Mixing and condensation in a wet granular medium

We have studied the effect of small amounts of added liquid on the dynamic behavior of a granular system consisting of a mixture of glass beads of two different sizes. Segregation of the large beads to the top of the sample is found to depend in a nontrivial way on the liquid content. A transition to viscoplastic behavior occurs at a critical liquid content, which depends upon the bead size. We show that this transition can be interpreted as a condensation due to the hysteretic liquid bridge forces connecting the beads, and provide the corresponding phase diagram.Comment: submitted to PR

Dynamik feuchter Granulate

Gegenstand der vorliegenden Dissertation ist die experimentelle Untersuchung der dynamischen Aspekte eines feuchten Granulats. Das erste Kapitel behandelt dabei die Dynamik einer Flüssigkeit in einem Granulat. Die sich hierbei einstellenden Flüssigkeitsstrukturen sind unter anderem für die Dynamik der Partikel von wesentlicher Bedeutung. Diese Partikel-Dynamik wird im zweiten Kapitel besprochen. Dabei wird zunächst auf die Scherfestigkeit eines feuchten Granulats eingegangen und anschließend auf die Fluidisierung sowie die Segregation

Nonlocal Dynamics of Spontaneous Imbibition Fronts

We have studied spontaneous imbibition fronts generated by capillary rise between two roughened glass plates, the separation d of which varied between 10 and 50¿¿¿¿m. Perfect agreement with Washburn¿s law was obtained. We have determined the roughness exponent ¿ of the fronts, and found ¿=0.81±0.01 for small length scales. Above a certain crossover length ¿, it reached ¿=0.58±0.04, as predicted by the quenched noise Kardar-Parisi-Zhang equation. The crossover length is found to scale with the plate separation as sqrt[d], as predicted by recent models which properly include nonlocal dynamics effects on the front. We believe this to be the first clear identification of crossover from nonlocal to local dynamics

Mixing and Condensation in a Wet Granular Medium

Some experiments were recently done on the influence of liquid on the mixing behavior of systems consisting of large and small spheres. It was observed that as liquid was added, the tendency to segregate, which was well known for dry granulates, was diminished. In these experiments the morphology of heaps formed by pouring mixtures of particles with two different sizes through an orifice was investigated. In order to have a closer look at the observed effects, experiments were carried out in which the agitation of the material was provided in a more homogeneous way, thus ensuring a more or less well defined granular temperature

Saffron as a Source of Novel Acetylcholinesterase Inhibitors: Molecular Docking and in Vitro Enzymatic Studies

Inhibitors of acetylcholine breakdown by acetylcholinesterase (AChE) constitute the main therapeutic modality for Alzheimer’s disease. In the search for natural products with inhibitory action on AChE, this study investigated the activity of saffron extract and its constituents by in vitro enzymatic and molecular docking studies. Saffron has been used in traditional medicine against Alzheimer’s disease. Saffron extract showed moderate AChE inhibitory activity (up to 30%), but IC₅₀ values of crocetin, dimethylcrocetin, and safranal were 96.33, 107.1, and 21.09 μM, respectively. Kinetic analysis showed mixed-type inhibition, which was verified by in silico docking studies. Safranal interacts only with the binding site of the AChE, but crocetin and dimethylcrocetin bind simultaneously to the catalytic and peripheral anionic sites. These results reinforce previous findings about the beneficial action of saffron against Alzheimer’s disease and may be of value for the development of novel therapeutic agents based on carotenoid-based dual binding inhibitors