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关键词： TiO2(B)   SAED pattern analysis   Arsenic adsorption   Site energy distribution   DFT calculations  

摘要： In this study, iron-doped TiO2(B) nanoribbons (Fe-TiO2(B) NR) have been synthesized using the anatase TiO2 as a precursor. The formation of TiO2(B) with the monoclinic crystal system was confirmed by HRTEM, SAED pattern, and XRD analyses. The ESR and XPS analyses further revealed the presence of Ti3+ and oxygen vacancies in Fe-TiO2(B) NR. The Fe-TiO2(B) NR, as an adsorbent, exhibited a fantastic performance in adsorbing As(III) from potable water at near-neutral pH. More than 94% of removal efficacy was observed for all the studied As(III) concentrations (50, 100, 250, 500, 750, and 1000 ppb) at 1 g L-1 dose at 30, 40, and 50 degrees C temperatures in dark condition. Irradiation with visible light, however, diminished the removal efficacy to similar to 88%. The Sips, the Toth, and the D-A isotherm model-based approximate site energy distributions had taken the unimodal quasi-normal distribution pattern. Nevertheless, the density functional theory (DFT) calculations showed that the adsorption of H3AsO3 is highly favourable on the (001) crystal plane of monoclinic TiO2(B). Moreover, the DFT calculations meticulously suggested the exothermic nature of the adsorption process and the chances of oxidation of H3AsO3 on the (001) crystal plane of monoclinic TiO2(B), which was further vindicated by XPS analysis. (c) 2020 Elsevier B.V. All rights reserved.

关键词： Hen egg white lysozyme   Triton X-100   Methimazole   Fibrillation inhibition   Calorimetry   Fluorescence spectroscopy  

摘要： Identification of functionalities responsible for prevention of fibrillation in proteins is important to design effective drugs in addressing neurodegenerative diseases. We have used nonionic surfactant triton X-100 (TX-100) and antithyroid drug methimazole (MMI) to understand mechanistic aspects of action of these molecules having different functionalities on hen egg-white lysozyme at different stages of fibrillation. After establishing the nucleation, elongation and maturation stages of fibrillation of protein at 57 degrees C, energetics of interactions with these molecules have been determined by using isothermal titration calorimetry. Differential scanning calorimetry has permitted assessment of thermal stability of the protein at these stages, with or without these molecular entities. The enthalpies of interaction of TX-100 and MMI with protein fibrils suggest importance of hydrogen bonding and polar interactions in their effectiveness towards prevention of fibrils. TX-100, in spite of several polar centres, is unable to prevent fibrillation, rather it promotes. MMI is able to establish polar interactions with interacting strands of the protein and disintegrate fibrils. A rigorous comparison with inhibitors reported in literature highlights importance -OH and >CO functionalities in fibrillation prevention. Even though MMI has hydrogen bonding centres, its efficiency as inhibitor falls after the inhibited lysozyme fibrils further interact and form amorphous aggregates. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Ionic liquids   Catanionics   Symmetric quaternary ammonium cations   Alkyl ether cartoxlate anions  

摘要： Thirty-nine different Ionic Liquids were synthesized, with symmetric quaternary ammonium cations and alkylethercarboxylates as anions. Similar to the recently published Concept of Melting Point Lowering due to Ethoxylation, here propoxyethylene groups, PO groups, in the anions allow a wide range of salts being liquid at or dose to room temperature. The physical chemical properties, density, viscosity, conductivity, thermal stability, melting behaviour and hygroscopy of such Ionic Liquids were determined. Density was linearly dependent on the temperature and was affected by the molecular weight of the Ionic Liquid. Higher viscosity of longer carbon chains resulted from stronger intermolecular Van der Waals forces. Viscosity of the Ionic Liquids was lowered by shorter carbon chains in the anions, bulkier cations or lower propoxyethylene degrees. The conductivity of the Ionic Liquids ranged from 1 to 3000 mu S/cm and was dependent on the structure of the compound. Melting points of Ionic Liquids were dependent on the length of the carbon chain. At high temperatures, they decomposed in a two-step mechanism. First, the cationic part decomposed, and, at a higher temperature, the anionic part of the Ionic Liquid. Moreover, the Ionic Liquids showed a strong hygroscopic behaviour that was observed for an extended time range up to 5 days. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Anionic dyes   Multilayer adsorption   Lignocellulosic biomasses   Adsorption mechanism  

摘要： This paper reports the physicochemical analysis of the multilayer adsorption of anionic dyes on lignocellulosic biomasses. Experimental studies, statistical physics modeling and density functional theory (DFT) calculations were carried out to understand and characterize the adsorption mechanism of dyes Acid Blue 29, Acid Blue 113 and Reactive Blue 4 using coconut shells, cauliflower cores and broccoli stalks as low-cost adsorbents. Steric parameters and adsorption energies were estimated from an advanced multilayer statistical physics model and these parameters were associated with the biomass composition and dye molecular properties. DFT calculations were also performed to characterize the atomic interactions of dye molecules and surface functionalities from the main biopolymers contained in the lignocellulosic biomasses. Results showed that the multilayer adsorption of these anionic dyes was related to the cellulose contained in these biomasses where the best adsorption capacities were obtained for cauliflower cores with a cellulose composition of 11.2%. It was also confirmed that the dye aggregation played an important role for the removal of these adsorbates where cluster formation was significantly affected by adsorption temperature. Hydrogen bonding was the main interaction for the endothermic dye adsorption using these biomasses. Results reported in this paper contribute to understand the dye adsorption mechanism using low-cost adsorbents like lignocellulosic materials with the aim of improving the performance of treatment technologies for water decolorization. (c) 2020 Elsevier B.V. All rights reserved.

关键词： Nitrogen-doped carbon   Pyrolytic carbon   Mesoporous carbon   Li-ion batteries   Na-ion batteries  

摘要： A series of N-doped mesoporous carbon (NMC) materials are synthesized by the co-pyrolysis of an N-containing compound and carbon sources using a modified nanocasting method. The physicochemical properties are manipulated by changing the amount of resol precursors to permit the usage of these materials in the desired applications. As anodes for Li-ion batteries, the prepared NMC2, which has the highest number of hydrogenated N functional groups, delivers a high discharge capacity of 900, 700, and 600 mAh g(-1) at current densities of 0.5, 1, and 2 A g(-1), respectively, after 200 cycles of discharging and charging. Even at an extremely high current density of 10 A g(-1), the NMC2 electrode delivers a discharge capacity of 300 mA g(-1). In addition, in Na-ion batteries, NMC3, which has the highest pyridinic N content and average pore diameters, exhibits a discharge capacity of 163 mAh g(-1) at 1 A g(-1) over 500 cycles. Hence, an intimate relationship between the key physicochemical parameters and electrochemical properties of NMC materials are established for use of these materials in specific applications. The obtained results demonstrate that the fabricated NMC materials possess superior characteristics in comparison to those of most state-of-the-art porous carbon materials. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Nanocolloids   Isentropic compressibility   Acoustic impedance   Surface engineering   Stability  

摘要： FRSA (free radical scavenging activity) of antioxidant polyphenols (APP) capped ZnO NPs is tuned with TTDMM (trimesoyl tridimethyl malonate) interfaces in *** by modulating undesired effect of DMSO. Such action occurs on interlocuting hydrophobic and hydrophobic interactions of -CH3 groups (DMSO) with 6 terminal -CH3 groups of TTDMM tweezer respectively. The studies are supported with physiochemical contour of APP capped ZnO (c-ZnO) and c-ZnO NPs loaded TTDMM nanocomposites (cZTNCs) dispersed in aqueous (aq.) and aq. DMSO respectively to form nanocolloids. Intermolecular interactions for dispersion and stability have been explored via density (rho), sound velocity (u), isentropic compressibility (K-s), acoustic impedance (Z), thermal expansion coefficient (beta), surface tension (gamma), viscosity (eta), friccohesity (sigma), light velocity (C) and refractive index (mu(ri)) from (298.15 to 313.15) K. The values of these structural parameters infer the impacts of APP and TTDMM on surface reengineering of nanocolloids via philicphobic domain, London dispersive forces (LDF), van der Waals forces (VWF), and hydrogen bond (HB). Besides this, the nanocolloids are not getting destructured but monodispersed and were analyzed through the said physiochemical parameters. FTIR stretching frequencies (SF) of nanocolloids have synchronized their intermolecular interactions with the surrounding medium. The unaltered surface plasmon resonance (SPR) peak for cZTNC nanocolloids inferred stability via UV/Vis spectra The moderate negative values for Gibbs energy (Delta G), enthalpy (Delta H),entropy (Delta S), and positive activation energy (E-a) with least K-s have inferred thermodynamically and kinetically (TAK) stable cZTNC nanocolloids as the void spaces of TTDMM tweezer entrap c-ZnO NPs to a specific orientation. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Hexavalent chromium   Water pollution   Chemical reduction   Metal nanoparticles   Nanocatalysis  

摘要： Hexavalent Chromium [Cr(VI)] is a highly carcinogenic and toxic material. It is one of the major environmental contaminants in aquatic system. Its removal from aqueous medium is a subject of current research. Various technologies like adsorption, membrane filtration, solvent extraction, coagulation, biological treatment, ion exchange and chemical reduction for removal of Cr(VI) from waste water have been developed. But chemical reduction of Cr(VI) to Cr(III) has attracted a lot of interest in the past few years because, the reduction product [Cr(III)] is one of the essential nutrients for organisms. Various nanoparticles based systems have been designed for conversion of Cr(VI) into Cr(III) which have not been critically reviewed in literature. This review present recent research progress of classification, designing and characterization of various inorganic nanoparticles re-ported as catalysts/reductants for rapid conversion of Cr(VI) into Cr(III) in aqueous medium. Kinetics and mechanism of nanoparticles enhanced/catalyzed reduction of Cr(VI) and factors affecting the reduction process have been discussed critically. Personal future insights have been also predicted for further development in this area.

关键词： Chitosan   Chitosan production   The degree of deacetylation   Chitosan physicochemical properties   Chitosan nanofibers   Bioprinting  

摘要： Recent advancements in the synthesis, properties, and applications of chitosan as the second after cellulose available biopolymer in nature were discussed in this review. A general overview of processing and production procedures from A to Z was highlighted. Chitosan exists in three polymorphic forms which differ in degree of crystallinity (alpha,beta, and gamma). Thus, the degree of deacetylation, crystallinity, surface area, andmolecular mass significantly affect most applications. Otherwise, the synthesis of chitosan nanofibers is suffering from many drawbacks that were recently treated by co-electrospun with other polymers such as polyvinyl alcohol (PVA), polyethylene oxide (PEO), and polycaprolactone (PCL). Ultimately, this review focuses on the area of new trend utilization of chitosan nanoparticles as nanospheres and nanocapsules, in cartilage and bone regenerative medicine. Owing to its biocompatibility, bioavailability, biodegradability, and costless synthesis, chitosan is a promising biopolymeric structure for water remediation, drug delivery, antimicrobials, and tissue engineering. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Chitosan  

摘要： In the global context of emerging pathogens associated with respiratory diseases, novel nanostructured lipid carriers (NLCs) having both antioxidant and antimicrobial properties produced by alpha-tocopherol (alpha T) and levofloxacin (LV), respectively, were developed. The hybrid NLCs were made of solid lipid esters and liquid alpha T as the central core, plus chitosan (Chi) and poloxamer 188 as surface stabilizers. Three formulations were rationally designed considering lipids with different physicochemical properties: cetyl ester (SS), glyceryl dibehenate (CO) and glyceryl tristearate (DY). The properties and stability of the nanoformulations were studied by dynamic light scattering considering the effects of the homogenization time, surfactant concentration, and initial lipid amount on the mean size, polydispersity index (PDI) and zeta potential of the nanoparticles. The effect of alpha T on the nanostructuration of the lipid matrix was demonstrated by X-ray diffraction, differential scanning calorimetry, and thermogravimetry analysis. The potential ability of the NLCs to interact with the mucosa was studied by rheological methods, demonstrating a reduction in mucin cohesiveness and elasticity due to the mucoadhesive properties of NLCs coated with chitosan. Solid lipid nanoparticles (SLNs) of SS, CO and DY encapsulated 58.0 +/- 3.2, 25.7 +/- 7.1, and 27.9 +/- 1.5% LV, respectively, while the NLC formulations were able to encapsulate 80-90% LV and allowed controlled release of the drug. The enhanced antimicrobial properties of the SLNs/NLCs against Pseudomonas aeruginosa and Staphylococcus aureus were confirmed. The presence of alpha T in the formulations provided the antioxidant properties of the NLCs. Finally, no acute toxicities of the formulations were observed in two human lung cell lines (A549 and Calu-3).

关键词： Beyond rule of 5   intramolecular interaction   molecular chameleon   property-based drug design   virtual event  

摘要： An increasing number of drug discovery programs concern compounds in the beyond rule of 5 (bRo5) chemical space, such as cyclic peptides, macrocycles, and degraders. Recent results show that common paradigms of property-based drug design need revision to be applied to larger and more flexible compounds. A virtual event entitled "Solubility, permeability and physico-chemical properties in the bRo5 chemical space" was organized to provide preliminary guidance on how to make the discovery of oral drugs in the bRo5 space more effective. The four speakers emphasized the importance of the bRo5 space as a source of new oral drugs and provided examples of experimental and computational methods specifically tailored for design and optimization in this chemical space.