Indirect Effects Research Articles

마음챙김이 초등학생의 불안에 미치는 영향

Objectives This study aim to explore the relationship between mindfulness and anxiety and the mediating effects of emotion regulation and worry on the relationship between mindfulness and anxiety. Methods The data were analyzed from 289 elementary school children in Seoul. Reliability analysis, technical sta-tistics, correlation analysis, and mediating effect analysis of each scale were conducted using the SPSS 18.0 and PROCESS Macro Model 4.2. Results Research results were as follows. First, the correlation between mindfulness and anxiety were significant, and regression analysis showed that mindfulness significantly predicted anxiety. Second, the mediating effect of emotion regulation and worry were significant in the relationship between mindfulness and anxiety. Conclusions This study was verified that children's mindfulness is a useful variable that directly affects anxiety re-duction and indirectly through emotional control and worry. It also provides useful information for making mindful-ness-based interventions. Considering the results that the indirect effect through worry was greater than the di-rect effect of mindfulness on anxiety, it suggests the need to include mindfulness activities on children's worry.

Negative life events and suicidality among adolescents in Western China: the mediating effect of depressive symptoms and the moderating effect of self-esteem.

To investigate the mediating role of depressive symptoms in the relationship between negative life events (NLEs) and suicidality, as well as to test the moderating effect of self-esteem in the mediation model. A total of 3,003 adolescents from Han, Tibetan, and Yi ethnic groups living in Western China were included in this study. Utilizing the structural equation model, a mediation model and a moderated mediation model were constructed. The presence of NLEs was positively associated with suicidality (β = 0.17, p < 0.001). Depressive symptoms partially mediated the relationship between NLEs and suicidality (indirect effect β = 0.19, p < 0.001). Self-esteem moderated both the antecedent and subsequent segments of the mediating paths of "NLEs → depressive symptoms → suicidality" and the direct relationship between NLEs and suicidality. Among adolescents with a low level of self-esteem, the mediating effect coefficient of depressive symptoms was higher at 0.18 (95% confidence interval (CI): 0.14-0.23), in contrast to adolescents with a high level of self-esteem, where the mediating effect coefficient of depressive symptoms was 0.04 (95% CI: 0.02-0.07). NLEs are directly associated with an increased risk of suicidality and indirectly related to suicidality by increasing the risk of depressive symptoms among adolescents. Self-esteem can moderate the mediating effect of depressive symptoms and the relationship between NLEs and suicidality. The intervention strategy for preventing suicidality among adolescents who have experienced NLEs should focus on reducing depressive symptoms and improving self-esteem.

부모의 학습지원과 지지적 학교환경이 초등학생의 학습태도에 미치는 영향

Objectives The purposes of this study were to specify variables related to convergence competency, and to ana-lyze the structural relationships among them. The purposes of this study were to specify variables related to con-vergence competency, and to analyze the structural relationships among them. Methods In this study, 1,145 children who responded to all related variables in the 12th and 13th data of the Korean Children's Panel were used as data. The structural equation model was analyzed to understand the struc-tural relationship between each variable, and the direct and indirect effects were verified through this. In addition, the mediating effect was verified using bootstrapping. Results There was no significant relationship between parents' learning support and elementary school students' learning attitude, and there was a positive relationship between the supportive school environment and learning attitude. Grit showed a complete mediating effect in the effect of parental learning support on learning attitude, and Grit showed a partial mediating effect in the effect of supportive school environment on learning attitude. Conclusions Parents' learning support and supportive environment had a positive effect on Grit, which improved the learning attitude. This study is expected to help parents, who are interested in their children's learning, support direction and school environment by examining the influence and path of parents‘, school variables and grit that can positively affect learning attitudes.

Neutral news from in- and out-party media and attitudes toward them: integration of expectancy violations theory and hostile media perceptions

ABSTRACT The contemporary U.S. media environment is characterized by a strong partisan divide. Both Democrats and Republicans express strong distrust in oppositional media and accuse them of showing partisan bias. Clearly, this public opinion climate is not helpful to a healthy democracy. Unlike the common wisdom, these news outlets do provide neutral political coverage. Based on propositions from expectancy violation theory and hostile media perceptions, we test the effects of exposure to neutral news from an out-party outlet on violation interpretation and attitudes toward oppositional media. An online experiment (N = 610) shows that exposure to neutral news from an out-party outlet leads to violation unexpectedness and valence for Democrats and violation valence for Republicans. We also find an indirect positive effect of exposure to neutral news on attitudes toward an out-party outlet through violation valence for Democrats and Republicans. Unlike what can be expected of hostile media perceptions, these effects are more noticeable for stronger partisans. Our study also reveals different patterns of partisan reactions to neutral news from in-party outlets. Theoretical implications are discussed.

Persistence and Variation of the Indirect Effects of COVID-19 Restrictions on the Spectrum of Notifiable Infectious Diseases in China: Analysis of National Surveillance Among Children and Adolescents From 2018 to 2021.

Beyond the direct effect of COVID-19 infection on young people, the wider impact of the pandemic on other infectious diseases remains unknown. This study aims to assess changes in the incidence and mortality of 42 notifiable infectious diseases during the pandemic among children and adolescents in China, compared with prepandemic levels. The Notifiable Infectious Disease Surveillance System of China was used to detect new cases and fatalities among individuals aged 5-22 years across 42 notifiable infectious diseases spanning from 2018 to 2021. These infectious diseases were categorized into 5 groups: respiratory, gastrointestinal and enterovirus, sexually transmitted and blood-borne, zoonotic, and vector-borne diseases. Each year (2018-2021) was segmented into 4 phases: phase 1 (January 1-22), phase 2 (January 23-April 7), phase 3 (April 8-August 31), and phase 4 (September 1-December 31) according to the varying intensities of pandemic restrictive measures in 2020. Generalized linear models were applied to assess the change in the incidence and mortality within each disease category, using 2018 and 2019 as the reference. A total of 4,898,260 incident cases and 3701 deaths were included. The overall incidence of notifiable infectious diseases decreased sharply during the first year of the COVID-19 pandemic (2020) compared with prepandemic levels (2018 and 2019), and then rebounded in 2021, particularly in South China. Across the past 4 years, the number of deaths steadily decreased. The incidence of diseases rebounded differentially by the pandemic phase. For instance, although seasonal influenza dominated respiratory diseases in 2019, it showed a substantial decline during the pandemic (percent change in phase 2 2020: 0.21, 95% CI 0.09-0.50), which persisted until 2021 (percent change in phase 4 2021: 1.02, 95% CI 0.74-1.41). The incidence of gastrointestinal and enterovirus diseases decreased by 33.6% during 2020 but rebounded by 56.9% in 2021, mainly driven by hand, foot, and mouth disease (percent change in phase 3 2021: 1.28, 95% CI 1.17-1.41) and infectious diarrhea (percent change in phase 3 2020: 1.22, 95% CI 1.17-1.28). Sexually transmitted and blood-borne diseases were restrained during the first year of 2021 but rebounded quickly in 2021, mainly driven by syphilis (percent change in phase 3 2020: 1.31, 95% CI 1.23-1.40) and gonorrhea (percent change in phase 3 2020: 1.10, 95% CI 1.05-1.16). Zoonotic diseases were not dampened by the pandemic but continued to increase across the study period, mainly due to brucellosis (percent change in phase 2 2020: 0.94, 95% CI 0.75-1.16). Vector-borne diseases showed a continuous decline during 2020, dominated by hemorrhagic fever (percent change in phase 2 2020: 0.68, 95% CI 0.53-0.87), but rebounded in 2021. The COVID-19 pandemic was associated with a marked decline in notifiable infectious diseases in Chinese children and adolescents. These effects were not sustained, with evidence of a rebound to prepandemic levels by late 2021. To effectively address the postpandemic resurgence of infectious diseases in children and adolescents, it will be essential to maintain disease surveillance and strengthen the implementation of various initiatives. These include extending immunization programs, prioritizing the management of sexually transmitted infections, continuing feasible nonpharmaceutical intervention projects, and effectively managing imported infections.

Maternal Sleep Quality and Executive Function are Associated with Perceptions of Infant Sleep.

This study examined the associations among maternal sleep quality, executive function, and perceptions of infant sleep in a sample of families recruited from human service and public health systems. Seventy-three mothers of infants 5-14 months old were included in the study. Mothers racially and ethnically identified as American Indian/Alaskan Native (4.1%), Asian (4.1%), Black/African American (12.3%), Latina (23.3%), more than one race (12.3%), Pacific Islander (1.4%), and White (42.5%). Mothers completed questionnaires assessing their own sleep (Pittsburgh Sleep Quality Index) and executive function (Behavior Rating Inventory of Executive Function) as well as their perceptions about their infant's sleep (Brief Infant Sleep Questionnaire). Results of the path analysis indicated significant direct effects among maternal sleep quality, executive function, and perceptions of infant sleep. Significant indirect effects were found such that poor maternal sleep quality was linked to poorer perceptions of infant sleep through maternal executive dysfunction, adjusting for infant sleep patterns, infant age, and maternal race and ethnicity. The current study highlights the potential role of maternal behavioral and cognitive factors in shaping mothers' perceptions about infant sleep. These findings support the need for health professionals and researchers to consider maternal sleep quality and executive function when addressing mothers' concerns about infant sleep.

Integrated Hfq-interacting RNAome and transcriptomic analysis reveals complex regulatory networks of nitrogen fixation in root-associated Pseudomonas stutzeri A1501.

Numerous experimental approaches often face challenges in distinguishing between direct and indirect effects of Hfq-mediated regulation. New technologies based on high-throughput sequencing are increasingly providing insight into the global regulation of Hfq in gene expression. Here, enhanced UV cross-linking immunoprecipitation coupled with high-throughput sequencing was employed to identify the Hfq-binding sites and potential targets in the root-associated Pseudomonas stutzeri A1501 and identify hundreds of novel Hfq-binding RNAs that are predicted to be involved in metabolism, environmental adaptation, and nitrogen fixation. In particular, we have shown Hfq interactions with various regulatory proteins' mRNA and their potential targets at the posttranscriptional level. This study not only enhances our understanding of Hfq regulation but, importantly, also provides a framework for addressing integrated regulatory network underlying root-associated nitrogen fixation.

창의적 자기효능감과 정서조절 및 창의적 성취간의 관계

Objectives The purpose of this study was to examine the indirect effects of creative self-efficacy on creative ach-ievement through emotion regulation strategies in dance majors, and to examine whether the effectiveness of emotion regulation strategies in mediating the relationship between creative self-efficacy and creative achieve-ment varies by dance experience level. Methods A total of 434 dance majors (46 males, 388 females, mean dance experience level: 7.35±3.79 years) re-sponded to questionnaires measuring creative self-efficacy, emotion regulation strategies, and creative achieve-ment, and the data were processed through mediation analysis and controlled mediation analysis using PROCESS version 4.0 for SPSS (Hayes, 2018). Results Creative self-efficacy positively influenced creative achievement directly as well as through emotion reg-ulation strategies. Furthermore, the effect of emotion regulation strategies on mediating the positive relationship between creative self-efficacy and creative achievement was stronger when the level of creative self-efficacy was high but the level of dance experience was low. We also found that the emotion regulation strategies that me-diate the positive relationship between creative self-efficacy and creative achievement are stronger when crea-tive self-efficacy is high but dance experience is low, and that the effect of creative self-efficacy on creative ach-ievement is stronger when college students with low creative self-efficacy have high dance experience. Conclusions The results suggest that it is important for college students majoring in dance to develop the ability to effectively manage their emotional experiences in order to be confident in their ability to effectively generate and perform creative ideas in order to solve problems and achieve goals during creative activities.

비대면 온라인 수업에서의 학습 참여도와 학생 만족도의 관계에 관한 실증적 연구

Objectives The purpose of this study is to empirically analyze the relationship between learning engagement and student satisfaction in a contactless online class environment. Methods The study employed regression analysis and text-based network analysis as research methods. Regression analysis was used to quantitatively measure the direct impact of learning engagement factors on stu-dent satisfaction. Text-based network analysis was used to explore the indirect effects on satisfaction by identify-ing information flow and centrality within the learning community. Results The analysis revealed a positive correlation between course completion rates and the frequency of the keyword ‘hard work’ in lecture comments, as well as the number of completed quiz submissions. However, the number of lectures and viewing time did not have a significant impact. The network analysis indicated that key-words such as ‘fun,’ ‘informative,’ ‘quiz,’ and ‘completion’ were central, suggesting that learner interaction is a crucial factor in satisfaction. Conclusions In conclusion, this study suggests that promoting interaction among learners and encouraging their active participation in course design can improve the efficiency and satisfaction of virtual classes. The empirical data provided here is expected to contribute to the improvement of educational technology.

Predictors and Mechanisms of Resilience for High School Students with ADHD: A Prospective Longitudinal Study.

Attention-deficit/hyperactivity disorder (ADHD) has primarily been studied from a deficit-focused perspective. However, there are individuals with ADHD who exhibit resilience or a pattern of positive adaptation despite the risks associated with their diagnosis. The present study evaluated whether peer acceptance predicted resilience for adolescents with ADHD and if self-efficacy or a stress-is-enhancing mindset served as mechanisms of those relations. Participants included 113 comprehensively evaluated adolescents with ADHD (67% male) across three time-points (10th-12th grade). Mediation analyses revealed higher T1 peer acceptance significantly predicted higher resilience (β = 0.24) 1.5-2years later, with higher T2 self-efficacy (β = 0.08) demonstrating a significant indirect effect of the association. A stress-is-enhancing mindset directly predicted resilience (β = 0.15) but was not associated with peer acceptance nor mediated the association between peer acceptance and resilience. Present results are the first to provide longitudinal evidence for peer acceptance, self-efficacy, and a stress-is-enhancing mindset as important for promoting resilience among adolescents with ADHD.

Exploring the Association Between Loneliness, Subjective Cognitive Decline, and Quality of Life Among Older Thai Adults: A Convergent Parallel Mixed-Method Study.

Examining the rising prevalence of subjective cognitive decline as an early indicator of dementia in adults, this study investigates its complex interaction with loneliness and quality of life in individuals with preclinical dementia. Using a convergent parallel mixed-method approach, we employed Structural Equation Modeling on a cohort of 149 older adults. Qualitative insights were derived from focused group discussions and in-depth semi-structured interviews with a cohort of 23 older adults. Loneliness emerges as a pivotal contributor, exerting a discernible partial indirect effect on quality of life through subjective cognitive decline (indirect effect = -0.145, p = .006). Noteworthy differentials surfaced, with the impact of subjective cognitive decline on quality of life heightened in those with chronic diseases (△χ2 = 6.139, p = .013). Loneliness, wielding a palpable impact, intricately interlaces with quality of life, the nexus of which is intricately mediated by subjective cognitive decline.

The influence of electronic word of mouth on green cosmetics purchase intention: evidence from young Vietnamese female consumers

Purpose This study aims to examine the direct and indirect influence of electronic word of mouth (eWOM) on green cosmetics purchase intention of young Vietnamese female consumers through health concern, environmental concern and the theory of planned behavior (TPB) factors. Design/methodology/approach Data were collected from a survey of Vietnamese young female consumers that were analyzed using a partial least squares structural equation modeling. Findings The results reveal that eWOM has a direct effect on consumers’ purchase intention of green cosmetics. Among TPB factors, attitude was a greater influential predictor of purchase intention than subjective norms. However, the influence of perceived behavioral control on purchase intention was not supported. There were significant indirect effects of eWOM on purchase intention through the mediation of health concern, environmental concern and attitude. Practical implications Therefore, the findings of this study are relevant for marketers and managers as they provide valuable insights into understanding the motivational factors of consumers’ green cosmetics purchase intention. The results highlighted that eWOM could increase young female consumers’ environmental concern and health concern, which, in turn, influence a positive attitude toward green cosmetics. Hence, eWOM is a powerful vehicle for environmental and health messages; also, it can be an important channel of sensitization toward environmental and health issues and motivation of proenvironmental behavior and healthy lifestyle. Originality/value The study contributed to the literature by confirming the utility of the TPB model in predicting young women’s green cosmetics purchases in the context of Vietnam, an emerging market, which has largely been overlooked in the literature. The findings show that eWOM has a direct influence on green cosmetics purchase intentions of young Vietnamese female consumers and indirectly eWOM through health concern, environmental concern and two TPB factors (attitude and subjective norms).

Urban traffic-parking system dynamics model with macroscopic properties: a comparative study between Shanghai and Zurich

Analyzing the dynamics of parking traffic can better represent the real dynamic states of road networks, thereby allowing for a deeper analysis of the parking system’s impact. This paper comparatively investigates the impact of parking policies on two traffic networks with different infrastructure, socio-economic, and policy characteristics. Parking space, average parking duration, and parking fee policies were analyzed as a function of cruising distances and cruising time with indirect effects on traffic emissions. Empirically, the system dynamics model application is tested and validated with the macroscopic data from two central business districts (CBDs) in Shanghai (Xujiahui area) and Zurich (Bahnhofstrasse area). Results showed Bahnhofstrasse CBD is more sensitive against the policy shifts with relatively higher elasticity and indicated greater responsiveness in aggregating traffic emissions when compared with Xujiahui CBD. The findings of this study may provide an overall framework to empirically assess the performance of different traffic conditions and strategies on urban parking systems.

Early survival in Atlantic salmon is associated with parental genotypes at loci linked to timing of maturation.

Large effects loci often contain genes with critical developmental functions with potentially broad effects across life-stages. However, the life-stage-specific fitness consequences are rarely explored. In Atlantic salmon, variation in two large-effect loci, six6 and vgll3, is linked to age at maturity, and several physiological and behavioural traits in early life. By genotyping the progeny of wild Atlantic salmon that were planted into natural streams with nutrient manipulations, we tested if genetic variation in these loci is associated with survival in early life. We found that higher early life survival was linked to the genotype associated with late maturation in the vgll3, but with early maturation in the six6 locus. These effects were significant in high-nutrient, but not in in low-nutrient streams. The differences in early survival were not explained by additive genetic effects in the offspring generation, but by maternal genotypes in the six6 locus, and by both parents' genotypes in the vgll3 locus. Our results suggest that indirect genetic effects by large-effect loci can be significant determinants of offspring fitness. This study demonstrates an intriguing case of how large-effect loci can exhibit complex fitness associations across life stages in the wild and indicates that predicting evolutionary dynamics is difficult.

The effect of justice sensitivity on malevolent creativity: the mediating role of anger and the moderating role of emotion regulation strategies

Backgroundthe AMORAL model emphasizes the close connection of individuals’ belief system and malevolent creativity. Belief in a just world theory (BJW) states that people have a basic need to believe that the world they live in is just, and everyone gets what they deserve. Therefore, justice matters to all people. Justice sensitivity, as one of individual trait, has been found associated with negative goals. However, relevant studies have not tested whether justice sensitivity can affect malevolent creativity and its psychological mechanisms. Additionally, researchers have found that both anger and emotion regulation linked with justice sensitivity and malevolent creativity, but their contribution to the relationship between justice sensitivity and malevolent creativity remained unclear. The current study aims to explore the influence of justice sensitivity on malevolent creativity, the mediating effect of trait anger/state anger on the relationship between justice sensitivity and malevolent creativity, and the moderating effect of emotion regulation on this mediating effect.MethodsA moderated mediating model was constructed to test the relationship between justice sensitivity and malevolent creativity. A sample of 395 Chinese college students were enrolled to complete the questionnaire survey.ResultsJustice sensitivity positively correlated with malevolent creativity, both trait anger and state anger partly mediated the connection between justice sensitivity and malevolent creativity. Moreover, emotion regulation moderated the indirect effect of the mediation model. The indirect effect of justice sensitivity on malevolent creativity through trait anger/state anger increased as the level of emotion regulation increased. The results indicated that justice sensitivity can affect malevolent creativity directly and indirectly through the anger. The level of emotion regulation differentiated the indirect paths of justice sensitivity on malevolent creativity.ConclusionsJustice sensitivity and malevolent creativity was mediated by trait anger/state anger. The higher sensitivity to justice, the higher level of trait anger/state anger, which in turn boosted the tendency of malevolent creativity. This indirect connection was moderated by emotion regulation, individuals with high emotion regulation are better able to buffer anger from justice sensitivity.

Research on consumers' purchase intention of cultural and creative products-Metaphor design based on traditional cultural symbols.

Chinese traditional cultural symbols possess great aesthetic and cultural value, and are widely utilized in product design. In this study, we explore the relationship between metaphor design based on traditional cultural symbols, customer experience and cultural identity, and further estimate how these three variables stimulate consumers' perceived value to generate consumers' purchase intention. Based on existing traditional cultural literature and Stimulus-organism-response theory (SOR), we proposed a theoretical research model to characterize the relationship among metaphor design based on traditional cultural symbols, customer experience, cultural identity, perceived value and consumers' purchase intention. A research survey was conducted and 262 questionnaires were collected in total with 241 valid. We used Smart PLS graph version 3.0 for data analysis. Results indicate that the cognition of metaphor design based on traditional cultural symbols and customer experience has a direct and significant impact on the emotional value thereby, eliciting consumers' purchase intention, metaphor design based on traditional cultural symbols is directly and indirectly (i.e., through customer experience or perceived value) positively associated with consumers' purchase intention, also customer experience is directly and indirectly (i.e., through perceived value) associated with consumer purchase intention, cultural identity mediates the indirect effect of customer experience and perceived value on purchase intention, the moderating role of cultural identity between customer experience and perceived value is not significant. Our findings help to expand the existing literature on consumer purchase intentions by rationally using traditional cultural symbols in the product metaphor design.

Anxiety mediates association between sex and jaw function limitation in temporomandibular disorder patients from China

AimThe objective of this study is to explore the relationship between sex and jaw function and to test whether anxiety mediates the causal relationship between sex and jaw function in temporomandibular disorders (TMDs) patients.MethodsA total of 488 participants with TMD were included in the analysis. Demographic data were collected. Generalized anxiety symptoms and anxiety severity were initially assessed using the GAD-7 questionnaire. And jaw function limitation was measured using the JFLS-8 scale. A directed acyclic graph (DAG) was used in this study to evaluate the hypotheses. Mediation analysis was conducted to explore causality and to calculate the total effect, natural direct effect (NDE) and natural indirect effect (NIE).ResultsIn TMD patients, there was a significant association between female and jaw function (r = 0.17, p &amp;lt; 0.001), female and anxiety (r = 0.15, p = 0.002), anxiety and jaw function (r = 0.35, p &amp;lt; 0.001). In addition, sex can directly lead to differences in impaired jaw function (NDE: 3.719, 95% CI: 1.619–5.828, p &amp;lt; 0.001), and can also be causally related to jaw function through anxiety (NIE: 1.146, 95% CI: 0.267–2.024, p = 0.011). And the total effect was 4.865 (95% CI, 2.709–7.029, p &amp;lt; 0.001).ConclusionA causal mechanism was found that anxiety acts as a mediator of sex effects on jaw function. Therefore, psychological factors need to be taken into account in the treatment of female TMD patients. Further clinical trials are needed to explore whether psychotherapy is more beneficial to improve jaw function in female TMD patients.

A tale of two paths to vaccine acceptance: self-interest and collective interest effect, mediated by institutional trust, and moderated by gender

Coronavirus and other prevailing viruses continue to remain a health threat and challenge the efforts of institutions to promote vaccination acceptance. The current study’s aim is to propose a conceptual framework explaining the role of individual motivators (such as self-interest and collective interest) in shaping attitudes toward vaccination while emphasizing the pivotal role of institutional trust as a mediator and gender as a moderator. Data were collected via an online panel survey among Israelis (N = 464), and SEM statistics were used to test the model empirically. The path analysis model supports the positive direct effect of collective interest and the negative effect of self-interest. Additionally, it shows an indirect effect through the mediation effect of institutional trust and gender moderation. Therefore, institutional trust may significantly influence self-interest people’s attitudes toward vaccines. Furthermore, since females process information more comprehensively, their developed trustworthiness in institutions has an increased impact on vaccine acceptance. Theoretical and practical implications are discussed.

The Influence of Leadership Style and Interpersonal Communication on Employee Performance with Work Morale as an Intervening Variable at PT. Surya Andalan Primatama Mukomuko

This research aims to determine the influence of leadership style and interpersonal communication on employee performance with work enthusiasm as an intervening variable at PT. Surya Andalan Primatama Mukomuko. The population and research sample were 110 respondents with a sampling technique using the total sampling method. The data processing method uses Structure equation modeling (SEM) with the SmartPLS tool. The research results show that there is a significant positive influence of leadership style and interpersonal communication on work morale. Leadership style has a positive and significant effect on employee performance, and interpersonal communication has a positive and insignificant effect on employee performance. Work morale has a positive and significant influence on employee performance. For indirect effects, this research also reveals that leadership style and interpersonal communication influence employee performance through work morale

Bioreactor Expansion Affects Microbial Succession of Mixotrophic Acidophiles and Bioremediation of Cadmium-Contaminated Soils

Microbial scale-up cultivation is the first step to bioremediating cadmium (Cd)-contaminated soils at the industrial scale. However, the changes in the microbial community as the bioreactor volume expands and their associations with soil Cd removal remain unclear. Herein, a six-stage scale-up cultivation process of mixotrophic acidophiles was conducted, scaling from 0.1 L to 10 m3, to remediate Cd-contaminated soils. The findings showed that bioreactor expansion led to a delay in sulfur and glucose oxidations, resulting in a reduced decline in solution pH and cell density. There were minimal differences observed in bacterial alpha-diversity and community structure as the bioreactor volume increased, except for the 10 m3 scale. However, bioreactor expansion decreased fungal alpha-diversity, changed the community structure, and simplified fungal community compositions. At the family level, Acidithiobacillaceae and Debaryomycetaceae dominated the bacterial and fungal communities throughout the scale-up process, respectively. Correlation analysis indicated that the indirect effect of mixotrophic acidophiles played a significant role in soil Cd removal. Bacterial community shifts, driven by changes in bioreactor volume, decreased the pH value through sulfur oxidation, thereby indirectly enhancing Cd removal efficiency. This study will contribute to the potential industrial application of mixotrophic acidophiles in bioremediating Cd-contaminated soils.