28 research outputs found

    Numerical Modeling Of Flow And Sediment Transport Within The Lower Reaches Of The Athabasca River: A Case Study

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    This study investigates flow and sediment transport patterns within the lower reaches of the Athabasca River (~250 km) in Alberta, Canada, which are characterized by complex bathymetry, regions of high tortuosity, and variable discharges and bed slopes. Sediment within this reach is primarily sand and gravel, but there is also a high percentage (\u3e10%) of cohesive clay with unique settling properties. A combination of 1D and 2D regional numerical modeling is used here to predict hydrodynamics of the flow and transport of suspended sediment. Bathymetry measurements were obtained from a combination of high resolution 3D Geoswath and ADCP surveys, and detailed 2D cross-section measurements. The 1D model solves the advection-diffusion equation for the cohesive sediment floc concentrations, and uses an explicit flocculation algorithm to calculate their distribution. Regional and high resolution local 2D numerical simulations are also completed using the Environmental Fluids Dynamics Code (EFDC) for the entire reach and a reach near Steepbank River (\u3c20 km) respectively. The high resolution local model helps in understanding the effects of coarse grid resolution and subsequently bathymetry resolution on the predictions. Validation of the model results is completed using field measurements including water surface elevations collected with Global Positioning System (GPS), water velocities collected using a Gurley current meter, and suspended sediment measurements obtained from the Regional Aquatics Monitoring Program

    Risk Assessment and Ranking through Integration Failure Mode and Effects Analysis and Multiple-Criteria Decision-Making in an Interval Valued Fuzzy Environment: A Case Study in Hydraulic Pump Industry

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    Background and Objective: Nowadays with the increase of global competition, companies apply several scientific methods to identify, assess, and remove potential failures in the production process. In this regard, the present study aimed to identify and analyze the potential failure modes in a hydraulic pump manufacturing company by using a combination of interval valued fuzzy analytic network process (IVF-ANP), interval valued fuzzy failure mode effect and analysts (IVF-FMEA), and interval valued fuzzy TOPSIS (IVF-TOPSIS). Materials and Methods: For the purposes of the study, first, the potential failure modes of the production process were identified using the opinion of experts. Then, the failure modes were prioritized based on the proposed method. The proposed approach applied the IVF-ANP to determine the weight of each risk assessment factor and a combination of IVF-FMEA and IVF-TOPSIS to rank the potential failure modes. Results: In total, 30 failure modes were identified in the present study. The highest-ranking failure mode was inappropriate feed rate with a relative closeness of 0.83. On the other hand, the lowest-ranking failure mode was the large size of the bush with a relative closeness of 0.015. Conclusion: The results showed that the proposed approach is applicable for the assessment and ranking of failure modes. In addition, consideration of some issues like the cost, interdependence of risk assessment factors, and also modeling the method under the condition of interval valued fuzzy uncertainty, affected the final ranking of failure modes

    Treatment of full thickness cartilage defects in human knees with Autologous Chondrocyte Transplantation*

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    Background: Although a variety of strategies have been employed for managing articular cartilage defects in the knee, overall outcomes have not been satisfactory. An alternative option may be autologous chondrocyte transplantation (ACT). However, as this method is still under investigation, here we assessed the efficacy of ACT for human knee defect cartilage repair. Methods: In a randomized clinical trial study, eleven patients (mean age 31.09 years) were enrolled in the study with full thickness cartilage defects in the knee. Arthroscopically, healthy cartilage was obtained, chondrocytes expanded for 2-3 weeks and ACT performed. Clinical status was evaluated before ACT, 6 and 12 months after ACT using the Brittberg-Peterson functional assessment and modified Cincinnati rating score. Magnetic resonance imaging (MRI) findings were evaluated based on the scoring systems used by Sally Roberts and by Henderson. Results: Modified Cincinnati rating indicated significant improvement of clinical score before ACT compared to 6 (p = 0.000) and 12 (p = 0.000) months after ACT (from 2.73 before ACT to 7.27, 8.36 and 9.5 at 6, 12, and 48 months after ACT, respectively). Brittberg-Peterson functional assessment indicated a decline from 79.27 to 25.82 and 19.27 at 6 and 12 months post ACT. Further, statistical test demonstrated significant differences 6, 12 and 48 months post ACT (p = 0.007). Evaluation of MRI revealed a score of 6.5 for Henderson criteria and a score of 2.5 for Robert criteria. Conclusions: Our study demonstrated that ACT of the knee provides an excellent treatment for full thickness cartilage defects with outstanding clinical and radiological outcomes

    Resveratrol suppresses interleukin-1beta-induced inflammatory signaling and apoptosis in human articular chondrocytes: potential for use as a novel nutraceutical for the treatment of osteoarthritis

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    Osteoarthritis is an inflammatory disease of load-bearing synovial joints that is currently treated with drugs that exhibit numerous side effects and are only temporarily effective on pain, the main symptom of the disease. Consequently, there is an acute need for novel, safe and more effective chemotherapeutic agents for the treatment of osteoarthritis and related arthritic diseases. Resveratrol is a phytoalexin stilbene produced naturally by plants including red grapes, peanuts and various berries. Recent research in various cell models has demonstrated that resveratrol is safe and has potent anti-inflammatory properties. However, its potential for treating arthritic conditions has not been explored. In this study we provide experimental evidence that resveratrol inhibits the expression of VEGF, MMP-3, MMP-9 and COX-2 in human articular chondrocytes stimulated with the pro-inflammatory cytokine IL-1beta. Since these gene products are regulated by the transcription factor NF-kappaB, we investigated the effects of resveratrol on IL-1beta-induced NF-kappaB signaling pathway. Resveratrol, like N-Ac-Leu-Leu-norleucinal (ALLN) suppressed IL-1beta-induced proteasome function and the degradation of IkappaBalpha (an inhibitor of NF-kappaB) without affecting IkappaBalpha kinase activation, IkappaBalpha-phosphorylation or IkappaBalpha-ubiquitination which suppressed nuclear translocation of the p65 subunit of NF-kappaB and its phosphorylation. Furthermore, we observed that resveratrol as well as ALLN inhibited IL-1beta-induced apoptosis, caspase-3 activation and PARP cleavage in human articular chondrocytes. In summary, our results suggest that resveratrol suppresses apoptosis and inflammatory signaling through its actions on the NF-kappaB pathway in human chondrocytes. We propose that resveratrol should be explored further for the prophylactic treatment of osteoarthritis in humans and companion animals
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