Technical validation of low-cost videoconferencing systems applied in orthopaedic teleconsulting services.

Investigation on the applicability of low-cost videoconferencing (VC) for health care services is becoming a real need. Reduced resources drive the administrators to evaluate inexpensive solutions for telemedicine. Considering this scenario, this work is a preliminary step to validate, from a technical point of view, if low-cost VC systems could be suitable for orthopaedic teleconsulting services. For this purpose, four different videoconferencing systems were tested. Each VC system was composed of a computer and a VC device installed in. VC devices were chosen among the most popular and distributed products (made by Intel, PictureTel and Aethra). The Telemedicine Benchmark, a specific tool defined by the authors, was applied to measure the overall systems performances in terms of time delays during basic rate ISDN connections (128 Kbit/s). Results showed that it is possible to apply low-cost videoconferencing systems for orthopaedic teleconsulting services. Most of the systems provided acceptable performance for medical image visualization and real time joint working. Further developments are recommendable to enhance the VC software tools capabilities and to improve software-user interface. reserved.     

Parametric free-form shape design with PDE models and reduced basis method

We present a coupling of the reduced basis methods and free-form deformations for shape optimization and design of systems modelled by elliptic PDEs. The free-form deformations give a parameterization of the shape that is independent of the mesh, the initial geometry, and the underlying PDE model. The resulting parametric PDEs are solved by reduced basis methods. An important role in our implementation is played by the recently proposed empirical interpolation method, which allows approximating the non-affinely parameterized deformations with affinely parameterized ones. These ingredients together give rise to an efficient online computational procedure for a repeated evaluation design environment like the one for shape optimization. The proposed approach is demonstrated on an airfoil inverse design problem.     

A usability comparison of PDA-based quizzes and paper-and-pencil quizzes

In the last few years, schools and universities have incorporated personal digital assistants (PDAs) into their teaching curricula in an attempt to enhance students’ learning experience and reduce instructors’ workload. One of the most common uses of PDAs in the classroom is as a test administrator. This study compared the usability effectiveness, efficiency, and satisfaction of a PDA-based quiz application to that of standard paper-and-pencil quizzes in a university course. Effectiveness was measured as students’ quiz scores and through a mental workload questionnaire; efficiency was the time it took students to complete each quiz; and satisfaction was evaluated using a subjective user satisfaction questionnaire. The study showed the PDA-based quiz to be more efficient, that is, students completed it in less time than they needed to complete the paper-and-pencil quiz. No differences in effectiveness and satisfaction were found between the two quiz types. Computer anxiety was not affected by the quiz type. For these reasons, as well as other advantages to both students (e.g., real-time scoring) and teachers (e.g., less time spent on grading), PDAs are an attractive test administration option for schools and universities.     

图解静力学:一种实现强结构的操作方法

图解静力学是一种基于矢量的构建平衡方法,它使得交汇了结构思维和建筑概念的设计方法成为可能.该方法以参数化和拓扑操作为基础,允许对空间中的拉力和压力进行可控的分布,进而塑造建筑结构.本文讨论了图解静力学的基本框架,并举例说明了其在一些项目中的设计方法.     

Electrospinning silica/polyvinylpyrrolidone composite nanofibers

Small diameter nanofibers of silica and silica/polymer are produced by electrospinning silica/polyvinylpyrrolidone (SiO₂/PVP) mixtures composed of silica nanoparticles dispersed in polyvinylpyrrolidone solutions. By controlling various parameters, 380 ± 100 nm diameter composite nanofibers were obtained with a high silica concentration (57.14%). When the polymer concentration was low, “beads‐on‐a‐string” morphology resulted. Nanofiber morphology was affected by applied voltage and relative humidity. Tip‐to‐collector distance did not affect the nanofiber diameter or morphology, but it did affect the area and thickness of the mat. Heat treatment of the composite nanofibers at 200°C crosslinked the polymer yielding solvent‐resistant composite nanofibers, while heating at 465°C calcined and selectively removed the polymer from the composite. Crosslinking did not change the nanofiber diameter, while calcined nanofibers decreased in diameter (300 ± 90 nm) and increased in surface area to volume ratio. Nanofibers were characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40966.     

Microhardness evaluations of the bone growing into porous implants

Small cylinders of a new composite porous material consisting of a dense alumina core coated with two layers of beads of the same material, bonded to each other and to the underlying surface by a high-temperature melting glass have been implanted in the proximal femurs of rabbits. The explants were carried out 1, 4, 6, 8, and 18 weeks after surgery. The bone fragment containing the implant was embedded in methyl methacrylate without performing decalcification, and morphological observations were carried out. These showed that four weeks after surgery it is already possible to observe the development of bone spicules in the implant porosities. Along with these studies, microhardness measurements were carried out by using a microhardness tester connected to an image analyser. The mineralized tissue in close contact with the implant showed, one month after surgery, a compression strength similar to that of healthy bone.     

Photoluminescence investigations on alumina ceramic bearing couples tested under different angles of inclination in a Hip joint simulator

Aseptic loosening due to wear and dislocation of the implant represents the main complication after total hip arthroplasty. To gain more insight into the influence of the implant position on wear, commercial alumina couplings have been tested in a hip joint simulator under three different angles of cup inclination (23°, 45°, 63°) with respect to a horizontal plane. The planned length of the test was ten million cycles. However, the test was stopped at 5.5 million cycles due to the fracture of one of the femoral heads, tested with at angle of 63°. The residual stress state in the worn acetabular cups and in the fractured femoral head were evaluated by the frequency shift and broadening of the R₁ and R₂ fluorescence bands due to the Cr³⁺ ions naturally present in alumina ceramics as trace impurities. The gravimetric measurements did not show significant differences among the three different inclinations tested, in agreement with previous simulator studies, but in disagreement with in vivo findings. The fluorescence measurements allowed to affirm that an angle of 63° represents a worsened mechanical condition for the prosthetic component, with a consequently higher probability of fracture and/or damage potentially conducive to massive wear. In the light of the fluorescence results, it did not appear surprising that the femoral head that fractured was the one being tested at 63°.     

Fatigue strength of PMMA bone cement mixed with gentamicin and barium sulphate vs pure PMMA

Barium sulphate is added to polymethylmethacrylate (PMMA) bone cement as a radiopacifier. Gentamicin is an antibiotic added to bone cement to treat or prevent infection in arthroplasty. This study investigated the combined effect of barium sulphate and gentamicin sulphate on the fatigue strength of PMMA bone cement. Three different formulations were studied: pure PMMA, PMMA with barium sulphate added and PMMA with barium sulphate and gentamicin sulphate added. Before testing all specimens were stored in water at 37 degrees C for at least 15 days to season the PMMA and to elute the antibiotic. Fatigue tests were performed following a previously validated procedure. The slope part of the W?hler diagram was obtained and a rough endurance limit was estimated for all three formulations. The experimental data showed that the addition of barium sulphate to PMMA bone cement affected the fatigue strength of the material, whereas addition of gentamicin sulphate to the radiopaque PMMA had no effect on the fatigue properties of the bone cement. While PMMA with barium sulphate added was confirmed to have a reduced fatigue strength when compared with plain PMMA, no detrimental effect was found for the addition of gentamicin sulphate to radiopaque PMMA.     

Impact of work on women at midlife.

Examined the impact of employment status on the self-esteem, psychological well-being, and physical health of 389 middle-aged (40–59 yrs old) women (206 employed outside the home and 183 homemakers). Ss completed a number of scales of psychological well-being (including the Rosenberg Self-Esteem Scale and the Lack of Depression Scale) from the national survey, The Survey of Modern Living, conducted in 1976. Results indicate that working Ss at midlife had higher self-esteem and less psychological anxiety than homemakers. Working Ss also reported being in better physical health than homemakers. Findings suggest that work may act as a stabilizing force for women during critical periods throughout the life cycle. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structured flowcharts for multiprocessing

We present a flowchart language for parallel processing: in addition to the “standard” components, our flowcharts contain fork, join and synchronizing nodes. Extending the work of Mills, we suggest restrictions on controlling computation flow and show that any proper program can be algorithmically transformed to an equivalent structured program.