jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Emilian Georgescu | Anca Oancea | Florentina Georgescu | Alina Nicolescu | Elena Iulia Oprita | Lucian Vladulescu | Marius-Constantin Vladulescu | Florin Oancea | Sergiu Shova | Călin Deleanu
Source: PLoS ONE (article, 2018-07-10)
Field: Chemistry — Organic Chemistry

Schiff bases containing a furoxan moiety as potential nitric oxide donors in plant tissues Stable Schiff bases containing a furoxan moiety are synthesized as single regioisomers by the reaction of 3-methyl-2-oxy-furazan-4-carbaldehydewith various amino compounds at room temperature. The structures of synthesized compounds were fully characterized by multinuclear NMR spectroscopy and X-ray crystallography. The effect of synthesized Schiff bases containing a furoxan moiety on biological generation of reactive oxygen species and nitric oxide in plant tissues was investigated for the first time by fluorescence microscopy and the released NO identified as nitrite with Griess reagent. There is a good correlation between the biological generation of NO determined by fluorescence microscopy and with Griess reagent. Some of the synthesized compounds exhibited both nitric oxide and reactive oxygen species generation abilities and represent potential NO donors in plant tissues. Furoxan ; Griess test ; Moiety ; Nitric oxide ; Chemistry ; Reagent ; Reactive oxygen species ; Fluorescence ; Nitrite ; Organic chemistry ; Biochemistry ; Nitrate Synthesis and Biological Evaluation ; Vanadium and Halogenation Chemistry ; Oxidative Organic Chemistry Reactions
Authors: Takuya Ohzono | Tetsuo Yatabe | Chenguang Wang | Aiko Fukazawa | Shigehiro Yamaguchi
Source: Communications Chemistry (article, 2018-08-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Negative fluorescence anisotropy of phosphole oxide-based dyes in nematic liquid crystals Abstract It is important to understand how solute molecules align in anisotropic media such as liquid crystals and biological membranes. Alignment of fluorescent probes used in polarised fluorescence microscopy is of interest because anisotropy of the medium is indirectly estimated through the fluorescence intensity originating from the transition dipole moments fixed on the molecule. Here we report fluorescence anisotropies of a series of phosphole oxide-based dyes with an elongated π -conjugated system, along which the transition dipole moment lies, in nematic liquid crystals. We observe that as the number, size and rigidity of substituents protruding from the π -conjugated plane increase, the transition dipole moment tends to tilt away from the nematic director over the magic angle, ~54.7°, showing conspicuous negative fluorescence anisotropy. Analysis of molecular shapes suggests that the substitutions modulate the interaction with the nematic mean field, impacting the direction of the principal molecular axis aligned with the nematic director. Liquid crystal ; Phosphole ; Anisotropy ; Fluorescence ; Dipole ; Materials science ; Transition dipole moment ; Fluorescence anisotropy ; Molecular physics ; Crystallography ; Chemical physics ; Condensed matter physics ; Chemistry ; Optics ; Physics ; Stereochemistry ; Organic chemistry ; Optoelectronics Liquid Crystal Research Advancements ; Photochemistry and Electron Transfer Studies ; Photoreceptor and optogenetics research
Authors: Mikko Mäkelä | Paul Geladi
Source: Scientific Reports (article, 2018-07-05)
Field: Chemistry — Analytical Chemistry

Hyperspectral near infrared imaging quantifies the heterogeneity of carbon materials For many applications heterogeneity is a direct indicator of material quality. Reliable determination of chemical heterogeneity is however not a trivial task. Spectral imaging can be used for determining the spatial distribution of an analyte in a sample, thus transforming each pixel of an image into a sampling cell. With a large amount of image pixels, the results can be evaluated using large population statistics. This enables robust determination of heterogeneity in biological samples. We show that hyperspectral imaging in the near infrared (NIR) region can be used to reliably determine the heterogeneity of renewable carbon materials, which are promising replacements for current fossil alternatives in energy and environmental applications. This method allows quantifying the variation in renewable carbon and other biological materials that absorb in the NIR region. Reliable determination of heterogeneity is also a valuable tool for a wide range of other chemical imaging applications. Hyperspectral imaging ; Chemical imaging ; Pixel ; Sampling (signal processing) ; Remote sensing ; Spatial heterogeneity ; Spectral imaging ; Computer science ; Environmental science ; Biological system ; Artificial intelligence ; Ecology ; Computer vision ; Geology ; Biology Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Advanced Chemical Sensor Technologies
Authors: Juan V. Alegre‐Requena | Marleen Häring | Isaac G. Sonsona | Alex Abramov | Eugenia Marqués‐López | Raquel P. Herrera | David Díaz Díaz
Source: Beilstein Journal of Organic Chemistry (article, 2018-08-06)
Field: Materials Science — Biomaterials

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides We describe the preparation and characterization of two new unsymmetrical squaramide-based organogelators. The synthesis of the compounds was carried out by subsequent amine condensations starting from dimethyl squarate. The design of the gelators involved a squaramide core connected on one side to a long aliphatic chain and on the other side to a glutamic acid residue. The gelator bearing the free carboxylic groups showed a lower gelation capacity than its precursor diester derivative. Some selected gels were further studied by infrared spectroscopy, rheology and electron microscopy. Critical gelation concentrations and gel-to-sol transition temperatures were also determined for each case. In addition, the superior squaramide diester gelator was compared with an analogue triazole-based gelator in terms of critical gelation concentration, gelation kinetics and thermal phase transition. Squaramide ; Chemistry ; Supramolecular chemistry ; Residue (chemistry) ; Amine gas treating ; Infrared spectroscopy ; Kinetics ; Organic chemistry ; Polymer chemistry ; Organocatalysis ; Catalysis ; Enantioselective synthesis ; Molecule Supramolecular Self-Assembly in Materials ; Lipid Membrane Structure and Behavior ; RNA Interference and Gene Delivery
Authors: Matteo Di Giosia | Francesco Valle | Andrea Cantelli | Andréa Bottoni | Francesco Zerbetto | Matteo Calvaresi
Source: Preprints.org (preprint, 2018-03-19)
Field: Chemistry — Organic Chemistry

C&lt;sub&gt;60&lt;/sub&gt; Bioconjugation with Proteins: Towards a Palette of Carriers for All pH Ranges The high hydrophobicity of fullerenes and the resulting formation of aggregates in aqueous solutions hamper the possibility of their exploitation in many technological applications. Noncovalent bioconjugation of fullerenes with proteins is an emerging approach for their dispersion in aqueous media. Contrary to covalent functionalization, bioconjugation preserves the physicochemical properties of the carbon nanostructure. The unique photophysical and photochemical properties of fullerenes are then fully accessible for applications in nanomedicine, sensoristic, biocatalysis and materials science fields. And yet, proteins are not universal carriers. Their stability depends on the biological conditions for which they have evolved. Here we present two model systems based on pepsin and trypsin. These proteins have opposite net charge at physiological pH. They recognize and disperse C60 in water. UV-Vis spectroscopy, zeta-potential and atomic force microscopy analysis demonstrates that the hybrids are well dispersed and stable in a wide range of pH&amp;rsquo;s and ionic strengths. A previously validated modelling approach identifies the protein binding pocket involved in the interaction with C60. Computational predictions, combined with experimental investigations, provide powerful tools to design tailor-made C60@proteins bioconjugates for specific applications. Bioconjugation ; Fullerene ; Chemistry ; Nanomedicine ; Nanotechnology ; Non-covalent interactions ; Aqueous solution ; Ionic bonding ; Nanoparticle ; Materials science ; Organic chemistry ; Hydrogen bond ; Molecule Fullerene Chemistry and Applications ; Molecular Junctions and Nanostructures ; Diamond and Carbon-based Materials Research
Authors: Laura Alcázar | Paul V. Bernhardt | Montserrat Ferrer | Mercè Font-Bardı́a | Albert Gallén | Jesús Jover | Manuel Martı́nez | Jack S. Peters | Timothy J. Zerk
Source: Inorganic Chemistry (article, 2018-07-03)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Kineticomechanistic Study of the Redox pH Cycling Processes Occurring on a Robust Water-Soluble Cyanido-Bridged Mixed-Valence {Co<sup>III</sup>/Fe<sup>II</sup>}<sub>2</sub> Square A kineticomechanistic study of reversible electron-transfer processes undergone by the water-soluble, cyanido-bridged mixed-valence [{Co<sup>III</sup>{(Me)<sub>2</sub>(μ-ET)cyclen}}<sub>2</sub>{(μ-NC)<sub>2</sub>Fe<sup>II</sup>(CN)<sub>4</sub>}<sub>2</sub>]<sup>2-</sup> square has been carried out. The oxidation reaction consists of a two-step process with the participation of a solvent-assisted outer-sphere complex, as a result of the establishment of hydrogen bonds that involve the oxo groups of the oxidant (peroxodisulfate) and the terminal cyanido ligands of the tetrametallic square. The formally endergonic reduction reaction of the fully oxidized ([{Co<sup>III</sup>{(Me)<sub>2</sub>(μ-ET)cyclen}}<sub>2</sub>{(μ-NC)<sub>2</sub>Fe<sup>III</sup>(CN)<sub>4</sub>}<sub>2</sub>]) core by water, producing hydrogen peroxide from water even at low pH values, is also a two-step process. Each one of these processes requires a set of two preequilibria involving the association of OH<sup>-</sup> and its subsequent deprotonation by a further OH<sup>-</sup> anion. The structure of the square compound in its fully protonated form has also been determined by X-ray diffraction and shows the existence of strong hydrogen-bonding interactions, in agreement with the rather high basicity of the terminal cyanido ligands. Likewise, density functional theory calculations on the tetrametallic complex showed zones with negative electrostatic potential around the Fe<sup>II</sup> centers of the square that would account for the establishment of the hydrogen bonds found in the solid state. Spectroelectrochemistry experiments demonstrated the singular stability of the {Co<sup>III</sup>/Fe<sup>II</sup>}<sub>2</sub><sup>2-</sup> complex, as well as that of their partially, {Co<sub>2</sub><sup>III</sup>/Fe<sup>III</sup>Fe<sup>II</sup>}<sup>-</sup>, and fully, {Co<sup>III</sup>/Fe<sup>III</sup>}<sub>2</sub>, oxidized counterparts because no hysteresis was observed in these measurements. Chemistry ; Valence (chemistry) ; Redox ; Inorganic chemistry ; Analytical Chemistry (journal) ; Environmental chemistry ; Organic chemistry Magnetism in coordination complexes ; Porphyrin and Phthalocyanine Chemistry ; Spectroscopy and Quantum Chemical Studies
Authors: Sergio D’Addato | María Chiara Spadaro
Source: Physica Scripta (article, 2018-01-11)
Field: Materials Science — Materials Chemistry

Low pressure bottom-up synthesis of metal@oxide and oxide nanoparticles: control of structure and functional properties The experimental activity on core@shell, metal@oxide and oxide nanoparticles (NP) grown with physical synthesis, and more specifically by low pressure gas aggregation sources (LPGAS) is reviewed, through a selection of examples encompassing some potential application in nanotechnology. After an introduction on applications of NP, a brief description of the main characteristics of the growth process of clusters and NP in the LPGAS is given. Successively, some relevant case studies are reported: Oxide ; Nanoparticle ; Materials science ; Nanotechnology ; Metal ; Shell (structure) ; Chemical engineering ; Metallurgy ; Composite material Quantum Dots Synthesis And Properties ; Copper-based nanomaterials and applications ; ZnO doping and properties
Authors: Molly M. H. Sung | Sofia Jdanova | Robert H. Morris
Source: Journal of Organometallic Chemistry (article, 2018-10-29)
Field: Chemistry — Organic Chemistry

Ligand acidity constants as calculated by density functional theory for PF3 and N-Heterocyclic carbene ligands in hydride complexes of Iron(II) Chemistry ; Deprotonation ; Hydride ; Carbene ; Ligand (biochemistry) ; Density functional theory ; Acid dissociation constant ; Dissociation (chemistry) ; Metal ; Catalysis ; Proton affinity ; Computational chemistry ; Crystallography ; Medicinal chemistry ; Inorganic chemistry ; Physical chemistry ; Stereochemistry ; Organic chemistry ; Protonation ; Ion N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Asymmetric Hydrogenation and Catalysis ; Carbon dioxide utilization in catalysis
Authors: Jeroen Stryckers | Tom Swusten | Ward Brullot | Jan D’Haen | Thierry Verbiest | Wim Deferme
Source: Advanced Engineering Materials (article, 2018-10-08)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Ultrasonic Spray Coating as a Fast Alternative Technique for the Deposition of Hybrid Magnetic‐Plasmonic Nanocomposites Advanced applications in optics, for example, Faraday isolators, demand for complex magneto‐plasmonic nanostructures which exhibit large Faraday rotation. These structures is fabricated by a Layer‐by‐Layer approach, albeit this being a slow technique. Here, the ultrasonic spray coating as a promising alternative method toward the formation of hybrid magneto‐plasmonic structures is pioneered by the authors. Ultrasonic spray coating is a stable, fast, and tunable mass production method applied in this work to deposit gold and iron oxide nanoparticles. Altering multiple deposition parameters give the spray coating technique a large amount of control over the coverage. Optical and magneto‐optical properties, layer formation and surface coverage of single and hybrid layers with increasing thickness and number of layers are studied and compared to samples synthesized by Layer‐by‐Layer deposition. Ultrasonic spray coating paves the way to the widespread application of innovative and versatile hybrid magnetic‐plasmonic nanocomposites. Materials science ; Coating ; Layer (electronics) ; Faraday effect ; Ultrasonic sensor ; Deposition (geology) ; Nanocomposite ; Plasmon ; Nanotechnology ; Optoelectronics ; Nanoparticle ; Plasmonic nanoparticles ; Magnetic field Gold and Silver Nanoparticles Synthesis and Applications ; Laser-Ablation Synthesis of Nanoparticles ; Plasmonic and Surface Plasmon Research
Authors: Aleksander Zubelewicz
Source: Scientific Reports (article, 2018-03-26)
Field: Materials Science — Materials Chemistry

Metal behavior in the extremes of dynamics When the rate of loading is faster than the rate at which material absorbs and converts energy to plastic work and damages, then there is an excess of energy that is partly stored in the material's microstructure and the rest of it triggers micro-dynamic excitations. The additional storage necessitates the development of plastic flow constraints and is directly responsible for the observed dynamic strengthening. At extreme conditions, we find that the micro-excitations contribute to the dynamic behavior. The phenomena are universally observed in metals, frictional materials and polymers. In essence, strong dynamics creates conditions at which materials are pushed from equilibrium and temporarily reside in an excited state of behavior. This study is focused on the behavior of metals. The concept is incorporated into a mechanisms-based constitutive model and is examined for annealed OFHC copper. Materials science ; Work (physics) ; Microstructure ; Polymer ; Stored energy ; Dynamics (music) ; Excited state ; Metal ; Copper ; Plasticity ; Composite material ; Mechanics ; Chemical physics ; Thermodynamics ; Metallurgy ; Chemistry ; Physics High-Velocity Impact and Material Behavior ; Structural Response to Dynamic Loads ; Microstructure and mechanical properties
Authors: Roman Gozdur | P. Gębara | Krzysztof Chwastek
Source: Open Physics (article, 2018-05-24)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Modeling hysteresis curves of La(FeCoSi)13 compound near the transition point with the GRUCAD model Abstract The paper presents a new approach to modeling of magnetic properties and the influence of temperature on hysteresis loops in La(FeCoSi) 13 magnetocaloric compound. The GRUCAD hysteresis model has been used for analysis of magnetic behavior in the vicinity of the magnetic phase transition. The modeling results are in a qualitative agreement with experiment. Hysteresis ; Magnetic refrigeration ; Magnetic hysteresis ; Condensed matter physics ; Materials science ; Phase transition ; Thermodynamics ; Magnetic field ; Physics ; Magnetization Magnetic and transport properties of perovskites and related materials ; Magnetic Properties and Applications ; Magnetic Properties of Alloys
Authors: Odysseas Tsilipakos | F. Liu | A. Pitilakis | Anna C. Tasolamprou | Do‐Hoon Kwon | M. S. Mirmoosa | Nikolaos V. Kantartzis | E. N. Economou | Maria Kafesaki | Costas M. Soukoulis | Sergei Tretyakov
Source: 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) (preprint, 2018-08-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Tunable Perfect Anomalous Reflection in Metasurfaces with Capacitive Lumped Elements We demonstrate tunable perfect anomalous reflection with metasurfaces incorporating lumped elements. The tunable capacitance of each element provides continuous control over the local surface reactance, allowing for controlling the evanescent field distribution and efficiently tilting the reflected wavefront away from the specular direction. The performance of the metasurface is evaluated for both TE and TM polarization and for reflection to the first and second diffraction order. Specular reflection ; Reactance ; Optics ; Capacitive sensing ; Reflection (computer programming) ; Capacitance ; Wavefront ; Polarization (electrochemistry) ; Diffraction ; Cloaking ; Materials science ; Physics ; Optoelectronics ; Metamaterial ; Computer science ; Voltage ; Engineering ; Electrical engineering Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis
Authors: Eneko Larrañeta
Source: Journal of Chemical Education (article, 2018-08-22)
Field: Chemistry — Physical and Theoretical Chemistry

Incorporating Stories of Sedatives, Spoiled Sweet Clover Hay, and Plants from the Amazon Rainforest into a Pharmaceutical Chemistry Course To Engage Students and Introduce Drug Design Strategies This article describes three historical cases of drug discovery and how they were adapted as examples to teach chemical analysis to students pursuing a pharmacy (UK MPharm) and pharmaceutical sciences (BSc Pharmaceutical Sciences) degree. The selected cases were the synthesis of benzodiazepines and the discovery of warfarin and neuromuscular blocking agents. These examples present some peculiarities as they were developed in special circumstances and without the assistance of modern chemical analysis techniques. By incorporating these examples in a pharmaceutical chemistry class, the students became aware of the importance of chemical knowledge in overcoming technical limitations. Moreover, the examples were designed to stimulate the interest of the students in the subject. Three case studies including drug discovery examples were implemented in a chemistry module delivered to pharmacy students. The views of the students (48 MPharm and 7 BSc pharmaceutical sciences) about these lectures was obtained by using a questionnaire. After delivering the lectures, the majority of the students (64%) thought that understanding the history behind some scientific discoveries was important for them. Additionally, they considered that the selected historical examples were not only interesting but useful to understand the material delivered in the pharmaceutical chemistry module (75% of the students). Pharmacy ; Pharmaceutical sciences ; Class (philosophy) ; Chemistry ; Drug discovery ; Psychology ; Medicine ; Pharmacology ; Computer science Various Chemistry Research Topics ; Chemistry and Chemical Engineering ; Innovative Teaching Methods
Authors: Garrett B. Goh | Charles Siegel | Abhinav Vishnu | Nathan O. Hodas | Nathan Baker
Source:  (preprint, 2018-03-01)
Field: Materials Science — Materials Chemistry

How Much Chemistry Does a Deep Neural Network Need to Know to Make Accurate Predictions? The meteoric rise of deep learning models in computer vision research, having achieved human-level accuracy in image recognition tasks is firm evidence of the impact of representation learning of deep neural networks. In the chemistry domain, recent advances have also led to the development of similar CNN models, such as Chemception, that is trained to predict chemical properties using images of molecular drawings. In this work, we investigate the effects of systematically removing and adding localized domain-specific information to the image channels of the training data. By augmenting images with only 3 additional basic information, and without introducing any architectural changes, we demonstrate that an augmented Chemception (AugChemception) outperforms the original model in the prediction of toxicity, activity, and solvation free energy. Then, by altering the information content in the images, and examining the resulting model's performance, we also identify two distinct learning patterns in predicting toxicity/activity as compared to solvation free energy. These patterns suggest that Chemception is learning about its tasks in the manner that is consistent with established knowledge. Thus, our work demonstrates that advanced chemical knowledge is not a pre-requisite for deep learning models to accurately predict complex chemical properties. Deep learning ; Computer science ; Artificial intelligence ; Domain (mathematical analysis) ; Representation (politics) ; Solvation ; Artificial neural network ; Machine learning ; Domain knowledge ; Deep neural networks ; Image (mathematics) ; Chemistry Machine Learning in Materials Science ; Computational Drug Discovery Methods ; Metabolomics and Mass Spectrometry Studies
Authors: M.E. Medhat
Source: Radiation effects and defects in solids (article, 2018-11-28)
Field: Materials Science — Materials Chemistry

Application of neural network for predicting photon attenuation through materials Photon attenuation prediction in composite materials usually requires a great expert knowledge and time-consuming calculations with complex procedures especially in experimental arrangements. An artificial neural network can be applied to predict exactly the value of mass attenuation at different energies. For training of the network a neural model was designed with chemical composition and molecular cross-section of samples as neural input, while the photon attenuation coefficient was its output. The method was applied for different composite materials with different chemical compositions. The results of mass attenuation coefficients were compared with the experimental and theoretical data for the same samples and a good agreement has been observed. The results indicate that this process can be followed to determine the data on the attenuation of gamma-rays with the several energies in different materials. Attenuation ; Artificial neural network ; Attenuation coefficient ; Photon ; Mass attenuation coefficient ; Biological system ; Materials science ; Computational physics ; Computer science ; Optics ; Physics ; Artificial intelligence Radiation Shielding Materials Analysis ; Advanced X-ray and CT Imaging ; X-ray Diffraction in Crystallography