Electrochemically converting nitrate, a widespread water pollutant, back to valuable ammonia is a green and delocalized route for ammonia synthesis, and can be an appealing and supplementary ...alternative to the Haber-Bosch process. However, as there are other nitrate reduction pathways present, selectively guiding the reaction pathway towards ammonia is currently challenged by the lack of efficient catalysts. Here we report a selective and active nitrate reduction to ammonia on Fe single atom catalyst, with a maximal ammonia Faradaic efficiency of ~ 75% and a yield rate of up to ~ 20,000 μg h
mg
(0.46 mmol h
cm
). Our Fe single atom catalyst can effectively prevent the N-N coupling step required for N
due to the lack of neighboring metal sites, promoting ammonia product selectivity. Density functional theory calculations reveal the reaction mechanisms and the potential limiting steps for nitrate reduction on atomically dispersed Fe sites.
Abstract
Oxygen reduction reaction towards hydrogen peroxide (H
2
O
2
) provides a green alternative route for H
2
O
2
production, but it lacks efficient catalysts to achieve high selectivity and ...activity simultaneously under industrial-relevant production rates. Here we report a boron-doped carbon (B-C) catalyst which can overcome this activity-selectivity dilemma. Compared to the state-of-the-art oxidized carbon catalyst, B-C catalyst presents enhanced activity (saving more than 210 mV overpotential) under industrial-relevant currents (up to 300 mA cm
−2
) while maintaining high H
2
O
2
selectivity (85–90%). Density-functional theory calculations reveal that the boron dopant site is responsible for high H
2
O
2
activity and selectivity due to low thermodynamic and kinetic barriers. Employed in our porous solid electrolyte reactor, the B-C catalyst demonstrates a direct and continuous generation of pure H
2
O
2
solutions with high selectivity (up to 95%) and high H
2
O
2
partial currents (up to ~400 mA cm
−2
), illustrating the catalyst’s great potential for practical applications in the future.
The increased availability of smartphone and mobile gadgets has transformed the tourism industry and will continue to enhance the ways in which tourists access information while traveling. Augmented ...reality has grown in popularity because of its enhanced mobile capabilities. In tourism research, few attempts have been made to assess user satisfaction with augmented reality applications and the behavioral intention to recommended them. This study uses a quality model to test users' satisfaction and intention to recommend marker-based augmented reality applications. By applying process theory, this study also investigates the differences in these constructs between high- and low-innovativeness groups visiting a theme park in Jeju Island, South Korea. Questionnaires administered to 241 theme park visitors revealed that content, personalized service, and system quality affect users' satisfaction and intention to recommend augmented reality applications. In addition, personal innovativeness was found to reinforce the relationships among content quality, personalized service quality, system quality, and satisfaction with augmented reality.
•Tourists' augmented reality perception was measured by the lens of modified DeLone & McLean's Model.•The higher level of personal innovativeness, the more important the role of AR system quality.•The lower level of personal innovativeness, the more important the role of AR contents quality.•Our findings explain which quality factors are important for AR satisfaction and loyalty.
Although virtual reality (VR) is an emerging technology in tourism, little research has been conducted on what factors make consumers visit destinations presented by VR. To address this gap in the ...literature, this study developed a theoretical framework including authentic experience, cognitive and affective responses, attachment, and visit intention with VR tourism using a stimulus-organism-response (SOR) theory. The results revealed significant impacts of authentic experience on cognitive and affective responses, indicating that authentic experience is an important factor in VR tourism. The study identified cognitive and affective responses as significant mediators in predicting attachment and visit intention. The results demonstrated that the intention to visit places shown in VR tourism was influenced by attachment to VR. Cognitive response had a stronger influence than affective response on the intention to visit a destination in VR. This study sheds light on why potential tourists visit destinations shown in VR.
Transition-metal single-atom catalysts present extraordinary activity per metal atomic site, but suffer from low metal-atom densities (typically less than 5 wt% or 1 at.%), which limits their overall ...catalytic performance. Here we report a general method for the synthesis of single-atom catalysts with high transition-metal-atom loadings of up to 40 wt% or 3.8 at.%, representing several-fold improvements compared to benchmarks in the literature. Graphene quantum dots, later interweaved into a carbon matrix, were used as a support, providing numerous anchoring sites and thus facilitating the generation of high densities of transition-metal atoms with sufficient spacing between the metal atoms to avoid aggregation. A significant increase in activity in electrochemical CO2 reduction (used as a representative reaction) was demonstrated on a Ni single-atom catalyst with increased Ni loading.Transition-metal single-atom catalysts display excellent activity per metal atom site, but suffer from low metal atom densities (typically less than 5 wt% or 1 at.%), which limits their overall catalytic performance. Now, the use of a graphene-quantum-dot primary support, later interweaved into a carbon matrix, has enabled the synthesis of single-atom catalysts with high transition-metal atom loadings of up to 40 wt% or 3.84 at.%.
•The combined audio-visual presentation led to a greater recovery than the no audio condition.•The 360-degree VR led to a greater recovery than the monitor screen condition.•The rural scenes led to a ...greater recovery than the urban scene.•The view of water stream led to a greater recovery when it was presented with the sound.
This study examined the effects of aural and visual experience on psycho-physiological recovery in simulated environments. Laboratory experiments were conducted with 32 participants. Ten horror videos were used as stressor clips, while five videos depicted urban or rural settings as recovery clips. The videos were presented via VR (head-mounted display) and on a monitor screen. The effect of the audio presentation was tested by presenting the stimuli with or without sound. Psychological recovery was assessed using a set of questions (e.g., perceived preference). Physiological recovery was measured with five physiological responses (e.g., fEMG and HR) monitored throughout the experiment. It was found that the rural setting led to a better psycho-physiological recovery than the urban setting when the stimuli were presented both in the VR and Screen conditions. In particular, the rural setting with water features evoked the greatest recovery. The rural setting presented with water sound showed significant differences in psychological recovery between Audio-Visual and No-Audio conditions. Compared to the Screen condition, stimuli presented in the VR condition did not have any main effect on the psychological recovery; however, it showed main effects on some of the physiological responses. The audio presentation had significant impacts on all psychological recovery ratings but it showed an impact on only one physiological response, fEMG of the zygomatic muscle.
Background Early detection of cancer and provision of appropriate treatment can increase the cancer cure rate and reduce cancer-related deaths. Early detection requires improving the cancer screening ...quality of each medical institution and enhancing the capabilities of health professionals through tailored education in each field. However, during the COVID-19 pandemic, regional disparities in educational infrastructure emerged, and educational accessibility was restricted. The demand for remote cancer education services to address these issues has increased, and in this study, we considered medical metaverses as a potential means of meeting these needs. In 2022, we used Metaverse Educational Center, developed for the virtual training of health professionals, to train radiologic technologists remotely in mammography positioning. Objective This study aims to investigate the user experience of the Metaverse Educational Center subplatform and the factors associated with the intention for continuous use by focusing on cases of using the subplatform in a remote mammography positioning training project. Methods We conducted a multicenter, cross-sectional survey between July and December 2022. We performed a descriptive analysis to examine the Metaverse Educational Center user experience and a logistic regression analysis to clarify factors closely related to the intention to use the subplatform continuously. In addition, a supplementary open-ended question was used to obtain feedback from users to improve Metaverse Educational Center. Results Responses from 192 Korean participants (male participants: n=16, 8.3%; female participants: n=176, 91.7%) were analyzed. Most participants were satisfied with Metaverse Educational Center (178/192, 92.7%) and wanted to continue using the subplatform in the future (157/192, 81.8%). Less than half of the participants (85/192, 44.3%) had no difficulty in wearing the device. Logistic regression analysis results showed that intention for continuous use was associated with satisfaction (adjusted odds ratio 3.542, 95% CI 1.037-12.097; P=.04), immersion (adjusted odds ratio 2.803, 95% CI 1.201-6.539; P=.02), and no difficulty in wearing the device (adjusted odds ratio 2.020, 95% CI 1.004-4.062; P=.049). However, intention for continuous use was not associated with interest (adjusted odds ratio 0.736, 95% CI 0.303-1.789; P=.50) or perceived ease of use (adjusted odds ratio 1.284, 95% CI 0.614-2.685; P=.51). According to the qualitative feedback, Metaverse Educational Center was useful in cancer education, but the experience of wearing the device and the types and qualities of the content still need to be improved. Conclusions Our results demonstrate the positive user experience of Metaverse Educational Center by focusing on cases of using the subplatform in a remote mammography positioning training project. Our results also suggest that improving users’ satisfaction and immersion and ensuring the lack of difficulty in wearing the device may enhance their intention for continuous use of the subplatform.
Objectives/Hypothesis
Lipopolysaccharide (LPS), a key component of bacterial endotoxins, activates macrophages and triggers the release of inflammatory cytokines in mammalian tissues. Recent studies ...have shown that intratympanic injection of LPS simulates acute otitis media (AOM) and results in morphological and functional changes in the inner ear. Here we established an AOM mouse model with LPS to investigate the uptake of ototoxic gentamicin in the inner ear, and elucidated the underlying mechanism by focusing on cochlear inflammation as a result of AOM.
Study Design
Preclinical rodent animal model.
Methods
Fluorescently tagged gentamicin (GTTR) was systemically administered to mice with AOM. Iba1‐positive macrophage morphology and inner ear cytokine profile were evaluated by immunofluorescence technique and a mouse cytokine array kit, respectively.
Results
We observed characteristic symptoms of AOM in the LPS‐treated ears with elevated hearing thresholds indicating a conductive hearing loss. More importantly, the LPS‐induced AOM activated cochlear inflammatory responses, manifested by macrophage infiltration, particularly in the organ of Corti and the spiral ligament, in addition to the up‐regulation of proinflammatory cytokines. Meanwhile, GTTR uptake in the stria vascularis and sensory hair cells from all the LPS‐treated ears was significantly enhanced at 24, 48, and 72‐hour post‐treatment, as the most prominent enhancement was observed in the 48‐hour group.
Conclusion
In summary, this study suggests that the pathological cochlea is more susceptible to ototoxic drugs, including aminoglycosides, and justified the clinical concern of aminoglycoside ototoxicity in the AOM treatment. Laryngoscope, 131:E2573–E2582, 2021
Current clinical tests for middle ear (ME) injuries and related conductive hearing loss (CHL) are lengthy and costly, lacking the ability to noninvasively evaluate both structure and function in real ...time. Optical coherence tomography (OCT) provides both, but its application to the audiological clinic is currently limited.
Adapt and use a commercial Spectral-Domain OCT (SD-OCT) to evaluate anatomy and sound-evoked vibrations of the tympanic membrane (TM) and ossicles in the human ME.
SD-OCT was used to capture high-resolution three-dimensional (3D) ME images and measure sound-induced vibrations of the TM and ossicles in fresh human temporal bones.
The 3D images provided thickness maps of the TM. The system was, with some software adaptations, also capable of phase-sensitive vibrometry. Measurements revealed several modes of TM vibration that became more complex with frequency. Vibrations were also measured from the incus, through the TM. This quantified ME sound transmission, which is the essential measure to assess CHL.
We adapted a commercial SD-OCT to visualize the anatomy and function of the human ME. OCT has the potential to revolutionize point-of-care assessment of ME disruptions that lead to CHL which are otherwise indistinguishable via otoscopy.
PDF
