Bistable collective behavior of polymers tethered in a nanopore.

Polymer-coated pores play a crucial role in nucleo-cytoplasmic transport and in a number of biomimetic and nanotechnological applications. Here we present Monte Carlo and Density Functional Theory approaches to identify different collective phases of end-grafted polymers in a nanopore and to study their relative stability as a function of intermolecular interactions. Over a range of system parameters that is relevant for nuclear pore complexes, we observe two distinct phases: one with the bulk of the polymers condensed at the wall of the pore, and the other with the polymers condensed along its central axis. The relative stability of these two phases depends on the interpolymer interactions. The existence the two phases suggests a mechanism in which marginal changes in these interactions, possibly induced by nuclear transport receptors, cause the pore to transform between open and closed configurations, which will influence transport through the pore

A dynamic user equilibrium model for traffic assignment in urban areas

info:eu-repo/semantics/publishe

Oscillucusis and sudden deafness in a migraine patient Oscilucusia e perda auditiva em um paciente com migranea

Migraine is a complex disease that includes neurologic, gastrointestinal and autonomic symptoms, although headache is most common feature. In a portion of cases headache is preceded by focal neurologic symptoms termed auras. Auditory symptoms only rarely occur as part of an aura. We describe a patient whose 13-year migraine history that included the abnormal perception an oscillation of the intensity of ambient sounds (oscillucusis). During a migraine attack immediately after oscillucusis, the patient developed acute and permanent sudden deafness. Clinical and neurologic examinations revealed only profound hearing loss in her left ear. Audiometric testing confirmed the sensorineural nature of the hearing loss. The clinical aspects and physiopathology of auditory symptoms in this case and in patients with migraine is reviewed.<br>Migrânea é desordem complexa que inclui sintomas neurológicos, gastrointestinais e autonômicos, na qual a cefaléia é o achado predominante. Em uma parcela de pacientes o quadro álgico pode ser antecipado por sinais neurológicos focais conhecidos como aura. Descrevemos um paciente que iniciou sua historia de migrânea acompanhada por sensações de flutuações nos sons ambientes (oscillucusis) por treze anos. Durante uma crise de cefaléia imediatamente após a oscillucusia o paciente desenvolveu um quadro agudo e permanente de perda auditiva. Exames clínicos e neurológicos revelaram somente uma perda profunda da audição em ouvido esquerdo, cuja natureza sensorioneural foi confirmada por uma avaliação audiométrica. Os aspectos clinicos e fisiopatológicos dos sintomas auditivos encontrados neste caso e em pacientes com migrânea com aura são revisados e comentados