Anomalous Self-Energy Effects of the B_1g Phonon in Y_{1-x}(Pr,Ca)_xBa_2Cu_3O_7 Films

In Raman spectra of cuprate superconductors the gap shows up both directly, via a redistribution of the electronic background, the so-called "2Delta peaks", and indirectly, e.g. via the renormalization of phononic excitations. We use a model that allows us to study the redistribution and the related phonon self-energy effects simultaneously. We apply this model to the B_1g phonon of Y_{1-x}(Pr,Ca)_xBa_2Cu_3O_7 films, where Pr or Ca substitution enables us to investigate under- and overdoped samples. While various self-energy effects can be explained by the strength and energy of the 2\Delta peaks, anomalies remain. We discuss possible origins of these anomalies.Comment: 6 pages including 4 figure

Aqueductal developmental venous anomaly as an unusual cause of congenital hydrocephalus: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>Aqueductal stenosis may be caused by a number of etiologies including congenital stenosis, tumor, inflammation, and, very rarely, vascular malformation. However, aqueductal stenosis caused by a developmental venous anomaly presenting as congenital hydrocephalus is even more rare, and, to the best of our knowledge, has not yet been reported in the literature. In this study, we review the literature and report the first case of congenital hydrocephalus associated with aqueductal stenosis from a developmental venous anomaly.</p> <p>Case presentation</p> <p>The patient is a three-day-old, African-American baby girl with a prenatal diagnosis of hydrocephalus. She presented with a full fontanelle, splayed sutures, and macrocephaly. Postnatal magnetic resonance imaging showed triventricular hydrocephalus, suggesting aqueductal stenosis. Examination of the T1-weighted sagittal magnetic resonance imaging enhanced with gadolinium revealed a developmental venous anomaly passing through the orifice of the aqueduct. We treated the patient with a ventriculoperitoneal shunt.</p> <p>Conclusions</p> <p>Ten cases of aqueductal stenosis due to venous lesions have been reported and, although these venous angiomas and developmental venous anomalies are usually considered congenital lesions, all 10 cases became symptomatic as older children and adults. Our case is the first in which aqueductal stenosis caused by a developmental venous anomaly presents as congenital hydrocephalus. We hope adding to the literature will improve understanding of this very uncommon cause of hydrocephalus and, therefore, will aid in treatment.</p

Dysembryoplastic neuroepithelial tumor originally diagnosed as astrocytoma and oligodendroglioma

Dysembryoplastic neuroepithelial tumor (DNT), described in 1988 and introduced in the WHO classification in 1993, affects predominantly children or young adults causing intractable complex partial seizures. Since it is benign and treated with surgical resection, its recognition is important. It has similarities with low-grade gliomas and gangliogliomas, which may recur and become malignant. OBJECTIVES: To investigate whether DNT was previously diagnosed as astrocytoma, oligodendroglioma, or ganglioglioma and to determine its frequency in a series of low-grade glial/glio-neuronal tumors. METHODS: Clinical, radiological, and histological aspects of 58 tumors operated from 1978 to 2008, classified as astrocytomas (32, including 8 pilocytic), oligodendrogliomas (12), gangliogliomas (7), and DNT (7), were reviewed. RESULTS: Four new DNT, one operated before 1993, previously classified as astrocytoma (3) and oligodendroglioma (1), were identified. One DNT diagnosed in 2002 was classified once more as angiocentric glioma. Therefore, 10 DNT (17.2%) were identified. CONCLUSIONS: Clinical-radiological and histopathological correlations have contributed to diagnose the DNT