1,209 research outputs found

    SPINNING STRAW INTO GOLD: TURNING ACADEMIC PAPERS INTO COMMERCIAL FLUIDIZED BED REACTOR SOLUTIONS

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    This paper presents an example of academic work that has been applied in industry. A case is presented of a solution to a serious operational problem involving fluidization phenomena threatening to cause structural damage to an operating chemical reactor. The process used to analyze the problem and arrive at a probable cause and design solutions are presented

    Hierarchical Gaussian process mixtures for regression

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    As a result of their good performance in practice and their desirable analytical properties, Gaussian process regression models are becoming increasingly of interest in statistics, engineering and other fields. However, two major problems arise when the model is applied to a large data-set with repeated measurements. One stems from the systematic heterogeneity among the different replications, and the other is the requirement to invert a covariance matrix which is involved in the implementation of the model. The dimension of this matrix equals the sample size of the training data-set. In this paper, a Gaussian process mixture model for regression is proposed for dealing with the above two problems, and a hybrid Markov chain Monte Carlo (MCMC) algorithm is used for its implementation. Application to a real data-set is reported

    Artificial Neural Network-based error compensation procedure for low-cost encoders

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    An Artificial Neural Network-based error compensation method is proposed for improving the accuracy of resolver-based 16-bit encoders by compensating for their respective systematic error profiles. The error compensation procedure, for a particular encoder, involves obtaining its error profile by calibrating it on a precision rotary table, training the neural network by using a part of this data and then determining the corrected encoder angle by subtracting the ANN-predicted error from the measured value of the encoder angle. Since it is not guaranteed that all the resolvers will have exactly similar error profiles because of the inherent differences in their construction on a micro scale, the ANN has been trained on one error profile at a time and the corresponding weight file is then used only for compensating the systematic error of this particular encoder. The systematic nature of the error profile for each of the encoders has also been validated by repeated calibration of the encoders over a period of time and it was found that the error profiles of a particular encoder recorded at different epochs show near reproducible behavior. The ANN-based error compensation procedure has been implemented for 4 encoders by training the ANN with their respective error profiles and the results indicate that the accuracy of encoders can be improved by nearly an order of magnitude from quoted values of ~6 arc-min to ~0.65 arc-min when their corresponding ANN-generated weight files are used for determining the corrected encoder angle.Comment: 16 pages, 4 figures. Accepted for Publication in Measurement Science and Technology (MST

    MTORC1 promotes T-bet phosphorylation to regulate Th1 differentiation

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    CD4+ T cells lacking the mTORC1 activator Rheb fail to secrete IFN-g under Th1 polarizing conditions. We hypothesized that this phenotype is due to defects in regulation of the canonical Th1 transcription factor T-bet at the level of protein phosphorylation downstream of mTORC1. To test this hypothesis, we employed targeted mass-spectrometry proteomic analysis-multiple reaction monitoring mass spectrometry. We used this method to detect and quantify predicted phosphopeptides derived from T-bet. By analyzing activated murine wild-type and Rheb-deficient CD4+ T cells, as well as murine CD4+ T cells activated in the presence of rapamycin, a pharmacologic inhibitor of mTORC1, we were able to identify six T-bet phosphorylation sites. Five of these are novel, and four sites are consistently dephosphorylated in both Rheb-deficient CD4+ T cells and T cells treated with rapamycin, suggesting mTORC1 signaling controls their phosphorylation. Alanine mutagenesis of each of the six phosphorylation sites was tested for the ability to impair IFN-g expression. Single phosphorylation site mutants still support induction of IFN-g expression; however, simultaneous mutation of three of the mTORC1-dependent sites results in significantly reduced IFN-g expression. The reduced activity of the triple mutant T-bet is associated with its failure to recruit chromatin remodeling complexes to the Ifng gene promoter. These results establish a novel mechanism by which mTORC1 regulates Th1 differentiation, through control of T-bet phosphorylation

    Quantum effects in linguistic endeavors

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    Classifying the information content of neural spike trains in a linguistic endeavor, an uncertainty relation emerges between the bit size of a word and its duration. This uncertainty is associated with the task of synchronizing the spike trains of different duration representing different words. The uncertainty involves peculiar quantum features, so that word comparison amounts to measurement-based-quantum computation. Such a quantum behavior explains the onset and decay of the memory window connecting successive pieces of a linguistic text. The behavior here discussed is applicable to other reported evidences of quantum effects in human linguistic processes, so far lacking a plausible framework, since either no efforts to assign an appropriate quantum constant had been associated or speculating on microscopic processes dependent on Planck's constant resulted in unrealistic decoherence times

    Deep interference minima in non-coplanar triple differential cross sections for the electron-impact ionization of small atoms and molecules

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    Abstract The time-dependent close-coupling method and a distorted-wave approach are used to explore deep minima discovered in the non-coplanar triple differential cross sections for the electron-impact ionization of helium. This phenomenon has been well studied experimentally but so far has not been investigated by a non-perturbative theoretical approach. We find that our time-dependent calculations reproduce very well the experimental minima, and that the distorted-wave calculations also confirm this phenomenon. Further investigations reveal that the minima appear to be due to deep destructive interference between the partial wave contributions which make up the cross sections. We also show that similar minima may be found in triple differential cross sections arising from the electron-impact ionization of atomic and molecular hydrogen

    Defect Statistics in the Two Dimensional Complex Ginsburg-Landau Model

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    The statistical correlations between defects in the two dimensional complex Ginsburg-Landau model are studied in the defect-coarsening regime. In particular the defect-velocity probability distribution is determined and has the same high velocity tail found for the purely dissipative time-dependent Ginsburg-Landau (TDGL) model. The spiral arms of the defects lead to a very different behavior for the order parameter correlation function in the scaling regime compared to the results for the TDGL model.Comment: 24 page

    Reduction of Murine Colon Tumorigenesis Driven by Enterotoxigenic Bacteroides fragilis Using Cefoxitin Treatment

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    BACKGROUND: Chronic inflammation and composition of the colon microbiota have been associated with colorectal cancer in humans. The human commensal enterotoxigenic Bacteroides fragilis (ETBF) is linked to both inflammatory bowel disease and colorectal cancer and, in our murine model, causes interleukin 17A (IL-17A)-dependent colon tumors. In these studies, we hypothesized that persistent colonization by ETBF is required for tumorigenesis. METHODS: We established a method for clearing ETBF in mice, using the antibiotic cefoxitin. Multiple intestinal neoplasia mice were colonized with ETBF for the experiment duration or were cleared of infection after 5 or 14 days. Gross tumors and/or microadenomas were then evaluated. In parallel, IL-17A expression was evaluated in wild-type littermates. RESULTS: Cefoxitin treatment resulted in complete and durable clearance of ETBF colonization. We observed a stepwise increase in median colon tumor numbers as the duration of ETBF colonization increased before cefoxitin treatment. ETBF eradication also significantly decreased mucosal IL-17A expression. CONCLUSIONS: The timing of ETBF clearance profoundly influences colon adenoma formation, defining a period during which the colon is susceptible to IL-17A-dependent tumorigenesis in this murine model. This model system can be used to study the microbiota-dependent and molecular mechanisms contributing to IL-17A-dependent colon tumor initiation
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