Subcortical brain volume abnormalities in 2028 individuals with schizophrenia and 2540 healthy controls via the ENIGMA consortium

The profile of brain structural abnormalities in schizophrenia is still not fully understood, despite decades of research using brain scans. To validate a prospective meta-analysis approach to analyzing multicenter neuroimaging data, we analyzed brain MRI scans from 2028 schizophrenia patients and 2540 healthy controls, assessed with standardized methods at 15 centers worldwide. We identified subcortical brain volumes that differentiated patients from controls, and ranked them according to their effect sizes. Compared with healthy controls, patients with schizophrenia had smaller hippocampus (Cohen's d=-0.46), amygdala (d=-0.31), thalamus (d=-0.31), accumbens (d=-0.25) and intracranial volumes (d=-0.12), as well as larger pallidum (d=0.21) and lateral ventricle volumes (d=0.37). Putamen and pallidum volume augmentations were positively associated with duration of illness and hippocampal deficits scaled with the proportion of unmedicated patients. Worldwide cooperative analyses of brain imaging data support a profile of subcortical abnormalities in schizophrenia, which is consistent with that based on traditional meta-analytic approaches. This first ENIGMA Schizophrenia Working Group study validates that collaborative data analyses can readily be used across brain phenotypes and disorders and encourages analysis and data sharing efforts to further our understanding of severe mental illness.

Why multilayer graphene on 4H-SiC(0001[over ]) behaves like a single sheet of graphene

We show experimentally that multilayer graphene grown on the carbon terminated SiC(0001[over ]) surface contains rotational stacking faults related to the epitaxial condition at the graphene-SiC interface. Via first-principles calculation, we demonstrate that such faults produce an electronic structure indistinguishable from an isolated single graphene sheet in the vicinity of the Dirac point. This explains prior experimental results that showed single-layer electronic properties, even for epitaxial graphene films tens of layers thick.

Electronic structure of epitaxial graphene layers on SiC: effect of the substrate

A strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over]) 4H-SiC surfaces. We also present evidence of a charge transfer that depends on the interface geometry. Hence the graphene is doped and a gap opens at the Dirac point after three Bernal stacked carbon layers are formed.

Electronic structure of epitaxial graphene layers on SiC: effect of the substrate

A strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over]) 4H-SiC surfaces. We also present evidence of a charge transfer that depends on the interface geometry. Hence the graphene is doped and a gap opens at the Dirac point after three Bernal stacked carbon layers are formed.

An introduction to digital cameras

BACKGROUND AND OBJECTIVES

People in all walks of life are using digital cameras instead of the traditional film cameras. Reasons include simplicity of use, ease of development, ability to incorporate the pictures into documents, potential to edit the pictures easily, and capability to send them by e-mail. This article will briefly discuss digital cameras, how they work, what they can do, and what you should look for in one. Editor's Note: This is the fourth in a series of articles demonstrating and describing information technology. The articles include nontechnical information and are geared toward the computer novice with interest in regional anesthesia and pain medicine.

Tuberous sclerosis type 1: three novel mutations detected in exon 15 by a combination of HDA and TGGE

Tuberous sclerosis (TSC) is an autosomal dominant disorder which is genetically heterogeneous with two genes, TSC1 and TSC2. TSC1 consists of 23 exons with exon 15 being the largest one comprising 559 bp. Representing 16% of the coding region exon 15 harbors 37% of the already identified point mutations in TSC1. Mutation screening of large DNA fragments as TSC1 exon 15 by SSCP has been a problem because of the low sensitivity of this method without subdivision. Therefore, we simultaneously performed heteroduplex analysis (HDA) and temperature gradient gel electrophoresis (TGGE) which are both more suitable for evaluation of fragments of this size. DNA samples of 159 patients with the clinical diagnosis of TSC were screened and a total of seven different mutations in nine unrelated cases were identified, including the three novel mutations 1754delT, 1836delT and R500Q. Comparing the two methods applied, HDA showed a higher sensitivity in detecting frameshift mutations, while TGGE seemed to be more sensitive for the detection of base exchanges. We conclude that the combination of these two methods is appropriate to reach a high degree of sensitivity for the detection of all types of small mutations in large DNA fragments.

Storage of cord blood attracts private-sector interest

Storage of cord blood from their babies can cost parents several hundred dollars, and some private companies are already offering the service. Janis Hass reports that some Canadian specialists question the value of the banks.