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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Grundämnes-distribuering och bendensitet : En XRF-undersökning av vikingatida och medeltida lårben från fyra arkeologiska lokaler / Elemental Distribution and Bone Density : an Analysis with μXRF-spectroscopy of Femur from four Archaeological Sites in Sweden dated Viking Age – Middle Ages

Ytterman, Caroline January 2014 (has links)
This essay focuses on developing non-destructive methods to investigate the relationship between elemental distribution and bone porosity in archaeological bone. The skeletal material, which was analyzed, came from the archaeological sites of Skara (county of Västergötland), Varnhem (county of Västergötland), Sigtuna (county of Uppland) and Kopparsvik (county of Gotland). The essay is based on the results of a previous project, Osteoporosis och osteoarthritis, då och nu (Sten 2012). That project aimed at establishing whether medieval people, buried on the above mentioned archaeological sites, were suffersing from osteoporosis and/or osteoarthritis. This knowledge might help the medical research of today to solve the problem of possibly preventing those bone diseases. The method used was DXA-scanning, which was developed for examine osteoporosis in bone from living people. The result showed that the skeletons from the Skara site had an increased bone mineral density (BMD) compared to the skeletons from the other three sites. This essay investigates why these skeletal remains have a higher BMD and how this affects the results of methods like DXA. In this bachelor project various X-ray instruments were used to analyze the BMD of the skeletal remains. The X-ray pictures were then modified to exhibit high and low density areas in the bone. The elemental distribution of the surface area of the neck of the femur was examined with a μXRF-spectrometer. As a complement to the μXRF-spectrometer a SEM (scanning electron microscope) was used to analyze the elemental distribution of a cross section of the femur neck. Soil samples were collected from Skara and Varnhem and analyzed by using μXRF-spectrometry to find out if there was a correlation between the elemental content of the bone and surrounding soil. The skeletal remains from Skara exhibited increased values of iron and manganese combined with higher bone density. The soil from Skara showed a high level of particularly iron. This could be the reason for the increased BMD of the individuals from Skara when using the DXA-analysis. It is likely that, in each archaeological site, iron and manganese ions have diffused from both ground water and soil into the bones and thus increased the BMD. This is especially notified of the skeletal remains of Skara.
2

Exploring the Extent of Phosphorus and Heavy Metal Uptake by Single Cells of Saccharomyces cerevisiae and Their Effects on Intrinsic Elements by SC-ICP-TOF-MS

Quin, Wen, Stärk, Hans-Joachim, Müller, Susann, Reemtsma, Thorsten 07 June 2023 (has links)
The effect of six heavy metals, namely, silver (Ag), lead (Pb), palladium (Pd), copper (Cu), nickel (Ni), and chromium (Cr), on phosphorus (P) uptake by yeast was investigated by single-cell analysis using inductively coupled plasma time-of-flight mass spectrometry (SC-ICP-TOF-MS). It was found that the P content in cells with 1.55 g L1 P feeding after P starvation was increased by 70% compared to control cells. Heavy metals at 10 ppm, except Cu, had a negative impact on P accumulation by cells. Pd reduced the P content by 26% in single cells compared to control cells. Metal uptake was strongest for Ag and Pd (0.7 1012 L cell1) and weakest for Cr (0.05 1012 L cell1). Exposure to Cr markedly reduced (50%) Mg in cells and had the greatest impact on the intrinsic element composition. The SC-ICP-TOF-MS shows the diversity of elemental content in single cells: for example, the P content under standard conditions varied between 12.4 and 890 fg cell1. This technique allows studying both the uptake of elements and sublethal effects on physiology at a single-cell level.
3

Analýza zubů a kostí metodou spektroskopie laserem buzeného plazmatu / Analysis of teeth and bones by laser-induced breakdown spectroscopy

Šindelářová, Anna January 2021 (has links)
The presented diploma thesis deals with the elemental composition of hard tissues – human and murine jaws studied by laser-induced plasma spectroscopy (LIBS). Samples of human teeth contained a disease called ankylosis and the difference in elemental composition of healthy and diseased tissue was observed to localize ankylosis in the tooth. When evaluating the map of the spatial distribution of phosphorus and calcium, a decrease in the concentration of these elements in the ankylosis infected area was observed. Furthermore, murine jaws containing lead were analyzed. When assessing the spatial distribution of lead in tissue, it was found that lead was incorporated in murine teeth in the enamel at the tip of the incisor and molars. In conclusion, LIBS method achieved good results considering the detection of the elemental distribution of hard tissues. It enables to differentiate parts of the tooth in terms of elemental composition and tissue hardness and also to detect changes in the matrix caused by a disease or bioaccumulation of heavy metals.

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