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Jan 2025, Volume 44 Issue 1
    
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    Editorial
  • Zhou Ji, Raj Reddy
  • Views & Comments
  • Bo Song, Shaoji Zhang, Lei Zhang, Yusheng Shi
  • Views & Comments
  • Kinam Kim
  • Wei Xiang, Lu Yu, Xiaoyuan Chen, Marco J. Herold
  • Zhenhua Rui, Lianbo Zeng, Birol Dindoruk
  • Views & Comments
  • Ziyou Gao, Bin Jia, Dongfan Xie, Wenxu Wang, Jianjun Wu
  • Views & Comments
  • Mirosław J. Skibniewski
  • Research
  • Perspective
    Li-Jun Hu, Zhi-Zhang Duan, Ying Wang, Wen-Cai Ye, Chun-Tao Che

    Natural products, with their remarkable structural and biological diversity, have historically served as a vital bridge between chemistry, the life sciences, and medicine. They not only provide essential scaffolds for drug discovery but also inspire innovative strategies in drug development. The biomimetic synthesis of natural products employs principles from biomimicry, applying inspiration from biogenetic processes to design synthetic strategies that mimic biosynthetic processes. Biomimetic synthesis is a highly efficient approach in synthetic chemistry, as it addresses critical challenges in the synthesis of structurally complex natural products with significant biological and medicinal importance. It has gained widespread attention from researchers in chemistry, biology, pharmacy, and related fields, underscoring its interdisciplinary impact. In this perspective, we present recent advances and challenges in the biomimetic synthesis of natural products, along with the significance and prospects of this field, highlighting the transformative potential of biomimetic synthesis strategies for both chemical and biosynthetic approaches to natural product synthesis in the pursuit of novel therapeutic agents.

  • Perspective
    Zhiguo Wang, Baofeng Yang
    Despite recent advances in understanding the biology of aging, the field remains fragmented due to the lack of a central organizing hypothesis. Although there are ongoing debates on whether the aging process is programmed or stochastic, it is now evident that neither perspective alone can fully explain the complexity of aging. Here, we propose the pro-aging metabolic reprogramming (PAMRP) theory, which integrates and unifies the genetic-program and stochastic hypotheses. This theory posits that aging is driven by degenerative metabolic reprogramming (MRP) over time, requiring the emergence of pro-aging substrates and triggers (PASs and PATs) to predispose cells to cellular and genetic reprogramming (CRP and GRP).
  • Perspective
    Min Ouyang, Zekai Cheng, Jiaxin Ma, Hongwei Wang, Stergios Aristoteles Mitoulis
    The complexity of coupled risks, which refer to the compounded effects of interacting uncertainties across multiple interdependent objectives, is inherent to cities functioning as dynamic, interdependent systems. A disruption in one domain ripples across various urban systems, often with unforeseen consequences. Central to this complexity are people, whose behaviors, needs, and vulnerabilities shape risk evolution and response effectiveness. Realizing cities as complex systems centered on human needs and behaviors is essential to understanding the complexities of coupled urban risks. This paper adopts a complex systems perspective to examine the intricacies of coupled urban risks, emphasizing the critical role of human decisions and behavior in shaping these dynamics. We focus on two key dimensions: cascading hazards in urban environments and cascading failures across interdependent exposed systems in cities. Existing risk assessment models often fail to capture the complexity of these processes, particularly when factoring in human decision-making. To tackle these challenges, we advocate for a standardized taxonomy of cascading hazards, urban components, and their interactions. At its core is a people-centric perspective, emphasizing the bidirectional interactions between people and the systems that serve them. Building on this foundation, we argue the need for an integrated, people-centric risk assessment framework that evaluates event impacts in relation to the hierarchical needs of people and incorporates their preparedness and response capacities. By leveraging real-time data, advanced simulations, and innovative validation methods, this framework aims to enhance the accuracy of coupled urban risk modeling. To effectively manage coupled urban risks, cities can draw from proven strategies in real complex systems. However, given the escalating uncertainties and complexities associated with climate change, prioritizing people-centric strategies is crucial. This approach will empower cities to build resilience not only against known hazards but also against evolving and unforeseen challenges in an increasingly uncertain world.
  • Review
    Chuanyu Zhang,Philippe Brunet,Shuo Liu,Xiaofeng Guo,Laurent Royon,Xianming Qin,Xueyong Wei
    Acoustofluidics is a term describing the class of phenomena in which mechanical or acoustic vibrations induce a deformation or a flow in a fluid. Many deficiencies in our understanding of these phenomena remain to be addressed, with respect to the fundamental theoretical framework as well as in numerous applications. In this regard, the frequency of external forcing is a key parameter. Owing to the low cost, substantial magnitude, and versatility associated with acoustofluidic phenomena at audible frequencies, studies of these phenomena in the audible range have emerged with increasing amount in recent years and have attracted considerable attention. However, compared with studies focusing on the ultrasonic frequency domain, critical features and information specific to audible acoustofluidics remain dispersed across many independent publications, and a systematic integration of the literature on this topic is necessary. Accordingly, this review summarizes the basic theory and methods for generating vibrations in the audible range, presents various applications thereof in biology, chemistry, and other fields, and provides a high-level overview of the current status of the topic to motivate developing interesting proposals for further research in this field of study.
  • Review
    Xinxia Cai, Zhaojie Xu, Jingquan Liu, Robert Wang, Yirong Wu

    Intracortical neural interfaces directly connect brain neurons with external devices to achieve high temporal resolution and spatially precise sampling of neural activity. When applied to freely moving animals, this technology provides in-depth insight into the underlying neural mechanisms for their movement and cognition in real-world scenarios. However, the application of implanted devices in freely moving animals is limited by restrictions on their behavioral freedom and physiologic impact. In this paper, four technological directions for ideal implantable neural interface devices are analyzed: higher spatial density, improved biocompatibility, enhanced multimodal detection of electrical/neurotransmitter signals, and more effective neural modulation. Finally, we discuss how these technological developments have been applied to freely moving animals to provide better insight into neuroscience and clinical medicine.

  • Review
    Fei Wu, Tao Shen, Thomas Bäck, Jingyuan Chen, Gang Huang, Yaochu Jin, Kun Kuang, Mengze Li, Cewu Lu, Jiaxu Miao, Yongwei Wang, Ying Wei, Fan Wu, Junchi Yan, Hongxia Yang, Yi Yang, Shengyu Zhang, Zhou Zhao, Yueting Zhuang, Yunhe Pan

    Large language models (LLMs) have significantly advanced artificial intelligence (AI) by excelling in tasks such as understanding, generation, and reasoning across multiple modalities. Despite these achievements, LLMs have inherent limitations including outdated information, hallucinations, inefficiency, lack of interpretability, and challenges in domain-specific accuracy. To address these issues, this survey explores three promising directions in the post-LLM era: knowledge empowerment, model collaboration, and model co-evolution. First, we examine methods of integrating external knowledge into LLMs to enhance factual accuracy, reasoning capabilities, and interpretability, including incorporating knowledge into training objectives, instruction tuning, retrieval-augmented inference, and knowledge prompting. Second, we discuss model collaboration strategies that leverage the complementary strengths of LLMs and smaller models to improve efficiency and domain-specific performance through techniques such as model merging, functional model collaboration, and knowledge injection. Third, we delve into model co-evolution, in which multiple models collaboratively evolve by sharing knowledge, parameters, and learning strategies to adapt to dynamic environments and tasks, thereby enhancing their adaptability and continual learning. We illustrate how the integration of these techniques advances AI capabilities in science, engineering, and society—particularly in hypothesis development, problem formulation, problem-solving, and interpretability across various domains. We conclude by outlining future pathways for further advancement and applications.

  • Review
    Zan Li, Jia Shi, Jiangbo Si, Lu Lv, Lei Guan, Benjian Hao, Zhuangzhuang Tie, Danyang Wang, Chengwen Xing, Tony Q.S. Quek

    With the future substantial increase in coverage and network heterogeneity, emerging networks will encounter unprecedented security threats. Covert communication is considered a potential enhanced security and privacy solution for safeguarding future wireless networks, as it can enable monitors to detect the transmitter’s transmission behavior with a low probability, thereby ensuring the secure transmission of private information. Due to its favorable security, it is foreseeable that covert communication will be widely used in various wireless communication settings such as medical, financial, and military scenarios. However, existing covert communication methods still present many challenges toward practical applications. In particular, it is difficult to guarantee the effectiveness of covert schemes based on the randomness of eavesdropping environments, and it is challenging for legitimate users to detect weak covert signals. Considering that emerging artificial-intelligence-aided transmission technologies can open up entirely new opportunities to address the above challenges, we provide a comprehensive review of recent advances and potential research directions in the field of intelligent covert communications in this work. First, the basic concepts and performance metrics of covert communications are introduced. Then, existing effective covert communication techniques in the time, frequency, spatial, power, and modulation domains are reviewed. Finally, this paper discusses potential implementations and challenges for intelligent covert communications in future networks.

  • Review
    Xinmeng Liu, Zhiquan Shu, Liming Zhang, Haoyue Li, Jing Yang, Lei Zhang
    Recent advances in organ transplantation, regenerative medicine, and drug discovery have emphasized the critical importance of effective preservation techniques for organs. Despite these advances, current preservation techniques have significant limitations in maintaining the viability and functional efficacy of organs over the long term. As a result, there is a pressing need to develop reliable and efficient preservation strategies for organs. Currently, the clinical standard for organ preservation involves the use of static cold storage and organ machine perfusion, but these methods can only preserve organs for a couple of days or even a few hours. Notably, the development of cryobiology has yielded promising alternatives. In this review, we aim to provide a comprehensive overview of the progression of organ preservation methods, while emphasizing the limitations of traditional approaches. Moreover, we evaluate advanced preservation techniques for organs, including kidneys, livers, hearts, lungs, and intestines. Furthermore, we share a progress perspective on the future of organ preservation, with the ultimate goal of achieving viable long-term preservation to address the pressing issue of organ shortage.
  • Review
    Chao Yang, Guang-Wen Chu, Xin Feng, Yan-Bin Li, Jie Chen, Dan Wang, Xiaoxia Duan, Jian-Feng Chen
    The mixing process plays a pivotal role in the design, optimization, and scale-up of chemical reactors. For most chemical reactions, achieving uniform and rapid contact between reactants at the molecular level is crucial. Mixing intensification encompasses innovative methods and tools that address the limitations of inadequate mixing within reactors, enabling efficient reaction scaling and boosting the productivity of industrial processes. This review provides a concise introduction to the fundamentals of multiphase mixing, followed by case studies highlighting the application of mixing intensification in the production of energy-storage materials, advanced optical materials, and nanopesticides. These examples illustrate the significance of theoretical analysis in informing and advancing engineering practices within the chemical industry. We also explore the challenges and opportunities in this field, offering insights based on our current understanding.
  • Review
    Jingbo Sun, Ji Zhou

    Composed of natural materials but constructed using artificial structures through ingenious design, metamaterials possess properties beyond nature. Unlike traditional materials studies, metamaterials research requires great human creativity in order to realize the desired properties and thereby the required functionalities through design. Such properties and functionalities are not necessarily available in nature, and their design can break through the existing materials ideology. This paper reviews progress in metamaterials research over the past 20 years in terms of the materials innovations that have achieved the designation of “meta.” In particular, we discuss future trends in metamaterials in the fields of both fundamental science and engineering.

  • Review
    Yong Zhao, Yanliang Du, Qixiang Yan
    With the implementation of significant national strategies and rapid socioeconomic development, many ultra-long deep tunnels are being constructed in the Qinghai–Xizang Plateau region. However, the extreme complexity and variability of the environment in this region pose significant challenges to the safe construction and long-term operation of the planned or under-construction ultra-long deep tunnels. To address these complex technical challenges, this paper provides a detailed analysis of the complex climate and geology features of the Qinghai–Xizang Plateau during tunnel construction. The climate characteristics of the Qinghai–Xizang Plateau include severe coldness, low oxygen, and unpredictable weather changes. The geological characteristics include complex stress distributions caused by the intense internal and external dynamic coupling of tectonic plates, widespread active tectonic structures, frequent high-intensity earthquakes, fractured rock masses, and numerous active fault zones. Based on the analysis, this paper elaborates on potential sources of major disasters resulting from the characteristics of ultra-long deep tunnel projects in the Qinghai–Xizang Plateau region. These potential disaster sources include the crossing of active fault zones, high geostress rockbursts, large deformation disasters, high-pressure water surges, geothermal hazards, inadequate long-distance ventilation and oxygen supply, and multi-hazard couplings. In response to these challenges, this paper systematically summarizes the latest research progress and technological achievements in the domestic and international literature, and proposes innovative ideas and future development prospects for disaster monitoring and early warning, mechanized intelligent construction, long-term safety services, and emergency security and rescue. These innovative measures are intended to address the challenges of tunnel disaster prevention and control in the complex environment of the Qinghai–Xizang Plateau, contributing to the safe construction and long-term operation of ultra-long deep tunnels in this region.
  • Review
    Yu Yan, Lei Ni, Lijun Sun, Ying Wang, Jianing Zhou
    Road infrastructure is facing significant digitalization challenges within the context of new infrastructure construction in China and worldwide. Among the advanced digital technologies, digital twin (DT) has gained prominence across various engineering sectors, including the manufacturing and construction industries. Specifically, road engineering has demonstrated a growing interest in DT and has achieved promising results in DT-related applications over the past several years. This paper systematically introduces the development of DT and examines its current state in road engineering by reviewing research articles on DT-enabling technologies, such as model creation, condition sensing, data processing, and interaction, as well as its applications throughout the lifecycle of road infrastructure. The findings indicate that research has primarily focused on data perception and virtual model creation, while real-time data processing and interaction between physical and virtual models remain underexplored. DT in road engineering has been predominantly applied during the operation and maintenance phases, with limited attention given to the construction and demolition phases. Future efforts should focus on establishing uniform standards, developing innovative perception and data interaction techniques, optimizing development costs, and expanding the scope of lifecycle applications to facilitate the digital transformation of road engineering. This research provides a comprehensive overview of state-of-the-art advancements in this field and paves the way for leveraging DT in road infrastructure lifecycle management.
  • Review
    Xiaoye Zhang, Junting Zhong, Xiliang Zhang, Da Zhang, Changhong Miao, Deying Wang, Lifeng Guo

    This paper proposes that China, under the challenge of balancing its development and security, can aim for the Paris Agreement’s goal to limit global warming to no more than 2 °C by actively seeking carbon-peak and carbon-neutrality pathways that align with China’s national conditions, rather than following the idealized path toward the 1.5 °C target by initially relying on extensive negative-emission technologies such as direct air carbon capture and storage (DACCS). This work suggests that pursuing a 1.5 °C target is increasingly less feasible for China, as it would potentially incur 3-4 times the cost of pursuing the 2 °C target. With China being likely to achieve a peak in its emissions around 2028, at about 12.8 billion tonnes of anthropogenic CO2, and become carbon neutral, projected global warming levels may be less severe after the 2050s than previously estimated. This could reduce the risk potential of climate tipping points and extreme events, especially considering that the other two major carbon emitters in the world (Europe and North America) have already passed their carbon peaks. While natural carbon sinks will contribute to China’s carbon neutrality efforts, they are not expected to be decisive in the transition stages. This research also addresses the growing focus on climate overshoot, tipping points, extreme events, loss and damage, and methane reductions in international climate cooperation, emphasizing the need to balance these issues with China’s development, security, and fairness considerations. China’s pursuit of carbon neutrality will have significant implications for global emissions scenarios, warming levels, and extreme event projections, as well as for climate change hotspots of international concern, such as climate tipping points, the climate crisis, and the notion that the world has moved from a warming to a boiling era. Possible research recommendations for global emissions scenarios based on China’s 2 °C target pathway are also summarized.

  • Review
    Chaopeng Hong, Rui Zhong, Mengyao Xu, Peidong He, Huibin Mo, Yue Qin, Danna Shi, Xinlei Chen, Kebin He, Qiang Zhang
    Food systems are deeply affected by climate change and air pollution, while being key contributors to these environmental challenges. Understanding the complex interactions among food systems, climate change, and air pollution is crucial for mitigating climate change, improving air quality, and promoting the sustainable development of food systems. However, the literature lacks a comprehensive review of these interactions, particularly in the current phase of rapid development in the field. To address this gap, this study systematically reviews recent research on the impacts of climate change and air pollution on food systems, as well as the greenhouse gas and air pollutant emissions from agri-food systems and their contribution to global climate change and air pollution. In addition, this study summarizes various strategies for mitigation and adaptation, including adjustments in agricultural practices and food supply chains. Profound changes in food systems are urgently needed to enhance adaptability and reduce emissions. This review offers a critical overview of current research on the interactions among food systems, climate change, and air pollution and highlights future research directions to support the transition to sustainable food systems.
  • Review
    Felix D. Dakora, Huihui Li, Jun Zhao
    Despite its negative impacts on plant functioning, climate change benefits plants at the cellular level. For example, the stimulation of C3 photosynthesis by elevated CO2 can increase N2 fixation by 73% and grain yield by 10%–11%. The global elevated atmospheric CO2 concentration has already decreased the nitrogen content in C3 crop species and C3 woody vegetation by 14% and 21%, respectively, regardless of added nitrogen fertilizer. 15N-feeding experiments have shown that, after 19 h under elevated CO2, the 15N concentration in the stems, roots plus rhizomes, and whole plants of Scirpus olneyi (S. olneyi) decreased by 51%, 63%, and 74%, respectively. Moreover, S. olneyi showed reduced NH4+ assimilation under elevated CO2, which decreased the amino acid contents in the stems by 25.6% for glycine and 65.0% for serine, and that in the roots plus rhizomes by 2% for gamma-aminobutyric acid (GABA) and 80% for glutamate. Wheat grain protein has also been found to decrease by 7.4% under elevated CO2 due to reductions in threonine, valine, iso-leucine, leucine, and phenylalanine. The mineral nutrient contents in grains of rice and maize were similarly found to decrease under high CO2 by 1.0% and 7.1% for phosphorus, 7.8% and 2.1% for sulfur, 5.2% and 5.8% for iron, 3.3% and 5.2% for zinc, 10.6% and 9.9% for copper, and 7.5% and 4.2% for manganese, respectively. In general, mineral concentrations in C3 plants are predicted to decrease by 8% under elevated CO2, while total non-structural carbohydrates (mainly starch and sugars) are expected to increase. These decreases in grain protein, amino acids, and mineral nutrients could double the incidence of global protein-calorie malnutrition and micronutrient deficiency—especially in Africa, where agricultural soils are inherently low in nutrient elements. Additionally, the increase in total non-structural carbohydrates (mainly starch and sugars) in cereal crops could elevate diabetes incidence due to heavy reliance on starchy diets. The negative effects of elevated CO2 on rice, maize, and wheat—the world's three major staple crops—suggest an increase in global food insecurity with rising atmospheric CO2 concentration.
  • Review
    Ying Zhang, Guanmin Huang, Yanxin Zhao, Xianju Lu, Yanru Wang, Chuanyu Wang, Xinyu Guo, Chunjiang Zhao

    The security of the seed industry is crucial for ensuring national food security. Currently, developed countries in Europe and America, along with international seed industry giants, have entered the breeding 4.0 era. This era integrates biotechnology, artificial intelligence (AI), and big data information technology. In contrast, China is still in a transition period between stages 2.0 and 3.0, which primarily relies on conventional selection and molecular breeding. In the context of increasingly complex international situations, accurately identifying core issues in China’s seed industry innovation and seizing the frontier of international seed technology are strategically important. These efforts are essential for ensuring food security and revitalizing the seed industry. This paper systematically analyzes the characteristics of crop breeding data from artificial selection to intelligent design breeding. It explores the applications and development trends of AI and big data in modern crop breeding from several key perspectives. These include high-throughput phenotype acquisition and analysis, multiomics big data database and management system construction, AI-based multiomics integrated analysis, and the development of intelligent breeding software tools based on biological big data and AI technology. Based on an in-depth analysis of the current status and challenges of China’s seed industry technology development, we propose strategic goals and key tasks for China’s new generation of AI and big data-driven intelligent design breeding. These suggestions aim to accelerate the development of an intelligent-driven crop breeding engineering system that features large-scale gene mining, efficient gene manipulation, engineered variety design, and systematized biobreeding. This study provides a theoretical basis and practical guidance for the development of China’s seed industry technology.

  • Review
    Alexander K. Zinsmaier, Eric J. Nestler, Yan Dong
    Understanding the cellular mechanisms of drug addiction remains a key task in current brain research. While neuron-based mechanisms have been extensively explored over the past three decades, recent evidence indicates a critical involvement of astrocytes, the main type of non-neuronal cell in the brain. In response to extracellular stimuli, astrocytes modulate the activity of neurons, synaptic transmission, and neural network properties, collectively influencing brain function. G protein-coupled receptors (GPCRs) expressed on astrocyte surfaces respond to neuron- and environment-derived ligands by activating or inhibiting astrocytic signaling, which in turn regulates adjacent neurons and their circuitry. In this review, we focus on the dopamine D1 receptors (D1R) and metabotropic glutamate receptor 5 (mGLUR5 or GRM5)—two GPCRs that have been critically implicated in the acquisition and maintenance of addiction-related behaviors. Positioned as an introductory-level review, this article briefly discusses astrocyte biology, outlines earlier discoveries about the role of astrocytes in substance-use disorders (SUDs), and provides detailed discussions of the roles of astrocytic D1Rs and mGLUR5s in regulating synapse and network functions in the nucleus accumbens (NAc)—a brain region that mediates addiction-related emotional and motivational behavioral responses. This review serves as a stepping stone for readers of Engineering to explore links between astrocytic GPCRs and drug addiction and other psychiatric disorders.