895 research outputs found

    Integrated Flush Air Data Sensing System Modeling for Planetary Entry Guidance with Direct Force Control

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    Flush air data sensing (FADS) systems have been previously used at both Earth and Mars to provide onboard estimates of angle of attack, sideslip angle, and dynamic pressure. However, these FADS data were often not used in an in-the-loop sense to inform the onboard guidance and control systems. A method to integrate FADS-derived density and wind estimates with a numerical predictor-corrector guidance algorithm is presented. The method is demonstrated in a high-fidelity simulation of a human-scale Mars entry vehicle that utilizes a hypersonic inflatable aerodynamic decelerator (HIAD) with direct force control. Effects on guidance commands and state uncertainties both with and without FADS system modeling are presented and discussed

    Adsorption of Toxic Metal Ions From Solution by Inactivated Cells of Larrea Tridentata Creosote Bush

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    Larrea tridentata (creosote bush) is a plant that grows abundantly in the desert environment. This desert plant has been found naturally growing in heavy-metal contaminated soils. Previous experiments showed that the inactivated biomass of creosote bush was able to adsorb Cu(II) ions from aqueous solutions. The copper-binding capacity of the bush biomass that grows in heavy-metal uncontaminated soils was higher than the biomass that grows in heavy-metal contaminated soils. Experiments were performed to determine the ability of creosote bush biomass (grown in heavy metal uncontaminated soils) to adsorb Pb(II), Cd(II), Zn(II), Cr(III), Cr(VI), and Ni(II) ions from aqueous solutions. Batch pH profile experiments for these metal ions showed that the metal ion binding was different for every metal tested but increased as the pH was raised from 2.0 to 6.0. The metal ion uptake by the roots, stems, and leaves was quite fast. Binding capacity experiments showed a more significant binding capacity for lead(II) and chromium(III) ions and in general, the leaves bound more metal ions than the stems and roots. A great portion of the metal ions adsorbed by the creosote’s roots, stems, and leaves was desorbed by treatment with 0.1 M HCl (up to 99% in some cases). Biomass of creosote bush may prove to be useful to remove and recover metal ions from contaminated waters

    Sketch-To-Solution: An Exploration of Viscous CFD with Automatic Grids

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    Numerical simulation of the Reynolds-averaged NavierStokes (RANS) equations has become a critical tool for the design of aerospace vehicles. However, the issues that affect the grid convergence of three dimensional RANS solutions are not completely understood, as documented in the AIAA Drag Prediction Workshop series. Grid adaption methods have the potential for increasing the automation and discretization error control of RANS solutions to impact the aerospace design and certification process. The realization of the CFD Vision 2030 Study includes automated management of errors and uncertainties of physics-based, predictive modeling that can set the stage for ensuring a vehicle is in compliance with a regulation or specification by using analysis without demonstration in flight test (i.e., certification or qualification by analysis). For example, the Cart3D inviscid analysis package has automated Cartesian cut-cell gridding with output-based error control. Fueled by recent advances in the fields of anisotropic grid adaptation, error estimation, and geometry modeling, a similar work flow is explored for viscous CFD simulations; where a CFD application engineer provides geometry, boundary conditions, and flow parameters, and the sketch-to-solution process yields a CFD simulation through automatic, error-based, grid adaptation

    Discovery of Unique Lanthionine Synthetases Reveals New Mechanistic and Evolutionary Insights

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    Identification of a new class of lanthionine synthetases provides insight into the mechanism and evolution of cyclic peptide biosynthesis

    Ribosomally synthesized and post-translationally modified peptide natural products: overview and recommendations for a universal nomenclature

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    This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the \u3e20 distinct compound classes is also reviewed, and commonalities are discussed

    Traditional and Health-Related Philanthropy: The Role of Resources and Personality

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    I study the relationships of resources and personality characteristics to charitable giving, postmortem organ donation, and blood donation in a nationwide sample of persons in households in the Netherlands. I find that specific personality characteristics are related to specific types of giving: agreeableness to blood donation, empathic concern to charitable giving, and prosocial value orientation to postmortem organ donation. I find that giving has a consistently stronger relation to human and social capital than to personality. Human capital increases giving; social capital increases giving only when it is approved by others. Effects of prosocial personality characteristics decline at higher levels of these characteristics. Effects of empathic concern, helpfulness, and social value orientations on generosity are mediated by verbal proficiency and church attendance.

    Heterologous expression of a cryptic gene cluster from Streptomyces leeuwenhoekii C34T yields a novel lasso peptide, leepeptin

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    ACKNOWLEDGEMENTS. We are grateful to Michael Goodfellow and Alan Bull for providing S. leeuwenhoekii C34T , and to Michael Fischbach and Jan Claesen for S. viridochromogenes and S. pristinaspiralis, Matthias Mach for S. davawensis, and Kristian Apel on October 31, 2019 at University of Aberdeen http://aem.asm.org/ Downloaded from 17 for S. roseochromogenes. We thank Govind Chandra for advice on blastP analyses of the lasso peptide data sets, Solène Rollet for technical support in the isolation of leepeptin and Andrew Truman for his comments on the manuscript. J.F.C. and V.R. received National PhD Scholarships (#21110356 and #21110384, respectively) and Visiting Student Scholarships (Becas Chile, 2013–2014) from the National Commission for Scientific and Technological Research (CONICYT). S.A.J. thanks the University of Aberdeen for an Elphinstone Scholarship. This work was supported financially by the Biotechnological and Biological Sciences Research Council (BBSRC, United Kingdom) Institute Strategic Programme Grant “Understanding and Exploiting Plant and Microbial Secondary Metabolism” (BB/J004561/1), the Basal Programme of CONICYT (Chile) for funding of the Centre for Biotechnology and Bioengineering, CeBiB (project FB0001) and the UK Newton Project for UK–Chile collaboration (grant JIC CA586).Peer reviewedPublisher PD

    Development of combi-pills using the coupling of semi-solid syringe extrusion 3D printing with fused deposition modelling

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    Data availability: Data will be made available on request.Copyright © 2022 The Authors. Three-dimensional (3D) printing allows for the design and printing of more complex designs than traditional manufacturing processes. For the manufacture of personalised medicines, such an advantage could enable the production of personalised drug products on demand. In this study, two types of extrusion-based 3D printing techniques, semi-solid syringe extrusion 3D printing and fused deposition modelling, were used to fabricate a combi-layer construct (combi-pill). Two model drugs, tranexamic acid (water soluble, rapid release) and indomethacin (poorly water-soluble, extended release), were printed with different geometries and materials compositions. Fourier transform infrared spectroscopy results showed that there were no interactions detected between drug-drug and drug-polymers. The printed combi-pills demonstrated excellent abrasion resisting properties in friability tests. The use of different functional excipients demonstrated significant impact on in vitro drug release of the model drugs incorporated in two 3D printed layers. Tranexamic acid and indomethacin were successfully 3D printed as a combi-pill with immediate-release and sustained-release profiles, respectively, to target quick anti-bleeding and prolonged anti-inflammation functions. For the first time, this paper systematically demonstrates the feasibility of coupling syringe-based extrusion 3D printing and fused deposition modelling as an innovative platform for various drug therapy productions, facilitating a new era of personalised combi-pills development.Redistributed Manufacturing in Healthcare Network (RiHN). The RiHN was awarded a grant from the UK Engineering and Physical Sciences Research Council (EPSRC) (Ref. EP/T014970/1)

    Synthetic RNA Silencing of Actinorhodin Biosynthesis in Streptomyces coelicolor A3(2)

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    We demonstrate the first application of synthetic RNA gene silencers in Streptomyces coelicolor A3(2). Peptide nucleic acid and expressed antisense RNA silencers successfully inhibited actinorhodin production. Synthetic RNA silencing was target-specific and is a new tool for gene regulation and metabolic engineering studies in Streptomyces.Peer reviewe
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