Determination of traces of heavy metals (Mn, Cu, Zn, Cd and Pb) in microsamples of teeth material by ETV-ICP-MS

Heavy metal levels in tooth compartments would appear to be a suitable indicator of long-term exposure. A method has been developed to assess the heavy metal levels (Mn, Cu, Zn, Cd and Pb) in tooth compartments like dentin and enamel. For the simultaneous determination of these elements in small dentin sample amounts (in some cases less than 1 mg) inductively coupled plasma mass spectrometry with electrothermal vaporization was the method of choice. Sample preparation, method development and first results of the application of the method for the analysis of tooth compartments have been described. Variation in the elemental concentrations depending on the kind of tooth and the sampling position have been observed. The method is useful for epidemiological studies of the heavy metal exposure of children.     

Selective and uniform laser-induced failure of antireflection-coated LiNbO3surfaces

LiNbO3surfaces with different antireflection coatings and from different vendors were damaged with 1.06 μm 9.5 ns full width at half maximum laser pulses. By probing with a laser spot smaller than the separation of isolated surface defects, it was possible to separate uniform damage, which was characteristic of the coating itself, from premature defect-driven localized failures. Uniform failure modes were identified and thresholds extracted for each by multithreshold analysis. Frequency of defect damage was determined at several fluences much lower than required for uniform failure. It is likely that defect-driven selective failures reduce the apparent damage threshold of flood-loaded samples. Tentative identification of a selective damage threshold was made and correlated with large-spot multimode test results. Incorporation of these results into a product-improvement program has resulted in LiNbO3Q-switches with increased resistance to selective damage.     

Different adsorption behaviors of methane and carbon dioxide in the isotypic nanoporous metal terephthalates MIL-53 and MIL-47

A distinct step in the isotherm occurs during the adsorption of CO2 on MIL-53 at 304 K. Such behavior is neither observed during the adsorption of CH4 on MIL-53 nor during the adsorption on the isostructural MIL-47. This phenomenon seems to be due to a different mechanism than that of previous adsorption steps on MOF samples. It is suggested that a breathing behavior is induced in MIL-53 during CO2 adsorption.