595 research outputs found
Experimental and numerical investigations on slender panels with holes under symmetrical localised loads
Perforated steel girders under a single or combined in plane loading have been largely studied in the literature. However, such investigations were trusted on the numerical modelling and FEM analysis and due to the lack of experimental results in most cases, the accuracy of the numerical model and the consideration of imperfections in the FEM analyses are open to reflexion. In this paper, a series of experimental tests are performed to study the post-critical behaviour of perforated steel girders. Ten full scales steel girders were tested under uniaxial compressive force. Amongst them, four were used as control specimens whereas a circular hole was located in the center of the other six. The parameters such as the geometry of the web plate, the position of the hole and the plate slenderness are found as those most influencing the post-critical behaviour. Finally, the experimental results were used to validate the intensive numerical analyses. The results obtained showed the strong influence of combined geometrical imperfections and residual stresses on the mid-plane Von Mises stresses
GASTRIC METASTASES ORIGINATING FROM OCCULT BREAST LOBULAR CARCINOMA: DIAGNOSTIC AND THERAPEUTIC PROBLEMS
BACKGROUND: Breast cancer is the most frequent malignant tumour to metastasize into the gastrointestinal tract in female and is second only to malignant melanoma. Nevertheless gastrointestinal metastases arising from breast cancer are quite rare. The upper gastrointestinal tract is more frequently involved and lobular infiltrating carcinoma has a greater predilection compared to the ductal type. CASE PRESENTATION: The authors describe the case of a 70 years old woman with a preoperative diagnosis of gastric undifferentiated medullary--type carcinoma, which was the first manifestation of an occult breast carcinoma. The primary site of carcinoma was identified with the use of a panel of selected immunohistochemical markers. CONCLUSION: Our goal in this case report is to increase the awareness of surgeons and clinicians to rule out the possibility of mammary origin in circumstance of gastric cancer occurring in female, even in patients without a previous or concurrent history of breast carcinoma. Although not a particularly common event, it is, nevertheless, reported in the literature. The differentiation between primary gastric carcinoma and metastatic breast carcinoma is essential for planning the correct therapeutic approach, in order to avoid the patient unnecessary surgery
APPLICATION OF DUPLEX STAINLESS STEEL FOR WELDED BRIDGE CONSTRUCTION IN AGGRESSIVE ENVIRONMENT
Maintenance costs are a significant item in life cycle of steel bridges, becoming of paramount importance in aggressive environments. The use of duplex stainless steels for bridge decks would be a major step forward in providing durable, low maintenance structures, exploiting both their corrosion resistance and high mechanical properties, capable of meeting in full the required structural safety performances. A research project partially funded by the EU research programme RFCS (Research Fund for Coal and Steel, Bridgeplex contract RFS-CR-04040) is developing technical information on the use of duplex stainless steel in welded bridge construction via mechanical testing and numerical analyses, so as to provide indications suitable to form the basis for an upgrade of Eurocode 3 [1] and to allow a reliable Life Cycle Cost analysis for this kind of structures so as to address the best material choice for the future bridges. The project is still in progress but first results are available. This paper gives an overview of the project and summarizes results obtained, deeper detailed in other papers presented at the International Conference Duplex 2007 ([5] and [6]). In particular the paper is concerned with: · overview of critical details in a welded bridge deck and relevant data available in literature also on austenitic and austeno-ferritic steels; and · economical evaluations considering maintenance aspects and fabrication costs showing the advantages of the application of duplex stainless steel to defined bridge typologies
Modulators of change-of-direction economy after repeated sprints in elite soccer players
Purpose: To investigate the acute effect of repeated-sprint activity (RSA) on change-of-direction economy (assessed using shuttle running economy [SRE]) in soccer players and explore neuromuscular and cardiorespiratory characteristics that may modulate this effect.
Methods: Eleven young elite male soccer players (18.5 [1.4] y old) were tested on 2 different days during a 2-week period in their preseason. On day 1, lower-body stiffness, power and force were assessed via countermovement jumps, followed by an incremental treadmill test to exhaustion to measure maximal aerobic capacity. On day 2, 2 SRE tests were performed before and after a repeated-sprint protocol with heart rate, minute ventilation, and blood lactate measured.
Results: Pooled group analysis indicated no significant changes for SRE following RSA due to variability in individual responses, with a potentiation or impairment effect of up to 4.5% evident across soccer players. The SRE responses to RSA were significantly and largely correlated to players’ lower-body stiffness (r = .670; P = .024), and moderately (but not significantly) correlated to players’ force production (r = −.455; P = .237) and blood lactate after RSA (r = .327; P = .326).
Conclusions: In summary, SRE response to RSA in elite male soccer players appears to be highly individual. Higher lower-body stiffness appears as a relevant physical contributor to preserve or improve SRE following RSA
Guillain-Barré syndrome : report of two rare clinical cases occurring after allergenic bone grafting in oral maxillofacial surgery
Guillaine-Barr\ue9 Syndrome (GBS), also known as post-infectious polyneuropathy or acute idiopathic polyneuritis, is an infrequent disorder of the peripheral nervous system. The cause of GBS is unknown. It has been associated in the past with microbial infections, vaccinations, surgical procedures and debilitation of the patient. The classic signs of GBS occurring in the two patients being reported here are muscle weakness, motor and sensory impairment and ascending paralysis with respiratory involvement. The documented cases involved GBS syndrome following oral and maxillofacial surgery in which allogeneic-banked freeze-dried bone have been utilized along with autogenous grafting. There were no incidents of viral infection, vaccination or the other prodromal incidents involved in these cases. It is believed that the description of these two cases would be of interest in that it may stimulate the reporting of similar anecdotal occurrences by other surgeons. Both patients fully recovered from the GBS and are presently alive and well
Schneider membrane elevation in presence of sinus septa : anatomic features and surgical management
Maxillary sinus floor elevation via a lateral approach is a predictable technique to increase bone volume of the edentulous posterior maxilla and consequently for dental implants placement. The sinus floor is elevated and it can be augmented with either autologous or xenogeneic bone grafts following an opening bone window created on the facial buccal wall. Maxillary septa are walls of cortical bone within the maxillary sinus. The septa shape has been described as an inverted gothic arch arising from the inferior or lateral walls of the sinus and may even divide the sinus into two or more cavities. Some authors have reported a higher prevalence of septa in atrophic edentulous areas than in nonatrophic ones. Radiographic identification of these structures is important in order to perform the right design of the lateral window during sinus lift. Aim of this investigation is to highlight the correct steps for doing sinus lift surgery in presence of those anatomic variations. Clinicians should always perform clinical and radiographic diagnosis in order to avoid complications related to the sinus lift surgery
Current exposure of Italian women of reproductive age to PFOS and PFOA: a human biomonitoring study
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) concentrations were determined in serum samples collected in 2011-2012 from 549 nulliparous Italian women of reproductive age who resided in six different Italian Regions. Assessment of exposure to perfluorinated compounds was part of a large human biomonitoring study (Project Life Plus "Womenbiopop") that aimed at examining the exposure of women of reproductive age to priority organic pollutants. The median concentrations of PFOS and PFOA were 2.43, and 1.55ngg-1, respectively. Significant differences in the concentrations of both compounds were observed among the six Regions. Women from central Italy had the highest levels of both compounds, followed by women from northern Italy, and southern Italy. No differences in the PFOS concentrations were found between women from urban/industrial areas and women from rural areas, whereas the levels of PFOA were significantly higher in women residing in urban/industrial areas than in women residing in rural areas. Taken together, the observed concentrations confirm that the overall exposure of the Italian population is among the lowest observed in industrialized countries. A downward temporal trend in exposure was observed for both compounds when comparing the results from the present study with those assessed in a study conducted in 2008
Prediction of Distant Recurrence-Free Survival in Resectable Lung Adenocarcinoma.
OBJECTIVES: Optimal procedures for adjuvant treatment and post-surgical surveillance of resected non-small-cell lung cancer remain under discussion. Pathological features are the main determinant of follow-up therapy but have limited ability to identify patients at risk of recurrence. Increasingly, molecular markers are incorporated into clinical decision-making, including measures of tumor growth. The CCP score is a quantitative, molecular measure of proliferation derived from the RNA expression of 31 cell cycle genes and a component of the molecular prognostic score (mPS). The mPS score is a linear combination of CCP score and pathological stage. CCP score and mPS are independent predictors of survival in resected lung adenocarcinoma. MATERIALS AND METHODS: CCP scores were determined by RT-qPCR for 318 patients diagnosed with stage I-II lung adenocarcinoma. Association of mPS and CCP score with distant recurrence and lung-cancer specific survival was assessed in Cox proportional hazards regression models adjusted for age, gender, tumor size, pathological stage and pleural invasion. Distant recurrence-free survival and lung-cancer specific survival by mPS risk group were calculated by Kaplan-Meier survival analysis. RESULTS: CCP scores were obtained for 205 stage I and 84 stage II patients. CCP score and mPS were independent markers of distant recurrence (CCP: HR 1.62, 95%CI 1.15-2.29, p=0.0055; mPS: HR 2.22, 95%CI 1.11-4.44, p=0.023). Patients with low mPS tumors were at significantly reduced risk of distant recurrence (log-rank p=4.2×10-5). Among stage I patients, stratification by mPS identified a patient group with increased risk of distant recurrence (36%, 95%CI 28-46%, log-rank p=0.0011) CONCLUSIONS: The molecular prognostic score stratifies early-stage, resected lung cancer patients for risk of distant recurrence and could be useful to inform treatment and surveillance decisions
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