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International Journal of Biological... Jul 2023In this study, the modified citrus peel pectins (CPPs) were successfully produced by electrochemistry with varying NaCl concentrations of 0, 0.01 % and 0.1 % w/v...
In this study, the modified citrus peel pectins (CPPs) were successfully produced by electrochemistry with varying NaCl concentrations of 0, 0.01 % and 0.1 % w/v using an H-type cell at 40 mA current. After 4 h, the pH and oxidation-reduction potential (ORP) of oxidized CPP solution in the anodic region were 2.00- 2.52 and 371.17- 564.45 mV, respectively, due to the electrolysis of water, whereas those of reduced CPP solution in cathodic region were 9.46- 10.84 and - 202.77 ∼ -230.57 mV. The modified CPPs in the anodic region (A-0, A-0.01, and A-0.1) exhibited significantly higher weight-average molecular weights and methyl esterification degrees than those in the cathodic region (C-0, C-0.01 and C-0.1). In contrast, the K, Mg, and Ca contents of A-0, A-0.01, and A-0.1 were lower than those of C-0, C-0.01 and C-0.1 due to the electrophoretic migration. Furthermore, the antioxidant activities of A-0 and A-0.01 solutions were stronger than those of the C-0, C-0.01, and C-0.1, while rheological and texture properties of their hydrogels showed contradictory results. Finally, the potential structure-function relationships of CPPs were explored by combining PCA and correlation analysis. Overall, this study introduced a potential approach for pectin purification and functional low-methoxyl pectin manufacturing.
Topics: Citrus; Sodium Chloride; Electrochemistry; Pectins; Structure-Activity Relationship
PubMed: 37268072
DOI: 10.1016/j.ijbiomac.2023.125147 -
RSC Advances Dec 2023Gas sensors are used to detect gas components in human breath to diagnose diseases, such as cancers. However, choosing suitable two-dimensional materials for gas sensors...
Gas sensors are used to detect gas components in human breath to diagnose diseases, such as cancers. However, choosing suitable two-dimensional materials for gas sensors is a challenge. Germanene can be a good candidate because of its outstanding electronic and structural properties. Based on the density functional theory calculations with various schemes, such as PBE + vdW-DF2, HSE06 + PBE, and HSE06 + vdW-DF2, we elucidated the structural and electronic properties of germanene substrates (perfect, vacancy-1, and vacancy-2) while adsorbing hepatocellular carcinoma-related volatile organic compounds (VOCs), , acetone, 1,4-pentadiene, methylene chloride, phenol, and allyl methyl sulfide. These gases have been selected for investigation because of their most frequent occurence in diagnosing the disease. We found that vacancy substrates enhanced the adsorption strength of the VOCs compared to the perfect one, where the phenol adsorbed most strongly and exhibited the most profound influence on the structural deformation of the substrates over the other VOCs. Besides, the adsorbed VOCs significantly modified the energy bandgap of the considered germanene substrates. In particular, the gases, except allyl methyl sulfide, vanished the bandgap of the vacancy-1 germanene and converted this substrate from a semiconductor to a metal, while they widened the bandgap of the vacancy-2 structure compared to the isolated case. Therefore, the perfect and vacancy-2 germanene sheets could maintain their semiconducting state upon gas adsorption, implying that these substrates may be suitable candidates for gas sensing applications. The nature of the interaction between the VOCs and the germanene substrates is a physical adsorption with a weak charge exchange, which mainly comes from the contribution of the p orbital of the VOCs and the p orbital of Ge.
PubMed: 38090092
DOI: 10.1039/d3ra05927h -
Dalton Transactions (Cambridge, England... Oct 2023The iridium(I)-aminophosphane complex [Ir{κ,,'-(SiNP-H)}(cod)] has been prepared by reaction of [IrCl(cod)(SiNP)] with KCHCOO. DFT calculations show that this reaction...
The iridium(I)-aminophosphane complex [Ir{κ,,'-(SiNP-H)}(cod)] has been prepared by reaction of [IrCl(cod)(SiNP)] with KCHCOO. DFT calculations show that this reaction takes place through an unexpected outer sphere mechanism (SiNP = SiMe{N(4-CHMe)PPh}; SiNP-H = CHSiMe{N(4-CHMe)PPh}). The reaction of [IrCl(cod)(SiNP)] or [Ir{κ,,'-(SiNP-H)}(cod)] with diverse oxidants has been explored, yielding a range of iridium(III) derivatives. On one hand, [IrCl(cod)(SiNP)] reacts with allyl chloride rendering the octahedral iridium(III) derivative [IrCl(η-CH)(SiNP)], which, in turn, reacts with -butyl isocyanide yielding the substitution product [IrCl(η-CH)(CNBu)(SiNP)]Cl the observed intermediate [IrCl(η-CH)(CNBu)(SiNP)]. On the other hand, the reaction of [Ir{κ,,'-(SiNP-H)}(cod)] with [FeCp]X (X = PF, CFSO), I or CFSOCH results in the metal-centered two-electron oxidation rendering a varied assortment of iridium(III) compounds. [Ir{κ,,'-(SiNP-H)}(cod)] reacts with [FeCp] (1 : 2) in acetonitrile affording [Ir{κ,,'-(SiNP-H)}(CHCN)] isolated as both the triflato and the hexafluorophosphato derivatives. Also, the reaction of [Ir{κ,,'-(SiNP-H)}(cod)] with I (1 : 1) yields a mixture of iridium(III) derivatives, namely the mononuclear compound [IrI(κ,'-SiNP)(η,η-CH)]I, containing the η,η-cycloocta-2,6-dien-1-yl ligand, and two isomers of the dinuclear derivative [Ir{κ,,'-(SiNP-H)}(μ-I)]I, the first species being isolated in low yield. DFT calculations indicate that [IrI(κ,'-SiNP)(η,η-CH)]I forms as the result of a bielectronic oxidation of iridium(I) followed by the deprotonation of the cod ligand by iodide and the protonation of the methylene moiety of the [Ir{κ,,'-(SiNP-H)}] platform by the newly formed HI. Finally, the oxidation of [Ir{κ,,'-(SiNP-H)}(cod)] by methyl triflate proceeds a hydride abstraction from the cod ligand, with the elimination of methane and the formation of the η,η-cycloocta-2,6-dien-1-yl ligand with the concomitant two-electron oxidation of the iridium centre. The crystal structures of selected compounds have been determined.
PubMed: 37706349
DOI: 10.1039/d3dt02361c -
Chemical Society Reviews Jul 2023Diversification of polymer waste recycling is one of the solutions to improve the current environmental scenario. Upcycling is a promising strategy for converting... (Review)
Review
Diversification of polymer waste recycling is one of the solutions to improve the current environmental scenario. Upcycling is a promising strategy for converting polymer waste into molecular intermediates and high-value products. Although the catalytic transformations into small molecules have been actively discussed, the methods and characteristics of upcycling into new materials have not yet been addressed. Recently, the functionalisation of polymer wastes (polyethylene terephthalate bottles, polypropylene surgical masks, rubber tires, ) and their conversion into new materials with enhanced functionality have been proposed as an appealing alternative for dealing with polymer waste recycling/treatment. In this review, the term 'functional upcycling' is introduced to designate any method of post-polymerisation modification or surface functionalisation without considerable polymer chain destruction to produce a new upcycled material with added value. This review explores the functional upcycling strategy with detailed consideration of the most common polymers, , polystyrene, poly(methyl methacrylate), polyethylene, polypropylene, polyurethane, polyethylene terephthalate, polyvinyl chloride, polycarbonate, and rubber. We discuss the composition of plastic waste, reactivity, available physical/chemical agents for modification, and the interconnection between their properties and application. To date, upcycled materials have been successfully applied as adsorbents (including CO), catalysts, electrode materials for energy storage and sensing, demonstrating a high added value. Importantly, the reviewed reports indicated that the specific performance of upcycled materials is generally comparable or higher than that of similar materials prepared from virgin polymer feedstock. All these advantages promote functional upcycling as a promising diversification approach against the common postprocessing methods employed for polymer waste. Finally, to identify the limitations and suggest future scope of research for each polymer, we comparatively analysed the aspects of functional upcycling with those of chemical and mechanical recycling, considering the energy and resource costs, toxicity of the used chemicals, environmental footprint, and the value added to the product.
PubMed: 37403690
DOI: 10.1039/d2cs00689h -
ACS Omega Oct 2023Eutectic solvent systems are versatile solvents that have found widespread use in numerous applications. Traditional solvents are homogeneous, having only one component,...
Eutectic solvent systems are versatile solvents that have found widespread use in numerous applications. Traditional solvents are homogeneous, having only one component, and their chemistry is relatively simple, with some exceptions. On the other hand, deep eutectic solvents (DESs) comprise binary components, generally a donor and an acceptor in hydrogen bonding with varying ratios. The interaction chemistry among the donor and acceptor involved in hydrogen bonding in DESs is complicated. Although numerous research is focused on the synthesis and application of DESs, few studies are reported to elucidate the complex structure and dynamic and interaction behavior of DESs. In this study, we employed calorimetry, vibrational spectroscopy techniques including FTIR and Raman, and nuclear magnetic resonance to derive insight into the structural feature and noncovalent contact of choline chloride (ChCl) and citric acid (CA) while they formed DESs. The 1:1 ChCl/CA eutectic system showed phase transitions and melting peaks with the most pronounced peak at 156.22 °C, suggesting the DESs melting at a lower temperature than the melting temperatures of ChCl and CA. In addition to IR and Raman findings, H NMR investigations demonstrate hydrogen bonding intermolecular interactions between ChCl and CA, supporting the formation of 1:1 ChCl/CA DESs based on the deshielded chemical shifts of the proton for Ch. The interaction of the chloride anion with the methyl protons (H4) and methylene protons (H3) of ChCl as well as the strong hydrogen bonding interactions between the hydroxyl hydrogen (H1) of ChCl with one of CA's carbonyl oxygens both supported the formation of conformer E. In addition, molecular dynamics followed by the density functional theory (DFT) was employed to visualize the structure and interaction of DESs using the ωB97XD theory and 6-311++G (d,p) basis set. Both experimental and theoretical IR, Raman, and structural analyses provided evidence of the formation of DESs by possessing hydrogen bonds. These multifaceted experimental and computational investigations provide details of structural and intermolecular interactions of ChCl/CA DESs.
PubMed: 37867676
DOI: 10.1021/acsomega.3c04570 -
ACS Omega Aug 2023Sixteen chemically varied metabolites were isolated from the bulbs of (L'Her.) Herb., including eight flavonoids [3'-methyl isoliquiritigenin , 7-hydroxyflavan ,...
Sixteen chemically varied metabolites were isolated from the bulbs of (L'Her.) Herb., including eight flavonoids [3'-methyl isoliquiritigenin , 7-hydroxyflavan , 7-hydroxyflavanone , 7-hydroxyflavan-3-ol , 7-methoxy-3',4'-methylenedioxyflavan-3-ol , 7-hydroxy-3',4'-methylenedioxy flavan , 2',4'-dihydroxy-3'-methyl-3,4-methylenedioxychalcone , and isoliquiritigenin ], four acetophenones [2,6-dimethoxy-4-hydroxyacetophenone , 2,4-dihydroxyacetophenone , 2,4-dihydroxy-6-methoxy-3-methylacetophenone , and 2,4,6-trimethoxyacetophenone ], two alkaloids [lycorine and narciprimine ], one phenol derivative [-nitrophenol ], and one steroid [β-sitosterol 3--β-glucopyranoside ]. Their structures were elucidated by combining one- and two-dimensional NMR and ESI-MS techniques and by comparison with the reported literature data and some authentic samples. Except for lycorine , the isolated metabolites were obtained herein for the first time from plants, among which compound was identified as a new chalcone derivative. Additionally, the total phenolic and flavonoid contents of the total ethanol extract and different fractions of the bulbs were determined by the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively, whereas their antioxidant potential was compared using the phosphomolybdenum and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. Finally, the binding affinities of compounds to some key target proteins of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), namely, main protease (M), papain-like protease (PLpro), and RNA-dependent RNA polymerase (RdRp), were screened and compared using molecular docking analysis. The possible chemotaxonomic significance of the identified metabolites was also discussed.
PubMed: 37546665
DOI: 10.1021/acsomega.2c07886 -
Molecules (Basel, Switzerland) Dec 2023Lily is one of the most important cut flowers in the world, with a rich floral fragrance. To further explore the fragrance emission mechanisms of lily cultivars,...
Lily is one of the most important cut flowers in the world, with a rich floral fragrance. To further explore the fragrance emission mechanisms of lily cultivars, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and organic solvent extraction-gas chromatography-mass spectrometry (OSE-GC-MS) were used to unveil the volatile organic compounds (VOCs) and endogenous extracts of seven lily cultivars. Furthermore, real-time quantitative PCR (qRT-PCR) was used to determine the expression levels of two key genes ( and ) related to the biosynthesis of monoterpenoids and methyl benzoate. The results show that forty-five VOCs were detected in the petals of seven lily cultivars, and the main compounds were monoterpenoids and phenylpropanoids/benzenoids. Dichloromethane was the best solvent for extracting the endogenous extracts of 'Viviana' petals and eighteen endogenous extracts were detected using dichloromethane to extract the petals of seven lily cultivars. Each compound's emission ratio (natural logarithm of the ratio of VOC content to endogenous extract content) was calculated, and linear regression analyses between emission ratios and boiling points were conducted. Significant linear negative correlations existed between the emission ratios and boiling points of compounds, and the regression equations' coefficients of determination () were all greater than 0.7. was expressed highly in 'Viviana', 'Pink News', and 'Palazzo', and was expressed highly in 'Pink News' and 'Palazzo'. Correlation analyses between the gene expression levels and the monoterpenoids and methyl benzoate contents found that the expression levels have strong positive correlations with monoterpenoids content, while no correlations were found between the expression levels of and the contents of methyl benzoate. This study lays the foundation for research on the release patterns of VOCs in the flowers of , and the breeding of lilies for their floral fragrance.
Topics: Lilium; Volatile Organic Compounds; Methylene Chloride; Plant Breeding; Flowers; Solid Phase Microextraction; Solvents; Monoterpenes
PubMed: 38138428
DOI: 10.3390/molecules28247938 -
Polymers Nov 2023Ion bombardment is an important tool of materials processing, but usually leads to erosion of the surface and significant thickness reductions when thin layers are used....
Ion bombardment is an important tool of materials processing, but usually leads to erosion of the surface and significant thickness reductions when thin layers are used. The growing use of polymer thin films in a variety of applications, from coatings and membranes to biomedical and electronic devices, calls for a deeper understanding of the thinning process induced by energetic ions espe-cially for very thin films. Here, thinning and surface morphology changes induced by high-energy ion bombardment in PMMA and PVC thin films were investigated, focusing on the role of the initial thickness of the films and the stopping power of the ions. We used thin films with initial thicknesses varying from 13 to 800 nm, and light and heavy ions as projectiles in the energy range of 2-2000 MeV, where the electronic stopping dominates. Thickness reductions as a function of fluence were monitored and thinning cross sections were extracted from curves. A supralinear scaling between the thinning cross sections and the electronic stopping power of the beams was observed, with a much enhanced thinning efficiency for the swift heavy ions. The scaling with the stopping power dE/dx is almost independent of the initial thickness of the films. At intermediate and large fluences, changes in the physicochemical properties of the irradiated polymers may modulate and decelerate the thinning process of the remaining film. The importance of this secondary process depends on the stopping power and the balance between erosion and the chemical transformations induced by the beam. We also observe a trend for the thinning efficiency to become larger in very thin films. Depending on the type of beam and polymer, this effect is more or less pronounced. PMMA films irradiated with 2 MeV H show the most systematic correlation between initial thickness and thinning cross sections, while in PVC films the initial thickness plays a minor role for all investigated beams.
PubMed: 38231893
DOI: 10.3390/polym15234471 -
Angewandte Chemie (International Ed. in... Nov 2023A copper-catalyzed dearomative alkynylation of pyridines is reported with excellent regio- and enantioselectivities. The synthetically valuable enantioenriched...
A copper-catalyzed dearomative alkynylation of pyridines is reported with excellent regio- and enantioselectivities. The synthetically valuable enantioenriched 2-alkynyl-1,2-dihydropyridine products afforded are generated from the readily available feedstock, pyridine, and commercially available terminal alkynes. The three-component reaction between a pyridine, a terminal alkyne, and methyl chloroformate employs copper chloride and StackPhos, a chiral biaryl P,N- ligand, as the catalytic system. Under mild reaction conditions, the desired 1,2-addition products are delivered in up to 99 % yield with regioselectivity ratios up to 25 : 1 and enantioselectivities values of up to 99 % ee. Activated and non-activated terminal alkynes containing a wide range of functional groups are well tolerated. Even acetylene gas delivered mono-alkynylated products in high yield and ee. Application of the methodology in an efficient enantioselective synthesis of the chiral piperidine indolizidine, coniceine, is reported.
PubMed: 37820350
DOI: 10.1002/anie.202312967 -
Polymers Sep 2023Excellent mechanical properties and self-healing properties are very important for the practical application of hydrogel flexible sensors. In this study, acrylic acid...
Excellent mechanical properties and self-healing properties are very important for the practical application of hydrogel flexible sensors. In this study, acrylic acid and stearyl methyl acrylate were selected as monomers to synthesize hydrophobic association hydrogels, and multi-physically cross-linked hydrogels were synthesized by adding ferric chloride and polyvinyl alcohol to introduce ion interaction and a hydrogen bond cross-linking network. The hydrogels were characterized by FTIR, XRD and SEM, and the mechanical properties and self-healing properties were tested using a universal testing machine. It was confirmed that the strength of the hydrogel was significantly improved with the addition of ferric chloride and polyvinyl alcohol, and the hydrogel still showed good self-healing properties. Further testing of its application as a conductive sensor has demonstrated sensitive and stable motion sensing capabilities. This provides an important reference for high-performance hydrogel sensors with both high strength and self-healing properties.
PubMed: 37765600
DOI: 10.3390/polym15183748