220 research outputs found

    Initial Investigation of Analytic Hierarchy Process to Teach Creativity in Design and Engineering

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    This paper investigates the use of Analytic Hierarchy Process to teach design creativity and innovation in undergraduate engineering students. Examples are included to assess its effectiveness in the classroom. The purpose of this research is to investigate the suitability of the Analytic Hierarchy Process (AHP) to teach design innovation and creativity in undergraduate engineering classrooms. AHP is a very structured, multi-criteria, decision-making process and traditionally has been used to solve complex problem sets. This investigation takes a fresh look at how AHP provides the framework to engage and encourage students to think creatively and innovatively in design and engineering. This paper presents several separate case studies that incorporate the AHP technique in the classroom to teach design innovation and creativity to undergraduate engineering students, including introduction at the freshmen engineering level. These case studies include: the design of a robotic water vehicle; the design of a coffee maker; and the design of a website. These diverse case studies explore the suitability of this decision-making technique across abroad range of design problems to assess how AHP can be utilized to give students a better understanding of the design process, to foster a personal motivation towards creative and innovative thinking and to equip students with a strategy for creative problem solving theycan use through their engineering careers. Students who participated in the case studies completed questionnaires to assess the application of AHP and its effectiveness to understand the problem and to reach a creative and innovative solution. Based on the results of these student questionnaires, there is positive evidence that AHP can be utilized to remove barriers that inhibit creativity and to foster an environment for students to achieve more design creativity and innovation in engineering classrooms. This study has implications to change the pedagogical approach used to teach engineering design and provides a methodology for design creativity that students will carry with them throughout their career

    A metaproteomic approach to study human-microbial ecosystems at the mucosal luminal interface

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    Aberrant interactions between the host and the intestinal bacteria are thought to contribute to the pathogenesis of many digestive diseases. However, studying the complex ecosystem at the human mucosal-luminal interface (MLI) is challenging and requires an integrative systems biology approach. Therefore, we developed a novel method integrating lavage sampling of the human mucosal surface, high-throughput proteomics, and a unique suite of bioinformatic and statistical analyses. Shotgun proteomic analysis of secreted proteins recovered from the MLI confirmed the presence of both human and bacterial components. To profile the MLI metaproteome, we collected 205 mucosal lavage samples from 38 healthy subjects, and subjected them to high-throughput proteomics. The spectral data were subjected to a rigorous data processing pipeline to optimize suitability for quantitation and analysis, and then were evaluated using a set of biostatistical tools. Compared to the mucosal transcriptome, the MLI metaproteome was enriched for extracellular proteins involved in response to stimulus and immune system processes. Analysis of the metaproteome revealed significant individual-related as well as anatomic region-related (biogeographic) features. Quantitative shotgun proteomics established the identity and confirmed the biogeographic association of 49 proteins (including 3 functional protein networks) demarcating the proximal and distal colon. This robust and integrated proteomic approach is thus effective for identifying functional features of the human mucosal ecosystem, and a fresh understanding of the basic biology and disease processes at the MLI. © 2011 Li et al

    An iterative approach of protein function prediction

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    Background: Current approaches of predicting protein functions from a protein-protein interaction (PPI) dataset are based on an assumption that the available functions of the proteins (a.k.a. annotated proteins) will determine the functions of the proteins whose functions are unknown yet at the moment (a.k.a. un-annotated proteins). Therefore, the protein function prediction is a mono-directed and one-off procedure, i.e. from annotated proteins to un-annotated proteins. However, the interactions between proteins are mutual rather than static and mono-directed, although functions of some proteins are unknown for some reasons at present. That means when we use the similarity-based approach to predict functions of un-annotated proteins, the un-annotated proteins, once their functions are predicted, will affect the similarities between proteins, which in turn will affect the prediction results. In other words, the function prediction is a dynamic and mutual procedure. This dynamic feature of protein interactions, however, was not considered in the existing prediction algorithms.Results: In this paper, we propose a new prediction approach that predicts protein functions iteratively. This iterative approach incorporates the dynamic and mutual features of PPI interactions, as well as the local and global semantic influence of protein functions, into the prediction. To guarantee predicting functions iteratively, we propose a new protein similarity from protein functions. We adapt new evaluation metrics to evaluate the prediction quality of our algorithm and other similar algorithms. Experiments on real PPI datasets were conducted to evaluate the effectiveness of the proposed approach in predicting unknown protein functions.Conclusions: The iterative approach is more likely to reflect the real biological nature between proteins when predicting functions. A proper definition of protein similarity from protein functions is the key to predicting functions iteratively. The evaluation results demonstrated that in most cases, the iterative approach outperformed non-iterative ones with higher prediction quality in terms of prediction precision, recall and F-value

    Induced proximity of a TIR signaling domain on a plant-mammalian NLR chimera activates defense in plants

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    Plant and animal intracellular nucleotide-binding, leucine-rich repeat (NLR) immune receptors detect pathogen-derived molecules and activate defense. Plant NLRs can be divided into several classes based upon their N-terminal signaling domains, including TIR (Toll-like, Interleukin-1 receptor, Resistance protein)- and CC (coiled-coil)-NLRs. Upon ligand detection, mammalian NAIP and NLRC4 NLRs oligomerize, forming an inflammasome that induces proximity of its N-terminal signaling domains. Recently, a plant CC-NLR was revealed to form an inflammasome-like hetero-oligomer. To further investigate plant NLR signaling mechanisms, we fused the N-terminal TIR domain of several plant NLRs to the N terminus of NLRC4. Inflammasome-dependent induced proximity of the TIR domain in planta initiated defense signaling. Thus, induced proximity of a plant TIR domain imposed by oligomerization of a mammalian inflammasome is sufficient to activate authentic plant defense. Ligand detection and inflammasome formation is maintained when the known components of the NLRC4 inflammasome is transferred across kingdoms, indicating that NLRC4 complex can robustly function without any additional mammalian proteins. Additionally, we found NADase activity of a plant TIR domain is necessary for plant defense activation, but NADase activity of a mammalian or a bacterial TIR is not sufficient to activate defense in plants

    Probing composition distributions in nanoalloy catalysts with correlative electron microscopy

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    Alloyed nanoparticles are important functional materials and have wide applications especially in heterogeneous catalysis and electrocatalysis. Controlled synthesis of nanoalloys is desirable in order to understand their structure–property relationships and further optimize their performance. While many synthesis methods have been developed, information on the resultant composition distributions among particles is often not available, and uniformity of composition from particle-to-particle is often incorrectly assumed. Such an analysis would require extensive work on a high-resolution analytical electron microscope, which has some drawbacks and the high-resolution equipment is not always readily accessible. We hereby introduce an alternative way for composition analysis of nanoalloys via a correlative electron microscopy approach, separating the size measurement (imaging) and composition analysis between TEM and SEM instruments. Using a case study of two AuPd nanoalloys which have very similar size distributions but significantly different composition distributions and catalytic activities, we demonstrate both the necessity of performing composition distribution analysis on ultrasmall nanoalloys and the feasibility of this method. We show that a more efficient X-ray analysis on nanoalloys can be done in an SEM due to intrinsically higher ionization cross-sections from the relatively lower energy (e.g. 20 keV) electron beam and the possibility of using large probe currents and X-ray detectors with large collection angles

    Global climate forcing of aerosols embodied in international trade

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    International trade separates regions consuming goods and services from regions where goods and related aerosol pollution are produced. Yet the role of trade in aerosol climate forcing attributed to different regions has never been quantified. Here, we contrast the direct radiative forcing of aerosols related to regions’ consumption of goods and services against the forcing due to emissions produced in each region. Aerosols assessed include black carbon, primary organic aerosol, and secondary inorganic aerosols, including sulfate, nitrate and ammonium. We find that global aerosol radiative forcing due to emissions produced in East Asia is much stronger than the forcing related to goods and services ultimately consumed in that region because of its large net export of emissions-intensive goods. The opposite is true for net importers such as Western Europe and North America: global radiative forcing related to consumption is much greater than the forcing due to emissions produced in these regions. Overall, trade is associated with a shift of radiative forcing from net importing to net exporting regions. Compared to greenhouse gases such as carbon dioxide, the short atmospheric lifetimes of aerosols cause large localized differences between consumption- and production-related radiative forcing. International efforts to reduce emissions in the exporting countries will help alleviate trade-related climate and health impacts of aerosols while lowering global emissions

    Efficient Capture of Infected Neutrophils by Dendritic Cells in the Skin Inhibits the Early Anti-Leishmania Response

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    Neutrophils and dendritic cells (DCs) converge at localized sites of acute inflammation in the skin following pathogen deposition by the bites of arthropod vectors or by needle injection. Prior studies in mice have shown that neutrophils are the predominant recruited and infected cells during the earliest stage of Leishmania major infection in the skin, and that neutrophil depletion promotes host resistance to sand fly transmitted infection. How the massive influx of neutrophils aimed at wound repair and sterilization might modulate the function of DCs in the skin has not been previously addressed. The infected neutrophils recovered from the skin expressed elevated apoptotic markers compared to uninfected neutrophils, and were preferentially captured by dermal DCs when injected back into the mouse ear dermis. Following challenge with L. major directly, the majority of the infected DCs recovered from the skin at 24 hr stained positive for neutrophil markers, indicating that they acquired their parasites via uptake of infected neutrophils. When infected, dermal DCs were recovered from neutrophil depleted mice, their expression of activation markers was markedly enhanced, as was their capacity to present Leishmania antigens ex vivo. Neutrophil depletion also enhanced the priming of L. major specific CD4+ T cells in vivo. The findings suggest that following their rapid uptake by neutrophils in the skin, L. major exploits the immunosuppressive effects associated with the apoptotic cell clearance function of DCs to inhibit the development of acquired resistance until the acute neutrophilic response is resolved
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