Calcium Isotopes in Human Urine as a Diagnostic Tool for Bone Loss: Additional Evidence for Time Delays in Bone Response to Experimental Bed Rest.

The calcium (Ca) isotopic composition in urine during bed rest has been demonstrated to be systematically light, indicating a negative bone mineral balance (i.e., bone loss).

Using stable isotope fractionation factors to identify Cr(VI) reduction pathways: Metal-mineral-microbe interactions.

Microbes interact with metals and minerals in the environment altering their physical and chemical states, whilst in turn metals and minerals impact on microbial growth, activity and survival. The interactions between bacteria and dissolved chromium in the presence of iron minerals, and their impact on Cr isotope variations, were investigated. Cr(VI) reduction experiments were conducted with two bacteria, Pseudomonas fluorescens LB 300 and Shewanella oneidensis MR-1, in the presence of two iron oxide minerals, goethite and hematite.

A Chinese imprint in insoluble pollutants recently deposited in central Greenland as indicated by lead isotopes.

A unique ∼ 10 year record of the lead isotopic composition of airborne insoluble particulate matter deposited in central Greenland was extracted from recent snow layers at NorthGRIP (75.1°N, 042.3°W; elevation 2,959 m), spanning the years 1989-2001.

Bioavailable 87Sr/86Sr in different environmental samples--effects of anthropogenic contamination and implications for isoscapes in past migration studies.

(87)Sr/(86)Sr reference maps (isoscapes) are a key tool for investigating past human and animal migrations. However, there is little understanding of which biosphere samples are best proxies for local bioavailable Sr when dealing with movements of past populations. In this study, biological and geological samples (ground vegetation, tree leaves, rock leachates, water, soil extracts, as well as modern and archeological animal teeth and snail shells) were collected in the vicinity of two early medieval cemeteries ("Thuringians", 5-6th century AD) in central Germany, in order to characterize (87)Sr/(86)Sr of the local biosphere.