Study on Nutritional Knowledge, Attitude and Behavior of Chinese School Football Players.

OBJECTIVE: This study aims to validate previous structural models of factors influencing dietary behavior changes and construct the knowledge, attitude, and behavioral models of youth school football players. METHODS: 279 school football players aged 12-17 years in Grades 7-12 in Hunan Province, China, completed a questionnaire to collect data on sports nutrition knowledge, attitudes, and behavior. A structural equation model (SEM) was built based on the knowledge-attitude-behavior (KAB) model and the theory of planned behavior (TPB) model to introduce nutritional knowledge directly or by altering attitudes into the dietary behavior path of players. Four factors affecting dietary behaviors were involved in the hypothetical structure, which consists of the following hypotheses: (1) nutrition knowledge affects the attitude towards sports nutrition (H1); (2) nutrition knowledge affects dietary behaviors (H2); (3) nutrition knowledge affects subjective norms (H3); (4) nutrition knowledge affects perceived behavioral control (H4); (5) subjective norms affect dietary behaviors (H5); and 6) perceived behavioral control affects dietary behaviors (H6). RESULTS: Confirmatory factor analysis (CFA) revealed that the reliability, convergent validity, and discriminant validity of the built SEM conformed to the measured relationships in each dimension. In the final structural model, it was found that nutrition knowledge had a direct impact on the attitudes of players and affected their dietary behaviors in a direct manner or through their subjective norms and perceived behavioral control. CONCLUSIONS: The results are in agreement with the TPB-based KAB chain and support the KAB theory for youth school football players in Hunan Province, China.

Changes in Physical Health-Related Indexes of Chinese College Students before and after COVID-19 Lockdown.

The outbreak of the COVID-19 pandemic has caused negative impacts on people's lifestyles, as well as considerable indirect social impacts, which has even overshadowed the direct impact of virus infection itself. This study is aimed at examining the changes in physical health-related indexes of Chinese college students before and after the COVID-19 lockdown. The data of this study are from the National Physical Health Testing Program, covering 43 college students (male: 22) from a class of a Chinese university. Paired t-tests were performed on the physical health test data separately collected in November 2019 before the COVID-19 pandemic and October 2020 after the COVID-19 lockdown was lifted. As shown by the test results, compared to the prelockdown data, college students had an increased body mass index (BMI) (0.43 (SD 0.94) P = 0.004), decreased vital capacity (VC) (-128.98 (SD 310.13) ml P = 0.009), and lowered performance in the 800/1000 m endurance (-6.21 (SD 8.81) points P < 0.001) and standing long jump tests (-2.44 (SD 7.37) points P = 0.036) after the lockdown, and the differences in these regards all were significant. In addition, for the students in the overweight/obese group, their pre- and postlockdown physical fitness test results were found to have no statistically significant difference (P > 0.05), but the students in the control group showed a significantly increased BMI, as well as significantly decreased vital capacity and performance in the 800/1000 m endurance and standing long jump tests (P < 0.05). The findings of this study are expected to help government departments and policymakers better understand the impacts of school closures and online learning on the physical health of adolescents, while providing a basis for the formulation of measures that are aimed at reversing adolescents' physical health decline.

The effects of the measures against COVID-19 pandemic on physical activity among school-aged children and adolescents (6-17 years) in 2020: A protocol for systematic review.

BACKGROUND: The pandemic of coronavirus disease (COVID-19) has greatly changed people's daily lives, forcing countries to take actions, such as school shutdown, lockdown, isolation, and social distancing measures. It remains unclear how the closures, cancellations, and restrictions of schools and courses as a response to the COVID-19 pandemic affect the engagement of school-aged children and adolescents in relation to physical activity (PA). METHODS: The articles in the databases of EBSCO (including AMED, CINAHL Plus, Health Business, Health Source MEDLINE with Full Text, APA PsycArticles, APA PsycINFO, and SPORTDiscus) published during the period from 1 January 2020 to 31 December 2020 will be retrieved, and the data in the selected articles are extracted, including research methods, demographics, and key results. Search outcomes were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Mixed Methods Appraisal Tool (MMAT) will be used to evaluate research quality. Two reviewers are responsible for completing the three tasks, namely selecting the articles that meet the inclusion criteria, extracting data in the articles selected, and evaluating their research quality. All findings, and especially primary outcomes will be summarized in a table format of findings. The results will provide a high-quality synthesis of current evidence for researchers in this subject area. AIM: The objective of this systematic review is to investigate the effects of the COVID-19 pandemic on PA in children and adolescents aged 6-17 years during 2020. 1). What impact has the COVID-19 pandemic had on PA levels in school-aged children and adolescents? 2). Investigating changes in the locations of school-aged children's and adolescents' PA between the pre-COVID-19 period (January 2020) and the COVID-19 period (December 2020). RESULTS: We hope that this study will provide government authorities and health professionals with the necessary information in guiding actions and allocating resources, so that the situation of physical inactivity in school-aged children and adolescents during the COVID-19 pandemic can be improved, thereby enhancing their physical health. PROTOCOL REGISTRATION NUMBER: This review was submitted and registered under CRD42020225976 in PROSPERO.

Factors That Influence Participation in Physical Activity in School-Aged Children and Adolescents: A Systematic Review from the Social Ecological Model Perspective.

High prevalence of physical inactivity and obesity in children and adolescents has become a global problem. This systematic review aimed to examine the existing literature regarding the factors that influence participation in physical activity (PA) in children and adolescents with reference to the social ecological model (SEM) proposed by McLeroy et al. (1988). The SEM provides a framework under which the influencing factors are categorized into five levels: intrapersonal, interpersonal, organizational, community, and public policy. A systematic search of relevant literature published before July 2020 was conducted through Ebsco, ProQuest, PubMed Central, Scopus, and Web of Science. A total of fourteen studies met the inclusion criteria. The selected articles were all of high quality as assessed using the Mixed Methods Appraisal Tool (2018). The results indicated that gender, age, ethnicity, and self-concept were the most common influencing factors at the intrapersonal level. At the interpersonal and organization levels, supports from friends, parents, and teachers were positive predictors of students' PA participation. Accessibility of facilities and safe neighborhoods was a crucial factor that influenced children and adolescents' participation in PA at the community level. Future studies on the effective types of policies or practices that could successfully promote facilities' accessibility and improve neighborhood safety are required. The outcomes of this systematic review are expected to inform practice and support the development and implementation of sound policies for the promotion of PA participation in children or adolescents from a comprehensive social ecological viewpoint.

Metal-Organic Framework-Surface-Enhanced Infrared Absorption Platform Enables Simultaneous On-Chip Sensing of Greenhouse Gases.

Simultaneous on-chip sensing of multiple greenhouse gases in a complex gas environment is highly desirable in industry, agriculture, and meteorology, but remains challenging due to their ultralow concentrations and mutual interference. Porous microstructure and extremely high surface areas in metal-organic frameworks (MOFs) provide both excellent adsorption selectivity and high gases affinity for multigas sensing. Herein, it is described that integrating MOFs into a multiresonant surface-enhanced infrared absorption (SEIRA) platform can overcome the shortcomings of poor selectivity in multigas sensing and enable simultaneous on-chip sensing of greenhouse gases with ultralow concentrations. The strategy leverages the near-field intensity enhancement (over 1500-fold) of multiresonant SEIRA technique and the outstanding gas selectivity and affinity of MOFs. It is experimentally demonstrated that the MOF-SEIRA platform achieves simultaneous on-chip sensing of CO2 and CH4 with fast response time (<60 s), high accuracy (CO2: 1.1%, CH4: 0.4%), small footprint (100 × 100 µm2), and excellent linearity in wide concentration range (0-2.5 × 104 ppm). Additionally, the excellent scalability to detect more gases is explored. This work opens up exciting possibilities for the implementation of all-in-one, real-time, and on-chip multigas detection as well as provides a valuable toolkit for greenhouse gas sensing applications.

Integrating a Microwave Resonator and a Microchannel with an Immunochromatographic Strip for Stable and Quantitative Biodetection.

An immunochromatographic strip is an effective diagnostic tool in various fields because of its simplicity, rapidity, and cost-effectiveness. However, typical strips for preliminary screening provide only qualitative or semiquantitative results, and common solutions for quantitative detection by incorporating different kinds of nanoparticles as biomarkers still do not solve this problem thoroughly. Here, we try to tackle this challenge by integrating low-cost membrane-compatible square split-ring resonators and structure-design-flexible microchannels with flexible strips. We experimentally demonstrate that the limit of detection (LOD) and sensitivity of the strip for quantitative detection of Staphylococcus aureus reach 0.784 ng/mL and 10.214 MHz/(ng/mL), respectively. The LOD level is about 63 times higher than that of the color-based strip determined by the naked eye, and the stability is about 18 times higher than that of the fluorescent strip. This work could not only provide a powerful diagnosis tool for the quantitative detection of S. aureus or other molecules but also deliver new avenues for achieving electric field detection of biomolecules, system-level integration of biosensors, and the development of portable diagnostic devices.

Multi-Band Sensing for Dielectric Property of Chemicals Using Metamaterial Integrated Microfluidic Sensor.

The growth of the chemical industry has brought tremendous challenges to chemical sensing technology. Chemical sensors based on metamaterials have great potential because of their label-free and non-destructive characteristics. However, metamaterials applied in chemical sensing have mainly been investigated from the measurement of sample concentration or the determination of the dielectric properties at a fixed frequency. Here we present a metamaterial integrated microfluidic (MIM) sensor for the multi-band sensing for dielectric property of chemicals, which is promising for the identification of chemicals. The MIM sensor mainly consists of multiple pair of high sensitive symmetrical double split-ring resonators (DSRRs) and meandering microfluidic channels with a capacity of only 4 µL. A dielectric model has been innovatively established and experimentally verified to accurately estimate the complex permittivity and thus realize the multi-band sensing of dielectric property of chemicals. With the increase in the number of resonators in the sensor, a dielectric spectrum like curve could be obtained for more detailed dielectric information. This work delivers a miniaturized, reusable, label-free and non-destructive metamaterial-microfluidic solution and paves a way of the multi-band sensing for dielectric property of chemicals.

A double-helix-structured triboelectric nanogenerator enhanced with positive charge traps for self-powered temperature sensing and smart-home control systems.

Triboelectric nanogenerators (TENGs) have been in spotlight for their excellent capability to drive miniature electronics. Herein, we report a sophisticated double-helix-structured triboelectric nanogenerator (DHS-TENG) enhanced with positive charge traps for self-powered temperature sensing and smart-home control system. The DHS-TENG increases the charge density on the contact surfaces by taking advantage of the ferroelectric characteristics of polyvinylidene fluoride (PVDF). In addition, the flexible double-helix-structure endows DHS-TENG with excellent elastic property as it has no external supporting materials. The reported DHS-TENG, with the dimensions of 3 cm × 3 cm × 5 cm and a light weight of 10 g, can deliver a peak output power of 9.03 mW under a loading resistance of 4 MΩ. It also delivers an enhanced output performance of 460 V, 140 µA and 400 nC under a constant contact force of 40 N. Furthermore, the DHS-TENG is capable of powering 120 green LEDs and enabling a temperature sensor to work properly. In particular, the DHS-TENG demonstrates the capability of successful remote data transmission for application in smart-home control systems within 10 meters.