Effect of co-toxicity of lead and nanoplastics on the flavonoid biosynthetic pathway in dandelion (Taraxacum asiaticum Dahlst).

MAIN CONCLUSION: Negatively charged carboxy-polystyrene (CPS) and positively charged amino-polystyrene (NPS) could significantly inhibit the biomass and flavonoid content of dandelion roots and leaves, and the inhibitory effect of NPS was stronger than that of CPS. The increasingly serious pollution of microplastics and heavy metals is likely to affect the efficacy of flavonoids synthesized by dandelion in natural medicine fields. Therefore, we combined hydroponic experiments with computational chemistry (Gaussian and autodock analysis) to explore the mechanism by which amino-polystyrene (NPS), carboxy-polystyrene (CPS), and lead affect the flavonoid biosynthetic pathway in dandelion (Taraxacum asiaticum Dahlst). Our results show that CPS and NPS could significantly inhibit the biomass and flavonoid content of dandelion roots and leaves, and the inhibitory effect of NPS was stronger than that of CPS. Mechanistic studies showed that CPS and NPS increased the content of O2- and H2O2 in dandelion roots and leaves, causing membrane lipid peroxidation, resulting in cell damage and decreased biomass. CPS and NPS inhibited related enzymatic activities by affecting their tertiary structures, resulting in a decrease in phenolic acid, coumaroyl-CoA, and flavonoid content. Dandelion preferred to absorb positively charged NPS compared to negatively charged CPS, but CPS inhibited the uptake of Pb by dandelion more strongly than NPS. Pb promoted CPS agglomeration and increased the surface positive charge of CPS through coordination bonds and hydrogen bonds, so more CPS entered dandelion under CPS + Pb treatment than under CPS alone. Although NPS and CPS reduced the uptake of Pb by dandelion, the biomass and flavonoid contents of dandelion were lower than those of single Pb treatment because of the higher toxicity of NPS and CPS than Pb. Pb significantly increased the effect of CPS on the root biomass of dandelion compared with CPS alone by increasing the positive charge of CPS. We suggest that microplastics with different charges and lead composite pollution inhibit dandelion flavonoid biosynthesis and provide a reference for the loss of dandelion medicinal components and economic value.

Nacre-Inspired Strong and Multifunctional Soy Protein-Based Nanocomposite Materials for Easy Heat-Dissipative Mobile Phone Shell.

Inspired by the hierarchically ordered "brick and mortar" (BM) architecture of natural nacre, in this study a rational assembly of boron nitride (BN) nanosheets was introduced into a mixture of trimethylolpropane triglycidyl ether (TTE) and soy protein isolate (SPI), and a strong and multifunctional SPI-based nanocomposite film with multinetwork structure was synthesized. At a low BN loading (<0.5%), the resulting multifunctional film was flexible, antiultraviolet, and nearly transparent and also displayed good thermal diffusion ability and exhibited an excellent combination of high tensile strength (36.4 MPa) and thermal conductivity (TC, 2.40 W·m-1·K-1), surpassing the performances of various types of petroleum-based plastics (displayed a tensile strength ranging from 1.9 to 21 MPa and TC ranging from 0.55-2.13 W·m-1·K-1), including nine different types of materials currently utilized for mobile phone shells, suggesting its vast potential in practical applications.

Effect of microplastics and arsenic on nutrients and microorganisms in rice rhizosphere soil.

The presence of microplastics and arsenic in soil can endanger crop growth; therefore, their effects on the properties of rhizosphere soil should be evaluated. Large (10-100 µm) and small (0.1-1 µm) polystyrene (PSMP) and polytetrafluorethylene (PTFE) particles were added to soil with different arsenic concentrations (1.4, 24.7, and 86.3 mg kg-1) to investigate the combined effect of microplastics and arsenic pollution on rice rhizosphere soil. After the addition of PSMP and PTFE, pH, arsenic (V) and arsenic (III) in the soil were observed to decrease. The interaction of arsenic with PSMP and PTFE resulted in this phenomenon, leading to a decrease of arsenic bioavailability in the soil. PSMP, PTFE, and arsenic reduced the abundance of Proteobacteria, increased the abundance of Chloroflexi and Acidobacteria, and inhibited soil urease, acid phosphatase, protease, dehydrogenase, and peroxidase activity via affecting the tertiary structure of the enzyme. PSMP, PTFE, and arsenic also reduced the available nitrogen and phosphorus content in the soil. Arsenic increased the soil organic matter content, whereas PSMP and PTFE reduced the organic matter content. Furthermore, microplastics inhibited the effects of arsenic on the microbial and chemical properties of the rhizosphere soil. This study revealed the effects of microplastic and arsenic pollution on rice rhizosphere microorganisms and nutrients, and elucidated the mechanism by which these pollutants retard crop growth in the designed growth medium.

Effects of sertraline hydrochloride with As(III) or Cd on rhizosphere micro-environment and root endophytes in rice.

This study investigated the effects of the antidepressant sertraline hydrochloride (Ser-HCI) on rice physiology when combined with arsenic (III) or cadmium. Hydroponic experiments revealed that combined lower concentrations (0.2 and 0.6 mg L-1) of Ser-HCl and As (III) or Cd increased rice biomass and reduced pH and low molecular weight organic acids. The fluorescence intensity was enhanced with Ser-HCl and As-only treatments, with a significant difference (p < 0.05) in the dissolved organic matter index. There was a decrease in endophyte-specific operational taxonomic units, with proteobacteria dominating the rice root endophytes. The addition of Ser-HCl resulted in the Verrucomicrobiota increasing by 6.4 times, which was positively correlated with malic acid and negatively correlated with pH. Functional annotation highlighted alterations in carbohydrate metabolism pathways. This study provides insights into the interactive effects of Ser-HCl on rice when combined with As (III) or Cd, addressing gaps in our understanding of the impact of antidepressants on plant systems.

Impact of microplastics on microbial-mediated soil sulfur transformations in flooded conditions.

As emerging environmental pollutants, microplastics have become a crucial focus in environmental science research. Despite this, the impact of microplastics on soil in flooding conditions remains largely unexplored. Addressing this gap, our study examined the influence of polystyrene (PS) and polyphenylene sulfide (PPS) on the microbial populations in black soil, meadow soil, and paddy soil under flooded conditions. Given the significant regulatory influence exerted by microorganisms on sulfur transformations, our study was primarily focused on evaluating the microbial contributions to alterations in soil sulfur species. Our findings revealed several notable trends: In black soil, both PS and PPS led to a marked increase in the abundance of γ-proteobacteria and Subgroup_6, while reducing Clostridia. Ignavibacteria were found to be lower under PPS compared to PS. In meadow soil, the introduction of PPS resulted in increased levels of KD4-96 and γ-proteobacteria, while α-proteobacteria decreased. Chloroflexia under PPS was observed to be lower than under PS conditions. In paddy soil, our study identified a significant rise in Bacteroidia and Ignavibacteria, accompanied by a decrease in α-proteobacteria and γ-proteobacteria. γ-proteobacteria levels under PPS were notably higher than those under PS conditions. These shifts in microbial communities induced by both PS and PPS had a direct impact on adenosine 5'-phosphosulfate reductase, sulfite reductase, and polysulfide dioxygenase. Consequently, these changes led to soil organic sulfur decrease and sulfide increase. This study not only offers a theoretical framework but also provides empirical evidence for understanding the effects of microplastics on soil microorganisms and their role in regulating nutrient cycling, particularly in flood-prone conditions. Furthermore, this study underscores the importance of ensuring an adequate supply of sulfur in agricultural practices, such as rice and lotus root cultivation, to support optimal crop growth in the presence of microplastic pollution.

Response of garlic (Allium sativum L.) to the combined toxicity of microplastics and arsenic.

The extensive utilization of mulch films in agricultural settings, coupled with the persistence of microplastic remnants in soil following the natural degradation of plastics, has given rise to detrimental microplastic impacts on crops. Arsenic (As) contamination in the environment is known to accumulate in crops through aquatic pathways or soil. Garlic (Allium sativum L.), a globally popular crop and seasoning, contains alliin, a precursor of its flavor compounds with medicinal properties. While alliin exhibits antimicrobial and antioxidant effects in garlic, its response to microplastics and arsenic has not been thoroughly investigated, specifically in terms of microplastic or As uptake. This study aimed to explore the impact of varied stress concentrations of microplastics on the toxicity, migration, and accumulation of As compounds. Results demonstrated that polystyrene (PS) fluorescent microspheres, with an 80 nm diameter, could permeate garlic bulbs through the root system, accumulating within vascular tissues and intercellular layers. Low concentrations of PS (10 and 20 mg L-1) and As (2 mg L-1) mitigated the production and accumulation of reactive oxygen species (ROS) and antioxidant enzymes in garlic. Conversely, garlic exhibited reduced root vigor, substance uptake, and translocation when treated with elevated As concentrations (4 mg L-1) in conjunction with PS concentrations of 40 and 80 mg L-1. An escalation in PS concentration facilitated As transport into bulbs but led to diminished As accumulation and biomass in the root system. Notably, heightened stress levels weakened garlic's antioxidant defense system, encompassing sulfur allicin and phytochelatin metabolism, crucial for combating the phytotoxicity of PS and As. In summary, PS exerted a detrimental influence on garlic, exacerbating As toxicity. The findings from this study offer insights for subsequent investigations involving Liliaceae plants.

Desirable Strong and Tough Adhesive Inspired by Dragonfly Wings and Plant Cell Walls.

The production of wood-based panels has a significant demand for mechanically strong and flexible biomass adhesives, serving as alternatives to nonrenewable and toxic formaldehyde-based adhesives. Nonetheless, plywood usually exhibits brittle fracture due to the inherent trade-off between rigidity and toughness, and it is susceptible to damage and deformation defects in production applications. Herein, inspired by the microstructure of dragonfly wings and the cross-linking structure of plant cell walls, a soybean meal (SM) adhesive with great strength and toughness was developed. The strategy was combined with a multiple assembly system based on the tannic acid (TA) stripping/modification of molybdenum disulfide (MoS2@TA) hybrids, phenylboronic acid/quaternary ammonium doubly functionalized chitosan (QCP), and SM. Motivated by the microstructure of dragonfly wings, MoS2@TA was tightly bonded with the SM framework through Schiff base and strong hydrogen bonding to dissipate stress energy through crack deflection, bridging, and immobilization. QCP imitated borate chemistry in plant cell walls to optimize interfacial interactions within the adhesive by borate ester bonds, boron-nitrogen coordination bonds, and electrostatic interactions and dissipate energy through sacrificial bonding. The shear strength and fracture toughness of the SM/QCP/MoS2@TA adhesive were 1.58 MPa and 0.87 J, respectively, which were 409.7% and 866.7% higher than those of the pure SM adhesive. In addition, MoS2@TA and QCP gave the adhesive good mildew resistance, durability, weatherability, and fire resistance. This bioinspired design strategy offers a viable and sustainable approach for creating multifunctional strong and tough biobased materials.

Investigating the impact of microplastics on sulfur mineralization in different soil types: A mechanism study.

Microplastics can affect the physicochemical properties of soil and soil microorganisms, potentially resulting in changes in the soil sulfur mineralization and its capacity to supply available sulfur. However, the specific mechanisms underlying these effects remain unclear. We performed soil microcosm experiments, in which the effects of polystyrene (PS) and polyphenylene sulfide (PPS) microplastics on sulfur mineralization were examined in black, meadow, and paddy soils under flooded and dry conditions. Under dry condition, the presence of PS and PPS microplastics impeded sulfur (S) mineralization in black and paddy soils, but promoted sulfur mineralization in meadow soil. The size of microplastics was identified as the primary factor influencing sulfur mineralization in black soil, while in meadow soil, it was influenced by the microplastics type. In the case of paddy soil, the concentration of microplastics was the key factor affecting sulfur mineralization. During the flooding period, PS and PPS microplastics in black and paddy soils curtailed sulfur mineralization, however expedited sulfur mineralization in meadow soil, with PS enhancing soil sulfur mineralization more pronouncedly than PPS in black soil. The type and concentration of microplastics were identified as the main factors affecting sulfur mineralization in black soil, while in paddy soil, it was influenced by the size of microplastics. The principal regulating factors of soil sulfur mineralization were the sulphatase and arylsulfatase enzymes produced by Actinobacteria, Xanthomonadales, and Rhizobiales microorganisms, while organic matter and Olsen-P also had an influential role. Additionally, microplastics directly affected the structure of soil enzymes, thereby altering soil enzyme activities. This study provided insights into the mechanism by which microplastics affect soil sulfur mineralization, offering significant implications for assessing the influence of microplastics on soil sulfur availability and making informed decisions about sulfur application in future agricultural practices.

Programmable and Shape-Color Synchronous Dual-Response Wood with Thermal Stimulus.

Stimuli-responsive materials exhibit huge potential in sensors, actuators, and electronics; however, their further development for reinforcement, visualization, and biomass-incorporation remains challenging. Herein, based on the impregnation of thermochromic microcapsule (TCM)-doped dynamic covalent vitrimers, a programmable shape-color dual-responsive wood (SRW-TC) was demonstrated with robust anisotropic structures and exchangeable covalent adaptable networks. Under mild conditions, the resultant SRW-TC displays feasible shape memorability and programmability, resulting from the rigidity-flexibility shift induced by the glass-transition temperature (34.99 °C) and transesterification reaction triggered by the topology freezing transition temperature (149.62 °C). Furthermore, the obtained SRW-TC possesses satisfactory mechanical performance (tensile strength of 45.70 MPa), thermal insulation (thermal conductivity of 0.27 W/m K), anisotropic light management, and benign optical properties (transmittance of 51.73% and haze of 99.67% at 800 nm). Importantly, the incorporation of compatible TCM enables SRW-TC to visualize shape memory feasibility and rigidity/flexibility switching and respond to the external thermal stimulus through the thermal-induced shape-color synchronous dual-responsiveness, which successfully demonstrates the applications of sensing temperature, grasping objects, encrypting/decoding icon messages, and so on. The proposed facile and highly effective strategy could serve as a guideline for developing high-performance multifunctional wood composite with promising intelligent applications in performance visualization, environmental sensing, materials interactivity, information dual-encryption, local precision shape and color regulation, etc.

Fabrication of bulk superhydrophobic wood by grafting porous poly(divinylbenzene) to wood structure using isocyanatoethyl methacrylate.

Superhydrophobic treatment of wood can effectively reduce the interaction between wood and moisture, avoiding deformation, cracking, mould, and other defects caused by water absorption, which can extend the service life of wood and broaden the application field. Currently, the poor abrasion resistance of superhydrophobic wood is a crucial problem limiting its widespread application, and the preparation of superhydrophobic wood with robustness, abrasion resistance, and chemical resistance remains a huge challenge. In this work, robust bulk superhydrophobic wood with excellent abrasion resistance and chemical durability was fabricated by synthesizing porous poly(divinylbenzene) in wood cell cavities using graft copolymerization and solvothermal methods. The contact angles and rolling angles on the superhydrophobic wood surface were approximately 156° and 3°, respectively. Superhydrophobicity was carried through the entire structure of the wood. Even after severe damage by abrasion and sawing, as well as tests with organic solvents and harsh environments, the superhydrophobic properties of wood remained stable. Meanwhile, the superhydrophobic wood exhibited great self-cleaning and antifouling properties. In addition, the water uptake and dimensional stability of the wood were significantly improved. This work developed a simple, efficient, and durable strategy for the fabrication of superhydrophobic wood with robustness, abrasion resistance, and chemical resistance, which was expected to be applied to the wood industry to achieve the high-value applications of wood products and extend their service life.

In Situ Synthesis of Gold Nanoparticles from Chitin Nanogels and Their Drug Release Response to Stimulation.

In this study, gold nanoparticles (AuNPs) were synthesized in situ using chitin nanogels (CNGs) as templates to prepare composites (CNGs@AuNPs) with good photothermal properties, wherein their drug release properties in response to stimulation by near-infrared (NIR) light were investigated. AuNPs with particle sizes ranging from 2.5 nm to 90 nm were prepared by varying the reaction temperature and chloroauric acid concentration. The photothermal effect of different materials was probed by near-infrared light. Under 1 mg/mL of chloroauric acid at 120 °C, the prepared CNGs@AuNPs could increase the temperature by 32 °C within 10 min at a power of 2 W/cm2. The Adriamycin hydrochloride (DOX) was loaded into the CNGs@AuNPs to investigate their release behaviors under different pH values, temperatures, and near-infrared light stimulations. The results showed that CNGs@AuNPs were pH- and temperature-responsive, suggesting that low pH and high temperature could promote drug release. In addition, NIR light stimulation accelerated the drug release. Cellular experiments confirmed the synergistic effect of DOX-loaded CNGs@AuNPs on chemotherapy and photothermal therapy under NIR radiation.

The impact of microplastics on sulfur REDOX processes in different soil types: A mechanism study.

Microplastics can potentially affect the physical and chemical properties of soil, as well as soil microbial communities. This could, in turn, influence soil sulfur REDOX processes and the ability of soil to supply sulfur effectively. However, the specific mechanisms driving these effects remain unclear. To explore this, soil microcosm experiments were conducted to assess the impacts of polystyrene (PS) and polyphenylene sulfide (PPS) microplastics on sulfur reduction-oxidation (REDOX) processes in black, meadow, and paddy soils. The findings revealed that PS and PPS most significantly decreased SO42- in black soil by 9.4%, elevated SO42- in meadow soil by 20.8%, and increased S2- in paddy soil by 20.5%. PS and PPS microplastics impacted the oxidation process of sulfur in soil by influencing the activity of sulfur dioxygenase, which was mediated by α-proteobacteria and γ-proteobacteria, and the oxidation process was negatively influenced by soil organic matter. PS and PPS microplastics impacted the reduction process of sulfur in soil by influencing the activity of adenosine-5'-phosphosulfate reductase, sulfite reductase, which was mediated by Desulfuromonadales and Desulfarculales, and the reduction process was positively influenced by soil organic matter. In addition to their impacts on microorganisms, it was found that PP and PPS microplastics directly influenced the structure of soil enzymes, leading to alterations in soil enzyme activity. This study sheds light on the mechanisms by which microplastics impact soil sulfur REDOX processes, providing valuable insights into how microplastics influence soil health and functioning, which is essential for optimizing crop growth and maximizing yield in future agricultural practices.

Effects of polystyrene nanoplastics with different functional groups on the accumulation and toxicity of Pb on dandelion.

Micro (Nano)plastics are ubiquitous in the environment and can potentially affect the toxic effects of other chemicals, such as heavy metals. Although the interaction of micro (nano)plastics and heavy metals as well as their effects on aquatic organisms have been widely investigated, studies on their influence on terrestrial plants are limited. Therefore, in this study, the effects of polystyrene (PS), carboxy-modified PS (CPS) and amino-modified PS (APS) nanoparticles on the accumulation and toxicity of Pb on dandelion (Taraxacum asiaticum Dahlst) were investigated using hydroponic cultivation. The presence of the three PS caused cell damage and destroyed the tertiary structure of the ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and dehydrogenase (DHA) enzymes, thereby inhibiting Rubisco and root activities, which hindered nutrient uptake and photosynthesis. The inhibition of APS on the biomass of dandelion was greater than that of PS and CPS. Confocal laser scanning microscope and transmission electron microscopy analysis showed that APS was more likely to enter the roots of dandelion than PS and CPS. The presence of Pb induced more PS, CPS, and APS to enter dandelion roots, and Pb aggravated PS and CPS toxicities on dandelion rather than APS toxicity. This is because the complex formed by CPS and Pb can affect the structure of Rubisco and DHA through covalent and coordination bonds, and Pb increased the surface positive charge on CPS, according to Gaussian analysis. The presence of both PS and CPS significantly reduced Pb uptake by dandelion, and they did not exacerbate the toxicity of Pb. In contrast, APS slightly inhibited Pb accumulation, but aggravated Pb toxicity in dandelion. Our findings revealed that the changes in the uptake of nanoplastics and Pb by dandelion potentially resulted in a cascade of events that increased the toxicity and inhibited the growth of dandelion seedlings.

Natural organic-inorganic hybrid structure enabled green biomass adhesive with desirable strength, toughness and mildew resistance.

Plant based proteins are green, sustainable, and renewable materials that show the potential to replace traditional formaldehyde resin. High performance plywood adhesives exhibit high water resistance, strength, toughness, and desirable mildew resistance. Adding petrochemical-based crosslinkers is not economically viable or environmentally benign; this chemical crosslinking strategy makes the imparted high strength and toughness less attractive. Herein, a green approach based on natural organic-inorganic hybrid structure enhancement is proposed. The design of soybean meal-dialdehyde chitosan-amine modified halloysite nanotubes (SM-DACS-HNTs@N) adhesive with desirable strength and toughness enhanced by covalent bonding (Schiff base) crosslinking and toughened by surface-modified nanofillers is demonstrated. Consequently, the prepared adhesive showed a wet shear strength of 1.53 MPa and work of debonding of 389.7 mJ, which increased by 146.8 % and 276.5 %, respectively, due to the cross-linking effect of organic DACS and toughening effect of inorganic HNTs@N. The introduction of DACS and Schiff base generation enhanced the antimicrobial property of the adhesive and increased the mold resistance of the adhesive and plywood. In addition, the adhesive has good economic benefits. This research creates new opportunities for developing biomass composites with desirable performance.

A polydimethylsiloxane-based sponge for water purification and interfacial solar steam generation.

A better knowledge for the design and synthesis of low-cost, novel porous materials is highly desirable in various fields such as recyclable solar desalination and liquid recycling. Herein, a polydimethylsiloxane-based sponge with a web-like three-dimensional (3D) interconnected porous structure was developed for effective recovery of liquids and the continuous interfacial solar steam generation (ISSG). The sponge is capable of conducting directional transport of oil or organic solvents at temperatures above 32 °C while automatically controlling the desorption of the organic phase below 28 °C. The synergistic combination between high light absorption (above 95 %) and light-to-heat conversion efficiency (99.87 %) resulted in a considerably high seawater evaporation rate (1.66 Kg m-2h-1) under 1 sun. The self-regeneration of the evaporator is facilitated by the salt barrier function of the large channels of the smart sponge with high hydraulic conductivity. This sponge can maintain a maximum evaporation rate up to the 5 consecutive days operation with the co-benefit of real-time regeneration and the reversible switching of the wettability. The reusable smart sponge evaporators are highly efficient in generating clean water from seawater with satisfactory ion rejection rates (above 99.6 %). As such, the prepared sponge shows great potential in environmental restoration, metal recovery, and water regeneration.

ANT(9)-Ic, a Novel Chromosomally Encoded Aminoglycoside Nucleotidyltransferase from Brucella intermedia.

Aminoglycoside-modifying enzymes are among the most important mechanisms of resistance to aminoglycoside antibiotics, typically conferring high-level resistance by enzymatic drug inactivation. Previously, we isolated a multidrug-resistant Brucella intermedia strain ZJ499 from a cancer patient, and whole-genome sequencing revealed several putative novel aminoglycoside-modifying enzyme genes in this strain. Here, we report the characterization of one of them that encodes an intrinsic, chromosomal aminoglycoside nucleotidyltransferase designated ANT(9)-Ic, which shares only 33.05% to 47.44% amino acid identity with the most closely related ANT(9)-I enzymes. When expressed in Escherichia coli, ANT(9)-Ic conferred resistance only to spectinomycin and not to any other aminoglycosides tested, indicating a substrate profile typical of ANT(9)-I enzymes. Consistent with this, deletion of ant(9)-Ic in ZJ499 resulted in a specific and significant decrease in MIC of spectinomycin. Furthermore, the purified ANT(9)-Ic protein showed stringent substrate specificity for spectinomycin with a Km value of 44.83 µM and a kcat/Km of 2.8 × 104 M-1 s-1, echoing the above observations of susceptibility testing. In addition, comparative genomic analysis revealed that the genetic context of ant(9)-Ic was conserved in Brucella, with no mobile genetic elements found within its 20-kb surrounding region. Overall, our results demonstrate that ANT(9)-Ic is a novel member of the ANT(9)-I lineage, contributing to the intrinsic spectinomycin resistance of ZJ499. IMPORTANCE The emergence, evolution, and worldwide spread of antibiotic resistance present a significant global public health crisis. For aminoglycoside antibiotics, enzymatic drug modification is the most common mechanism of resistance. We identify a novel chromosomal aminoglycoside nucleotidyltransferase from B. intermedia, called ANT(9)-Ic, which shares the highest identity (47.44%) with the previously known ANT(9)-Ia and plays an important role in spectinomycin resistance of the host strain. Analysis of the genetic environment and origin of ant(9)-Ic shows that the gene and its surrounding region are widely conserved in Brucella, and no mobile elements are detected, indicating that ANT(9)-Ic may be broadly important in the natural resistance to spectinomycin of Brucella species.

A tough bio-adhesive inspired by pearl layer and arthropod cuticle structure with desirable water resistance, flame-retardancy, and antibacterial property.

Petroleum-derived formaldehyde resin adhesives are serious hazards to human health and depend on limited resources. Abundant, cheap and renewable biomass materials are expected to replace them. However, the contradictory mechanisms of high mechanical strength and fracture toughness affect the use of bioadhesives. Herein, a biomimetic soybean meal (SM) adhesive inspired by the structure of insect cuticles and shell pearl layer was proposed. Specifically, chitosan (CS@DA) modified 3,4-dihydroxybenzoic acid (DA, rich in catechol moiety) was anchored on molybdenum disulfide nanosheets (MoS2) to construct a biomimetic structure with copper hydroxide and SM substrate (SM-MoS2/CS@DA-Cu). Schiff base, ionic, and hydrogen bonding strengthened the cohesion of the adhesive. The ordered alternating stacking "brick-mortar" structure stimulated the lamellar sliding and crack deflection of MoS2, synergistically reinforcing the toughness. Compared to SM adhesive (0.57 MPa and 0.148 J), the wet shear strength and adhesion work of the SM-MoS2/CS@DA-Cu were 1.68 MPa and 0.867 J, with 194.7 % and 485.8 % increases, respectively. The multiple antimicrobial effects of CS@DA, Schiff base, and Cu2+ increased the applicability period of the adhesive to 40 days. The adhesive also displayed favorable water resistance and flame retardancy. Therefore, this peculiar and efficient biomimetic structural design inspired the development of multi-functional composites.

A novel mechanism study of microplastic and As co-contamination on indica rice (Oryza sativa L.).

Although the compound pollution of microplastics and arsenic (As) in paddy soil can affect the growth and quality of rice, relevant research on this phenomenon was limited. Therefore, we combined a pot experiment with computational chemistry to explore the effects and mechanism of polystyrene (PSMP) and polytetrafluoroethylene (PTFE) microplastics on As bioavailability. PSMP and PTFE interacted with rice root exudates through van der Waals forces, approached the rice root system, inhibited root activity, reduced the relative abundance of Geobacteria and Anaeromyxobacter, and consequently reduced the iron plaques on the root surfaces. Consequently, As uptake by the rice was inhibited. PSMP and PTFE reduced the hemoglobin content by directly destroying its tertiary structure, thereby retarding rice growth. In contrast, As increased the hemoglobin content by inducing reactive oxygen species in rice. Under the influence of PSMP, PTFE, and As, the activities of soluble starch synthase and pyrophosphorylase in rice grains were inhibited, and starch accumulation decreased. Thus, PSMP, PTFE, and As reduced rice biomass and yield owing to their physiological toxicity and adverse impacts on root activity. Grain yields in soil with an As content of 86.3 mg·kg-1, 0.5% small particle-sized PSMP, and 0.5% small particle-sized PTFE decreased by 30.7%, 20.6%, and 19.4%, respectively, compared to the control. This study determined the comprehensive mechanism through which PSMP and PTFE affect As bioavailability, which is critical for managing rice biomass and low yields in As and microplastic co-contaminated soil.

Reviewing wood-based solar-driven interfacial evaporators for desalination.

Solar‒driven interfacial water evaporation is a convenient and efficient strategy for harvesting solar energy and desalinating seawater. However, the design and fabrication of solar evaporators still challenge reliable evaporation and practical applications. Wood-based solar-driven interfacial water evaporation emerge as a promising and environmentally friendly approach for water desalinating as it provides renewable and porous structures. In recent years, surface modifications and innovative structural designs to prepare high performance wood-based evaporators is widely explored. In this review, we firstly describe the superiority of wood for the fabrication of wood-based solar evaporators, including the pore structure, chemical structure and thermal insulation. Secondly, we summarize the recent developments in wood-based evaporators from surface carbonization, decoration with photothermal materials, bulk modification and structural design, and discuss from the aspects of water transportation capacity, thermal conductivity and photothermal efficiency. Finally, based on these previous results and analysis, we highlight the remaining challenges and potential future directions, including the selection of high-efficient photothermal materials, heat and mass transfer mechanism in wood-based evaporators including large-scale production at a low cost.

Preparation of rigid polyurethane foam from lignopolyol obtained through mild oxypropylation.

Lignin, one of the main components of lignocellulose, can be used as an alternative to chemical polyols in the production of polyurethane because of its abundant phenolic and alcohol hydroxyls. Traditionally, lignin is directly applied in the preparation of polyurethane; however, modified lignin has been proved to be superior, especially that obtained by the oxypropylation reaction. Therefore, lignopolyol obtained by mild and efficient oxypropylation was utilized in the production of rigid polyurethane foam in this study. Specifically, the effects of the content of lignopolyol on the chemical structure, morphological structure, mechanical properties and thermal stability of the lignin-based rigid polyurethane foam were investigated. It was found that the compressive strength of the rigid polyurethane foam was significantly improved with the addition of lignopolyol compared with that of the pure polyurethane foam, which was attributed to the fact that oxypropylation made lignin into highly branched and functionalized polyols by transforming all phenolic hydroxyls into aliphatic hydroxyls. Moreover, when the molal weight of lignopolyol accounted for 40% of the added polyols, the generated foam showed optimal uniformity and regularity, and the compressive strength reached 0.18 MPa, meeting the requirements of industrial application, below which, the amount of undesired reactions is bound to increase. As a consequence, the added amount of lignopolyol was increased as much as possible on the basis of guaranteeing the desired properties, which was more conducive to realizing the green degradation and economic synthesis of rigid polyurethane foam.