However, youth with ADHD showed find more greater activation in the left dorsolateral prefrontal cortex (DLPFC) and left posterior cingulate cortex (PCC), greater functional

connectivity between the left DLPFC and left intraparietal sulcus, and reduced left DLPFC connectivity with left midcingulate cortex and PCC for the high load contrast compared to controls (p smaller than .01; k bigger than 100 voxels). Reanalysis using a more conservative statistical approach (p smaller than .001; k bigger than 100 voxels) yielded group differences in PCC activation and DLPFC-midcingulate connectivity. Conclusion: Youth with ADHD show decreased efficiency of DLPFC for high-load visuospatial working memory and greater reliance on posterior spatial attention circuits to store and update spatial 432 position than healthy control youth. Findings should be replicated in larger samples.”
“About 2000 tons of chrysotile is used annually to produce friction materials in Islamic MEK inhibitor Republic

of Iran. Approximately, 3000 workers are exposed to the asbestos fibers in the different processes of brake and clutch manufacturing. In the current study, asbestos fiber concentrations during brake and clutch manufacture were measured. This study also evaluated the fiber size and morphology distribution according to the Asbestos International Association (AIA) for standardization analytical method for asbestos.\n\nThe airborne asbestos fiber concentrations selleck chemical and its chemical composition of 92 personal samples were analyzed by phase contrast microscopy (PCM)

and scanning electron microscope (SEM) equipped with an energy-dispersive X-ray analyzer (EDX).\n\nPersonal monitoring of fiber levels demonstrated counts that ranged from 0.31 to 1.3 PCM f/ml ( 15.5-51.5 SEM f/ml). Geometric means of the asbestos concentrations were 1.3 PCM f/ml (51.5 SEM f/ml) and 0.86 PCM f/ml (42.1 SEM f/ml) according to the brake weighting and mixing and clutch mixing process, respectively. The geometrical mean concentrations were 0.63 PCM f/ml (31 SEM f/ml), which is considerably higher than threshold limit value (TLV) of the American Conference of Governmental Industrial Hygienists (ACGIH) which is 0.1 f/ml. The SEM data demonstrate that the fibrous particles consisted, approximately, of chrysotile (50%), tremolite (30%), and actinolite (20%).\n\nBased on these findings, the 50% of airborne fibers inhaled by the workers were amphiboles asbestos with fibers equal and greater than 5 mu m in length and 0.2 mu m in diameter, and thus not included in the PCM-based fiber counts. Therefore, it might be expected that workers who worked in the brake and clutch manufacture will suffer from negative health effects of exposing to the amphibole asbestos fibers. (C) 2009 Elsevier Inc. All rights reserved.