Generating functional analysis of complex formation and dissociation in large protein interaction networks

We analyze large systems of interacting proteins, using techniques from the non-equilibrium statistical mechanics of disordered many-particle systems. Apart from protein production and removal, the most relevant microscopic processes in the proteome are complex formation and dissociation, and the microscopic degrees of freedom are the evolving concentrations of unbound proteins (in multiple post-translational states) and of protein complexes. Here we only include dimer-complexes, for mathematical simplicity, and we draw the network that describes which proteins are reaction partners from an ensemble of random graphs with an arbitrary degree distribution. We show how generating functional analysis methods can be used successfully to derive closed equations for dynamical order parameters, representing an exact macroscopic description of the complex formation and dissociation dynamics in the infinite system limit. We end this paper with a discussion of the possible routes towards solving the nontrivial order parameter equations, either exactly (in specific limits) or approximately.Comment: 14 pages, to be published in Proc of IW-SMI-2009 in Kyoto (Journal of Phys Conference Series

Estudo das atividades lipolíticas de fungos isolados de riachos da região de Foz do Iguaçu - PR

Anais do V Encontro de Iniciação Científica e I Encontro Anual de Iniciação ao Desenvolvimento Tecnológico e Inovação – EICTI 2016 - 05 e 07 de outubro de 2016 – Sessão Ciências Exatas e da TerraA busca por novas enzimas com atividades lipolíticas apresenta-se como uma importante alternativa no estabelecimento de novas tecnologias destinadas a processos industriais sustentáveis. Com uma ampla gama de aplicações biotecnológicas, estas enzimas (responsáveis pelas hidrólises de ésteres e lipídios) apresentam papel biotecnológico fundamental, sendo aplicadas desde a formulação de detergentes e biocombustíveis até sínteses complexas de polímeros e drogas biologicamente ativas [1]. Esta vasta gama de aplicações requer a descoberta de novos biocatalisadores com propriedades biológicas direcionadas, e isto incentiva o estudo dos mais deferentes nichos. Assim, fungos envolvidos em processos de decomposição apresentam-se como ferramentas-chave na busca de novos biocatalisadores, uma vez que estes micro-organismos têm sido associados à uma grande produção de lipases extracelulares [2]. Nesse contexto, este trabalho apresenta um interessante estudo do potencial lipolítico de uma microbiota isolada de detritos vegetais de riachos da região de Foz do Iguaçu – PR aplicando técnicas qualitativas e quantitativas que permitam a investigação do potencial enzimático da microbiota de interesse

Non-thermal origin of nonlinear transport across magnetically induced superconductor-metal-insulator transition

We have studied the effect of perpendicular magnetic fields and temperatures on the nonlinear electronic transport in amorphous Ta superconducting thin films. The films exhibit a magnetic field induced metallic behavior intervening the superconductor-insulator transition in the zero temperature limit. We show that the nonlinear transport in the superconducting and metallic phase is of non-thermal origin and accompanies an extraordinarily long voltage response time.Comment: 5 pages, 4 figure

Weak Quasi-elastic Production of Hyperons

The quasielastic weak production of $\Lambda$ and $\Sigma$ hyperons from nucleons and nuclei induced by antineutrinos is studied in the energy region of some ongoing neutrino oscillation experiments in the intermediate energy region. The hyperon nucleon transition form factors determined from neutrino nucleon scattering and an analysis of high precision data on semileptonic decays of neutron and hyperons using SU(3) symmetry have been used. The nuclear effects due to Fermi motion and final state interaction effects due to hyperon nucleon scattering have also been studied. The numerical results for differential and total cross sections have been presented.Comment: 26 pages, 10 figure

Tilt Induced Localization and Delocalization in the Second Landau Level

We have investigated the behavior of electronic phases of the second Landau level under tilted magnetic fields. The fractional quantum Hall liquids at $\nu=$2+1/5 and 2+4/5 and the solid phases at $\nu=$2.30, 2.44, 2.57, and 2.70 are quickly destroyed with tilt. This behavior can be interpreted as a tilt driven localization of the 2+1/5 and 2+4/5 fractional quantum Hall liquids and a delocalization through melting of solid phases in the top Landau level, respectively. The evolution towards the classical Hall gas of the solid phases is suggestive of antiferromagnetic ordering