Search

This article presents a numerical sequential approach to predict the geometry of the weld line, the heat transfer, the dimension of the heat-affected zone, and the stress-strain fields in automated gas metal arc welding (GMAW). The integrated simulation approach has been implemented by using commercial software tools, and it has been applied to simulate nine welding cases study. The achieved outcomes have been compared to the measurements and the microscope observations of weldings produced experimentally, in order to validate the prediction capability of the model with respect to the filler material deposition, the heat-affected zone size, and the distortion of the welded materials. [ABSTRACT FROM AUTHOR]

An accurate estimation of the radionuclide inventory of vitrified high-level waste is a prerequisite to assessing the radiological consequences of its geological disposal. The inventories of 34 radionuclides in this waste are provided by the waste producer for individual canisters at the time of loading/delivery. Of these, the inventories of 25 nuclides are measured directly during vitrification and the others are determined by calculation and/or correlation to measured contents. One purpose of the present work was to cross-check between the average and maximum radionuclide inventories of vitrified waste produced at the same facility in La Hague for Switzerland and Germany as of the data sets reported by the producer for 364 and 3017 canisters, respectively. Long-term safety assessments of geological repositories require the average and maximum inventories of a further 23 nuclides in addition to the 34 reported ones, which should be estimated by calculation or some correlation based on the technical specifications of the waste and of the reprocessing and vitrification processes. Another purpose of this work was therefore to cross-check these inventories and methods for their estimation as used by NAGRA and GRS. The results of this comparison show a good agreement for nuclides provided by the waste producer. The long-term safety relevant fission products show an agreement within 8%. The actinides have been found to show an agreement within 19%. The comparison between nuclides estimated on the basis of technical specifications shows higher deviations. The reasons for these discrepancies are addressed here. [ABSTRACT FROM AUTHOR]

The use of platelet-rich plasma (PRP) has become a strategic therapy in tissue regeneration medicine. PRP represents a good source of growth factors. Due to this property, it has been considered a reliable adjunctive material in bone augmentation procedures, such as the sinus lift technique. The aim of this review was to assess the scientific evidence on the effectiveness of PRP as an adjunctive material in the sinus floor elevation technique. The following databases were searched for relevant published studies: Medline, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, Science Direct, ISI Web of Knowledge, and SCOPUS. Only randomized controlled clinical trials comparing a group receiving PRP as an adjunctive material to a control group without PRP, involving adult human subjects (age >18 years) with no systemic disease, were included. Of the studies identified, only one reported a significant difference in bone augmentation in favour of the adjunctive use of PRP, while four studies did not find any significant difference. None of the studies included reported a significant difference in the implant survival rate. Further randomized clinical trials are needed to clarify the effectiveness of adjunctive PRP. [ABSTRACT FROM AUTHOR]

In this paper we present the most innovative aspects of the EC-FP7 EcoThermo project. The main aim of the project consists on innovating the technique of heat cost allocation in buildings with a centralized heating system, overcoming the heat cost allocator drawbacks for reliability, measurement reproducibility and traceability and contexts of applications. Given the complexity of the project, we will focus on its main aspects, such as the use of a virtual sensor to estimate the radiators heating power, the design of electronic valves fitted out with an energy harvesting system and the original wireless communication protocol. [ABSTRACT FROM AUTHOR]

Abstract: A tomographic measurement station has been designed and developed for the investigation of light water reactor spent fuel rod segments. A unique feature of the station is that it allows both γ-ray transmission and emission computerised tomography to be performed on individual fresh or burnt fuel rods. The basics of the tomographic station design, construction and operation are presented together with the results of four burnt UO2 fuel rod segments investigated, with rod average burnups of 54, 71, 91 and 121 MWd kg−1. The combination of transmission and emission tomography techniques performed on an individual object provides a synergetic experimental approach. By performing transmission tomography, not only the average material density but also detailed spatial distributions of the density and of the γ-ray linear attenuation coefficient have been determined for each sample. By performing emission tomography, the determination of within-rod internal radial distributions of 134Cs, 137Cs and 154Eu has also been achieved for each individual pin. The results have indicated large central depressions in the caesium distributions because of isotope migration, with varying magnitude from sample to sample. Finally and in addition to the tomographic reconstructions, the possibility to use single isotope activities, and/or isotopic concentration ratios from 134Cs, 137Cs, and 154Eu, as burnup indicators at very high and ultra-high burnups, has also been investigated. This paper presents in a comprehensive manner the large panel of analysis performed for this interesting set of spent fuel samples which represents a valuable experimental insight in the physics of ultra-high burnups. [Copyright &y& Elsevier]

Abstract: Peritoneal carcinomatosis (PC) from gastric cancer is a condition with a very bleak prognosis. Most authors consider it to be a terminal disease and recommend palliative therapy only. Multimodal therapeutic approaches to PC have emerged in the last decades, combining cytoreductive surgery (CRS) and peritonectomy procedures with perioperative intraperitoneal chemotherapy (IPEC), including hyperthermic intraperitoneal chemotherapy (HIPEC) and/or early postoperative intraperitoneal chemotherapy (EPIC). We reviewed the pertinent literature concerning the HIPEC modality both for the treatment of established PC and the prevention of peritoneal recurrence after potentially curative gastric cancer (GC) surgery. Basically, the two procedures relate to different aspects of GC and they are not comparable, since the latter has been used as an adjuvant when PC is still not macroscopically evident and the former has been exclusively used in advanced gastric cancer stages with peritoneal dissemination. Data supporting beneficial effects once gastric PC is already manifest is scarce and limited to few centres with specific experience in this field. Conversely, with regards to the peritoneal perfusion for preventing PC in high risk gastric cancer patients, there are phase III trials and meta-analysis which support beneficial effects resulting from the HIPEC procedure. To offer a baseline guide, we summarized the actual status and general outcome obtained by this multimodal technique, in association or not with CRS as treatment of advanced GC. [Copyright &y& Elsevier]

This paper presents the results of an experimental investigation to determine the effects of cryogenic coolant on surface integrity in orthogonal machining of hardened AISI 52100 bearing steel. Experiments were performed under dry and cryogenic conditions using chamfered CBN tool inserts. Several experimental techniques were used in the analyzing of the machined surface and subsurface: optical and scanning electron microscopes (SEM) were utilized for the surface topography characterization; chemical characterization (phase study) was carried out by means of Energy-dispersive spectroscopy (EDS) techniques; and X-ray diffraction (XRD) technique was used to determine residual stresses and phase changes induced by dry and cryogenic machining. The results show the benefits and the future potential of cryogenic cooling for surface integrity enhancement to achieve improved product's functional performance in hard machining. [ABSTRACT FROM AUTHOR]

In this paper an experimental investigation was conducted to determine the effects of the tool cutting-edge geometry, workpiece hardness, cutting speed, and microstructural changes (white and dark layers) on the residual stresses in dry orthogonal hard machining of AISI 52100 steel. X-ray diffraction technique was used to obtain in-depth residual stresses profiles in both axial and circumferential directions. The results show that tool geometry, workpiece hardness and cutting parameters significantly affect the surface residual stress, maximum compressive residual stress below the machined surface and its location. Moreover, microstructural analysis shows that thermally-induced phase transformations have a significant impact on the magnitude and location of this maximum compressive residual stress peak. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To analyze our experience with D3 lymphadenectomy in the treatment of advanced GC with specific reference to post-operative morbidity and mortality, incidence of para-aortic node (PAN) metastases, and long-term prognosis. Methods: Short- and long-term results of D3 lymphadenectomy were analyzed in 286 patients with advanced GC. Results: PAN metastases were demonstrated in 37 patients. PAN involvement was significantly higher in upper third tumours (29%) compared to middle and lower third (7%; P < 0.001). Eighty patients developed post-operative complications, being pulmonary disorders (6%), abdominal abscesses (4.5%) and pancreatic fistulas (3%) the most frequently observed. In-hospital mortality was 2%. Overall 5-year survival rate for R0 pT2-4 patients was 52%. When considering survival in relation to nodal involvement, both pN3 and non-regional lymph node metastases (M1a) patients showed a chance of long-term survival: 5-year survival was 31% for pN3 and 17% for M1a cases. Furthermore, the 5-year survival rate was remarkably high (about 60%) even in pN2 and pN3 subsets when no serosal invasion (pT2) was demonstrated. Conclusions: D3 lymphadenectomy could be further explored in specialized centers for curative surgery of advanced GC, especially for upper third tumours, providing that an acceptable morbidity and no increase in mortality can be offered. [Copyright &y& Elsevier]

Abstract: Aim: The purpose of this prospective observational study was to analyze the role of Mib-1 immunostaining as a proliferation index in breast cancer. Correlations between Mib-1 expression and clinico-pathological characteristics as well as its prognostic value have been studied in a series of 432 node negative breast cancers. Methods: Mib-1 expression was evaluated by immunohistochemistry. Tumor sections from highly cellular invasive areas of cancer were stained by monoclonal antibody Mib-1 (Dako) and cells whose nuclei stained positive were counted in 10 randomly chosen HPFs and expressed as percentages of all epithelial cells. A minimum of 400 cells were counted. Correlation between Mib-1 staining and clinico-pathological factors was investigated by means of univariate and multivariate analyses. The prognostic impact on actuarial disease free (DFS) and overall survival (OS) was evaluated by univariate analysis using the log-rank test and by multivariate analysis using Cox regression model. Results: Tumors were considered as positive for Mib-1 expression when more than 15% of cells counted were stained. Mib-1 positivity was found in 190/432 cases and resulted in being significantly related to tumor grade, tumor size and absence of estrogen receptors at multivariate analysis. With a median follow-up of 66 months, Mib-1 positivity resulted in being the only independent predictor of OS (RR 2.92), and an independent predictor of DFS (RR 2.01) together with absence of estrogen receptors (RR 2.15). Conclusions: Mib-1 index of proliferative activity correlates well to other established prognostic factors of breast cancer. Mib-1 index may improve the tailoring of adjuvant therapy in early breast cancer, and our experience adds evidence to its effectiveness as prognostic factor. Efforts to reach uniformity in the methodology and in the scoring system should be done to warrant a standardized procedure and make Mib-1 determination definitively reliable in the current clinical practice. [Copyright &y& Elsevier]

Abstract: Non-destructive and destructive methods have been compared to validate their corresponding assessed accuracies in the measurement of 134Cs/137Cs and 154Eu/137Cs isotopic concentration ratios in four spent UO2 fuel samples with very high (52 and 71GWd/t) and ultra-high (91 and 126GWd/t) burnup values, and about 10 (in the first three samples) and 4 years (in the latter sample) cooling time. The non-destructive technique tested was high-resolution gamma spectrometry using a high-purity germanium detector (HPGe) and a special tomographic station for the handling of highly radioactive 400mm spent fuel segments that included a tungsten collimator, lead filter (to enhance the signal to Compton background ratio and reduce the dead time) and paraffin wax (to reduce neutron damage). The non-destructive determination of these isotopic concentration ratios has been particularly challenging for these segments because of the need to properly derive non-Gaussian gamma-peak areas and subtract the background from perturbing capture gammas produced by the intrinsic high-intensity neutron emissions from the spent fuel. Additionally, the activity distribution within each pin was determined tomographically to correct appropriately for self-attenuation and geometrical effects. The ratios obtained non-destructively showed a 1σ statistical error in the range 1.9–2.9%. The destructive technique used was a high-performance liquid chromatographic separation system, combined online to a multicollector inductively coupled plasma mass spectrometer (HPLC-MC-ICP-MS), for the analysis of dissolved fuel solutions. During the mass spectrometric analyses, special care was taken in the optimisation of the chromatographic separation for Eu and the interfering element Gd, as also in the mathematical correction of the 154Gd background from the 154Eu signal. The ratios obtained destructively are considerably more precise (1σ statistical error in the range 0.4–0.8% for most of the samples, but up to 2.8% for one sample). The HPGe gamma spectrometry can achieve a high degree of accuracy (agreement with HPLC-MC-ICP-MS within a few percent), only by virtue of the optimised setup, and the refined measurement strategy and data treatment employed. [Copyright &y& Elsevier]

Abstract: A measurement station has been built for the non-destructive investigation of burnt fuel rod segments through high-resolution gamma spectrometry. Four UO2 pressurised water reactor fuel rod segments with different burnup levels between 50 and >100GWd/t and ⩽10 year cooling time have been experimentally characterised using gamma-ray spectrometry to determine 134Cs, 137Cs and 154Eu and their corresponding concentration ratios. Experimental errors of ∼2% (1σ) for the 134Cs/137Cs ratio were obtained for most of the segments. In parallel, pin cell depletion calculations have been performed for each segment using the deterministic code CASMO-4. Measured and calculated ratios have then been compared with the purpose of deriving and validating pin-averaged single-ratio burnup indicators for very high burnups. It is shown that the 134Cs/137Cs ratio, frequently used as a burnup monitor, is considerably less precise for values exceeding 50GWd/t; discrepancies of ∼16% are found between measured and calculated values, increasing with burnup up to ∼23%. The ratios built with the 154Eu concentration show even much larger discrepancies, essentially because this isotope is rather poorly predicted as revealed by just using different basic cross section data. [Copyright &y& Elsevier]

Abstract: Ureteral stricture and ureteral leakage are the most common early urological complications after kidney transplantation causing decreased urine output and increased serum creatinine and blood urea nitrogen. We report our experience with internal-external ureteral stent placement and ureteroplasty. Materials and Methods: From August 1999 to January 2005, we treated nine patients presenting with stricture or leak. After an anterograde pyelogram, an internal-external nephrostomy catheter was inserted in all patients; in four patients we also performed ureteroplasty. Results: The stricture and leak appeared from 12 to 93 days after kidney transplantation (mean = 39 ± 29 days). After a mean of 80 ± 43 days (range 25–141 days), the stent was successfully removed in seven patients (77%); no patient had a recurrence. The success was confirmed by a decline in serum creatinine (from 3.7 ± 1.4 to 1.6 ± 0.7 mg/dL) and blood urea nitrogen (from 54 ± 24 to 28 ± 7 mg/dL) with resolution of hydronephrosis on sonography. No procedure-related complications were observed. Surgical correction was necessary in two patients due to the persistence of a stricture. At long-term follow-up (50 ± 17 months), seven kidneys were still functioning and two had failed due to chronic rejection. Conclusion: Nephrostomy catheter placement and ureteroplasty are safe, effective alternatives to surgery to treat early ureteral complications after kidney transplantation. Interventional radiology procedures reducing the morbidity and the likelihood of loss of graft function may improve graft and patient survival. [Copyright &y& Elsevier]

The histo-blood group antigens P, P1 and Pk are a closely related set of glycosphingolipid structures expressed by red blood cells and other tissues. None of these three characters is expressed on p cells, a null phenotype that arises in the context of homozygous mutation of the A4GALT gene. Subjects with p phenotype spontaneously develop a natural alloantibody named anti-PP1Pk, which is a mixture of IgG and IgM against P1, P and Pk. While anti-P1 is a weak cold antibody with poor clinical significance, anti-P and anti-Pk antibodies are potent haemolysins responsible for severe hemolytic transfusion reactions. The rare anti-PP1Pk alloantibodies are associated with recurrent spontaneous abortion in the first trimester of gestation. P and Pk antigens are expressed at high levels on the placenta and antibodies directed against both these structures are deleterious to placental trophoblasts. Here we describe the use of plasma exchange (PEX) in a nulliparous 39-year-old woman with anti-PP1Pk antibodies and a history of repeated spontaneous early abortions and hypofertility. The patient underwent apheresis starting from the third week throughout the pregnancy and a healthy child was delivered by cesarean section at 35 WG. The newborn required only phototherapy within a few days of life. We can state that an early treatment with the only PEX has proven to be effective and safe in the management of a fetomaternal P-incompatibility caused by a high anti-PP1Pk titer (256). [ABSTRACT FROM AUTHOR]

We report details of the experience from the largest Italian program with hepatic living donation, focusing particularly on the use of intraoperative ultrasound in liver transplantation and living donation. During a 12-year period we changed our surgical technique in the conventional open procedures thanks to the experience gained into the laparoscopic setting. Intraoperative ultrasound has been implemented during these delicate procedures for ensuring a fast and safer detection of the accessory veins and final severing of the vascular stumps during liver transection. [ABSTRACT FROM AUTHOR]