47 research outputs found

    A predictive model for failure properties of thermoset resins

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    A predictive model for the three-dimensional failure behavior of engineering polymers has been developed in a recent NASA-sponsored research program. This model acknowledges the underlying molecular deformation mechanisms and thus accounts for the effects of different chemical compositions, crosslink density, functionality of the curing agent, etc., on the complete nonlinear stress-strain response including yield. The material parameters required by the model can be determined from test-tube quantities of a new resin in only a few days. Thus, we can obtain a first-order prediction of the applicability of a new resin for an advanced aerospace application without synthesizing the large quantities of material needed for failure testing. This technology will effect order-of-magnitude reductions in the time and expense required to develop new engineering polymers

    A language and compiler for enabling automatic and parallel chemistry simulations

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    The modeling of chemical reactions, and the ability to predict the properties of the end- products of a chemical reaction, is of extreme commercial importance. The properties of many compounds have complex dependencies on a variety of additives, in ways that are not well understood. This paper describes a domain specific language, compiler and parallel runtime system that allows chemists to investigate, and understand how, different additives affect these properties. In particular, our system allows the inputs and types of reactions that are possible to be specified in a high level language. It then produces a set of ordinary differential equations (ODEs) that when combined with boundary conditions from quantum chemistry are processed using parallel templates and off-the-shelf solvers to simulate the reaction. This paper describes the complete system, including optimizations to reduce the amount of redundant computation in the ODEs, the parallel templates for simulating the reaction, and experimental data showing the effectiveness of these. Our system saves the chemist from manually developing, testing and debugging systems of hundreds or thousands of ODEs that require weeks or months to develop

    Analysis of Chlamydia pneumoniae-infected monocytes following incubation with a novel peptide, acALY18, implicates the inflammasome in clearance of infection

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    Chlamydia pneumoniae infection may be a trigger for the pathology observed in sporadic lateonset Alzheimer’s disease as a function of initiating neuroinflammation following entry of the organism into the brain. We have hypothesized that one entry mechanism may be by bloodborne infected monocytes trafficking the infection into the brain. This study focuses on infection of monocytes in vitro followed by analysis using immunofluorescence labeling and RT-PCR-microarray techniques. The microarrays utilized consisted of an Alzheimer’s disease pathway array and an innate and adaptive immunity array from SAbiosciences. Analysis by real time PCR for both gene arrays was performed on uninfected and C. pneumoniae-infected THP1 monocytes at 48 hr post-infection. In addition, we analyzed innate and adaptive immunity gene regulation changes following treatment of infected cells with a unique peptide, acALY18, derived from the endogenously expressed endoplasmic reticulum protein TRPC1. The peptide appears to stimulate the innate immune system through activation of the inflammasome. C. pneumoniae prominently infected THP1 monocytes at 24-48hr. Numerous large inclusions were identified using specific chlamydial monoclonal antibodies. Monocyte gene expression changes induced by infection with C. pneumoniae revealed significant up-regulation of 45 genes in the Alzheimer’s disease pathway. These included genes involved in: b-amyloid processing and clearance, apoptosis, proteases and protein kinases, and lipid metabolism. In contrast, infection resulted in significant changes in 30 genes governing innate and adaptive immunity including those for: the inflammatory response, host defense against bacteria, cytokines, chemokines, and an antibacterial humoral response. Intriguingly, following incubation of C. pneumoniae-infected cells with the acALY18 peptide (25-50nM) at 24hr post-infection, there was significant clearance of the organism from the monocytes as well as up-regulation of 38 genes. Our data suggest that C. pneumoniae infection of monocytes has a profound effect on gene regulation for both innate and adaptive immunity and for Alzheimer’s disease. Stimulating the innate immune response using the novel peptide, acALY18, promotes clearance of C. pneumoniae from infected monocytes; thereby implicating the inflammasome as a key component in eradicating this infection.https://digitalcommons.pcom.edu/posters/1005/thumbnail.jp

    Energieprijzen en emissiehandel

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    Elektriciteitsbedrijven maken windfall profi ts door gratis verkregen CO2-emissierechten. Deze windfall profi ts wil de Europese Commissie elimineren door de rechten te veilen. Dat elektriciteitsbedrijven windfall profi ts incasseren is echter economisch gezien geen probleem. Het gebruik van de gratis verstrekte emissierechten brengt immers kosten met zich mee, namelijk de alternatieve kosten (opportunity costs), verbonden aan het afzien van de verkoop van de rechten. Windfall profi ts vormen echter wel een politiek probleem, omdat aandeelhouders er rijker van worden. Veilen lost dat weliswaar op, maar introduceert ook nieuwe politieke problemen, bijvoorbeeld rond de verdeling van de opbrengsten en de concurrentie met bedrijven buiten het emissiehandelssysteem

    Electrochemically Generated Acid and Its Containment to 100 Micron Reaction Areas for the Production of DNA Microarrays

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    An addressable electrode array was used for the production of acid at sufficient concentration to allow deprotection of the dimethoxytrityl (DMT) protecting group from an overlaying substrate bound to a porous reaction layer. Containment of the generated acid to an active electrode of 100 micron diameter was achieved by the presence of an organic base. This procedure was then used for the production of a DNA array, in which synthesis was directed by the electrochemical removal of the DMT group during synthesis. The product array was found to have a detection sensitivity to as low as 0.5 pM DNA in a complex background sample

    Comparisons between Chemical Mapping and Binding to Isoenergetic Oligonucleotide Microarrays Reveal Unexpected Patterns of Binding to the Bacillus subtilis RNase P RNA Specificity Domain†

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    ABSTRACT: Microarrays with isoenergetic pentamer and hexamer 20-O-methyl oligonucleotide probes with LNA (locked nucleic acid) and 2,6-diaminopurine substitutions were used to probe the binding sites on theRNase P RNA specificity domain of Bacillus subtilis. Unexpected binding patterns were revealed. Because of their enhanced binding free energies, isoenergetic probes can break short duplexes, merge adjacent loops, and/or induce refolding. This suggests new approaches to the rational design of short oligonucleotide therapeutics but limits the utility of microarrays for providing constraints for RNA structure determination. The microarray results are compared to results from chemical mapping experiments, which do provide constraints. Results from both types of experiments indicate that the RNase P RNA folds similarly in 1MNaþ and 10 mMMg2þ. Binding of RNA to RNA is important for many natural func-tions, includingproteinsynthesis (1,2), translationregulation (3,4), gene silencing (5, 6), metabolic regulation (7), RNAmodification (8, 9), etc. (10-13). Binding of oligonucleotides toRNAs is impor-tant for therapeutic approaches, such as siRNA, ribozymes, and antisense therapy (14, 15).Much remains to bediscovered, however, of the rules for predicting binding sites andpotential therapeutics

    Evolution of the Toarcian (Early Jurassic) carbon-cycle and global climatic controls on local sedimentary processes (Cardigan Bay Basin, UK)

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    The late Early Jurassic Toarcian Stage represents the warmest interval of the Jurassic Period, with an abrupt rise in global temperatures of up to ∼7 °C in mid-latitudes at the onset of the early Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma). The T-OAE, which has been extensively studied in marine and continental successions from both hemispheres, was marked by the widespread expansion of anoxic and euxinic waters, geographically extensive deposition of organic-rich black shales, and climatic and environmental perturbations. Climatic and environmental processes following the T-OAE are, however, poorly known, largely due to a lack of study of stratigraphically well-constrained and complete sedimentary archives. Here, we present integrated geochemical and physical proxy data (high-resolution carbon-isotope data (δ13C), bulk and molecular organic geochemistry, inorganic petrology, mineral characterisation, and major- and trace-element concentrations) from the biostratigraphically complete and expanded entire Toarcian succession in the Llanbedr (Mochras Farm) Borehole, Cardigan Bay Basin, Wales, UK. With these data, we (1) construct the first high-resolution biostratigraphically calibrated chemostratigraphic reference record for nearly the complete Toarcian Stage, (2) establish palaeoceanographic and depositional conditions in the Cardigan Bay Basin, (3) show that the T-OAE in the hemipelagic Cardigan Bay Basin was marked by the occurrence of gravity-flow deposits that were likely linked to globally enhanced sediment fluxes to continental margins and deeper marine (shelf) basins, and (4) explore how early Toarcian (tenuicostatum and serpentinum zones) siderite formation in the Cardigan Bay Basin may have been linked to low global oceanic sulphate concentrations and elevated supply of iron (Fe) from the hinterland, in response to climatically induced changes in hydrological cycling, global weathering rates and large-scale sulphide and evaporite deposition
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