332 research outputs found

    Characterisation of a Desmosterol Reductase Involved in Phytosterol Dealkylation in the Silkworm, Bombyx mori

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    Most species of invertebrate animals cannot synthesise sterols de novo and many that feed on plants dealkylate phytosterols (mostly C29 and C28) yielding cholesterol (C27). The final step of this dealkylation pathway involves desmosterol reductase (DHCR24)-catalysed reduction of desmosterol to cholesterol. We now report the molecular characterisation in the silkworm, Bombyx mori, of such a desmosterol reductase involved in production of cholesterol from phytosterol, rather than in de novo synthesis of cholesterol. Phylogenomic analysis of putative desmosterol reductases revealed the occurrence of various clades that allowed for the identification of a strong reductase candidate gene in Bombyx mori (BGIBMGA 005735). Following PCR-based cloning of the cDNA (1.6 kb) and its heterologous expression in Saccharomyces cerevisae, the recombinant protein catalysed reduction of desmosterol to cholesterol in an NADH- and FAD- dependent reaction

    Climate and southern Africa's water-energy-food nexus

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    In southern Africa, the connections between climate and the water-energy-food nexus are strong. Physical and socioeconomic exposure to climate is high in many areas and in crucial economic sectors. Spatial interdependence is also high, driven for example, by the regional extent of many climate anomalies and river basins and aquifers that span national boundaries. There is now strong evidence of the effects of individual climate anomalies, but associations between national rainfall and Gross Domestic Product and crop production remain relatively weak. The majority of climate models project decreases in annual precipitation for southern Africa, typically by as much as 20% by the 2080s. Impact models suggest these changes would propagate into reduced water availability and crop yields. Recognition of spatial and sectoral interdependencies should inform policies, institutions and investments for enhancing water, energy and food security. Three key political and economic instruments could be strengthened for this purpose; the Southern African Development Community, the Southern African Power Pool, and trade of agricultural products amounting to significant transfers of embedded water

    Notions of Well-Being, the State of Child Well-Being Research and the MYWEB Project

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    There has been a growing interest among academics, policy makers and practitioners in the subjective well-being of children and young people (CYP). The recognition of CYP’s rights to having a good childhood and good future life chances, coupled with the injunction from the New Sociology of Childhood to consult with CYP as active agents have resulted in an increasing number of studies on children and young people’s well-being at national and international levels. However, the design, content, and modes of data collection used in these surveys are influenced by the question of the extent to which the researchers view children and young people as similar or different to adults and which participatory models they are undertaking for the young people in the study. However, the design, content, and modes of data collection used in these surveys are influenced by a number of factors including conceptual underpinning of well-being, its measurement and participatory model(s) used by the researchers for children in those surveys. This chapter reviews these aspects before describing the structure of this book with summaries of each subsequent chapter

    New insight into kinetics behavor of the structural formation process in Agar gelation

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    A time-resolved experimental study on the kinetics and relaxation of the structural formation process in gelling Agar-water solutions was carried out using our custom-built torsion resonator. The study was based on measurements of three naturally cooled solutions with agar concentrations of 0.75%, 1.0% and 2.0% w/w. It was found that the natural-cooling agar gelation process could be divided into three stages, sol stage (Stage I), gelation zone (Stage II) and gel stage (Stage III), based on the time/temperature evolutions of the structural development rate (SDR). An interesting fluctuant decaying behavior of SDR was observed in Stage II and III, indicative of a sum of multiple relaxation processes and well described by a multiple-order Gaussisn-like equation: . More interestingly, the temperature dependences of the fitted values of Wn in Stage II and Stage III were found to follow the different Arrhenius laws, with different activation energies of EaII= 39-74 KJ/mol and EaIII~7.0 KJ/mol. The two different Arrhenius-like behaviors respectively suggest that dispersions in Stage II be attributed to the relaxation of the self-assembly of agar molecules or the growth of junction zones en route to gelation, in which the formation or fission of hydrogen bonding interactions plays an important role; and that dispersions in Stage III be attributed to the relaxation dynamics of water released from various size domains close to the domain of the viscous flow of water during the syneresis process.Comment: 24 pages, 4 figures, 1 tabl

    Crown Plasticity and Competition for Canopy Space: A New Spatially Implicit Model Parameterized for 250 North American Tree Species

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    BACKGROUND: Canopy structure, which can be defined as the sum of the sizes, shapes and relative placements of the tree crowns in a forest stand, is central to all aspects of forest ecology. But there is no accepted method for deriving canopy structure from the sizes, species and biomechanical properties of the individual trees in a stand. Any such method must capture the fact that trees are highly plastic in their growth, forming tessellating crown shapes that fill all or most of the canopy space. METHODOLOGY/PRINCIPAL FINDINGS: We introduce a new, simple and rapidly-implemented model--the Ideal Tree Distribution, ITD--with tree form (height allometry and crown shape), growth plasticity, and space-filling, at its core. The ITD predicts the canopy status (in or out of canopy), crown depth, and total and exposed crown area of the trees in a stand, given their species, sizes and potential crown shapes. We use maximum likelihood methods, in conjunction with data from over 100,000 trees taken from forests across the coterminous US, to estimate ITD model parameters for 250 North American tree species. With only two free parameters per species--one aggregate parameter to describe crown shape, and one parameter to set the so-called depth bias--the model captures between-species patterns in average canopy status, crown radius, and crown depth, and within-species means of these metrics vs stem diameter. The model also predicts much of the variation in these metrics for a tree of a given species and size, resulting solely from deterministic responses to variation in stand structure. CONCLUSIONS/SIGNIFICANCE: This new model, with parameters for US tree species, opens up new possibilities for understanding and modeling forest dynamics at local and regional scales, and may provide a new way to interpret remote sensing data of forest canopies, including LIDAR and aerial photography

    What is behind smoker support for new smokefree areas? National survey data

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    BACKGROUND: Some countries have started to extend indoor smokefree laws to cover cars and various outdoor settings. However, policy-modifiable factors around smoker support for these new laws are not well described. METHODS: The New Zealand (NZ) arm of the International Tobacco Control Policy Evaluation Survey (ITC Project) derives its sample from the NZ Health Survey (a national sample). From this sample we surveyed adult smokers (n = 1376). RESULTS: For the six settings considered, 59% of smokers supported at least three new completely smokefree areas. Only 2% favoured smoking being allowed in all the six new settings. Support among Maori, Pacific and Asian smokers relative to European smokers was elevated in multivariate analyses, but confidence intervals often included 1.0.Also in the multivariate analyses, "strong support" by smokers for new smokefree area laws was associated with greater knowledge of the second-hand smoke (SHS) hazard, and with behaviours to reduce SHS exposure towards others. Strong support was also associated with reporting having smokefree cars (aOR = 1.68, 95% CI = 1.21 - 2.34); and support for tobacco control regulatory measures by government (aOR = 1.63, 95% CI = 1.32 - 2.01). There was also stronger support by smokers with a form of financial stress (not spending on household essentials). CONCLUSIONS: Smokers from a range of population groups can show majority support for new outdoor and smokefree car laws. Some of these findings are consistent with the use of public health strategies to support new smokefree laws, such as enhancing public knowledge of the second-hand smoke hazard

    Medical Therapies for Uterine Fibroids - A Systematic Review and Network Meta-Analysis of Randomised Controlled Trials

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    BACKGROUND: Uterine fibroids are common, often symptomatic and a third of women need repeated time off work. Consequently 25% to 50% of women with fibroids receive surgical treatment, namely myomectomy or hysterectomy. Hysterectomy is the definitive treatment as fibroids are hormone dependent and frequently recurrent. Medical treatment aims to control symptoms in order to replace or delay surgery. This may improve the outcome of surgery and prevent recurrence. PURPOSE: To determine whether any medical treatment can be recommended in the treatment of women with fibroids about to undergo surgery and in those for whom surgery is not planned based on currently available evidence. STUDY SELECTION: Two authors independently identified randomised controlled trials (RCT) of all pharmacological treatments aimed at the treatment of fibroids from a list of references obtained by formal search of MEDLINE, EMBASE, Cochrane library, Science Citation Index, and ClinicalTrials.gov until December 2013. DATA EXTRACTION: Two authors independently extracted data from identified studies. DATA SYNTHESIS: A Bayesian network meta-analysis was performed following the National Institute for Health and Care Excellence-Decision Support Unit guidelines. Odds ratios, rate ratios, or mean differences with 95% credible intervals (CrI) were calculated. RESULTS AND LIMITATIONS: A total of 75 RCT met the inclusion criteria, 47 of which were included in the network meta-analysis. The overall quality of evidence was very low. The network meta-analysis showed differing results for different outcomes. CONCLUSIONS: There is currently insufficient evidence to recommend any medical treatment in the management of fibroids. Certain treatments have future promise however further, well designed RCTs are needed

    Multiscale multifactorial approaches for engineering tendon substitutes

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    The physiology of tendons and the continuous strains experienced daily make tendons very prone to injury. Excessive and prolonged loading forces and aging also contribute to the onset and progression of tendon injuries, and conventional treatments have limited efficacy in restoring tendon biomechanics. Tissue engineering and regenerative medicine (TERM) approaches hold the promise to provide therapeutic solutions for injured or damaged tendons despite the challenging cues of tendon niche and the lack of tendon-specific factors to guide cellular responses and tackle regeneration. The roots of engineering tendon substitutes lay in multifactorial approaches from adequate stem cells sources and environmental stimuli to the construction of multiscale 3D scaffolding systems. To achieve such advanced tendon substitutes, incremental strategies have been pursued to more closely recreate the native tendon requirements providing structural as well as physical and chemical cues combined with biochemical and mechanical stimuli to instruct cell behavior in 3D architectures, pursuing mechanically competent constructs with adequate maturation before implantation.Authors acknowledge the project “Accelerating tissue engineering and personalized medicine discoveries by the integration of key enabling nanotechnologies, marinederived biomaterials and stem cells,” supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Authors acknowledge the H2020 Achilles Twinning Project No. 810850, and also the European Research Council CoG MagTendon No. 772817, and the FCT Project MagTT PTDC/CTM-CTM/ 29930/2017 (POCI-01-0145-FEDER-29930

    Assessment of acute myocardial infarction: current status and recommendations from the North American society for cardiovascular imaging and the European society of cardiac radiology

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    There are a number of imaging tests that are used in the setting of acute myocardial infarction and acute coronary syndrome. Each has their strengths and limitations. Experts from the European Society of Cardiac Radiology and the North American Society for Cardiovascular Imaging together with other prominent imagers reviewed the literature. It is clear that there is a definite role for imaging in these patients. While comparative accuracy, convenience and cost have largely guided test decisions in the past, the introduction of newer tests is being held to a higher standard which compares patient outcomes. Multicenter randomized comparative effectiveness trials with outcome measures are required
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