Disappearance of the Hummingbird Sign after Shunt Surgery in a Case of Idiopathic Normal Pressure Hydrocephalus.

A 79-year-old man presented with a slowly progressive gait disturbance. Brain MRI demonstrated ventriculomegaly and the hummingbird sign. A lumbar puncture showed no abnormalities of the cerebrospinal fluid. The improvement of the gait disturbance after the ventriculoperitoneal shunt led to a diagnosis of idiopathic normal pressure hydrocephalus. Interestingly, postoperative brain MRI demonstrated the disappearance of not only ventriculomegaly, but also the hummingbird sign. The disappearance of the hummingbird sign suggests that an increase in the cerebrospinal fluid in the lateral and third ventricles could cause the compression of the superior surface of the midbrain tegmentum, which manifests as the hummingbird sign.

Enhanced deep-red luminescence of tris(hexafluoroacetylacetonato)samarium(III) complex with phenanthroline in solution by control of ligand coordination.

The effect of solvent molecule on the emission properties of Sm(hfa)3(phen)2 (hfa = hexafluoroacetylacetonato, phen = phenanthoroline) was investigated using acetone, acetonitrile, and pyridine. 5G(5/2) --> 5H(9/2) transition intensities in pyridine were found to be larger than those in corresponding acetone and acetonitrile. The radiative rate constant in pyridine (4.8 x 10(2) s(-1)) was 2 times larger than those in acetonitrile (2.6 x 10(2) s(-1)) and acetone (2.3 x 10(2) s(-1)), although the nonradiative transition via vibrational relaxation (k(nr) = 1.7 x 10(4) s(-1)) in pyridine was the same as those in acetone and acetonitrile (k(nr) = 1.8 x 10(4) s(-1)), resulting in the enhanced emission quantum yield of Sm(III) complex in pyridine (2.7%). The coordination structures of Sm(hfa)3(phen)2 in acetonitrile, acetone, and pyridine were estimated by X-ray single-crystal analyses. These results indicate that enhancement of the emission properties in pyridine is due to faster radiative rate related to formation of asymmetrical nine-coordinated structure, Sm(hfa)3(phen)(py) (py = pyridine).