Mutual Mobile Membranes with Timers

A feature of current membrane systems is the fact that objects and membranes are persistent. However, this is not true in the real world. In fact, cells and intracellular proteins have a well-defined lifetime. Inspired from these biological facts, we define a model of systems of mobile membranes in which each membrane and each object has a timer representing their lifetime. We show that systems of mutual mobile membranes with and without timers have the same computational power. An encoding of timed safe mobile ambients into systems of mutual mobile membranes with timers offers a relationship between two formalisms used in describing biological systems

Aging dynamics in interacting many-body systems

Low-dimensional, complex systems are often characterized by logarithmically slow dynamics. We study the generic motion of a labeled particle in an ensemble of identical diffusing particles with hardcore interactions in a strongly disordered, one-dimensional environment. Each particle in this single file is trapped for a random waiting time $\tau$ with power law distribution $\psi(\tau)\simeq\tau^{-1- \alpha}$, such that the $\tau$ values are independent, local quantities for all particles. From scaling arguments and simulations, we find that for the scale-free waiting time case $0<\alpha<1$, the tracer particle dynamics is ultra-slow with a logarithmic mean square displacement (MSD) $\langle x^2(t)\rangle\simeq(\log t)^{1/2}$. This extreme slowing down compared to regular single file motion $\langle x^2(t)\rangle\simeq t^{1/2}$ is due to the high likelihood that the labeled particle keeps encountering strongly immobilized neighbors. For the case $1<\alpha<2$ we observe the MSD scaling $\langle x^2(t)\rangle\simeq t^{\gamma}$, where $\gamma2$ we recover Harris law $\simeq t^{1/2}$.Comment: 5 pages, 4 figure

Data collection system: Earth Resources Technology Satellite-1

Subjects covered at the meeting concerned results on the overall data collection system including sensors, interface hardware, power supplies, environmental enclosures, data transmission, processing and distribution, maintenance and integration in resources management systems

The Biosurfactant β-Aescin: A Review on the Physico-Chemical Properties and Its Interaction with Lipid Model Membranes and Langmuir Monolayers

Geisler R, Dargel C, Hellweg T. The Biosurfactant β-Aescin: A Review on the Physico-Chemical Properties and Its Interaction with Lipid Model Membranes and Langmuir Monolayers. Molecules. 2020;25(1): 117.This review discusses recent progress in physicochemical understanding of the action of the saponin β -aescin (also called β -escin), the biologically active component in the seeds of the horse chestnut tree Aesculus hippocastanum. β -Aescin is used in pharmacological and cosmetic applications showing strong surface activity. In this review, we outline the most important findings describing the behavior of β -aescin in solution (e.g., critical micelle concentration ( cmc ) and micelle shape) and special physicochemical properties of adsorbed β -aescin monolayers at the air–water and oil–water interface. Such monolayers were found to posses very special viscoelastic properties. The presentation of the experimental findings is complemented by discussing recent molecular dynamics simulations. These simulations do not only quantify the predominant interactions in adsorbed monolayers but also highlight the different behavior of neutral and ionized β -aescin molecules. The review concludes on the interaction of β -aescin with phospholipid model membranes in the form of bilayers and Langmuir monolayers. The interaction of β -aescin with lipid bilayers was found to strongly depend on its cmc . At concentrations below the cmc , membrane parameters are modified whereas above the cmc , complete solubilization of the bilayers occurs, depending on lipid phase state and concentration. In the presence of gel-phase phospholipids, discoidal bicelles form; these are tunable in size by composition. The phase behavior of β -aescin with lipid membranes can also be modified by addition of other molecules such as cholesterol or drug molecules. The lipid phase state also determines the penetration rate of β -aescin molecules into lipid monolayers. The strongest interaction was always found in the presence of gel-phase phospholipid molecules

The Ursinus Weekly, January 21, 1970

USGA plans to improve communications at Ursinus • Modified curriculum announced • Dr. Sachar discusses dissenters • Board of Directors increases tuition • Premed meeting • Free learning • Editorial: Tuition increase • Focus: Kim Brown • Faculty portrait: Dr. Conrad Kruse • Tiny time pills • Letters to the editor: Moratorium; Football congrats; Red neck • Administration answers • Sexton\u27s kind • Perspectives: On priorities • Ursinus pulverizes Diplomats by 76-56 for fifth triumph • Videon\u27s matmen fall to Albright • Final examination schedulehttps://digitalcommons.ursinus.edu/weekly/1154/thumbnail.jp