Three‐Dimensional Exploration and Mechano‐Biophysical Analysis of the Inner Structure of Living Cells

A novel mechanobiological method is presented to explore qualitatively and quantitatively the inside of living biological cells in three dimensions, paving the way to sense intracellular changes during dynamic cellular processes. For this purpose, holographic optical tweezers, which allow the versatile manipulation of nanoscopic and microscopic particles by means of tailored light fields, are combined with self‐interference digital holographic microscopy. This biophotonic holographic workstation enables non‐contact, minimally invasive, flexible, high‐precision optical manipulation and accurate 3D tracking of probe particles that are incorporated by phagocytosis in cells, while simultaneously quantitatively phase imaging the cell morphology. In a first model experiment, internalized polystyrene microspheres with 1 μm diameter are three‐dimensionally moved and tracked in order to quantify distances within the intracellular volume with submicrometer accuracy. Results from investigations on cell swelling provoked by osmotic stimulation demonstrate the homogeneous stretching of the cytoskeleton network, and thus that the proposed method provides a new way for the quantitative 3D analysis of the dynamic intracellular morphology.     

Experimental assessment of a blended fatigue-extreme controller employing trailing edge flaps

This paper presents an experimental assessment of a blended fatigue-extreme controller for load control employing trailing edge flaps on a lab-scale wind turbine. The controller blends between a repetitive model predictive controller that targets fatigue loads and a dedicated extreme load controller, which consists of a simple on-off load control strategy. The Fatigue controller uses the flapwise blade root bending moments of the three blades as input sensors. The Extreme controller additionally uses on-blade angle of attack and velocity measurements as well as acceleration measurements to detect extreme events and to allow for a fast reaction. The experiments are conducted on the Berlin Research Turbine within the large wind tunnel of the TU Berlin. In order to reproduce test cases with deterministic extreme wind conditions that follow industry standards, the wind tunnel was redesigned. The analyzed test cases are extreme direction change, extreme coherent gust, extreme operating gust and extreme coherent gust with direction change. The test cases are analyzed by on-blade angle of attack and velocity measurements. The load control performance of the Blended controller is compared to the pure fatigue oriented and the pure extreme load controller. The Blended controller achieves a maximum flapwise blade root bending moment reduction of 23%, which is comparable to the reduction achieved by the Extreme controller.     

Mikrobielle Werkstoffzerstörung – Simulation,Schadensfälle und Gegenmaßnahmen für anorganische nichtmetallische Werkstoffe: Biodeteriorationsprozesse an anorganischen Werkstoffen und mögliche Gegenmaßnahmen

Microbial deterioration of materials – simulation, case histories, and countermeasures for inorganic nonmetallic materials: Biodeterioration processes on inorganic materials and means of countermeasures Biodeterioration processes on inorganic materials such as natural stone, concrete, or glass can be subdivided into biogeochemical and biogeophysiological mechanisms according to their damage characteristics. In connection with the partial acidification and dissolving of components, biocorrosion as a result of biogenic release of inorganic and organic acids, as well as the biogenic oxidation of mineral forming cations, a certain weakening in the structure of the respective material can occur. The formation of biofilms on the surfaces of the inorganic materials impairs not only the aesthetical appearance of an object but also causes alterations in its humidity and temperature behaviour. In addition, due to the shrinking and swelling effects of biofilms, mechanical pressure to the mineral unit can occur (bioerosion, bioabrasion). Location and environmental factors which could lead to specific, biogenically determined weathering phenomena on these materials will be presented and elucidated. For controlling biodeterioration processes, the development and selection of environmentally-friendly, yet effective, inorganic and organic biocidal additives for stoneprotection agents as well as the use of gas (e.g. ethylene oxide) in their far-reaching significance for future material research will be presented here.     

Modellansätze zur langfristigen Entwicklung der Grundwasserqualität im Bourtanger Moor (Emsland)

Agricultural activities and atmospheric acid deposition are responsible for a significant decline of shallow groundwater quality in the Bourtanger Moor area near the German city Haren (Ems). The main indicators of acidification are low soil and groundwater pH and elevated aluminium concentrations. Agricultural nutrient concentrations, e. g. for potassium and nitrate commonly exceed drinking water limits. Polluted water has partially reached deeper layers where drinking water wells are screened. Contaminant spreading is retarded due to geochemical interactions with reactive aquifer material. Cation exchange and autotrophic denitrification are the main processes. Mass balance calculations, colums experiments and hydrogeochemical modelling show that the vertical propagation velocities of the contaminants are in the range of several centimetres per year.     

Experimental investigation of the reversible collapse of a capped amphiphile Langmuir monolayer

Surface isotherms, Brewster angle microscopy (BAM), surface potential measurements, and ab initio calculations were used to examine Langmuir monolayer films of an amphiphile with a bulky group that caps the terminus of an alkanol chain. BAM images of the collapsed state differ significantly from those of long-chain paraffinic amphiphiles. The collapsed phase BAM images show that aggregates of these amphiphiles extrude to form a three-dimensional phase. These clusters are able to easily reform the pre-collapse monolayer upon release of the applied surface pressure to pre-collapse values. This system may be described over all accessible surface pressures as a two-dimensional liquid-crystal analog at temperatures near and above room temperature. The behavior of this amphiphile is suggested to be related to structural elements of the molecule, particularly the bulky capping group, that may define a class of such systems.     

Optimal Algorithms for <Emphasis Type="Italic">k</Emphasis>-Search with Application in Option Pricing

In the k-search problem, a player is searching for the k highest (respectively, lowest) prices in a sequence, which is revealed to her sequentially. At each quotation, the player has to decide immediately whether to accept the price or not. Using the competitive ratio as a performance measure, we give optimal deterministic and randomized algorithms for both the maximization and minimization problems, and discover that the problems behave substantially different in the worst-case. As an application of our results, we use these algorithms to price “lookback options”, a particular class of financial derivatives. We derive bounds for the price of these securities under a no-arbitrage assumption, and compare this to classical option pricing. J. Lorenz is partially supported by UBS AG. K. Panagiotou is partially supported by the SNF, grant number: 200021-107880/1.     

A Review of Longitudinal Datasets on Ageing

The growth in longitudinal datasets on ageing have resulted from a recent global initiative, in a large part encouraged and partially funded by the NIA, over the past 20 years in numerous countries eager to understand the complexities of their ageing societies. In the main these studies aim to collect data on population ageing in terms of social, medical and environmental factors. Accordingly the studies being compared in this review focus primarily on health, wellbeing and social issues. These studies have made it possible to measure, evaluate and understand a wide variety of determinants of population change and helped to identify the challenges faced on many levels for the twenty first century and beyond. They have enabled organisations, health care service providers and government more readily able to anticipate and be responsive to the need of the dynamics of the population change as not only the population rapidly increases but faces a significant rise in the percentage of elderly persons. This review looks at the aim of each study, comparisons in methodology, key policy themes, benefits, collaborations with other datasets, gaps and challenges and key findings to date. For further information, an appendix is attached with the contact details of the Principal investigator and study website.     

Identification of harmless and pathogenic algae of the genus Prototheca by MALDI-MS

The only plants infectious for mammals, green algae from the genus Prototheca, are often overseen or mistaken for yeast in clinical diagnosis. To improve this diagnostical gap, a method was developed for fast and reliable identification of Prototheca. A collection of all currently recognized Prototheca species, most represented by several strains, were submitted to a simple extraction by 70% formic acid and ACN; the extracts were analyzed by means of MALDI-MS. Most of the peaks were found in the range from 4 to 20 kDa and showed a high reproducibility, not in absolute intensities, but in their peak pattern. The selection of measured peaks is mostly due to the technique of ionization in MALDI-MS, because proteins in the range up to 200 kDa were detected using gel electrophoresis. Some of the proteins were identified by peptide mass fingerprinting and MS² analysis and turned out to be ribosomal proteins or other highly abundant proteins such as ubiquitin. For the preparation of a heatmap, the intensities of the peaks were plotted and a cluster analysis was performed. From the peak-lists, a principal component analysis was conducted and a dendrogram was built. This dendrogram, based on MALDI spectra, was in fairly good agreement with a dendrogram based on sequence information from 18S DNA. As a result, pathogenic and nonpathogenic species from the genus Prototheca can be identified, with possible consequences for clinical diagnostics by MALDI-typing.