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Microwave heating is considered an environmentally friendly and cost-effective method for sintering. Temperature field regulation and local hotspots are gaining widespread attention during microwave sintering. In this study, sol-gel method was employed to synthesize SiC fibers via microwave heating by uniformly combining the raw materials with Cu and Ni catalysts. The thermal effects and growth mechanisms of SiC were investigated using COMSOL Multiphysics software and DFT calculations for samples with Cu and Ni catalysts, respectively. The occurrence of magnetic losses played a significant role at low temperatures in the samples with Ni catalyst, resulting in the formation of local hotspots and the formation of molten Ni–Si alloys.Whereas, a reflection effect was observed in the samples with Cu catalyst, resulting in a more uniform temperature distribution. The V-L-S growth mechanism was identified in the SiC fibers synthesized with Ni catalyst during microwave heating, while the V–S growth mechanism was observed in the SiC particles synthesized with Cu catalyst. [ABSTRACT FROM AUTHOR]

Understanding the impacts of tillage on soil microflora, especially functional microbes related to nitrogen conversion, is essential for ensuring the sustainable production, biodiversity and function of agroecosystems in salinized soils. Based on a two-year field plot experiment in a salt-affected farmland, the effects of three tillage methods, namely, CT (conventional rotary tillage, depth 25 cm), VRT (vertical rotary tillage, depth 25 cm) and DVRT (deep vertical rotary tillage, depth 50 cm), on soil physicochemical properties and ammonia-oxidizing archaea (AOA), bacteria (AOB) and comammox bacteria (CAOB) communities were investigated. Soil samples over the sunflower (Helianthus annuus L.) growing season were collected on three dates, i.e., April 28, July 6, and September 6, 2020. The results indicated that CT, VRT and DVRT had the lowest EC 1:5 values (0.75–1.23 dS/m) and the highest OC (organic carbon, 14.50–19.32 g/kg), WSA1 (> 2 mm water-stable aggregates, 31.05–37.88 g/kg), and WSA2 (2–0.25 mm water-stable aggregates, 69.51–83.70 g/kg) values on the middle sampling date. The average number of OTUs was 51.2 ± 3.3, 43.2 ± 3.8 and 42.8 ± 6.2 (mean ± SD) per soil sample for AOA, AOB and CAOB, respectively. DVRT significantly affected the community richness indices (Sobs, ACE and Chao1) of AOA and AOB, whereas sampling dates shifted almost all the soil physicochemical properties and diversity indices (Shannon and Simpson) of AOA and AOB but not those of CAOB. Phyla Crenarchaeota , unclassified_d_Unclassified , Unclassified_k_norank_d_Archaea and Thaumarchaeota were the most common taxa (with relative abundances >5 %) of AOA under all the treatments. For AOB, >92 % of the taxa were categorized into the phylum Proteobacteria , and CT had a greater frequency of the phylum Proteobacteria than did VRT and DVRT on all sampling dates. For CAOB, approximately 90 % of the taxa were classified into the phylum Nitrospirae , and the relative abundance of Nitrospirae did not differ among the tillage practices, whereas VRT and DVRT had the highest relative abundance of Nitrospirae on the middle sampling date. A total of 88.69 % of the variation in the genus compositions of AOA, AOB and CAOB was explained by EC 1:5 , pH, OC, ρ b (bulk density), WSA1 and WSA2. In conclusion, tillage practices and sampling dates can diversely affect soil physicochemical properties, microbial richness and diversity indices of AOA, AOB and CAOB, and seasonal changes overwhelm tillage practices in shaping AOA, AOB and CAOB communities across the sunflower growing season in salinized irrigated farmland. • Tillage and sampling date dominated richness and diversity, respectively, for AOA and AOB. • Community richness and diversity of CAOB were only responsive to sampling date. • Tillage and seasons affected microbial communities by changing EC 1:5 , pH, OC, ρ b , WSA1 and WSA2. • Seasons overwhelmed tillage in shaping AOA, AOB and CAOB communities in sunflower growing season. [ABSTRACT FROM AUTHOR]

Pseudomonas plecoglossicida is a well-known pathogen of viscera granulomas disease in fish, which has led to severe economic losses. In our previous study, L321_RS13075 was predicted to be a key virulence gene of P. plecoglossicida during the host-pathogen interaction with Epinephelus coioides. To investigate the role of L321_RS13075 in the regulation of virulence in P. plecoglossicida , a L321_RS13075 knock-down strain was constructed. And a significant reduction in the ability of colonization, intracellular survival, motility, biofilm formation, and adhesion was detected in the L321_RS13075 knock-down strain. Compared with the wild-type strain, the silence of L321_RS13075 in P. plecoglossicida resulted in a significant change in the transcriptome of infected Epinephelus coioides (E. coioides). Results of COG and GO analysis on E. coioides showed that genes related to immune responses and inorganic ion transport were significantly affected by L321_RS13075 of P. plecoglossicida. Meanwhile, the interactions of the genes related to immune responses and inorganic ion transport were predicted, and the important hub genes were identified. Taken together, the results indicated that L321_RS13075 was a virulent gene of P. plecoglossicida , which significantly affected the immune responses and inorganic ion transport in E. coioides. ● Pseudomonas plecoglossicida is a temperature dependent bacterial pathogen in fish ● L321_RS13075 is critical for P. plecoglossicida virulence ● L321_RS13075 significantly affected the immune responses in E. coioides ● L321_RS13075 significantly affected the inorganic ion transport in E. coioides [ABSTRACT FROM AUTHOR]

SiC/Cu/Gr composites with a boundary of SiO 2 –Cu 2 O glass phase (GP) were manufactured through the hot pressing sintering process at a temperature of 950 °C. The influence of graphite (Gr) on the mechanical properties and tribological behavior under high-temperature were purposefully investigated. The microhardness of 1.37 ± 0.02 GPa is achieved by SiC/Cu/Gr composites with a graphite content of 1 vol%. The friction coefficient decreases significantly to 0.64 ± 0.02, while the average wear rate is as low as 2.2 × 10−3±0.02 mm3/(N·m) at a friction temperature of 500 °C. The results indicate that the excellent lubrication effect of graphite is utilized in the SiC/Cu/Gr composites, leading to a significant improvement in its high-temperature wear resistance performance. This behavior is attributed to the molten state of GP at high temperatures, which acts as a "binder" promoting high interface bonding strength between particles, coupled with the solid-phase lubrication provided by graphite. This research work provides a direction for developing and applying materials conducive to high-temperature contact conductivity. [ABSTRACT FROM AUTHOR]

High entropy oxide powders (ZrTiCoNiNb)O x were successfully synthesised using microwave heating with a TE666 resonant mode at temperatures ranging from 700 °C to 900 °C. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) techniques were carried out to characterize the samples, and the behavior of the samples when they undergo microwave heating was investigated. The mechanism of thermal field modulation (TFM) was explored to reduce the temperature gradients and improve heating efficiency. The temperature field distribution was simulated using COMSOL software. The process of synthesising (ZrTiCoNiNb)O x using microwave heating was found to comprise four stages: thermal accumulation, local solid-phase reaction, synchronous reaction and grain growth. A phase transition from multi-phase mixing to a fixed high entropy phase was observed. The effectiveness of the mechanism of thermal field modulation was confirmed via analogue computation and experimentation. [ABSTRACT FROM AUTHOR]

Al2O3‐mullite composites were prepared under the synergy effect of AlF3 and SiC aids by microwave heating. The phase composition, microstructure, porosity, flexural strength, thermal shock resistance, and thermal conductivity were investigated. The XRD results revealed that the content of mullite phase steadily increased with the increasing of AlF3 content. The microstructure showed that the lower content (≤1 wt%) of AlF3 led to the formation of granular mullite and the higher content (≥3 wt%) of AlF3 led to the formation of mullite whiskers, which could form an interlocking structure. In addition, the SiC hot spots can also promote the generation of mullite whiskers by microwave sintering. The thermal shock resistance was significantly improved by the interlocking structure of mullite whiskers. The residual rate of flexural strength of the composite with 3 wt% AlF3 was 86%. The composite with 3 wt% AlF3 additives got its optimized thermal conductivity from 30°C to 950°C, the value was between 0.819 and 1.021 W/(mK), which possess excellent thermal insulation performance. [ABSTRACT FROM AUTHOR]

Abstract Silicon carbide (SiC) crystals were synthesized by microwave sintering using coal and tetraethoxysilane (TEOS) as raw materials. A sol-gel method was carried out to coat coal mineral particles with silicon dioxide (SiO 2). The mixed raw powders were pre-formed by uniaxial pressing into cylindrical pellets in dimension of ~ 30 × 3 mm2. The pre-forming pressure was selected at 0 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa and 5 MPa respectively, which led to different apparent density of the green pellets. The influence of apparent density of green pellets on microwave heating behavior was investigated. Different microwave thermal effects were analyzed. Techniques of XRD、SEM were carried out to characterize samples. It was found that pre-forming pressure showed crucial influences on microwave thermal effects and electric field (E-field) intensification. No SiC crystal could be formed without pre-forming pressure. Pre-forming pressure might be the prerequisite for synthesis of SiC by microwave heating. Five consecutive and indispensable heating stages including accumulation of residual air, microwave plasma generation, complex chemical reactions, nucleation and grain growth of SiC crystallites could be distinguished for samples under pre-forming pressure. Different pre-forming pressure leads to changes in heating behavior as well as morphologies of SiC crystals. ~ 4 MPa might be the optimized pre-forming pressure for both microwave plasma effects and E-field intensification. [ABSTRACT FROM AUTHOR]

Nickel chloride was used as a catalyst to rapidly synthesize SiC fibers at lower temperatures via microwave heating. The effects of catalyst concentration and synthesis temperature on the morphology and composition of the product were studied. The synthesized SiC was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM)，X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The synthesis mechanism of SiC fibers under the action of the NiCl 2 catalyst was proposed. The results show that the stems of the bamboo-like nanowires are cubic β-SiC, and the nodes are composed of a large number of stacking faults, with diameters ranging from 20 to 100 nm. During the preparation process, the magnetic catalyst plays a crucial role in the rapid synthesis of SiC fibers. The gas-liquid growth mechanism of SiC fibers under the action of a magnetic-field-line-like Si-Ni compound is proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The strong hydrolysis of BSA by pepsin resulted in SQ fluorescence quenching. • This BSA-SQ assembly probe is simple in operation and fast in detection. • This fluorescence probe has a good selectivity and sensitivity. • This probe was successfully applied to the detection of salivary pepsin. Gastroesophageal reflux disease (GERD) is a highly prevalent condition. Screening for GERD remains a great challenge due to the non-specific nature of the symptoms. Now, salivary pepsin detection has become an effective tool for diagnosing GERD due to its non-invasive and highly specific advantages. However, the diagnosis of GERD by detecting pepsin in saliva still has factors such as long reaction time, poor selectivity, and low detection sensitivity, which need to be improved. In this work, bovine serum albumin (BSA) and a squaraine dye (SQ) were employed to build a BSA-SQ assembly with a fluorescent "on-off" change for rapid and sensitive detection of pepsin. In a Gly-HCl (pH = 2.6) buffer system, SQ had a significant aggregation caused-quenching (ACQ) effect. As SQ was embedded in the cavity of BSA, this improved its dispersion and inhibited the ACQ effect of SQ, resulting in enhanced fluorescence of the system. At this stage, pepsin catalyzed the hydrolysis of BSA, leading to the aggregation of SQ and the quenching of the fluorescence of BSA-SQ. The high catalytic activity of pepsin makes BSA-SQ suitable for the qualitative and quantitative detection of pepsin, showing a good linear relationship in the range of 0.5–40 μg/mL with a detection limit of 97 ng/mL. Finally, the use of this fluorescent probe method to detect pepsin in human saliva showed results consistent with conventional ELISA methods with relative errors between 0.4 and 5.5 %, confirming the great potential of BSA-SQ for the rapid diagnosis of GERD. [ABSTRACT FROM AUTHOR]

The dual defect mediated Z-scheme MoS 2 /g-C 3 N 4 photocatalyst was fabricated via a simple ultrasonic dispersion and annealing method. The structural, optical and electronic property was systematically characterized. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the MoS 2 was anchored on the g-C 3 N 4 through strong interface electrostatic interaction, which led to the formation of built-in electric field at the contact interface. The optimized MoS 2 /g-C 3 N 4 heterojunction achieved a superior photoefficiency towards bisphenol A (BPA) degradation and exhibited the reaction rate normalized to specific surface area of 3.22 × 10−4 g·min−1 m−2, approximately 10.0 and 6.7 times larger than these of g-C 3 N 4 and MoS 2 , respectively. The origin of the enhanced photocatalytic activity of MoS 2 /g-C 3 N 4 was attributed to the formation of intimate Z-scheme surface heterostructure between MoS 2 and g-C 3 N 4 , thus improved the light-harvesting ability, facilitated fast charge separation and created more active sites. The impact of anionic towards degradation efficiency was investigated. The degradation activity and degree of BPA were investigated by three-dimensional excitation-emission matrix (3D EEM) fluorescence technique. The Z-scheme charge transfer mechanism and the significant contribution of holes (h+) and superoxide radicals (O 2 −) were demonstrated by electron spinning resonance (EPR), radical scavenger experiment and spectral quantification technology. This work could offer a new protocol for the design of highly efficient heterostructure photocatalysts towards environmental remediation. [ABSTRACT FROM AUTHOR]

• The porous g-C 3 N 4 ultra-thin nanosheet with tunable nitrogen vacancy was obtained. • Nitrogen vacancy plays significant role in modulating photocatalytic properties. • The photocatalytic disinfection mechanism was deeply studied by multi technologies. In this work, porous defective g-C 3 N 4 ultrathin nanosheets were prepared through thermal condensation of freeze-dried precursor. First-principles density functional theory (DFT) calculations well predicted the role of V N in modulating energy levels and photocatalytic properties. The optimally defective g-C 3 N 4 manifested the better photocatalytic disinfection performance towards E. coli and S. aureus than pristine g-C 3 N 4 , respectively. The gradual damaged cell membrane for E. coli and the intimate mechanical constraint for S. aureus was imaged to further decipher the antibacterial behavior. The synergistic effect of enhanced visible light absorption ability, more exposed active sites and improved photogenerated charge separation was responsible for excellent photocatalytic disinfection activity. The photocatalytic disinfection mechanism towards E. coli was explored by electron spinning resonance (EPR), radical scavenger and spectral quantification technology, confirming the major role of h+ and O 2 −. This study provides alternative strategy for rational design of effective g-C 3 N 4 -based photocatalysts by defective engineering for environmental remediation. [ABSTRACT FROM AUTHOR]