Variations in low-grade wood modification and stress lamination

Sitka spruce (Picea sitchensis) trees in UK forests are expected to yield nearly 30% more softwood than current levels in the coming decades. These are relatively fast-growing trees, yielding low-grade wood that is incompatible with standards for glue-based lamination. Alongside this forecasted increase, there is a major worldwide shift towards building taller and faster with massive laminated and engineered wood products, mainly as substitutes for steel and concrete. For making the best use of the expected increase in UK softwood and also to expand the scope of tall wood construction, alternative ways of working with low-grade wood are needed, along with developing new variations of existing techniques in processing and construction. This thesis examines two strategies: wood modification by impregnation and stress lamination. The former involves treating wood under pressure in a liquid solution. Once impregnated, the liquid is then solidified in-situ, grafting onto the wood to enhance its properties through direct molecular interactions in the cell wall. While wood treatments are usually done to increase durability, literature and preliminary small-scale testing suggest that impregnation can also lead to increases in stiffness and strength. Compared to wood modification, stress lamination is a relatively simple yet effective technique, and is useful for laminating wood without glue. Although widely used in timber bridges, stress lamination has found little to no application in buildings, primarily due to concerns regarding losses in prestress levels from creep and the moisture-related movement and shrinkage of wood. Scale models and testing emphasise the technique’s potential for both standard and bespoke structural elements for buildings. Full-scale detailing, construction, and testing of straight columns further establishes structural performance and feasibility. Test results from shearing five full-scale stress-laminated connections show performance beyond that of conventional mechanical fasteners. Twenty-five columns were also tested at full-scale, showing comparable buckling performance to Eurocode estimates for solid timber. Examples from literature and a new detail with overdried hardwood plates, tested during a six-month period, demonstrate that prestress losses can be mitigated to ensure long-term reliability in buildings. The full-scale testing performed in this thesis therefore highlights the usefulness, performance, and reliability of stress lamination with low-grade wood for multi-storey construction.UK Engineering and Physical Sciences Research Council (EPSRC) Cambridge Commonwealth Trust Ramboll Foundation Natural Sciences and Engineering Research Council of Canada (NSERC

Academic Libraries and Learning Support in Collaboration. Library Based Guidance for Peer Assisted Learning Leaders at Bournemouth University: Theory and Practice.

This article begins with an overview of the University’s pioneering Peer Assisted Learning Scheme (PAL) and describes how in 2005/6, the Library became involved, collaborating with the PAL Coordinator to develop materials for use by PAL Leaders. PAL is intended to foster cross-year support between students on the same course. It encourages students to support each other and learn co-operatively under the guidance of trained students from the year above - called PAL Leaders. Two documents were produced to support and empower these leaders. The first, Using the Library for Your Research, provides leaders with key guidance information on the University Library, its resources and the services it provides. The second, Citing References Using the Harvard System, aims to explain and demystify the Harvard Referencing system and to encourage good referencing habits from an early stage of their course through a practical hands-on exercise. Feedback from PAL Leaders continues to inform the development of these guidance materials, in particular the referencing exercise which was reworked to better suit the needs of the leaders delivering it

Mouse maternal systemic inflammation at the zygote stage causes blunted cytokine responsiveness in lipopolysaccharide-challenged adult offspring

These results demonstrate for the first time that the preimplantation embryo in vivo is sensitive to maternal systemic inflammation, with effects on blastocyst cell lineage allocation and consequences for behaviour, adiposity and innate immune response in adult offspring. Critically, we identify a novel mechanism mediated through maternal-embryonic interactions that confers plasticity in the development of the innate immune system, which is potentially important in setting postnatal tolerance to environmental pathogens. Our study extends the concept of developmental programming of health and disease to include maternal health at the time of conceptio

A novel human iPSC model of COL4A1/A2 small vessel disease unveils a key pathogenic role of matrix metalloproteinases

Cerebral small vessel disease (SVD) affects the small vessels in the brain and is a leading cause of stroke and dementia. Emerging evidence supports a role of the extracellular matrix (ECM), at the interface between blood and brain, in the progression of SVD pathology, but this remains poorly characterized. To address ECM role in SVD, we developed a co-culture model of mural and endothelial cells using human induced pluripotent stem cells from patients with COL4A1/A2 SVD-related mutations. This model revealed that these mutations induce apoptosis, migration defects, ECM remodeling, and transcriptome changes in mural cells. Importantly, these mural cell defects exert a detrimental effect on endothelial cell tight junctions through paracrine actions. COL4A1/A2 models also express high levels of matrix metalloproteinases (MMPs), and inhibiting MMP activity partially rescues the ECM abnormalities and mural cell phenotypic changes. These data provide a basis for targeting MMP as a therapeutic opportunity in SVD.</p