Electronic structures and magnetism of diluted magnetic semiconductors Sn1−xGdxTe: A density functional theory study J. Appl. Phys. 112, 083720 (2012) Model GW study of the late transition metal monoxides J. Chem. Phys. 137, 154110 (2012) High-temperature thermoelectric properties of the double-perovskite ruthenium oxide (Sr1−xLax)2ErRuO6 J. Appl. Phys. 112, 073714 (2012) Thermoelectric effect in a graphene sheet connected to ferromagnetic leads J. Appl. Phys. 112, 073712 (2012) Optoelectronic and magnetic properties of Mn-doped indium tin oxide: A first-principles studyThe temperature dependence of the saturation magnetization and the magnetocrysta11ine anisotropy field have been measured on single-crystal samples of the R 2 Fe l4 B compounds for R = Y, Ce, Pr, Nd, Sm, Gd, Th, Dy, Ho, Br, and Tm from 4.2 K to the magnetic ordering temperatures. A spin reorientation transition of the Nd 2 Fe l4 B type has been found in H0 2 Fe l4 B at 57.6 K in zero field. Another type of spin reorientation caused by anisotropy compensation between the Fe and the R sublattices exists in Er 2 Fe 14 B and Tm 2 Fe I4 B. The temperature dependence of the angle of the easy direction of magnetization from the c axis has been measured for R = Nd, Ho, Er, and Tm. The relation between the magnetocrystalline anisotropy and the sublattice magnetization is investigated by employing a simplified two-sublattice molecular field model.

As a sequel of brain ischemia, selective neuronal loss (SNL)-as opposed to pannecrosis (i.e. infarction)-is attracting growing interest, particularly because it is now detectable in vivo. In acute stroke, SNL may affect the salvaged penumbra and hamper functional recovery following reperfusion. Rodent occlusion models can generate SNL predominantly in the striatum or cortex, showing that it can affect behavior for weeks despite normal magnetic resonance imaging. In humans, SNL in the salvaged penumbra has been documented in vivo mainly using positron emission tomography and 11 C-flumazenil, a neuronal tracer validated against immunohistochemistry in rodent stroke models. Cortical SNL has also been documented using this approach in chronic carotid disease in association with misery perfusion and behavioral deficits, suggesting that it can result from chronic or unstable hemodynamic compromise. Given these consequences, SNL may constitute a novel therapeutic target. Selective neuronal loss may also develop at sites remote from infarcts, representing secondary 'exofocal' phenomena akin to degeneration, potentially related to poststroke behavioral or mood impairments again amenable to therapy. Further work should aim to better characterize the time course, behavioral consequences-including the impact on neurological recovery and contribution to vascular cognitive impairment-association with possible causal processes such as microglial activation, and preventability of SNL.

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Objectives-In major cerebral arterial occlusive diseases, patients with inadequate blood supply relative to metabolic demand (misery perfusion) may be at increased risk for cerebral ischaemia. This study investigated whether patients showing misery perfusion on PET have a high risk of recurrent ischaemic stroke. Methods-The relation between the regional haemodynamic status of cerebral circulation and the subsequent risk of recurrent stroke was prospectively evaluated in 40 patients with symptomatic internal carotid or middle cerebral arterial occlusive diseases who underwent PET. Patients were divided into two haemodynamic categories according to the mean hemispheric value of oxygen extraction fraction in the hemisphere supplied by the artery with symptomatic disease: patients with normal oxygen extraction fraction and those with increased oxygen extraction fraction (misery perfusion). All patients were followed up for at least 12 months. Results-The one year incidence of ipsilateral ischaemic strokes for patients with normal oxygen extraction fraction and those with increased oxygen extraction fraction were two of 33 and four of seven patients respectively. A significantly higher incidence of ipsilateral strokes was found in patients with increased oxygen extraction fraction (Fisher's exact test; P = 0-005). In patients with increased oxygen extraction fraction, three of four strokes were watershed infarctions and the location of the infarction corresponded with the area of increased oxygen extraction fraction. Conclusion-These findings contradict conclusions of a previous study and suggest that patients with major cerebral arterial occlusive diseases and misery perfusion have a high risk for recurrent ischaemic stroke.(C Neurol Neurosurg Psychiatry 1996;61:18-25) Keywords: cerebrovascular disease; computed tomography; haemodynamics; stroke riskIn patients with major cerebral arterial occlusive disease, an inadequate blood supply relative to metabolic demand (misery perfusion)' may increase the risk of cerebral ischaemia, suggesting that identification and optimal treatment of patients with misery perfusion could help prevent stroke. However, it remains unclear whether patients with misery perfusion on PET have a high risk of ischaemic stroke, especially strokes of haemodynamic origin. Although case reports and retrospective studies have indicated that bypass surgery relieved patients with misery perfusion from abnormal haemodynamic state and recurring transient ischaemic attacks,'3' few studies have systematically investigated the relation between cerebral haemodynamics determined by PET and the subsequent risk of stroke. A previous longitudinal study did not find a relation between abnormal cerebral haemodynamics and the subsequent occurrence of stroke,5 but the data of the study were limited and not conclusive because of the few patients studied.2 To further investigate whether patients with misery perfusion have a high risk of recurrent ischaemic stroke, we prospectively followed up 40 medically tre...

Neuropsychological tests that require shifting an attentional set, such as the Wisconsin Card Sorting Test, are sensitive to frontal lobe damage. Although little information is available for humans, an animal experiment suggested that different regions of the prefrontal cortex may contribute to set shifting behavior at different levels of processing. Behavioral studies also suggest that set shifting trials are more time consuming than non-set shifting trials (i.e. switch cost) and that this may be underpinned by differences at the neural level. We determined whether there were differential neural responses associated with two different levels of shifting behavior, that of reversal of stimulus-response associations within a perceptual dimension or that of shifting an attentional set between different perceptual dimensions. Neural activity in the antero-dorsal prefrontal cortex increased only in attentional set shifting, in which switch costs were significant. Activity in the postero-ventral prefrontal cortex increased not only in set shifting but also in reversing stimulus-response associations, in which switch costs were absent. We conclude that these distinct regions in the human prefrontal cortex provide different levels of attention control in response selection. Thus, the antero-dorsal prefrontal cortex may be critical for higher order control of attention, i.e. attentional set shifting, whereas the postero-ventral area may be related to a lower level of shift, i.e. reorganizing stimulus-response associations.