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关键词： Convolvulus arvensis   Microemulsion-based nanocarriers   Pluronics copolymer   Tribenuron-methyl  

摘要： Microemulsions have received particular interest as novel vehicles for drug delivery. Herein, a new tribenuronmethyl (TM) loaded oil-in-water Pluronic F127-stabilized microemulsion is developed as a promising delivery nanocarrier for herbicides to control the growth of wheat weed (Convolvulus arvensis). The diameter for the TM-loading microemulsions was determined to be 7.5 nm. Experimental results revealed a high entrapment (83% +/- 6%) and loading efficiency (0.44% +/- 0.07%) of TMin F127-stabilized microemulsions. The in-vitro release profile from the microemulsions ensured a controlled and sustained release of the loaded TM, with ca. 50% release of TM was achieved from the microemulsions within the first 35 h, in comparison to a complete release of free TM within the first 5 h. After 5 weeks, TM-microemulsions were able to reduce the fresh weight (76%), dry weight (55%), acetolactate synthase activity (83%), and plant height (79%) of C. arvensis in comparison with controls. Using a herbicide concentration as low as ca. 50% [15 g of active ingredient per hectare,g a.i. ha(-1))], of the recommended dose of commercial herbicides (Granstar) great inhibitions of weed growth were obtained. Therefore, the present microemulsion system opens the door to new nanocarriers for effective weed control to reduce economic costs and potential pollution issues. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Organic-rich mudstone   Black shale   Ichnology   Microbioturbation   Petrography   Paleoredox  

摘要： The Hare Indian and Canol Formations, which are part of the Horn River Group in the Northwest Territories, Canada, primarily consist of organic-rich mudstones deposited during the Middle to Late Devonian. The formations were previously considered to represent marine basin fill accumulated in an oxygen-starved distal shelf setting, evidenced by the organic-rich character, pyrite content, and lack of macro-scale bioturbation. The depositional model, paleo-oxygenation interpretations, and methods of organic carbon preservation presented in this study are in contrast to previous assumptions of the Horn River Group mudstones. Detailed petrographic, sedimentological, and ichnological analyses were carried out on thin sections taken from several cored Horn River Group intervals. These organic-rich mudstone units contain eight distinct microfacies, representing four main sedimentation processes acting on an interpreted distal shelf setting: (1) pelagic suspension settling, (2) plug-like sediment-gravity flows, (3) surge and surge-like low-density turbidity currents, and (4) debrites. Pelagic suspension-settling dominated in distal, quiet waters out of the reach of persistent storm influence. Debrites, plug-like flows, and low-density turbidite processes represent a continuum, wherein storm influence was the dominant driver in sediment delivery. Several morphologically distinct, microscopic biogenic-sedimentary structures (i.e. ichnofossils) have been identified throughout the mudstone intervals, indicative of sediment pore waters that were at least periodically partially oxygenated. Evaluation of total organic carbon content against bioturbation and microfacies interpretation suggest that persistent anoxia was not the dominant factor in organic carbon preservation, but rather a result of a combination of heightened sedimentation and burial rates and possible amplified rates of primary productivity. The results of this study may be applied to evaluations of other organic ric

关键词： Imines   Optical sensors   Metal ions   Aqueous medium   DFT calculations   Smart design  

摘要： In this work, chemical mechanic synthesis of six imines is reported, chemical structure and optical characterization is described. The imines 3a-3f were evaluated as colorimetric chemical sensors of metals: Ba2+, Co2+, Fe2+, Mg2+, Ni2+, Pb2+, Zn2+, Cd2+, Hg2+, Cu2+, Sn2+ and Cs+ where 3e being a highly selective colorimetric chemical sensor for Cu2+. The limit detection of the sensor was determined through the titration, which turned out to be 4.9 x 10(-6) M with a Ka of 8.264 x 10(3) M-1. Also, the interference of detection in a mixture of metals was studied. Finally, by the use of IR, NMR, and DFT calculations, the structure of the 3e + M complex formed, and the phenomenon responsible for the color change was determined. Finally, a possible relationship between the selectivity to metal ions and the HOMO energy levels of the molecules is proposed, being a basis for the design of smart organic sensors (C) 2020 Elsevier B.V. All rights reserved.

关键词： Phenolic compounds   Antioxidants   Antimicrobial activity   Emulsion gels   Physico-chemical properties   Lipid structure  

摘要： This article evaluates the use of emulsion gels (EGs) containing two different solid polyphenol extracts [from grape seed (R-EPG) or grape seed and olive (R-EPGO)] as animal fat replacers in the development of frankfurters. The incorporation of EGs improved their lipid content, particularly R-EPG and R-EPGO also contained high levels of phenolic compounds (hydroxytyrosol and flavanols). These frankfurters were judged acceptable by the panellists and showed good thermal and storage stability. Colour parameters, pH and textural properties were affected (p < 0.05) by the formulation, being significant the influence of polyphenols extracts. Spectroscopic results showed greater (p < 0.05) interand intramolecular lipid disorder in the frankfurters with EGs, irrespective of the presence of polyphenol extracts. Comparing the reduced-fat samples, R-EPG and R-EPGO showed the lowest (p < 0.05) total viable counts. Significant changes in pH and texture parameters were observed during chilled storage while lipid structure was not affected.

关键词： Mesoporous silica nanoparticles   Biological barriers   Physicochemical parameters   Structure-bioactivity-biosafety relationships   Surface modification strategy  

摘要： Mesoporous silica nanoparticles (MSNs) with remarkable structural features have been proven to be an excellent platform for the delivery of therapeutic molecules. Biological barriers in various forms (e.g., mucosal barrier, cellular barrier, gastrointestinal barrier, blood-brain barrier, and blood-tumor barrier) present substantial obstacles for MSNs. The physicochemical parameters of MSNs are known to be effective and tunable not only for load and release of therapeutic molecules but also for their biological responsiveness that is beneficial for cells and tissues. This review innovatively provides a description of how and why physicochemical properties (e.g., particle size, morphology, surface charge, hydrophilichydrophobic property, and surface modification) of MSNs influence their ability to cross the biological barriers prior to reaching targeted sites. First, the structural and physiological features of biological barriers are outlined. Next, the recent progresses in the critical physicochemical parameters of MSNs are highlighted from physicochemical and biological aspects. Surface modification, as an important strategy for achieving rapid transport, is also reviewed with special attention to the latest findings of bioactive groups and molecular mechanisms. Furthermore, advanced designs of multifunction intelligent MSNs to surmount the blood-tumor barrier and to actively target tumor sites are demonstrated in detail. Lastly, the biodegradability and toxicity of MSNs are evaluated. With perspectives for their potential application and biosafety, the clues in summary might lead to drug delivery with high efficiency and provide useful knowledge for rational design of nanomaterials. Statement of significance Mesoporous silica nanoparticles (MSNs) with remarkable structural features have been proven to be an excellent platform for drug delivery. However, biological barriers in various forms (e.g., mucosal barrier, cellular barrier, gastrointestinal barrier, blood-b

关键词： water stress   high temperature   starch granule size   molecular structure   pasting viscosity   retrogradation  

摘要： BACKGROUND Maize is frequently subjected to simultaneous water (drought or waterlogging) and heat (HS) stresses during grain formation in southern China. This work examined the effect of high temperature combined with drought (HD) or waterlogging (HW) during grain formation on the starch physicochemical properties of two waxy maize hybrids, namely Suyunnuo5 (SYN5) and Yunuo7 (YN7). RESULTS Heat stress enlarged the starch granule size, and water stresses aggravated this effect. Heat stress reduced the ratio of small molecular weight fractions for both hybrids, and HD aggravated this reduction only in SYN5. Relative crystallinity in SYN5 was increased by stresses but in YN7 it was unaffected by HD, reduced by HS, and increased by HW. Fourier-transform infrared (FTIR) spectrometry results showed that the 1045/1022 cm(-1)ratio in SYN5 was not influenced by HW but was increased by other stresses, and that in YN7 it was increased by all stresses, with the highest value induced by HW. Peak viscosity was decreased, whereas gelatinization temperatures and retrogradation percentage were increased by all of these stresses. These effects were exacerbated by combined heat and water stresses. The maximum decomposition rate was severely increased by HW. CONCLUSION Drought or waterlogging at grain formation stage aggravated the detrimental effects of HS on the starch physicochemical properties of waxy maize. (c) 2020 Society of Chemical Industry

关键词： Nucleic acid bases   Apparent molar properties   Hydration number   Viscosity B-coefficients  

摘要： Physicochemical studies have been carried out of some nucleic acid bases (uracil, thymine and adenine) in aqueous and mixed aqueous inositol (0.1, 0.2 and 0.3 mol kg(-1)) solutions at six different temperatures (293.15, 298.15, 303.15, 308.15, 313.15, 318.15) K. Bymeans of density, speed of sound and viscosity values, various volumetric, compressibility and viscometric parameters like apparent molar properties (V-phi, K-phi,K-s), limiting apparent molar properties (V-phi(0), K-phi,s(0)), transfer properties (Delta V-tr(phi)0, Delta K-tr(phi,s)0 and Delta B-tr), hydration number (n(H)) etc. were computed. By using Jones-Dole equation, viscosities B-coefficients have been calculated. Solvation behavior of above mentioned nucleic acid bases in aqueous solutions of inositol has also been evaluated. Using cosphere overlap model, various intermolecular interactions prevailing in the ternary systems have been discussed. By making use of the temperature derivative of B coefficient (dB/dT), the structure making/breaking of solute have been investigated. (C) 2020 Elsevier B.V. All rights reserved.

关键词： restructured fish products   citric acid   texture   tilapia  

摘要： BACKGROUND The growing consumer demand for healthy products has encouraged the development of low-salt meat products. In this study, to develop low-salt restructured tilapia (Oreochromis mossambicus) meat products, citric acid was used to improve the properties of restructured tilapia products. RESULTS In comparison with control restructured fish products (RP) and surimi products (SP), 0.2% citric acid-treated restructured fish products (RPC) and surimi products (SPC) showed a significant decrease in expressible water and water activity and a remarkable increase in whiteness, dry matter, hardness, chewiness, gumminess, and acceptability. Mechanistic studies suggested that citric acid significantly changed the content of total protein and myofibrillar proteins and promoted degradation of heavy myosin chains. Fourier-transform infrared and Raman spectra revealed the citric acid-mediated alteration in the peak intensities of amide I and amide II bands, which changed the secondary structures of RPC and SPC. CONCLUSION It is feasible to prepare low-salt restructured tilapia meat products using citric acid, which offers a means of using muscle by-products and exploiting new functional products with an added commercial value. (c) 2020 Society of Chemical Industry

关键词： Porous carbon materials   Thermal regeneration   Physicochemical properties   SO2 adsorption  

摘要： Porous carbon materials have emerged as a new technology with tremendous potential as energy-saving and environmentally friendly pathways for SO2 removal due to its advantages, which include recyclability and a high adsorption capacity. However, the degradation of the performance of adsorbents using thermal regeneration has become a key issue limiting the scaling-up of this new technology. The main purpose of this study is to clarify the effect of the regeneration temperature on the physicochemical properties of activated coke and secondary SO2 removal performance, as well as explore the mechanism by which the circulating adsorbent is deactivated. Using powdered activated coke (PAC) prepared from coal. Experimental results show that adsorbed SO2 desorbs at temperatures between 200 and 500 degrees C, while both excess CO2 and CO are released over a wide temperature range owing to the regeneration reaction and decomposition of newly formed oxygen-containing functional groups. The physicochemical properties of PAC are significantly affected by the regeneration temperature. As this temperature rises, the adsorbed sulfuric acid in the pores evaporates and the functional groups decompose, producing several micropores and a large specific surface area. Moreover, the SO2 adsorption-desorption process increases the number of C-O groups such that the active adsorption sites are occupied and SO2 adsorption is prevented. The C-O groups decompose to produce CO2 when exposed to even higher temperatures. The secondary SO2 adsorption experiment demonstrated that the ability of the adsorbent to perform desulfurization could be recovered completely by controlling the regeneration temperature.

关键词： Calcium phosphate cements   Brushite   Zinc   FTIR   PXRD   SEM  

摘要： Dicalcium phosphate dihydrate (DCPD) enriched by different amounts of Zn2+ ions was synthesised in aqueous solution via standard precipitation method. The obtained powders were characterised by powder X-ray diffractometry (PXRD), infrared spectroscopy (FT-IR), solid-state nuclear magnetic resonance (ssNMR), inductively coupled plasma optical emission spectroscopy (ICP-OES) and scanning electron microscopy (SEM). These tests confirmed that all the powders were highly microcrystalline brushite. As the concentration of zinc increased, an additional crystalline phase of alpha-hopeite appeared, and, simultaneously, the crystallinity of brushite slightly decreased. Moreover, according to the shifts of PXRD, FTIR and P-31 ssNMR line positions, it was proved that zinc ions were successfully introduced into the crystal of DCPD. The (Ca + Zn)/P molar ratio calculated from ICP-OES results was ca. 1.0, which is typical for DCPD;only the (Ca + Zn)/P molar ratio of the sample with the highest concentration of Zn slightly differs, which was caused by the presence of alpha-hopeite. SEM images have shown a high tendency of Zn-containing brushite to agglomerate into the spherical, compact clusters. The preliminary biological tests have shown that the powders are non-toxic, which makes them promising materials for potential use in mineralised tissue engineering.