For zero temperature we calculate the mobility as function of the electron density for remote charged-impurity scattering and we take into account exchange-correlation effects and multiple-scattering effects. Multiple-scattering effects give rise to a metal-insulator transition at low electron density. Our calculation is in good agreement with experimental results obtained with remote doped SiGe/Si/SiGe quantum wells having electron densities near the metal-insulator transition. We discuss the critical density of the metal-insulator transition as function of
the remote doping distance and make some predictions. The single-particle relaxation time and spin-polarization Selleckchem Rigosertib effects are also considered. (C) 2010 American Institute of Physics. [doi:10.1063/1.3482058]“
“Purpose: To explore the ability of whole-body 7.0-T magnetic resonance (MR) imaging to depict differences in aspects
of the cerebral cortex of postmortem human brain specimens with cerebral amyloid beta deposition in connection with Alzheimer disease (AD), Down syndrome, or sporadic or hereditary cerebral amyloid JQ1 angiopathy (CAA) and control brain specimens lacking such deposition.
Materials and Methods: This study was approved by the local institutional review board. In all cases, informed consent was obtained to perform autopsy and to use the tissues for research purposes. T2- and T2*-weighted MR imaging was performed in formalin-fixed samples of brain tissue from six subjects with AD changes, seven with CAA, and five subjects without immunohistochemical evidence of cerebral amyloid beta deposition. All MR images were visually assessed for hypointense foci in and inhomogeneity of the cortex. Sensitivity, specificity, and kappa values of these MR imaging features in the detection of histologic changes were calculated.
Results: High-spatial-resolution 0.3 x 0.3 x 0.3-mm three-dimensional T2*-weighted images revealed hypointense
foci, inhomogeneity of the cortex, or both in all specimens selleck chemicals with brain amyloid beta deposition. These MR imaging features were observed in none of the control specimens.
Conclusion: The finding of postmortem susceptibility-weighted changes in the cerebral cortex of patients with cerebral amyloidosis with a human 7.0-T MR imaging system opens up the possibility of obtaining in vivo radiologic evidence of cerebral amyloid beta deposition. (C) RSNA, 2009″
“Purpose: A prospective randomized controlled trial was performed in elderly patients with benign prostatic hyperplasia (BPH) to evaluate the clinical effectiveness of channel transurethral resection of the prostate (C-TURP) combined with an interstitial laser coagulation (ILC) technique during a 4-year follow-up period. Methods: A total of 150 consecutive BPH patients were randomized to an ILC+C-TURP group (n = 50), an ILC group (n = 50) and a TURP group (n = 50).