Shear bond strength of brackets to demineralize enamel after different pretreatment methods

Objective: To compare the influence of demineralized and variously pretreated demineralized enamel on the shear bond strength of orthodontic brackets. Materials and Methods: Sixty bovine enamel specimens were allocated to five groups (n  =  12). Specimens of group 1 were not demineralized and were not pretreated, but served as controls. The other specimens were demineralized to form artificial carious lesions. Samples from group 2 were only demineralized and were kept untreated in artificial saliva. The other samples were pretreated with highly concentrated fluoride preparations (group 3: Elmex Gelee, 1.23% F; group 4: Clinpro White Varnish, 2.23% F) or with an infiltrating resin (group 5: Icon). After respective pretreatments, brackets were adhesively fixed on all specimens with an adhesive system after etching with 35% phosphoric acid and application of a primer and bracket resin cement (Transbond XT). Bracket shear bond strength was evaluated with a universal testing machine. Statistical analysis was performed by one-way analysis of variance followed by a post-hoc Scheffé test. Results: Shear bond strength in control group 1 was statistically significantly greater compared with that in all other groups. Application of the infiltrating resin Icon (group 5) as pretreatment resulted in statistically significantly greater bond strength as compared with pretreatments with fluoride compounds (groups 3 and 4) and treatment provided without pretreatment (group 2). Groups 2, 3, and 4 did not significantly differ from each other. Conclusion: Pretreatment with the infiltrating resin is a beneficial approach to increasing the shear bond strength of brackets to demineralized enamel

Spontaneous and deliberate future thinking: A dual process account

© 2019 Springer Nature.This is the final published version of an article published in Psychological Research, licensed under a Creative Commons Attri-bution 4.0 International License. Available online at: https://doi.org/10.1007/s00426-019-01262-7.In this article, we address an apparent paradox in the literature on mental time travel and mind-wandering: How is it possible that future thinking is both constructive, yet often experienced as occurring spontaneously? We identify and describe two ‘routes’ whereby episodic future thoughts are brought to consciousness, with each of the ‘routes’ being associated with separable cognitive processes and functions. Voluntary future thinking relies on controlled, deliberate and slow cognitive processing. The other, termed involuntary or spontaneous future thinking, relies on automatic processes that allows ‘fully-fledged’ episodic future thoughts to freely come to mind, often triggered by internal or external cues. To unravel the paradox, we propose that the majority of spontaneous future thoughts are ‘pre-made’ (i.e., each spontaneous future thought is a re-iteration of a previously constructed future event), and therefore based on simple, well-understood, memory processes. We also propose that the pre-made hypothesis explains why spontaneous future thoughts occur rapidly, are similar to involuntary memories, and predominantly about upcoming tasks and goals. We also raise the possibility that spontaneous future thinking is the default mode of imagining the future. This dual process approach complements and extends standard theoretical approaches that emphasise constructive simulation, and outlines novel opportunities for researchers examining voluntary and spontaneous forms of future thinking.Peer reviewe

On the Nature of Everyday Prospection: A Review and Theoretical Integration of Research on Mind-Wandering, Future Thinking, and Prospective Memory

© 2020 The Authors. The final, definitive version of this paper has been published by Sage Publications Ltd. All rights reserved. It is available at: https://doi.org/10.1177/1089268020918843The ability to imagine and simulate events that may happen in the future has been studied in several related but independent research areas (e.g., episodic future thinking, mind-wandering, prospective memory), with a newly emerging field of involuntary future thinking focusing primarily on the spontaneous occurrence of such thoughts. In this article, we review evidence from these diverse fields to address important questions about why do people think about the future, what are the typical and most frequent contents of such thoughts, and how do these thoughts occur (are they spontaneous or constructed deliberately). Results of the literature review provide support for the pragmatic theory of prospection, by showing that when people engage in prospective thought naturally, without being explicitly instructed to do so, they predominantly think about their upcoming tasks and planned activities instead of simulating plausible but novel hypothetical scenarios. Moreover, prospective thoughts are more often spontaneous than deliberate and effortful, and their occurrence seems to increase the likelihood of planned activities being completed in the future. The findings are discussed in the context of a new “pragmatic dual process account” of future thinking, and new avenues for future research on prospection are outlined.Peer reviewe

Why are we not flooded by involuntary thoughts about the past and future? Testing the cognitive inhibition dependency hypothesis

© The Author(s) 2018In everyday life, involuntary thoughts about future plans and events occur as often as involuntary thoughts about the past. However, compared to involuntary autobiographical memories (IAMs), such episodic involuntary future thoughts (IFTs) have become a focus of study only recently. The aim of the present investigation was to examine why we are not constantly flooded by IFTs and IAMs given that they are often triggered by incidental cues while performing undemanding activities. One possibility is that activated thoughts are suppressed by the inhibitory control mechanism, and therefore depleting inhibitory control should enhance the frequency of both IFTs and IAMs. We report an experiment with a between-subjects design, in which participants in the depleted inhibition condition performed a 60-min high-conflict Stroop task before completing a laboratory vigilance task measuring the frequency of IFTs and IAMs. Participants in the intact inhibition condition performed a version of the Stroop task that did not deplete inhibitory control. To control for physical and mental fatigue resulting from performing the 60-min Stroop tasks in experimental conditions, participants in the control condition completed only the vigilance task. Contrary to predictions, the number of IFTs and IAMs reported during the vigilance task, using the probe-caught method, did not differ across conditions. However, manipulation checks showed that participants’ inhibitory resources were reduced in the depleted inhibition condition, and participants were more tired in the experimental than in the control conditions. These initial findings suggest that neither inhibitory control nor physical and mental fatigue affect the frequency of IFTs and IAMs.Peer reviewedFinal Published versio

Dissociation of Subjectively Reported and Behaviorally Indexed Mind Wandering by EEG Rhythmic Activity

Inattention to current activity is ubiquitous in everyday situations. Mind wandering is an example of such a state, and its related brain areas have been examined in the literature. However, there is no clear evidence regarding neural rhythmic activities linked to mind wandering. Using a vigilance task with thought sampling and electroencephalography recording, the current study simultaneously examined neural oscillatory activities related to subjectively reported and behaviorally indexed mind wandering. By implementing time-frequency analysis, we found that subjectively reported mind wandering, relative to behaviorally indexed, showed increased gamma band activity at bilateral frontal-central areas. By means of beamformer source imaging, we found subjectively reported mind wandering within the gamma band to be characterized by increased activation in bilateral frontal cortices, supplemental motor area, paracentral cortex and right inferior temporal cortex in comparison to behaviorally indexed mind wandering. These findings dissociate subjectively reported and behaviorally indexed mind wandering and suggest that a higher degree of executive control processes are engaged in subjectively reported mind wandering

Mind wandering and task-focused attention: ERP correlates

Previous studies looking at how Mind Wandering (MW) impacts performance in distinct Focused Attention (FA) systems, using the Attention Network Task (ANT), showed that the presence of pure MW thoughts did not impact the overall performance of ANT (alert, orienting and conflict) performance. However, it still remains unclear if the lack of interference of MW in the ANT, reported at the behavioral level, has a neurophysiological correspondence. We hypothesize that a distinct cortical processing may be required to meet attentional demands during MW. The objective of the present study was to test if, given similar levels of ANT performance, individuals predominantly focusing on MW or FA show distinct cortical processing. Thirty-three healthy participants underwent an EEG high-density acquisition while they were performing the ANT. MW was assessed following the ANT using an adapted version of the Resting State Questionnaire (ReSQ). The following ERP's were analyzed: pN1, pP1, P1, N1, pN, and P3. At the behavioral level, participants were slower and less accurate when responding to incongruent than to congruent targets (conflict effect), benefiting from the presentation of the double (alerting effect) and spatial (orienting effect) cues. Consistent with the behavioral data, ERP's waves were discriminative of distinct attentional effects. However, these results remained true irrespective of the MW condition, suggesting that MW imposed no additional cortical demand in alert, orienting, and conflict attention tasks.Acknowledgements Óscar F. Gonçalves was funded by the Brazilian National Counsel for Scientific and Technological Development (CNPq) as a Special Visiting Researcher of the Science Without Borders program (401143/2014-7). Paulo S Boggio was funded by a CNPq researcher fellowship (311641/2015-6). Olivia Morgan Lapenta and Tatiana Conde were supported by two postdoctoral grants from CNPq (150249/2017-9 and 152358/2016-1). Sandra Carvalho was funded by the Portuguese Foundation for Science and Technology (FCT) with the grant IF/00091/2015. Gabriel Rêgo was supported by a PhD grant from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP-2015/18713-9). This work was partially supported by FEDER funds through the Programa Operacional Factores de Competitividade – COMPETE and by national funds through FCT – Fundação para a Ciência e a Tecnologia (P2020-PTDC/MHC-PCN/3950/2014).info:eu-repo/semantics/publishedVersio

Neural Correlates of Ongoing Conscious Experience: Both Task-Unrelatedness and Stimulus-Independence Are Related to Default Network Activity

The default mode network (DMN) is a set of brain regions that consistently shows higher activity at rest compared to tasks requiring sustained focused attention toward externally presented stimuli. The cognitive processes that the DMN possibly underlies remain a matter of debate. It has alternately been proposed that DMN activity reflects unfocused attention toward external stimuli or the occurrence of internally generated thoughts. The present study aimed at clarifying this issue by investigating the neural correlates of the various kinds of conscious experiences that can occur during task performance. Four classes of conscious experiences (i.e., being fully focused on the task, distractions by irrelevant sensations/perceptions, interfering thoughts related to the appraisal of the task, and mind-wandering) that varied along two dimensions (“task-relatedness” and “stimulus-dependency”) were sampled using thought-probes while the participants performed a go/no-go task. Analyses performed on the intervals preceding each probe according to the reported subjective experience revealed that both dimensions are relevant to explain activity in several regions of the DMN, namely the medial prefrontal cortex, posterior cingulate cortex/precuneus, and posterior inferior parietal lobe. Notably, an additive effect of the two dimensions was demonstrated for midline DMN regions. On the other hand, lateral temporal regions (also part of the DMN) were specifically related to stimulus-independent reports. These results suggest that midline DMN regions underlie cognitive processes that are active during both internal thoughts and external unfocused attention. They also strengthen the view that the DMN can be fractionated into different subcomponents and reveal the necessity to consider both the stimulus-dependent and the task-related dimensions of conscious experiences when studying the possible functional roles of the DMN

Resting-State Functional Connectivity between Fronto-Parietal and Default Mode Networks in Obsessive-Compulsive Disorder

Background: Obsessive-compulsive disorder (OCD) is characterized by an excessive focus on upsetting or disturbing thoughts, feelings, and images that are internally-generated. Internally-focused thought processes are subserved by the ‘‘default mode network’ ’ (DMN), which has been found to be hyperactive in OCD during cognitive tasks. In healthy individuals, disengagement from internally-focused thought processes may rely on interactions between DMN and a frontoparietal network (FPN) associated with external attention and task execution. Altered connectivity between FPN and DMN may contribute to the dysfunctional behavior and brain activity found in OCD. Methods: The current study examined interactions between FPN and DMN during rest in 30 patients with OCD (17 unmedicated) and 32 control subjects (17 unmedicated). Timecourses from seven fronto-parietal seeds were correlated across the whole brain and compared between groups. Results: OCD patients exhibited altered connectivity between FPN seeds (primarily anterior insula) and several regions of DMN including posterior cingulate cortex, medial frontal cortex, posterior inferior parietal lobule, and parahippocampus. These differences were driven largely by a reduction of negative correlations among patients compared to controls. Patients also showed greater positive connectivity between FPN and regions outside DMN, including thalamus, lateral frontal cortex, and somatosensory/motor regions

The concept of three-dimensional model of "Wieliczka" Salt Mine workings to improve the conditions of the mine safety management

W artykule przedstawiono założenia techniczne oraz omówiono uwarunkowania opracowania nowej koncepcji trójwymiarowego modelu wyrobisk górniczych Kopalni Soli w Wieliczce. Główną przesłanką budowy trójwymiarowego modelu kopalni jest ocena możliwości zarządzania bezpieczeństwem trasy turystycznej w kopalni. W pierwszej fazie badań określono optymalną metodykę odwzorowania i generalizacji płaskich danych mapy górniczej do określonego typu obiektu trójwymiarowego. Poza geometrią wyrobisk w koncepcji uwzględniono również utworzenie symboli reprezentujących te elementy infrastruktury i wyposażenia górniczego, które ważne są z punktu widzenia bezpieczeństwa ruchu kopalni. Symbole trójwymiarowego modelu wyrobisk skojarzono z symbolami stosowanymi w normach map górniczych. Następnie model wzbogacono o informacje geologiczne przy zastosowaniu trójwymiarowej kalibracji geologicznych przekrojów pionowych i poziomych górotworu. W celu wprowadzenia systemu zarządzania projektem zastosowano schemat projektu typu GIS (Geography Information System). Obiekty geometryczne zostały podłączone do relacyjnej bazy danych przestrzennych. W ramach projektu obiekty uzyskały dodatkowe informacje atrybutowe, pozwalające na efektywne wykonywanie zapytań geoatrybutowych oraz wykonywania analiz przestrzennych.This paper presents technical assumptions and describes the conditions of development of a new concept of three-dimensional model of "Wieliczka" salt mine workings. The main reason for the development of the model is the evaluation of the possibility of safety management of the tourist route in the mine. The first phase of the research determines the optimal methodology of generalization and transformation of flat data of the mining map to the defined type of the three-dimensional model. Apart from geometry, the concept includes the creation of symbols representing components of the infrastructure and mining equipment which are crucial from the point of view of mine operation safety. The symbols used in the three-dimensional model of workings were linked to the symbols implemented in the mining map standards. Afterwards, the model was enriched with geological information by the use of three-dimensional calibration of geological horizonal and vertical cross-sections of the rock mass. In order to introduce the administration system, the scheme of GIS-type Project was used. Geometrical objects were connected to the relational spatial data base. As part of the project, the objects obtained additional information which allows to make geoattributic queries and spatial analyses

Repairability of CAD/CAM high-density PMMA- and composite-based polymers

OBJECTIVE The study aimed to analyse the shear bond strength of computer-aided design and computer-aided manufacturing (CAD/CAM) polymethyl methacrylate (PMMA)- and composite-based polymer materials repaired with a conventional methacrylate-based composite after different surface pretreatments. METHODS Each 48 specimens was prepared from six different CAD/CAM polymer materials (Ambarino high-class, artBloc Temp, CAD-Temp, Lava Ultimate, Telio CAD, Everest C-Temp) and a conventional dimethacrylate-based composite (Filtek Supreme XTE, control) and aged by thermal cycling (5000 cycles, 5-55 °C). The surfaces were left untreated or were pretreated by mechanical roughening, aluminium oxide air abrasion or silica coating/silanization (each subgroup n = 12). The surfaces were further conditioned with an etch&rinse adhesive (OptiBond FL) before the repair composite (Filtek Supreme XTE) was adhered to the surface. After further thermal cycling, shear bond strength was tested, and failure modes were assessed. Shear bond strength was statistically analysed by two- and one-way ANOVAs and Weibull statistics, failure mode by chi(2) test (p ≤ 0.05). RESULTS Shear bond strength was highest for silica coating/silanization > aluminium oxide air abrasion = mechanical roughening > no surface pretreatment. Independently of the repair pretreatment, highest bond strength values were observed in the control group and for the composite-based Everest C-Temp and Ambarino high-class, while PMMA-based materials (artBloc Temp, CAD-Temp and Telio CAD) presented significantly lowest values. For all materials, repair without any surface pretreatment resulted in adhesive failures only, which mostly were reduced when surface pretreatment was performed. CONCLUSIONS Repair of CAD/CAM high-density polymers requires surface pretreatment prior to adhesive and composite application. However, four out of six of the tested CAD/CAM materials did not achieve the repair bond strength of a conventional dimethacrylate-based composite. CLINICAL RELEVANCE Repair of PMMA- and composite-based polymers can be achieved by surface pretreatment followed by application of an adhesive and a conventional methacrylate-based composite