264 research outputs found

    Methods for managing uncertainly in material selection decisions : robustness of early stage life cycle assessment

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    Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.On title page "[Allen]" penciled in.Includes bibliographical references (p. 75-79).Utilizing alternative materials is an important tactic to improve the environmental performance of products. Currently a growing array of materials candidates confronts today's product designer. While life-cycle assessment (LCA) methods provide quantitative input into this selection decision, their implementations are evolving and disparate. The goal of this paper is to explore several major analytical variations of LCA implementations and the implications of these variants across a range of application contexts. Specifically, this thesis examines analytical variations in valuation method and treatment of recycling by exploring allocation methods that affect product end-of-life. An abstracted case study across a range of materials is presented, including materials that exhibit a spectrum in variation of environmental performance and material degradation between primary and secondary applications. To date, research has shown that the amount of recycled material delivered by, or used in, the life cycle of a product will affect the environmental burdens of other product life cycles. However, explicit consideration has not been given to the question of whether end-of-life allocation methods can lead to different materials selection decisions in early stage product development cycles. Similarly stemming from this question is the issue of, if so, how do these allocation methods differentially favor certain material classes? Results indicate that the choice of analytical method as well as its underlying parameters can have substantial impact on individual metrics that determine environmentally preferred material and that there are sets of analytical variation over which strategic results are strongly affected.by Anna L. Nicholson.S.M.S.M.in Technology and Polic

    Anatomically Correct: Implementing and Evaluating an Educational Digital Game for Applied Sciences Students

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    Digital games are a common form of entertainment in modern society and are increasingly prevalent in health education. However, little research has been conducted into their use for delivering anatomy and histology education for health students. This is surprising considering the difficulty many health students have learning anatomy and histology. The study used a mixed methodology, consisting of a controlled trial and qualitative evaluation of learner attitudes towards the digital game. The trial stratified learners into two groups: a digital game group and a multiple-choice quiz group, for one semester. At the end of semester final examination results from the two groups were compared to see if the digital game was a comparable means of revising anatomy and histology subject matter. Additionally, an online survey and semi-structured interviews were used to explore student attitudes towards the digital game. Findings demonstrated that a digital game could be as effective as alternative methods to support revision of anatomy subject matter. Further, results post-intervention survey (n=10) and semi-structured interviews (n=6) showed that students were interested in the use of digital games to support revision and enjoyed their experiences using the digital game during their studies

    Research methods of Talking About The Smokes: an International Tobacco Control Policy Evaluation Project study with Aboriginal and Torres Strait Islander Australians

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    Objective: To describe the research methods and baseline sample of the Talking About The Smokes (TATS) project.Design: The TATS project is a collaboration between research institutions and Aboriginal community-controlled health services (ACCHSs) and their state and national representative bodies. It is one of the studies within the International Tobacco Control Policy Evaluation Project, enabling national and international comparisons. It includes a prospective longitudinal study of Aboriginal and Torres Strait Islander smokers and recent ex-smokers; a survey of non-smokers; repeated cross-sectional surveys of ACCHS staff; and descriptions of the tobacco policies and practices at the ACCHSs. Community members completed face-to-face surveys; staff completed surveys on paper or online. We compared potential biases and the distribution of variables common to the main community baseline sample and unweighted and weighted results of the 2008 National Aboriginal and Torres Strait Islander Social Survey (NATSISS). The baseline survey (Wave 1) was conducted between April 2012 and October 2013.Setting and participants: 2522 Aboriginal and Torres Strait Islander people in 35 locations (the communities served by 34 ACCHSs and one community in the Torres Strait), and 645 staff in the ACCHSs.Main outcome measures: Sociodemographic and general health indicators, smoking status, number of cigarettes smoked per day and quit attempts.Results: The main community baseline sample closely matched the distribution of the Aboriginal and Torres Strait Islander population in the weighted NATSISS by age, sex, jurisdiction and remoteness. There were inconsistent differences in some sociodemographic factors between our sample and the NATSISS: our sample had higher proportions of unemployed people, but also higher proportions who had completed Year 12 and who lived in more advantaged areas. In both surveys, similar percentages of smokers reported having attempted to quit in the past year, and daily smokers reported similar numbers of cigarettes smoked per day.Conclusion: The TATS project provides a detailed and nationally representative description of Aboriginal and Torres Strait Islander smoking behaviour, attitudes, knowledge and exposure to tobacco control activities and policies, and their association with quitting

    Single Nucleotide Polymorphism Analysis Indicates Genetic Distinction and Reduced Diversity of Swine-Associated Methicillin Resistant Staphylococcus aureus (MRSA) ST5 Isolates Compared to Clinical MRSA ST5 Isolates

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    Livestock associated methicillin resistant S. aureus (LA-MRSA) are lineages adapted to livestock species. LA-MRSA can be transmitted to humans and public health concerns exist because livestock may be the largest MRSA reservoir outside of hospital settings. Although the predominant European (ST398) and Asian (ST9) lineages of LA-MRSA are considered livestock adapted, North American swine also harbor ST5, a globally disseminated and highly pathogenic lineage. This study applied whole genome sequencing and single nucleotide polymorphism (SNP) typing to compare the population structure and genetic relatedness between swine associated and human clinical MRSA ST5 isolates. The established high-resolution phylogenomic framework revealed that LA-MRSA and human clinical MRSA ST5 are genetically distinct. LA-MRSA isolates were found to be clonal within farms, while greater genome diversity was observed among sampled clinical MRSA ST5. Analysis of the accessory genome demonstrated that LA-MRSA ST5 isolates and clinical MRSA ST5 isolates harbor different AMR genes and virulence factors, consistent with the SNP analysis. Collectively, our data indicate LA-MRSA and clinical MRSA ST5 isolates are distinct and the swine reservoir is likely of minimal significance as a source of clinical MRSA ST5 infections

    The stem cell organisation, and the proliferative and gene expression profile of Barrett's epithelium, replicates pyloric-type gastric glands

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    Objective: Barrett's oesophagus shows appearances described as ‘intestinal metaplasia’, in structures called ‘crypts’ but do not typically display crypt architecture. Here, we investigate their relationship to gastric glands. Methods: Cell proliferation and migration within Barrett's glands was assessed by Ki67 and iododeoxyuridine (IdU) labelling. Expression of mucin core proteins (MUC), trefoil family factor (TFF) peptides and LGR5 mRNA was determined by immunohistochemistry or by in situ hybridisation, and clonality was elucidated using mitochondrial DNA (mtDNA) mutations combined with mucin histochemistry. Results: Proliferation predominantly occurs in the middle of Barrett's glands, diminishing towards the surface and the base: IdU dynamics demonstrate bidirectional migration, similar to gastric glands. Distribution of MUC5AC, TFF1, MUC6 and TFF2 in Barrett's mirrors pyloric glands and is preserved in Barrett's dysplasia. MUC2-positive goblet cells are localised above the neck in Barrett's glands, and TFF3 is concentrated in the same region. LGR5 mRNA is detected in the middle of Barrett's glands suggesting a stem cell niche in this locale, similar to that in the gastric pylorus, and distinct from gastric intestinal metaplasia. Gastric and intestinal cell lineages within Barrett's glands are clonal, indicating derivation from a single stem cell. Conclusions: Barrett's shows the proliferative and stem cell architecture, and pattern of gene expression of pyloric gastric glands, maintained by stem cells showing gastric and intestinal differentiation: neutral drift may suggest that intestinal differentiation advances with time, a concept critical for the understanding of the origin and development of Barrett's oesophagus

    Signatures of TOP1 transcription-associated mutagenesis in cancer and germline

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    The mutational landscape is shaped by many processes. Genic regions are vulnerable to mutation but are preferentially protected by transcription-coupled repair1. In microorganisms, transcription has been demonstrated to be mutagenic2,3; however, the impact of transcription-associated mutagenesis remains to be established in higher eukaryotes4. Here we show that ID4—a cancer insertion–deletion (indel) mutation signature of unknown aetiology5 characterized by short (2 to 5 base pair) deletions —is due to a transcription-associated mutagenesis process. We demonstrate that defective ribonucleotide excision repair in mammals is associated with the ID4 signature, with mutations occurring at a TNT sequence motif, implicating topoisomerase 1 (TOP1) activity at sites of genome-embedded ribonucleotides as a mechanistic basis. Such TOP1-mediated deletions occur somatically in cancer, and the ID-TOP1 signature is also found in physiological settings, contributing to genic de novo indel mutations in the germline. Thus, although topoisomerases protect against genome instability by relieving topological stress6, their activity may also be an important source of mutations in the human genome.We thank S. Jinks-Robertson for suggesting the traffic light reporter approach; H. Klein for guidance on fluctuation assays; R. van Boxtel for sharing sequencing data for MLH1-KO organoids; A. Bretherick, O. B. Reina and G. Kudla for advice on HygroR re-coding; staff at the IGC core services (L. Murphy, C. Nicol, C. Warnock, E. Freyer, S. Brown and J. Joseph), C. Logan, A. Fluteau, A. Robertson and the staff at Edinburgh Genomics for technical assistance; staff at Liverpool CLL Biobank (funded by Blood Cancer UK) for samples used to generate GEL WGS data; A. Ewing, C.-A. Martin, N. Hastie and W. Bickmore for discussions. Funding for this work: UK Medical Research Council Human Genetics Unit core grants (MC_UU_00007/5 to A.P.J., MC_UU_00007/11 to M.S.T.); Edinburgh Clinical Academic Track PhD programme (Wellcome Trust 204802/Z/16/Z) to T.C.W.; 2021 AACR-Amgen Fellowship in Clinical/Translational Cancer Research (grant number 21-40-11-NADE) to F.N.; a CRUK Brain Tumour Centre of Excellence Award (C157/A27589) to M.D.N.; EKFS research grant (2019_A09), Wilhelm Sander-Stiftung (2019.046.1) to K.A., CRUK programme grant (C20807/A2864) to T.S.; La Caixa Foundation (CLLEvolution-LCF/PR/HR17/52150017, Health Research 2017 Program HR17-00221) to E.C.; E.C. is an Academia Researcher of the Institució Catalana de Recerca i Estudis Avançats of the Generalitat de Catalunya. Edinburgh Genomics is partly supported by NERC (R8/H10/56), MRC (MR/K001744/1) and BBSRC (BB/J004243/1). This research was made possible through access to the data and findings generated by the 100,000 Genomes Project. The 100,000 Genomes Project is managed by Genomics England Limited (a wholly owned company of the Department of Health and Social Care). The 100,000 Genomes Project is funded by the National Institute for Health Research and NHS England. The Wellcome Trust, Cancer Research UK and the Medical Research Council have also funded research infrastructure. The 100,000 Genomes Project uses data provided by patients and collected by the National Health Service as part of their care and support.Peer Reviewed"Article signat per 22 autors/es: Martin A. M. Reijns, David A. Parry, Thomas C. Williams, Ferran Nadeu, Rebecca L. Hindshaw, Diana O. Rios Szwed, Michael D. Nicholson, Paula Carroll, Shelagh Boyle, Romina Royo, Alex J. Cornish, Hang Xiang, Kate Ridout, The Genomics England Research Consortium, Colorectal Cancer Domain UK 100,000 Genomes Project, Anna Schuh, Konrad Aden, Claire Palles, Elias Campo, Tatjana Stankovic, Martin S. Taylor & Andrew P. Jackson "Postprint (published version

    Signatures of TOP1 transcription-associated mutagenesis in cancer and germline

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    The mutational landscape is shaped by many processes. Genic regions are vulnerable to mutation but are preferentially protected by transcription-coupled repair1. In microorganisms, transcription has been demonstrated to be mutagenic2,3; however, the impact of transcription-associated mutagenesis remains to be established in higher eukaryotes4. Here we show that ID4—a cancer insertion–deletion (indel) mutation signature of unknown aetiology5 characterized by short (2 to 5 base pair) deletions —is due to a transcription-associated mutagenesis process. We demonstrate that defective ribonucleotide excision repair in mammals is associated with the ID4 signature, with mutations occurring at a TNT sequence motif, implicating topoisomerase 1 (TOP1) activity at sites of genome-embedded ribonucleotides as a mechanistic basis. Such TOP1-mediated deletions occur somatically in cancer, and the ID-TOP1 signature is also found in physiological settings, contributing to genic de novo indel mutations in the germline. Thus, although topoisomerases protect against genome instability by relieving topological stress6, their activity may also be an important source of mutations in the human genome

    RUNX3 overexpression inhibits normal human erythroid development

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    RUNX proteins belong to a family of transcription factors essential for cellular proliferation, differentiation, and apoptosis with emerging data implicating RUNX3 in haematopoiesis and haematological malignancies. Here we show that RUNX3 plays an important regulatory role in normal human erythropoiesis. The impact of altering RUNX3 expression on erythropoiesis was determined by transducing human CD34+ cells with RUNX3 overexpression or shRNA knockdown vectors. Analysis of RUNX3 mRNA expression showed that RUNX3 levels decreased during erythropoiesis. Functionally, RUNX3 overexpression had a modest impact on early erythroid growth and development. However, in late-stage erythroid development, RUNX3 promoted growth and inhibited terminal differentiation with RUNX3 overexpressing cells exhibiting lower expression of glycophorin A, greater cell size and less differentiated morphology. These results suggest that suppression of RUNX3 is required for normal erythropoiesis. Overexpression of RUNX3 increased colony formation in liquid culture whilst, corresponding RUNX3 knockdown suppressed colony formation but otherwise had little impact. This study demonstrates that the downregulation of RUNX3 observed in normal human erythropoiesis is important in promoting the terminal stages of erythroid development and may further our understanding of the role of this transcription factor in haematological malignancies
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