10,169 research outputs found

    Maternal nutritional status, C1 metabolism and offspring DNA methylation: a review of current evidence in human subjects.

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    : Evidence is growing for the long-term effects of environmental factors during early-life on later disease susceptibility. It is believed that epigenetic mechanisms (changes in gene function not mediated by DNA sequence alteration), particularly DNA methylation, play a role in these processes. This paper reviews the current state of knowledge of the involvement of C1 metabolism and methyl donors and cofactors in maternal diet-induced DNA methylation changes in utero as an epigenetic mechanism. Methyl groups for DNA methylation are mostly derived from the diet and supplied through C1 metabolism by way of choline, betaine, methionine or folate, with involvement of riboflavin and vitamins B6 and B12 as cofactors. Mouse models have shown that epigenetic features, for example DNA methylation, can be altered by periconceptional nutritional interventions such as folate supplementation, thereby changing offspring phenotype. Evidence of early nutrient-induced epigenetic change in human subjects is scant, but it is known that during pregnancy C1 metabolism has to cope with high fetal demands for folate and choline needed for neural tube closure and normal development. Retrospective studies investigating the effect of famine or season during pregnancy indicate that variation in early environmental exposure in utero leads to differences in DNA methylation of offspring. This may affect gene expression in the offspring. Further research is needed to examine the real impact of maternal nutrient availability on DNA methylation in the developing fetus

    Vertical features in flux: Elevation, interiority and the Anthropocene disruption of South West Louisiana’s five salt dome land islands

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    © 2018 Institution for Marine and Island Cultures, Mokpo National University. While islands are clearly delineated from mainland locations by virtue of their encirclement by water, fixation on this element has led to an under-appreciation and related under-exploration of the comparability of islands to elevated terrestrial features such as hills, mountains and ridges. In this article we discuss the manner in which the five so-called salt dome ‘islands’ (SDIs) of south-western Louisiana exhibit a continuum of features across locations that range from an island (Belle) to a hill (Jefferson) with the remainder (Avery, Cote Blanche and Weeks) occupying positions within these dualities. Salt domes are landscape elements produced when areas of horizontal salt deposits are forced into the strata above, where they form dome shaped intrusions. Some of these distort the surface and protrude above flat areas of land as small hills. In the case of the five salt domes discussed in this article, their protrusion above the swamplands and drier flatlands of south-western Louisiana has resulted in their perception, identification and nomenclative representation as islands. In this article, we focus on the verticality and material spatiality of the SDIs and consider the ways in which their islandness has been effected by the commercial operations that have operated on/in them. Particular focus is given to various mining and related underground storage enterprises that have disrupted the physical nature of the salt domes’ subterranean spaces, the surface that covers them and surrounding land- and water-scapes. Verticality and interiority are identified as key – if often under-recognised – aspects of islandness in general and of the SDIs in particular

    The Emergent Role of the Social Designer

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    This paper responds to the Academic Design Management Conference, Design Management Futures theme. It answers questions relating to the way in which we think about the future of Design Management, and the way in which Design Management may need to adapt to the changing nature of design and new management theories. This piece draws on the work of an interdisciplinary team of researchers from the fields of Engineering, Sociology and Graphic Design, and their experience in the areas of user-engagement, anti-oppressive education/pedagogy and inclusive design. This position paper is a reflective piece that examines the value of designers, engineers and sociologists working together. It puts forward the question ‘What can designers and engineers learn from the emancipatory paradigm of the Social Scientist?’ Reflections from a UK-based team of undergraduate designers and engineers provide insight to their experience of engaging with the user through an inclusive design project. They cast light upon their experience of cross-faculty studies, interdisciplinary collaborations and both the challenges and benefits to working with different user groups. This paper concludes by examining the practical implications for Design Management, providing insights for Design Management education, research and practice

    The influence of cannabis smoke and cannabis vapour on simulated lung surfactant function under physiologically relevant conditions

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    The use of cannabis for medicinal/recreational purposes is widespread throughout the world. Smoke inhalation is known to cause airway irritation due to noxious substances (ie, benzene) within the mix. Thus, advanced vaporisation platforms (eg, Davinci IQ) have been developed to circumvent negative health implications. Here, we consider the impact that cannabis smoke and cannabis vapour have on simulated lung surfactant performance within a model pulmonary space (ie, 37°C, elevated humidity and related fluid hydrodynamics). In total, 50 mg of herbal material was ignited or placed within a Davinci IQ vaporiser with subsequent activation. The aliquots were collected and then analysed using gas chromatography‐mass spectroscopy for composition and cannabinoid (eg, Δ9‐tetrahydrocannabinol [Δ9‐THC]) concentration. The average content within cannabis smoke was 2.84% (0.07%, SD) Δ9‐THC, with the same for cannabis vapour being 0.88% (0.14%, SD). Aerosolised samples were transferred to the lung biosimulator. When compared with the pristine Curosurf system, challenge with cannabis smoke and cannabis vapour reduced the surface pressure term by 26% and 7% and increased film compressibility by 60% and 15% at 80% trough area, respectively. The net effect would be enhanced film elasticity and an increased work of breathing, being more pronounced on cannabis smoke inhalation. The trends noted were ascribed to two factors operating synergistically, namely the amount of Δ9‐THC (plus others) within the aerosolised samples and the associated toxicity profile. Further research is required to establish mass‐balance effects (ie, titrated outputs) along with detailed chemical profiling of material generated from the unrelated cannabis activation pathways

    Erratum: Gut resistome development in healthy twin pairs in the first year of life

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    Anomaly-Free Supersymmetric SO(2N+2)/U(N+1) sigma-Model Based on the SO(2N+1) Lie Algebra of the Fermion Operators

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    The extended supersymmetric (SUSY) sigma-model has been proposed on the bases of SO(2N+1) Lie algebra spanned by fermion annihilation-creation operators and pair operators. The canonical transformation, extension of an SO(2N) Bogoliubov transformation to an SO(2N+1) group, is introduced. Embedding the SO(2N+1) group into an SO(2N+2) group and using SO(2N+2)/U(N+1) coset variables, we have investigated the SUSY sigma-model on the Kaehler manifold, the coset space SO(2N+2)/U(N+1). We have constructed the Killing potential, extension of the potential in the SO(2N)/U(N) coset space to that in the SO(2N+2)/U(N+1) coset space. It is equivalent to the generalized density matrix whose diagonal-block part is related to a reduced scalar potential with a Fayet-Ilipoulos term. The f-deformed reduced scalar potential is optimized with respect to vacuum expectation value of the sigma-model fields and a solution for one of the SO(2N+1) group parameters has been obtained. The solution, however, is only a small part of all solutions obtained from anomaly-free SUSY coset models. To construct the coset models consistently, we must embed a coset coordinate in an anomaly-free spinor representation (rep) of SO(2N+2) group and give corresponding Kaehler and Killing potentials for an anomaly-free SO(2N+2)/U(N+1) model based on each positive chiral spinor rep. Using such mathematical manipulation we construct successfully the anomaly-free SO(2N+2)/U(N+1) SUSY sigma-model and investigate new aspects which have never been seen in the SUSY sigma-model on the Kaehler coset space SO(2N)/U(N). We reach a f-deformed reduced scalar potential. It is minimized with respect to the vacuum expectation value of anomaly-free SUSY sigma-model fields. Thus we find an interesting f-deformed solution very different from the previous solution for an anomaly-free SO(2.5+2)/(SU(5+1)*U(1)) SUSY sigma-model.Comment: 24 pages, no fiure

    Carbon and greenhouse gas balances in an age sequence of temperate pine plantations

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    © Author(s) 2014. This study investigated differences in the magnitude and partitioning of the carbon (C) and greenhouse gas (GHG) balances in an age sequence of four white pine (Pinus strobus L.) afforestation stands (7, 20, 35 and 70 years old as of 2009) in southern Ontario, Canada. The 4-year (2004-2008) mean annual carbon dioxide (CO2) exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes (2006-2007) and dissolved organic carbon (DOC) export below 1 m soil depth (2004-2005). The total ecosystem C pool increased with age from 46 to 197 t C ha-1 across the four stands. Rates of organic matter cycling (i.e. litterfall and decomposition) were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes, showing a peak in production and respiration rates in the middle-age (20-year-old) stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP) at the 7-year-old stand but <2% at the three older stands. The GHG balance from the combined exchanges of CO2, CH4 and N2O was 2.6, 21.6, 13.5 and 4.8 t CO2 equivalent ha-1 yearg-1 for the 7-, 20-, 35- and 70-year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4 and N2O to the GHG balance was 13 and 8% in the 7- and 70-year-old stands, respectively, but <1% in the two highly productive middle-age (20- and 35-year-old) stands. Averaged over the entire age sequence, the CO2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 t C and 297 t C ha-1 yearg-1 for stands growing on low- and high-productivity sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and GHG balances. It further demonstrates a large potential for net C sequestration and climate benefits gained through afforestation of marginal agricultural and fallow lands in temperate regions
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