GCI Science & Technology (China)

As an important and rapidly developing agricultural industry worldwide, oyster aquaculture helps mitigate the coastal eutrophication by denitrification, a process which produces nitrous oxide (N2O). Yet it is not presently possible to quantify the N2O flux associated with oyster farming in transitional water bodies. Incubations using nitrate and nitrite as the substrates complemented with functional gene screening confirm net anaerobic N2O production in oyster digestive tract. The N2O production rate could be positively regulated by nitrate and nitrite availabilities and temperature. Surprisingly, oyster’s digestive tract is an unexpected N2O source due to the inability of N2O reduction to N2. In comparison, the oyster shell-associated biofilm and attached particulate matter (APM) can perform complete denitrification, thus offsetting net N2O production by digestive tract. Such a net N2O consumption is more effective under lower oxygen condition. However, high availabilities of nitrite and nitrate in the water column may lower the N2O sink capacity, even ceasing N2O consumption. This study elucidates a modular N2O turnover that is specific to the compartments inside and outside of oysters, providing insights into the environmental controls about dynamic N2O source or sink associated with shellfish-microbe interactions.

DeepSeek has emerged as a prominent representative of China’s domestic large language models(LLMs), attracting widespread public attention and generating diverse discussions on social media since its release. To systematically examine public sentiment and thematic concerns surrounding DeepSeek, this study analyzes 86,008 Weibo posts collected between January 19 and March 22, 2025. After data cleaning, 59,679 valid entries were retained. A mixed-method approach was adopted, combining Latent Dirichlet Allocation (LDA) for topic modeling and a fine-tuned BERT-based classifier for sentiment analysis. The BERT model, fine-tuned on 10,000 hand-labeled posts, achieved an accuracy of 82% and was subsequently applied to the remaining unlabeled data. Topic modeling revealed nine major themes in public discourse, including chip innovation and industrial transformation, smart device ecosystem, and China–US technological competition. Sentiment analysis showed that 46.3% of the posts expressed a positive attitude, reflecting public endorsement of DeepSeek’s domestic innovation and application potential, although concerns about information security, technical feasibility, and international political dynamics were also evident. Additionally, major events significantly influenced emotional fluctuations, with peaks in public attention observed on January 27 and March 19. These findings offer empirical insights for policymakers, developers, and the broader public into public acceptance, key concerns, and potential risks associated with emerging AI technologies, and support the formulation of informed strategies for technology governance, user engagement, and product optimization.

Typhoons trigger complex chains of secondary disasters. Therefore, accurately quantifying their total intensity is crucial for effective prediction. However, conventional methods typically rely on single parameters, such as maximum wind speed or minimum central pressure, which fail to capture a typhoon’s full destructive potential. Integrating these disparate physical quantities into prediction models remains a challenge. To address this limitation, we propose a unified metric: the Integrated Tropical Cyclone Strength (ITCS). This method combines wind speed and air pressure into one single number. And the process has three simple steps. Firstly, we standardized the variables based on their physical properties. Secondly, we combined them using weights. We gave wind speed a weight of 0.7 and air pressure a weight of 0.3. We chose these numbers based on energy analysis. Thirdly, we broke the index into levels. This makes it easy to use with Markov models. We tested the ITCS with historical typhoon data. The index successfully showed how real typhoons change over time. We also did a test using Typhoon Bualoi. The model achieved an RMSE of 4.76 and an MAE of 3.82. This proves our index is strong and easy to learn. The ITCS gives us a new way to model complex typhoon disaster chains. And it improves the accuracy of typhoon forecasting. The ITCS gives us a new framework for modeling typhoon disaster chains. It helps us predict these complex events intelligently. And it improves the accuracy of multi-hazard forecasting. It makes the science behind these predictions stronger. But this method is useful for more than just typhoons. It offers a general way to build indices from different data sources. So, it has value for other systems too. It can help assess other weather risks and environmental hazards.

A seismic analysis framework for the vehicle-bridge interaction (VBI) system, based on ABAQUS software, is proposed in this study. The primary focus is on the driving safety of curved bridges subjected to frequent seismic excitation. Three-dimensional dynamic models are developed for both the vehicle and the bridge. A penalty factor is introduced to control the relative displacement between the contact surfaces, simulating the interaction between the bridge deck and the vehicle wheels. Using the Dateng Gorge curved bridge as a case study, a direct solution method is employed to analyze the safety of driving on the bridge under earthquake excitation, using 10 measured ground motions. The results reveal that vehicles traveling at low speeds on the bridge during an earthquake are more likely to experience seismic effects, increasing the side-slip safety factor (SSF) and making vehicles more susceptible to side-slip. Seismic load characteristics, such as epicentral distance, significantly influence the SSF. Heavier vehicles tend to exhibit a lower SSF, indicating better stability under seismic forces. Pavement conditions also play a crucial role; snowy and wet pavements lead to higher SSF values and an increased risk of side-slip, while dry pavements provide optimal stability. This study highlights the importance of considering these factors when assessing vehicle safety and mitigating side-slip risks on seismic-prone bridges.

The chlorinated polyvinyl chloride (CPVC)/acrylonitrile–butadiene–styrene (ABS) composite represents an important class of engineering thermoplastics, offering a strong balance of flame retardancy, chemical resistance, mechanical properties, processability, and cost efficiency. Despite its widespread application, the flame-retardant mechanism in the CPVC/ABS system remains poorly understood. This work systematically investigated the non-monotonic flame-retardant behavior of CPVC/ABS composites through comprehensive characterization. The combustion performance, as determined by limiting oxygen index (LOI), UL-94 vertical burning tests, and cone calorimeter tests (CCTs), showed an unexpected pattern of flame retardancy initially improving then decreasing with reduced ABS content, which contradicted conventional expectations. The optimal composition at a CPVC/ABS ratio of 2:3 demonstrated good performance, achieving a UL-94 5VA rating and 47.3% reduction in total heat release (THR) relative to CPVC. A more stable and compact structure was observed from the morphology analysis of the residual char, and the thermogravimetric analysis further revealed a synergistic effect in carbonization behavior. The above flame-retardant mechanism could be interpreted by the combined effects of accelerated char formation during the early decomposition stage and significantly enhanced char crosslinking degree. These findings provided fundamental insights for designing high-performance flame-retardant polymer composites and facilitating their industrial implementation.

ABSTRACTThis work is meant to study the effect of galacto‐oligosaccharide (GOS) intervention in the fecal microbiota of obese mice on lipid metabolism and anti‐obesity in mice. A pseudo‐germ‐free mice model was established by administration of a mixture of antibiotics. The fecal microbiota of GOS‐fed obese mice are transplanted into pseudo‐germ‐free mice. To investigate the effects of GOS intervention on lipid metabolism, lipid quadruple, bile acid metabolism, and intestinal microbiota in obese mice. At the same time, the expression of BAS synthase and the effects of FXR‐SHP and FXR‐FGF15‐FGFR4 signaling pathways on BAS homeostasis were also explored. The fecal microbiota of obese mice intervened by GOS could reshape the structure of intestinal microbiota, regulate the synthesis of bile acids in the enterohepatic circulation and the expression of transport‐related factors, and promote metabolic ability to exert anti‐obesity effects.