958 resultados para 090404 Membrane and Separation Technologies


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Discourse and Creativity examines the way different approaches to discourse analysis conceptualize the notion of creativity and address it analytically. It includes examples of studies of creativity from a variety of traditions and examines the following key areas, how people interpret and use discourse, the processes and practices of discourse production, discourse in modes other than written and spoken language, and the relationship between discourse and the technologies used to produce it.

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Urea is an important nitrogen source for some bromeliad species, and in nature it is derived from the excretion of amphibians, which visit or live inside the tank water. Its assimilation is dependent on the hydrolysis by urease (EC: 3.5.1.5), and although this enzyme has been extensively studied to date, little information is available about its cellular location. In higher plants, this enzyme is considered to be present in the cytoplasm. However, there is evidence that urease is secreted by the bromeliad Vriesea gigantea, implying that this enzyme is at least temporarily located in the plasmatic membrane and cell wall. In this article, urease activity was measured in different cell fractions using leaf tissues of two bromeliad species: the tank bromeliad V. gigantea and the terrestrial bromeliad Ananas comosus (L.) Merr. In both species, urease was present in the cell wall and membrane fractions, besides the cytoplasm. Moreover, a considerable difference was observed between the species: while V. gigantea had 40% of the urease activity detected in the membranes and cell wall fractions, less than 20% were found in the same fractions in A. comosus. The high proportion of urease found in cell wall and membranes in V. gigantea was also investigated by cytochemical detection and immunoreaction assay. Both approaches confirmed the enzymatic assay. We suggest this physiological characteristic allows tank bromeliads to survive in a nitrogen-limited environment, utilizing urea rapidly and efficiently and competing successfully for this nitrogen source against microorganisms that live in the tank water.

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Endostatin (ES) is a potent inhibitor of angiogenesis and tumor growth. Continuous ES delivery of ES improves the efficacy and potency of the antitumoral therapy. The TheraCyte (R) system is a polytetrafluoroethylene (PTFE) semipermeable membrane macroencapsulation system for implantation of genetically engineered cells specially designed for the in vivo delivery of therapeutic proteins, such as ES, which circumvents the problem of limited half-life and variation in circulating levels. In order to enable neovascularization at the tissues adjacent to the devices prior to ES secretion by the cells inside them, we designed a scheme in which empty TheraCyte (R) devices were preimplanted SC into immunodeficient mice. Only after healing (17 days later) were Chinese hamster ovary cells expressing ES injected into the preimplanted devices. In another model for device implantation, the cells expressing ES where loaded into the immunoisolation devices prior to implantation into the animals, and the TheraCyte (R) were then immediately implanted SC into the mice. Throughout the 2-month study, constant high ES levels of up to 3.7 mu g/ml were detected in the plasma of the mice preimplanted with the devices, while lower but also constant levels of ES (up to 2.1 mu g/ml plasma) were detected in the mice that had received devices preloaded with the ES-expressing cells. Immunohistochemistry using anti-ES antibody showed reaction within the device and outside it, demonstrating that ES, secreted by the confined recombinant cells, permeated through the membrane and reached the surrounding tissues.

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Point placement strategies aim at mapping data points represented in higher dimensions to bi-dimensional spaces and are frequently used to visualize relationships amongst data instances. They have been valuable tools for analysis and exploration of data sets of various kinds. Many conventional techniques, however, do not behave well when the number of dimensions is high, such as in the case of documents collections. Later approaches handle that shortcoming, but may cause too much clutter to allow flexible exploration to take place. In this work we present a novel hierarchical point placement technique that is capable of dealing with these problems. While good grouping and separation of data with high similarity is maintained without increasing computation cost, its hierarchical structure lends itself both to exploration in various levels of detail and to handling data in subsets, improving analysis capability and also allowing manipulation of larger data sets.

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Photodynamic therapy, used mainly for cancer treatment and microorganisms inaction, is based on production of reactive oxygen species by light irradiation of a sensitizer. Hematoporphyrin derivatives as Photofrin (R) (PF) Photogem (R) (PG) and Photosan (R) (PF), and chlorin-c6-derivatives as Photodithazine (R)(PZ), have suitable sensitizing properties. The present study provides a way to make a fast previous evaluation of photosensitizers efficacy by a combination of techniques: a) use of brovine serum albumin and uric acid as chemical dosimeters; b) photo-hemolysis of red blood cells used as a cell membrane interaction model, and c) octanol/phosphate buffer partition to assess the relative lipophilicity of the compounds. The results suggest the photodynamic efficient rankings PZ > PG >= PF > PS. These results agree with the cytotoxicity of the photosensitizers as well as to chromatographic separation of the HpDs, both performed in our group, showing that the more lipophilic is the dye, the more acute is the damage to the RBC membrane and the oxidation of indol, which is immersed in the hydrophobic region of albumin.

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While there is research supporting the use of technology in classrooms, there is also evidence that technology often disrupts student learning. Examples of technology use in classrooms by both teachers and students will be explored, including the benefits and risks of each to the learning process. Research findings on cognition, attention, and classroom technologies will inform strategies for best practices for classroom technology use.

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In the field of Information and Communication Technologies for Development (ICT4D) ICT use in education is well studied. Education is often seen as a pre-requisite for development and ICTs are believed to aid in education, e.g. to make it more accessible and to increase its quality. In this paper we study the access and use of ICT in a study circle (SC) education program in the south coast of Kenya. The study is qualitative reporting results based on interviews and observations with SC participants, government officers and SC coordinators and teachers. The study builds on the capability approach perspective of development where individuals’ opportunities and ability to live a life that they value are focused. The aim of the study is to investigate the capability outcomes enabled through the capability inputs access and use of ICT in education as well as the factors that enabled and/or restricted the outcomes. Findings show that many opportunities have been enabled such as an increase in the ability to generate an income, learning benefits, community development and basic human development (e.g. literacy and self-confidence). However, conversion factors such as a poorly developed infrastructure and poor IT literacy prevent many of the individuals from taking full advantage of the ICT and the opportunities it enables. 

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Schools appear in some accounts of community informatics as part of community, one of a number of organisations that need to be taken into account, perhaps on the basis of them being useful physical or human resources around which community informatics might be based. For their part, schools, at least in Australia, have been an important, early element in the broad take-up of computing and communication technologies (CCTs) by the community. Apart from the possibility of using school resources to support community access out of school time and based on what is published in both fields, schools and work in community informatics have tended to operate independently of one another. There are, nonetheless, interesting parallels in these two broad areas of activity which promote the use of CCTs. This chapter outlines a new research agenda in which schools produce knowledge for local community and in doing so develop new and productive community partnerships. The development provides interesting opportunities for the transformation of regions via this approach to community informatics. The background to this project is based in the long history of using CCTs in schools. The chapter will argue that the way in which schools understand CCTs is crucial to shaping what is possible to be done with CCTs in schools. Shifting the emphasis from information to relationships opens up alternatives that provide opportunities for significant, new relationships with community.

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Deakin University, Australia, has committed resources over a number of years to developing the use of information and communication technologies in all aspects of teaching and learning. This paper focuses on the development over a four year period of an Asynchronous Learning Network (ALN) for distance education students studying undergraduate introductory macroeconomics. The research is based on quantitative and qualitative data gained from student evaluations, academic staff interviews, participation levels and an analysis of the online communication. Key findings from the research relate to the quality of the learning environment, the level of communication, and the role of academic staff in the learning experience. Strategies discussed for the successful use of an ALN include the nurturing of a collaborative learning environment, the adaptation of curriculum and pedagogy, the role of assessment, and the role of academic staff training and development.

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There has been less than a decade of rapid diffusion of the Internet and related technologies into the commercial world, with resultant changes in business processes, business structure and financial valuations of adopting businesses. Advocates and critics of new online business models are still addressing the relationship between online or electronic marketing using the Internet (Net) and marketing and financial outcomes. There remains a need for empirical research into specific aspects of online marketing strategy beyond click-through analysis, Web audience analysis and scrutiny of website properties to mention the most widely examined elements. This paper discusses conceptualizations underpinning development of a model of Web use in marketing strategy. The aim of the paper is to aid both business practitioner and academician alike in connecting direct and online marketing using the Web with performance outcomes

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Increased hepatic glucose output and decreased glucose utilization are implicated in the development of type 2 diabetes. We previously reported that the expression of a novel gene, Tanis, was upregulated in the liver during fasting in the obese/diabetic animal model Psammomys obesus. Here, we have further studied the protein and its function. Cell fractionation indicated that Tanis was localized in the plasma membrane and microsomes but not in the nucleus, mitochondria, or soluble protein fraction. Consistent with previous gene expression data, hepatic Tanis protein levels increased more significantly in diabetic P. obesus than in nondiabetic controls after fasting. We used a recombinant adenovirus to increase Tanis expression in hepatoma H4IIE cells and investigated its role in metabolism. Tanis overexpression reduced glucose uptake, basal and insulin-stimulated glycogen synthesis, and glycogen content and attenuated the suppression of PEPCK gene expression by insulin, but it did not affect insulin-stimulated insulin receptor phosphorylation or triglyceride synthesis. These results suggest that Tanis may be involved in the regulation of glucose metabolism, and increased expression of Tanis could contribute to insulin resistance in the liver.

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This article examines information and communication technologies(ICTs) practices in the home and school settings of four disadvantaged families. It reports the findings of a year-long study that investigated the nexus between computer-mediated literacy practices at home and at school and whether this inter-connectivity could make a difference in school success. The findings indicate that there was disjunction between home and school use. The ``digital divide'' exists for the families of this study, not in terms of access but in the gap between ICT practices at home and school. Schools in this study did not integrate ICT skills learned and demonstratedin the home environment into ICT practices at school. The study concludes that constructing pedagogical connections between home and school ICT practices may begin to bridge the ``digital divide''.

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To have an effective and efficient mechanism to store, manage and utilize software sources is essential to the automation of software engineering. The paper presents an innovative approach in managing software resources using software warehouse where software assets are systematically accumulated, deposited, retrieved, packaged, managed and utilized, driven by data-mining and OLAP technologies. The results lead to streamlined high efficient software development process and enhance the productivity in response to modern challenges of the design and development of software applications.

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While there has been widespread take-up of the concept 'flexible learning' within various educational environments—and equally frequent references to the flexible 'natures' of the computer and communication technologies that often underpin flexible learning initiatives—the relationship between technologies and flexibility is not a simple one. In this paper we examine some of the more persistent myths about technologies that are intertwined with discourses of flexibility. We highlight some of the more common 'muddles' that these myths can lead us in to and argue that the 'mess' that so often results from well-intentioned moves to 'be more flexible' is largely a result of the ways that CCTs, or indeed any new educational technology or strategy, is theorized. Drawing on a recent study of online teaching and learning in higher education, we outline a new framework for examining these and related issues as they apply to teacher education.

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New demographic patterns as well as new communication and information technologies and administrative and marketing practices have irrevocably altered schools in Australia's large cities. This study examines the ways that teachers and parents in one urban school speak about race and ethnicity in the midst of these changes. Beneath the ironic relationship between difference and sameness which underpins multicultural debate are different understandings that determine ways some belong and some do not belong within the school community. This paradoxical relationship persists, despite increasingly post-modern definitions of identity that underpin the field of this debate. I conclude that the examination of multicultural curricula must include the normalized ways of knowing and 'being' identity, which underpin conversations about race and identity.