jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Mostafa M. El‐Sheekh | Mohamed Deyab | Nagwa I. Hassan | Seham E. Abu Ahmed
Source: RENDICONTI LINCEI (article, 2022-10-28)
Field: Materials Science — Materials Chemistry

Green biosynthesis of silver nanoparticles using sodium alginate extracted from Sargassum latifolium and their antibacterial activity Abstract Brown seaweed Sargassum latifolium produces a sufficient amount of alginate. It is derived from the cell wall of seaweed as a natural anionic polysaccharide. In the present study, alginate was extracted from S. latifolium , its physicochemical properties, the potential for silver nanoparticles formation, characterization of alginate silver nanoparticles, and its antibacterial activity was studied. Physical analysis of extracted sodium alginate as colour (pale yellow), yield (25.34%), water content (13.17%), ash content (15.5%), and pH (8.6) were investigated. In addition, UV scan analyses of extracted alginate illustrated that the bioactive compounds separated in the range of 200–400 nm. On the other hand, ultraviolet–visible spectroscopy (UV–Vis) scan analysis of synthesized alginate silver nanoparticles gave a maximum peak at 413 nm. Besides that, Fourier Transforms Infrared spectroscopy (FT-IR) analysis of alginate, and alginate silver nanoparticles revealed a variety of functional groups, such as –OH, –NH, –CH, –COOH, CO, and C–C, and thermogravimetric analysis of extracted sodium alginate demonstrated thermal degradation occurs in two steps; Dehydration followed by degradation to Na 2 CO 3 and a carbonized substance that breaks down slowly between 600 and 750 °C in N 2 . Biochemical contents, protein, and carbohydrate were receptively, respectively, and were 0.89 and 78.56 mg/g dry wt. Alginate silver nanoparticles recorded maximal antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli, Bacillus subtilis, and Bacillus cereus more than alginate. On the other hand, alginate has no activity against E. coli . Nuclear chemistry ; Antibacterial activity ; Thermogravimetric analysis ; Silver nanoparticle ; Chemistry ; Bacillus cereus ; Bacillus subtilis ; Polysaccharide ; Nanoparticle ; Sargassum ; Chitosan ; Fourier transform infrared spectroscopy ; Bacteria ; Organic chemistry ; Materials science ; Botany ; Chemical engineering ; Nanotechnology ; Biology ; Algae Nanoparticles: synthesis and applications ; Bone Tissue Engineering Materials ; Graphene and Nanomaterials Applications
Authors: Tushar Dhanani | Tianyi Dou | Kishan Biradar | John L. Jifon | Dmitry Kurouski | Bhimanagouda S. Patil
Source: Frontiers in Plant Science (article, 2022-05-31)
Field: Chemistry — Analytical Chemistry

Raman Spectroscopy Detects Changes in Carotenoids on the Surface of Watermelon Fruits During Maturation A non-invasive and non-destructive technique, Raman spectroscopy, was explored to distinguish different maturity stages (20, 30, 40, and 50 days after anthesis) of watermelon (<i>Citrullus lanatus</i>) fruits from four cultivars: Fascination, Orange Crisp, Amarillo and Crimson Sweet. Spectral acquisition from the fruit surface was carried out at the wavelength range of 400-2,000 cm<sup>-1</sup> using a handheld Raman spectrometer equipped with 830 nm laser excitation source. The spectra were normalized at 1,438 cm<sup>-1</sup> which was assigned to CH<sub>2</sub> and CH<sub>3</sub> vibration. Detecting changes in the spectral features of carotenoids on the surface of watermelon fruits can be used as a marker to monitor the maturity of the fruit. The spectral analysis confirmed the presence of two major carotenoids, lutein and β-carotene, and their intensity decreased upon maturity on the fruit surface. Identification of these pigments was further confirmed by resonance Raman spectra and high-performance liquid chromatography analysis. Results of partial least square discriminant analysis of pre-processed spectra have demonstrated that the method can successfully predict the maturity of watermelon samples with more than 85% accuracy. Analysis of Variance of individual Raman bands has revealed a significant difference among the stages as the level of carotenoids was declined during the ripening of the fruits. Thus, Raman spectral signatures can be used as a versatile tool for the non-invasive determination of carotenoid changes on the watermelon fruits' surface during ripening, thereby enabling effective monitoring of nutritional quality and maturity indices before harvesting the watermelon. Citrullus lanatus ; Ripening ; Carotenoid ; Lycopene ; Raman spectroscopy ; Horticulture ; Orange (colour) ; Chemistry ; Ripeness ; Botany ; Analytical Chemistry (journal) ; Food science ; Biology ; Chromatography ; Optics ; Physics Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Identification and Quantification in Food
Authors: Guifu Si | Chen Tan | Min Chen | Changle Chen
Source: Angewandte Chemie International Edition (article, 2022-05-05)
Field: Chemistry — Organic Chemistry

A Cocatalyst Strategy to Enhance Ruthenium‐Mediated Metathesis Reactivity towards Electron‐Deficient Substrates Ruthenium-mediated olefin metathesis has been widely applied for the synthesis of various organic molecules and polymers. Inspired by the cocatalyst strategy for olefin polymerization, here we demonstrate that the abstraction of a chloride ion from various commercially available ruthenium catalysts significantly enhances their reactivity towards electron-deficient internal olefins. This cocatalyst strategy can be implemented in ethenolysis and cross-metathesis reactions of FG-CH=CH-FG type substrates bearing electron-withdrawing groups and the synthesis of telechelic polymers that can be converted to polyethylene-like materials with closed-loop recycling properties. The copolymerization of cyclic substrate with cycloolefins followed by hydrogenation afforded polyolefin materials with in-chain break points. Interestingly, switchable catalysis was achieved in the absence and presence of a cocatalyst, which allowed the polymer microstructure and material properties to be fine-tuned. Polyolefin ; Ruthenium ; Acyclic diene metathesis ; Reactivity (psychology) ; Polymer ; Metathesis ; Catalysis ; Ring-opening metathesis polymerisation ; Copolymer ; Polyethylene ; Polymerization ; Olefin fiber ; Polymer chemistry ; Materials science ; Organic chemistry ; Chemistry Synthetic Organic Chemistry Methods ; Organometallic Complex Synthesis and Catalysis ; biodegradable polymer synthesis and properties
Authors: Irene Tagliaro | Stefano Seccia | Beatrice Pellegrini | Sabrina Bertini | Carlo Antonini
Source: Carbohydrate Polymers (article, 2022-11-29)
Field: Materials Science — Surfaces, Coatings and Films

Chitosan-based coatings with tunable transparency and superhydrophobicity: A solvent-free and fluorine-free approach by stearoyl derivatization Chitosan ; Coating ; Materials science ; Derivatization ; Superhydrophobic coating ; Chemical engineering ; Solvent ; Nanotechnology ; Organic chemistry ; Chemistry Surface Modification and Superhydrophobicity ; Advanced Sensor and Energy Harvesting Materials ; Electrospun Nanofibers in Biomedical Applications
Authors: Jakub Kupecki | Anna Niemczyk | Stanisław Jagielski | Ryszard Kluczowski | Magdalena Kosiorek | Krystian Machaj
Source: International Journal of Hydrogen Energy (article, 2022-05-04)
Field: Materials Science — Materials Chemistry

Boosting solid oxide electrolyzer performance by fine tuning the microstructure of electrodes – Preliminary study This paper addresses the concept of adjusting the microstructure of the supports of solid oxide electrolyzers in order to boost performance. While several earlier studies focused on maximizing performance, reducing degradation, adjusting operating conditions and introducing new materials or designs of electrolysis stack, the current study addresses potential improvement of the cell by fine tuning the microstructure without any major redesign of existing cells. In the proposed approach, the study combined numerical simulations with definition of the model, which can aid in predicting the performance of a cell with adjusted porosity of the electrode support, and preparation of modified cells with alternative pore forming agents and two alternative sintering temperature levels. Supports of solid oxide cells were sintered at 1350 and 1400 °C with pore former content of 25–35%. This resulted in the porosity of supports being in the range of 47–54%. Cells with 10Sc1CeSZ and 8YSZ electrolytes were investigated in operando. The proposed approach makes it possible to quantitatively and qualitatively assess the potential gain when the reference cell is slightly modified, according to guidelines obtained from the model. It was found that the proposed method to fine tune the microstructure can result in improved performance, with a clear indication that adjusting the sintering temperature has a stronger effect on the microstructure of the support than increasing the pore forming agent. Microstructure ; Materials science ; Porosity ; Electrolysis ; Sintering ; Oxide ; Stack (abstract data type) ; Electrode ; Electrolyte ; Chemical engineering ; Solid oxide fuel cell ; Electrolytic cell ; Composite material ; Computer science ; Metallurgy ; Chemistry Advancements in Solid Oxide Fuel Cells ; Chemical Looping and Thermochemical Processes ; Molten salt chemistry and electrochemical processes
Authors: Liane M. Moreau | Ekaterina Lapsheva | Jorge Iván Amaro-Estrada | Michael R. Gau | Patrick J. Carroll | Brian C. Manor | Yusen Qiao | Qiaomu Yang | Wayne W. Lukens | Dimosthenis Sokaras | Eric J. Schelter | Laurent Maron | Corwin H. Booth
Source: Chemical Science (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Electronic structure studies reveal 4f/5d mixing and its effect on bonding characteristics in Ce-imido and -oxo complexes This study presents the role of 5d orbitals in the bonding, and electronic and magnetic structure of Ce imido and oxo complexes synthesized with a tris(hydroxylaminato) [((2- <sup><i>t</i></sup> BuNO)C<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>)<sub>3</sub>N]<sup>3-</sup> (TriNO <sub><i>x</i></sub> <sup>3-</sup>) ligand framework, including the reported synthesis and characterization of two new alkali metal-capped Ce oxo species. X-ray spectroscopy measurements reveal that the imido and oxo materials exhibit an intermediate valent ground state of the Ce, displaying hallmark features in the Ce L<sub>III</sub> absorption of partial f-orbital occupancy that are relatively constant for all measured compounds. These spectra feature a double peak consistent with other formal Ce(iv) compounds. Magnetic susceptibility measurements reveal enhanced levels of temperature-independent paramagnetism (TIP). In contrast to systems with direct bonding to an aromatic ligand, no clear correlation between the level of TIP and f-orbital occupancy is observed. CASSCF calculations defy a conventional van Vleck explanation of the TIP, indicating a single-reference ground state with no low-lying triplet excited state, despite accurately predicting the measured values of f-orbital occupancy. The calculations do, however, predict strong 4f/5d hybridization. In fact, within these complexes, despite having similar f-orbital occupancies and therefore levels of 4f/5d hybridization, the d-state distributions vary depending on the bonding motif (Ce[double bond, length as m-dash]O <i>vs.</i> Ce[double bond, length as m-dash]N) of the complex, and can also be fine-tuned based on varying alkali metal cation capping species. This system therefore provides a platform for understanding the characteristic nature of Ce multiple bonds and potential impact that the associated d-state distribution may have on resulting reactivity. Mixing (physics) ; Crystallography ; Chemical physics ; Chemistry ; Materials science ; Computational chemistry ; Physics ; Quantum mechanics Organometallic Complex Synthesis and Catalysis ; Lanthanide and Transition Metal Complexes ; Magnetism in coordination complexes
Authors: Heba M. Aboud | Amal K. Hussein | Abdallah Z. Zayan | Tarek Saad Makram | Mona O. Sarhan | Dina M. El-Sharawy
Source: Pharmaceutics (article, 2022-04-16)
Field: Materials Science — Biomaterials

Tailoring of Selenium-Plated Novasomes for Fine-Tuning Pharmacokinetic and Tumor Uptake of Quercetin: In Vitro Optimization and In Vivo Radiobiodistribution Assessment in Ehrlich Tumor-Bearing Mice Quercetin (QRC) is a bioflavonoid with anti-inflammatory, antioxidant, and anticancer activities, yet QRC poor bioavailability has hampered its clinical implementation. The aim of the current work was to harness novasomes (NOVs), free fatty acid enriched vesicles, as a novel nano-cargo for felicitous QRC delivery with subsequent functionalization with selenium (SeNOVs), to extend the systemic bio-fate of NOVs and potentiate QRC anticancer efficacy through the synergy with selenium. QRC-NOVs were primed embedding oleic acid, Brij 35, and cholesterol adopting thin-film hydration technique according to Box-Behnken design. Employing Design-Expert<sup>®</sup> software, the impact of formulation variables on NOVs physicochemical characteristics besides the optimum formulation election were explored. Based on the optimal NOVs formulation, QRC-SeNOVs were assembled via electrostatic complexation/in situ reduction method. The MTT cytotoxicity assay of the uncoated, and coated nanovectors versus crude QRC was investigated in human rhabdomyosarcoma (RD) cells. The in vivo pharmacokinetic and biodistribution studies after intravenous administrations of technetium-99m (<sup>99m</sup>Tc)-labeled QRC-NOVs, QRC-SeNOVs, and QRC-solution were scrutinized in Ehrlich tumor-bearing mice. QRC-NOVs and QRC-SeNOVs disclosed entrapment efficiency of 67.21 and 70.85%, vesicle size of 107.29 and 129.16 nm, ζ potential of -34.71 and -43.25 mV, and accumulatively released 43.26 and 31.30% QRC within 24 h, respectively. Additionally, QRC-SeNOVs manifested a far lower IC<sub>50</sub> of 5.56 μg/mL on RD cells than that of QRC-NOVs (17.63 μg/mL) and crude QRC (38.71 μg/mL). Moreover, the biodistribution study elicited higher preferential uptake of <sup>99m</sup>Tc-QRC-SeNOVs within the tumorous tissues by 1.73- and 5.67-fold as compared to <sup>99m</sup>Tc-QRC-NOVs and <sup>99m</sup>Tc-QRC-solution, respectively. Furthermore, the relative uptake efficiency of <sup>99m</sup>Tc-QRC-SeNOVs was 5.78, the concentration efficiency was 4.74 and the drug-targeting efficiency was 3.21. Hence, the engineered QRC-SeNOVs could confer an auspicious hybrid nanoparadigm for QRC delivery with fine-tuned pharmacokinetics, and synergized antitumor traits. Chemistry ; In vivo ; Biodistribution ; Nuclear chemistry ; In vitro ; Biochemistry ; Biology ; Biotechnology Nanoparticle-Based Drug Delivery ; Protein Interaction Studies and Fluorescence Analysis ; Advancements in Transdermal Drug Delivery
Authors: Matthew J. Sis | Zhou Ye | Katherine La Costa | Matthew J. Webber
Source: ACS Nano (article, 2022-05-31)
Field: Materials Science — Biomaterials

Energy Landscapes of Supramolecular Peptide–Drug Conjugates Directed by Linker Selection and Drug Topology Peptide-drug conjugates that self-assemble into supramolecular nanomaterials have promise for uses in drug delivery. These discrete molecular species offer high and precise drug loading, affording efficient carriers for various therapeutic agents. Their peptide modules, meanwhile, enable biological targeting and stimuli-responsive function while also ordering the assembled nanostructure. The often hydrophobic drug payload likewise acts as a directive for self-assembly in aqueous media. Though accessible synthetic methods have allowed for extensive exploration of the peptide design space, the specific contributions of the drug molecule and its linker to the resulting assembly have been less explored. Hydrophobic drugs frequently have planar domains, conjugated π-systems, and isolated polar groups, which in turn can lead to specific and directional self-interactions. These energies of interaction affect the free energy landscape of self-assembly and may impact the form and assembly process of the desired nanomaterial. Here, two model supramolecular peptide-drug conjugates (sPDCs) are explored, composed of the corticosteroid dexamethasone conjugated to a conserved peptide sequence via two different linker chemistries. The choice of linker, which alters the orientation, rotational freedom, and number of stereoisomers of the prodrug in the final sPDC, impacts the mechanism and energetic barrier of assembly as well as the nano/macroscale properties of the resultant supramolecular materials. Accordingly, this work demonstrates the nonzero energetic contributions of the drug and its linker to sPDC self-assembly, provides a quantitative exploration of the sPDC free energy landscape, and suggests design principles for the enhanced control of sPDC nanomaterials to inform future applications as therapeutic drug carriers. Linker ; Peptide ; Supramolecular chemistry ; Nanomaterials ; Conjugated system ; Combinatorial chemistry ; Nanotechnology ; Materials science ; Conjugate ; Drug delivery ; Energy landscape ; Self-assembly ; Prodrug ; Chemistry ; Molecule ; Computer science ; Organic chemistry ; Polymer ; Biochemistry Supramolecular Self-Assembly in Materials ; Polydiacetylene-based materials and applications ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Max Hohenschutz | Pierre Bauduin | Carlos G. Lopez | Beate Förster | Walter Richtering
Source: Angewandte Chemie International Edition (article, 2022-11-08)
Field: Materials Science — Materials Chemistry

Superchaotropic Nano‐ion Binding as a Gelation Motif in Cellulose Ether Solutions Nanometer-sized anions (nano-ions) like polyoxometalates and boron clusters exhibit so-called superchaotropic behavior, which describes their strong binding to hydrated non-ionic matter in water. We show here that nano-ions, at millimolar concentrations, dramatically enhance the viscosity and induce gelation of aqueous solutions of non-ionic cellulose ethers (CEs), a class of widely utilized polymers known for their thickening and gel-forming ability. These phenomena arise from an interplay of attractive forces and repulsive electrostatic forces between CE-chains upon nano-ion binding. The attractive forces manifest themselves as aggregation of CE-chains into a physically crosslinked polymer network (gel). In turn, the electrostatic repulsions hamper the viscosity increase and gelation. Superchaotropic nano-ion binding emerges as a novel and general physical crosslinking motif for CE-solutions and exceeds by far the conventional thickening effects of classical salts and ionic surfactants. Aqueous solution ; Ion ; Ionic bonding ; Polymer ; Nanometre ; Nano- ; Chemistry ; Viscosity ; Electrostatics ; Polyelectrolyte ; Ether ; Cellulose ; Chemical engineering ; Polymer chemistry ; Chemical physics ; Materials science ; Organic chemistry ; Physical chemistry ; Composite material Polyoxometalates: Synthesis and Applications ; Supramolecular Self-Assembly in Materials ; Pickering emulsions and particle stabilization
Authors: José D. Gouveia | Ángel Morales‐García | Francesc Viñes | José R. B. Gomes | Francesc Illas
Source: ACS Nano (article, 2022-07-22)
Field: Materials Science — Materials Chemistry

MXenes <i>à la Carte</i>: Tailoring the Epitaxial Growth Alternating Nitrogen and Transition Metal Layers A high-throughput analysis based on density functional simulations underscores the viable epitaxial growth of MXenes by alternating nitrogen and metal adlayers. This is supported by an exhaustive analysis of a number of thermodynamic and kinetic thresholds belonging to different critical key steps in the course of the epitaxial growth. The results on 18 pristine N- and C-based MXenes with M<sub>2</sub>X stoichiometry reveal an easy initial N<sub>2</sub> fixation and dissociation, where N<sub>2</sub> adsorption is controlled by the MXene surface charge and metal d-band center and its dissociation controlled by the reaction energy change. Furthermore, formation energies indicate the plausible formation of N-terminated M<sub>2</sub>XN<sub>2</sub> MXenes. Moreover, the further covering with metal adlayers is found to be thermodynamically driven and stable, especially when using early transition metal atoms. The most restrictive analyzed criterion is the N<sub>2</sub> adsorption and dissociation at nearly full N-covered adlayers, which is yet achievable for almost half of the explored M<sub>2</sub>X seeds. The present results unfold the possibility of expanding, controlling, and tuning the composition, width, and structure of the MXene family. MXenes ; Dissociation (chemistry) ; Chemical physics ; Materials science ; Epitaxy ; Transition metal ; Metal ; Stoichiometry ; Kinetic energy ; Adsorption ; Nitrogen ; Nanotechnology ; Physical chemistry ; Chemistry ; Catalysis ; Layer (electronics) ; Physics MXene and MAX Phase Materials ; Advanced Photocatalysis Techniques ; 2D Materials and Applications
Authors: Chiara Dal Bosco | Francesca Marıanı | Alessandra Gentili
Source: Molecules (article, 2022-01-28)
Field: Chemistry — Analytical Chemistry

Hydrophobic Eutectic Solvent-Based Dispersive Liquid-Liquid Microextraction Applied to the Analysis of Pesticides in Wine A green solvent-based DLLME/HPLC-MS method for the determination of 19 pesticides in wine samples has been developed. The extractant solvent is a hydrophobic eutectic mixture composed of L-menthol and butylated hydroxytoluene in a molar ratio of 3:1. The endogenous ethanol of wine has been used as dispersive solvent, in order to avoid the solidification of the extracts under 19 °C. The mobile phase composition, the elution gradient and the sample injection volume were optimized in order to make this hydrophobic mixture compatible with conventional reversed phase chromatography and electrospray ionization. The method was validated in matrix, using a wine free from the target compounds. Average recovery as high as 80%, precision between 3 and 14%, and limits of detection and quantification much lower than the maximum residue levels (MRLs) for grapes and wines fixed by the EU regulation, make this multiresidue method fitted for the purpose, with the further advantages of being quick, cheap and in compliance with the green analytical chemistry. From the analysis of 11 commercial wines it was found that just in a bio sample the target compounds were not detectable or lower than quantification limit; as for the other samples, the most widespread and abundant pesticides were methoxyfenozide and boscalid, but their levels were much lower than the relative MRLs. Chromatography ; Wine ; Chemistry ; Solvent ; Detection limit ; Deep eutectic solvent ; Butylated hydroxytoluene ; Menthol ; High-performance liquid chromatography ; Eutectic system ; Organic chemistry ; Antioxidant Analytical chemistry methods development ; Pesticide Residue Analysis and Safety ; Analytical Chemistry and Chromatography