396 research outputs found

    The development of a “holistic” model incorporating business strategy formulation with IdM strategy formulation

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    Identity management (IdM) not only improves the process of creating and maintaining digital identities across the business systems, but, if implemented successfully it can contribute to the strengthening and positioning of the business for success. In order to lead successful IdM implementation organizations need to step back and determine a course of action that would solve enterprise-wide issues. Short-sighted actions can lead to confusion, unnecessary expenses and the delay of beneficial results. This paper presents guidelines for application of strategic management principles regarding IdM implementation. By gathering and interpreting information from a real life case study on how a typical large South African business organization approached its IdM implementation, a theoretical model incorporating IdM implementation planning within business strategy formulation is proposed. This study results reveals five important guideline steps regarding IdM implementation

    Tailoring Fibre Structure Enabled by X-ray Analytics for Targeted Biomedical Applications

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    The rising interest in designing fibres via spinning techniques combining the properties of various polymeric materials into advanced functionalised materials is directed towards targeted biomedical applications such as drug delivery, wearable sensors or tissue engineering. Understanding how these functional polymers exhibit multiscale structures ranging from the molecular level to nano-, micro-and millimetre scale is a key prerequisite for their challenging applications that can be addressed by a non-destructive X-ray based analytical approach. X-ray multimodalities combining X-ray imaging, scattering and diffraction allow the study of morphology, molecular structure, and the analysis of nano-domain size and shape, crystallinity and preferential orientation in 3D arrangements. The incorporation of X-ray analytics in the design process of polymeric fibers via their nanostructure under non-ambient conditions (i.e. temperature, mechanical load, humidity…) allows for efficient optimization of the fabrication process as well as quality control along the product lifetime under operating environmental conditions. Here, we demonstrate the successful collaboration between the laboratory of Biomimetic Textiles and Membranes and the Center of X-ray Analytics at Empa for the design, characterisation and optimisation of advanced functionalised polymeric fibrous material systems

    Cyanine platelet single crystals: Growth, crystal structure and optical spectra

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    © the Owner Societies. Crystalline organic semiconducting materials are much in demand for multiple electronic and optoelectronic device applications. Here, solution grown ultrathin rhombic crystals of a trimethine carbocyanine anionic dye are used to establish relationships between structural and optical properties. The dye crystallized in the monoclinic space group P21/c featuring alternating layers of molecules in two different herringbone type patterns, with perchlorate counterions located mostly within one of the two layers. Micro transmittance spectroscopy revealed a broadened spectrum compared to those obtained in solution and in an amorphous thin film. Using polarized light, transmission spectroscopy revealed strong low-energy and weak high-energy bands polarized along the crystallographic b- and c-axis, respectively. Using the extended dipole approximation, significant exciton couplings are predicted between neighboring molecules in the crystal, of the order of the intrinsic monomer reorganization energies associated with nuclear relaxation after excitation, depicting a complex spectral scenario. The exciton coupling pattern explains the relative energies of the b- and c-polarized components but the observed intensities are opposite to expectations based on chromophore alignment within the crystal

    Thoracolumbar transitional vertebrae : quantitative differentiation and associated numeric variation in the vertebral column using skeletal remains

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    DATA AVAILABILITY : Data is available on the University of Pretoria public database.Transitional vertebrae at the thoracolumbar region are called thoracolumbar transitional vertebrae (TLTV) and retain physical features from the thoracic and lumbar regions. Since TLTV were first classified 40 years ago, there has been much discrepancy regarding its features, identification and clinical relevance. Vertebral body levels are used in the medical field as a frame of reference to locate specific organs, vessels, nerves or landmarks. Any numeric variation or deviation in the vertebral column may lead to clinical errors. Previous findings have suggested a high association between numeric variation and the presence of TLTV. Therefore, the aim of this study was to identify the types of TLTV observed and to identify any possible associated numeric variation in the vertebral column. This study also aimed to validate the established technique to quantitatively differentiate TLTV from T12 and L1 at the thoracolumbar junction using skeletal remains from a South African population group. Skeletal remains (n= 187) remains from the Pretoria bone collection were assessed. Measurements were taken of the angle of the superior zygapophyseal processes of the last thoracic vertebra (T12), the first lumbar (L1), and identified TLTV. The results indicate a TLTV prevalence of 35% (n= 66/187). The results show that each vertebral type (T12, L1, TLTV) fall into independent confidence intervals: T12 is 188° ± 9.22 (CI: 187° <μ< 189.6°), 110° ± 7.52 (CI: 109.2° <μ< 111.3°) in L1, and 135° ± 24.51 (CI: 130.4° <μ< 139.1°) in the TLTV. This study observed that 70% of cases with TLTV was associated with numeric variation in the spine, both homeotic and meristic and that TLTV has a 35% prevalence. The results clearly show that quantitative morphometric analysis can effectively differentiate TLTV from other vertebral types at the thoracolumbar junction in skeletal remains.http://www.wileyonlinelibrary.com/journal/joaAnatom

    Si/SiGe quantum cascade superlattice designs for terahertz emission

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    Quantum cascade lasers are compact sources that have demonstrated high output powers at THz frequencies. To date all THz quantum cascade lasers have been realized in III-V materials. Results are presented from Si1−xGex quantum cascade superlattice designs emitting at around 3 THz which have been grown in two different chemical vapor deposition systems. The key to achieving successful electroluminescence at THz frequencies in a p-type system has been to strain the light-hole states to energies well above the radiative subband states. To accurately model the emission wavelengths, a 6-band k.p tool which includes the effects of non-abrupt heterointerfaces has been used to predict the characteristics of the emitters. X-ray diffraction and transmission electron microscopy have been used along with Fourier transform infrared spectroscopy to fully characterise the samples. A number of methods to improve the gain from the designs are suggested

    Clinical anatomy of the anterior cruciate ligament and pre-operative prediction of ligament length

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    BACKGROUND : Ligament grafts used in anterior cruciate ligament (ACL) reconstruction need to be the correct length for proper functioning. If the graft length is incorrect, the patient could risk knee instability, loss of range of motion, or failure of graft fixation. Easier and time-efficient reconstruction will be facilitated if the length of the ACL is predicted in advance. Apart from examining the morphological properties of the ACL, this study aimed to determine whether the epicondylar width of an individual can be used to predict ACL length and thereby assist in restoring the normal anatomy of the ACL. METHODS : Ninety-one adult cadavers were studied. Patellar ligament (PL) length, ACL length, ACL width and the maximum femoral epicondylar width (FECW) were measured. RESULTS : The morphology of the ACL and PL was determined. The results revealed that FECW was the most reliable predictor of ACL length. A linear regression formula was developed in order to determine ACL length by measuring maximum FECW. CONCLUSIONS : ACL and PL morphology compared well with the results found in previous studies. An individual's FECW can be used to predict ACL length pre-operatively. These results could improve pre-operative planning of ACL reconstruction.http://www.scielo.org.za/scielo.php?script=sci_serial&pid=1681-150X&lng=pt&nrm=isoAnatomyStatistic

    Osteopontin Is Required for the Early Onset of High Fat Diet-Induced Insulin Resistance in Mice

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    Insulin resistance is manifested in muscle, adipose tissue, and liver and is associated with adipose tissue inflammation. The cellular components and mechanisms that regulate the onset of diet-induced insulin resistance are not clearly defined.We initially observed osteopontin (OPN) mRNA over-expression in adipose tissue of obese, insulin resistant humans and rats which was normalized by thiazolidinedione (TZD) treatment in both species. OPN regulates inflammation and is implicated in pathogenic maladies resulting from chronic obesity. Thus, we tested the hypothesis that OPN is involved in the early development of insulin resistance using a 2-4 week high fat diet (HFD) model. OPN KO mice fed HFD for 2 weeks were completely protected from the severe skeletal muscle, liver and adipose tissue insulin resistance that developed in wild type (WT) controls, as determined by hyperinsulinemic euglycemic clamp and acute insulin-stimulation studies. Although two-week HFD did not alter body weight or plasma free fatty acids and cytokines in either strain, HFD-induced hyperleptinemia, increased adipose tissue inflammation (macrophages and cytokines), and adipocyte hypertrophy were significant in WT mice and blunted or absent in OPN KO mice. Adipose tissue OPN protein isoform expression was significantly altered in 2- and 4-week HFD-fed WT mice but total OPN protein was unchanged. OPN KO bone marrow stromal cells were more osteogenic and less adipogenic than WT cells in vitro. Interestingly, the two differentiation pathways were inversely affected by HFD in WT cells in vitro.The OPN KO phenotypes we report reflect protection from insulin resistance that is associated with changes in adipocyte biology and adipose tissue inflammatory status. OPN is a key component in the development of HFD-induced insulin resistance

    Electromagnetic levitation containerless processing of metallic materials in microgravity: thermophysical properties

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    Transitions from the liquid to the solid state of matter are omnipresent. They form a crucial step in the industrial solidification of metallic alloy melts and are greatly influenced by the thermophysical properties of the melt. Knowledge of the thermophysical properties of liquid metallic alloys is necessary in order to gain a tight control over the solidification pathway, and over the obtained material structure of the solid. Measurements of thermophysical properties on ground are often difficult, or even impossible, since liquids are strongly influenced by earth’s gravity. Another problem is the reactivity of melts with container materials, especially at high temperature. Finally, deep undercooling, necessary to understand nucleus formation and equilibrium as well as nonequilibrium solidification, can only be achieved in a containerless environment. Containerless experiments in microgravity allow precise benchmark measurements of thermophysical properties. The electromagnetic levitator ISS-EML on the International Space Station (ISS) offers perfect conditions for such experiments. This way, data for process simulations is obtained, and a deeper understanding of nucleation, crystal growth, microstructural evolution, and other details of the transformation from liquid to solid can be gained. Here, we address the scientific questions in detail, show highlights of recent achievements, and give an outlook on future work

    Tb3+-doped LaF3 nanocrystals for correlative cathodoluminescence electron microscopy imaging with nanometric resolution in focused ion beam-sectioned biological samples

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    Here, we report the use of rare earth element-doped nanocrystals as probes for correlative cathodoluminescence electron microscopy (CCLEM) bioimaging. This first experimental demonstration shows potential for the simultaneous acquisition of luminescence and electron microscopy images with nanometric resolution in focused ion beam cut biological samples
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