jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Giovanni Formica | Michela Talò | Giulia Lanzara | Walter Lacarbonara
Source: Journal of Applied Mechanics (article, 2018-12-03)
Field: Materials Science — Materials Chemistry

Parametric Identification of Carbon Nanotube Nanocomposites Constitutive Response Hysteresis due to stick-slip energy dissipation in carbon nanotube (CNT) nanocomposites is experimentally observed, measured, and identified through a one-dimensional (1D) phenomenological model obtained via reduction of a three-dimensional (3D) mesoscale model. The proposed model is shown to describe the nanocomposite hysteretic response, which features the transition from the purely elastic to the post-stick-slip behavior characterized by the interfacial frictional sliding motion between the polymer chains and the CNTs. Parametric analyses shed light onto the physical meaning of each model parameter and the influence on the material response. The model parameters are determined by fitting the experimentally acquired force–displacement curves of CNT/polymer nanocomposites using a differential evolution algorithm. Nanocomposite beam-like samples made of a high performance engineering polymer and high-aspect-ratio CNTs are fabricated and tested in a bending mode at increasing deflection amplitudes. The entire time histories of the restoring force are fitted by the model through a unique set of parameters. The parameter identification is carried out for nanocomposites with various CNT weight fractions, so as to highlight the model capability to identify a wide variety of nanocomposite hysteretic behaviors through a fine tuning of its constitutive parameters. By exploiting the proposed model, a nanostructured material design and its optimization are made possible toward the exploitation of these promising materials for engineering applications. Materials science ; Carbon nanotube ; Nanocomposite ; Dissipation ; Composite material ; Slip (aerodynamics) ; Hysteresis ; Polymer nanocomposite ; Deflection (physics) ; Phenomenological model ; Solid mechanics ; Stiffness ; Parametric statistics ; Flexural rigidity ; Mechanics ; Classical mechanics ; Thermodynamics ; Physics Carbon Nanotubes in Composites ; Force Microscopy Techniques and Applications ; Mechanical and Optical Resonators
Authors: Swati Mohan | Yuanbing Mao
Source: Journal of The Electrochemical Society (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Dependence of (Photo)electrochemical Properties on Geometry Factors of Hydrothermally Synthesized Delafossite Copper Gallium Oxide CuGaO<sub>2</sub>toward Oxygen Evolution Reaction The recent surge of alternative clean energy with minimal environmental impact in a cost-effective way has attracted great interest in the exploration of new materials and/or structures as efficient electrodes for industry-level (photo)electrochemical water splitting. Delafossites with a general formula of ABO2 as a type of earth-abundant materials are expected to serve as ideal alternatives for water electrolysis. In this work, by fine-tuning the synthesis procedure of delafossite CuGaO2 via surfactant assisted hydrothermal route, we investigated the dependence of their (photo)electrochemical properties on geometry factors. More specifically, the synthesized CuGaO2 samples were characterized by powder XRD, SEM, EDX, XPS, FT-IR, UV-Vis, and BET surface area measurements. Moreover, their electrocatalytic and photoelectrocatalytic performance were tested and compared toward oxygen evolution reaction (OER). Based on cyclic voltammetry and electrochemical impedance spectroscopy, their onset potential, current density, Tafel slope, charge transfer resistance, and stability were investigated. It was found that the synthesized delafossite CuGaO2 nanoflakes with the smallest dimensions exhibited the best (photo)electrocatalytic performance and could serve as a potential candidate for cost-effective and active electrode material. Delafossite ; Tafel equation ; Water splitting ; Oxygen evolution ; Electrochemistry ; Dielectric spectroscopy ; Cyclic voltammetry ; Materials science ; Oxide ; Chemical engineering ; Inorganic chemistry ; Electrode ; Chemistry ; Physical chemistry ; Catalysis ; Metallurgy ; Photocatalysis ; Organic chemistry Copper-based nanomaterials and applications ; ZnO doping and properties ; Advanced Photocatalysis Techniques
Authors: Elena Chistè | A. Ghafarinazari | Marta Donini | Véronique Cremers | Jolien Dendooven | Christophe Detavernier | Donatella Benati | Marina Scarpa | Stefano Dusi | N. Daldosso
Source: Journal of Materials Chemistry B (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

TiO<sub>2</sub>-coated luminescent porous silicon micro-particles as a promising system for nanomedicine Porous silicon (pSi) is a sponge-like material obtained by electrochemical etching of a crystalline silicon wafer. Due to quantum confinement effects, this material is photoluminescent and this is a fundamental property from the perspective of bioimaging applications. Limitations in nanomedicine to the use of photoluminescent pSi structures are mainly due to optical quenching in an aqueous environment and to the adverse effects of reactive groups introduced by etching procedures. In this work, we exploited an inorganic TiO<sub>2</sub> coating of pSi microparticles by Atomic Layer Deposition (ALD) that resulted in optical stability of pSi particles in a biological buffer (e.g. PBS). The use of a rotary reactor allows deposition of a uniform coating on the particles and enables a fine tuning of its thickness. The ALD parameters were optimized and the photoluminescence (PL) of pSi-TiO<sub>2</sub> microparticles was stabilized for more than three months without any significant effect on their morphology. The biocompatibility of the coated microparticles was evaluated by analyzing the release of cytokines and superoxide anion (O<sub>2</sub> <sup>-</sup>) by human dendritic cells, which play an essential role in the regulation of inflammatory and immune responses. We demonstrated that the microparticles per se are unable to significantly damage or stimulate human dendritic cells and therefore are suitable candidates for nanomedicine applications. However, a synergistic effect of the microparticles with bacterial products, which are known to stimulate immune-response, was observed, indicating that a condition unfavorable to the use of inorganic nanomaterials in biological systems is the presence of infection diseases. These results, combined with the proved PL stability in biological buffers, open the way for the use of pSi-TiO<sub>2</sub> microparticles as promising materials in nanomedicine, but their ability to increase immune cell activation by other agonists should be considered and even exploited. Materials science ; Nanomedicine ; Porous silicon ; Nanotechnology ; Luminescence ; Porosity ; Silicon ; Chemical engineering ; Nanoparticle ; Optoelectronics ; Composite material ; Engineering Silicon Nanostructures and Photoluminescence ; Nanowire Synthesis and Applications ; Carbon Nanotubes in Composites
Authors: Tommaso Margola | Katsuhiko Satoh | Giacomo Saielli
Source: Crystals (article, 2018-09-20)
Field: Materials Science — Materials Chemistry

Comparison of the Mesomorphic Behaviour of 1:1 and 1:2 Mixtures of Charged Gay-Berne GB(4.4,20.0,1,1) and Lennard-Jones Particles We present a Molecular Dynamics study of mixtures of charged Gay-Berne (GB) ellipsoids and spherical Lennard-Jones (LJ) particles as models of ionic liquids and ionic liquid crystals. The GB system is highly anisotropic (GB(4.4,20.0,1,1)) and we observe a rich mesomorphism, with ionic nematic and smectic phases in addition to the isotropic mixed phase and crystalline phases with honeycomb structure. The systems have been investigated by analyzing the orientational and translational order parameters, as well as radial distribution functions. We have directly compared 1:1 mixtures, where the GB and LJ particles have a charge equal in magnitude and opposite in sign, and 1:2 mixtures where the number of LJ particles is twice as large compared to the GB and their charge half in magnitude. The results highlight the role of the long-range isotropic electrostatic interaction compared to the short-range van der Waals anisotropic contribution, and the effect of the stoichiometry on the stability of ionic mesophases. van der Waals force ; Isotropy ; Ionic liquid ; Anisotropy ; Liquid crystal ; Molecular dynamics ; Chemical physics ; Ionic bonding ; Materials science ; Phase (matter) ; Condensed matter physics ; Thermodynamics ; Chemistry ; Computational chemistry ; Physics ; Ion ; Molecule ; Optics ; Organic chemistry Material Dynamics and Properties ; Liquid Crystal Research Advancements ; Surfactants and Colloidal Systems
Authors: Catalina Biglione | Ariel L. Cappelletti | Miriam C. Strumia | Sandra E. Martı́n | Paula M. Uberman
Source: Journal of Nanoparticle Research (article, 2018-05-01)
Field: Chemistry — Organic Chemistry

Magnetic Pd nanocatalyst Fe3O4@Pd for C–C bond formation and hydrogenation reactions Materials science ; Palladium ; Catalysis ; Chemical engineering ; Photochemistry ; Nanotechnology ; Organic chemistry Nanomaterials for catalytic reactions ; Asymmetric Hydrogenation and Catalysis ; Catalytic Cross-Coupling Reactions
Authors: Mengen Wang | Jian‐Qiang Zhong | Darı́o Stacchiola | J. Anibal Boscoboinik | Deyu Lu
Source: The Journal of Physical Chemistry C (article, 2018-09-09)
Field: Chemistry — Inorganic Chemistry

First-Principles Study of Interface Structures and Charge Rearrangement at the Aluminosilicate/Ru(0001) Heterojunction Aluminosilicate bilayer films consisting of corner-sharing [SiO4] and [AlO4] tetrahedra on a metal substrate are important model systems to study zeolite chemistry in heterogeneous catalysis. Understanding the interfacial electronic properties of the aluminosilicate/metal heterojunction is a fundamental step to rationalize the structure–property–function relationship essential to the catalytic activities of the model zeolite. In this work, we use density functional theory (DFT) to investigate the charge rearrangement at the aluminosilicate/Ru(0001) interface, which is attributed to hybridizations between the O pz and Ru dz2 and s orbitals and the subsequent electron redistribution. We found that the energy level alignment at the aluminosilicate/Ru(0001) heterojunction is determined by the surface and interface dipole moments resulting from the charge rearrangements and that the magnitude of these dipole moments can be modified by the aluminum concentration and the surface O coverage on Ru(0001). Aluminosilicate ; Density functional theory ; Heterojunction ; Materials science ; Dipole ; Charge density ; Work function ; Chemical physics ; Electronic structure ; Catalysis ; Computational chemistry ; Metal ; Bilayer ; Charge (physics) ; Chemistry ; Organic chemistry ; Optoelectronics Zeolite Catalysis and Synthesis ; Iron oxide chemistry and applications ; Mesoporous Materials and Catalysis
Authors: Christo N. Nanev
Source: Crystals (article, 2018-11-08)
Field: Materials Science — Materials Chemistry

Peculiarities of Protein Crystal Nucleation and Growth This paper reviews investigations on protein crystallization. It aims to present a comprehensive rather than complete account of recent studies and efforts to elucidate the most intimate mechanisms of protein crystal nucleation. It is emphasized that both physical and biochemical factors are at play during this process. Recently-discovered molecular scale pathways for protein crystal nucleation are considered first. The bond selection during protein crystal lattice formation, which is a typical biochemically-conditioned peculiarity of the crystallization process, is revisited. Novel approaches allow us to quantitatively describe some protein crystallization cases. Additional light is shed on the protein crystal nucleation in pores and crevices by employing the so-called EBDE method (equilibration between crystal bond and destructive energies). Also, protein crystal nucleation in solution flow is considered. Nucleation ; Protein crystallization ; Crystallization ; Crystal (programming language) ; Crystallography ; Crystal growth ; Materials science ; Chemical physics ; Chemistry ; Computer science ; Organic chemistry Enzyme Structure and Function ; Crystallization and Solubility Studies ; Protein Structure and Dynamics
Authors: Ashfaq Afsar | James Westwood | Petr Distler | Laurence M. Harwood | Saeed D. Mohan | Jan John | Fred J. Davis
Source: Tetrahedron (article, 2018-04-14)
Field: Chemistry — Inorganic Chemistry

Separation of Am(III), Cm(III) and Eu(III) by electro-spun polystyrene-immobilized CyMe4-BTPhen Chemistry ; Polystyrene ; Actinide ; Ligand (biochemistry) ; Electrospinning ; Selenium ; Polymer chemistry ; Fiber ; Nuclear chemistry ; Polymer ; Organic chemistry Radioactive element chemistry and processing ; Chemical Synthesis and Characterization ; Extraction and Separation Processes
Authors: Adam Orłowski | Lior Artzi | Pierre‐André Cazade | Melissabye Gunnoo | Edward A. Bayer | Damien Thompson
Source: Physical Chemistry Chemical Physics (article, 2018-01-01)
Field: Materials Science — Biomaterials

On the distinct binding modes of expansin and carbohydrate-binding module proteins on crystalline and nanofibrous cellulose: implications for cellulose degradation by designer cellulosomes Transformation of cellulose into monosaccharides can be achieved by hydrolysis of the cellulose chains, carried out by a special group of enzymes known as cellulases. The enzymatic mechanism of cellulases is well described, but the role of non-enzymatic components of the cellulose-degradation machinery is still poorly understood, and difficult to measure using experiments alone. In this study, we use a comprehensive set of atomistic molecular dynamics simulations to probe the molecular details of binding of the family-3a carbohydrate-binding module (CBM3a) and the bacterial expansin protein (EXLX1) to a range of cellulose substrates. Our results suggest that CBM3a behaves in a similar way on both crystalline and amorphous cellulose, whereas binding of the dual-domain expansin protein depends on the substrate crystallinity, and we relate our computed binding modes to the experimentally measured features of CBM and expansin action on cellulose. Cellulose ; Expansin ; Carbohydrate-binding module ; Degradation (telecommunications) ; Chemistry ; Cellulase ; Carbohydrate ; Cellulosic ethanol ; Biophysics ; Biochemistry ; Chemical engineering ; Computer science ; Biology ; Engineering Advanced Cellulose Research Studies ; Biofuel production and bioconversion ; Polysaccharides and Plant Cell Walls
Authors: V Vekselman | A Khrabry | I Kaganovich | B Stratton | R S Selinsky | Y Raitses
Source: Plasma Sources Science and Technology (article, 2018-01-12)
Field: Materials Science — Materials Chemistry

Quantitative imaging of carbon dimer precursor for nanomaterial synthesis in the carbon arc Delineating the dominant processes responsible for nanomaterial synthesis in a plasma environment requires measurements of the precursor species contributing to the growth of nanostructures. We performed comprehensive measurements of spatial and temporal profiles of carbon dimers (C$_2$) in atmospheric-pressure carbon arc by laser-induced fluorescence. Measured spatial profiles of C$_2$ coincide with the growth region of carbon nanotubes and vary depending on the arc operation mode, which is determined by the discharge current and the ablation rate of the graphite anode. The C$_2$ density profile exhibits large spatial and time variations due to motion of the arc core. A comparison of the experimental data with the simulation results of self-consistent arc modeling shows a good agreement. The model predicts well the main processes determining spatial profiles of carbon dimers (C$_2$). Arc (geometry) ; Carbon fibers ; Graphite ; Carbon nanotube ; Nanomaterials ; Dimer Diamond and Carbon-based Materials Research ; Vacuum and Plasma Arcs ; Laser-Ablation Synthesis of Nanoparticles
Authors: Pedro Silva | Mauro A. P. Gonçalves | Manuela Ramos Silva | Anna Zawadzka | B. Sahraoui | J.A. Paixão
Source: Optical Materials (article, 2018-07-30)
Field: Materials Science — Electronic, Optical and Magnetic Materials

NLO properties of a triphenlyguanidine salt: The importance of pseudo-symmetry Hyperpolarizability ; Supermolecule ; Density functional theory ; Diffraction ; Symmetry (geometry) ; Second-harmonic generation ; Nonlinear optics ; Nonlinear system ; Chemistry ; Materials science ; Condensed matter physics ; Physics ; Optics ; Molecule ; Computational chemistry ; Nonlinear optical ; Quantum mechanics ; Mathematics Nonlinear Optical Materials Research ; Crystal structures of chemical compounds ; Crystallography and molecular interactions
Authors: Kathrin Kettenbach | Laura Reffert | Hanno Schieferstein | Stefanie Pektor | Raphael Eckert | Matthias Miederer | Frank Rösch | Tobias L. Roß
Source: Pharmaceuticals (article, 2018-03-17)
Field: Chemistry — Organic Chemistry

Comparison Study of Two Differently Clicked 18F-Folates—Lipophilicity Plays a Key Role Within the last decade, several folate-based radiopharmaceuticals for Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) have been evaluated; however, there is still a lack of suitable <sup>18</sup>F-folates for clinical PET imaging. Herein, we report the synthesis and evaluation of two novel <sup>18</sup>F-folates employing strain-promoted and copper-catalyzed click chemistry. Furthermore, the influence of both click-methods on lipophilicity and pharmacokinetics of the <sup>18</sup>F-folates was investigated. <sup>18</sup>F-Ala-folate and <sup>18</sup>F-DBCO-folate were both stable in human serum albumin. In vitro studies proved their high affinity to the folate receptor (FR). The lipophilic character of the strain-promoted clicked <sup>18</sup>F-DBCO-folate (logD = 0.6) contributed to a higher non-specific binding in cell internalization studies. In the following in vivo PET imaging studies, FR-positive tumors could not be visualized in a maximum intensity projection images. Compared with <sup>18</sup>F-DBCO-folate, <sup>18</sup>F-Ala-folate (logD = -1.4), synthesized by the copper-catalyzed click reaction, exhibited reduced lipophilicity, and as a result an improved in vivo performance and a clear-cut visualization of FR-positive tumors. In view of high radiochemical yield, radiochemical purity and favorable pharmacokinetics, <sup>18</sup>F-Ala-folate is expected to be a promising candidate for FR-PET imaging. Lipophilicity ; Chemistry ; In vivo ; Click chemistry ; Folate receptor ; Internalization ; Positron emission tomography ; In vitro ; Pharmacokinetics ; Emission computed tomography ; Preclinical imaging ; Stereochemistry ; Biophysics ; Cell ; Combinatorial chemistry ; Biochemistry ; Pharmacology ; Nuclear medicine ; Medicine ; Biology ; Internal medicine Click Chemistry and Applications ; Radiopharmaceutical Chemistry and Applications ; HIV/AIDS drug development and treatment
Authors: Hiroki Tanaka | Hideo Akutsu | Izumi Yabuta | Masashi Hara | Hayuki Sugimoto | Takahisa Ikegami | Takeshi Watanabe | Toshimichi Fujiwara
Source: FEBS Letters (article, 2018-08-20)
Field: Chemistry — Spectroscopy

A novel chitin‐binding mode of the chitin‐binding domain of chitinase A1 from <i>Bacillus circulans </i><scp>WL</scp>‐12 revealed by solid‐state <scp>NMR</scp> Chitin-binding domain of chitinase A1 (ChBD<sub>C</sub><sub>hiA1</sub> ) is characteristic because it binds only to insoluble crystalline chitin. While binding sites of major carbohydrate-binding modules carry multiple aromatic rings aligned on a surface, lethal mutations for ChBD<sub>C</sub><sub>hiA1</sub> were reported only at W687, a location completely different from the site mentioned above, in spite of their similar main-chain folds. Here, the structural mechanism underlying its crystalline chitin binding was uncovered by solid-state NMR. Based on <sup>13</sup> C- and <sup>15</sup> N-signal assignment of microcrystalline ChBD<sub>C</sub><sub>hiA1</sub> , the chemical shift perturbation on chitin binding was carefully examined. The perturbation was greatest at W687 and nonaromatic residues surrounding it, revealing their direct involvement in chitin binding. These residues and Q679 should provide a novel chitin-binding platform parallel to the W687 ring. Chitin ; Bacillus circulans ; Chitinase ; Chemistry ; Binding site ; Binding domain ; Stereochemistry ; Biochemistry ; Crystallography ; Chitosan ; Enzyme Advanced NMR Techniques and Applications ; Studies on Chitinases and Chitosanases ; Legume Nitrogen Fixing Symbiosis
Authors: Shu Y. Liao | Myungwoon Lee | Mei Hong
Source: Journal of Structural Biology (article, 2018-03-01)
Field: Chemistry — Spectroscopy

Interplay between membrane curvature and protein conformational equilibrium investigated by solid-state NMR Membrane curvature ; Biophysics ; Transmembrane protein ; Membrane protein ; Membrane ; Transmembrane domain ; Chemistry ; Lipid bilayer ; Lipid bilayer fusion ; Protein structure ; Helix (gastropod) ; Curvature ; Crystallography ; Peripheral membrane protein ; Integral membrane protein ; Biochemistry ; Biology Advanced NMR Techniques and Applications ; Bacteriophages and microbial interactions ; Infectious Encephalopathies and Encephalitis
Authors: Fatemeh Amerikheirabadi | Carlos M. Diaz | Neetha Mohan | Rajendra R. Zope | Tunna Baruah
Source: Physical Chemistry Chemical Physics (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

A DFT analysis of the ground and charge-transfer excited states of Sc<sub>3</sub>N@I<sub>h</sub>–C<sub>80</sub> fullerene coupled with metal-free and zinc-phthalocyanine Endohedral metallofullerenes and phthalocyanine derivatives are recognized as excellent active materials in organic photovoltaics (OPVs). The tri-metallic nitride endohedral C80 fullerenes have greater absorption coefficients in the visible region and electron-accepting abilities similar to C60, which can allow for higher efficiencies in OPV devices. In this work, we have investigated the ground and charge transfer excited states of two co-facial donor-acceptor (D-A) molecular conjugates formed by the non-covalent coupling of trimetallic nitride endohedral fullerene (Sc3N@Ih-C80) with metal-free (H2Pc) and zinc-phthalocyanine (ZnPc) chromophores using DFT calculations. The charge transfer (CT) excitation energies are calculated using the perturbative delta-SCF method that enforces orthogonality between the ground and excited states. The binding energies calculated using the PBE and DFT-D3 methods indicate that the dispersion effects play an important role in the stabilization of these complexes. The ground state dipole moment of the Sc3N@C80-H2Pc dyad is much larger than that of Sc3N@C80-ZnPc, but this is reversed in the excited state where the dipole moment of Sc3N@C80-ZnPc increases significantly. The lowest few excitation energies in the gas phase for the two complexes are very close, in the range of 1.51-2.66 eV for Sc3N@C80-ZnPc and 1.51-2.71 eV for the Sc3N@C80-H2Pc complex. However, the lower ionization potential and lower exciton binding energy make the Sc3N@C80-ZnPc dyad a better candidate for OPVs as compared to the Sc3N@C80-H2Pc dyad. Excited state ; Fullerene ; Charge (physics) ; Zinc ; Ground state ; Metal ; Atomic physics ; Chemistry ; Computational chemistry ; Chemical physics ; Molecular physics ; Materials science ; Physics ; Quantum mechanics ; Organic chemistry Fullerene Chemistry and Applications ; Organic Electronics and Photovoltaics ; Polymer Nanocomposite Synthesis and Irradiation