jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: George Callender | K.F. Goddard | P. L. Lewin
Source: IEEE Transactions on Dielectrics and Electrical Insulation (article, 2021-02-01)
Field: Materials Science — Materials Chemistry

Simulating Surface Charge Dynamics Surface charge dynamics can play an important role in electric field distributions in both AC and DC insulation systems. In this paper the theory behind surface charge dynamics is introduced with a particular focus on the calculation of surface divergence; an operator which is used to determine movement of charge constrained to a surface. A detailed discussion of the model implementation is provided and validated against an analytical solution. Surface charge dynamics in AC and DC insulation systems are then investigated. Assuming the measurement data in the literature is representative it is demonstrated that surface currents have the capability to significantly alter electric field distributions in voids, even over the timescales of an AC cycle. Electric field ; Charge (physics) ; Surface charge ; Surface (topology) ; Charge density ; Dynamics (music) ; Electrostatics ; Divergence (linguistics) ; Electric charge ; Mechanics ; Focus (optics) ; Field (mathematics) ; Electric potential ; Physics ; Materials science ; Computational physics ; Voltage ; Electrical engineering ; Engineering ; Optics ; Acoustics ; Mathematics High voltage insulation and dielectric phenomena ; Power Transformer Diagnostics and Insulation ; Lightning and Electromagnetic Phenomena
Authors: Theresa Hennig | Michael Kühn
Source: Advances in geosciences (article, 2021-11-09)
Field: Chemistry — Inorganic Chemistry

Uranium migration through the Swiss Opalinus Clay varies on the metre scale in response to differences of the stability constant of the aqueous, ternary uranyl complex Ca&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;UO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;(CO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;)&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; Abstract. The simulation of uranium migration through the Swiss Opalinus Clay is used as an example to quantify the influence of varying values of a stability constant in the underlying thermodynamic database on the migration lengths for the repository scale. Values for the stability constant of the neutral, ternary uranyl complex Ca2UO2(CO3)3 differ in literature by up to one order of magnitude. Within the studied geochemical system, either the neutral or the anionic complex CaUO2(CO3)32- is the predominant one, depending on the chosen value for the neutral complex. This leads to a changed interaction with the diffuse double layers (DDL) enveloping the clay minerals and thus can potentially influence the diffusive transport of uranium. Hence, two identical scenarios only differing in the value for the stability constant of the Ca2UO2(CO3)3 complex were applied in order to quantify and compare the migration lengths of uranium on the host rock scale (50 m) after a simulation time of one million years. We ran multi-component diffusion simulations for the shaly and sandy facies in the Opalinus Clay. A difference in the stability constant of 1.33 log units changes the migration lengths by 5 to 7 m for the sandy and shaly facies, respectively. The deviation is caused by the anion exclusion effect. However, with a maximum diffusion distance of 22 m, the influence of the stability constant of the Ca2UO2(CO3)3 complex on uranium migration in the Opalinus Clay is negligible on the host rock scale. Uranyl ; Uranium ; Diffusion ; Ternary operation ; Constant (computer programming) ; Mineralogy ; Chemistry ; Geology ; Thermodynamics ; Materials science ; Physics ; Metallurgy Radioactive element chemistry and processing ; Groundwater flow and contamination studies ; Geochemistry and Geologic Mapping
Authors: P.O. Gentsar | Alexander V. Stronski | Л. А. Карачевцева | V. F. Onyshchenko
Source: Physics and Chemistry of Solid State (article, 2021-08-31)
Field: Materials Science — Materials Chemistry

Optical Properties of Monocrystalline Silicon Nanowires The paper presents the results of a study of the optical reflection and transmission spectra of a silicon single crystal p-Si (100) with silicon nanowires grown on both sides and porous silicon p-Si (100) on a single crystal substrate in the spectral range 0.2 ÷ 1.7 μm. The layers of nanowires had a thickness of 5.5 µm, 20 µm, 50 µm and a porosity of 60 %. The porous silicon layers had a thickness of 5 μm, 50 μm and a porosity of 45 %, 55 % and 65 %. The change in the energy band structure in single-crystal silicon nanowires and in a single-crystal matrix of porous silicon is shown. Monocrystalline silicon ; Porous silicon ; Materials science ; Silicon ; Nanowire ; Substrate (aquarium) ; Nanocrystalline silicon ; Porosity ; Optoelectronics ; Crystal (programming language) ; Single crystal ; Crystalline silicon ; Crystallography ; Composite material ; Chemistry ; Amorphous silicon Silicon Nanostructures and Photoluminescence
Authors: V. F. Onyshchenko
Source: Journal of Nano- and Electronic Physics (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Distribution of Excess Charge Carriers in Bilateral Macroporous Silicon with Different Thicknesses of Porous Layers Journal of Nano- and Electronic Physics. Scientific journal. ISSN: 2077-6772. Journal abbreviation: J. Nano- Electron. Phys. No page charges. All articles are freely available on-line. Issued 4 times per year. Publisher: Sumy State University. (Sumy, Ukraine) Materials science ; Porous silicon ; Silicon ; Porosity ; Distribution (mathematics) ; Porous medium ; Charge (physics) ; Charge carrier ; Composite material ; Optoelectronics ; Mathematics ; Physics Silicon Nanostructures and Photoluminescence ; Silicon and Solar Cell Technologies ; Nanowire Synthesis and Applications
Authors: Andrea Canal-Martín | Claudio D. Navo | Elena Sáez | Dolores Molero | Gonzalo Jiménez‐Osés | Ruth Pérez‐Fernández
Source: Organic & Biomolecular Chemistry (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Nucleophilic catalysis of<i>p</i>-substituted aniline derivatives in acylhydrazone formation and exchange Hydrazone bond formation is a versatile reaction employed in several research fields. It is one of the most popular reversible reactions in dynamic combinatorial chemistry. Under physiological conditions, hydrazone exchange benefits from the addition of a nucleophilic catalyst. We report a mechanistic study and superior performance of electron-rich p-substituted aniline derivatives as catalysts for efficient hydrazone formation and exchange in both protic and aprotic solvents. Rigorous kinetic analyses demonstrate that imine formation with 3-hydroxy-4-nitrobenzaldehyde and aniline derivatives proceeds with unprecedented third-order kinetics in which the aldehyde consistently shows a partial order of two. Computational investigations provide insights into the mechanisms of these transformations. Chemistry ; Aniline ; Hydrazone ; Catalysis ; Nucleophile ; Combinatorial chemistry ; Nucleophilic addition ; Synergistic catalysis ; Medicinal chemistry ; Organic chemistry Chemical Reaction Mechanisms ; Chemical Synthesis and Reactions ; Synthesis and Biological Evaluation
Authors: Layla Adnan AbdulJabar | Dakhil Mutalq | Ali A. A. Al-Shawi
Source: Egyptian Journal of Chemistry (article, 2021-03-28)
Field: Chemistry — Organic Chemistry

Synthesis of novel 2-thioxo-4-imidazolidinone derivatives and evaluation of their antibacterial, and antifungal activities The infectious diseases caused by antimicrobials pathogens are difficult, harmful, and sometimes impossible to treat. Therefore, design new drugs to treat antimicrobial infections is the biggest challenge for modern medicine. 2-Thioxo-4-imidazolidinone is used for the synthesis of a wide variety of new substituted imidazolidinone derivatives. In this study, we designing eight novel compounds derived for the 2-thioxo-4-imidazolidinones (5a-h). The preparation was in two steps via Micheal addition of phenyl hydrazide (2a), 4-methyl phenyl hydrazide 2b on N-substituted maleimides 1a-d in ethanol, and the second step by reaction of maleimide derivatives with cyclohexyl isothiocyanate 4 in acetonitrile. The chemical structures of the compounds were identified using FT-IR, 1H-NMR, 13C-NMR, and mass spectra, as well as the melting point. The antibacterial and antifungal evaluation was carried out to target their activities. Compound N-(5-(2-((4-chlorophenyl)amino)-2-oxoethyl)-3-cyclohexyl-4-oxo-2-thioxoimidazolidin-1-yl) benzamide (5b) exhibited antibacterial activity toward Staphylococcus aureus and Pseudomonas aeruginosa with equal minimum inhibitory concentration (MIC) values of 25 mg/mL. Compounds N-(3-cyclohexyl-4-oxo-5-(2-oxo-2-(phenylamino)ethyl)-2-thioxoimidazolidin-1-yl) benzamide (5a), N-(5-(2-((4-chlorophenyl)amino)-2-oxoethyl)-3-cyclohexyl-4-oxo-2-thioxoimidazolidin-1-yl) benzamide (5b), N-(5-(2-((4-bromophenyl)amino)-2-oxoethyl)-3-cyclohexyl-4-oxo-2-thioxo imidazolidin-1-yl) benzamide (5c), and N-(3-cyclohexyl-4-oxo-5-(2-oxo-2-(phenylamino)ethyl)-2-thioxoimidazolidin-1-yl)-4-methyl benzamide (5e) exhibited antifungal activity toward Candida albicans, while all compounds exhibited antifungal activity toward Aspergillus niger except for compound 5h, with various MIC values. In conclusion, the results demonstrate that the new compounds have to promise as antifungal agents. Moreover, compound 5b could develop as an antibacterial agent. Antifungal ; Chemistry ; Combinatorial chemistry ; Pharmacology ; Microbiology ; Medicine ; Biology Synthesis and biological activity ; Synthesis and Characterization of Heterocyclic Compounds ; Synthesis of heterocyclic compounds
Authors: Chen-Sheng Yu | Han Wang | Li‐Jing Min | Liang Han | Jianjun Shi | Xing‐Hai Liu
Source: Chinese Journal of Organic Chemistry (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Synthesis, Cyrstal Structure and Fungicidal Activity of New Triazole Compounds Containing Trifluoromethylphenyl Moiety * ,a ( a 310014) ( b 313000 Chemistry ; Moiety ; Fungicide ; Triazole ; Stereochemistry ; Combinatorial chemistry ; Organic chemistry ; Botany Synthesis and Biological Evaluation ; Synthesis and biological activity ; Fungal Plant Pathogen Control
Authors: Tan Phuoc Ton | Trần Thị Yến Nhi | Le Hang Dang | Kim Thi Hoang Nguyen | Đoàn Đình Phương | Van Toan Nguyen | Dinh Trung Nguyen | Bao Huy Le | Ngoc Quyên Trân | Bich Tram Nguyen
Source: International Journal of Polymer Science (article, 2021-03-30)
Field: Materials Science — Biomaterials

Preparation and Characterization of Polyamidoamine G2.0-Hematin as a Biocatalyst for Fabricating Catecholic Gelatin Hydrogel In this study, we report that an enzyme-mimicking biocatalyst polyamidoamine (PAMAM) dendrimer G2.0-hematin (G2.0-He) was fabricated successfully. The chemical structure of G2.0-He was verified by 1H NMR and FT-IR spectroscopy. G2.0-He exhibited a size distribution from <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mn>11.6</a:mn> <a:mo>±</a:mo> <a:mn>1.7</a:mn> <a:mtext> </a:mtext> <a:mtext>nm</a:mtext> </a:math> to <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mn>12.5</c:mn> <c:mo>±</c:mo> <c:mn>2.9</c:mn> <c:mtext> </c:mtext> <c:mtext>nm</c:mtext> </c:math> and a zeta potential from 32.5 mV to 25.6 mV along with the enhancement of the hematin conjugation degree. The relative activity of G2.0-He was evaluated based on pyrogallol oxidation reactions at <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mtext>pH</e:mtext> <e:mo>=</e:mo> <e:mn>7</e:mn> </e:math> . The results showed that G2.0-He was more stable than horseradish peroxidase (HRP) enzyme in high H2O2 concentrations. The HRP-mimic ability of G2.0-He was also confirmed by the catalyzation when preparing catecholic gelatin hydrogels under mild conditions. Moreover, our results also revealed that these hydrogels performed with excellent cytocompatibility in an in vitro study and could be used as a potential scaffold for adhesion and proliferation of fibroblast cells. The obtained results indicated that G2.0-He is a suitable platform for altering the HRP enzyme in several biomedical applications. Gelatin ; Self-healing hydrogels ; Horseradish peroxidase ; Zeta potential ; Biocatalysis ; Click chemistry ; Nuclear chemistry ; Materials science ; Chemistry ; Enzyme ; Polymer chemistry ; Nanotechnology ; Biochemistry ; Catalysis ; Nanoparticle Electrospun Nanofibers in Biomedical Applications ; Dendrimers and Hyperbranched Polymers ; Advanced Nanomaterials in Catalysis
Authors: Meser M. Ali
Source: Novel Approaches in Cancer Study (article, 2021-10-20)
Field: Materials Science — Polymers and Plastics

Dendrimer-Based Nanomedicine (Paramagnetic Nanoparticle, Nanocombretastatin, Nanocurcumin) for Glioblastoma Multiforme Imaging and Therapy In brain tumors, delivering nanoparticles across the blood-brain tumor barrier presents a major challenge. Dual mode magnetic resonance imaging and fluorescent imaging probes have been developed where relaxation based Gd-DOTA or ParaCEST agents and a Near-Infrared (NIR) fluorescent dye, DL680 were conjugated on the surface of dendrimer. The <i>in vivo</i> and <i>ex vivo</i> imaging of the dual-modality contrast agent showed excellent potential utility for identifying the location of glioma tumors. Systemic delivery of the subsequent nano-sized agent demonstrated glioma-specific accumulation, probably due to the enhanced permeability and retention effect. The biodistribution studies revealed the G5 agents have accumulated in the glioma tumor and the liver while a G3 agent only accumulated in the brain tumor but not in the liver or kidney. Hydrophobic drug molecules like Combrestatin A4 (CA4) or curcumin have also been conjugated with dendrimers that provided high aqueous solubility with improved therapeutic effect. Biodistribution ; Glioma ; Dendrimer ; In vivo ; Conjugated system ; Curcumin ; Chemistry ; Nanomedicine ; Drug delivery ; MRI contrast agent ; Nanoparticle ; Cancer research ; Materials science ; Nanotechnology ; Medicine ; In vitro ; Biochemistry ; Polymer Dendrimers and Hyperbranched Polymers ; Nanoplatforms for cancer theranostics ; Nanoparticle-Based Drug Delivery
Authors: A. A. Ivanov | Н. Н. Белов
Source: Image Journal of Advanced Materials and Technologies (article, 2021-01-01)
Field: Materials Science — Polymers and Plastics

Fluorinated polymers: evaluation and characterization of structure and composition The proposed review represents the systematic analysis of modern methods and approaches for the characterization and structural evaluation of fluorinated polymers that have found a wide application as materials for chemical processing, chemically resistant components and coatings, pharmaceutical and electrical packaging, biomedical equipment, etc. The chemical composition of the polymers (fluorine content, its distribution inside the fluorinated materials, chemical bonds, presence of oxygen-containing groups) substantially influences on the operation properties (chemical resistance, adhesive, cohesive, optical, dielectrical, thermal, barrier, gas permeation) of the final polymeric products. Hence, it was of particularly importanсe to bond the emergence of specific features with the presence of fluorine in the chemical structure of polymer by means of related analytical techniques. Namely, we focused on spectral (IR, UV-VIS, NMR, XPS, EPR), chemical (elemental analysis), Secondary-ion mass spectroscopic (SIMS) and microscopic (AFM, SEM-EDX) methods emphasizing their general consideration and limitations as well as application for the in-depth characterization. Characterization (materials science) ; Polymer ; X-ray photoelectron spectroscopy ; Materials science ; Chemical structure ; Elemental analysis ; Chemical bond ; Fluorine ; Chemical composition ; Secondary ion mass spectrometry ; Chemical engineering ; Adhesive ; Chemical resistance ; Permeation ; Mass spectrometry ; Polymer chemistry ; Nanotechnology ; Chemistry ; Organic chemistry ; Composite material ; Chromatography ; Membrane Polymer Nanocomposite Synthesis and Irradiation ; Fiber-reinforced polymer composites ; Silicone and Siloxane Chemistry
Authors: Anna Lidskog | Sami Dawaigher | Carlos Solano Arribas | Anna Ryberg | Jacob Jensen | Karl Erik Bergquist | Anders Sundin | Per‐Ola Norrby | Kenneth Wärnmark
Source: Chemistry - A European Journal (article, 2021-04-28)
Field: Chemistry — Spectroscopy

Experimental and Computational Models for Side Chain Discrimination in Peptide–Protein Interactions A bis(18-crown-6) Tröger's base receptor and 4-substituted hepta-1,7-diyl bisammonium salt ligands have been used as a model system to study the interactions between non-polar side chains of peptides and an aromatic cavity of a protein. NMR titrations and NOESY/ROESY NMR spectroscopy were used to analyze the discrimination of the ligands by the receptor based on the substituent of the ligand, both quantitatively (free binding energies) and qualitatively (conformations). The analysis showed that an all-anti conformation of the heptane chain was preferred for most of the ligands, both free and when bound to the receptor, and that for all of the receptor-ligand complexes, the substituent was located inside or partly inside of the aromatic cavity of the receptor. We estimated the free binding energy of a methyl- and a phenyl group to an aromatic cavity, via CH-π, and combined aromatic CH-π and π-π interactions to be -1.7 and -3.3 kJ mol<sup>-1</sup> , respectively. The experimental results were used to assess the accuracy of different computational methods, including molecular mechanics (MM) and density functional theory (DFT) methods, showing that MM was superior. Substituent ; Chemistry ; Side chain ; Ligand (biochemistry) ; Two-dimensional nuclear magnetic resonance spectroscopy ; Stereochemistry ; Titration ; Density functional theory ; Molecular recognition ; Proton NMR ; Aromaticity ; Receptor ; Crystallography ; Computational chemistry ; Molecule ; Physical chemistry ; Organic chemistry ; Polymer Molecular spectroscopy and chirality ; Computational Drug Discovery Methods ; Protein Structure and Dynamics
Authors: Ethan F. Bull-Vulpe | Marc Riera | Andreas Goetz | Francesco Paesani
Source:  (preprint, 2021-07-13)
Field: Materials Science — Materials Chemistry

MB-Fit: Software Infrastructure for Data-Driven Many-Body Potential Energy Functions Many-body potential energy functions (MB-PEFs), which integrate data-driven representations of many-body short-range quantum mechanical interactions with physics-based representations of many-body polarization and long-range interactions, have recently been shown to provide high accuracy in the description of molecular interactions, from the gas to the condensed phase. Here, we present MB-Fit, a software infrastructure for the auto- mated development of MB-PEFs for generic molecules within the TTM-nrg (“Thole-type model energy”) and MB-nrg (“many-body energy”) theoretical frameworks. Besides providing all the necessary computational tools for generating TTM-nrg and MB-nrg PEFs, MB-Fit provides a seamless interface with the MBX software, a many-body energy/force calculator for computer simulations. Given the demonstrated accuracy of the MB-PEFs, we believe that MB-Fit will enable routine, predictive computer simulations of generic (small) molecules in the gas, liquid, and solid phases, including, but not limited to, the modeling of isomeric equilibria in molecular clusters, solvation processes, molecular crystals, and phase diagrams. Software ; Range (aeronautics) ; Calculator ; Computer science ; Potential energy ; Solvation ; Statistical physics ; Energy (signal processing) ; Interface (matter) ; Physics ; Computational science ; Molecule ; Materials science ; Classical mechanics ; Quantum mechanics Machine Learning in Materials Science ; Phase Equilibria and Thermodynamics ; Catalysis and Oxidation Reactions
Authors: Ziyang Wang | Yegang Lü
Source: Journal of Alloys and Compounds (article, 2021-01-13)
Field: Materials Science — Materials Chemistry

Thermal stability improvement of Sb-Si3N4 composite phase-change film by tunning crystallization mechanism Materials science ; Crystallization ; Thermal stability ; Amorphous solid ; Crystallite ; Von Neumann architecture ; Composite number ; Melting point ; Microstructure ; Grain size ; Nanotechnology ; Chemical engineering ; Composite material ; Computer science ; Metallurgy ; Crystallography ; Chemistry Phase-change materials and chalcogenides ; Advanced Memory and Neural Computing ; Transition Metal Oxide Nanomaterials
Authors: Ali Omar Turky | Miral A. Abdelmoaz | Mahmoud M. Hessien | Mohd Ali Hassan | Mikhaël Bechelany | Emad M.M. Ewais | M. M. Rashad
Source: Materials (article, 2021-08-31)
Field: Materials Science — Materials Chemistry

A Robust and Highly Precise Alternative against the Proliferation of Intestinal Carcinoma and Human Hepatocellular Carcinoma Cells Based on Lanthanum Strontium Manganite Nanoparticles In this report, lanthanum strontium manganite at different Sr<sup>2+</sup> ion concentrations, as well as Gd<sup>3+</sup> or Sm<sup>3+</sup> ion substituted La<sub>0.5-<i>Y</i></sub>M<i><sub>Y</sub></i>Sr<sub>0.5</sub>MnO<sub>3</sub> (M = Gd and Sm, <i>y</i> = 0.2), have been purposefully tailored using a sol gel auto-combustion approach. XRD profiles confirmed the formation of a monoclinic perovskite phase. FE-SEM analysis displayed a spherical-like structure of the La<sub>0.8</sub>Sr<sub>0.2</sub>MnO<sub>3</sub> and La<sub>0.3</sub>Gd<sub>0.2</sub>Sr<sub>0.2</sub>MnO<sub>3</sub> samples. The particle size of the LSM samples was found to decrease with increased Sr<sup>2+</sup> ion concentration. For the first time, different LSM concentrations were inspected for their cytotoxic activity against CACO-2 (intestinal carcinoma cells) and HepG-2 (human hepatocellular carcinoma cells). The cell viability for CACO-2 and HepG-2 was assayed and seen to decrease depending on the Sr<sup>2+</sup> ion concentration. Half maximal inhibitory concentration IC<sub>50</sub> of CACO-2 cell and HepG-2 cell inhibition was connected with Sr<sup>2+</sup> ion ratio. Low IC<sub>50</sub> was noticable at low Sr<sup>2+</sup> ion content. Such results were correlated to the particle size and the morphology. Indeed, the IC<sub>50</sub> of CACO-2 cell inhibition by LSM at a strontium content of 0.2 was 5.63 ± 0.42 µg/mL, and the value increased with increased Sr<sup>2+</sup> ion concentration by up to 0.8 to be = 25 ± 2.7 µg/mL. Meanwhile, the IC<sub>50</sub> of HepG-2 cell inhibition by LSM at a strontium content of 0.2 was 6.73 ± 0.4 µg/mL, and the value increased with increased Sr<sup>2+</sup> ion concentration by up to 0.8 to be 31± 3.1 µg/mL. All LSM samples at different conditions were tested as antimicrobial agents towards fungi, Gram positive bacteria, and Gram negative bacteria. For instance, all LSM samples were found to be active towards Gram negative bacteria Escherichia coli, whereas some samples have presumed antimicrobial effect towards Gram negative bacteria Proteus vulgaris. Such results confirmed that LSM samples possessed cytotoxicity against CACO-2 and HepG-2 cells, and they could be considered to play a substantial role in pharmaceutical and therapeutic applications. Chemistry ; Strontium ; IC50 ; Nuclear chemistry ; Analytical Chemistry (journal) ; Chromatography ; Biochemistry ; In vitro ; Organic chemistry Layered Double Hydroxides Synthesis and Applications ; Magnesium Oxide Properties and Applications ; Nanoparticle-Based Drug Delivery