Evaluation of Organosolv Lignin as an Oxidation Inhibitor in Bitumen.

Organosolv lignin, a natural polymer, has been used in this study as an oxidation inhibitor in bitumen. Particularly, the effect of oxidative aging on the chemical compositional changes and on the rheology of bituminous binders with organosolv lignin and the impact to inhibit oxidation in bitumen were evaluated. Firstly, after analyzing the microstructure and surface characteristics of utilized organosolv lignin, a high shear mixing procedure was followed to produce binders of different proportions of lignin in bitumen. Pressure aging vessel conditioning was applied to these binders to simulate in-field aging and a series of tests were performed. Fourier transform infrared spectroscopy was used to track the compositional changes of lignin-bitumen systems before and after aging respectively. The rheological changes due to oxidative aging in the different lignin-bitumen systems were studied by means of dynamic shear rheometer tests. Based on the spectroscopic laboratory analyses, certain proportions of organosolv lignin in bitumen have shown a potential oxidation retardation effect in bitumen since a reduction of carbonyl and sulfoxide compounds was observed. However, the addition of lignin reduced the fatigue life of bitumen and potentially led to an increase in brittle fracture sensitivity at low and medium temperatures. Nevertheless, lignin improved the rutting resistance at high temperatures. Overall, it can be concluded that organosolv lignin can suppress the oxidation of sulfur and carbon compounds in bitumen either by direct deceleration of oxidation reaction or interaction with compounds that otherwise are oxidizable, without seriously degrading the mechanical properties.

Polystyrene microplastics induce anxiety via HRAS derived PERK-NF-κB pathway.

Exposure to environmentally hazardous substances is recognized as a significant risk factor for neurological associated disorders. Among these substances, polystyrene microplastics (PS-MPs), widely utilized in various consumer products, have been reported to exhibit neurotoxicity. However, the potential association of PS-MPs with abnormal anxiety behaviors, along with the underlying molecular mechanisms and key proteins involved, remains insufficiently explored. Here, we delineated the potential mechanisms of PS-MPs-induced anxiety through proteomics and molecular investigations. We characterized the PS-MPs, observed their accumulation in the brain, leading to anxiety-like behavior in mice, which is correlated with microglia activation and pro-inflammatory response. Consistent with these findings, our studies on BV2 microglia cells showed that PS-MPs activated NF-κB-mediated inflammation resulting in the upregulation of pro-inflammatory cytokines such as TNFα and IL-1ß. Of particular significance, HRAS was identified as a key factor in the PS-MPs induced pro-inflammatory response through whole proteomics analysis, and knockdown of H-ras effectively inhibited PS-MPs induced PERK-NF-κB activation and associated pro-inflammatory response in microglia cells. Collectively, our findings highlight that PS-MPs induce anxiety of mice via the activation of the HRAS-derived PERK-NF-κB pathway in microlglia. Our results contribute valuable insights into the molecular mechanisms of PS-MPs-induced anxiety, and may offer implications for addressing neurotoxicity and prevention the adverse effects of environmentally hazardous substances, including microplastics.

Carbonyl heterocycle modified mesoporous carbon nitride in photocatalytic peroxydisulfate activation for enhanced ciprofloxacin removal: Performance and mechanism.

Polymer carbon nitride is considered to be a promising photocatalyst with broad application prospects in water treatment. However, the defects of pristine polymer carbon nitride (PCN), such as small specific surface area, fast photogenerated electron-hole recombination, and low mass transfer efficiency, limit its photocatalytic activity. In this work, by introducing 2-thiouracil into the precursor, a carbonyl heterocycle-containing mesoporous carbon nitride photocatalyst (TCN) was successfully obtained with significantly enhanced peroxydisulfate (PDS) photocatalytic activity. In this study, the modulation mechanism of carbonyl heterocycle introduction on surface electronic structure and the band structure were fully discussed by means of a combination of experiments and theoretical calculations. The carbonyl and vicinal carbon-modified heterocycles dominated the electrons, while the adjacent heptazine ring dominated the holes. The photogenerated electron-hole pair recombination efficiency and the electron transition energy barrier were greatly reduced. According to the findings of density functional theory (DFT) calculations, the introduction of carbonyl and vicinal C modulated the electronic structure of catalyst, enhanced the adsorption of PDS at the carbonyl ortho N site, which promoted the electronic interaction between TCN and PDS molecules. Experiments showed that the free radical pathway and non-radical pathway coexisted in TCN/PDS/Vis system. The reactive oxygen species were mainly derived from PDS molecules. DFT calculations provided a more comprehensive theoretical basis for the experimental results. This study provided a fresh perspective on the rational design of carbon nitride-based catalysts and the reaction mechanism of persulfate advanced oxidation systems.

Lignin peroxidase-catalyzed direct oxidation of trace organic pollutants through a long-range electron transfer mechanism: Using propranolol as an example.

In this work, lignin peroxidase (LiP) was extracted for the in vitro degradation of a persistent compound (propranolol, PPN). The results showed that 94.2% of PPN was degraded at 30 U L-1 LiP activity and 10 mg L-1 PPN. The PPN degradation rate increased from 33.5% to 94.2% when the veratryl alcohol (VA) concentration varied from 0 to 180 µM, but decreased to 73.1% with further VA addition. This phenomenon confirmed that VA was indispensable, however, it also acted as a competitive inhibitor of PPN oxidation. Computational analysis revealed that the Trp171…iron porphyrin (TRP-FeP) path was responsible for specific substrate (e.g., VA) transformation, and another long-range electron transfer (LRET) path through His-Asp…FeP (HSP-FeP) was discovered for non-specific substrate (e.g., PPN) degradation. These two electron-transfer routes shared one catalytic center, and VA protected the enzyme from H2O2-dependent inactivation. The HSP-FeP path transformed PPN through single electron transfer or H abstraction mechanisms. In addition, hydroxyl radicals generated in the LiP/H2O2 system were involved in the hydroxylation of the PPN intermediates. Possible degradation pathways were deduced using these degradation mechanisms and mass-spectrometry analysis. The multipath degradation mechanism endowed LiP with a remarkable capacity for removing various recalcitrant pollutants in environmental remediation.

Synthesis and application of a novel polyurethane nanoemulsion bearing coumarin derivative as a "turn-on" fluorescence sensor toward Hg2.

A novel polyurethane (PU-co-HCCA) nanoemulsion bearing coumarin derivative (HCCA) was synthesized as a "turn-on" fluorescent probe and used to modify filter paper, and its sensing properties were investigated. Results showed that PU-co-HCCA nanoemulsion exhibited high selectivity and excellent sensitivity toward Hg2+ over other metal ions, and possessed excellent fluorescence quantum yields of 0.976, ppb-levels detection limits of 1.61 ppb and large Stokes shifts of 101 nm. Meanwhile, as an application example of as-prepared PU-co-HCCA nanoemulsion, a Hg2+ test paper was prepared by modifying filter paper with PU-co-HCCA nanoemulsion, and results indicated that the test paper is portable and convenient and has a wide working pH range. We believe that the PU-co-HCCA nanoemulsion and the modified filter paper can provide a new design principle for the application of fluorescence sensors for metal ions including Hg2+.

Thermal and UV light adaptive polyurethane elastomers for photolithography-transfer printing of flexible circuits.

Flexible polymers are widely used in the fields of wearable devices, soft robots, sensors, and other flexible electronics. Combining high strength and elasticity, electrical conductivity, self-healability, and surface tunable properties in one material becomes a challenge for designing polymeric materials for these applications, especially in flexible electronics. Herein, we propose a "two birds with one stone" strategy to synthesize thermal and UV light adaptive polyurethane elastomers with high-strength, self-healable, surface-modifiable and patternable functions for photolithography-transfer printing flexible circuits. The "stone", dihydroxybenzophenone, plays two roles in the synthesized polyurethanes as both a dynamic covalent bond and a UV-sensitive unit. On one hand, the phenolic group reacts with isocyanate to form a dynamic covalent phenol-carbamate bond, making the polymer self-healable, processable, and surface-embeddable with conductive fillers utilizing dynamic network rearrangement. On the other hand, the benzophenone group acts as a UV-sensitive unit to graft other functional groups to the polymer surface or self-crosslink on the surface under UV irradiation. Based on the dynamic covalent network and UV self-crosslinking properties, self-healable patterned flexible circuits can be obtained by photolithography-transfer printing. The flexible circuits prepared by loading silver nanowires on the dynamically crosslinked polyurethane substrate show little change of electric resistance when stretched up to 125% and can withstand thousands of stretching cycles.

Potential Protective Effect of Riboflavin Against Pathological Changes in the Main Organs of Male Mice Induced by Fluoride Exposure.

Long-term exposure to excessive fluorine could cause damage to various tissues and organs in human and animals. However, there is no effective antidote to prevent and cure fluorosis except for avoiding fluoride intake. As an essential nutrient, riboflavin (VB2) has been identified to relieve oxidative stress and inflammation in animal tissues caused by other toxic substances, whether it can alleviate the damage caused by fluoride is unknown. For this, 32 ICR male mice were allocated to four groups of eight each. They were treated with 0 (distilled water), 100 mg/L sodium fluoride (NaF), 40 mg/L VB2, and their combination (100 mg/L NaF plus 40 mg/L VB2) via the drinking water for 90 consecutive days, respectively. The content of bone fluoride and the histomorphology of the main organs including liver, kidney, cerebral cortex, epididymis, small intestine, and colon were evaluated and pathologically scored. The results found that fluoride caused the pathological changes in liver, kidney, cerebral cortex, epididymis, small intestine, and colon at varying degrees, while riboflavin supplementation reduced significantly the accumulation of fluoride in bone, alleviated the morphological damage to cerebral cortex, epididymis, ileum, and colon. This study provides new clues for deeply exploring the mechanism of riboflavin intervention in fluorosis.

Effects of nanopolystyrene addition on nitrogen fertilizer fate, gaseous loss of N from the soil, and soil microbial community composition.

Nanoplastics and microplastics are the degradation products of plastics waste and have become a dominant pollutant in the environment. However, little is known about the ecological impacts of nanoplastic particles in the agroecosystem. We conducted a mesocosm experiment to examine nanopolystyrene effects on fertilizer nitrogen (N) fate, N gaseous losses and soil microbial communities using Chinese cabbage (Brassica Campestris ssp.) as the model plant. The two-factorial experiment was designed as the addition of 15N-labeled urea exposed without and with ~50 nm nanopolystyrene (0, 0.05%, and 0.1%). Nanopolystyrene addition had a detectable effect on soil mineral N content. The 15N uptake of plants was reduced in aboveground biomass but enhanced in roots with increasing nanopolystyrene concentration. Nanopolystyrene addition decreased soil nitrous oxide and ammonia emissions by 27% and 37%, respectively. Nanopolystyrene addition consistently reduced the abundance of ammonia oxidizer genes but showed contrasting effects on denitrifying genes. Metagenomic sequencing data revealed no significant effects of nanopolystyrene on the N-cycle pathway, while it significantly altered the composition of bacterial and fungal communities. This study provided the first insights into the nanopolystyrene induced linkage of root growth with more root N uptake and less gaseous N losses and the associated changes in the microbial community.

In vitro and in vivo evaluation of liposomes modified with polypeptides and red cell membrane as a novel drug delivery system for myocardium targeting.

Ischemic cardiac disease (ICD) is a cardiovascular disease with high morbidity and mortality. In this study, a novel myocardial targeted drug delivery system was developed represented by co-modified liposomes consisting of red cell membrane (RCM), and the peptides TAT and PCM. Liposomes were prepared using a membrane dispersion-ultrasonic method; the prepared 1% TAT and 3% PCM micelles were mixed with liposomes and under overnight stirring to form polypeptid-modified liposomes. RCM was isolated from mice blood, and the mechanical force facilitated RCM adhesion to the lipid bilayer. The characteristics of liposomes such as the morphology, particle size, zeta-potential, and RCM-conjugation to lipsomes were evaluated. Uptake efficiency and cellular toxicity of liposomes were evaluated in vitro on myocardial cells (MCs). As regard the experiments in vivo, liposomes were intravenously injected into mice, and the blood and organs were collectedat different times to analyze the pharmacokinetics profile of liposomes. The cellular uptake and intracellular distribution of liposomes of different composition into MCs demonstrated that RCM-modified liposomes had the best delivery capability. The pharmacokinetics study further demonstrated that RCM-modified liposomes had prolonged mean residence time (MRT) and more accumulation in the heart. This study indicated that RCM can be used to modify liposomes in combination with polypeptides, because such modification increases the myocardial targeting of liposomes. Therefore, this system constructed in this study might be a potentially effective myocardial drug delivery system.

Green construction of Fe3O4@GC submicrocubes for highly sensitive magnetic dispersive solid-phase extraction of five phthalate esters in beverages and plastic bottles.

A well-designed core-shelled Fe3O4@graphitic carbon (Fe3O4@GC) submicrocube was in situ constructed in a simple, relatively green and eco-friendly ways basing on one-step pyrolysis of low-cost waste napkins-coated Fe2O3 submicrocubes. The Fe3O4@GC submicrocubes showed unique architectures where in situ generated thin graphitic carbon layer wrapped on the surface of Fe3O4, resulting in excellent affinity to five phthalate esters (PAEs), good reusability and rapid magnetic separation, therefore were employed as magnetic dispersive solid-phase extraction material combined with HPLC to simultaneously detect five trace PAEs in beverages and plastic bottles. Under optimized conditions, recoveries (80.0%-112.8%), precision (RSDs ≤ 8.8%), and limits of detection (LODs) for beverages (0.09-0.28 µg L-1) and plastic bottles (0.01-0.03 µg g-1) were obtained. This work not only establishes an effective method for simultaneous determination of five PAEs, but also opens up a new strategy to design/construct magnetic graphitic carbon-encapsulated core-shell materials using low-cost/recyclable napkins as carbon source.

The dosage effects of dexamethasone on osteogenic activity andbiocompatibility of poly(lactic-co-glycolic acid)/hydroxyapatite nanofibers.

Poly(lactic-co-glycolic acid) (PLGA) based biomaterials have many advantages and potential applications in bone tissue engineering. Whereas, a significant problem which could not be ignored was that the acidic by-products generated during its degradation induced severe inflammatory reactions and negatively regulated bone regeneration. In this research, feasibility of using dexamethasone (Dex) to improve the biocompatibility of PLGA is investigated in detail. Hereby, various contents of PLGA/hydroxyapatite (PH) nanofibers loaded with Dex were synthesized by electrospinning technique. It was shown that 0.5% (wt) Dex in PH scaffolds was the minimum content which was required for anti-inflammatory effect. Admittedly, Dex to some extent had cytotoxic effect on osteoblasts and an inhibitory effect on ALP activity in this study; nevertheless, the relatively low Dex (<2% [wt]) had no inhibitory effects on osteoblasts maturation and mineralization. By this token, Dex is a good candidate for improving biocompatibility of PLGA based biomaterials. Moreover, the cytotoxic effects of Dex should be concerned. This study will provide a rationale for optimizing biocompatibility of PLGA based biomaterials by using Dex.

Hierarchical structured and programmed vehicles deliver drugs locally to inflamed sites of intestine.

Orally administrable drug delivery vehicles are developed to manage incurable inflammatory bowel disease (IBD), however, their therapeutic outcomes are compromised by the side effects of systemic drug exposure. Herein, we use hyaluronic acid functionalized porous silicon nanoparticle to bridge enzyme-responsive hydrogel and pH-responsive polymer, generating a hierarchical structured (nano-in-nano-in-micro) vehicle with programmed properties to fully and sequentially overcome the multiple obstacles for efficiently delivering drugs locally to inflamed sites of intestine. After oral administration, the pH-responsive matrix protects the embedded hybrid nanoparticles containing drug loaded hydrogels against the spatially variable physiological environments of the gastrointestinal tract until they reach the inflamed sites of intestine, preventing premature drug release. The negatively charged hybrid nanoparticles selectively target the inflamed sites of intestine, and gradually release drug in response to the microenvironment of inflamed intestine. Overall, the developed hierarchical structured and programmed vehicles load, protect, transport and release drugs locally to inflamed sites of intestine, contributing to superior therapeutic outcomes. Such strategy could also inspire the development of numerous hierarchical structured vehicles by other porous nanoparticles and stimuli-responsive materials for the local delivery of various drugs to treat plenty of inflammatory gastrointestinal diseases, including IBD, gastrointestinal cancers and viral infections.