266 research outputs found

    The Effect of wake Turbulence Intensity on Transition in a Compressor Cascade

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    Direct numerical simulations of separating flow along a section at midspan of a low-pressure V103 compressor cascade with periodically incoming wakes were performed. By varying the strength of the wake, its influence on both boundary layer separation and bypass transition were examined. Due to the presence of small-scale three-dimensional fluctuations in the wakes, the flow along the pressure surface undergoes bypass transition. Only in the weak-wake case, the boundary layer reaches a nearly-separated state between impinging wakes. In all simulations, the flow along the suction surface was found to separate. In the simulation with the strong wakes, separation is intermittently suppressed as the periodically passing wakes managed to trigger turbulent spots upstream of the location of separation. As these turbulent spots convect downstream, they locally suppress separation. © 2014 Springer Science+Business Media Dordrecht

    Assessing internet-based information used to aid patient decision-making about surgery for perianal Crohn's fistula.

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    BACKGROUND: Decision-making in perianal Crohn's fistula (pCD) is preference sensitive. Patients use the internet to access healthcare information. The aim of this study was to assess the online information and patient decision aids relating to surgery for pCD. METHODS: A search of Google™ and the Decision Aids Library Inventory (DALI) was performed using a predefined search strategy. Patient-focussed sources providing information about pCD surgery were included in the analysis. Written health information was assessed using the International Patient Decision Aids Standards (IPDAS) and DISCERN criteria. The readability of the source content was assessed using the Flesch-Kincaid score. RESULTS: Of the 201 sources found, 187 were excluded, leaving 14 sources for analysis. Three sources were dedicated to pCD, and six sources mentioned pCD-specific outcomes. The most common surgical intervention reported was seton insertion (n = 13). The least common surgical intervention reported was proctectomy (n = 1). The mean IPDAS and DISCERN scores were 4.43 ± 1.65 out of 12 (range = 2-8) and 2.93 ± 0.73 out of 5 (range = 1-5), respectively. The mean reading ease was US college standard. CONCLUSIONS: We found no patient decision aids relating to surgery for pCD. The online sources relating to surgery for pCD are few, and their quality is poor, as seen in the low IPDAS and DISCERN scores. Less than half of the sources mentioned pCD-specific outcomes, and three sources were solely dedicated to providing information on pCD. Healthcare professionals should look to create a patient tool to assist decision-making in pCD

    Electrolytic ablation of the rat pancreas: a feasibility trial

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    BACKGROUND: Pancreatic cancer is a biologically aggressive disease with less than 20% of patients suitable for a "curative" surgical resection. This, combined with the poor 5-year survival indicates that effective palliative methods for symptom relief are required. Currently there are no ablative techniques to treat pancreatic cancer in clinical use. Tissue electrolysis is the delivery of a direct current between an anode and cathode to induce localised necrosis. Electrolysis has been shown to be safe and reliable in producing hepatic tissue and tumour ablation in animal models and in a limited number of patients. This study investigates the feasibility of using electrolysis to produce localised pancreatic necrosis in a healthy rat model. METHOD: Ten rats were studied in total. Eight rats were treated with variable "doses" of coulombs, and the systemic and local effects were assessed; 2 rats were used as controls. RESULTS: Seven rats tolerated the procedure well without morbidity or mortality, and one died immediately post procedure. One control rat died on induction of anaesthesia. Serum amylase and glucose were not significantly affected. CONCLUSION: Electrolysis in the rat pancreas produced localised necrosis and appears both safe, and reproducible. This novel technique could offer significant advantages for patients with unresectable pancreatic tumours. The next stage of the study is to assess pancreatic electrolysis in a pig model, prior to human pilot studies

    Phospho-ERK and AKT status, but not KRAS mutation status, are associated with outcomes in rectal cancer treated with chemoradiotherapy

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    <p>Abstract</p> <p>Background</p> <p><it>KRAS </it>mutations may predict poor response to radiotherapy. Downstream events from <it>KRAS</it>, such as activation of <it>BRAF</it>, AKT and ERK, may also confer prognostic information but have not been tested in rectal cancer (RC). Our objective was to explore the relationships of <it>KRAS </it>and <it>BRAF </it>mutation status with p-AKT and p-ERK and outcomes in RC.</p> <p>Methods</p> <p>Pre-radiotherapy RC tumor biopsies were evaluated. <it>KRAS </it>and <it>BRAF </it>mutations were assessed by pyrosequencing; p-AKT and p-ERK expression by immunohistochemistry.</p> <p>Results</p> <p>Of 70 patients, mean age was 58; 36% stage II, 56% stage III, and 9% stage IV. Responses to neoadjuvant chemoradiotherapy: 64% limited, 19% major, and 17% pathologic complete response. 64% were <it>KRAS </it>WT, 95% were <it>BRAF </it>WT. High p-ERK levels were associated with improved OS but not for p-AKT. High levels of p-AKT and p-ERK expression were associated with better responses. <it>KRAS </it>WT correlated with lower p-AKT expression but not p-ERK expression. No differences in OS, residual disease, or tumor downstaging were detected by <it>KRAS </it>status.</p> <p>Conclusions</p> <p><it>KRAS </it>mutation was not associated with lesser response to chemoradiotherapy or worse OS. High p-ERK expression was associated with better OS and response. Higher p-AKT expression was correlated with better response but not OS.</p

    Update of complications and functional outcome of the ileo-pouch anal anastomosis: overview of evidence and meta-analysis of 96 observational studies

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    Item does not contain fulltextOBJECTIVE: The objective of this study is to provide a comprehensive update of the outcome of the ileo-pouch anal anastomosis (IPAA). DATA SOURCES: An extensive search in PubMed, EMBASE, and The Cochrane Library was conducted. STUDY SELECTION AND DATA EXTRACTION: All studies published after 2000 reporting on complications or functional outcome after a primary open IPAA procedure for UC or FAP were selected. Study characteristics, functional outcome, and complications were extracted. DATA SYNTHESIS: A review with similar methodology conducted 10 years earlier was used to evaluate developments in outcome over time. Pooled estimates were compared using a random-effects logistic meta-analyzing technique. Analyses focusing on the effect of time of study conductance, centralization, and variation in surgical techniques were performed. RESULTS: Fifty-three studies including 14,966 patients were included. Pooled rates of pouch failure and pelvic sepsis were 4.3% (95% CI, 3.5-6.3) and 7.5% (95% CI 6.1-9.1), respectively. Compared to studies published before 2000, a reduction of 2.5% was observed in the pouch failure rate (p = 0.0038). Analysis on the effect of the time of study conductance confirmed a decline in pouch failure. Functional outcome remained stable over time, with a 24-h defecation frequency of 5.9 (95% CI, 5.0-6.9). Technical surgery aspects did not have an important effect on outcome. CONCLUSION: This review provides up to date outcome estimates of the IPAA procedure that can be useful as reference values for practice and research. It is also shows a reduction in pouch failure over time.1 juli 201

    Face Liveness Detection Under Bad Illumination Conditions

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    Spoofing face recognition systems with photos or videos of someone else is not difficult. Sometimes, all one needs is to display a picture on a laptop monitor or a printed photograph to the biometric system. In order to detect this kind of spoofs, in this paper we present a solution that works either with printed or LCD displayed photographs, even under bad illumination conditions without extra-devices or user involvement. Tests conducted on large databases show good improvements of classification accuracy as well as true positive and false positive rates compared to the state-of-the-art. © 2011 IEEE.35573560IEEE,IEEE Signal Processing SocietyNixon, K., Aimale, V., Rowe, R., Spoof detection schemes (2008) Handbook of Biometrics, , Springer USTan, X., Li, Y., Liu, J., Jiang, L., Face liveness detection from a single image with sparse low rank bilinear discriminative model (2010) ECCVLi, J., Wang, Y., Tan, T., Jain, A.K., Live face detection based on the analysis of fourier spectra (2004) Biometric Technology for Human Identification, pp. 296-303Pan, G., Wu, Z., Sun, L., (2008) Recent Advances in Face Recognition, Chapter Liveness Detection for Face Recognition, pp. 235-252. , InTechKollreider, K., Fronthaler, H., Bigun, J., Non-intrusive liveness detection by face images (2009) Image Vision Comput., pp. 233-244. , FebruaryParziale, G., Dittmann, J., Tistarelli, M., Analysis and evaluation of alternatives and advanced solutions for system elements (2005) BioSecureSocolinsky, D.A., Selinger, A., Neuheisel, J.D., Face recognition with visible and thermal infrared imagery (2003) CVIU, pp. 72-114. , JulyFladsrud, T., (2005) Face Recognition in A Border Control Environment: Non-zero Effort Attacks ' Effect on False Acceptance Rate, , Master thesis, Gjovik University College, NorwayTeoh, A., Goh, A., Ngo, A., Random multispace quantization as an analytic mechanism for biohashing of biometric and random identity inputs (2006) IEEE TPAMI, pp. 1892-1901Liu, J., Ji, S., Ye, J., (2009) SLEP: Sparse Learning with Eficient Projections, , http://www.public.asu.edu/~jye02/Software/SLEP, Available atZuiderveld, K., Contrast limited adaptive histograph equalization (1994) Graphic Gems, 4, pp. 474-485Georghiades, A.S., Belhumeur, P.N., Kriegman, D.J., From few to many: Illumination cone models for face recognition under variable lighting and pose (2001) IEEE TPAMI, pp. 643-66
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