Time filter

Source Type

Budapest, Hungary

The Hungarian Academy of science ) is the most important and prestigious learned society of Hungary. Its seat is at the bank of the Danube in Budapest. The main responsibilities are the cultivation of science, disseminate the results of science, the supporting of research and development and the representation of Hungarian science domestically and around the world. Wikipedia.

Kiss L.,University of Szeged | Fulop F.,University of Szeged | Fulop F.,Hungarian Academy of Sciences
Chemical Reviews | Year: 2014

Alicyclic and heterocyclic β-amino acids become an expanding area in organic and medicinal chemistry. The biological characteristics of the cyclic β-amino acids as independent molecular entities, together with their usage as precursors of different heterocycles, as chiral auxiliaries in asymmetric syntheses, and as precursors of β-lactams and in foldamer chemistry. Reductive amination of β-keto esters is a suitable method also for the synthesis of functionalized racemic carbocyclic β-amino acids. Carbocyclic β-amino acids can be prepared from acyclic β-amino acid derivatives by ring-closing metathesis. An important advantage of this methodology is that it gives cyclic β-amino acids whose olefinic bond may be functionalized to yield novel substituted derivatives. Stereoselective conjugate addition of an amine nucleophile derivative to an α,β-unsaturated carboxylate is an efficient strategy for access to five- or six-membered cyclic β-amino acids. Source

Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review X | Year: 2014

Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionarily advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding, and punishment, a fourth strategy that combines the latter two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet, despite the high complexity of solutions, the combined strategy can survive only in very narrow and unrealistic parameter regions. Elementary strategies, either in pure or mixed phases, are much more common and likely to prevail. Our results highlight the importance of patterns and structure in human cooperation, which should be considered in future experiments. Source

Tompa P.,Vrije Universiteit Brussel | Tompa P.,Hungarian Academy of Sciences
Chemical Reviews | Year: 2014

Allostery is a classical regulatory mechanism of proteins in which a signal at 'another site' modifies the activity/function of a protein. In fact, with the recognition of the generality of the structural disorder of proteins and the landscape theory of protein structure, a 'new view' of allostery started to emerge, in which emphasis is placed on ligand-induced shifts in the conformational ensemble of the protein. The ensuing changes in ligand binding/catalytic activity might stem from coupled folding transitions of distinct binding sites or remodeling of the conformational landscape to entropically favor a particular downstream binding/catalytic event. The ensuing sigmoidal binding isotherm cannot be described by a simple saturation; rather, it shows signs of cooperation between ligands. If binding of one ligand weakens that of the others, one can also speak about negative cooperativity. To elucidate the underlying mechanistic changes, two models have been suggested, which, even today, form the basis of our textbook wisdom of this phenomenon. Source

Tompa P.,Vrije Universiteit Brussel | Tompa P.,Hungarian Academy of Sciences
Trends in Biochemical Sciences | Year: 2012

The suggestion that the native state of many proteins is intrinsically disordered (or, as originally termed, unstructured) is now integral to our general view of protein structure and function. A little more than 10 years ago, however, such challenge to the almost dogmatic 'structure-function paradigm' was pure heresy due to the overwhelming evidence that structure determines function. A decade of steady progress turned skepticism around: this 10-year recap review outlines the situation a decade ago and the major directions of the breathtaking advance achieved by experimental and computational approaches. I show that the evidence for the generality and importance of this phenomenon is now so insurmountable that it demands the inclusion of 'unstructural' biology into mainstream biology and biochemistry textbooks. © 2012 Elsevier Ltd. Source

An insight into the homogeneous catalytic asymmetric reactions, the organocatalytic reactions, and the heterogeneous catalytic asymmetric reactions was studied. In asymmetric reactions/syntheses of this type, chiral induction is supplied by chiral molecules of natural origin and their synthetic derivatives, or other synthetic chiral compounds. Studies on the stereochemistry of homogeneous asymmetric reactions have taken their models from the hydrogenation and transfer hydrogenation of prochiral compounds with CdC bonds and prochiral ketones in the presence of Rh and Ru complexes. Supported IL catalysts (SILC) have been developed using surface-modified silica, which show good reactivity and reversal of enantioselectivity for the case of the magnesium-based BOX complexes. Studies using Pt catalysts modified with cinchona alkaloids gave unexpected results when derivatives of the parent alkaloids were used. Source

Discover hidden collaborations