Genetically Encoded Calcium Indicators: A New Tool in Renal Hypertension Research

Hypertension is ranked as the third cause of disability-adjusted life-years. The percentage of the population suffering from hypertension will continue to increase over the next years. Renovascular disease is one of the most common causes of secondary hypertension. Vascular changes seen in hypertension are partially based on dysfunctional calcium signaling. This signaling can be studied using calcium indicators (loading dyes and genetically encoded calcium indicators; GECIs). Most progress in development has been seen in GECIs, which are used in an increasing number of publications concerning calcium signaling in vasculature and the kidney. The use of transgenic mouse models expressing GECIs will facilitate new possibilities to study dysfunctional calcium signaling in a cell type-specific manner, thus helping to identify more specific targets for treatment of (renal) hypertension

The virial relation for the Q-balls in the thermal logarithmic potential revisited analytically

We study the properties of Q-balls dominated by the thermal logarithmic potential analytically instead of estimating the characters with only some specific values of model variables numerically. In particular the analytical expressions for radius and energy of this kind of Q-ball are obtained. According to these explicit expressions we demonstrate strictly that the large Q-balls enlarge and the small ones become smaller in the background with lower temperature. The energy per unit charge will not be divergent if the charge is enormous. We find that the lower temperature will lead the energy per unit charge of Q-ball smaller. We also prove rigorously the necessary conditions that the model parameters should satisfy to keep the stability of the Q-balls. When one of model parameters of Q-balls $K$ is positive, the Q-balls will not form or survive unless the temperature is high enough. In the case of negative $K$, the Q-balls are stable no matter the temperature is high or low.Comment: 12 pages, 2 figure

Simplified topological invariants for interacting insulators

We propose general topological order parameters for interacting insulators in terms of the Green's function at zero frequency. They provide an unified description of various interacting topological insulators including the quantum anomalous Hall insulators and the time reversal invariant insulators in four, three and two dimensions. Since only Green's function at zero frequency is used, these topological order parameters can be evaluated efficiently by most numerical and analytical algorithms for strongly interacting systems.Comment: Published versio

A Pedagogical Discussion on Neutrino Wave-Packet Evolution

We present a pedagogical discussion on the time evolution of a Gaussian neutrino wave packet in free space. A common treatment is to keep momentum terms up to the quadratic order in the expansion of the energy-momentum relation so that the Fourier transform can be evaluated analytically via Gaussian integrals. This leads to a solution representing a flat Gaussian distribution with a constant longitudinal width and a spreading transverse width, which suggests that special relativity would be violated if the neutrino wave packet were detected on its edge. However, we demonstrate that by including terms of higher order in momentum the correct geometry of the wave packet is restored. The corrected solution has a spherical wave front so that it complies with special relativity.Comment: submitted to 2013 TAUP Conference Proceeding

Nucleation of membrane adhesions

Recent experimental and theoretical studies of biomimetic membrane adhesions [Bruinsma et al., Phys. Rev. E 61, 4253 (2000); Boulbitch et al., Biophys. J. 81, 2743 (2001)] suggested that adhesion mediated by receptor interactions is due to the interplay between membrane undulations and a double-well adhesion potential, and should be a first-order transition. We study the nucleation of membrane adhesion by finding the minimum-energy path on the free energy surface constructed from the bending free energy of the membrane and the double-well adhesion potential. We find a nucleation free energy barrier around 20kBT for adhesion of flexible membranes, which corresponds to fast nucleation kinetics with a time scale of the order of seconds. For cell membranes with a larger bending rigidity due to the actin network, the nucleation barrier is higher and may require active processes such as the reorganization of the cortex network to overcome this barrier. Our scaling analysis suggests that the geometry of the membrane shapes of the adhesion contact is controlled by the adhesion length that is determined by the membrane rigidity, the barrier height, and the length scale of the double-well potential, while the energetics of adhesion is determined by the depths of the adhesion potential. These results are verified by numerical calculations

On potential maximization as a refinement of Nash equilibrium

We specify an adjustment process that converges to the set of potential-maximizing strategy profiles for 3-player cooperation-formation games or n-player cooperation-formation games based on a superadditive characteristic function. Our analysis provides a justification for potential maximization as a refinement of Nash equilibrium in these settings.adjustment process.