A new model for fatigue damage evolution of polymer matrix composites is presented. The model is based on a combination of an orthotropic damage model and an isotropic fatigue evolution model. The orthotropic damage model is used to predict the orthotropic damage evolution within a single cycle. The isotropic fatigue model is used to predict the magnitude of fatigue damage accumulated as a func...

Chronic exposure to sunlight causes skin cancer in humans, yet little is known about how habitual exposure to low doses of ultraviolet B radiation (UVB) affects DNA damage in the skin. We treated Skh-1 hairless mice with daily doses of suberythemal UVB for 40 days and analyzed the amount and distribution of DNA photodamage using RIAs and immunofluorescence micrography. We found that DNA damage ...

Radiation damage of structural materials leads to mechanical property degradation, eventually inducing failure. Secondary-phase dispersoids or other defect sinks are often added boost their radiation resistance. We demonstrate that a metal composite made by adding 1D carbon nanotubes (CNTs) aluminum (Al) exhibits superior In situ ion irradiation with transmission electron microscopy (TEM) and a...

Studies of the effects of smoking on leukocyte telomere length (LTL) using cigarettes smoked per day or pack years smoked (PYS) present limitations. Reported high levels of smoking may not increase toxin exposure levels proportionally. Nicotine metabolism ratio (NMR) predicts total cigarette puff volume and overall exposure based on total N-nitrosamines, is highly reproducible and independent o...

Mutation frequency and specificity were determined as a function of age in nuclear DNA from liver, bladder, and brain of Big Blue lacI transgenic mice aged 1.5-25 months. Mutations accumulated with age in liver and accumulated more rapidly in bladder. In the brain a small initial increase in mutation frequency was observed in young animals; however, no further increase was observed in adult mic...

Oxidative mechanisms are considered to contribute to the aging changes in retinal pigment epithelial (RPE) cells that underlie the pathogenesis of age-related macular degeneration. An important source of oxidative damage is likely to be the photoreactive pigments that progressively accumulate and constitute the lipofuscin of retinal pigment epithelial cells. Evidence for a link between RPE lipo...

OBJECTIVES To examine bone mineral density (BMD) frequency of osteoporosis and reduced bone mass in systemic lupus erythematosus (SLE), and compare the data of the SLE patients with matched rheumatoid arthritis (RA) patients and healthy controls. Secondly, to study possible correlations between BMD, demographic and disease variables in the SLE patients. METHODS Measures of BMD assessed by dua...