Synthesis and characterisation of high silica zeolites for methane reforming

In this study, the ability of the MTBA cation to effectively direct the formation of the nanosized MFI framework was present for the first time. Two nanosized materials from different SDAs were synthesised and investigated with a variety of different analytical techniques to ascertain the mechanism of formation. X-ray diffraction and dynamic light scattering studies showed varying results between the TPA and MTBA SDAs used, with the TPA templated material suggesting rapid crystallisation and the MTBA template material suggesting an aggregation mechanism. 13C and 29Si SSNMR studies of both materials suggest a spontaneous crystallisation mechanism is taking place. Conclusive evidence of a mechanism of formation was not observed, however it was concluded that the most likely mechanism was that of spontaneous rapid crystallisation. Further work into the mechanism of crystallisation needs to be conducted with a focus on size control and the effect of the SDA used. The effect of crystallite size and framework topology on the catalysis of methane reforming was also studied using incorporated nickel as the active species. The catalytic activities for a nano sized and a micron sized nickel containing MFI zeolite were tested. The nano sized material was found to have a higher activity for the partial oxidation of methane, whereas the micron sized material was found to have a higher activity for the biogas reforming of methane. The catalytic activity for nickel containing MEL and MTW type materials was also tested. The MTW material showed a much higher activity for all methane reforming when compared to the MEL material. For the partial oxidation of methane, the MTW nickel containing material showed the highest activity, and for biogas reforming the micron sized MFI material showed the highest activity. It was concluded that the zeolite framework plays an important role in the catalysis of methane reforming and is not simply acting as a support for the active nickel species as the non- ‘doped’ materials show no catalytic activity. The effect of crystallite size is not shown to be equal for all reforming reactions. Further work into the location and activity of the nickel species with the framework needs to be conducted along with additional investigations into the wide variety of framework topologies available

Quantitative analysis of DNA methylation at all human imprinted regions reveals preservation of epigenetic stability in adult somatic tissue.

BACKGROUND: Genes subject to genomic imprinting are mono-allelically expressed in a parent-of-origin dependent manner. Each imprinted locus has at least one differentially methylated region (DMR) which has allele specific DNA methylation and contributes to imprinted gene expression. Once DMRs are established, they are potentially able to withstand normal genome reprogramming events that occur during cell differentiation and germ-line DMRs are stably maintained throughout development. These DMRs, in addition to being either maternally or paternally methylated, have differences in whether methylation was acquired in the germ-line or post fertilization and are present in a variety of genomic locations with different Cytosine-phosphate guanine (CpG) densities and CTCF binding capacities. We therefore examined the stability of maintenance of DNA methylation imprints and determined the normal baseline DNA methylation levels in several adult tissues for all imprinted genes. In order to do this, we first developed and validated 50 highly specific, quantitative DNA methylation pyrosequencing assays for the known DMRs associated with human imprinted genes. RESULTS: Remarkable stability of the DNA methylation imprint was observed in all germ-line DMRs and paternally methylated somatic DMRs (which maintained average methylation levels of between 35% - 65% in all somatic tissues, independent of gene expression). Maternally methylated somatic DMRs were found to have more variation with tissue specific methylation patterns. Most DMRs, however, showed some intra-individual variability for DNA methylation levels in peripheral blood, suggesting that more than one DMR needs to be examined in order to get an overall impression of the epigenetic stability in a tissue. The plasticity of DNA methylation at imprinted genes was examined in a panel of normal and cancer cell lines. All cell lines showed changes in DNA methylation, especially at the paternal germ-line and the somatic DMRs. CONCLUSIONS: Our validated pyrosequencing methylation assays can be widely used as a tool to investigate DNA methylation levels of imprinted genes in clinical samples. This first comprehensive analysis of normal methylation levels in adult somatic tissues at human imprinted regions confirm that, despite intra-individual variability and tissue specific expression, imprinted genes faithfully maintain their DNA methylation in healthy adult tissue. DNA methylation levels of a selection of imprinted genes are, therefore, a valuable indicator for epigenetic stability.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

“I’m always the unusual one”: exploring the dialogic identities of male primary teachers

During the past two decades, there has been a drive towards the recruitment of primary teachers from diverse backgrounds and experiences, including more men. Nevertheless, in 2016, 85% of teachers working in primary and nursery settings were female (DfE, 2017a), more men drop out of teacher training than women, although proportionally more are found in school leadership roles (DfE, 2017a). In order to bring meaning to teacher workforce statistics, research directs focus to male primary teachers’ identities, claiming that dominant discourses pressurise men to display typical masculine behaviour within a feminised environment. The discourse positions men as ‘high flyers’, legitimising their career choice and swift promotion into management – by presenting them as role models for problematic boys, or as vulnerable in the workplace, struggling with a negative discourse that places them under scrutiny. This thesis adds to our understanding of men’s experience in the female-dominated space of the primary school through an exploration of the identity development and enactment of a group of male students as they progress from their final undergraduate year leading to qualified teacher status into their first year of teaching and beyond. Framing their narratives of becoming a teacher within Holland et al.’s (1998) theory of ‘Figured Worlds’, this thesis moves beyond assumption of fixed identities and performances that are determined by dominant gender discourses towards an emphasis on the dialogic nature of identity development: an ongoing ‘self-in-practice’. It explores how the culture of the primary school is characterised by particular figures and values, where dominant discourses and narratives of self - make available and legitimise particular positional identities and performances for male teachers. I argue that when men first enter primary schools they demonstrate resistance to their discursive positioning as ‘unsuitable’, negotiating hegemonic masculine discourse in order to reposition themselves as a successful teacher and valued male role model. However, over a time-frame of three years, my participants were able to create nuanced dialogic responses to their position within the primary school environment, beginning to disrupt prevailing discursive identities, and form their “own opinions” about what it means to be a male primary teacher

The identity dilemmas of Early Career Teachers from under-represented groups in the UK

Uncontested narratives of normality in primary teacher training are located and demonstrated in heteronormativity, whiteness, able-bodiedness and femininity. Early-Career Teachers who know and feel they lie outside of these are positioned uneasily as they try to locate spaces to express their identities and enable self-agency. This article explores how beginning teachers from under-represented groups come to understand themselves and others during the process of becoming a primary teacher. Through qualitative analysis of video stories of 12 novice primary teachers, we identified salient themes including dilemmas around identity invisibility/hypervisibility and lack of agency to (re)construct their identities. Our findings have implications for teacher educators and school leaders to provide new teachers opportunities to explore their identity dilemmas alongside their peers in safe spaces. Developing provision that builds beginning teachers’ peer networks alongside their understanding of self may not only offer an outlet for self-agency but impact on teacher retention from those located in under-represented groups

Control of set-up dominant multivariate manufacturing processes

A practical control chart is introduce, called multivariate Set-Up Process Algorithm (m-SUPA), which can be used to signal when a process is statistically off-target. This control chart uses a traffic light system to provide simple information to an operator about how close a measured part is to its global target. The chart works with a simple rule set resulting in process adjustments at a calculated point, rather than relying on rule-of-thumb methods. A final consideration is calculating the size of process adjustment, when one control adjustment has multiple effects on different design features. Simple feedback controllers are suggested for calculating process adjustments, providing consistency to an action taken. Simulation results suggest that m-SUPA with adjustments based on this kind of controllers is able to steer the process to a desired performance region

Replication factory activation can be decoupled from the replication timing program by modulating Cdk levels

In the metazoan replication timing program, clusters of replication origins located in different subchromosomal domains fire at different times during S phase. We have used Xenopus laevis egg extracts to drive an accelerated replication timing program in mammalian nuclei. Although replicative stress caused checkpoint-induced slowing of the timing program, inhibition of checkpoint kinases in an unperturbed S phase did not accelerate it. Lowering cyclin-dependent kinase (Cdk) activity slowed both replication rate and progression through the timing program, whereas raising Cdk activity increased them. Surprisingly, modest alteration of Cdk activity changed the amount of DNA synthesized during different stages of the timing program. This was associated with a change in the number of active replication factories, whereas the distribution of origins within active factories remained relatively normal. The ability of Cdks to differentially effect replication initiation, factory activation, and progression through the timing program provides new insights into the way that chromosomal DNA replication is organized during S phase

Chromosome-wide identification of novel imprinted genes using microarrays and uniparental disomies

Genomic imprinting refers to a specialized form of epigenetic gene regulation whereby the expression of a given allele is dictated by parental origin. Defining the extent and distribution of imprinting across genomes will be crucial for understanding the roles played by imprinting in normal mammalian growth and development. Using mice carrying uniparental disomies or duplications, microarray screening and stringent bioinformatics, we have developed the first large-scale tissue-specific screen for imprinted gene detection. We quantify the stringency of our methodology and relate it to previous non-tissue-specific large-scale studies. We report the identification in mouse of four brain-specific novel paternally expressed transcripts and an additional three genes that show maternal expression in the placenta. The regions of conserved linkage in the human genome are associated with the Prader–Willi Syndrome (PWS) and Beckwith–Wiedemann Syndrome (BWS) where imprinting is known to be a contributing factor. We conclude that large-scale systematic analyses of this genre are necessary for the full impact of genomic imprinting on mammalian gene expression and phenotype to be elucidated

Homelessness and health needs in Wales

Background Public Health Wales developed its long-term strategy with the purpose of ‘Working to Achieve a Healthier Future for Wales’. This study is motivated by one of the strategic priorities, ‘Influencing the wider determinants of health’ with an emphasis on homelessness prevention. Main Aim To understand health needs of homeless health service users from routinely collected health data in Wales. To quantify the corresponding differences from general population. Methods Scoping work has completed collaborating with academic researchers, third sectors, clinical professionals, Office for National Statistics, and housing stats of Welsh Government. To construct study cohort, we will perform linkage exercise among Annual District Death Extract, Emergency Department Data Set, Outpatient Dataset for Wales, Patient Episode Database for Wales, Substance Misuse Data Set and Welsh Longitudinal General Practice dataset (from 2007 to 2018) stored in Secure Anonymised Information Linkage (SAIL) Databank. Study cohort includes all patients with an indication (i.e. clinical codes) of homelessness in their registration information and/or health records. We propose to adapt propensity score matching to construct matched case and control groups. This method will assign each homeless individual to individual without homeless flag with same or similar propensity score. We will then proceed to test for the significance of the homelessness and each health and wellbeing indicators (i.e. physical health, mental wellbeing and substance misuse) in the presence of confounders, and estimate the effects of homelessness on these indicators. Results This study will demonstrate how linked data provide a more comprehensive review of the health needs of a vulnerable population, the homeless groups in Wales, and be able to explore changes over time. Conclusion The relationship between homelessness and health issues is bi-directional. Findings from this study will have implications for health, housing, social, and homelessness policy at both local and national level; as well as contributing to the ability to providing tailored health services to targeted homeless populations groups