1,720,992 research outputs found
Serum effect on the electrochemical behaviour of titanium, Ti6Al4V and Ti6Al7Nb alloys in sulphuric acid and sodium hydroxide
No full textThe corrosion behaviour of cp titanium Ti6Al4V and Ti6Al7Nb alloys is investigated in 2 M sulphuric acid and 2 M sodium hydroxide with and without additions of bovine serum in order to get an insight into the effect of a biological electrolyte on the active corrosion of widely used metallic implants. Ti6Al7Nb alloy shows the highest corrosion resistance in 2 M sulphuric acid, whereas it is the least corrosion-resistant in 2 M sodium hydroxide. Bovine serum inhibits the hydrogen evolution as well as the anodic dissolution reactions in both sulphuric acid and sodium hydroxide. However, the cathodic efficiency of serum in sodium hydroxide is significantly higher than in sulphuric acid. Besides, the results suggest that serum forms a 2-D adsorption layer on the implant materials. Additionally, the surface coverage in sodium hydroxide is ca. 90%, while in acidic solutions only ca. 40%
Il lato oscuro dell'empatia: Quando entrare in intimità emotiva con una persona causa chiusura e distorsione cognitiva [The dark side of empathy: When empathizing causes cognitive closure and perceptual distortion]
No full textIn che modo empatia e ostilità possono distorcere la percezione di ciò che l’altro sta comunicando? Alla luce della teoria delle prospettive multiple, sia l’empatia che l’ostilità dovrebbero indurre chiusura cognitiva, e influenzare, di conseguenza, la capacità di rilevare contraddizioni nel discorso altrui. In particolare, dal momento che le contraddizioni caratterizzano negativamente chi parla, l’ipotesi è che un atteggiamento empatico verso l’altro riduca la rilevazione di contraddizioni nel suo discorso, e, viceversa, che un atteggiamento ostile la migliori. In un disegno sperimentale between-subjects, 120 giovani adulti venivano casualmente assegnati a una di tre condizioni: induzione di “empatia” vs. controllo vs. “ostilità”. A tutti veniva mostrata una videointervista nella quale il protagonista si contraddiceva sette volte. Le variabili dipendenti erano il numero di contraddizioni notate e il modo in cui il protagonista veniva caratterizzato, più o meno positivamente. Come ipotizzato, il numero di contraddizioni rilevate variava significativamente tra i tre gruppi, risultando particolarmente basso nel gruppo “empatia” e alto nel gruppo “ostilità” (“empatia”=1.25; controllo=2.98; “ostilità”=3.93), F=31.27, p<.001. Inoltre, il protagonista del video veniva caratterizzato positivamente dal gruppo “empatia”, t=3.28, p=.002, e negativamente dal gruppo “ostilità”, t=3.31, p=.002. I risultati mostrano come entrambe l’empatia e l’ostilità producano nella persona una certa distorsione cognitiva—qui indotta su base emotiva—che a sua volta può fortemente influenzare la percezione del discorso dell’altro e la capacità di coglierne i contenuti. Questo può avere importanti ricadute nelle pratiche professionali che si basano sull’ascolto oggettivo del cliente, come ad esempio nel colloquio clinico
A study of the potentials achieved during mechanical abrasion and the repassivaton rate of titanium and Ti6Al4V in inorganic buffer solutions and bovine serum
No full textTitanium alloys in orthopaedic implants are susceptible to mechanical disruption of the passive film (fretting corrosion). To study this effect, open-circuit potential (ocp) measurements before, during and after mechanical disruption of the passive film in a tribo-electrochemical cell on commercial pure titanium and Ti6Al4V alloy in inorganic buffer solutions in the pH range from 2.0 to 12.0 and calf bovine serum at pH 4.0 and 7.0 are reported. Additionally, the effect of pH, electrolyte and sample composition on the repassivation rate has been investigated. The potentials achieved during the abrasion of Ti6Al4V are the same as those characterizing pure titanium, which indicates that the corrosion current of both materials in the active state is due to the oxidation of titanium. However, commercial pure titanium displays a tendency to repassivate faster than Ti6Al4V in inorganic buffer solutions thanks to the lower critical current density and the higher catalytic activity towards the hydrogen evolution reaction observed on the pure metal in comparison with the alloy.
Proteinaceous solutions like bovine serum, significantly slow down the anodic dissolution and the cathodic reactions both on titanium and the alloy. However, the repassivation rate of the Ti6Al4V is not affected by serum, while that of cp titanium significantly decreases both at pH 4.0 and 7.0
Corrosion behaviour of CoCrMo implant alloy during fretting in bovine serum
No full textCoCrMo alloys in dental skeletal structures and orthopaedic implants are susceptible to mechanical disruption of the passive film. To study this effect the open circuit potential (ocp) of CoCrMo alloy before, during and after mechanical disruption of the passive film in a tribo-electrochemical cell is recorded in serum and inorganic buffered solutions at pH 4.0 and 7.0.
The ocp values achieved during rubbing (rubbing potentials) in serum are in agreement with a reaction mechanism whereby the anodic dissolution reaction involves the formation of the aqueous cations Co(II) and Cr(II) at acidic pHs and the oxides CoO and CrO at neutral and alkaline pHs. It is suggested that the kinetics describing the anodic dissolution reaction of the alloy in serum is under diffusion control, which is responsible for more positive rubbing potential values observed compared to inorganic solutions at the same pH.
The corrosion current of the alloy is significantly lower in serum both at pH 4.0 and 7.0. In addition, the biological electrolyte increases the repassivation rate at neutral pH
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
The dissociation between cognitive and emotional responses to deterrents
No full textThis article reports empirical findings on the strength and dissociation of experimentally
induced cognitive vs. emotional responses to instigators of prejudice towards people
affected by mental illness. Drawing on emotional intensity theory (EIT: Brehm,
1999), the experiment (N = 80) shows how growing and apparently reassuring reasons
(i.e., the deterrents) for not being prejudiced towards ‘the mentally ill’ differentially
affect the intensity of cognitive vs. emotional prejudiced responses. Such reassuring
information was conveyed to participants as the increasing likelihood that ordinary
people typically recover, if affected, from mental illness (likelihood not mentioned,
low [5%], moderate [50%], high [70%]). Whereas the intensity of cognitive responses
tended to diminish linearly with growing reasons for not being prejudiced (η2
= .06),
the intensity of emotional responses followed closely EIT’s predictions, and varied as a
cubic function of deterrence information (η2
= .61), that is, of information ironically
intended to reassure participants. These findings substantiate EIT in two important
respects. For one, they consistently reveal, and nicely conceptually replicate, EIT’s
predicted cubic pattern of paradoxical results for emotional responses with respect to
prejudiced affect. Most importantly, however, they also illustrate—theoretically and
empirically—the expected dissociation between emotional and cognitive responses
to deterrents. In our view, such a dynamic separation and convergence of cognitive
and affective components of prejudice has the full potential to inspire new theoretical
insight and understanding, theory-based research, and the development of evidencebased intervention practices
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