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Microcystin-LR, a cyanotoxin, modulates division of higher plant chloroplasts through protein phosphatase inhibition and affects cyanobacterial division. CHEMOSPHERE 2024; 358:142125. [PMID: 38670509 DOI: 10.1016/j.chemosphere.2024.142125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/09/2024] [Accepted: 04/21/2024] [Indexed: 04/28/2024]
Abstract
Microcystin-LR (MC-LR) is a harmful cyanotoxin that inhibits 1 and 2A serine-threonine protein phosphatases. This study examines the influence of MC-LR on chloroplast division and the underlying mechanisms and consequences in Arabidopsis. MC-LR increased the frequency of dividing chloroplasts in hypocotyls in a time range of 1-96 h. At short-term exposures to MC-LR, small-sized chloroplasts (longitudinal diameters ≤6 μm) were more sensitive to these stimulatory effects, while both small and large chloroplasts showed stimulations at long-term exposure. After 48 h, the cyanotoxin increased the frequency of small-sized chloroplasts, indicating the stimulation of division. MC-LR inhibited protein phosphatases in whole hypocotyls and isolated chloroplasts, while it did not induce oxidative stress. We show for the first time that total cellular phosphatases play important roles in chloroplast division and that particular chloroplast phosphatases may be involved in these processes. Interestingly, MC-LR has a protective effect on cyanobacterial division during methyl-viologen (MV) treatments in Synechococcus PCC6301. MC-LR production has harmful effects on ecosystems and it may have an ancient cell division regulatory role in stressed cyanobacterial cells, the evolutionary ancestors of chloroplasts. We propose that cytoplasmic (eukaryotic) factors also contribute to the relevant effects of MC-LR in plants.
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Optimized Pt-Co Alloy Nanoparticles for Reverse Water-Gas Shift Activation of CO 2. ACS APPLIED NANO MATERIALS 2024; 7:9968-9977. [PMID: 38752020 PMCID: PMC11091851 DOI: 10.1021/acsanm.4c00111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 03/26/2024] [Accepted: 04/11/2024] [Indexed: 05/18/2024]
Abstract
Different Co contents were used to tune bimetallic Pt-Co nanoparticles with a diameter of 8 nm, resulting in Pt:Co ratios of 3.54, 1.51, and 0.96. These nanoparticles were then applied to the MCF-17 mesoporous silica support. The synthesized materials were characterized with HR-TEM, HAADF-TEM, EDX, XRD, BET, ICP-MS, in situ DRIFTS, and quasi in situ XPS techniques. The catalysts were tested in a thermally induced reverse water-gas shift reaction (CO2:H2 = 1:4) at atmospheric pressure in the 200-700 °C temperature range. All bimetallic Pt-Co particles outperformed the pure Pt benchmark catalyst. The nanoparticles with a Pt:Co ratio of 1.51 exhibited 2.6 times higher activity and increased CO selectivity by 4% at 500 °C. Experiments proved that the electron accumulation and alloying effect on the Pt-Co particles are stronger with higher Co ratios. The production of CO followed the formate reaction pathway on all catalysts due to the face-centered-cubic structure, which is similar to the Pt benchmark. It is concluded that the enhanced properties of Co culminate at a Pt:Co ratio of 1.51 because decreasing the ratio to 0.96 results in lower activity despite having more Co atoms available for the electronic interaction, resulting in the lack of electron-rich Pt sites.
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Application of Alcohols to Inhibit the Formation of Ca(II) Dodecyl Sulfate Precipitate in Aqueous Solutions. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1806. [PMID: 38673163 PMCID: PMC11051115 DOI: 10.3390/ma17081806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024]
Abstract
The presence of alkaline earth cations, in particular, Ca2+ and Mg2+ ions in brine, causes undesired effects in solutions containing anionic surfactants because of precipitate formation. In the present study, an anionic surfactant, sodium dodecyl sulfate (SDS), was investigated, focusing on the determination of various properties (surface tension, critical micelle concentration, micelle size, turbidity) in the presence of alcohols and, in particular, the inhibition of the precipitation of SDS with calcium ions. The calcium ions were added to the surfactant in increasing concentrations (3.0-10.0 g/L), and short-carbon-chain alcohols (methanol, ethanol, n-propanol and n-butanol) were used to shift the onset of precipitate formation. The critical micelle concentration (CMC) of SDS in the presence of alcohols was also determined. It was established that among these alcohols, methanol and ethanol did not exert significant effects on the solubility of the Ca(DS)2 precipitate, while n-propanol and n-butanol were found to be much more efficient inhibitors. In addition, all the alcohols in the applied concentration range (up to 20 V/V%) were found to decrease the critical micelle concentration of SDS.
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Design of Bismuth Tungstate Bi 2WO 6 Photocatalyst for Enhanced and Environmentally Friendly Organic Pollutant Degradation. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1029. [PMID: 38473501 DOI: 10.3390/ma17051029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/10/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024]
Abstract
In this study, a chemical precipitation approach was adopted to produce a photocatalyst based on bismuth tungstate Bi2WO6 for enhanced and environmentally friendly organic pollutant degradation. Various tools such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), optical spectroscopy and X-ray photoelectron spectroscopy, were employed to assess the structural and morphological properties. Hence, the XRD profiles showed a well crystallized Bi2WO6 orthorhombic phase. The photocatalytic performance of the resulting photocatalyst was assessed by the decomposition of Rhodamine B (RhB) and methyl orange (MO) with a decomposition efficiency of 97 and 92%, along with the highest chemical oxygen demand of 82 and 79% during 120 min of illumination, respectively. The principal novelty of the present work is to focus on the changes in the crystalline structure, the morphology, and the optical and the photoelectrochemical characteristics of the Bi2WO6, by tuning the annealing temperature of the designed photocatalyst. Such physicochemical property changes in the as-prepared photocatalyst will affect in turn its photocatalytic activity toward the organic pollutant decomposition. The photocatalytic mechanism was elaborated based on electrochemical impedance spectroscopy, photocurrent analysis, photoluminescence spectroscopy, and radical trapping measurements. The overall data indicate that the superoxide O2•- and holes h+ are the principal species responsible for the pollutant photodegradation.
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Pt/MnO Interface Induced Defects for High Reverse Water Gas Shift Activity. Angew Chem Int Ed Engl 2024; 63:e202317343. [PMID: 38117671 DOI: 10.1002/anie.202317343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/16/2023] [Accepted: 12/18/2023] [Indexed: 12/22/2023]
Abstract
The implementation of supported metal catalysts heavily relies on the synergistic interactions between metal nanoparticles and the material they are dispersed on. It is clear that interfacial perimeter sites have outstanding skills for turning catalytic reactions over, however, high activity and selectivity of the designed interface-induced metal distortion can also obtain catalysts for the most crucial industrial processes as evidenced in this paper. Herein, the beneficial synergy established between designed Pt nanoparticles and MnO in the course of the reverse water gas shift (RWGS) reaction resulted in a Pt/MnO catalyst having ≈10 times higher activity compared to the reference Pt/SBA-15 catalyst with >99 % CO selectivity. Under activation, a crystal assembly through the metallic Pt (110) and MnO evolved, where the plane distance differences caused a mismatched-row structure in softer Pt nanoparticles, which was identified by microscopic and surface-sensitive spectroscopic characterizations combined with density functional theory simulations. The generated edge dislocations caused the Pt lattice expansion which led to the weakening of the Pt-CO bond. Even though MnO also exhibited an adverse effect on Pt by lowering the number of exposed metal sites, rapid desorption of the linearly adsorbed CO species governed the performance of the Pt/MnO in the RWGS.
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Antimicrobial and antioxidant activity of encapsulated tea polyphenols in chitosan/alginate-coated zein nanoparticles: a possible supplement against fish pathogens in aquaculture. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:13673-13687. [PMID: 38261222 PMCID: PMC10881692 DOI: 10.1007/s11356-024-32058-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 01/14/2024] [Indexed: 01/24/2024]
Abstract
Regulation of antibiotic use in aquaculture calls for the emergence of more sustainable alternative treatments. Tea polyphenols (GTE), particularly epigallocatechin gallate (EGCG), have various biological activities. However, tea polyphenols are susceptible to degradation. In this work, EGCG and GTE were encapsulated in zein nanoparticles (ZNP) stabilized with alginate (ALG) and chitosan (CS) to reduce the degradation effect. ALG-coated ZNP and ALG/CS-coated ZNP encapsulating EGCG or GTE were obtained with a hydrodynamic size of less than 300 nm, an absolute ζ-potential value >30 mV, and an encapsulation efficiency greater than 75%. The antioxidant capacity of the encapsulated substances, although lower than that of the free ones, maintained high levels. On the other hand, the evaluation of antimicrobial activity showed greater efficiency in terms of growth inhibition for ALG/CS-ZNP formulations, with average overall values of around 60%, reaching an inhibition of more than 90% for Photobacterium damselae. These results support encapsulation as a good strategy for tea polyphenols, as it allows maintaining significant levels of antioxidant activity and increasing the potential for antimicrobial activity, in addition to increasing protection against sources of degradation.
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Nickel oxide nanoparticles induce cell wall modifications, root anatomical changes, and nitrosative signaling in ecotypes of Ni hyperaccumulator Odontarrhena lesbiaca. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122874. [PMID: 37949159 DOI: 10.1016/j.envpol.2023.122874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/22/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
The industrial application and environmental release of nickel oxide NPs (NiO NPs) is increasing, but the details of their relationship with plants are largely unknown. In this work, the cellular, tissue, organ, and molecular level responses of three ecotypes of Ni hyperaccumulator Odontarrhena lesbiaca grown in the presence of high doses of NiO NP (250 mg/L and 500 mg/L) were studied. All three ecotypes showed a similar accumulation of Ni in the presence of nano Ni, and in the case of NiO NPs, the root-to-shoot Ni translocation was slighter compared to the bulk Ni. In all three ecotypes, the walls of the root cells effectively prevented internalization of NiO NPs, providing cellular defense against Ni overload. Exposure to NiO NP led to an increase in cortex thickness and the deposition of lignin-suberin and pectin in roots, serving as a tissue-level defense mechanism against excessive Ni. Exposure to NiO NP did not modify or cause a reduction in some biomass parameters of the Ampeliko and Loutra ecotypes, while it increased all parameters in Olympos. The free salt form of Ni exerted more negative effects on biomass production than the nanoform, and the observed effects of NiO NPs can be attributed to the release of Ni ions. Nitric oxide and peroxynitrite levels were modified by NiO NPs in an ecotype-dependent manner. The changes in the abundance and activity of S-nitrosoglutathione reductase protein triggered by NiO NPs suggest that the enzyme is regulated by NiO NPs at the post-translational level. The NiO NPs slightly intensified protein tyrosine nitration, and the slight differences between the ecotypes were correlated with their biomass production in the presence of NiO NPs. Overall, the Odontarrhena lesbiaca ecotypes exhibited tolerance to NiO NPs at the cellular, tissue, organ/organism and molecular levels, demonstrating various defense mechanisms and changes in the metabolism of reactive nitrogen species metabolism and nitrosative protein modification.
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Nitro-oxidative response to internalized multi-walled carbon nanotubes in Brassica napus and Solanum lycopersicum. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 267:115633. [PMID: 37890253 DOI: 10.1016/j.ecoenv.2023.115633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 10/14/2023] [Accepted: 10/22/2023] [Indexed: 10/29/2023]
Abstract
In addition to their beneficial effects on plant physiology, multi-walled carbon nanotubes (MWCNTs) are harmful to plants in elevated concentrations. This study compared the effects of two doses of MWCNT (10 and 80 mg/L) in Brassica napus and Solanum lycopersicum seedlings focusing on nitro-oxidative processes. The presence of MWCNTs was detectable in the root and hypocotyl of both species. Additionally, transmission electron microscopy analysis revealed that MWCNTs are heavily transformed within the root cells forming large aggregates. The uptake of MWCNTs negatively affected root viability and root cell proliferation of both species, but more intense toxicity was observed in S. lycopersicum compared to B. napus. The presence of MWCNT triggered more intense protein carbonylation in the relative sensitive S. lycopersicum, where increased hydrogen peroxide levels were observed. Moreover, MWCNT exposure increased the level of physiological protein tyrosine nitration which was more intense in S. lycopersicum where notable peroxynitrite accumulation occurred. These suggest for the first time that MWCNT triggers secondary nitro-oxidative stress which contributes to its toxicity. Moreover, the results indicate that the extent of the nitro-oxidative processes is associated with the extent of MWCNT toxicity.
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Highly Porous Polymer Beads Coated with Nanometer-Thick Metal Oxide Films for Photocatalytic Oxidation of Bisphenol A. ACS APPLIED NANO MATERIALS 2023; 6:20089-20098. [PMID: 38026613 PMCID: PMC10653210 DOI: 10.1021/acsanm.3c03891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 12/01/2023]
Abstract
Highly porous metal oxide-polymer nanocomposites are attracting considerable interest due to their unique structural and functional features. A porous polymer matrix brings properties such as high porosity and permeability, while the metal oxide phase adds functionality. For the metal oxide phase to perform its function, it must be fully accessible, and this is possible only at the pore surface, but functioning surfaces require controlled engineering, which remains a challenge. Here, highly porous nanocomposite beads based on thin metal oxide nanocoatings and polymerized high internal phase emulsions (polyHIPEs) are demonstrated. By leveraging the unique properties of polyHIPEs, i.e., a three-dimensional (3D) interconnected network of macropores, and high-precision of the atomic-layer-deposition technique (ALD), we were able to homogeneously coat the entire surface of the pores in polyHIPE beads with TiO2-, ZnO-, and Al2O3-based nanocoatings. Parameters such as nanocoating thickness, growth per cycle (GPC), and metal oxide (MO) composition were systematically controlled by varying the number of deposition cycles and dosing time under specific process conditions. The combination of polyHIPE structure and ALD technique proved advantageous, as MO-nanocoatings with thicknesses between 11 ± 3 and 40 ± 9 nm for TiO2 or 31 ± 6 and 74 ± 28 nm for ZnO and Al2O3, respectively, were successfully fabricated. It has been shown that the number of ALD cycles affects both the thickness and crystallinity of the MO nanocoatings. Finally, the potential of ALD-derived TiO2-polyHIPE beads in photocatalytic oxidation of an aqueous bisphenol A (BPA) solution was demonstrated. The beads exhibited about five times higher activity than nanocomposite beads prepared by the conventional (Pickering) method. Such ALD-derived polyHIPE nanocomposites could find wide application in nanotechnology, sensor development, or catalysis.
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Facile immobilization of cholesterol oxidase on Pt,Ru-C nanocomposite and ionic liquid-modified carbon paste electrode for an efficient amperometric free cholesterol biosensing. Anal Bioanal Chem 2023; 415:5709-5722. [PMID: 37453937 DOI: 10.1007/s00216-023-04847-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023]
Abstract
In present work, the enzyme cholesterol oxidase (ChOx) was immobilized by Nafion® (Naf) on Pt,Ru-C nanocomposite and an ionic liquid (IL)-modified carbon paste electrode (CPE) in order to create cholesterol biosensor (Naf/ChOx/Pt,Ru-C/IL-CPE). The prepared working electrodes were characterized using scanning electron microscopy-energy-dispersive spectrometry, while their electrochemical performance was evaluated using electrochemical impedance spectroscopic, cyclic voltammetric, and amperometric techniques. Excellent synergism between IL 1-allyl-3-methylimidazolium dicyanamide ([AMIM][DCA]), Pt,Ru-C, and ChOx, as modifiers of CPE, offers the most pronounced analytical performance for improved cholesterol amperometric determination in phosphate buffer solution pH 7.50 at a working potential of 0.60 V. Under optimized experimental conditions, a linear relationship between oxidation current and cholesterol concentration was found for the range from 0.31 to 2.46 µM, with an estimated detection limit of 0.13 µM and relative standard deviation (RSD) below 5.5%. The optimized amperometric method in combination with the developed Naf/ChOx/Pt,Ru-C/IL-CPE biosensor showed good repeatability and high selectivity towards cholesterol biosensing. The proposed biosensor was successfully applied to determine free cholesterol in a human blood serum sample via its enzymatic reaction product hydrogen peroxide despite the presence of possible interferences. The percentage recovery ranged from 99.08 to 102.81%, while RSD was below 2.0% for the unspiked as well as the spiked human blood serum sample. The obtained results indicated excellent accuracy and precision of the method, concluding that the developed biosensor can be a promising alternative to existing commercial cholesterol tests used in medical practice.
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Hungarian and Indonesian rice husk as bioadsorbents for binary biosorption of cationic dyes from aqueous solutions: A factorial design analysis. Heliyon 2023; 9:e17154. [PMID: 37484393 PMCID: PMC10361324 DOI: 10.1016/j.heliyon.2023.e17154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 07/25/2023] Open
Abstract
The wastewater of the dye industry can be characterized by a complex chemical composition and consists of numerous dyes. Bioadsorbents are increasingly applied for the biosorption of dyes because they are inexpensive and environmentally friendly. Rice husk (RH) is a potential agricultural waste that can be converted into a bioadsorbents for the biosorption of cationic dyes. Herein, the removal of methylene blue (MB) and basic red 9 (BR9) dyes by Hungarian rice husk (HRH) and Indonesian rice husk (IRH) using binary biosorption was investigated. Adsorbents were characterized by zeta potential, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Batch biosorption evaluated the influence of different variables, including pH, adsorbent dose, contact time, and initial concentrations. Several factors that influence the biosorption of MB and BR9 onto rice husk were assessed using main effect, Pareto charts, normal probability plots, and interaction effect in a factorial design. The optimum contact time was 60 min. Isotherm and kinetic models of MB and BR9 in binary biosorption fitted to the Brunauer-Emmett-Teller multilayer and the Elovich equation based on correlation coefficients and nonlinear chi-square. Results showed that the biosorption capacity of HRH was 10.4 mg/g for MB and 10 mg/g for BR9; values for IRH were 9.3 mg/g and 9.6 mg/g, respectively. Therefore, HRH and IRH were found to be effective adsorbents for removing MB and BR9 via binary biosorption.
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Correction: Differently shaped Al2O3-based Pd catalysts loaded catalytic converter for novel non-road mobile machinery exhaust systems. REACTION KINETICS MECHANISMS AND CATALYSIS 2023. [DOI: 10.1007/s11144-023-02363-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Multi-round recycling of green waste for the production of iron nanoparticles: synthesis, characterization, and prospects in remediation. NANOSCALE RESEARCH LETTERS 2023; 18:8. [PMID: 36757485 PMCID: PMC9911567 DOI: 10.1186/s11671-023-03784-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023]
Abstract
Due to the widespread applications of metal nanoparticles (NPs), green synthesis strategies have recently advanced, e.g., methods that utilize extracts made from different plant wastes. A particularly innovative approach to reducing large amounts of available household/agricultural green wastes is their application in nanoparticle generation. Regarding this, the aim of our work was to examine the possibility of upgrading green nanoparticle syntheses from an innovative economic and environmental point of view, namely by investigating the multiple recyclabilities of green tea (GT), coffee arabica (CA), and Virginia creeper (Parthenocissus quinquefolia) (VC) waste residues for iron nanoparticle (FeNPs) synthesis. The plant extracts obtained by each extraction round were analyzed individually to determine the amount of main components anticipated to be involved in NPs synthesis. The synthesized FeNPs were characterized by X-ray powder diffraction and transmission electron microscopy. The activity of the generated FeNPs in degrading chlorinated volatile organic compounds (VOC) and thus their future applicability for remediation purposes were also assessed. We have found that VC and especially GT residues could be reutilized in multiple extraction rounds; however, only the first extract of CA was suitable for FeNPs' generation. All of the obtained FeNPs could degrade VOC with efficiencies GT1-Fe 91.0%, GT2-Fe 83.2%, GT3-Fe 68.5%; CA1-Fe 76.2%; VC1-Fe 88.2%, VC2-Fe 79.7%, respectively, where the number (as in GT3) marked the extraction round. These results indicate that the adequately selected green waste material can be reutilized in multiple rounds for nanoparticle synthesis, thus offering a clean, sustainable, straightforward alternative to chemical methods.
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B" and C subunits of PP2A regulate the levels of reactive oxygen species and superoxide dismutase activities in Arabidopsis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 195:182-192. [PMID: 36640685 DOI: 10.1016/j.plaphy.2022.12.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/14/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
The serine-threonine protein phosphatases PP2A regulate many cellular processes, however their role in oxidative stress responses and defence is less known. We show the involvement of its C (catalytic) and B" (a regulatory) subunits. The c3c4 (C subunit) and fass (B") subunit mutants and Col wt of Arabidopsis were used. Controls and treatments with the PP2A inhibitor microcystin-LR (MCY-LR) and reactive oxygen species (ROS) inducer diquat (DQ) were employed. ROS levels of primary roots were largely genotype dependent and both C and B" subunit mutants had increased sensitivity to MCY-LR and DQ indicating the involvement of these subunits in oxidative stress induction. Superoxide dismutases (SOD), mainly the Cu/Zn-SOD isoform, as key enzymes involved in ROS scavenging are also showing altered (mostly increased) activities in both c3c4 and fass mutants and have opposite relations to ROS induction. This indicates that the two types of subunits involved have partially different regulatory roles. In relation to this, control and MCY-LR/DQ treated B" subunit mutants were proven to have altered levels of phosphorylation of histone H2AX. γH2AX, the phosphorylated form indicates double stranded DNA damage during oxidative stress. Overall we point out the probable pivotal role of several PP2A subunits in the regulation of oxidative stress responses in plants and pave the way for future research to reveal the signaling pathways involved.
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Binding of Ca 2+ Ions to Alkylbenzene Sulfonates: Micelle Formation, Second Critical Concentration and Precipitation. MATERIALS 2023; 16:ma16020494. [PMID: 36676235 PMCID: PMC9864979 DOI: 10.3390/ma16020494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/20/2022] [Accepted: 12/30/2022] [Indexed: 01/06/2023]
Abstract
Anionic surfactants, such as sodium linear alkylbenzene sulfonates (NaLAS), are utilized in various fields, including industry, household, and agriculture. The efficiency of their use in aqueous environments is significantly affected by the presence of cations, Ca2+ and Mg2+ in particular, as they can decrease the concentration of the surfactant due to precipitation. To understand cation-sulfonate interactions better, we study both NaLAS colloidal solutions in the presence of CaCl2 and precipitates forming at higher salt concentrations. Upon addition of CaCl2, we find the surface tension and critical micelle concentration of NaLAS to decrease significantly, in line with earlier findings for alkylbenzylsulfonates in the presence of divalent cations. Strikingly, an increase in the surface tension is discernible above 0.6 g L-1 NaLAS, accompanied by the decrease of apparent micelle sizes, which in turn gives rise to transparent systems. Thus, there appears to be a second critical concentration indicating another micellar equilibrium. Furthermore, the maximum salt tolerance of the surfactant is 0.1 g L-1 Ca2+, above which rapid precipitation occurs yielding sparingly soluble CaLAS2∙2H2O.
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BiVO4 charge transfer control by a water-insoluble iron complex for solar water oxidation. APPLIED CATALYSIS A-GENERAL 2023. [DOI: 10.1016/j.apcata.2023.119035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Microwave-induced base-catalyzed synthesis of methyl levulinate, a further improvement in dimethyl carbonate-mediated valorization of levulinic acid. APPLIED CATALYSIS A-GENERAL 2023. [DOI: 10.1016/j.apcata.2022.119020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Concentrated Platinum‐Gallium Nanoalloy for Hydrogen Production from the Catalytic Steam Reforming of Ethanol. ChemCatChem 2022. [DOI: 10.1002/cctc.202200717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Molecular orientation rules the efficiency of immobilized antioxidants. J Colloid Interface Sci 2022; 632:260-270. [DOI: 10.1016/j.jcis.2022.11.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 11/01/2022] [Accepted: 11/11/2022] [Indexed: 11/17/2022]
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Pure Ni-Based and Trimetallic Ni-Co-Fe Catalysts for the Dry Reforming of Methane: Effect of K Promoter and the Calcination Temperature. Catal Letters 2022. [DOI: 10.1007/s10562-022-04203-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Selective production of imines and benzimidazoles by cooperative bismuth(III)/transition metal ion catalysis. J Catal 2022. [DOI: 10.1016/j.jcat.2022.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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22
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Turning CO2 to CH4 and CO over CeO2 and MCF-17 supported Pt, Ru and Rh nanoclusters – Influence of nanostructure morphology, supporting materials and operating conditions. FUEL 2022. [DOI: 10.1016/j.fuel.2022.124994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Differently shaped Al2O3-based Pd catalysts loaded catalytic converter for novel non-road mobile machinery exhaust systems. REACTION KINETICS MECHANISMS AND CATALYSIS 2022. [DOI: 10.1007/s11144-022-02291-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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A round dance of acetaldehyde molecular ensembles on Rh(111) surface; formation and decomposition of various paraldehyde conformers. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Nickel nanoparticles for liquid phase toluene oxidation – Phenomenon, opportunities and challenges. ChemCatChem 2022. [DOI: 10.1002/cctc.202200700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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CO 2 Conversion on N-Doped Carbon Catalysts via Thermo- and Electrocatalysis: Role of C–NO x Moieties. ACS Catal 2022; 12:10127-10140. [PMID: 36033366 PMCID: PMC9397536 DOI: 10.1021/acscatal.2c01589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Indexed: 11/29/2022]
Abstract
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N-doped carbon (N–C) materials are increasingly
popular
in different electrochemical and catalytic applications. Due to the
structural and stoichiometric diversity of these materials, however,
the role of different functional moieties is still controversial.
We have synthesized a set of N–C catalysts, with identical
morphologies (∼27 nm pore size). By systematically changing
the precursors, we have varied the amount and chemical nature of N-functions
on the catalyst surface. The CO2 reduction (CO2R) properties of these catalysts were tested in both electrochemical
(EC) and thermal catalytic (TC) experiments (i.e., CO2 +
H2 reaction). CO was the major CO2R product
in all cases, while CH4 appeared as a minor product. Importantly,
the CO2R activity changed with the chemical composition,
and the activity trend was similar in the EC and TC scenarios. The
activity was correlated with the amount of different N-functions,
and a correlation was found for the −NOx species. Interestingly, the amount of this species decreased
radically during EC CO2R, which was coupled with the performance
decrease. The observations were rationalized by the adsorption/desorption
properties of the samples, while theoretical insights indicated a
similarity between the EC and TC paths.
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Preparation of TiO2–MoO3 composite nanofibers by water-based electrospinning process and their application in photocatalysis. MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING 2022. [DOI: 10.1016/j.mssp.2022.106699] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Mechanochemically induced solid-state CO2 capture during the synthesis of SnO2 nanoparticles. JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 2022. [DOI: 10.1016/j.jpcs.2022.110775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Preparation and characterization of MnIn-layered double hydroxides (LDHs), extension of the synthesis to fabricate MnM(III)-LDHs (M = Al, Sc, Cr, Fe, Ga), and the comparison of their photocatalytic and catalytic activities in the oxidation of hydroquinone. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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30
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Interfacial Ni active sites strike solid solutional counterpart in CO2 hydrogenation. ENVIRONMENTAL TECHNOLOGY & INNOVATION 2022. [DOI: 10.1016/j.eti.2022.102747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Mechanochemical preparation of NiCuSn nanoparticles and composites in presence of cetyltrimethylammonium bromide (CTAB) and the catalytic application of the products in homocoupling and hydration of terminal alkynes. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Functionalized Mesoporous Silica Nanoparticles for Drug-Delivery to Multidrug-Resistant Cancer Cells. Int J Nanomedicine 2022; 17:3079-3096. [PMID: 35859731 PMCID: PMC9293248 DOI: 10.2147/ijn.s363952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/06/2022] [Indexed: 12/12/2022] Open
Abstract
Background Multidrug resistance is a common reason behind the failure of chemotherapy. Even if the therapy is effective, serious adverse effects might develop due to the low specificity and selectivity of antineoplastic agents. Mesoporous silica nanoparticles (MSNs) are promising materials for tumor-targeting and drug-delivery due to their small size, relatively inert nature, and extremely large specific surfaces that can be functionalized by therapeutic and targeting entities. We aimed to create a fluorescently labeled MSN-based drug-delivery system and investigate their internalization and drug-releasing capability in drug-sensitive MCF-7 and P-glycoprotein-overexpressing multidrug-resistant MCF-7 KCR cancer cells. Methods and Results To track the uptake and subcellular distribution of MSNs, particles with covalently coupled red fluorescent Rhodamine B (RhoB) were produced (RhoB@MSNs). Both MCF-7 and MCF-7 KCR cells accumulated a significant amount of RhoB@MSNs. The intracellular RhoB@MSN concentrations did not differ between sensitive and multidrug-resistant cells and were kept at the same level even after cessation of RhoB@MSN exposure. Although most RhoB@MSNs resided in the cytoplasm, significantly more RhoB@MSNs co-localized with lysosomes in multidrug-resistant cells compared to sensitive counterparts. To examine the drug-delivery capability of these particles, RhoB@Rho123@MSNs were established, where RhoB-functionalized nanoparticles carried green fluorescent Rhodamine 123 (Rho123) - a P-glycoprotein substrate - as cargo within mesopores. Significantly higher Rho123 fluorescence intensity was detected in RhoB@Rho123@MSN-treated multidrug-resistant cells than in free Rho123-exposed counterparts. The exceptional drug-delivery potential of MSNs was further verified using Mitomycin C (MMC)-loaded RhoB@MSNs (RhoB@MMC@MSNs). Exposures to RhoB@MMC@MSNs significantly decreased the viability not only of drug-sensitive but of multidrug-resistant cells and the elimination of MDR cells was significantly more robust than upon free MMC treatments. Conclusion The efficient delivery of Rho123 and MMC to multidrug-resistant cells via MSNs, the amplified and presumably prolonged intracellular drug concentration, and the consequently enhanced cytotoxic effects envision the enormous potential of MSNs to defeat multidrug-resistant cancer.
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Hexagonal Boron Nitride Nanosheets Protect Exfoliated Black Phosphorus Layers from Ambient Oxidation. ADVANCED MATERIALS INTERFACES 2022. [DOI: 10.1002/admi.202200857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Visible LED-light driven photocatalytic degradation of organochlorine pesticides (2,4-D & 2,4-DP) by Curcuma longa mediated bismuth vanadate. JOURNAL OF CLEANER PRODUCTION 2022. [DOI: 10.1016/j.jclepro.2022.132923] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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36
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Thermal Conductivity Enhancement of Atomic Layer Deposition Surface-Modified Carbon Nanosphere and Carbon Nanopowder Nanofluids. NANOMATERIALS 2022; 12:nano12132226. [PMID: 35808062 PMCID: PMC9267995 DOI: 10.3390/nano12132226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 12/03/2022]
Abstract
In this paper, we present a study on thermal conductivity and viscosity of nanofluids containing novel atomic layer deposition surface-modified carbon nanosphere (ALD-CNS) and carbon nanopowder (ALD-CNP) core-shell nanocomposites. The nanocomposites were produced by atomic layer deposition of amorphous TiO2. The nanostructures were characterised by scanning (SEM) and transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, thermogravimetry/differential thermal analysis (TG/DTA) and X-ray powder diffraction (XRD). High-concentration, stable nanofluids were prepared with 1.5, 1.0 and 0.5 vol% nanoparticle content. The thermal conductivity and viscosity of the nanofluids were measured, and their stability was evaluated with Zeta potential measurements. The ALD-CNS enhanced the thermal conductivity of the 1:5 ethanol:water mixture by 4.6% with a 1.5 vol% concentration, and the viscosity increased by 37.5%. The ALD-CNS increased the thermal conductivity of ethylene–glycol by 10.8, whereas the viscosity increased by 15.9%. The use of a surfactant was unnecessary due to the ALD-deposited TiO2 layer.
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Interfacial charge separation of nickel phosphide anchored on anatase-hematite heterojunction for stimulating visible light driven hydrogen generation. INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2022. [DOI: 10.1016/j.ijhydene.2022.05.148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Epigallocatechine-3-gallate Inhibits the Adipogenesis of Human Mesenchymal Stem Cells via the Regulation of Protein Phosphatase-2A and Myosin Phosphatase. Cells 2022; 11:cells11101704. [PMID: 35626740 PMCID: PMC9140100 DOI: 10.3390/cells11101704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 02/01/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) has widespread effects on adipocyte development. However, the molecular mechanisms of EGCG are not fully understood. We investigate the adipogenic differentiation of human-derived mesenchymal stem cells, including lipid deposition and changes in the expression and phosphorylation of key transcription factors, myosin, protein phosphatase-2A (PP2A), and myosin phosphatase (MP). On day 6 of adipogenic differentiation, EGCG (1–20 µM) suppressed lipid droplet formation, which was counteracted by an EGCG-binding peptide for the 67 kDa laminin receptor (67LR), suggesting that EGCG acts via 67LR. EGCG decreased the phosphorylation of CCAAT-enhancer-binding protein beta via the activation of PP2A in a protein kinase A (PKA)-dependent manner, leading to the partial suppression of peroxisome proliferator-activated receptor gamma (PPARγ) and adiponectin expression. Differentiated cells exhibited a rounded shape, cortical actin filaments, and lipid accumulation. The EGCG treatment induced cell elongation, stress fiber formation, and less lipid accumulation. These effects were accompanied by the degradation of the MP target subunit-1 and increased the phosphorylation of the 20 kDa myosin light chain. Our results suggest that EGCG acts as an agonist of 67LR to inhibit adipogenesis via the activation of PP2A and suppression of MP. These events are coupled with the decreased phosphorylation and expression levels of adipogenic transcription factors and changes in cell shape, culminating in curtailed adipogenesis.
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Investigation of the adsorption properties of cyclic C6 molecules on h-BN/Rh(111) surface, efforts to cover the boron nitride nanomesh by graphene. SURFACES AND INTERFACES 2022. [DOI: 10.1016/j.surfin.2022.102034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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40
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EDTA analogues – unconventional inhibitors of gypsum precipitation. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Rapid direct cathodic voltammetric determination of insecticide flonicamid by renewable silver-amalgam film electrode. INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY 2022. [DOI: 10.1080/03067319.2022.2054706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Effect of Excess B in Ni 2P-Coated Boron Nitride on the Photocatalytic Hydrogen Evolution from Water Splitting. ACS APPLIED ENERGY MATERIALS 2022. [DOI: 10.1021/acsaem.1c04086] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Morphological aspects determine the catalytic activity of porous hydrocalumites: the role of the sacrificial templates. MATERIALS TODAY CHEMISTRY 2022. [DOI: 10.1016/j.mtchem.2021.100682] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Optimization of layering technique and secondary structure analysis during the formulation of nanoparticles containing lysozyme by quality by design approach. PLoS One 2021; 16:e0260603. [PMID: 34882727 PMCID: PMC8659335 DOI: 10.1371/journal.pone.0260603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 11/13/2021] [Indexed: 12/03/2022] Open
Abstract
In our study, core-shell nanoparticles containing lysozyme were formulated with precipitation and layering self-assembly. Factorial design (DoE) was applied by setting the process parameters during the preparation with Quality by Design (QbD) approach. The factors were the concentration of lysozyme and sodium alginate, and pH. Our aim was to understand the effect of process parameters through the determination of mathematical equations, based on which the optimization parameters can be predicted under different process parameters. The optimization parameters were encapsulation efficiency, particle size, enzyme activity and the amount of α-helix structure. The nanoparticles were analysed with transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD) spectroscopy. Based on our results, we found that pH was the most important factor and pH 10 was recommended during the formulation. Enzyme activity and α-helix content correlated with each other very well, and particle size and encapsulation efficiency also showed very good correlation with each other. The results of the α-helix content of FTIR and CD measurements were very similar for the precipitated lysozyme due to the solid state of lysozyme. The mixing time had the best influence on the encapsulation efficiency and the particle size, which leads to the conclusion that a mixing time of 1 h is recommended. The novelty in our study is the presentation of a mathematical model with which the secondary structure of the protein and other optimization parameters can be controlled in the future during development of nanoparticle based on the process parameters.
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Abstract
Abstract
In this study, we evaluate the variation of the work function of phosphorene during thermal oxidation at different temperatures. The ultraviolet photoelectron spectroscopy results show an N-shaped behaviour that is explained by the oxidation process and the dangling-to-interstitial conversion at elevated temperatures. The exfoliation degree and x-ray photoelectron spectroscopy confirm the formation of native oxides in the top-most layer that passivates the material. Ex-situ XPS reveals the full oxidation of monolayers at temperatures higher than 140 °C, but few-layer phosphorene withstands the thermal oxidation even up to 200 °C with slight modifications of the A
2
g/A
1
g and A
2
g/B
2g vibrational mode ratios and a weak fluorescence in the Raman spectra of the heat-treated samples.
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Copper-Loaded Layered Bismuth Subcarbonate-Efficient Multifunctional Heterogeneous Catalyst for Concerted C-S/C-N Heterocyclization. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42650-42661. [PMID: 34477369 PMCID: PMC8447192 DOI: 10.1021/acsami.1c09234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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An efficient self-supported
Cu(II)Bi(III) bimetallic catalyst with
a layered structure was designed and developed. By careful characterization
of the as-prepared material, the host structure was identified to
exhibit a Sillen-type bismutite framework, with copper(II) ions being
loaded as guests. The heterogeneous catalyst enabled C–N and
C–S arylations under mild reaction conditions and with high
chemoselectivities, thus furnishing valuable phenothiazines via heterocyclization with wide substrate tolerance. As
corroborated by detailed catalytic studies, the cooperative, bifunctional
catalyst, bearing Lewis acid sites along with copper(II) catalytic
sites, facilitated an intriguing concerted C–N/C–S heterocyclization
mechanism. The heterogeneous nature of the catalytic reactions was
verified experimentally. Importantly, the catalyst was successfully
recycled and reused multiple times, persevering its original structural
order as well as its initial activity.
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M(II)Al 4 Type Layered Double Hydroxides-Preparation Using Mechanochemical Route, Structural Characterization and Catalytic Application. MATERIALS 2021; 14:ma14174880. [PMID: 34500969 PMCID: PMC8432663 DOI: 10.3390/ma14174880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/02/2022]
Abstract
The synthesis of the copper-poor and aluminum-rich layered double hydroxides (LDHs) of the CuAl4 type was optimized in detail in this work, by applying an intense mechanochemical treatment to activate the gibbsite starting reagent. The phase-pure forms of these LDHs were prepared for the first time; using copper nitrate and perchlorate salts during the syntheses turned out to be the key to avoiding the formation of copper hydroxide sideproducts. Based on the use of the optimized syntheses parameters, the preparation of layered triple and multiple hydroxides was also attempted using Ni(II), Co(II), Zn(II) and even Mg(II) ions. These studies let us identify the relative positions of the incorporating cations in the well-known selectivity series as Ni2+ >> Cu2+ >> Zn2+ > Co2+ >> Mg2+. The solids formed were characterized by using powder X-ray diffractometry, UV–Vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. The catalytic potential of the samples was investigated in carbon monoxide oxidation reactions at atmospheric pressure, supported by an in situ diffuse reflectance infrared spectroscopy probe. All solids proved to be active and the combination of the nickel and cobalt incorporation (which resulted in a NiCoAl8 layered triple hydroxide) brought outstanding benefits regarding low-temperature oxidation and increased carbon monoxide conversion values.
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Polyvinyl-Pyrrolidone-Coated Silver Nanoparticles-The Colloidal, Chemical, and Biological Consequences of Steric Stabilization under Biorelevant Conditions. Int J Mol Sci 2021; 22:8673. [PMID: 34445378 PMCID: PMC8395525 DOI: 10.3390/ijms22168673] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022] Open
Abstract
(1) Background: Several properties of silver nanoparticles (AgNPs), such as cytotoxic, anticancer, and antimicrobial activities, have been subjects of intense research; however, important aspects such as nanoparticle aggregation are generally neglected, although a decline in colloidal stability leads to a loss of the desired biological activities. Colloidal stability is affected by pH, ionic strength, or a plethora of biomolecules that interact with AgNPs under biorelevant conditions. (2) Methods: As only a few studies have focused on the relationship between aggregation behavior and the biological properties of AgNPs, here, we have systematically evaluated this issue by completing a thorough analysis of sterically (via polyvinyl-pyrrolidone (PVP)) stabilized AgNPs that were subjected to different circumstances. We assessed ultraviolet-visible light absorption, dynamic light scattering, zeta potential measurements, in vitro cell viability, and microdilution assays to screen both colloidal stability as well as bioactivity. (3) Results: The results revealed that although PVP provided outstanding biorelevant colloidal stability, the chemical stability of AgNPs could not be maintained completely with this capping material. (4) Conclusion: These unexpected findings led to the realization that stabilizing materials have more profound importance in association with biorelevant applications of nanomaterials than just being simple colloidal stabilizers.
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Role of active metals Cu, Co, and Ni on ceria towards CO2 thermo-catalytic hydrogenation. REACTION KINETICS MECHANISMS AND CATALYSIS 2021. [DOI: 10.1007/s11144-021-02007-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Microcystin-LR, a cyanobacterial toxin affects root development by changing levels of PIN proteins and auxin response in Arabidopsis roots. CHEMOSPHERE 2021; 276:130183. [PMID: 34088085 DOI: 10.1016/j.chemosphere.2021.130183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
Microcystin-LR (MCY-LR) is a heptapeptide toxin produced mainly by freshwater cyanobacteria. It strongly inhibits protein phosphatases PP2A and PP1. Functioning of the PIN family of auxin efflux carriers is crucial for plant ontogenesis and their functions depend on their reversible phosphorylation. We aimed to reveal the adverse effects of MCY-LR on PIN and auxin distribution in Arabidopsis roots and its consequences for root development. Relatively short-term (24 h) MCY-LR treatments decreased the levels of PIN1, PIN2 and PIN7, but not of PIN3 in tips of primary roots. In contrast, levels of PIN1 and PIN2 increased in emergent lateral roots and their levels depended on the type of PIN in lateral root primordia. DR5:GFP reporter activity showed that the cyanotoxin-induced decrease of auxin levels/responses in tips of main roots in parallel to PIN levels. Those alterations did not affect gravitropic response of roots. However, MCY-LR complemented the altered gravitropic response of crk5-1 mutants, defective in a protein kinase with essential role in the correct membrane localization of PIN2. For MCY-LR treated Col-0 plants, the number of lateral root primordia but not of emergent laterals increased and lateral root primordia showed early development. In conclusion, inhibition of protein phosphatase activities changed PIN and auxin levels, thus altered root development. Previous data on aquatic plants naturally co-occurring with the cyanotoxin showed similar alterations of root development. Thus, our results on the model plant Arabidopsis give a mechanistic explanation of MCY-LR phytotoxicity in aquatic ecosystems.
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