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Pestalotiopsis guepinii is a pathogenic fungus that causes grey blight on Camellia pitardii. In this study, we investigated the enzyme activity and kinetics of these cell‐wall‐degrading enzymes (CWDEs) produced by Pestalotiopsis guepinii in both C. pitardii leaves and culture medium. Our enzyme activity experiments revealed that the activities of xylanase, pectin methyl‐galacturonase (PMG), β‐1,4‐endoglucanase (Cx), and β‐glucosidase were high in both C. pitardii leaves and culture medium. These enzymes played a significant role in the pathogenic process. However, the activity of laccase was found to be very low and had a minor impact on the pathogenic process. Furthermore, our enzyme dynamics experiments demonstrated that the optimal reaction temperature for PMG and Cx was 50°C, while for β‐glucosidase and xylanase, it was 60°C. The optimal reaction pH for Cx, β‐glucosidase, and xylanase was 5.0, whereas for PMG, it ranged from 5.0 to 6.0. This indicates that these four enzymes prefer acidic conditions. Moreover, we observed that the activities of Cx, PMG, and xylanase decreased with increasing reaction time. On the other hand, the activity of β‐glucosidase initially increased sharply and then decreased slowly. The maximum reaction rates of the four cell‐wall‐degrading enzymes were ranked as follows: xylanase > PMG > β‐glucosidase > Cx. Additionally, the affinities of these enzymes with substrates were ranked as follows: PMG < Cx < xylanase < β‐glucosidase. [ABSTRACT FROM AUTHOR]

To better understand the mechanism of carbon deposition, the ex-situ catalytic pyrolysis of polyethylene (PE) was explored over a FeNi/Al 2 O 3 catalyst, and the evolution of volatiles as well as the yield and structure of carbon products at different temperatures were analyzed in depth by an in-situ atmospheric pressure photoionization high-resolution mass spectrometry (APPI HRMS) combined with a fixed-bed reactor. The results show that raising the pyrolysis temperature (from 500 to 800 °C) reduces carbon product yield and H 2 production, and the proportion of carbon nanotubes (CNTs) in the carbon products decreases. The source of carbon products gradually shifts from liquid-phase carbon sources to gaseous-phase carbon sources. Below 700 °C, both the outer diameter and carbon interlayer spacing of CNTs decrease, while above 700 °C, they both increase along with increased distortion of carbon layers. It is also observed that the carbon layers are connected to the catalyst lattice stripes, and the interlayer spacing of carbon layers is greater than the catalyst lattice spacing. In situ mass spectrometry reveals a significant increase in the carbon number and double bond equivalent (DBE) values of volatiles with increasing pyrolysis temperature, but the rate of increase slows down after 700 °C. Volatiles from lower pyrolysis temperatures undergo severe polymerization, upon entering the catalytic zone at higher temperatures, minimizing temperature-induced distinctions. Nevertheless, it remains evident that volatiles from lower pyrolysis temperatures exhibit less pronounced polymerization when exposed to higher catalytic temperatures. [ABSTRACT FROM AUTHOR]

An innovative and effective approach for screw design and optimization has been proposed, derived from multi-field synergy to address a growing challenge affected by the inadequate mixing and thermal management in plasticizing process of extrusion or injection. Dimensionless field synergy equations for incompressible non-Newtonian viscous polymers were established, and subsequently, two new types of screw structures—field synergy torsion element (FST) and field synergy elongation element (FSE)—were designed, fabricated, and validated through both simulation and experiment. Spiral and elongational flows were established in the newly designed screws owing to their unique structures of torsion channel and convergent channel, promoting the shear and stretch ductile deformations of polymer melt, documented to be a meaningful progress on flow patterns generated by conventional screw. A comparative investigation in this work of the newly designed screw with a conventional one showed that the newly proposed screws equipped with FSTs or FSEs performed better mixing and improved heat transfer and thermal uniformity. Multi-field synergy analysis revealed that the spiral and elongational flow enhanced the radial convection, improved the dependence of velocity and velocity gradient fields to facilitate melt stretching deformation as well as the dependence of velocity and temperature gradient fields to achieve heat transfer enhancement. [ABSTRACT FROM AUTHOR]

Arthrinium phaeospermum is the major pathogen responsible for the significant stem disease "blight" in B. pervariabilis × D. grandis. The interacting proteins of the key pathogenic factor ApCtf1β, BDUbc and BDSKL1, have previously been obtained by two-hybrid, BiFC, GST pull-down yeast assays. However, the functions of these interacting proteins remain unknown. This study successfully obtained transgenic plants overexpressing BDUbc, BDSKL1, and BDUbc + BDSKL1 via Agrobacterium-mediated gene overexpression. qRT-PCR analysis revealed significantly increased expression levels of BDUbc and BDSKL1 in the transgenic plants. After infection with the pathogenic spore suspension, the disease incidence and severity index significantly decreased across all three transgenic plants, accompanied by a marked increase in defense enzyme levels. Notably, the co-transformed plant, OE-BDUbc + BDSKL1, demonstrated the lowest disease incidence and severity index among the transgenic variants. These results not only indicate that BDUbc and BDSKL1 are disease-resistant genes, but also that these two genes may exhibit a synergistic enhancement effect, which further improves the resistance to blight in Bambusa pervariabilis × Dendrocalamopsis grandis. [ABSTRACT FROM AUTHOR]