Browsing by Author "Mohammadi, S."

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Open Access
Attentional bias to threat-related information among individuals with dental complaints: The role of pain expectancy
(Frontiers Media S.A., 2018) Dehghani, M.; Mohammadi, S.; Sharpe, L.; Khatibi, Ali
Expecting pain can be perceived as a threat may involve recruitment of cognitive strategies (such as attentional avoidance) which might help the person to reduce distress. The ecological validity of the paradigms aiming to study the attentional biases toward or away from threatening stimuli by manipulating the perception of threat in experimental settings has been questioned. Therefore, the current study aims to investigate the attentional bias toward or away from the threat when a confrontation with a real threatening and painful condition would be expected (i.e., dental treatment). One hundred and twenty-seven patients referred to three dentistry clinics for a dental treatment (experiment participants) and 30 individuals with no dental complaints (control participants) completed this study. Patients were randomly allocated to a high pain expectancy (HPE: n = 65) or a low pain expectancy (LPE: n = 62) expectancy condition. All participants completed questionnaires of distress, fear of pain, and fear of dental pain. Furthermore, they participated in a dot-probe task that assessed their attention to painful faces, dental pictures, and happy faces. In addition, before the treatment, participants reported their anticipated pain intensity and after the treatment, they reported the pain intensity that they perceived during the treatment using two separate visual analog scales. Patients in the HPE group showed a bias away from dental pictures compared to LPE and control group participants. HPE group patients also reported greater pain intensity during the treatment compared to LPE patients. Greater attentional bias away from dental pictures among HPE patients was associated with higher levels of fear of pain, fear of dental pain, and stress. Avoidance of highly salient threatening images can be seen as an unhelpful emotion-regulation strategy that individuals use to manage their fears. However, in this study, avoidance was associated with poorer outcomes.
Open Access
Flexible strain sensors based on electrostatically actuated graphene flakes
(Institute of Physics Publishing, 2015) Fardindoost, S.; Alipour, A.; Mohammadi, S.; Gökyar, S.; Sarvari, R.; Iraji Zad, A.; Demir, Hilmi Volkan
In this paper we present flexible strain sensors made of graphene flakes fabricated, characterized, and analyzed for the electrical actuation and readout of their mechanical vibratory response in strain-sensing applications. For a typical suspended graphene membrane fabricated with an approximate length of 10 μm, a mechanical resonance frequency around 136 MHz with a quality factor (Q) of ∼60 in air under ambient conditions was observed. The applied strain can shift the resonance frequency substantially, which is found to be related to the alteration of physical dimension and the built-in strain in the graphene flake. Strain sensing was performed using both planar and nonplanar surfaces (bending with different radii of curvature) as well as by stretching with different elongations. © 2015 IOP Publishing Ltd.