6,290 research outputs found

    Moving on from e-Learning: Searching for disruptive pedagogies

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    The presentation will explore the context of using ICTs in educational contexts and suggest what elements might be explored for best matches between technology use and its impact. It examines some of the ways in which e-learning has failed to live up to its early promise and explores how this situation might be remedied. Two of the main challenges for the future of e-learning are explored: the ever shifting nature of the e-landscape characterised by its rapidly changing technologies, software and marketing mechanisms; and the difficulty of helping teachers find ways to exploit the capacities offered by these ‘disruptive technologies’ (Christensen, 1997) as they continue to bring about change. It is argued that if our investment in e-learning is to be recouped then what is needed is a paradigm shift to the employment of ‘disruptive pedagogies’. This would involve the use of teaching strategies that exploit the currently underused capacities of technology options in such a way as to enable student engagement, motivation and higher order thinking.Dr John G Hedberg is Millennium Innovations Chair in ICT and Education, and Director of the Macquarie ICT Innovations Centre at Macquarie University, Sydney, Australia. Macquarie ICT Innovations Centre, is a learning partnership with the NSW Department of Education and Training to develop innovative programs in technology enhanced learning for students and teachers. He has been Professor of Learning Sciences and Technologies at Nanyang Technological University in Singapore where he directed several research projects exploring the role of technologies in engaging students in Mathematics, Science, History and Geography classrooms. He is known for the constructivist learning environments he has designed culminating in a British Academy award for an interactive theatre CD-ROM entitled StageStruck. He has wide experience in the design of open and distance learning programs delivered on-line and through CD-ROM. He has published on navigation, cognition and multimodality, design and evaluation in interactive multimedia, the most recent book is Evaluating interactive learning systems with Thomas Reeves has been recently published by Educational Technology publications, He is also the Editor-in-chief of Educational Media International.published_or_final_versionCentre for Information Technology in Education, University of Hong Kon

    Small molecule inhibition of protein depalmitoylation as a new approach towards downregulation of oncogenic Ras signalling

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    AbstractThe H- and N-Ras GTPases are prominent examples of proteins, whose localizations and signalling capacities are regulated by reversible palmitoylations and depalmitoylations. Recently, the novel small molecule inhibitor palmostatin B has been described to inhibit Ras depalmitoylation and to revert the phenotype of oncogenic HRasG12V transformed cells. This demonstrates that palmostatin B is a tool to investigate the biochemical effects of the inhibition of cellular Ras depalmitoylation on Ras signalling, which is relevant for oncology. Furthermore, it is to be expected that many proteins, of which the signalling capacities depend on reversible palmitoylation, will be discovered in the near future. This stresses the urgent need for further development of small molecule inhibitors of palmitoylation and depalmitoylation in order to study their functions in cellular signalling

    Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release

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    Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10856-013-4859-8) contains supplementary material, which is available to authorized users

    Interactions Between the Physiological Environment and Titanium-Based Implant Materials: From Understanding to Control

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    Titanium and titanium alloys are widely used in different biomedical applications owing to their high biocompatibility, high corrosion resistance, good mechanical properties, and good osseointegration ability. Titanium and its alloys rapidly form a surface oxide layer in air and aqueous environments. This passive and thin (a few nanometers) surface oxide hinders active corrosion and ensures a low metal ion release, enhancing biocompatibility. Compared to that of other biomedical alloys, this surface oxide is exceptionally resistant to chemical attack by halides, primarily chlorides; the presence of fluorides can, in some cases, result in localized corrosion of titanium and its alloys. However, the combination of proteins, inflammatory conditions and bacteria, which for instance generate hydrogen peroxide, can result in a reduction of the corrosion resistance of titanium-based materials. Titanium and its alloying elements, such as aluminum and vanadium, can then be released as ions, which might trigger an immune system response and reduce biocompatibility. Several surface modifications have been proposed in order to improve the bone-bonding ability of titanium and its alloys, facilitate the healing process, and enhance the success of the implant with a decreased risk of micromotions. Moreover, antimicrobial ions/nanoparticles can be added to the surface to reduce the infection risk. Surface modification of titanium (e.g., with artificially grown, micrometer-thick, titanium oxide layers) can significantly increase the corrosion resistance under critical conditions (e.g., inflammatory response and infection); however, the surfaces are not completely inert and the effect of metal ion/nanoparticle release should be carefully taken into account. This chapter reviews and discusses the current strategies for modifying and controlling the surface of titanium-based implant materials, with particular focus on corrosion resistance, bone integration, inflammatory and infection control, and interactions with the physiological environment

    Contribution of residential wood combustion to hourly winter aerosol in Northern Sweden determined by positive matrix factorization

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    International audienceThe combined effect of residential wood combustion (RWC) emissions with stable atmospheric conditions, which is a frequent occurrence in Northern Sweden during wintertime, can deteriorate the air quality even in small towns. To estimate the contribution of RWC to the total atmospheric aerosol loading, the positive matrix factorization (PMF) method was applied to hourly mean particle number size distributions measured in a residential area in Lycksele during winter 2005/2006. The sources were identified based on the particle number size distribution profiles of the PMF factors, the diurnal contributions patterns estimated by PMF for both weekends and weekdays, and correlation of the modeled particle number concentration per factor with measured aerosol mass concentrations (PM10, PM1, and light-absorbing carbon MLAC). Through these analyses, the factors were identified as local traffic (factor 1), local RWC (factor 2), and local RWC plus long-range transport (LRT) of aerosols (factor 3). In some occasions, it was difficult to detach the contributions of local RWC from background concentrations since their particle number size distributions partially overlapped and the model was not able to separate these two sources. As a consequence, we report the contribution of RWC as a range of values, being the minimum determined by factor 2 and the possible maximum as the contributions of both factors 2 and 3. A multiple linear regression (MLR) of observed PM10, PM1, total particle number, and MLAC concentrations is carried out to determine the source contribution to these aerosol variables. The results reveal RWC is an important source of atmospheric particles in the size range 25?606 nm (44?57%), PM10 (36?82%), PM1 (31?83%), and MLAC (40?76%) mass concentrations in the winter season. The contribution from RWC is especially large on weekends between 18:00 LT and midnight whereas local traffic emissions show similar contributions every day

    Penetration of fusidic acid and rifampicin into cerebrospinal fluid in low-grade inflammatory meningitis caused by Staphylococcus epidermidis

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    AbstractCerebrospinal fluid (CSF) concentration-time curves of rifampicin and fusidic acid were studied in a patient with post-operative meningitis caused by Staphylococcus epidermidis. The patient was treated with this combination of antimicrobial agents because of a severe hypersensitivity reaction to vancomycin. Peak CSF concentrations of rifampicin exceeded the MIC by > 60-fold, while those of fusidic acid just reached the MIC. CSF concentrations of fusidic acid were relatively stable within the range reported for patients with uninflamed meninges, but serum levels were surprisingly low. An increase in the metabolism of fusidic acid induced by rifampicin cannot be excluded

    Loss of supervillin causes myopathy with myofibrillar disorganization and autophagic vacuoles

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    The muscle specific isoform of the supervillin protein (SV2), encoded by the SVIL gene, is a large sarcolemmal myosin II- and F-actin-binding protein. Supervillin (SV2) binds and co-localizes with costameric dystrophin and binds nebulin, potentially attaching the sarcolemma to myofibrillar Z-lines. Despite its important role in muscle cell physiology suggested by various in vitro studies, there are so far no reports of any human disease caused by SVIL mutations. We here report four patients from two unrelated, consanguineous families with a childhood/adolescence onset of a myopathy associated with homozygous loss-of-function mutations in SVIL. Wide neck, anteverted shoulders and prominent trapezius muscles together with variable contractures were characteristic features. All patients showed increased levels of serum creatine kinase but no or minor muscle weakness. Mild cardiac manifestations were observed. Muscle biopsies showed complete loss of large supervillin isoforms in muscle fibres by western blot and immunohistochemical analyses. Light and electron microscopic investigations revealed a structural myopathy with numerous lobulated muscle fibres and considerable myofibrillar alterations with a coarse and irregular intermyofibrillar network. Autophagic vacuoles, as well as frequent and extensive deposits of lipoproteins, including immature lipofuscin, were observed. Several sarcolemma-associated proteins, including dystrophin and sarcoglycans, were partially mis-localized. The results demonstrate the importance of the supervillin (SV2) protein for the structural integrity of muscle fibres in humans and show that recessive loss-of-function mutations in SVIL cause a distinctive and novel myopathy

    Attitudinal Changes Toward Body-Worn Cameras: Perceptions of Cameras, Organizational Justice, and Procedural Justice Among Volunteer and Mandated Officers

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    Little is known about officer perceptions of body-worn cameras (BWCs), and whether perceptions change following implementation within their agencies. BWC deployment varies, with some agencies mandating officers to wear BWCs and others using volunteers. Researchers have yet to assess attitudinal differences between volunteers and mandated officers. This study addresses these gaps using data from an evaluation of BWCs in the Phoenix Police Department to examine officer perceptions of the utility of BWCs, perceptions of organizational justice, and support for using procedural justice. We use inverse propensity weighted difference-in-difference models to examine changes in officer perceptions over time between randomly selected officers who were mandated to wear a BWC, BWC volunteers, officers who resisted BWCs, and control officers. We identified limited significant differences in perceptions of BWCs over time, though effect sizes suggest that BWC volunteers and mandated officers were more subdued in their expectations about BWCs at the posttest
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