5,448 research outputs found

    The ecology, biogeography, history and future of two globally important weeds : Cardiospermum halicacabum Linn. and C. grandiflorum Sw.

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    Members of the balloon vine genus, Cardiospermum, have been extensively moved around the globe as medicinal and horticultural species, two of which are now widespread invasive species; C. grandiflorum and C. halicacabum. A third species, C. corindum, may also have significant invasion potential. However, in some regions the native status of these species is not clear, hampering management. For example, in South Africa it is unknown whether C. halicacabum and C. corindum are native, and this is a major constraint to on-going biological control programmes against invasive C. grandiflorum. We review the geography, biology and ecology of selected members of the genus with an emphasis on the two most widespread invaders, C. halicacabum and C. grandiflorum. Specifically, we use molecular data to reconstruct a phylogeny of the group in order to shed light on the native ranges of C. halicacabum and C. corindum in southern Africa. Phylogenetic analyses indicate that southern African accessions of these species are closely related to South American taxa indicating human-mediated introduction and/or natural long distance dispersal. Then, on a global scale we use species distribution modelling to predict potential suitable climate regions where these species are currently absent. Native range data were used to test the accuracy with which bioclimatic modelling can identify the known invasive ranges of these species. Results show that Cardiospermum species have potential to spread further in already invaded or introduced regions in Australia, Africa and Asia, underlining the importance of resolving taxonomic uncertainties for future management efforts. Bioclimatic modelling predicts Australia to have highly favourable environmental conditions for C. corindum and therefore vigilance against this species should be high. Species distribution modelling showed that native range data over fit predicted suitable ranges, and that factors other than climate influence establishment potential. This review opens the door to better understand the global biogeography of the genus Cardiospermum, with direct implications for management, while also highlighting gaps in current research

    Prospective life cycle assessment of a bioprocess design for cultured meat production in hollow fiber bioreactors

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    The aim of cellular agriculture is to use cell-culturing technologies to produce alternatives to agricultural products. Cul-tured meat is an example of a cellular agriculture product, made by using tissue engineering methods. This study aims to improve the understanding of the potential environmental impacts of cultured meat production by comparing be-tween different bioprocess design scenarios. This was done by carrying out a life cycle assessment (LCA) for a bioprocess system using hollow fiber bioreactors, and utilizing bench-scale experimental data for C2C12 cell prolifer-ation, differentiation and media metabolism. Scenario and sensitivity analyses were used to test the impact of changes in the system design, data sources, and LCA methods on the results to support process design decision making. We com-pared alternative scenarios to a baseline of C2C12 cells cultured in hollow fiber bioreactors using media consisting of DMEM with serum, for a 16-day proliferation stage and 7-day differentiation stage. The baseline LCA used the average UK electricity mix as the energy source, and heat treatment for wastewater sterilization. The greatest reduction in en-vironmental impacts were achieved with the scenarios using CHO cell metabolism instead of C2C12 cell metabolisim (64-67 % reduction); achieving 128 % cell biomass increase during differentiation instead of no increase (42-56 % reduction); using wind electricity instead of average UK electricity (6-39 % reduction); and adjusting the amino acid use based on experimental data (16-27 % reduction). The use of chemical wastewater treatment instead of heat treatment increased all environmental impacts, except energy demand, by 1-16 %. This study provides valuable insights for the cultured meat field to understand the effects of different process design scenarios on environmental impacts, and therefore provides a framework for deciding where to focus development efforts for improving the envi-ronmental performance of the production system.Peer reviewe

    Hollow-fiber membrane technology: Characterization and proposed use as a potential mimic of skin vascularization towards the development of a novel skin absorption in vitro model

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    Dermal bioavailability is currently estimated through skin penetration studies using ex vivo models, which lack any measure of capillary bed function, and thus do not fully reproduce physiological conditions. We propose a novel strategy to mimic skin vascularization using newly fabricated hollow fibers made from a biocompatible membrane material, polystyrene, which is hydrophobic if left untreated, or hydrophilic when its surface polarity is modified through plasma-treatment. Caffeine has been well studied in skin penetration assays and was used here to determine the permeation properties of the hollow fibers in a novel jacketed glass bioreactor. For hydrophobic fibers, approximately 87.2 % of the caffeine dose did not penetrate the porous surface; 0.2 % of the dose was collected after 24 h (permeated through the pores), and therefore 12.6 % of the initial dose was suspected to block the membrane. For hydrophilic fibers, both the percentage of the initial dose that permeated and that of blocking caffeine increased to 1.2 % and 35.2 % respectively. It was concluded that caffeine permeated the hollow fibers at similar times of clearance to those observed in vivo, and therefore shows that this new model could provide a surrogate for capillary-based clearance in in vitro skin absorption studies

    Higgs Decay to Two Photons

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    The amplitude for Higgs decay to two photons is calculated in renormalizable and unitary gauges using dimensional regularization at intermediate steps. The result is finite, gauge independent, and in agreement with previously published results. The large Higgs mass limit is examined using the Goldstone-boson equivalence theorem as a check on the use of dimensional regularization and to explain the absence of decoupling.Comment: 15 pages, 5 figures; references adde

    Colorado Native Plant Society Newsletter, Vol. 5 No. 4, October-December 1981

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    https://epublications.regis.edu/aquilegia/1159/thumbnail.jp

    Future asymptotic expansions of Bianchi VIII vacuum metrics

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    Bianchi VIII vacuum solutions to Einstein's equations are causally geodesically complete to the future, given an appropriate time orientation, and the objective of this article is to analyze the asymptotic behaviour of solutions in this time direction. For the Bianchi class A spacetimes, there is a formulation of the field equations that was presented in an article by Wainwright and Hsu, and in a previous article we analyzed the asymptotic behaviour of solutions in these variables. One objective of this paper is to give an asymptotic expansion for the metric. Furthermore, we relate this expansion to the topology of the compactified spatial hypersurfaces of homogeneity. The compactified spatial hypersurfaces have the topology of Seifert fibred spaces and we prove that in the case of NUT Bianchi VIII spacetimes, the length of a circle fibre converges to a positive constant but that in the case of general Bianchi VIII solutions, the length tends to infinity at a rate we determine.Comment: 50 pages, no figures. Erronous definition of Seifert fibred spaces correcte

    Fibroblast growth factors 1 and 2 in cerebrospinal fluid are associated with HIV disease, methamphetamine use, and neurocognitive functioning.

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    BackgroundHuman immunodeficiency virus (HIV) and methamphetamine use commonly affect neurocognitive (NC) functioning. We evaluated the relationships between NC functioning and two fibroblast growth factors (FGFs) in volunteers who differed in HIV serostatus and methamphetamine dependence (MAD).MethodsA total of 100 volunteers were categorized into four groups based on HIV serostatus and MAD in the prior year. FGF-1 and FGF-2 were measured in cerebrospinal fluid by enzyme-linked immunosorbent assays along with two reference biomarkers (monocyte chemotactic protein [MCP]-1 and neopterin). Comprehensive NC testing was summarized by global and domain impairment ratings.ResultsSixty-three volunteers were HIV+ and 59 had a history of MAD. FGF-1, FGF-2, and both reference biomarkers differed by HIV and MAD status. For example, FGF-1 levels were lower in subjects who had either HIV or MAD than in HIV- and MAD- controls (P=0.003). Multivariable regression identified that global NC impairment was associated with an interaction between FGF-1 and FGF-2 (model R(2)=0.09, P=0.01): higher FGF-2 levels were only associated with neurocognitive impairment among subjects who had lower FGF-1 levels. Including other covariates in the model (including antidepressant use) strengthened the model (model R(2)=0.18, P=0.004) but did not weaken the association with FGF-1 and FGF-2. Lower FGF-1 levels were associated with impairment in five of seven cognitive domains, more than FGF-2, MCP-1, or neopterin.ConclusionThese findings provide in vivo support that HIV and MAD alter expression of FGFs, which may contribute to the NC abnormalities associated with these conditions. These cross-sectional findings cannot establish causality and the therapeutic benefits of recombinant FGF-1 need to be investigated

    A high specific strength, deformation-processed scandium-titanium composite

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    A 59% Sc–41% Ti deformation-processed metal-metal composite was produced by rolling to a true strain of 2.3 at 873 K followed by cold rolling to a total true strain of 3.6. Rolling reduced the original eutectoid microstructure to lamellae of α–Sc and α–Ti with average lamellar thicknesses of 150 nm (Sc) and 120 nm (Ti). The cold-rolled material had an ultimate tensile strength of 942 MPa and a specific strength of 259 J/g. The Sc matrix was oriented with the 〈0001〉 tilted 22° from the sheet normal direction toward the rolling direction, an unusual texture for an HCP metal with a low c/a ratio, which suggests Sc may deform primarily by basal slip
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