Antibiotic resistant bacteria (ARB) with antibiotic resistance genes (ARGs) can reduce or eliminate the effectiveness of antibiotics and thus threaten human health. The United Nations Environment Programme considers antibiotic resistance the first of six emerging issues of concern. Advanced oxidation processes (AOPs) that combine ultraviolet (UV) irradiation and chemical oxidation (primarily chlorine, hydrogen peroxide, and persulfate) have attracted increasing interest as advanced water and wastewater treatment technologies. These integrated technologies have been reported to significantly elevate the efficiencies of ARB inactivation and ARG degradation compared with direct UV irradiation or chemical oxidation alone due to the generation of multiple reactive species. In this study, the performance and underlying mechanisms of UV/chlorine, UV/hydrogen peroxide, and UV/persulfate processes for controlling ARB and ARGs were reviewed based on recent studies. Factors affecting the process-specific efficiency in controlling ARB and ARGs were discussed, including biotic factors, oxidant dose, UV fluence, pH, and water matrix properties. In addition, the cost-effectiveness of the UV-based AOPs was evaluated using the concept of electrical energy per order. The UV/chlorine process exhibited a higher efficiency with lower energy consumption than other UV-based AOPs in the wastewater matrix, indicating its potential for ARB inactivation and ARG degradation in wastewater treatment. Further studies are required to address the trade-off between toxic byproduct formation and the energy efficiency of the UV/chlorine process in real wastewater to facilitate its optimization and application in the control of ARB and ARGs.
The first pandemic wave of coronavirus disease 2019 (COVID-19) induced a considerable increase in several antivirals and antibiotics in surface water. The common symptoms of COVID-19 are viral and bacterial infections, while comorbidities (e.g., hypertension and diabetes) and mental shock (e.g., insomnia and anxiety) are nonnegligible. Nevertheless, little is known about the long-term impacts of comorbidities and mental shock on organic micropollutants (OMPs) in surface waters. Herein, we monitored 114 OMPs in surface water and wastewater treatment plants (WWTPs) in Wuhan, China, between 2019 and 2021. The pandemic-induced OMP pollution in surface water was confirmed by significant increases in 26 OMP concentrations. Significant increases in four antihypertensives and one diabetic drug suggest that the treatment of comorbidities may induce OMP pollution. Notably, cotinine (a metabolite of nicotine) increased 155 times to 187 ng·L−1, which might be associated with increased smoking. Additionally, the increases in zolpidem and sulpiride might be the result of worsened insomnia and depression. Hence, it is reasonable to note that mental-health protecting drugs/behavior also contributed to OMP pollution. Among the observed OMPs, telmisartan, lopinavir, and ritonavir were associated with significantly higher ecological risks because of their limited WWTP-removal rate and high ecotoxicity. This study provides new insights into the effects of comorbidities and mental shock on OMPs in surface water during a pandemic and highlights the need to monitor the fate of related pharmaceuticals in the aquatic environment and to improve their removal efficiencies in WWTPs.
The Stockholm Convention on Persistent Organic Pollutants (POPs) is a legally binding instrument for 186 Parties (status: April 2023). Accordingly, among other responsibilities, countries are obliged to report the production, import, or export of the POPs listed in Annexes A, B, or C; provide information to registers; maintain inventories; and monitor the presence of POPs in the environment. In the broader context of international chemicals and waste management, producer responsibilities, harmonized reporting, and compliance with national and international regulations, Ecuador has addressed the newly listed group of perfluorinated alkyl substances (PFAS) in its national implementation plan and sent selected products from its national market for PFAS analysis. The products analyzed came from the initially listed fields of specific exemptions and acceptable purposes, including: fire-fighting foams; photographic aids; greasers/degreasers; various kinds of paper/packaging; textiles; and leather, coatings, cleaners, metal plating, and pesticides. Our results showed that the three PFAS presently listed in the Stockholm Convention could be quantified in only a few samples; additional PFAS, not yet listed in the Convention also had low detection frequencies. Although the number of samples was limited, the samples covered a large spectrum of sample matrices, making it possible to conclude that—once these products become waste and are regulated under the Basel Convention—they would not constitute a disposal problem. Nevertheless, verification of the presence of PFAS in products on the market is expected to pose an analytical challenge for both, developed and developing countries.
Municipal solid waste (MSW) is an important destination for abandoned plastics. During the waste disposal process, large plastic debris is broken down into microplastics (MPs) and released into the leachate. However, current research only focuses on landfill leachates, and the occurrence of MPs in other leachates has not been studied. Therefore, herein, the abundance and characteristics of MPs in three types of leachates, namely, landfill leachate, residual waste leachate, and household food waste leachate, were studied, all leachates were collected from the largest waste disposal center in China. The results showed that the average MP abundances in the different types of leachates ranged from (129 ± 54) to (1288 ± 184) MP particles per liter (particles·L−1) and the household food waste leachate exhibited the highest MP abundance (p < 0.05). Polyethylene (PE) and fragments were the dominant polymer type and shape in MPs, respectively. The characteristic polymer types of MPs in individual leachates were different. Furthermore, the conditional fragmentation model indicated that the landfilling process considerably affected the size distribution of MPs in leachates, leading to a higher percentage (> 80%) of small MPs (20-100 μm) in landfill leachates compared to other leachates. To the best of our knowledge, this is the first study discussing the sources of MPs in different leachates, which is important for MP pollution control during MSW disposal.
Microplastics (MPs; < 5 mm) have become one of the most prominent global environmental pollution problems. MPs can spread to high altitudes through atmospheric transport and can be deposited by rainfall or snowfall, potentially threatening the structure and function of natural ecosystems. MPs in terrestrial and aquatic ecosystems alter the growth and functional characteristics of organisms. However, little attention has been given to the possible harm associated with MPs deposited in snow, particularly in the context of global climate warming. MPs collected from surface snow in the Inner Mongolia Plateau, China, were used for quantitative analysis and identification. The results showed that MPs were easily detected, and the related concentration was approximately (68 ± 10)-(199 ± 22) MPs·L−1 in snow samples. Fibers were the most common morphology, the polymer composition was largely varied, and the abundance and composition of MPs were linked to human activity to a great extent. High-throughput sequencing results showed that the composition and abundance of microorganisms also differed in snow samples from areas with different MP pollution characteristics, indicating a considerable difference in microbial functional diversity. MPs may have an interference effect on the individual growth and functional expression of microorganisms in snow. In addition, the results showed that functional living areas (e.g., landfills and suburban areas) in cities play an important role in the properties of MPs. For instance, the highest abundance of MPs was found in thermal power plants, whereas the abundance of polymers per sample was significantly lower in the suburban area. The MP contaminants hidden in snow can alter microbial structure and function and are therefore a potential threat to ecosystem health.
Despite the extensive application of advanced oxidation processes (AOPs) in water treatment, the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number of factors. Halogen moieties exhibit strong resistance to oxidative radicals, affecting the dehalogenation and detoxification efficiencies. To address these limitations of AOPs, advanced reduction processes (ARPs) have been proposed. Herein, a novel nucleophilic reductant—namely, the carbon dioxide radical anion ($\mathrm{CO}_{2}^{·-}$) —is introduced for the simultaneous degradation, dehalogenation, and detoxification of florfenicol (FF), a typical halogenated antibiotic. The results demonstrate that FF is completely eliminated by $ \mathrm{CO}_{2}^{·-}$, with approximately 100% of Cl− and 46% of F− released after 120 min of treatment. Simultaneous detoxification is observed, which exhibits a linear response to the release of free inorganic halogen ions (R2 = 0.97, p < 0.01). The formation of halogen-free products is the primary reason for the superior detoxification performance of this method, in comparison with conventional hydroxyl-radical-based AOPs. Products identification and density functional theory (DFT) calculations reveal the underlying dehalogenation mechanism, in which the chlorine moiety of FF is more susceptible than other moieties to nucleophilic attack by $ \mathrm{CO}_{2}^{·-}$. Moreover, $ \mathrm{CO}_{2}^{·-}$- based ARPs exhibit superior dehalogenation efficiencies (> 75%) in degrading a series of halogenated antibiotics, including chloramphenicol (CAP), thiamphenicol (THA), diclofenac (DLF), triclosan (TCS), and ciprofloxacin (CIP). The system shows high tolerance to the pH of the solution and the presence of natural water constituents, and demonstrates an excellent degradation performance in actual groundwater, indicating the strong application potential of $ \mathrm{CO}_{2}^{·-}$-based ARPs in real life. Overall, this study elucidates the feasibility of $ \mathrm{CO}_{2}^{·-}$ for the simultaneous degradation, dehalogenation, and detoxification of halogenated antibiotics and provides a promising method for their regulation during water or wastewater treatment.
The degradation of micropollutants in water via ultraviolet (UV)-based advanced oxidation processes (AOPs) is strongly dependent on the water matrix. Various reactive radicals (RRs) formed in UV-AOPs have different reaction selectivities toward water matrices and degradation efficiencies for target micropollutants. Hence, process selection and optimization are crucial. This study developed a facilitated prediction method for the photon fluence-based rate constant for micropollutant degradation (k′p,MP) in various UV-AOPs by combining model simulation with portable measurement. Portable methods for measuring the scavenging capacities of the principal RRs (RRSCs) involved in UV-AOPs (i.e., $ \mathrm{HO}^{·}$, $ \mathrm{SO}_{4}^{·-}$, and $ \mathrm{Cl}^{·}$) using a mini-fluidic photoreaction system were proposed. The simulation models consisted of photochemical, quantitative structure–activity relationship, and radical concentration steady-state approximation models. The RRSCs were determined in eight test waters, and a higher RRSC was found to be associated with a more complex water matrix. Then, by taking sulfamethazine, caffeine, and carbamazepine as model micropollutants, the k′p,MP values in various UV-AOPs were predicted and further verified experimentally. A lower k′p,MP was found to be associated with a higher RRSC for a stronger RR competition; for example, k′p,MP values of 130.9 and 332.5 m2·einstein–1, respectively, were obtained for carbamazepine degradation by UV/H2O2 in the raw water (RRSC = 9.47 × 104 s−1) and sand-filtered effluent (RRSC = 2.87 × 104 s−1) of a drinking water treatment plant. The developed method facilitates process selection and optimization for UV-AOPs, which is essential for increasing the efficiency and cost-effectiveness of water treatment.
Transparent photoresists with a high refractive index (RI) and high transmittance in visible wavelengths have promising functionalities in optical fields. This work reports a kind of tunable optical material composed of titanium dioxide nanoparticles embedded in acrylic resin with a high RI for ultraviolet (UV)-imprint lithography. The hybrid film exhibits a tunable RI of up to 1.67 (589 nm) after being cured by UV light, while maintaining both a high transparency of over 98% in the visible light range and a low haze of less than 0.05%. The precision machining of optical microstructures can be imprinted easily and efficiently using the hybrid resin, which acts as a light guide plate (LGP) to guide the light from the side to the top in order to conserve the energy of the display device. These preliminary studies based on both laboratory and commercial experiments pave the way for exploiting the unparalleled optical properties of nanocomposite resins and promoting their industrial application.
Lithium-ion batteries (LIBs) with the “double-high” characteristics of high energy density and high power density are in urgent demand for facilitating the development of advanced portable electronics. However, the lithium ion (Li+)-storage performance of the most commercialized lithium cobalt oxide (LiCoO2, LCO) cathodes is still far from satisfactory in terms of high-voltage and fast-charging capabilities for reaching the double-high target. Herein, we systematically summarize and discuss high-voltage and fast-charging LCO cathodes, covering in depth the key fundamental challenges, latest advancements in modification strategies, and future perspectives in this field. Comprehensive and elaborated discussions are first presented on key fundamental challenges related to structural degradation, interfacial instability, the inhomogeneity reactions, and sluggish interfacial kinetics. We provide an instructive summary of deep insights into promising modification strategies and underlying mechanisms, categorized into element doping (Li-site, cobalt-/oxygen-site, and multi-site doping) for improved Li+ diffusivity and bulk-structure stability; surface coating (dielectrics, ionic/electronic conductors, and their combination) for surface stability and conductivity; nanosizing; combinations of these strategies; and other strategies (i.e., optimization of the electrolyte, binder, tortuosity of electrodes, charging protocols, and pre-lithiation methods). Finally, forward-looking perspectives and promising directions are sketched out and insightfully elucidated, providing constructive suggestions and instructions for designing and realizing high-voltage and fast-charging LCO cathodes for next-generation double-high LIBs.
As people live longer, the burden of aging-related brain diseases, especially dementia, is increasing. Brain aging increases the risk of cognitive impairment, which manifests as a progressive loss of neuron function caused by the impairment of synaptic plasticity via disrupting lipid homeostasis. Therefore, supplemental dietary lipids have the potential to prevent brain aging. This review summarizes the important roles of dietary lipids in brain function from both structure and mechanism perspectives. Epidemiological and animal studies have provided evidence of the functions of polyunsaturated fatty acids (PUFAs) in brain health. The results of interventions indicate that phospholipids—including phosphatidylcholine, phosphatidylserine, and plasmalogen—are efficient in alleviating cognitive impairment during aging, with plasmalogen exhibiting higher efficacy than phosphatidylserine. Plasmalogen is a recognized nutrient used in clinical trials due to its special vinyl ether bonds and abundance in the postsynaptic membrane of neurons. Future research should determine the dose-dependent effects of plasmalogen in alleviating brain-aging diseases and should develop extraction and storage procedures for its clinical application.
Hydrogel- based tissue-engineered skin has attracted increased attention due to its potential to restore the structural integrity and functionality of skin. However, the mechanical properties of hydrogel scaffolds and natural skin are substantially different. Here, we developed a polyvinyl alcohol (PVA)/acrylamide based interpenetrating network (IPN) hydrogel that was surface modified with polydopamine (PDA) and termed Dopa-gel. The Dopa-gel exhibited mechanical properties similar to native skin tissue and a superior ability to modulate paracrine functions. Furthermore, a tough scaffold with tensile resistance was fabricated using this hydrogel by three-dimensional printing. The results showed that the interpenetration of PVA, alginate, and polyacrylamide networks notably enhanced the mechanical properties of the hydrogel. Surface modification with PDA endowed the hydrogels with increased secretion of immunomodulatory and proangiogenic factors. In an in vivo model, Dopa-gel treatment accelerated wound closure, increased vascularization, and promoted a shift in macrophages from a proinflammatory M1 phenotype to a prohealing and anti-inflammatory M2 phenotype within the wound area. Mechanistically, the focal adhesion kinase (FAK)/extracellular signal-related kinase (ERK) signaling pathway may mediate the promotion of skin defect healing by increasing paracrine secretion via the Dopa-gel. Additionally, proangiogenic factors can be induced through Rho-associated kinase-2 (ROCK-2)/vascular endothelial growth factor (VEGF)-mediated paracrine secretion under tensile stress conditions. Taken together, these findings suggest that the multifunctional Dopa-gel, which has good mechanical properties similar to those of native skin tissue and enhanced immunomodulatory and angiogenic properties, is a promising scaffold for skin tissue regeneration.
With the aging population, intertrochanteric femur fracture in the elderly has become one of the most serious public health issues and a hot topic of research in trauma orthopedics. Due to the limitations of internal fixation techniques and the insufficient mechanical design of nails, the occurrence of complications delays patient recovery after surgical treatment. Design of a proximal femur bionic nail (PFBN) based on Zhang’s N triangle theory provides triangular supporting fixation, which dramatically decreases the occurrence of complications and has been widely used for clinical treatment of unstable intertrochanteric femur fracture worldwide. In this work, we developed an equivalent biomechanical model to analyze improvement in bone remodeling of unstable intertrochanteric femur fracture through PFBN use. The results show that compared with proximal femoral nail antirotation (PFNA) and InterTan, PFBN can dramatically decrease the maximum strain in the proximal femur. Based on Frost’s mechanostat theory, the local mechanical environment in the proximal femur can be regulated into the medium overload region by using a PFBN, which may render the proximal femur in a state of physiological overload, favoring post-operative recovery of intertrochanteric femur fracture in the elderly. This work shows that PFBN may constitute a panacea for unstable intertrochanteric femur fracture and provides insights into improving methods of internal fixation.
The construction of extraterrestrial bases has become a new goal in the active exploration of deep space. Among the construction techniques, in situ resource-based construction is one of the most promising because of its good sustainability and acceptable economic cost, triggering the development of various types of extraterrestrial construction materials. A comprehensive survey and comparison of materials from the perspective of performance was conducted to provide suggestions for material selection and optimization. Thirteen types of typical construction materials are discussed in terms of their reliability and applicability in extreme extraterrestrial environment. Mechanical, thermal and optical, and radiation-shielding properties are considered. The influencing factors and optimization methods for these properties are analyzed. From the perspective of material properties, the existing challenges lie in the comprehensive, long-term, and real characterization of regolith-based construction materials. Correspondingly, the suggested future directions include the application of high-throughput characterization methods, accelerated durability tests, and conducting extraterrestrial experiments.
Land use/land cover represents the interactive and comprehensive influences between human activities and natural conditions, leading to potential conflicts among natural and human-related issues as well as among stakeholders. This study introduced economic standards for farmers. A hybrid approach (CA-ABM) of cellular automaton (CA) and an agent-based model (ABM) was developed to effectively deal with social and land-use synergic issues to examine human-environment interactions and projections of land-use conversions for a humid basin in south China. Natural attributes and socioeconomic data were used to analyze land use/land cover and its drivers of change. The major modules of the CA-ABM are initialization, migration, assets, land suitability, and land-use change decisions. Empirical estimates of the factors influencing the urban land-use conversion probability were captured using parameters based on a spatial logistic regression (SLR) model. Simultaneously, multicriteria evaluation (MCE) and Markov models were introduced to obtain empirical estimates of the factors affecting the probability of ecological land conversion. An agent-based CA-SLR-MCE-Markov (ABCSMM) land-use conversion model was proposed to explore the impacts of policies on land-use conversion. This model can reproduce observed land-use patterns and provide links for forest transition and urban expansion to land-use decisions and ecosystem services. The results demonstrated land-use simulations under multi-policy scenarios, revealing the usefulness of the model for normative research on land-use management.
This article proposes and demonstrates a retrodirective array (RDA) for two-way wireless communication with automatic beam tracking. The proposed RDA is enabled by specifically designed chips made using a domestic complementary metal-oxide semiconductor (CMOS) process. The highly integrated CMOS chip includes a receiving (Rx) chain, a transmitting (Tx) chain, and a unique tracking phase-locked loop (PLL) for the crucial conjugated phase recovery in the RDA. This article also proposes a method to reduce the beam pointing error (BPE) in a conventional RDA. To validate the above ideas simply yet without loss of generality, a 2.4 GHz RDA is demonstrated through two-way communication links between the Rx and Tx chains, and an on-chip quadrature coupler is designed to achieve a non-retrodirective signal suppression of 23 dBc. The experimental results demonstrate that the proposed RDA, which incorporates domestically manufactured low-cost 0.18 μm CMOS chips, is capable of automatically tracking beams covering ±40° with a reduced BPE. Each CMOS chip in the RDA has a compact size of 4.62 mm2 and a low power consumption of 0.15 W. To the best of the authors’ knowledge, this is the first research to demonstrate an RDA with a fully customized CMOS chip for wireless communication with automatic beam tracking.
Complex networked systems, which range from biological systems in the natural world to infrastructure systems in the human-made world, can exhibit spontaneous recovery after a failure; for example, a brain may spontaneously return to normal after a seizure, and traffic flow can become smooth again after a jam. Previous studies on the spontaneous recovery of dynamical networks have been limited to undirected networks. However, most real-world networks are directed. To fill this gap, we build a model in which nodes may alternately fail and recover, and we develop a theoretical tool to analyze the recovery properties of directed dynamical networks. We find that the tool can accurately predict the final fraction of active nodes, and the prediction accuracy decreases as the fraction of bidirectional links in the network increases, which emphasizes the importance of directionality in network dynamics. Due to different initial states, directed dynamical networks may show alternative stable states under the same control parameter, exhibiting hysteresis behavior. In addition, for networks with finite sizes, the fraction of active nodes may jump back and forth between high and low states, mimicking repetitive failure-recovery processes. These findings could help clarify the system recovery mechanism and enable better design of networked systems with high resilience.
Electron beam-directed energy deposition (EB-DED) has emerged as a promising wire-based metal additive manufacturing technique. However, the effects of EBs on pendant droplets at wire tips have not yet been determined. The aim of this study is to enhance the understanding of this action by analyzing the mechanism of droplet oscillation. The pendant droplet oscillation phenomenon hinders the stable transfer of droplets to the molten pool and limits the feasibility of manufacturing complex lattice structures by EB-DED. Hence, another aim of this study is to create an oscillation suppression method. An escalating asymmetric amplitude is the main characteristic of droplet oscillation. The primary oscillation-inducing force is the recoil force generated from the EB-acted local surface of the droplet. The physical mechanism of this force is the rapid increase and uneven distribution of the local surface temperature caused by the partial action of the EB. The prerequisites for droplet oscillation include vacuum conditions, high power densities, and bypass wire feeding processes. The proposed EB-dynamic surrounding melting (DSM) method can be applied to conveniently and effectively suppress oscillations, enable the accurate transfer of droplets to the molten pool, and achieve stable processes for preparing the strut elements of lattice structures. Lowering the temperature and improving the uniformity of its distribution are the mechanisms of oscillation suppression in EB-DSM. In this study, the physical basis for interpreting the mechanism by which EBs act on droplets and the technical basis for using EB-DED to prepare complex lattice structure parts are provided.
In response to the problems of excessive greenhouse-gas and particulate emissions and the low traction efficiency of conventional diesel tractors in the field, a purely electric wheel-side drive tractor was studied, including an electric motor drive system, a battery ballast system, and an electro-hydraulic suspension system. This paper develops a dynamics model of an electric tractor-ploughing unit under complex soil conditions, leading to the proposal of an active control method for drive wheel torque and a joint control method for the traction force of the suspension system and the front- and rear-axle loads of a tractor. Finally, the tractor is prototyped and assembled, and ploughing tests are carried out. The ploughing results show that the active torque-distribution control method proposed in this study reduces the tractor slip by 14.83% and increases the traction efficiency by 10.28% compared with the average torque-distribution mode. Compared with the conventional traction control mode, the joint control method for traction and ballast proposed in this paper results in a 3.7% increase in traction efficiency, a 15.05% decrease in slip, and a 4.9% reduction in total drive motor energy consumption. This study will help to improve the operation quality and traction efficiency of electric tractors in complex soil conditions.
