Exploring the Impact of Affective Processing on Visual Perception of Large-Scale Spatial Environments

This thesis explores the interaction between emotions and visual perception using large scale spatial environment as the medium of this interaction. Emotion has been documented to have an early effect on scene perception (Olofsson, Nordin, Sequeira, & Polich, 2008). Yet, most popularly-used scene stimuli, such as the IAPS or GAPED stimulus sets often depict salient objects embedded in naturalistic backgrounds, or “events” which contain rich social information, such as human faces or bodies. And thus, while previous studies are instrumental to our understanding of the role that social-emotion plays in visual perception, they do not isolate the effect of emotion from the social effects in order to address the specific role that emotion plays in scene recognition – defined here as the recognition of large-scale spatial environments. To address this question, we examined how early emotional valence and arousal impact scene processing, by conducting an Event-Related Potential (ERP) study using a well-controlled set of scene stimuli that reduced the social factor, by focusing on natural scenes which did not contain human faces or actors. The study comprised of two stages. First, we collected affective ratings of 440 natural scene images selected specifically so they will not contain human faces or bodies. Based on these ratings, we divided our scene stimuli into three distinct categories: pleasant, unpleasant, and neutral. In the second stage, we recorded ERPs from a separate group of participants as they viewed a subset of 270 scenes ranked highest in each of their respective categories. Scenes were presented for 200ms, back-masked using white noise, while participants performed an orthogonal fixation task. We found that emotional valence had significant impact on scene perception in which unpleasant scenes had higher P1, N1 and P2 peaks. However, we studied the relative contribution of emotional effect and low-level visual features using dominance analysis which can compare the relative importance of predictors in multiple regression. We found that the relative contribution of emotional effect and low-level visual features (operationalized by the GIST model, (Oliva & Torralba, 2006)) had complete dominance over emotional effects (both valence and arousal) on most early peaks and areas under the curve (AUC). We also found out that affective ratings were significantly influenced by the GIST intensities of the scenes in which scenes with high GIST intensities were more likely to be rated as unpleasant. We concluded that emotional impact in our stimulus set of natural scenes was mostly due to bottom-up effect on scene perception and that controlling for the low-level visual features (particularly the GIST intensity) would be an important step to confirm the affective impact on scene perception

Basic life support: Knowledge and attitude among dental students and Staff in the College of Dentistry, King Saud University

AbstractObjective: To assess and compare the level of knowledge and attitude toward basic life support among bachelor of dental surgery clinical students (third-, fourth-, and fifth-year dental students), dental interns, postgraduate students and faculty in the Dental College at King Saud University, Riyadh, Saudi Arabia. Material and methods: A previously validated self-select questionnaire was randomly distributed to the participants. The structured questionnaires consist of demographic data, knowledge and attitude of the participants related to basic life support. Results: 454 participants completed the surveys with response rate of 77.85%. The mean knowledge score for the participants was 5.99 with a median score of six. A highly statistically significant difference was detected among the different academic groups (analysis of variance ANOVA; F=9.756, P<0.001). The mean scores of the third-year students were significantly the highest, while fifth-year students showed the lowest knowledge score. The majority of the participants (93.6%) thought that dentists and dental students should know about basic life support and that it should be included in the undergraduate dental curriculum. Conclusion: Our findings demonstrate that dental students and staff had inadequate basic life support knowledge. However, they had positive attitudes toward it

Patient-reported outcomes and framework fit accuracy of removable partial dentures fabricated using digital techniques: A systematic review and meta-analysis

Purpose: This review aimed to summarize the evidence on patient-reported outcomes and clinical performance of digitally fabricated removable partial dentures (RPDs) compared to traditionally fabricated dentures. Methods: Three databases were systematically searched (PubMed, CENTRAL, and Wiley online library) for clinical studies comparing digitally and conventionally fabricated RPDs regardless of data acquisition methods used for fabrication. The Cochrane Collaboration risk of bias assessment tool 2 and the Oxford Center for Evidence-based Medicine tool were used to assess risk of bias, and level of evidence, respectively. Descriptive narrative analysis was used to summarize data on patient-reported outcomes, as there were inadequate studies to pool data in a meta-analysis. A random-effects model was used to analyze the data of framework fit accuracy. Results: Ten randomized controlled trials were included in the systematic review, and 4 were included in the meta-analysis. Two studies showed that digitally fabricated RPDs are associated with higher patient satisfaction than conventionally fabricated RPDs (with a mean difference of 12.5 mm on a 100-satisfaction scale, p =.008). The pooled standardized mean difference for framework fit accuracy was 0.49 (p = 0.02) in favor of conventionally fabricated RPDs, which showed that conventionally fabricated RPDs have a quantitatively better fit compared to digitally fabricated RPDs. However, clinical evaluation studies showed that both frameworks have clinically acceptable fit. Conclusions: Current evidence shows that digitally fabricated RPDs are associated with higher patient satisfaction compared to conventionally fabricated RPDs. However, the scarcity of literature here warrants the generalization of this conclusion. Both digitally and conventionally fabricated metal RPD frameworks showed acceptable fit clinically

Highly Flexible Polyaniline-Based Implantable Electrode Materials for Neural Sensing/Stimulation Applications

Implantable bioelectrodes have the potential to advance neural sensing and muscle stimulation, mainly in patients with peripheral nerve injuries. They function as the transducer at the interface between the damaged nerve and the muscle which is controlled by that nerve. This work reports the fabrication and characterization of novel, low-cost, flexible bioelectrodes based on polyaniline (PANI) and supported with silicone polymer. The fabricated electrodes were evaluated for their electrical and mechanical characteristics. PANI was used as the main transducer component in this fabrication. The characterization methods included electrical conductivity, capacitive behavior, long-term electrical impedance, and mechanical evaluation. The results of the fabricated PANI-silicone-based samples displayed a bulk impedance of 0.6 kΩ with an impedance of 1.6 kΩ at the frequency of 1 kHz. Furthermore, the bioelectrodes showed a charge storage capacity range from 0.0730 to 4.3124 C/cm2. The samples were stable when subjected to cyclic voltammetry tests. The bioelectrodes revealed very flexible mechanical properties as observed from the value of Young’s modulus (in the order of MPa) which was less than that of skin. Hence, the PANI-based bioelectrodes reported herein showed promising electrochemical characteristics with high flexibility

Tooth Shade Preferences among the General Public

Purpose: To identify laypersons? most preferred tooth shade as a function of observer and patient factors, namely patients? skin shade and observers? socio-demographics. Materials and Methods: Two online surveys using computer-designed perioral images with different shades of the skin and teeth were distributed to participants in Montreal (Canada) and San Francisco (USA). The first survey (n = 120) was designed to assess public preferences of tooth shade value, hue and chroma as a function of the skin color of the perioral image (model), and the demographic characteristics of the observer. The first survey included 6 sets of 9 identical perioral images. A different skin shade (from very dark to very light) was used for each set of images, and each set of images presented teeth with different tooth shades which included three different levels of value (2M1, 3M1, 4M1), hue (3L1.5, 3M1, 3R1.5), and chroma (3M1, 3M2, 3M3) of the Vita 3D Master shade guide. Participants were asked to choose their preferred image for each category (value, hue, chroma) within each set of skin shades. A second survey was performed to pinpoint the tooth shade that is preferred the most by the general public. In this survey, images with four tooth shades (1M1, 2M1, 3M1, 4M1) and 6 skin shades were distributed (n = 70). Ordinal logistic regression was used to identify significant predictors of preferred tooth shades. Results: Most of the participants preferred teeth with the highest value (54%), a neutral hue (59%) and the lowest chroma (89%). About 75% of the participants preferred 1M1 the lightest tooth shade over other shades regardless of their demographics or skin color of the model. Among the observer-related variable, age was the most significant predictor of people preferred tooth shade (p = 0.019). Conclusion: This study showed that there are common preferences in terms of tooth shade value, hue and chroma among participants regardless of demographic variables and facial skin shades. This data could guide dentists for tooth shade selection in the clinical practice.Scopu

Digital removable partial dentures

Recently, digital techniques have revolutionized the production of partial removable dental prostheses (PRDPs). This chapter reviews current systems for PRDP production, how they are done in clinical practice, advantages and limitations, and current literature regarding their clinical performance. Currently, several digital techniques are available in the market for PRDP production including subtractive and additive techniques. Subtractive milling technique is mainly effective for non-metal PRDP, whereas additive techniques are used mainly in metal PRDP. Digital techniques expand the range of materials that can be utilized for PRDP production, including new polymers (PEEK), and facilitate previously difficult procedures such as casting titanium PRDP, which can be produced more easily with digital methods. This review shows that available evidence suggests that these techniques have promising clinical results. Laser sintering resulted in higher patient’s satisfaction compared to conventional PRDP. However, long-term clinical trials are recommended to explore the long-term effects of these techniques. Moreover, this review showed the lack of evidence on the clinical performance of non-metal partial removable dental prostheses.Other Information Published in: Clinical Dentistry Reviewed License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s41894-020-00074-y</p