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Plasticiser loss is a topic frequently mentioned in discussions on the degradation of plastic artefacts in museum collections, particularly for plasticised poly (vinyl chloride) and cellulose acetate. Plasticisers may migrate to the plastic’s surface and remain as a deposit, or volatilise into the surrounding environment, both presenting an aesthetic issue and impacting the future stability of the plastic. This paper draws on the work of conservation science, materials degradation, and indoor air quality/emissions studies, to review our current understanding of plasticiser loss. The influence of the material’s intrinsic properties, and environmental factors on migration rates are discussed and related to preventive conservation practices. The methods by which plasticiser migration is studied, including characterisation, are also reviewed, with a particular focus on minimally invasive and non-destructive methods suitable for heritage science research.

Silver gelatine photographs were the most dominant photographic process of the twentieth century from the 1880s until the 1960s. They are prone to yellowing, mirroring and fading which is largely attributed to the effects of pollutants, relative humidity and residual processing chemicals. Experts in the conservation of photographs claim they can determine the causes of deterioration with the naked eye: the effects of humidity result in a more yellowed appearance, whilst the presence of residual chemicals results in a redder appearance. This work aims to investigate if the same deterioration processes can be diagnosed in photographic prints with a spectrophotometer by addressing two questions: (1) In new and artificially aged silver gelatine photographs is it possible to distinguish between discolouration caused by silver migration and that caused by the presence of residual sulfur? (2) What are the complexities of applying these findings to historic photographs? A set of test photographs, some well processed and some insufficiently washed was developed and artificially aged. These were compared to a small collection of historical photographs of different ages, paper types and image colours. Samples were assessed using visual observation, residual silver and hypo spot tests, colour measurements including L*a*b* and reflectance spectra, Fourier transform infra-red (FTIR) spectroscopy and transmission electron microscopy (TEM). After artificial ageing the well processed test photographs were more yellowed, TEM indicated that this was due to colloidal silver formation. The insufficiently washed test photographs were more red but also darker, TEM showed these samples to have more homogeneous silver filaments, thought to be due to silver sulfide formation. The results for the historical photographs were similar but more subtle. A larger sample set is needed to investigate this more extensively. Further investigation on historical samples, with colour measurements and residual silver and fixer spot tests will take place.

Near infrared spectroscopy (NIR) can be a useful diagnostic tool in the assessment of quality in textile, agricultural and various other industries. In cultural heritage applications, NIR as a non-invasive assessment tool is advantageous for understanding the composition or degradation of fragile historic objects that cannot be sampled. The direct interpretation of measured NIR spectra is complicated by overlapping bands produced from overtone and combination bands of chemical bonds. However, in combination with multivariate partial least squares (PLS) models and principal component analysis, the physicochemical properties of historic materials can potentially be identified by calibrating against a measured component. In this research, wool fibres from a sacrificial collection of historic tapestry fragments housed at Hampton Court Palace were analysed. The cystine oxidation products of historic wools which can be related to the embrittlement of fibres and ultimately fibre loss, were recorded using Fourier transform infrared (FTIR) spectroscopy. A PLS predictive model was then developed using previously measured NIR spectra for the same historic tapestry fragments to predict the ratios of the cystine oxidation species in historic wools measured in this research. The prediction of a validation set of historic tapestry fragments with known oxidation product ratios was found to be accurate to root mean squared errors of prediction (RMSEP) of 0.11 for cysteic acid/cystine dioxide, 0.03 for an oxidation ratio of cysteic acid/cystine monoxide and 0.06 for cystine dioxide/cystine monoxide. The model was applied successfully to an independent set of historic tapestry fragments with unknown oxidation ratios with an M-distance pass limit of 3. The models were also applied to NIR measurements of historic tapestries on open display with limited success. Alternative methods to investigate and account for errors in this research are proposed. The potential for NIR to be used by conservators as a non-invasive tool for the assessment of textiles, complementing current condition audit practices in use at heritage institutions is also discussed.

Cellulose‐derived materials, like paper and cellulose acetate, are known to be vulnerable to degradation within museum collections. Studies have been conducted and degradation markers have been identified on these materials. However, the degradation of man‐made cellulose‐derived fibers in collections is not well understood. This study aims to provide insights into historical cellulose acetate and regenerated cellulose textiles to quantify their physical and chemical changes during degradation using accelerated ageing experiments. Potential physical and chemical markers for degradation are identified, including changes in surface morphology, mass loss, discoloration and changes in spectral bands. These markers can be used to improve understanding of the degradation mechanisms of historical cellulose acetate and regenerated cellulose textiles and guide the development of conservation strategies. These findings have important implications for understanding the stability of man‐made cellulosic fibers in museum collections. Cellulose‐derived materials, such as paper and cellulose acetate, degrade in museum collections. The degradation of man‐made cellulose fibers remains poorly understood. This study examines historical cellulose acetate and regenerated cellulose textiles using accelerated ageing. Identified markers, for instance surface changes, mass loss, discoloration, and spectral shifts, provide enhanced understanding of degradation behavior and inform conservation and preservation strategies.

There is an acknowledged need for improved conservation of plastic and rubber objects within collections, including improved methods of condition assessment, material identification, and better understanding of material degradation. This reflects the inherent instability and wide-ranging formulations of many such objects and also the relative lack of knowledge in this field. Analysis of volatile organic compounds (VOCs) is a useful method for understanding the chemical processes involved in polymer degradation and for the identification of materials. Conservators and curators have used odor analysis to identify historical plastics for many years, and techniques ranging from acid detection strips to laboratory-based techniques such as solid-phase microextraction-gas chromatography-mass spectrometry have been used to characterize plastic and rubber materials and to understand their degradation. VOC analysis also has potential as a technique for bulk material identification, as a complementary tool to spectroscopic analysis of the surface. A significant advantage of VOC analysis is its potential to be non-invasive, avoiding destructive sampling or even contact with an object. However, there is a greater potential for VOC analysis to be of benefit within conservation than is currently being exploited and significant scope for future research. In fields such as construction or waste management, there is also significant research into analysis of VOC emissions from plastic and rubber materials. The goal of this paper is to systematically review research from a range of fields including conservation, polymer degradation, and plastics recycling and it includes the use of VOC analysis to understand the causes of damage to plastic and rubber objects, to provide evidence of degradation and to monitor degradation progress, and to identify materials and distinguish between different formulations. Summaries of relevant studies are given, and volatile markers of object damage and polymer degradation and key volatile identifiers of a particular material are highlighted.

This multicenter, prospective, randomized controlled trial (NCT03285152) evaluates the primary endpoint of feasibility of a very-low carbohydrate diet (VLCD) in 19 women with obesity/overweight and endometrial cancer, who are randomized 2:1 to either a VLCD or a standard diet for 21-28 days. Fifteen participants complete the study, with 91 ± 4% of VLCD meals consumed, 5.5 ± 0.8% weight lost, and no grade 3/4 adverse events. Secondary endpoints include assessments of tumor biology and circulating metabolic biomarkers. Fasting glucose and insulin fall 22 ± 5.9% and 60 ± 3.8%, while total cholesterol and low-density lipoprotein (LDL) rise 6 ± 2.7% and 17.8 ± 8.9%. In a pre-specified exploratory outcome, RNA-Seq shows enrichment of CD8 + T-cells (q < 0.034; NES > 1.75), confirmed by immunohistochemistry (IHC) showing CD8 + T-cells infiltration of the tumor margins (q = 0.034; NES = 1.75). We conclude that VLCD is feasible and well-tolerated.

Systematic condition and analytical surveys were carried out on Zoe Leonard’s (b. 1961) Mouth Open, Teeth Showing 2000, an installation artwork in Tate’s collection consisting of 162 children’s dolls. The dolls were manufactured at various points within the 20th century and encompass several potentially problematic synthetic polymers found in modern and contemporary museum collections. To explore the doll materials and conservation condition, a multi-analytical approach was used to identify key synthetic polymer types and additives present, including portable and bench analytical techniques. Challenging degradation phenomena associated with different types of doll have been discussed and related to their material composition, which has helped our understanding of the conservation challenges inherent to this contemporary artwork.

Systematic condition and analytical surveys were carried out on Zoe Leonard’s (b. 1961) Mouth Open, Teeth Showing 2000, an installation artwork in Tate’s collection consisting of 162 children’s dolls. The dolls were manufactured at various points within the 20th century and encompass several potentially problematic synthetic polymers found in modern and contemporary museum collections. To explore the doll materials and conservation condition, a multi-analytical approach was used to identify key synthetic polymer types and additives present, including portable and bench analytical techniques. Challenging degradation phenomena associated with different types of doll have been discussed and related to their material composition, which has helped our understanding of the conservation challenges inherent to this contemporary artwork.