唐代鎏金铜天王像的保护与研究

依据现代科学检测方法,对唐代鎏金铜天王像不同部位的锈蚀产物进行了系统分析。运用软硬酸碱之间相互反应规律的理论,制定了以EDTA为主的配位体参加除锈反应的方案。综合多年的工作经验,找出络合反应中的最佳反应条件,从理论和实践中总结出较为可行的鎏金器物保护方法。     

High performance liquid chromatography (HPLC) in the investigation of gout in palaeopathology

Gout is a disease caused by the abnormal accumulation of uric acid in the body, which can result in sodium urate crystals forming tophi at joints, with associated erosion of bone and cartilage. Only two examples of tophi have been reported from archaeological individuals, and the diagnosis of gout based on dry bone manifestations can be difficult. This paper presents preliminary results of a new technique to aid the diagnosis of gout in palaeopathology, namely high performance liquid chromatography (HPLC). Five archaeological skeletons with suspected gout (diagnosed using visual and radiological analysis) and three controls were analysed. Two of the gouty individuals had a white powder in their erosive lesions. HPLC showed the presence of uric acid in bone in four of the five individuals with evidence of gouty arthritis and was negative for uric acid in bone from the three controls. The white powder was also positive for uric acid. With reliance on the presence of articular erosions, cases of gout will be missed in archaeological human bone. HPLC measurement of uric acid could prove useful in the differential diagnosis of erosive arthropathy in archaeology. It may also be useful in identifying individuals with an increased body pool of uric acid, linked to conditions included in the term ‘metabolic syndrome’. As a result, HPLC uric acid measurement also has the potential to provide additional information on health and lifestyle in past communities. Copyright © 2008 John Wiley & Sons, Ltd.     

Modern and fossil charcoal: aspects of structure and diagenesis

The structures and compositions of modern and fossil charcoal samples were compared in order to evaluate charcoal degradation processes in archaeological sites. Modern charcoal samples produced in campfires contain two major phases: graphite-like microcrystallites and a non-organized phase. These phases create a mosaic-like structure with differing relative proportions depending on the taxonomic source of the wood used. Fossil charcoal samples (Tel Dor, Israel: 3000 years BP and Kebara Cave, Israel: 40,000 years BP) also contained the graphite-like microcrystallites and the non-organized phases, but were clearly altered compared to modern charcoal. The graphite-like phase of the fossil charcoal has much higher electrical resistivity, and its ESR properties show that it has markedly altered surface electronic states. Infrared spectra show the presence of additional carboxylate groups. Oxidation has therefore altered the structure. This appears to be a “self-humification” process that affects the graphitic component, and probably the non-organized phase as well.     

Organic–inorganic rock–fluid interactions in stylolitic micro‐environments of carbonate rocks: a FIB‐TEM study combined with a hydrogeochemical modelling approach

Stylolites and the interfaces to the host limestone have been investigated by means of a multidisciplinary analytical approach (thin section microscopy, FIB‐TEM, organic geochemistry and petrography). Carbonate dissolution assuming different boundary conditions was simulated by applying a generic hydrogeochemical modelling approach. It is the conceptual approach to characterize and quantify traceable organic–inorganic interactions in stylolites dependent on organic matter type and its thermal maturity, and to follow stylolite formation in carbonates as result of organic matter reactivity rather than pressure solution as a main control. The investigated stylolite samples are of Upper Permian (Lopingian, Zechstein), Middle Triassic (Muschelkalk) and Late Cretaceous (Maastrichtian) age and always contain marine organic matter. The thermal maturity of the organic matter ranges from the pre‐oil generation zone (0.4–0.5% R_r) to the stage of dry gas generation (>1.3% R_r). The results of the generic hydrogeochemical modelling indicate a sharp increase of calcite dissolution and the beginning of stylolite formation at approximately 40°C, which is equivalent to a depth of less than 800 m under hydrostatic conditions considering a geothermal gradient of 30°C and a surface mean temperature of 20°C. This temperature corresponds to the pre‐oil window when kerogens release an aqueous fluid enriched in carbon dioxide and organic acids. This aqueous fluid may change the existing pore water pH or alkalinity and causes dissolution of carbonate, feldspar and quartz, and clay mineral precipitation along the stylolite. Dissolution of limestone and dolostone leads to reprecipitation of calcite or dolomite opposite of the dissolution side, which indicates only localized mass redistribution. All these integrated hydrogeochemical processes are coupled to the generation of water during organic matter maturation. In all of the calculated hydrogeochemical scenarios, H₂O is a reaction product and its formation supports the suggested hypothesis.     

Examination of prehistoric artifacts via fatty acid methyl ester (FAME) techniques using modern environmental stewardship

Elucidating the specific use and purpose of archaeological specimens such as stone axes and grinding stones can improve the understanding of an area's ecosystem and civilization. Chemical analysis of residues preserved on these tools may provide key information in identifying how the tool was implemented. The arid US Great Basin provides an ideal environment for the preservation of fatty acid residues.     

德国多孔隙石质古迹化学增强保护新材料和新施工工艺

介绍了20世纪90年代德国石质古迹化学增强保护的新材料和新的施工工艺,提出呈皮壳状风化石雕保护的建议。     

Lipoic acid formulations for the removal of arsenic and mercury from museum artifact materials

Museums currently face a tremendous task of identification, mitigation, and remediation of pesticides from artifacts in order to protect museum workers and the general public. Additionally artifacts are being repatriated by Native American tribes for use in cultural ceremonies which may subject the practitioner to health risks. Arsenic and mercury salts are among the most persistent poisons used and so a critical challenge is removing these hazardous metals without damaging the material composition or decorations of the objects. At this time, there are no feasible procedures that can meet both of these objectives. Reported here is the development of a procedure involving concentrated aqueous reduced lipoic acid solutions for the removal of arsenic and mercury pesticides from substrate materials commonly encountered in museums.     

Alkali extraction of archaeological and geological charcoal: evidence for diagenetic degradation and formation of humic acids

Charcoal forms a crucial source of archaeological and palaeoenvironmental data, providing a record of cultural activities, past climatic conditions and a means of chronological control via radiocarbon (¹⁴C) dating. Key to this is the perceived resistance of charcoal to post-depositional alteration, however recent research has highlighted the possibility for alteration and degradation of charcoal in the environment. An important aspect of such diagenesis is the potential for addition of exogenous “humic acids’ (HAs), to affect the accuracy of archaeological and palaeoenvironmental reconstructions based upon chemical analyses of HA-containing charcoal. However the release of significant quantities of HA from apparently pristine charcoals raises the question whether some HA could be derived via diagenetic alteration of charcoal itself. Here we address this question through comparison of freshly produced charcoal with samples from archaeological and geological sites exposed to environmental conditions for millennia using elemental (C/H/O) and isotopic (δ¹³C) measurements, Fourier Transform Infrared Spectroscopy (FTIR) and proton Liquid-State Nuclear Magnetic Resonance (¹H NMR). The results of analyses show that the presence of highly carboxylated and aromatic alkali-extractable HA in charcoal from depositional environments can often be attributable to the effects of post-depositional processes, and that these substances can represent the products of post-depositional diagenetic alteration in charcoal.     

Archaeological collagen: Why worry about collagen diagenesis?

DNA appears to decay by random chain scission resulting in a predictable range of fragment lengths. Collagen decay has also been modelled in this same way, although it has become increasingly evident that collagen decay does not follow this same pattern. Radiocarbon and stable isotope analysis now use ultra-filtration to isolate large fragments (>30% of original polymer length) even in Pleistocene bone. How then does collagen decay? This study contrasts experimentally degraded samples with collagen extracted from forensic, archaeological and fossil bone. In experimentally degraded bone, values for amino acid and elemental (C:N) composition, bulk δ ¹³C, δ ¹⁵N, and aspartic acid racemisation (AAR) changed very little until 99% of the collagen was lost, suggesting that the collagen triple helix and polypeptide chains remained remarkably intact. This suggestion was demonstrated directly by examining the integrity of individual polypeptide chains using cyanogen bromide (CNBr) cleavage followed by SDS-PAGE electrophoresis. In ancient samples, AAR values remain remarkably stable and the pattern of CNBr-cleavage was only replaced with a smear of smaller polypeptides in the oldest (Pleistocene) bones investigated. Smearing may reflect both modification of the methionine resides (the sites of CNBr-cleavage) and/or partial hydrolysis of the collagen molecule. The findings reveal why it is not usually necessary to worry about collagen diagenesis; it is mostly intact. However, evidence of partial deterioration of the oldest bone samples suggests that alternative purification strategies may increase yields in some samples.     

New investigations into the Uluburun resin cargo

Resin found within Canaanite amphorae from the Late Bronze Age shipwreck discovered off the coast of southwest Turkey at Uluburun has previously been identified as Pistacia sp. Although evidence from Egypt suggests that this resin was in high demand and typically transported in such amphorae, it has also been proposed that the amphorae contained wine, with the resin used to seal the interior surfaces and to flavour and/or preserve the wine. To attempt to resolve this question, we have analysed five samples of pistacia resin found in amphorae from the shipwreck using a range of analytical techniques which have used in the past for the analysis of wine residues: spot tests, FT-IR, and HPLC-MS-MS. As well as the archaeological samples, we have analysed modern samples of pistacia resin, leaves and fruit to determine the effectiveness of each technique and to exclude the possibility of false positive results. In addition to the analyses for wine we also detail analysis (GC-MS) of the terpenoids for the purpose of further molecular characterisation of the resin. Bulk stable isotope analysis was used in comparison with similar resins to attempt to identify the geographical origin of the resin.