81 research outputs found

    A Third Measure-Metastable State in the Dynamics of Spontaneous Shape Change in Healthy Human's White Cells

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    Human polymorphonuclear leucocytes, PMN, are highly motile cells with average 12-15 ”m diameters and prominent, loboid nuclei. They are produced in the bone marrow, are essential for host defense, and are the most populous of white blood cell types. PMN also participate in acute and chronic inflammatory processes, in the regulation of the immune response, in angiogenesis, and interact with tumors. To accommodate these varied functions, their behavior is adaptive, but still definable in terms of a set of behavioral states. PMN morphodynamics have generally involved a non-equilibrium stationary, spheroid Idling state that transitions to an activated, ellipsoid translocating state in response to chemical signals. These two behavioral shape-states, spheroid and ellipsoid, are generally recognized as making up the vocabulary of a healthy PMN. A third, “random” state has occasionally been reported as associated with disease states. I have observed this third, Treadmilling state, in PMN from healthy subjects, the cells demonstrating metastable dynamical behaviors known to anticipate phase transitions in mathematical, physical, and biological systems. For this study, human PMN were microscopically imaged and analyzed as single living cells. I used a microscope with a novel high aperture, cardioid annular condenser with better than 100 nanometer resolution of simultaneous, mixed dark field and intrinsic fluorescent images to record shape changes in 189 living PMNs. Relative radial roundness, R(t), served as a computable order parameter. Comparison of R(t) series of 10 cells in the Idling and 10 in the Treadmilling state reveals the robustness of the “random” appearing Treadmilling state, and the emergence of behaviors observed in the neighborhood of global state transitions, including increased correlation length and variance (divergence), sudden jumps, mixed phases, bimodality, power spectral scaling and temporal slowing. Wavelet transformation of an R(t) series of an Idling to Treadmilling state change, demonstrated behaviors concomitant with the observed transition

    Quantitative analysis by renormalized entropy of invasive electroencephalograph recordings in focal epilepsy

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    Invasive electroencephalograph (EEG) recordings of ten patients suffering from focal epilepsy were analyzed using the method of renormalized entropy. Introduced as a complexity measure for the different regimes of a dynamical system, the feature was tested here for its spatio-temporal behavior in epileptic seizures. In all patients a decrease of renormalized entropy within the ictal phase of seizure was found. Furthermore, the strength of this decrease is monotonically related to the distance of the recording location to the focus. The results suggest that the method of renormalized entropy is a useful procedure for clinical applications like seizure detection and localization of epileptic foci.Comment: 10 pages, 5 figure

    Combined effects of franchise management strategies and employee service performance on customer loyalty: a multilevel perspective

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    Although franchisee performance is likely to be influenced by franchisors’ management strategies, little is known about whether and how franchisors’ strategies affect franchisee employees’ performance. This study examines the combined effects of three franchisor management strategies, namely innovative culture, support services and autonomy on service performance of the franchisee store employees and the loyalty of their customers. Data were collected from a total of 38 employees and 679 customers of 25 franchisee stores. The study employs multilevel analysis on a nested data-set created by matching customer data with employee data for each store. The results reveal that customer loyalty of a franchisee store is positively influenced by the service performance of its employees and the support services received by the employees of the store from its franchisor. On the other hand, it has been found that franchisor management strategy such as innovative culture and autonomy negatively influence customer loyalty of the franchisee store. The paper discusses relevant theoretical and managerial implications of the findings

    PROTDES: CHARMM toolbox for computational protein design

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    We present an open-source software able to automatically mutate any residue positions and find the best aminoacids in an arbitrary protein structure without requiring pairwise approximations. Our software, PROTDES, is based on CHARMM and it searches automatically for mutations optimizing a protein folding free energy. PROTDES allows the integration of molecular dynamics within the protein design. We have implemented an heuristic optimization algorithm that iteratively searches the best aminoacids and their conformations for an arbitrary set of positions within a structure. Our software allows CHARMM users to perform protein design calculations and to create their own procedures for protein design using their own energy functions. We show this by implementing three different energy functions based on different solvent treatments: surface area accessibility, generalized Born using molecular volume and an effective energy function. PROTDES, a tutorial, parameter sets, configuration tools and examples are freely available at http://soft.synth-bio.org/protdes.html

    Is Dopamine a Physiological Natriuretic Hormone in the Dog?

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