378 research outputs found

    A view on the internal consistency of linear source identification for I.C. engine exhaust noise prediction

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    [EN] Considerable efforts have been devoted to the development of predictive models that, from a certain set of data related to an engine, and making use of an adequate representation of the effect of the silencing elements, provide an estimate of the exhaust noise emitted. Such models should allow for the consideration of the engine and its interaction with the exhaust system. This is properly achieved by gas-dynamic models, which are becoming the standard, but linear models solved in the frequency domain and representing the engine as a linear time-invariant source may still play a role in exhaust system design, as the engine is treated as a black box. Such a representation is very attractive for engine manufacturers, since it gives the possibility to provide data on the engine without any possibility to trace back to its real characteristics. In order to provide additional criteria for the suitability of the application of a linear time-invariant representation to an engine exhaust, in this paper a multi-load method has been used to extract source characteristics from gas-dynamic simulation results. The details of the method, in which the resulting over-determined system is solved by fitting the values of the source parameters in a least-squares sense, are described, and different approaches are used in order to check the internal consistency of the source representation: the identification of pressure and velocity sources, and the application of the least-squares criterion to the modulus or to the real and imaginary parts separately. In particular, eight different determinations of the source impedance are obtained and, considering the application of the formalism to an engine exhaust, the differences observed provide a suitable criterion for the evaluation of the suitability of the representation and of the particular set of loads chosen.Macian Martinez, V.; Torregrosa Huguet, AJ.; Broatch, A.; Niven, P.; Amphlett, S. (2013). A view on the internal consistency of linear source identification for I.C. engine exhaust noise prediction. Mathematical and Computer Modelling. 57(7-8):1867-1875. doi:10.1016/j.mcm.2011.12.018S18671875577-

    Effect of Genetically Modified Organisms Feed Ingredients (Corn And Soybean) in Diet on Egg Production, Egg Broken Rate and Egg Quality in Layers

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    ABSTRACT This study was conducted to examine the effect of feeding genetically modified organisms (GMO) compared with non - GMO diet on performance of layers in terms of egg production, egg broken rate and egg quality in laying hen. One hundred and ninety-two Hy-line brown laying hens were used in the feeding for four weeks. All the birds were randomly assigned into two dietary treatments groups, each with eight replicates (12 hens/ replicate). Significant difference was not found in egg production in layers fed GMO feed in diet compared with the non - GMO treatment. Whereas in terms of egg quality, a significant increase was observed in yolk color and eggshell thickness of layers fed GMO diet compared with layers fed non-GMO diet at 1st week. Additionally, there was a significant increase in eggshell thickness of layers fed GMO diet compared with layers fed non - GMO diet at 2nd, and 4th week. Layers fed GMO diet showed higher egg yolk value compared to the non-GMO diet in 1st week. However, no significant differences were found in other profiles such as egg quality including egg weight, albumen height, haugh units, shell color, and shell strength from 1st to 4th week since layers fed GMO. In conclusion, layers fed GMO diet showed significant improvement in eggshell thickness and yolk color and no significant difference was found in egg production. Layers fed GMO diets may enhance the egg quality, and further research need to be done

    Pontin functions as an essential coactivator for Oct4-dependent lincRNA expression in mouse embryonic stem cells

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    The actions of transcription factors, chromatin modifiers and noncoding RNAs are crucial for the programming of cell states. Although the importance of various epigenetic machineries for controlling pluripotency of embryonic stem (ES) cells has been previously studied, how chromatin modifiers cooperate with specific transcription factors still remains largely elusive. Here, we find that Pontin chromatin remodelling factor plays an essential role as a coactivator for Oct4 for maintenance of pluripotency in mouse ES cells. Genome-wide analyses reveal that Pontin and Oct4 share a substantial set of target genes involved in ES cell maintenance. Intriguingly, we find that the Oct4-dependent coactivator function of Pontin extends to the transcription of large intergenic noncoding RNAs (lincRNAs) and in particular linc1253, a lineage programme repressing lincRNA, is a Pontin-dependent Oct4 target lincRNA. Together, our findings demonstrate that the Oct4-Pontin module plays critical roles in the regulation of genes involved in ES cell fate determination.111311Ysciescopu

    Changing presentation of prostate cancer in a UK population--10 year trends in prostate cancer risk profiles in the East of England.

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    BACKGROUND: Prostate cancer incidence is rising in the United Kingdom but there is little data on whether the disease profile is changing. To address this, we interrogated a regional cancer registry for temporal changes in presenting disease characteristics. METHODS: Prostate cancers diagnosed from 2000 to 2010 in the Anglian Cancer Network (n=21,044) were analysed. Risk groups (localised disease) were assigned based on NICE criteria. Age standardised incidence rates (IRs) were compared between 2000-2005 and 2006-2010 and plotted for yearly trends. RESULTS: Over the decade, overall IR increased significantly (P<0.00001), whereas metastasis rates fell (P<0.0007). For localised disease, IR across all risk groups also increased but at different rates (P<0.00001). The most striking change was a three-fold increase in intermediate-risk cancers. Increased IR was evident across all PSA and stage ranges but with no upward PSA or stage shift. In contrast, IR of histological diagnosis of low-grade cancers fell over the decade, whereas intermediate and high-grade diagnosis increased significantly (P<0.00001). CONCLUSION: This study suggests evidence of a significant upward migration in intermediate and high-grade histological diagnosis over the decade. This is most likely to be due to a change in histological reporting of diagnostic prostate biopsies. On the basis of this data, increasing proportions of newly diagnosed cancers will be considered eligible for radical treatment, which will have an impact on health resource planning and provision

    A poisson regression approach for modelling spatial autocorrelation between geographically referenced observations

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    Abstract Background Analytic methods commonly used in epidemiology do not account for spatial correlation between observations. In regression analyses, omission of that autocorrelation can bias parameter estimates and yield incorrect standard error estimates. Methods We used age standardised incidence ratios (SIRs) of esophageal cancer (EC) from the Babol cancer registry from 2001 to 2005, and extracted socioeconomic indices from the Statistical Centre of Iran. The following models for SIR were used: (1) Poisson regression with agglomeration-specific nonspatial random effects; (2) Poisson regression with agglomeration-specific spatial random effects. Distance-based and neighbourhood-based autocorrelation structures were used for defining the spatial random effects and a pseudolikelihood approach was applied to estimate model parameters. The Bayesian information criterion (BIC), Akaike's information criterion (AIC) and adjusted pseudo R2, were used for model comparison. Results A Gaussian semivariogram with an effective range of 225 km best fit spatial autocorrelation in agglomeration-level EC incidence. The Moran's I index was greater than its expected value indicating systematic geographical clustering of EC. The distance-based and neighbourhood-based Poisson regression estimates were generally similar. When residual spatial dependence was modelled, point and interval estimates of covariate effects were different to those obtained from the nonspatial Poisson model. Conclusions The spatial pattern evident in the EC SIR and the observation that point estimates and standard errors differed depending on the modelling approach indicate the importance of accounting for residual spatial correlation in analyses of EC incidence in the Caspian region of Iran. Our results also illustrate that spatial smoothing must be applied with care.</p

    The pharmacological regulation of cellular mitophagy

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    Small molecules are pharmacological tools of considerable value for dissecting complex biological processes and identifying potential therapeutic interventions. Recently, the cellular quality-control process of mitophagy has attracted considerable research interest; however, the limited availability of suitable chemical probes has restricted our understanding of the molecular mechanisms involved. Current approaches to initiate mitophagy include acute dissipation of the mitochondrial membrane potential (ΔΨm) by mitochondrial uncouplers (for example, FCCP/CCCP) and the use of antimycin A and oligomycin to impair respiration. Both approaches impair mitochondrial homeostasis and therefore limit the scope for dissection of subtle, bioenergy-related regulatory phenomena. Recently, novel mitophagy activators acting independently of the respiration collapse have been reported, offering new opportunities to understand the process and potential for therapeutic exploitation. We have summarized the current status of mitophagy modulators and analyzed the available chemical tools, commenting on their advantages, limitations and current applications

    Isolation of Foreign Material-Free Endothelial Progenitor Cells Using CD31 Aptamer and Therapeutic Application for Ischemic Injury

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    Endothelial progenitor cells (EPCs) can be isolated from human bone marrow or peripheral blood and reportedly contribute to neovascularization. Aptamers are 40-120-mer nucleotides that bind to a specific target molecule, as antibodies do. To utilize apatmers for isolation of EPCs, in the present study, we successfully generated aptamers that recognize human CD31, an endothelial cell marker. CD31 aptamers bound to human umbilical cord blood-derived EPCs and showed specific interaction with human CD31, but not with mouse CD31. However, CD31 aptamers showed non-specific interaction with CD31-negative 293FT cells and addition of polyanionic competitor dextran sulfate eliminated non-specific interaction without affecting cell viability. From the mixture of EPCs and 293FT cells, CD31 aptamers successfully isolated EPCs with 97.6% purity and 94.2% yield, comparable to those from antibody isolation. In addition, isolated EPCs were decoupled from CD31 aptamers with a brief treatment of high concentration dextran sulfate. EPCs isolated with CD31 aptamers and subsequently decoupled from CD31 aptamers were functional and enhanced the restoration of blood flow when transplanted into a murine hindlimb ischemia model. In this study, we demonstrated isolation of foreign material-free EPCs, which can be utilized as a universal protocol in preparation of cells for therapeutic transplantation.1164Ysciescopu

    Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

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    Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD

    Extracting causal relations on HIV drug resistance from literature

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    <p>Abstract</p> <p>Background</p> <p>In HIV treatment it is critical to have up-to-date resistance data of applicable drugs since HIV has a very high rate of mutation. These data are made available through scientific publications and must be extracted manually by experts in order to be used by virologists and medical doctors. Therefore there is an urgent need for a tool that partially automates this process and is able to retrieve relations between drugs and virus mutations from literature.</p> <p>Results</p> <p>In this work we present a novel method to extract and combine relationships between HIV drugs and mutations in viral genomes. Our extraction method is based on natural language processing (NLP) which produces grammatical relations and applies a set of rules to these relations. We applied our method to a relevant set of PubMed abstracts and obtained 2,434 extracted relations with an estimated performance of 84% for F-score. We then combined the extracted relations using logistic regression to generate resistance values for each <drug, mutation> pair. The results of this relation combination show more than 85% agreement with the Stanford HIVDB for the ten most frequently occurring mutations. The system is used in 5 hospitals from the Virolab project <url>http://www.virolab.org</url> to preselect the most relevant novel resistance data from literature and present those to virologists and medical doctors for further evaluation.</p> <p>Conclusions</p> <p>The proposed relation extraction and combination method has a good performance on extracting HIV drug resistance data. It can be used in large-scale relation extraction experiments. The developed methods can also be applied to extract other type of relations such as gene-protein, gene-disease, and disease-mutation.</p
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