Segregation, precipitation and wetting of tilt grain boundaries in molybdenum

The intrinsic structure of different tilt grain boundaries in bcc molybdenum is determined by electron microscopy and compared to the ones obtained after an annealing treatment of the same boundaries in presence of different impurities like carbon and nickel. Specially grown bicrystals with tilt axes parallel to [ 001] and [ 011] are used. The boundaries correspond to the major coincidence relationships Sigma = 5, Sigma = 3 and Sigma = 11. Their experimental atomic structure is compared to calculated ones. After the treatments in presence of carbon or nickel the new structure is determined by electron microscopy from the structural and chemical aspect. After a treatment in presence of carbon the Sigma = 5[001]{310} boundary contains either a segregation or a very thin precipitate layer of a new MoCx quadratic phase. In presence of nickel, the physical phenomenon is possibly a wetting of the boundary. The different [011] tilt boundaries have a different behavior according to their respective energy

High-resolution and conventional electron microscopy study of a Sigma=3, [101]{121} twin grain boundary in molybdenum

Complete structural analysis of a Mo bicrystal containing a Sigma =3, [101](1 (2) over bar1)(A) grain boundary (GB) was achieved by means of transmission electron microscopy from the microscopic to the nanoscopic level. Secondary GB dislocations compensating a small deviation from the exact Sigma =3 concidence were observed and their character was determined. Rigid-body displacements (RBDs) were determined directly from high-resolution electron microscopy images using samples with surface normal parallel and perpendicular to the tilt axis. Measured values of RBDs are compared with recent theoretical calculations

Mitochondrial Haplogroup X is associated with successful aging in the Amish

Avoiding disease, maintaining physical and cognitive function, and continued social engagement in long-lived individuals describe successful aging (SA). Mitochondrial lineages described by patterns of common genetic variants (“haplogroups”) have been associated with increased longevity in different populations. We investigated the influence of mitochondrial haplogroups on SA in an Amish community sample. Cognitively intact volunteers aged ≥80 (n=261) were enrolled in a door-to-door survey of Amish communities in Indiana and Ohio. Individuals scoring in the top third for lower extremity function, needing little assistance with self-care tasks, having no depression symptoms, and expressing high life satisfaction were considered SA (n=74). The remainder (n=187) were retained as controls. These individuals descend from 51 matrilines in a single 13 generation pedigree. Mitochondrial haplogroups were assigned using the 10 mitochondrial single nucleotide polymorphisms (mtSNPs) defining the nine most common European haplogroups. An additional 17 mtSNPs from a genome-wide association panel were also investigated. Associations between haplogroups, mtSNPs, and SA were determined by logistic regression models accounting for sex, age, body mass index, and matriline via generalized estimating equations. SA cases were more likely to carry Haplogroup X (OR=7.56, p=0.0015), and less likely to carry Haplogroup J (OR=0.40, p=0.0003). Our results represent a novel association of Haplogroup X with SA and suggest that variants in the mitochondrial genome may promote maintenance of both physical and cognitive function in older adults