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111.
Feriel S. Hamdi Olivier Fran?ais Frederic Subra Elisabeth Dufour-Gergam Bruno Le Pioufle 《Biomicrofluidics》2013,7(4)
Cell fusion consists of inducing the formation of a hybridoma cell containing the genetic properties of the progenitor cells. Such an operation is usually performed chemically or electrically. The latter method, named electrofusion, is considered as having a strong potential, due to its efficiency and non-toxicity, but deserves further investigations prior to being applicable for key applications like antibody production and cancer immunotherapy. Indeed, to envision such applications, a high amount of hybrid cells is needed. In this context, we present in this paper a device for massive cell pairing and electrofusion, using a microarray of non-connected conductive pads. The electrofusion chamber––or channel––exposes cells to an inhomogeneous electric field, caused by the pads array, enabling the trapping and pairing of cells with dielectrophoresis (DEP) forces prior to electrofusion. Compared to a mechanical trapping, such electric trapping is fully reversible (on/off handling). The DEP force is contactless and thus eases the release of the produced hybridoma. Moreover, the absence of wire connections on the pads permits the high density trapping and electrofusion of cells. In this paper, the electric field mapping, the effect of metallic pads thickness, and the transmembrane potential of cells are studied based on a numerical model to optimize the device. Electric calculations and experiments were conducted to evaluate the trapping force. The structure was finally validated for cell pairing and electrofusion of arrays of cells. We believe that our approach of fully electric trapping with a simple structure is a promising method for massive production of electrofused hybridoma. 相似文献
112.
Joanne Elisabeth Edmondston Renato Schibeci 《International Journal of Science Education》2013,35(18):2451-2474
Despite rapid growth of the biotechnology industry worldwide, a number of public concerns about the application of biotechnology and its regulation remain. In response to these concerns, greater emphasis has been placed on promoting biotechnologists’ public engagement. As tertiary science degree programmes form the foundation of the biotechnology sector by providing a pipeline of university graduates entering into the profession, it has been proposed that formal science communication training be introduced at this early stage of career development. The aim of the present study was to examine the views of biotechnology students towards science communication and science communication training. Using an Australian biotechnology degree programme as a case study, 69 undergraduates from all three years of the programme were administered a questionnaire that asked them to rank the importance of 12 components of a biotechnology curriculum, including two science communication items. The results were compared to the responses of 274 students enrolled in other science programmes. Additional questions were provided to the second year biotechnology undergraduates and semi‐structured interviews were undertaken with 13 of these students to further examine their views of this area. The results of this study suggest that the biotechnology students surveyed do not value communication with non‐scientists nor science communication training. The implications of these findings for the reform of undergraduate biotechnology courses yet to integrate science communication training into their science curriculum are discussed. 相似文献
113.
114.
A new method of surface modification is described for enabling the in situ formation of homogenous porous polymer monoliths (PPMs) within poly(dimethylsiloxane) (PDMS) microfluidic channels that uses 365 nm UV illumination for polymerization. Porous polymer monolith formation in PDMS can be challenging because PDMS readily absorbs the monomers and solvents, changing the final monolith morphology, and because PDMS absorbs oxygen, which inhibits free-radical polymerization. The new approach is based on sequentially absorbing a non-hydrogen-abstracting photoinitiator and the monomers methyl methacrylate and ethylene diacrylate within the walls of the microchannel, and then polymerizing the surface treatment polymer within the PDMS, entangled with it but not covalently bound. Four different monolith compositions were tested, all of which yielded monoliths that were securely anchored and could withstand pressures exceeding the bonding strength of PDMS (40 psi) without dislodging. One was a recipe that was optimized to give a larger average pore size, required for low back pressure. This monolith was used to concentrate and subsequently mechanical lyse B lymphocytes. 相似文献
115.
116.
Uwe Engel Elisabeth Nordlohne Klaus Hurrelmann Birgit Holler 《European Journal of Psychology of Education - EJPE》1987,2(4):365-374
In modern, competitive societies the social organisation of «youth» implies both the chance and risk of (intergenerational) vertical social mobility. It is suggested that it is precisely this basic feature that to a considerable extent gives rise to substance use. In particular the paper aims at analysing the impact of the risk of educational downward mobility as well as some related characteristics. Using LISREL VI, it is shown that this type of educational career pattern, actual or anticipated, substantially contributes to the consumption of legal drugs. Weight is given to an extended analysis of the mode of action involved in the relationship between substance use and the career pattern as well as associated characteristics, respectively. As far as home is concerned, social conflict and associated feelings on the side of the adolescents turn out to be a major ‘mechanism’ through which the observable impact of educational downward mobility can be traced back. Integration into both the cultural system of «legalized» drug use and subcultural contexts as provided by social cliques is a further condition that strongly influences substance use among adolescents. 相似文献
117.
‘We did see the lapwing’ – practising environmental citizenship in upper-secondary science education
This article explores factors that promote the practice of environmental citizenship in science education and aims to contribute to the development of the concept of practising environmental citizenship. We follow six Norwegian secondary students (aged 16–17) participating in a small-scale intervention study conducting an assignment on a socioscientific issue (SSI) in their local district. Our findings reveal that dealing with an SSI in real-world settings through out-of-school activities set in the students’ local district is important for practising environmental citizenship. This article also addresses the tensions between the practice of environmental citizenship and the cultural issues related to school science. Our findings reveal that tensions exist between working with ready-made-science, as students normally do, to deal with science-in-the-making through an SSI. This research discuss the practical implications of the concept of practising environmental citizenship in science. 相似文献
118.
Ann Elisabeth Gunnulfsen 《Journal of Educational Change》2017,18(4):495-519
Studies have shown that school leaders are important in work with large-scale policy reforms in schools. However, the issue of how school leaders and teachers discuss and enact policy is under-studied. This article explores the discursive processes in school leaders’ and teachers’ policy enactment as they construct responses to policy. The data consists of video recordings and observation of leadership meetings and teacher-team meetings. A critical discourse analytical approach combined with perspectives of policy enactment as a process of interpretation serve as analytical concepts. The findings indicate the school leaders act more as narrators and enthusiasts, while the deputy managers and teacher-team leaders are more messengers and enforcers. The teachers mostly keep the discursive role as critics and preventers of ‘overburdening.’ A main argument is that the policy expectation of using national test results as a tool to develop school quality and student learning seems to be lost in translation. 相似文献
119.
AbstractThis study investigated university teachers’ characteristics and their influence on teaching practices: Coming from expectancy-value theory, teachers’ personal value of teaching was introduced as a possibly relevant variable and examined along with constructivist and transmissive teaching beliefs as to how they affect various aspects of university teaching. The sample consisted of 79 university teachers, whose data were combined with the teaching assessment of 2552 students enrolled in their courses and of external observers. Multiple regression analyses showed that value of teaching affected observed structuring, student active involvement, and rapport. Transmissive beliefs impacted the observed quality of instruction, and constructivist beliefs were positively related to student-reported clarity of instruction, the stimulation of student involvement, and rapport. Notably, the predictors displayed a data source specific result pattern. As potential reasons for the link between student-reported variables and constructivist beliefs a general factor in the students’ assessment and a survivor bias associated with teachers’ constructivist beliefs are discussed. 相似文献
120.