Abstract. Rockfall is an extremely rapid process involving long travel distances. Due to these features, when an event occurs, the ability to take evasive action is practically zero and, thus, the risk of injury or loss of life is high. Damage to buildings and infrastructure is quite likely. In many cases, therefore, suitable protection measures are necessary. This contribution provides an overview of previous and current research on the main topics related to rockfall. It covers the onset of rockfall and runout modelling approaches, as well as hazard zoning and protection measures. It is the aim of this article to provide an in-depth knowledge base for researchers and practitioners involved in projects dealing with the rockfall protection of infrastructures, who may work in the fields of civil or environmental engineering, risk and safety, the earth and natural sciences.

The aim of the paper is to develop a fully 3D simulation technique for rockfall dynamics taking rock shape into account and using the state-of-the-art methods of multibody dynamics and nonsmooth contact dynamics. The rockfall simulation technique is based on the nonsmooth contact dynamics method with hard contact laws. The rock is modeled as an arbitrary convex polyhedron and the terrain model is based on a high resolution digital elevation model. A specialized friction law for rockfall is proposed which allows for the description of scarring behavior (i.e., rocks tend to slide over the terrain before lift-off). The influence of rock geometry on rockfall dynamics is studied through two well-chosen numerical simulations.

Protection against natural hazards on windthrow areas We give an overview on natural hazard processes on windthrow areas during the first 20 years after the winterstorm Vivian (1990). This overview is based on 1) repeated pulling experiments and a long-term analysis of stem movements in the uncleared winthrow area Cavorgia/Disentis, 2) the assessment of avalanche protection function of 26 windthrow areas, and on (3) StorMe cadastral data of natural hazard events on windthrow areas. The effective heights and stem resistance of lying logs have been reduced to ca. 40% of the original values on average in the uncleared winthrow area Cavorgia/ Disentis. In particular on very steep (>45°) and rocky slopes, some of the stems have moved several meters. Most of the 26 investigated windthrow areas did not fulfill any of the considered criteria to effectively protect against avalanches. Nevertheless, very few avalanches and rockfall events were observed on Vivian areas. The relatively large number of shallow landslides in the years after the windthrow could, however, be a sign of a certain time with increased landslide susceptibility. Our results and observations suggest that the increased terrain roughness after Vivian largely compensated for the decreased protection effects against avalanche and rockfall of former stands structures during the first years after the storm. After 20 years, the terrain roughness effect has strongly decreased and reliable protection against mass movements depends in most cases on a sufficiently advanced natural forest regeneration or on additional post-windthrow plantations. It is important to consider specific conditions on the level of single slopes when planning measures against natural hazards in windthrow areas.

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Pharmaceutical excipients were designed originally to be pharmacologically inert. However, certain excipients were found to have altering effects on drug pharmacodynamics and/or pharmacokinetics. Pharmacokinetic interactions may be caused by modulation of efflux transporter proteins, intercellular tight junctions and/or metabolic enzyme amongst others. In this study, five disintegrants from different chemical classes were evaluated for P-glycoprotein (P-gp) related inhibition and tight junction modulation effects. Bi-directional transport studies of the model compound, Rhodamine 123 (R123) were conducted in the absence (control group) and presence (experimental groups) of four concentrations of each selected disintegrant across excised pig jejunum tissue. The results showed that some of the selected disintegrants (e.g. Ac-di-sol and Kollidon CL-M) increased R123 absorptive transport due to inhibition of P-gp related efflux, while another disintegrant (e.g. sodium alginate) changed R123 transport due to inhibition of P-gp in conjunction with a transient opening of the tight junctions in a concentration dependent way. It may be concluded that the co-application of some disintegrants to the intestinal epithelium may lead to pharmacokinetic interactions with drugs that are susceptible to P-gp related efflux. However, the clinical significance of these in vitro permeation findings should be confirmed by means of in vivo studies.

Simultaneous oral intake of herbs, supplements, foods and drugs with other drug(s) may result in pharmacokinetic or pharmacodynamic interactions with the latter. Although these interactions are often associated with unwanted effects such as adverse events or inefficacy, they can also produce effects that are potentially beneficial to the patient. Beneficial pharmacokinetic interactions include the improvement of the bioavailability of a drug (i.e., by enhancing absorption and/or inhibiting metabolism) or prolongation of a drug’s plasma level within its therapeutic window (i.e., by decreasing excretion), whereas beneficial pharmacodynamic interactions include additive or synergistic effects. Mechanisms by which pharmacokinetic interactions can cause beneficial effects include enhancement of membrane permeation (e.g., structural changes in the epithelial cell membranes or opening of tight junctions), modulation of carrier proteins (e.g., inhibition of efflux transporters and stimulation of uptake transporters) and inhibition of metabolic enzymes. In the current review, selected pharmacokinetic interactions between drugs and various compounds from different sources including food, herb, dietary supplements and selected drugs are discussed. These interactions may be exploited in the future to the benefit of the patient, for example, by delivering drugs that are poorly bioavailable in therapeutic levels via alternative routes of administration than parenteral injection.

Numerical simulations of rockfall trajectories are a standard procedure for evaluating rockfall hazards. For these simulations, corresponding software codes must be calibrated and evaluated based on field data. This study addresses methods of repeatable rockfall tests, and investigates whether it is possible to produce traceable and statistically analysable data. A testing series is described extensively covering how to conduct rockfall experiments and how certain elements of rockfall trajectories can be measured. The tests use acceleration and rotation sensors inside test blocks, a system to determine block positions over time, surveying measurements, and video recordings. All systems are evaluated regarding their usability in the field and for analyses. The highly detailed description of testing methods is the basis for sound understanding and reproducibility of the tests. This article serves as a reference for future publications and other rockfall field tests, both as a guide and as a basis for comparisons. First analyses deliver information on runout with a shadow angle ranging between 21 and 45 degrees for a slope consisting of homogeneous soft soil. A digital elevation model of the test site as well as point clouds of the used test blocks are part of this publication.