Search

Skorohod and Olevsky's constitutive relation for viscous sintering (SOVS) is employed to simulate the shrinkage and relative density evolution of ceramics during the sintering process. While this model effectively simulates shrinkage and density evolution, the original formulation of the SOVS model does not explicitly incorporate grain growth or microstructural evolution. This paper introduces an enhanced version of the SOVS model, incorporating a novel calibration method to obtain the temperature dependence of the viscosity parameter. It considers grain growth as well as the evolution of the microstructure by adding new parameters. Simulations were conducted using Code_Aster, an open-source finite element software, in conjunction with MFront, a tool for formulating material behaviour equations. Dilatometer tests were performed with probes of porcelain stoneware composition to calibrate the model. The predictions of dimensional shrinkage and relative density evolution showed a high accuracy of the model (> 95%), enabling its use in the manufacturing process. [ABSTRACT FROM AUTHOR]

The interactive documentary field has a collaborative dimension since its beginning. This research proposes a model for the analysis of the participation of online communities within interactive documentary, developed on the basis of the previous scientific literature on this topic. Then, analysed case studies have shown the diversity of forms regarding contribution from online communities. On the basis of the different trends observed, five participative designs with different intensities and purposes have been described. Finally, the model has been applied to each design for its evaluation, allowing us to conclude that a significant participation would have to combine several of these designs considering the articulation of participant communities around documentary as well as its contribution to documentary meaning. [ABSTRACT FROM AUTHOR]

Nonlinear dynamics of cancer recurrence are known to be governed by several factors as initial tumour size, number of metastatic sites, or quantity of drug resistant cells. The precise extent and location of tumours are very important factors so quantitative and consistent methods of evaluation are needed to assess reponse to patient therapy. Whole-body 123I-metaiodobenzylguanidine (mIBG) scintigraphy is used as primary medical image modality to detect neuroblastoma tumours due to its high specificity and sensitivity. However, current oncological guidelines are based on qualitative observer-dependent analysis. This fact makes it difficult to compare results of scintigraphies taken at different moments during therapy or at different institutions. In this paper, we review analytical methods used in neuroblastoma detection and propose an observer-independent method to quantitatively analyse a 123I-mIBG scintigraphy. [ABSTRACT FROM AUTHOR]

The Large Hadron Collider (LHC) is presently under installation at CERN, Geneva. The approximately 4000 superconducting corrector magnets required by the machine are powered through copper-stabilized Nb-Ti busbars. To interconnect the magnets along the machine, about 50 000 joints between superconducting cables rated at 600 A have to be performed in-situ during the interconnection activities. An ultrasonic welding technique has been developed and optimized by CERN which led to the development of a dedicated machine which was qualified during the assembly of the STRING II, a 110-m chain of cryomagnets assembled as a prototype of the LHC. The realization of the ‘series’ interconnections together with the procurement of the tooling based on functional specifications have been contracted to a consortium of firms. Qualification tests and acceptance criteria in terms of electrical contact resistance, mechanical resistance, reliability and reproducibility have been defined by CERN. This paper presents the tests and some results of the qualification process relevant to the industrialized tooling provided by the contractor. Results of pre-series junctions done in the LHC tunnel are presented together with the perspective for the continuation of the work. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to develop a tool for evaluating person-centered therapeutic relationships within physiotherapy services, and to examine the content validity of the same. Methods: A mixed qualitative and quantitative study was performed in three distinct phases: 1) the items were generated based on a literature review and a content analysis of focus groups of patients and physiotherapists; 2) an e-Delphi survey process was performed based on three rounds to select and refine the proposed questionnaire; 3) two rounds of cognitive interviews were conducted to evaluate the comprehension of items, the clarity of language and the appropriateness and relevance of content. Results: Thirty-one items were generated based on the seven domains identified after the analysis of four focus groups of physiotherapists and four patient focus groups. Nine experts participated in the e-Delphi survey. Fifty-five patients participated in the two rounds of the cognitive pre-tests. Participating patients were from public and private physical therapy services. Based on the participants' suggestions, four items were removed, and four were added, whereas 16 were reworded. Conclusions: The final tool comprised 31 items divided into seven domains. The response format was based on a 5-point Likert frequency scale. The response options ranged from "strongly agree" to "strongly disagree". [ABSTRACT FROM AUTHOR]

Background Hepatic venous pressure gradient (HVPG) monitoring of therapy to prevent variceal rebleeding provides strong prognostic information. Treatment of nonresponders to β-blockers ± nitrates has not been clarified. Aim To assess the value of HVPG-guided therapy using nadolol + prazosin in nonresponders to nadolol + isosorbide-5-mononitrate (ISMN) compared with a control group treated with nadolol + ligation. Methods Cirrhotic patients with variceal bleeding were randomized to HVPG-guided therapy ( n = 30) or nadolol + ligation ( n = 29). A Baseline haemodynamic study was performed and repeated within 1 month. In the guided-therapy group, nonresponders to nadolol + ISMN received nadolol and carefully titrated prazosin and had a third haemodynamic study. Results Nadolol + prazosin decreased HVPG in nonresponders to nadolol + ISMN ( P < 0.001). Finally, 74% of patients were responders in the guided-therapy group vs. 32% in the nadolol + ligation group ( P < 0.01). The probability of rebleeding was lower in responders than in nonresponders in the guided therapy group ( P < 0.01), but not in the nadolol + ligation group ( P = 0.41). In all, 57% of nonresponders rebled in the guided-therapy group and 20% in the nadolol + ligation group ( P = 0.05). The incidence of complications was similar. Conclusions In patients treated to prevent variceal rebleeding, the association of nadolol and prazosin effectively rescued nonresponders to nadolol and ISMN, improving the haemodynamic response observed in controls receiving nadolol and endoscopic variceal ligation. Our results also suggest that ligation may rescue nonresponders. [ABSTRACT FROM AUTHOR]

Background Coronary revascularization surgery does not traditionally employ angiography to assess procedural success. Early graft failure is reported up to 30% in one year (JAMA Nov 2005) may relate to technical errors or conduit problems. We hypothesize that intra-operative assessment of graft by angiography identifies graft defects and may improve the long term graft survival. Methods We have developed one of the first hybrid operation room in the USA. In one year period 203 consecutive patients (age:63+/−16, M/F:126/39) underwent coronary revascularization with angiography before decannulation. Results Of 436 grafts, 72 angiographic defects were detected in 69 grafts (17% of total grafts). There were 11% conduit defects, 3% anastomotic defects, and 3% target vessel error. Of 72 defects, 25/72 defects required minor revision, 47/72 required either surgical or percutaneous intervention. Intra-operative angiography added an average 20+/−12 minutes to the surgery and 112+/−56 ml contrast. Renal function at 24hours and 48 hours after procedure did not vary significantly between patients who did vs. those did not have revisions. There were no significant differences in cardiopulmonary bypass time, aortic cross clamp time, and length of hospital stay for patients who underwent revision compared to those who did not. Renal function, bleeding complication, transfusion were similar in patients with percutaneous vs. surgical revision. Conclusions Intraoperative graft angiography performed at the time of CABG identifies graft defects, allowing for immediate surgical or percutaneous revision. Long-term study is in progress to assess whether intra-operative completion angiography decreases the rate of early graft failure. [ABSTRACT FROM AUTHOR]

Objective We developed a technique for mitral valve surgery through an ultra small (5 cm) right lateral thoracotomy without aortic cross clamp. This study reports our combined ST. Thomas and Vanderbilt Heart Institutes five years experience with this technique. Methods Six hundred and twenty five (316 M /309 F; aged 22–75 mean of 62 years) underwent ultra minimally invasive mitral valve surgery between August 2000 and June 2006. Through a 5 centimeter right lateral thoracotomy along the 4th intercostal space access to the pericardium and the left atrium was gained. Cardiopulmonary bypass was instituted through femoral cannulation. Under cold fibrillatory arrest (28°C) without aortic cross clamp, mitral valve repair (n = 196) or replacement (n = 380), in addition to mitral valve procedure we performed tricuspid valve repair (n = 69), ASD/PFO closure (n = 201) and Maze (n = 156). Mean pre operative New York Heart Association function class was 2.2 ± 0.9. Twenty eight patients had ejection fraction less than 20%. Results Thirty-day mortality was 1.28% (n = 8), Operating time, bypass time operating averaged 189 ± 52, 113 ± 35 minutes, respectively. Three patients had conversion to sternotomy. Fifteen patients (2.4%) underwent reexploration for bleeding. Average length of hospital stay from surgery to discharge was 6.85 ± 3 days. Ten patients (1.6%) had neurological events. Renal failure required hemodialysis in 5 patients (0.81%). Long term follow-up results are awaited. Conclusions This study demonstrate that this simplified technique of ultra minimally invasive mitral valve surgery is reproducible and provides the least invasive operative approach with low mortality and morbidity with good cosmetic results. [ABSTRACT FROM AUTHOR]