3,803 research outputs found

    Bioethanol from Germinated Grains.

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    The most well-known way to produce bioethanol is by the enzymatic hydrolysis and fermentation of starch. In a new project “BioConcens” (2007) sponsored by DARCOF (DAnish Research Center for Organic Food and farming) one aim is to develop a combined ethanol and biogas production for use in organic farming using starch containing biomass. Natural enzymes from cereals will be used for hydrolysis of starch to glucose in accordance with technology in brewing technology. Commercial enzymes are often produced from gene-modified organisms and will therefore not be used in the suggested organic context or process. A preliminary study was performed in which grains of wheat, rye, and barley were germinated using traditional methods applied in malting for beer production. During malting the amylase enzymes present in the grain are activated (autoamylolytic effect). Three steps were applied in the malting process; steeping, germination, and drying of the grains. After malting the grains were milled and mixed with water to 13% DM, cooked at 57.5C for 2 hours (to activate the enzymes), and cooled to 30C before adding Bakers Yeast. The results of this study indicate that efficient hydrolysis of starch can be achieved by activation of autoamylolytic enzymes in cereal grains after a malting process. The ethanol yields obtained in the autoamylolytic hydrolysis was comparable (or slightly higher) to that of reference experiments using commercial enzymes (amylases). The highest ethanol yield was obtained with wheat (0.34 g/g DM grain), followed by barley (0.31 g/g DM grain), and rye (0.29 g/g DM grain)

    Sustainable bioethanol production combining biorefinery principles using combined raw materials from wheat undersown with clover-grass

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    To obtain the best possible net energy balance of the bioethanol production the biomass raw materials used need to be produced with limited use of non-renewable fossil fuels. Intercropping strategies are known to maximize growth and productivity by including more than one species in the crop stand, very often with legumes as one of the components. In the present study clover-grass is undersown in a traditional wheat crop. Thereby, it is possible to increase input of symbiotic fixation of atmospheric nitrogen into the cropping systems and reduce the need for fertilizer applications. Furthermore, when using such wheat and clover-grass mixtures as raw material, addition of urea and other fermentation nutrients produced from fossil fuels can be reduced in the whole ethanol manufacturing chain. Using second generation ethanol technology mixtures of relative proportions of wheat straw and clover-grass (15:85, 50:50, and 85:15) were pretreated by wet oxidation. The results showed that supplementing wheat straw with clover-grass had a positive effect on the ethanol yield in simultaneous saccharification and fermentation experiments, and the effect was more pronounced in inhibitory substrates. The highest ethanol yield (80% of theoretical) was obtained in the experiment with high fraction (85%) of clover-grass. In order to improve the sugar recovery of clover-grass, it should be separated into a green juice (containing free sugars, fructan, amino acids, vitamins and soluble minerals) for direct fermentation and a fibre pulp for pretreatment together with wheat straw. Based on the obtained results a decentralized biorefinery concept for production of biofuel is suggested emphasizing sustainability, localness, and recycling principle

    Conformally rescaled spacetimes and Hawking radiation

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    We study various derivations of Hawking radiation in conformally rescaled metrics. We focus on two important properties, the location of the horizon under a conformal transformation and its associated temperature. We find that the production of Hawking radiation cannot be associated in all cases to the trapping horizon because its location is not invariant under a conformal transformation. We also find evidence that the temperature of the Hawking radiation should transform simply under a conformal transformation, being invariant for asymptotic observers in the limit that the conformal transformation factor is unity at their location.Comment: 22 pages, version submitted to journa

    Externally validated model predicting gait independence after stroke showed fair performance and improved after updating

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    ObjectiveTo externally validate recent prognostic models that predict independent gait following stroke.Study design and settingA systematic search identified recent models (ResultsThree prognostic models met our criteria, all with high Risk of Bias. Validation data was only available for the Australian model. This model used National Institute of Health Stroke Scale (NIHSS) and age to predict independent gait, using Motor Assessment Scale (MAS) walking item. For validation, Scandinavian Stroke Scale (SSS) was a proxy for NIHSS, and Functional Independence Measure (FIM) locomotion item was a proxy for MAS. The Area Under the Curve was 0.77 (0.74-0.80) and had good calibration in the validation dataset. Adjustment of the intercept and regression coefficients slightly improved discrimination. By adding paretic leg strength, the model further improved (AUC 0.82).ConclusionExternal validation of the Australian model with proxies showed fair discrimination and good calibration. Updating the model by adding paretic leg strength further improved model performance

    Hopf algebras, coproducts and symbols: an application to Higgs boson amplitudes

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    We show how the Hopf algebra structure of multiple polylogarithms can be used to simplify complicated expressions for multi-loop amplitudes in perturbative quantum field theory and we argue that, unlike the recently popularized symbol-based approach, the coproduct incorporates information about the zeta values. We illustrate our approach by rewriting the two-loop helicity amplitudes for a Higgs boson plus three gluons in a simplified and compact form involving only classical polylogarithms.Comment: 46 page

    Individual variation in levels of haptoglobin-related protein in children from Gabon

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    Background: Haptoglobin related protein (Hpr) is a key component of trypanosome lytic factors (TLF), a subset of highdensity lipoproteins (HDL) that form the first line of human defence against African trypanosomes. Hpr, like haptoglobin (Hp) can bind to hemoglobin (Hb) and it is the Hpr-Hb complexes which bind to these parasites allowing uptake of TLF. This unique form of innate immunity is primate-specific. To date, there have been no population studies of plasma levels of Hpr, particularly in relation to hemolysis and a high prevalence of ahaptoglobinemia as found in malaria endemic areas. Methods and Principal Findings: We developed a specific enzyme-linked immunosorbent assay to measure levels of plasma Hpr in Gabonese children sampled during a period of seasonal malaria transmission when acute phase responses (APR), malaria infection and associated hemolysis were prevalent. Median Hpr concentration was 0.28 mg/ml (range 0.03-1.1). This was 5-fold higher than that found in Caucasian children (0.049 mg/ml, range 0.002-0.26) with no evidence of an APR. A general linear model was used to investigate associations between Hpr levels, host polymorphisms, parasitological factors and the acute phase proteins, Hp, C-reactive protein (CRP) and albumin. Levels of Hpr were associated with Hp genotype, decreased with age and were higher in females. Hpr concentration was strongly correlated with that of Hp, but not CRP

    CCL2 recruits inflammatory monocytes to facilitate breast-tumour metastasis

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    Macrophages abundantly found in the tumor microenvironment enhance malignancy(1). At metastatic sites a distinct population of metastasis associated macrophages (MAMs) promote tumor cell extravasation, seeding and persistent growth(2). Our study has defined the origin of these macrophages by showing Gr1+ inflammatory monocytes (IMs) are preferentially recruited to pulmonary metastases but not primary mammary tumors, a process also found for human IMs in pulmonary metastases of human breast cancer cells. The recruitment of these CCR2 (receptor for chemokine CCL2) expressing IMs and subsequently MAMs and their interaction with metastasizing tumor cells is dependent on tumor and stromal synthesized CCL2 (FigS1). Inhibition of CCL2/CCR2 signaling using anti-CCL2 antibodies blocks IM recruitment and inhibits metastasis in vivo and prolongs the survival of tumor-bearing mice. Depletion of tumor cell-derived CCL2 also inhibits metastatic seeding. IMs promote tumor cell extravasation in a process that requires monocyte-derived VEGF. CCL2 expression and macrophage infiltration are correlated with poor prognosis and metastatic disease in human breast cancer (Fig S2)(3-6). Our data provides the mechanistic link between these two clinical associations and indicates new therapeutic targets for treating metastatic breast disease

    Tooth development standards for South Australia

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: Chronological age, as recorded by registration of birth date, is referred to throughout an individual's life. This information is relevant in medical and dental practice for evaluating developmental progress, for educational purposes, and in legal matters, particularly in the application of criminal law. The absence of birth date information raises particular concerns, and estimates of chronological age are often required. Standards of dental maturation may be used to estimate age, but they have been shown to be gender and population sensitive. Methods: The revised Demirjian' system of dental age estimation was applied to a sample of 615 South Australian children in order to assess its accuracy. Results: The results of our study have shown that the Demirjian system is of limited accuracy when used to estimate the age of South Australian children. Conclusions: Generation of new standard curves, specific to the Australian population, is indicated.CJ McKenna, H James, JA Taylor, GC Townsen

    High-throughput, quantitative analyses of genetic interactions in E. coli.

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    Large-scale genetic interaction studies provide the basis for defining gene function and pathway architecture. Recent advances in the ability to generate double mutants en masse in Saccharomyces cerevisiae have dramatically accelerated the acquisition of genetic interaction information and the biological inferences that follow. Here we describe a method based on F factor-driven conjugation, which allows for high-throughput generation of double mutants in Escherichia coli. This method, termed genetic interaction analysis technology for E. coli (GIANT-coli), permits us to systematically generate and array double-mutant cells on solid media in high-density arrays. We show that colony size provides a robust and quantitative output of cellular fitness and that GIANT-coli can recapitulate known synthetic interactions and identify previously unidentified negative (synthetic sickness or lethality) and positive (suppressive or epistatic) relationships. Finally, we describe a complementary strategy for genome-wide suppressor-mutant identification. Together, these methods permit rapid, large-scale genetic interaction studies in E. coli
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