ROS-Mediated Enamel Formation Disturbance Characterized by Alternative Cervical Loop Cell Proliferation and Downregulation of RhoA/ROCK in Ameloblasts.

Reactive oxygen stress (ROS) is generally accepted as a signal transducer for coordinating the growth and differentiation of tissues and organs in the oral and maxillofacial region. Although ROS has been confirmed to affect the development of enamel, it is not yet known that the specific mechanism of ROS accumulation induced enamel defects. Given the lack of knowledge of the role of ROS in enamel, the aim of the study is to determine how oxidative stress affects cervical cells and ameloblast cells. Using SOD1 knockout mice, we identified a relationship between ROS fluctuations and abnormal enamel structure with HE staining, micro-CT, and scanning electron microscope. Increased ROS induced by H2O2, certified by the DCFH probe, has resulted in a dual effect on the proliferation and differentiation of cervical cells, indicating a higher tendency to proliferate at low ROS concentrations. Ameloblasts transfected with SOD1 siRNA showed a significant reduction of RhoA and ROCK. This study investigates for the first time that SOD1-mediated ROS accumulation disrupted normal enamel structure through alternative cervical loop cell proliferation and downregulation of RhoA and ROCK in ameloblasts, demonstrating the convoluted role of ROS in monitoring the progress of enamel defects.

Research on the relationship between fiscal decentralization and environmental management efficiency under competitive pressure: evidence from China.

Taking industrial waste gas control as an example, this study explores the impact of fiscal decentralization on the efficiency of local governments' environmental governance under the pressure of competition, and analyzes the role of competition among local governments and support for R&D activities. The results demonstrate that fiscal decentralization can significantly promote the efficiency of local governance on control of waste gas, and this positive effect is mainly realized through the support from local government for R&D activities. As for the influence of inter-governmental competitions, only the competition in terms of governance efficiency delivers a significant U-shaped impact, and competition in expenditure scale and economy area weakly inhibits the positive influence of decentralization, meaning that the evaluation system centered on economic growth and the imitation strategy of local expenditure will not lead to a great decline in the efficiency of the use of environmental governance. Overall, this study suggests that further fiscal decentralization, emphases on government support for R&D activities, and enhanced environmental assessment in official evaluation are all the important directions for boosting the efficiency of governance.

Relationships Between Achievement Goal Orientations, Learning Engagement, and Academic Adjustment in Freshmen: Variable-Centered and Person-Centered Approaches.

Academic adjustment is a principal determining factor of undergraduate students' academic achievement and success. However, studies pay little attention to freshmen's antecedent variables of academic adjustment. This study aimed to examine the mechanisms underlying the relationship between achievement goal orientations and academic adjustment in freshmen using variable- and person-centered approaches. A sample of 578 freshmen (aged 18.29±1.04years, 58.5% female) completed questionnaires on achievement goal orientations, learning engagement, and academic adjustment. Latent profile analysis of achievement goal orientations revealed four groups: low-motivation (11.1%), approach-oriented (9.5%), average (52.8%), and multiple (26.6%). In the mediating analysis, results of the variable-centered approach showed that learning engagement mediated the effects of the mastery-approach and performance-avoidance goals on academic adjustment. For the person-centered approach, we selected the average type as the reference profile, and the analysis revealed that compared with the reference profile, learning engagement partially mediated the link between the approach-oriented profile and academic adjustment. The current study highlights the important role that achievement goal orientations and learning engagement play in academic adjustment. We discuss the implications and limitations of the findings.

The Dual Effects of Reactive Oxygen Species on the Mandibular Alveolar Bone Formation in SOD1 Knockout Mice: Promotion or Inhibition.

The status of reactive oxygen species (ROS) correlates closely with the normal development of the oral and maxillofacial tissues. Oxidative stress caused by ROS accumulation not only affects the development of enamel and dentin but also causes pathological changes in periodontal tissues (periodontal ligament and alveolar bone) that surround the root of the tooth. Although previous studies have shown that ROS accumulation plays a pathologic role in some oral and maxillofacial tissues, the effects of ROS on alveolar bone development remain unclear. In this study, we focused on mandibular alveolar bone development of mice deficient in superoxide dismutase1 (SOD1). Analyses were performed using microcomputerized tomography (micro-CT), TRAP staining, immunohistochemical (IHC) staining, and enzyme-linked immunosorbent assay (ELISA). We found for the first time that slightly higher ROS in mandibular alveolar bone of SOD1(-/-) mice at early ages (2-4 months) caused a distinct enlargement in bone size and increased bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and expression of alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2), and osteopontin (OPN). With ROS accumulation to oxidative stress level, increased trabecular bone separation (Tb.Sp) and decreased expression of ALP, Runx2, and OPN were found in SOD1(-/-) mice at 6 months. Additionally, dosing with N-acetylcysteine (NAC) effectively mitigated bone loss and normalized expression of ALP, Runx2, and OPN. These results indicate that redox imbalance caused by SOD1 deficiency has dual effects (promotion or inhibition) on mandibular alveolar bone development, which is closely related to the concentration of ROS and the stage of growth. We present a valuable model here for investigating the effects of ROS on mandibular alveolar bone formation and highlight important roles of ROS in regulating tissue development and pathological states, illustrating the complexity of the redox signal.