1,843 research outputs found

    Engineered thermostable fungal cellulases exhibit efficient synergistic cellulose hydrolysis at elevated temperatures

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    A major obstacle to using widely available and low-cost lignocellulosic feedstocks to produce renewable fuels and chemicals is the high cost and low efficiency of the enzyme mixtures used to hydrolyze cellulose to fermentable sugars. One possible solution entails engineering current cellulases to function efficiently at elevated temperatures in order to boost reaction rates and exploit several other advantages of a higher temperature process. Here we describe the creation of the most stable reported fungal endoglucanase, a derivative of Hypocrea jecorina (anamorph Trichoderma reesei) Cel5A, by combining stabilizing mutations identified using consensus design, chimera studies, and structure-based computational methods. The engineered endoglucanase has an optimal temperature that is 17 °C higher than wild type H. jecorina Cel5A, and hydrolyzes 1.5 times as much cellulose over 60 h at its optimum temperature compared to the wild type enzyme at its optimal temperature.This enzyme complements previously-engineered highly-active, thermostable variants of the fungal cellobiohydrolases Cel6A and Cel7A in a thermostable cellulase mixture that hydrolyzes cellulose synergistically at an optimum temperature of 70 °C over 60 h.The thermostable mixture produces three times as much total sugar as the best mixture of the wild type enzymes operating at its optimum temperature of 60 °C, clearly demonstrating the advantage of higher-temperature cellulose hydrolysis

    Aboriginal Education as Cultural Brokerage: New Aboriginal Teachers Reflect on Language and Culture in the Classroom

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    This paper reports on a Talking Circle of six beginning Aboriginal teachers who discussed their roles as teachers. Participants criticized teacher education programs for not preparing them to teach in ways that are respectful of Aboriginal languages and culture. They discussed the importance of coming to know themselves and their culture. The paper concludes with suggestions for decolonizing teacher preparation so that Aboriginal teachers are enabled as protectors of Aboriginal culture and brokers with Euro-Canadian culture. Cet article fait le compte-rendu des rĂ©vĂ©lations faites par six nouveaux enseignants d’origine autochtone au cours d’un cercle de discussion sur leur rĂŽle d’enseignant. Les participants ont reprochĂ© aux programmes de formation des maĂźtres de ne pas les prĂ©parer Ă  enseigner de maniĂšre respectueuse du langage et de la culture autochtones. Par ailleurs, ils ont soulignĂ© l’importance d’apprendre Ă  se connaĂźtre et Ă  explorer leur culture. En conclusion, les auteurs suggĂšrent des approches pour dĂ©coloniser la prĂ©paration des enseignants d’origine autochtone afin de leur permettre d’agir comme protecteurs de la culture autochtone et agents d’échange culturel avec la culture euro-canadienne

    Seismic vulnerability reduction: numerical modeling of FRP reinforcement using multifiber beams elements

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    This paper presents a simplified modeling strategy for reproducing the behavior of beam-column structures reinforced with Polymer Reinforced Fibers (FRP). A 1D concrete constitutive model has been recently proposed, suitable for both monotonic and cycling loadings. The model is inspired on two well-known concrete laws, one based on damage mechanics theory (La Borderie concrete damage model) and one based on experimental studies (Eid & Paultre's confined concrete model). Spatial discretization is done using multifiber Timoshenko beam elements. Validation of the strategy is provided using two case studies: a retrofitted bridge pier and a vulnerability analysis on an existing building

    Clinical trial update: National Cancer Institute of Canada

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    The Breast Cancer Site Group (BCSG) of the National Cancer Institute of Canada (NCIC) Clinical Trials Group (CTG) has conducted a wide variety of clinical trials focussing on large phase III trials of adjuvant chemotherapy, adjuvant hormonal therapy, and optimal delivery of adjuvant radiation therapy. The Group has also fostered, together with the NCIC CTG Investigational New Drug (IND) Program, a series of phase II and phase I/II studies which will be carried through if possible, into the phase III setting

    Expressive and receptive use of speech and graphic symbols by typically developing children: What skills contribute to performance on structured sentence-level tasks?

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    Purpose: To explore expressive and receptive use of speech and graphic symbols and relationships with linguistic and cognitive skills in children with typical development. Method: Participants were 82 children with typical development (4 to 9 years). Measures of memory, visual analysis skills, and receptive language were used, along with five experimental tasks with speech or symbols as input (stimulus) or output (response), using single clause and compound clause stimuli. Cluster analysis grouped participants with similar performances patterns, who were then compared on linguistic and cognitive skill measures. Result: The lowest performing group sometimes accurately interpreted graphic symbol utterances that were visible during responding. The mid-performing group was stronger on expressive than receptive symbol utterances when the model did not remain visible. The highest group was comparable on expressive and receptive symbol tasks, but nonetheless stronger with spoken utterances. Relationships of linguistic and cognitive skills with task performance differed across the clusters. Conclusion: The findings help clarify the input-output modality asymmetry in graphic symbol communication. Spoken language proficiency does not directly transfer to sentence-level expressive and receptive graphic symbol use. Exploring potentially challenging sentence-level phenomena is important. Research is warranted to explore developmental progressions and potential clinical applications more systematically
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