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关键词： Nanopesticides   Plant protection products (PPPs)   Manufactured nanomaterials (MNMs)   Physico-chemical characterization  

摘要： The recent application of manufactured nanomaterials (MNMs) in plant protection products (PPPs) enhances stability of the active substance (a.s.), minimizes application losses, reduces the quantities of a.s., increases coverage on leaf surface, improves precise application, etc. Besides offering benefits, there is high concern about the potential risk for human and environment associated with the use of nanopesticides. In this study, a panel of complementary methodologies were used to determine size distribution and chemical identification of four different formulations of nanopesticides. Measurements were performed by dynamic light scattering (DLS), transmission electron microscopy (TEM), asymmetric field flow fractionation-multi angle light scattering (AF4-FFF-MALS), gas/liquid chromatography with mass spectrometry (GC-MS/MS, LC-MS/MS) or diode array detector (HPLC-DAD) and inductively coupled plasma mass spectrometry (ICP-MS). Results indicated average size values in the ranges: 27.4-148.7 nm by DLS;39.1-82.0 nm by AF4-FFF-MALS;and 42-90 nm by TEM. Linked to these nanosized particles both organic active ingredients and inorganic ones were identified. In addition, the obtained data revealed that all the four PPPs contained more than 50% of particles with number size distribution between 1 and 100 nm and, according to the European Commission definition, they can be defined as nanopesticides.

关键词： fluorite and barite deposits   fluid inclusions   physicochemical parameters   volatile components  

摘要： Authors' original continuously updated database, which currently comprises data from 22 300 publications on mineral-hosted fluid and melt inclusions, is used to generalize data on the physicochemical parameters of processes that produced fluorite and barite deposits. The paper presents data on the following parameters of the fluids: temperature, pressure, density, salinity, and gas composition. The average composition (H2O, CO2, CH4, N-2, H2S, and CnHm) of fluids at fluorite-barite deposits is calculated. The paper reports the average composition of major gas components (CO2, CH4, N-2, and H2S) of natural fluids at these deposits on the basis of Raman spectroscopic analyses of individual inclusions. Average F, S, and Ba concentrations are calculated for silicate magmatic melts and natural mineral-forming fluids.

关键词： phytochemical screening   chromatographic profile   sodium carboxymethylcellulose   biopolymer   allergenic activity   anti-staphylococcal   biopolymer  

摘要： The main objectives of this study were to evaluate the chemical constitution and allergenic potential of red propolis extract (RPE). They were evaluated, using high performance liquid chromatography (HPLC) and the release of beta-hexosaminidase, respectively. A plethora of biologically active polyphenols and the absence of allergic responses were evinced. RPE inhibited the release of beta-hexosaminidase, suggesting that the extract does not stimulate allergic responses. Additionally, the physicochemical properties and antibacterial activity of hydrogel membranes loaded with RPE were analyzed. Bio-polymeric hydrogel membranes (M) were obtained using 5% carboxymethylcellulose (M1 and M2), 1.0% of citric acid (M3) and 10% RPE (for all). Their characterization was performed using thermal analysis, Fourier transform infrared (FTIR), total phenolic content, phenol release test and, antioxidant activity through 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and Ferric Reducing Antioxidant Power (FRAP). The latter appointed to the similar antioxidant capacity of the M1, M2 and M3. The degradation profiles showed higher thermostability to M3, followed by M2 and M1. The incorporation of RPE into the matrices and the crosslinking of M3 were evinced by FTIR. There were differences in the release of phenolic compounds, with a higher release related to M1 and lower in the strongly crosslinked M3. The degradation profiles showed higher thermostability to M3, followed by M2 and M1. The antibacterial activity of the membranes was determined using the disc diffusion assay, in comparison with controls, obtained in the same way, without RPE. The membranes elicited antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis, with superior performance over M3. The hydrogel membranes loaded with RPE promote a physical barrier against bacterial skin infections and may be applied in the wound healing process.

关键词： Memantine   Amino acids   Alzheimer’   s disease  

摘要： Drug compounds including memantine moieties are an important group of biologically active agents for different pathologies, including the Alzheimer's disease. In the present study, a series of memantine derivatives incorporating amino acid residues have been synthesized and their neuroprotective in vitro evaluation in respect of the Alzheimer's disease, involving the effects on the resistance to A beta toxicity, excitotoxicity, oxidative stress, hypoxia, and neuroinflammation has been studied. The cytotoxicities of the compounds were detected by CPE assay. TC50 and IC50 were determined using Reed and Muench method. Solubility and distribution were measured using a shake-flask method. Permeability of the compounds was studied using Franz diffusion cell and Permeapad (TM) barrier. These compounds displayed apparent multi-neuroprotective effects against copper-triggered A beta toxicity, glutamate-induced excitotoxicity, and oxidative and hypoxic injuries. They also showed the ability to inhibit the inflammatory cytokine release from the activated microglia and potential anti-neuroinflammatory effects. Especially, two most promising compounds H-4-F-Phe-memantine and H-Tyr-memantine demonstrated the equivalent functional bioactivities in comparison with the positive control memantine hydrochloride. Higher solubility in muriatic buffer than in phosphate buffer was detected. The distribution coefficients showed the optimal lipophilicity for compounds. The presented results propose new class of memantine derivatives as potential drug compounds. Based on the experimental results, the correlations have been obtained between the biological, physicochemical parameters and structural descriptors. The correlation equations have been proposed to predict the properties of new memantine derivatives knowing only the structural formula.

关键词： In-situ TEM   Microreactor   Structure-property relationship   Physicochemical parameter   Nanomorphology   Microcantilever  

摘要： In-situ quantitative structure-property relationship (QSPR) characterization between nanomorphology and physicochemical parameters is essential for revealing the growth mechanism and guiding the optimization of functional nanomaterials. However, extracting the interrelated physicochemical parameters in the process of nanomorphology observation is still challenging. Herein, this paper demonstrates an advanced chip-scale platform for in-situ QSPR characterization by integrating a gravimetric resonant microcantilever sensor within a transmission electron microscopy (TEM) microreactor. The microcantilever measures the thermodynamic and kinetic parameters, such as enthalpy (Delta H degrees), activation energy (E-a) and reaction rate (v), by monitoring the reaction-induced mass change of functional nanomaterials. Simultaneously, the low-stress SiNx films as electron transparent windows allow in-situ nanomorphology observation. Using such a QSPR characterization platform, the three-stage sulfuration mechanism based on nano Kirkendall effect for the gas-solid reaction of H2S and Cu nanowires is revealed, and the different molecule-interaction behaviors of SO2 on ZnO nanowires at various temperatures are distinguished for the first time. It is believed that the in-situ QSPR microreactor can be widely used for elucidating the underlying interfacial thermodynamic/kinetic reaction mechanism, and guiding the controllable synthesis and precise optimization of functional nanomaterials. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Biochar   Multivariate analysis   Proximate analysis   Stability   Tea pruning litters   Ultimate analysis  

摘要： The present study aimed to optimize the production of biochar from tea (Camellia sinensis L.) pruning litter. Characterization of biochar prepared from four tea pruning litters (mixed, Tocklai Vegetative 1, 22 and 25) at five pyrolysis temperatures (250, 300, 350, 400, 450, and 500 degrees C for 3 h) were documented. The results demonstrated that yield, total nitrogen, H:C, and O:C decreased steadily with increasing pyrolysis temperature. However, water holding capacity, ash content, fixed carbon, C:N, NH4+-N, NO3--N, trace elements, total P and K, and germination index increased consistently with increasing pyrolysis temperature. All the prepared biochars are suitable for agriculture application as H:C and O:C ratios of prepared biochars are < 0.6 and < 0.4, respectively. Low pyrolysis temperature (300 degrees C) was optimal to get more stable biochar with respect to essential nutrients. Biochar derived from Tocklai Vegetative 1 at 300 degrees C has more potential for agronomic applications. Principal component analysis showed 96% variability.

关键词： Crop rotation   Diversity   Free-living nematodes   Sustainability   Triple rice  

摘要： Long-term intensive rice monoculture, triple rice cultivation (rice crops are cultivated three times per year) in the Mekong Delta, Vietnam, causes a reduction in topsoil quality. Rotating rice with an upland crop in a tropical paddy field may improve the soil physicochemical properties but effects on the soil nematode community are unknown. This study was conducted in a triple rice field to evaluate the responses of the nematode community to a crop rotation (the first rice in a year was replaced with sesame and soybean, and the second and third crops were rice) and to organic amendment. The experiment was based on a split-plot design with two factors that were crops (main factor, n = 3) and compost amendment (sub-factor, n = 3). The crops were rice, soybean, and sesame and the sub-factors were cow manure plus rice straw compost, sugarcane compost, and no amendment. Soil samples were taken at harvest of the first crops in topsoil (0-10 cm) and subsoil (10-20 cm) in 2017 and 2018. In 2018, the abundance of free-living nematodes (FLN), which were dominated by bacterivores and fungivores, was greater in upland crops, while that of plant-parasitic nematodes (PPN) was greater in paddy rice. In particular, the density of the most predominant PPN genus, Hirschmanniella, was lower in upland crops than in paddy rice. Cultivation of sesame also reduced the number of the second predominant PPN genus, Bitylenchus, resulted in an increase in the ratio of the free-living to plant-parasitic nematodes. The diversity evenness index (J), Shannon-Wiener (H') and Hill's indices increased in upland crops compared to those in rice fields in 2018. Crop rotation with sesame or soybean in a paddy field enhanced abundance and biodiversity of FLN and suppressed PPN and thus can be proposed for agricultural sustainability.

关键词： Ionogels   Halloysite   Ionic liquids   Structural characteristics   Thermal destruction   Ionic conductivity  

摘要： This work is the first attempt to study the physicochemical properties of ionogels - quasi-solid hybrid materials formed by ionic liquids (ILs) - 1-butyl-3-methylimidazolium (BMIm(+)) salts with dicyanamide- (DCA-), bis(trifluoromethylsulfonyl)imide- (TFSI-), and trifluoromethanesulfonate- (Otf(-)) anions - and halloysite, a powdered clay filler with nanotube particles (at the IL:Hal molar ratio of 2:1) in order to find possible new applications of ionic liquids and industrial minerals. The electron microscopy, TG, and DSC analysis, FTIR spectroscopy, X-ray diffraction analysis, conductometry and cyclic voltammetry methods are used to investigate the anion effect on the IL interaction with halloysite. It has, for the first time, been found that the distinguishing feature of halloysite interaction with an IL determining the structural changes in the clay mineral and electrochemical characteristics of the ionogels is partial dehydration of the clay and absorption of the released water by the ionic liquid. It is shown that the halloysite dehydration effect depends on the IL hydrophilicity determined by the anion type, corresponds to the series: BMImDCA > BMImOtf > BMImTFSI. The electrochemical and thermal behaviour of ILs confined within a halloysite matrix differs from that of bulk ILs and is controlled by the anion type. Temperature dependences of the structural resistance of the halloysite filler are radically different for the ILs with high and low hydrophilicity. The effects resulting from the formation of halloysite-based ionogels can be of interest to those who develop quasi-solid ionic conductors that can work within a wide temperature range. (C) 2020 Published by Elsevier B.V. on behalf of King Saud University.

关键词： Biomass   Hardwood   Organosolv lignin   Kraft lignin   Characterization  

摘要： The heterogeneity and complexity of lignin necessitate a deep understanding to select the most appropriate lignin valorization and convert it into value-added products. The objective of this research is to investigate the features of organosolv and Kraft lignins, in order to understand the effects of the sources and the isolation treatment, through the comparison of physicochemical and thermal properties. Various techniques have been employed such us Fourier transform infrared spectroscopy (FTIR), carbon solid state nuclear magnetic resonance (CNMR)-C-13, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. It was found that lignin produced from the hardwood using the Kraft process provided the greatest yield compared to other combinations. Softwood pretreatments achieve almost higher sugar yield than hardwood treatments. The infrared spectroscopy analysis confirms the existence of different monolignols. Organosolv lignins showed a predominance of guaiacyl and syringyl units. To provide additional information, the principle components analysis, as a powerful chemometric method, has also been applied to evaluate the FTIR data. NMR spectroscopy of lignins demonstrated the presence of essential functional chemical groups. It is also revealed that the nature of the treatment and the source of lignin samples affect the thermal properties. Overall, lignin isolated from Aleppo pine using Kraft process presented better thermal stability than that of organosolv lignin. [GRAPHICS] .

关键词： Surface roughness  

摘要： Permeate flux, solute rejection, membrane fouling and permeate flux recovery in ultrafiltration (UF) acid bovine cheese whey was investigated for RC70PP (regenerated cellulose acetate), ETNA10PP (composite fluoro polymer) and GR73PP (polyethersulphone) commercial UF membranes (all 10 kDa nominal pore size). Pore morphology dominantly affected water permeability;active layer porosity affected intrinsic membrane resistance. Membrane roughness was the main factor in irreversible fouling resistance;the high roughness of ETNA10PP increased the rejection of the common whey proteins and lactose. A positive surface free energy of interaction of RC70PP resulted in comparable low fouling propensity regardless of the zeta-potential. The surface charge of two hydrophobic membranes (ETNA10PP and GR73PP) significantly affected fouling resistance. The recovery ratio of initial permeate flux after cleaning was directly related to the membrane hydrophilicity. The RC70PP membrane offered much better efficiency for the concentration of whey proteins due to its high antifouling performance despite its poor selectivity. (C) 2020 Elsevier Ltd. All rights reserved.