2,396 research outputs found
The influencing mechanism of manufacturing scene change on process domain knowledge reuse
It is necessary for a enterprise to reuse outside process domain knowledge to develop intelligent manufacturing technology. The key factors influencing knowledge reuse in digital manufacturing scene are manufacturing activities and PPR (Products, Processes and Resources) related to knowledge modeling, enterprise and integrated systems related to knowledge utilizing. How these factors influence knowledge modeling and utilizing is analyzed. Process domain knowledge reuse across the enterprises consists of knowledge reconfiguration and integrated application with CAx systems. The module-based knowledge model and loosely-coupled integration application of process domain knowledge are proposed. The aircraft sheet metal process domain knowledge reuse is taken as an example, and it shows that the knowledge reuse process can be made flexible and rapid
Comparison of personal narrative telling and fiction retelling in pre-school children using story grammar analysis
Thesis (B.Sc)--University of Hong Kong, 2010.Includes bibliographical references (p. 26-28)."A dissertation submitted in partial fulfillment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2010."Aim: This study compared the fiction retelling and personal narrative telling in assessing
pre-school childrenâs narrative skills in term of macrostructure.
Method: A total of 90 Cantonese-speaking pre-school children aged 3;0 to 6;0 were recruited.
Fiction narratives were elicited through retelling with a wordless story book after listened to a
model story. Personal narratives were prompted by conversational techniques. Samples were
analyzed by story grammar analysis.
Results: Fiction retelling scores showed better age differentiation in the number of story
grammar elements, higher reliability and stronger correlation with age and another language
measure. The development of story grammar elements was also described.
Conclusions: Fiction retelling was the more sensitive and reliable way to assess
Cantonese-speaking pre-school childrenâs narrative skills. With the standardized procedures
developed in this study, it is feasible to norm the materials and procedures onto a large group
of children for developing a standardized assessment for clinical use.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science
Post-Cyclization Skeletal Rearrangements in Plant Triterpenoid Biosynthesis by a Pair of Branchpoint Isomerases
Triterpenoids possess potent biological activities, but their polycyclic skeletons are challenging to synthesize. The skeletal diversity of triterpenoids in plants is generated by oxidosqualene cyclases based on epoxide-triggered cationic rearrangement cascades. Normally, triterpenoid skeletons then remain unaltered during subsequent tailoring steps. In contrast, the highly modified triterpenoids found in Sapindales plants imply the existence of post-cyclization skeletal rearrangement enzymes that have not yet been found. We report here a biosynthetic pathway in Sapindales plants for the modification of already cyclized tirucallane triterpenoids, controlling the pathway bifurcation between different plant triterpenoid classes. Using a combination of bioinformatics, heterologous expression in plants and chemical analyses, we identified a cytochrome P450 monooxygenase and two isomerases which harness the epoxidation-rearrangement biosynthetic logic of triterpene cyclizations for modifying the tirucallane scaffold. The two isomerases share the same epoxide substrate made by the cytochrome P450 monooxygenase CYP88A154, but generate two different rearrangement products, one containing a cyclopropane ring. Our findings reveal a process for skeletal rearrangements of triterpenoids in nature that expands their scaffold diversity after the initial cyclization. In addition, the enzymes described here are crucial for the biotechnological production of limonoid, quassinoid, apoprotolimonoid, and glabretane triterpenoids
Redditors Revealed: Motivational Factors of the Reddit Community
The purpose of this paper is to examine what motivational factors influence frequency of participation on the social news website Reddit.com, which has evolved from a news aggregator into a thriving virtual community. This study takes the uses and gratifications approach to examine why people participate in this community. A survey was posted to Reddit.com and was completed by 549 users. Multiple Regression analysis was conducted to assess factors (informativeness, socializing/ community building, status-seeking, entertainment) that influence participation. \ \ Findings indicate that uses and gratifications is a valid means by which to examine the motivations and gratification for users of new media, specifically online social media platforms. Findings for motivational factors were consistent with the current literature, with the exception of information seeking as a gratification sought / obtained. Results may be useful for designers of online communities and for scholars to further explore new types of needs and gratifications for those who participate in virtual communities
Identification of early quassinoid biosynthesis in the invasive tree of heaven (Ailanthus altissima) confirms evolutionary origin from protolimonoids
The tree of heaven, Ailanthus altissima (MILL.) SWINGLE, is a globally invasive plant known to secrete allelopathic metabolites called quassinoids. Quassinoids are highly modified triterpenoids. So far, nothing has been known about the biochemical basis of quassinoid biosynthesis. Here, based on transcriptome and metabolome data of Ailanthus altissima, we present the first three steps of quassinoid biosynthesis, which are catalysed by an oxidosqualene cyclase and two cytochrome P450 monooxygenases, resulting in the formation of the protolimonoid melianol. Strikingly, these steps are identical to the first steps of the biosynthesis of limonoids, structurally different triterpenoids from sister plant families within the same order Sapindales. Our results are therefore not only important to fully understand the biosynthesis of complex triterpenoids in plants, but also confirm the long-standing hypothesis that quassinoids and limonoids share an evolutionary origin. In addition, our transcriptome data for Ailanthus altissima will be beneficial to other researchers investigating the physiology and ecology of this invasive tree
3Dâprinted autoclavable plant holders to facilitate largeâscale protein production in plants
The Australian tobacco plant Nicotiana benthamiana is becoming increasingly popular as a platform for protein production and metabolic engineering. In this system, gene expression is achieved transiently by infiltrating N. benthamiana plants with suspensions of Agrobacterium tumefaciens carrying vectors with the target genes. To infiltrate larger numbers of plants, vacuum infiltration is the most efficient approach known, which is already used on industrial scale. Current laboratoryâscale solutions for vacuum infiltration, however, either require expensive customâtailored equipment or produce large amounts of biologically contaminated waste. To overcome these problems and lower the burden to establish vacuum infiltration in new laboratories, we present here 3Dâprinted plant holders for vacuum infiltration. We demonstrate that our plant holders are simple to use and enable a throughput of around 40 plants per hour. In addition, our 3Dâprinted plant holders are made from autoclavable material, which tolerate at least 12 autoclave cycles, helping to limit the production of contaminated waste and thus contributing to increased sustainability in research. In conclusion, our plant holders provide a simple, robust, safe and transparent platform for laboratoryâscale vacuum infiltration that can be readily adopted by new laboratories interested in protein and metabolite production in Nicotiana benthamiana. Practical application Transient expression in Nicotiana benthamiana provides a popular and rapid system for producing proteins in a plant host. To infiltrate larger numbers of plants (typically >20), vacuum infiltration is the method of choice. However, no system has been described so far which is robust to use and can be used without expensive and complex equipment. Our autoclavable 3Dâprinted plant holders presented here will greatly reduce the efforts required to adopt the vacuum infiltration technique in new laboratories. They are easy to use and can be autoclaved at least 12 times, which contributes to waste reduction and sustainability in research laboratories. We anticipate that the 3D printing design provided here will drastically lower the bar for new groups to employ vacuum infiltration for producing proteins and metabolites in Nicotiana benthamiana
3D-printed autoclavable plant holders to facilitate large-scale protein production in plants
The Australian tobacco plant Nicotiana benthamiana is becoming increasingly popular as a platform for protein production and metabolic engineering. In this system, gene expression is achieved transiently by infiltrating N. benthamiana plants with suspensions of Agrobacterium tumefaciens carrying vectors with the target genes. To infiltrate larger numbers of plants, vacuum infiltration is the most efficient approach known, which is already used on industrial scale. Current laboratory-scale solutions for vacuum infiltration, however, either require expensive custom-tailored equipment or produce large amounts of biologically contaminated waste. To overcome these problems and lower the burden to establish vacuum infiltration in new laboratories, we present here 3D-printed plant holders for vacuum infiltration. We demonstrate that our plant holders are simple to use and enable a throughput of around 40 plants per hour. In addition, our 3D-printed plant holders are made from autoclavable material, which tolerate at least 12 autoclave cycles, helping to limit the production of contaminated waste and thus contributing to increased sustainability in research. In conclusion, our plant holders provide a simple, robust, safe and transparent platform for laboratory-scale vacuum infiltration that can be readily adopted by new laboratories interested in protein and metabolite production in Nicotiana benthamiana. Practical application. Transient expression in Nicotiana benthamiana provides a popular and rapid system for producing proteins in a plant host. To infiltrate larger numbers of plants (typically >20), vacuum infiltration is the method of choice. However, no system has been described so far which is robust to use and can be used without expensive and complex equipment. Our autoclavable 3D-printed plant holders presented here will greatly reduce the efforts required to adopt the vacuum infiltration technique in new laboratories. They are easy to use and can be autoclaved at least 12 times, which contributes to waste reduction and sustainability in research laboratories. We anticipate that the 3D printing design provided here will drastically lower the bar for new groups to employ vacuum infiltration for producing proteins and metabolites in Nicotiana benthamiana
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