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关键词： Liquid   liquid electrochemistry   Microinterfaces   Berberine   Palmatine   Electroanalysis   Diffusioncoefficient   Ion transfer potential  

摘要： The electrochemical behaviour of the alkaloids berberine and palmatine at the polarized water/1,2-dichloroethane interface is studied by first time. The interface is supported on the micropores of a PET (polyethylene terephthalate) membrane by using an electrochemical cell employed in previous works. Chronoamperometry and square wave voltammetry are applied in order to determine the concentrations of the ions berberine and palmatine in water. Thus, calibration curves are built with both techniques and the resulting detection limits are discussed and compared. In addition, the chronoamperograms and square wave voltammograms recorded are used to estimate the standard transfer potentials and the aqueous diffusion coefficients for the two cations. The diffusion coefficient values are further compared with results of molecular dynamic simulations, finding a good correlation between experimental and simulated data.

关键词： Three different cow manures   Biochar   Pyrolysis conditions   Feedstock composition   Physicochemical characterization  

摘要： Pyrolysis, as a thermal decomposition process and environment-friendly technology, can be used for the safe treatment of cow manure. In this paper, the effects of pyrolysis conditions on the properties of biochar derived from different types of cow manure (i.e., fresh cow manure, flushing cow manure, and anaerobic fermentation residues) were studied using slow pyrolysis methods. The properties of feedstocks, thermal decomposition, and biochar were analyzed using elemental analysis, coarse fiber determination, TG-FTIR, ICP-MS, FTIR, XRD, and SEM-EDS. Results showed that the cow manure-derived feedstocks were rich in total organic C (>37%) and had no heavy metal risk. According to the results of TG-FTIR, pyrolysis produced more residual solids, CO, CH4, and NH3 and less CO2 than combustion. The factors affecting alkalinity, calorific value, adsorption capacity, and surface functional group properties of cow manure-derived biochar in order of effectiveness were as follows: pyrolysis temperature > manure characteristics > heating rate > residence time. In general, increasing the temperature from 300 degrees C to 700 degrees C increased the pH (8.05-11.74) and C content (45.75%-49.64%) of fresh cow manure biochar and decreased the yield (62.17%-39.82%), nutrient content (N + P + K = 6.90%-5.64%), iodine adsorption capacity (269-96 mg g(-1)), aromaticity, and polarity. The biochar derived from flushing cow manure and anaerobic fermentation residues had similar C content (>48%), alkalinity (pH > 10), calorific value (>20000 J g(-1)), stability, and polarity. Fresh cow manure biochar had higher nutrient recovery (6.6%) and iodine adsorption capacity (215 mg g(-1)) than others. Compared with flushing cow manure and anaerobic fermentation residues, the pyrolysis of fresh cow manure reduced nutrient loss and treatment energy consumption. This study provides a good basis for the optimization of the pyrolysis process of three typical kinds of cow manures in dairy farms.

关键词： Hybrid rice   Eating quality   Apparent amylose content   Physicochemical properties   Starch structure  

摘要： In this study, we compared the physicochemical properties and starch structures of hybrid rice varieties with similar apparent amylose content but different taste values. In addition to the apparent amylose content, gel permeation chromatography analysis showed that the higher proportions of amylopectin short chains and relatively lower proportions of amylopectin long chains, which could lead to higher peak viscosity and breakdown value, as well as a softer and stickier texture of cooked rice, were the key factors in determining the eating quality of hybrid rice. High-performance anion-exchange chromatography analyses showed that the proportion of amylopectin short chains (degree of polymerization 6-10) and intermediate chains (degree of polymerization 13-24), which might affect the gelatinisation enthalpy and crystallinity, also contributed greatly to the eating quality of hybrid rice. Moreover, this study indicated that a greater diversity of forms and sizes of starch granules might influence the eating quality of hybrid rice.

关键词： Anaerobic membrane bioreactors   Gel layer   Cake layer   Layer structure   Biological behavior  

摘要： As the main cause of membrane fouling, layer fouling necessitates further study to better understand its formation process and facilitate fouling control in anaerobic membrane bioreactors (AnMBRs). This study investigated the physicochemical and biological differences between the cake and gel layers in an AnMBR. The results indicated that total solids in the cake layer is forty times that in the gel layer. Nonetheless, the gel layer has a higher specific foulant resistance than that of the cake layer (6.3 x 1014/m/kg vs. 0.18 x 1014/m/kg), which results in comparable contributions of the two layers to membrane fouling. Sludge flocs with abundant extracellular proteins are the main foulants in the cake layer. Conversely, the gel layer has a homogeneous network structure formed by proteins and beta-D-glucopyranose polysaccharides with pore channels rich in cells. The genera Azovibrio (28.93%), Desulfovibrio (6.54%), and Syntrophobacter (2.84%) were predominant microbes in gel foulants, suggesting that biofouling triggered by quorum sensing played a more significant role in the formation of the gel layer when compared with the cake layer. The results of this study bring out the distinction between the cake and gel layers and highlight the role of the gel layer in the layer fouling of AnMBRs. Consequently, it provides fundamental knowledge for the control of membrane fouling.

关键词： Nonlinear optical   FT-NMR   Hirshfeld surfaces   HRXRD   First-order hyperpolarizability  

摘要： The '2-ethylimidazolium d-tartrate (2EIMDT)' C9H14N2O6 is synthesized and confirmed by experimental NMR, FTIR methods and powder XRD analysis. The HRXRD study reveals that the grown 2EIMDT is an ideally perfect single crystal without having any internal structural grain boundaries. It has good optical transmittance in the wavelength region of 250-1100 nm. The thermal stability of the crystal is ascertained up to 150 degrees C and the second harmonic generation activity of the crystal was studied by Kurtz-Perry powder technique. Etching analysis reveals the growth pattern and dislocation density of the crystal. A detailed analysis of the intermolecular interactions via Hirshfeld surface analysis and fingerprint plots revealed that the 2EIMDT structure is stabilized mainly by formation of O center dot center dot center dot H/H center dot center dot center dot O and H center dot center dot center dot H hydrogen bonds. The quantum-chemical computations were made to find the molecular properties. The HOMO-LUMO, molecular electrostatic potential, natural bond orbital, nonlinear optical behaviour of the 2EIMDT were studied with the same basis set in the gas phase, theoretically. (C) 2021 Elsevier B.V. All rights reserved.

关键词： chitin   film   green processing   hydrocolloid   media milling   solvent‐   free  

摘要： Chitin is a valuable natural material, but its applications are limited because of its insolubility in water. Size reduction of natural materials has been found to offer certain benefits, including enhancing dispersibility. We employed media milling to produce a chitin micro-suspension with water as the sole solvent, and to fabricate the chitin film. The particle size and molecular weight were decreased from 96.86 to 21.95 mu m and 173 to 75 kDa (M-n), respectively, post milling;however, the degree of deacetylation slightly increased (from 21.26 to 24.31) with milling time. Moreover, limited water-soluble fractions were generated, the quantity (1.5-2.0% d.b.) and molecular weight (M-n 15-34 kDa) of which were characterized. These fractions enabled the formation of a chitin film through the induction of hydrogen bonds. The particle size affected the morphology and mechanical properties of the film. The fabricated chitin film had tunable thickness (61.3-80.7 mu m), tensile strength (38.95-64.61 MPa), elongation (0.93%-2.16%), Young's modulus (2994-4246 MPa), WVP (12.04-17.79 g mm/m(2) day kPa), swelling ratio and surface smoothness. This novel method for fabricating chitin films through aqueous suspension can improve applications of chitin in packaging and particularly fulfill environmentally friendly requirements.

关键词： Lactobacillus brevis JLD715   sodium selenite   membrane damage   transcriptomic sequencing   metabolism mechanism  

摘要： BACKGROUND Elemental selenium, as a new type of selenium supplement, can be prepared by microorganisms reducing inorganic selenium. In this study, Lactobacillus brevis JLD715 was incubated in broth containing different concentrations of sodium selenite (Na2SeO3). RESULTS The results showed that the bacterial biomass of L. brevis JLD715 decreased due to the inhibition of Na2SeO3. The cell membrane of L. brevis JLD715 treated with Na2SeO3 was damaged, as evidenced by the reduction of intracellular ATP concentration, depolarization of cell membrane, reduction of intracellular pH and impairment of membrane integrity. In addition, we investigated the metabolism mechanism of Na2SeO3 by L. brevis JLD715 based on transcriptome sequencing. A total of 461 genes were significantly differentially expressed under Na2SeO3 treatment, of which 231 genes were up-regulated and 230 genes were down-regulated. These genes were involved in pathways such as pyruvate metabolism, fatty acid biosynthesis, selenocompound metabolism and nucleotide-binding oligomerization domain-like (NOD-like) receptor signaling. Meanwhile, the genes related to sulfhydryl oxidoreductase, electron carrier proteins and transmembrane transport proteins synthesis were significantly up-regulated. CONCLUSION To sum up, the findings of this research will contribute to providing support for the application of L. brevis JLD715 in selenium-enriched functional foods. (c) 2021 Society of Chemical Industry

关键词： Amaranth protein isolate   Functional characteristics   Extraction pH   Gelation dynamics   Thermal characteristics  

摘要： Results for the effect of extraction pH and pH treatment on the functional, physicochemical, rheological and thermal characteristics of amaranth protein isolates (APIs) are reported in this study. Four amaranth protein isolates (P1, P2, P3 and P4) were prepared by varying the extraction pH (9-11). These four protein isolate samples were further treated at pH values from 3 to 9. The total protein content and purity of protein isolates were found to be higher for P1 than P2, P3 and P4 samples. The particle size of P1 was significantly (p <= 0.05) higher (299.68 mu m) than other samples. Solubility, emulsifying capacity and stability, foaming properties, water and oil binding capacities were higher for the P1 sample treated at pH 9. Gelation characteristics like storage modulus (G') and loss modulus (G '') were higher for P1 samples. APIs obtained at extraction pH 9 (P1) also exhibited better thermal properties in comparison with other three samples.

关键词： apple cubes   high-pressure processing (HPP)   active coatings   foodborne pathogens   gastrointestinal digestion (GID)  

摘要： BACKGROUND: In recent years the use of high-pressure processing (HPP) of fruit products has steadily increased due to its antimicrobial effectiveness and the retention of nutritional and quality attributes compared to conventional thermal technologies. Edible coatings are already being used to enhance the quality of minimally processed fruits. Thus, apple cubes (AC) and alginate-vanillin-coated apple cubes (AVAC) were subjected to HPP (400 MPa/5 min/35 degrees C). The microbiological and physicochemical parameters were evaluated and the bioactive compounds were monitored before and after HPP of apple cubes. Also, an in vitro gastrointestinal digestion (GID) was conducted. RESULTS: HPP left L. monocytogenes counts below the detection limit (2 log UFC g(-1)), regardless of the presence of coating. For E. coli, HPP + active coating showed a synergism affording the greatest reduction (>5 log) for AVAC-HPP. Firmness was maintained in AVAC-HPP samples, while AC-HPP samples suffered reductions of 35%. Colour attributes were also better retained in AVAC-HPP samples. In general, HPP led to a decrease in phenolic compounds. Regarding the effects of GID, vanillin-based active coating exerted a protective effect on some phenolics. Thus, p-coumaroylquinic acid concentration was maintained for AVAC and AVAC-HPP during GID. Epigallocatechin, the compound with the highest concentration in apple cubes, increased for AVAC (106%) and AVAC-HPP (57%). Also, phloridzin concentration increased for AVAC-HPP (17%). At the end of GID, procyanidin B1 and epigallocatechin were the main phenolic compounds for all samples, AVAC showing the highest concentration. CONCLUSIONS: This work demonstrates that the combined application of HPP and active coatings on apple cubes could be used to obtain a safe and good-quality product. (c) 2021 Society of Chemical Industry

关键词： ZSM-5   FDU-12 composite   Different bath temperatures   Diesel   Hydrodesulfurization   Hydronitrogen  

摘要： A series of ZSM-5/FDU-12 (ZF-x) composite material with MFI microporous structure and face-centered cubic structure were successfully synthesized using the nano-assembly method under different water bath temperatures. The bath temperature had an apparent influence on the material's physical texture property. The catalytic hydrotreating performance were evaluated inside fix-bed unit, under the reaction conditions of 5 MPa and 350 degrees C. The sulfur and nitrogen contents of the products obtained from NiMo/ZFA-30 catalyst were reached 11.5 ppm and 4.8 ppm, respectively. The moderate acidity and the highest sulfidation ratio of active phases were responsible for the highest hydrodesulfurization (98.9 %) and hydrodenitrogenation (99.3 %) efficiency over the NiMo/ZFA-30 catalyst.