528 research outputs found
The reliability of national videos related to the kidney stones on YouTube
Objective: Kidney stones are one of the most common disorders of the urinary tract. With increasing awareness, a larger proportion of patients are seeking medical knowledge from the Internet. In present study, the features, reliability and efficacy of videos on YouTube related to the treatment of kidney stones were evaluated. Material and methods: In December 2014, YouTube was searched using keywords “nephrolithiasis”; “renal calculi”; “renal stones”; and “kidney stones” for videos uploaded containing relevant information about the disease. Only videos in Turkish were included in the study. Two physician viewers watched each video and classified them as useful, partially useful and useless according to European Association of Urology (EAU) Guidelines. The source, length, number of views, number of favourable opinions, and days since uploaded date of the all videos were evaluated. Results: A total of 600 videos were analysed The median length of videos was 6.7±10.4 (median: 3, IQR: 0.03-58) minutes . Each video was viewed at an average of 2368 (min: 11, max: 97133) times. Most of the videos (32.8%) were created by academicians and physicians. Nearly half (47.4%) of the videos were uploaded in 2014. The majority of the videos (62.5%) contained information for treatment. Percutaneous nephrolithotomy and ureterorenoscopy were the most common treatment modalities (32.8% and 28.0%, respectively) in these videos. A statistically significant difference was not detected between view numbers and source of videos (p=0.87). However, there was a statistically significant difference between usefulness to the viewers and source of videos. Hospital -based videos were detected to be more useful (p=0.000). Conclusion: As a result, videos that would be prepared in internet environment by professional individuals or organizations in a way which would attract attention and be easily comprehended by the public could contribute to the knowledge and education of our society about the stone disease which is commonly seen in our country. © 2016 by Turkish Association of Urology
Synthesis of diamondlike carbon films with superlow friction and wear properties
In this study, the authors introduce a new diamondlike carbon (DLC) film providing a friction coefficient of 0.001 and wear rates of 10{sup {minus}9} to 10{sup {minus}10} mm{sup 3}/N.m in inert-gas environments (e.g., dry nitrogen and argon). The film was grown on steel and sapphire substrates in a plasma enhanced chemical vapor deposition system that uses using a hydrogen-rich plasma. Employing a combination of surface and structure analytical techniques, they explored the structural chemistry of the resultant DLC films and correlated these findings with the friction and wear mechanisms of the films. The results of tribological tests under a 10-N load (creating initial peak Hertz pressures of 1 and 2.2 GPa on steel and sapphire test pairs, respectively) and at 0.2 to 0.5 m/s sliding velocities indicated that a close correlation exists between the friction and wear coefficients of DLC films and the source gas chemistry. Specifically, films grown in source gases with higher hydrogen-to-carbon ratios had the lowest fiction coefficients and the highest wear resistance. The lowest friction coefficient (0.001) was achieved with a film on sapphire substrates produced in a gas discharge plasma consisting of 25% methane and 75% hydrogen
What has finite element analysis taught us about diabetic foot disease and its management?:a systematic review
Over the past two decades finite element (FE) analysis has become a popular tool for researchers seeking to simulate the biomechanics of the healthy and diabetic foot. The primary aims of these simulations have been to improve our understanding of the foot's complicated mechanical loading in health and disease and to inform interventions designed to prevent plantar ulceration, a major complication of diabetes. This article provides a systematic review and summary of the findings from FE analysis-based computational simulations of the diabetic foot.A systematic literature search was carried out and 31 relevant articles were identified covering three primary themes: methodological aspects relevant to modelling the diabetic foot; investigations of the pathomechanics of the diabetic foot; and simulation-based design of interventions to reduce ulceration risk.Methodological studies illustrated appropriate use of FE analysis for simulation of foot mechanics, incorporating nonlinear tissue mechanics, contact and rigid body movements. FE studies of pathomechanics have provided estimates of internal soft tissue stresses, and suggest that such stresses may often be considerably larger than those measured at the plantar surface and are proportionally greater in the diabetic foot compared to controls. FE analysis allowed evaluation of insole performance and development of new insole designs, footwear and corrective surgery to effectively provide intervention strategies. The technique also presents the opportunity to simulate the effect of changes associated with the diabetic foot on non-mechanical factors such as blood supply to local tissues.While significant advancement in diabetic foot research has been made possible by the use of FE analysis, translational utility of this powerful tool for routine clinical care at the patient level requires adoption of cost-effective (both in terms of labour and computation) and reliable approaches with clear clinical validity for decision making
Preliminary Results on Evaluation of Chickpea, Cicer arietinum, Genotypes for Resistance to the Pulse Beetle, Callosobruchus maculatus
The chickpea, Cicer arietinum L. (Fabales: Fabaceae), seeds are vulnerable, both in the field and in storage, to attack by seed-beetles. Beetles of the genus Callosobruchus are major storage pests of chickpea crops and cause considerable economic losses. In the present study, a total of 11 chickpea genotypes including five ‘kabuli’ (Mexican white, Diyar, CA 2969, ILC 8617 and ACC 245) and six ‘desi’ chickpeas (ICC 1069, ICC 12422, ICC 14336, ICC 4957, ICC 4969 and ICC 7509) were evaluated for resistance to the pulse beetle Callosobruchus maculatus F. (Coleoptera: Bruchidae). Resistance was evaluated by measuring percent damage to seeds. Damage to seeds by C. maculatus was manifested by the round exit holes with the ‘flap’ of seed coat made by emerging adults. Of the 11 genotypes tested, only one (ICC 4969) exhibited a complete resistance to C. maculatus in both free-choice and no-choice tests; no seed damage was found over the test period. In general, the ‘desi’ chickpeas were more resistant to C. maculatus than the ‘kabuli’ chickpeas. Among the tested chickpea genotypes, only ICC 4969 can be used as a source of C. maculatus resistance in breeding programmes that could then be grown in organic cultivation free from pesticides
Tribological Behavior of Near-Frictionless Carbon Coatings in High- and Low- Sulfur Diesel Fuels
The sulfur content in diesel fuel has a significant effect on diesel engine emissions, which are currently subject to environmental regulations. It has been observed that engine particulate and gaseous emissions are directly proportional to fuel sulfur content. With the introduction of low-sulfur fuels, significant reductions in emissions are expected. The process of sulfur reduction in petroleum-based diesel fuels also reduces the lubricity of the fuel, resulting in premature failure of fuel injectors. Thus, another means of preventing injector failures is needed for engines operating with low-sulfur diesel fuels. In this study, the authors evaluated a near-frictionless carbon (NFC) coating (developed at Argonne National Laboratory) as a possible solution to the problems associated with fuel injector failures in low-lubricity fuels. Tribological tests were conducted with NFC-coated and uncoated H13 and 52100 steels lubricated with high- and low- sulfur diesel fuels in a high-frequency reciprocating test machine. The test results showed that the NFC coatings reduced wear rates by a factor of 10 over those of uncoated steel surfaces. In low-sulfur diesel fuel, the reduction in wear rate was even greater (i.e., by a factor of 12 compared to that of uncoated test pairs), indicating that the NFC coating holds promise as a potential solution to wear problems associated with the use of low-lubricity diesel fuels
Chondrocyte Deformations as a Function of Tibiofemoral Joint Loading Predicted by a Generalized High-Throughput Pipeline of Multi-Scale Simulations
Cells of the musculoskeletal system are known to respond to mechanical loading and chondrocytes within the cartilage are not an exception. However, understanding how joint level loads relate to cell level deformations, e.g. in the cartilage, is not a straightforward task. In this study, a multi-scale analysis pipeline was implemented to post-process the results of a macro-scale finite element (FE) tibiofemoral joint model to provide joint mechanics based displacement boundary conditions to micro-scale cellular FE models of the cartilage, for the purpose of characterizing chondrocyte deformations in relation to tibiofemoral joint loading. It was possible to identify the load distribution within the knee among its tissue structures and ultimately within the cartilage among its extracellular matrix, pericellular environment and resident chondrocytes. Various cellular deformation metrics (aspect ratio change, volumetric strain, cellular effective strain and maximum shear strain) were calculated. To illustrate further utility of this multi-scale modeling pipeline, two micro-scale cartilage constructs were considered: an idealized single cell at the centroid of a 100×100×100 μm block commonly used in past research studies, and an anatomically based (11 cell model of the same volume) representation of the middle zone of tibiofemoral cartilage. In both cases, chondrocytes experienced amplified deformations compared to those at the macro-scale, predicted by simulating one body weight compressive loading on the tibiofemoral joint. In the 11 cell case, all cells experienced less deformation than the single cell case, and also exhibited a larger variance in deformation compared to other cells residing in the same block. The coupling method proved to be highly scalable due to micro-scale model independence that allowed for exploitation of distributed memory computing architecture. The method’s generalized nature also allows for substitution of any macro-scale and/or micro-scale model providing application for other multi-scale continuum mechanics problems
Reproducibility in modeling and simulation of the knee:Academic, industry, and regulatory perspectives
Stakeholders in the modeling and simulation (M&S) community organized a workshop at the 2019 Annual Meeting of the Orthopaedic Research Society (ORS) entitled “Reproducibility in Modeling and Simulation of the Knee: Academic, Industry, and Regulatory Perspectives.” The goal was to discuss efforts among these stakeholders to address irreproducibility in M&S focusing on the knee joint. An academic representative from a leading orthopedic hospital in the United States described a multi-institutional, open effort funded by the National Institutes of Health to assess model reproducibility in computational knee biomechanics. A regulatory representative from the United States Food and Drug Administration indicated the necessity of standards for reproducibility to increase utility of M&S in the regulatory setting. An industry representative from a major orthopedic implant company emphasized improving reproducibility by addressing indeterminacy in personalized modeling through sensitivity analyses, thereby enhancing preclinical evaluation of joint replacement technology. Thought leaders in the M&S community stressed the importance of data sharing to minimize duplication of efforts. A survey comprised 103 attendees revealed strong support for the workshop and for increasing emphasis on computational modeling at future ORS meetings. Nearly all survey respondents (97%) considered reproducibility to be an important issue. Almost half of respondents (45%) tried and failed to reproduce the work of others. Two-thirds of respondents (67%) declared that individual laboratories are most responsible for ensuring reproducible research whereas 44% thought that journals are most responsible. Thought leaders and survey respondents emphasized that computational models must be reproducible and credible to advance knee M&S.</p
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Synergistic Effects of Silver Films and Synthetic Lubricants on Boundary-Lubrication Behavior of Ceramics
In a study seeking to achieve low friction and low wear on ceramic materials, we investigated a new lubrication concept that explores the synergistic effect of a silver film and a recently developed synthetic oil on the boundary lubrication behavior of silicon nitride (Si{sub 3}N{sub 4}) ceramics. Friction and wear tests were performed on a wear test machine at temperatures up to 380{degree}C. Under the test conditions explored, we found that the friction coefficients of Si{sub 3}N{sub 4}/Si{sub 3}N{sub 4} test pairs during oil-lubricated sliding tests ranged from 0.1 to 0.35, and the average wear rates of ceramic pins were between 3 {times} 10{sup {minus}7} and 10{sup {minus}6} mm{sup 3} N{sup {minus}1} m{sup {minus}1}, depending on test temperature. Concurrent use of lubricant oil with a silver film had a synergistic effect on both friction and wear. When silver films are used at oil-lubricated sliding interfaces, wear rates of both pins and flats were reduced to unmeasurable levels and the friction coefficients were reduced by factors of two to ten below those of the test pairs without silver films. Beneficial synergistic effects of silver films and synthetic oil on the boundary-lubrication behavior of ceramics were more pronounced at elevated test temperatures than at room temperature
The Potential Involvement of E-cadherin and β-catenins in Meningioma
To investigate the potential involvements of E-cadherin and β-catenin in meningioma.Immunohistochemistry staining was performed on samples from patients with meningioma. The results were graded according to the positive ratio and intensity of tissue immunoreactivity. The expression of E-cadherin and β-catenin in meningioma was analyzed by its relationship with WHO2007 grading, invasion, peritumoral edema and postoperative recurrence.The positive rates of E-cadherin in meningioma WHO I, II, III were 92.69%, 33.33% and 0, respectively, (P<0.05); while the positive rates of β-catenin in meningioma WHO I, II, III were 82.93%, 33.33% and 20.00%, respectively, (P<0.05). The positive rate of E-cadherin in meningioma without invasion (94.12%) was higher than that with invasion (46.67%) (P<0.05). The difference in the positive rate of β-catenin between meningioma without invasion (88.24%) and meningioma with invasion (33.33%, P<0.05) was also statically significant. The positive rates of E-cadherin in meningioma with peritumoral edema 0, 1, 2, 3 were 93.75%, 85.71%, 60.00% and 0 respectively, (P<0.05); the positive rates of β-catenin in meningioma with peritumoral edema 0, 1, 2, 3 were 87.50%, 85.71%, 30.00% and 0 respectively, (P<0.01). The positive rates of E- cadherin in meningioma with postoperative recurrence were 33.33%, and the positive rate with postoperative non-recurrence was 90.00% (P<0.01). The positive rates of β-catenin in meningioma with postoperative recurrence and non-recurrence were 11.11%, 85.00%, respectively (P<0.01).The expression levels of E- cadherin and β-catenin correlated closely to the WHO 2007 grading criteria for meningioma. In atypical or malignant meningioma, the expression levels of E-cadherin and β-catenin were significantly lower. The expression levels of E- cadherin and β-catenin were also closely correlated with the invasion status of meningioma, the size of the peritumoral edema and the recurrent probabilities of the meningioma, all in an inverse correlationship. Taken together, the present study provided novel molecular targets in clinical treatments to meningioma
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