jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sergio de-la-Huerta-Sainz | Ángel Ballesteros | Nicolás A. Cordero
Source: Nanomaterials (article, 2022-12-25)
Field: Materials Science — Materials Chemistry

Gaussian Curvature Effects on Graphene Quantum Dots In the last few years, much attention has been paid to the exotic properties that graphene nanostructures exhibit, especially those emerging upon deforming the material. Here we present a study of the mechanical and electronic properties of bent hexagonal graphene quantum dots employing density functional theory. We explore three different kinds of surfaces with Gaussian curvature exhibiting different shapes-spherical, cylindrical, and one-sheet hyperboloid-used to bend the material, and several boundary conditions regarding what atoms are forced to lay on the chosen surface. In each case, we study the curvature energy and two quantum regeneration times (classic and revival) for different values of the curvature radius. A strong correlation between Gaussian curvature and these regeneration times is found, and a special divergence is observed for the revival time for the hyperboloid case, probably related to the pseudo-magnetic field generated by this curvature being capable of causing a phase transition. Graphene ; Quantum dot ; Gaussian curvature ; Curvature ; Gaussian ; Physics ; Statistical physics ; Quantum mechanics ; Materials science ; Mathematics ; Geometry Graphene research and applications ; Graphene and Nanomaterials Applications ; Carbon and Quantum Dots Applications
Authors: Aneta Pospíšilová | Juraj Vodička | Monika Trudičová | Zuzana Juglova | Jiří­ Smilek | Přemysl Menčík | Jiří Másilko | Eva Slaninová | Veronika Melčová | Michal Kalina | Stanislav Obruča | Petr Sedláček
Source: Polymers (article, 2022-05-13)
Field: Materials Science — Biomaterials

Effects of Differing Monomer Compositions on Properties of P(3HB-co-4HB) Synthesized by Aneurinibacillus sp. H1 for Various Applications Films prepared from poly(3-hydroxybutyrate-<i>co</i>-4-hydroxybutyrate) copolymers produced by <i>Aneurinibacillus</i> sp. H1 using an automatic film applicator were homogeneous and had a defined thickness, which allowed a detailed study of physicochemical properties. Their properties were compared with those of a poly (3-hydroxybutyrate) homopolymer film prepared by the same procedure, which proved to be significantly more crystalline by DSC and XRD. Structural differences between samples had a major impact on their properties. With increasing 4-hydroxybutyrate content, the ductility and release rate of the model hydrophilic active ingredient increased significantly. Other observed properties, such as the release of the hydrophobic active substance, the contact angle with water and ethylene glycol, or the surface morphology and roughness, were also affected by the composition. The identified properties predetermine these copolymers for wide use in areas such as biomedicine or smart biodegradable packaging for food or cosmetics. The big advantage is the possibility of fine-tuning properties simply by changing the fermentation conditions. Materials science ; Copolymer ; Chemical engineering ; Ethylene glycol ; Contact angle ; Monomer ; Morphology (biology) ; Homogeneous ; Surface roughness ; Polymer chemistry ; Polymer ; Composite material biodegradable polymer synthesis and properties ; Microplastics and Plastic Pollution ; Biopolymer Synthesis and Applications
Authors: Albert M. Schulte | Dušan Kolarski | Vidya Sundaram | Ashutosh Srivastava | Florence Tama | Ben L. Feringa | Wiktor Szymański
Source: International Journal of Molecular Sciences (article, 2022-05-10)
Field: Materials Science — Materials Chemistry

Light-Control over Casein Kinase 1δ Activity with Photopharmacology: A Clear Case for Arylazopyrazole-Based Inhibitors Protein kinases are responsible for healthy cellular processes and signalling pathways, and their dysfunction is the basis of many pathologies. There are numerous small molecule inhibitors of protein kinases that systemically regulate dysfunctional signalling processes. However, attaining selectivity in kinase inhibition within the complex human kinome is still a challenge that inspires unconventional approaches. One of those approaches is photopharmacology, which uses light-controlled bioactive molecules to selectively activate drugs only at the intended space and time, thereby avoiding side effects outside of the irradiated area. Still, in the context of kinase inhibition, photopharmacology has thus far been rather unsuccessful in providing light-controlled drugs. Here, we present the discovery and optimisation of a photoswitchable inhibitor of casein kinase 1δ (CK1δ), important for the control of cell differentiation, circadian rhythm, DNA repair, apoptosis, and numerous other signalling processes. Varying the position at which the light-responsive azobenzene moiety has been introduced into a known CK1δ inhibitor, LH846, revealed the preferred regioisomer for efficient photo-modulation of inhibitory activity, but the photoswitchable inhibitor suffered from sub-optimal (photo)chemical properties. Replacement of the bis-phenyl azobenzene group with the arylazopyrazole moiety yielded a superior photoswitch with very high photostationary state distributions, increased solubility and a 10-fold difference in activity between irradiated and thermally adapted samples. The reasons behind those findings are explored with molecular docking and molecular dynamics simulations. Results described here show how the evaluation of privileged molecular architecture, followed by the optimisation of the photoswitchable unit, is a valuable strategy for the challenging design of the photoswitchable kinase inhibitors. Casein kinase 1 ; Kinase ; Kinome ; Azobenzene ; Chemistry ; Context (archaeology) ; Photoswitch ; Small molecule ; Biochemistry ; Protein kinase A ; Computational biology ; Biology ; Biophysics ; Cell biology ; Molecule Photochromic and Fluorescence Chemistry ; Photoreceptor and optogenetics research ; Neurobiology and Insect Physiology Research
Authors: О.A. Balitskii | Oleksandr Mashkov | Anastasiia Barabash | Viktor Rehm | Hany A. Afify | Ning Li | Maria S. Hammer | Christoph J. Brabec | Andreas Eigen | Marcus Halik | Olesya Yarema | Maksym Yarema | Vanessa Wood | David Stifter | Wolfgang Heiß
Source: Nanomaterials (article, 2022-10-04)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Ligand Tuning of Localized Surface Plasmon Resonances in Antimony-Doped Tin Oxide Nanocrystals Aliovalent-doped metal oxide nanocrystals exhibiting localized surface plasmons (LSPRs) are applied in systems that require reflection/scattering/absorption in infrared and optical transparency in visible. Indium tin oxide (ITO) is currently leading the field, but indium resources are known to be very restricted. Antimony-doped tin oxide (ATO) is a cheap candidate to substitute the ITO, but it exhibits less advantageous electronic properties and limited control of the LSPRs. To date, LSPR tuning in ATO NCs has been achieved electrochemically and by aliovalent doping, with a significant decrease in doping efficiency with an increasing doping level. Here, we synthesize plasmonic ATO nanocrystals (NCs) via a solvothermal route and demonstrate ligand exchange to tune the LSPR energies. Attachment of ligands acting as Lewis acids and bases results in LSPR peak shifts with a doping efficiency overcoming those by aliovalent doping. Thus, this strategy is of potential interest for plasmon implementations, which are of potential interest for infrared upconversion, smart glazing, heat absorbers, or thermal barriers. Materials science ; Doping ; Plasmon ; Surface plasmon resonance ; Nanocrystal ; Indium tin oxide ; Indium ; Nanotechnology ; Oxide ; Surface plasmon ; Antimony ; Localized surface plasmon ; Optoelectronics ; Nanoparticle ; Layer (electronics) Gold and Silver Nanoparticles Synthesis and Applications ; ZnO doping and properties ; Copper-based nanomaterials and applications
Authors: Tânia Peixoto | Joana B. Nunes | M.A. Lopes | Elina Marinho | M. Fernanda R. P. Proença | Paulo E. Lopes | María C. Paiva
Source: Polymer Composites (article, 2022-09-07)
Field: Materials Science — Biomaterials

Poly(lactic acid) composites with few layer graphene produced by noncovalent chemistry Abstract In recent years, significant attention has been given to “green” product innovation and related manufacturing processes. This work reports the preparation of few‐layer graphene (FLG) and respective PLA‐based composites by an eco‐friendly, efficient, and cost‐effective approach. FLG was produced in a scaled‐up process, based on the noncovalent functionalization of a micronized graphite with a pyrene derivate (PY), in aqueous solution. The exfoliation degree, morphology, and thermal stability of the exfoliated material were evaluated. Then, the influence of the pristine graphite and FLG on the morphology, crystallinity, thermal and mechanical properties of PLA composites produced by melt mixing is reported for the first time. The composites prepared with the lowest loading of 0.05 wt% demonstrated suitability for further processing for potential applications where product safety is crucial, such as in biomedicine. Materials science ; Graphene ; Exfoliation joint ; Crystallinity ; Composite material ; Graphite ; Thermal stability ; Surface modification ; Aqueous suspension ; Morphology (biology) ; Aqueous solution ; Chemical engineering ; Nanotechnology ; Organic chemistry ; Chemistry biodegradable polymer synthesis and properties ; Graphene and Nanomaterials Applications ; Bone Tissue Engineering Materials
Authors: Jacopo De Maron | Rodolfo Mafessanti | Pio Gramazio | Elisabetta Orfei | Andrea Fasolini | Francesco Basile
Source: Nanomaterials (article, 2022-12-22)
Field: Materials Science — Materials Chemistry

H2 Production by Methane Oxy-Reforming: Effect of Catalyst Pretreatment on the Properties and Activity of Rh-Ce0.5Zr0.5O2 Synthetized by Microemulsion Green hydrogen introduction in hard-to-abate processes is held back by the cost of substituting steam reforming plants with electrolyzers. However, green hydrogen can be integrated in properly modified reforming processes. The process proposed here involves the substitution of steam reforming with oxy-reforming, which is the coupling of the former with catalytic partial oxidation (CPO), exploiting the pure oxygen coproduced during electrolysis to feed CPO, which allows for better heat exchange thanks to its exothermic nature. With the aim of developing tailored catalysts for the oxy-reforming process, Ce<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> was synthetized by microemulsion and impregnated with Rh. The Ce-based supports were calcined at different temperatures (750 and 900 °C) and the catalysts were reduced at 750 °C or 500 °C. Tuning the calcination temperature allowed for an increase in the support surface area, resulting in well-dispersed Rh species that provided a high reducibility for both the metal active phase and the Ce-based support. This allowed for an increase in methane conversion under different conditions of contact time and pressure and the outperformance of the other catalysts. The higher activity was related to well-dispersed Rh species interacting with the support that provided a high concentration of surface OH* on the Ce-based support and increased methane dissociation. This anticipated the occurrence and the extent of steam reforming over the catalytic bed, producing a smoother thermal profile. Steam reforming ; Catalysis ; Hydrogen production ; Methane reformer ; Calcination ; Methane ; Chemical engineering ; Syngas ; Partial oxidation ; Hydrogen ; Electrolysis ; Materials science ; Microemulsion ; Exothermic reaction ; Chemistry ; Inorganic chemistry ; Organic chemistry ; Physical chemistry ; Electrode Catalytic Processes in Materials Science ; Catalysts for Methane Reforming ; Catalysis and Oxidation Reactions
Authors: Zihnil Adha Islamy Mazrad | May C. Lai | Thomas P. Davis | Joseph A. Nicolazzo | Kristofer J. Thurecht | Meike N. Leiske | Kristian Kempe
Source: Polymer Chemistry (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Protected amine-functional initiators for the synthesis of α-amine homo- and heterotelechelic poly(2-ethyl-2-oxazoline)s Screening a series of protected amine cationic ring-opening polymerization initiators revealed the commercially available N -(3-bromopropyl)phthalimide as the most suitable to achieve defined polymers with high degree of amine functionalization. Amine gas treating ; Phthalimide ; Cationic polymerization ; Oxazoline ; Chemistry ; Polymer chemistry ; Polymerization ; Surface modification ; Polymer ; Combinatorial chemistry ; Organic chemistry ; Catalysis Advanced Polymer Synthesis and Characterization ; biodegradable polymer synthesis and properties ; Synthetic Organic Chemistry Methods
Authors: Siiri Bienz | Sophie H. van Vreeswijk | Yashashwa Pandey | Giovanni Luca Bartolomeo | Bert M. Weckhuysen | Renato Zenobi | Naresh Kumar
Source: Catalysis Science & Technology (article, 2022-01-01)
Field: Chemistry — Inorganic Chemistry

Probing coke formation during the methanol-to-hydrocarbon reaction on zeolite ZSM-5 catalyst at the nanoscale using tip-enhanced fluorescence microscopy The deactivation mechanism of the widely used zeolite ZSM-5 catalysts remains unclear to date due to the lack of analytical techniques with sufficient sensitivity and/or spatial resolution. Herein, a combination of hyperspectral confocal fluorescence microscopy (CFM) and tip-enhanced fluorescence (TEFL) microscopy is used to study the formation of different coke (precursor) species involved in the deactivation of zeolite ZSM-5 during the methanol-to-hydrocarbon (MTH) reaction. CFM submicron-scale imaging shows a preferential formation of graphite-like coke species at the edges of zeolite ZSM-5 crystals within 10 min of the MTH reaction (<i>i.e.</i>, working catalyst), whilst the amount of graphite-like coke species uniformly increased over the entire zeolite ZSM-5 surface after 90 min (<i>i.e.</i>, deactivated catalyst). Furthermore, TEFL nanoscale imaging with ∼35 nm spatial resolution revealed that formation of coke species on the zeolite ZSM-5 surface is non-uniform and a relatively larger amount of coke is formed at the crystal steps, indicating a higher initial catalytic activity. Coke ; Zeolite ; Catalysis ; ZSM-5 ; Nanoscopic scale ; Graphite ; Chemical engineering ; Fluorescence ; Methanol ; Chemistry ; Hydrocarbon ; Materials science ; Nanotechnology ; Organic chemistry ; Optics Zeolite Catalysis and Synthesis ; Surface Chemistry and Catalysis ; Mesoporous Materials and Catalysis
Authors: Mitchell T. Blyth | Michelle L. Coote
Source: Physical Chemistry Chemical Physics (article, 2022-12-08)
Field: Chemistry — Organic Chemistry

Manipulation of N-heterocyclic carbene reactivity with practical oriented electric fields Using density functional theory (DFT) calculations, we demonstrate that the organocatalytic properties of NHCs, such as their nucleophilicity, electrophilicity and singlet triplet gaps, are predictably influenced by electric fields. These electric fields can be delivered in practical systems using charged functional groups to provide designed local electric fields, and their effects are strong enough to be synthetically relevant even in relatively polar solvents. We also show that these electrostatically enhanced NHCs elicit dramatic changes in the energetics of key transition states of a model benzoin condensation in various solvents, which can be tuned by the sign of the applied charge and the solvent polarity. Based on these findings, we suggest that NHCs are plausible candidates for electrostatic catalysts, and that electric field effects should be considered when designing NHC frameworks. Electric field ; Density functional theory ; Carbene ; Chemistry ; Chemical physics ; Computational chemistry ; Electrophile ; Solvent effects ; Reactivity (psychology) ; Nucleophile ; Electrostatics ; Singlet state ; Solvent ; Catalysis ; Organic chemistry ; Physics ; Physical chemistry ; Atomic physics ; Excited state ; Quantum mechanics N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions ; Ammonia Synthesis and Nitrogen Reduction
Authors: Julian Schmid | Meng Wang | Oliver Y. Gutiérrez | R. Morris Bullock | Donald M. Camaioni | Johannes A. Lercher
Source: Angewandte Chemie International Edition (article, 2022-04-28)
Field: Chemistry — Inorganic Chemistry

Controlling Reaction Routes in Noble‐Metal‐Catalyzed Conversion of Aryl Ethers Hydrogenolysis and hydrolysis of aryl ethers in the liquid phase are important reactions for accessing functionalized cyclic compounds from renewable feedstocks. On supported noble metals, hydrogenolysis is initiated by a hydrogen addition to the aromatic ring followed by C-O bond cleavage. In water, hydrolysis and hydrogenolysis proceed by partial hydrogenation of the aromatic ring prior to water or hydrogen insertion. The mechanisms are common for the studied metals, but the selectivity to hydrogenolysis increases in the order Pd<Rh<Ir<Ru≈Pt in decalin and water; the inverse was observed for the selectivity to hydrolysis in water. Hydrogenolysis selectivity correlates with the Gibbs free energy of hydrogen adsorption. Hydrogenolysis has the highest standard free energy of activation and a weak dependence on H<sub>2</sub> pressure, thus, the selectivity to hydrogenolysis is maximized by increasing temperature and decreasing H<sub>2</sub> pressure. Selectivity to C-O bond cleavage reaches >95 % in water and alkaline conditions. Hydrogenolysis ; Chemistry ; Catalysis ; Selectivity ; Bond cleavage ; Aryl ; Hydrolysis ; Inorganic chemistry ; Organic chemistry Asymmetric Hydrogenation and Catalysis ; Catalysis for Biomass Conversion ; Catalysis and Hydrodesulfurization Studies
Authors: Jesang Lee | Seung Bum Park
Source: Pharmaceuticals (review, 2022-11-27)
Field: Chemistry — Organic Chemistry

Extended Applications of Small-Molecule Covalent Inhibitors toward Novel Therapeutic Targets Recently, small-molecule covalent inhibitors have been accepted as a practical tool for targeting previously "undruggable" proteins. The high target selectivity of modern covalent inhibitors is now alleviating toxicity concerns regarding the covalent modifications of proteins. However, despite the tremendous clinical success of current covalent inhibitors, there are still unmet medical needs that covalent inhibitors have not yet addressed. This review categorized representative covalent inhibitors based on their mechanism of covalent inhibition: conventional covalent inhibitors, targeted covalent inhibitors (TCIs), and expanded TCIs. By reviewing both Food and Drug Administration (FDA)-approved drugs and drug candidates from recent literature, we provide insight into the future direction of covalent inhibitor development. Covalent bond ; Small molecule ; Covalent binding ; Chemistry ; Drug discovery ; Pharmacology ; Combinatorial chemistry ; Biochemistry ; Medicine Click Chemistry and Applications ; Protein Degradation and Inhibitors ; Peptidase Inhibition and Analysis
Authors: Hashim Alhmoud | Mohammed Alkhaled | Batuhan E. Kaynak | M. Selim Hanay
Source: Lab on a Chip (article, 2022-11-25)
Field: Materials Science — Biomaterials

Leveraging the elastic deformability of polydimethylsiloxane microfluidic channels for efficient intracellular delivery With the rapid development of microfluidic based cell therapeutics systems, the need arises for compact, modular, and microfluidics-compatible intracellular delivery platforms with small footprints and minimal operational requirements. Physical deformation of cells passing through a constriction in a microfluidic channel has been shown to create transient membrane perturbations that allow passive diffusion of materials from the outside to the interior of the cell. This mechanical approach to intracellular delivery is simple to implement and fits the criteria outlined above. However, available microfluidic platforms that operate through this mechanism are traditionally constructed from rigid channels with fixed dimensions that suffer from irreversible clogging and incompatibility with larger size distributions of cells. Here we report a flexible and elastically deformable microfluidic channel, and we leverage this elasticity to dynamically generate temporary constrictions with any given size within the channel width parameters. Additionally, clogging is prevented by increasing the size of the constriction momentarily to allow clogs to pass. By tuning the size of the constriction appropriately, we show the successful delivery of GFP-coding plasmids to the interior of three mammalian cell lines and fluorescent gold nanoparticles to HEK293 FT cells all the while maintaining a high cell viability rate. We also demonstrate the device capabilities by systematically identifying the optimum constriction size that maximizes the intracellular delivery efficiency of FITC-dextran for three different cell lines. This development will no doubt lead to miniaturized intracellular delivery microfluidic components that can be easily integrated into larger lab-on-a-chip systems for future cell modification devices. Polydimethylsiloxane ; Microfluidics ; Intracellular ; Nanotechnology ; Materials science ; Biomedical engineering ; Chemistry ; Engineering ; Biochemistry Electrospun Nanofibers in Biomedical Applications ; RNA Interference and Gene Delivery ; 3D Printing in Biomedical Research
Authors: Abhishek Kumar Singh | Boris Schade | Marta Rosati | Rashmi Rashmi | Valentina Dichiarante | Gabriella Cavallo | Pierangelo Metrangolo | Rainer Haag
Source: Macromolecular Bioscience (article, 2022-05-25)
Field: Materials Science — Polymers and Plastics

Synthesis and Linker‐Controlled Self‐Assembly of Dendritic Amphiphiles with Branched Fluorinated Tails Amphiphiles containing fluorinated segments tend to aggregate in the aqueous solution into structure of lower curvature than their hydrocarbon analogs due to their larger diameter. A benefit of supramolecular structures incorporating fluorine moieties is their high electron density, which can be viewed in cryo-TEM with better contrast than their hydrogenated forms. A modular approach has been developed for the synthesis of a new family of nonionic branched amphiphiles consisting of oligoglycerol units (G2) as the hydrophilic part and a branched fluorinated (F27) hydrophobic part. The design of this hydrophobic moiety allows to achieve a higher fluorine density than the previously used straight-chain perfluoroalkanes. Two different chemical approaches, amide, and triazole, are used to link the hydrophilic and hydrophobic segments. In addition, the aggregation behavior is investigated by dynamic light scattering (DLS) and cryo-TEM. The measurements prove the formation of multivesicular (MVVs) and multilamellar (MLVs) vesicles as well as smaller unilamellar vesicles. Further, the cell viability test proves the low cell toxicity of these nanoarchitectures for potential biomedical applications. Amphiphile ; Chemistry ; Vesicle ; Dynamic light scattering ; Supramolecular chemistry ; Moiety ; Self-assembly ; Linker ; Contact angle ; Aqueous solution ; Hydrophobic effect ; Polymer chemistry ; Organic chemistry ; Membrane ; Chemical engineering ; Copolymer ; Nanotechnology ; Nanoparticle ; Molecule ; Materials science ; Polymer Dendrimers and Hyperbranched Polymers ; Supramolecular Self-Assembly in Materials ; Luminescence and Fluorescent Materials