Self-Assembled Sandwich-like MXene-Derived Composites as Highly Efficient and Sustainable Catalysts for Wastewater Treatment.

Photocatalysts play an increasingly important role in environmental remediation polluted by industrial wastewater. However, the preparation of adsorbents and catalysts with high activity by simple and easy methods is still a great challenge. Here, sandwich-like composite catalyst Cu2O/TiO2/Ti3C2 was prepared by an easily available solvent reduction measure for the highly efficient catalytic nitro compounds. In particular, sandwich-like composite catalyst Cu2O/TiO2/Ti3C2 exhibits excellent catalysis for 2-nitroaniline (2-NA) and 4-nitrophenol (4-NP), and its pseudo-first-order reaction rate constants (k) are 0.163 and 0.114 min-1, respectively. Interestingly, even after eight consecutive cycles of catalytic experiments, the conversion rates of catalytic 2-NA and 4-NP are still greater than 95 and 92%, respectively, demonstrating that the obtained catalyst has excellent catalytic capability and a high reutilization rate. The excellent catalytic performances of Cu2O/TiO2/Ti3C2 can be attributed to the fact that Ti3C2 provides a greater reaction site for the formation of Cu2O and reduces the aggregation during the formation of Cu2O by in situ synthesis. Therefore, ternary composite catalyst Cu2O/TiO2/Ti3C2 prepared by solvent reduction not only supplies a technical method for the catalytic reaction of MXene-based material but also lays the foundation for the development of new photocatalysts.

Chemical Vapor Deposition-Assisted Fabrication of Self-Assembled Co/MnO@C Composite Nanofibers as Advanced Anode Materials for High-Capacity Li-Ion Batteries.

Constructing the nanostructure of transition metal oxides for high energy density lithium-ion batteries has been widely studied recently. Prompted by the idea that the transition metal can serve as a catalyzer influence on the reversibility of solid-electrolyte interphase films, Co/MnO@C composite nanofibers were designed by electrospinning and chemical vapor deposition methods. The Co/MnO@C electrode showed superior electrochemical performance with a large capacity increase for the first 400 cycles and a high rate performance of 1345 mA h g-1 at 1000 mA g-1. There was no obvious decay of capacity over the whole 1000 cycles, demonstrating the excellent cycling stability of the samples. The new design and synthesis of the anodic materials may offer a prototype for high-performance and strong-stability batteries.

Preparation and High Photocurrent Generation Enhancement of Self-Assembled Layered Double Hydroxide-Based Composite Dye Films.

Understanding photocurrent conversion of layered double hydroxide (LDH) materials will be a key step in the future application of these materials to light-capturing molecular devices. In the present study, ultrathin nickel-iron layered double hydroxide/dye (NF-LDH/dye) Langmuir-Blodgett (LB) semiconductor films were prepared using an LB device and deposited on an indium tin oxide (ITO) substrate as a photoanode. The photoelectric conversion efficiency of the prepared LB semiconductor film materials was tested. A comparative experiment was performed to effectively explore the photoelectric conversion performances of the LB semiconductor film materials. Specifically, the NF-LDH cast film electrode, the dye cast film electrode, and an ultrathin composite LB film electrode were used as typical samples to explore photoelectric conversion performances. The electrochemical workstation was used to study the photocurrent density, linear scanning voltammetry curve, and electrochemical impedance spectroscopy of LB film electrodes with different layers. The results show that the film electrode cast by LDH alone or dye alone produces weak photocurrent. The photoelectric conversion efficiency of the LB film electrode is enhanced due to the different dyes' molecular structures and/or aggregations on the surface of LDH with various morphological patterns. The combined NF-LDH/dye composite LB film photoelectrode can generate a photocurrent that is 2-5 times stronger than the raw material, and the stable use efficiency is more than 92%. Present obtained composite LB films demonstrated a uniform morphology and good photoelectric conversion ability. This work provides a useful reference for the field of LDH semiconductor optoelectronic devices and solar cells.

Facile preparation of self-assembled hydrogels constructed from poly-cyclodextrin and poly-adamantane as highly selective adsorbents for wastewater treatment.

Self-assembled hydrogel materials constructed from cyclodextrin polymer (P-CD)/adamantane-modified poly acrylic acid (PAA-Ad) were designed and prepared via host-guest interactions. It was observed that the prepared supramolecular hydrogels had an interconnected three-dimensional porous network. In addition, the obtained hydrogels showed a recovery performance and it was confirmed that the host-guest interactions between ß-cyclodextrin and adamantane were the main driving force for the formation of the hydrogels. The mechanical properties of the hydrogels could be adjusted by varying the concentrations of PAA-Ad. In particular, the prepared supramolecular hydrogels exhibited superior performances in water purification. The results demonstrated that the hydrogels possessed different mechanisms in the adsorption of the four typical poisonous organic dye molecules used, including bisphenol A (BPA), 4-aminoazobenzene (N-Azo), methylene blue (MB), and rhodamine B (RhB). The hydrogels mainly adsorbed N-Azo by host-guest interaction and adsorbed BPA by host-guest interaction and hydrogen bond synergy. They also adsorbed MB and RhB by hydrogen bonding and electrostatic interaction.

Facile preparation of a self-assembled Artemia cyst shell-TiO2-MoS2 porous composite structure with highly efficient catalytic reduction of nitro compounds for wastewater treatment.

The catalytic reduction of nitro compounds is currently a hot research area, how to efficiently and stably degrade such toxic and harmful substances has become the research goal of many researchers. In this work, an Artemia cyst shell (ACS)-TiO2-MoS2 ternary porous structure was proposed and prepared as a catalyst for the reduction of 2-nitroaniline (2-NA) and 4-nitrophenol (4-NP). The ACS has a large number of porous structures, exhibits a good binding ability with TiO2 and MoS2, and provides a large number of active sites for the catalytic reduction process. The obtained composite material has a good reduction effect on 4-NP and 2-NA, with a good stability and recyclability, which is obviously higher than the reduction effect of ACS-TiO2 and MoS2 under the same conditions. This work provides ideas for the design of porous catalytic materials.

Facile synthesis of self-assembled carbon nanotubes/dye composite films for sensitive electrochemical determination of Cd(II) ions.

A new type of voltammetric sensor material has been fabricated via a facile self-assembled method. A modified glassy carbon electrode (GCE) by phenylsulfonic groups grafted multi-walled carbon nanotubes (CNT-SO3H) with dye molecules via Langmuir-Blodgett (LB) assembling (CNT-SO3H/dye-LB/GCE) were prepared for detecting trace levels of cadmium (Cd2+) ions by square wave anodic stripping voltammetry. The synergy effect between CNT-SO3H and dye as well as orderly aggregates in composite LB films contributed to greatly enhancing the determination performance. Under selected conditions, voltammetric response of the fabricated electrochemical sensor in 0.1 M acetate buffer solution containing Bi3+ ions for Cd2+ ions was linear with its concentration in the range 0.1 to 1.2 µM, with a detection limit of 0.08 µM. In addition, the preparation process of self-assembled composite film modified electrodes was simple, non-toxic, exhibiting higher sensitivity and potential application prospects in aspects of heavy metal ions detection and environmental analysis.

Genetic variation, population structure and linkage disequilibrium in Switchgrass with ISSR, SCoT and EST-SSR markers.

BACKGROUND: To evaluate genetic variation, population structure, and the extent of linkage disequilibrium (LD), 134 switchgrass (Panicum virgatum L.) samples were analyzed with 51 markers, including 16 ISSRs, 20 SCoTs, and 15 EST-SSRs. RESULTS: In this study, a high level of genetic variation was observed in the switchgrass samples and they had an average Nei's gene diversity index (H) of 0.311. A total of 793 bands were obtained, of which 708 (89.28 %) were polymorphic. Using a parameter marker index (MI), the efficiency of the three types of markers (ISSR, SCoT, and EST-SSR) in the study were compared and we found that SCoT had a higher marker efficiency than the other two markers. The 134 switchgrass samples could be divided into two sub-populations based on STRUCTURE, UPGMA clustering, and principal coordinate analyses (PCA), and upland and lowland ecotypes could be separated by UPGMA clustering and PCA analyses. Linkage disequilibrium analysis revealed an average r2 of 0.035 across all 51 markers, indicating a trend of higher LD in sub-population 2 than that in sub-population 1 (P < 0.01). CONCLUSIONS: The population structure revealed in this study will guide the design of future association studies using these switchgrass samples.

Bovine serum albumin in saliva mediates grazing response in Leymus chinensis revealed by RNA sequencing.

BACKGROUND: Sheepgrass (Leymus chinensis) is an important perennial forage grass across the Eurasian Steppe and is adaptable to various environmental conditions, but little is known about its molecular mechanism responding to grazing and BSA deposition. Because it has a large genome, RNA sequencing is expensive and impractical except for the next-generation sequencing (NGS) technology. RESULTS: In this study, NGS technology was employed to characterize de novo the transcriptome of sheepgrass after defoliation and grazing treatments and to identify differentially expressed genes (DEGs) responding to grazing and BSA deposition. We assembled more than 47 M high-quality reads into 120,426 contigs from seven sequenced libraries. Based on the assembled transcriptome, we detected 2,002 DEGs responding to BSA deposition during grazing. Enrichment analysis of Gene ontology (GO), EuKaryotic Orthologous Groups (KOG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed that the effects of grazing and BSA deposition involved more apoptosis and cell oxidative changes compared to defoliation. Analysis of DNA fragments, cell oxidative factors and the lengths of leaf scars after grazing provided physiological and morphological evidence that BSA deposition during grazing alters the oxidative and apoptotic status of cells. CONCLUSIONS: This research greatly enriches sheepgrass transcriptome resources and grazing-stress-related genes, helping us to better understand the molecular mechanism of grazing in sheepgrass. The grazing-stress-related genes and pathways will be a valuable resource for further gene-phenotype studies.

Recent progress in hydrogels combined with phototherapy for bacterial infection: A review.

Phototherapy has become one of the most effective antibacterial methods due to its associated lack of drug resistance and its good antibacterial effect. For the purpose of avoiding the aggregation and premature release of photosensitive/photothermal agents during phototherapy, they can be mixed into three-dimensional hydrogels. The combination of hydrogels and phototherapy combines the merits of both hydrogels and phototherapy, overcomes the disadvantages of traditional antibacterial methodologies, and has broad application prospects. This review presents recent advancements in phototherapeutic antibacterial hydrogels including photodynamic antibacterial hydrogels, photothermal antibacterial hydrogels, photodynamic and photothermal synergistic antibacterial hydrogels, and other synergistic antibacterial hydrogels involving phototherapy.

Recent Progress in the Applications of Langmuir-Blodgett Film Technology.

Langmuir-Blodgett (LB) film technology is an advanced technique for the preparation of ordered molecular ultra-thin films at the molecular level, which transfers a single layer of film from the air/water interface to a solid substrate for the controlled assembly of molecules. LB technology has continually evolved over the past century, revealing its potential applications across diverse fields. In this study, the latest research progress of LB film technology is reviewed, with emphasis on its latest applications in gas sensors, electrochemical devices, and bionic films. Additionally, this review evaluates the strengths and weaknesses of LB technology in the application processes and discusses the promising prospects for future application of LB technology.

Electrospinning Silk-Fibroin-Based Fibrous Membranes with AgNPs for Antimicrobial Application.

Silk fibroin (SF) has excellent biocompatibility and is one of the most commonly used polymer materials. However, SF fibers have serious drawbacks as antibacterial materials due to their lack of stability and bacterial resistance. Therefore, it is of paramount significance to enhance the stability and bolster the bacterial resistance of SF fibers. In this study, SF fibers were fabricated and loaded with Ag nanoparticles (AgNPs) to improve the antimicrobial properties of the fibers. The impact of reduction conditions on the size of AgNPs was also investigated. In an antibacterial test, the fibers that were prepared exhibited over 98% bacterial resistance against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Therefore, as an efficient antibacterial material, these fibers are expected to become a candidate material in medical and textile fields. This study offers a novel approach for the utilization of SF fibers in the realm of antibacterial applications.

Construction of cellulose acetate-based composite nanofiber films with effective antibacterial and filtration properties.

In recent years, the safety of public health has attracted more and more attention. In order to avoid the spread of bacteria and reduce the diseases caused by their invasion of the human body, novel filtration and antibacterial materials have attracted more and more attention. In this work, the antibacterial agents silver nanoparticles (AgNPs) and cetylpyridine bromide (CPB) were introduced into a cellulose acetate (CA) nanofiber film by electrospinning technology to prepare CA-based composite films with good antibacterial and filtration properties. The results of the antibacterial test of the composite nanofiber films showed that AgNPs and CPB had synergistic antibacterial effects and exhibited good antibacterial properties against a variety of bacteria. In addition, in vitro cytotoxicity, skin irritation and skin sensitization experiments proved that the CA/AgNPs, CA/CPB and CA/CPB/AgNPs films produced no skin irritation or sensitization in the short term. These are expected to become potential materials for the preparation of new antibacterial masks. This work provides a new idea for developing materials with good antibacterial properties for enhancing protection via filtration masks.

Transmissibility of hand, foot, and mouth disease in 97 counties of China.

Hand, foot, and mouth disease (HFMD) is a serious disease burden in the Asia-Pacific region, including China. This study calculated the transmissibility of HFMD at county levels in Jiangsu Province, China, analyzed the differences of transmissibility and explored the possible influencing factors of its transmissibility. We built a mathematical model for seasonal characteristics of HFMD, estimated the effective reproduction number (Reff), and compared the incidence rate and transmissibility in different counties using non-parametric tests, rapid cluster analysis and rank-sum ratio in 97 counties in Jiangsu Province from 2015 to 2020. The average daily incidence rate was between 0 and 4 per 100,000 people in Jiangsu Province from 2015-2020. The Quartile of Reff in Jiangsu Province from 2015 to 2020 was 1.54 (0.49, 2.50). Rugao District and Jianhu District had the highest transmissibility according to the rank-sum ratio. Reff generally decreased in 2017 and increased in 2018 in most counties, and the median level of Reff was the lowest in 2017 (P < 0.05). The transmissibility was different in 97 counties in Jiangsu Province. The reasons for the differences may be related to the climate, demographic characteristics, virus subtypes, vaccination, hygiene and other infectious diseases.

Study on the interaction between different pathogens of Hand, foot and mouth disease in five regions of China.

Objectives: This study aims to explore the interaction of different pathogens in Hand, foot and mouth disease (HFMD) by using a mathematical epidemiological model and the reported data in five regions of China. Methods: A cross-regional dataset of reported HFMD cases was built from four provinces (Fujian Province, Jiangsu province, Hunan Province, and Jilin Province) and one municipality (Chongqing Municipality) in China. The subtypes of the pathogens of HFMD, including Coxsackievirus A16 (CV-A16), enteroviruses A71 (EV-A71), and other enteroviruses (Others), were included in the data. A mathematical model was developed to fit the data. The effective reproduction number (R eff ) was calculated to quantify the transmissibility of the pathogens. Results: In total, 3,336,482 HFMD cases were collected in the five regions. In Fujian Province, the R eff between CV-A16 and EV-A71&CV-A16, and between CV-A16 and CV-A16&Others showed statistically significant differences (P < 0.05). In Jiangsu Province, there was a significant difference in R eff (P < 0.05) between the CV-A16 and Total. In Hunan Province, the R eff between CV-A16 and EV-A71&CV-A16, between CV-A16 and Total were significant (P < 0.05). In Chongqing Municipality, we found significant differences of the R eff (P < 0.05) between CV-A16 and CV-A16&Others, and between Others and CV-A16&Others. In Jilin Province, significant differences of the R eff (P < 0.05) were found between EV-A71 and Total, and between Others and Total. Conclusion: The major pathogens of HFMD have changed annually, and the incidence of HFMD caused by others and CV-A16 has surpassed that of EV-A71 in recent years. Cross-regional differences were observed in the interactions between the pathogens.

Facile Preparation of Self-Assembled Chitosan-Based POSS-CNTs-CS Composite as Highly Efficient Dye Absorbent for Wastewater Treatment.

In this work, a new nanocomposite based on octa-amino polyhedral oligomeric silsesquioxanes (POSS), carbon nanotubes (CNTs), and chitosan (CS) was synthesized and used for wastewater treatment. The properties and morphologies of the prepared composite were analyzed by X-ray diffraction, scanning electron microscopy, transmission electron microscope, thermogravimetric, and atomic force microscopy. The results showed that POSS, CNTs, and CS formed a stable composite through intermolecular forces, and the modification of CS by POSS and CNTs improved its stability. In addition, the obtained composite showed good adsorption performance for the degradation of methyl orange and Congo red dyes. The pseudo-first-order model and pseudo-second-order model were used to analyze the adsorption data, and the results showed that the adsorption process conforms to the kinetic model. Moreover, the maximum adsorption capacity of the composite to methyl orange and Congo red reached 63.23 and 314.97 mg/g, respectively. This work provides new ideas for the preparation of self-assembled multi-composite and their potential applications in wastewater treatment.

Self-Assembled Black Phosphorus-Based Composite Langmuir-Blodgett Films with an Enhanced Photocurrent Generation Capability and Surface-Enhanced Raman Scattering Properties.

In this work, Langmuir-Blodgett (LB) composite thin films were successfully prepared using black phosphorus nanosheets (BPNS) and dye molecules. Black phosphorus (BP) was first exfoliated in isopropanol solution to form BPNS, and then, BPNS were modified with 4-azidobenzoic acid (Az-BPNS) to improve their stability. The characterization results showed that the synthesized Az-BPNS-dye LB films have a uniform and ordered structure. In addition, the synthesized Az-BPNS-dye LB films exhibit excellent photoelectrochemical performance, and Az-BPNS-methylene blue (MB) produces higher photocurrent compared to Az-BPNS-Neutral red (NR) films. The current work shows an effective way to prepare functionalized BP-based materials and provide evidence for their application in optoelectronic devices.

Magnetic graphene oxide-containing chitosan­sodium alginate hydrogel beads for highly efficient and sustainable removal of cationic dyes.

Developing recyclable and efficient adsorbents for cationic dyes removal from wastewater is crucial for ensuring green ecology and drinking water safety. Herein, we demonstrated a novel magnetic gel bead adsorbent that was synthesized by employing graphene oxide (GO) modified Fe3O4 as magnetic nanoparticles doped sodium alginate (SA)/chitosan (CS) gel (SA/GO@Fe3O4/CS). The GO@Fe3O4 sample was prepared based on GO by the chemical co-precipitation method, which not only reduced the aggregation of Fe3O4 but also increases the specific surface area of the composite gel beads. The prepared gel beads were used to adsorb methylene blue (MB), neutral red (NR), and safranine T (ST). The experimental results showed that the adsorption capacity of SA/GO@Fe3O4/CS gel beads for MB, NR, and ST reached 21.325 mg/g, 44.654 mg/g and 44.313 mg/g. After five recycles, the removal rates could still reach more than 90% of the original, exhibiting a high recovery rate. Therefore, this paper provides a strategy for the preparation of high efficiency and recyclable cationic dye adsorbents with a large specific surface area.

Fabrication of CS/GA/RGO/Pd composite hydrogels for highly efficient catalytic reduction of organic pollutants.

In this study, natural polymer material chitosan (CS) and graphene oxide (GO) with large specific surface area were used to prepare a new CS/RGO-based composite hydrogel by using glutaraldehyde (GA) as cross-linking agent. In addition, a CS/GA/RGO/Pd composite hydrogel was prepared by loading palladium nanoparticles (Pd NPs). The morphologies and microstructures of the prepared hydrogels were characterized by SEM, TEM, XRD, TG, and BET. The catalytic performance of the CS/GA/RGO/Pd composite hydrogel was analyzed, and the experimental results showed that the CS/GA/RGO/Pd composite hydrogel had good catalytic performance for degradation of p-nitrophenol (4-NP) and o-nitroaniline (2-NA). Therefore, this study has potential application prospect in wastewater treatment and provides new information for composite hydrogel design.

Self-assembled functional components-doped conductive polypyrrole composite hydrogels with enhanced electrochemical performances.

A conductive hydrogel is a composite conductive material formed by combining a conductive polymer with a nanogel structure of a hydrogel. Conductive hydrogels not only have potential applications in supercapacitors, sensors, and modulators, they can also be synthesized by many methods, such as copolymerization, crosslinking, and grafting. In this work, we successfully prepared three conductive composite hydrogels by in situ polymerization, namely polypyrrole sodium alginate conductive hydrogel, ferric chloride-doped polypyrrole sodium alginate hydrogel and doped polypyrrole sodium alginate hydrogel with sodium dodecylbenzene sulfonate. In addition, a series of characterizations were performed for the three conductive hydrogels described above. The results show that the polypyrrole sodium alginate hydrogel doped with ferric chloride forms a nanofiber network with a more stable structure and better electrochemical performance.

Fabrication of Hydrogels via Host-Guest Polymers as Highly Efficient Organic Dye Adsorbents for Wastewater Treatment.

New self-assembled hydrogel materials of poly(vinyl alcohol)/cyclodextrin-modified poly(acrylic acid)/azobenzene-modified poly(acrylic acid) (PVA/PAA-CD/PAA-Azo) were successfully prepared via host-guest interactions and hydrogen bonds. The as-prepared hydrogel materials were characterized by various techniques, including Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, ultraviolet spectroscopy, and specific surface area tests. The prepared hydrogels with different concentrations of PVA exhibited different network structures. In addition, ultraviolet (UV) light irradiation and temperature change induce a gel-sol phase transition in the hydrogel materials. The obtained hydrogel materials could be used as good adsorbents for two model organic dye molecules, which was mainly due to electrostatic interactions between methylene blue/rhodamine B (MB/RhB) and the gels in the adsorption process. In particular, the adsorption processes of the as-prepared hydrogel materials conformed to the pseudo-first-order model with a high correlation coefficient, which indicates that gel has a potential application in the field of wastewater purification.