从电子垃圾到生态恢复:全球视角下的电子垃圾不平等处理模式与景观干预方法研究

电子技术的飞速发展导致了每年大量电子垃圾(废弃电气和电子设备)的产生,在发达国家尤其如此。在经济全球化的背景下,发展中国家和欠发达国家由于缺乏相关环境法律和政策的保护且劳动力成本较低,导致发达国家将数量庞大的电子垃圾出口至这些国家。在低技拆解这些电子垃圾的过程中,产生的有害化学物质进入空气、土壤和深层地下水,污染饮用水和食物,并最终进入人体。由于经济和政策发展不均衡,产生电子垃圾最少的国家和地区(例如中国、印度、加纳等)反而遭受最大的损失。本文研究了全球范围内电子垃圾的生产、分布和流动情况,及其不平等的分布和处理模式;随后分析了不同国家和国际电子垃圾回收政策,并讨论了非正规拆解行为对经济、社会和环境造成的影响;最后,以中国贵屿为例,重点关注农田、河流和城市用地三种用地类型,从关键景观问题中总结出景观干预策略和方法,并将其实施划分为三个不同的恢复和发展阶段。本文旨在从景观干预的角度,为全球电子垃圾污染地区的生态、健康和生计恢复提供研究和干预建议。

Chinese herb pollen derived micromotors as active oral drug delivery system for gastric ulcer treatment

Considerable efforts have been devoted to treating gastric ulcers.Attempts in this field tend to develop drug delivery systems with prolonged gastric retention time.Herein,we develop novel Chinese herb pollen-derived micromotors as active oral drug delivery system for treating gastric ulcer.Such Chinese herb pollen-derived micromotors are simply produced by asymmetrically sputtering Mg layer onto one side of pollen grains.When exposed to gastric juice,the Mg layer can react with the hydrogen ions,resulting in intensive generation of hydrogen bubbles to propel the micromotors.Benefiting from the autonomous motion and unique spiny structure,our micromotors can move actively in the stomach and adhere to the surrounding tissues.Besides,their special architecture endows the micromotors with salient capacity of drug loading and releasing.Based on these features,we have demonstrated that our Chinese herb pollen-derived micromotors could effective deliver berberine hydrochloride and show desirable curative effect on the gastric ulcer model of mice.Therefore,these Chinese herb pollen-derived micromotors are anticipated to serve as promising oral drug delivery carriers for clinical applications.

Biomimetic Gland Models with Engineered Stratagems

As extensively distributed tissues throughout the human body,glands play a critical role in various physiological processes.Therefore,the construction of biomimetic gland models in vitro has aroused great interest in multiple disciplines.In the biological field,the researchers focus on optimizing the cell sources and culture techniques to reconstruct the specific structures and functions of glands,such as the emergence of organoid technology.From the perspective of biomedical engineering,the generation of biomimetic gland models depends on the combination of engineered scaffolds and microfluidics,to mimic the in vivo environment of glandular tissues.These engineered stratagems endowed gland models with more biomimetic features,as well as a wide range of application prospects.In this review,we first describe the biomimetic strategies for constructing different in vitro gland models,focusing on the role of microfluidics in promoting the structure and function development of biomimetic glands.After summarizing several common in vitro models of endocrine and exocrine glands,the applications of gland models in disease modelling,drug screening,regenerative medicine,and personalized medicine are enumerated.Finally,we conclude the current challenges and our perspective of these biomimetic gland models.

Inhibition of the maize salt overly sensitive pathway by ZmSK3 and ZmSK4

Soil salinity is a worldwide problem that adversely affects plant growth and crop productivity. The salt overly sensitive (SOS) pathway is evolutionarily conserved and essential for plant salt tolerance. In this study, we reveal how the maize shaggy/glycogen synthase kinase 3-like kinases ZmSK3 and ZmSK4, orthologs of brassinosteroid insensitive 2 in Arabidopsis thaliana, regulate the maize SOS pathway. ZmSK3 and ZmSK4 interact with and phosphorylate ZmSOS2, a core member of the maize SOS pathway. The mutants defective in ZmSK3 or ZmSK4 are hyposensitive to salt stress, with higher salt-induced activity of ZmSOS2 than that in the wild type. Furthermore, the Ca^(2+) sensors ZmSOS3 and ZmSOS3-like calcium binding protein 8 (ZmSCaBP8) activate ZmSOS2 to maintain Na^(+)/K^(+) homeostasis under salt stress and may participate in the regulation of ZmSOS2 by ZmSK3 and ZmSK4. These findings discover the regulation of the maize SOS pathway and provide important gene targets for breeding salt-tolerant maize.

Bee Sting-Inspired Inflammation-Responsive Microneedles for Periodontal Disease Treatment

Periodontal lesions are common and frustrating diseases that impact life quality.Efforts in this aspect aim at developing local drug delivery systems with better efficacy and less toxicity.Herein,inspired by the sting separation behavior of bees,we conduct novel reactive oxygen species(ROS)-responsive detachable microneedles(MNs)that carry antibiotic metronidazole(Met)for controllable periodontal drug delivery and periodontitis treatment.Benefiting from the needle-base separation ability,such MNs can penetrate through the healthy gingival to reach the gingival sulcus's bottom while offering minimal impact to oral function.Besides,as the drug-encapsulated cores were protected by poly(lactic-co-glycolic acid)(PLGA)shells in MNs,the surrounding normal gingival tissue is not affected by Met,resulting in excellent local biosafety.Additionally,with the ROS-responsive PLGA-thioketal-polyethylene glycol MN tips,they can be unlocked to release Met directly around the pathogen under the high ROS in the periodontitis sulcus,bringing about improved therapeutic effects.Based on these characteristics,the proposed bioinspired MNs show good therapeutic results in treating a rat model with periodontitis,implying their potential in periodontal disease.

Developing hierarchical microneedles for biomedical applications

As a new kind of microcarrier device,microneedles are featured by micrometer needle arrays with an overall size in the centimeter scale.Due to the needle shape and the micron size,microneedles can penetrate the skin without harming nerves and blood vessels,which causes many advantages such as minimally invasive,safe and convenient.The past few decades have witnessed a great leap in microneedles research.The main materials of microneedles have changed from metal and ceramic to polymers with more complex functions,and the optimiza-tion of materials and preparation strategies has led to a greater variety of microneedle styles.Among them,the construction or combination of smaller size structures or materials on microneedles to fabricate hierarchical mi-croneedles is a major research hotspot.Here,we present the recent research progress of hierarchical microneedles for biomedicine.We begin by discussing the fabrication strategies of hierarchical microneedles,including main-stream casting and coating methods based on microneedle molds and three dimensions(3D)printing methods.We then expand the discussion from the hierarchical microneedles with porous structure to those composited with nanomaterials.Eventually,we have a discussion about the research progress of hierarchical microneedles in the area of biomarkers detection and transdermal drug delivery,as well as its future development direction.