1,721,268 research outputs found
A perspective on DNA damage-induced potentiation of the pentose phosphate shunt and reductive stress in chemoresistance
No full textMetabolic rearrangements and genome instability are two hallmarks of cancer. Recent evidence from our laboratory demonstrates that persistent DNA lesions hampering transcription may cause glucose rerouting through the pentose phosphate shunt and reductive stress. Here, we highlight the relevance of these findings for cancer and chemoresistance development
Endocytic iron trafficking and mitochondria in Parkinson's disease
Get PDFParkinson's disease (PD) - the second most common neurodegenerative disorder - is a multifactorial disease, the causes of which should be sought in complex and detrimental interactions between genetic and environmental factors. Multiple lines of evidence, however, identify mitochondrial dysfunction, oxidative stress, and iron accumulation as central pathogenic mechanisms. These factors are closely intertwined because mitochondria are a major source of pro-oxidant species and are the major intracellular recipients of iron. How iron is transported to mitochondria, however, is largely unknown. Some studies suggest that trafficking through endocytosis may participate to mitochondrial iron delivery with a “kiss and run” mechanism. Intracellular transferrin levels increase in PD, possibly as a consequence of oxidation of iron-containing prosthetic groups in mitochondria. It is therefore conceivable that transferrin endocytic trafficking can contribute to noxious iron accumulation. This short review will summarize these findings and discuss their relevance for a better understanding of PD pathogenesis
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
Variations 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Reliability of three-dimensional photonic scanner anthropometry performed by skilled and naïve operators
No full textThis work explored the relative and absolute reliability of three-dimensional (3D) anthropometry performed by skilled and naïve operators using a fast, pose tolerant whole-body 3D scanner device. Upon skin landmarking by an experienced operator (skilled anthropometrist, SA), twelve subjects (six males and six females) underwent a thorough 3D anthropometric evaluation by the SA and two naïve operators (NA). Using the same landmarks, the SA also performed traditional anthropometry measurements. All measurements were taken twice. Relative reliability was tested with the Pearson's correlation coefficient r and the intraclass correlation coefficient (ICC); absolute reliability was tested calculating the percentage coefficient of variation (%CV), the standard error of measurement (SEM), the percentage technical error of measurement (%TEM), and paired Student's t test. Results showed that intra-operator relative and absolute reliability was excellent for all and most 3D measurement items, respectively, independently of the operator's skill. Inter-operator (SA vs. individual NA) relative reliability was excellent as well; inter-operator absolute reliability was not acceptable for about only 30% of measurement items. Results of this work show that 3D anthropometry has strong potential in anthropometry due to high intrinsic reliability and less need for operator training vs. traditional anthropometry
Synthesis and characterization of LaFeO3 powders prepared by a mixed mechanical/thermal processing route
No full textLanthanum ferrite, LaFeO3 (LF), has raised considerable interest since it can be used in many applications such as solid-oxide fuel cell electrode, sensor material (H2O and ethanol) and catalyst. Since the conventional ceramic route of synthesis has some disadvantages, mainly related to an exaggerated grain growth, LF has been prepared by different methods including combustion synthesis, sol–gel, hydrothermal processes, polymerizable complex method and mechanochemistry. As concerns this last method, a problem occurs due to the moisture sensitivity of La2O3. To overcome the problem, we used lanthanum acetate sesquihydrate [La(CH3COO)3·1.5H2O] and iron (II) oxalate dehydrate [FeC2O4·2H2O] as precursors. The mechanism of the solid-state reactions in the mixtures has been studied by TG–DSC and XRPD. Synthesis of LaFeO3 has been realized by annealing the mechanically activated mixtures for 3 h at temperatures between 500 and 800 °C. While LF prepared at 500 °C < T < 600 °C has an amorphous character, LF obtained at T ≥ 600 °C is free from carbonaceous impurities as it is shown by FT-IR and TG measurements. The specific area of the LaFeO3 powders obtained starting from the mechanically activated mixture is decreasing by increasing the annealing temperature. On the contrary, the annealing on samples of physical mixture at temperatures up to 800 °C only yields a mixture of LaFeO3, La2O3 and Fe2O3
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