jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ganesh N Yallappa | D. Nagaraja | U. Chandrashekhara
Source: Research Journal of Nanoscience and Engineering (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

An Efficient Nano-Catalyzed Green Synthesis, Characterization of Substituted Pyrazoles and Study of Their Fluorescence Characteristics To a solution of Cinnamaldehydes (0.01M), 0.5 g of Hydrazine hydrate (0.01M) was added & 2 equiv. of Nano-ZnO was mixed to the solution. The reaction mixture was kept under microwave oven without solvents used (Scheme.1). The Nano- ; Characterization (materials science) ; Catalysis ; Fluorescence ; Nanotechnology ; Combinatorial chemistry ; Chemistry ; Materials science ; Organic chemistry ; Physics ; Composite material ; Optics Multicomponent Synthesis of Heterocycles
Authors: 鉄馬 岸
Source: OUKA (Osaka University Knowledge Archive) (Osaka University) (article, 2018-03-22)
Field: Chemistry — Inorganic Chemistry

Enantioselective Synthesis of Highly Functionalized Heterocycles via Organocatalyzed C–C Bond Forming Reactions Enantioselective synthesis ; Chemistry ; Organocatalysis ; Organic chemistry ; Catalysis ; Combinatorial chemistry Asymmetric Hydrogenation and Catalysis ; Asymmetric Synthesis and Catalysis ; Advanced Synthetic Organic Chemistry
Authors: Stan Najmr
Source: ScholarlyCommons (University of Pennsylvania) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Synthesis, Surface Treatment, And 3d Visualization Of Anisotropic And Multifunctional Rare-Earth Nanocrystals Rare-earth nanocrystals (RE NCs) bring the distinct optical, magnetic, and catalytic properties of bulk rare-earth materials to a solution-processable and biorelevant size-regime. The chemistry of the rare-earth elements also enables the bottom-up synthesis of monodisperse anisotropic NCs with distinct morphologies. Herein, I present the synthesis of four anisotropic rare-earth nanocrystalline systems, namely dysprosium fluoride nanoplatelets, 90Y-doped sodium yttrium fluoride nanophosphors, etched sodium yttrium fluoride nanohourglasses, and ceria-coated palladium nanoflowers, that were elucidated through the use of a semi-combinatorial approach for parallel solvothermal synthesis that was developed over the course of these studies. Methodology for elementally mapping these nano-heterostructures using transmission electron microscopy are also described herein. These systems reveal mechanisms by which the ligand environment and surface treatments can affect the growth of nanocrystalline materials, as well as how these bottom-up approaches can lead to novel opportunities in programmed self-assembly and nanofabrication. Yttrium ; Nanocrystal ; Nanocrystalline material ; Materials science ; Nanotechnology ; Nanolithography ; Dysprosium ; Fluoride ; Transmission electron microscopy ; Dispersity ; Palladium ; Nanoparticle ; Chemical engineering ; Inorganic chemistry ; Catalysis ; Chemistry ; Metallurgy ; Polymer chemistry ; Organic chemistry Nanocluster Synthesis and Applications ; Quantum Dots Synthesis And Properties ; Inorganic Chemistry and Materials
Authors: K Ramakrishna and K V Ramanamurthy
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2018-12-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

DEVELOPMENT AND IN-VITRO AND IN-VIVO STUDIES OF NANOPARTICULATE SYSTEMS CONTAINING METHOTREXATE MTX multi lamellar (MLV) vesicles were prepared by employing thin film hydration technique. Phosphotidyl choline, cholesterol and methotrexate were mixed in a 1000 ml pear-shape flask in a solvent composition of chloroform: methanol (9:1). Glass beads were put into the flask to improve the surface area for film formation. Lipid layer was formed on all the surfaces exposed upon evaporating the organic solvent. The remaining organic solvent that might have left was then eliminated by storing the thin film in a vacuum desiccator overnight. To form MLVs, this layer was hydrated with 10 ml of PBS. This was performed on the Rota vapor. The temperature of water bath and the speed of vortex were 75&amp;ordm;C and 90 rpm, respectively. These parameters were kept constant in all the batches of liposome preparations. For preparation of small unilamellar liposomes, liposomal suspension was sonicated for 15min using an ultra-homogenizer. The prepared Liposomes were characterized for various physicochemical properties such as spanning electron microscope (SEM). Fourier transforms infrared spectroscope (FT-IR) and differential scanning calorimetry (DSC).In-vivo &amp;amp; &amp;nbsp;In-vitro drug release studies showed the extended release up to 9 to 13 days. The release was mainly depends on the Lipid drug ratio. The release kinetics of the drug form prepared Liposomes followed zero order release with diffusion mechanism. DSC and FTIR study showed no drug polymer interaction. \n\n\nKEY WORDS Methotrexate, Cholesterol, Soya Lecithin , Thin film hydration technique &amp;amp; DSC, FTIR. In vivo ; Methotrexate ; In vitro ; Chemistry ; Pharmacology ; Nanotechnology ; Materials science ; Biochemistry ; Medicine ; Biology ; Immunology ; Biotechnology Gold and Silver Nanoparticles Synthesis and Applications ; Electrophoretic Deposition in Materials Science ; Nanoparticles: synthesis and applications
Authors: Yoann Olivier | J.C. Sancho Garcia | L. Muccioli | G. D'Avino | D. Beljonne
Source: ORBi UMONS (article, 2018-09-28)
Field: Materials Science — Materials Chemistry

Computational Design of Thermally Activated Delayed Fluorescence Materials: The Challenge Ahead peer reviewed Fluorescence ; Computational model ; Computational simulation ; Noise (video) Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Photochemistry and Electron Transfer Studies
Authors: Jacob Geri
Source: Deep Blue (University of Michigan) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Bond Activation by Unconventional Lewis Pairs Frustrated Lewis pairs are powerful tools for bond heterolysis in organic and inorganic chemistry. In these systems, an electron-deficient Lewis acid and an electron-rich Lewis base synergistically polarize strong bonds in substrate molecules, forming electrophilic and nucleophilic fragments that can be used in subsequent reactions. However, synergistic bond heterolysis is only possible when reactive Lewis acids and bases are unable to form inert Lewis acid/base adducts with each other. In this monograph, I used a broad definition of what constitutes Lewis acids and bases to design unconventional frustrated Lewis pairs that address significant challenges in catalysis, bioinorganic chemistry, and organofluorine chemistry. First, transition metal catalysts incorporating pendent oxyanion bases were prepared that mediate metal/ligand cooperative H2 and HBPin heterolysis, followed by transfer of electrophilic proton or boryl equivalents and nucleophilic hydrides to nitriles, carbonyl compounds, or carbon dioxide. Next, a reduced Fe(0) center was used as a Lewis base in combination with triorganoborane and alkali cation Lewis acids to synergistically weaken and polarize the N-N triple bond in N2. Polarization of N2 was then exploited in selective -N, rather than -Fe, protonation reactions. Finally, a weak borazine-based Lewis acid was used in combination with strong bases to deprotonate HCF3 and HCF2R. The incipient CF3- and CF2R- anions, typically highly unstable, were captured and stabilized by borazine to form stable fluoroalkylation reagents, which react like traditional Grignard reagents. Overall, these systems demonstrate the generality and utility of the frustrated Lewis pair concept. Bond ; Lewis acids and bases ; Chemistry ; Economics ; Organic chemistry Organoboron and organosilicon chemistry ; Synthesis and characterization of novel inorganic/organometallic compounds ; Inorganic Chemistry and Materials
Authors: Gustavo M. Dalpian
Source: arXiv (Cornell University) (preprint, 2018-10-01)
Field: Materials Science — Materials Chemistry

Spins in Semiconductor Nanocrystals Semiconductor nanocrystals are being used as hosts to trap and manipulate single spins. Spins in nanocrystals can have different properties than their bulk counterparts, owing both to quantum confinement and surface effects. We will show that spins can be generated in nanocrystals by the insertion of impurities, either magnetic or not, or by magnetic polarons present at dangling bonds at their surfaces. This chapter reports theoretical contributions to this field, where the Density Functional Theory is used to simulate these functionalized nanocrystals. Spins ; Nanocrystal ; Dangling bond ; Polaron ; Condensed matter physics ; Semiconductor ; Quantum dot ; Materials science ; Impurity ; Magnetic semiconductor ; Magnetic field ; Nanotechnology ; Physics ; Optoelectronics ; Quantum mechanics ; Electron ; Silicon Quantum Dots Synthesis And Properties ; Magnetic Properties and Synthesis of Ferrites ; Nanocluster Synthesis and Applications
Authors: Juan P. Mora‐Fuentes | Alberto Riaño-Carnerero | Diego Cortizo‐Lacalle | Akinori Saeki | Manuel Melle‐Franco | Aurelio Mateo‐Alonso
Source: ChemRxiv (preprint, 2018-11-15)
Field: Chemistry — Organic Chemistry

Giant Star-Shaped Nitrogen-Doped Nanographenes Star-shaped nanographenes are large monodisperse polycyclic aromatic hydrocarbons that extend in size beyond the nanometer and have shown a lot of promise in a wide range of applications including electronics, energy conversion and sensing. Herein we report a new family of giant star-shaped N-doped nanographenes with diameters up to 6.5 nm. Furthermore, the high solubility of this SNG family in neutral organic solvents at room temperature allowed a complete structural, optoelectronic and electrochemical characterisation, which together with charge transport studies illustrate their n-type semiconducting character. Doping ; Nanometre ; Materials science ; Star (game theory) ; Dispersity ; Nanotechnology ; Solubility ; Organic electronics ; Electrochemistry ; Optoelectronics ; Chemistry ; Physics ; Electrode ; Organic chemistry ; Physical chemistry ; Polymer chemistry ; Astrophysics Synthesis and Properties of Aromatic Compounds ; Graphene research and applications ; Conducting polymers and applications
Authors: Nicolas Gaeng
Source: Infoscience (Ecole Polytechnique Fédérale de Lausanne) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Total Synthesis of Alstilobanine C, Undulifoline and Alstilobanine B The total synthesis of pentacyclic monoterpene indole alkaloids is the focus of this thesis. Total syntheses of (±)-alstilobanine C, (±)-undulifoline and (±)-alstilobanine B, three natural products from the Ulean family of alkaloids, were accomplished. The characteristic features of our synthesis included: a) a domino sequence involving a highly diastereoselective Michael addition followed by chemoselective C-acylation of the resulting enolate by Mander¿s ester; b) an unprecedented Lewis acid mediated intramolecular addition of enolate to oxonium, generated in situ from MOM protective group; c) a sequence of chemoselective reduction/indolization/intramolecular aza-Michael addition. This domino process afforded directly the (±)-alstilobanine C, a pentacyclic monoterpene indole alkaloid in 87% yield. Reductive N-methylation of (±)-alstilobanine C provided (±)-undulifoline which, upon N-oxidation, was further converted to (±)-alstilobanine B. Enantioselective total synthesis of the same natural products through a different synthetic route is presented. After exploring different unsuccessful strategies, an enzymatic desymmetrization of a meso compound was adopted for the synthesis of enantioenriched cyclopentenone intermediate. Applying the two domino sequence developed previously, namely, Michael addition/C-acylation and oxepane formation, an efficient synthesis of the oxobicyclo[4.2.1]nonane was realized. A palladium-catalyzed decarboxylative cross-coupling, a methodology developed in our group, afforded an advanced bicyclic intermediate with all the carbon and functional groups needed to accomplish the total synthesis. However, conversion of the vinyl group to alkylazide or its synthetic equivalent proved to be difficult in spite of the efforts dedicated to this seemingly trivial transformation. Computer science Chemical synthesis and alkaloids ; Alkaloids: synthesis and pharmacology ; Plant-based Medicinal Research
Authors: Tom Wieme | Berten Augustyns | Dagmar D’hooge | Ludwig Cardon
Source: Ghent University Academic Bibliography (Ghent University) (article, 2018-01-01)
Field: Materials Science — General Materials Science

Increased thermal conductivity of thermoplastic composites by manipulation of filler orientation Composite material ; Thermoplastic composites ; Filler (materials) ; Materials science ; Thermal conductivity ; Thermoplastic ; Orientation (vector space) ; Mathematics ; Geometry Material Properties and Applications ; Additive Manufacturing and 3D Printing Technologies ; Epoxy Resin Curing Processes
Authors: Daniele Filippi
Source: Padua@research (University of Padova) (article, 2018-11-30)
Field: Materials Science — Materials Chemistry

Local Fluidization of Concentrated Emulsion in Microfluidic Channels Textured at the Droplet Scale The rheology of soft-flowing systems, such as concentrated emulsions, foams, gels, slurries, colloidal glasses and related complex fluids, has a larger and larger impact in modern science and engineering. Much of the fascination of these systems stems from the fact that they do not fall within any of three basic states of matter, gas-liquid-solid, but live rather on a moving border between them. To understand the flow mechanism, it is necessary to have a look at the micro-scale dynamics of its constituents (i.e, droplets for emulsions, bubbles for foams, blobs for gels, etc.). In fact, in these fluids, the flow occurs via successive elastic deformations and plastic rearrangements, which create fragile regions enhancing the “fluidization” of the material. Despite the fluidization of Soft Glassy Materials (SGMs) is strongly affected by the surface roughness, the role played by the density, the orientation and the periodicity of rough elements has not been quantitatively addressed so far. In fact, predict and control the flow of SGMs is particularly important for an ample variety of technological applications from food to pharmaceutical industries. &#13;\nIn this work, we study the flow of concentrated emulsions in microfluidic channels, one wall of which is patterned with micron-size grooves with different patterns. Using equally spaced grooves, we find a scaling law describing the roughness-induced fluidization as a function of the density of the grooves, thus fluidization can be predicted and quantitatively regulated. Furthermore, we quantitatively report the existence of two physically different scenarios. When the gap is large, compared to the droplets in the emulsion, the droplets hit the solid obstacles and easily escape scrambling with their neighbors. Conversely, as the gap spacing is reduced, droplets get trapped inside, creating a “soft roughness” layer, i.e., a complementary series of deformable posts. Introducing an asymmetrical micro-roughness (herringbone pattern), the flow presents, in turn an asymmetric behavior. The emulsion flows faster in the same direction of the herringbone groove respect when it flows in the opposite direction.&#13;\nOur experimental observations are suitably complemented and confirmed by lattice Boltzmann simulations. These numerical simulations are key to highlight the change in the spatial distribution of the plastic rearrangements caused by surface roughness and to elucidate the micro-mechanics of the roughness induced fluidization.&#13;\n Fluidization ; Materials science ; Microfluidics ; Rheology ; Flow (mathematics) ; Mechanics ; Scaling ; Soft matter ; Surface finish ; Scale (ratio) ; Colloid ; Nanotechnology ; Composite material ; Chemical engineering ; Thermodynamics ; Physics ; Fluidized bed ; Geometry Pickering emulsions and particle stabilization ; Fluid Dynamics and Heat Transfer ; Rheology and Fluid Dynamics Studies
Authors: Salvador Cardona‐Serra | Alejandro Gaita‐Ariño
Source: arXiv (Cornell University) (preprint, 2018-01-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Vanadyl dithiolate single molecule transistors: the next spintronic\n frontier? The role of Chemistry in the road towards quantum devices is the design of\nelementary pieces with a built-in function. A brilliant example is the use of\nmolecular transistors as nuclear spin detectors, which, up to now, has been\nimplemented only on [TbPc$_2$]$^-$. We argue that this is an artificial\nconstraint and critically discuss the limitations of current theoretical\napproaches to assess the potential of molecules for their use in spintronics.\nIn connection with this, we review the recent progress in the preparation of\nhighly coherent spin qubits based on vanadium dithiolate complexes and argue\nthat the use of vanadyl dithiolates as single molecule transistors to read and\ncontrol a triple nuclear spin qubit could give rise to new phenomena, notably\nincluding a low-current nuclear spin detection scheme by means of a spin valve\neffect.\n Spintronics ; Qubit ; Spin (aerodynamics) ; Nanotechnology ; Transistor ; Molecule ; Chemistry ; Physics ; Materials science ; Quantum ; Quantum mechanics Organic and Molecular Conductors Research ; Magnetism in coordination complexes ; Molecular Junctions and Nanostructures
Authors: Cédric Barroo | Austin J. Akey | David C. Bell
Source: Microscopy and Microanalysis (article, 2018-08-01)
Field: Materials Science — Materials Chemistry

Crystallography at the Nanoscale: t-EBSD Study of npAu Catalysts info:eu-repo/semantics/nonPublished Electron backscatter diffraction ; Nanoscopic scale ; Materials science ; Catalysis ; Crystallography ; Nanotechnology ; Metallurgy ; Chemistry ; Microstructure ; Organic chemistry Machine Learning in Materials Science ; Nanoporous metals and alloys ; Advanced Materials Characterization Techniques
Authors: Salvador Cardona‐Serra | Alejandro Gaita‐Ariño
Source: arXiv (Cornell University) (preprint, 2018-01-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Vanadyl dithiolate single molecule transistors: the next spintronic frontier? The role of Chemistry in the road towards quantum devices is the design of elementary pieces with a built-in function. A brilliant example is the use of molecular transistors as nuclear spin detectors, which, up to now, has been implemented only on [TbPc$_2$]$^-$. We argue that this is an artificial constraint and critically discuss the limitations of current theoretical approaches to assess the potential of molecules for their use in spintronics. In connection with this, we review the recent progress in the preparation of highly coherent spin qubits based on vanadium dithiolate complexes and argue that the use of vanadyl dithiolates as single molecule transistors to read and control a triple nuclear spin qubit could give rise to new phenomena, notably including a low-current nuclear spin detection scheme by means of a spin valve effect. Spintronics ; Qubit ; Spin (aerodynamics) ; Nanotechnology ; Transistor ; Molecule ; Chemistry ; Physics ; Materials science ; Quantum ; Quantum mechanics Organic and Molecular Conductors Research ; Magnetism in coordination complexes ; Molecular Junctions and Nanostructures
Authors: Chunshui Yu
Source: Data Archiving and Networked Services (DANS) (article, 2018-05-22)
Field: Materials Science — Materials Chemistry

3D mixed hybrid FE modeling of swelling ionized hydrogels 3D mixed hybrid FE modeling of swelling ionized hydrogels Self-healing hydrogels ; Swelling ; Materials science ; Composite material ; Polymer chemistry High voltage insulation and dielectric phenomena ; Material Properties and Processing ; Textile materials and evaluations
Authors: Elise Lemasson
Source: theses.fr (ABES) (preprint, 2018-01-18)
Field: Chemistry — Spectroscopy

Liquid and supercritical chromatographic strategies for analysis of drug candidates Le profilage d’impuretés de candidats médicaments est une préoccupation majeure des industries pharmaceutiques. L’identification et la quantification des impuretés doivent être strictement contrôlées pour assurer l’efficacité et la toxicité limitée du principe actif. Il est donc nécessaire de disposer de méthodes analytiques performantes afin de s’assurer que l’ensemble des impuretés est identifié. L’HPLC phase inverse sur phase C18 reste aujourd’hui la méthode de choix pour cette tâche. Cependant, il arrive que cette méthode échoue, notamment lorsque le principe actif n’est pas suffisamment retenu sur la colonne ou que les impuretés ne sont pas parfaitement séparées du composé principal. Il est alors essentiel de pouvoir se tourner vers des méthodes analytiques alternatives et complémentaires.Ce travail de recherche traite du développement et de l’évaluation de méthodes analytiques alternatives à l’HPLC phase inverse sur phase C18 pour le profilage d’impuretés de principes actifs pharmaceutiques. L’HPLC phase inverse sur d’autres phases stationnaires, l’HPLC mixed-mode ainsi que la SFC ont été explorées et leurs performances chromatographiques comparées. La comparaison et l’étude des différentes méthodes ont permis de proposer une stratégie d’analyse du candidat médicament. Chromatography ; Supercritical fluid ; Drug ; Chemistry ; Medicine ; Pharmacology ; Organic chemistry Analytical Chemistry and Chromatography ; Chromatography in Natural Products
Authors: Samuel Cameron | Laurent Kreplak | Andrew D. Rutenberg
Source: arXiv (Cornell University) (preprint, 2018-02-23)
Field: Materials Science — Biomaterials

Polymorphism of stable collagen fibrils Collagen fibrils are versatile self-assembled structures that provide mechanical integrity within mammalian tissues. The radius of collagen fibrils vary widely depending on experimental conditions \textit{in vitro} or anatomical location \textit{in vivo}. Here we explore the variety of thermodynamically stable fibril configurations that are available. We use a liquid crystal model of radial collagen fibril structure with a double-twist director field. Using a numerical relaxation method we show that two dimensionless parameters, the ratio of saddle-splay to twist elastic constants $ k_{24}/K_{22}$ and the ratio of surface tension to chiral strength $\hatγ \equiv γ/(K_{22}q)$, largely specify both the scaled fibril radius and the associated surface twist of equilibrium fibrils. We find that collagen fibrils are the stable phase with respect to the cholesteric phase only when the reduced surface tension is small, $\hatγ \lesssim 0.2$. Within this stable regime, collagen fibrils can access a wide range of radii and associated surface twists. Remarkably, we find a maximal equilibrium surface twist of $0.33$ rad ($19^{\text{o}}$). Our results are compatible with corneal collagen fibrils, and we show how the large surface twist is needed to explain the narrow distribution of corneal fibril radii. Conversely, we show how small surface twist is required for the thermodynamic stability of tendon fibrils in the face of considerable polydispersity of radius. Fibril ; Twist ; RADIUS ; Materials science ; Crystallography ; Surface tension ; Liquid crystal ; Dimensionless quantity ; Biophysics ; Chemistry ; Chemical physics ; Physics ; Thermodynamics ; Geometry Collagen: Extraction and Characterization ; Proteoglycans and glycosaminoglycans research ; Connective tissue disorders research
Authors: Andreas D. Benischke
Source: Electronic Theses of LMU Munich (Ludwig-Maximilians-Universität München) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

New Iron-, Cobalt- and Nickel-catalyzed cross-coupling reactions for being the greatest labmates one could imagine and for tolerating my special kind of music and sometimes stressed mood in the lab.Thanks Marcel for creating an awesome atmosphere in the lab during my studies, for your motivation and for being one of the best lab mates Nickel ; Cobalt ; Catalysis ; Chemistry ; Coupling (piping) ; Metallurgy ; Materials science ; Inorganic chemistry ; Organic chemistry Catalytic Cross-Coupling Reactions ; Asymmetric Hydrogenation and Catalysis