jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sanguansak Sriphal | Audchara Saenkham | Tawatchai Chaodongbung | Banchob Wanno | Chatthai Kaewtong | Datchanee Pattavarakorn
Source: Research Square (preprint, 2022-02-01)
Field: Materials Science — Materials Chemistry

Reversible Coloring/Decoloring Reactions of Thermochromic Leuco Dyes Controlled by a Macrocyclic Compound Developer Abstract In this study, we examine macrocyclic compounds to determine whether they can provide a safer replacement and stable complex for BPA in thermochromic dyes. To achieve this objective, a series of macrocyclic compounds, Methyl- N -benzylhexahomo-triazacalix[3]arene ( MeAC3 ), p -Chloro- N -benzylhexahomo-triazacalix[3]arene ( ClAC3 ), α-Cyclodexdrin ( a-CD ), β-Cyclodexdrin ( β-CD ). p -tert-Butylthiacalix[4]arene ( TC4 ), Calix[4]arene ( C4 ) and Resorcin[4]arene ( RC4 ) were synthesized. Among these macrocyclic compounds, RC4 was determined to be the most appropriate candidate to replace BPA as the developer material used in thermochromic dyes. In tests of prepared thermochromic dyes, RC4 had results similar to those of BPA, achieving the best protonation/deprotonation equilibria and providing a dark contrast with the thermochromic dye. DFT calculations also showed stable complexes between RC4 and CVL via hydrogen-bond interactions. Thermochromism ; Deprotonation ; Chemistry ; Protonation ; Sasa ; Hydrogen bond ; Photochemistry ; Polymer chemistry ; Organic chemistry ; Molecule Photochromic and Fluorescence Chemistry ; Dyeing and Modifying Textile Fibers ; Photopolymerization techniques and applications
Authors: Yasunori Minami | Nao Matsuyama | Yasuo Takeichi | Ryota Watanabe | Siby Mathew | Yumiko Nakajima
Source: Research Square (preprint, 2022-07-01)
Field: Chemistry — Organic Chemistry

Depolymerization of robust polyetheretherketone to regenerate monomer units using sulfur reagents Abstract Super engineering plastics, high-performance thermoplastic resins such as polyetheretherketone (PEEK), and polyphenylene sulfide (PPS) have been utilized in industries, owing to their high thermal stability and mechanical strength. However, their robustness hinders their depolymerization to produce monomers and low-weight molecules. Presently, chemical recycling for most super engineering plastics remains relatively unexplored. Herein, we report the depolymerization of insoluble PEEK using sulfur nucleophiles via carbon–oxygen bond cleavages to form benzophenone dithiolate and hydroquinone. Treatment with organic halides converted only the former products to afford various dithiofunctionalized benzophenones. The depolymerization proceeded as a solid–liquid reaction in the initial phase. Therefore, this method was not affected by the shape of PEEK, e.g., pellets or films. Moreover, this depolymerization method was applicable to carbon- or glass fiber-enforced PEEK material. The depolymerized product, dithiofunctionalized benzophenones, could be converted into diiodobenzophenone which is an active form of aromatic substitution reactions. Depolymerization ; Monomer ; Reagent ; Sulfur ; Chemistry ; Polymer chemistry ; Polymer science ; Organic chemistry ; Polymer Chemical Synthesis and Reactions ; Carbon dioxide utilization in catalysis ; Synthesis and properties of polymers
Authors: Ian Baker
Source: Frontiers in Metals and Alloys (article, 2022-05-03)
Field: Materials Science — Materials Chemistry

Grand Challenges in Metals and Alloys FIELD GRAND CHALLENGE article Front. Met. Alloy, 03 May 2022 https://doi.org/10.3389/ftmal.2022.894403 Front (military) ; Field (mathematics) ; Metallurgy ; Political science ; Materials science ; Engineering ; Mechanical engineering ; Mathematics Machine Learning in Materials Science ; Titanium Alloys Microstructure and Properties ; Advanced Materials Characterization Techniques
Authors: Д. А. Агарков | М. А. Борик | G. M. Korableva | A. V. Kulebyakin | Е. Е. Ломонова | Filipp Milovich | В. А. Мызина | П. А. Попов | N. Yu. Tabachkova
Source: Izvestiya Vysshikh Uchebnykh Zavedenii Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering (article, 2022-07-21)
Field: Materials Science — Ceramics and Composites

Thermal conductivity of single crystals zirconia stabilized by scandium, yttrium, gadolinium, and ytterbium oxides The phase composition and heat conductivity of (ZrO 2 ) 0.9 ( R 2 O 3 ) 0.1 solid solution single crystals have been studied, where R = (Gd, Yb, Sc, Y), (ZrO 2 ) 0.9 (Sc 2 O 3 ) 0.09 (Gd 2 O 3 ) 0.01 and (ZrO 2 ) 0.9 (Sc 2 O 3 ) 0.09 (Yb 2 O 3 ) 0.01 . Single crystals have been grown by directional melt crystallization in a cold skull. The phase composition of the crystals has been studied using X-ray diffraction and Raman spectroscopy. The heat conductivity of the crystals has been studied using the absolute steady-state technique of longitudinal heat flow in the 50—300 K range. We show that at a total stabilizing oxide concentration of 10 mol.% the phase composition of the crystals depends on the ionic radius of the stabilizing cation. The (ZrO 2 ) 0.9 (Sc 2 O 3 ) 0.1 crystals have the lowest heat conductivity in the 50—300 K range while the (ZrO 2 ) 0.9 (Gd 2 O 3 ) 0.1 solid solutions have the lowest heat conductivity at 300 K.Analysis of the experimental data suggests that the heat conductivity of the crystals depends mainly on the phase composition and ionic radius of the stabilizing cation. Phonon scattering caused by the difference in the weight of the co-doping oxide cation has a smaller effect on the heat conductivity. Analytical Chemistry (journal) ; Yttrium ; Materials science ; Ytterbium ; Ionic radius ; Thermal conductivity ; Scandium ; Conductivity ; Ionic conductivity ; Crystallization ; Lutetium ; Raman spectroscopy ; Oxide ; Doping ; Ion ; Chemistry ; Physical chemistry ; Electrolyte ; Optics Advanced ceramic materials synthesis ; Nuclear materials and radiation effects ; Glass properties and applications
Authors: Tek Narsingh Malla | Kara A. Zielinski | Luis Aldama | S. Bajt | Denisse Feliz | Brendon Hayes | Mark S. Hunter | Christopher Kupitz | Stella Lisova | J. Knoška | José M. Martín-García | Valerio Mariani | Suraj Pandey | Ishwor Poudyal | Raymond G. Sierra | A. Tolstikova | Oleksandr Yefanov | Chung Hong Yoon | A. Ourmazd | Petra Fromme | Peter Schwander | Anton Barty | Henry N. Chapman | Emina A. Stojković | Alex Batyuk | Sébastien Boutet | G.N. Phillips | Lois Pollack | Marius Schmidt
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2022-12-06)
Field: Materials Science — Materials Chemistry

Heterogeneity in the <i>M. tuberculosis</i> β-lactamase inhibition by Sulbactam Abstract For decades, researchers have been determined to elucidate essential enzymatic functions on the atomic lengths scale by tracing atomic positions in real time. Our work builds on new possibilities unleashed by mix-and-inject serial crystallography (MISC) 1-5 at X-ray free electron laser facilities. In this approach, enzymatic reactions are triggered by mixing substrate or ligand solutions with enzyme microcrystals 6 . Here, we report in atomic detail and with millisecond time-resolution how the Mycobacterium tuberculosis enzyme BlaC is inhibited by sulbactam (SUB). Our results reveal ligand binding heterogeneity, ligand gating 7-9 , cooperativity, induced fit 10,11 and conformational selection 11-13 all from the same set of MISC data, detailing how SUB approaches the catalytic clefts and binds to the enzyme non-covalently before reacting to a trans- enamine. This was made possible in part by the application of the singular value decomposition 14 to the MISC data using a newly developed program that remains functional even if unit cell parameters change during the reaction. Chemistry ; Ligand (biochemistry) ; Cooperativity ; Sulbactam ; Enzyme ; Substrate (aquarium) ; Stereochemistry ; Crystallography ; Combinatorial chemistry ; Biochemistry ; Biology Enzyme Structure and Function ; Biochemical and Molecular Research ; Protein Structure and Dynamics
Authors: Kiran Vaddi | Huat Thart Chiang | Lilo D. Pozzo
Source: ChemRxiv (preprint, 2022-03-30)
Field: Materials Science — Materials Chemistry

Autonomous retrosynthesis of nanoscale structures via spectral shape matching Synthesizing complex nanostructures and assemblies in experiments involves careful tuning of design factors to obtain a suitable set of reaction conditions. In this paper, we study the application of Bayesian optimization (BO) to achieve autonomous retrosynthesis of a specific nanoparticle or nano-assembly structure, shape, and size starting from a set of reagents selected a priori. We formulate the BO as a shape matching problem given target spectra as a structural proxy with a goal to minimize the shape discrepancy. The proposed framework is grounded in analyzing the spectra as belonging to function spaces and a Riemannian metric defined on them. The metric decomposes spectral similarity into amplitude and phase components and provides a near convex function to optimize as opposed to nearly flat functions produced from the commonly used mean squared error (MSE). Applying the framework to both experimental and simulated spectra, we demonstrate the advantage of shape matching over MSE and other generic functional distance measures. Metric (unit) ; Matching (statistics) ; Set (abstract data type) ; Function (biology) ; Algorithm ; Mathematics ; Computer science ; Mean squared error ; Mathematical optimization ; Engineering ; Statistics Machine Learning in Materials Science ; Electron and X-Ray Spectroscopy Techniques ; X-ray Diffraction in Crystallography
Authors: Nicholas J. Browning | Felix A. Faber | O. Anatole von Lilienfeld
Source: The Journal of Chemical Physics (preprint, 2022-11-14)
Field: Materials Science — Materials Chemistry

GPU-accelerated approximate kernel method for quantum machine learning We introduce Quantum Machine Learning (QML)-Lightning, a PyTorch package containing graphics processing unit (GPU)-accelerated approximate kernel models, which can yield trained models within seconds. QML-Lightning includes a cost-efficient GPU implementation of FCHL19, which together can provide energy and force predictions with competitive accuracy on a microsecond per atom timescale. Using modern GPU hardware, we report learning curves of energies and forces as well as timings as numerical evidence for select legacy benchmarks from atomistic simulation including QM9, MD-17, and 3BPA. Kernel (algebra) ; Computer science ; Computational science ; Lightning (connector) ; Set (abstract data type) ; Energy (signal processing) ; Microsecond ; Quantum ; Algorithm ; Parallel computing ; Artificial intelligence ; Computer engineering ; Mathematics ; Power (physics) ; Physics ; Optics ; Quantum mechanics ; Discrete mathematics Machine Learning in Materials Science ; Nuclear Physics and Applications ; Mass Spectrometry Techniques and Applications
Authors: Attila Hunyadi | Orinamhe Godwin Agbadua | G. De Takats | György Tibor Balogh
Source: ChemRxiv (preprint, 2022-07-08)
Field: Chemistry — Organic Chemistry

Scavengome of an Antioxidant The term ‘scavengome’ refers to the chemical space of all the metabolites that may be formed from an antioxidant upon scavenging reactive oxygen or nitrogen species (ROS/RNS). This chemical space is very rich in structures representing an increased chemical complexity as compared to the parent antioxidant: a wide range of unusual heterocyclic structures, new C-C bonds, etc. may be formed. Further, in a biological environment, this increased chemical complexity is directly translated from the localized conditions of oxidative stress that determines the amounts and types of ROS/RNS present. Biomimetic oxidative chemistry provides an excellent tool to model chemical reactions between antioxidants and ROS/RNS. In this chapter, we provide an overview on the known metabolites obtained by biomimetic oxidation of a few selected natural antioxidants, i.e., a stilbene (resveratrol), a pair of hydroxycinnamates (caffeic acid and methyl caffeate), and a flavonol (quercetin), and discuss the drug discovery perspectives of the related chemical space. Antioxidant ; Chemistry ; Chemical space ; Resveratrol ; Reactive oxygen species ; Quercetin ; Oxidative stress ; Caffeic acid ; Chemical structure ; Biochemistry ; Organic chemistry ; Drug discovery ; Combinatorial chemistry Free Radicals and Antioxidants ; Bioactive Compounds and Antitumor Agents ; Radical Photochemical Reactions
Authors: Asmaa Ahmed Hatem Sultan
Source: International Journal of Health Sciences (article, 2022-09-18)
Field: Materials Science — Materials Chemistry

effectiveness of nano-cobalt oxide with manufactured plant extract and its properties on inhibiting the growth of some types of bacteria and fungi isolated from skin infections The prepared cobalt oxide nanoparticles were manufactured in the first and second methods, and they show the properties of the nanomaterials for all solutions of plant extracts. XRD examination showed (440) 65, (622) 79, while Sem's examination showed the appearance with a size of 10-25 nm. Tem examination gave that nanoparticles with a size not exceeding 0.5-60 nm. The UV absorbance and permeability test indicated that the nanomaterial is at a value between 236-800nm, and energy gap values of 2.0-3.8 ev. Ft-ir assay shows that the bonding sites for cobalt oxide are at (±50) (505 to 694), and the Zeta Potential test indicated that all the particles of the solutions have very small values and that the material is not agglomerating. The Aleo vera plant extract with cobalt oxide nanomaterial, where the diameters of the inhibition zones were (35, 35, 45) mm, respectively, for the growth of both Ps.aeruginosa, S. aureus and E.coli bacteria. The results of the effect of cobalt oxide solutions on the inhibition of the growth of fungi were great, and that the nanomaterial was also sweeping, showing the absence of fungal growth Trichophyton mentagrophytes. Nanomaterials ; Zeta potential ; Absorbance ; Cobalt ; Cobalt oxide ; Nuclear chemistry ; Nanoparticle ; Chemistry ; Bacteria ; Oxide ; Bacterial growth ; Materials science ; Chemical engineering ; Nanotechnology ; Organic chemistry ; Chromatography ; Biology Nanoparticles: synthesis and applications ; Medical and Biological Ozone Research
Authors: Zijun Xu | Yuying Liu | Jiao Chen | Xiyuan Wang | Hao Liu | Qingdong Shi | Jianjie Wei
Source: Research Square (preprint, 2022-01-11)
Field: Materials Science — Materials Chemistry

pH-Regulated Carbon Dots Fluorescence Sensor Array Detection of Multiple Heavy Metal Ions Under Stepwise Prediction Fluorescence ; Metal ions in aqueous solution ; Heavy ion ; Ion ; Metal ; Carbon fibers ; Materials science ; Chemistry ; Nanotechnology ; Analytical Chemistry (journal) ; Environmental chemistry ; Physics ; Optics ; Metallurgy ; Organic chemistry Carbon and Quantum Dots Applications ; Advanced biosensing and bioanalysis techniques ; Electrochemical sensors and biosensors
Authors: Subin Sahu | Nathanael S. Schwindt | Benjamin J. Coscia | Michael R. Shirts
Source: ChemRxiv (preprint, 2022-09-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Obtaining and characterizing stable bicontinuous cubic morphologies and their nanochannels in lyotropic liquid crystal membranes Amphiphilic monomers in polar solvents can self-assemble into lyotropic liquid crystal (LLC) bicontinuous cubic structures under the right composition and temperature conditions. After cross-linking, the resulting polymer membranes with 3D continuous uniform channels are excellent candidates for filtration applications. Designing such membranes with desired physical and chemical properties requires molecular level understanding of the structure, which can be obtained through molecular modeling. However, building molecular models of bicontinuous cubic structures is challenging due to their narrow regime of stability and the difficulty of self-assembly of large unit cells in molecular simulations. We developed a protocol for building stable bicontinuous cubic unit cells involving both parameterization and assembly of the components. We validated theoretical structure against experimental results for one such LLC monomer and provide insight into the structure missing in experimental data, as well as demonstrate the qualitative nature of water and solute transport through these membranes. Lyotropic liquid crystal ; Membrane ; Monomer ; Lyotropic ; Materials science ; Polymer ; Chemical physics ; Chemical engineering ; Amphiphile ; Liquid crystal ; Molecular dynamics ; Self-assembly ; Nanotechnology ; Copolymer ; Chemistry ; Computational chemistry ; Liquid crystalline ; Composite material Liquid Crystal Research Advancements ; Lipid Membrane Structure and Behavior ; Block Copolymer Self-Assembly
Authors: A. P Guerra | D. T Raspe | A. C. S Rosa | C. Silva
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2022-11-15)
Field: Chemistry — Organic Chemistry

Síntese de ácidos graxos livres do óleo de caroço de algodão R E S U M O<br> Vislumbrando obter um hidrolisado com elevados percentuais de ácidos graxos livres (AGLs), o presente trabalho teve como objetivo explorar a hidrólise enzimática do óleo de caroço de algodão (OCA). Diferentes pré-tratamentos para purificação do óleo foram propostos, dos quais a lavagem com água aquecida à 80 ºC resultou em apreciáveis 52,2% de AGLs, sendo esta etapa fixada para a condução das posteriores. O efeito das variáveis do processo (percentual de água, pH da solução tampão e percentual de catalisador) foi avaliado sequencialmente, por meio dos catalisadores enzimáticos Lipozyme® RM IM e Lipozyme® TL IM. O aumento do percentual de água (5-100% em relação à massa de óleo) e pH da solução tampão (5,7-8,2) no meio reacional foi proporcional ao aumento da formação de AGL para ambas as enzimas avaliadas, com destaque para a Lipozyme® TL IM. Ao analisar a influência do catalisador (1-15%), pode-se constatar que menores percentuais (5%) promoveram a formação de maiores teores de AGLs (~83%). Após efeito das variáveis, na faixa experimental considerada, ~83% de AGLs foram obtidos utilizando 50% de solução tampão à pH 8,2 e 5% de enzima Lipozyme® TL IM, durante 6 horas de reação à 55 ºC e 400 rpm.<br> Palavras-Chaves: Catálise enzimática, Hidrólise, Variáveis experimentais. Chemistry Edible Oils Quality and Analysis
Authors: Nicolas Castel | François‐Xavier Coudert
Source: ChemRxiv (preprint, 2022-09-05)
Field: Chemistry — Inorganic Chemistry

Challenges in Molecular Dynamics of Amorphous ZIFs using Reactive Force Fields While amorphous metal–organic frameworks (a-MOFs) form an emerging class of materials of growing interest, their structural characterization remains experimentally and computationally challenging challenging. Out of the many molecular simulation methods that exist to model these disordered materials, one strategy consists in simulating the phase transition from a crystalline MOF to the amorphous state using molecular dynamics. ReaxFF reactive force fields have been proposed for this purpose in several studies to generate models of zeolitic imidazolate frameworks (ZIFs) glasses by melt-quenching. In this work, we investigate in detail the accuracy and reliability of this approach by reproducing the published procedures and comparing the structure of the resulting glasses to other data, including ab initio modeling. We find that the in silico melt-quench procedure is extremely sensitive to the choice of methodology and parameters, and suggest adaptations to improve the scheme. We also show that the glass models generated with ReaxFF are markedly different from their ab initio counterparts, as well as known experimental characteristics, and feature an unphysical description of the local coordination environment, which in term affects the medium-range and bulk properties. ReaxFF ; Molecular dynamics ; Amorphous solid ; Zeolitic imidazolate framework ; Force field (fiction) ; Materials science ; Ab initio ; Chemical physics ; Quenching (fluorescence) ; Glass transition ; Statistical physics ; Nanotechnology ; Computational chemistry ; Computer science ; Chemistry ; Physics ; Interatomic potential ; Polymer ; Physical chemistry ; Metal-organic framework ; Crystallography Metal-Organic Frameworks: Synthesis and Applications ; Lanthanide and Transition Metal Complexes ; Magnetism in coordination complexes
Authors: Zhen Chen | Lei Xu
Source: Research Square (preprint, 2022-03-08)
Field: Materials Science — Materials Chemistry

Obtaining A Unified Picture of Heterogeneous and Homogeneous Crystallization with Kinetic Transition Rate Abstract Heterogeneous and homogeneous crystallization exhibit distinct phase transition kinetics. However, due to the difficulty of realizing both heterogeneous and homogeneous crystallization under an identical thermodynamic condition, an independent comparison of the two remains lacking. In this work, we experimentally realize a continuous tuning from heterogeneous to homogeneous crystallization under an identical thermodynamic condition, capture the entire colloidal crystallization process of each particle, and discover a universal picture of the two modes. In the heterogeneous crystallization regime, we reveal an unexpected variation of critical nucleus size with boundary disorderness instead of contact angle, which violates the classical nucleation theory but enables the system tuning. Moreover, analogous to reaction rates in chemical reactions, we propose and measure the kinetic transition rates of crystallization, which quantify the transition probabilities between any two intermediate structures. To our surprise, regardless of heterogeneous or homogeneous crystallization, all 42 kinetic transition rates fall onto universal master curves, which unifies the two distinct crystallization modes into a universal picture. Homogeneous ; Kinetic energy ; Crystallization ; Transition (genetics) ; Materials science ; Thermodynamics ; Statistical physics ; Chemistry ; Physics ; Classical mechanics Crystallization and Solubility Studies ; nanoparticles nucleation surface interactions ; Material Dynamics and Properties
Authors: Wenke Li | Kai Li | Xiujian Zhao | Chao Liu | François‐Xavier Coudert
Source: ChemRxiv (preprint, 2022-03-21)
Field: Materials Science — Materials Chemistry

The defective nature of CdSe quantum dots embedded in inorganic matrices Quantum dots (QDs) embedded in inorganic matrices have been extensively studied for their potential applications in lighting, displays, and solar cells. While a significant amount of research focused on its experimental fabrication, the origin of their relatively low photoluminescence quantum yield has not been investigated yet, although it severely hinders practical applications. In this work, we use time-dependent density functional theory (TDDFT) to pinpoint the nature of excited states of CdSe quantum dots embedded in various inorganic matrices. The formation of undercoordinated Se atoms and non-bridging oxygen atoms at QD/glass interface is responsible for the localization of a hole wavefunction, leading to the formation of low- energy excited states with weak oscillator strength. These states provide pathways for non-radiative processes and compete with radiative emission. The photoluminescence performance is predicted for CdSe quantum dots in different matrices, and validated by experiments. The results of this work have significant implications for understanding the underlying photophysics of CdSe quantum dots embedded in inorganic matrices that would facilitate the fabrication of highly luminescent glasses. Quantum dot ; Photoluminescence ; Excited state ; Time-dependent density functional theory ; Density functional theory ; Materials science ; Quantum yield ; Radiative transfer ; Nanotechnology ; Fabrication ; Oscillator strength ; Wave function ; Chemical physics ; Optoelectronics ; Chemistry ; Physics ; Atomic physics ; Computational chemistry ; Quantum mechanics ; Spectral line Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Luminescence Properties of Advanced Materials