Controlled self-assembly of short ß-helical peptides

Cells as functional units from algae to mammals demonstrate the most remarkable degree of self-organization. Processes like membrane formation, protein folding and signal cascades excel in selectivity and control. Nanotechnology is often inspired by biological properties but, despite Nature’s seductive elegance and putative simplicity, often fails at prediction of complex self-assembly. Even weak forces, multiplied by the large number of subunits, contribute to the assemblies and frequently lead to unforeseen results. Membranes are prominent and well understood examples for self-organization and since there is a rising interest in vesicular self-assemblies, the number of potential applications increased with the complexity of the membrane material. The controlled variation of structure and dimension in supramolecular assemblies is a desirable feature for medical and technical applications. From lipids to polymers to the incorporation of proteins: today we are able to tailor membrane properties desirable for many purposes. Highly specific interactions in between membrane constituents are a desirable feature. And when it comes to the discipline of self-assembly, barely a process compares to the specificity and control that is represented by proteins folding into their biologically active state. Thus, it is tempting to exploit this specificity not only in terms of intramolecular but also intermolecular interactions. However, the controlled formation of a membrane from short peptides has not been accomplished to this day. The aim of this work was to construct membranes from peptides, shorter than 30 amino acids in primary structure. The main challenge of the project is the hydrophilic contribution of every amino acid’s backbone that usually constrains the hydrophobic property of peptides. As a consequence, we considered secondary structure as the key to the formation of an entirely peptidic membrane constituent, an assumption that was confirmed by the helical conformation of the antibiotic peptide gramicidin. We present the formation of membranes based on its secondary structure motif and complemented it with varying lengths of positively charged oligo-lysine. The functional property of membrane formation could be assigned to the last seven amino acids of the gramicidin sequence, which allowed us to construct membranes out of peptides only eight amino acids in length. The results are unpreceded both in terms of controlled peptide self-assembly as well as abstraction from the peptides’ biological purpose

Is this Twitter event a disaster?

Ponencias, comunicaciones y pósters presentados en el 17th AGILE Conference on Geographic Information Science "Connecting a Digital Europe through Location and Place", celebrado en la Universitat Jaume I del 3 al 6 de junio de 2014.Social media services such as Twitter have become an important channel for reporting real-world events. For example, they can describe the current situation during a disaster. The decisions in crises management are based on detailed on-site information such as what is happening, where and when an event is happening, and who is involved. Thus, in real applications, monitoring the events over social media will enable to analyse the current overall situation. In this paper, the authors introduce a prototype for real-time Twitter-based natural disaster detection and monitoring. The detection approach is multilingual and calculates a statistical based probability for a potential disaster event. For an automatic geo-referencing of the disaster, the approach applies spatial gridding. On this basis the grid cells are subject to a spatial-thematic clustering which uses a method similar to region growing. The application’s output is an automatically generated email alert, containing specific information on the disaster

Палеогеографические условия формирования верхнеюрских отложений Усть-Тымской впадины (Томская область)

На основе детального изучения керна, текстурного, ихнологического и литолого-фациального анализов проведены палеогеографические реконструкции на время накопления продуктивных пластов горизонта Ю-I. Построена серия литолого-фациальных карт, отражающих седиментологические особенности выделенных подразделений. По результатам комплексных исследований керна выделены и описаны 24 литогенетических типа, отнесенных к 18 фациальным обстановкам. Сделан вывод о прибрежноморском генезисе описываемых отложений

Influence of Processing Parameters on Fibre Properties during Twin-Screw Extrusion of Poplar Wood Chips

For sustainable agriculture, the contentious input of peat in growing media needs to be replaced by a substitute with the best possible water-holding capacity (WHC). Wood from fast growing poplar trees, cultivated in short rotation coppices (SRC), is a suitable alternative if it is processed correctly in a twin-screw extruder. The processing parameters, such as the aperture setting of the extruder, moisture content, and specific energy demand (SED), during twin-screw extrusion, as well as their influence on fibre properties such as WHC and particle size distribution, are investigated. SRC-poplar wood chips from clone Max3 are the raw material used for this research. As a result, the best volume-based WHC (75%) at −1 kPa suction tension was achieved for dry extruded wood chip fibre at an aperture setting of 15 mm and an SED of 340 kWh*t−1. The smallest SED of 140 kWh*t−1 was measured at apertures of 35 mm and 40 mm, which resulted in a volume-based WHC of approximately 30% and a dry matter mass flow during processing of 0.289 t*h−1 (40 mm). The particle size distribution of semi-dry wood chips has the highest fine fraction as well as the smallest coarse fraction. Conclusively, poplar wood can be processed fresh and dry into fibre at an acceptable SED, which results in an acceptable WHC

Contribution of secondary currents to momentum fluxes in natural river flows

River hydrodynamicsBed roughness and flow resistanc

Iterated mutual observation with genetic programming

"This paper introduces a simple model of interacting agents that learn to predict each other. For learning to predict the other's intended action we apply genetic programming. The strategy of an agent is rational and fixed. It does not change like in classical iterated prisoners dilemma models. Furthermore the number of actions an agent can choose from is infinite. Preliminary simulation results are presented. They show that by varying the population size of genetic programming, different learning characteristics can easily be achieved, which lead to quite different communication patterns." (author's abstract

Technical paper on Twin screw extruder processing technology for fibres as raw material for peat substitution

One important aim of the Organic-PLUS project is to develop resource and energy efficient technologies to produce fibres from lignocellulosic plant materials as a raw material to substitute peat. For this purpose, Leibniz Institute für Agrartechnik und Bioekonomie (ATB), Germany leads the work in the task 5.3, “Processing of agroforestry and other plant material for improved characteristics”. This report (Project deliverable D5.3) describes one technology available at pilot scale at ATB which changes the characteristics of plant fibres to make them better suited for peat replacement. The process is called extrusion, and is described in this report. The purpose is to inform stakeholders interested in peat replacement, including scientists involved in the Organic-PLUS project, to collect relevant materials for extrusion and to test further utilisations of extruded fibres