jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Marc Wolter | Mirna Maalouf | M. Janek | Cornelius Knappe | Markus Krämer | Michael Lämmerhofer
Source: Journal of Separation Science (article, 2024-12-01)
Field: Chemistry — Spectroscopy

Triphenyl‐Modified Mixed‐Mode Stationary Phases With and Without Embedded Ion‐Exchange Sites for High‐Performance Liquid Chromatography The present work reports on the preparation, characterization, and evaluation of a set of novel triphenyl-modified silica-based stationary phases without and with embedded ion-exchange sites for mixed-mode liquid chromatography. The three synthesized triphenyl phases differed in additionally incorporated ion-exchange sites. In one embodiment, allyltriphenylsilane was bonded to thiol-modified silica by thiol-ene click reaction, leading to particles with no ion-exchange sites. A second stationary phase was obtained by thiol-yne click reaction of thiol silica with 2-propinyl-triphenylphosphonium bromide, yielding a strong anion-exchanger (SAX). A third stationary phase was obtained from this SAX phase by the oxidation of residual thiols to sulfonic acid moieties, leading to a zwitterionic surface. All synthesized materials were subjected to elemental analysis, <sup>13</sup>C and <sup>29</sup>Si solid-state cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy analysis, and pH-dependent ζ-potential determinations via electrophoretic light scattering. The prepared stationary phases were chromatographically evaluated under classical reversed-phase, ion-exchange, and hydrophilic interaction chromatography conditions and classified within a set of commercially available columns by principal component analysis of retention factors. Finally, the obtained stationary phases were applied for biomolecule separations (e.g., teicoplanin and siRNA patisiran). These LC tests proved the orthogonality of the three prepared stationary phases and indicated possible fields of application. Chemistry ; Magic angle spinning ; Ion exchange ; Ion chromatography ; Hydrophilic interaction chromatography ; Analytical Chemistry (journal) ; Chromatography ; High-performance liquid chromatography ; Nuclear magnetic resonance spectroscopy ; Ion ; Organic chemistry Analytical Chemistry and Chromatography ; Microfluidic and Capillary Electrophoresis Applications ; Protein purification and stability
Authors: Laura Margarita Valencia‐Osorio | Mônica Lopes Aguiar | Mónica Álvarez-Láinez
Source: Journal of Applied Polymer Science (article, 2024-12-20)
Field: Materials Science — Biomaterials

Electrospinnability and Air Filtration Efficiency of <scp>PVDF</scp> Nanofibers: The Role of Electrospinning Solution Properties ABSTRACT This study successfully refined the electrospinnability window for polyvinylidene fluoride (PVDF) nanofiber membranes by systematically investigating solvent systems to achieve bead‐free morphologies mapped within a Teas ternary diagram. The correlation between fiber morphology and solution properties, such as viscosity, surface tension, and conductivity, allowed for a reproducible approach to fabricate high‐performance nanofiber membranes. Using DMSO:Ac/60:40 solvent ratio and a 14% w/w PVDF concentration, following a 3 2 factorial DoE, bead‐free fibers with an average diameter of ~700 nm were produced. This solvent selection and morphology refinement enhanced the crystalline β phase, which promoted intern‐oriented dipoles that were enhanced by an additional charge induction effect. This led to increased volume and surface charges on the membrane, enhancing electrostatic filtration mechanisms. Filtration tests at a 5.3 cm/s face velocity showed that a 10.4 g/m 2 bead‐free PVDF fiber membrane enriched with a β phase and additional induced surface charge, outperformed bead‐on‐string structures and a commercial high efficiency particulate air (HEPA) filter, achieving HEPA‐grade efficiencies with low air resistance . These results highlighted the role of morphology and charge characteristics in filtration efficiency and provided a method for PVDF electrospinning to meet the growing demand for effective ultrafine PM filtration. Electrospinning ; Nanofiber ; Filtration (mathematics) ; Materials science ; Chemical engineering ; Air filtration ; Fiber ; Polymer chemistry ; Polymer science ; Composite material ; Polymer ; Chemistry ; Organic chemistry ; Particulates ; Engineering Electrospun Nanofibers in Biomedical Applications ; Advanced Sensor and Energy Harvesting Materials ; Conducting polymers and applications
Authors: Abdelhak Lachguar | Iker Del Rosal | Laurent Maron | Erwann Jeanneau | Laurent Veyre | Chloé Thieuleux | Clément Camp
Source: Journal of the American Chemical Society (article, 2024-06-27)
Field: Chemistry — Organic Chemistry

π-Bonding of Group 11 Metals to a Tantalum Alkylidyne Alkyl Complex Promotes Unusual Tautomerism to Bis-alkylidene and CO<sub>2</sub> to Ketenyl Transformation A salt metathesis synthetic strategy is used to access rare tantalum/coinage metal (Cu, Ag, Au) heterobimetallic complexes. Specifically, complex [Li(THF)<sub>2</sub>][Ta(C<i><sup>t</sup></i>Bu)(CH<sub>2</sub><i><sup>t</sup></i>Bu)<sub>3</sub>], <b>1</b>, reacts with (IPr)MCl (M = Cu, Ag, Au, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to afford the alkylidyne-bridged species [Ta(CH<sub>2</sub><i><sup>t</sup></i>Bu)<sub>3</sub>(μ-C<i><sup>t</sup></i>Bu)M(IPr)] <b>2-M</b>. Interestingly, π-bonding of group 11 metals to the Ta─C moiety promotes a rare alkylidyne alkyl to bis-alkylidene tautomerism, in which compounds <b>2-M</b> are in equilibrium with [Ta(CH<i><sup>t</sup></i>Bu)(CH<sub>2</sub><i><sup>t</sup></i>Bu)<sub>2</sub>(μ-CH<i><sup>t</sup></i>Bu)M(IPr)] <b>3-M</b>. This equilibrium was studied in detail using NMR spectroscopy and computational studies. This reveals that the equilibrium position is strongly dependent on the nature of the coinage metal going down the group 11 triad, thus offering a new valuable avenue for controlling this phenomenon. Furthermore, we show that these uncommon bimetallic couples could open attractive opportunities for synergistic reactivity. We notably report an uncommon deoxygenative carbyne transfer to CO<sub>2</sub> resulting in rare examples of coinage metal ketenyl species, (<i><sup>t</sup></i>BuCCO)M(IPr), <b>4-M</b> (M = Cu, Ag, Au). In the case of the Ta/Li analogue <b>1</b>, the bis(alkylidene) tautomer is not detected, and the reaction with CO<sub>2</sub> does not cleanly yield ketenyl species, which highlights the pivotal role played by the coinage metal partner in controlling these unconventional reactions. Chemistry ; Tantalum ; Tautomer ; Alkyl ; Group (periodic table) ; Transformation (genetics) ; Stereochemistry ; Medicinal chemistry ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Carbon dioxide utilization in catalysis ; Catalytic Alkyne Reactions
Authors: Sooping Kok | Yun Ii Go | Xu Wang | M. L. Dennis Wong
Source: Nanomanufacturing (review, 2024-11-29)
Field: Materials Science — Materials Chemistry

A Review of Nanostructure Coating Techniques to Achieve High-Precision Optical Fiber Sensing Applications Optical fiber sensors have emerged as a critical sensing technology across various fields due to their advantages, including high potential bandwidth, electrical isolation that is safe for utilization in electrically hazardous environments, high reliability, and ease of maintenance. However, conventional optical fiber sensors face limitations in achieving high sensitivity and precision. The integration of nanostructures with advanced coating technology is one of the critical solutions to enhancing sensor functionality. This review examined nanostructure coating techniques that are compatible with optical fiber sensors and evaluated etching techniques for the improvement of optical fiber sensing technology. Techniques such as vapor deposition, laser deposition, and sputtering to coat the nanostructure of novel materials on the optical fiber sensors are analyzed. The ability of optical fiber sensors to interact with the environment via etching techniques is highlighted by comparing the sensing parameters between etched and bare optical fibers. This comprehensive overview aims to provide a detailed understanding of nanostructure coating and etching for optical fiber sensing and offer insights into the current state and future prospects of optical fiber sensor technology for sensing performance advancement, emphasizing its potential in future sensing applications and research directions. Nanostructure ; Materials science ; Coating ; Optical fiber ; Fiber ; Nanotechnology ; Optoelectronics ; Computer science ; Composite material ; Telecommunications Diamond and Carbon-based Materials Research ; Nanowire Synthesis and Applications ; Advanced Fiber Optic Sensors
Authors: Tao Li | Zhi-Jing Xu | Shuting Zhang | Jia Xu | Piaopiao Pan | Ning‐Yi Zhou
Source: Nature Communications (article, 2024-07-20)
Field: Materials Science — Materials Chemistry

Discovery of a Ni2+-dependent heterohexameric metformin hydrolase The biguanide drug metformin is a first-line blood glucose-lowering medication for type 2 diabetes, leading to its presence in the global environment. However, little is known about the fate of metformin by microbial catabolism. Here, we characterize a Ni<sup>2+</sup>-dependent heterohexameric enzyme (MetCaCb) from the ureohydrolase superfamily, catalyzing the hydrolysis of metformin into guanylurea and dimethylamine. Either subunit alone is catalytically inactive, but together they work as an active enzyme highly specific for metformin. The crystal structure of the MetCaCb complex shows the coordination of the binuclear metal cluster only in MetCa, with MetCb as a protein binder of its active cognate. An in-silico search and functional assay discover a group of MetCaCb-like protein pairs exhibiting metformin hydrolase activity in the environment. Our findings not only establish the genetic and biochemical foundation for metformin catabolism but also provide additional insights into the adaption of the ancient enzymes toward newly occurred substrate. Metformin ; Biguanide ; Hydrolase ; Enzyme ; Chemistry ; Biochemistry ; Protein subunit ; Type 2 Diabetes Mellitus ; Biology ; Diabetes mellitus ; Endocrinology ; Gene Enzyme Structure and Function ; Biochemical and Molecular Research ; Enzyme Catalysis and Immobilization
Authors: Dimitrios Valavanis | Paolo Ciocci | Ian J. McPherson | Gabriel N. Meloni | Jean‐François Lemineur | Frédéric Kanoufi | Patrick R. Unwin
Source: ACS electrochemistry. (article, 2024-10-07)
Field: Chemistry — Electrochemistry

<i>Operando</i> Electrochemical and Optical Characterization of the Meniscus of Scanning Electrochemical Cell Microscopy (SECCM) Probes We present a thorough description of the scanning electrochemical cell microscopy (SECCM) meniscus probe, in operation, by combining dual-channel SECCM measurements with <i>in situ</i> interference reflection microscopy (IRM). SECCM is a pipette-based nanoscale characterization tool with an unparalleled capacity for mapping the electrochemical activity of material surfaces, with high precision and at high throughput. In hopping mode, it operates by bringing the electrolyte meniscus, at the scanned pipette tip, in contact with the sample, restricting the probed area each time to a separate, newly wetted site, and forming a small-scale reactor. Each contact area can normally be imaged post-experiment, to inform on the wetted area stability and enable quantitative data interpretation (e.g., to calculate current density). However, the description of meniscus behavior during measurements would be beneficial. Herein, we utilize semi-transparent electrode substrates, to enable the direct optical observation, by IRM, of the meniscus status, with high spatial and temporal resolution, and synchronously to SECCM operation. The surface-sensitive optical method allows us to accurately capture the nature of the miniature electrochemical cell during all phases of the experiment-during approach, meniscus contact, wetting, and pipette withdrawal-and to follow subtle changes while in contact with the electrode substrate. Through the use of a dual-channel probe, we are able to monitor both the ionic current across the meniscus, between quasi-reference counter electrodes (QRCEs) under bias, and between the working electrode surface and the QRCEs. Correlating these electrochemical data and <i>operando</i> optical information via the hybrid SECCM-IRM approach aids the design of experimental protocols, streamlines the interpretation of results, and paints a comprehensive picture of meniscus wetting behavior. Meniscus ; Materials science ; Electrode ; Microscopy ; Scanning ion-conductance microscopy ; Pipette ; Wetting ; Electrolyte ; Scanning electrochemical microscopy ; Nanotechnology ; Scanning probe microscopy ; Capillary action ; Optics ; Electrochemistry ; Chemistry ; Composite material ; Scanning electron microscope ; Scanning confocal electron microscopy Electrochemical Analysis and Applications ; Force Microscopy Techniques and Applications ; Advanced Fluorescence Microscopy Techniques
Authors: Ming-Kai Wei | Ze‐Xin Zhang | Mingyan Ding | Michael C. Willis
Source: Angewandte Chemie International Edition (article, 2024-10-11)
Field: Chemistry — Organic Chemistry

Friedel–Crafts Reactivity with Sulfondiimidoyl Fluorides for the Synthesis of Heteroaryl Sulfondiimines Sulfur functional groups are ubiquitous in molecules used in the pharmaceutical and agrochemical industries, and within these collections sulfones hold a prominent position. The double aza-analogues of sulfones, sulfondiimines, offer significant potential in discovery chemistry but to date their applications have been limited by the lack of convenient synthetic routes. The existing methods mainly rely on imination of low-valent-sulfur intermediates, or the combination of pre-formed organometallic reagents and electrophilic S(VI)-functionalities. Herein, we describe a Friedel-Crafts-type reaction of sulfondiimidoyl fluorides with (hetero)aryls. This new SuFEx reactivity benefits from broad functional group tolerance, mild reaction conditions, and does not require the use of pre-formed organometallic reagents. The efficient use of unprotected indoles and pyrroles, as well as furan, thiophene and carbocyclic aromatics, further demonstrates the advantages of these reactions. We show that the reactivity of the sulfondiimidoyl fluorides can be tuned by switching the N-substituents, allowing an expansion of the range of coupling partners. The utility of the transformation is exemplified by the synthesis of the sulfondiimine analogue of the HIV-I reverse transcriptase-inhibitor L-737,126. Reactivity (psychology) ; Furan ; Chemistry ; Reagent ; Thiophene ; Electrophile ; Friedel–Crafts reaction ; Functional group ; Combinatorial chemistry ; Sulfur ; Molecule ; Organic chemistry ; Organic synthesis ; Catalysis ; Polymer Sulfur-Based Synthesis Techniques ; Synthesis and Catalytic Reactions ; Catalytic C–H Functionalization Methods
Authors: Jeroen Staal | Barış Çağlar | Véronique Michaud
Source: Composites Science and Technology (article, 2024-04-02)
Field: Chemistry — Organic Chemistry

Self-catalysed frontal polymerisation enables fast and low-energy processing of fibre reinforced polymer composites Frontal polymerisation has the potential to bring unprecedented reductions in energy demand and process time to produce fibre reinforced polymer composites. Production of epoxy-based fibre reinforced polymer parts with high fibre volume content, commonly encountered in industry, is however hindered by the heat sink created by the fibres and the mould, overcoming the heat output of the chemical reaction, thus preventing front propagation. We propose a novel self-catalysed frontal polymerisation manufacturing method based on the integration of thin resin channels in thermal contact with the composite stack as a strategy for low-energy production of high fibre volume fraction polymer composites without the need for a continuous energy input. Frontal polymerisation inside the resin channel proceeds faster and preheats the fabric stack, thus catalysing the process. Parts with up to 60% fibre content are successfully produced independently of the sample thickness. Fillers added within the resin channels provide means to tailor the frontal polymerisation process kinetics. The parts have a significantly higher glass transition temperature than those produced in a conventional oven, and comparable mechanical properties while energy consumption is reduced by over 99.5%. Materials science ; Composite material ; Polymer ; Polymerization ; Epoxy ; Stack (abstract data type) ; Composite number ; Volume fraction ; Glass fiber ; Volume (thermodynamics) Photopolymerization techniques and applications ; Additive Manufacturing and 3D Printing Technologies ; Nanofabrication and Lithography Techniques
Authors: Dipeng Li | Yirong Wang | Shan Zhu | Xuezhong Hu | Renjie Liang
Source: Frontiers in Bioengineering and Biotechnology (review, 2024-08-14)
Field: Materials Science — Biomaterials

Recombinant fibrous protein biomaterials meet skin tissue engineering Natural biomaterials, particularly fibrous proteins, are extensively utilized in skin tissue engineering. However, their application is impeded by batch-to-batch variance, limited chemical or physical versatility, and environmental concerns. Recent advancements in gene editing and fermentation technology have catalyzed the emergence of recombinant fibrous protein biomaterials, which are gaining traction in skin tissue engineering. The modular and highly customizable nature of recombinant synthesis enables precise control over biomaterial design, facilitating the incorporation of multiple functional motifs. Additionally, recombinant synthesis allows for a transition from animal-derived sources to microbial sources, thereby reducing endotoxin content and rendering recombinant fibrous protein biomaterials more amenable to scalable production and clinical use. In this review, we provide an overview of prevalent recombinant fibrous protein biomaterials (collagens, elastin, silk proteins and their chimeric derivatives) used in skin tissue engineering (STE) and compare them with their animal-derived counterparts. Furthermore, we discuss their applications in STE, along with the associated challenges and future prospects. Tissue engineering ; Recombinant DNA ; Biomaterial ; Synthetic biology ; Spider silk ; Protein engineering ; Genetically engineered ; SILK ; Nanotechnology ; Chemistry ; Biomedical engineering ; Computational biology ; Materials science ; Biology ; Biochemistry ; Engineering Silk-based biomaterials and applications ; Electrospun Nanofibers in Biomedical Applications ; Collagen: Extraction and Characterization
Authors: Conor Wynne | Robert B. P. Elmes
Source: Frontiers in Chemistry (article, 2024-07-05)
Field: Chemistry — Spectroscopy

Utilising a 1,8-naphthalimide probe for the ratiometric fluorescent visualisation of caspase-3 The development of selective and sensitive probes for monitoring caspase-3 activity-a critical enzyme involved in apoptosis-remains an area of significant interest in biomedical research. Herein, we report the synthesis and characterisation of a novel ratiometric fluorescent probe, Ac-DEVD-PABC-Naph, designed to detect caspase-3 activity. The probe utilises a 1,8-naphthalimide fluorophore covalently linked to a peptide sequence via a self-immolative <i>p</i>-aminobenzyl alcohol (PABA) linker. Upon enzymatic cleavage by caspase-3, the probe undergoes spontaneous degradation, releasing the free naphthalimide fluorophore, resulting in a ratiometric change in fluorescence emission. Spectroscopic studies revealed a time-dependent ratiometric fluorescent response, demonstrating the probe's ability to visualise caspase-3 activity with high sensitivity. Enzyme kinetics such as <i>K</i> <sub><i>m</i></sub> (Michaelis constant), <i>k</i> <sub><i>cat</i></sub> (turnover number), and <i>LOD</i> (Limit of Detection) were obtained, suggesting that the probe possesses comparable kinetic data to other probes in literature, but with the added benefits of ratiometric detection. Selectivity studies also demonstrated the probe's specificity for caspase-3 over other endogenous species and enzymes. Ac-DEVD-PABC-Naph may be a promising tool for the quantitative detection and fluorescent visualisation of caspase-3 activity in biological systems, with potential applications in apoptosis research and drug development. Fluorophore ; Fluorescence ; Chemistry ; Detection limit ; Biophysics ; Linker ; Cleavage (geology) ; Enzyme ; Caspase 3 ; Combinatorial chemistry ; Biochemistry ; Apoptosis ; Materials science ; Biology ; Chromatography Molecular Sensors and Ion Detection ; Luminescence and Fluorescent Materials ; Advanced biosensing and bioanalysis techniques
Authors: Nickolas A. Joyner | João Gabriel Farias Romeu | B. Kent | David A. Dixon
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Materials Science — Polymers and Plastics

The electronic structure of diatomic nickel oxide The nature of the Ni-O bond is relevant to catalytic and environmental applications. The vibrational frequency and electronic structure of NiO were calculated using CASSCF, icMRCI+Q, CCSD(T), and DFT. CASSCF predicted a quintet state (<sup>5</sup>Σ<sup>-</sup>) ground state for the equilibrium bond distance with a state crossing at 1.65 Å, where the triplet (<sup>3</sup>Σ<sup>-</sup>) state becomes of lower energy. These states arise from the 3d<sup>8</sup>(<sup>3</sup>F)4s<sup>2</sup> (<sup>3</sup>F) and 3d<sup>9</sup>(<sup>2</sup>D)4s<sup>1</sup> (<sup>3</sup>D) configurations of Ni. The icMRCI+Q method predicts a triplet (<sup>3</sup>Σ<sup>-</sup>) ground state and does not predict a state crossing with the quintet. This state has significant ionic character with the 2p<sub><i>z</i></sub> of O bonding with the 4s/3d<sub><i>z</i><sup>2</sup></sub> of the Ni to form a σ bond. The NiO frequency at the icMRCI+Q level of 835.0 cm<sup>-1</sup> is in excellent agreement with experiment; the value of <i>r</i><sub>e</sub> is 1.5992 Å at this computational level. CCSD(T) predicts <i>ω</i><sub>e</sub> = 888.80 cm<sup>-1</sup> when extrapolated to the complete basis set limit. Frequencies predicted using CCSD(T) deviate from experiment consistent with the calculations showing large multireference character. A wide array of density functionals were benchmarked. Of the 43 functionals tested, the ones that gave the best prediction of the frequency are ωB97XD, CAM-B3LYP, and τ-HCTH with respective values of 831.8, 838.3, and 837.4 cm<sup>-1</sup> respectively. The bond dissociation energy (BDE) of NiO is predicted to be 352.4 kJ mol<sup>-1</sup> at the Feller-Peterson-Dixon (FPD) level in good agreement with one of the experimental values. The calculated BDEs at the DFT level are sensitive to the choice of functional and atomic asymptote. Sixteen functionals predicted the BDE within 20 kJ mol<sup>-1</sup> of the FPD value. Diatomic molecule ; Non-blocking I/O ; Electronic structure ; Nickel oxide ; Nickel ; Bond length ; Materials science ; Computational chemistry ; Oxide ; Atomic physics ; Chemistry ; Molecular physics ; Catalysis ; Crystallography ; Physics ; Molecule ; Metallurgy ; Crystal structure ; Organic chemistry Transition Metal Oxide Nanomaterials