Publications by authors named "Christopher Rosin"

Data is essential to governing those emerging matters of concern that confront the agrifood every day. But data is no neutral intermediary. It disrupts, exposes, and creates new social, economic, political, and environmental possibilities, whilst simultaneously hiding, excluding, and foreclosing others.

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Outcome of patients with blood stream infections (BSI) depends on the rapid initiation of adequate antibiotic therapy, which relies on the fast and reliable identification of the underlying pathogen. Blood cultures (BC) using CO-sensitive colorimetric indicators and subsequent microbiological culturing are the diagnostic gold standard but turnaround times range between 24 and 48 h. The detection of volatile organic compounds of microbial origin (mVOC) has been described as a feasible method for identifying microbial growth and to differentiate between several microbial species.

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Actin and tubulin, the main components of the cytoskeleton, are responsible for many different cellular functions and can be found in nearly all eukaryotic cells. The formation of filamentous actin (F-actin) as well as microtubules depends strongly on environmental and solution conditions. The self-assembly of both, actin and tubulin, has been found to be among the most pressure sensitive process in vivo.

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Biophysics under extreme conditions is the fundamental platform for scrutinizing life in unusual habitats, such as those in the deep sea or continental subsurfaces, but also for putative extraterrestrial organisms. Therefore, an important thermodynamic variable to explore is pressure. It is shown that the combination of infrared spectroscopy with simulation is an exquisite approach for unraveling the intricate pressure response of the solvation pattern of TMAO in water, which is expected to be transferable to biomolecules in their native solvent.

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Membrane type 1-matrix metalloproteinase (MT1-MMP or MMP-14) is a zinc-transmembrane metalloprotease involved in the degradation of extracellular matrix and tumor invasion. While changes in solvation of MT1-MMP have been recently studied, little is known about the structural and energetic changes associated with MT1-MMP while interacting with substrates. Steady-state kinetic and thermodynamic data (including activation energies and activation volumes) were measured over a wide range of temperatures and pressures by means of a stopped-flow fluorescence technique.

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Not only drastic temperature- but also pressure-induced perturbations of membrane organization pose a serious challenge to the biological cell. Although high hydrostatic pressure significantly influences the structural properties and thus functional characteristics of cells, this has not prevented life from invading the high pressure habitats of marine depths where pressures up to the 100 MPa level are encountered. Here, the temperature- and pressure-dependent structure and phase behavior of giant plasma membrane vesicles have been explored in the absence and presence of membrane proteins using a combined spectroscopic and microscopic approach.

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In vivo studies have shown that the cytoskeleton of cells is very sensitive to changes in temperature and pressure. In particular, actin filaments get depolymerized when pressure is increased up to several hundred bars, conditions that are easily encountered in the deep sea. We quantitatively evaluate the effects of temperature, pressure, and osmolytes on the kinetics of the polymerization reaction of actin by high-pressure stopped-flow experiments in combination with fluorescence detection and an integrative stochastic simulation of the polymerization process.

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Actin is the main component of the microfilament system in eukaryotic cells and can be found in distinct morphological states. Global (G)-actin is able to assemble into highly organized, supramolecular cellular structures known as filamentous (F)-actin and bundled (B)-actin. To evaluate the structure and stability of G-, F-, and B-actin over a wide range of temperatures and pressures, we used Fourier transform infrared spectroscopy in combination with differential scanning and pressure perturbation calorimetry, small-angle x-ray scattering, laser confocal scanning microscopy, and transmission electron microscopy.

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A combined temperature- and pressure-dependent study was employed to reveal the conformational and free-energy landscape of phenylalanine transfer RNA (tRNA(Phe) ), a known model for RNA function, to elucidate the features that are essential in determining its stability. These studies also help explore its structural properties under extreme environmental conditions, such as low/high temperatures and high pressures. To this end, fluorescence and FTIR spectroscopies, calorimetric and small-angle scattering measurements were carried out at different ion concentrations over a wide range of temperatures and pressures up to several hundred MPa.

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We studied the effects of kosmotropic and chaotropic cosolvents, trimethylamine-N-oxide (TMAO) and urea, as well as crowding agents (dextran) on the polymerization reaction of actin. Time-lapse fluorescence intensity and anisotropy experiments were carried out to yield information about the kinetics of the polymerization process. To also quantitatively describe the effects, cosolvents and crowding impose on the underlying rate constants of the G-to-F-transformation, an integrative stochastic simulation model was applied.

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Game playing.

Wiley Interdiscip Rev Cogn Sci

March 2014

Game playing has been a core domain of artificial intelligence research since the beginnings of the field. Game playing provides clearly defined arenas within which computational approaches can be readily compared to human expertise through head-to-head competition and other benchmarks. Game playing research has identified several simple core algorithms that provide successful foundations, with development focused on the challenges of defeating human experts in specific games.

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The biomodification of surfaces, especially titanium, is an important issue in current biomedical research. Regarding titanium, it is also important to ensure a specific protein modification of its surface because here protein binding that is too random can be observed. Specific nanoscale architectures can be applied to overcome this problem.

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It is well-known that protein-modified implant surfaces such as TiO(2) show a higher bioconductivity. Fibronectin is a glycoprotein from the extracellular matrix (ECM) with a major role in cell adhesion. It can be applied on titanium oxide surfaces to accelerate implant integration.

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