Synthesis of nitrogen-substituted cycloparaphenylenes

Bottom-up synthesis is increasingly becoming the method of choice for assembling and studying novel nanomaterials. Whereas more traditional top-down methods may lead to mixtures of products and suffer from reproducibility issues, bottom-up approaches offer atomistic control over the material's structure. Bottom-up synthesis can also produce materials that would otherwise be unobtainable with top-down methodologies. Finite substructures of carbon nanotubes (CNTs) are one such example. The work encompassed in this thesis details the study of two related classes of CNT substructures: the cycloparaphenylenes (CPPs) and [5.7]ncyclacenes. Cycloparaphenylenes are a class of graphitic material with many unique properties that make them intriguing candidates for study in a variety of electronic applications. Chapter 1 describes the current state of CPP research, from preliminary synthesis to fundamental understanding of their properties. To optimize device performance, carbon materials are often doped with heteroatoms. Towards this end, the synthesis of a series of nitrogen-doped [8]CPPs (N-[8]CPPs) are detailed in Chapter 2. Nitrogen is incorporated into the CPP structure by way of the reductive aromatization strategy used for the all carbon CPPs, replacing 1,4-dibromobenzene with 2,5-dibromopyridine. The synthesis utilizes oxidatively masked benzenes to assemble less strained, macrocyclic precursors. Through the divergent nature of the synthesis, macrocycles containing up to three nitrogen atoms at precise locations are prepared. Macrocycles are aromatized via a single electron reduction to reveal the final N-CPP structures. Chapter 3 details the full characterization of the properties of the novel N-[8]CPPs. The differences between the N-[8]CPPs and [8]CPP are rationalized in the context of DFT studies. Finally, the study of 1N-[8]CPP and [8]CPP as novel electrode materials in supercapacitor cells is presented. Preliminary results show that the CPP electrodes are more conductive than the activated carbon control group, but the specific capacitances are found to be low. Finally, Chapter 4 describes the computational study of a novel family of macrocycle: [5.7]ncyclacenes. [5.7]ncyclacenes are isomers of the sought after [n]cyclacenes. Unlike their isomeric cousins, DFT studies show that [5.7]ncyclacenes have stable, closed-shell singlet ground states with relatively low strain energies. NICS values also show the molecules to be non-aromatic. These results suggest that with proper synthetic design, the [5.7]ncyclacenes should be accessible synthetically

Repositioning academic literacy: charting the emergence of a community of practice

This paper reflects on the experiences of the authors in planning and teaching a short-course in academic literacy for students enrolled in the first year of an education degree. By conceptualising tertiary literacy as a social practice and drawing on a sociocultural approach to learning, the members of the project team were able to move beyond deficit views of individual students towards a consideration of their own teaching practices and how they could best help students expand their literate repertoires. This approach provided opportunities for the team to focus on pedagogical matters and to chart its own emergence as a community of practice working on a shared problem

Use of crushed brick in reinforced earth railway structures

The Bermondsey Dive-Under Scheme is a key part of the Thameslink Programme which will remove the existing bottleneck that severely limits the number of trains that can pass through London Bridge Station. The scheme involves extensive demolition of 900m of masonry viaduct followed by the construction of 900m of new structures, 200m of reinforced earth structures, and 200m of embankment widening and raising. This paper describes a study undertaken in 2012 that examined the viability of recycling the demolished brickwork material into a crushed engineered fill material for use in the permanent works. The overarching objective of the study was to seek to reduce the significant volumes of both imported fill and exported demolition material that would be required for the BDU scheme. In addition to the associated sustainability benefits, the significant reduction in lorry movements from London’s congested streets would result in significant environmental and safety benefits. The paper details the sampling and testing of brickwork that was undertaken as part of the study and presents the findings from the study. A synopsis of the properties of the crushed brick and the material requirements for engineered fill is included. The paper also discusses some of the issues associated with introducing innovation within major works programmes. The Bermondsey Dive Under Scheme is currently under construction and is scheduled for completion in 2017.</p

Understanding the physiological and biological response to ambient heat exposure in pregnancy: protocol for a systematic review and meta-analysis

Introduction: Climate change increases not only the frequency, intensity and duration of extreme heat events but also annual temperatures globally, resulting in many negative health effects, including harmful effects on pregnancy and pregnancy outcomes. As temperatures continue to increase precipitously, there is a growing need to understand the underlying biological pathways of this association. This systematic review will focus on maternal, placental and fetal changes that occur in pregnancy due to environmental heat stress exposure, in order to identify the evidence-based pathways that play a role in this association. Methods and analysis: We will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We will search PubMed and Ovid Embase databases from inception using tested and validated search algorithms. Inclusion of any studies that involve pregnant women and have measured environmental heat stress exposure and either maternal, placental or fetal physiological or biochemical changes and are available in English. Modelling studies or those with only animals will be excluded. The risk of bias will be assessed using the Office of Health Assessment and Translation tool. Abstract screening, data extraction and risk of bias assessment will be conducted by two independent reviewers. Environmental parameters will be reported for each study and where possible these will be combined to calculate a heat stress indicator to allow comparison of exposure between studies. A narrative synthesis will be presented following standard guidelines. Where outcome measures have at least two levels of exposure, we will conduct a dose–response meta-analysis should there be at least three studies with the same outcome. A random effects meta-analysis will be conducted where at least three studies give the same outcome. Ethics and dissemination: This systematic review and meta-analysis does not require ethical approval. Dissemination will be through peer-reviewed journal publication and presentation at international conferences/interest groups. PROSPERO registration number: CRD42024511153

Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes

BACKGROUND: The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. RESULTS: Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and ‘Turbellaria’) contain methylated cytosines within their genome compartments. CONCLUSIONS: Collectively, these findings provide the first direct evidence for a functionally conserved and enzymatically active DNA methylation system throughout the Platyhelminthes. Defining how this epigenetic feature shapes phenotypic diversity and development within the phylum represents an exciting new area of metazoan biology

A ten-year follow-up of a study of memory for the attack of September 11, 2001: Flashbulb memories and memories for flashbulb events.

Within a week of the attack of September 11, 2001, a consortium of researchers from across the United States distributed a survey asking about the circumstances in which respondents learned of the attack (their flashbulb memories) and the facts about the attack itself (their event memories). Follow-up surveys were distributed 11, 25, and 119 months after the attack. The study, therefore, examines retention of flashbulb memories and event memories at a substantially longer retention interval than any previous study using a test-retest methodology, allowing for the study of such memories over the long term. There was rapid forgetting of both flashbulb and event memories within the first year, but the forgetting curves leveled off after that, not significantly changing even after a 10-year delay. Despite the initial rapid forgetting, confidence remained high throughout the 10-year period. Five putative factors affecting flashbulb memory consistency and event memory accuracy were examined: (a) attention to media, (b) the amount of discussion, (c) residency, (d) personal loss and/or inconvenience, and (e) emotional intensity. After 10 years, none of these factors predicted flashbulb memory consistency; media attention and ensuing conversation predicted event memory accuracy. Inconsistent flashbulb memories were more likely to be repeated rather than corrected over the 10-year period; inaccurate event memories, however, were more likely to be corrected. The findings suggest that even traumatic memories and those implicated in a community's collective identity may be inconsistent over time and these inconsistencies can persist without the corrective force of external influences.This is the author accepted manuscript. The final version is available from the American Psychological Association via http://dx.doi.org/10.1037/xge000005