1,184 research outputs found

    Strengths and Pitfalls of Meta-Analysis Reports in Vesicoureteral Reflux

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    There are many ongoing controversies surrounding vesicoureteral reflux (VUR). These include variable aspects of this common congenital anomaly. Lack of evidence-based recommendations has prolonged the debate. Systematic reviews (SRs) and meta-analysis (MA) are considered high-level evidence. The purpose of this review article is to summarize and critically appraise the available SR/MA pertaining to VUR. We also discuss the strength and pitfalls of SR/MA in general. A thorough literature search identified 9 SRs/MAs relevant to VUR. Both authors critically reviewed these articles for contents and methodological issues. There are many concerns about the quality of the studies included in these SRs. Clinical heterogeneity stemming from different patient selection criteria, interventions, and outcome definitions is a major issue. In spite of major advances in understanding different aspects of VUR in the last few decades, there is a paucity of randomized controlled trials in this field

    Synthesis of neural networks for spatio-temporal spike pattern recognition and processing

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    The advent of large scale neural computational platforms has highlighted the lack of algorithms for synthesis of neural structures to perform predefined cognitive tasks. The Neural Engineering Framework offers one such synthesis, but it is most effective for a spike rate representation of neural information, and it requires a large number of neurons to implement simple functions. We describe a neural network synthesis method that generates synaptic connectivity for neurons which process time-encoded neural signals, and which makes very sparse use of neurons. The method allows the user to specify, arbitrarily, neuronal characteristics such as axonal and dendritic delays, and synaptic transfer functions, and then solves for the optimal input-output relationship using computed dendritic weights. The method may be used for batch or online learning and has an extremely fast optimization process. We demonstrate its use in generating a network to recognize speech which is sparsely encoded as spike times.Comment: In submission to Frontiers in Neuromorphic Engineerin

    Enhanced nasopharyngeal infection and shedding associated with an epidemic lineage of emm3 group A Streptococcus

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    Background: A group A Streptococcus (GAS) lineage of genotype emm3, sequence type 15 (ST15) was associated with a six month upsurge in invasive GAS disease in the UK. The epidemic lineage (Lineage C) had lost two typical emm3 prophages, Φ315.1 and Φ315.2 associated with the superantigen ssa, but gained a different prophage (ΦUK-M3.1) associated with a different superantigen, speC and a DNAse spd1. Methods and Results: The presence of speC and spd1 in Lineage C ST15 strains enhanced both in vitro mitogenic and DNAse activities over non-Lineage C ST15 strains. Invasive disease models in Galleria mellonella and SPEC-sensitive transgenic mice, revealed no difference in overall invasiveness of Lineage C ST15 strains compared to non-Lineage C ST15 strains, consistent with clinical and epidemiological analysis. Lineage C strains did however markedly prolong murine nasal infection with enhanced nasal and airborne shedding compared to non-Lineage C strains. Deletion of speC or spd1 in two Lineage C strains identified a possible role for spd1 in airborne shedding from the murine nasopharynx. Conclusions: Nasopharyngeal infection and shedding of Lineage C strains was enhanced compared to nonLineage C strains and this was, in part, mediated by the gain of the DNase spd1 through prophage acquisition

    Composite nanoclay-hydroxyapatite-polymer fiber scaffolds for bone tissue engineering manufactured using pressurized gyration

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    A novel fabrication of polymer composite fibers using polycaprolactone (PCL), montmorillonite nanoclay (MMT-Clay), and nano-hydroxyapatite-clay (HAP MMT-Clay) is reported for bone tissue engineering applications. Using a pressurized gyration (PG) setup, polycaprolactone (PCL) fibers incorporated with in situ mineralized HAP MMT-Clay and MMT-Clay were investigated. Using the novel fabrication method, we were able to successfully manufacture HAP-nanoclay-PCL fibers. Further, 3D scaffolds made using the prepared fibers were able to enhance bone growth, cell viability, and proliferation. The results demonstrated that the polymer fiber scaffolds are biocompatible, and the cells were able to thrive and differentiate on the fiber scaffolds. A significant increase in cell viability, osteogenic differentiation, ECM formation, and collagen formation was observed with PCL HAP MMT-Clay fibers scaffolds compared to the behaviors in PCL fibers. Further, the intracellular ALP levels increased with PCL HAP MMT-Clay fiber scaffold, indicating enhanced osteogenic differentiation of MSCs. This work shows a promising outlook for the future of manufacturable composite nanoclay polymer fibers incorporated as scaffolds for bone tissue engineering applications

    Correlation of reconstructed scaphoid morphology with clinical outcomes

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    Background: Scaphoid malunion alters the carpal kinematics and impairs clinical outcome because of pain, weakness, restricted range of motion and predisposing the wrist joint to early osteoarthritis. The aim of this study was to evaluate the influence of the scaphoid morphological angles on clinical outcomes in patients with reconstructed scaphoid by non-vascularized bone graft. Methods: Seventeen male patients with the mean age of 31.7±3.7 years and mean non-union time of 31.5±14.7 months were enrolled in this retrospective study. Average follow up was 48.8±9.4 months. At the last follow-up, the patients were evaluated clinically for pain, wrist range of motion, grip strength, and wrist functional status. They were also evaluated radiologically by wrist radiographs and computerized tomography (CT). The overall clinical outcomes were evaluated by the Cooney wrist function score. The morphology of the reconstructed scaphoids was evaluated by the lateral intrascaphoid angle, antroposterior intrascaphoid angle, dorsal cortical angle, measuring the length (mm), and height-to-length ratio on CT scan. The radiological measurements were compared against the overall clinical outcomes. Results: There were 7 excellent, 7 good, 3 fair clinical results. The mean Cooney wrist function score was 83±4. The mean lateral intrascaphoid angle was 34.8±1.4 degrees, mean antroposterior intrascaphoid angle was 33.4±2.2 degrees, mean dorsal cortical angle was 158.3±4.8 degrees, mean scaphoid length was 22.1± 0.7 mm, and mean scaphoid height-to-length ratio was 0.74±0.04. There were no significant statistical correlations between the lateral intrascaphoid angles, antroposterior intrascaphoid angles, dorsal cortical angles, scaphoid lengths and scaphoid height-to-length ratios and Cooney wrist scores in the patients. Conclusion: In the current study, all the patients had some degree of scaphoid malunion; however, the radiological measurements of the reconstructed scaphoids did not correlate with the clinical outcomes. © 2015 BY THE ARCHIVES OF BONE AND JOINT SURGERY

    Interacting spin-2 fields in three dimensions

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    Using the frame formulation of multi-gravity in three dimensions, we show that demanding the presence of secondary constraints which remove the Boulware-Deser ghosts restricts the possible interaction terms of the theory and identifies invertible frame field combinations whose effective metric may consistently couple to matter. The resulting ghost-free theories can be represented by theory graphs which are trees. In the case of three frame fields, we explicitly show that the requirement of positive masses and energies for the bulk spin-2 modes in AdS3_3 is consistent with a positive central charge for the putative dual CFT2_2.Comment: 26 pages, 3 figures, v2: minor changes, matches published versio

    Early Detection of Breast Cancer Using Machine Learning Techniques

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    Cancer is the second cause of death in the world. 8.8 million patients died due to cancer in 2015. Breast cancer is the leading cause of death among women. Several types of research have been done on early detection of breast cancer to start treatment and increase the chance of survival. Most of the studies concentrated on mammogram images. However, mammogram images sometimes have a risk of false detection that may endanger the patient’s health. It is vital to find alternative methods which are easier to implement and work with different data sets, cheaper and safer, that can produce a more reliable prediction. This paper proposes a hybrid model combined of several Machine Learning (ML) algorithms including Support Vector Machine (SVM), Artificial Neural Network (ANN), K-Nearest Neighbor (KNN), Decision Tree (DT) for effective breast cancer detection. This study also discusses the datasets used for breast cancer detection and diagnosis. The proposed model can be used with different data types such as image, blood, etc

    Creep in oak material from the Vasa ship: verification of linear viscoelasticity and identification of stress thresholds

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    Creep deformation is a general problem for large wooden structures, and in particular for shipwrecks in museums. In this study, experimental creep data on the wooden cubic samples from the Vasa ship have been analysed to confirm the linearity of the viscoelastic response in the directions where creep was detectable (T and R directions). Isochronous stress-strain curves were derived for relevant uniaxial compressive stresses within reasonable time spans. These curves and the associated creep compliance values justify that it is reasonable to assume a linear viscoelastic behaviour within the tested ranges, given the high degree of general variability. Furthermore, the creep curves were fitted with a one-dimensional standard linear solid model, and although the rheological parameters show a fair amount of scatter, they are candidates as input parameters in a numerical model to predict creep deformations. The isochronous stress-strain relationships were used to define a creep threshold stress below which only negligible creep is expected. These thresholds ranges were 0.3-0.5 MPa in the R direction and 0.05-0.2 MPa in the T direction
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