Sensory Mapping of Lumbar Facet Joint Pain : A feasibility study

Acknowledgements The authors would like to thank Dr Jeremy Weinbren, Consultant Anaesthetist, The Hillingdon Hospitals NHS Foundation Trust for his statistical advice on this paper. Funding The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: K.F. received a John Snow Anaesthesia Intercalated BSc bursary. No funding was obtained for the running costs of the project.Peer reviewedPostprin

Filtration of Nanoclay Clusters During Resin Transfer Molding of Clay Glass Epoxy Disks

Inclusion of nanoclay in various polymer systems is being studied as a viable improvement method for thermo-mechanical properties for more than a decade. It has also been shown that addition of nanoclay into polymers significantly enhances thermal durability of the part. It is possible that the addition of nanoclay to conventional fiber- reinforced composites would provide enhanced mechanical and thermal performance. However, the interaction of nano-scale clay platelets and somewhat larger clay clusters with micro-scale fibers might lead to non-uniform clay content throughout a molded composite part. In this study we investigate the dispersion of nanoclay in resin transfer molded clay/glass/epoxy disks. For this purpose 4 composite disks are fabricated by resin transfer molding. In addition to 14% glass fiber reinforcement, disks contained either 0, 2, 5 or 10wt.% Cloisite® 25A nanoclay. The spatial distribution of nanoclay clusters in the radial axis of the nanocomposite disks are characterized at two length scales. Clusters larger than 1.5µm are characterized by performing image analysis on the SEM micrographs obtained at 50X, whereas smaller nanoclay clusters are identified by wavelength dispersive spectrometry. In addition, to characterize the interaction of nanoclay with the polymer at the molecular level, glass transition temperature of each disk is measured under oscillatory shear. Results obtained from image analysis indicate that as much as 50% of the nanoclay clusters are filtered out in the flow direction by the glass fiber preform. In addition, higher filtration with increasing nanoclay content suggests that clustering is more effective at higher nanoclay loadings. As a result of filtration and possible cluster breakdown, the contribution of small clusters (i.e., Area120µm2) at the outer edges of the disks. Glass transition temperature is observed to increase with increasing nanoclay content, suggesting that the gallery spacing of the nanoclay structures are intercalated by the epoxy resin.Ye

Multiscale Dispersion Characterization and Breakdown of Nanoclay Clusters during Molding

Thermo-mechanical properties of polymers can be significantly altered by the addition of nano-scale particulates such as carbon nanotubes and nanofibers. Among the nano-scale particulates, inclusion of nanoclay is proven to improve thermal and mechanical properties of polymers significantly even at small volume fraction levels. In addition, nanoclay is a viable commercial alternative to conventional fillers owing to its low-cost and accessibility. However, akin to various particulates, extensive agglomeration of nanoclay in polymer matrices presents difficulties in its utilization. In this study, we implement a multi-scale approach to characterize the dispersion of three different types of nanoclays. Cloisite® 15A, 25A and 30B are individually mixed with Epon 815C epoxy resin, by the aid of a sonicator. The resin/nanoclay compound is then mixed with Epi-cure 3282 curing agent and injected into center-gated disk shaped molds. The dispersion state of nanoclay is characterized by using samples cut along the radius of the molded composite disks. Nanoclay clusters larger than 1.5µm are characterized by performing digital image analysis on the scanning electron micrographs, whereas smaller clusters are identified by wavelength dispersive spectrometry. In addition, intra-cluster structure is studied by transmission electron microscopy. It is found that the effectiveness of dispersion increases in the order of Cloisite® 15A, 25A and 30B. For instance the average content of clusters larger than 1.5µm is determined as 4.6vol.% for Cloisite® 15A, whereas the same value for 25A and 30B are 3.39vol.% and 3.45vol.%, respectively. The nanoclay clusters are observed to break down into smaller pieces in the flow direction, regardless of the nanoclay type. For example, small Cloisite® 30B clusters (Area<3µm2) make up 37.8% of the nanoclay content at the inlet, whereas the same value is calculated to be 46% at the outer edge of the disk. Several nano-voids are detected in the intra-cluster regions from the TEM images. These nano-voids are suspected to result from insufficient dispersion of nanoclay in epoxy matrix.YesPeer reviewed and presented at the 25th Oklahoma AIAA/ASME Symposium

Useful scars: Physics of the capsids of archaeal viruses

We propose a physical model for the capsids of tailed archaeal viruses as viscoelastic membranes under tension. The fluidity is generated by thermal motion of scarlike structures that are an intrinsic feature of the ground state of large particle arrays covering surfaces with nonzero Gauss curvature. The tension is generated by a combination of the osmotic pressure of the enclosed genome and an extension force generated by filamentous structure formation that drives the formation of the tails. In continuum theory, the capsid has the shape of a surface of constant mean curvature: an unduloid. Particle arrays covering unduloids are shown to exhibit pronounced subdiffusive and diffusive single-particle transport at temperatures that are well below the melting temperature of defect-free particle arrays on a surface with zero Gauss curvature

Integrating Supply Chain and Facility Risk Analyses For Improved Business Decisions

PresentationTypically, business supply chain risks are managed separately from fixed facility risks. However, where significant fixed site risk reduction can negatively impact a supply chain, a study that addresses both the supply chain and fixed facility risk can be done to help the business integrate all available information into the decision process. To assure a comprehensive risk analysis, a supply chain risk study should include rare/high consequence events, as does the fixed site study. A case study is presented for a facility that imports, stores, and consumes large volumes of a highly toxic material, and is located in a densely populated area. The methods used to analyze risks and identify risk reduction opportunities for the facility and the supply chain are described. The business team integrates the results of this study with other information to make better decisions

Useful scars: Physics of the capsids of archaeal viruses.

We propose a physical model for the capsids of tailed archaeal viruses as viscoelastic membranes under tension. The fluidity is generated by thermal motion of scarlike structures that are an intrinsic feature of the ground state of large particle arrays covering surfaces with nonzero Gauss curvature. The tension is generated by a combination of the osmotic pressure of the enclosed genome and an extension force generated by filamentous structure formation that drives the formation of the tails. In continuum theory, the capsid has the shape of a surface of constant mean curvature: an unduloid. Particle arrays covering unduloids are shown to exhibit pronounced subdiffusive and diffusive single-particle transport at temperatures that are well below the melting temperature of defect-free particle arrays on a surface with zero Gauss curvature

Regulation of type-II collagen gene expression during human chondrocyte de-differentiation and recovery of chondrocyte-specific phenotype in culture involves Sry-type high-mobility-group box (SOX) transcription factors.

During ex vivo growth as monolayer cultures, chondrocytes proliferate and undergo a process of de-differentiation. This process involves a change in morphology and a change from expression of chondrocyte-specific genes to that of genes that are normally expressed in fibroblasts. Transfer of the monolayer chondrocyte culture to three-dimensional culture systems induces the cells to re-acquire a chondrocyte-specific phenotype and produce a cartilaginous-like tissue in vitro. We investigated mechanisms involved in the control of the de-differentiation and re-differentiation process in vitro. De-differentiated chondrocytes re-acquired their chondrocyte-specific phenotype when cultured on poly-(2-hydroxyethyl methacrylate) (polyHEMA) as assayed by morphology, reverse transcriptase PCR of chondrocyte-specific mRNA, Western-blot analysis and chondrocyte-specific promoter activity. Essentially, full recovery of the chondrocyte-specific phenotype was observed when cells that had been cultured for 4 weeks on plastic were transferred to culture on polyHEMA. However, after subsequent passages on plastic, the phenotype recovery was incomplete or did not occur. The activity of a gene reporter construct containing the promoter and enhancer from the human type-II collagen gene (COL2A1) was modulated by the culture conditions, so that its transcriptional activity was repressed in monolayer cultures and rescued to some extent when the cells were switched to polyHEMA cultures. The binding of Sry-type high-mobility-group box (SOX) transcription factors to the enhancer region was modulated by the culture conditions, as were the mRNA levels for SOX9. A transfected human type-II collagen reporter construct was activated in de-differentiated cells by ectopic expression of SOX transcription factors. These results underscore the overt change in phenotype that occurs when chondrocytes are cultured as monolayers on tissue-culture plastic substrata