Al8 Cluster-Based Metal Halide Frameworks: Balancing Singlet-Triplet Excited States to Achieve White Light and Multicolor Luminescence.

Luminescent metal clusters have attracted great interest in current research; however, the design synthesis of Al clusters with color-tunable luminescence remains challenging. Herein, an [Al8 (OH)8 (NA)16 ] (Al8 , HNA = nicotinic acid) molecular cluster with dual luminescence properties of fluorescence and room-temperature phosphorescence (RTP) is synthesized by choosing HNA ligand as phosphor. Its prompt photoluminescence (PL) spectrum exhibits approximately white light emission at room temperature. Considering that halogen atoms can be used to regulate the RTP property by balancing the singlet and triplet excitons, different CdX2 (X- = Cl- , Br- , I- ) are introduced into the reactive system of the Al8 cluster, and three new Al8 cluster-based metal-organic frameworks, {[Al8 Cd3 Cl5 (OH)8 (NA)17 H2 O]·2HNA}n (CdCl2 -Al8 ), {[Al8 Cd4 Br7 (OH)8 (NA)16 CH3 CN]·NA·HNA}n (CdBr2 -Al8 ) and {[Al8 Cd8 I16 (OH)8 (NA)16 ]}n (CdI2 -Al8 ) are successfully obtained. They realize the color tunability from blue to yellow at room temperature. The origination of fluorescence and phosphorescence has also been illustrated by structure-property analysis and theoretical calculation. This work provides new insights into the design of multicolor luminescent metal cluster-based materials and develops advanced photo-functional materials for multicolor display, anti-counterfeiting, and encryption applications.

Recent Advances in Multidimensional (1D, 2D, and 3D) Composite Sensors Derived from MXene: Synthesis, Structure, Application, and Perspective.

With the advent of the era of intelligent manufacturing, sensors, with various detection objects, have set off a wave of enthusiasm and reached new heights in medical treatment, intelligent industry, daily life, and so on. MXene, as an emerging family of 2D transition metal carbides/nitrides, possesses impressive electrical conductivity, outstanding structural controllability, and satisfying universality with other substrates. Consequently, MXene-based sensors with various functions show a booming growth based on great research potential of MXene. To promote the orderly and efficient development of MXene application in sensors, and further accelerate market-scale application of ideal sensors, in this review, a full range research effort on current MXene-based sensors is summarized. Starting with various synthesis methods of the raw material MXene, a comprehensive summary work along with 1D, 2D, or 3D MXene-based sensors on most recent works is put forward, including the preparation method, characteristic structure, and potential sensing application of each type of MXene-based composite sensors. Ultimately, insights of the opportunities and challenges on the strength of the current reported MXene-based sensor are given.

Recycling of High-Value-Added Aramid Nanofibers from Waste Aramid Resources via a Feasible and Cost-Effective Approach.

High-performance aramid fibers are extensively applied in the civil and military fields. A great deal of waste aramid resources originating from the manufacturing process, spare parts, or end of life cycle are wrongly disposed (i.e., landfill, smash, fibrillation), causing a waste of valuable resources as well as severe environmental pollution. Although aramid nanofibers (ANFs) have recently been recently reported as one of the most promising building blocks due to their excellent properties, they suffer from an extremely high production expenditure, thereby greatly hindering their scale-up application. Herein, in this paper, from a resources-saving and cost-reductional perspective, we present a feasible top-down approach to recycle high value-added ANFs with an affordable cost from various waste aramid resources. The results indicate that although the reclaimed ANFs have a molecular weight reduction of 8.1% compared with the recycled aramid fibers, they still exhibit a molecular weight of 43.0 kg·mol-1 that represents the highest value compared to other methods. It is noteworthy that the fabrication cost of ANFs is significantly reduced (∼7 times) due to the reclamation of waste aramid fibers instead of the expensive virgin aramid fibers. The obtained ANFs show impressive tensile strength (149.2 MPa) and toughness (10.43 MJ·m-3), excellent thermal stabilities (Td of 542 °C), and a high specific surface area (65.2 m2·g-1), which endows them to be promising candidates for constructing advanced materials. Compared to the aramid pulp obtained by the traditional recycling method, ANFs show significant advantages in dimensional homogeneity, aspect ratio, dispersibility, film-forming property, and especially the excellent properties of the ANF film. In addition, the scale-up preparation of ANFs from the recycled waste aramid fibers is carried out, demonstrating it is highly economically viable. Therefore, this work provides a highly feasible and cost-effective recycle system to reclaim the waste aramid resources together with significantly reducing the preparation cost of ANFs.

Flexible, Robust, and Durable Aramid Fiber/CNT Composite Paper as a Multifunctional Sensor for Wearable Applications.

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly-m-phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.

Highly Compressible, Thermally Stable, Light-Weight, and Robust Aramid Nanofibers/Ti3AlC2 MXene Composite Aerogel for Sensitive Pressure Sensor.

Various wearable aerogel sensors are emerging for their light weight, fairly wide sensing range, and sensitive sensing ability. Aramid nanofibers (ANFs) as a kind of burgeoning building blocks realize multifunctional applications in diversified fields for their innate extinguished mechanical property and thermal stability. Limited by their high insulating property, in this work ANFs were designed to integrate with a 2D emerging MXene sheet with a distinct conductive property. Herein, we report an MXene/ANFs composite aerogel through a feasible controllable vacuum filtration followed by a freeze-drying process. Benefiting from the inerratic 3D hierarchical and "mortar-brick" porous structure with an ultralow density of 25 mg/cm3, MXene/ANFs aerogels are proved to possess high compressible resilience and appealing sensing performance up to 1000 times. Importantly, verified by a series of simulation experiments, the MXene/ANFs aerogel sensor shows a wide detection range (2.0-80.0% compression strain), sensitive sensing property (128 kPa-1), and ultralow detection limit (100 Pa), which still play a flexible role in detecting human light movement and even vigorous sports after undergoing ultrahigh devastating pressures (∼623 kPa). In addition, the MXene/ANFs aerogel sensor can withstand a harsh high temperature of 200 °C and shows excellent flame resistance. The MXene/ANFs aerogel with excellent integrated property, especially the highly sensitive sensing property and excellent thermal stability, presents great potential for a human behavior monitoring sensor and sensing under certain extreme conditions.

Timesaving, High-Efficiency Approaches To Fabricate Aramid Nanofibers.

Aramid nanofibers (ANFs) have become promising nanoscale building blocks due to their extraordinary performance. However, there are numerous challenges related to the preparation of ANFs, such as the lengthy preparation cycle (7-10 days), low preparation concentration (0.2 wt %), and high difficulty in quantitatively judging the end point of the deprotonation reaction. Herein, we report three time-saving and high-efficiency strategies (fibrillation, ultrasonication, and proton donor-assisted deprotonation) to prepare ANFs with excellent performance. The fiber micromorphology during the deprotonation and protonation recovery processes was first investigated. Then the end point of the deprotonation reaction was detected by Raman spectra and the cationic demand of the ANF/DMSO system. Finally, the size, preparation cycle, and performance of the corresponding ANFs and ANF films fabricated by different approaches were investigated in detail. The results showed that proton donor-assisted deprotonation significantly shortened the traditional preparation cycle from 7 days to 4 h, and is the most efficient method reported thus far. It is noteworthy that a high concentration of ANFs (4.0 wt %) could also be achieved within 12 h. Interestingly, the fabricated ANFs exhibit rigid morphology and a small diameter with a narrow size distribution (10.7 ± 1.0 nm). The resultant ANF film displays desired characteristics of high strength and toughness. The work offers a timesaving, feasible and effective strategy to realize the large-scale production for ANFs, which will facilitate the application of ANFs in the production of advanced nanomaterials.

Comparative study of aramid nanofiber (ANF) and cellulose nanofiber (CNF).

Cellulose nanofiber (CNF) has faced challenges toward advanced applications due to the poor water resistance, wet strength, and poor thermal stability. The fabrication methods, morphologies and dispersibility between CNF and aramid nanofiber (ANF) were compared. Then the mechanical strength, especially the retention of wet strength (RWS), optical property, UV shielding, wettability and thermal stability of CNF and ANF nanopapers were further investigated. The results show that ANF and ANF nanopaper have significant advantages in dispersibility, water resistance, wet strength, thermal stability and UV-blocking ability over the CNF and CNF nanopaper. Especially the RWS of ANF nanopaper reached ˜82.5%, which notably exceeded the CNF nanopaper of 1.1%. This work demonstrates that the ANF could be an ideal alternative to CNF for advanced nanocomposites. Transparent, flexible, ultra-strong ANF nanopaper with favorable water resistance and wet strength, as well as good UV-blocking property shows great potential in variety of advanced applications.

Earthworms as agents for ecotoxicity in roxarsone-contaminated soil ecosystem: a modeling study of ultrastructure and proteomics.

Contamination of roxarsone has been recognized as a potential environmental hazard. In this study, Eisenia fetida samples were collected after roxarsone exposures to analyze their intestinal epithelium ultrastructure, expression levels of stress-related genes, and proteomics. Our results showed that mitochondria and endoplasmic reticulum in roxarsone-treated earthworms demonstrated variety of damages. Furthermore, 149 proteins were displayed in 2-DE, and 36 of them were identified by MALDI-TOF/TOF-MS. Those identified proteins are involved in several important processes including cell immunity, cell stress responses, and cell genetic behaviors. Our study demonstrates the toxicity responses of earthworms toward arsenic-based animal drug roxarsone with practical usefulness and demonstrates a proteomic profile change that may be critical for the roxarsone stress survival mechanisms of E. fetida. Graphical Abstract Inspiration of this referred to the form of Fig. 4 in the article "Proteomic analysis of a high aluminum tolerant yeast Rhodotorula taiwanensis RS1 in response to aluminum stress" of Chao, W et al.

Selective pressure of antibiotics on ARGs and bacterial communities in manure-polluted freshwater-sediment microcosms.

The aim of this study was to investigate selective pressure of antibiotics on antibiotic resistance genes (ARGs) and bacterial communities in manure-polluted aquatic environment. Three treatment groups were set up in freshwater-sediment microcosms: tetracyclines group, sulfonamides group and fluoroquinolones group. Sediment and water samples were collected on day 14 after treatment. Antibiotic concentrations, ARGs abundances and bacterial community composition were analyzed. Antibiotic concentrations were determined by ultra-performance liquid chromatography-electrospray tandem mass spectrometry. ARGs abundances were quantified by real time quantitative PCR. Bacterial community composition was analyzed based on amplicon sequencing. Of the three classes of antibiotics analyzed in the treatment groups, accumulation amounts were tetracyclines> fluoroquinolone> sulfonamides in the sediment samples, while they were sulfonamides> fluoroquinolone> tetracyclines in the water samples. In the treatment groups, the relative abundances of some tet resistance genes [tet(W) and tet(X)] and plasmid-mediated quinolone resistance (PMQR) genes [oqx(B) and aac(6')-Ib] in sediment samples were significantly higher than those in the paired water samples. Tetracyclines significantly selected the bacterial classes including Gammaproteobacteria, Clostridia, and the genera including Salmonella, Escherichia/Shigella, Clostridium, Stenotrophomonas in sediment samples. The significant selection on bacterial communities posed by sulfonamides and fluoroquinolones was also observed. The results indicated that sediment may supply an ideal setting for maintenance and persistence of tet resistance genes [tet(W) and tet(X)] and PMQR genes [oqx(B) and aac(6')-Ib] under antibiotic pollution. The results also highlighted that antibiotics significantly selected specific bacterial communities including the taxa associated with opportunistic pathogens.

Antibiotics, Antibiotic Resistance Genes, and Bacterial Community Composition in Fresh Water Aquaculture Environment in China.

Environmental antibiotic resistance has drawn increasing attention due to its great threat to human health. In this study, we investigated concentrations of antibiotics (tetracyclines, sulfonamides and (fluoro)quinolones) and abundances of antibiotic resistance genes (ARGs), including tetracycline resistance genes, sulfonamide resistance genes, and plasmid-mediated quinolone resistance genes, and analyzed bacterial community composition in aquaculture environment in Guangdong, China. The concentrations of sulfametoxydiazine, sulfamethazine, sulfamethoxazole, oxytetracycline, chlorotetracycline, doxycycline, ciprofloxacin, norfloxacin, and enrofloxacin were as high as 446 µg kg(-1) and 98.6 ng L(-1) in sediment and water samples, respectively. The relative abundances (ARG copies/16S ribosomal RNA (rRNA) gene copies) of ARGs (sul1, sul2, sul3, tetM, tetO, tetW, tetS, tetQ, tetX, tetB/P, qepA, oqxA, oqxB, aac(6')-Ib, and qnrS) were as high as 2.8 × 10(-2). The dominant phyla were Proteobacteria, Bacteroidetes, and Firmicutes in sediment samples and Proteobacteria, Actinobacteria and Bacteroidetes in water samples. The genera associated with pathogens were also observed, such as Acinetobacter, Arcobacter, and Clostridium. This study comprehensively investigated antibiotics, ARGs, and bacterial community composition in aquaculture environment in China. The results indicated that fish ponds are reservoirs of ARGs and the presence of potential resistant and pathogen-associated taxonomic groups in fish ponds might imply the potential risk to human health.

Responses of plasmid-mediated quinolone resistance genes and bacterial taxa to (fluoro)quinolones-containing manure in arable soil.

The aim of the present study was to investigate the fate of plasmid-mediated quinolone resistance (PMQR) genes and the disturbance of soil bacterial communities posed by (fluoro)quinolones (FQNs)-containing manure in arable soil. Representative FQNs (enrofloxacin (ENR), ciprofloxacin (CIP) and norfloxacin (NOR)), PMQR genes (qepA, oqxA, oqxB, aac(6')-Ib-cr and qnrS) and bacterial communities in untreated soil, +manure and +manure+FQNs groups were analyzed using culture independent methods. The significantly higher abundance of oqxA, oqxB and aac(6')-Ib-cr, and significantly higher abundance of qnrS in +manure group than those in untreated soil disappeared at day 30 and day 60, respectively. All PMQR genes (oqxA, oqxB, aac(6')-Ib-cr and qnrS) dissipated 1.5-1.7 times faster in +manure group than those in +manure+FQNs group. The disturbance of soil bacterial communities posed by FQNs-containing manure was also found. The results indicated that significant effects of PMQR genes (oqxA, oqxB, aac(6')-Ib and qnrS) on arable soils introduced by manure disappeared 2 month after manure application. FQNs introduced by manure slowed down the dissipation of PMQR genes. The presence of high FQNs provided a selective advantage for species affiliated to the phylum including Acidobacteria, Verrucomicrobia and Planctomycetes while suppressing Proteobacteria and Actinobacteria.

Fate of metal resistance genes in arable soil after manure application in a microcosm study.

Manure application contributes to the spread and persistence of metal resistance genes (MRGs) in the environment. We investigated the fate of copper (Cu) and zinc (Zn) resistance genes (pcoA, pcoD and zntA) in arable soil after Cu/Zn-containing manure application. Manure with or without addition of metals (Cu/Zn) was added in a soil microcosm over 2 months. Soil samples were collected for analysis on day 0, 30 and 60. The abundances of all MRGs (pcoA, pcoD and zntA) in manure group were significantly higher than those in untreated soil and manure+metals groups. All MRGs dissipated 1.2-1.3 times faster in manure group (from -90 ± 8% to -93 ± 7%) than those in manure+metals group (from -68 ± 8% to -78 ± 5%). The results indicated that manure from healthy pigs contributed to the occurrence of metals (Cu/Zn) and MRGs (pcoA, pcoD and zntA) in arable soil. The significant effects of manure application on the accumulation of pcoA, pcoD and zntA lasted for 1-2 months. Cu/Zn can slow down the dissipation of pcoA, pcoD and zntA after manure application. This is the first report to investigate the fate of MRGs in soil after manure application.

Molecular and ultrastructural insights into the earthworm Eisenia fetida of the assessment of ecotoxicity during colistin exposure.

Colistin is a peptide antibiotic widely used as a feed additive in animal farming, especially in poultry and swine production, for treatment and prevention of gram-negative bacterial infections, as well as for growth promotion use. When orally ingested, colistin is poorly absorbed and is eliminated almost unaltered by the enteric canal into the environment. Thus, risk of environmental toxicity cannot be ignored. In the present study, we examined the effects of colistin on Heath Shock Protein (HSP) 70, metallothionein (MT) gene expressions, and the ultrastructure of intestinal cells, following treatment of the soil indicator earthworm Eisenia fetida with 10, 20, and 100 mg/kg colistin for 7, 14, and 21 days. The results showed that, compared with the control, the expressions of HSP70 and MT genes changed significantly. Colistin caused up-regulations of HSP70's expression while inhibited the expression of MT gene. In addition, most mitochondria and endoplasmic reticulum were damaged in the group treated with high concentration. The investigation of gene expressions of HSP70 and MT, as well as pathological alterations in the intestinal cells, may provide important information in terms of ecotoxicity of colistin and can be used as early warning system.

Ecotoxicological effects of a veterinary food additive, copper sulphate, on antioxidant enzymes and mRNA expression in earthworms.

The present study was aimed to investigate the effect of the veterinary food additive copper sulphate (CuSO4) on the eco-toxicological responses of earthworms Eisenia fetida (E. fetida). The following biomarkers were measured: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) activities. Gene expression analyses such as metallothionein (MT) and heat shock protein 70 (Hsp70) were also examined. A time-dependent increase of CAT activity was found at 400 mg/kg and SOD activity at 200 and 400 mg/kg. The highest expression of Hsp70 (4.4-fold) was observed at day 15 at 400 mg/kg. Our results indicated that the measured antioxidant enzymes (except GST) had the ability to provide antioxidant defenses against the stressor; and compared to expression of MT, expression of Hsp70 could be more reliable molecular tools with predictive possibilities to monitor the eco-toxicity of stressors such as feed additive CuSO4.