Growth, etching morphology and spectra of LiAlO2 crystal

gamma-LiAlO2 single crystal was successfully grown by Czochralski method. The crystal quality was characterized by X-ray rocking curve and chemical etching. The effects of air-annealing and vapor transport equilibration (VTE) on the crystal quality, etch pits and absorption spectra of LiAlO2 were also investigated in detail. The results show that the as-grown crystal has very high quality with the full width at half maximum (FWHM) of 17.7-22.6 arcsec. Dislocation density in the middle part of the crystal is as low as about 3.0 x 10(3) cm(-2). The VTE-treated slice has larger FWHM value, etch pits density and absorption coefficient as compared with those of untreated and air-annealed slices, which indicates that the crystal quality became inferior after VTE treatment. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interaction between the 5-HT system and the basal ganglia: functional implication and therapeutic perspective in Parkinson's disease

The neurotransmitter serotonin (5-HT) has a multifaceted function in the modulation of information processing through the activation of multiple receptor families, including G-protein-coupled receptor subtypes (5-HT1, 5-HT2, 5-HT4-7) and ligand-gated ion channels (5-HT3). The largest population of serotonergic neurons is located in the midbrain, specifically in the raphe nuclei. Although the medial and dorsal raphe nucleus (DRN) share common projecting areas, in the basal ganglia (BG) nuclei serotonergic innervations come mainly from the DRN. The BG are a highly organized network of subcortical nuclei composed of the striatum (caudate and putamen), subthalamic nucleus (STN), internal and external globus pallidus (or entopeduncular nucleus in rodents, GPi/EP and GPe) and substantia nigra (pars compacta, SNc, and pars reticulata, SNr). The BG are part of the cortico-BG-thalamic circuits, which play a role in many functions like motor control, emotion, and cognition and are critically involved in diseases such as Parkinson's disease (PD). This review provides an overview of serotonergic modulation of the BG at the functional level and a discussion of how this interaction may be relevant to treating PD and the motor complications induced by chronic treatment with L-DOPA.

Laser-induced damage morphology of high-reflective optical coatings

Two different kinds of 1064 nm high-reflective (HR) coatings, with and without SiO2 protective layer, were prepared by electron beam evaporation. Three-dimensional damage morphology, caused by a Nd:YAG pulsed laser, was investigated for these HR coatings. Development of laser-induced damage on HR coatings was revealed by both temperature field calculation and discrete meso-element simulation. Theoretical results met experimental very well. (C) 2004 Elsevier B.V. All rights reserved.

Laser conditioning of ZrO2 : Y2O3/SiO2 mirror coatings prepared by E-beam evaporation

Laser conditioning effects of the dielectric mirror coatings with different designs were investigated. Simple quarter-wave ZrO2:Y2O3/SiO2 mirrors and half-wave SiO2 over-coated ZrO2:Y2O3/SiO2 mirror coatings were fabricated by E-beam evaporation (EBE). The absorbance of the samples before and after laser conditioning was measured by surface thermal lensing (STL) technology and the defects density was detected under Nomarski microscope. The enhancement of the laser damage resistance was found after laser conditioning. The dependence of the laser conditioning on the coating design was also observed and the over-coated sample obtained greatest enhancement, whereas the absorbance of the samples did not change obviously. During the sub-threshold fluence raster scanning, the minor damage about defects size was found and the assumption of pre-damage mechanism, based on the functional damage concept, was put forward. The improvement of the laser induced damage threshold (LIDT) was attributed to the benign damage of the defects and the dependence on the coating design owed to the damage growth behavior of different coating designs. (C) 2004 Elsevier B.V. All rights reserved.

Surface morphology and properties of zirconia thin films prepared at different deposition rates

ZrO2 thin films were prepared on BK7 glass substrates by electron beam evaporation deposition method. The influence of deposition rate varying from 1.2 to 6.3 nm s(-1) on surface morphology and other properties of ZrO2 films were examined. With increasing deposition rate, the surface defect density increased. The decrease in half width at full maximum in X-ray diffraction pattern with deposition rate indicates an increase in crystal dimension with increasing deposition rate. Electron beam deposited ZrO2 films are known to be inhomogeneous. From the change of the peak transmittance value, it can be deduced that the inhomogeneity of ZrO2 films strengthened gradually with increasing deposition rate. The type of surface defects changed from nodules to craters when the deposition rate was high enough.

The use of otolith morphology to indicate the stock structure of common coral trout (Plectropomus leopardus) on the Great Barrier Reef, Australia

We investigated the use of otolith morphology to indicate the stock structure of an exploited serranid coral reef fish, Plectropomus leopardus, on the Great Barrier Reef (GBR), Australia. Otoliths were measured by traditional one-and two-dimensional measures (otolith length, width, area, perimeter, circularity, and rectangularity), as well as by Fourier analysis to capture the finer details of otolith shape. Variables were compared among four regions of the GBR separated by hundreds of kilometers, as well as among three reefs within each region, hundreds of meters to tens of kilometers apart. The temporal stability in otolith structure was examined by comparing two cohorts of fully recruited four-year-old P. leopardus collected two years before and two years after a signif icant disturbance in the southern parts of the GBR caused by a large tropical cyclone in March 1997. Results indicated the presence of at least two stocks of P. leopardus, although the structure of each stock varied depending on the cohort considered. The results highlight the importance of incorporating data from several years in studies using otolith morphology to discriminate temporary and possibly misleading signals from those that indicate persistent spatial structure in stocks. We conclude that otolith morphology can be used as an initial step to direct further research on groups of P. leopardus that have lived at least a part of their life in different environments.