Parallel solid-phase synthesis of novel 3,7-diazabicyclo[3.3.1]nonane derivatives starting from natural alkaloid cytisine

A parallel solid-phase synthesis of combinatorial library of 436 amides of 4-(3,7-diorganyl-3,7-diazabicyclo[3.3.1]nonan-2-yl)butanoic acid has been accomplished starting from natural alcaloid (−)-cytisine. A five-step liquid-phase synthesis resulted in the conversion of cytisine to 7-benzyl-3-[(9H-fluoren-9-yl)methyl]-substituted acids, which were further diversified with the use of solid-phase technology on the acid-susceptible amine resins. The combinatorial library obtained is intended for a discovery of new physiologically active compounds. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1964–1970, September, 2008.     

Common model of evolution for living cell and central nervous system.

Both living cell and central nervous system can be treated as objects similar to artificial neural networks, actively studied now. One can see deep analogies between evolutionary processes in these systems, and correspondences can be established between some phenomena and objects. These are: genome vs. memory, gene vs. symbol, cell type vs. image, mitosis vs. sleep, organism vs. perception state, species vs. language, fertilization vs. attention, meiosis vs. paradoxal sleep. There is reason to study these correspondences on more technical level being based upon network nature of the living cell and nervous system.     

Growth of epitaxial graphene: Theory and experiment

A detailed review of the literature for the last 5–10 years on epitaxial growth of graphene is presented. Both experimental and theoretical aspects related to growth on transition metals and on silicon carbide are thoroughly reviewed. Thermodynamic and kinetic aspects of growth on all these materials, where possible, are discussed. To make this text useful for a wider audience, a range of important experimental techniques that have been used over the last decade to grow (e.g. CVD, TPG and segregation) and characterize (STM, LEEM, etc.) graphene are reviewed, and a critical survey of most important theoretical techniques is given. Finally, we critically discuss various unsolved problems related to growth and its mechanism which we believe require proper attention in future research.     

Access to novel substituted diazaadamantanes via semi-natural tetrahydrocytisine

Novel 1,3-diazaadamantane structures 3 and 6 were prepared from tetrahydro(−)-cytisine 1 using intermolecular conversions within the bispidine moiety. 2-Oxo derivative 6 was synthesized using a microwave-assisted procedure, which reduces the reaction time and increases the purity of the crude reaction mixture. Alternative possibilities of intermolecular cyclizations were also explored. Though less successful, they provided interesting insights into the chemistry of bispidine systems.     

Risk,randomness, crashes and quants

Market movements, whether short-term fluctuations, long-term trends, or sudden surges or crashes, have an immense and widespread economic impact. These movements are suggestive of the complex behaviour seen in many non-equilibrium physical systems. Not surprisingly, therefore, the characterization of market behaviour presents an inviting challenge to the physical sciences and, indeed, many concepts and methods developed for modelling non-equilibrium natural phenomena have found fertile ground in financial settings. In this review, we begin with the simplest random process, the random walk, and, assuming no prior knowledge of markets, build up to the conceptual and computational machinery used to analyse and model the behaviour of financial systems. We then consider the evidence that calls into question several aspects of the random walk model of markets and discuss some ideas that have been put forward to account for the observed discrepancies. The application of all of these methods is illustrated with examples of actual market data.     

Nonlinear theory for epitaxial growth of semiconductor alloys on vicinal surfaces

A set of coupled nonlinear diffusion equations is derived for describing the epitaxial growth of semiconductor alloys on vicinal surfaces. The equations include diffusion and a quadratic interaction term to account for incipient island formation. A criterion is obtained for determining the temperature T_c at which growth becomes dominated by step advancement as a function of alloy composition, substrate temperature, and growth rate. The sensitivity of T_c to variations in the interaction parameters is briefly discussed.     

Operator expansions for critical dynamics

We derive the operator expansion method for dynamical one-particle-irreducible renormalization-group generators and apply the technique by calculating the exponents z and η to order ε² for selected time-dependent Ginzburg-Landau models.