133 research outputs found
An Investigation of Engagement in the Context of Employer Branding and Social Media
The purpose of the study is to examine how companies are applying employer branding in social media and how these activities affect potential employees’ engagement. Engagement on social media has been analyzed according to the cognitive, emotional and behavioral dimensions using a mixed method content analysis
Language impaired children's listening to speech in noise: a deficit to be remediated?
The objective of the research described below was to investigate the speech perceptual skills of children with specific language impairment (SLI), and the relationship between auditory attention and speech perceptual skills in SLI and agematched controls. Computerised tasks were used to explore the perception of connected speech in the presence of various types of maskers. Apart from the language measures, auditory attention skills, phonological short-term memory and processing and literacy skills were also investigated. The SLI group was expected to perform less well on all these tasks, including the attention measures. Their performance on the speech in noise tasks was of particular interest as few systematic studies have investigated this before. Results generally confirmed a difference in speech perceptual abilities, phonological processing and literacy skills, but not in auditory attention. Most deficits were present only in a subgroup of the SLI children, while others performed similarly to controls. Following the perception study, a sixweek auditory training regime was designed and administered in a subgroup of the language-impaired children. Measures of speech perception in noise were conducted before and after the training and a follow-up assessment of language, attention and literacy abilities was carried out to investigate gains, their generalisation and retention. Implications of the study to language-impaired children’s education and therapy are discussed
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High-temperature sodium nickel chloride battery for electric vehicles
Although the sodium-nickel chloride cell couple has a high voltage (2.59 V) and a high specific energy (790 Wh/kg), the performance of present incarnations of this battery tend to be limited by their power. Because the nickel chloride electrode dominates the resistance and weight of the cell, research on this cell couple at Argonne National Laboratory (ANL) has been primarily directed toward improving both the specific power and energy of the NiCl{sub 2} electrodes. During the course of these investigations a major breakthrough was achieved in lowering the impedance and increasing the usable capacity through the use of chemical additives and a tailored electrode morphology. This improved Ni/NiCl{sub 2} electrode has excellent performance characteristics, wide-temperature operation and fast recharge capability. Modeling studies done on this electrode indicate that a fully developed Na/NiCl{sub 2} battery based on ANL-single tube and bipolar designs would surpass the mid-term and approach the long-term goals of the US Advanced Battery Consortium
Ion exchanges in apatites. Effects on composition and properties
The modification of the composition of apatites materials can be made by several processes corresponding to ion exchange reactions which can conveniently be adapted to current coatings and ceramics and are an alternative to the set up of new synthesis methods. In addition to high temperature thermal treatments, which allow to virtually replace partly or totally monovalent OH- anion of stoichiometric hydroxyapatite by any halogen ion or carbonate, aqueous processes corresponding to dissolution-reprecipitation reactions have also been proposed and used. The most interesting possibilities are however provided by aqueous ion exchange reactions involving nanocrystalline apatites. These apatites are characterised by the existence on the crystal surface of a hydrated layer of loosely bound mineral ions which can be easily exchanged in solution. This layer offers a possibility to trap mineral ions and possibly active molecules which can modify the apatite properties. Such processes are involved in mineralised tissues and could be used in biomaterials for the release of active mineral species
Hydroxyapatite reinforcement of different starch-based polymers affects osteoblast-like cells adhesion/spreading and proliferation
The aim of this study was to determine which, from a range of the starch-based biomaterials, would be more suitable to be used in orthopaedic applications. This included blends of corn starch and ethylene vinyl alcohol (SEVA-C), corn starch and cellulose acetate (SCA), corn starch and polycaprolactone (SPCL) and its composites with increasing percentages of hydroxyapatite (HA). Osteoblast-like cells
(SaOs-2) were cultured in direct contact with the polymers and composites and the effect of the incorporation and of increasing percentages of the ceramic in osteoblast adhesion/proliferation was assessed. In the evaluation of cell adhesion and proliferation rate, two variables were considered; cells adhered to the bottom of the tissue culture polystyrene wells (TCPS) and cells adhered to the surface of the materials, in
order to distinguish, respectively: (i) the effect of possible degradation products released from the materials to the culture medium and (ii) the effect of the surface properties on the osteoblast-like cells. In addition, the morphology of cells adherent to the surface of the starch-based polymers was analysed and correlated with their topography and with other chemical properties previously evaluated.
The proliferation rate was found to differ from blend to blend as well as with the time of culture and with the presence of HA depending on the material. SEVA-C and respective composites systematically presented the higher number of cells comparatively to the other two
blends. SPCL composites were found to be less suitable for cell proliferation. The amount of cells quantified after 7 days of culture, both on the surface and on the wells showed a delay in the proliferation of the cells cultured with SPCL composites comparatively to other materials and to TCPS. SCA composites, however, did support cell adhesion but also induce a slight level of toxicity, which results in delayed proliferation on the cells adhered to the wells.
Cell morphology on the surface of the materials was also, in almost every case, found to be appropriate. In fact, cells were well adhered and spread on the majority of the surfaces. Thus, starch-based biomaterials can be seen as good substrates for osteoblast-adhesion and proliferation that demonstrates their potential to be used in orthopaedic applications and as bone tissue engineering scaffolds.Fundação para a Ciência e a Tecnologia (FCT
Slow Transformation of Mechanically Dehydroxylated Kaolinite to Kaolinite - An Aged Mechanochemically Activated Formamide-Intercalated Koalinite Study
Formamide-intercalated high defect kaolinite which was mechanochemically activated for periods of time up to 6 h has been aged for up to 1 year. These modified materials were studied using a combination of X-ray diffraction, thermal analysis and DRIFT spectroscopy. Ageing of the formamide-intercalated mechanochemically activated kaolinite results in de-intercalation of the formamide and the de-intercalated kaolinite returns to its original d-spacing. Thermal analysis shows that the temperature of dehydration and dehydroxylation increase by up to 30 °C. The temperature of the dehydroxylation of the aged samples was identical to that of the untreated kaolinite. The DRIFT spectroscopy showed that the spectrum of the aged samples approached that of the untreated kaolinite. The kaolinite showed partial de-intercalation and the 6 h sample had reformed to a mineral resembling the untreated kaolinite. The process of ageing the mechanochemically activated kaolinite enabled the reformation of the kaolinite
ChemInform Abstract: The Surface Chemistry of Molybdena-Alumina Catalysts Reduced in H2 at Elevated Temperatures
ChemInform Abstract: The Effects of Pressure on the Hydrogenation of Benzene and Naphthalene Over Reduced and Sulfided Molybdena-Alumina Catalysts.
Reconstruction of the 8pi Gamma Ray Spectrometer for the Development of Medical Imaging Technology
Medical imaging takes advantage of the detection of penetrating radiation to provide non-invasive tools for medical procedures. More specifically, specialized gamma-ray detectors such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) scanners can be used to track the flow of a radioactive tracer in a patient and yield data about their condition. The radiotracer compound can be modified to target specific bodily functions or tracts, thus improving the contrast of a scan. At SFU, the 8pi spectrometer has been established as a framework for conducting studies to advance imaging software, detector systems, and radiotracer technology.
This presentation will outline the rebuild process of 8pi, (both electrical and mechanical), the application of digital signal processing technology to 8pi to provide superior detection systems at a decreased cost, and how 8pi can be used by the SFU scientific community to further research in the medical field.
 
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