Preservation of DNA in ancient Egyptian mummies

The presence of DNA has been demonstrated in the cell nuclei of an ancient Egyptian mummy fragment. When extracted, this DNA proved to be degraded to a considerable extent and chemically modified. However, the preservation of nucleic acids in this specimen suggests that applying recombinant DNA techniques to the study of ancient mummified tissues might prove to be a fruitful future area of research.     

明墓出土历书的揭取与复原

明墓出土的历书,粘连固结成块,脆硬易于折断。通过实验分析研究,探明其主要原因可能是木质素选择性地吸附的钙铁离子与蛋白质的分解物形成复杂物质,沉积在纸上,渗入书内所致。故揭取该历书的关键是去除钙离子,EDTA二钢,碱性过氧化氢、气相二氧化硅等的分步处理,使脆硬的纸张软化,再逐页分离揭取,然后再去除色素沉淀物,终于恢复了书的原貌。     

X-ray fluorescence analysis of late Roman and Sassanian silver plate

About 200 analyses have been made on late Roman and Sassanian silver objects using energy-dispersive X-ray fluorescence. This has shown that the main feature of the composition of the silver throughout the period and across the geographical area studied was towards high fineness (average silver percentage about 95%). Compositional differences are found between Roman and Sassanian silversmiths' products for the elements copper and lead. Much of the material analysed came from hoards, and using a statistical technique on the analytical data (Discriminant Analysis) broad compositional differences between hoards were found to emerge. The use of different compositions of silver for different joined parts of a single object are discussed.     

Determination of the Fineness of Medieval Coins—Evaluation of Methods in a Case Study of a Medieval Pfennig

The original fineness of coins is very important information that can help us to understand the commercial situation in a wide historical context. This paper deals with a comparison of analytical methods suitable for the evaluation of the actual and original fineness of coins based on a detailed case study of a medieval coin sample. Both non‐destructive (i.e., scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, X‐ray fluorescence, atomic force microscopy and hydrostatic weighing) and destructive (i.e., inductively coupled plasma – mass spectrometry and the Volhard titration method) techniques were used. The original fineness can be also deduced from knowledge of the internal structure of the coin (limited miscibility of copper and silver). A new analytical method based on a combination of a micrograph of the metallographic cross‐section with consequent image analysis was developed for determination of the original fineness. The proposed approach is relatively simple and provides reliable values. Sample heterogeneity and its impact on the determination of fineness are also discussed.     

Studying the process of enamel powder preparation for émail champlevé by colour measurements and μ‐X‐ray mappings

Colour measurements and non‐destructive μ‐X‐ray mappings have been used for the first time in a comprehensive study of medieval émail champlevé works from different production areas in France and Germany. This approach has given a new insight into the enamel powder preparation process of the glass material used for enamelling. Colour measurements demonstrated that all production centres used glass of very similar hues, but with large differences in colour saturation. The μ‐X‐ray mapping results of blue enamels are described by a semi‐qualitative approach. Significant variations in oxide contents of lead, cobalt, manganese and antimony oxides were found. The variations suggest that more than one glass material was used to prepare the powder for enamelling. The variations in antimony and cobalt show that glass had different degrees of opacity and colour depth. The manganese and lead contents, which do not correlate with the cobalt or antimony contents, indicate that probably glass of different base compositions was used to prepare the enamel powder for one champlevé field.     

The application of structured‐light illumination microscopy to hydrocarbon‐bearing fluid inclusions

Structured‐light illumination (SLI)‐based microscopy offers geologists a new perspective for screening of hydrocarbon‐bearing (HCFI) and small aqueous fluid inclusion (AFI) assemblages. This optical‐sectioning technique provides rapid, confocal‐like imaging, using relatively simple and inexpensive instrumentation. The 3D fluorescent images of HCFI planes and large single HCFIs permit the visualization of the relationships between HCFI assemblages, examination of HCFI morphology, and volume estimates of the fluorescent components within HCFIs. By the use of normal white light illumination, SLI image capture, and varying acquisition time it is also possible to image AFI because of the random movements of vapour bubbles within the inclusions. This allows the near‐simultaneous visualization of hydrocarbon and AFI which is of significant importance for the study of sedimentary basins and petroleum reservoirs. SLI is a unique and accessible 3D petrographic tool, with practical advantages over conventional epifluorescence and confocal laser scanning microscopy.     

Computer programmes for the correction of matrix effects in the XRF analysis of glass,ceramics and related silicate systems

The quantitative analysis of glass, ceramics and related silicate systems by means of energy dispersive X-ray fluorescence spectrometry is considered and problems arising from the selective absorption of X-rays in multi-element specimens are discussed. A computer programme written in FORTRAN and based upon a “semi-fundamental parameters” approach to the correction of matrix effects in glass and chemically similar materials is fully described. Model data are provided to enable the programme to be run and tested. An “empirical coefficients” computer programme for the quantitative analysis of silicate systems is outlined and the limitations of this type of programme are pointed out. The importance of adequate sample preparation prior to X-ray spectrometric analysis is stressed.     

Assessing the applicability of portable X-ray fluorescence spectrometry for obsidian provenance research in the Maya lowlands

Recent innovations in portable energy-dispersive X-ray fluorescence (PXRF) spectrometry have increased its utility for the geochemical characterization of obsidian artifacts for archaeological provenance research. However, concerns over the utility of PXRF instrumental analyses have been raised, focused on the validity and reliability of the geochemical data produced. Here we adopt the framework of Richard Hughes (On Reliability, Validity, and Scale in Obsidian Sourcing Research, 1998), whereby reliability addresses instrument stability and issues of measurement while validity pertains to an instrument’s ability to discern geochemical source provenance. This is done in order to test the utility of PXRF instruments for archaeological provenance research. k-Means cluster analysis was used to test the accuracy of PXRF through statistical comparison of data acquired via laboratory and portable energy-dispersive XRF instruments. Multivariate analysis was employed to demonstrate obsidian source representation at two Classic Maya archaeological sites in southern Belize – Uxbenká and Ek Xux – and to test the validity of data obtained from a PXRF instrument in answering archaeological research questions pertaining to regional interactions between lowland Maya polities. Results suggest that portable XRF instruments produce internally consistent results. However, data acquired from a PXRF instrument are not statistically equivalent to other XRF instruments. This is to say that while PXRF is not a reliable technique, it is valid for questions pertaining to geochemical source representation.     

Application of fluorescence lifetime measurements on single petroleum-bearing fluid inclusions to demonstrate multicharge history in petroleum reservoirs

Petroleum-bearing fluid inclusions emit fluorescent light when excited with UV or visible light. The fluorescence decay time of the emission is dependent upon the wavelengths of the excitation and emission light, and the chemical composition of the petroleum oil. In general heavy oils have short lifetimes, whereas the emission from light oils is much longer lived. One can thus use plots of the fluorescence lifetime versus emission wavelength ( τ – λ plots), to show even subtle changes in the chemical composition of the entrapped oil. As a consequence, these τ – λ plots can be used for fluid inclusion research to discriminate different oil populations in situ . In particular, it is demonstrated that τ – λ plots discriminate two sets of inclusion oils in each of four North Atlantic basins [Jeanne d'Arc Basin (Newfoundland), Porcupine Basin (Ireland), Clair field West of Shetland (UK) and Kangerlussuaq Basin (East Greenland)] where multistage oil charge is inferred from other geological evidence.     

Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence

X-ray fluorescence analysis of obsidian artifacts from sites located in Chaco Canyon and from three Chaco-era communities in New Mexico permits determination of their geological origin. These source data are used to describe patterning in obsidian procurement in sites located in Chaco Canyon dating from A.D. 500–1150, and in a three non-Canyon communities occupied during the period of Chaco Canyon's regional prominence (ca. A.D. 875–1150). These data demonstrate that the most proximate sources generally dominate the sourced obsidian assemblages from sites of all periods, but also suggest differences in procurement patterning both over time and across space. Within Chaco Canyon, there is a notable shift from Mount Taylor obsidian to use of Jemez Mountains sources over time. These data also suggest that earlier analyses of obsidian from sites in Chaco Canyon misidentified some obsidian artifact sources; these new data indicate the central areas of disagreement and provide a revision of procurement patterning. In the Chaco-era communities located outside Chaco Canyon, procurement patterning diverges. The Blue J community shows an increase in use of the nearby Mount Taylor source over time. Two communities located toward the southern extent of the Chaco great house distribution reveal a markedly distinct procurement pattern, obtaining nearly all of their obsidian from southern sources largely unrepresented at Chaco Canyon. Combined, these data provide new insights into raw material procurement and artifact production at sites in Chaco Canyon, and in communities occupied during the Chaco Phenomenon, the period of the Canyon's greatest regional influence.