Transversal ultrahigh-resolution polarizationsensitive optical coherence tomography for strain mapping in materials.

Optical coherence tomography (OCT) and its extension, polarization-sensitive (PS-)OCT, are techniques for contactless and nondestructive imaging of internal structures. In this work, we apply PS-OCT for material characterization. We use a transversal scanning, ultra-high resolution (UHR-)PS-OCT setup providing cross-sectional as well as inplane information about the internal microstructure, the birefringence and the orientation of the optical axis within the material. We perform structural analysis and strain-mapping for different samples: we show the necessity of UHR imaging for a highly strained elastomer sample, and we discuss the effect of large birefringence on the PS-OCT images. Furthermore, we investigate high-aspect ratio photoresist moulds for the production of microelectromechanical parts (MEMS), demonstrating that transversal UHR-PSOCT is a promising tool for non-destructive strain-mapping.

[Blood lead and blood cadmium concentrations in 55-66-year-old women fron different areas of Nordrhein-Westfalen--chronological trends during 1982-1988]. / Blutblei- und Blutcadmiumkonzentrationen bei 55-66jährigen Frauen aus verschiedenen Gebieten Nordrhein-Westfalens--Entwicklungstrends 1982-1988.

Blood lead levels were determined in 3098 55-66 year-old women living in different areas of Northrhine-Westphalia (F.R.G.). Blood cadmium levels were determined in a subgroup of 2538 women. The studies were performed between 1982 and 1988. The results show that there has been a further fall of blood lead levels in the general population of West-Germany since the CEC blood lead surveys of 1979 and 1981. A comparable reduction of blood cadmium was not noted. Residents of large urban agglomerations had, on average, slightly higher blood lead levels than residents of small cities located in rural areas (+0.2-0.5 microgram/dl). With regard to blood cadmium, no differences were seen. Smokers were found to have, on average, 3-4 times higher blood cadmium levels than non-smokers. Blood lead was also elevated in smokers when compared to non-smokers. The highest blood lead levels recorded were in the range of 15-30 micrograms/dl. The data further suggest that lead mobilization during conditions of bone demineralization, e.g. in cases of osteoporosis, does not result in toxic blood lead levels in postmenopausal women.

Exposure to lead and cadmium of children living in different areas of north-west Germany: results of biological monitoring studies 1982-1986.

Between 1982 and 1986 several surveys were carried out to determine the levels of lead and cadmium in blood, urine, and shed deciduous teeth (incisors only) of children living in rural, suburban, urban, and industrial areas of North-West Germany. Blood lead (PbB) and blood cadmium (CdB) were measured in about 4000 children. In rural, suburban and urban areas the median PbB levels vary between 5.5 and 7 micrograms/dl, with 98th percentiles varying between 10 and 13 micrograms/dl. The median CdB levels are between 0.1 and 0.2 microgram/dl, with 95th percentiles between 0.3 and 0.4 microgram/l. Children from urban areas have significantly higher PbB levels than children from rural and suburban areas. Regarding CdB no differences could be detected. Children living in areas around lead and zinc smelters, particularly those living very close to the smelters, have substantially increased PbB and CdB levels. Children from lead worker families also have substantially increased PbB and CdB levels. The lead levels in shed milk teeth (PbT) were determined in about 3000 children. In rural, suburban and urban areas the median PbT levels are between 2 and 3 micrograms/g, with 95th percentiles between 4 and 7 micrograms/g. Children from urban areas have significantly higher PbT levels than children from rural and suburban areas. The highest PbT levels (on a group basis) are in children from nonferrous smelter areas. The median levels of lead in urine (PbU) are between 6 and 10 micrograms/g creatinine, with 95th percentiles between 20 and 30 micrograms/g creatinine. Children from polluted areas have higher PbU levels than children from less polluted areas. The median levels of cadmium in urine (CdU) are in the order of 0.1 microgram/g creatinine, with 95th percentiles being in the range of 0.5 and 1.0 microgram/g creatinine. Girls have higher CdU levels than boys. There are no differences between groups of children from different areas. Children from lead worker families have higher PbU and CdU levels than otherwise comparable children. The results of the present studies indicate a further decrease of PbB in children from North-West Germany since the CEC blood lead campaigns carried out in 1979 and 1981. The decrease of lead exposure also seems to be reflected by a decrease of tooth lead levels.