Biophysical Reviews and Letters

Amyloid fibrils represent a generic class of mechanically strong and stable biomaterials with extremely advantageous properties. Although amyloids were initially associated only with severe neurological disorders, the role of these structures nowadays is shifting from health debilitating to highly beneficial both in biomedical and technological aspects. Intensive involvement of fibrillar assemblies into the wide range of pathogenic and functional processes strongly necessitate the molecular level characterization of the structural, physical and elastic features of protein nanofibrils. In the present contribution, we made an attempt to highlight the up-to-date progress in the understanding of amyloid properties from the polymer physics standpoint. The fundamental insights into protein fibril behavior are essential not only for development of therapeutic strategies to combat the protein misfolding disorders but also for rational and precise design of novel biodegradable protein-based nanopolymers.

Modeling the dynamics in nations from economical and sociological perspectives is a central theme in economics and sociology. Accurate models can predict and therefore help all the world's citizens. Yet, recent years have show that the current models are missing. Here, we develop a dynamical society-deciders model that can explain the stability in a nation, based on concepts from dynamics, ecology and socio-econo-physics; a nation has two groups that interconnect, the deciders and the society. We show that a nation is either stable or it collapses. This depends on just two coefficients that we relate with sociological and economical indicators. We define a new socio-economic indicator, fairness. Fairness can measure the stability in a nation and how probable a change favoring the society is. We compute fairness among all the world's nations. Interestingly, in comparison with other indicators, fairness shows that the USA loses its rank among Western democracies, India is the best among the 15 most populated nations, and Egypt, Libya and Tunisia have significantly improved their rankings as a result of recent revolutions, further increasing the probability of additional positive changes. Within the model, long lasting crises are solved rather than with increasing governmental spending or cuts with regulations that reduce the stability of the deciders, namely, increasing fairness, while, for example, shifting wealth in the direction of the people, and therefore increasing further opportunities.

Progress towards detailed characterization of structural and biophysical properties of dendrites emphasizes the importance of finding analytical solutions for more realistic dendrite models with circular cross-section and varying diameter. In this regard, we employ symmetry methods and the passive cable theory to deduce a generalized analytical solution for electric propagation in a family of tapering dendrites. In particular, we study the effect of such tapering geometries on the obtained electric voltage. Simulations using the deduced analytical solution indicate that for a subfamily of tapering profiles neural integration is better than in the stereotypical profile given by a cylinder.