截至2025年8月26日收盘，正海生物股价报22.23元，较前一交易日下跌0.22元，跌幅0.98%。当日成交 量为33418手，成交额0.75亿元，换手率1.86%。 正海生物属于医疗器械板块，主营业务为生物再生材料的研发、生产与销售，产品涵盖口腔修复膜、生 物膜等医用材料。 风险提示：市场有风险，投资需谨慎。 公司8月26日在互动平台表示，其钙硅生物陶瓷骨修复材料属于非动物源人工合成骨修复材料，未来上 市后将按13%税率征收增值税。同时，公司明确表示暂无开发非动物源性脑膜系列产品的计划。此外， 正海生物将于8月27日召开临时股东大会，审议变更经营范围、修订公司章程等多项议案。 资金方面，8月26日主力资金净流出242.05万元，近五日累计净流出2199.57万元。 ...

Core Insights - A new study from MIT reveals that bacterial biofilms play a crucial role in determining the accumulation of microplastics in riverbeds, making them more susceptible to being washed away by water flow [1][2] - The presence of biofilms reduces the space available for microplastics to embed within sand particles, thus increasing their exposure to water flow and facilitating their removal [2] Group 1 - Microplastics are increasingly concerning due to their accumulation in the environment and human bodies, complicating pollution management efforts [1] - The study published in "Geophysical Research Letters" highlights that biofilms are key factors influencing microplastic distribution and sedimentation [1] - The research utilized a flume experiment to simulate conditions affecting microplastic behavior, demonstrating the impact of biofilms on microplastic accumulation [1][2] Group 2 - The study identified two phenomena affecting microplastic accumulation: turbulence around simulated root systems hinders sedimentation, while increased biofilm content reduces microplastic accumulation [2] - Biofilms fill the gaps between sand particles, making it difficult for microplastics to embed and thus more likely to be carried away by water flow [2] - The researchers suggest that monitoring efforts should focus on sandy outer regions of mangrove ecosystems, where microplastics are likely to accumulate due to lower biofilm presence [2]