91 research outputs found
Krötenbesen und Geisterbohne : Pflanzennamen in Tenkodogo (Burkina Faso)
UnermĂŒdliche Pflanzer sind die meisten Mosi, die - gemeinsam mit den Bisa - in Tenkodogo, Verwaltungshauptstadt der Provinz Boulgou im SĂŒdosten Burkina Fasos, die Bevölkerungsmehrheit stellen. Im Zentrum ihrer agrarisch geprĂ€gten Vorstellungswelt stehen die Kulturpflanzen, vor allem die Hirsearten Sorghum bicolor und Pennisetum americanum, von deren gutem Gedeihen das Ăberleben in jenem Gebiet weitgehend abhĂ€ngt. Diese in der tĂ€glichen ErnĂ€hrung unentbehrlichen Pflanzen spielen allerdings in unseren AusfĂŒhrungen keine Rolle. Wir wollen vielmehr zeigen, wonach selten oder nicht genutze Wildpflanzen, vor allem KrĂ€uter und GrĂ€ser, ihren Namen erhielten. Ihre Taxonomie stĂŒtzt sich wesentlich auf Ordnungssysteme des Alltags, basierend auf der "natĂŒrlich-sozialen" Organisation und Opposition von Drinnen und DrauĂen, welche durch die GegensĂ€tze Kulturland und Busch, Nutzpflanze und Unkraut, Haustier und Wildtier, GruppenoberhĂ€upter und gesellschaftliche AuĂenseiter, Menschen und Geister reprĂ€sentiert werden
Attracting future civil servants with public values? An experimental study on employer branding
A frequently cited recommendation of public service motivation (PSM) research is to use PSM in the context of HR marketing. However, empirical evidence demonstrating the usefulness of addressing PSM in the recruitment process is limited. Moreover, we know little about the relative importance of PSM for public employersâ attractiveness. We address this gap using an experimental research design to investigate whether public service motivated individuals differ from extrinsically motivated individuals in terms of their attraction to organizations that emphasize either âtraditionalâ public or private values in their employer branding. Our findings indicate that public service motivated individuals are attracted neither to public nor to private values in employer branding. Furthermore, individuals with very high levels of extrinsic motivation are more attracted to private values employer branding than to public values employer branding and to the control group
L'homme et l'environnement chez les Mosi de Tenkodogo
Nos travaux dans les villages mosi de la région de Tenkodogo, au centreest du Burkina Faso, portent directement sur le thÚme central du Projet de Recherche de l'Université de Francfort: Les relations mutuelles entre la culture d'une population et son milieu naturel. Sur la base d'une étude approfondie de l'environnement naturel, on devrait répondre à la question suivante: comment les Hommes conçoivent et estimentils ce milieu, quelles valeurs lui attribueton; en outre, sur la base de quels principes et d'aprÚs quels critÚres de préférence utilisentils leurs sols en tant que cultivateurs; quelles raisons déterminent-elles l'expansion des Mosi méridionaux dans cette aire géographique, la fondation des villages ainsi que leur dévéloppement démographique. Enfin quel est l'impact de tout cela sur l'environnement naturel, c'est-à -dire quelles sont les conséquences écologiques des conceptions et comportements susmentionnés. Nos recherches sur le terrain débutÚrent en 1991 sous la forme d'une collaboration interdisciplinaire étroite entre l'ethnologie, la géographie physique et la botanique. L'objectif à long terme est une comparaison entre les Mosi méridionaux, leurs voisins bisa, les Gulmance et enfin un groupe mosi du nord
A new bone substitute developed from 3D-prints of polylactide (PLA) loaded with collagen I : an in vitro study
Although a lot of research has been performed, large segmental bone defects caused by trauma, infection, bone tumors or revision surgeries still represent big challenges for trauma surgeons. New and innovative bone substitutes are needed. Three-dimensional (3D) printing is a novel procedure to create 3D porous scaffolds that can be used for bone tissue engineering. In the present study, solid discs as well as porous cage-like 3D prints made of polylactide (PLA) are coated or filled with collagen, respectively, and tested for biocompatibility and endotoxin contamination. Microscopic analyses as well as proliferation assays were performed using various cell types on PLA discs. Stromal-derived factor (SDF-1) release from cages filled with collagen was analyzed and the effect on endothelial cells tested. This study confirms the biocompatibility of PLA and demonstrates an endotoxin contamination clearly below the FDA (Food and Drug Administration) limit. Cells of various cell types (osteoblasts, osteoblast-like cells, fibroblasts and endothelial cells) grow, spread and proliferate on PLA-printed discs. PLA cages loaded with SDF-1 collagen display a steady SDF-1 release, support cell growth of endothelial cells and induce neo-vessel formation. These results demonstrate the potential for PLA scaffolds printed with an inexpensive desktop printer in medical applications, for example, in bone tissue engineering
Evaluation of bone sialoprotein coating of three-dimensional printed calcium phosphate scaffolds in a calvarial defect model in mice
The bioactive coating of calcium phosphate cement (CPC) is a promising approach to enhance the bone-healing properties of bone substitutes. The purpose of this study was to evaluate whether coating CPCs with bone sialoprotein (BSP) results in increased bone formation. Forty-five female C57BL/6NRj mice with an average age of six weeks were divided into three groups. Either a BSP-coated or an uncoated three-dimensional plotted scaffold was implanted into a drilled 2.7-mm diameter calvarial defect, or the defect was left empty (control group; no CPC). Histological analyses revealed that BSP-coated scaffolds were better integrated into the local bone stock eight weeks after implantation. Bone volume/total volume (BV/TV) ratios and bone thickness at the bone-implant contact were analyzed via micro computed tomography (”CT) after eight weeks. BSP-coated scaffolds and uncoated CPC scaffolds increased bone thickness in comparison to the control (CPC + BSP: 691.1 ± 253.5 ”m, CPC: 603.1 ± 164.4 ”m, no CPC: 261.7 ± 37.8 ”m, p < 0.01). Accordingly, BV/TV was enhanced in both scaffold groups (CPC + BSP: 1.3 ± 0.5%, CPC: 0.9 ± 0.5%, no CPC: 0.2 ± 0.3%, p < 0.01). The BSP coating showed a tendency towards an increased bone thickness (p = 0.18) and BV/TV (p = 0.18) in comparison to uncoated CPC scaffolds. However, a significant increase in bone formation through BSP coating was not found
The effect of the pro-inflammatory cytokine tumor necrosis factor-alpha on human joint capsule myofibroblasts
Introduction: Previous studies have shown that the number of myoblastically differentiated fibroblasts known as myofibroblasts (MFs) is significantly increased in stiff joint capsules, indicating their crucial role in the pathogenesis of post-traumatic joint stiffness. Although the mode of MFs' function has been well defined for different diseases associated with tissue fibrosis, the underlying mechanisms of their regulation in the pathogenesis of post-traumatic joint capsule contracture are largely unknown. Methods: In this study, we examined the impact of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) on cellular functions of human joint capsule MFs. MFs were challenged with different concentrations of TNF-alpha with or without both its specifically inactivating antibody infliximab (IFX) and cyclooxygenase-2 (COX2) inhibitor diclofenac. Cell proliferation, gene expression of both alpha-smooth muscle actin (alpha-SMA) and collagen type I, the synthesis of prostaglandin derivates E(2), F(1A), and F(2A), as well as the ability to contract the extracellular matrix were assayed in monolayers and in a three-dimensional collagen gel contraction model. The a-SMA and COX2 protein expressions were evaluated by immunofluorescence staining and Western blot analysis. Results: The results indicate that TNF-alpha promotes cell viability and proliferation of MFs, but significantly inhibits the contraction of the extracellular matrix in a dose-dependent manner. This effect was associated with downregulation of a-SMA and collagen type I by TNF-alpha application. Furthermore, we found a significant time-dependent upregulation of prostaglandin E(2) synthesis upon TNF-alpha treatment. The effect of TNF-alpha on COX2-positive MFs could be specifically prevented by IFX and partially reduced by the COX2 inhibitor diclofenac. Conclusions: Our results provide evidence that TNF-alpha specifically modulates the function of MFs through regulation of prostaglandin E(2) synthesis and therefore may play a crucial role in the pathogenesis of joint capsule contractures
An Additively Manufactured Sample Holder to Measure the Controlled Release of Vancomycin from Collagen Laminates
The controlled release of antibiotics prevents the spread of pathogens and thereby improves healing processes in regenerative medicine. However, high concentrations may interfere with healing processes. It is therefore advantageous to use biodegradable materials for a controlled release. In particular, multilayer materials enable differential release at different surfaces. For this purpose, collagen sheets of different properties can be bonded by photochemical crosslinking. Here, we present the development and application of an easily accessible, additively manufactured sample holder to study the controlled release of vancomycin from modularly assembled collagen laminates in two directions. As proof-of-concept, we show that laminates of collagen sheets covalently linked by rose bengal and green light crosslinking (RGX) can be tightly inserted into the device without leakage from the upper to lower cavity. We used this sample holder to detect the release of vancomycin from symmetrically and asymmetrically loaded two-layer and three-layer collagen laminates into the upper and lower cavity of the sample holder. We show that these collagen laminates are characterized by a collagen type-dependent vancomycin release, enabling the control of antibiotic release profiles as well as the direction of antibiotic release
3D-Printed PLA-Bioglass Scaffolds with Controllable Calcium Release and MSC Adhesion for Bone Tissue Engineering
Large bone defects are commonly treated by replacement with auto- and allografts, which have substantial drawbacks including limited supply, donor site morbidity, and possible tissue rejection. This study aimed to improve bone defect treatment using a custom-made filament for tissue engineering scaffolds. The filament consists of biodegradable polylactide acid (PLA) and a varying amount (up to 20%) of osteoconductive S53P4 bioglass. By employing an innovative, additive manufacturing technique, scaffolds with optimized physico-mechanical and biological properties were produced. The scaffolds feature adjustable macro- and microporosity (200â2000 ”m) with adaptable mechanical properties (83â135 MPa). Additionally, controllable calcium release kinetics (0â0.25 nMol/”L after 24 h), tunable mesenchymal stem cell (MSC) adhesion potential (after 24 h by a factor of 14), and proliferation (after 168 h by a factor of 18) were attained. Microgrooves resulting from the 3D-printing process on the surface act as a nucleus for cell aggregation, thus being a potential cell niche for spheroid formation or possible cell guidance. The scaffold design with its adjustable biomechanics and the bioglass with its antimicrobial properties are of particular importance for the preclinical translation of the results. This study comprehensibly demonstrates the potential of a 3D-printed bioglass composite scaffold for the treatment of critical-sized bone defects
Exposure to radial extracorporeal shock waves modulates viability and gene expression of human skeletal muscle cells: a controlled in vitro study
Background: Recent clinical and animal studies have shown that extracorporeal shock wave therapy has a promoting influence on the healing process of musculoskeletal disorders. However, the underlying biological effects of extracorporeal shock wave therapy on human skeletal muscle cells have not yet been investigated. Methods: In this study, we investigated human skeletal muscle cells after exposure to radial extracorporeal shock waves in a standardized in vitro setup. Cells were isolated from muscle specimens taken from adult patients undergoing spine surgery. Primary muscle cells were exposed once or twice to radial extracorporeal shock waves in vitro with different energy flux densities. Cell viability and gene expression of the paired box protein 7 (Pax7), neural cell adhesion molecule (NCAM), and myogenic factor 5 (Myf5) and MyoD as muscle cell markers were compared to non-treated muscle cells that served as controls. Results: Isolated muscle cells were positive for the hallmark protein of satellite cells, Pax7, as well as for the muscle cell markers NCAM, MyoD, and Myf5. Exposure to radial extracorporeal shock waves at low energy flux densities enhanced cell viability, whereas higher energy flux densities had no further significant impact. Gene expression analyses of muscle specific genes (Pax7, NCAM, Myf5, and MyoD) demonstrated a significant increase after single exposure to the highest EFD (4 bar, 0.19 mJ/mm(2)) and after double exposure with the medium EFDs (2 and 3 bar;0.09 and 0.14 mJ/mm(2), respectively). Double exposure of the highest EFD, however, results in a significant down-regulation when compared to single exposure with this EFD. Conclusions: This is the first study demonstrating that radial extracorporal shock wave therapy has the potential to modulate the biological function of human skeletal muscle cells. Based on our experimental findings, we hypothesize that radial extracorporal shock wave therapy could be a promising therapeutic modality to improve the healing process of sports-related structural muscle injuries
3D-Printing of Hierarchically Designed and Osteoconductive Bone Tissue Engineering Scaffolds
In Bone Tissue Engineering (BTE), autologous bone-regenerative cells are combined with a scaffold for large bone defect treatment (LBDT). Microporous, polylactic acid (PLA) scaffolds showed good healing results in small animals. However, transfer to large animal models is not easily achieved simply by upscaling the design. Increasing diffusion distances have a negative impact on cell survival and nutrition supply, leading to cell death and ultimately implant failure. Here, a novel scaffold architecture was designed to meet all requirements for an advanced bone substitute. Biofunctional, porous subunits in a load-bearing, compression-resistant frame structure characterize this approach. An open, macro- and microporous internal architecture (100 ”mâ2 mm pores) optimizes conditions for oxygen and nutrient supply to the implantâs inner areas by diffusion. A prototype was 3D-printed applying Fused Filament Fabrication using PLA. After incubation with Saos-2 (Sarcoma osteogenic) cells for 14 days, cell morphology, cell distribution, cell survival (fluorescence microscopy and LDH-based cytotoxicity assay), metabolic activity (MTT test), and osteogenic gene expression were determined. The adherent cells showed colonization properties, proliferation potential, and osteogenic differentiation. The innovative design, with its porous structure, is a promising matrix for cell settlement and proliferation. The modular design allows easy upscaling and offers a solution for LBDT
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