Search Results (69)

Background: We compared the camouflage effect of three white spot lesion (WSL) treatments (infiltration, nano-hydroxyapatite (nHAP) remineralization, and microabrasion) and color stability of the treated surfaces. Methods: Fifty sound extracted teeth were used in the study. WSLs were created on 40 buccal dento-enamel specimens through the use of acidic methylcellulose gel. These specimens were randomly assigned to treatment groups (n = 10 per group): negative controls, nano-hydroxyapatite (nHAP), resin infiltration, and microabrasion. After the treatment, all 50 specimens were immersed in coffee for 7 days. Color measurements were performed four times: at baseline (T0), after the demineralization procedure (T1), after the treatments (T2), and after immersion in coffee (T3). Results: No restoration of the initial enamel color was observed in any of the groups. The ICON and MA groups exhibited the highest masking effect, with the mean ΔE_T0-T2 = 7.46, although the differences among the study groups were insignificant. All three treatments increased the resistance of WSLs to discoloration in coffee compared to the negative control group; however, infiltration (∆E_T2-T3 = 4.13) and microabrasion (∆E_T2-T3 = 3.49) showed a better color stability tendency than nHAP remineralization (∆E_T2-T3 = 7.26). Conclusions: Despite its well-known remineralizing and desensitizing effects, nHAP showed the least masking effect for WSLs and lower color stability compared to resin infiltration and microabrasion. However, none of the methods allowed for complete restoration of the original color. After the discoloration procedure, the color changes in the white spots treated with microabrasion and infiltration were comparable to those of the sound enamel. Full article

Introduction: Virtual reality (VR) has garnered increasing attention in oncology due to its potential to enhance patient care by alleviating anxiety and emotional distress. The present work evaluates the hypothesis proposed by a recent theoretical model that engagement and the sense of presence are key mediators that impact the degree of beneficial effects that VR may have on the emotional well-being of breast cancer patients. Methods: This study draws on data from three previous studies comprising 156 breast cancer patients. The psychological variables of well-being studied included emotional dimensions measured before and after exposure to a virtual environment, as well as factors related to immersive qualities. Correlation and mediation analyses were conducted to explore relationships among said variables, namely, one’s tendency to be immersed in an activity, engagement, spatial presence, and emotional well-being (i.e., valence and arousal) of the patients. Results: Engagement plays a crucial mediating role between tendency of immersion, spatial presence, and positive emotional responses. Patients with a greater tendency toward immersion and higher engagement in the virtual environment showed significant emotional improvements. However, tendency of immersion and spatial presence alone did not directly lead to more positive emotional experiences; their influence was primarily exerted through engagement. Conclusions: Engagement emerges as a fundamental lever for maximizing the psychological benefits of VR in oncology. Clinical interventions using VR should prioritize optimizing engagement in immersive environments to improve patients’ emotional state throughout their cancer treatment journey. Full article

Background: Approach and avoidance bias (AAB) describes automatic behavioral tendencies to react toward environmental stimuli regarding their emotional valence. Traditional setups have provided evidence but often lack ecological validity. The study of the AAB in naturalistic contexts has recently increased, revealing significant methodological challenges. This systematic review evaluates the use of virtual reality (VR) and real-world setups to study the AAB, summarizing methodological innovations and challenges. Methods: We systematically reviewed peer-reviewed articles employing VR and real-world setups to investigate the AAB. We analyzed experimental designs, stimuli, response metrics, and technical aspects to assess their alignment with research objectives and identify limitations. Results: This review included 14 studies revealing diverse methodologies, stimulus types, and novel behavioral responses, highlighting significant variability in design strategies and methodological coherence. Several studies used traditional reaction time measures yet varied in their application of VR technology and participant interaction paradigms. Some studies showed discrepancies between simulated and natural bodily actions, while others showcased more integrated approaches that preserved their integrity. Only a minority of studies included control conditions or acquired (neuro)physiological data. Conclusions: VR offers a potential ecological setup for studying the AAB, enabling dynamic and immersive interactions. Our results underscore the importance of establishing a coherent framework for investigating the AAB tendencies using VR. Addressing the foundational challenges of developing baseline principles that guide VR-based designs to study the AAB within naturalistic contexts is essential for advancing the AAB research and application. This will ultimately contribute to more reliable and reproducible experimental paradigms and develop effective interventions that help individuals recognize and change their biases, fostering more balanced behaviors. Full article

Geothermal energy generation faces challenges in efficiency, partly due to restrictions on reinjection temperatures caused by scaling issues. Therefore, developing strategies to prevent scaling is critical. This study aims to simulate the scaling tendencies and corrosion effects of geothermal fluids on various construction materials used in scaling reactor/retention tank systems. A range of materials, including carbon steel, austenitic stainless steel, duplex stainless steel, two proprietary two-part epoxy coatings, and thermally sprayed aluminium (TSA), were tested in a simulated geothermal brine. Experiments were conducted in a laboratory vessel designed to replicate the wall shear stress conditions expected in a scaling reactor. The tests revealed varying scaling tendencies among the materials, with minimal corrosion observed. The dominant scale formed was calcium carbonate, consistent with geochemical modelling. The findings suggest that despite the high operating temperatures, the risk of corrosion remains low due to the brine’s low chloride content, while the wettability of materials after immersion may serve as a useful indicator for selecting those that promote scaling. Full article

This review examines the relationship between the physiological demands of diving and premature ventricular complexes (PVCs) in divers. In the general population, some individuals have a greater tendency to experience PVCs, often without awareness or a clear understanding of the triggering factors. With the increasing availability and popularity of both scuba and apnoea diving, more people, including those with a predisposition to PVCs, are engaging in these activities. The underwater environment, with its unique stressors, may increase the risk of arrhythmogenic events, particularly PVCs. Here, we review the prevalence, pathophysiology, and aggravating factors of PVCs in divers, emphasising the need for a comprehensive cardiovascular assessment. Evidence suggests a higher prevalence of PVCs in divers compared with the general population, influenced by factors such as age, dive depth, gas bubbles, cold water immersion, pre-existing cardiovascular diseases, and lifestyle factors. The change in environment during diving could potentially trigger an increased frequency of PVCs, especially in individuals with a pre-existing tendency. We discuss diagnostic strategies, management approaches, and preventive measures for divers with PVCs, noting that although guidelines for athletes can be adapted, individual assessment is crucial. Significant knowledge gaps are identified, highlighting the need for future research to develop evidence-based guidelines and understand the long-term significance of PVCs in divers. This work aims to evaluate potential contributing factors to PVCs in divers and identify individuals who may be at higher risk of experiencing major adverse cardiovascular events (MACEs). This work aims to improve diver safety by promoting collaboration between cardiologists and diving medicine specialists and by identifying key areas for future investigation in this field. This work aims to improve the safety and well-being of divers by understanding the cardiovascular challenges they face, including pressure changes, cold water immersion, and hypoxia. We seek to elucidate the relationship between these challenges and the occurrence of PVCs. By synthesising current evidence, identifying knowledge gaps, and proposing preliminary recommendations, we aim to encourage collaboration between cardiologists and diving medicine specialists to optimise the screening, management, and risk stratification of PVCs in the diving population. Full article

Design plays an integral role in shaping our everyday lives by providing and mediating the objects and relationships we surround ourselves with. As we find our lifestyles inherently unsustainable, design is therefore also implicated. If design is to fully address this issue and meaningfully contribute to future sustainable lifestyles, then it must undergo significant transformation. Part of this transformation must include design education. While many agree on the necessary transformation of design education, disagreements arise as to what this new education might entail and, significantly, how it might be implemented. This article explores how transformations happen in design education and to what extent such education should tackle significant societal issues, including sustainability, amid the increasing complexity and interdependence of modern-day challenges. It investigates practical issues around implementing such education, its challenges and opportunities, as well as how geographical location might help or hinder through aspects such as social or cultural tendencies, infrastructures or regulation and historical context. To this end, six in-depth interviews were conducted with educators at the forefront of this transformation in Scandinavia, most of whom have established courses and programs that address systemic problems and engage students in reflecting and designing to mitigate current challenges. The analysis of interviews utilised an emergent coding method. It led to four important findings that require attention when considering sustainable design education. The findings are (1) these transformations are often driven by impassioned and visionary individuals, (2) new variants of design must incorporate collaborations at all scales and in various formats, (3) increased responsibility arises from immersion in collaborative projects concerning long-term visions, values, and continuity in design beyond current practices and finally, (4) there are some unresolved tensions found in the balance of practical, reflective, and analytical skills needed. At a more abstract level, this paper positions design education as a significant force in transitioning to sustainable futures. Full article

This work is devoted to evaluating the corrosion behaviors of SS 304L and SS 316L in monoethanolamine solutions (MEA) containing SO_X and NO_X pollutants, examining both lean and CO₂-loaded conditions at 25 °C and 40 °C. Electrochemical techniques (potentiodynamic and cyclic polarization) were used along with Scanning Electron Microscopy, Confocal Microscopy and weight loss measurements. The results reveal that the introduction of SO_X and NO_X pollutants increased the corrosion rate, whereas CO₂ loading primarily reduced the corrosion resistance in the lean MEA solution, while its impact on solutions with SO_X and NO_X was less pronounced. This suggests that SO_X and NO_X play primary roles in the metal’s dissolution. Also, SS 316L demonstrated superior corrosion resistance compared to 304L in nearly all of the cases examined. Elevated temperatures were also found to intensify the corrosion rate, indicating a correlation between the corrosion rate and temperature. A microscopic observation and EDX analysis revealed that corrosion products are characterized by high concentrations of iron (Fe) and oxygen (O) as well as carbon (C). There is also an indication of the possible formation of amine complexes, suggesting a potential for amine degradation. No pitting corrosion was observed in SS 304L and SS 316L across any tested solution. Finally, the immersion results expose a tendency for passivity in all amine solutions and at both temperatures after several days of exposure. Moreover, they confirm the very low corrosion rate calculated from potentiodynamic curves due to minimal weight loss after 24 days of immersion. Full article

The laser cladding of nickel-based fusion alloys makes them prone to cracks and defects that affect the overall performance of the coating. In this study, Ni60A coatings were prepared at different preheating temperatures (25 °C, 200 °C, 400 °C and 600 °C). The effect of the preheating temperature of the substrate on the corrosion resistance of the coating as well as on the development of defects were investigated by electrochemical tests and immersion experiments in a 65 wt% H₂SO₄ solution at 60 °C. The results indicate that preheating the substrate to 200 °C can completely eliminate cracks in the coating and reduce porosity. Preheating leads to a decrease in the corrosion resistance of the coating. The size of the porosity defects is related to the law of longitudinal development of the defects. Porosity defects with diameters smaller than 100 μm have a more pronounced tendency to expand vertically than those with diameters larger than 100 μm. Full article

Virtual-reality 3D modeling helps primary school students to develop creative thinking and problem-solving skills. Through hands-on practice, students can understand abstract concepts more intuitively, and can realize the combination of theory and practice. However, in conventional virtual 3D modeling teaching, students often lack immersive modeling experience, and the modeling method may not be in line with the cognitive way of thinking of primary school students, which, in turn, causes high cognitive load. Immersive virtual reality (IVR) environments provide students with more immersive and intuitive interactions, which can help promote students’ cognitive, emotional, and social development. Therefore, this study combined IVR with 3D virtual modeling to form an immersive virtual-reality-based 3D modeling approach (IVR-based 3D modeling) and designed a quasi-experiment to compare it with the conventional virtual reality 3D modeling approach (CVR-based 3D modeling) to explore its effectiveness. The results of the study show that the IVR-based 3D modeling approach significantly enhanced elementary school students’ creative thinking, including its sub-dimensions (e.g., challenge, imagination, and curiosity), when compared to the CVR-based 3D modeling approach. The same conclusion was reached for problem-solving skills. IVR-based 3D modeling also reduced students’ cognitive load during the learning process, especially in terms of mental effort. The results of the interviews complement the experimental results, and the learners’ perceptions of the new approach explain the experimental results to some extent. Full article

Precipitation-hardening stainless steels, like AM 350 and Custom 450, are extensively utilized in various aerospace applications. The latter steel is utilized for applications needing great strength and corrosion resistance. In contrast, the former steel has a good corrosion resistance and moderate strength. The purpose of this study was to analyze transient frequencies in the electrochemical noise of Custom 450 and AM 350 stainless steels that had been passivated for 60 and 90 min at 25 and 49 °C using baths of citric and nitric acid and then immersed in solutions containing 1% sulfuric acid (H₂SO₄) and 5% sodium chloride (NaCl). The potentiodynamic polychromatic curves employed electrochemical techniques and noise (EN) based on the ASTM-G5 and G199 standards. Two methods of data analysis were applied concerning EN: the domain of frequencies (power spectral density, PSD) and the time–frequency domain (Hilbert-Huang Transform). The PHSS passivated in citric acid indicated current densities in the H₂SO₄ solution between 10⁻² and 10⁻³ mA/cm², while those in the NaCl solution were recorded around 10⁻⁴ and 10⁻⁵ mA/cm². The citric acid functions as a passivating agent. The results of the electrochemical noise analysis show that the PHSS passivated in nitric acid displayed a greater corrosion resistance. Moreover, there is a tendency for PHSS to be passivated in nitric acid to corrode locally. Full article

Despite a history of year-by-year reduction in road-crossing harm and fatality in the United States, the trend reversed course in 2009 and road-crossing has grown more hazardous since. Within this tendency, there has been a marked uptick in risk to urban crossers who are neither children nor elderly. The age group in between these extremes represents a bulk of urban crossers, for whom theoretical explanations for crossing behavior that are focused on youth and senior crossing factors often do not apply. New insight is likely required to explain why the rate of crossing harm is growing for the 20–44 age group, but declining among the young and elderly. However, it is difficult to experiment with crossing scenarios in a real-world context, where significant dangers are present and for which the uniqueness of crossers and crossing sites is abundant. In this paper, we introduce an end-to-end system for examining crossing behavior using a unique combination of real human crossing behavior, made safe through the combination of agent-based models, motion capture, virtual geographic environments, and immersive technologies from virtual reality. We demonstrate that this combination of methods can be deployed to examine very high resolution and very high specificities of crossing scenarios and behaviors, with reach to individual crossers and their judgment over tiny windows of space and time. We demonstrate that the system can reproduce known effects from the theoretical literature and from existing case studies, while also generating huge swaths of empirical and diagnostically useful data on crossing actions, interactions, and reactions relative to fleeting events and phenomena of urban geography, traffic dynamics, and ambient pedestrian crowds. To prove the concept, we deploy the system to investigate crossing judgment behavior among the 20–44 age group. Full article

The passivation behavior of steel reinforcements in concrete is significantly influenced by the environment, concrete pore solution, and the passive film formed on the steel surface. The present study used electrochemical methods to successfully characterize the passivation process of steel reinforcements in concrete. The passivation behavior of commonly used HRB400 steel reinforcement material in concrete was studied using various electrochemical parameters quantitatively. As the soaking test time increased, the OCP gradually increased and stabilized after 5 days, indicating that the steel electrode transitioned from an active state to a passive state in the simulated liquid environment of concrete. The steel reinforcement developed a protective passive film that reduced its tendency to corrode. According to EIS, after soaking for one day, the steel electrode showed significant early passivation, indicated by an increase in its arc diameter. The WE arc gradually increased in the first 5 days of immersion, suggesting dynamic passive film formation and development. Beyond 5 days, the passive film stabilized with minimal further changes in its impedance spectrum, indicating carbon steel electrode passivation. The working electrode’s impedance increased significantly on the fifth day, and gradually increased slightly after 10 days, indicating comprehensive coverage by the oxide film. Attributed to the growth and development of the oxide film, the electrode resistance reached a relatively stable state after the fifth day. The shift in corrosion potential offers an indication of the level of passivation of the steel reinforcements. The decrease in the anode Tafel slope and increase in the corrosion potential indicate the formation and stabilization of an oxide film on the steel surface, which is beneficial for its long-term durability in concrete structures. By analyzing the OCP, EIS, and dynamic potential polarization curve method data, it is possible to gain insights into the passivation behavior of steel reinforcements in concrete structures. This study aims to provide a basis for optimizing the corrosion protection of steel reinforcements in concrete structures. The significance of this study lies in a deep understanding of the passivation behavior of steel bars in concrete, providing a theoretical basis for improving the durability and lifespan of steel bars in concrete structures. Full article

Biodiesel has emerged as a progressively widespread and significant alternative to traditional diesel fuel within the transportation sector. Despite its growing popularity, the issue of corrosive tendencies upon interaction with both moving and static components of diesel engines and fuel systems poses a serious concern. This research endeavors to assess the corrosion characteristics of materials commonly found in automotive fuel systems when exposed to various blends of rapeseed oil biodiesel and diesel. The study involved static immersion tests, lasting 3360 h at room temperature, using B0, B20, B40, B60, B80, and B100 fuels. Copper, brass, aluminum, zinc, and stainless steel plate samples were subjected to these tests. The evaluation at the conclusion of the study included weight loss measurements, corrosion rate calculations, and observation of changes in the exposed metal surfaces. Surface morphology was scrutinized using a Bresser LCD MICRO 5MP digital microscope. Additionally, the total acid number (TAN) was employed to assess alterations in fuel acidity before and after the immersion tests. Full article

The long-term stability of a coal pillar dam is a serious concern for coal mine underground reservoirs because of the creep behavior of coal in complex water immersion and mechanical environments. In order to investigate the characteristics of creep deformation of water-immersed coal and develop a proper creep model, this paper implemented a series of creep experiments of coal via multistage loading at various water-immersion times. The experiment data were analyzed, in terms of immersion-induced damage, elasto-plastic performance, creep behavior, etc., suggesting obvious mechanical properties’ degradation of coal by water. The elastic modulus and peak strength of water-immersed coal decrease exponentially with the immersion time, while the creep rate of coal shows an upward tendency with the promoted immersion time. According to the remarked relationships of elastic, viscoelastic, and viscoplastic properties versus the stress levels and water-immersion time, a creep model based on conformable fractional derivatives is proposed, considering the influence of the water-immersion time and variable stress level. The proposed model was verified using the experiment data, showing a good capacity of the creep model for reproducing the creep process of water-immersed coal. This paper provides a fundamental model for further studying the stability of coal pillars and their influence on the safety of underground water reservoirs. Full article

Brown rot of stone fruit, caused by Monilinia spp., is one of the most important diseases worldwide, causing significant production losses. Currently, the standard practices for controlling this infection consist of repetitive use of synthetic fungicides. The global tendency encourages the demand for high-quality food products harmless to health and the environment, leading to a reduction in the use of these types of substances. Zuccagnia punctata (Fabaceae) is a perennial shrub extensively used for the treatment of fungal and bacterial infections in Argentinean traditional medicine. In this study, we isolated and characterized (morphologically and molecularly) a pathogenic and virulent strain of Monilinia fructicola, which is the most hostile species of the genus. Consequently, we explored the in vitro antifungal activity of the ethanolic extract of Z. punctata against this phytopathogen. The chalcones 2′,4′-dihydroxy-3′-methoxychalcone and 2′,4′-dihydroxychalcone were isolated from the extract and evaluated against M. fructicola demonstrating that they were responsible for this activity. To promote full-spectrum extract rather than pure compounds, we performed ex-vivo assays using fresh peaches inoculated with the pathogen, and then treated by immersion in an extract solution of 250 µg/mL concentration. Treatment with Z. punctata extract did not show a statistically significant difference from commercial fungicides in the control of fruit rot. In addition, Huh7 cell cytotoxicity evaluation showed that Z. punctata extract was less cytotoxic than commercial fungicides at the assayed concentrations. Based on our research, this plant extract could potentially offer a safer alternative to commercial fungicides for treating peach brown rot. Full article