Investigating the impact of cleaning treatments on polystyrene using SEM, AFM and ToF–SIMS

Concerns about the stability of plastic artefacts are commonly expressed when discussing the conservation of modern materials. One of the factors affecting the degradation of plastics is the presence of soil, degradation products and other contaminants on the surface. Cleaning treatments for plastic artefacts may therefore increase their stability as well as improving their visual appearance. While past studies have shown that dry, aqueous and solvent cleaning can visibly damage a plastic surface, the chemical and physical changes occurring to the surface at the micro-scale have been largely unexplored. In this work time-of-flight secondary ion mass spectrometry (ToF–SIMS) has been used in conjunction with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to examine the effect of cleaning treatments on the surface of sheet polystyrene. Chemometric analysis of the ToF–SIMS data reveals the presence of surfactant residues and contamination from cleaning agents while physical damage in the form of scratching has been characterised using AFM and SEM. It is anticipated such work will assist in informing future conservation treatments for plastics

Altered Brain Structure in Infants with Turner Syndrome

Turner syndrome (TS) is a genetic disorder affecting approximately 1:2000 live-born females. It results from partial or complete X monosomy and is associated with a range of clinical issues including a unique cognitive profile and increased risk for certain behavioral problems. Structural neuroimaging studies in adolescents, adults, and older children with TS have revealed altered neuroanatomy but are unable to identify when in development differences arise. In addition, older children and adults have often been exposed to years of growth hormone and/or exogenous estrogen therapy with potential implications for neurodevelopment. The study presented here is the first to test whether brain structure is altered in infants with TS. Twenty-six infants with TS received high-resolution structural MRI scans of the brain at 1 year of age and were compared to 47 typically developing female and 39 typically developing male infants. Results indicate that the typical neuroanatomical profile seen in older individuals with TS, characterized by decreased gray matter volumes in premotor, somatosensory, and parietal-occipital cortex, is already present at 1 year of age, suggesting a stable phenotype with origins in the prenatal or early postnatal period

Homogeneous Subgroups of Young Children with Autism Improve Phenotypic Characterization in the Study to Explore Early Development

The objective of this study was to identify homogenous classes of young children with autism spectrum disorder (ASD) to improve phenotypic characterization. Children were enrolled in the Study to Explore Early Development between 2 and 5 years of age. 707 children were classified with ASD after a comprehensive evaluation with strict diagnostic algorithms. Four classes of children with ASD were identified from latent class analysis: mild language delay with cognitive rigidity, mild language and motor delay with dysregulation, general developmental delay, and significant developmental delay with repetitive motor behaviors. We conclude that a four-class phenotypic model of children with ASD best describes our data and improves phenotypic characterization of young children with ASD. Implications for screening, diagnosis, and research are discussed

Applying refinement to the use of mice and rats in rheumatoid arthritis research

Rheumatoid arthritis (RA) is a painful, chronic disorder and there is currently an unmet need for effective therapies that will benefit a wide range of patients. The research and development process for therapies and treatments currently involves in vivo studies, which have the potential to cause discomfort, pain or distress. This Working Group report focuses on identifying causes of suffering within commonly used mouse and rat ‘models’ of RA, describing practical refinements to help reduce suffering and improve welfare without compromising the scientific objectives. The report also discusses other, relevant topics including identifying and minimising sources of variation within in vivo RA studies, the potential to provide pain relief including analgesia, welfare assessment, humane endpoints, reporting standards and the potential to replace animals in RA research

Characterisation of a divergent progenitor cell sub-populations in human osteoarthritic cartilage: the role of telomere erosion and replicative senescence

In recent years it has become increasingly clear that articular cartilage harbours a viable pool ofprogenitor cells and interest has focussed on their role during development and disease. Analysis ofprogenitor numbers using fluorescence-activated sorting techniques has resulted in wide-rangingestimates, which may be the result of context-dependent expression of cell surface markers. Wehave used a colony-forming assay to reliably determine chondroprogenitor numbers in normal andosteoarthritic cartilage where we observed a 2-fold increase in diseased tissue (P < 0.0001). Intriguingly,cell kinetic analysis of clonal isolates derived from single and multiple donors of osteoarthritic cartilagerevealed the presence of a divergent progenitor subpopulation characterised by an early senescentphenotype. Divergent sub-populations displayed increased senescence-associated β–galactosidaseactivity, lower average telomere lengths but retained the capacity to undergo multi-lineagedifferentiation. Osteoarthritis is an age-related disease and cellular senescence is predicted to be asignificant component of the pathological process. This study shows that although early senescenceis an inherent property of a subset of activated progenitors, there is also a pool of progenitors withextended viability and regenerative potential residing within osteoarthritic cartilage

Optimization of Enzymatic Biochemical Logic for Noise Reduction and Scalability: How Many Biocomputing Gates Can Be Interconnected in a Circuit?

We report an experimental evaluation of the "input-output surface" for a biochemical AND gate. The obtained data are modeled within the rate-equation approach, with the aim to map out the gate function and cast it in the language of logic variables appropriate for analysis of Boolean logic for scalability. In order to minimize "analog" noise, we consider a theoretical approach for determining an optimal set for the process parameters to minimize "analog" noise amplification for gate concatenation. We establish that under optimized conditions, presently studied biochemical gates can be concatenated for up to order 10 processing steps. Beyond that, new paradigms for avoiding noise build-up will have to be developed. We offer a general discussion of the ideas and possible future challenges for both experimental and theoretical research for advancing scalable biochemical computing