Porous and graphitic carbon nanosheets with controllable structure for zinc-ion hybrid capacitor.

The imbalances of storage capacity and reaction kinetics between carbonaceous cathodes and zinc (Zn) anodes restrict the widespread application of Zn-ion hybrid capacitor (ZIHC). Structure optimization is a promising strategy for carbon materials to achieve sufficient Zn2+ storage sites and satisfied ion-electron kinetics. Herein, porous graphitic carbon nanosheets (PGCN) were simply synthesized using a K3[Fe(C2O4)3]- and urea-assisted foaming strategy with polyvinylpyrrolidone as carbon precursor, followed by activation and graphitization. Sufficient pores with well-matched pore sizes (0.80-1.94 nm) distributed across the carbon nanosheets can effectively shorten mass-transfer distance, promoting accessibility to active sites. A partially graphitic carbon structure with high graphitization degree can accelerate electron transfer. Furthermore, high nitrogen doping (7.2 at.%) provides additional Zn2+ storage sites to increase storage capacity. Consequently, a PGCN-based ZIHC has an exceptional specific capacity of 181 mAh g-1 at 0.5 A g-1, superb energy density of 145 Wh kg-1, and excellent cycling ability without capacity decay over 10,000 cycles. In addition, the flexible solid-state device assembled with PGCN exhibits excellent electrochemical performances even when bent at various angles. This study proposes a straightforward and economical strategy to construct porous graphitic carbon nanosheets with enhanced storage capacity and fast reaction kinetics for the high performance of ZIHC.

The Effect of Lactobacillus plantarum on the Fecal Microbiota, Short Chain Fatty Acids, Odorous Substances, and Blood Biochemical Indices of Cats.

Lactobacilli have played an important role in the gut health of pets. The aim of this research was to study the effects of isolated Lactobacilli (named L11) on the immune, nutrient metabolism, and gut health of cats. Twelve healthy adult cats were randomly assigned into two groups, the control group (CONTROL, n = 6, without any probiotics product) and the treatment group (probiotics, n = 6, L11 109 CFU/kg feed), while using the same dry diet. On day 28, blood and fecal samples were collected, and the blood biochemical indices, fecal microbiota, short-chain fatty acids (SCFAs), immunological parameters, and odorous substances were separately tested. The triglyceride of the blood was decreased after using L11 (p < 0.05), which could probably alleviate the occurrence of cat obesity to some extent. The sIgA of the feces was increased by 30.1% (p < 0.05), which could enhance the cat's immunity. The abundance of Bifidobacteria was increased after using L11 (p < 0.05), and the indole and 3-methylindole of the feces were both reduced compared with the control group; 3-methylindole was especially reduced by 67.3% (p < 0.05), which showed that L11 could also improve the intestinal state of cats. Therefore, this research shows that L11 could be a good choice to improve the gut health and immune functions of cats, and it is probably related to the lipid mechanism of cats.

Behavioral and molecular response of the insect parasitic nematode Steinernema carpocapsae to plant volatiles.

Entomopathogenic nematodes (EPNs) use the chemical cues emitted by insects and insect-damaged plants to locate their hosts. Steinernema carpocapsae, a species of EPN, is an established biocontrol agent used against insect pests. Despite its promising potential, the molecular mechanisms underlying its ability to detect plant volatiles remain poorly understood. In this study, we investigated the response of S. carpocapsae infective juveniles (IJs) to 8 different plant volatiles. Among these, carvone was found to be the most attractive volatile compound. To understand the molecular basis of the response of IJs to carvone, we used RNA-Seq technology to identify gene expression changes in response to carvone treatment. Transcriptome analysis revealed 721 differentially expressed genes (DEGs) between carvone-treated and control groups, with 403 genes being significantly upregulated and 318 genes downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the responsive DEGs to carvone attraction were mainly involved in locomotion, localization, behavior, response to stimulus, and olfactory transduction. We also identified four upregulated genes of chemoreceptor and response to stimulus that were involved in the response of IJs to carvone attraction. Our results provide insights into the potential transcriptional mechanisms underlying the response of S. carpocapsae to carvone, which can be utilized to develop environmentally friendly strategies for attracting EPNs.

Constructing a carboxyl-rich angstrom-level trap in a metal-organic framework for the selective capture of lithium.

A metal-organic-framework-based ion trap was designed via tailoring linker functionality as well as free -COOH density. The mixed-linker UiO-66-H2/H4 exhibits higher adsorption for Li+ ions than H4-free UiO-66-H2 because the H4 linker provides an additional -COOH group in the local region.

Investigating the Regulatory Mechanism of the Sesquiterpenol Nerolidol from a Plant on Juvenile Hormone-Related Genes in the Insect Spodoptera exigua.

Various plant species contain terpene secondary metabolites, which disrupt insect growth and development by affecting the activity of juvenile hormone-degrading enzymes, and the juvenile hormone (JH) titers maintained in insects. Nerolidol, a natural sesquiterpenol belonging to the terpenoid group, exhibits structural similarities to insect JHs. However, the impact of nerolidol on insect growth and development, as well as its underlying molecular mechanism, remains unclear. Here, the effects of nerolidol on Spodoptera exigua were investigated under treatment at various sub-lethal doses (4.0 mg/mL, 1.0 mg/mL, 0.25 mg/mL). We found that a higher dose (4.0 mg/mL) of nerolidol significantly impaired the normal growth, development, and population reproduction of S. exigua, although a relatively lower dose (0.25 mg/mL) of nerolidol had no significant effect on this growth and development. Combined transcriptome sequencing and gene family analysis further revealed that four juvenile hormone esterase (JHE)-family genes that are involved in juvenile hormone degradation were significantly altered in S. exigua larvae after nerolidol treatment (4.0 mg/mL). Interestingly, the juvenile hormone esterase-like (JHEL) gene Sexi006721, a critical element responsive to nerolidol stress, was closely linked with the significant augmentation of JHE activity and JH titer in S. exigua (R2 = 0.94, p < 0.01). Taken together, we speculate that nerolidol can function as an analog of JH by modulating the expression of the enzyme genes responsible for degrading JH, resulting in JH disorders and ultimately disrupting the development of insect larvae. This study ultimately provides a theoretical basis for the sustainable control of S. exigua in the field whilst proposing a new perspective for the development of novel biological pesticides.

3D Porous VOx/N-Doped Carbon Nanosheet Hybrids Derived from Cross-Linked Dicyandiamide-Chitosan Hydrogels for Superior Supercapacitor Electrode Materials.

Three-dimensional porous carbon materials with moderate heteroatom-doping have been extensively investigated as promising electrode materials for energy storage. In this study, we fabricated a 3D cross-linked chitosan-dicyandiamide-VOSO4 hydrogel using a polymerization process. After pyrolysis at high temperature, 3D porous VOx/N-doped carbon nanosheet hybrids (3D VNCN) were obtained. The unique 3D porous skeleton, abundant doping elements, and presence of VOx 3D VNCN pyrolyzed at 800 °C (3D VNCN-800) ensured excellent electrochemical performance. The 3D VNCN-800 electrode exhibits a maximum specific capacitance of 408.1 F·g-1 at 1 A·g-1 current density and an admirable cycling stability with 96.8% capacitance retention after 5000 cycles. Moreover, an assembled symmetrical supercapacitor based on the 3D VNCN-800 electrode delivers a maximum energy density of 15.6 Wh·Kg-1 at a power density of 600 W·Kg-1. Our study demonstrates a potential guideline for the fabrication of porous carbon materials with 3D structure and abundant heteroatom-doping.

Rational design of activated graphitic carbon spheres with optimized ion and electron transfer channels for zinc-ion hybrid capacitors.

Herein, three-dimensional activated graphitic carbon spheres (AGCS) were constructed by simultaneous activation-graphitization of Fe-tannic acid coordination spheres with the assistance of KOH. Nanosheets-assembled AGCS with complex intersecting channel system can expose more active sites for charge storage. Simultaneous activation-graphitization can relieve trade-off relationship between porosity and conductivity of carbon materials. Benefiting from multiple synergistic effects of large specific surface area (2069 m2 g-1), abundant ion-accessible micropores (>0.78 nm), good electronic conductivity (IG/ID = 1.11), and moderate amount of oxygen doping, the optimized AGCS-2 has favored ion and electron transfer channels. AGCS-2 based zinc-ion hybrid capacitor (ZIHC) displays a high specific capacity of 148.6 mA h g-1 (334 F g-1) at 0.5 A g-1, a remarkable energy density of 119.0 W h kg-1 at 1440 W kg-1, and superior cycling life with 96% capacity retention after 10,000 cycles. This simultaneous activation-graphitization strategy may open up a new avenue to design novel carbon spheres linking optimal pores and graphitic carbon structure for ZIHC application.

In Situ Low-Temperature Carbonization Capping of LiFePO4 with Coke for Enhanced Lithium Battery Performance.

Lithium batteries incorporating LiFePO4 (LFP) as the cathode material have gained significant attention in recent research. However, the limited electronic and ionic conductivity of LFP poses challenges to its cycling performance and overall efficiency. In this study, we address these issues by synthesizing a series of LiFePO4/carbon (LFP/C) composites through low-temperature carbonization coating of LFP in the presence of Coke as the carbon source. The resulting lithium batteries utilizing LFP/C as the cathode material exhibited impressive discharge specific capacities of 148.35 mA·h/g and 126.74 mA·h/g at 0.1 C and 1 C rates, respectively. Even after 200 cycles of charging and discharging, the capacities remained remarkably high, with values of 93.74% and 97.05% retention, showcasing excellent cycling stability. Notably, the LFP/C composite displayed exceptional rate capability, and capacity retention of 99.27% after cycling at different multiplication rates. These findings underscore the efficacy of in situ low-temperature carbonization capping of LFP with Coke in significantly improving both the cycling stability and rate capability of lithium batteries.

Tunable Resistive Switching Behaviors and Mechanism of the W/ZnO/ITO Memory Cell.

A facile sol-gel spin coating method has been proposed for the synthesis of spin-coated ZnO nanofilms on ITO substrates. The as-prepared ZnO-nanofilm-based W/ZnO/ITO memory cell showed forming-free and tunable nonvolatile multilevel resistive switching behaviors with a high resistance ratio of about two orders of magnitude, which can be maintained for over 103 s and without evident deterioration. The tunable nonvolatile multilevel resistive switching phenomena were achieved by modulating the different set voltages of the W/ZnO/ITO memory cell. In addition, the tunable nonvolatile resistive switching behaviors of the ZnO-nanofilm-based W/ZnO/ITO memory cell can be interpreted by the partial formation and rupture of conductive nanofilaments modified by the oxygen vacancies. This work demonstrates that the ZnO-nanofilm-based W/ZnO/ITO memory cell may be a potential candidate for future high-density, nonvolatile, memory applications.

A Facile Hydrothermal Synthesis and Resistive Switching Behavior of α-Fe2O3 Nanowire Arrays.

A facile hydrothermal process has been developed to synthesize the α-Fe2O3 nanowire arrays with a preferential growth orientation along the [110] direction. The W/α-Fe2O3/FTO memory device with the nonvolatile resistive switching behavior has been achieved. The resistance ratio (RHRS/RLRS) of the W/α-Fe2O3/FTO memory device exceeds two orders of magnitude, which can be preserved for more than 103s without obvious decline. Furthermore, the carrier transport properties of the W/α-Fe2O3/FTO memory device are dominated by the Ohmic conduction mechanism in the low resistance state and trap-controlled space-charge-limited current conduction mechanism in the high resistance state, respectively. The partial formation and rupture of conducting nanofilaments modified by the intrinsic oxygen vacancies have been suggested to be responsible for the nonvolatile resistive switching behavior of the W/α-Fe2O3/FTO memory device. This work suggests that the as-prepared α-Fe2O3 nanowire-based W/α-Fe2O3/FTO memory device may be a potential candidate for applications in the next-generation nonvolatile memory devices.

The Effect of Nitrogen Annealing on the Resistive Switching Characteristics of the W/TiO2/FTO Memory Device.

In this paper, the effect of nitrogen annealing on the resistive switching characteristics of the rutile TiO2 nanowire-based W/TiO2/FTO memory device is analyzed. The W/TiO2/FTO memory device exhibits a nonvolatile bipolar resistive switching behavior with a high resistance ratio (RHRS/RLRS) of about two orders of magnitude. The conduction behaviors of the W/TiO2/FTO memory device are attributed to the Ohmic conduction mechanism and the Schottky emission in the low resistance state and the high resistance state, respectively. Furthermore, the RHRS/RLRS of the W/TiO2/FTO memory device is obviously increased from about two orders of magnitude to three orders of magnitude after the rapid nitrogen annealing treatment. In addition, the change in the W/TiO2 Schottky barrier depletion layer thickness and barrier height modified by the oxygen vacancies at the W/TiO2 interface is suggested to be responsible for the resistive switching characteristics of the W/TiO2/FTO memory device. This work demonstrates the potential applications of the rutile TiO2 nanowire-based W/TiO2/FTO memory device for high-density data storage in nonvolatile memory devices.

Monodisperse MoS2/Graphite Composite Anode Materials for Advanced Lithium Ion Batteries.

Traditional graphite anode material typically shows a low theoretical capacity and easy lithium decomposition. Molybdenum disulfide is one of the promising anode materials for advanced lithium-ion batteries, which possess low cost, unique two-dimensional layered structure, and high theoretical capacity. However, the low reversible capacity and the cycling-capacity retention rate induced by its poor conductivity and volume expansion during cycling blocks further application. In this paper, a collaborative control strategy of monodisperse MoS2/graphite composites was utilized and studied in detail. MoS2/graphite nanocomposites with different ratios (MoS2:graphite = 20%:80%, 40%:60%, 60%:40%, and 80%:20%) were prepared by mechanical ball-milling and low-temperature annealing. The graphite sheets were uniformly dispersed between the MoS2 sheets by the ball-milling process, which effectively reduced the agglomeration of MoS2 and simultaneously improved the electrical conductivity of the composite. It was found that the capacity of MoS2/graphite composites kept increasing along with the increasing percentage of MoS2 and possessed the highest initial discharge capacity (832.70 mAh/g) when MoS2:graphite = 80%:20%. This facile strategy is easy to implement, is low-cost, and is cosmically produced, which is suitable for the development and manufacture of advance lithium-ion batteries.

Post-synthesis introduction of dual functional groups in metal-organic framework for enhanced adsorption of moxifloxacin antibiotic.

Highly effective removal of antibiotics from aqueous solution is of importance while still faces challenge. Herein, we report a novel metal-organic framework (MOF) adsorbent, MOF-808-SIPA (SIPA, 5-sulfoisophthalic acid), constructed via post-synthesis exchange strategy. On the basis, dual active groups including sulfonic acid and carboxyl groups are successfully introduced. The novel MOF-808-SIPA exhibits a high adsorption capacity of 287.1 mg g-1 for moxifloxacin hydrochloride (MOX·HCl), superior to that (174.6 mg g-1) of the pristine MOF-808-AA (AA, acetic acid). Besides, MOF-808-SIPA shows rapid adsorption equilibrium of âˆ¼ 30 min, strong anti-interference ability from pH and inorganic ions, and feasible regeneration. The superiority renders MOF-808-SIPA a potential adsorbent for MOX removal. Density function theory (DFT) calculation and experiment confirm that H-bond interaction contributes largely to the excellent adsorption in MOF-808-SIPA. Our work provides a guideline for designing high-efficiency MOF-based adsorbent.

Thiol-decorated defective metal-organic framework for effective removal of mercury(II) ion.

Removal of mercury (Hg) ion from water is important while still faces challenges in capacity and adsorption speed. Herein, using thiol-containing mercaptoacetic acid (MA) as the template, we constructed a novel metal-organic framework (MOF) adsorbent, Zr-MSA-MA (MSA, mercaptosuccinic acid). Unlike other monodentate acids such as acetic acid and formic acid, MA benefits to maintain high-content binding sites, in the meantime of defect formation. On the basis, Zr-MSA-MA exhibits a high adsorption capacity of 714.8 mg g-1 for Hg2+ and fast adsorption kinetics, superior to other MOF-based adsorbents. Co-existing metal ions and pH have only slight interference for the adsorption behavior. Besides, the adsorption is proved to an endothermic reaction and the adsorbent can be regenerated based on a simple elution. Further analysis indicates the strong chemical bonding of Hg2+ and -SH is the main adsorption mechanism. Thus, our work demonstrates the Zr-MSA-MA can serve as a potential adsorbent for Hg2+, and provides a novel strategy to construct defective adsorbent via using active group-containing template.

The Influence of Cryogenic Treatment on the Microstructure and Mechanical Characteristics of Aluminum Silicon Carbide Matrix Composites.

Aluminum matrix composites have been widely used in aerospace and automotive fields due to their excellent physical properties. Cryogenic treatment was successfully adopted to improve the performance of aluminum alloy components, while its effect and mechanism on the aluminum matrix composite remained unclear. In this work, the effects of cryogenic treatment on the microstructure evolution and mechanical properties of 15%SiCp/2009 aluminum matrix composites were systematically investigated by means of Thermoelectric Power (TEP), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The results showed that TEP measurement can be an effective method for evaluating the precipitation characteristics of 15%SiCp/2009 aluminum matrix composites during aging. The addition of cryogenic treatment after solution and before aging treatment promoted the precipitation from the beginning stage of aging. Furthermore, the aging time for the maximum precipitation of the θ″ phase was about 4 h advanced, as the conduction of cryogenic treatment accelerates the aging kinetics. This was attributed to the great difference in the linear expansion coefficient between the aluminum alloy matrix and SiC-reinforced particles, which could induce high internal stress in their boundaries for precipitation. Moreover, the lattice contraction of the aluminum alloy matrix during cryogenic treatment led to the increase in dislocation density and micro defects near the boundaries, thus providing more nucleation sites for precipitation during the aging treatment. After undergoing artificial aging treatment for 20 h, the increase in dispersive, distributed precipitates after cryogenic treatment improved the hardness and yield strength by 4% and 16 MPa, respectively.

Construction of dual sulfur sites in metal-organic framework for enhanced mercury(II) removal.

Highly efficient removal of mercury ion (Hg2+) from aqueous solution is a serious concern. Herein, a novel metal-organic framework (MOF) containing dual sulfur sites was successfully constructed via an in-situ method. Different with previous reports, thiophene and thiol sites were simultaneously introduced via organic linker and inorganic cluster, resulting in high-density sulfur sites. The composition and porosity of the newly synthesized DUT-67-SH (DUT, Dresden University of Technology) were systematically characterized. Based on abundant sulfur sites and strong host-guest interaction, DUT-67-SH exhibits a high adsorption capacity (370.2 mg g-1) and rapid adsorption kinetics (∼3 min for equilibrium). Excellent separation selectivity, regenerability, and applicability under wide acidic pH range were further confirmed. Mechanism analysis suggests that the chemical bonding between sulfurs and Hg2+ is the main driven force. Thus, our work demonstrates that DUT-67-SH is a potential adsorbent for Hg2+, and more importantly, provides a new insight for introducing high-density sulfur sites in MOFs.

Vanadium nitride nanoparticle decorated N-doped carbon nanotube/N-doped carbon nanosheet hybrids via a C3N4 self-sacrificing method for electrochemical capacitors.

Owing to the wide negative potential window (∼1.2 V) along with high specific capacitance (1340 F g-1) in alkaline electrolyte, vanadium nitride (VN) has been served as promising negative supercapacitor electrode material. However, VN is easy to dissolve during cycling process and shows low capacitance retainability. Herein, a hybrid electrode (marked as VN/NCNT/NCN), featuring VN nanoparticles and N-doped carbon nanotube inserted in N-doped carbon nanosheets, has been fabricated with a facile C3N4 self-sacrificing method. The porous structure and high conductive carbon skeleton, as well as the uniform distribution of VN nanoparticles give VN/NCNT/NCN a great amount of active site and fulfill excellent electrochemical performance for VN/NCNT/NCN-based electrode. The as-fabricated hybrid electrode exhibits a maximum specific capacitance of 232.9 F g-1 at 1 A g-1. Moreover, the cycling performance has been greatly improved and the specific capacitance remains 91% after 5000 cycles.

Caterpillar-Induced Rice Volatile (E)-ß-Farnesene Impairs the Development and Survival of Chilo suppressalis Larvae by Disrupting Insect Hormone Balance.

Significant research progress has recently been made on establishing the roles of tps46 in rice defense. (E)-ß-farnesene (Eßf) is a major product of tps46 activity but its physiological functions and potential mechanisms against Chilo suppressalis have not yet been clarified. In the present study, C. suppressalis larvae were artificially fed a diet containing 0.8 g/kg Eßf and the physiological performance of the larvae was evaluated. In response to Eßf treatment, the average 2nd instar duration significantly increased from 4.78 d to 6.31 d while that of the 3rd instar significantly increased from 5.70 d to 8.00 d compared with the control. There were no significant differences between the control and Eßf-fed 4th and 5th instars in terms of their durations. The mortalities of the 2nd and 3rd Eßf-fed instars were 21.00-fold and 6.39-fold higher, respectively, than that of the control. A comparative transcriptome analysis revealed that multiple differentially expressed genes are involved in insect hormone biosynthesis. An insect hormone assay on the 3rd instars disclosed that Eßf disrupted the balance between the juvenile hormone and ecdysteroid levels. Eßf treatment increased the juvenile hormones titers but not those of the ecdysteroids. The qPCR results were consistent with those of the RNA-Seq. The foregoing findings suggested that Eßf impairs development and survival in C. suppressalis larvae by disrupting their hormone balance. Moreover, Eßf altered the pathways associated with carbohydrate and xenobiotic metabolism as well as those related to cofactors and vitamins in C. suppressalis larvae. The discoveries of this study may contribute to the development and implementation of an integrated control system for C. suppressalis infestations in rice.

Rationally Tailoring Pore and Surface Properties of Metal-Organic Frameworks for Boosting Adsorption of Dy3.

The adsorption and recovery of dysprosium ions (Dy3+) from industrial wastewater are necessary but still challenging. Herein, we constructed a series of defect-containing metal-organic frameworks (MOFs) [UiO-66-(COOH)2] using sodium benzoate (BCNa) as a modulator. Upon the formation of defects, the porosity and surface charge properties of the MOFs were improved, leading to a higher utilization ratio of active groups and higher adsorption capacities for Dy3+. The synthesized UiO-66-(COOH)2-B10 with an optimal addition of BCNa exhibited a superior adsorption capacity of 150.6 mg g-1. Fast adsorption occurred at ∼5 min, and equilibrium was reached at ∼60 min. Higher pH and temperature were found to be beneficial for boosting Dy3+ adsorption, and selective adsorption over other metal ions was achieved in a multicomponent solution. Further, FTIR spectroscopy and XPS investigations indicate that free carboxyl contributes to the capture of Dy3+. Thus, this work provides a promising strategy to enhance the utilization ratio of active groups and further adsorption performance.

Synergistic effect of carboxyl and sulfate groups for effective removal of radioactive strontium ion in a Zr-metal-organic framework.

Rapid removal of radioactive strontium from nuclear wastewater is of great significance for environmental safety and human health. This work reports the effective adsorption of strontium ion in a stable dual-group metal-organic framework, Zr6(OH)14(BDC-(COOH)2)4(SO4)0.75 (Zr-BDC-COOH-SO4), which contains strontium-chelating groups (-COOH and SO4) and a strongly ionizable group (-COOH). Zr-BDC-COOH-SO4 exhibits very rapid adsorption kinetics (<5 min) and a maximum adsorption capacity of 67.5 mg g-1. The adsorption behaviors can be well fitted to the pseudo-second-order model and the Langmuir isotherm model. Further investigations indicate that the adsorption of Sr2+ onto Zr-BDC-COOH-SO4 would not be obviously affected by solution pH and adsorption temperature. The feasible regeneration of the adsorbent was also demonstrated using a simple elution method. Mechanism investigation suggests that free -COOH contributes to the rapid adsorption based on electrostatic interaction, while the introduction of -SO4 significantly enhanced the adsorption capacity. Thus, these results suggest that Zr-BDC-COOH-SO4 is a potential candidate for Sr2+ removal. They also introduce dual groups as an effective strategy for designing high-efficiency adsorbents.