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41.
The wide use of barium (Ba), cesium (Cs), antimony (Sb) and tungsten (W) in many industrial and agricultural fields causes the increased release of these metals into the environment, laying the basis for health risk. To assess the exposure for the general population, the development of adequate and reliable analytical techniques becomes compulsory. This study refers to the quantification of urinary Ba, Cs, Sb and W levels by both quadrupole (Q) and sector field (SF) inductively coupled plasma mass spectrometry (ICP-MS). The two procedures were compared for their performances and their measurement uncertainties. The limits of detection were (Q and SF) 23.0 and 5.21 ng L(-1) for Ba; 21.1 and 7.52 ng L(-1) for Cs; 1.09 and 0.43 ng L(-1) for Sb; and 0.36 and 0.49 ng L(-1) for W. The trueness was better than 93.3% and the precision less than 12% for both techniques. Relative expanded uncertainties of the analytical procedures, at the median levels found in the general population, were below 5% for all the elements with both ICP-MS techniques. The uncertainties related to the calibration and repeatability were the parameters most influencing the final analytical performance. The urinary median values observed in healthy subjects from central Italy were 1146, 4301, 60.8 and 48.5 ng L(-1) for Ba, Cs, Sb and W, respectively.  相似文献   
42.
The structure of the silk from cocoons of two common spiders, Araneus diadematus (family Araneidae) and Achaearanea tepidariorum (family Theridiidae) was investigated by means of (13)C solid state NMR and FT-IR spectroscopies. The combined use of these two techniques allowed us to highlight differences in the two samples. The cocoon silk of Achaearanea tepidariorum is essentially constituted by helical and beta-sheet structures, whereas that of Araneus diadematus shows a more complex structure, containing also beta-strands and beta-turns. Moreover, the former silk is essentially crystalline while the latter contains more mobile domains. The structural differences of the two cocoon silks are ascribed to the different habitat of the two species.  相似文献   
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Sunto Nell'ambito della teoria dell'informazione senza probabilità, si propone una definizione assiomatica dell'informazione associata ad esperienze incomplete. Si discutono in particolare le proprietà del guadagno di informazione e dell'informazione condizionale, giungendo a caratterizzare con un sistema di equazioni funzionali la classe delle misure di informazione che soddisfano agli assiomi adottati; come caso particolare si ottiene la classica misura di Shannon-Rényi. Lavoro eseguito per la realizzazione del programma del gruppo di ricerca n. 7 del C. N. R.  相似文献   
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Lavoro eseguito per la realizzazione del programma del gruppo di ricerca n. 20 del C.N.R. (1960–61).  相似文献   
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Accreditation and Quality Assurance - Unfortunately, figure 3 was incorrectly published in the original publication and the correct version is updated here.  相似文献   
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Journal of Thermal Analysis and Calorimetry - An ever-increasing concern about environmental pollution has spearheaded research into alternative biodegradable polymers. Currently, poly(lactic acid)...  相似文献   
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Harmonic and Cartan decompositions are used to prove that there are eight symmetry classes of elasticity tensors. Recent results in apparent contradiction with this conclusion are discussed in a short history of the problem.Research supported by GNFM of CNR (Italy)  相似文献   
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