1,427 research outputs found
Mammalian Stratum Corneum Contains Physiologic Lipid Thermal Transitions
Using a new high-sensitivity differential scanning calorimeter, capable of very slow scanning rates and large sample volumes, we examined the thermal transitions in neonatal mouse stratum corneum. Both physiological and supraphysiological transitions were found in intact tissue that were displaced on cooling and obliterated by solvent treatment establishing them as lipids. Physiologic peaks were encountered in lipid extracts from the same tissues. With heating and cooling recycling we found a novel effect of thermal “fractionation” of the peaks into discrete subfractions that appeared to correspond roughly the number of bands found on thin-layer chromatography of the lipid extracts
Environmental drivers of diurnal visits by transient predatory fishes to Caribbean patch reefs
Video cameras recorded the diurnal visitation rates of transient (large home range) piscivorous fishes to coral patch reefs in The Bahamas and identified 11 species. Visits by bar jack Caranx ruber, mutton snapper Lutjanus analis, yellowtail snapper Ocyurus chrysurus, barracuda Sphyraena barracuda and cero Scomberomorus regalis were sufficiently frequent to correlate with a range of biophysical factors. Patch-reef visitation rates and fish abundances varied with distance from shore and all species except S. regalis were seen more frequently inshore. This pattern is likely to be caused by factors including close proximity to additional foraging areas in mangroves and on fore-reefs and higher abundances close to inshore nursery habitats. Visitation rates and abundances of C. ruber, L. analis, O. chrysurus and S. regalis also varied seasonally (spring v. winter), possibly as fishes responded to temperature changes or undertook spawning migrations. The abundance of each transient predator species on the patch reefs generally exhibited limited diurnal variability, but L. analis was seen more frequently towards dusk. This study demonstrates that the distribution of transient predators is correlated spatially and temporally with a range of factors, even within a single lagoon, and these drivers are species specific. Transient predators are considered an important source of mortality shaping reef-fish assemblages and their abundance, in combination with the biomass of resident predators, was negatively correlated with the density of prey fishes. Furthermore, transient predators are often targeted by fishers and understanding how they utilize seascapes is critical for protecting them within reserves
Interspecific interactions among functionally diverse frugivores and their outcomes for plant reproduction: a new approach based on camera-trap data and tailored null models
Research ArticleThe study of plant-frugivore interactions is essential to understand the ecology and evolution
of many plant communities. However, very little is known about how interactions among frugivores
indirectly affect plant reproductive success. In this study, we examined direct interactions
among vertebrate frugivores sharing the same fruit resources. Then, we inferred
how the revealed direct interspecific interactions could lead to indirect (positive or negative)
effects on reproductive success of fleshy fruited plants. To do so, we developed a new analytical
approach that combines camera trap data (spatial location, visitor species, date and
time, activity) and tailored null models that allowed us to infer spatial-temporal interactions
(attraction, avoidance or indifference) between pairs of frugivore species. To illustrate our
approach, we chose to study the system composed by the Mediterranean dwarf palm, Chamaerops
humilis, the Iberian pear tree, Pyrus bourgaeana, and their shared functionally
diverse assemblages of vertebrate frugivores in a Mediterranean area of SW Spain. We first
assessed the extent to which different pairs of frugivore species tend to visit the same or different
fruiting individual plants. Then, for pairs of species that used the same individual
plants, we evaluated their spatial-temporal relationship. Our first step showed, for instance,
that some prey frugivore species (e.g. lagomorphs) tend to avoid those C. humilis individuals
that were most visited by their predators (e.g. red foxes). Also, the second step revealed
temporal attraction between large wild and domestic frugivore ungulates (e.g. red deer,
cows) and medium-sized frugivores (e.g. red foxes) suggesting that large mammals could
facilitate the C. humilis and P. bourgaeana exploitation to other smaller frugivores by making
fruits more easily accessible. Finally, our results allowed us to identify direct interaction pathways,
that revealed how the mutualistic and antagonistic relations between animal associates
derived into indirect effects on both plants seed dispersal success. For instance, we
found that large-sized seed predators (e.g. ungulates) had a direct positive effect on the likelihood
of visits by legitimate seed dispersers (e.g. red foxes) to both fleshy fruited plants.
Then, seed predators showed an indirect positive effect on the plants’ reproductive Our new analytical approach provides a widely applicable framework for further studies on
multispecies interactions in different systems beyond plant-frugivore interactions, including
plant-pollinator interactions, the exploitation of plants by herbivores, and the use of carcasses
by vertebrate scavengersinfo:eu-repo/semantics/publishedVersio
Calorimetric and Electron Spin Resonance Examination of Lipid Phase Transitions in Human Stratum Corneum: Molecular Basis for Normal Cohesion and Abnormal Desquamation in Recessive X-Linke Ichthyosis
Lipids appear to play a critical role as regulators of stratum corneum desquamation. In this study, we observed discrete lipid phase transitions at physiologic temperatures in both normal human scale (NHS) and in lipid extracts of NHS by differential scanning calorimetry. In contrast, such thermal transitions were not observed in recessive x-linked ichthyosis scale (RXLIS). To gain further insight into the molecular basis of the lipid phase transitions in NHS vs. RXLIS, comparable samples were evaluated by electron spin resonance, utilizing the perdeuterated probe, di-t-butyl nitroxide. Upon electron spin resonance analysis, both NHS and RXLIS demonstrated thermal phase transitions in the physiologic range; however, the nature of the lipid environments in each type varied. Whereas the environment of the spin probe was more polar in NHS than in RXLIS, the spin probe partitioned into a more “fluid” environment in RXLIS; i.e., the spin probe was more mobile in RXLIS titan in NHS lipid matrices. Because an alteration in the cholesteryl sulfate : cholesterol ratio is the primary lipid abnormality in RXLIS, model cholesterol-fatty acid-cholesteryl sulfate mixtures were prepared in proportion to the lipid composition of NHS and RXLIS. Differences were observed in both thermal transitions and in lipid microenvironments in these mixtures that paralleled those observed in scale samples. Based on these results, a model is proposed that invokes abnormal hydrogen bonding, due to increased cholesteryl sulfate, as the mechanism for the abnormal desquamation in recessive X-linked ichthyosis
But a walking shadow: designing, performing and learning on the virtual stage
Representing elements of reality within a medium, or taking aspects from one medium and placing them in another is an act of remediation. The process of this act, however, is largely taken for granted. Despite the fact that available information enables a qualitative assessment of the history of multimedia and their influences on different fields of knowledge, there are still some areas that require more focused research attention. For example, the relationship between media evolution and new developments in scenographic practice is currently under investigation. This article explores the issue of immediacy as a condition of modern theatre in the context of digital reality. It discusses the opportunities and challenges that recent technologies present to contemporary practitioners and theatre design educators, creating a lot of scope to break with conventions. Here, we present two case studies that look into technology-mediated learning about scenography through the employment of novel computer visualization techniques. The first case study is concerned with new ways of researching and learning about theatre through creative exploration of design artefacts. The second case study investigates the role of the Immersive Virtual World Second Life™ (SL) in effective teaching of scenography, and in creating and experiencing theatrical performances
Quantum Delocalized Interactions
Classical mechanics obeys the intuitive logic that a physical event happens at a definite spatial point. Entanglement, however, breaks this logic by enabling interactions without a specific location. In this work we study these delocalized interactions. These are quantum interactions that create less locational information than would be possible classically, as captured by the disturbance induced on some spatial superposition state. We introduce quantum games to capture the effect and demonstrate a direct operational use for quantum concurrence in that it bounds the nonclassical performance gain. We also find a connection with quantum teleportation, and demonstrate the games using an IBM quantum processor
Gene Therapy with Endogenous Inhibitors of Angiogenesis for Neovascular Age-Related Macular Degeneration: Beyond Anti-VEGF Therapy
Age-related macular degeneration (AMD) is the leading cause of substantial and irreversible vision loss amongst elderly populations in industrialized countries. The advanced neovascular (or “wet”) form of the disease is responsible for severe and aggressive loss of central vision. Current treatments aim to seal off leaky blood vessels via laser therapy or to suppress vessel leakage and neovascular growth through intraocular injections of antibodies that target vascular endothelial growth factor (VEGF). However, the long-term success of anti-VEGF therapy can be hampered by limitations such as low or variable efficacy, high frequency of administration (usually monthly), potentially serious side effects, and, most importantly, loss of efficacy with prolonged treatment. Gene transfer of endogenous antiangiogenic proteins is an alternative approach that has the potential to provide long-term suppression of neovascularization and/or excessive vascular leakage in the eye. Preclinical studies of gene transfer in a large animal model have provided impressive preliminary results with a number of transgenes. In addition, a clinical trial in patients suffering from advanced neovascular AMD has provided proof-of-concept for successful gene transfer. In this mini review, we summarize current theories pertaining to the application of gene therapy for neovascular AMD and the potential benefits when used in conjunction with endogenous antiangiogenic proteins
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Contamination and uniformity control in plasma processing tools
This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). We have collaborated with industry to build a laboratory to study plasma processing, a surface-cleaning technique that uses short-lived, gaseous reactants in place of chemical solvents. We have performed experiments and developed computer models to understand how complex substrate geometries affect plasma electrical properties and to demonstrate the feasibility of generating metastable molecular oxygen in a plasma
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