0000000000347434
AUTHOR
Willi Dindorf
Sensitivity of whole wood stable carbon and oxygen isotope values to milling procedures
RATIONALE Milling of wood samples is a widely applied preparation method for pooling tree-rings from different trees or periods of several years for determination of δ13C and δ18O values. In this study, whole wood samples were milled using different procedures in order to evaluate potential effects of this preparation method on δ13C and δ18O values. METHODS Subsamples of a 5 cm3 wood piece of a single tree-ring from a lowland white fir were used. The samples were milled with different setups: (i) two and three stainless-steel balls, (ii) 3, 5 and 8 min milling time, and (iii) discontinuous and continuous milling. The δ13C values were measured using an elemental analyser connected to an IsoP…
Exposure to toxic agents alters organic elemental composition in human fingernails.
Abstract Background and objective: The human fingernail plate is highly keratinized. The keratin structure is held together by disulfide bonds. The organic elements sulfur and nitrogen occur almost exclusively in amino acids of the nail plate. This study analyzed whether occupational exposure to harmful chemical agents alters the organic elemental composition in fingernails. Subjects and methods: Participants were 71 occupationally exposed workers (49 hairdressers, 22 painters) and 49 unexposed controls. Aspects of exposure were assessed by questionnaire. Nail clippings of index and little fingers were analyzed for sulfur (S), nitrogen (N), carbon (C), and hydrogen (H) contents, using an au…
Comparison of δ(13)C and δ(18)O from cellulose, whole wood, and resin-free whole wood from an old high elevation Pinus uncinata in the Spanish central Pyrenees.
δ(13)C and δ(18)O values from sapwood of a single Pinus uncinata tree, from a high elevation site in the Spanish Pyrenees, were determined to evaluate the differences between whole wood and resin-free whole wood. This issue is addressed for the first time with P. uncinata over a 38-year long period. Results are also compared with published isotope values of α-cellulose samples from the same tree. The differences in δ(13)C and δ(18)O between whole wood and resin-free whole wood vary within the analytical uncertainty of 0.3 and 0.5 ‰, respectively, indicating that resin extraction is not necessary for sapwood of P. uncinata. Mean differences between cellulose and whole wood are 0.9 ‰ (δ(13)C)…
The ivory workshop of Valencina de la Concepción (Seville, Spain) and the identification of ivory from Asian elephant on the Iberian Peninsula in the first half of the 3rd millennium BC
During excavations in the huge ditched enclosure of Valencina de la Concepcion (Seville, Spain), the main centre from the first hierarchical framework-settlement in the Guadalquivir Valley, a pit with remains of a context for producing ivory artefacts, dating from the first half of the 3rd millennium BC, was discovered in the large metallurgical nucleate workshops. Scientific (Optical Microscopy, FIRT and Raman Spectroscopy, C/N Isotope Ratio Mass Spectrometry) analyses revealed that the ivory belonged to Asian elephants and the archaeological study, which was made in a specialized workshop context. In this paper we present the archaeological context, the study of the ivory artefacts and th…
Mikrostickstoffbestimmung durch Verbrennung in einer begrenzten hochprozentigen Sauerstoffatmosph�re
Eine Methode zur Mikrostickstoffbestimmung wird beschrieben, die es erlaubt, mit einer dosierten Menge an Sauerstoff unmittelbar an der Verbrennungsstelle eine hochprozentige Sauerstoffatmosphare zu schaffen. Es gelingt mit dieser Methode, auch in schwer verbrennbaren Substanzen den Stickstoffgehalt bei einer Analysendauer von ca. 6 min und bei geringer Belastung der Rohrfullung zu bestimmen. Bei einer Gesamtzahl von 15 Analysen betrug der Fehler der Einzelmessung 0,17%.
Ringversuch „Massenspektrometrische Präzisionsmassenbestimmung“
Ein Ringversuch ergab, das massenspektrometrische Prazisionsmassenbestimmung mit kommerziellen Geraten mit einer Genauigkeit ausgefuhrt werden konnen, die bezuglich der Berechnung der elementaren Zusammensetzung von Substanzen im allgemeinen hinreichend ist.
La utilización de marfil de cachalote en el Calcolítico de Portugal
Scientific analysis were undertaken within a research project concerning ivory objects from the Chalcolithic to Early Bronze Age of the Iberian Peninsula. In several of the analyses of objects from Portuguese Estremadura, especially V-perforated buttons, we could detect for the first time the presence of sperm whale ivory. This highlights the advantage and necessity of scientific analysis of ivory. It also clearly demonstrates that not all ivory used was ivory from African or Asian elephants, but we also did find ivory from the extinct Elephas antiquus, the hippopotamus and in this case sperm-whale. Thus, already in the Chalcolithic the raw material provenience was highly diverse, which in …