RESUMO
Sparse matter is abundant and has both strong local bonds and weak nonbonding forces, in particular nonlocal van der Waals (vdW) forces between atoms separated by empty space. It encompasses a broad spectrum of systems, like soft matter, adsorption systems and biostructures. Density-functional theory (DFT), long since proven successful for dense matter, seems now to have come to a point, where useful extensions to sparse matter are available. In particular, a functional form, vdW-DF (Dion et al 2004 Phys. Rev. Lett. 92 246401; Thonhauser et al 2007 Phys. Rev. B 76 125112), has been proposed for the nonlocal correlations between electrons and applied to various relevant molecules and materials, including to those layered systems like graphite, boron nitride and molybdenum sulfide, to dimers of benzene, polycyclic aromatic hydrocarbons (PAHs), doped benzene, cytosine and DNA base pairs, to nonbonding forces in molecules, to adsorbed molecules, like benzene, naphthalene, phenol and adenine on graphite, alumina and metals, to polymer and carbon nanotube (CNT) crystals, and hydrogen storage in graphite and metal-organic frameworks (MOFs), and to the structure of DNA and of DNA with intercalators. Comparison with results from wavefunction calculations for the smaller systems and with experimental data for the extended ones show the vdW-DF path to be promising. This could have great ramifications.
Assuntos
Granulomatose com Poliangiite/complicações , Hidrocefalia/etiologia , Neoplasias Hipofisárias/complicações , Adulto , Antineoplásicos Alquilantes/uso terapêutico , Ciclofosfamida/uso terapêutico , Dapsona/uso terapêutico , Diagnóstico Diferencial , Feminino , Antagonistas do Ácido Fólico/uso terapêutico , Granulomatose com Poliangiite/terapia , Humanos , Hidrocefalia/cirurgia , Invasividade Neoplásica , Neoplasias Hipofisárias/patologia , Sela Túrcica/patologiaRESUMO
Postcontrast CT of the head may be a useful screening technique for identifying an aneurysm within an intracerebral hematoma. This could avoid unnecessary angiography with its attendant morbidity in inoperable situations and obviate initial arteriography in patients whose surgery is to be delayed.
Assuntos
Hemorragia Cerebral/diagnóstico por imagem , Hematoma/diagnóstico por imagem , Aneurisma Intracraniano/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Ruptura EspontâneaRESUMO
This report assessed the relationship between patient selection and the outcome of lumbar disc surgery. Patient selecting is assessed by means of a predictive scoring technique previously reported. Because of the dynamic and ever-changing status of the lumbar spine with the passage of time, patient selectivity seems to be less critical after 5 years. For the first 5 years, however, the outcome of lumbar disc surgery seems to be directly related to patient selectivity.
