Background and Purpose— Dural arteriovenous shunts with cortical venous reflux or drainage may cause neurological symptoms and death with or without intracranial hemorrhage. Present knowledge about the natural history of these lesions is limited, however. We investigated the incidences of intracranial hemorrhage, progressive dementia syndrome, and death in patients diagnosed in our neurovascular center. Methods— We evaluated the records of 85 patients with dural arteriovenous shunts with cortical venous drainage or reflux hospitalized in our institution from 1978 to 2007. The annual incidences of intracranial hemorrhage, progressive dementia syndrome, and death were calculated. Results— Fifty-three patients did not have an intracranial hemorrhage as the presenting event. One of these patients bled after diagnosis. Thirty-two patients had an intracranial hemorrhage as the presenting event. Three patients bled after diagnosis. One of these patients died. Apart from deficits caused by hemorrhage, no patient reported adverse neurological symptoms. In patients presenting with an intracranial hemorrhage the annual risk for hemorrhage is approximately 7.4% and in those not presenting with a hemorrhage it is approximately 1.5%. Conclusion— The risk of intracranial hemorrhage from a dural arteriovenous shunt with cortical venous drainage is most likely smaller than previously proposed. Presentation with hemorrhage is a risk factor for hemorrhage. The risks of developing neurological symptoms not related to hemorrhage are also less than previously reported.

Transformation of electrical transport from ionic to polaronic in glasses, which are a potential class of new cathode materials, has been investigated in four series containing WO3/MoO3 and Li+/Na+ ions, namely: xWO3–(30−0.5x)Li2O–(30−0.5x)ZnO–40P2O5, xWO3–(30−0.5x)Na2O–(30.5x)ZnO–40P2O5, xMoO3–(30−0.5x)Li2O–(30−0.5x)ZnO–40P2O5, and xMoO3–(30−0.5x)Na2O–(30−0.5x)ZnO–40P2O5, 0 ≤ x ≤ 60, (mol%). This study reports a detailed analysis of the role of structural modifications and its implications on the origin of electrical transport in these mixed ionic‐polaron glasses. Raman spectra show the clustering of WO6 units by the formation of W–O–W bonds in glasses with high WO3 content while the coexistence of MoO4 and MoO6 units is evidenced in glasses containing MoO3 with no clustering of MoO6 octahedra. Consequently, DC conductivity of tungstate glasses with either Li+ or Na+ exhibits a transition from ionic to polaronic showing a minimum at about 20‐30 mol% of WO3 as a result of ion‐polaron interactions followed by a sharp increase for six orders of magnitude as WO3 content increases. The formation of WO6 clusters involved in W‐O‐W linkages for tungsten glasses plays a key role in significant increase in DC conductivity. On the other hand, DC conductivity is almost constant for glasses containing MoO3 suggesting an independent ionic and polaronic transport pathways for glasses containing 10‐50 mol% of MoO3.

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