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Variable density randomized stack of spirals (VDR-SoS) for compressive sensing MRI
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Technological innovations in magnetic resonance for early detection of cardiovascular diseases
Full text linkMost recent technical innovations in cardiovascular MR imaging (CMRI) are presented in this review. They include hardware and software developments, and novelties in parametric mapping. All these recent improvements lead to high spatial and temporal resolution and quantitative information on the heart structure and function. They make it achievable ambitious goals in the field of mapletic resonance, such as the early detection of cardiovascular pathologies.
In this review article, we present recent innovations in CMRI, emphasizing the progresses performed and the solutions proposed to some yet opened technical problems
CREPE: Mathematical model for crosstalking of endothelial cells and hepatocyte metabolism
Full text linkThe liver shows a close coexistence between endothelial cells and hepatocytes (HepG2). Endothelial cells' main purpose is to protect (HepG2) from blood vessel shear stress, acting as a barrier, but experimental evidence suggests that they could also play a role in regulating (HepG2) glucose metabolism. A well-known singular effect in hepatocyte-endothelial co-cultures is the reduction of glucose consumption respect to (HepG2) in single culture. (HepG2) were shown to reduce their glucose consumption supporting energy needs of endothelial cells. Monti have studied the effects of endothelin-1 (Et-1) on Glucokinase activity in adult rat (HepG2). They observed a reduction in hepatocytes Glucokinase catalytic rate, which is dependent on Et-1 concentration. We developed crosstalking of endothelial cells and hepatocyte metabolism (CREPE) that is a mathematical model of the endothelin-1 mediated crosstalk between HepG2 and endothelial cells (human umbilical vein endothelial cells) in a traditional static co-culture system. CREPE was validated against experimental data, showing good agreement with them
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
CREPE: A first mathematical model for crosstalking of endothelial cells and hepatocyte metabolism
No full textAccelerating 4D flow MRI by exploiting low-rank matrix structure and hadamard sparsity
No full textPurpose: To develop accelerated 4D flow MRI by exploiting low-rank matrix structure and Hadamard sparsity. Theory and Methods: 4D flow MRI data can be represented as the sum of a low-rank and a sparse component. To optimize the sparse representation of the data, it is proposed to incorporate a Hadamard transform of the velocity-encoding segments. Retrospectively and prospectively, undersampled data of the aorta of healthy subjects are used to assess the reconstruction accuracy of the proposed method relative to k-t SPARSE-SENSE reconstruction. Image reconstruction from eight-fold prospective undersampling is demonstrated and compared with conventional SENSE imaging. Results: Simulation results revealed consistently lower errors in velocity estimation when compared with k-t SPARSE-SENSE. In vivo data yielded reduced error of peak flow with the proposed method relative to k-t SPARSE-SENSE when compared with two-fold SENSE ( 2.5±4.6% versus 10.2±8.5% in the ascending aorta, 3.6±8.4% versus 9.2±9.0% in the descending aorta). Streamline visualization showed more consistent flow fields with the proposed technique relative to the benchmark methods. Conclusion: Image reconstruction by exploiting low-rank structure and Hadamard sparsity of 4D flow MRI data improves the reconstruction accuracy relative to current state-of-the-art methods and holds promise to reduce the long scan times of 4D flow MRI
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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