1,721,139 research outputs found
Chips & Tips: Rapid prototyping of a PMMA microfluidic chip with integrated platinum electrodes
No full textThis is a very quick and useful method for researchers who do not have access to high tech micro-fabrication facilities and want to try out an idea or a test in a quick, cheap and simple fashion. In this case it is for those of us who want to test certain techniques such as in-channel electrochemical, conductivity or impedance measurements. It also saves time and costs from using high tech fabrication techniques and will aid the researcher in future designs that can then be fabricated the more conventional way in a clean room. In addition, it is a cheap and effective way of introducing undergraduate and masters students to various chip technique
High flow rate microfluidic device for blood plasma separation using a range of temperatures
No full textA hybrid microfluidic device that uses hydrodynamic forces to separate human plasma from blood cells has been designed and fabricated and the advantageous effects of temperature and flow rates are investigated in this paper. The blood separating device includes an inlet which is reduced by approximately 20 times to a small constrictor channel, which then opens out to a larger output channel with a small lateral channel for the collection of plasma. When tested the device separated plasma from whole blood using a wide range of flow rates, between 50 µl min-1 and 200 µl min-1, at the higher flow rates injected by hand and at temperatures ranging from 23 °C to 50 °C, the latter resulting in an increase in the cell-free layer of up to 250%. It was also tested continuously using between 5% and 40% erythrocytes in plasma and whole blood without blocking the channels or hemolysis of the cells. The mean percentage of plasma collected after separation was 3.47% from a sample of 1 ml. The percentage of cells removed from the plasma varied depending on the flow rate used, but at 37 °C ranged between 95.4 ± 1% and 97.05 ± 05% at 100 µl min-1 and 200 µl min-1, respectively. The change in temperature also had an effect on the number of cells removed from the plasma which was between 93.5 ± 0.65% and 97.01 ± 0.3% at 26.9 °C and 37 °C, respectively, using a flow rate of 100 µl min-1. Due to its ability to operate in a wide range of conditions, it is envisaged that this device can be used in in vitrolab on a chip applications, as well as a hand-held point of care (POC) devic
Ressenyes
No full textIndex de les obres ressenyades: Josep OLIVERAS I SAMITIER, Desenvolupament industrial i evolució urbana a Manresa (1800-1870). OLIVERAS i Samitier, Josep. La consolidació de la ciutat industria
Ressenyes
No full textIndex de les obres ressenyades: Josep OLIVERAS I SAMITIER, Desenvolupament industrial i evolució urbana a Manresa (1800-1870). OLIVERAS i Samitier, Josep. La consolidació de la ciutat industria
Simplified microenvironments and reduced cell culture size influence the cell differentiation outcome in cellular microarrays
Full text linkCellular microarrays present a promising tool for multiplex evaluation of the signalling effect of substrate-immobilized factors on cellular differentiation. In this paper, we compare the early myoblast-to-osteoblast cell commitment steps in response to a growth factor stimulus using standard well plate differentiation assays or cellular microarrays. Our results show that restraints on the cell culture size, inherent to cellular microarrays, impair the differentiation outcome. Also, while cells growing on spots with immobilised BMP-2 are early biased towards the osteoblast fate, longer periods of cell culturing in the microarrays result in cell proliferation and blockage of osteoblast differentiation. The results presented here raise concerns about the efficiency of cell differentiation when the cell culture dimensions are reduced to a simplified microspot environment. Also, these results suggest that further efforts should be devoted to increasing the complexity of the microspots composition, aiming to replace signalling cues missing in this system.Fil: Rodríguez Seguí, Santiago Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Barcelona; EspañaFil: Ortuño, María José. Universitat Autònoma de Barcelona; EspañaFil: Ventura, Francesc. Universitat Autònoma de Barcelona; EspañaFil: Martinez, Elena. Universitat Autònoma de Barcelona; EspañaFil: Samitier, Josep. Universidad de Barcelona; Españ
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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