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关键词： Dissolution kinetics   Zinc oxide   Physicochemical characterization   Bioavailability   Diffusion  

摘要： Dissolution kinetics of zinc oxide (ZnO) powders used as feed additives for supplementation in diet of animals is studied in relation to the powder physicochemical characteristics. The fundamental issue of discrimination of reaction-limited or diffusion-limited dissolution into a stirred liquid medium is addressed. Relationships between dissolution kinetics and physicochemical properties are investigated for a set of 34 ZnO samples of various origins. A principal component analysis allows sorting ZnO samples in three clusters having different physicochemical properties. A correlation analysis discloses the most relevant physicochemical characteristics affecting dissolution: density, agglomerate size and specific surface area. Coarse particles dissolve in a reaction-limited process according to their specific surface area. Fine aggregated particles dissolve in 2 steps: reaction-limited dissolution at the surface of ZnO primary particles, followed by diffusion in the quiescent liquid medium between primary particles to the stirred bulk aqueous medium. A reaction-diffusion model is proposed. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Garlic extract   Encapsulation   Whey protein isolate   Gum Arabic   Chitosan   Polydextrose  

摘要： Garlic extract (GE) was encapsulated into the matrices of two types of multilayer walls composed of whey protein isolate (WPI)/chitosan (CH)/polydextrose (POL) and gum Arabic (GA)/CH/POL. Fourier transform infrared spectroscopy (FTIR) indicated that the compounds of GE were encapsulated within the matrices of the wallmaterials by physical interactions. The water adsorption isotherms of the powders were determined at 30, 40 and 50 degrees C. The GAB model was the most suitable to fit the adsorption data. The adsorption sorption of the powders was enthalpy-controlled and the thermodynamic functions demonstrated that the WPI/CH/POL powders had hydrophilic surface with higher number of polar sites available to binding with water molecules than GA/CH/POL powders. The experimental data of water and nitrogen adsorption isotherms were used to determine the surface areas and pore sizes of the powders. All the results can be used to improve the processing, handling, and storage conditions of the powders. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Levantine rock art   Prehistoric art   Analytical chemistry   Pigments   Binders   Crusts  

摘要： This paper offers an updated review of the variety of physicochemical analysis applied so far to Levantine rock art (Spain) to characterize the composition of the pigments, as well as the substrate and/or the natural coating covering these particular prehistoric paintings. This paper is part of a broader special issue evaluating the real contribution of scientific approaches to rock art research, assessing how they have improved our understanding of this particular heritage and the new research questions they open. In this context, and with a focus on Levantine rock art, our aim is to explore: 1. The guiding principles behind the different sorts of analysis conducted and published so far;2. The non-invasive and invasive techniques applied to answer the research questions raised, and 3. If the result published as yet have met the expectations of rock art researchers. We also reflect on the potential, the limitations and the future developments of this sort of studies, as well as on the ethics and desirable protocols of applying invasive techniques to this UNESCO World Heritage listed archaeological remain. While the focus is Levantine rock art, the discussions raised by this paper and the experiences reported in relation to the various techniques used are of global interest, especially when dealing with open-air rock art.

关键词： Microplastics   Emerging contaminants   Pharmaceuticals   Physicochemical properties  

摘要： This review discusses the imminent threat that microplastics (MPs) associated with pharmaceuticals represent to the aquatic environment and public health. We initially focused upon recognizing and stressing that MPs are ubiquitous pollutants. The influence of environmental factors, such as pH, mechanical stress, and photodegradation, are examined, aiming to elucidate how both substances might associate, what are their simultaneous degradation pathways and, to understand the interactions between MPs and pharmaceuticals. Mathematical tools, such as modeling and simulations, are presented in detail, aiming to improve how information is interpreted. Furthermore, it is exhibited that MPs sorption and interaction behavior towards organic contaminants play an important role in understanding its dynamics in the environment, aswell as their possible interactionswith pharmaceuticals that are summarized. At last, MPs and pharmaceuticals toxicity and bioaccumulation are presented. (c) 2020 Elsevier B.V. All rights reserved.

关键词： Phosphovanadate glasses   Photocatalytic activity   Photocatalysis   rhodamine B   Dye  

摘要： BaO-containing glasses of Bi2O-P2O5-V2O5 are synthesized by a conventional melt-quenching method. The asprepared samples are first heat-treated at 350 degrees C overnight, and then heat-treated at 1000 degrees C for 30 min. The as-prepared samples are studied for their physicochemical properties using FTIR, SEM, and EDX analysis. A study of the as-prepared photocatalytic properties for the degradation of common organic dyes such as RhB under UV light is carried out. The highest rate of degradation (70%) is observed when a Bi((0.5-y))BayP((0.25-0.5y))V((0)(.75)(-0.5)(y))O-4.5(-3)y catalyst with y = 0.1 was used. This sample maintains high photocatalytic activity after three cycles, without any significant decrease.

关键词： Cadmium(ii)   Comment   L-proline   Response  

摘要： In a recent publication, Srinivasan and Gobre [1] commented on our research findings [2] . In this letter to Editor, I wish to respond to the comments. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Canistel starch   Different drying pretreatments   Physicochemical property   Structural characterization  

摘要： This work investigated the effects of hot air drying pretreatment (HAD), freeze drying pretreatment (FD) and vacuum drying pretreatment (VD) on the physicochemical properties and structural characterizations of starch isolated from canistels. X-ray diffraction displayed that the starches separated from canistel by different drying pretreatments showed a typical A-type crystal structure. The SEM image showed that cracks and debris appeared on the surface of HVD and VD particles. The molecular structure of starches obtained by different drying pretreatments was studied using Fourier infrared and solid state C-13 CP/MAS NMR analysis. The results indicated that vacuum drying pretreatment could promote the formation of the double helix of starch granules, and hot air drying and freeze drying destroyed the ordered structure of starch granules. These structural changed to affect the physicochemical properties of starch granules. The study of different drying pretreatments to separate starches provided practical value for drying pretreatments. Furthermore, the current study affords information for canistel starches cultivated in China that would be convenient for commercial applications. (C) 2020 Published by Elsevier B.V.

关键词： Avapritinib   DFT   SERS/GERS   Self-assembly   LIE  

摘要： Avapritinib is a complex molecule with many heterocyclic rings developed for the treatment of advanced PDGFRA D842V-mutant gastrointestinal stromal tumours. The manuscripts presents the study of the structure, ground state and excited state reactivity and stability indices in different solvent atmosphere using density functional theory in B3LYP/aug-cc-pVDZ level. Different molecular properties like reactivity surface, average local ionization energy, nudear and electronic electrostatic potential, reduced density gradient assay, and localized molecular orbital analysis are studied in detail. The various intrarnolecular electron delocalisations were studied using natural orbital formalism and intermolecular interactions analysed by evaluating the extended of non-covalent interactions. Another interesting study is the enhancement in Raman activity of the compound when it forms a self-assembly with graphene quantum dots leading to SERS/GERS, which is studied by incorporating Grimme's dispersion into the previous functional. The electronic spectrum was studied in detail using time dependent density functional theory using long range corrected CAM-B3LYP functionals. The compound showed good light harvesting efficiency also. The local information entropy study provides uncertainty of electrons in spatial distribution. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Edible vegetable oils   Fatty acids   FTIR   Principal component analysis  

摘要： This work aimed to investigate and compare the composition and the physicochemical properties of 18 different sources of edible vegetable oils. A systematic study on the correlation between composition and physical properties was performed using Fourier Transform Infrared (FTIR) Spectroscopy and fatty acid chromatographic analysis. Principal component analysis of FTIR spectra is performed to classify edible oils concerning their physical properties. The results demonstrate the potentiality of the method associated with multivariate statistics analysis as powerful, fast, and non-destructive tools for characterization and quality control of edible vegetable oils. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Low-rank coal   Pyrolysis   TG-FTIR   Volatile species  

摘要： Three coal samples with different density (d < 1.35, 1.35 < d < 1.40 and d > 1.40 g cm(-3)) which were separated using ZnCl2 specific gravity liquid from Naomaohu (NMH) coal were investigated to understand the difference in their physicochemical and thermal properties. Fourier transform infrared spectrometry (FTIR), Raman, X-ray diffraction (XRD), solid-state C-13 Nuclear Magnetic Resonance (C-13 NMR) and scanning electron microscopy (SEM) methods were used to determine the physicochemical characteristics of the coal sample. In addition, a TG-FTIR analyzer was used to investigate the key thermal conversion characteristics and volatile emissions of the three coal samples. Typical volatile contents including CO2, CO, CH4, and Aromatic C=C were analyzed. Results showed that the density has great effect on functional groups and crystalline structure on coal sample. Four distinct peaks are showed in DTG curves, indicating that four reaction stages, namely, drying, desorption, pyrolysis, and polycondensation, were involved in the pyrolysis process of NMH coal. The TG/DTG curves of the three densities indicate that the low-density coal assumes the highest weight loss rate at the pyrolysis stage and the trend becomes weaker at the polycondensation stage. Two obvious emission peaks vividly showed that light gases such as CO2, CO, and CH4 can be separated into two stages at the pyrolysis and polycondensation stage.