Development of non-destructive methodology using ATR-FTIR with PCA to differentiate between historical Pacific barkcloth

Barkcloths, non-woven textiles originating from the Pacific Islands, form part of many museum collections and date back to the 18th and 19th centuries. The ability to determine different plant species which have been used for producing barkcloth is required by art historians to help understand the origin and use of the cloths and by conservators for whom the species type may have an impact on textile durability, deterioration and hence conservation. However, to date the development of a non-destructive, robust analytical technique has been elusive. This article describes the use of Fourier transform infrared spectroscopy with attenuated total reflection (ATR-FTIR) and principal component analysis (PCA) todifferentiation between historic barkcloths. Three distinct groups of historic cloths were identified using PCA of the FTIR region between 1200 and 1600 cm−1 where molecular vibrations associated with tannins and lignins are dominant. Analysis of contemporary cloths only identified Pipturus albidus cloth as different and highlighted the difficulties around producing a representative textile sample to mimic the historic cloths. While the methodology does not itself identify species, the use of historically well-provenanced samples allows cloths showing similarities to group together and is a significant aid to identification

'Like-With-Like’: A Comparison of Natural and Synthetic Stitching Threads used in Textile Conservation

This paper reports research undertaken to investigate thread types used in textile conservation by quantitatively evaluating tensile strength and damage to conserved samples. A literature review and questionnaire sent to textile conservators were used to establish the most commonly used threads for laid-thread couching treatments and the rationale behind thread choice. Most common threads found were two-ply hair silk and polyester Tetex as well as other fine polyester, silk and cotton varieties. Three natural fibre plain-weave artefact samples conserved by laid-thread couching with five different thread types (lace cotton, hair silk, organsin, Skala and Tetex) were subjected to either tensile strength testing or a fixed-load experiment for two weeks. The tensile strength tests determined that the conservation treatment provided effective support and different thread types did not give statistically different results. The fixed-load experiment determined that longer time periods created more damage, even with lighter loads

Mechanical properties of wool and cotton yarns used in twenty-first century tapestry: preparing for the future by understanding the present

The conservation of historic tapestries is a complex and highly skilled task. Tapestries now being woven will need conservation in years to come. Can we, by understanding the properties of these contemporary works, assist the conservators of the future? The recreation of the Hunt of the Unicorn tapestries being undertaken by the West Dean Tapestry Studio offers a unique opportunity to access the materials being used and to create a body of data on their initial properties. This study uses tensile testing of the warp and weft materials to determine their maximum load at break, extension at maximum load, and specific stress (tenacity). Wool weft yarns from two different sources and of two thicknesses were examined. These wools were dyed ‘in house’ and the effect of the different dyes used was also assessed. These parameters all showed some significant (P < 0.05) differences. Cotton warp yarns of differing thickness and a gold thread were also tested. The comparison of how cotton and wool break demonstrates that when a tapestry is put under sufficient stress the cotton will snap but the wool may only stretch. However, this could often be beyond its recovery range resulting in a failure to return to shape

The use of hydrogels to prevent biofouling on underwater sensors

The biofouling resistant coatings of hydrogel containing the cationic surfactants benzalkonium chloride and Arquad 2C-75 both extended the fouling free period in marine temperate waters. In the case of BAC the coating stayed clean for 10-12 weeks and the Arquad 2C-75 for 12-14 weeks. Due to the longer life of the hydrogel containing the Arquad 2C-75 instrument trials were carried out using this material. An effective method of attaching the coatings to the optical and membrane ports of sensors was developed and allows the coating to be either held in either a screw down or bolted polymer ring. The diffusion coefficient of cationic surfactants in seawater is reduced compared to diffusion coefficients in freshwater. In seawater the diffusion coefficient of benzalkonium chloride was found to be 2.44 x 10-6 cm2 s-1 compared to 7.78 x 10-6 cm2 s-1 in distilled water at 25°C. Careful choice of gas permeable membrane can result in a slightly longer biofouling lifetime, but only by 1-2 weeks. At 6 weeks all gas permeable membranes had significant fouling which affected their gas permeability. The diffusion rates of ammonia gas, a gas commonly measured in the sea, through PTFE gas sensor membranes varied between PTFE manufacturers with flux measurements ranging from 0.05-1131 µg cm-2 h-1. In addition to the hydrogel testing on instruments within this project a variety of external research groups and environmental agencies are currently testing the hydrogels on their instrumental ports

Pacific barkcloth under the microscope - characterisation of condition, decoration and structure

The creation of barkcloth begins with harvesting the inner bark of certain types of trees followed by soaking and beating with grooved beaters, a process which often leaves undulations on the surface of the bark, also known as the beater mark. The cloth can then be decorated using colorants, applied as particulate pigments, dyes or paints. The resulting material is highly ornate with varying surface textures and colours. The usefulness of stereo and standard light microscopy, ranging from around x10 for low and up to x200 for high-magnification microscopy, and macro photography to examine the subtleties of the surface of the cloth is highlighted in this research, with examples of barkcloth from the Hunterian, University of Glasgow, Glasgow and Royal Botanic Gardens, Kew, London collections. Examples of beater marks, particulate dye material, cracking painted surfaces, as well as the presence of two species used to create one cloth are shown, aspects that are not immediately obvious when examining the cloths with the naked eye. To further enhance the analysis from microscopy XRF and FTIR were used when appropriate. Observing the material in this way can increase appreciation for the aesthetic aspects of barkcloth and can further knowledge of the materials used in production. This can inform condition reports, storage requirements, and potential conservation treatments

Solvent vapour use - the unintended consequences in textile conservation

The impact of solvent vapour from two solvents, acetone and industrial denatured alcohol (IDA), commonly used in adhesive reactivation in textile conservation, when applied to artificially soiled silk fabric through either Gore-Tex® or Reemay® membranes for exposure times of either 1 or 3 min, was measured using microscopy and ImageJ to monitor the movement of the solid particulates of the soiling, and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) to monitor the movement of the oily components. Analysis using these techniques successfully showed the movement of large particulates through the textile and a decrease in the presence of oil. Analysis with FTIR-ATR showed that the application of solvent vapour by a poultice method produces more than just a surface change and the vapour can penetrate far enough into the fibres to cause a change in the level of oil through the entire textile. The results showed that the solvents and barrier membranes have characteristic differences which impact on the changes on the soiling. The application of acetone produced a greater change in the movement of oil on the front and back of the samples than the application of IDA, while a comparison between the barrier membranes showed a greater change occurring in the level of oil with the use of Gore-Tex® rather than Reemay®. The time of exposure to solvent vapour made little difference to the changes to the textile soiling. Quantitatively significant results were gathered from analysis of the changes in the oil measured with FTIR-ATR, and qualitative changes in the large particulate soiling, demonstrating the potential usefulness of ImageJ open access software in future historic textile soiling monitoring studies

Rapid detection of Listeria monocytogenes in food using culture enrichment combined with real-time PCR.

A rapid method for the detection of Listeria monocytogenes in foods combining culture enrichment and real-time PCR was compared to the ISO 11290-1 standard method. The culture enrichment component of the rapid method is based on the ISO standard and includes 24h incubation in half-Fraser broth, 4h incubation in Fraser broth followed by DNA extraction and real-time PCR detection of the ssrA gene of L. monocytogenes. An internal amplification control, which is co-amplified with the same primers as the L. monocytogenes DNA, was also included in the assay. The method has a limit of detection of 1-5CFU/25g food sample and can be performed in 2 working days compared to up to 7days for the ISO standard. A variety of food samples from retail outlets and food processing plants (n=175) and controls (n=31) were tested using rapid and conventional methods. The rapid method was 99.44% specific, 96.15% sensitive and 99.03% accurate when compared to the standard method. This method has the potential to be used as an alternative to the standard method for food quality assurance providing rapid detection of L. monocytogenes in food

Prediction-based classification for longitudinal biomarkers

Assessment of circulating CD4 count change over time in HIV-infected subjects on antiretroviral therapy (ART) is a central component of disease monitoring. The increasing number of HIV-infected subjects starting therapy and the limited capacity to support CD4 count testing within resource-limited settings have fueled interest in identifying correlates of CD4 count change such as total lymphocyte count, among others. The application of modeling techniques will be essential to this endeavor due to the typically nonlinear CD4 trajectory over time and the multiple input variables necessary for capturing CD4 variability. We propose a prediction-based classification approach that involves first stage modeling and subsequent classification based on clinically meaningful thresholds. This approach draws on existing analytical methods described in the receiver operating characteristic curve literature while presenting an extension for handling a continuous outcome. Application of this method to an independent test sample results in greater than 98% positive predictive value for CD4 count change. The prediction algorithm is derived based on a cohort of $n=270$ HIV-1 infected individuals from the Royal Free Hospital, London who were followed for up to three years from initiation of ART. A test sample comprised of $n=72$ individuals from Philadelphia and followed for a similar length of time is used for validation. Results suggest that this approach may be a useful tool for prioritizing limited laboratory resources for CD4 testing after subjects start antiretroviral therapy.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS326 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Incontinence-specific quality of life measures used in trials of treatments for female urinary incontinence: a systematic review.

This systematic review examined the use of incontinence-specific QOL measures in clinical trials of female incontinence treatments, and systematically evaluated their quality using a standard checklist. Of 61 trials included in the review, 58 (95.1%) used an incontinence-specific QOL measure. The most commonly used were IIQ (19 papers), I-QoL (12 papers) and UDI (9 papers). Eleven papers (18.0%) used measures which were not referenced or were developed specifically for the study. The eight QOL measures identified had good clinical face validity and measurement properties. We advise researchers to evaluate carefully the needs of their specific study, and select the QOL measure that is most appropriate in terms of validity, utility and relevance, and discourage the development of new measures. Until better evidence is available on the validity and comparability of measures, we recommend that researchers consider using IIQ or I-QOL with or without UDI in trials of incontinence treatments

Therapeutic efficacy of anti-MMP9 antibody in combination with nab-paclitaxel-based chemotherapy in pre-clinical models of pancreatic cancer

Matrix metalloproteinase 9 (MMP9) is involved in the proteolysis of extracellular proteins and plays a critical role in pancreatic ductal adenocarcinoma (PDAC) progression, invasion and metastasis. The therapeutic potential of an anti-MMP9 antibody (αMMP9) was evaluated in combination with nab-paclitaxel (NPT)-based standard cytotoxic therapy in pre-clinical models of PDAC. Tumour progression and survival studies were performed in NOD/SCID mice. The mechanistic evaluation involved RNA-Seq, Luminex, IHC and Immunoblot analyses of tumour samples. Median animal survival compared to controls was significantly increased after 2-week therapy with NPT (59%), Gem (29%) and NPT+Gem (76%). Addition of αMMP9 antibody exhibited further extension in survival: NPT+αMMP9 (76%), Gem+αMMP9 (47%) and NPT+Gem+αMMP9 (94%). Six-week maintenance therapy revealed that median animal survival was significantly increased after NPT+Gem (186%) and further improved by the addition of αMMP9 antibody (218%). Qualitative assessment of mice exhibited that αMMP9 therapy led to a reduction in jaundice, bloody ascites and metastatic burden. Anti-MMP9 antibody increased the levels of tumour-associated IL-28 (1.5-fold) and decreased stromal markers (collagen I, αSMA) and the EMT marker vimentin. Subcutaneous tumours revealed low but detectable levels of MMP9 in all therapy groups but no difference in MMP9 expression. Anti-MMP9 antibody monotherapy resulted in more gene expression changes in the mouse stroma compared to the human tumour compartment. These findings suggest that anti-MMP9 antibody can exert specific stroma-directed effects that could be exploited in combination with currently used cytotoxics to improve clinical PDAC therapy