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关键词： root uptake   translocation   application timing   physicochemical parameters   site of action   weed spectrum  

摘要： Pre-emergence herbicides are taken up by seeds before germination and by roots, hypocotyls, cotyledons, coleoptiles or leaves before emergence, whereas post-emergence herbicides are taken up primarily by foliage and stems. Most modern pre-emergence herbicides are lipophilic, but post-emergence herbicides may be lipophilic or hydrophilic. The metabolic conversion of herbicides to inactive or active metabolites after plant uptake is of major importance for some compound classes. Several herbicides are proherbicides as for example some acetyl-coenzyme A carboxylase (ACCase)-inhibitors. The physicochemical characteristics of proherbicides and herbicides are usually unrelated. A major role can be attributed to the site of action at a cellular level. A great number of herbicides such as photosystem II (PS II)-inhibitors, protoporphyrinogen oxidase (PPO)-inhibitors or carotenoid biosynthesis inhibitors require light for activity. Others, such as cellulose-biosynthesis and mitotic inhibitors seem to be primarily active in belowground organs. Several lipophilic barriers against the uptake of xenobiotics exist in aboveground and belowground plant parts. The relevance of these barriers needs, however, further clarification. Uptake and translocation models are valuable tools for the explanation of the potential movement of compounds. Many factors other than uptake and translocation have, however, to be considered for the design of herbicides. For post-emergence herbicides, ultraviolet (UV) light stability, stability in formulations, and mixability with other agrochemicals have to be kept in mind while, in addition to the aforementioned factors soil interaction plays a major role for pre-emergence herbicides. In our opinion, general physicochemical characteristics of pre- or post-emergence herbicides do, unfortunately not exist yet. (c) 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

关键词： emissivity   glassy carbon   high temperature   mechanical properties   proton irradiation   VUV radiation  

摘要： In the frame of mission for the Sun approach, to understand the effects of the heating of the solar corona and the acceleration of the solar winds, research was carried out to study the behavior of glassy carbon that can be used for the heat shield. The physicochemical behavior of glassy carbon from 1600 up to 2100 K with or without proton bombardment and VUV irradiation was studied together with the measurement of the thermal optical properties, the ratio of the solar absorptivity to the total hemispherical emissivity conditioning the thermal equilibrium of the heat shield. Experimental results obtained on massive glassy carbon samples are presented through mass spectrometry, mass loss rate and microstructural characterization (XRD, SEM horizontal ellipsis ), mechanical and thermo-optical properties. Finally, the synergistic effect of high temperature, protons and VUV radiation has a low impact on this material.

关键词： Edible packaging film   Flaxseed protein   Alginate   Silver nanoparticles   Thermal properties  

摘要： In the present study, flaxseed protein-alginate films were prepared with different concentrations of silver nanoparticles (AgNPs) and were evaluated for the physicochemical, mechanical, barrier, and thermal properties. The presence of AgNPs in the protein-alginate films significantly affected the properties of films. Film thickness and moisture content increased proportionally with an increase in the concentration of AgNPs;however, the solubility was decreased. A decrease in L* value and an increase in a* and b* values, along with an increase in total color change was observed with the addition of AgNPs. The mechanical properties of films were improved with the addition of AgNPs, as indicated by the results of tensile strength and percentage elongation. Water vapor permeability was reduced, which showed the improvement in barrier properties of films. Differential scanning calorimetry and thermal gravimetric analysis results indicated improvement in the thermal stability of AgNPs incorporated flaxseed-alginate films. The study on the influence of AgNPs on bacterial inactivation showed that, compared to the control film, all films integrated with silver nanoparticles had strong antibacterial action. The inhibition zones obtained at various AgNP concentrations revealed that the antibacterial activity of AgNPs against Gram-negative (E. coli) bacteria was greater than that of Gram-positive (S. aureus) bacteria. Therefore, silver nanoparticles incorporated flaxseed protein-alginate films have the potential to be used as an antimicrobial food packaging film.

关键词： azoxystrobin   eutectics   interaction energy   molecular dynamics simulation   solubility  

摘要： Eutectics have invoked enormous interests as an inexpensive and greener excipient with promising applications. In this study, eutectics of azoxystrobin (AZO) with fludioxonil (FDO), adipic acid (AA), succinimide (SIM), and 2-imidazolidinone (IMD) are prepared by rotary evaporation in order to improve the solubility and dissolution rate of AZO. Differential scanning calorimetry and powder X-ray diffraction are used to distinguish eutectics. Interestingly, AZO forms form 2 at first and then forms eutectic at stoichiometric ratios of 7:3, 7:3/8:2, 7:3, and 6:4 with FDO, AA, IMD, and SIM, respectively. Compared with AZO, the solubility and dissolution rate of these four eutectics in water are improved. The molecular dynamics simulations between AZO and coformer molecules indicate that homologous hydrogen bonds are formed of conformer-coformer, which may lead to the formation of eutectic regions. Meanwhile, the interaction energies between AZO and coformers in these possible system boxes of the four eutectics are calculated. The results indicate that the interaction energy in AZO-FDO is greater than that in AZO-AA, AZO-SIM, and AZO-IMD.

关键词： Chitin-glucan complex   Isolation   Characterization   Pleurotus ostreatus   Mushroom  

摘要： Chitin-glucan complex, an essential organic ingredient in the inner layer of the fungal cell wall, was isolated from the stalk and cap of Pleurotus ostreatus mushroom using two methods. In the first, powder of water-insoluble part was treated with NaOH in 3 successive baths, whereas in the second method an additional step was performed using acetic acid for the effective removal of soluble proteins, free chitosan and minerals. The influence of the deproteinization process on the yield and purity of the chitin-glucan complex was assessed by variation of NaOH concentration, reaction time and number of *** biopolymer recovered by the first method (yield from stalk 49% of dry weight, Cri 63.19%) presented residual proteins, lipids and minerals (5.52%) whereas the purest copolymer (yield 41.1% and minerals 3.22% of dry weight, Cri 58.43%) was produced using the second method from the stalk;the latter was mostly considered as a valuable waste from an available bio-resource that can easily be cultivated. X-ray diffraction (XRD), thermal analyses, scanning electron microscope, energy-dispersive X-ray spectroscopy, infrared spectroscopy, Kjeldahl method and Biuret test were employed to prove purity and study the physicochemical properties. Furthermore, the isolated chitin-glucan complex was compared with the chitin extracted from Agaricus bisporus mushroom. Fungal chitin could constitute a viable alternative to commercial chitin with better performance in adsorption applications, and in this respect, the results revealed that the isolation of chitinous polysaccharide from P. ostreatus (41.1%) was higher than from most cultivated mushrooms (7-36.72%). [GRAPHICS] .

关键词： Silage   Coffee pulp   Large scale   Lactic acid bacteria   Yeast  

摘要： Purpose Coffee-pulp (CP) is an agricultural by-product produced in tropical regions. The high moisture and high carbohydrates content promote rapid spoilage by microorganisms together with detrimental consequences for the environment. Proper conservation of this biomass could be useful as a substrate for other processes. The feasibility of CP silage without any additive was studied at a large scale. Four silages were carried out each one containing 4.5 t of CP. Methods Coffee-pulp silage was monitored during three months and samples were collected at regular intervals of time. Samples were used to determine microbiological parameters (lactic acid bacteria and yeasts population) and physicochemical variables like dry matter, pH, water-soluble carbohydrates, organic acids and ethanol. Results In all the 4 silages carried out, a high level of lactic acid was rapidly reached, decreasing the pH. Additionally, acetic and propionic acids were produced inducing an antifungal effect. Limited ethanol production was observed in the first days of silage due to the yeast ' s activity. The internal temperature of silos rose indicating residual aerobic activity. Stable silage conditions in terms of high lactic acid concentration (> 8% DM), low pH (3.9) and no butyric acid production, were established during the first 72 h. These CP silage variables were kept constant after 30 days and until 90 days. Conclusion Coffee-pulp is a suitable agricultural by-product for in situ conservation at large-scale silage process without addition of inoculum.

关键词： pressure leaching   lignosulfonate   kinetics   sphalerite   apparent activation energy   reaction order  

摘要： The physicochemical regularities of the pressure oxidation leaching of a zinc sulfide concentrate in sulfuric acid are studied. The effect of the concentration of lignosulfonate (C-LSN = 0.2-0.8 g/dm(3)), duration of leaching (tau = 20-120 min), temperature (T = 393-423 K), and partial pressure of oxygen (PO2 = 0.3-0.7 MPa) on the extraction rate of zinc and iron into the solution, as well as the grain size distribution of the cakes, is found. It is shown that introducing LSN makes it possible to intensify the processes of extraction of zinc and iron. The maximum extraction of zinc and iron over 120 min of leaching at C-LSN = 0.6-0.8 g/dm(3) are 89 and 37%, respectively. The partial reaction order with respect to lignosulfonate is 0.3 for sphalerite and 0.9 for iron sulfides. The ambiguous effect of increasing temperature on the process under study is established. Increasing the temperature from 413 to 423 K leads to a decrease in the extraction of zinc by 3-4% due to the formation of sulfur-sulfide aggregates with a fineness of more than 150 mu m. The values of the apparent activation energy E-a of leaching of sphalerite and iron sulfides in the presence of lignosulfonate are calculated to be 30 and 45 kJ/mol, respectively. It is found that increasing the partial pressure of oxygen from 0.3 to 0.5 MPa has a positive effect on leaching and makes it possible to enhance the extraction of zinc (by 22%) and iron (by 27%) into the solution. However, upon increasing the partial pressure of oxygen up to 0.7 MPa in the presence of LSN, a decrease in the rate of leaching of zinc sulfide is noted after 40 min of the process, which may be associated with the degradation of lignosulfonate. It is found that the values of the partial orders of leaching reactions with respect to oxygen are 1.2 for sphalerite and 2.5 for iron sulfides.

关键词： Fertile islands   Bacteria   Heterogeneous distribution   Desert  

摘要： The "fertile islands" resulting from discrete plants are important for the structure and function of dryland ecosystems. To understand the spatial heterogeneity of soil biotic and abiotic resources as a result of fertile islands in deserts, soil bacterial and physicochemical profiles were measured at four soil depths (0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm) in three soil patches (under mid-canopies, at the edge of canopy cover, and in bare soil) around legumes (Hedysarum scoparium shrubs) and non-legumes (Artemisia ordosica shrubs). Unexpectedly, the patches of the two plants showed similar soil abiotic and biotic patterns. Copiotrophs and potential decomposers were enriched under mid-canopies, with more phylogenetically clustered bacterial communities, and co-occurrence networks with lower connectivity and higher modularity than in bare soil. In bare soil, oligotrophs and potential nitrate reducers were enriched. Soil properties showed less conspicuous spatial heterogeneity than bacterial communities. The only soil physicochemical properties enriched under mid-canopies were soil organic matter, dissolved organic carbon, and nitrate;their enrichment was significantly related to bacterial communities. This study elucidates the spatial patterns of soil properties and their relationships, which are observed in fertile islands of desert ecosystems, and provides further insights into the mechanisms of soil nutrient redistribution.

关键词： duck egg white   salting time   heat treatment   structure   in vitro digestion  

摘要： BACKGROUND The texture and structure of the duck egg white (DEW) gel under salt and heat treatment are crucial to its digestibility. Specifically, the structural changes of food protein gels have been recognized for their potential to regulate in vitro digestion. In this study, the effects of gel characteristics and simulated in vitro gastrointestinal digestion of DEW under combined salt and heat treatment were investigated. RESULTS With the increase in salting time and temperature, a porous opaque gel with large particles was formed, the moisture content of DEW showed a downward trend, and the same was true for hardness changes. The microstructure suggested that, with the penetration of NaCl, DEW proteins were denatured, and the protein molecules gradually unfolded and then aggregated after 7 days. The secondary structure revealed that, as the salting time and temperature increased, the proportion of intermolecular beta-sheets and alpha-helices decreased. In terms of in vitro digestion, the highest digestibility was obtained at 14 days of salting combined with 100 degrees C heat treatment, and the digestibility was the lowest when marinated for 7 days at 121 degrees C. Liquid chromatography and tandem mass spectrometry (LC-MS/MS) indicated that the number of different types of peptides and specific peptides was positively correlated with the salting time and temperature of the DEW at the end of gastric digestion. CONCLUSIONS Heat treatment at 100 degrees C has a higher in vitro digestibility than at 121 degrees C. Gels with low hardness, large pores, and rough textures are easier to digest by pepsin and release more peptides. (c) 2021 Society of Chemical Industry.

关键词： Mine road   Road dust   Compound dust suppressant   Dust suppressant performance  

摘要： Copper mine road dust is the major source of dust in mine operations. The dust produced on the road surface is a great hazard to the workers. Aiming at the road dust of an open-pit mine, this paper conducts a physical and chemical analysis of a new type of chemical dust suppressant. It is prepared by using sodium polyacrylate as a binder, sodium carbonate as a moisture absorbent, polyethylene glycol as a water-retaining agent, and alkyl glycoside as a surfactant. Physical and chemical characteristics and dust suppression performance of dust suppressant were tested. The results show that the dust suppressant has a pH of 11.03, a viscosity of 18.5 mPa center dot s, and a surface tension of 28.1 mN/m. The content of heavy metal ions contained is less than the maximum concentration defined by "The norms for the integrated treatment of copper mine acidic waste water." Under the same temperature condition, the greater the humidity, the stronger the hygroscopicity. Especially when the humidity is 30%, the hygroscopic effect is contrary to water. The dust suppressant also has good anti-evaporation properties, and it could maintain a moisture content of 4% to 5% after being placed at room temperature for 10 days. Compared with water, the dust suppressant has better performance of wind erosion, water erosion, and compression resistance. Under the same conditions, the loss rate of water is 2 times that of the dust suppressant, and the pressure of the dust suppressant sample is about 3 times that of water. The dust suppressant has a much higher dust removal efficiency for all dust and respirable dust than water under the same conditions. Finally, the test results and mechanism of the dust suppression mechanism of the dust suppressant are described and analyzed, which shows that the dust suppressant studied in this paper has good performance and is suitable for road dust prevention.