1,721,040 research outputs found
Effect of low-frequency, low-amplitude magntic fields on the permeability of cationic liposomes entrapping carbonic anhydrase.I. Evidence for charged lipid involvement.
No full textThe influence of low frequency (4–16 Hz), low amplitude (25–75 μT) magnetic fields on the diffusion processes in enzyme-loaded unilamellar liposomes as bioreactors was studied. Cationic liposomes containing dipalmitoylphosphatidylcholine, cholesterol, and charged lipid stearylamine (SA) at different molar ratios (6:3:1 or 5:3:2) were used. Previous kinetic experiments showed a very low self-diffusion rate of the substrate p-nitrophenyl acetate (p-NPA) across intact liposome bilayer. After 60 min of exposure to 7 Hz sinusoidal (50 μT peak) and parallel static (50 μT) magnetic fields the enzyme activity, as a function of increased diffusion rate of p-NPA, rose from 17 ± 3% to 80 ± 9% (P < .0005, n = 15) in the 5:3:2 liposomes. This effect was dependent on the SA concentration in the liposomes. Only the presence of combined sinusoidal (AC) and static (DC) magnetic fields affected the p-NPA diffusion rates. No enzyme leakage was observed. Such studies suggest a plausible link between the action of extremely low frequency magnetic field on charged lipids and a change of membrane permeability
Identification of cardiac events by Optical Vibrocardiograpy: comparison with Phonocardiography
No full textA laser Doppler approach to cardiac motion monitoring: Effects of surface and measurement position
No full textIn this paper we present a novel, non-invasive measurement system for optical monitoring of the cardiac rate. This measurement method, called vibrocardiography (VCG), is based on the use of a laser Doppler vibrometer for the measurement of the velocity of displacement of the skin in correspondence of the chest wall. We report the typical VCG signals measured on 4 healthy subject and in particular, we investigated the effect on the signal of the measurement position respect to the chest wall as well as the effect of the surface characteristics on the measured signal
Dispositivo microfluidico di mescolamento convettivo
No full textL’invenzione consiste in un dispositivo atto a produrre mescolamento di fluidi su scala microscopica. Il dispositivo è caratterizzato da una geometria atta a promuovere la generazione di vortici che facilitano il mescolamento all’interno di un canale curvo in determinate condizioni di esercizio con una bassa perdita di carico.
Problema risolto: mescolamento convettivo passivo che favorisce reazioni chimiche a fronte di una bassa perdita di carico
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Synthetic 4D phase contrast MRI datasets: A CFD-based approach for the validation of advanced fluid dynamics calculations in vivo
No full textVariations on the Author
Get PDF“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
Get PDFWe 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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