Electronic and magnetic properties of epitaxial perovskite SrCrO₃(0 0 1)

We have investigated the intrinsic properties of SrCrO3 epitaxial thin films synthesized by molecular beam epitaxy. We find compelling evidence that SrCrO3 is a correlated metal. X-ray photoemission valence band and O K-edge x-ray absorption spectra indicate a strongly hybridized Cr3d-O2p state crossing the Fermi level, leading to metallic behavior. Comparison between valence band spectra near the Fermi level and the densities of states calculated using density functional theory (DFT) suggests the presence of coherent and incoherent states and points to strong electron correlation effects. The magnetic susceptibility can be described by Pauli paramagnetism at temperatures above 100 K, but reveals antiferromagnetic behavior at lower temperatures, possibly resulting from orbital ordering.

Lack of pharmacokinetic drug interactions between tiagabine and carbamazepine or phenytoin

Two single-center, open-label studies examined the potential effects of tiagabine on the pharmacokinetics and safety of carbamazepine and phenytoin at steady state. Twelve adult patients with seizures controlled by an individualized fixed dosage of antiepilepsy medication (carbamazepine or phenytoin) participated in each study. On day 1, the pharmacokinetics of the baseline antiepilepsy drug were determined. On days 2 through 18, tiagabine was titrated from 8 to 48 mg/d (or the maximum tolerated dose up to 48 mg/d), and the usual fixed dosage of carbamazepine or phenytoin was continued. The pharmacokinetic assessment was repeated on day 18. There were no statistically significant differences in carbamazepine, carbamazepine epoxide, and phenytoin pharmacokinetic parameters when either drug was administered alone or in combination with tiagabine. In each study, 11 of 12 patients (92%) experienced treatment-emergent adverse events after tiagabine was added. The most frequent adverse events were dizziness, headache, difficulty concentrating, drowsiness, and tremor. Most symptoms were mild or moderate in severity and resolved without further treatment, although tiagabine dosage reductions were required by 4 patients in the carbamazepine study and by 3 patients in the phenytoin study. There were no clinically important effects on physical examination or neurologic test results, laboratory values, or vital signs. The results suggest that addition of tiagabine to a fixed regimen of either carbamazepine or phenytoin is generally well tolerated and that carbamazepine and phenytoin steady-state pharmacokinetics are unaffected by the addition of tiagabine.

[Intracranial arachnoid cyst: report of 23 cases]

Twenty-three cases of intracranial arachnoid cyst are reported. Among them 8 cases developed primarily and 15 secondarily. There are 19 male and 4 female, ages ranged 3 to 40 years. The duration of illness were one month to 32 years. There are 19 cases located supratentoriumly and 4 subtentoriumly. Most of them were situated at Sylvius fissure (13 cases). 22 cases were treated by partial resection of the cyst and different kinds of shunt operations. Short-term follow-up study showed that the results were excellent without operative death. The etiology, pathogenesis, diagnosis of this disease and operative indications are discussed.