56 research outputs found

    Pile Performance Assessment under Induced Lateral Loading

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    This research work focuses on determining the internal force distribution in piles from displacement measurements when the piles no longer behave fully elastically. The method is based on the principle of virtual work (unit-load method) and allows the calculation of the bending moment distribution along piles, which is assumed to be the dominant internal force in bending. Four recent case studies were used, focusing either on liquefaction induced loading or on static induced plasticity. Comparison between the observed and calculated bending moments highlighted the method’s flexibility to derive accurate results in various soil conditions, length-size of experiment and load conditions. The method is also equally applicable to piles and to retaining walls. The maximum error between observed and calculated maximum bending moment ranged from 30% to less than 5% whereas the location of the maximum bending moment along the length of the pile was successfully calculated in all tests which stands promising for prediction of plastic hinges. The method can be used as a reliable-rapid tool to estimate the pile state following earthquake loading. This, in turn, can be used as a resilient and vulnerability indicator of the pile ability to resist further loading and continue to perform its function safely

    Multi-parametric investigation of the volcano-hydrothermal system at Tatun Volcano Group, Northern Taiwan

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    The Tatun Volcano Group (TVG) is located in northern Taiwan near the capital Taipei. In this study we selected and analyzed almost four years (2004–2007) of its seismic activity. The seismic network established around TVG initially consisted of eight three-component seismic stations with this number increasing to twelve by 2007. Local seismicity mainly involved high frequency (HF) earthquakes occurring as isolated events or as part of spasmodic bursts. Mixed and low frequency (LF) events were observed during the same period but more rarely. During the analysis we estimated duration magnitudes for the HF earthquakes and used a probabilistic non-linear method to accurately locate all these events. The complex frequencies of LF events were also analyzed with the Sompi method indicating fluid compositions consistent with a misty or dusty gas. We juxtaposed these results with geochemical/temperature anomalies extracted from fumarole gas and rainfall levels covering a similar period. This comparison is interpreted in the context of a model proposed earlier for the volcano-hydrothermal system of TVG where fluids and magmatic gases ascend from a magma body that lies at around 7–8 km depth. Most HF earthquakes occur as a response to stresses induced by fluid circulation within a dense network of cracks pervading the upper crust at TVG. The largest (<i>M</i><sub>L</sub> ~ 3.1) HF event that occurred on 24 April 2006 at a depth of 5–6 km had source characteristics compatible with that of a tensile crack. It was followed by an enrichment in magmatic components of the fumarole gases as well as a fumarole temperature increase, and provides evidence for ascending fluids from a magma body into the shallow hydrothermal system. This detailed analysis and previous physical volcanology observations at TVG suggest that the region is volcanically active and that measures to mitigate potential hazards have to be considered by the local authorities

    Malignant triton tumour of the anterior mediastinum as incidental finding

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    A rare case of malignant peripheral nerve sheath tumour with rhabdomyoblastic differentiation (malignant triton tumour) of the anterior mediastinum in a 30-yearold male is reported. The tumour was an incidental finding during the diagnostic work-up following a motor vehicle accident. The patient underwent median sternotomy with a tumour resection performed. Local relapse was suspected one month later, as per the chest CT-scan, and post-operative chemoradiation was applied, which produced a response. Twelve months later the patient is doing well while radiological findings remain invariable. Localization of a triton tumour in the anterior mediastinum is extremely rare, adjuvant treatment is necessary, recurrence frequently occurs and the prognosis is dismal

    Primary right atrium angiosarcoma mimicking pericarditis

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    <p>Abstract</p> <p>Background</p> <p>Primary cardiac neoplasms occur rarely and most of them are benign. Malignant tumors including angiosarcoma are extremely rare and have a non specific clinical presentation and a poor prognosis.</p> <p>Case presentation</p> <p>We present a case of a young male who was transferred to our hospital because of shock and multiple organ failure after a complicated pericardial biopsy. During the previous seven months he presented with recurrent episodes of pericardial effusions and tamponade. Chest computed tomography revealed a mass in the right atrium, infiltrating the myocardium and pericardium. During emergency surgery that followed, the patient died because of uncontrolled hemorrhage. Autopsy revealed the mass of the right atrium, which was identified on histological examination as primary cardiac angiosarcoma.</p> <p>Conclusion</p> <p>This case highlights the difficulties both in early diagnosis and in the management of patients with cardiac angiosarcoma.</p

    Predicting lymphoma in Sjogren's syndrome and the pathogenetic role of parotid microenvironment through precise parotid swelling recording

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    Objective Parotid swelling (PSW) is a major predictor of non-Hodgkin's lymphoma (NHL) in primary SS (pSS). However, since detailed information on the time of onset and duration of PSW is scarce, this was investigated to verify whether it may lead to further improved prediction. NHL localization was concomitantly studied to evaluate the role of the parotid gland microenvironment in pSS-related lymphomagenesis. Methods A multicentre study was conducted among patients with pSS who developed B cell NHL during follow-up and matched controls that did not develop NHL. The study focused on the history of salivary gland and lachrymal gland swelling, evaluated in detail at different times and for different durations, and on the localization of NHL at onset. Results PSW was significantly more frequent among the cases: at the time of first referred pSS symptoms before diagnosis, at diagnosis and from pSS diagnosis to NHL. The duration of PSW was evaluated starting from pSS diagnosis, and the NHL risk increased from PSW of 2-12 months to >12 months. NHL was prevalently localized in the parotid glands of the cases. Conclusion A more precise clinical recording of PSW can improve lymphoma prediction in pSS. PSW as a very early symptom is a predictor, and a longer duration of PSW is associated with a higher risk of NHL. Since lymphoma usually localizes in the parotid glands, and not in the other salivary or lachrymal glands, the parotid microenvironment appears to be involved in the whole history of pSS and related lymphomagenesis

    Prognostic significance of HER3 and HER4 protein expression in colorectal adenocarcinomas

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    BACKGROUND: Colorectal cancer remains a major cause of cancer mortality in the Western world. A limited number of studies has been conducted in respect of Her-3 and Her-4 expression and their correlation with clinical parameters and prognosis in colorectal carcinomas . In this study we sought to determine the pattern and the prognostic significance of HER-3 and HER-4 in colorectal adenocarcinoma. METHODS: We studied HER-3 and HER-4 protein expression in106 paraffin embedded specimens of primary colorectal tumors using immunohistochemistry. The pattern and protein expression levels of HER-3 and HER-4 were correlated with several clinical and pathological parameters. RESULTS: HER-3 staining displayed membranous and cytoplasmic expression pattern in 18 (17%) and 30 samples (28,3%), respectively. HER-4 membranous and cytoplasmic expression was found in 20 (18,9%) and 32 samples (30,2%), respectively. Specimens regarded as positive for HER-3 cytoplasmic expression were associated with moderate tumor grade (p = 0,032) and older median age (p = 0,010). Specimens regarded as positive for HER-4 membranous protein expression were associated with involved lymphnodes (p = 0,0003). Similar results were obtained when considering Her-3 and Her-4 protein expression irrespective of their cellular localization. There was no correlation between the expression of HER-3 and HER-4 and patients outcome. CONCLUSION: HER-4 membranous protein expression was found to predict for lymph nodes positivity in this cohort of patients with colorectal cancer.HER-4 expression status may identify tumors with aggressive biological behavior and increased metastatic potential
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