Efficient Discrimination of Hazardous Organophosphate Flame Retardants via Cataluminescence-Based Multidimensional Ratiometric Sensing.

Emerging contaminants have recently evolved into a severe worldwide environmental issue. Organophosphate flame retardants (OPFRs) with neurotoxicity, genotoxicity, and reproductive and developmental toxicity are a class of notorious emerging contaminants that cause great concern. The development of high-efficiency and portable sensors for rapid online monitoring of OPFRs has become the primary demand for the exploration of the environmental migration and transformation of OPFRs. In this work, interestingly, the cataluminescence (CTL) phenomenon of OPFRs is first observed, and an ingenious multidimensional ratiometric CTL sensing strategy is developed for the recognition of multiple OPFRs. Three characteristic ratios are extracted from the multipeak CTL spectral curves based on energy transfer of single Tb/Eu-modified MgO sensing material, and thus a novel three-dimensional (3D) code recognition could be mapped out. This obtained 3D coordinate is found to be a unique characteristic for a given OPFR, just like an exclusive person's ID number, which can successfully discriminate and detect 10 kinds of OPFR vapors, including homologous series and isomers. More importantly, CTL mechanism investigations for OPFRs demonstrate that OPFRs undergo a series of chemical reaction processes, e.g., oxidative pyrolysis and hydroxylation, and different high-energy excited intermediates are generated, which trigger discrepant energy-transfer efficiency toward rare earth ions, leading to multipeak spectral profiles. Briefly, this proposed CTL analytical platform for OPFRs recognition initiates a new sensing principle for the efficient identification of emerging contaminants and shows significant prospects on rapid on-site detection.

Modulating the tumoral SPARC content to enhance albumin-based drug delivery for cancer therapy.

Insufficient delivery of therapeutic agents into solid tumors by systemic administration remains a major challenge in cancer treatment. Secreted protein acidic and rich in cysteine (SPARC) has high binding affinity to albumin and has been shown to enhance the penetration and uptake of albumin-based drug carriers in tumors. Here, we developed a strategy to alter the tumor microenvironment (TME) by upregulating SPARC to enhance the delivery efficiency of albumin-based drug carriers into tumors. We prepared albumin nanoparticles encapsulating an NF-κB controllable CRISPR activation system (SP-NPs). SP-NPs achieved tumor-selective SPARC upregulation by responding to the highly activated NF-κB in tumor cells. Whereas a single dose of SP-NPs only modestly upregulated SPARC expression, serial administration of SP-NPs created a positive feedback loop that induced progressive increases in SPARC expression as well as tumor cell uptake and tumor penetration of the nanoparticles in vitro, in organoids, and in subcutaneous tumors in vivo. Additionally, pre-treatment with SP-NPs significantly enhanced the anti-tumor efficacy of Abraxane, a commercialized albumin-bound paclitaxel nanoformulation. Our data provide evidence that modulating SPARC in the TME can enhance the efficiency of albumin-based drug delivery to solid tumors, which may result in new strategies to increase the efficacy of nanoparticle-based cancer drugs.

Feasibility and potential efficacy of a family-based intervention on promoting physical activity levels and fundamental movement skills in preschoolers: A cluster randomised controlled trial.

Physical activity (PA) is crucial for preschool-aged children's health and development. However, limited evidence exists regarding the feasibility of implementing home-based interventions and how program components influence parent cognitions and practices and child PA. This study evaluated the feasibility and potential efficacy of a family-based PA intervention on objectively measured PA, fundamental movement skills (FMS), parental efficacy, support, goal setting and parent-child co-activity. Guided by social cognitive theory, an 8-week cluster randomised controlled trial was conducted in Hong Kong. The trial included parental workshops, FMS training, PA homework, social media activity sharing and exercise equipment provision. Data were collected at baseline (Time 1; April 2019) and at the end of the intervention period (Time 2; approximately 2 months later) from 108 parent-child pairs in five preschools. The intervention led to increased moderate-to-vigorous PA and FMS in children, along with improved parental self-efficacy, goal setting, supportiveness and co-participation. However, parental PA did not show significant changes. Parents expressed high satisfaction, supporting the need for tailoring interventions to address the unique needs and preferences of young children and their parents. Reinforcing the parental role and providing informative materials and training can promote healthy lifestyles in early childhood.

Achievement Emotions of Medical Students: Do They Predict Self-regulated Learning and Burnout in an Online Learning Environment?

BACKGROUND: Achievement emotions have been proven as important indicators of students' academic performance in traditional classrooms and beyond. In the online learning contexts, previous studies have indicated that achievement emotions would affect students' adoption of self-regulated learning strategies and further predict their learning outcomes. However, the pathway regarding how different positive and negative achievement emotions might affect students' burnout through self-regulated learning among medical students in online learning environments remains unclear. In this study, the aim is to investigate how achievement emotions and self-regulated learning predict burnout among medical students in online education. METHODS: This study involved 282 medical students who had attended online courses due to the sudden shift of learning mode caused by the COVID-19 pandemic in 2022. Confirmatory factor analysis was performed to examine the hypothesized factor structure, and structural equation modelling was conducted to test the hypothesized relationships among factors. RESULTS: The results of structural equation modelling revealed that medical students' self-efficacy positively predicted their enjoyment (ß = .57) and online self-regulated learning (ß = .54). Learning-related boredom inhibited students' adoption of online self-regulated learning strategies (ß = -.24), and it was positively associated with their burnout (ß = .54). Learning-related anxiety was a positive predictor of online self-regulated learning (ß = .38). DISCUSSIONS: The results of this study suggest that achievement emotions experienced by medical students had a significant impact on their online self-regulated learning and burnout. Specifically, the experience of learning-related boredom was detrimental to the adoption of self-regulated learning strategies and increased the likelihood of burnout. However, learning-related anxiety, despite being a negative achievement emotion, was positively associated with students' online self-regulated learning. These findings have important implications for online teaching and learning, particularly in the post-pandemic era.

Engineering redirected NF-κB/OIP5 expression programs to enhance tumor responses to chemotherapy in bladder cancer.

Nuclear factor kappa-B (NF-κB), a pivotal transcriptional regulator, plays a crucial role in modulating downstream genes implicated in tumor drug resistance. We establish a programmable system within bladder cancer cells to tailor drug responses by employing a synthetic clustered regularly interspaced short palindromic repeats (CRISPR)-based expression strategy that emulates natural transcriptional regulators. Our investigation uncovers the functional significance of Opa-interacting protein 5 (OIP5), upregulated upon NF-κB activation, as a key regulator governing drug-resistance to vincristine (VCR) treatment in bladder cancer. Through engineered guide RNAs (sgRNAs) targeting OIP5 to integrate NF-κB aptamers, we construct a modular scaffold RNA that encodes both the target locus and regulatory functionality. This engineered CRISPR scaffold RNA effectively responds to VCR stimulus by binding with activated NF-κB. Intriguingly, it redirects NF-κB to attenuate OIP5 expression-a reversal of its original role-while concurrently obstructing multiple NF-κB-mediated drug resistance pathways. This dual action thwarts drug resistance development. Further enhancing therapeutic potential, we develop a versatile nanoparticle system capable of co-delivering CRISPR scaffold RNAs and VCR. This synergistic approach demonstrates potent anti-tumor effects in both in vitro and in vivo settings. Our nanoparticle-mediated combination presents a compelling proof-of-concept, showcasing the utility of engineered CRISPR-based synthetic expression programs to reconfigure cellular drug responses and heighten tumor cell susceptibility to chemotherapy.

Knowledge Construction in Problem-Based Learning: A Lag-Sequential Analysis of Teachers' and Students' Discourse Moves.

Phenomenon: Problem-based learning (PBL) has been widely adopted in medical schools across the globe. However, the dynamics of discourse moves in time sequences during such learning remain underexplored. This study investigated discourse moves used by PBL tutors and tutees to facilitate collaborative knowledge construction, and adopted sequential analysis to unpack the temporal dynamics of such moves during PBL knowledge construction in an Asian context. Approach: This study's sample comprised 22 first-year medical students and two PBL tutors at an Asian medical school. Two 2-h PBL tutorials were video-recorded and transcribed, and notes were made about the participants' non-verbal behaviors, including but not limited to body language and technology use. Descriptive statistics and visual representations were used to discern participation patterns as they evolved over time, and discourse analysis was applied to identify specific types of teacher and student discourse moves within knowledge construction. Lastly, lag-sequential analysis (LSA) was adopted to understand the sequential patterns of those discourse moves. Findings: The PBL tutors mainly used probing questions, explanation and clarification, compliments, encouragement, affirmation, and requests when facilitating PBL discussions. LSA revealed that discourse moves had the following four major paths. Teachers' content-related questions elicited both lower- and higher-level thinking from students; teachers' statements mediated between students' thinking levels and teachers' questions; there were relationships among teachers' social-facilitation discourse, students' thinking modes, and teachers' statements; and there was a sequential relationship among teachers' statements, students' facilitation, teachers' process-related discourse, and students' silences. Insights: This study revealed the importance of using probing questions to facilitate students' knowledge construction as they proceeded from lower- to higher-level thinking. This study also fills a gap in the current literature by adopting the innovative LSA methodology to explore teachers' and students' discourse move sequences in PBL. The results have important practical implications for PBL tutors regarding when and how to facilitate their students' collaborative knowledge construction.

The spatial linkage mechanism: medical level, public health security, and economic climate from 19 OECD EU countries.

Introduction: The global spread of the COVID-19 has brought about global changes, especially in terms of economic growth. Therefore, it has become a global issue to explore the impact of public health security on the economy. Methods: Employing a dynamic spatial Durbin model, this study analyzes the spatial linkage mechanism of medical level, public health security, and economic climate in 19 countries as well as investigates the relationship between economic climate and COVID-19 by the panel data of 19 OECD European Union countries from March 2020 to September 2022. Results: Results show that an improvement in the medical level can reduce the negative impact of public health security on the economy. Specifically, there is a significant spatial spillover effect. The degree of economic prosperity hurts the reproduction rate of COVID-19. Discussion: Policymakers should consider both the severity of the public health security issues and the economic level when developing prevention and control policies. Given this, corresponding suggestions provide theoretical support for formulating policies to reduce the economic impact of public health security issues.

Strategies to support self-regulated learning in integrated, student-centered curricula.

PURPOSE: With undergraduate medical education shifting to an integrated, student-centered approach, self-regulated learning (SRL) skills are critical for student success. Educational research holds that learning strategy effectiveness is context dependent. Our study aims to explore what strategies medical students use to support SRL when engaged in the specific context of an integrated, student-centered curriculum. APPROACH: This study took place in two medical schools with integrated, student-centered curricula. Semi-structured interviews were conducted with first-year medical students from both schools, asking them to reflect on the learning strategies they used throughout their first year of medical school. Interview data was analyzed first deductively using the SRL framework and then inductively to understand the specific strategies being used. FINDINGS: Students engaged in strategies to support SRL in ways that were unique to the integrated, student-centered context. We found that medical students developed strategies to plan for integration and building connections across material during all three phases of self-regulated learning. INSIGHTS: By identifying specific tasks and behaviors students utilized during their first year of medical school, this study provides a roadmap that students and educators can use to help students become self-regulated learners.

Towards a global partnership model in interprofessional education for cross-sector problem-solving.

OBJECTIVES: A partnership model in interprofessional education (IPE) is important in promoting a sense of global citizenship while preparing students for cross-sector problem-solving. However, the literature remains scant in providing useful guidance for the development of an IPE programme co-implemented by external partners. In this pioneering study, we describe the processes of forging global partnerships in co-implementing IPE and evaluate the programme in light of the preliminary data available. METHODS: This study is generally quantitative. We collected data from a total of 747 health and social care students from four higher education institutions. We utilized a descriptive narrative format and a quantitative design to present our experiences of running IPE with external partners and performed independent t-tests and analysis of variance to examine pretest and posttest mean differences in students' data. RESULTS: We identified factors in establishing a cross-institutional IPE programme. These factors include complementarity of expertise, mutual benefits, internet connectivity, interactivity of design, and time difference. We found significant pretest-posttest differences in students' readiness for interprofessional learning (teamwork and collaboration, positive professional identity, roles, and responsibilities). We also found a significant decrease in students' social interaction anxiety after the IPE simulation. CONCLUSIONS: The narrative of our experiences described in this manuscript could be considered by higher education institutions seeking to forge meaningful external partnerships in their effort to establish interprofessional global health education.

Students' interaction anxiety and social phobia in interprofessional education in Hong Kong: mapping a new research direction.

BACKGROUND: Interprofessional education (IPE) has been promoted as a breakthrough in healthcare because of the impact when professionals work as a team. However, despite its inception dating back to the 1960s, its science has taken a long time to advance. There is a need to theorize IPE to cultivate creative insights for a nuanced understanding of IPE. This study aims to propose a research agenda on social interaction by understanding the measurement scales used and guiding researchers to contribute to the discussion of social processes in IPE. METHOD: This quantitative research was undertaken in a cross-institutional IPE involving 925 healthcare students (Medicine, Nursing, Social Work, Chinese Medicine, Pharmacy, Speech Language Pathology, Clinical Psychology, Food and Nutritional Science and Physiotherapy) from two institutions in Hong Kong. Participants completed the Social Interaction Anxiety Scale (SIAS-6) and Social Phobia Scale (SPS-6). We applied a construct validation approach: within-network and between-network validation. We performed confirmatory factors analysis, t-test, analysis of variance and regression analysis. RESULTS: CFA results indicated that current data fit the a priori model providing support to within-network validity [RMSEA=.08, NFI=.959, CFI=.965, IFI=.965, TLI=.955]. The criteria for acceptable fit were met. The scales were invariant between genders, across year levels and disciplines. Results indicated that social interaction anxiety and social phobia negatively predicted behavioural engagement (F = 25.093, p<.001, R2=.065) and positively predicted behavioural disaffection (F = 22.169, p<.001, R2=.057) to IPE, suggesting between-network validity. CONCLUSIONS: Our data provided support for the validity of the scales when used among healthcare students in Hong Kong. SIAS-6 and SPS-6 have sound psychometric properties based on students' data in Hong Kong. We identified quantitative, qualitative and mixed methods research designs to guide researchers in getting involved in the discussion of students' social interactions in IPE.Key MessagesThe Social Anxiety Scale (SIAS-6) and Social Phobia Scale (SPS-6) scales have sound psychometric properties based on the large-scale healthcare students' data in IPE in Hong Kong.Social interaction anxiety and social phobia negatively predicted students' behavioural engagement with IPE and positively predicted behavioural disaffection. The scales are invariant in terms of gender, year level and discipline.Quantitative, qualitative and mixed methods studies are proposed to aid researchers to contribute in healthcare education literature using the SIAS-6 and SPS-6.

From self-regulation to co-regulation: refining learning presence in a community of inquiry in interprofessional education.

INTRODUCTION: Online interprofessional education is a collaborative process that emphasizes both individual reflection and shared discourses. A useful analytical tool for understanding the complex dynamics of online collaborative learning is the community of inquiry (CoI) framework, which originally held that there are three types of presence in such learning: teaching, cognitive, and social. However, it was later revised to include learning presence, which is characterized by self-regulated learning. Our study aims to refine the construct of learning presence through a clearer understanding of how self- and co-regulation jointly influence learning outcomes. METHODS: We surveyed 110 people involved with an online interprofessional medical-education curriculum at a university in Hong Kong. Path analysis was adopted to explore the relationships among 1) the three original presences of CoI; 2) learning presence (i.e., for this purpose, a combination of self-regulation and co-regulation); and 3) two learning outcomes: perceived progress and learner satisfaction. RESULTS: The results of path analysis indicated that teaching presence had a significant indirect effect, through co-regulation, on perceived progress. In terms of direct relationships, co-regulation significantly and positively influenced both self-regulation and cognitive presence; and social presence had both positive influence on learners' satisfaction and perceived progress. DISCUSSION: This study's findings suggest the important role of co-regulation in supporting self-regulation, especially in online collaborative-learning environments. Learners' self-regulation skills are shaped by their social interactions and regulatory activities with others. This further implies that health-professions educators and instructional designers should create learning activities that facilitate the development of co-regulatory skills, as a means of improving learning outcomes. As self-regulation is an important skill for health professions learners' lifelong learning, and because their future workplaces will be interdisciplinary in nature, it is critical to provide interactive and collaborative learning environments that will promote co-regulation and self-regulation.

Efficient photocatalytic degradation of ciprofloxacin by graphite felt-supported MnS/Polypyrrole composite: Dominant reactive species and reaction mechanisms.

The accumulation of antibiotics in aquatic environments poses a serious threat to human health. Photocatalytic degradation is a promising method for removing antibiotics from water, but its practical implementation requires improvements in photocatalyst activity and recovery. Here, a novel graphite felt-supported MnS/Polypyrrole composite (MnS/PPy/GF) was constructed to achieve effective adsorption of antibiotics, stable loading of photocatalyst, and rapid separation of spatial charge. Systematic characterization of composition, structure and photoelectric properties indicated the efficient light absorption, charge separation and migration of the MnS/PPy/GF, which achieved 86.2% removal of antibiotic ciprofloxacin (CFX), higher than that of MnS/GF (73.7%) and PPy/GF (34.8%). The charge transfer-generated 1O2, energy transfer-generated 1O2, and photogenerated h+ were identified as the dominant reactive species, which mainly attacked the piperazine ring in the photodegradation of CFX by MnS/PPy/GF. The •OH was confirmed to participate in the defluorination of CFX via hydroxylation substitution. The MnS/PPy/GF-based photocatalytic process could ultimately achieve the mineralization of CFX. The facile recyclability, robust stability, and excellent adaptability to actual aquatic environments further confirmed MnS/PPy/GF is a promising eco-friendly photocatalyst for antibiotic pollution control.

Effect of soluble salts in electrolytic manganese residue on its geotechnical characteristics.

Electrolytic Manganese Residue (EMR) is a solid waste containing soluble sulfate, discharged by electrolytic manganese industries. The accumulation of EMR in ponds poses a significant hazard to both safety and the environment. This study utilized innovative geotechnical test techniques to conduct a series of tests, investigating the effect of soluble salts on the geotechnical characteristics of EMR. The results revealed that soluble sulfates had a significant impact on the geotechnical characteristics of the EMR. In particular, the infiltration of water leached away the soluble salts, causing a non-uniform particle size distribution and decreasing the shear strength, stiffness, and liquefaction resistance of the EMR. Nevertheless, an increase in the stacking density of EMR could improve its mechanical characteristics and inhibited the dissolution of soluble salts. Therefore, increasing the density of stacked EMR, ensuring the effectiveness and non-obstruction of the water interception facilities, and reducing rainwater infiltration could be effective measures to enhance the safety and reduce the environmental hazard of EMR ponds.

Experimental study on dynamic behavior of polyacrylamide-reinforced tailings.

Earthquakes are a significant factor that contributes to tailings dam failure. Generally, the seismic stability of a tailings dam can be increased by improving the dynamic properties of tailings. The dynamic properties of tailings can be improved effectively using polymers. In this study, the dynamic properties of polyacrylamide-reinforced tailings were investigated via a sequence of dynamic triaxial tests. The content of polyacrylamide in the test sample was 0.3%. Test results show that the cyclic liquefaction resistance, initial dynamic shear modulus, dynamic shear modulus, and dynamic shear modulus ratio of polyacrylamide-reinforced tailings were slightly greater than those of unreinforced tailings. The damping ratio of polyacrylamide-reinforced tailings was lower than that of unreinforced tailings when the dynamic shear strain exceeded 0.038%. The increase in the dynamic pore water pressure of polyacrylamide-reinforced tailings during cyclic loading decelerated significantly compared with that of unreinforced tailings. The revised Zeng model can effectively described the changes in dynamic pore-water pressure of unreinforced and polyacrylamide-reinforced tailings. The polyacrylamide can improve the structural stability of the tailings specimen and also improve the dynamic properties of the tailings, thereby enhancing the seismic stability of the tailings dam.

A Soil Moisture Prediction Model, Based on Depth and Water Balance Equation: A Case Study of the Xilingol League Grassland.

Soil moisture plays an important role in ecology, hydrology, agriculture and climate change. This study proposes a soil moisture prediction model, based on the depth and water balance equation, which integrates the water balance equation with the seasonal ARIMA model, and introduces the depth parameter to consider the soil moisture at different depths. The experimental results showed that the model proposed in this study was able to provide a higher prediction accuracy for the soil moisture at 40 cm, 100 cm and 200 cm depths, compared to the seasonal ARIMA model. Different models were used for different depths. In this study, the seasonal ARIMA model was used at 10 cm, and the proposed model was used at 40 cm, 100 cm and 200 cm, from which more accurate prediction values could be obtained. The fluctuation of the predicted data has a certain seasonal trend, but the regularity decreases with the increasing depth until the soil moisture is almost independent of the external influence at a 200 cm depth. The accurate prediction of the soil moisture can contribute to the scientific management of the grasslands, thus promoting ecological stability and the sustainable development of the grasslands while rationalizing land use.

Silencing of Long Noncoding RNA TUG1 Ameliorates Atherosclerosis-Induced Myocardial Injury by Upregulating microRNA-30b-3p and Downregulating Brd4.

ABSTRACT: Long noncoding RNAs and microRNAs (miRNAs) are emerging biomarkers involved in human diseases, and we focused on the roles of long noncoding RNA taurine upregulated gene 1 (TUG1) and miR-30b-3p in the related mechanisms of atherosclerosis-induced myocardial injury. ApoE-deficient mice were fed with high-fat diet to establish atherosclerotic models and then were subjected to either TUG1 downregulation or miR-30b-3p upregulation treatment. The serum myocardial enzymes, inflammatory biomarkers, pathological changes, intramyocardial macrophage infiltration, and apoptosis of cardiomyocytes in atherosclerotic mice were determined. The expression of TUG1, miR-30b-3p, and bromodomain protein 4 (Brd4) in atherosclerotic models was evaluated. Moreover, the correlations of TUG1, miR-30b-3p, and Brd4 were verified. TUG1 and Brd4 were increased while miR-30b-3p was decreased in atherosclerotic mice. The silenced TUG1 or elevated miR-30b-3p attenuated atherosclerosis-induced myocardial injury mainly by reducing serum myocardial enzyme content and inflammatory response, improving pathological changes, and preventing macrophage infiltration and cardiomyocyte apoptosis in atherosclerotic mice. Mechanistically, TUG1 could competitively bind with miR-30b-3p to prevent the degradation of its target gene Brd4. This study reveals that the silencing of TUG1 ameliorates atherosclerosis-induced myocardial injury by upregulating miR-30b-3p and downregulating Brd4, which may provide novel targets for atherosclerosis treatment.

Near-peer teaching in problem-based learning: Perspectives from tutors and tutees.

INTRODUCTION: This study explores how tutors and tutees perceived their teaching and learning experience in a near-peer teaching programme within a formal undergraduate medical-education curriculum. METHODS: This mixed-methods study was conducted in an Asian medical school. First, a survey was administered to two groups of students, one that had been tutored by near-peers, and another with faculty tutors. Then, the near-peer tutors were interviewed and wrote reflection essays that the researchers collected. Quantitative analysis was used to analyse the survey responses, and qualitative analysis to analyse the interview and reflection data. RESULTS: Our study found no difference between near-peer tutees' and faculty tutees' perceptions of either tutor facilitation or tutor behaviours. Also, when near-peer tutors explained how their experience of delivering tutoring had influenced their professional-identity formation, they highlighted that they had gained skills important to their future careers as medical educators. CONCLUSION: Integrating near-peer teaching into undergraduate medical curricula could be beneficial to both tutors and tutees because of the social, cognitive, and professional congruence between these two groups, and due to its likely positive influence on their professional-identity formation.

Research on commodity business value and customer value of e-commerce platforms: Based on consumer psychology and cognition.

Under the background of economic globalization and COVID-19, online shopping has gradually replaced offline shopping as the main shopping mode. In this paper, consumers' perceptions are introduced into the traditional BCG matrix to form a new BCG matrix, and according to it, the small gifts of a gift e-commerce platform are classified. We then performed a robustness test comparing the BCG matrix with K-means clustering. We found that new BCG matrix can objectively reflect the value of small gifts and provide suggestions for the e-commerce platform to make subsequent product decisions. Then we judge the customer value of the platform based on the improved RFM model and K-means++ clustering, and provide a reasonable customer value classification method for the e-commerce platform. Finally, we comprehensively consider the relationship between the commodity value and customer value, and analyze the preferences of different types of customer groups for different types of small gifts. Our research result shows that small gifts can be divided into 4 categories according to commodity value, namely "stars," "cash cows," "questions marks," and "dogs." These four categories of small gifts can be converted into each other through marketing ploys. Customers can be divided into important retention customers, key loyal customers and general development customers according to their values. Faced with different types of customers, managers can adopt different strategies to extract customer value. However, consumer psychology will affect consumer cognition, and different types of consumers prefer different types of small gifts, so the precise implementation of marketing strategies will effectively improve the profitability of the gift e-commerce platform. Compared with the traditional classification method, the commodity business value classification method proposed in this paper uses management analysis and planning methods, and introduces consumer psychological factors into the commodity and customer classification, so that the classification results are more credible. In addition, we jointly analyze the results of commodity value classification and customer value classification, and analyze in detail the preferences of different valued customer groups for different types of commodities, so as to provide directions for subsequent research on customer preference.

A Twitter-facilitated professional learning community: online participation, connectedness, and satisfaction.

BACKGROUND: Twitter has gained increasing popularity and attention as a professional learning environment to share knowledge, exchange information, make connections, and build networks. To evaluate the effectiveness of Twitter-facilitated online discussions, a community of inquiry framework could be used with the three key elements of online environments: cognitive presence, social presence, and teaching presence. This study aims to explore how medical educators participate in synchronous online discussions on Twitter using #MedEdChat, and how participants' perceptions toward the three presences, sense of connectedness and interactions influenced their online satisfaction. METHODS: A survey invitation was emailed using the medical education email list DR-ED and was posted during the weekly Twitter conversations in December 2020, to solicit participants who have been involved in any kind of #MedEdChat activities (i.e., read transcripts or directly participate in discussions). RESULTS: A total of 68 people responded. Through descriptive analysis and path analysis, we found that almost half of the survey respondents were lurkers on #MedEdChat who read others' tweets or transcripts. In addition, participants mainly used Twitter for resource sharing, collaborating with others, and networking. Participants rated teaching (i.e., moderator) presence the highest, followed by overall satisfaction, cognitive presence, sense of connectedness, social presence, and interactions. Among them, sense of connectedness and cognitive presence were significantly associated with participants' overall satisfaction. CONCLUSIONS: This study provided significant implications for using Twitter as a professional learning community to conduct online discussion activities. Facilitators could think of ways to improve participation by providing tutorials on how to participate on Twitter discussions, introduce or ask new participants to introduce themselves, facilitate discussion with intriguing questions, and invite medical educators of different roles as well as medical students and residents to join to bring in diverse perspectives.

Elastic mechanics solution of thermal expansion of bi-material curved beam and its application to negative thermal expansion metamaterials.

Thermal stress impacts various engineering fields significantly, such as aerospace and precision instruments. This adverse effect can be greatly reduced, if not eliminated, by the application of micro-thermal expansion materials, and bi-material beams are widely utilized in the design of micro-thermal expansion structures, thereby exhibiting great application potentials. The elasticity solution of bi-material curved beam under free thermal expansion has been proposed by scholars. Based on this solution, the simplified form is proposed in this paper, and extended to the case where the rotation angles at both ends of the circular arc are constrained under thermal loads. Besides, the geometric parameters and the nonlinear problems of the thermal expansion of bi-material curved beam are analyzed. In addition, a novel type of negative thermal expansion material has been designed by applying the bi-material curved beam to the tetra chiral and anti-tetra chiral materials. The proposed material has greater negative thermal expansion effect than the traditional tetra and anti-tetra chiral materials that are with straight beams.