Al matrix composites reinforced by in situ synthesized graphene–Cu hybrid layers: interface control by spark plasma sintering conditions

Tremendous impacts are usually made by the synthesis method and consolidation technique on microstructure and interface of graphene/Al composites. In the present work, an in situ gel-precursor decomposition route is proposed for the one-step synthesis of graphene nanosheet (GNS) decorated with Cu nanoparticles in the form of hybrid layers encapsulating Al grains (designated as GNS–Cu/Al). Consolidation is performed by spark plasma sintering (SPS) using markedly different sets of maximum temperature and maximum uniaxial pressure (400 °C/400 MPa or 500 °C/100 MPa). The powder and dense samples are investigated by several techniques including thermal analysis, X-ray diffraction and electron microscopy. The microhardness and elastic modulus of selected GNS–Cu/Al composites are investigated and related to the microstructure and preparation conditions. Results demonstrate that the interface structure is primarily determined by the roles of GNS–Cu hybrid layers and finely controlled by SPS conditions. This work paves a novel way to elucidate the evolutions of metal-decorated graphene hybrids in Al matrix composites

Phytolith Analysis for Differentiating between Foxtail Millet (Setaria italica) and Green Foxtail (Setaria viridis)

Foxtail millet (Setaria italica) is one of the oldest domesticated cereal crops in Eurasia, but identifying foxtail millets, especially in charred grains, and differentiating it from its wild ancestor, green foxtail (Setaria viridis), in the archaeobotanical remains, is still problematic. Phytolithic analysis provides a meaningful method for identifying this important crop. In this paper, the silicon structure patterns in the glumes, lemmas, and paleas from inflorescence bracts in 16 modern plants of foxtail millet and green foxtail from China and Europe are examined using light microscopy with phase-contrast and a microscopic interferometer. Our research shows that the silicon structure of ΩIII from upper lemmas and paleas in foxtail millet and green foxtail can be correspondingly divided into two groups. The size of ΩIII type phytolith of foxtail millet is bigger than that from green foxtail. Discriminant function analysis reveals that 78.4% of data on foxtail millet and 76.9% of data on green foxtail are correctly classified. This means certain morphotypes of phytoliths are relatively reliable tools for distinguishing foxtail millet from green foxtail. Our results also revealed that the husk phytolith morphologies of foxtail millets from China and Eastern Europe are markedly different from those from Western Europe. Our research gives a meaningful method of separating foxtail millet and green foxtail. The implications of these findings for understanding the history of foxtail millet domestication and cultivation in ancient civilizations are significant

A novel approach for efficient Ni nanoparticle doping of MgB2 by liquid-assisted sintering

Ni nanoparticles were successfully introduced for preparing polycrystalline MgB2 samples by a novel reduction method. According to transmission electron microscopy, the obtained Ni nanoparticles with average grain size of 5 nm are distributed in the B matrix without agglomeration. The missing shift in X-ray diffraction peaks indicates that Ni nanoparticles could not substitute Mg sites in the lattice, but rather form the ternary compound MgNi 2.5B2 above 600 C. The low-melting eutectic liquid formed by MgNi at 506 C is responsible for the formation of plate-like MgB2 grains and the fast fabrication of MgB2 at low temperature. The sample doped with nano-Ni has better grain connectivity and the critical current density (Jc) with respect to the commercial Ni-doped sample, but there is no improvement compare with the pure MgB2 sample. A sintering model was accounted for understanding the reaction between Mg and B with the assistance of Ni nanoparticles. 2006 IEEE

Transcriptome Analysis of Tryptophan-Induced Resistance against Potato Common Scab

Potato common scab (CS) is a worldwide soil-borne disease that severely reduces tuber quality and market value. We observed that foliar application of tryptophan (Trp) could induce resistance against CS. However, the mechanism of Trp as an inducer to trigger host immune responses is still unclear. To facilitate dissecting the molecular mechanisms, the transcriptome of foliar application of Trp and water (control, C) was compared under Streptomyces scabies (S) inoculation and uninoculation. Results showed that 4867 differentially expressed genes (DEGs) were identified under S. scabies uninoculation (C-vs-Trp) and 2069 DEGs were identified under S. scabies inoculation (S-vs-S+Trp). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that Trp induced resistance related to the metabolic process, response to stimulus, and biological regulation. As phytohormone metabolic pathways related to inducing resistance, the expression patterns of candidate genes involved in salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) pathways were analyzed using qRT-PCR. Their expression patterns showed that the systemic acquired resistance (SAR) and induced systemic resistance (ISR) pathways could be co-induced by Trp under S. scabies uninoculation. However, the SAR pathway was induced by Trp under S. scabies inoculation. This study will provide insights into Trp-induced resistance mechanisms of potato for controlling CS, and extend the application methods of Trp as a plant resistance inducer in a way that is cheap, safe, and environmentally friendly

iTRAQ-Based Proteomics Analysis of Response to Solanum tuberosum Leaves Treated with the Plant Phytotoxin Thaxtomin A

Thaxtomin A (TA) is a phytotoxin secreted by Streptomyces scabies that causes common scab in potatoes. However, the mechanism of potato proteomic changes in response to TA is barely known. In this study, the proteomic changes in potato leaves treated with TA were determined using the Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) technique. A total of 693 proteins were considered as differentially expressed proteins (DEPs) following a comparison of leaves treated with TA and sterile water (as a control). Among the identified DEPs, 460 and 233 were upregulated and downregulated, respectively. Based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, many DEPs were found to be involved in defense and stress responses. Most DEPs were grouped in carbohydrate metabolism, amino acid metabolism, energy metabolism, and secondary metabolism including oxidation–reduction process, response to stress, plant–pathogen interaction, and plant hormone signal transduction. In this study, we analyzed the changes in proteins to elucidate the mechanism of potato response to TA, and we provided a molecular basis to further study the interaction between plant and TA. These results also offer the option for potato breeding through analysis of the resistant common scab

Salt-template synthesis of mesoporous carbon monolith for ionogel-based supercapacitors

Mesoporous carbon monoliths (MCM) were prepared by using soluble salt as templates. During the synthesis, a freeze-drying process enables a surface coating of self-assembled Na2SiO3 salt particles with sucrose, which is further transformed into carbon by heat treatment. After removal of the salt templates by washing, MCM were obtained. MCM samples exhibit high specific surface area together with high mesoporous volume, whose pore sizes can be tuned from 10 to 30 nm by adjusting the ratio between salt and carbon sources. MCM materials were further used as electrodes in combination with ionogel electrolyte to assemble a solid-state supercapacitor. In this configuration, MCM electrodes show capacitance as high as 75 F g−1 and good rate performance thanks to the carbon monolith pore size selected. Keywords: Carbon monolith, Mesopores, Salt template, Ionogel, Solid-state supercapacitor

Enhancing Sugarcane Growth and Improving Soil Quality by Using a Network-Structured Fertilizer Synergist

High usage and low efficiency of fertilizers not only restrict sugarcane production but also destroy the soil environment in China. To solve this problem, a network-structured nanocomposite as a fertilizer synergist (FS) was prepared based on attapulgite (ATP) and polyglutamic acid (PGA). Field demonstrations were conducted from 2020 to 2021. Leaching tests and characterization were used to evaluate the ability of the network structure to control nutrient loss. The effects of FS on sugarcane growth and field soil quality were also investigated. The results showed FS could effectively reduce nitrogen loss by 20.30% and decrease fertilizer usage by at least 20%. Compared to fertilizer with the same nutrition, fertilizer with FS could enhance sugarcane yield and brix by 20.79% and 0.58 percentage points, respectively. Additionally, FS improved the soil physicochemical properties, including reducing the soil bulk density and increasing the contents of nitrogen, phosphorus, potassium, and organic matter. FS also altered the diversity of the bacteria and improved the bacterial richness. Our study shows this FS has a good ability to control nutrient loss, advance sugarcane agronomic traits, and improve soil quality. This work offers an option for the sustainable development of sugarcane through the novel FS