Selective Aptamer‐Based Control of Intraneuronal Signaling

Cellular behavior is orchestrated by the complex interactions of a myriad of intracellular signal transduction pathways. To understand and investigate the role of individual components in such signaling networks, the availability of specific inhibitors is of paramount importance. We report the generation and validation of a novel variant of an RNA aptamer that selectively inhibits the mitogen‐activated kinase pathway in neurons. We demonstrate that the aptamer retains function under intracellular conditions and that application of the aptamer through the patch‐clamp pipette efficiently inhibits mitogen‐activated kinase‐dependent synaptic plasticity. This approach introduces synthetic aptamers as generic tools, readily applicable to inhibit different components of intraneuronal signaling networks with utmost specificity.     

Isoperimetric quotients for a decomposed convex body

In the Euclidean plane, decompose a convex body T into n\geq 2 convex bodies T ₁ ,\ldots ,T _n with areas also denoted by T ₁ ,\ldots ,T _n , and with perimeters L ₁ ,\ldots ,L _n . For T a polygon with at most six sides, G. Fejes Tóth and also L. Fejes Tóth showed that the isoperimetric quotient (L ₁ + ⋅s + L _n )/(\sqrt T ₁ + ⋅s + \sqrt T _n ) is greater than the corresponding isoperimetric quotient of a regular hexagon if T _i /T _j for any i, j is bounded from below by some appropriate constant. We generalize this result to any convex body T , and we show the analogous result for the isoperimetric quotient (L ² ₁ + ⋅s + L ² _n )/(T ₁ + ⋅s + T _n ) . Received April 21, 1999, and in revised form June 21, 2000. Online publication January 17, 2001.     

Eine Charakterisierung der Sphäre im E3

It is well known, that in E³ the spheres are the closed convex C² -surfaces having the property, that each of their closed C²-curves with the total geodesic curvature O bisects the area of the surface. This characterization will be transmitted into the theory of convex surfaces founded by A.D.Alexandrov, where convex surfaces without any differentiability property are studied.     

Gaps in the numbers of vertices of cubical polytopes,I

A cubical polytope is a convex polytope of which very facet is a combinatorial cube. We ask for the numbers which occur as vertex numbers ofd-dimensional cubical polytopes, and we show, as a first step, that every cubicald-polytope for evend≥4 has an even number of vertices.     

Overview of policies,standards and certifications supporting the European bio-based economy

With the Lisbon agenda, the EU recognizes the important role of an economy driven by innovation in tackling contemporary societal challenges. This transition to innovative and sustainable modes of production and consumption is being shaped by policy efforts and policy instruments, including regulations, certifications, standards and sustainability assessment tools. In this paper, we present an overview of the different public policies and policy measures behind the establishment of a European sustainable bio-based economy. The aim of the paper is to describe the evolution of the policies and policy instruments that affect the establishment of a sustainable and innovative bio-based economy, in order to understand its limits, contradictions and existing gaps.     

Intramers as promising new tools in functional proteomics

Aptamers are valuable tools for studying numerous aspects of biological processes, opening up new experimental opportunities to analyse the function of a wide range of cellular molecules. Functional RNA molecules can be rapidly selected in vitro from complex combinatorial mixtures of different sequences. Recently, it was shown that in vitro selection processes can be automated: the first generation selection robots will soon mean aptamers for several targets can be isolated in parallel within days rather than weeks. Aptamers not only exhibit highly specific molecular recognition properties but are also able to modulate the function of their cognate targets in a highly specific manner by agonistic or antagonistic mechanisms. These properties prompted the development of novel technologies to exploit the use of aptamers to modulate distinct functions of biological targets. Recent controlled expression of aptamers inside cells demonstrated their impressive potential as rapidly generated intracellular inhibitors of biomolecules. Intracellularly applied aptamers are also called 'intramers'. Here we discuss recent developments and strategies for intramer-based technologies that have the potential to greatly facilitate characterisation of unknown protein functions in the context of their natural expression status in vivo. Thus, intramer-based technologies offer many promising applications in functional genomics, proteomics and drug discovery.     

Über die minimalen Seitenzahlen von Polytopen ohne dreieckige 2-Seiten

LetP be ad-polytope without triangular 2-faces,K ad-cube andf _n (P),f _n (K) the respective number ofn-faces. It is shown for simpleP or in dimensiond4 thatf _n (P)f _n (K), and for anyn equality holds if and only ifP andK are combinatorially equivalent.