1,721,019 research outputs found
Radiotherapy of liver malignancies: from whole liver irradiation to stereotactic hypofractionated radiotherapy
No full textUntil recently radiotherapy of hepatic malignancies has played a limited role due to the well-known limited radiotolerance of the liver. The aim of this paper is to review the available data on the risk of radiation-induced liver disease (RILD) and to define the modern role of radiotherapy in the management of patients with metastatic or primary liver malignancies.
METHODS:
The advent of three-dimensional conformal treatment planning with dose-volume histogram analysis has made the study of partial liver irradiation possible. Limited portions of the liver may withstand high doses of radiation with minimal risk of RILD. Patients with solitary unresectable liver tumors may be treated with high-dose radiotherapy with curative intent. Recently, the feasibility of stereotactically guided treatment techniques with a single fraction or few treatment sessions has been explored in numerous institutions.
RESULTS:
The radiation tolerance of the whole liver found by several investigations is in the order of approximately 30 Gy, which seriously restricts its clinical application. The role of whole liver irradiation therefore appears of limited benefit in the palliation of patients with multiple liver metastases. The use of three-dimensional conformal techniques has made partial liver irradiation possible to doses in the 70-80 Gy range with conventional fractionation. At least two published series have reported improved local control and survival rates with dose escalation with three-dimensional conformal radiotherapy in patients with unresectable liver metastases. Similar outcomes have been recently reported with single dose (or hypofractionated) stereotactic radiotherapy both in metastatic and primary hepatic malignancies with minimal morbidity. Accurate target delineation and treatment reproducibility are the key to the success of this novel treatment approach, and specific treatment planning techniques and patient setup procedures must be developed to implement it.
CONCLUSIONS:
Stereotactic high-dose radiotherapy is technically feasible for the treatment of inoperable liver malignancies, with the potential of high local control and low morbidity. Definitive evidence on the clinical advantages of this technique over other more established treatments can only be gathered from well-designed clinical studie
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
Video evaluation of kinematics and dynamics of the beating cardiac syncytium: an alternative to the Langendorff's method
No full textMany important observations and discoveries in heart physiology have been made possible using the isolated heart method of Langendorff. Nevertheless, the Langendorff’s method has some limitations and disadvantages such as the vulnerability of the excised heart to contusions and injuries, the probability of preconditioning during instrumentation, the possibility to induce tissue oedema, and a high oxidative stress, leading to the deterioration of the contractile function. To avoid the preceding drawbacks associated to the use of a whole heart, we have alternatively used beating mouse cardiac syncytia cultured in vitro in order to assess possible ergotropic, chronotropic, and inotropic effects of drugs.
To achieve the preceding aim, we have developed a method based on image processing analysis to evaluate the kinematics and the dynamics of that drug-stimulated beating syncytia starting from the video registration of their contraction movement. In this manner, in comparison with the physiological no-drug condition, we have observed progressive positive ergotropic, positive chronotropic, and positive inotropic effects of 10 microM isoproterenol (beta-adrenergic agonist) and early positive ergotropic, negative chronotropic, and positive inotropic effects of 10 microM phenylephrine (alpha-adrenergic agonist), followed by a late phase with negative ergotropic, positive chronotropic, and negative inotropic trends.
The present method permitted a systematic study of in vitro beating syncytia, producing results coherent with previous works. As consequence, it could be used in in vitro studies of beating cardiac patches, as alternative to the Langendorff’s heart in biochemical and pharmacological studies, and, especially, when the Langendorff’s technique is inapplicable (e.g., in studies about human cardiac syncytium in physiological and pathological conditions, patient-tailored therapeutics, and syncytium models derived from induced pluripotent/embryonic stem cells with genetic mutations).
Furthermore, the method could help, in heart tissue engineering and bioartificial heart researches, to “engineer the heart piece by piece”. In particular, the proposed method could be useful in the identification of a suitable cell source, in the development and test of “smart” biomaterials, and in the design and use of novel bioreactors and microperfusion systems
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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