Despite rapid advances in urban transit electrification, the progress of systematic planning and management of the electric bus (EB) fleet is falling behind. In this research, the fundamental issues affecting the nascent EB system are first reviewed, including charging station deployment, battery sizing, bus scheduling, and life-cycle analysis. At present, EB systems are planned and operated in a sequential manner, with bus scheduling occurring after the bus fleet and infrastructure have been deployed, resulting in low resource utilization or waste. We propose a mixed-integer programming model to consolidate charging station deployment and bus fleet management with the lowest possible life-cycle costs (LCCs), consisting of ownership, operation, maintenance, and emissions expenses, thereby narrowing the gap between optimal
planning and operations. A tailored branch-and-price approach is further introduced to reduce the computational effort required for finding optimal solutions. Analytical results of a real-world case show that, compared with the current bus operational strategies and charging station layout, the LCC of one bus line can be decreased significantly by 30.4%. The proposed research not only performs life-cycle analysis but also provides transport authorities and operators with reliable charger deployment and bus schedules for single- and multi-line services, both of which are critical requirements for decision support in future transit systems with high electrification penetration, helping to accelerate the transition to sustainable mobility.
This paper presents the development of a novel micro force sensor based on a laterally movable gate field-effect transistor (LMGFET). A precise electrical model is proposed for the performance evaluation of small-scale LMGFET devices and exhibits improved accuracy in comparison with previous models. A novel sandwich structure consisting of a gold cross-axis decoupling gate array layer and two soft photoresistive SU-8 layers is utilized. With the proposed dual-differential sensing configuration, the output current of the LMGFET lateral operation under vertical interference is largely eliminated, and the relative output error of the proposed sensor decreases from 4.53% (traditional differential configuration) to 0.01%. A practicable fabrication process is also developed and simulated for the proposed sensor. The proposed LMGFET-based force sensor exhibits a sensitivity of 4.65 µA·nN−1, which is comparable with vertically movable gate field-effect transistor (VMGFET) devices, but has an improved nonlinearity of 0.78% and a larger measurement range of ±5.10 µN. These analyses provide a comprehensive design optimization of the electrical and structural parameters of LMGFET devices and demonstrate the proposed sensor's excellent force-sensing potential for biomedical micromanipulation applications.
Due to its limited intelligence and abilities, machine learning is currently unable to handle various situations thus cannot completely replace humans in real-world applications. Because humans exhibit robustness and adaptability in complex scenarios, it is crucial to introduce humans into the training loop of artificial intelligence (AI), leveraging human intelligence to further advance machine learning algorithms. In this study, a real-time human-guidance-based (Hug)-deep reinforcement learning (DRL) method is developed for policy training in an end-to-end autonomous driving case. With our newly designed mechanism for control transfer between humans and automation, humans are able to intervene and correct the agent's unreasonable actions in real time when necessary during the model training process. Based on this human-in-the-loop guidance mechanism, an improved actor-critic architecture with modified policy and value networks is developed. The fast convergence of the proposed Hug-DRL allows real-time human guidance actions to be fused into the agent's training loop, further improving the efficiency and performance of DRL. The developed method is validated by human-in-the-loop experiments with 40 subjects and compared with other state-of-the-art learning approaches. The results suggest that the proposed method can effectively enhance the training efficiency and performance of the DRL algorithm under human guidance without imposing specific requirements on participants' expertise or experience.
In this work, the nucleobase unit of the antiviral drug remdesivir, 7-bromopyrrolo[2,1-f][1,2,4]triazin-4-amine, was synthesized through five-step continuous flow. By adapting batch synthetic chemistry, 7-bromopyrrolo[2,1-f][1,2,4]triazin-4-amine was successfully produced through sequential flow operations from the widely available and inexpensive starting material pyrrole. Under optimal flow conditions, 7-bromopyrrolo[2,1-f][1,2,4]triazin-4-amine was obtained in 14.1% isolated yield in a total residence time of 79 min with a throughput of 2.96 g·h−1. The total residence time was significantly shorter than the total time consumed in batch procedures (> 26.5 h). In flow, the highly exothermic Vilsmeier–Haack and N-amination reactions involving hazardous and unstable intermediates, oxidative liquid–liquid biphasic transformation, and a bromination reaction requiring strict cryogenic conditions are favorably facilitated. The salient feature of this synthesis is that the workup procedures are fully integrated into the reaction sequences by deploying dedicated equipment and separation units, thus forming a streamlined continuous-flow system that maximizes the overall process efficiency. This method represents a greener and more sustainable process to prepare this nucleobase unit with high efficiency and safety.
The chemical industry is a major carbon emitter in China and must be focused on for China to achieve its goal of carbon neutralization. CO2 high-temperature electrolysis based on solid oxide electrolysis cells (SOECs) is an important technology to achieve China's carbon emission reduction, peak carbon emission, and carbon neutralization goals. Moreover, this technology can realize the recycling utilization of CO2 and thereby contribute to considerable environmental benefits and potential economic benefits. Thus far, a great deal of progress has been made in CO2 high-temperature electrolysis technology at the laboratory stage and pilot stage, although the large-scale industrial application of this technology still requires further development. This review focuses on recent progress in state-of-the-art cell materials for hightemperature CO2 electrolysis, discusses the future research directions of SOEC technologies, and proposes possible SOEC-coupled chemical industry carbon neutralization solutions.
China has made great efforts to fight environmental contamination along with rapid development and industrialization over the past few decades. However, the effects of these nationwide measures, such as energy restructuring, on pollutant residuals in soil have not been well quantified. Polycyclic aromatic hydrocarbon (PAH) pollution is a major concern around the world, and PAH emissions are associated with the energy structure. Therefore, we speculated that the adjustment of the energy structure in China may reduce the content of PAHs in soil. To test this hypothesis, we measured the concentrations of sixteen US Environmental Protection Agency (US EPA) priority PAH compounds (Σ16PAHs) at 54 soil sampling sites in Beijing in 2008 and 2019 and compiled nationwide data for 1704 soil sampling sites in the past two decades. The results showed that the Σ16PAH concentrations descended along the urban–suburban–rural–background gradient, and they first increased with increasing gross regional production (GRP) and plateaued when the GRP reached a certain level. The average Σ16PAH concentrations showed a decreasing trend across China over the past 20 years, and they decreased significantly from 22.7 μg·g−1 total organic carbon (TOC) in 2008 to 10.0 μg·g−1 TOC in 2019 in Beijing. The source identification analyses inferred that the decreasing trend of soil PAHs was due to the declines in the consumption of coal, coke, and some oils and the rising consumption of clean energy, such as electricity and natural gas, in China. This study demonstrates the important role of adjusting the energy structure in decreasing soil PAH concentrations and improving soil environmental quality.
Nano zero-valent iron biochar (nZVI–BC), an environmentally-friendly functional material prepared from waste biomass, has attracted extensive attention. This material has potential to solve the problem of biomass conversion. However, the lack of a method of converting biomass to the nZVI–BC involved in biomass modification and pyrolysis hinders its further production and application. In this study, we introduced the green solvent polyethylene glycol 400 (PEG400) to a biomass (rice straw, RS) modification system with FeCl3·6H2O, and activated RS was prepared to nZVI–BC by one-step pyrolysis. The addition of PEG400 promoted the hydrolysis of iron ion and improved the RS surface structure, promoting the attachment of Fe2O3 to the RS surface. The mild activation conditions with temperatures of 60, 80, 100 °C and a time of 0.5 h prevented the excessive loss of the lignin component and were conducive to the formation of carbon skeletons. Amorphous carbon and Fe2O3 were subjected to redox reactions to form nZVI–BC with the assistance of reducing gas produced from pyrolysis. In addition, the prepared nZVI–BC was tested for dye (Congo red) removal, showing rapid absorption (70.6% at 5 min) and high catalysis in advanced oxidation (75.67% at 5 min, 90% at 60 min). This work proposed a novel mechanistic strategy for preparing nZVI–BC and set a foundation for its scaled production and application.
Meeting the ever-growing demands of humans while ensuring sustainability is one of the great challenges of this century. China has made significant economic progress in recent decades and is increasingly engaged in international activities. This economic prosperity, however, has resulted in substantial contaminant discharge and damage to domestic aquatic ecosystems. Considerable efforts have been made to address these issues through developments in wastewater services infrastructure. Here, we provide an overview of wastewater infrastructure development in the Yangtze River Economic Zone during 2007–2017 and analyze diverse long-term monitoring data. These analyses trace and capture the key drivers affecting the restoration of water quality and determine how such restoration may be sustained or even accelerated in future. We find that there has been a decoupling trend between the economy and environmental variables since 2013, which coincides with the substantial implementation of improved wastewater treatment systems. While further developments in sewerage facilities and phosphorus discharge reduction may continue restoration, a paradigm shift toward a circular economy remains necessary to integrate these developments with wastewater resources management. Overall, this study advances the current understanding of the impact of wastewater services facilities on the balance between economic development and environmental protection.
A conductive ceramic composite (CCC) based on carbonized phenolic resin is fabricated via a facile and scalable dry-pressing method. A conductive carbonaceous precursor solution is homogeneously mixed with a ceramic precursor. Subsequently, carbonization and ceramicization are achieved simultaneously in a single heating process. The carbonized materials endow the composites with excellent electrical conductivity and reliable cyclic heating properties. The temperature of the obtained composites is approximately 386 °C at 12 V after 10 min and 400 °C at 20 V after 48 s, and their low energy consumption is low. Thermal images show that an even heat distribution is achieved on the composite surface, and that the electro–thermal performance can be adjusted by changing the electrical circuit arrangement (series or parallel circuits). In addition, the ceramic composites exhibit favorable electromagnetic interference shielding performance of 26.2 dB at 8.2 GHz and improved photothermal conversion effect compared with the pristine ceramic. More importantly, this single-step heating provides a convenient and cost-effective approach for producing CCCs, thereby enabling the scalable production of conductive ceramics for electro–thermal applications. The excellent electrical performance facilitates the application of ceramic composites in Joule heating (e.g., deicing, boiling water, and cooking) and electromagnetic interference shielding.
In the rapid development of modern materials, there is a great need for novel energy-saving, time-saving, cost-saving, and facile approaches to fabricate light, low-density, and high-porosity aerogels with excellent mechanical and thermal performance. In this work, a freeze-extraction method combined with normal vacuum drying (VD), using short electrospun polyimide (PI) fibers as a supporting skeleton, was developed to prepare high-performance PI fibrous aerogels (PIFAs) without the need for a special drying process. The resulting PIFAs exhibit low density (≤ 52.8 mg·cm–3) and high porosity (> 96%). The PIFAs are highly fatigue resistant, with cycling compression for at least 20 000 cycles and a low energy-loss coefficient. A thermal conductivity of 40.4 mW·m–1·K–1 was obtained for a PIFA with a density of 39.1 mg·cm–3. Further modification of the PIFAs with polysilazane led to enhanced fire resistance and a high residue (> 70%) in a nitrogen atmosphere. These excellent properties make PIFAs and their composites promising candidates for lightweight construction, thermal insulating, and fireproof layers for the construction industry, aviation, and aerospace industries, as well as for high-temperature reaction catalyst carriers. In addition, the proposed freezing-extraction/VD approach can be extended to other material systems to provide savings in energy, time, and costs.
Urban flooding is a major issue worldwide, causing huge economic losses and serious threats to public safety. One promising way to mitigate its impacts is to develop a real-time flood risk management system; however, building such a system is often challenging due to the lack of high spatiotemporal rainfall data. While some approaches (i.e., ground rainfall stations or radar and satellite techniques) are available to measure and/or predict rainfall intensity, it is difficult to obtain accurate rainfall data with a desirable spatiotemporal resolution using these methods. This paper proposes an image-based deep learning model to estimate urban rainfall intensity with high spatial and temporal resolution. More specifically, a convolutional neural network (CNN) model called the image-based rainfall CNN (irCNN) model is developed using rainfall images collected from existing dense sensors (i.e., smart phones or transportation cameras) and their corresponding measured rainfall intensity values. The trained irCNN model is subsequently employed to efficiently estimate rainfall intensity based on the sensors' rainfall images. Synthetic rainfall data and real rainfall images are respectively utilized to explore the irCNN's accuracy in theoretically and practically simulating rainfall intensity. The results show that the irCNN model provides rainfall estimates with a mean absolute percentage error ranging between 13.5% and 21.9%, which exceeds the performance of other state-of-the-art modeling techniques in the literature. More importantly, the main feature of the proposed irCNN is its low cost in efficiently acquiring high spatiotemporal urban rainfall data. The irCNN model provides a promising alternative for estimating urban rainfall intensity, which can greatly facilitate the development of urban flood risk management in a real-time manner.
Perfect surgical techniques and adequate immunosuppression are key to ensuring optimal graft and patient survival. The availability of different drugs has led to several, often industry-driven, heterogeneous clinical trials to discover an ideal immunosuppressive regimen. However, the considerable and conceptually diverse study designs have failed to afford a clear definition of the optimal immunosuppression regimen. The triple-drug immunosuppressive regimen, based on the calcineurin inhibitor tacrolimus, antimetabolites mofetil mycophenolate or azathioprine, and short-term steroids—beyond possible induction—remains the currently accepted standard immunosuppression in liver transplantation. However, this regimen needs to be challenged in light of the changing definitions of rejection, customization of the immunosuppressive load, and long-term side effects due to chronic immunosuppression. Future trials should preferably include more than a single endpoint rather than acute T-cell-mediated acute rejection (a-TCMR) or kidney failure. Conversely, a comprehensive endpoint that covers patient and graft survival rates and the incidence of both acute and chronic rejection is warranted. These immune phenomena should be examined in light of serial long-term biological and histological follow-up. The diagnosis and treatment of clinically relevant a-TCMR should be based on integrated biological, immunological, and histopathological findings. Both elements are critical to progress toward more prudent immunosuppression handling and favor clinical operational tolerance.
Osteosarcoma (OS) is a malignant mesenchymal tissue tumor known to occur in children and adolescents, and pulmonary metastasis often leads to death in these patients. The mechanism underlying OS progression remains unclear. Therefore, identifying new therapeutic targets and treatment modalities for OS is urgently needed. Abnormally expressed non-coding circular RNAs (circRNAs) are crucial for the occurrence and development of OS. The purpose of this study was to explore the expression and role of a novel circRNA circ_000203 in OS and elucidate the underlying mechanism. circ_000203 was demonstrated highly expressed in OS cell lines and tissues, and circ_000203 knockdown significantly inhibited OS progression in vitro and in vivo. Furthermore, we found that circ_000203 is a sponge of miR-26b-5p, an upstream regulator of bone morphogenetic protein receptor 2 (BMPR2). Thus, the overexpression of BMPR2 could reduce the inhibitory effect on OS progression. This indicates that knockdown of circ_000203 suppresses OS progression through microRNA (miRNA)-mediated BMPR2 downregulation. Our findings provide important insights for understanding the occurrence and development of OS.
Seasonal influenza activity typically peaks in the winter months but plummeted globally during the current coronavirus disease 2019 (COVID-19) pandemic. Unraveling lessons from influenza's unprecedented low profile is critical in informing preparedness for incoming influenza seasons. Here, we explored a country-specific inference model to estimate the effects of mask-wearing, mobility changes (international and domestic), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) interference in China, England, and the United States. We found that a one-week increase in mask-wearing intervention had a percent reduction of 11.3%–35.2% in influenza activity in these areas. The one-week mobility mitigation had smaller effects for the international (1.7%–6.5%) and the domestic community (1.6%–2.8%). In 2020–2021, the mask-wearing intervention alone could decline percent positivity by 13.3–19.8. The mobility change alone could reduce percent positivity by 5.2–14.0, of which 79.8%–98.2% were attributed to the deflected international travel. Only in 2019–2020, SARS-CoV-2 interference had statistically significant effects. There was a reduction in percent positivity of 7.6 (2.4–14.4) and 10.2 (7.2–13.6) in northern China and England, respectively. Our results have implications for understanding how influenza evolves under non-pharmaceutical interventions and other respiratory diseases and will inform health policy and the design of tailored public health measures.
Prolonged half-life of protein-based therapeutics can improve drug efficacy. However, the impact of drug half-life on gene therapy, which inherently provides long-lasting production of the desired therapeutic protein, remains unclear. In this study, several proteins with extended half-lives were engineered by fusion with the soluble monomeric immunoglobulin G 1 (IgG1) fragment crystallizable (sFc) or Fc region of IgG in adeno-associated virus (AAV)-delivered gene therapy. It was demonstrated that extending the half-life of a small-sized bifunctional protein and fibroblast growth factor 21 (FGF21) significantly increased their concentrations in the bloodstream circulation. Moreover, the half-life extension of AAV-delivered FGF21 resulted in a remarkable reduction in liver injury and blood glucose, and improved glucose tolerance and insulin sensitivity in type 2 diabetes mellitus animal models. These results demonstrate the therapeutic potential of gene therapy with prolonged drug half-life in the treatment of human diseases.
Denitrifying bioreactors (DNBRs) are widely used to reduce excess nitrate from agricultural drainage. Their performance depends on the physical and chemical properties of the substrate. Common substrate types have been partly reviewed in previous studies. However, few studies have attempted to determine a generalized pattern for the role of substrate type in nitrate removal. This study summarizes 41 types of
substrates using a dataset collected from 63 peer-reviewed articles, which include 219 independent DNBR units. The substrates are classified into four groups: ① natural carbon (NC), such as woodchips; ② non-natural carbon (NNC), such as biodegradable polymers (e.g., polycaprolactone (PCL) and waste products (e.g., cardboard); ③ inorganic materials (IMs), such as non-carbon materials (e.g., iron oxide); and④multiple materials (MMs), such as a mixture of the above materials. These materials are compared and evaluated through a meta-analysis of nitrate removal rate (NRR; N removal (g∙m–3∙d–1)) and nitrate removal efficiency (NRE). This study reviews substrate performance (NRR and NRE), potential mechanisms, pollution swapping, and cost analysis. Our analysis indicates that woodchips and corncobs are the most cost-effective substrates among NCs. In a comparison of all the studied substrates, MM substrates are recommended as the optimal substrates, especially woodchip-based and corncob-based substrates, which have great potential for improvement. This analysis can assist in optimizing the design of DNBRs to meet the environmental, economic, and practical requirements of users.