102 research outputs found

    Unusual clinical presentation of primary aortoduodenal fistula

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    Primary aorto-enteric fistula (PAEF) develops between the native aorta and the gastro-intestinal tract, in the presence of an abdominal aortic aneurysm. It is a rare, life-threatening condition and appears to be less frequent than secondary aorto- enteric fistula, which is associated with previous aortic prosthetic reconstruction. When untreated, the overall mortality rate is almost 100%. Diagnosis may be challenging until the occurrence of a massive haemorrhage. In the presence of gross contamination, patients tend to a worse prognosis. Extra-anatomical bypass and repair of the enteric tract is the treatment of choice in case of gross contamination. In situ reconstruction is often reported in cases of mild bacterial contamination. Endovascular treatment has recently become a valid option in haemodynamically unstable patients, but a staged approach, with delayed surgical treatment, seems advisable

    Measurement of the structural behaviour of a 3D airless wheel prototype by means of optical non-contact techniques

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    Additive Manufacturing (AM) is becoming a widely employed technique also in mass production. In this field, compliances with geometry and mechanical performance standards represent a crucial constrain. Since 3D printed products exhibit a mechanical behaviour that is difficult to predict and investigate due to the complex shape and the inaccuracy in reproducing nominal sizes, optical non-contact techniques are an appropriate candidate to solve these issues. In this paper, 2D digital image correlation and thermoelastic stress analysis are combined to map the stress and the strain performance of an airless wheel prototype. The innovative airless wheel samples are 3D-printed by fused deposition modelling and stereolithography in poly-lactic acid and photopolymer resin, respectively. The static mechanical behaviour for different wheel-ground contact configurations is analysed using the aforementioned non-contact techniques. Moreover, the wheel-ground contact pressure is mapped, and a parametric finite element model is developed. The results presented in the paper demonstrate that several factors have great influence on 3D printed airless wheels: a) the type of material used for manufacturing the specimen, b) the correct transfer of the force line (i.e., the loading system), c) the geometric complexity of the lattice structure of the airless wheel. The work confirms the effectiveness of the proposed non-contact measurement procedures for characterizing complex shaped prototypes manufactured using AM

    Spatial resource wars: A two region example

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    We develop a spatial resource model in continuous time in which two agents strategically exploit a mobile resource in a two-location setup. In order to contrast the overexploitation of the resource (the tragedy of commons) that occurs when the player are free to choose where to fish/hunt/extract/harvest, the regulator can establish a series of spatially structured policies. We compare the three situations in which the regulator: (a) leaves the player free to choose where to harvest; (b) establishes a natural reserve where nobody is allowed to harvest; (c) assigns to each player a specific exclusive location to hunt. We show that when preference parameters dictate a low harvesting intensity, the policies cannot mitigate the overexploitation and in addition they worsen the utilities of the players. Conversely, in a context of harsher harvesting intensity, the intervention can help to safeguard the resource, preventing the extinction and also improving the welfare of both players

    Tamoxifen in treatment of hepatocellular carcinoma: a randomised controlled trial

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    Background Results from small randomised trials on tamoxifen in the treatment of hepatocellular carcinoma (HCC) are conflicting, We studied whether the addition of tamoxifen to best supportive care prolongs survival of patients with HCC. Methods Patients with any stage of HCC were eligible, irrespective of locoregional treatment. Randomisation was centralised, with a minimisation procedure accounting for centre, evidence of disease, and time from diagnosis. Patients were randomly allocated best supportive care alone or in addition to tamoxifen, Tamoxifen was given orally, 40 mg per day, from randomisation until death. Results 496 patients from 30 institutions were randomly allocated treatment from January, 1995, to January, 1997. Information was available for 477 patients. By Sept 15, 1997, 119 (50%) of 240 and 130 (55%) of 237 patients had died in the control and tamoxifen arms, respectively. Median survival was 16 months and 15 months (p=0.54), respectively, No differences were found within subgroups defined by prognostic variables. Relative hazard of death for patients receiving tamoxifen was 1.07 (95% CI 0.83-1.39). Interpretation Our findings show that tamoxifen is not effective in prolonging survival of patients with HCC
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