1,720,966 research outputs found
Muscle damage and adaptations induced by eccentric cycling in relation to extracellular matrix
No full textBoth the acute damage and resulting adaptations induced by eccentric exercise have been well documented, but less is known about their underpinning mechanisms. It is possible that muscle extracellular matrix (ECM), including both collagenous and costameric (e.g. integrins) components, plays a major role in both damage and adaptation, but this has not been extensively investigated. Eccentric cycling (ECC) was chosen as a model to investigate these mechanisms, since it consists only of eccentric muscle actions, and can induce typical characteristics of muscle damage such as prolonged decreases in muscle function and delayed onset muscle soreness (DOMS); while ECC training has been shown to induce increases in muscle function and muscle mass, even at low intensities. The purpose of this PhD project was to investigate the muscle damage and adaptations induced by the ECC in relation to collagen breakdown and integrin signalling pathways, which may shed light on the connection between ECM-mediated muscle changes.
This research project consisted of three studies. In Study 1, high- (HI) and low-intensity (LI) ECC with the same mechanical work were compared for changes in muscle function and DOMS, while the repeated bout effect was examined after subsequent HI ECC. Eleven men performed HI-ECC (1 min × 5 at 20% of peak power output: PPO) for two bouts separated by 2 weeks (H-H), and nine men performed LI-ECC (4 min × 5 at 5% PPO) for the first bout and then HI-ECC for the second bout (L-H). At 24 h after the first bout, both groups showed similar decreases in maximal isometric (70° knee angle, -10.6±11.8%) and isokinetic (-11.0±8.2%) knee extensor (KE) torque, and squat (-7.7±10.4%) and counter-movement (-5.9±8.4%) jump heights (P
In Study 2, plasma CK activity, hydroxyproline (Hyp) and cell-free DNA (cfDNA) concentrations were measured before, immediately after and 24 – 72 h after HI-ECC and LI-ECC, and examined in relation to changes in maximum voluntary isometric contraction strength (MVIC) and DOMS. The participants were the same as those in Study 1. Plasma CK activity increased at 24 h (135%), and Hyp concentration increased (40–53%, P
In Study 3, changes in the expression of integrin – integrin-linked kinase (ILK) – rapamycin-insensitive companion of mTOR (RICTOR) protein complex in VL before and after 8 weeks of HI-ECC training were examined along with possible associations to changes in muscle function and VL cross-sectional area (CSA) from pre- to post-training. Eleven young men completed 24 sessions of ECC with progressive increases in intensity and duration, resulting in a 2-fold increase in work from the first 3 sessions (75.4±14.1 kJ) to the last 3 sessions (150.7±28.4 kJ). Lower-limb lean mass (dual-energy X-ray absorptiometry), VL CSA (extended field-of-view ultrasonography), lower-limb static strength measured on the ergometer (breaking strength against the force provided by the crank pushing the foot), peak and average cycling power output were measured, and VL micro-biopsy samples were obtained before and after training. Significant (P
The findings from the three studies provide new insights into the mechanisms underlying muscle damage and adaptations induced by eccentric exercise. The Study 1 results showed that even low-intensity eccentric muscle actions affected the ECM, as indicated by DOMS, which has been shown by previous studies to be more associated with connective tissue damage and inflammation. ECC did not induce extensive muscle fibre damage, as indicated by the small increases in plasma CK activity. It is interesting that the increases in plasma Hyp concentration were similar between HI-ECC and LI-ECC, despite a significant difference in DOMS magnitude. ECC training increased integrin-ILK-RICTOR expression, but it was not associated with the increased CSA or muscle function. It seems possible that the ECM is involved in muscle damage and adaptations, but this was not endorsed by the present studies. It is necessary to investigate further histological changes in ECM after the initial and repeated bouts of eccentric exercise, how eccentric exercise induces ECM remodelling, and how this affects changes in muscle architecture including muscle CSA or mass and muscle function
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
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
Elastic tubes: The ideal equipment for telehealth exercise medicine in the management of prostate cancer?
Get PDFProstate cancer (PCa) affects 1 in 8 men, but exercise therapy has been shown to be a very effective intervention not only to induce physiological benefits but to also reduce the side effects of cancer treatments typically administered during PCa. The COVID19 pandemic has restricted access to exercise clinics, a problem which always existed for people living in rural and remote areas. This caused many exercise physiologists and researchers to transition their clinic-based exercise to online, home-based exercise. We would like to propose that researchers and exercise physiologists should consider the use of elastic tubes in both research and the clinical management of PCa, when exercise programs are administered remotely, as their characteristics make them an ideal exercise equipment. In this article, the characteristics, considerations, and information on quantifying exercise dosage when using elastic tubes in remote exercise delivery are discussed
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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