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Energy conversion from the environment into electricity is the most direct and effective electricity source to sustainably power off-grid electronics, once the electricity requirement exceeds the capability of traditional centralized power supply systems. Normally photovoltaic cells have enabled distributed power generation during the day, but do not work at night. Thus, efficient electricity generation technologies for a sustainable all-day power supply with no necessity for energy storage remain a challenge. Herein, an innovative all-day power generation strategy is reported, which self-adaptively integrates the diurnal photothermal and nocturnal radiative cooling processes into the thermoelectric generator (TEG) via the spectrally dynamic modulated coating, to continuously harvest the energy from the hot sun and the cold universe for power generation. Synergistic with the optimized latent heat phase change material, the electricity generation performance of the TEG is dramatically enhanced, with a maximum power density exceeding 1000 mW m-2 during the daytime and up to 25 mW m-2 during the nighttime, corresponding to an improvement of 123.1% and 249.1%, compared with the conventional strategy. This work maximizes the utilization of ambient energy resources to provide an environmentally friendly and uninterrupted power generation strategy. This opens up new possibilities for sustained power generation both daytime and nighttime.
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Mass storage and removal in solids always play a vital role in technological applications such as modern batteries and neuronal computations. However, they were kinetically limited by the slow diffusional process in the lattice, which made it challenging to fabricate applicable conductors with high electronic and ionic conductivities at room temperature. Here, we proposed an acid solution/WO3/ITO sandwich structure and achieved ultrafast H transport in the WO3 layer by interfacial job-sharing diffusion, which means the spatially separated transport of the H+ and e- in different layers. From the color change of WO3, the effective diffusion coefficient (Deff) was estimated, dramatically increasing ≤106 times and overwhelming values from previous reports. The experiments and simulations also revealed the universality of extending this approach to other atoms and oxides, which could stimulate systematic studies of ultrafast mixed conductors in the future.
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OBJECTIVE: We aimed to investigate the neural mechanisms underlying the inhibitory function performance of maritime Search and Rescue (SAR) personnel in states of physical exhaustion. BACKGROUND: SAR missions pose serious challenges to the cognitive function of SAR personnel, especially in extreme environments and physical exhaustion. It is important to understand SAR personnel's cognitive performance and neural activity under exhaustion to improve the efficiency of task execution and ensure work safety. METHOD: Twenty-six maritime SAR personnel were recruited to simulate boat operations until they reached a self-imposed state of exhaustion. The exhaustion state was monitored by maximum heart rate and subjective fatigue scale. Two event-related potentials, N200 and P300, were measured during a Go-Nogo task before and after a session of acute exhaustive tasks. RESULTS: After exhaustion, a marked reduction in accuracy, a notable increase in N200 amplitude, and a substantial decline in P300 amplitude under the Nogo condition were observed compared to the baseline phase. Pre- and post-exhaustion comparisons using standardized low-resolution brain electromagnetic tomography revealed reduced activations in the right middle temporal gyrus's N200 component after exhaustion in SAR personnel during the Nogo condition. CONCLUSION: The results suggest that acute physical exhaustion significantly impacts the inhibition ability of SAR personnel, prolonging the conflict monitoring phase and weakening the response inhibition phase. These findings provide valuable insights into how physical exhaustion affects cognitive functions critical to the safety and effectiveness of SAR operations, and can inform strategies to improve training and equipment to enhance performance under extreme conditions.
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Eletroencefalografia , Potenciais Evocados , Fadiga , Inibição Psicológica , Humanos , Masculino , Adulto , Adulto Jovem , Fadiga/fisiopatologia , Potenciais Evocados/fisiologia , Frequência Cardíaca/fisiologia , Encéfalo/fisiologia , Feminino , Desempenho Psicomotor/fisiologiaRESUMO
Researchers have found that there may be a correlation between physical activity, executive function, and depression for college students with depression. However, there is limited information available regarding the relationship and interaction between subclinical depression, physical activity, and executive function among college students with subclinical depression. The purpose of this study is to assess the correlation and interaction between subclinical depression, physical activity, and executive function in female college students with subclinical depression. The ActiGraph GT3X was utilized to measure physical activity time, and the colour-word Stroop task was employed to evaluate the executive function of the participants. The findings revealed that female college students with subclinical depression had a significantly lower time for moderate-intensity physical activity compared to healthy female college students. Additionally, the subclinical depression group took significantly longer to complete the colour-word Stroop task compared to the healthy group of female college students. The results of correlation and mediation analyses suggest a negative correlation between BDI-II scores and physical activity time and executive function in female college students with subclinical depression. Moreover, executive function appears to play a partial mediating role in the relationship between physical activity and subclinical depression.
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Although exercise training has been shown to enhance neurological function, there is a shortage of research on how exercise training affects the temporal-spatial synchronization properties of functional networks, which are crucial to the neurological system. This study recruited 23 professional and 24 amateur dragon boat racers to perform simulated paddling on ergometers while recording EEG. The spatiotemporal dynamics of the brain were analyzed using microstates and omega complexity. Temporal dynamics results showed that microstate D, which is associated with attentional networks, appeared significantly altered, with significantly higher duration, occurrence, and coverage in the professional group than in the amateur group. The transition probabilities of microstate D exhibited a similar pattern. The spatial dynamics results showed the professional group had lower brain complexity than the amateur group, with a significant decrease in omega complexity in the α (8-12 Hz) and ß (13-30 Hz) bands. Dragon boat training may strengthen the attentive network and reduce the complexity of the brain. This study provides evidence that dragon boat exercise improves the efficiency of the cerebral functional networks on a spatiotemporal scale.
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Encéfalo , Eletroencefalografia , Humanos , Masculino , Eletroencefalografia/métodos , Encéfalo/fisiologia , Adulto , Adulto Jovem , Exercício Físico/fisiologia , Esportes Aquáticos/fisiologia , Atenção/fisiologia , FemininoRESUMO
As the fields of photonics and information technology develop, a lot of novel applications based on VO2 material, such as optoelectronic computing and information encryption, have been developed. While the performance of these devices was not only closely associated with the VO2 phase transition properties but also depended on their dimensional characteristics. In the current study, we conducted the dimension-controlled vanadium dioxide (VO2) film growth, resulting in the epitaxial 2-dimensional (2D) VO2 film and well-distributed 3-dimensional (3D) VO2 crystal film deposition, respectively. It was revealed that, unlike the 2D film, the pronounced localized surface plasmon resonance dominated the near-infrared spectrum across the phase transition for the 3D VO2 film due to the naturally formed meta-surface structure, which showed a transmittance valley in the infrared spectrum after metallization. Based on this distinct infrared spectrum feature in the 3D VO2 film, we proposed an optoelectronic logic gate controlled by the input voltage and the probing Vis/IR light. By detecting the transmittance states of the probing light with different wavelengths, we achieved multistate encoding functions and demonstrated the information encryption application. This new conception device also showed great potential for some other applications such as optoelectronic coupled computing, information encryption, and optical near-field sensing computing.
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The efficient generation and active modulation of terahertz (THz) waves are strongly required for the development of various THz applications such as THz imaging/spectroscopy and THz communication. In addition, due to the increasing degree of integration for the THz optoelectronic devices, miniaturizing the complex THz system into a compact unit is also important and necessary. Today, integrating the THz source with the modulator to develop a powerful, easy-to-adjust, and scalable or on-chip THz emitter is still a challenge. As a new type of THz emitter, a spintronic THz emitter has attracted a great deal of attention due to its advantages of high efficiency, ultrawide band, low cost, and easy integration. In this study, we have proposed a multifield-modulated spintronic THz emitter based on the VO2/Ni/Pt multilayer film structure with a wide band region of 0-3 THz. Because of the pronounced phase transition of the integrated VO2 layer, the fabricated THz emitter can be efficiently modulated via thermal or electric stimuli with a modulation depth of about one order of magnitude; the modulation depths under thermal stimulation and electrical stimulation were 91.8% and 97.3%, respectively. It is believed that this multifield modulated spintronic THz emitter will provide various possibilities for the integration of next-generation on-chip THz sources and THz modulators.
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Introduction: Various approaches have been used to explore different aspects of the regulation of brain activity by acute exercise, but few studies have been conducted on the effects of acute exercise fatigue on large-scale brain functional networks. Therefore, the present study aimed to explore the effects of acute exercise fatigue on resting-state electroencephalogram (EEG) microstates and large-scale brain network rhythm energy. Methods: The Bruce protocol was used as the experimental exercise model with a self-controlled experimental design. Thirty males performed incremental load exercise tests on treadmill until exhaustion. EEG signal acquisition was completed before and after exercise. EEG microstates and resting-state cortical rhythm techniques were used to analyze the EEG signal. Results: The microstate results showed that the duration, occurrence, and contribution of Microstate C were significantly higher after exhaustive exercise (p's < 0.01). There was a significantly lower contribution of Microstate D (p < 0.05), a significant increase in transition probabilities between Microstate A and C (p < 0.05), and a significant decrease in transition probabilities between Microstate B and D (p < 0.05). The results of EEG rhythm energy on the large-scale brain network showed that the energy in the high-frequency ß band was significantly higher in the visual network (p < 0.05). Discussion: Our results suggest that frequently Microstate C associated with the convexity network are important for the organism to respond to internal and external information stimuli and thus regulate motor behavior in time to protect organism integrity. The decreases in Microstate D parameters, associated with the attentional network, are an important neural mechanism explaining the decrease in attention-related cognitive or behavioral performance due to acute exercise fatigue. The high energy in the high-frequency ß band on the visual network can be explained in the sense of the neural efficiency hypothesis, which indicates a decrease in neural efficiency.
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Objective:To investigate the efficacy of functional endoscopic sinus surgeryï¼FESSï¼ in the treatment of olfactory dysfunction in patients with chronic rhinosinusitis with nasal polyps ï¼CRSwNPï¼ , at the same time, it provides an evidence for the prognosis evaluation of olfaction and the clinical application of oERPs to evaluate the plasticity of olfaction cortex. Methods:From October 2021 to October 2022, 45 patients with CRSwNP who underwent FESS nine-step standardized treatment in our department were recruited as the research subjects, divided into 22 patients with eosinophilic CRSwNPï¼ECRSï¼and 23 patients with non-eosinophilic CRSwNPï¼nECRSï¼. VAS-olfactory dysfunction ï¼VAS-ODï¼ score, SNOT-22 olfactory score, Sniffin' Sticks test and oERPs collection and processing were performed before the operation. All items were evaluated again 3 months after the operation. Results:VAS-OD and SNOT-22 olfactory score were significantly lower in all CRSwNP patients after the operation than those before the operation[Fï¼1, 43ï¼ =357.429, P<0.001; Fï¼1, 43ï¼ =185.657, P<0.001], the scores of T, D, I and TDI scores in Sniffin' Sticks test were significantly higher than those before the operation[Fï¼1, 43ï¼ =126.302, P<0.001; Fï¼1, 43ï¼ =311.301, P<0.001; Fï¼1, 43ï¼ =131.401, P<0.001; Fï¼1, 43ï¼ =295.885, P<0.001]; The decrease of VAS-OD and SNOT-22 olfactory score in the ECRS group was smaller than that in the nECRS group[Fï¼1, 43ï¼ =4.825, P=0.033; Fï¼1, 43ï¼ =9.916, P=0.003], T, D and TDI scores were significantly lower in nECRS group than those in nECRS group[Fï¼1, 43ï¼ =6.719, P=0.013; Fï¼1, 43ï¼ =4.890, P=0.032; Fï¼1, 43ï¼ =4.469, P=0.040]; There was a positive correlation between preoperative eosinophil-to-lymphocyte ratioï¼ELRï¼ and SNOT-22 olfactory score and how much it changesï¼r=0.455, P=0.002; r=-0.414, P=0.005ï¼, a negative correlation between T, TDI score and how much they change respectivelyï¼r=-0.431, P=0.003; r=-0.385, P=0.009; r=-0.383, P=0.010; r=-0.316, P=0.035ï¼. The latency of P3 was significantly shorter after operation than that before operation in all CRSwNP patients[Fï¼1, 14ï¼ =24.840, P<0.001], however, the amplitude has no significant surgical effect. Conclusion:FESS could significantly improve the olfactory function of CRSwNP patients, while changes in plasticity may occur in the olfactory cortex. In addition, the preoperative peripheral blood eosinophil granulocyte level can predict the postoperative olfactory improvement.
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Pólipos Nasais , Transtornos do Olfato , Rinite , Sinusite , Humanos , Estudos Prospectivos , Pólipos Nasais/complicações , Pólipos Nasais/cirurgia , Rinite/complicações , Rinite/cirurgia , Sinusite/complicações , Sinusite/cirurgia , Transtornos do Olfato/etiologia , Doença Crônica , Endoscopia/efeitos adversosRESUMO
In the information explosion society, information security is highly demanded in the practical application, which raised a surge of interest in designing secure and reliable information transmission channels based on the inherent properties of emerging devices. Here, an innovative strategy to achieve the data encryption and reading during the data confidential transmission based on VO2 device is proposed. Owing to the specific insulator-to-metal transition property of VO2 , the phase transitions between the insulator and metallic states are modulated by the combination of electric field, temperature, and light radiation. These external stimulus-induced phase diagram is directly associated with the defined VO2 device, which are applicable for control the "0" or "1" electrical logic state for the information encryption. A prototype device is fabricated on an epitaxial VO2 film, which displayed a unique data encryption function with excellent stability. The current study not only demonstrated a multiphysical field-modulated VO2 device for information encryption, but also supplied some clues for functional devices applications in other correlated oxide materials.
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Extensive use of renewable and clean energy is one of the promising ways to solve energy/environmental problems and promote the sustainable development of our society. As inexhaustible energy sources, the photothermal (PT) and radiative cooling (RC) energy from the sun and outer space have recently attracted tremendous interest. However, these two kinds of energy utilization have distinctly opposite spectral properties, especially in the infrared range, making it extremely difficult to integrate these two energy harvesting modes within a fixed device for continuous energy collection. Thus, in the current study, we have proposed a spectrally self-adaptive broadband absorber/emitter (SSBA/E) based on vanadium dioxide (VO2), a typical phase transition material, to achieve continuous energy harvesting via collecting solar thermal energy in PT mode during the day and obtaining cool energy in wide-band RC mode at night. Experimental results show that owing to the phase transition property of the VO2 layer, these two energy collection modes can be adaptively switched. Specifically, the VO2-based device shows a broadband infrared emissivity modulation from 0.21 to 0.75 and low critical temperatures (58.4 and 49.2 °C) during the phase transition, leading to continuous energy harvesting with high efficiency. Due to the broadband infrared emission, the RC maximum power of the SSBA/E device was estimated to be 58 W m-2. The proposed VO2 smart coatings are also applicable for many other applications such as thermal management of spacecraft, infrared camouflage, or adaptive optical devices.
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This study aimed to investigate the association between complex brain functional networks and the metabolites in urine in subclinical depression. Electroencephalography (EEG) signals were recorded from 78 female college students, including 40 with subclinical depression (ScD) and 38 healthy controls (HC). The phase delay index was utilized to construct functional connectivity networks and quantify the topological properties of brain networks using graph theory. Meanwhile, the urine of all participants was collected for non-targeted LC-MS metabolic analysis to screen differential metabolites. The global efficiency was significantly increased in the α-2, ß-1, and ß-2 bands, while the characteristic path length of ß-1 and ß-2 and the clustering coefficient of ß-2 were decreased in the ScD group. The severity of depression was negatively correlated with the level of cortisone (p = 0.016, r = -0.40). The metabolic pathways, including phenylalanine metabolism, phenylalanine tyrosine tryptophan biosynthesis, and nitrogen metabolism, were disturbed in the ScD group. The three metabolic pathways were negatively correlated (p = 0.014, r = -0.493) with the global efficiency of the brain network of the ß-2 band, whereas they were positively correlated (p = 0.014, r = 0.493) with the characteristic path length of the ß-2 band. They were mainly associated with low levels of L-phenylalanine, and the highest correlation sparsity was 0.11. The disturbance of phenylalanine metabolism and the phenylalanine, tryptophan, tyrosine biosynthesis pathways cause depressive symptoms and changes in functional brain networks. The decrease in the L-phenylalanine level may be related to the randomization trend of the ß-1 frequency brain functional network.
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Depressão , Triptofano , Encéfalo , Eletroencefalografia , Feminino , Humanos , Fenilalanina , TirosinaRESUMO
Studies have found that the prevalence of chronic fatigue syndrome (CFS) in adolescents has continued to increase over the years, affecting learning and physical health. High school is a critical stage for adolescents to grow and mature. There are inadequate detection and rehabilitation methods for CFS due to an insufficient understanding of the physiological mechanisms of CFS. The purpose of this study was to evaluate the effect and metabolic mechanisms of an aerobic running intervention program for high school students with CFS. Forty-six male high school students with CFS were randomly assigned to the exercise intervention group (EI) and control group (CFS). Twenty-four age- and sex-matched healthy male students were recruited as healthy controls (HCs). The EI group received the aerobic intervention for 12 weeks, three times a week, in 45-min sessions; the CFS group maintained their daily routines as normal. The outcome measures included fatigue symptoms and oxidation levels. Keratin was extracted from the nails of all participants, and the oxidation level was assessed by measuring the content of 3-Nitrotyrosine (3-NT) in the keratin by ultraviolet spectrophotometry. All participants' morning urine was collected to analyze urinary differential metabolites by the GC-MS technique before and after the intervention, and MetaboAnalyst 5.0 was used for pathway analysis. Compared with before the intervention, the fatigue score and 3-NT level in the EI group were significantly decreased after the intervention. The CFS group was screened for 20 differential metabolites involving the disruption of six metabolic pathways, including arginine biosynthesis, glycerolipid metabolism, pentose phosphate pathway, purine metabolism, ß-alanine metabolism, and arginine and proline metabolism. After the intervention, 21 differential metabolites were screened, involved in alterations in three metabolic pathways: beta-alanine metabolism, pentose phosphate metabolism, and arginine and proline metabolism. Aerobic exercise was found to lessen fatigue symptoms and oxidative levels in students with CFS, which may be related to the regulation of putrescine (arginine and proline metabolism), 6-Phospho-D-Gluconate (starch and sucrose metabolism pathway), and Pentose (phosphate metabolism pathway).
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Síndrome de Fadiga Crônica , Adolescente , Exercício Físico , Cromatografia Gasosa-Espectrometria de Massas , Nível de Saúde , Humanos , Masculino , Redes e Vias MetabólicasRESUMO
Synchronization of the dynamic processes in structural networks connect the brain across a wide range of temporal and spatial scales, creating a dynamic and complex functional network. Microstate and omega complexity are two reference-free electroencephalography (EEG) measures that can represent the temporal and spatial complexities of EEG data. Few studies have focused on potential brain spatiotemporal dynamics in the early stages of depression to use as an early screening feature for depression. Thus, this study aimed to explore large-scale brain network dynamics of individuals both with and without subclinical depression, from the perspective of temporal and spatial dimensions and to input them as features into a machine learning framework for the automatic diagnosis of early-stage depression. To achieve this, spatio-temporal dynamics of rest-state EEG signals in female college students (n = 40) with and without (n = 38) subclinical depression were analyzed using EEG microstate and omega complexity analysis. Then, based on differential features of EEGs between the two groups, a support vector machine was utilized to compare performances of spatio-temporal features and single features in the classification of early depression. Microstate results showed that the occurrence rate of microstate class B was significantly higher in the group with subclinical depression when compared with the group without. Moreover, the duration and contribution of microstate class C in the subclinical group were both significantly lower than in the group without subclinical depression. Omega complexity results showed that the global omega complexity of ß-2 and γ band was significantly lower for the subclinical depression group compared with the other group (p < 0.05). In addition, the anterior and posterior regional omega complexities were lower for the subclinical depression group compared to the comparison group in α-1, ß-2 and γ bands. It was found that AUC of 81% for the differential indicators of EEG microstates and omega complexity was deemed better than a single index for predicting subclinical depression. Thus, since temporal and spatial complexity of EEG signals were manifestly altered in female college students with subclinical depression, it is possible that this characteristic could be adopted as an early auxiliary diagnostic indicator of depression.
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Mapeamento Encefálico , Depressão , Encéfalo , Mapeamento Encefálico/métodos , Eletroencefalografia/métodos , Feminino , Humanos , EstudantesRESUMO
At the end of 2019, Wuhan, Hubei Province, China, experienced the ravages of Coronavirus disease 2019 (COVID-19). In a few months, infected people rose to tens of thousands. This study aimed to explore the mental health status of military nurse personnel assisting (non-Hubei area) in the fight against COVID-19 and local nurse personnel (in the Wuhan area), as well as the differences in mental health status between nurses and COVID-19 patients that provide a reference basis for psychological crisis intervention. A convenience sampling method was used to select frontline nurses and COVID-19 patients (sample size 1,000+) from two mobile cabin hospitals from January to March 2020. The questionnaire consists of socio-demographic information, Patient Health Questionnaire 9 (PHQ-9), Generalized Anxiety Disorder 7 (GAD-7), General Mental Health Service Questionnaire and Work Intensity and Physical Status Questionnaire. The results showed that depression was present in 117 nurses (19.73%) and 101 patients (23.33%) with PHQ-9 scores >10; anxiety was present in 60 nurses (10.12%) and 54 patients (12.47%) with GAD-7 >10. The anxiety and depression levels of nurses in Wuhan area were higher than those in non-Hubei area. The differences in PHQ-9 and GAD-7 scores were also statistically significant (p < 0.001) when comparing patients from different regions, with anxiety and depression rates of 30.19 and 16.04% in local patients and 16.74 and 9.50% in foreign patients. The comparison between nurses and patients showed that the nurses were more depressed than the patients, while the patients were more anxious. Local nurses in Wuhan had a higher workload intensity than aid nurses (77.72 vs. 57.29%). Over 95% of frontline nurses and patients reported that they had not received any form of psychological counseling before the COVID-19 outbreak. 12.87% (26/194) of frontline nurses in Wuhan had a history of taking hypnotic drugs. However, fewer patients (16/212, 7.55%) took medication than frontline nurses. Anxiety and depression levels were far higher among local nurses and patients in Wuhan than in non-Hubei areas. The nurses had higher levels of depression, while the patients had higher anxiety levels. Providing targeted mental health services to healthcare professionals and patients is necessary when experiencing the impact of a major event.
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COVID-19 , Ansiedade/epidemiologia , Ansiedade/psicologia , Transtornos de Ansiedade/epidemiologia , COVID-19/epidemiologia , Estudos Transversais , Depressão/epidemiologia , Depressão/psicologia , Nível de Saúde , Humanos , SARS-CoV-2RESUMO
The electrochromic WO3 smart window based on an aqueous electrolyte shows an excellent liquid/solid interface and thus can achieve a fast electrochromic response, while the aqueous electrolyte has a limited electrochemical window, which probably induces the H+ reduction and degrades the practical application. Here, we propose a strategy to modify the traditional Li+ acidic aqueous electrolyte by adding some selective inert metal ions, which not only improve the electrochromic performance but also avoid the possible production of hydrogen bubbles due to the broadened electrochemical window. Furthermore, reversible electroplating of inert metal ions will occur, leading to an enhanced optical transmission change of up to 77.5% at 500 nm and 70.4% at 700 nm. This combination of Li-ion insertion and metal electroplating in the ESW device makes it superior to all of the previous reports. The device also demonstrates high stability and high electrochromic efficiency after 1000 cycles. The current study not only emphasizes the rational design for aqueous electrolytes but also demonstrates a practical way to realize an excellent electrochromic window for practical applications.
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Sleep staging is the basis of sleep assessment and plays a crucial role in the early diagnosis and intervention of sleep disorders. Manual sleep staging by a specialist is time-consuming and is influenced by subjective factors. Moreover, some automatic sleep staging algorithms are complex and inaccurate. The paper proposes a single-channel EEG-based sleep staging method that provides reliable technical support for diagnosing sleep problems. In this study, 59 features were extracted from three aspects: time domain, frequency domain, and nonlinear indexes based on single-channel EEG data. Support vector machine, neural network, decision tree, and random forest classifier were used to classify sleep stages automatically. The results reveal that the random forest classifier has the best sleep staging performance among the four algorithms. The recognition rate of the Wake phase was the highest, at 92.13%, and that of the N1 phase was the lowest, at 73.46%, with an average accuracy of 83.61%. The embedded method was adopted for feature filtering. The results of sleep staging of the 11-dimensional features after filtering show that the random forest model achieved 83.51% staging accuracy under the condition of reduced feature dimensions, and the coincidence rate with the use of all features for sleep staging was 94.85%. Our study confirms the robustness of the random forest model in sleep staging, which also represents a high classification accuracy with appropriate classifier algorithms, even using single-channel EEG data. This study provides a new direction for the portability of clinical EEG monitoring.
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Eletroencefalografia , Fases do Sono , Algoritmos , Eletroencefalografia/métodos , Sono , Máquina de Vetores de SuporteRESUMO
The utilization of clean hydrogen energy is becoming more feasible for the sustainable development of this society. Considering the safety issues in the hydrogen production, storage, and utilization, a sensitive hydrogen sensor for reliable detection is essential and highly important. Though various gas sensor devices are developed based on tin oxide, tungsten trioxide, or other oxides, the relatively high working temperature, unsatisfactory response time, and detection limitation still affect the extensive applications. In the current study, an amorphous tungsten trioxide (a-WO3 ) layer is deposited on a phase-change vanadium dioxide film to fabricate a phase transition controlled Pd/a-WO3 /VO2 hydrogen sensor for hydrogen detection. Results show that both the response time and sensitivity of the hydrogen sensor are improved greatly if increasing the working temperature over the transition temperature of VO2 . Theoretical calculations also reveal that the charge transfer at VO2 /a-WO3 interface becomes more pronounced once the VO2 layer transforms to the metal state, which will affect the migration barrier of H atoms in a-WO3 layer and thus improve the sensor performance. The current study not only realizes a hydrogen sensor with ultrahigh performance based on VO2 layer, but also provides some clues for designing other gas sensors with phase-change material.
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This study investigates the changes in soldiers' brain executive function at different altitude environments and their relationship with blood oxygen saturation. Stratified sampling was conducted in different altitude 133 active-duty soldiers who were stationed in Weinan (347 m, n = 34), Nyingchi (2,950 m, n = 32), Lhasa (3,860 m, n = 33), and Nagqu (4,890 m, n = 34) for 2 years. The Go/NoGo paradigm with event-related potentials (ERPs) and event-related oscillations (EROs) was used to explore the time and neural oscillation courses of response inhibition. Behavioral results revealed that at the 4,890-m altitude area, the soldiers had the highest false alarm rate, the longest reaction time, and the slowest information transmission rate. The electrophysiological results revealed that NoGo-N2 and N2d decreased with increasing altitude, with significant changes at 3,860 m; the amplitudes of NoGo-P3 and P3d in plateau groups were significantly more negative than the plain and changed significantly at 2,950 m. The results of correlation analysis showed that NoGo-P3 was negatively correlated with altitude (r = -0.358, p = 0.000), positively correlated with SpO2 (r = 0.197, p = 0.041) and information translation rate (ITR) (r = 0.202, p = 0.036). P3d was negatively correlated with altitude (r = -0.276, p = 0.004) and positively correlated with ITR (r = 0.228, p = 0.018). N2d was negatively correlated with ITR (r = 0.204, p = 0.034). The power spectrum analysis of NoGo-N2 and NoGo-P3 showed that the power of δ and θ bands at the plateau area was significantly lower than the plain area and showed a significant step-by-step decrease; the α-band power increases significantly only in the area of 4,890 m. The effect of chronic hypoxia exposure at different altitudes of the plateau on the response inhibition of soldiers was manifested: 3,860 m was the altitude at which the brain response inhibition function decreased during the conflict monitoring stage, and 2,950 m was the altitude at which it dropped during the response inhibition stage. In addition, the soldier's brain's executive function was closely related to SpO2, and a reduction in SpO2 may lead to a decline in response inhibition.
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The EEG features of different emotions were extracted based on multi-channel and forehead channels in this study. The EEG signals of 26 subjects were collected by the emotional video evoked method. The results show that the energy ratio and differential entropy of the frequency band can be used to classify positive and negative emotions effectively, and the best effect can be achieved by using an SVM classifier. When only the forehead and forehead signals are used, the highest classification accuracy can reach 66%. When the data of all channels are used, the highest accuracy of the model can reach 82%. After channel selection, the best model of this study can be obtained. The accuracy is more than 86%.