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One challenge to the success of online knowledge-sharing communities relates to the participants' longtime participation. Literature has explored the determinants of initial participation rather than longtime participation despite...
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One challenge to the success of online knowledge-sharing communities relates to the participants' longtime participation. Literature has explored the determinants of initial participation rather than longtime participation despite significant differences between them. To fill this research gap, this article conceptualizes involvement and continuous commitment regarding longtime participation and examines their antecedents in the Chinese context. Extending the expectancy-value theory, knowledge-sharing expectancy, knowledge-sharing value, and knowledge-sharing affect are identified as antecedents of involvement and continuous commitment. This article further suggests that interpersonal trust and the norm of reciprocity are important contextual factors in the Chinese context that enhance the positive impacts of these antecedents on involvement and continuous commitment. Empirical results confirm most hypotheses. Interestingly, the impact of knowledge-sharing affect is not influenced by interpersonal trust or the norm of reciprocity. Both theoretical and practical implications are discussed.
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Purpose The purpose of this paper is to examine the impacts of perceived informational value and perceived relational value on feedback-seeking intention in online communities of inquiry (OCoIs). To develop an integrated theoretic...
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Purpose The purpose of this paper is to examine the impacts of perceived informational value and perceived relational value on feedback-seeking intention in online communities of inquiry (OCoIs). To develop an integrated theoretical framework, the antecedents of perceived informational value and perceived relational value are also investigated. Design/methodology/approach This study builds on the relational communication theory (RCT) and the social psychology perspective to develop an integrated research model regarding feedback-seeking. Hypotheses were empirically tested using data collected from 262 subjects who are members of OCoIs. Findings The results indicate that feedback-seeking intention is positively affected by perceived informational and relational value of feedback-seeking. Furthermore, perceived informational value partially mediates the effects of feedback-seeking self-efficacy and learning goal orientation on feedback-seeking intention; perceived relational value partially mediates the effects of social influence and social risk on feedback-seeking intention. Practical implications - The results suggest that practitioners can promote feedback-seeking by enhancing learners' informational and relational dependencies on OCoIs. To achieve effective online learning, practitioners should consider learners' characteristics to provide personalized learning interventions. Originality/value This study advances RCT and the social psychology perspective to develop an integrated model for understanding feedback-seeking. The empirical results complement information-related explanations of feedback-seeking by finding that a relationship-related explanation is more important for promoting feedback-seeking in OCoIs. The proposed model also indicates that tolerance for ambiguity serves as a moderator in the relationship between perceived informational value and its antecedents.
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Purpose The study aims to develop a comprehensive theoretical model to understand the relationship between feedback and individual creativity in a social learning context. To achieve the goal, the study unravels the mechanism unde...
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Purpose The study aims to develop a comprehensive theoretical model to understand the relationship between feedback and individual creativity in a social learning context. To achieve the goal, the study unravels the mechanism underlying the relationship between evaluative feedback and creativity development and examines the interaction effects between informative feedback and evaluative feedback. Design/methodology/approach The study draws on the stimulus-organism-response (S-O-R) framework to develop the research model. A laboratory experiment with a self-designed social learning platform was conducted to test the model. A total of 125 subjects participate in the experiment. Findings The empirical findings reveal that evaluative feedback affects creativity via intrinsic motivation and perceived feedback accuracy and informative feedback moderates the effects of negative feedback on intrinsic motivation and perceived feedback accuracy. Practical implications Organizations should be conscious of the role feedback plays in individual creativity development when building a social learning platform. Specifically, organizations can guide learners to provide favorable online feedback as well as train learners to cope with feedback effectively in creative tasks. Originality/value The study integrates feedback and creativity literature to propose three important mediators and examines the roles of the mediators in the process of creativity development in a social learning context, extending current understanding on the direct relationship between feedback and creativity. The study also complements the existing feedback literature by investigating the interactions between different types of peer feedback in the model of creativity development.
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(1) Background Misinformation is prevalent on social media in the age of COVID-19, exacerbating the threat of the pandemic. Uncovering the processes underlying people’s misinformation sharing using social media assists people to ...
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(1) Background Misinformation is prevalent on social media in the age of COVID-19, exacerbating the threat of the pandemic. Uncovering the processes underlying people’s misinformation sharing using social media assists people to cope with misinformation during the COVID-19 pandemic. This study extends the stimulus-organism-response framework to examine how individuals’ social media dependency relates to their misinformation sharing behavior, with a focus on the underlying processes. (2) Methods A total of 393 valid questionnaires were collected using a survey method to test the proposed research model. (3) Results The results demonstrate that informational dependency and social dependency engender both positive and negative cognitive states, namely perceived information timeliness, perceived socialization and social overload, which then invoke positive as well as negative affect. What is more, the results show that both positive affect and negative affect can engender misinformation sharing. (4) Conclusions Theoretically, this study uncovers the processes that lead to misinformation sharing on social media during the COVID-19 pandemic. Practically, this study provides actionable guidelines on how to manage social media usage and social media content to cope with misinformation sharing during the pandemic.
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Foods of animal origin, as nutritional supplements, are usually consumed after cooking, but residues of amphenicols in fresh raw meat threaten human health. Therefore, this study was designed to evaluate the effects of boiling, de...
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Foods of animal origin, as nutritional supplements, are usually consumed after cooking, but residues of amphenicols in fresh raw meat threaten human health. Therefore, this study was designed to evaluate the effects of boiling, deep-frying and microwave processing under different time conditions on the residue levels of amphenicols and metabolites in livestock and poultry meat. Antibiotic-free pork, beef, lamb and chicken samples were spiked with chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF) and florfenicol amine (FFA) standard solutions and made into homogeneous meat blocks. These positive mock meat blocks were processed using three different cooking methods, and the analyses were performed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results showed that cooking methods, time and food matrices were the main factors influencing the changes in amphenicols and metabolites residues in livestock and poultry meat. With the increase in cooking time, boiling processing was the most effective in reducing the four drug residues in livestock and poultry meat matrices, followed by deep-frying, while microwaving caused an increase in drug residue concentrations. Although boiling and frying processes are effective strategies to reduce amphenicols and metabolites residues in meat, it cannot be assumed that these residues can always decrease to levels that are safe for consumer health, especially when the drug residue concentrations in raw meat are above the maximum residue limits (MRLs). Therefore, it is not reliable to remove residues of amphenicols and metabolites from food by cooking. The solution to the food safety problem of veterinary drug residues must start from the breeding source and accelerate the implementation of antibiotic reduction, antibiotic substitution and antibiotic-free farming.
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DNA-based vaccine is a promising candidate for immunization and induction of a T-cell-focused protective immune response against infectious pathogens such as Mycobacterium tuberculosis (M. tb). To induce multi-functional T respons...
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DNA-based vaccine is a promising candidate for immunization and induction of a T-cell-focused protective immune response against infectious pathogens such as Mycobacterium tuberculosis (M. tb). To induce multi-functional T response against multi-TB antigens, a multi-epitope DNA vaccine and a protein backbone grafting' design method is adopted to graft five discontinuous T-cell epitopes into HSP65 scaffold protein of M. tb for enhancement of epitope processing and immune presentation. A DNA plasmid with five T-cell epitopes derived from ESAT-6, Ag85B, MTB10.4, PPE25 and PE19 proteins of H37Rv strain of M. tb genetically inserted into HSP65 backbone was constructed and designated as pPES. After confirmation of its in vitro expression efficiency, pPES DNA was i.m. injected into C57BL/6 mice with four doses of 50 mu g DNA followed by mycobacterial challenge 4 weeks after the final immunization. It was found that pPES DNA injection maintained the ability of HSP65 backbone to induce specific serum IgG. ELISPOT assay demonstrated that pPES epitope-scaffold construct was significantly more potent to induce IFN-(+) T response to five T-cell epitope proteins than other DNA constructs (with epitopes alone or with epitope series connected to HSP65), especially in multi-functional-CD4(+) T response. It also enhanced granzyme B+ CTL and IL-2(+) CD8(+) T response. Furthermore, significantly improved protection against Mycobacterium bovis BCG challenge was achieved by pPES injection compared to other DNA constructs. Taken together, HSP65 scaffold grafting strategy for multi-epitope DNA vaccine represents a successful example of rational protein backbone engineering design and could prove useful in TB vaccine design.
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Objective: The aim of the work described here was to evaluate the feasibility of superb microvascular imaging (SMI) and vascular endothelial growth factor receptor 2 (VEGFR2)-targeted microbubble (MBVEGFR2)-based ultrasound molecu...
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Objective: The aim of the work described here was to evaluate the feasibility of superb microvascular imaging (SMI) and vascular endothelial growth factor receptor 2 (VEGFR2)-targeted microbubble (MBVEGFR2)-based ultrasound molecular imaging (USMI) for visualizing microvessels in cervical cancer.Methods: Hela cells were used to establish subcutaneous cervical cancer models. SMI and MBVEGFR2-based USMI were performed, and the results were compared with intratumoral microvessel density (MVD) in four groups based on tumor diameter (<3 mm, 3-5 mm, 5-7 mm and >= 7 mm). The vascularization index (VI, %) was evaluated for SMI, and the normalized intensity difference (NID) for USMI.Results: Tumors with diameters ranging from 3 to 5 mm had the highest VI (39.07 +/- 1.58) in SMI, and VI significantly decreased with increasing tumor size (all p values <0.001). The strongest signal intensity was observed in very early tumors (d < 3 mm: 43.80 +/- 3.58%) after MBVEGFR2 administration; the NID gradually decreased with increasing diameter of tumors (all p values = 0.007). However, no significant differences were observed in NID after administration of non-targeted (control) microbubbles (MBCon) (all p values = 0.125). MBVEGFR2-based USMI had the strongest correlation with MVD in displaying microvessels of cervical cancer compared with SMI and MBCon (R-2 = 0.78 vs. R-2 = 0.40 and R-2 = 0.38).Conclusion: These findings validate the superiority and accuracy of MBVEGFR2-based USMI for microvessel imaging and monitoring of angiogenesis in cervical cancer compared with SMI and MBCon. Nonetheless, SMI remains an alternative to microvessel imaging when ultrasonic contrast agent use is contraindicated.
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Mine lands are an environmental concern worldwide because of their potential strong negative impact on water and soil quality. A field study was conducted to assess the use of a dry flue gas desulfurization (FGD) product for recla...
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Mine lands are an environmental concern worldwide because of their potential strong negative impact on water and soil quality. A field study was conducted to assess the use of a dry flue gas desulfurization (FGD) product for reclamation of an abandoned surface coal mine in Ohio. The FGD product was an atmospheric fluidized bed combustion residue and was applied to the graded mine site at 280 Mg ha(-1), both alone and in combination with 112 Mg ha(-1) yard waste compost, and was compared with conventional reclamation with 20 cm of borrow soil plus 157 Mg ha(-1) of agricultural limestone. A grass-legume sward was planted, and soil physical and chemical properties and beta-glucosidase activity were measured over both short- (1-4 yr) and long-term (15-17 yr) periods following reclamation. Soil pH at 0- to 20-cm depth increased from 3.1 to approximately neutral and was sustained at this level for 15 yr. Compared with the conventional reclamation, extractable Ca, S, B, and Zn concentrations at 0- to 20-cm depth were generally increased by the treatments with FGD product, while other extractable trace metals measured were generally not increased in short-or long-term measurements. Seventeen years after reclamation, b-glucosidase activity had increased in all three treatments at 0- to 5- and 5- to 10-cm depths compared with an adjacent untreated area. Furthermore, beta-glucosidase activity more than doubled in the treatments with FGD product compared with the conventional soil treatment at 0- to 5-cm depth. These results suggest that the use of high lime FGD products for reclamation of acid coal mine lands can provide effective long-term reclamation.
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Petroleum hydrocarbon pollution is a global problem. However, the effects of different petroleum pollution levels on soil microbial communities and ecological functions are still not clear. In this study, we analyzed the changes i...
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Petroleum hydrocarbon pollution is a global problem. However, the effects of different petroleum pollution levels on soil microbial communities and ecological functions are still not clear. In this study, we analyzed the changes in microbial community structures and carbon and nitrogen transformation functions in oil-contaminated soils at different concentrations by chemical analysis, high-throughput sequencing techniques, cooccurrence networks, and KEGG database comparison functional gene annotation. The results showed that heavy petroleum concentrations (petroleum concentrations greater than 20,000 mg kg(-1)) significantly decreased soil microbial diversity (p = 0.01), soil microbiome network complexity, species coexistence patterns, and prokaryotic carbon and nitrogen fixation genes. In medium petroleum contamination (petroleum concentrations of between 4000 mg kg(-1) and 20,000 mg kg(-1)), microbial diversity (p > 0.05) and carbon and nitrogen transformation genes showed no evident change but promoted species coexistence patterns. Heavy petroleum contamination increased the Proteobacteria phylum abundance by 3.91%-57.01%, while medium petroleum contamination increased the Actinobacteria phylum abundance by 1.69%0.26%. The results suggested that petroleum concentrations played a significant role in shifting soil microbial community structures, ecological functions, and species diversities.
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