Gender and age differences in the recurrence of sickness absence due to common mental disorders: a longitudinal study

Background: Common mental disorders (CMDs) are an important cause of sickness absence and long-term work disability. Although CMDs are known to have high recurrence rates, little is known about the recurrence of sickness absence due to CMDs. The aim of this study was to investigate the recurrence of sickness absence due to CMDs, including distress, adjustment disorders, depressive disorders and anxiety disorders, according to age, in male and female employees in the Netherlands. Methods: Data on sickness absence episodes due to CMDs were obtained for 137,172 employees working in the Dutch Post and Telecommunication companies between 2001 and 2007. The incidence density (ID) and recurrence density (RD) of sickness absence due to CMDs was calculated per 1000 person-years in men and women in the age-groups of < 35 years, 35-44 years, 45-54 years, and >= 55 years. Results: The ID of one episode of CMDs sickness absence was 25.0 per 1000 person-years, and the RD was 76.7 per 1000 person-years. Sickness absence due to psychiatric disorders (anxiety and depression) does not have a higher recurrence density of sickness absence due to any CMDs as compared to stress-related disorders (distress and adjustment disorders): 81.6 versus 76.0 per 1000 person-years. The ID of sickness absence due to CMDs was higher in women than in men, but the RD was similar. Recurrences were more frequent in women < 35 years and in women between 35 and 44 years of age. We observed no differences between age groups in men. Recurrences among employees with recurrent episodes occurred within 3 years in 90% of cases and the median time-to-onset of recurrence was 11 (10-13) months in men and 10 (9-12) months in women. Conclusions: Employees who have been absent from work due to CMDs are at increased risk of recurrent sickness absence due to CMDs and should be monitored after they return to work. The RD was similar in men and in women. In women < 45 years the RD was higher than in women >= 45 years. In men no age differences were observed

Gray matter heterogeneity in Asperger syndrome assessed by MR texture analysis and its impact on regional gray matter volume

Brain imaging studies contribute to the neurobiological understanding of Autism Spectrum Conditions (ASC). Herein, we tested the prediction that distributed neurodevelopmental abnormalities in brain development impact on the homogeneity of brain tissue measured using texture analysis (TA; a morphological method for surface pattern characterization). TA was applied to structural magnetic resonance brain scans of 54 adult participants (24 with Asperger syndrome (AS) and 30 controls). Measures of mean gray-level intensity, entropy and uniformity were extracted from gray matter images at fine, medium and coarse textures. Comparisons between AS and controls identified higher entropy and lower uniformity across textures in the AS group. Data reduction of texture parameters revealed three orthogonal principal components. These were used as regressors-of-interest in a voxelbased morphometry analysis that explored the relationship between surface texture variations and regional gray matter volume. Across the AS but not control group, measures of entropy and uniformity were related to the volume of the caudate nuclei, whereas mean gray-level was related to the size of the cerebellar vermis. Similar to neuropathological studies, our study provides evidence for distributed abnormalities in the structural integrity of gray matter in adults with ASC, in particular within corticostriatal and corticocerebellar networks. Additionally, this in-vivo technique may be more sensitive to fine microstructural organization than other more traditional magnetic resonance approaches and serves as a future testable biomarker in AS and other neurodevelopmental disorders

Nanocatalysis I: Synthesis of Metal and Bimetallic Nanoparticles and Porous Oxides and Their Catalytic Reaction Studies

In recent heterogeneous catalysis, much effort has been made in understanding how the size, shape, and composition of nanoparticles and oxide-metal interfaces affect catalytic performance at the molecular level. Recent advances in colloidal synthetic techniques enable preparing diverse metallic or bimetallic nanoparticles with well-defined size, shape, and composition and porous oxides as a high surface support. As nanoparticles become smaller, new chemical, physical, and catalytic properties emerge. Geometrically, as the smaller the nanoparticle the greater the relative number of edge and corner sites per unit surface of the nanoparticle. When the nanoparticles are smaller than a critical size (2.7 nm), finite-size effects such as a change of adsorption strength or oxidation state are revealed by changes in their electronic structures. By alloying two metals, the formation of heteroatom bonds and geometric effects such as strain due to the change of metal-metal bond lengths cause new electronic structures to appear in bimetallic nanoparticles. Ceaseless catalytic reaction studies have been discovered that the highest reaction yields, product selectivity, and process stability were achieved by determining the critical size, shape, and composition of nanoparticles and by choosing the appropriate oxide support. Depending on the pore size, various kinds of micro-, meso-, and macro-porous materials are fabricated by the aid of structure-directing agents or hard-templates. Recent achievements for the preparation of versatile core/shell nanostructures composing mesoporous oxides, zeolites, and metal organic frameworks provide new insights toward nanocatalysis with novel ideas.close