Home About us Contact
|
Home About us Contact | ||
|
|
||
Activation Analysis (activation + analysis)
Kinds of Activation Analysis Selected AbstractsCOLD NEUTRON PROMPT GAMMA ACTIVATION ANALYSIS,A NON-DESTRUCTIVE METHOD FOR CHARACTERIZATION OF HIGH SILICA CONTENT CHIPPED STONE TOOLS AND RAW MATERIALS,ARCHAEOMETRY, Issue 1 2008ZS. KASZTOVSZKY Recently, several archaeometrical projects have been started on the prehistoric collection of the Hungarian National Museum. Among the analytical methods applied, non-destructive prompt gamma activation analysis has a special importance. We have also tested the potential of this method on chipped stone tools, with the aim of determining their exact provenance. On the basis of major and trace element components, characterizations of stone tools and their raw materials,silicites (flint, chert, radiolarite and hornstone) as well as volcanites (felsitic porphyry and obsidian),were performed. We discuss some important results concerning each group, as case studies. Compiling the data set of different PGAA analysis series, compositions of 110 samples are reported, including 76 archaeological pieces. In the future, we plan to extend the number of investigated objects in each class. [source] TESTING ASSUMPTIONS OF NEUTRON ACTIVATION ANALYSIS: COMMUNITIES, WORKSHOPS AND PASTE PREPARATION IN YUCATAN, MEXICO,ARCHAEOMETRY, Issue 2 2000D. E. ARNOLD Contemporary pottery and raw materials (N= 170) from three workshops in Ticul, Yucatán, were analysed by neutron activation to test the hypothesis that individual workshops that used their own clay sources could be identified by their pottery. Although the data failed to confirm the hypothesis, the results reinforced previous conclusions about the relationship of local communities of potters to the chemical patterning of pottery made in these communities. [source] Neutron Activation Analyses of ,Falke-Group' Stoneware,ARCHAEOMETRY, Issue 2 2003A. Schwedt Fragments of late medieval highly decorated Falke-group stoneware have been found in excavations all over central and northern Europe. The distribution of the finds points to an origin in Saxony, but the exact centre of production is still unknown. Therefore, a set of samples has been analysed with Neutron Activation and the data compared with Saxon reference groups. The results point to production in a single workshop. The data can be clearly distinguished from all reference groups in our databank. However, the most similar group is that of Zittau, Saxony. Also, one sherd, which is typologically very similar to the Falke group, and which was made in Zittau, suggests that production was based there. [source] Neutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2006,2007GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 4 2008L. Paul Bédard These mature analytical techniques do not show any change in publication level from the previous two years and AAS remains dominant in terms of the number of publications. The last two years have seen fewer technical improvements than in the previous review period. Some interesting papers dealing with uncertainty and quality assurance in INAA were published during 2006,2007. It is suggested that photon activation should be reconsidered because the source of electron accelerators has recently improved. A technique to preconcentrate Se for INAA determination has also been proposed. In the case of AAS, papers on analyte preconcentration continue to be more abundant than those relating to instrumental modification. Sample preparation for AAS is also active and ultrasound-assisted leaching shows some promising applications. There were an unusual number of reviews concerned with AAS and those important to geological samples are cited here. A technique to preconcentrate Cr in water is presented and a new device to determine As and Se is showing some potential uses. Confocal X-ray mapping continues to show interesting developments. One group developed a technique to perform XRF inside an oyster and an interesting application of ,-XRF mapping of sediments is presented. Determination of platinum-group elements (at ,g g1 concentrations) can be carried out very quickly with an improved XRF technique. [source] Determination of Ti, K, Sm and Gd Values in Geological Survey of Japan Reference Materials by Prompt Gamma Neutron Activation AnalysisGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2006Takashi Sano activation neutronique et comptage gamma; GSJ; roches ignées; samarium gadolinium Prompt gamma neutron activation analysis was applied to the determination of the titanium, potassium, samarium and gadolinium contents of nine Geological Survey of Japan (GSJ) reference materials (JB-1, 1a, 2, 3; JA-1, 2, 3; JR-1, 2). Firstly, the values in JB-1 were determined by the standard addition method: pressed powder disks of JB-1 were used for neutron irradiation and gamma-ray measurements, after known quantities of standard reagents had been added. Secondly, the contents of eight other reference materials were determined by comparison methods using JB-1 as the comparative standard. The precision of analyses were obtained by replicate determinations on these samples. The relative standard deviation was generally less than 5%. For most samples, analysed values agreed well (< 5%) with the recommended values. L'analyse par activation neutronique et comptage des particules gamma rapide a été appliquée à la détermination des concentrations en titane, potassium, samarium et gadolinium de neuf matériaux de référence du Service Géologique du Japon (GSJ) : (JB-1, 1a, 2, 3; JA-1, 2, 3; JR-1, 2). Tout d'abord les teneurs dans JB-1 ont été déterminées par la technique de l'addition de standard : des pastilles de poudre compressée de JB-1 ont été irradiées par un flux neutronique puis la mesure des émissions gamma, a été effectuée après que des quantités connues de réactifs standards aient été ajoutées. Ensuite les teneurs dans les huit autres ont été déterminées en utilisant JB-1 comme standard de calibration. La précision des analyses a été déterminée en dupliquant les analyses de ces échantillons. Les déviations standard relatives étaient généralement de moins de 5%. Pour la plupart des échantillons les teneurs déterminées sont en bon accord (< 5%) avec les valeurs recommandées. [source] Neutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2003GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2005L. Paul Bédard This review for the year 2003 deals with three relatively well-established, mature, analytical techniques (neutron activation analysis, atomic absorption spectrometry and X-ray fluorescence spectrometry) that nevertheless remain very important for the characterisation of geological and environmental samples. Developments in neutron activation analysis included modification to the technique in relation to the determination of platinum-group elements, as well as consideration of sample size in ore grade estimation. A considerable body of literature was published on the application of atomic absorption spectrometry in the analysis of environmental samples. Many of these proposed technical and methodological improvements, notably in extraction procedures. X-ray fluorescence spectrometry saw developments in in situ analysis, synchrotron micro-XRF (,-SRXRF) and a confocal X-ray set-up for 3D elemental imaging. XRF technologies were used in the analysis of geological samples, reference materials, glasses, solutes and environmental materials. [source] Neutron Activation Analysis Applied to the Determination of Heavy Metals and Other Trace Elements in Sediments from Sepetiba Bay (RJ), BrazilGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2-3 2001Fàbio Pellegatti analyse par activation neutronique; métaux lourds; éléments en traces; sédiments marins In this work, instrumental neutron activation analysis (INAA) was applied to the determination of the elements As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn in twenty eight bottom sediment samples from Sepetiba Bay, Rio de Janeiro, Brazil. With the concentration data obtained, contour maps were prepared, by using Kriging method, to show the spatial distribution of the studied elements in the Bay. The elements Co, Cr, Cs, Fe, Sc, Ta and Zn showed similar behaviour in the sediments, with higher concentrations along the northern coast of the bay, where the fluvial water inputs are concentrated. The distribution of U, rare earth elements and Ba in the Bay indicates that these elements are not deposited as contaminants. Dans ce travail, les éléments suivants, As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La Lu, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb et Zn ont été analysés par activation neutronique instrumentale dans vingt huit sédiments de fond de la baie de Sepetiba, Rio de Janeiro, Brésil. Par krigeage et à partir des concentrations obtenues, nous avons établi des cartes de la répartition spatiale des éléments étudiés dans la baie. Co, Cr, Cs, Fe, Sc, Ta et Zn ont des comportements similaires dans les sédiments, avec des concentrations plus importantes le long de la côte nord de la baie, oú les apports en eau fluviale sont concentrés. La distribution en U, Terres Rares et Ba indique que ces éléments ne sont pas déposés comme polluants dans la baie. [source] Late Pleistocene and Holocene whale remains (Cetacea) from Denmark and adjacent countries: Species, distribution, chronology, and trace element concentrationsMARINE MAMMAL SCIENCE, Issue 2 2010Kim Aaris-Sørensen Abstract We describe and review the subfossil whale bones (mammalian order Cetacea) material from the southern Scandinavian area, that is, Skagerrak, Kattegat, the inner Danish waters and the southwestern Baltic Sea. Fifteen species were identified from the subfossil records of which all, except for the bowhead whale (Balaena mysticetus), have also been encountered in the modern times. Fifty-one specimens were radiocarbon dated covering 12 of the subfossil species. The dates fell in three distinct clusters with a few specimens before the last glacial maximum (LGM), a large group between LGM and the Pleistocene/Holocene boundary (ca. 17.0,11.7 cal. kyr BP), and another large group from ca. 8.0 cal. kyr BP onward. Seventeen of the radiocarbon dated specimens have been subjected to trace element analysis by Instrumental Neutron Activation Analysis. Cross plots of the concentrations of Fe and Zn, and Fe and Co show that it is possible to distinguish crayfish eaters from fish/squid eaters. This can be used as a novel and independent method for the determination to species of whale remains of otherwise uncertain speciation. [source] THE DATING OF ANCIENT CHINESE CELADON BY INAA AND PATTERN RECOGNITION METHODS,ARCHAEOMETRY, Issue 4 2009GUOXI XIE In 2005, sherds of a special type of ancient Longquan celadon ware were excavated at Maojiawan, in the city of Beijing, China. Although archaeologists agree that these sherds were fired in the period between the Yuan and Ming Dynasties, their specific date is unclear. In order to solve this problem, five other groups of ancient Longquan celadon sherds of known date were selected as reference samples. The elemental body composition of all the sherds was determined by Instrumental Neutron Activation Analysis (INAA). Using the same principles as in provenance research, pattern recognition methods were used to build classification functions to specify the date of the unknown sherds. After analysing the experimental data by discriminant analysis, three classification functions were built. All the unknown sherds were classified as Ming Dynasty. This prediction is well in accordance with the fact that these sherds are similar to other Longquan Ming celadon, and so they should be fired in the same dynasty. This also verified the judgement of the Beijing Institute of Cultural Relics. [source] THE PETROGRAPHY AND CHEMISTRY OF THIN-WALLED WARE FROM AN HELLENISTIC, ROMAN SITE AT SEGESTA (SICILY),ARCHAEOMETRY, Issue 3 2003G. Montana Samples of Roman thin-walled ware from Segesta (northwestern Sicily), dating back to the early Imperial period, were studied by optical microscopy (OM) and Neutron Activation Analysis (NAA). Up to now, this class of Roman fine tableware has only occasionally been evaluated archaeometrically. Nevertheless, numerous production centres are believed to have been simultaneously active in the western Mediterranean area. Petrographic and chemical data seem to be in agreement with the archaeological hypothesis of local manufacture in Segesta for most of the analysed samples, through a comparison with kiln wasters and local raw materials. The effectiveness of thin-section petrography for determining the provenance of such a tiny tempered class of pottery and the integrated use of two different grouping procedures (petrography and chemistry) were also tested. [source] Assessing Ceramic Compositional Data: A Comparison of Total Reflection X-ray Fluorescence and Instrumental Neutron Activation Analysis On Late Iron Age Spanish Celtiberian CeramicsARCHAEOMETRY, Issue 3 2001M. García-Heras A solid-phase, non-chemical processing protocol was recently developed as a means of chemically characterizing archaeological ceramics by total reflection X-ray fluorescence (TXRF). Following this methodology, TXRF can provide semi-quantitative determinations for 18 elements with comparable levels of precision and accuracy for the majority of them in comparison with a clay reference material analysed by instrumental neutron activation (INAA). In order critically to assess the analytical capabilities of TXRF, a large sample set of Late Iron Age Spanish Celtiberian ceramics and modern clays was analysed both by TXRF and INAA. Semi-quantitative chemical data provided by TXRF and quantitative data provided by INAA were subjected to commonly used multivariate statistical methods as a way of evaluating the ability of the new technique to discriminate among different compositional groups. The comparison of the two data sets shows no significant discrepancies, thereby allowing support for the same archaeological interpretation. These results suggest that TXRF has potential applicability for compositional characterization of archaeological ceramics, providing data that are useful for provenance studies. [source] Geochemistry and origin of metal, olivine clasts, and matrix in the Dong Ujimqin Qi mesosideriteMETEORITICS & PLANETARY SCIENCE, Issue 3 2008Ping Kong According to silicate textures and metal composition, this meteorite is classified as a member of subgroup IB. Instrumental neutron activation analyses (INAA) of metals show that the matrix metal has lower concentrations of Os, Ir, Re, and Pt, but higher concentrations of Ni and Au than the 7.5 cm metal nodule present in the meteorite. We attribute these compositional differences to fractional crystallization of molten metal. Studies of olivine clasts show that FeO contents are uniform in individual olivine crystals but are variable for different olivine clasts. Although concentrations of rare earth elements (REEs) change within olivine clasts, they all exhibit a vee-shaped pattern relative to CI chondrites. The relatively high concentrations of REEs in olivine and the shape of REE patterns require a liquid high in REEs and especially in light REEs. As such a liquid was absent from the region where basaltic and gabbroic clasts formed, mesosiderite olivine must have formed in a part of the differentiated asteroid that is different from the location where other mesosiderite silicate clasts formed. [source] Pilot study experiments sourcing quartzite, Gunnison Basin, ColoradoGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2008Bonnie L. Pitblado This paper reports the results of pilot-study efforts to develop methods to profile quartzite, a rock type to which geochemical and other sourcing techniques have only rarely been applied. The long-term goal of the research is to fingerprint sources of quartzite in the Gunnison Basin, southwest Colorado, used by Paleoindian people ca. 11,500,8,000 years ago to make stone tools. Success would facilitate reconstruction of Paleoindian mobility in the Southern Rocky Mountains and potentially anywhere prehistoric people used quartzite. The goals of this paper are more modest: to demonstrate that a small-scale exploration of sourcing techniques suggests reason for optimism that quartzites may be amenable to source discrimination. For the same twenty Gunnison Basin quartzite samples, this study evaluated petrography, ultraviolet fluorescence (UVF), wavelength dispersive X-ray fluorescence (WD-XRF), instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectrometry,both acid-digestion (AD-ICP-MS) and laser ablation (LA-ICP-MS),as means to differentiate among the specimens and the sources they represent. Although more testing is needed to verify and refine our results, the study suggests there is potential for petrography, INAA, and both versions of ICP-MS to discriminate among quartzites from different source localities in the Gunnison Basin. The greatest potential for discriminating among different sources of quartzite in the Gunnison Basin may lie in a methodology combining petrographic analysis and LA-ICPMS. Future testing is required to evaluate this two-fold approach. © 2008 Wiley Periodicals, Inc. [source] Determination of Ti, K, Sm and Gd Values in Geological Survey of Japan Reference Materials by Prompt Gamma Neutron Activation AnalysisGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2006Takashi Sano activation neutronique et comptage gamma; GSJ; roches ignées; samarium gadolinium Prompt gamma neutron activation analysis was applied to the determination of the titanium, potassium, samarium and gadolinium contents of nine Geological Survey of Japan (GSJ) reference materials (JB-1, 1a, 2, 3; JA-1, 2, 3; JR-1, 2). Firstly, the values in JB-1 were determined by the standard addition method: pressed powder disks of JB-1 were used for neutron irradiation and gamma-ray measurements, after known quantities of standard reagents had been added. Secondly, the contents of eight other reference materials were determined by comparison methods using JB-1 as the comparative standard. The precision of analyses were obtained by replicate determinations on these samples. The relative standard deviation was generally less than 5%. For most samples, analysed values agreed well (< 5%) with the recommended values. L'analyse par activation neutronique et comptage des particules gamma rapide a été appliquée à la détermination des concentrations en titane, potassium, samarium et gadolinium de neuf matériaux de référence du Service Géologique du Japon (GSJ) : (JB-1, 1a, 2, 3; JA-1, 2, 3; JR-1, 2). Tout d'abord les teneurs dans JB-1 ont été déterminées par la technique de l'addition de standard : des pastilles de poudre compressée de JB-1 ont été irradiées par un flux neutronique puis la mesure des émissions gamma, a été effectuée après que des quantités connues de réactifs standards aient été ajoutées. Ensuite les teneurs dans les huit autres ont été déterminées en utilisant JB-1 comme standard de calibration. La précision des analyses a été déterminée en dupliquant les analyses de ces échantillons. Les déviations standard relatives étaient généralement de moins de 5%. Pour la plupart des échantillons les teneurs déterminées sont en bon accord (< 5%) avec les valeurs recommandées. [source] Neutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2003GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2005L. Paul Bédard This review for the year 2003 deals with three relatively well-established, mature, analytical techniques (neutron activation analysis, atomic absorption spectrometry and X-ray fluorescence spectrometry) that nevertheless remain very important for the characterisation of geological and environmental samples. Developments in neutron activation analysis included modification to the technique in relation to the determination of platinum-group elements, as well as consideration of sample size in ore grade estimation. A considerable body of literature was published on the application of atomic absorption spectrometry in the analysis of environmental samples. Many of these proposed technical and methodological improvements, notably in extraction procedures. X-ray fluorescence spectrometry saw developments in in situ analysis, synchrotron micro-XRF (,-SRXRF) and a confocal X-ray set-up for 3D elemental imaging. XRF technologies were used in the analysis of geological samples, reference materials, glasses, solutes and environmental materials. [source] Neutron Activation Analysis Applied to the Determination of Heavy Metals and Other Trace Elements in Sediments from Sepetiba Bay (RJ), BrazilGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2-3 2001Fàbio Pellegatti analyse par activation neutronique; métaux lourds; éléments en traces; sédiments marins In this work, instrumental neutron activation analysis (INAA) was applied to the determination of the elements As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn in twenty eight bottom sediment samples from Sepetiba Bay, Rio de Janeiro, Brazil. With the concentration data obtained, contour maps were prepared, by using Kriging method, to show the spatial distribution of the studied elements in the Bay. The elements Co, Cr, Cs, Fe, Sc, Ta and Zn showed similar behaviour in the sediments, with higher concentrations along the northern coast of the bay, where the fluvial water inputs are concentrated. The distribution of U, rare earth elements and Ba in the Bay indicates that these elements are not deposited as contaminants. Dans ce travail, les éléments suivants, As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La Lu, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb et Zn ont été analysés par activation neutronique instrumentale dans vingt huit sédiments de fond de la baie de Sepetiba, Rio de Janeiro, Brésil. Par krigeage et à partir des concentrations obtenues, nous avons établi des cartes de la répartition spatiale des éléments étudiés dans la baie. Co, Cr, Cs, Fe, Sc, Ta et Zn ont des comportements similaires dans les sédiments, avec des concentrations plus importantes le long de la côte nord de la baie, oú les apports en eau fluviale sont concentrés. La distribution en U, Terres Rares et Ba indique que ces éléments ne sont pas déposés comme polluants dans la baie. [source] Preparation and Certification of High-Grade Gold Ore Reference Materials (GAu 19-22)GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2001Tiexin Gu materiau de référence certifié; gisement d 'or,GAu 19-22,IGGE,valeurs certifiées Two types of gold deposit with both good homogeneity and a high-grade of gold were selected to prepare four gold ore reference materials (GAu-19,GAu-20,GAu-21 and GAu-22) by the Institute of Geophysical and Geochemical Exploration (IGGE),China. Seven laboratories participated in the certification programme. Volumetric methods for GAu19-21 and atomic absorption spectrometry for GAu-22 were used for the homogeneity testing,the coefficient of variation being found to be less than 3%. After sample digestion and preconcentration,the samples were analysed by flame atomic absorption spectrometry (AAS),colorimetry,neutron activation analysis (NAA)and volumetric analysis. The certified values for the gold concentration in GAu19-22 are 18.3 ,g g -1, 32.3 ,g g -1, 53.0 ,g g -1 and 5.72 ,g g -1,respectively. Deux types de gisements d'or, présentant à la foisune bonne homogénéité et une teneur élevée en or, ont été sélectionnés par l'Institut d 'Exploration Géophysique et Géochimique de Chine (IGGE)afin de préparer quatre matériaux de référence pour l'or (GAu-19,GAu-20,GAu-21 et Gau-22). Sept laboratoires ont participé au programme de certification. Des méthodes volumétriques (GAu-19-21)et de spectrométrie par absorption atomique (GAu 22)ont été utilisées pour tester l'homogénéité de ces échantillons;les coefficients de variation se sont révélés inférieurs à 3%.Après la mise en solution et la préconcentration des échantillons,ceux-ci ont eté analysés par spectrométrie d 'absorption atomique (AAS), colorimétrie,activation neutronique (NAA)et analyse volumétrique.Les valeurs certifiées pour la concentration en or de GAu19-22 sont respectivement de 18.3 ,g.g -1,32.3 ,g g -1, 53.0 ,g g -1 et 5.72 ,g g -1. [source] Nocturnal nutritional supplementation improves total body protein status of patients with liver cirrhosis: A randomized 12-month trial,HEPATOLOGY, Issue 2 2008Lindsay D. Plank Patients with liver cirrhosis exhibit early onset of gluconeogenesis after short-term fasting. This accelerated metabolic reaction to starvation may underlie their increased protein requirements and muscle depletion. A randomized controlled trial was conducted to test the hypothesis that provision of a late-evening nutritional supplement over a 12-month period would improve body protein stores in patients with cirrhosis. A total of 103 patients (68 male, 35 female; median age 51, range 28,74; Child-Pugh grading: 52A, 31B, 20C) were randomized to receive either daytime (between 0900 and 1900 hours) or nighttime (between 2100 and 0700 hours) supplementary nutrition (710 kcal/day). Primary etiology of liver disease was chronic viral hepatitis (67), alcohol (15), cholestatic (6), and other (15). Total body protein (TBP) was measured by neutron activation analysis at baseline, 3, 6, and 12 months. Total daily energy and protein intakes were assessed at baseline and at 3 months by comprehensive dietary recall. As a percentage of values predicted when well, TBP at baseline was similar for the daytime (85 ± 2[standard error of the mean]%) and nighttime (84 ± 2%) groups. For the nighttime group, significant increases in TBP were measured at 3 (0.38 ± 0.10 kg, P = 0.0004), 6 (0.48 ± 0.13 kg, P = 0.0007), and 12 months (0.53 ± 0.17 kg, P = 0.003) compared to baseline. For the daytime group, no significant changes in TBP were seen. Daily energy and protein intakes at 3 months were higher than at baseline in both groups (P < 0.0001), and these changes did not differ between the groups. Conclusion: Provision of a nighttime feed to patients with cirrhosis results in body protein accretion equivalent to about 2 kg of lean tissue sustained over 12 months. This improved nutritional status may have important implications for the clinical course of these patients. (HEPATOLOGY 2008.) [source] Calcium Accretion in Girls and Boys During Puberty: A Longitudinal AnalysisJOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2000Donald A. Bailey Abstract The primary purpose of this study was to estimate the magnitude and variability of peak calcium accretion rates in the skeletons of healthy white adolescents. Total-body bone mineral content (BMC) was measured annually on six occasions by dual-energy X-ray absorptiometry (DXA; Hologic 2000, array mode), a BMC velocity curve was generated for each child by a cubic spline fit, and peak accretion rates were determined. Anthropometric measures were collected every 6 months and a 24-h dietary recall was recorded two to three times per year. Of the 113 boys and 115 girls initially enrolled in the study, 60 boys and 53 girls who had peak height velocity (PHV) and peak BMC velocity values were used in this longitudinal analysis. When the individual BMC velocity curves were aligned on the age of peak bone mineral velocity, the resulting mean peak bone mineral accrual rate was 407 g/year for boys (SD, 92 g/year; range, 226,651 g/year) and 322 g/year for girls (SD, 66 g/year; range, 194,520 g/year). Using 32.2% as the fraction of calcium in bone mineral, as determined by neutron activation analysis (Ellis et al., J Bone Miner Res 1996;11:843-848), these corresponded to peak calcium accretion rates of 359 mg/day for boys (81 mg/day; 199,574 mg/day) and 284 mg/day for girls (58 mg/day; 171,459 mg/day). These longitudinal results are 27,34% higher than our previous cross-sectional analysis in which we reported mean values of 282 mg/day for boys and 212 mg/day for girls (Martin et al., Am J Clin Nutr 1997;66:611-615). Mean age of peak calcium accretion was 14.0 years for the boys (1.0 years; 12.0-15.9 years), and 12.5 years for the girls (0.9 years; 10.5-14.6 years). Dietary calcium intake, determined as the mean of all assessments up to the age of peak accretion was 1140 mg/day (SD, 392 mg/day) for boys and 1113 mg/day (SD, 378 mg/day) for girls. We estimate that 26% of adult calcium is laid down during the 2 adolescent years of peak skeletal growth. This period of rapid growth requires high accretion rates of calcium, achieved in part by increased retention efficiency of dietary calcium. [source] Gastrointestinal persorption and tissue distribution of differently sized colloidal gold nanoparticlesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2001Julián F. Hillyer Abstract The gastrointestinal uptake of micro- and nanoparticles has been the subject of recent efforts to develop effective carriers that enhance the oral uptake of drugs and vaccines. Here, we used correlative instrumental neutron activation analysis and electron microscopy to quantitatively and qualitatively study the gastrointestinal uptake and subsequent tissue/organ distribution of 4, 10, 28, and 58 nm diameter metallic colloidal gold particles following oral administration to mice. In our quantitative studies we found that colloidal gold uptake is dependent on particle size: smaller particles cross the gastrointestinal tract more readily. Electron microscopic studies showed that particle uptake occurred in the small intestine by persorption through single, degrading enterocytes in the process of being extruded from a villus. To our knowledge this is the first report, at the ultrastructural level, of gastrointestinal uptake of particulates by persorption through holes created by extruding enterocytes. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1927,1936, 2001 [source] Li-Deficient, Off-Congruent MgO:LiNbO3 Crystals Prepared by Postgrown Li-Poor Vapor Transport Equilibration for Integrated OpticsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010De-Long Zhang Li-deficient, off-congruent Z -cut MgO:LiNbO3 (MgO:LN) crystals for integrated optics were prepared by carrying out postgrown Li-poor vapor transport equilibration (VTE) treatments on congruently grown MgO (5 mol% in melt):LiNbO3 plates at 1100°C for durations ranging from 40 to 395 h. Secondary ion mass spectrometry analysis, surface ordinary refractive index measurement, and neutron activation analysis were carried out on the VTE crystals to verify that the Mg and Nb ions did not diffuse out of the crystal during the VTE procedure and their distributions over the whole plate retain its homogeneity. The VTE duration dependence of the Li2O content reduction was determined using gravimetric method, and the crystalline phase was by powder X-ray diffraction. The results show that the Li2O content decreases with a prolonged VTE and the Li2O content reduction in the saturation regime is about 2.9 mol%. All of the VTE crystals still retain the LN phase, and Li-vacancy and NbLi are the major defects in the VTE crystal. OH absorption study reveals that the doped MgO concentration is below the photorefractive threshold for all VTE crystals. The optical absorption edge (OAE) of the VTE-treated MgO:LN was also measured as a function of the VTE duration. On the basis of the known Li2O content and measured OAE, the photon-energy fit reported previously, valid for the evaluation of Li2O content in a pure LN, is corrected for the Li-poor VTE-treated MgO:LNs. Finally, the applicability of the Li-deficient off-congruent MgO:LN crystals prepared by the Li-poor VTE method is demonstrated by characterizing the optical damage and Er diffusion properties of a single-mode Ti:MgO:Er:LiNbO3 strip waveguide fabricated on an Li-poor VTE-prepared MgO:LN crystal. [source] Niobium and tantalum in carbonaceous chondrites: Constraints on the solar system and primitive mantle niobium/tantalum, zirconium/niobium, and niobium/uranium ratioMETEORITICS & PLANETARY SCIENCE, Issue 2 2000K. p. Jochum The abundance of Ta was determined in the same meteorites by radiochemical neutron activation analysis (RNAA). Precision of the MIC-SSMS and RNAA techniques is ,3% and , 5%, respectively. The new abundances for CI chondrites are: Nb = 0.247, Ta = 0.0142, Zr = 3.86, Y = 1.56 ,g/g; or 0.699, 0.0202, 11.2, and 4.64 atoms/106 Si atoms, respectively. The values agree with earlier compilations, but they are a factor of 2 more precise than earlier analyses. Trace element concentrations in the CM, CV, and CK chondrites are higher than in the CI chondrite Orgueil by about 37, 86, and 120%, respectively, in agreement with the variable absolute contents of refractory lithophile elements in different groups of carbonaceous chondrites. Of particular interest are the chondritic Nb/Ta, Zr/Nb, and Nb/U ratios, because these ratios are important tools for interpreting the chemical evolution of planetary bodies. We obtained Nb/Ta = 17.4 ± 0.5 for the carbonaceous chondrites and the Juvinas-type eucrites investigated. Though this value is similar to previous estimates, it is much more precise. The same is true for Zr/Nb (15.5 ± 0.2) and Zr/Y (2.32 ± 0.12). In combination with recently published MIC-SSMS U data for carbonaceous chondrites, we obtained a chondritic Nb/U ratio of 29 ± 2. Because Nb, Ta, Zr, Y, and U are refractory lithophile elements and presumably partitioned into the silicate phase of the Earth during core formation, the elemental ratios may also be used to constrain evolution of the Earth's primitive mantle and, with the more precise determinations fractionation of Nb and Ta during magmatic processes and mantle-crust interactions, can now be interpreted with greater confidence. [source] Bone manganese as a biomarker of manganese exposure: A feasibility studyAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 10 2009-Mili, Ana Pejovi Abstract Background There is a need for a diagnostic tool with the ability to measure cumulative exposure to manganese (Mn) in the workplace. Measuring bone Mn levels with in vivo neutron activation analysis (IVNAA) could serve as a biomarker of past exposure. Bone Mn levels of welders were measured and compared to the levels found in subjects without exposure to the element. Method Forty subjects (30 welders and 10 controls) were recruited. An occupational history was obtained and subjects underwent IVNAA bone Mn measurements. Results The mean bone Mn levels were (2.9,±,0.4) and (0.1,±,0.7),µg Mn/g Ca for welders and controls, respectively (P,<,0.05). Conclusions This project, the first of its kind, reports differences in bone Mn between Mn-exposed welders and non-occupationally exposed subjects. It appears that bone Mn levels do reflect differences in the occupational exposure of welders. Am. J. Ind. Med. 52:742,750, 2009. © 2009 Wiley-Liss, Inc. [source] Analyses of Thick Lithium Coatings Deposited by Sputter-Evaporation and Exposed to AirPLASMA PROCESSES AND POLYMERS, Issue S1 2009C. Rigaux Abstract Lithium coatings on various substrates have numerous applications: Boron neutron capture therapy, neutron activation analysis, super-conducting tokamak etc. Traditionally these coatings are produced by well-known techniques such as electrochemistry and evaporation. In this work, we investigated a new method based on sputter-evaporation, which enables thick coatings (>10,µm) to be built on various substrates within a short timeframe. In order to minimize the process time, evaporation techniques can be used but the coating quality suffers. Moreover, it is well known that the use of DC magnetron sputtering results in the deposition of good quality coatings (smoothness, density, adhesion); however, the deposition rate is low. The rationale of this work is to combine these two techniques, yielding a sputter-evaporation process that possesses the advantages of each separate technique. Li is placed in a stainless steel crucible (cathode), and heated by the plasma generated by a magnetron discharge. The Li temperature is measured by a thermocouple welded onto the cathode and measured at different plasma power densities. The deposition rate of lithium is measured using a quartz balance and by profilometry, at several temperatures (from 0 to 580,°C). Li samples were depth-profiled with the resonant nuclear reaction 7Li(p,,)7. In addition to the concentration, certain characteristics like the density and the chemical reactivity of layers, are also important. Thus we have studied the evolution of the density with time, estimated by weight and profilometry measurements, and the change in morphology, by cross-sectional scanning electron microscopy (SEM), of samples exposed to air at room temperature. The evolution of the film compounds have also been determined by X-ray powder diffraction. These physical properties have been investigated for various bias substrates during deposition. [source] NEW EVIDENCE FOR APULIAN RED-FIGURE PRODUCTION CENTRESARCHAEOMETRY, Issue 5 2010J. THORN A total of 52 South Italian red-figure vases were subjected to neutron activation analysis. The primary aim of the study was to determine whether all Apulian red-figure pottery datable to the period c. 430,340 bc was produced at the Greek colony of Taras, as has been widely assumed. Three chemically distinct compositional groups were isolated and compared to archaeological reference material from Taranto. The results of this comparison suggest that some Early Apulian red-figure pottery may have been produced outside of Taras from the fifth century bc onwards. [source] PARTICLE-INDUCED X-RAY EMISSION (PIXE) ANALYSIS OF OBSIDIAN FROM TEOTIHUACANARCHAEOMETRY, Issue 3 2010J. GAZZOLA A collection of 50 archaeological obsidian samples studied in the framework of the Preciudadela Project (Teotihuacan, Mexico) has been analysed using particle-induced X-ray emission (PIXE) with the external beam line of the Accélérateur Grand Louvre d'Analyse Elémentaire facility (C2RMF, Paris) and of the Instituto de Física (UNAM, Mexico). This work addresses the provenance of these obsidian samples, with the purpose of determining if they come from the obsidian sources exploited by Teotihuacans (mainly Otumba and Sierra de Pachuca), from other sources, or arrived via commercial exchanges with other regions. For that, the elemental compositions derived from the PIXE spectra have been compared with data published in the literature on the basis of instrumental neutron activation analysis. From the concentrations of selected key elements (Na, K, Mn, Fe, Zn, Rb, Sr, Zr), it was possible to unambiguously assign the provenance of most samples. Many originate from two major sources, namely Sierra de Pachuca (Hidalgo) and Otumba (Mexico), which were the main obsidian deposits used by the Teotihuacans. However, some samples exhibit a compositional fingerprint matching other provenances, i.e., Paredón (Puebla) and Zacualtipan (Hidalgo). [source] CHEMICAL CHARACTERIZATION OF TIN-LEAD GLAZED POTTERY FROM THE IBERIAN PENINSULA AND THE CANARY ISLANDS: INITIAL STEPS TOWARD A BETTER UNDERSTANDING OF SPANISH COLONIAL POTTERY IN THE AMERICAS,ARCHAEOMETRY, Issue 4 2009J. G. IÑAÑEZ Majolica pottery was the most characteristic tableware produced in Europe during the Medieval and Renaissance periods. Because of the prestige and importance attributed to this ware, Spanish majolica was imported in vast quantities into the Americas during the Spanish Colonial period. A study of Spanish majolica was conducted on a set of 186 samples from the 10 primary majolica production centres on the Iberian Peninsula and 22 sherds from two early colonial archaeological sites on the Canary Islands. The samples were analysed by neutron activation analysis (NAA), and the resulting data were interpreted using an array of multivariate statistical approaches. Our results show a clear discrimination between different production centres, allowing a reliable provenance attribution of the sherds from the Canary Islands. [source] COLD NEUTRON PROMPT GAMMA ACTIVATION ANALYSIS,A NON-DESTRUCTIVE METHOD FOR CHARACTERIZATION OF HIGH SILICA CONTENT CHIPPED STONE TOOLS AND RAW MATERIALS,ARCHAEOMETRY, Issue 1 2008ZS. KASZTOVSZKY Recently, several archaeometrical projects have been started on the prehistoric collection of the Hungarian National Museum. Among the analytical methods applied, non-destructive prompt gamma activation analysis has a special importance. We have also tested the potential of this method on chipped stone tools, with the aim of determining their exact provenance. On the basis of major and trace element components, characterizations of stone tools and their raw materials,silicites (flint, chert, radiolarite and hornstone) as well as volcanites (felsitic porphyry and obsidian),were performed. We discuss some important results concerning each group, as case studies. Compiling the data set of different PGAA analysis series, compositions of 110 samples are reported, including 76 archaeological pieces. In the future, we plan to extend the number of investigated objects in each class. [source] PETROGRAPHIC AND CHEMICAL CHARACTERIZATION OF POTTERY PRODUCTION OF THE LATE MINOAN I KILN AT HAGHIA TRIADA, CRETE,ARCHAEOMETRY, Issue 4 2007C. M. BELFIORE Pottery from the Late Minoan I kiln at Haghia Triada in the Mesara Plain, southern Crete, was analysed by a range of techniques, comprising thin-section petrography, scanning electron microscopy, X-ray diffraction, X-ray fluorescence and neutron activation analysis. The project characterizes the ceramic fabrics and probable raw materials, correlates paste recipes with shape, reconstructs the firing conditions of the kiln and establishes a chemical reference group, taking into account post-burial alteration and contamination. Comparison of the reference group formed with that from the neighbouring, broadly contemporary, kiln at Kommos shows an unexpected differentiation of the two kilns. [source] THE HISTORY OF THE LAWRENCE BERKELEY NATIONAL LABORATORY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS PROGRAMME FOR ARCHAEOLOGICAL AND GEOLOGICAL MATERIALSARCHAEOMETRY, Issue 2 2007F. ASARO The Lawrence Berkeley National Laboratory pottery provenance group developed standards and instrumental neutron activation analysis (INAA) methods that are used at many archaeometry laboratories around the world. The background and development of ,Standard Pottery' and of methods for INAA are described. Early pottery provenance studies are described, and other research programmes, involving obsidian and magmatic mixing, the origin of the stone used for the Colossi of Memnon, and the ,Plate of Brass', are mentioned. Research work by the Laboratory included the discovery of the world-wide iridium anomaly and extensive subsequent research on what has come to be known as the ,Asteroid Impact Theory'. Characteristics of the analytical programme for pottery provenance work, including overall aims, precision and accuracy, intercalibration, and irradiation and measurement protocols, are discussed. New research areas developed in the past 15 years, to broaden the usefulness of chemical compositional data for archaeological investigation, and examples of recent work, are described. This research, which makes use of high-precision X-ray fluorescence analysis in addition to INAA measurements on sample splits, includes distinguishing the products of different workshops located at the same production site, studies on the significance of the distribution of silver in archaeological pottery and the use of high-precision chemical compositional data as an aid for making chronological distinctions. [source] | ||||||||||||||||||||||