64 research outputs found
Bulk sensitive photo emission spectroscopy of C1b compounds
This work reports about bulk-sensitive, high energy photoelectron
spectroscopy from the valence band of CoTiSb excited by photons from 1.2 to 5
keV energy. The high energy photoelectron spectra were taken at the KMC-1 high
energy beamline of BESSY II employing the recently developed Phoibos 225 HV
analyser. The measurements show a good agreement to calculations of the
electronic structure using the LDA scheme. It is shown that the high energy
spectra reveal the bulk electronic structure better compared to low energy XPS
spectra.Comment: J. Electron Spectrosc. Relat. Phenom. accepte
Local Photorelease of Caged Thymosin β4 in Locomoting Keratocytes Causes Cell Turning
The broad aim of this work was to explore the feasibility of using light-directed perturbation techniques to study cell locomotion. Specifically, a caged form of thymosin β4 (Tβ4) was photoactivated in a defined local region of locomoting fish scale keratocytes and the resulting perturbation of locomotion was studied. Purified Tβ4 was produced in an inactive form by “caging” with ([n-nitroveratryl]oxy)chlorocarbamate. In vitro spectrophotofluorometric assays indicated that caged Tβ4 did not change the normal actin polymerization kinetics, whereas photoactivated Tβ4 significantly inhibited actin polymerization. With an a priori knowledge of the cytoplasmic diffusion coefficient of Tβ4 as measured by fluorescence recovery after photobleaching experiments, the rapid sequestration of actin monomers by uncaged Tβ4 and the consequent reduction in the diffusional spread of the Tβ4–actin complex were predicted using Virtual Cell software (developed at the Center for Biomedical Imaging Technology, University of Connecticut Health Center). These simulations demonstrated that locally photoactivating Tβ4 in keratocytes could potentially elicit a regional locomotory response. Indeed, when caged Tβ4 was locally photoactivated at the wings of locomoting keratocytes, specific turning about the irradiated region was observed, whereas various controls were negative. Additionally, loading of exogenous Tβ4 into both keratocytes and fibroblasts caused very rapid disassembly of actin filaments and reduction of cellular contractility. Based on these results, a mechanical model is proposed for the turning behavior of keratocytes in response to photoreleased Tβ4
Mapping the absence : A theological critique of posthumanist influences in marketing and consumer research
In this study, we critically examine the ongoing adoption of various posthumanist influences into the fields of marketing and consumer research from a theological perspective. By conducting a theological-historical assessment, we propose that it is not posthuman notions of human/technology relations, nor their broader context in the emerging non-representational paradigms, that mark radically new disruptions in the continuing restructuring of the disciplines of marketing and consumer research. Instead, we argue that what is taking place is an implicit adherence to a contemporary form of age-old Christian dogma. As a radical conjecture, we thus propose that an identification of certain similarities between Christian dogma and the grounds for various posthumanist frameworks suggest that posthuman thought may well herald the global dissemination of a far more elusive, authoritarian, and hegemonic system than that which posthumanists typically claim to have abandoned. Consequently, we elaborate on implications to developments in marketing thought.Peer reviewe
SBML Level 3: an extensible format for the exchange and reuse of biological models
Systems biology has experienced dramatic growth in the number, size, and complexity of computational models. To reproduce simulation results and reuse models, researchers must exchange unambiguous model descriptions. We review the latest edition of the Systems Biology Markup Language (SBML), a format designed for this purpose. A community of modelers and software authors developed SBML Level 3 over the past decade. Its modular form consists of a core suited to representing reaction-based models and packages that extend the core with features suited to other model types including constraint-based models, reaction-diffusion models, logical network models, and rule-based models. The format leverages two decades of SBML and a rich software ecosystem that transformed how systems biologists build and interact with models. More recently, the rise of multiscale models of whole cells and organs, and new data sources such as single-cell measurements and live imaging, has precipitated new ways of integrating data with models. We provide our perspectives on the challenges presented by these developments and how SBML Level 3 provides the foundation needed to support this evolution
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