47 research outputs found

    Simultaneous surface acoustic wave and surface plasmon resonance measurements: electrodeposition and biological interactions monitoring

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    We present results from an instrument combining surface acoustic wave (SAW) propagation and surface plasmon resonance (SPR) measurements. The objective is to use two independent methods, the former based on adsorbed mass change measurements and the latter on surface dielectric properties variations, to identify physical properties of protein layers, and more specifically their water content. We display mass sensitivity calibration curves using electrodeposition of copper leading to a sensitivity in liquid of 150±15\pm15 cm2/gcm^2/g for the Love mode device used here, and the application to monitoring biological processes. The extraction of protein layer thickness and protein to water content ratio is also presented for S-layer proteins under investigation. We obtain respectively 4.7±\pm0.7 nm and 75±\pm15%.Comment: 13 pages, 4 figure

    Reporter gene-expressing bone marrow-derived stromal cells are immune-tolerated following implantation in the central nervous system of syngeneic immunocompetent mice

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    <p>Abstract</p> <p>Background</p> <p>Cell transplantation is likely to become an important therapeutic tool for the treatment of various traumatic and ischemic injuries to the central nervous system (CNS). However, in many pre-clinical cell therapy studies, reporter gene-assisted imaging of cellular implants in the CNS and potential reporter gene and/or cell-based immunogenicity, still remain challenging research topics.</p> <p>Results</p> <p>In this study, we performed cell implantation experiments in the CNS of immunocompetent mice using autologous (syngeneic) luciferase-expressing bone marrow-derived stromal cells (BMSC-Luc) cultured from ROSA26-L-S-L-Luciferase transgenic mice, and BMSC-Luc genetically modified using a lentivirus encoding the enhanced green fluorescence protein (eGFP) and the puromycin resistance gene (Pac) (BMSC-Luc/eGFP/Pac). Both reporter gene-modified BMSC populations displayed high engraftment capacity in the CNS of immunocompetent mice, despite potential immunogenicity of introduced reporter proteins, as demonstrated by real-time bioluminescence imaging (BLI) and histological analysis at different time-points post-implantation. In contrast, both BMSC-Luc and BMSC-Luc/eGFP/Pac did not survive upon intramuscular cell implantation, as demonstrated by real-time BLI at different time-points post-implantation. In addition, ELISPOT analysis demonstrated the induction of IFN-Îł-producing CD8+ T-cells upon intramuscular cell implantation, but not upon intracerebral cell implantation, indicating that BMSC-Luc and BMSC-Luc/eGFP/Pac are immune-tolerated in the CNS. However, in our experimental transplantation model, results also indicated that reporter gene-specific immune-reactive T-cell responses were not the main contributors to the immunological rejection of BMSC-Luc or BMSC-Luc/eGFP/Pac upon intramuscular cell implantation.</p> <p>Conclusion</p> <p>We here demonstrate that reporter gene-modified BMSC derived from ROSA26-L-S-L-Luciferase transgenic mice are immune-tolerated upon implantation in the CNS of syngeneic immunocompetent mice, providing a research model for studying survival and localisation of autologous BMSC implants in the CNS by real-time BLI and/or histological analysis in the absence of immunosuppressive therapy.</p

    A novel explanation for the increased conductivity in annealed Al-doped ZnO: an insight into migration of aluminum and displacement of zinc

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    A combined experimental and first-principles study is performed to study the origin of conductivity in ZnO:Al nanoparticles synthesized under controlled conditions via a reflux route using benzylamine as a solvent. The experimental characterization of the samples by Raman, nuclear magnetic resonance (NMR) and conductivity measurements indicates that upon annealing in nitrogen, the Al atoms at interstitial positions migrate to the substitutional positions, creating at the same time Zn interstitials. We provide evidence for the fact that the formed complex of AlZn and Zni corresponds to the origin of the Knight shifted peak (KS) we observe in 27Al NMR. As far as we know, the role of this complex has not been discussed in the literature to date. However, our first-principles calculations show that such a complex is indeed energetically favoured over the isolated Al interstitial positions. In our calculations we also address the charge state of the Al interstitials. Further, Zn interstitials can migrate from AlZn and possibly also form Zn clusters, leading to the observed increased conductivity

    Occupational Therapy Intervention with Children Survivors of War

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    A preventive occupational therapy program with children surviving the Kosovo conflict is examined. The objective of the program was to facilitate the emotional expression of traumatic experiences in order to prevent the development of future psychological problems. The intervention was based on a community-centred approach with spirituality as a central focus of the intervention.The Model of Human Occupation and the Occupational Performance Process Model were utilized to guide the identification and intervention of occupational performance issues.The children’s return from a land of war to a land of children demonstrates the potential of occupational therapy intervention in this field. With increasing awareness of populations facing social and political challenges, there is a growing importance of the concept of occupational justice and the need to work against occupational apartheid.Cet article décrit un programme de prévention en ergothérapie qui était destiné aux enfants ayant survécu au conflit du Kosovo. L’objectif du programme était d’aider les enfants à exprimer les émotions qu’ils avaient ressenties lors d’expériences traumatiques afin de prévenir l’apparition de problèmes psychologiques. L’intervention était basée sur une approche communautaire s’articulant autour de la spiritualité. Le Modèle de l’occupation humaine et le Modèle du processus d’intervention dans le rendement occupationnel ont été utilisés pour cibler les difficultés en matière de rendement occupationnel et pour déterminer les interventions requises. Le retour des enfants d’un monde de guerre vers le monde de l’enfance démontre la possibilité de proposer une intervention ergothérapique dans ce domaine. La conscientisation de plus en plus grand face à la détresse des populations confrontées à des problèmes politiques et sociaux entraîne une augmentation de l’importance du concept de la justice occupationnelle et du besoin de lutter contre l’apartheid occupationnel

    Comparative Study on the Therapeutic Potential of Neurally Differentiated Stem Cells in a Mouse Model of Multiple Sclerosis

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    Background: Transplantation of neural stem cells (NSCs) is a promising novel approach to the treatment of neuroinflammatory diseases such as multiple sclerosis (MS). NSCs can be derived from primary central nervous system (CNS) tissue or obtained by neural differentiation of embryonic stem (ES) cells, the latter having the advantage of readily providing an unlimited number of cells for therapeutic purposes. Using a mouse model of MS, we evaluated the therapeutic potential of NSCs derived from ES cells by two different neural differentiation protocols that utilized adherent culture conditions and compared their effect to primary NSCs derived from the subventricular zone (SVZ). Methodology/Principal Findings: The proliferation and secretion of pro-inflammatory cytokines by antigen-stimulated splenocytes was reduced in the presence of SVZ-NSCs, while ES cell-derived NSCs exerted differential immunosuppressive effects. Surprisingly, intravenously injected NSCs displayed no significant therapeutic impact on clinical and pathological disease outcomes in mice with experimental autoimmune encephalomyelitis (EAE) induced by recombinant myelin oligodendrocyte glycoprotein, independent of the cell source. Studies tracking the biodistribution of transplanted ES cellderived NSCs revealed that these cells were unable to traffic to the CNS or peripheral lymphoid tissues, consistent with the lack of cell surface homing molecules. Attenuation of peripheral immune responses could only be achieved through multiple high doses of NSCs administered intraperitoneally, which led to some neuroprotective effects within the CNS

    De nieuwe VZW, een hele onderneming

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    A survey on tax compliance costs of Flemish SMEs: Magnitude and determinants

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    This study presents survey evidence on the magnitude and determinants of tax compliance costs in Flemish small and medium-sized enterprises (SMEs). Data were obtained from an internet questionnaire among members of a professional network of Flemish entrepreneurs, called VOKA. Analyzing a sample of 151 Flemish SMEs, we find that the tax compliance costs – exceeding over seven percent of gross added value – are relatively high. VAT, labor taxes and corporate taxes are the main components of tax compliance costs. In addition, our evidence confirms the regressivity hypothesis, according to which smaller companies face relatively higher compliance costs. Furthermore, industry, age and the proportion of blue-collar workers prove to be determining factors of relative compliance costs. Our study concludes by formulating a number of policy recommendations that might contribute to lower compliance costs.
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