jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Kourosh Razmgar | Mohammednoor Altarawneh | Ibukun Oluwoye | Nuseiba Altarawneh | Gamini Senanayake
Source: Journal of Molecular Structure (article, 2022-06-01)
Field: Materials Science — Materials Chemistry

Thermodynamic stability of niobium-doped ceria surfaces Niobium ; Chemistry ; Catalysis ; Niobium oxide ; Oxide ; Doping ; Lattice constant ; Metal ; Gibbs free energy ; Lattice (music) ; Inorganic chemistry ; Physical chemistry ; Chemical physics ; Diffraction ; Thermodynamics ; Materials science Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions ; Copper-based nanomaterials and applications
Authors: Shuchang Luo | Hongjing An | Bangzhi Lou | Bing Zeng | Hong Liu
Source: Polyhedron (article, 2022-06-17)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Effect of para substituents on magnetic properties of azido-Cu(II) complexes with benzoate/azide coligands: A theoretical perspective Chemistry ; Superexchange ; Substituent ; Mulliken population analysis ; Azide ; Antiferromagnetism ; Atomic orbital ; Carboxylate ; Inductive coupling ; Crystallography ; Magnetic moment ; Density functional theory ; Population ; Computational chemistry ; Stereochemistry ; Condensed matter physics ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Metal-Catalyzed Oxygenation Mechanisms
Authors: Corey E. Frank | Emma E. McCabe | Fabio Orlandi | Pascal Manuel | Xiaoyan Tan | Zheng Deng | Changqing Jin | Mark Croft | Thomas J. Emge | Shukai Yu | Huaiyu Wang | Venkatraman Gopalan | Saul H. Lapidus | Meixia Wu | Man‐Rong Li | Juliane Groß | P. V. Burger | Aleksandra Mielewczyk‐Gryń | Tomasz Klimczuk | Weiwei Xie | David Walker | M. Greenblatt
Source: Chemistry of Materials (article, 2022-06-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Fe<sub>3–<i>x</i></sub>InSn<sub><i>x</i></sub>O<sub>6</sub> (<i>x</i> = 0, 0.25, or 0.5): A Family of Corundum Derivatives with Sn-Induced Polarization and Above Room Temperature Antiferromagnetic Ordering Three new double corundum derivative compounds, Fe3–xInSnxO6 (x = 0. 0.25, or 0.5), were synthesized at high pressure and temperature (6 GPa and 1400–1450 °C). All of the compounds order antiferromagnetically well above room temperature (TN = 608, 532, and 432 K for x = 0, 0.25, and 0.5, respectively). The x = 0 phase crystallizes as centrosymmetric R3̅c, but the inclusion of closed-shell d10 Sn4+ induces x = 0.25 and 0.5 to crystallize as noncentrosymmetric R3c. Microprobe measurements indicate that for x = 0.25 and 0.5, the substitution of Sn4+ is not offset by vacancies, which implies the presence of Fe2+, as corroborated by X-ray absorption near-edge spectroscopy and single-crystal X-ray structure refinements. Neutron powder diffraction experiments on x = 0.5 indicate that these compounds are canted A-type antiferromagnets that, like Fe2O3 and InFeO3, consist of ferromagnetic layers that stack antiferromagnetically with a single magnetic transition. Weak ferromagnetic interactions persist to very high temperatures. Temperature-dependent second harmonic generation (SHG) measurements on x = 0.25 and 0.5 show a SHG response with ferroelectric-like hysteretic maxima that correspond with the respective magnetic transitions, which suggest coupling of the magnetic and polarization order. These new compounds provide more information about fine-tuning the electronic, magnetic, and structural properties of corundum-derived mutlferroics in the search for tunable high-temperature magnetoelectric materials. Corundum ; Crystallography ; Ferromagnetism ; Ferroelectricity ; Materials science ; Magnetic moment ; Single crystal ; Crystal structure ; Mössbauer spectroscopy ; Condensed matter physics ; Chemistry ; Analytical Chemistry (journal) ; Mineralogy Multiferroics and related materials ; Advanced Condensed Matter Physics ; Magnetic and transport properties of perovskites and related materials
Authors: Caitlin R. McGranahan | David F. Watson
Source: The Journal of Chemical Physics (article, 2022-01-13)
Field: Materials Science — Materials Chemistry

Influence of donor-to-acceptor ratio on excited-state electron transfer within covalently tethered CdSe/CdTe quantum dot colloidal heterostructures Carbodiimide-mediated coupling chemistry was used to synthesize heterostructures of CdSe and CdTe quantum dots (QDs) with varying ratios of electron-donating CdTe QDs and electron-accepting CdSe QDs. Heterostructures were assembled via the formation of amide bonds between the terminal functional groups of CdTe-adsorbed 4-aminothiophenol (4-ATP) ligands and CdSe-adsorbed N-hydroxysuccinimide (NHS) ligands. The number of charge acceptors on the surfaces of QDs can greatly influence the rate constant of excited-state charge transfer with QDs capable of accommodating far more acceptors than molecular chromophores. We report here on excited-state electron transfer within heterostructure-forming mixtures of 4-ATP-capped CdTe and NHS-capped CdSe QDs with varying molar ratios of CdTe to CdSe. Photophysical properties and charge transfer were characterized using UV-vis absorption, steady-state emission, and time-resolved emission spectroscopy. As the relative concentration of electron-accepting CdSe QDs within mixtures of 4-ATP-capped CdTe and NHS-capped CdSe QDs increased, the rate and efficiency of electron transfer increased by 100-fold and 7.4-fold, respectively, as evidenced by dynamic quenching of band-edge emission from CdTe QDs. In contrast, for non-interacting mixtures of thiophenol capped CdTe QDs and NHS-capped CdSe QDs, which served as control samples, photophysical properties of the constituent QDs were unperturbed and excited-state charge transfer between the QDs was negligible. Our results reveal that carbodiimide-mediated coupling chemistry can be used to control the relative number of donor and acceptor QDs within heterostructures, which, in turn, enables fine-tuning of charge-transfer dynamics and yields. These amide-bridged dual-QD heterostructures are, thus, intriguing for light harvesting, charge transfer, and photocatalysis. Excited state ; Quantum dot ; Heterojunction ; Cadmium telluride photovoltaics ; Electron transfer ; Electron acceptor ; Electron donor ; Photochemistry ; Chemistry ; Photoluminescence ; Carbodiimide ; Acceptor ; Materials science ; Nanotechnology ; Optoelectronics ; Atomic physics ; Organic chemistry Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Advanced Photocatalysis Techniques
Authors: Shengmin Hu | Jialiang Ye | Ruiqi Liu | Xinhui Zhang
Source: Journal of Semiconductors (article, 2022-08-01)
Field: Materials Science — Materials Chemistry

Valley dynamics of different excitonic states in monolayer WSe<sub>2</sub> grown by molecular beam epitaxy Abstract Monolayer transition-metal dichalcogenides possess rich excitonic physics and unique valley-contrasting optical selection rule, and offer a great platform for long spin/valley lifetime engineering and the associated spin/valleytronics exploration. Using two-color time-resolved Kerr rotation and time-resolved reflectivity spectroscopy, we investigate the spin/valley dynamics of different excitonic states in monolayer WSe 2 grown by molecular beam epitaxy. With fine tuning of the photon energy of both pump and probe beams, the valley relaxation process for the neutral excitons and trions is found to be remarkably different—their characteristic spin/valley lifetimes vary from picoseconds to nanoseconds, respectively. The observed long trion spin lifetime of &gt; 2.0 ns is discussed to be associated with the dark trion states, which is evidenced by the photon-energy dependent valley polarization relaxation. Our results also reveal that valley depolarization for these different excitonic states is intimately connected with the strong Coulomb interaction when the optical excitation energy is above the exciton resonance. Trion ; Exciton ; Picosecond ; Valleytronics ; Monolayer ; Condensed matter physics ; Molecular beam epitaxy ; Photon energy ; Relaxation (psychology) ; Spin (aerodynamics) ; Chemistry ; Photon ; Molecular physics ; Materials science ; Physics ; Epitaxy ; Spintronics ; Laser ; Optics ; Nanotechnology ; Ferromagnetism 2D Materials and Applications ; Perovskite Materials and Applications ; Graphene research and applications
Authors: Chengfeng Xue | I‐Son Ng
Source: Biotechnology and Bioengineering (article, 2022-10-22)
Field: Materials Science — Materials Chemistry

A direct enzymatic evaluation platform (DEEP) to fine‐tuning pyridoxal 5′‐phosphate‐dependent proteins for cadaverine production Pyridoxal 5'-phosphate (pyridoxal phosphate, PLP) is an essential cofactor for multiple enzymatic reactions in industry. However, cofactor engineering based on PLP regeneration and related to the performance of enzymes in chemical production has rarely been discussed. First, we found that MG1655 strain was sensitive to nitrogen source and relied on different amino acids, thus the biomass was significantly reduced when PLP excess in the medium. Then, the six KEIO collection strains were applied to find out the prominent gene in deoxyxylulose-5-phosphate (DXP) pathway, where pdxB was superior in controlling cell growth. Therefore, the clustered regularly interspaced short palindromic repeats interference (CRISPRi) targeted on pdxB in MG1655 was employed to establish a novel direct enzymatic evaluation platform (DEEP) as a high-throughput tool and obtained the optimal modules for incorporating of PLP to enhance the biomass and activity of PLP-dependent enzymes simultaneously. As a result, the biomass has increased by 55% using P<sub>lacI</sub> promoter driven pyridoxine 5'-phosphate oxidase (PdxH) with a trace amount of precursor. When the strains incorporated DEEP and lysine decarboxylase (CadA), the cadaverine productivity was increased 32% due to the higher expression of CadA. DEEP is not only feasible for high-throughput screening of the best chassis for PLP engineering but also practical in fine-tuning the quantity and quality of enzymes. Cadaverine ; Cofactor ; Biochemistry ; Enzyme ; Chemistry ; Transketolase ; Lysine decarboxylase ; Pyridoxal phosphate ; Pyridoxal ; Lysine ; Amino acid ; Putrescine Enzyme Structure and Function ; Microbial Metabolic Engineering and Bioproduction ; Bacterial Genetics and Biotechnology
Authors: B. S. Ezdin | Sergei Vasiljev | D. A. Yatsenko | В.Е. Федоров | Mariia N. Ivanova | V. V. Kalyada | Yu. V. Pakharukov | F. K. Shabiev | A. Е. Зарвин
Source: Siberian Journal of Physics (article, 2022-12-16)
Field: Materials Science — Materials Chemistry

The Synthesis of Carbon Nanoparticles in a Compression Reactor in the Atmosphere of Buffer Gases We investigated the physicochemical aspects of the gas-phase nanopowder synthesis using a cyclic compression reactor. Compression of precursors (methane, ethylene, acetylene) under conditions close to the adiabatic ones in the atmosphere of buffer monatomic gases (argon, helium, neon) was used. The influence of pressure in the reactor and volumetric ratio of precursor/buffer gas mixture on the composition, morphology, and structure of carbon-containing particles representing the pyrolysis product was studied. Complete pyrolysis was observed for all studied precursors, but under different conditions. Thermal decomposition of methane, having the minimum enthalpy of formation, was observed in an atmosphere with argon content 97.5 % at a peak pressure more than 10 MPa. Helium showed limited possibilities for thermal relaxation under the conditions of fast reactions (&lt; 50 ms). Only acetylene with the maximum enthalpy of formation was decomposed in the atmosphere of helium. The solid reaction products represented black colored powders with a bulk density of 20–30 mg/cm 3 . The powders were examined by transmission electron microscopy and scanning electron microscopy, Raman scattering and X-ray diffraction analysis. The particles represent globular bulbous structures up to 100 nm in size, either hollow or filled inside. X-ray diffraction analysis showed the presence of a graphite-like structure with crystallite sizes less than 10 nm in all samples. Raman analysis showed mainly sp 2 hybridization of carbon. The cyclic compression method demonstrates wide range of opportunities for the pyrolysis of hydrocarbons aiming at the production of a variety of carbon structures, which enables for the fine tuning in terms of the yield of products of the required morphology for practical use. Materials science ; Carbon fibers ; Buffer gas ; Analytical Chemistry (journal) ; Argon ; Chemical engineering ; Acetylene ; Chemistry ; Organic chemistry ; Composite material ; Composite number Carbon Nanotubes in Composites ; Graphene research and applications ; Fullerene Chemistry and Applications
Authors: Kening Lang | Ha’Ani-Belle Quichocho | Sarah P. Black | Michael T. K. Bramson | Robert J. Linhardt | David T. Corr | Richard A. Gross
Source: Biomacromolecules (article, 2022-04-25)
Field: Materials Science — Biomaterials

Lipase-Catalyzed Poly(glycerol-1,8-octanediol-sebacate): Biomaterial Engineering by Combining Compositional and Crosslinking Variables This study examined poly(glycerol-1,8-octanediol-sebacate) (PGOS) copolymers with low-level substitution of O (1,8-octanediol) for G (glycerol) units (G/O ratios 0.5:0.5, 0.66:0.33, 0.75:0.25, 0.8:0.2, and 0.91:0.09) prepared in bulk by immobilized <i>Candida antarctica</i> Lipase B (N435) catalysis. The central question explored was the extent that exchanging less than half of poly(glycerol sebacate) (PGS) glycerol units with 1,8-octanediol can be used as a strategy to fine-tune biomaterial properties. Synthesized copolymers having G/O ratios of 0.66:0.33, 0.75:0.25, 0.8:0.2, and 0.91:0.09 have similar molecular weights, where <i>M</i><sub>w</sub> varied from 52,800 to 63,800 g/mol, <i>M</i><sub>n</sub> varied from 5100 to 6450 g/mol, and Đ<sub>M</sub> (molecular mass dispersity, <i>M</i><sub>w</sub>/<i>M</i><sub>n</sub>) values were also similar (8.4-11.4). All of the copolymers were branched, and dendritic glycerol units reached 11% for PGOS-0.91:0.09:1.0. Analysis of DSC second heating scans revealed that copolymers with higher 1,8-octanediol contents have relatively higher <i>T</i><sub>m</sub> and Δ<i>H</i><sub>f</sub> values. Over the copolymer compositional range studied herein, <i>T</i><sub>m</sub> and Δ<i>H</i><sub>f</sub> values varied from 5.3 to 21.1 °C and 8.0 to 23.1 J/g, respectively. Stress-strain curves of PGOS copolymers cured at 140 °C for 48 h exhibited either a unimodal, bimodal, or trimodal response to tensile loading. Varying G/O from 10:1 to 2:1 resulted in significant increases in the peak stress (0.26-4.01 MPa), preyield modulus (0.65-62.59 MPa), failure to strain (64-110%), and failure toughness (0.1-0.56 MPa). This demonstrates that altering the G/O ratio over a narrow compositional range provides biomaterials with widely different yet tunable mechanical properties. Further investigation of PGOS-0.75:0.25:1.0 films revealed that varying the cure conditions from 120 to 160 °C for periods of 24-72 h provides access to biomaterials with a failure strain range from 15 to 224% and Young's modulus from 1.17 to 10.85 MPa. Hence, using the dual variables of compositional variation and changes in cure conditions provides an exciting platform for PGS analogues to optimize material-tissue interactions. Increased contents of 1,8-octanediol slowed <i>in vitro</i> degradation. Slowed degradation of PGOS relative to PGS will be valuable for use in slower healing wounds. Glycerol ; Copolymer ; Biomaterial ; Candida antarctica ; Dispersity ; Polymer chemistry ; Chemistry ; Catalysis ; Lipase ; Miscibility ; Materials science ; Organic chemistry ; Polymer ; Enzyme biodegradable polymer synthesis and properties ; Electrospun Nanofibers in Biomedical Applications ; Antimicrobial agents and applications
Authors: A. Naveen Kumar | D.M. Jnaneshwara | C.R. Ravikumar | H. C. Ananda Murthy | S.C. Prashantha | M.R. Anil Kumar | K.M. Ajay
Source: Advances in Materials Science and Engineering (article, 2022-09-23)
Field: Chemistry — Electrochemistry

A Comparative Cyclic Voltametric Study on Rare Earth (Eu, Sm, Dy, and Tb) Ions Doped La10Si6O27 Nanophosphors for Sensor Application The rare earth (RE = Eu, Sm, Dy, and Tb) ions doped La10Si6O27 nanophosphor was synthesized by a simple solution combustion method. The prepared La10Si6O27:RE3+ nanophosphors (LNPs) were subjected to diverse technical tools for exploring their structural, optical, morphological, and electrochemical features. The structural analysis using powder X-ray diffraction (PXRD) patterns revealed the hexagonal oxy apatite phase for LNPs with a crystallite size in the range of 25–50 nm, and the equivalent was affirmed by image analysis via transmission electron microscopy (TEM). Utilizing DRS data, the bandgap energy (Eg) values were recorded for LNPs. Cyclic voltametric (CV), electrochemical impedance spectroscopy (EIS), and sensor studies were performed using a modified carbon paste electrode of LNPs. The modified LNP electrodes were found to be highly effective in sensing paracetamol in acidic medium with a quick response time of 3 secs for sensing the drugs at 1 mM concentration. All the RE ions Eu3+, Sm3+, Dy3+, and Tb3+ (5 mol%)-doped LNPs exhibited the most promising electrochemical sensing characteristics. Materials science ; Crystallite ; Doping ; Powder diffraction ; Electrochemistry ; Apatite ; Transmission electron microscopy ; Ion ; Analytical Chemistry (journal) ; Dielectric spectroscopy ; Electrode ; Scanning electron microscope ; Nanoparticle ; Nuclear chemistry ; Nanotechnology ; Chemical engineering ; Crystallography ; Optoelectronics ; Composite material ; Physical chemistry ; Chromatography Electrochemical Analysis and Applications ; Luminescence Properties of Advanced Materials ; Gas Sensing Nanomaterials and Sensors
Authors: Narmin Mustafayeva
Source: Azerbaijan Chemical Journal (article, 2022-09-22)
Field: Materials Science — Materials Chemistry

Fe-CONTAINING CARBON NANOTUBES AS CATALYSTS IN THE AEROBIC OXIDATION REACTIONS OF DECALIN AND TETRADECANE This article studies the catalytic activity of multi-walled carbon nanotubes (MWCNTs) in the oxidation reactions of aliphatic and polycyclic hydrocarbons is studied. In order to determine the catalytic activity, MWCNTs catalysts containing 22.8% Fe each were used. Catalyst samples were synthesized from propane gas under optimal conditions determined by CVD method. The experiments were performed at 5 different temperatures (60, 80, 100, 120, 1400C) for 2 hours. No significant change in the oxidation reaction of both hydrocarbons was observed at relatively low temperatures. In the oxidation of decalin, when the reaction temperature rises to 1200C and 1400C, oxidation has already taken place, and the rate of the reaction is directly proportional to the increase in temperature. The same trend can be seen in the oxidation reaction of tetradecane at MWCNTs with temperatures of 120 and 1400C. However, unlike decalin, the MWCNTs sample in tetradecane oxidation showed optimal catalytic performance at 1200C. However, at these temperatures, where oxidation occurs, the oxidation of decalin and tetradecane in an environment without a catalyst is almost non-existent Decalin ; Tetradecane ; Catalysis ; Chemistry ; Propane ; Redox ; Alkane ; Catalytic oxidation ; Carbon fibers ; Chemical engineering ; Organic chemistry ; Materials science Carbon Nanotubes in Composites ; Graphene research and applications ; Thermal properties of materials
Authors: Giada Mannias | Alessandra Scano | Martina Pilloni | Edmond Magner | Guido Ennas
Source: Comments on Inorganic Chemistry (article, 2022-12-19)
Field: Chemistry — Inorganic Chemistry

Tailoring MOFs to Biomedical Applications: A Chimera or a Concrete Reality? The Case Study of Fe-BTC by bio-friendly Mechanosynthesis We point-out an exceptional tailorability of iron(III) trimesate metal-organic framework to bio-friendly conditions. This is particularly attractive in sight of one-pot immobilization of biomolecules for biomedical applications. Synthesis is carried out via mechanochemical approach under green, biocompatible conditions without additional solvents, in just 1 hour, at room temperature. Solvents are proven to be unnecessary to build the framework, in contrast to solution-based methods. Microstructure and thermal stability of the material are not affected by pH. Conversely, textural properties can be tuned by simply varying the amount of base. Mechanosynthesis ; Environmentally friendly ; Chemistry ; Biocompatible material ; Metal-organic framework ; Microstructure ; Nanotechnology ; Thermal stability ; Biomolecule ; Chemical engineering ; Organic chemistry ; Biomedical engineering ; Adsorption ; Materials science Metal-Organic Frameworks: Synthesis and Applications ; Crystallography and molecular interactions ; Nanoplatforms for cancer theranostics
Authors: Piret Pikma | Heigo Ers | Liis Siinor | Jinfeng Zhao | Ove Oll | Tavo Romann | Vitali Grozovski | Carolin Siimenson | Mart Väärtnõu | Maarja Paalo | Riinu Härmas | Karmen Lust | Thomas Thomberg | Alar Jänes | Jaak Nerut | Rutha Jäger | Peeter Valk | Indrek Kivi | Martin Maide | Priit Möller | Rait Kanarbik | Gunnar Nurk | Enn Lust
Source: Journal of Solid State Electrochemistry (article, 2022-12-08)
Field: Chemistry — Electrochemistry

The review of advances in interfacial electrochemistry in Estonia: electrochemical double layer and adsorption studies for the development of electrochemical devices Abstract The electrochemistry nowadays has many faces and challenges. Although the focus has shifted from fundamental electrochemistry to applied electrochemistry, one needs to acknowledge that it is impossible to develop and design novel green energy transition devices without a comprehensive understanding of the electrochemical processes at the electrode and electrolyte interface that define the performance mechanisms. The review gives an overview of the systematic research in the field of electrochemistry in Estonia which reflects on the excellent collaboration between fundamental and applied electrochemistry. Electrochemistry ; Nanotechnology ; Materials science ; Electrode ; Electrolyte ; Chemistry ; Physical chemistry Electrochemical Analysis and Applications ; Electrocatalysts for Energy Conversion ; Analytical Chemistry and Sensors
Authors: Abigail E Reese | Charles Lochenie | Ailsa Geddis | Luana A. Machado | Marcos C. de Souza | Flávia Ferreira de Carvalho Marques | Carlos A. de Simone | Marcos Martins Gouvêa | Leandro F. Pedrosa | Eufrânio N. da Silva Júnior | Marc Vendrell
Source: Chemosensors (article, 2022-01-04)
Field: Materials Science — Materials Chemistry

Rational Design and Synthesis of Large Stokes Shift 2,6-Sulphur-Disubstituted BODIPYs for Cell Imaging Five new disubstituted 2,6-thioaryl-BODIPY dyes were synthesized via selective aromatic electrophilic substitution from commercially available thiophenols. The analysis of the photophysical properties via absorption and emission spectroscopy showed unusually large Stokes shifts for BODIPY fluorophores (70–100 nm), which makes them suitable probes for bioimaging. Selected compounds were evaluated for labelling primary immune cells as well as different cancer cell lines using confocal fluorescence microscopy. BODIPY ; Stokes shift ; Fluorescence ; Chemistry ; Rational design ; Confocal microscopy ; Photochemistry ; Absorption (acoustics) ; Electrophilic substitution ; Confocal ; Microscopy ; Nanotechnology ; Materials science ; Organic chemistry ; Optics Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Porphyrin and Phthalocyanine Chemistry