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Tunability is a fundamental prerequisite for functional devices and forms the backbone of reconfigurable microwave photonic (MWP) signal processors. In this paper, we explore the use of indium tin oxide (ITO) thin films, notable for their combination of optical transparency and electrical conductivity, to provide tunability for integrated MWP devices. We study the impacts of post-thermal annealing on the structural, electrical, and optical properties of ITO films. The annealed ITO microheater maintains a low total insertion loss of just 0.1â dB while facilitating the tunability of the microring across the entire free spectral range (FSR) using less than half the voltage required by its non-annealed counterpart. Furthermore, the post-annealed ITO film exhibits a 30% improvement in response time, enhancing its performance as an active voltage-controlled microheater. Leveraging this advantage, we employed the post-annealed device to demonstrate continuous tunable radio frequency (RF) phase shifts from 0-330° across a frequency range spanning 15â GHz to 40â GHz with only 5.58â mW of power. The flexibility in modifying the ITO thin film properties effectively bridges the gap between achieving low-loss and high-speed thermo-optic based microheaters.
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Polycyclic aromatic hydrocarbons (PAHs) are of significant public concern because of their toxicity and long-range transport potential. Extensive studies have been conducted to explore the source-receptor relationships of PAHs via atmospheric transport. However, the transfer of trade-driven regional and global PAHs is poorly understood. This study estimated the virtual PAHs emission transfer embodied in global trade from 2004 to 2014 and simulated the impact of international trade on global contamination and associated human inhalation exposure risk of PAHs. Results show that trade-driven PAHs flowed primarily from developed to less-developed regions, particularly in those regions with intensive heavy industries and transportation. As the result, international trade resulted in an increasing risk of lung cancer induced by exposure to PAHs (27.8% in China, 14.7% in India, and 11.3% in Southeast Asia). In contrast, we found decreasing risks of PAHs-induced lung cancer in Western Europe (63.2%) and the United States (45.9%) in 2004. Our findings indicate that final demand and emission intensity are the key driving factors contributing to rising and falling consumption-based PAHs emissions and related health risk respectively. The results could provide a useful reference for global collaboration in the reduction of PAHs pollution and related health risks.
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Poluentes Atmosféricos , Neoplasias Pulmonares , Hidrocarbonetos Policíclicos Aromáticos , Humanos , Poluentes Atmosféricos/análise , Exposição por Inalação/análise , Comércio , Internacionalidade , China , Monitoramento Ambiental/métodos , Medição de RiscoRESUMO
The long-range magnetic ordering in frustrated magnetic systems is stabilized by coupling magnetic moments to various degrees of freedom, for example, by enhancing magnetic anisotropy via lattice distortion. Here, the unconventional spin-lattice coupled metamagnetic properties of atomically-thin CrOCl, a van der Waals antiferromagnet with inherent magnetic frustration rooted in the staggered square lattice, are reported. Using temperature- and angle-dependent tunneling magnetoconductance (TMC), in complementary with magnetic torque and first-principles calculations, the antiferromagnetic (AFM)-to-ferrimagnetic (FiM) metamagnetic transitions (MTs) of few-layer CrOCl are revealed to be triggered by collective magnetic moment flipping rather than the established spin-flop mechanism, when external magnetic field (H) enforces a lattice reconstruction interlocked with the five-fold periodicity of the FiM phase. The spin-lattice coupled MTs are manifested by drastic jumps in TMC, which show anomalous upshifts at the transition thresholds and persist much higher above the AFM Néel temperature. While the MTs exhibit distinctive triaxial anisotropy, reflecting divergent magnetocrystalline anisotropy of the c-axis AFM ground state, the resulting FiM phase has an a-c easy plane in which the magnetization axis is freely rotated by H. At the 2D limit, such a field-tunable FiM phase may provide unique opportunities to explore exotic emergent phenomena and novel spintronics devices.
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In order to demonstrate the formation of laser-induced periodic surface structures (LIPSS), simulations were performed to investigate the effect of multiple femtosecond laser pulses with different laser energy densities on a Ti6Al4V surface. In this work, a set of partial differential equations calculating the electron and lattice temperature variations, followed by coupling with an electric field, is used to analyze the evolution of the periodic surface structure induced by the interaction of the femtosecond laser with the material. As the number of pulses increases, the surface structure of the material changes from none to produce LIPSS structure and from low spatial frequency LIPSS (LSFL) structure to high spatial frequency LIPSS (HSFL) structure. In order to compare the results, single-point laser scanning ablation experiments were carried out at femtosecond laser energy. The experimental results are consistent with the simulation results.
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The pollution of heavy metals in soil caused by exposed coal gangue and its prevention and control has become a hot issue restricting the green mining of coal in China. Nemerow integrated pollution index (NIPI), potential ecological risk index (RI) and human health risk assessment model were used to evaluate the pollution and risk of heavy metals (Cu, Cr, As, Pb) in the soil around the typical coal gangue hill in Fengfeng mining area of China. The results show that: firstly, the accumulation of coal gangue leads to the enrichment of four heavy metals in the surrounding shallow soil, and NIPI and RI were 1.0-4.4 and 21.63-91.28, respectively. The comprehensive pollution level of heavy metals in soil reached the warning line and above, and the potential ecological risk level reached slightly and above. When the horizontal distance exceeded 300 m, 300 m and 200 m, respectively, the influence of coal gangue hill on the heavy metal content in shallow soil, the comprehensive pollution level of heavy metals and the potential ecological risk level basically disappeared. In addition, based on the potential ecological risk assessment results and main risk factors, the ecological risk configuration of the study area was divided into five categories: "strong ecological risk + As," "intermediate ecological risk + As + Cu," "intermediate ecological risk + As + Cu or Pb," "minor ecological risk + As + Cu" and "minor ecological risk + As + Cu or Pb." The hazard index (HI) and total carcinogenic risk (TCR) of shallow soil polluted by heavy metals in the study area were 0.24-1.07 and 0.41 × 10-4-1.78 × 10-4, respectively, which posed non-carcinogenic and carcinogenic risks to children, but the risks were controllable. This study will help to take strategic measures to accurately control and repair the heavy metal pollution in the soil around the coal gangue hill and provide a scientific basis for solving the safe use of agricultural land and realizing the construction of ecological civilization.
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Metais Pesados , Poluentes do Solo , Criança , Humanos , Monitoramento Ambiental/métodos , Carvão Mineral , Chumbo , Poluentes do Solo/análise , Metais Pesados/toxicidade , Metais Pesados/análise , Medição de Risco , Solo , ChinaRESUMO
We present the design, fabrication, and characterization of cascaded silicon-on-insulator photonic crystal microring resonators (PhCMRRs) for dual-parameter sensing based on a multiple resonances multiple modes (MRMM) technique. Benefitting from the slow-light effect, the engineered PhCMRRs exhibit unique optical field distributions with different sensitivities via the excitation of dielectric and air modes. The multiple resonances of two distinct modes offer new possibilities for enriching the sensing receptors with additional information about environmental changes while preserving all essential properties of traditional microring resonator based sensors. As a proof of concept, we demonstrate the feasibility of extracting humidity and temperature responses simultaneously with a single spectrum measurement by employing polymethyl methacrylate as the hydrophilic coating, obtaining a relative humidity (RH) sensitivity of 3.36 pm/%RH, 5.57 pm/%RH and a temperature sensitivity of 85.9 pm/°C, 67.1 pm/°C for selected dielectric mode and air mode, respectively. Moreover, the MRMM enriched data further forges the capability to perform mutual cancellation of the measurement error, which improves the sensing performance reflected by the coefficient of determination (R2-value), calculated as 0.97 and 0.99 for RH and temperature sensing results, respectively.
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In this paper, we propose a pre-trained-combined neural network (PTCN) as a comprehensive solution to the inverse design of an integrated photonic circuit. By utilizing both the initially pre-trained inverse and forward model with a joint training process, our PTCN model shows remarkable tolerance to the quantity and quality of the training data. As a proof of concept demonstration, the inverse design of a wavelength demultiplexer is used to verify the effectiveness of the PTCN model. The correlation coefficient of the prediction by the presented PTCN model remains greater than 0.974 even when the size of training data is decreased to 17%. The experimental results show a good agreement with predictions, and demonstrate a wavelength demultiplexer with an ultra-compact footprint of 2.6×2.6µm2, a high transmission efficiency with a transmission loss of -2dB, a low reflection of -10dB, and low crosstalk around -7dB simultaneously.
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A quaternary compound with the composition Mo3ReRuC is obtained in a previously unexplored MoReRu-Mo2C system. According to X-ray structural analysis, Mo3ReRuC crystallizes in the noncentrosymmetric space group P4132 [cubic ß-Mn-type structure, a = 6.8107(1) Å]. Below 7.7 K, Mo3ReRuC becomes a bulk type-II superconductor with an upper critical field close to the Pauli paramagnetic limit. The specific heat data give a large normalized jump ΔCp/γTc = 2.3 at Tc, which points to a strongly coupled superconducting state. First-principles calculations show that its electronic states at the Fermi level are mainly contributed by Mo, Re, and Ru atoms and strongly increased by the spin-orbit coupling. Our finding suggests that the intermediate phase between alloys and carbides may be a good place to look for ß-Mn-type noncentrosymmetric superconductors.
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Increasing global and domestic food trade and required logistics create uncertainties in food safety inspection due to uncertainties in food origins and extensive trade activities. Modern blockchain techniques have been developed to inform consumers of food origins but do not provide food safety information in many cases. A novel food safety tracking and modeling framework for quantifying toxic chemical levels in the food and the food origins was developed. By integrating chemicals' multimedia environment exchange, food web, and source tracking systems, the framework was implemented to identify short-chain chlorinated paraffin (SCCP) contamination of fresh hairtail fish sold by a Walmart supermarket in Xi'an, northwestern China, and sourced in Eastern China Sea coastal waters. The framework was shown to successfully predict SCCP level with a mean of 17.8 ng g-1 in Walmart-sold hairtails, which was comparable to lab-analyzed 21.9 ng g-1 in Walmart-sold hairtails. The framework provides an alternative and cost-effective approach for safe food inspection compared to traditional food safety inspection techniques. These encouraging results suggest that the approach and rationale reported here could add additional information to the food origin tracking system to enhance transparency and consumers' confidence in the traded food they consumed.
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Hidrocarbonetos Clorados , Animais , China , Monitoramento Ambiental/métodos , Peixes , Cadeia Alimentar , Parafina/análiseRESUMO
Industry relocation under globalization has altered the origins and strength of emission sources of many air pollutants. We develop global emission inventories of polycyclic aromatic hydrocarbons (PAHs) embodied in the production and consumption of goods and services. We implement these inventories within a global atmospheric transport model and simulate spatial-temporal changes in atmospheric concentrations of benzo[α]pyrene (BaP), the most toxic congener in unsubstituted PAHs, and depositions across the Arctic subject to global trade and industry relocation. We show that interregional trade and industry relocation dramatically reduce the atmospheric levels and deposition of BaP in the Arctic. The most significant BaP decline occurs in the European and North American Arctic regions due to attenuated sources in the two well-developed continents proximate to the polar region induced by the relocation of high-PAH pollution industries to many developing countries far from the Arctic. Although BaP emissions embodied in industry relocations in China, India, and South and Southeast Asia resulted in increased BaP contamination in the Asian Arctic, such increases in pollution are minor compared to significant BaP reductions occurring in the European and North American Arctic regions. We find that "North-to-South" industry transfer could reduce trade-related BaP contamination by 60% in the Arctic.
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Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Atmosféricos/análise , Regiões Árticas , Monitoramento Ambiental/métodos , Internacionalidade , Hidrocarbonetos Policíclicos Aromáticos/análiseRESUMO
BACKGROUND: Chronic diseases are the leading causes of death and disability. With the growing patient population and climbing health care expenditures, researchers and policy makers are seeking new approaches to improve the accessibility of health information on chronic diseases while lowering costs. Online health information sources can play a substantial role in effective patient education and health communication. However, some contradictory evidence suggests that patients with chronic conditions may not necessarily seek online health information. OBJECTIVE: This study aims to integrate 2 theories (ie, the health belief model and social support theory) and a critical health literacy perspective to understand online health information seeking (OHIS) among patients with chronic conditions. METHODS: We used the survey method to collect data from online chronic disease communities and groups on social media platforms. Eligible participants were consumers with at least 1 chronic condition and those who have experience with OHIS. A total of 390 valid questionnaires were collected. The partial least squares approach to structural equation modeling was employed to analyze the data. RESULTS: The results suggested that perceived risk (t=3.989, P<.001) and perceived benefits (t=3.632, P<.001) significantly affected patients' OHIS. Perceived susceptibility (t=7.743, P<.001) and perceived severity (t=8.852, P<.001) were found to influence the perceived risk of chronic diseases significantly. Informational support (t=5.761, P<.001) and emotional support (t=5.748, P<.001) also impacted the perceived benefits of online sources for patients. In addition, moderation analysis showed that critical health literacy significantly moderated the link between perceived risk and OHIS (t=3.097, P=.002) but not the relationship between perceived benefits and OHIS (t=0.288, P=.774). CONCLUSIONS: This study shows that the health belief model, when combined with social support theory, can predict patients' OHIS. The perceived susceptibility and severity can effectively explain perceived risk, further predicting patients' OHIS. Informational support and emotional support can contribute to perceived benefits, thereby positively affecting patients' OHIS. This study also demonstrated the important negative moderating effects of critical health literacy on the association between perceived risk and OHIS.
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Letramento em Saúde , Comportamento de Busca de Informação , Humanos , Apoio Social , Modelo de Crenças de Saúde , Inquéritos e Questionários , Doença Crônica , InternetRESUMO
BACKGROUND: With the world's population aging, more health-conscious older adults are seeking health information to make better-informed health decisions. The rapid growth of the internet has empowered older adults to access web-based health information sources. However, research explicitly exploring older adults' online health information seeking (OHIS) behavior is still underway. OBJECTIVE: This systematic scoping review aims to understand older adults' OHIS and answer four research questions: (1) What types of health information do older adults seek and where do they seek health information on the internet? (2) What are the factors that influence older adults' OHIS? (3) What are the barriers to older adults' OHIS? (4) How can we intervene and support older adults' OHIS? METHODS: A comprehensive literature search was performed in November 2020, involving the following academic databases: Web of Science; Cochrane Library database; PubMed; MEDLINE; CINAHL Plus; APA PsycINFO; Library and Information Science Source; Library, Information Science and Technology Abstracts; Psychology and Behavioral Sciences Collection; Communication & Mass Media Complete; ABI/INFORM; and ACM Digital Library. The initial search identified 8047 publications through database search strategies. After the removal of duplicates, a data set consisting of 5949 publications was obtained for screening. Among these, 75 articles met the inclusion criteria. Qualitative content analysis was performed to identify themes related to the research questions. RESULTS: The results suggest that older adults seek 10 types of health information from 6 types of internet-based information sources and that 2 main categories of influencing factors, individual-related and source-related, impact older adults' OHIS. Moreover, the results reveal that in their OHIS, older adults confront 3 types of barriers, namely individual, social, and those related to information and communication technologies. Some intervention programs based on educational training workshops have been created to intervene and support older adults' OHIS. CONCLUSIONS: Although OHIS has become increasingly common among older adults, the review reveals that older adults' OHIS behavior is not adequately investigated. The findings suggest that more studies are needed to understand older adults' OHIS behaviors and better support their medical and health decisions in OHIS. Based on the results, the review proposes multiple objectives for future studies, including (1) more investigations on the OHIS behavior of older adults above 85 years; (2) conducting more longitudinal, action research, and mixed methods studies; (3) elaboration of the mobile context and cross-platform scenario of older adults' OHIS; (4) facilitating older adults' OHIS by explicating technology affordance; and (5) promoting and measuring the performance of OHIS interventions for older adults.
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Comportamento de Busca de Informação , Intervenção Baseada em Internet , Idoso , Comportamentos Relacionados com a Saúde , Pesquisa sobre Serviços de Saúde , Humanos , Tecnologia da InformaçãoRESUMO
BACKGROUND: The incidence of Takotsubo syndrome (TTS), also known as the broken heart syndrome or stress cardiomyopathy, is increasing worldwide. The understanding of its prognosis has been progressively evolving and currently appears to be poorer than previously thought, which has attracted the attention of researchers. An attempt to recognize the awareness of this condition among the general population drove us to analyze the dissemination of this topic on TikTok, a popular short-video-based social media platform. We found a considerable number of videos on TTS on TikTok; however, the quality of the presented information remains unknown. OBJECTIVE: The aim of this study was to analyze the quality and audience engagement of TTS-related videos on TikTok. METHODS: Videos on the TikTok platform were explored on August 2, 2021 to identify those related to TTS by using 6 Chinese keywords. A total of 2549 videos were found, of which 80 met our inclusion criteria and were evaluated for their characteristics, content, quality, and reliability. The quality and reliability were rated using the DISCERN instrument and the Journal of the American Medical Association (JAMA) criteria by 2 reviewers independently, and a score was assigned. Descriptive statistics were generated, and the Kruskal-Wallis test was used for statistical analysis. Multiple linear regression was performed to evaluate the association between audience engagement and other factors such as video content, video quality, and author types. RESULTS: The scores assigned to the selected video content were low with regard to the diagnosis (0.66/2) and management (0.34/2) of TTS. The evaluated videos were found to have an average score of 36.93 out of 80 on the DISCERN instrument and 1.51 out of 4 per the JAMA criteria. None of the evaluated videos met all the JAMA criteria. The quality of the relayed information varied by source (All P<.05). TTS-related videos made by health care professionals accounted for 28% (22/80) of all the evaluated videos and had the highest DISCERN scores with an average of 40.59 out of 80. Multiple linear regression analysis showed that author types that identified as health professionals (exponentiated regression coefficient 17.48, 95% CI 2.29-133.52; P=.006) and individual science communicators (exponentiated regression coefficient 13.38, 95% CI 1.83-97.88; P=.01) were significant and independent determinants of audience engagement (in terms of the number of likes). Other author types of videos, video content, and DISCERN document scores were not associated with higher likes. CONCLUSIONS: We found that the quality of videos regarding TTS for patient education on TikTok is poor. Patients should be cautious about health-related information on TikTok. The formulation of a measure for video quality review is necessary, especially when the purpose of the published content is to educate and increase awareness on a health-related topic.
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Mídias Sociais , Cardiomiopatia de Takotsubo , Humanos , Disseminação de Informação , Reprodutibilidade dos Testes , Cardiomiopatia de Takotsubo/diagnóstico , Gravação em VídeoRESUMO
Designing a robot with the best accuracy is always an attractive research direction in the robotics community. In order to create a Gough-Stewart platform with guaranteed accuracy performance for a dedicated controller, this paper describes a novel advanced optimal design methodology: control-based design methodology. This advanced optimal design method considers the controller positioning accuracy in the design process for getting the optimal geometric parameters of the robot. In this paper, three types of visual servoing controllers are applied to control the motions of the Gough-Stewart platform: leg-direction-based visual servoing, line-based visual servoing, and image moment visual servoing. Depending on these controllers, the positioning error models considering the camera observation error together with the controller singularities are analyzed. In the next step, the optimization problems are formulated in order to get the optimal geometric parameters of the robot and the placement of the camera for the Gough-Stewart platform for each type of controller. Then, we perform co-simulations on the three optimized Gough-Stewart platforms in order to test the positioning accuracy and the robustness with respect to the manufacturing errors. It turns out that the optimal control-based design methodology helps get both the optimum design parameters of the robot and the performance of the controller {robot + dedicated controller}.
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Past research on women's preferences for male facial masculinity in Western cultures has produced inconsistent results. Some inconsistency may be related to the use of different facial stimulus manipulations (e.g., between-sex sexual dimorphic facial manipulation or within-sex sexual dimorphic facial manipulation) that do not perfectly avoid non-facial cues, and pregnancy status may also influence women's face preferences. We therefore recruited pregnant and nonpregnant Chinese women and manipulated the sexual dimorphism of male facial stimuli to explore the influences of manipulation methods, non-facial cues, and pregnancy status on face preferences. Results showed that: (1) in contrast with a general masculinity preference observed in Western cultures, both pregnant and nonpregnant Chinese women preferred feminized and neutral male faces generally; (2) pregnant women's preference for feminized male faces was stable across manipulation methods, while nonpregnant women preferred feminized male faces except under between-sex sexual dimorphism manipulation; and (3) manipulation methods, rather than non-facial cues, influenced participants' face preferences. Specifically, women showed the strongest preferences for femininity when face stimuli were manipulated by within-sex sexual dimorphic facial manipulation, followed by unmanipulated faces and between-sex sexual dimorphic facial manipulation. This effect was stronger for nonpregnant women in the unmanipulated condition and for pregnant women in the between-sex sexual dimorphic facial manipulation. This research provides empirical evidence of women's preferences for sexual dimorphism in male faces in a non-Western culture, as well as the effects of facial manipulation methods, pregnancy status, and the interactions between these factors.
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Comportamento de Escolha , Feminilidade , Gestantes/psicologia , Caracteres Sexuais , Adulto , Povo Asiático/psicologia , Estudos de Casos e Controles , China , Comportamento do Consumidor , Sinais (Psicologia) , Face , Feminino , Humanos , Masculinidade , Gravidez , Adulto JovemRESUMO
BACKGROUND: Diabetes has become one of the most prevalent chronic diseases, and many people living with diabetes use social media to seek health information. Recently, an emerging social media app, TikTok, has received much interest owing to its popularity among general health consumers. We notice that there are many videos about diabetes on TikTok. However, it remains unclear whether the information in these videos is of satisfactory quality. OBJECTIVE: This study aimed to assess the quality of the information in diabetes-related videos on TikTok. METHODS: We collected a sample of 199 diabetes-related videos in Chinese. The basic information presented in the videos was coded and analyzed. First, we identified the source of each video. Next, 2 independent raters assessed each video in terms of the completeness of six types of content (the definition of the disease, symptoms, risk factors, evaluation, management, and outcomes). Then, the 2 raters independently assessed the quality of information in the videos, using the DISCERN instrument. RESULTS: In regard to the sources of the videos, we found 6 distinct types of uploaders; these included 3 kinds of individual users (ie, health professionals, general users, and science communicators) and 3 types of organizational users (ie, news agencies, nonprofit organizations, and for-profit organizations). Regarding content, our results show that the videos were primarily about diabetes management and contained limited information on the definition of the disease, symptoms, risk factors, evaluation, and outcomes. The overall quality of the videos was acceptable, on average, although the quality of the information varied, depending on the sources. The videos created by nonprofit organizations had the highest information quality, while the videos contributed by for-profit organizations had the lowest information quality. CONCLUSIONS: Although the overall quality of the information in the diabetes videos on TikTok is acceptable, TikTok might not fully meet the health information needs of patients with diabetes, and they should exercise caution when using TikTok as a source of diabetes-related information.
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COVID-19 , Diabetes Mellitus , Mídias Sociais , Diabetes Mellitus/terapia , Humanos , Gravação em VídeoRESUMO
BACKGROUND: Chronic obstructive pulmonary disease (COPD) has become one of the most critical public health problems worldwide. Because many COPD patients are using video-based social media to search for health information, there is an urgent need to assess the information quality of COPD videos on social media. Recently, the short-video app TikTok has demonstrated huge potential in disseminating health information and there are currently many COPD videos available on TikTok; however, the information quality of these videos remains unknown. OBJECTIVE: The aim of this study was to investigate the information quality of COPD videos on TikTok. METHODS: In December 2020, we retrieved and screened 300 videos from TikTok and collected a sample of 199 COPD-related videos in Chinese for data extraction. We extracted the basic video information, coded the content, and identified the video sources. Two independent raters assessed the information quality of each video using the DISCERN instrument. RESULTS: COPD videos on TikTok came mainly from two types of sources: individual users (n=168) and organizational users (n=31). The individual users included health professionals, individual science communicators, and general TikTok users, whereas the organizational users consisted of for-profit organizations, nonprofit organizations, and news agencies. For the 199 videos, the mean scores of the DISCERN items ranged from 3.42 to 4.46, with a total mean score of 3.75. Publication reliability (P=.04) and overall quality (P=.02) showed significant differences across the six types of sources, whereas the quality of treatment choices showed only a marginally significant difference (P=.053) across the different sources. CONCLUSIONS: The overall information quality of COPD videos on TikTok is satisfactory, although the quality varies across different sources and according to specific quality dimensions. Patients should be selective and cautious when watching COPD videos on TikTok.
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COVID-19 , Doença Pulmonar Obstrutiva Crônica , Mídias Sociais , Humanos , Disseminação de Informação , Saúde Pública , Doença Pulmonar Obstrutiva Crônica/terapia , Reprodutibilidade dos Testes , Gravação em VídeoRESUMO
This study investigated consumers' information-avoidance behavior in the context of a public health emergency-the COVID-19 pandemic in China. Guided by the stimulus-organism-response paradigm, it proposes a model for exploring the effects of external stimuli (perceived threat and perceived information overload) related to COVID-19 on consumers' internal states (sadness, anxiety, and cognitive dissonance) and their subsequent behavioral intentions to avoid health information and engage in preventive behaviors. With a survey sample (N = 721), we empirically examined the proposed model and tested the hypotheses. The results indicate that sadness, anxiety, and cognitive dissonance, which were a result of perceived threat and perceived information overload, had heterogeneous effects on information avoidance. Anxiety and cognitive dissonance increased information avoidance intention, while sadness decreased information avoidance intention. Moreover, information avoidance predicted a reluctance on the part of consumers to engage in preventive behaviors during the COVID-19 pandemic. These findings not only contribute to the information behavior literature and extend the concept of information avoidance to a public health emergency context, but also yield practical insights for global pandemic control.
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We report a novel microwave photonic phase and amplitude control structure based on a single microring resonator with a tunable Mach Zehnder interferometer reflective loop, which enables the realization of a continuously tunable microwave photonic phase shifter with enhanced phase tuning range while simultaneously compensating for the RF power variations. The complimentary tuning of the phase and amplitude presents a simplistic approach to resolve the inherent trade-off between maintaining a full RF phase shift while eliminating large RF power variations. Detailed simulations have been carried out to analyze the performance of the new structure as a microwave photonic phase shifter, where the reflective nature of the proposed configuration shows an effective doubling of the phase range while the amplitude compensation module provides a parallel control to potentially reduce the RF amplitude variations to virtually zero. The phase range enhancement, which is first verified experimentally with a passive only chip, demonstrates the capability to achieve a continuously tunable RF phase shift of 0-510° with an RF amplitude variation of 9 dB. Meanwhile, the amplitude compensation scheme is incorporated onto an active chip with a continuously tunable RF phase shift of 0-150°, where the RF power variations is shown to be reduced by 5 dB while maintaining a constant RF phase shift.
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In this Letter, we propose and experimentally demonstrate, to the best of our knowledge, a novel high-performance microwave photonic sensing system employing a reflective double-pass spectrum-slicing sensing scheme, based on low-coherence interferometry in combination with a dispersive medium. The setup is implemented by configuring a double-pass spectrum slicing sensing scheme, which significantly increases the output power level of a low-coherence optical source by approximately 12 dB to compensate for the optical loss of the system. Moreover, since the light passes through the same optical path twice, the conversion efficiency between the applied optical path difference and the dependent radiofrequency (RF) resonance shift is doubled compared to the conventional approaches. It is also possible to realize a very high resolution thanks to the broad bandwidth of the semiconductor optical amplifier (SOA) spectrum. In addition, this SOA-based scheme enables the future realization of a fully integrated sensing system. As an application example, a highly sensitive displacement sensor was investigated, and the experimental results presented a highly linear relationship between the applied OPDs and the RF frequency shifts. The proposed sensing system successfully achieved a high conversion slope of 5.56 GHz/mm and a nearly constant resolution of approximately 124 µm using a Gaussian power density spectrum.