Control of Streptomyces alfalfae XY25T Over Clubroot Disease and Its Effect on Rhizosphere Microbial Community in Chinese Cabbage Field Trials

Clubroot caused by Plasmodiophora brassicae is one of the most destructive diseases in cruciferous crops. Streptomyces alfalfae XY25T, a biological control agent, exhibited great ability to relieve clubroot disease, regulate rhizosphere bacterial and fungal communities in Chinese cabbage, and promote its growth in greenhouse. Therefore, field experiments were carried out to investigate the effects of S. alfalfae XY25T on clubroot and rhizosphere microbial community in Chinese cabbage. Results showed that the control efficiency of clubroot by S. alfalfae XY25T was 69.4%. Applying the agent can alleviate soil acidification; increase the contents of soil organic matter, available nitrogen, available phosphorus, and available potassium; and enhance activities of invertase, urease, catalase, and alkaline phosphatase. During Chinese cabbage growth, bacterial diversity decreased first and then increased, and fungal diversity decreased gradually after inoculation with S. alfalfae XY25T. High-throughput sequencing analysis showed that the main bacterial phyla were Proteobacteria, Bacteroidetes, Acidobacteria, and Planctomycetes, and the major fungal phyla were Ascomycota and Basidiomycota in rhizosphere soil. The dominant bacterial genera were Flavobacterium, Candidatus, Pseudomonas, Stenotrophomonas, Sphingomonas, Flavisolibacter, and Gemmatimonbacteria with no significant difference in abundance, and the major fungal genera were Monographella, Aspergillus, Hypocreales, Chytridiaceae, Fusarium, Pleosporales, Agaricales, Mortierella, and Pleosporales. The significant differences were observed among Pleosporales, Basidiomycota, Colletotrichum, two strains attributed to Agaricales, and another two unidentified fungi by using S. alfalfae XY25T. Moreover, quantitative real-time PCR results indicated that P. brassicae content was significantly decreased after the agent inoculation. In conclusion, S. alfalfae XY25T can affect rhizosphere microbial communities; therefore, applying the agent is an effective approach to reduce the damage caused by clubroot

Screening and Expression Analysis of Key Regulator Genes Associated with (Z)-3-Hexenal and (E)-2-Hexenal Transformation during Manufacturing Process of Oolong Tea

In this study, the contents of (Z)-3-hexenal and (E)-2-hexenal during oolong tea processing were measured and four (3Z):(2E)-hexenal isomerase (HI) genes were selected based on transcriptomic data. Meanwhile, the correlation between the changes of (Z)-3-hexenal and (E)-2-hexenal contents and related gene expression was analyzed. The results indicated that during oolong tea processing, one of the two compounds fell, while the other rose. Mechanical damage caused by tossing increased and reduced the contents of (Z)-3-hexenal and (E)-2-hexenal, respectively. Subsequent spreading contributed to the transformation of (Z)-3-hexenal into (E)-2-hexenal, resulting in an increase in the content of (E)-2-hexenal. The four selected genes all responded to mechanical stress and water deficit stress. The constructed phylogenetic tree indicated that CsHI was closely related to many germin-like proteins in plants such as tea (Camellia sinensis) and carrot (Daucus carota). This study provides a reference for clarifying the formation and transformation mechanism of volatile substances during oolong tea processing and improving the quality of oolong tea

High thermal conductivity of porous graphite/paraffin composite phase change material with 3D porous graphite foam

Phase change materials (PCMs) are widely used in the field of thermal management and energy storage, but both low thermal conductivity and leakage problem limit their broad applications. In this work, a 3D porous graphite (PG) foam was prepared by a pressing and drying method with solid mixture of graphite powder and ammonium bicarbonate (NH4HCO3), and it was used as the thermal conductive skeleton and shape stabilizer of PCMs. PG/paraffin composite PCMs (CPCMs) were then prepared by the vacuum impregnation of liquid paraffin into PG foam. It showed that the skeleton of 3D PG foam greatly improves the thermal conductivity of CPCMs. The prepared PG/paraffin CPCMs exhibited an ultra-high thermal conductivity of 19.27 Wm-1K−1 at a volume fraction 35.55% of graphite, which is about 76.08 times higher than that of paraffin. The heat conduction mechanism of the PG/paraffin CPCMs are analyzed, and it is found that Maxwell-Eucken model can be used to accurately predict its thermal conductivity. Moreover, the CPCMs show good performance of thermal shape stability and exhibit superior anti-leakage characteristic. The proposed method for the preparation of 3D PG foam is robust, and the excellent performance of their based CPCMs will be promising in the field of heat dissipation and thermal storage

A Glimepiride-Metformin Multidrug Crystal: Synthesis, Crystal Structure Analysis, and Physicochemical Properties

A multidrug crystal based on drug combinations was synthesized by the solvent evaporation method. This multicomponent crystal consisted of antidiabetic drugs Glimepiride (Gli) and Metformin (Met), which was performed by single crystal X-ray structure analysis. The results showed an enhancement of the pharmaceutical properties such as lower hygroscopicity and greater accelerated stability than the parent drug Met, and a higher solubility and dissolution rate than Gli

Experimental and numerical studies on spray characteristics of an internal oscillating nozzle

© 2019 by Begell House, Inc. An open atomization test bench based on high-speed Schlieren technology and a Malvern particle size analyzer was developed to investigate the effects of different injection pressures (0.12 MPa to 0.24 MPa) on spray characteristics of an internal oscillating nozzle, including the spatial distribution of flow rate, oscillation frequency, spray cone angle, spatial distribution of spray particle size, and velocity. A numerical investigation that simultaneously considered the internal flow field and the external spray within the same computational field was performed to reveal the oscillation mechanism. The experimental results indicated that the spray of the internal oscillating nozzle shows a fan shape distribution with small flow in the middle and large distribution on both sides. The flow rate gradually increases with the rising of injection pressure and reaches its maximum at 0.24 MPa when the distance from the nozzle is constant. The oscillating frequency keeps an upward tendency with a maximum growth rate when the injection pressure ascends from 0.15 MPa to 0.18 MPa. The spray cone angle does not change significantly with the increase of the injection pressure, fluctuating at approximately 41.8 degrees. Moreover, a critical injection pressure is obtained, below which the droplet size increases with the rise of the injection pressure and above which the droplet size declines moderately. The numerical investigation revealed that the oscillation phenomenon was generated due to the periodic establishing and vanishing of the pressure gradient within the feedback channels, and the Coanda effect occurred in the main flow passage

A Novel Polyvinylidene Fluoride Tree-Like Nanofiber Membrane for Microfiltration

A novel polyvinylidene fluoride (PVDF) tree-like nanofiber membrane (PVDF-TLNM) was fabricated by adding tetrabutylammonium chloride (TBAC) into a PVDF spinning solution via one-step electrospinning. The structure of the prepared membranes was characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and pore size analysis, and the hydrophilic property and microfiltration performance were also evaluated. The results showed that the tree-like nanofiber was composed of trunk fibers and branch fibers with diameters of 100–500 nm and 5–100 nm, respectively. The pore size of PVDF-TLNM (0.36 μm) was smaller than that of a common nanofiber membrane (3.52 μm), and the hydrophilic properties of the membranes were improved significantly. The PVDF-TLNM with a thickness of 30 ± 2 μm showed a satisfactory retention ratio of 99.9% against 0.3 μm polystyrene (PS) particles and a high pure water flux of 2.88 × 104 L·m−2·h−1 under the pressure of 25 psi. This study highlights the potential benefits of this novel PVDF tree-like nanofiber membrane in the membrane field, which can achieve high flux rates at low pressure