1,720,955 research outputs found
Electromyographic evaluation of free divers wearing realaxing bite
No full textThe objective of the project was to detect possible variations of the masticator muscolar tension in free divers wearing relaxing bite. The study was carried out by means of EMG evaluations performed before and after the use of the relaxing bite in order to verify its effectiveness in this specific sport.
Materials and Methods - Four athletes were selected, two males and two females, of age between 23 and 39 with similar characteristics in terms of training typology and agonistic level.
After an initial EMG exam, each athlete was given a bite to be worn only at night for the first three months (8 hours), and during night time and during training sessions for the following three months (more than 8 hours). In order to quantify the changes of masseter and temporalis muscles tension, two more sessions of surface EMG recordings were made during the period of use of the bite on a three monthly basis. Each session consisted of three registrations, two of them were associated with maximum voluntary contraction and in rest position respectively, while the third one was made in free diving condition for a maximum amount of time of two minutes for each individual. The latter exam allows to assess the impact of the hypoxia on the muscular condition (as it actually occurs during a sport performance) as well as to evaluate the impact of the relaxing bite on the muscular condition in order to validate its use in this particular sport.
The EMG recordings were made according to the following scheme: in maximum voluntary contraction (the patient can breathe); in rest position (the patient can breathe); in free diving, emulation for a maximum amount of time of 2 minutes for each athlete. The second EMG recording (after three months of nightly bite application) and the third EMG recording (at the sixth month, after three months of bite application during night time and during sport trainings) were complemented with a fourth registration which was performed in apnea for a maximum amount of time of 2 minutes (as in the first test) while the athletics wearing the relaxing bite.
Conclusion - Despite the unavoidable limits of the investigation due to the small size of the sample considered (because of the difficulty of finding homogeneous free divers not affected by TMD), such exams will allow us to assess the variations of EMG potentials in free divers wearing relaxing bites during breath as well as during free diving dry runs. Moreover, the results will provide us a consistent starting point to understand whether the use of bites during sport activity may increase muscular relax in the cranium-facial district, thus inducing enhanced agonistic performance
Valutazione elettromiografica in atleti apneisti trattati con bite di rilassamento
No full textScopo - L' obiettivo di questo progetto di ricerca è stato quello di valutare un'eventuale variazione della tensione dei muscoli masticatori in atleti apneisti tramite valutazioni elettromiografiche realizzate prima e dopo un periodo di utilizzo di un bite di rilassamento, al fine di verificarne l'utilità in questo ambito sportivo.
Materiali e Metodi - Per lo studio sono stati selezionati 4 atleti, due maschi e due femmine, di età compresa tra 23 e 39 anni, con caratteristiche equiparabili per tipologia di allenamento e per livello agonistico.
Previa acquisizione di un consenso informato individuale, la valutazione clinica-anamnestica, raccolta in una apposita cartella composta da una parte ortodontica e da una parte gnatologica, ha permesso di escludere la presenza di DTM (disturbi temporomandibolari) data l’assenza di sintomatologia dolorosa attuale e pregressa, assenza di dolorabilità alla palpazione muscolare intra ed extraorale, assenza di limitazione funzionale testimoniata da corretti range di apertura, lateralità e protrusiva, assenza di rumori articolari anche provocati. Per ogni atleta analizzato sono state successivamente eseguite una ortopantomografia e una teleradiografia in proiezione latero-laterale, una serie di fotografie intra ed extraorali e sono stati realizzati dei modelli di studio montati in articolatore. Dopo un iniziale esame elettromiografico a ciascun atleta è stata fornita una placca di rilassamento da portare di notte per i primi tre mesi, di notte e durante gli allenamenti sportivi per i tre mesi successivi. Al fine di quantificare i cambiamenti di tensione nei muscoli massetere e temporale sono state eseguite altre due sedute di elettromiografia di superficie, a distanza di tre mesi l' una dall' altra, durante l'utilizzo del bite; in ogni seduta sono stati eseguiti tre rilevamenti, in serramento, in posizione di riposo e in apnea per un tempo massimale stabilito per tutti gli atleti in 2 minuti. Quest’ultimo rilevamento ha lo scopo di valutare l’influenza di una stato di ipossia, simile a quello che si verifica durante la prestazione sportiva, sulla situazione muscolare.
Per gli esami elettromiografici, previa accurata detersione della cute e reperimento dei fasci muscolari sono stati applicati 4 elettrodi di superficie sui muscoli temporale anteriore e massetere, in ambedue lati destro e sinistro. Al fine di standardizzare la procedura, prima della registrazione dei potenziali, sono stato eseguite 2 fotografie per documentare la localizzazione degli elettrodi.
Le registrazioni sono state eseguite secondo il seguente schema: in serramento (il soggetto respira); in posizione di riposo (il soggetto respira); in apnea per un tempo massimale uguale per tutti gli atleti (2 minuti). Nella 2° elettromiografia (dopo 3 mesi di applicazione del bite solo di notte) e nella 3° elettromiografia (a 6 mesi, dopo 3 mesi di applicazione del bite sia in allenamento che di notte) è stata aggiunta una quarta registrazione, effettuata in apnea con bite per un tempo massimale uguale alle prove precedenti (2minuti).
Conclusioni - Nonostante i limiti imposti dall'esiguità del campione considerato, data la difficoltà di reperire apneisti con caratteristiche omogenee e in assenza di preesistenti DTM, l'analisi dei risultati ottenuti con l'esame elettromiografico, pur se in prove a secco ci consentirà di definire in quali termini possano cambiare i potenziali in un soggetto apneista dopo l' applicazione di un bite sia mentre respira, sia durante l'attività apneistica. Tali considerazioni ci offriranno lo spunto per comprendere se l'utilizzo del bite durante l'attività sportiva possa aumentare il rilassamento muscolare nel distretto cranio-facciale favorendo, quindi, un miglioramento della prestazione agonistica di questi atleti
Effects of nanofillers on mechanical properties of fiber-reinforced composites polymerized with light-curing and additional postcuring
No full textThe purpose of the present study was to evaluate the effect of nanofillers on the mechanical properties of 2 sizes (diameters 0.6 and 0.9 mm) of conventional and nanofilled fiber-reinforced composites (FRCs) polymerized with conventional light-curing and additional postcuring.
METHODS:
The FRCs samples were divided into 8 groups (10 specimens each). Conventional FRCs with glass fibers preimpregnated with polymethyl methacrylate (groups 1, 2, 3 and 4) and FRCs with impregnating solution containing 32% nanofilled resin (groups 5, 6, 7 and 8) were tested in 2 different sections (0.6 and 0.9 mm in diameter). Two different polymerizations were analyzed: hand light-curing for 40 seconds with an halogen light, and additional postcuring for 25 minutes in a light-curing oven. Each sample was evaluated with a 3-point bending test on a universal testing machine, after 48 hours of dry storage. All of the data were statistically analyzed.
RESULTS:
After oven postcuring, nanofilled FRCs exhibited significantly higher load values than conventional FRCs. No significant differences were found when comparing conventional and nanofilled FRCs after hand light-curing. Moreover, 0.6-mm FRCs showed significantly lower load values than 0.9-mm FRCs, both for conventional and nanofilled FRCs.
CONCLUSIONS:
Nanofilled FRCs showed higher load values after additional oven postcuring
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
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
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