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Karlsruhe, Germany

Brown B.,University of California at San Diego | Brown B.,Excellence Center | Reeves S.,University of Nottingham | Sherwood S.,University of Glasgow
Conference on Human Factors in Computing Systems - Proceedings | Year: 2011

Field trials of experimental systems 'in the wild' have developed into a standard method within HCI - testing new systems with groups of users in relatively unconstrained settings outside of the laboratory. In this paper we discuss methodological challenges in running user trials. Using a 'trial of trials' we examined the practices of investigators and participants - documenting 'demand characteristics', where users adjust their behaviour to fit the expectations of those running the trial, the interdependence of how trials are run and the result they produce, and how trial results can be dependent on the insights of a subset of trial participants. We develop three strategies that researchers can use to leverage these challenges to run better trials. Copyright 2011 ACM. Source

Bisciotti G.N.,Excellence Center | Bisciotti G.N.,Sportiva | Bisciotti G.N.,Kinemove Rehabilitation Centers | Eirale C.,Excellence Center | Lello P.P.,Kinemove Rehabilitation Centers
Minerva Ortopedica e Traumatologica | Year: 2010

The bone bruising (BB) is a pathology determined from a traumatic compressive force in bone structure. Its onset can be attributed both to a single traumatic event of high intensity, that to a repeated microtrauma. Contrary the syndrome of bone marrow edema (BME), does not have a traumatic etiology and is more observable at the hip and knee joints and into the proximal femur. The important increase in the use of MRI in recent years has raised the questions concerning these two diseases, which have been largely underestimated in the past because not detectable by conventional radiological technique. The present paper describes both the BB and bone marrow edema taking in account their different impact on the joints and their resolving times. It is also discussed their treatment through the use of high intensity magnetic fields. Source

Bergstrand A.,Chalmers University of Technology | Bergstrand A.,Excellence Center | Uppstrom S.,Chalmers University of Technology | Larsson A.,Chalmers University of Technology | Larsson A.,Excellence Center
International Journal of Polymer Science | Year: 2014

Poly(3-hydroxybutyrate) (PHB) is a polyester which shows excellent biocompatibility and a PHB material is therefore considered suitable for many biomedical applications. A highly porous PHB material may be designed to facilitate the transport of small molecules and body fluids or serve as a biocompatible temporary barrier. In this study, PHB films with varying degree of porosity and pore interconnectivity were made by solvent casting using water-in-oil emulsion templates of varying composition. The morphology was characterized by SEM and the water permeability of the films was determined. The results show that an increased water content of the template emulsion resulted in a film with increased porosity. A fine tuning of the film morphology of the casted films was achieved by varying the salt content of the water phase of the template emulsion. The porosity of these films was roughly the same but the water permeability varied between 2 3 · 10 - 13 and 1486 · 10 - 13 m 2 / s. It was concluded that the major determinant of the water permeability through these films is the pore interconnectivity. Furthermore, we report on the formation and water permeability of bilayer PHB films consisting of a porous layer combined with a dense backing layer. © 2014 Anna Bergstrand et al. Source

News Article
Site: http://www.nanotech-now.com/

Home > Press > Flexoelectricity is more than Moore Abstract: The information revolution is synonymous with the traditional quest to pack more chips and increase computing power. This quest is embodied by the famous "Moore's law", which predicts that the number of transistors per chip doubles every couple of years and has held true for a remarkably long time. However, as Moore´s law approaches its limit, a parallel quest is becoming increasingly important. This latter quest is nick-named "more than Moore", and it aims to add new functionalities (not just transistors) within each chip by integrating smart materials on top of the ubiquitous and still indispensable silicon base. Among these so-called smart materials piezoelectrics stand out for their ability to convert a mechanical deformation into a voltage (which can be used to harvest energy to feed the battery) or, conversely, generate a deformation when a voltage is applied to them (which can be used, for example, in piezoelectric fans for cooling down the circuit). However, the integration of piezoelectricity with silicon technology is extremely challenging. The range of piezoelectric materials to choose from is limited, and the best piezo electrics are all lead based ferroelectric materials, and their toxicity poses serious concerns. Moreover, their piezoelectric properties are strongly temperature-dependent, making them difficult to implement in the hot environment of a typical computer processor, whose junction temperature can reach up to 150 Celsius. There exists, however, another form of electromechanical coupling that allows a material to polarize in response to a mechanical bending moment, and, conversely, to bend in response to an electric field. This property is called "flexoelectricity", and though it has been known for nearly half a century, it has been largely ignored because it is a relatively weak effect of little practical significance at the macroscale. However, at the nanoscale flexoelectricity can be as big as or bigger than piezoelectricity; this is easy to understand if we consider that bending something thick is very difficult, but bending something thin is very easy. In addition, flexoelectricity offers many desirable properties: it is a universal property of all dielectrics, meaning that one needs not use toxic lead-based materials, and flexoelectricity is more linear and temperature-independent than the piezoelectricity of a ferroelectric. Researchers from the Catalan Institute of Nanoscience and Nanotechnology (ICN2), a research center awarded as Severo Ochoa Excellence Center and placed in the Campus of the Universitat Autònoma de Barcelona (UAB), in collaboration with the University of Cornell (USA) and the University of Twente (Netherlands), have now managed to produce the world's first integrated flexoelectric microelectromechanical system (MEMS) on silicon. They have found that, at the nanoscale, the desirable attributes of flexoelectricity are maintained, while the figure of merit (bending curvature divided by electric field applied) of their first prototype is already comparable to that of the state of the art piezoelectric bimorph cantilevers. Additionally, the universality of flexoelectricity implies that all high-k dielectric materials used currently in transistor technology should also be flexoelectric, thus providing an elegant route to integrating "intelligent" electromechanical functionalities within already existing transistor technology. The results are published today by Nature Nanotechnology. ### The project, led by Dr Umesh Bhaskar and ICREA Professor Gustau Catalan, from the ICN2 Oxide Nanoelectronics Group, was funded by an European Research Council (ERC) Consolidator Grant and a Spanish Project from Plan Nacional de Excelencia Investigadora, as well as by national grants for the US and Dutch teams. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Kisters K.,Excellence Center | Wessels F.,Excellence Center | Nguyen M.Q.,Ruhr University Bochum | Mitchell A.,Ruhr University Bochum | And 9 more authors.
Trace Elements and Electrolytes | Year: 2012

A magnesium deficiency plays a pathogenetic role in the development of primary hypertension. We have measured plasma and intracellular Mg++ levels in erythrocytes of 18 untreated borderline hypertensive patients, and in 35 untreated normotensive healthy subjects as controls. In patients intracellular Mg++ content was significantly lower (1.61 ± 0.09 mmol/l ± SD), than in controls (1.84 ± 0.14 mmol/l, p < 0.05), After 12 - 15 weeks of an oral supplementation with 240 - 480 mg Mg ++/day, the erythrocyte Mg++ content had increased significantly in the borderline hypertensive group (1.78 ± 0.11 mmol/l, p < 0.05). There was no significant difference between the normotensive and borderline hypertensive group in plasma Mg++ concentrations (0.87 ± 0.13 vs. 0.83 ± 0.17 mmol/l). Systolic and diastolic blood pressure values of the borderline hypertensive group also normalized after oral Mg++ administration (before therapy: 147.6 ± 8.5/87.2 ± 4.4 mmHg, after therapy: 137.2 ± 4.6/83.8 ± 3.4 mmHg, p < 0.05). We conclude that Mg++ deficient borderline hypertensives can benefit from magnesium supplementation with regard to high blood pressure and quality of life. ©2012 Dustri-Verlag Dr. K. Feistle. Source

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