancer. Aim of the present study is to evaluate the variations of hENT1 expression in ampullary carcinomas and to correlate such variations with histological subtypes and clinicopathological parameters. Forty-one ampullary carcinomas were histologically classified into intestinal, pancreaticobiliary and unusual types. hENT1 and Ki67 expression were evaluated by immunohistochemistry, and apoptotic cells were identified by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate biotin nick end labelling (TUNEL) method. hENT1 overexpression was detected in 63.4% ampullary carcinomas. A significant difference in terms of hENT1 and Ki67 expression was found between intestinal vs. pancreaticobiliary types (P=0.03 and P=0.009 respectively). Moreover, a significant statistical positive correlation was found between apoptotic and proliferative Index (P=0.036), while no significant correlation was found between hENT1 and apoptosis. Our results on hENT1 expression suggest that classification of ampullary carcinoma by morphological subtypes may represent an additional tool in prospective clinical trials aimed at examining treatment efficacy; in addition, data obtained from Ki67 and TUNEL suggest a key role of hENT1 in tumour growth of ampullary carcinoma

    Acute Fibrinous and Organising Pneumonia in Whipple’s disease

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    We report a case of acute fibrinous and organising pneumonia in Whipple’s disease with lung improvement after antibiotic therapy. In our knowledge this is the first report of Whipple’s disease with acute fibrinous and organising pneumonia

    Promyelocytic leukemia (PML) gene expression is a prognostic factor in ampullary cancer patients

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    BACKGROUND: Promyelocytic leukemia (PML) tumor suppressor gene plays a key role in acute PML pathogenesis but its involvement in pathogenesis and prognosis of solid cancers has not been defined yet. PATIENTS AND METHODS: In all, 62 ampullary adenocarcinoma patients who underwent curative surgery between 1996 and 2005 were included. Expression analysis of PML was carried out by immunohistochemical staining and correlated with disease-free survival (DFS) and overall survival (OS). RESULTS: In 24 tumor specimens (38.7%), PML was classified as absent, in 16 (25.8%) as focally expressed and in 22 (35.5%) as diffusely expressed. By univariate analysis, DFS was significantly influenced by pathological T stage (P=0.03), lymph nodal involvement (P=0.002), and PML expression (P=0.001). DFS in patients without PML expression was 28.0 months versus 45.1 and 75.5 for patients with focal and diffuse expression, respectively. OS in the group of patients without PML expression, with focal expression, and with diffuse expression was 40, 48, and 77 months, respectively (P=0.002). By a multivariate analysis, PML expression was the strongest prognostic factor for DFS (P=0.003) and the only statically significant prognostic factor for OS (P=0.009). CONCLUSIONS: Our preliminary data suggest PML as a novel prognostic tool for ampullary cancer patients

    Modified capitonage in partial cystectomy performed for liver hydatid disease: Report of 2 cases

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    BACKGROUND: Several techniques have been described in liver hydatid disease surgery, with most well known partial cystectomy, capitonage and introflexion. METHODS: We present a technical modification on open partial cystectomy for liver hydatid disease. We performed this operation in 2 patients with liver echinococcosis. The cyst is being unroofed and evacuated from the daughter cysts. The identified bile vessels ligated. The remnants of the anterior wall (capsule of the cyst) are anchored with sutures in the posterior wall in a manner that the cavity of the cyst disappears. RESULTS: In both patients the disease eradicated. No postoperative complications were observed including bile leaking and/or abscess formation. CONCLUSIONS: Our technique helps in the fast, and effective mobilization of the patient, as well as in the minimization of postoperative bile leaking
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