RESUMO
Networks of the cytoskeletal biopolymer actin cross-linked by the compliant protein filamin form soft gels that stiffen dramatically under shear stress. We demonstrate that the elasticity of these networks shows a strong dependence on the mean length of the actin polymers, unlike networks with small, rigid cross-links. This behavior is in agreement with a model of rigid filaments connected by multiple flexible linkers.
Assuntos
Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Reagentes de Ligações Cruzadas/farmacologia , Elasticidade/fisiologia , Citoesqueleto de Actina/ultraestrutura , Actinas/ultraestrutura , Animais , Proteínas Contráteis/metabolismo , Módulo de Elasticidade/efeitos dos fármacos , Elasticidade/efeitos dos fármacos , Filaminas , Gelsolina/metabolismo , Humanos , Proteínas dos Microfilamentos/metabolismo , Dinâmica não Linear , Maleabilidade/efeitos dos fármacos , Coelhos , Estresse Fisiológico/efeitos dos fármacos , Viscosidade/efeitos dos fármacosRESUMO
Double differences of masses can be used to isolate specific nucleonic interactions. With the new 2003 mass tabulation a significant increase in the number of empirical average proton-neutron interactions of the last nucleons can be extracted. It is shown that they exhibit dramatic and distinctive patterns, especially near doubly magic nuclei, that these patterns can be interpreted with a simple ansatz based on overlaps of proton and neutron orbits, and that the trends in p-n interactions across entire shells can be understood if they are correlated with the fractional shell filling. It is shown how these empirical interactions can be sensitive to changes in shell structure in exotic nuclei. Finally, these results are used to suggest criteria for future mass measurements with new exotic beam facilities.
