Fujian Jiangxia University

To investigate the interaction between carbonation and chloride ions on the durability of single-phase nickel slag geopolymer mortar, three experimental conditions were designed: (A) chloride ion penetration followed by carbonation, (B) carbonation followed by chloride ion penetration, and (C) carbonation, chloride ion penetration, and wet-dry cycles. Macro-performance was assessed through compressive strength, pH values, and chloride ion concentration, while microstructural mechanisms were analyzed using XRD, TG-DTG, and SEM. Results showed that chloride crystallization delayed carbonation, while carbonation products enhanced resistance to chloride penetration. The synergy of carbonation and wet-dry cycles accelerated chloride transport, thickening the surface convection zone. XRD and TG-DTG analyses confirmed the formation of hydrotalcite-like phases due to the high MgO content in nickel slag. No Friedel’s salt was detected, suggesting chloride ions were captured mainly through physical adsorption of the amorphous gel phase. Highlights Carbonation was delayed by chloride crystallization, while chloride resistance was enhanced by pre-carbonation. Chloride transport was accelerated by the synergy between carbonation and cyclic wet-dry exposure. Hydrotalcite-like phases were identified, while chloride was primarily through physical adsorption.

The intestinal microbiota is a complex and dynamic community that contributes to digestion and plays a crucial role in regulating immune health. In this study, post-metamorphic bullfrogs (Aquarana catesbeiana) at different ages (1, 2, 3, and 4 months) were investigated. Growth performance assessment, intestinal histomorphological analysis, and 16S rRNA sequencing were employed to systematically examine the dynamics and diversity of microbial communities in the small intestinal segments (duodenum, jejunum, and ileum). Results showed that bullfrog growth indices increased with age, with faster body weight gain during 2–3 months; notably, this was significantly positively correlated with intestinal morphological development (villus height and muscle layer thickness) (p < 0.05). In terms of microbial composition, Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, and Actinobacteria were dominant phyla, while different intestinal segments harbored specific dominant genera. Among them, Cetobacterium was consistently detected throughout the growth period, suggesting it is likely the core symbiont in bullfrog intestines. Moreover, microbiota function varied with growth stages: at 1–2 months, Bifidobacterium and Cetobacterium synergistically participated in immune regulation and basic metabolism, whereas at 3–4 months, Weissella, Lactococcus, and Bacteroides became dominant, with their functions shifting toward efficient energy conversion. Additionally, Alpha diversity analysis showed a decreasing trend in the Simpson index with development, while Beta diversity analysis revealed that microbiota composition was similar among different intestinal segments at the same age but that significant differences existed in each segment during 2–3 months. Overall, this study reveals the specific distribution characteristics of probiotic microbiota in bullfrogs at different growth stages, thereby providing a scientific basis for screening growth-promoting frog-derived probiotics that match host physiological traits.

BackgroundRapid urbanization has intensified psychological stress among urban residents. As highly accessible forms of urban green space, small urban parks play a vital role in fostering psychological resilience and restorative experiences. However, in high-density cities such as Fuzhou, the underlying restorative mechanisms of different types of small parks—along with the moderating effects of gender and specific landscape elements—remain insufficiently understood.MethodsThis study adopted a multi-method approach, incorporating psychological assessment via the Perceived Restorativeness Scale (PRS), eye-tracking techniques, and physiological measurements including skin conductance level (SCL) and the low-frequency/high-frequency (LF/HF) ratio of heart rate variability. A total of 55 participants from Fuzhou were exposed to four distinct types of small urban parks—pocket parks, linear waterfront parks, community parks, and small comprehensive parks—to evaluate their restorative outcomes.ResultsBoth park type and gender exerted significant effects on restorative perceptions and physiological responses (p < 0.001). Small comprehensive parks achieved the highest PRS scores in the dimensions of being away, fascination, and compatibility, while presenting the lowest SCL and LF/HF ratios, indicative of the strongest overall restorative effects. Female participants reported higher perceived restorativeness and exhibited lower SCL values compared with male participants. The proportion of gaze fixation on vegetation was identified as the most salient positive predictor of both restorative experience and physiological relaxation. Conversely, fixation on artificial facilities and the sky showed negative predictive relationships in certain park types, while water features and traditional architectural elements displayed context-dependent positive influences.ConclusionThe restorative effects of small urban parks are jointly influenced by park type, gender, and landscape elements. Small comprehensive parks demonstrated superior performance—primarily due to their diverse and integrated natural landscapes—whereas linear waterfront parks were particularly effective in physiological regulation. Pocket parks and community parks provided comparatively weaker restorative effects, likely constrained by limited amenities and spatial configurations. Females were more sensitive to psychological perceptions (e.g., “being away,” “fascination”) and physiological responses. Natural elements (e.g., multi-layered vegetation, water bodies) served as core drivers of stable restoration, whereas the role of artificial facilities was context-dependent: traditional architecture enhanced cultural identity, while dense modern facilities potentially increased cognitive load.

Abstract Titanium phosphate (TiP) exhibits significant potential for the removal of U(VI) from aqueous solutions. In this study, tetra-n-butyl titanate (TBOT) and phosphoric acid were employed as titanium and phosphorus sources, respectively, and the P/Ti ratio was varied during the hydrothermal synthesis. Both amorphous and α-type TiPs were successfully synthesized, and their physicochemical properties at different P/Ti ratios were characterized using XRD, FTIR, SEM, zeta potential, and TG analysis. The effects of pH and P/Ti ratio on adsorption performance were systematically investigated, revealing that all TiPs achieved maximum adsorption capacity at pH 7.0. The adsorption behavior conformed to the Langmuir model, with a theoretical maximum adsorption capacity of 266.4 mg g −1 at a P/Ti ratio of 2. In the presence of multiple competing ions, amorphous TiP demonstrated higher selectivity for U(VI) compared to α-type TiP. Mechanistic studies indicated that U(VI) adsorption primarily occurs via surface complexation and ion exchange processes on the TiP surface. Overall, the adsorption efficiency of U(VI) can be effectively optimized by adjusting the P/Ti ratio in TiP.

Case-based teaching and the value of scaffolding in assisting students to solve the problem in case studies has been widely acknowledged. However, there have been few studies mapping out how teachers practise scaffolding in their naturally occurring case-based teaching. To address this knowledge gap, the present study explores, through multimodal interaction analysis, the ways two business English teachers practised scaffolding in their case-based teaching to support students’ problem-solving process. By employing a primarily qualitative method of video observations paired with teachers’ self-reflections on their teaching (yet integrating a quantitative layer through targeted data analysis), the study reveals that both teachers made full use of eight communicative modes of spoken language, print, spatial position, movement, gesture, gaze, head movement and facial expression to realise their scaffolding strategies; however, their scaffolding practice exerted distinct influences on students’ working memory processing during problem-solving. The findings indicate that teachers need, when scaffolding students’ problem-solving process in case-based teaching, to be aware of the significance of the appropriate choice and coordinated use of communicative modes. It yields important implications for promoting the critical semiotic awareness of pre-service and in-service teachers across different subject disciplines, educational settings, and cultural contexts in their case-based teaching.

With the extensive growth of the web as well as cellular networks, secure multimedia transmission through cellular networks is needed. Currently, fifth-generation (5G) cellular networks are utilized to perform secure multimedia transmission. Numerous studies have been conducted to design efficient resource allocation approaches for secure video transmission in 5G cellular networks. However, this approach does not offer complete video security related to security against dynamic eavesdroppers or patent defilements. Thus, a resource allocation algorithm named Tasmanian devil whale optimization (TDWO) is introduced for secure video transmission in 5G networks. Here, the recorded educational videos are considered and are transmitted over 5G network transmission resources initially. The resources in 5G networks are allocated via the TDWO model by considering fitness parameters such as the data rate, achievable data rate, and quality of experience (QoE). Here, the deep convolutional neural network (DCNN) model is deployed for the prediction of the QoE in resource allocation. Moreover, extensive experiments are performed to identify the resource allocation performance of the designed TDWO model. The experimental results prove that the TDWO resource allocation algorithm yields significant experimental outcomes, with throughput, bit error rate (BER), QoE and fitness values of 25.557 Mbps, 0.021, 18.332 and 0.013, respectively.