Phase Diagram of alpha-Helical and beta-Sheet Forming Peptides

The intrinsic property of proteins to form structural motifs such as alpha-helices and beta-sheets leads to a complex phase behavior in which proteins can assemble into various types of aggregates including crystals, liquidlike phases of unfolded or natively folded proteins, and amyloid fibrils. Here we use a coarse-grained protein model that enables us to perform Monte Carlo simulations for determining the phase diagram of natively folded alpha-helical and unfolded beta-sheet forming peptides. The simulations reveal the existence of various metastable peptide phases. The liquidlike phases are metastable with respect to the fibrillar phases, and there is a hierarchy of metastability

Arbeitsmarkt- und Organisationswandel: Zukünftige Arbeitsstrukturen und ältere Arbeitnehmer

Die vorliegende Studie ist Teil eines Projektes zur Analyse von neuen Fertigungsstrukturen in der europäischen Automobilindustrie und untersucht die Verbindung zwischen diesen Fertigungsstrukturen und der Beschäftigtenstruktur auf internen Arbeitsmärkten in den letzten zehn Jahren anhand von Fallbeispielen aus Unternehmen und Einzelwerken der Automobilindustrie in Deutschland, Frankreich und Großbritannien. Flexible Fertigungstechniken, Gruppenarbeit mit dezentralisierten Entscheidungsstrukturen, Integration von Arbeitsaufgaben und "job-rotation" über eng definierte Funktionsbereiche hinaus verlangen nach gut ausgebildeten und zum kontinuierlichen Ausbau ihrer Fähigkeiten bereiten Arbeitskräften. Generell werden diese Fähigkeiten der jüngeren Arbeitergenerationen nachgesagt. Ein Blick auf die meisten der internen Arbeitsmärkte der für diese Studie ausgewählten Firmen zeigt jedoch, daß die dortige Arbeitskräftestruktur nicht diesem Bild entspricht: die existierenden Arbeitsmärkte bestehen oftmals aus älteren Arbeitskräften mit verhältnismäßig geringen Qualifikationen und Barrieren hinsichtlich einer kontinuierlichen Fortbildung. Diese Arbeitsmarktstrukturen haben sich in den letzten 10 Jahren nur unwesentlich verbessert und meistens sogar verschlechtert, trotz der mit hohen Kosten verbundenen Frühverrentungsprogramme. -- The present study is part of a research project which analyses the development of future working structures in the European auto industry. Its focus lies on the interfaces between new working structures and the employment structures on internal labour markets. This interface is analysed through case studies in companies and individual plants of the auto industry in Germany, France and the UK. Flexible manufacturing systems, team work with decentralisation of decisionmaking, integration of tasks and multiple allocation across functional barriers demand a skilled workforce prepared for continuous learning and adaptation. It is common to see a younger, well educated and trained workforce as being required for such a production environment. A closer empirical look on most of the internal labour markets in this study shows, that existing labour market structures do not match this image. Existing labour markets consist very often of an older (and ageing) labour force with relatively low skills and with barriers for continuous training. This structural features have, over the last ten years - despite the existence of costly early retirement measures and the new entries into internal labour markets - not much improved and in many cases even deteriorated.

Self-Templated Nucleation in Peptide and Protein aggregation

Peptides and proteins exhibit a common tendency to assemble into highly ordered fibrillar aggregates, whose formation proceeds in a nucleation-dependent manner that is often preceded by the formation of disordered oligomeric assemblies. This process has received much attention because disordered oligomeric aggregates have been associated with neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Here we describe a self-templated nucleation mechanism that determines the transition between the initial condensation of polypeptide chains into disordered assemblies and their reordering into fibrillar structures. The results that we present show that at the molecular level this transition is due to the ability of polypeptide chains to reorder within oligomers into fibrillar assemblies whose surfaces act as templates that stabilise the disordered assemblies.Comment: 4 pages, 3 figure

Extranodal lymphomas of the gastrointestinal tract

Pozawęzłowe chłoniaki często zajmują przewód pokarmowy (GI) i są wtedy dużym wyzwaniem diagnostycznym dla klinicystów i patologów. Pozawęzłowe chłoniaki przewodu pokarmowego (EGIL) cechują różna etiologia i prezentacje kliniczne, obejmujące ostre lub przewlekłe objawy brzuszne. Mogą wystąpić w każdym przedziale wieku i mieć zróżnicowany obraz morfologiczny, podobnie jak w przypadku chłoniaków o lokalizacji węzłowej. Prawidłowego rozpoznania EGIL powinno się dokonywać na podstawie danych klinicznych, wyników badań uzyskanych metodami endoskopowymi i chirurgicznymi oraz oceny histopatologicznej, dokonanej przez doświadczonego patologa. Niniejsza praca jest omówieniem tych zagadnień z perspektywy lekarza patologa. Hematologia 2010; 1, 4: 280-287Extranodal lymphomas commonly involve the gastrointestinal tract (GI) and often present a diagnostic challenge for both clinicians and pathologists. Extranodal GI lymphomas (EGIL) have varied aetiology and may present as an acute emergency or chronically with vague abdominal symptoms in every age group. Morphologically they are as varied as any nodal lymphoma. The optimal diagnosis subclassification of these lesions requires a high index of suspicion on the part of the clinician, skilled endoscopist, or surgeon and a pathologist familiar with a range of presentations and diagnostic criteria. This review paper focuses on EGIL from the pathologist’s perspective. Hematologia 2010; 1, 4: 280-28

Nucleation of amyloid fibrils

We consider nucleation of amyloid fibrils in the case when the process occurs by the mechanism of direct polymerization of practically fully extended protein segments, i.e. beta-strands, into beta-sheets. Applying the classical nucleation theory, we derive a general expression for the work to form a nanosized amyloid fibril (protofilament) constituted of successively layered beta-sheets. Analysis of this expression reveals that with increasing its size, the fibril transforms from one-dimensional into two-dimensional aggregate in order to preserve the equilibrium shape corresponding to minimal formation work. We determine the size of the fibril nucleus, the fibril nucleation work and the fibril nucleation rate as explicit functions of the concentration and temperature of the protein solution. The results obtained are applicable to homogeneous nucleation which occurs when the solution is sufficiently pure and/or strongly supersaturated

Crystal Nucleation of Colloidal Suspensions under Shear

We use Brownian Dynamics simulations in combination with the umbrella sampling technique to study the effect of shear flow on homogeneous crystal nucleation. We find that a homogeneous shear rate leads to a significant suppression of the crystal nucleation rate and to an increase of the size of the critical nucleus. A simple, phenomenological extension of classical nucleation theory accounts for these observations. The orientation of the crystal nucleus is tilted with respect to the shear direction.Comment: 4 pages, 3 figures, Submitted to Phys. Rev. Let

Exploiting Deep Matching and SAR Data for the Geo-Localization Accuracy Improvement of Optical Satellite Images

Improving the geo-localization of optical satellite images is an important pre-processing step for many remote sensing tasks like scene monitoring over time or the scene analysis after sudden events. These tasks often require the fusion of geo-referenced and precisely co-registered multi-sensor data. Images captured by high resolution synthetic aperture radar (SAR) satellites have an absolute geo-location accuracy within few decimeters. This renders SAR images interesting as a source for the geo-location improvement of optical images, whose geo-location accuracy is in the range of some meters. In this paper, we are investigating a deep learning based approach for the geo-localization accuracy improvement of optical satellite images through SAR reference data. Image registration between SAR and optical satellite images requires few but accurate and reliable matching points. To derive such matching points a neural network based on a Siamese network architecture was trained to learn the two dimensional spatial shift between optical and SAR image patches. The neural network was trained over TerraSAR-X and PRISM image pairs covering greater urban areas spread over Europe. The results of the proposed method confirm that accurate and reliable matching points are generated with a higher matching accuracy and precision than state-of-the-art approaches

The Sarrazin effect: the presence of absurd statements in conspiracy theories makes canonical information less plausible

Reptile prime ministers and flying Nazi saucers—extreme and sometimes off-wall conclusion are typical ingredients of conspiracy theories. While individual differences are a common research topic concerning conspiracy theories, the role of extreme statements in the process of acquiring and passing on conspiratorial stories has not been regarded in an experimental design so far. We identified six morphological components of conspiracy theories empirically. On the basis of these content categories a set of narrative elements for a 9/11 story was compiled. These elements varied systematically in terms of conspiratorial allegation, i.e., they contained official statements concerning the events of 9/11, statements alleging to a conspiracy limited in time and space as well as extreme statements indicating an all-encompassing cover-up. Using the method of narrative construction, 30 people were given a set of cards with these statements and asked to construct the course of events of 9/11 they deem most plausible. When extreme statements were present in the set, the resulting stories were more conspiratorial; the number of official statements included in the narrative dropped significantly, whereas the self-assessment of the story's plausibility did not differ between conditions. This indicates that blatant statements in a pool of information foster the synthesis of conspiracy theories on an individual level. By relating these findings to one of Germany's most successful (and controversial) non-fiction books, we refer to the real-world dangers of this effect