176 research outputs found

    Algal biomass and diesel emulsions: An alternative approach for utilizing the energy content of microalgal biomass in diesel engines

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    The use of algal biomass for the production of sustainable biofuels has attracted significant interest due to the fast reproduction rates and high lipid content of many microalgal species. However, existing methods of extracting algal cellular lipids are complex and expensive, with regards to both energy input and economic costs. This work explores an alternative method of utilizing the energy content of microalgae through the preparation of wet algal biomass slurry/fossil diesel emulsions containing up to 6.6% wt/wt algae biomass, using a specific surfactant combination, for direct injection diesel engine combustion of microalgae without prior biomass drying or lipid extraction. A high lipid containing green microalgae, Chlorella sorokiniana, was used to produce algal biomass for the study. The preparation of wet algal slurry/diesel emulsions from algae grown under standard conditions, and also those under conditions intended to increase cellular lipid content or growth rates was investigated, and in all cases a surfactant pack of Span80, CTAB and butanol was found to produce a stable emulsion. A correlation between the engine work produced during combustion of the emulsions in a modern direct injection compression ignition and the lower heating value of the wet slurry emulsions was found, with no evidence of individual algae cells persisting to the engine exhaust. Engine exhaust emissions of nitrogen oxides (NOx) and particulate matter were lower for all of the wet algal slurry/diesel emulsions relative to a reference fossil diesel tested under similar conditions, while in the case of the emulsion prepared from algal biomass to which a flocculating agent had been added, emissions of carbon monoxide (CO) were found to increase significantly

    Cannabidiol Reduces Intestinal Inflammation through the Control of Neuroimmune Axis

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    Enteric glial cells (EGC) actively mediate acute and chronic inflammation in the gut; EGC proliferate and release neurotrophins, growth factors, and pro-inflammatory cytokines which, in turn, may amplify the immune response, representing a very important link between the nervous and immune systems in the intestine. Cannabidiol (CBD) is an interesting compound because of its ability to control reactive gliosis in the CNS, without any unwanted psychotropic effects. Therefore the rationale of our study was to investigate the effect of CBD on intestinal biopsies from patients with ulcerative colitis (UC) and from intestinal segments of mice with LPS-induced intestinal inflammation. CBD markedly counteracted reactive enteric gliosis in LPS-mice trough the massive reduction of astroglial signalling neurotrophin S100B. Histological, biochemical and immunohistochemical data demonstrated that S100B decrease was associated with a considerable decrease in mast cell and macrophages in the intestine of LPS-treated mice after CBD treatment. Moreover the treatment of LPS-mice with CBD reduced TNF-α expression and the presence of cleaved caspase-3. Similar results were obtained in ex vivo cultured human derived colonic biopsies. In biopsies of UC patients, both during active inflammation and in remission stimulated with LPS+INF-γ, an increased glial cell activation and intestinal damage were evidenced. CBD reduced the expression of S100B and iNOS proteins in the human biopsies confirming its well documented effect in septic mice. The activity of CBD is, at least partly, mediated via the selective PPAR-gamma receptor pathway. CBD targets enteric reactive gliosis, counteracts the inflammatory environment induced by LPS in mice and in human colonic cultures derived from UC patients. These actions lead to a reduction of intestinal damage mediated by PPARgamma receptor pathway. Our results therefore indicate that CBD indeed unravels a new therapeutic strategy to treat inflammatory bowel diseases

    Endogenous Zinc in Neurological Diseases

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    The use of zinc in medicinal skin cream was mentioned in Egyptian papyri from 2000 BC (for example, the Smith Papyrus), and zinc has apparently been used fairly steadily throughout Roman and modern times (for example, as the American lotion named for its zinc ore, 'Calamine'). It is, therefore, somewhat ironic that zinc is a relatively late addition to the pantheon of signal ions in biology and medicine. However, the number of biological functions, health implications and pharmacological targets that are emerging for zinc indicate that it might turn out to be 'the calcium of the twenty-first century'. Here neurobiological roles of endogenous zinc is summarized

    CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

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    CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, rr, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r>0.003r > 0.003 at greater than 5σ5\sigma, or, in the absence of a detection, of reaching an upper limit of r<0.001r < 0.001 at 95%95\% CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note: text overlap with arXiv:1907.0447
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