45 research outputs found

    Molecular dynamics description of an expanding qq/qˉ\bar{q} plasma with the Nambu--Jona-Lasinio model and applications to heavy ion collisions at RHIC and LHC energies

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    We present a relativistic molecular dynamics approach based on the Nambu--Jona-Lasinio Lagrangian. We derive the relativistic time evolution equations for an expanding plasma, discuss the hadronization cross section and how they act in such a scenario. We present in detail how one can transform the time evolution equation to a simulation program and apply this program to study the expansion of a plasma created in experiments at RHIC and LHC. We present first results on the centrality dependence of v2v_2 and of the transverse momentum spectra of pions and kaons and discuss in detail the hadronisation mechanism.Comment: 25 pages, 28 figure

    Gating Kinetics of Single Large-Conductance Ca2+-Activated K+ Channels in High Ca2+ Suggest a Two-Tiered Allosteric Gating Mechanism✪

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    The Ca2+-dependent gating mechanism of large-conductance calcium-activated K+ (BK) channels from cultured rat skeletal muscle was examined from low (4 μM) to high (1,024 μM) intracellular concentrations of calcium (Ca2+i) using single-channel recording. Open probability (Po) increased with increasing Ca2+i (K0.5 11.2 ± 0.3 μM at +30 mV, Hill coefficient of 3.5 ± 0.3), reaching a maximum of ∼0.97 for Ca2+i ∼ 100 μM. Increasing Ca2+i further to 1,024 μM had little additional effect on either Po or the single-channel kinetics. The channels gated among at least three to four open and four to five closed states at high levels of Ca2+i (>100 μM), compared with three to four open and five to seven closed states at lower Ca2+i. The ability of kinetic schemes to account for the single-channel kinetics was examined with simultaneous maximum likelihood fitting of two-dimensional (2-D) dwell-time distributions obtained from low to high Ca2+i. Kinetic schemes drawn from the 10-state Monod-Wyman-Changeux model could not describe the dwell-time distributions from low to high Ca2+i. Kinetic schemes drawn from Eigen's general model for a ligand-activated tetrameric protein could approximate the dwell-time distributions but not the dependency (correlations) between adjacent intervals at high Ca2+i. However, models drawn from a general 50 state two-tiered scheme, in which there were 25 closed states on the upper tier and 25 open states on the lower tier, could approximate both the dwell-time distributions and the dependency from low to high Ca2+i. In the two-tiered model, the BK channel can open directly from each closed state, and a minimum of five open and five closed states are available for gating at any given Ca2+i. A model that assumed that the apparent Ca2+-binding steps can reach a maximum rate at high Ca2+i could also approximate the gating from low to high Ca2+i. The considered models can serve as working hypotheses for the gating of BK channels

    Don\u27t Let It Happen Again

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    https://digitalcommons.library.umaine.edu/mmb-vp-copyright/5084/thumbnail.jp

    Transport coefficients from the Nambu-Jona-Lasinio model for SU(3)fSU(3)_f

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    13 pages, 16 figuresWe calculate the shear η(T)\eta(T) and bulk viscosities ζ(T)\zeta(T) as well as the electric conductivity σe(T)\sigma_e(T) and heat conductivity κ(T)\kappa(T) within the Nambu-Jona-Lasinio model for 3 flavors as a function of temperature as well as the entropy density s(T)s(T), pressure P(T)P(T) and speed of sound cs2(T)c_s^2(T). We compare the results with other models such as the Polyakov-Nambu-Jona-Lasinio (PNJL) model and the dynamical quasiparticle model (DQPM) and confront these results with lattice QCD data whenever available. We find the NJL model to have a limited predictive power for the thermodynamic variables and various transport coefficients above the critical temperature whereas the PNJL model and DQPM show acceptable results for the quantities of interest

    Design of the ocular coil, a new device for non-invasive drug delivery

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    \u3cp\u3eEye drops and ointments are the most prescribed methods for ocular drug delivery. However, due to low drug bioavailability, rapid drug elimination, and low patient compliance there is a need for improved ophthalmic drug delivery systems. This study provides insights into the design of a new drug delivery device that consists of an ocular coil filled with ketorolac loaded PMMA microspheres. Nine different ocular coils were created, ranging in wire diameter and coiled outer diameter. Based on its microsphere holding capacity and flexibility, one type of ocular coil was selected and used for further experiments. No escape of microspheres was observed after bending the ocular coil at curvature which reflect the in vivo situation in human upon positioning in the lower conjunctival sac. Shape behavior and tissue contact were investigated by computed tomography imaging after inserting the ocular coil in the lower conjunctival fornix of a human cadaver. Thanks to its high flexibility, the ocular coil bends along the circumference of the eye. Because of its location deep in the fornix, it appears unlikely that in vivo, the ocular coil will interfere with eye movements. In vitro drug release experiments demonstrate the potential of the ocular coil as sustained drug delivery device for the eye. We developed PMMA microspheres with a 26.5 ± 0.3 wt% ketorolac encapsulation efficiency. After 28 days, 69.9% ± 5.6% of the loaded ketorolac was released from the ocular coil when tested in an in vitro lacrimal system. In the first three days high released dose (48.7% ± 5.4%) was observed, followed by a more gradually release of ketorolac. Hence, the ocular coil seems a promising carrier for ophthalmic drugs delivery in the early postoperative time period.\u3c/p\u3

    Design of the ocular coil, a new device for non-invasive drug delivery

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    Eye drops and ointments are the most prescribed methods for ocular drug delivery. However, due to low drug bioavailability, rapid drug elimination, and low patient compliance there is a need for improved ophthalmic drug delivery systems. This study provides insights into the design of a new drug delivery device that consists of an ocular coil filled with ketorolac loaded PMMA microspheres. Nine different ocular coils were created, ranging in wire diameter and coiled outer diameter. Based on its microsphere holding capacity and flexibility, one type of ocular coil was selected and used for further experiments. No escape of microspheres was observed after bending the ocular coil at curvature which reflect the in vivo situation in human upon positioning in the lower conjunctival sac. Shape behavior and tissue contact were investigated by computed tomography imaging after inserting the ocular coil in the lower conjunctival fornix of a human cadaver. Thanks to its high flexibility, the ocular coil bends along the circumference of the eye. Because of its location deep in the fornix, it appears unlikely that in vivo, the ocular coil will interfere with eye movements. In vitro drug release experiments demonstrate the potential of the ocular coil as sustained drug delivery device for the eye. We developed PMMA microspheres with a 26.5 ± 0.3 wt% ketorolac encapsulation efficiency. After 28 days, 69.9% ± 5.6% of the loaded ketorolac was released from the ocular coil when tested in an in vitro lacrimal system. In the first three days high released dose (48.7% ± 5.4%) was observed, followed by a more gradually release of ketorolac. Hence, the ocular coil seems a promising carrier for ophthalmic drugs delivery in the early postoperative time period

    Design of the ocular coil, a new device for non-invasive drug delivery

    No full text
    Eye drops and ointments are the most prescribed methods for ocular drug delivery. However, due to low drug bioavailability, rapid drug elimination, and low patient compliance there is a need for improved ophthalmic drug delivery systems. This study provides insights into the design of a new drug delivery device that consists of an ocular coil filled with ketorolac loaded PMMA microspheres. Nine different ocular coils were created, ranging in wire diameter and coiled outer diameter. Based on its microsphere holding capacity and flexibility, one type of ocular coil was selected and used for further experiments. No escape of microspheres was observed after bending the ocular coil at curvature which reflect the in vivo situation in human upon positioning in the lower conjunctival sac. Shape behavior and tissue contact were investigated by computed tomography imaging after inserting the ocular coil in the lower conjunctival fornix of a human cadaver. Thanks to its high flexibility, the ocular coil bends along the circumference of the eye. Because of its location deep in the fornix, it appears unlikely that in vivo, the ocular coil will interfere with eye movements. In vitro drug release experiments demonstrate the potential of the ocular coil as sustained drug delivery device for the eye. We developed PMMA microspheres with a 26.5 +/- 0.3 wt% ketorolac encapsulation efficiency. After 28 days, 69.9% +/- 5.6% of the loaded ketorolac was released from the ocular coil when tested in an in vitro lacrimal system. In the first three days high released dose (48.7% +/- 5.4%) was observed, followed by a more gradually release of ketorolac. Hence, the ocular coil seems a promising carrier for ophthalmic drugs delivery in the early postoperative time period
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