1,721,323 research outputs found
Beta-hydroxy-betamethylbutyrate (HMB) and sarcopenia
No full textBeta‐hydroxy‐beta‐methylbutyrate (HMB) is an active metabolite of leucine, a branched‐chain essential amino acid entirely derived from food sources, and it has been studied for many decades (Figure 24.1). HMB per se is present in very small amounts of some foods, such as cauliflower, citrus fruit, avocado, and catfish. HMB is synthesized from leucine in two separate steps occurring in liver and muscle cell [1]. At muscle cells level, leucine has an explicit role in controlling and at the same time regulating protein synthesis, and HMB has an important role as a key active metabolite in this process. Nevertheless, only approximately 5% of leucine that we can eat with the usual diet is converted to HMB, which, in a subject weighing 70–80 kg, ends in the production of 0.2–0.4 g of HMB per day [2]
Biomarkers for Physical Frailty and Sarcopenia: A “Two-Body Problem”
No full textThis chapter presents multi-marker biomarker discovery as an approach for capturing the complexity of physical frailty and sarcopenia (PFandS), overviews candidate biomarkers for PFandS, and discusses relevant pathways involving these mediators. PFandS has a multifactorial etiology that recapitulates all biological hallmarks of aging. Multi-marker analysis has increasingly been recognized as a complementary and more sophisticated strategy for investigating highly dynamic and complex conditions, including PFandS. The development of biological markers that can be measured in biofluids at any time point and be used in a cost-effective manner to guide the diagnosis and facilitate the monitoring of PFandS are highly sought after. The assessment of clinical, functional, and imaging parameters was used for identifying PFandS. Although paving the way for biomarker discovery, all the reported studies have the caveat of investigating single domains of the PFandS condition
Antiageing strategies
No full textThe certainty of ageing and death has been a major concern of humans since the beginnings of time, with a consequent never-ending search for methods to combat the consequences of the ageing process and delay the final moment as long as possible. This chapter explores the topic of antiageing therapies from different perspectives. It discusses the rationale behind the possible delay of death, disease, and disability. Then, some of the advances in biogerontological research in animal models and possible translations into humans are explored. The chapter examines the results of epidemiological studies on lifestyle modification proven to be effective in promoting healthy ageing. Disability and functional dependence associated with ageing may be reversible to some extent; however, when the functional reserve becomes extremely depleted, the restoration of normal function is no longer possible
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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