320 research outputs found

    Flexibility and Trust – About the Meaning of Trust in Changing Processes

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    Fundamental economic and social changes have strongly influenced the conditions under which companies have to operate during the last couple of years. The dynamics of the business environment, which are among other things increasingly forced by the globalization of markets, development of new technologies and subsequently growing competitive pressure, requires that companies adapt to their environment not only reactive, but rather act proactively to exist on the market permanently. This means, that in companies radical change processes are not even uncommon in addition to permanent changes. Regarding the success of any change process it is of vital importance that the concerned employees and departments are involved in the success of the project and cooperate closely. For this reason trust is becoming more and more important in business environment, especially against the backdrop of economic crisis, of mergers, outsourcing, short-time work and job loss. The setup and permanent care of a trustworthy corporate culture, the content of which includes the constructive handling through management of the anxieties and emotions of the employees concerning upcoming changes, finally provides the basis for successful cooperation. Currently there is no scientific consensus about what trust is, how it can be measured, evaluated and influenced. These issues are now being investigated by empirical studies. Thus, the meaning of 'professional' trust was determined by means of a quantitative questionnaire. One aim of the empirical study was to investigate the existence of trust-promoting and trust-inhibitory factors in companies and to generate rankings regarding their importance for the employees. The perceptions should be the basis to build and maintain a reliable culture of trust in companies, especially during the implementation of change processes.:1. Introduction 2. Meaning of Trust in Research 3. To Change with Trust 4. Method 5. Results 5.1 Trust-Aiding and Trust-Repressing Factors 5.2 Measuring and Evaluating Trust 6. Perspective Literatur

    Bioengineering approaches to emulate the stem cell niche

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    Stem cell therapies hold tremendous potential for tissue and organ regeneration. Yet, there remains significant need for better ex vivo culture and manipulation methods. On the one hand, many tissue-specific stem cells cannot be propagated without causing rapid deviations in cellular phenotype. On the other hand, outside of a developing organism, it remains very difficult to differentiate stem cells into mature functional cell types. Such protocols could help to build more effective and predictive pre-clinical models that would reduce or even replace animal studies. Manipulating a stem cell in vitro requires a thorough understanding of its microenvironment, or niche, and how niche factors influence stem cell fate. A customizable microarray platform was therefore developed to examine the interplay of biochemical and mechanical signals on stem cell behavior. This array was implemented to study combinations of 12 different proteins with varying substrate stiffness and their effect on the adipogenic differentiation of human mesenchymal stem cells (MSCs). These cells and their differentiated progenies are of high therapeutic relevance for skeletal tissue regeneration and have also been implied as niche-modulating neighbors of hematopoietic stem cells (HSCs) in the bone marrow (BM). Using this combinatorial approach, substrate stiffness was found to be the major determinant of the frequency of lipid accumulation in MSCs, while the lipid content was found to be strongly driven by the biochemical context. To further understand how niche cells together with stem cells self-organize to form a functional tissue, three-dimensional (3D) organ-mimicking structures from spheroids of pluri- and multi-potent have recently been developed. These systems, termed organoids, are expected to provide instrumental insights into tissue or organ development and they could be of great use for disease-specific drug screenings and to generate clinically transplantable tissues. However, current protocols for organoid generation remain highly inefficient and irreproducible. To perform the high-throughput aggregation of one or multiple cell types and to allow their long-term culture, a high-density array of U-shaped microwells was developed. This platform was used to initiate 3D co-cultures of the hematopoiesis-supportive cell line OP9 together with HSCs. To expand on the potential of this co-culture model to study more relevant primary BM cells, uniform clonal mesensphere cultures from human MSCs were established. However, restricted knowledge about the phenotypic identity of both niche and stem cell is a major limitation to initiate these co-cultures in vitro. Therefore, in this thesis a cell-targeting approach through covalent SNAP-tag-based cell-pairing is proposed. Specifically, SNAP-tag fusion proteins expressed on cell membranes were targeted to form covalent bonds with substrates that harbor the SNAP-tag substrate benzylguanine (BG). Immobilizing sufficient amounts of BG on cellular membranes is a mean to enable cell-cell pairing as demonstrated by the covalent aggregation of microbeads carrying SNAP-tag and BG at high concentrations. The artificial niche models developed in this study are broadly applicable to desired cellular systems. These approaches help to gain insight into the multifactorial composition and architectural organization of specific niches and to enable their reconstruction in vitro

    Partizipative Gestaltung eines gebrauchstauglichen mobilen Assistenzsystems für Instandhalter

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    Mit dem Einsatz mobiler Produktionsassistenzsysteme entstehen neue Anforderungen an die Gestaltung von Mensch-Maschine-Schnittstellen (MMS). Solche MMS umfassen eine grafische Benutzerschnittstelle über die Softwareoberfläche (GUI) sowie eine tangible Mensch-Maschine-Schnittstelle (tMMS) über hardwaretechnische Funktions- und Bedienelemente. Eine gebrauchstaugliche Gestaltung dieser MMS liefert ein großes Potenzial zur sicheren Bedienung und steigert deren Akzeptanz durch die Anwender. Aufbauend auf den Methoden des Usability Engineering wird die nutzerzentrierte Entwicklung einer gebrauchstauglichen MMS für das Ressourcencockpit Phasen dargestellt. Grundlage hierfür bietet ein Anforderungskatalog, der die Bedarfe von Instandhaltern, Service-Technikern sowie Planungs- und Instandhaltungsleitern zusammenfasst. Auch bei der iterativen Entwicklung, Prototypengestaltung und Evaluation wird eine partizipative Vorgehensweise gemeinsam mit den Anwendern gewählt. Im Ergebnis liegen für Teilaspekte der Gestaltung und den zusammengesetzten Geometrieprototypen bereits hohe Bewertungen der Gebrauchstauglichkeit vor

    An overview of the taxonomy, phylogeny, and typification of nectriaceous fungi in Cosmospora, Acremonium, Fusarium, Stilbella, and Volutella

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    A comprehensive phylogenetic reassessment of the ascomycete genus Cosmospora (Hypocreales, Nectriaceae) is undertaken using fresh isolates and historical strains, sequences of two protein encoding genes, the second largest subunit of RNA polymerase II (rpb2), and a new phylogenetic marker, the larger subunit of ATP citrate lyase (acl1). The result is an extensive revision of taxonomic concepts, typification, and nomenclatural details of many anamorph- and teleomorph-typified genera of the Nectriaceae, most notably Cosmospora and Fusarium. The combined phylogenetic analysis shows that the present concept of Fusarium is not monophyletic and that the genus divides into two large groups, one basal in the family, the other terminal, separated by a large group of species classified in genera such as Calonectria, Neonectria, and Volutella. All accepted genera received high statistical support in the phylogenetic analyses. Preliminary polythetic morphological descriptions are presented for each genus, providing details of perithecia, micro- and/or macro-conidial synanamorphs, cultural characters, and ecological traits. Eight species are included in our restricted concept of Cosmospora, two of which have previously documented teleomorphs and all of which have Acremonium-like microconidial anamorphs. A key is provided to the three anamorphic species recognised in Atractium, which is removed from synonymy with Fusarium and epitypified for two macroconidial synnematous species and one sporodochial species associated with waterlogged wood. Dialonectria is recognised as distinct from Cosmospora and two species with teleomorph, macroconidia and microconidia are accepted, including the new species D. ullevolea. Seven species, one with a known teleomorph, are classified in Fusicolla, formerly considered a synonym of Fusarium including members of the F. aquaeductuum and F. merismoides species complex, with several former varieties raised to species rank. Originally a section of Nectria, Macroconia is raised to generic rank for five species, all producing a teleomorph and macroconidial anamorph. A new species of the Verticillium-like anamorphic genus Mariannaea is described as M. samuelsii. Microcera is recognised as distinct from Fusarium and a key is included for four macroconidial species, that are usually parasites of scale insects, two of them with teleomorphs. The four accepted species of Stylonectria each produce a teleomorph and micro- and macroconidial synanamorphs. The Volutella species sampled fall into three clades. Pseudonectria is accepted for a perithecial and sporodochial species that occurs on Buxus. Volutella s. str. also includes perithecial and/or sporodochial species and is revised to include a synnematous species formerly included in Stilbella. The third Volutella-like clade remains unnamed. All fungi in this paper are named using a single name system that gives priority to the oldest generic names and species epithets, irrespective of whether they are originally based on anamorph or teleomorph structures. The rationale behind this is discussed

    A convolute diversity of the Auriculariales (Agaricomycetes, Basidiomycota) with sphaeropedunculate basidia

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    Morphological and DNA data show that effused representatives of the Auriculariales (Basidiomycota) with sphaeropedunculate basidia belong to eleven genera of which seven are dealt with in this study. Among them, Myxarium is the largest genus containing 21 accepted species of which nine are reintroduced below and five are described as new. Protodontia is limited to three species only, P. subgelatinosa (the generic type) and two newly described species from Africa. Protoacia is a new monotypic genus for P. delicata, sp. nov., widely distributed on coniferous hosts in Eurasia. Myxariellum is erected for two new species with smooth hymenophore from northwestern North America while Gelacantha is introduced for G. pura, a new species with hydnoid hymenophore from Caucasus. Our data do not confirm the present synonymy of Sebacina sphaerospora with Tremella glaira, and these species are placed in two separate genera - Hydrophana, gen. nov., and Ofella, gen. nov., respectively. A key to European Myxarium and similar-looking species is included.Peer reviewe

    A systematic account of the genus Plagiostoma (Gnomoniaceae, Diaporthales) based on morphology, host-associations, and a four-gene phylogeny

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    Members of the genus Plagiostoma inhabit leaves, stems, twigs, and branches of woody and herbaceous plants predominantly in the temperate Northern Hemisphere. An account of all known species of Plagiostoma including Cryptodiaporthe is presented based on analyses of morphological, cultural, and DNA sequence data. Multigene phylogenetic analyses of DNA sequences from four genes (β-tubulin, ITS, rpb2, and tef1-α) revealed eight previously undescribed phylogenetic species and an association between a clade composed of 11 species of Plagiostoma and the host family Salicaceae. In this paper these eight new species of Plagiostoma are described, four species are redescribed, and four new combinations are proposed. A key to the 25 accepted species of Plagiostoma based on host, shape, and size of perithecia, perithecial arrangement in the host, and microscopic characteristics of the asci and ascospores is provided. Disposition of additional names in Cryptodiaporthe and Plagiostoma is also discussed

    Molecular phylogenetics of Pleosporales: Melanommataceae and Lophiostomataceae re-circumscribed (Pleosporomycetidae, Dothideomycetes, Ascomycota)

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    The classification of Pleosporales has posed major challenges due to the lack of clear understanding of the importance of the morphological characters used to distinguish between different groups in the order. This has resulted in varied taxonomic treatments of many families in the group including Melanommataceae and Lophiostomataceae. In this study we employ two nuclear DNA gene markers, nuclear ribosomal large subunit DNA and translation elongation factor 1-alpha in order to examine the molecular phylogenetics of Pleosporales with strong emphasis on the families Melanommataceae and Lophiostomataceae. Phylogenetic analyses recovered Melanommataceae, Lophiostomataceae, Hypsostromataceae, and a few others as strongly supported clades within the Pleosporales. Melanommataceae as currently circumscribed was found to be polyphyletic. The genera Byssosphaeria, Melanomma, and Pseudotrichia were recovered within the family, while others such as Ostropella and Xenolophium nested outside in a weakly supported group along with Platystomum compressum and Pseudotrichia guatopoensis that may correspond to the family Platystomaceae. The genus Byssosphaeria was recovered as a strongly supported group within the Melanommataceae while Melanomma was weakly supported with unclear relationships among the species. The genera Herpotrichia and Bertiella were also found to belong in the Melanommataceae. Lophiostomataceae occurs as a strongly supported group but its concept is here expanded to include a new genus Misturatosphaeria that bears morphology traditionally not known to occur in the family. The strongly supported clade of Misturatosphaeria contains nine species that have gregarious, papillate ascomata with lighter coloured apices and plugged ostioles and that vary in ascospore morphology from 1- to 3-septate to muriform. Along with a strongly supported Lophiostoma clade, also within the family are Thyridaria macrostomoides based on new sequences from Kenyan collections and Massariosphaeria triseptata, M. grandispora, Westerdykella cylindrica and Preussia terricola based on GenBank sequences. The family Hypsostromataceae was recovered as a strongly supported monophyletic group nested within the Pleosporales

    Pleosporales

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    One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae

    Leaf-inhabiting genera of the Gnomoniaceae, Diaporthales

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    The Gnomoniaceae are characterised by ascomata that are generally immersed, solitary, without a stroma, or aggregated with a rudimentary stroma, in herbaceous plant material especially in leaves, twigs or stems, but also in bark or wood. The ascomata are black, soft-textured, thin-walled, and pseudoparenchymatous with one or more central or eccentric necks. The asci usually have a distinct apical ring. The Gnomoniaceae includes species having ascospores that are small, mostly less than 25 μm long, although some are longer, and range in septation from non-septate to one-septate, rarely multi-septate. Molecular studies of the Gnomoniaceae suggest that the traditional classification of genera based on characteristics of the ascomata such as position of the neck and ascospores such as septation have resulted in genera that are not monophyletic. In this paper the concepts of the leaf-inhabiting genera in the Gnomoniaceae are reevaluated using multiple genes, specifically nrLSU, translation elongation factor 1-alpha (tef1-α), and RNA polymerase II second largest subunit (rpb2) for 64 isolates. ITS sequences were generated for 322 isolates. Six genera of leaf-inhabiting Gnomoniaceae are defined based on placement of their type species within the multigene phylogeny. The new monotypic genus Ambarignomonia is established for an unusual species, A. petiolorum. A key to 59 species of leaf-inhabiting Gnomoniaceae is presented and 22 species of Gnomoniaceae are described and illustrated
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