jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sandro Cid-Ortega | José Alberto Monroy-Rivera
Source: Food Technology and Biotechnology (review, 2018-01-01)
Field: Chemistry — Spectroscopy

Extraction of Kaempferol and Its Glycosides Using Supercritical Fluids from Plant Sources: A Review Research has focused on the study and design of new products containing phytochemicals (polyphenolic acids, flavonoids and anthocyanins, among others) that contribute to a better life quality for consumers, as well as techniques to improve the extraction of these compounds. In this regard, extraction with supercritical fluids (usually CO<sub>2</sub>) is a technology that has better advantages than organic solvents, since lower temperatures that are used do not damage the product, and is more effective at high pressures. Extracts from plant sources contain significant concentrations of flavonols, one of the main compounds being kaempferol. Research has proven the antioxidant, anticarcinogenic, antidiabetic, cardioprotective, neuroprotective and antimicrobial properties of kaempferol and its glycosides. This review aims to present the main functional properties and extraction with supercritical fluids of kaempferol and its glycosides, as well as the application of this technology in the food area. Kaempferol ; Supercritical fluid ; Supercritical fluid extraction ; Glycoside ; Extraction (chemistry) ; Chromatography ; Chemistry ; Organic chemistry ; Quercetin Analytical Chemistry and Chromatography ; Phase Equilibria and Thermodynamics ; Chromatography in Natural Products
Authors: Andreea Gheorghe | Martijn A. Tepaske | Stefania Tanase
Source: Inorganic Chemistry Frontiers (article, 2018-01-01)
Field: Chemistry — Inorganic Chemistry

Homochiral metal–organic frameworks as heterogeneous catalysts Homochiral metal–organic frameworks (HMOFs) are attractive materials for asymmetric catalysis because they possess high surface area and uniform active sites. Catalysis ; Metal-organic framework ; Metal ; Materials science ; Heterogeneous catalysis ; Nanotechnology ; Chemistry ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Crystallography and molecular interactions
Authors: Dharmini Mehta | Nathania J. Leong | Victoria M. McLeod | Brian D. Kelly | Rashmi Pathak | David J. Owen | Christopher J. H. Porter | Lisa M. Kaminskas
Source: Molecular Pharmaceutics (article, 2018-08-14)
Field: Materials Science — Polymers and Plastics

Reducing Dendrimer Generation and PEG Chain Length Increases Drug Release and Promotes Anticancer Activity of PEGylated Polylysine Dendrimers Conjugated with Doxorubicin via a Cathepsin-Cleavable Peptide Linker PEGylation typically improves the systemic exposure and tumor biodistribution of polymeric drug delivery systems, but may also restrict enzyme access to peptide-based drug linkers. The impact of dendrimer generation (G4 vs G5) and PEG length (570 vs 1100 Da) on the pharmacokinetics, tumor biodistribution, drug release kinetics, and anticancer activity of a series of PEGylated polylysine dendrimers conjugated with doxorubicin via a cathepsin-B cleavable valine-citrulline linker was therefore investigated in rodents. Although the smallest G4 PEG570 dendrimer showed the most efficient cathepsin-mediated doxorubicin release, systemic exposure and tumor uptake were limited. The largest G5 PEG1100 dendrimer showed good tumor uptake and retention but restricted drug liberation and therefore limited anticancer activity. Superior anticancer activity was achieved using an intermediate sized dendrimer that showed better drug release kinetics, systemic exposure, tumor uptake, and retention. The data suggest that balancing PEG molecular weight and dendrimer size is critical when designing chemotherapeutic dendrimers. Dendrimer ; PEGylation ; Chemistry ; Biodistribution ; Doxorubicin ; PEG ratio ; Linker ; Drug delivery ; Polylysine ; Biophysics ; Pharmacology ; Biochemistry ; Polyethylene glycol ; In vitro ; Organic chemistry ; Medicine ; Biology ; Chemotherapy Dendrimers and Hyperbranched Polymers ; RNA Interference and Gene Delivery ; Advanced biosensing and bioanalysis techniques
Authors: Qian Li | Chün Huang | Liwei Liu | Rui Hu | Junle Qu
Source: Cytometry Part A (review, 2018-09-19)
Field: Materials Science — Materials Chemistry

Enhancing Type I Photochemistry in Photodynamic Therapy Under Near Infrared Light by Using Antennae–Fullerene Complexes Photodynamic therapy (PDT) has been developed as salvage or palliative treatment for a wide range of tumors. The principle underlying this therapy is the generation of reactive oxygen species through two types of photochemical pathways. As compared with the type II pathway, the type I pathway offers a higher oxidizing ability for photosensitive residues such as tryptophan, lower oxygen dependency, and deeper tissue penetration ability. In this review, we focus on the enhancement of the type I pathway in the near infrared (NIR) optical therapeutic window of wavelength 700-1,100 nm by using antennae-fullerene complexes. When photo-induced electron transfer occurs from antennas to fullerene, the pathway switches from type II to type I. Enhancing the type I pathway leads to less oxygen dependency and stronger capacity for tryptophan oxidation. Then, antennae that transfer long-wavelength light (e.g., NIR light) energy to fullerene via photo-induced energy and/or electron transfer have the ability to affect deep-seated tumors. On the basis of theories on photo-induced energy/electron transfer in other fields such as solar cells, here, we summarize the mechanism by which the switch from the type II to type I pathway occurs in antenna-fullerene-based PDT. Fullerene ; Photodynamic therapy ; Photochemistry ; Infrared ; Chemistry ; Optics ; Physics ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Chemical Reactions and Mechanisms ; Photodynamic Therapy Research Studies
Authors: T. Murata | Chiaki Yamada | Ko Furukawa | Yasushi Morita
Source: Communications Chemistry (article, 2018-08-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Mixed valence salts based on carbon-centered neutral radical crystals Abstract Organic neutral radicals have been predicted to exhibit various electronic functions such as electrical conduction. However, most organic neutral radicals are insulators, because they cannot form sufficient intermolecular interactions due to the bulky substituent groups required for stabilization. Here we report that one-dimensional assemblies of carbon-centered neutral π-radicals, namely 4,8,12,trioxotriangulene derivatives, possess effective conducting pathways as a result of strong intermolecular interactions based on two-electron-multicenter bonding. The columns of trioxotriangulene derivatives with weak π-dimerization and uniform π-stacking exhibit semiconducting behaviors, with high conductivities of ~10 −3 S cm −1 as a single component purely organic molecular system. We exploit this general tendency to form one-dimensional assemblies, and the large 25 π-electronic system with a robust condensed polycyclic structure, to obtain mixed-valence salts consisting of neutral radicals and the corresponding anionic species with a higher room-temperature conductivity of 1–125 S cm −1 . Radical ; Stacking ; Intermolecular force ; Substituent ; Valence (chemistry) ; Chemistry ; Chemical physics ; Crystallography ; Computational chemistry ; Photochemistry ; Molecule ; Organic chemistry Organic and Molecular Conductors Research ; Perovskite Materials and Applications ; Synthesis and Properties of Aromatic Compounds
Authors: Yingying Wu | Guangxia Wang | Qiaolian Li | Junfeng Xiang | Hua Jiang | Ying Wang
Source: Nature Communications (article, 2018-05-10)
Field: Chemistry — Organic Chemistry

A multistage rotational speed changing molecular rotor regulated by pH and metal cations Despite having significant applications in building nanomachines, molecular rotors with the rotational speed modulations to multiple stages in a wide range of frequency have not yet been well established. Here, we report the discovery of a stimuli-responsive molecular rotor, the rotational speed of which in the slow-to-fast range could be modulated to at least four stages triggered by acid/base and metal cations. The rotor itself rotates rapidly at ambient or elevated temperature but displays a restricted rotation after deprotonation due to the produced intramolecular electrostatic repulsion. Subsequent addition of Li<sup>+</sup> or Na<sup>+</sup> cations introduces an electrostatic bridge to stabilize the transition state of the deprotonated rotor, thus giving a cation-radius-dependent acceleration of the rotation to render the rotor running at a mid-speed. All the stimuli are highly reversible. Our studies provide a conceptual approach for constructing multistage rotational-speed-changing molecular rotors, and further, the practical nanomachines. Deprotonation ; Rotor (electric) ; Rotational speed ; Intramolecular force ; RADIUS ; Rotation (mathematics) ; Acceleration ; Range (aeronautics) ; Chemical physics ; Materials science ; Chemistry ; Physics ; Computer science ; Classical mechanics ; Stereochemistry ; Ion Supramolecular Chemistry and Complexes ; Molecular Sensors and Ion Detection ; Photoreceptor and optogenetics research
Authors: Janna Kiselar | Mark R. Chance
Source: Annual Review of Biophysics (review, 2018-03-14)
Field: Chemistry — Spectroscopy

High-Resolution Hydroxyl Radical Protein Footprinting: Biophysics Tool for Drug Discovery Hydroxyl radical footprinting (HRF) of proteins with mass spectrometry (MS) is a widespread approach for assessing protein structure. Hydroxyl radicals react with a wide variety of protein side chains, and the ease with which radicals can be generated (by radiolysis or photolysis) has made the approach popular with many laboratories. As some side chains are less reactive and thus cannot be probed, additional specific and nonspecific labeling reagents have been introduced to extend the approach. At the same time, advances in liquid chromatography and MS approaches permit an examination of the labeling of individual residues, transforming the approach to high resolution. Lastly, advances in understanding of the chemistry of the approach have led to the determination of absolute protein topologies from HRF data. Overall, the technology can provide precise and accurate measures of side-chain solvent accessibility in a wide range of interesting and useful contexts for the study of protein structure and dynamics in both academia and industry. Footprinting ; Radical ; Chemistry ; DNA footprinting ; Hydroxyl radical ; Mass spectrometry ; Structural biology ; Radiolysis ; Side chain ; Protein structure ; Photodissociation ; Drug discovery ; Combinatorial chemistry ; Chromatography ; Organic chemistry ; Biochemistry ; DNA ; DNA-binding protein ; Base sequence Mass Spectrometry Techniques and Applications ; Metabolomics and Mass Spectrometry Studies ; Protein Structure and Dynamics
Authors: Alán Aspuru‐Guzik | Kristin Persson
Source: Digital Access to Scholarship at Harvard (DASH) (Harvard University) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Materials Acceleration Platform: Accelerating Advanced Energy Materials Discovery by Integrating High-Throughput Methods and Artificial Intelligence. and catalysts for the conversion, capture, and use of CO 2 .In short, new materials constitute one of the cornerstones for the global transition to a low-carbon future.The process of discovering and developing new materials currently entails considerable time, effort, and expense.Each newly discovered Throughput ; Acceleration ; Computer science ; Artificial life ; Artificial intelligence ; Engineering ; Nanotechnology ; Materials science ; Physics ; Operating system Machine Learning in Materials Science ; Electron and X-Ray Spectroscopy Techniques
Authors: Jong‐Soo Bae | Sung‐Kwun Oh | Witold Pedrycz | Zunwei Fu
Source: Applied Intelligence (article, 2018-10-11)
Field: Chemistry — Analytical Chemistry

Design of fuzzy radial basis function neural network classifier based on information data preprocessing for recycling black plastic wastes: comparative studies of ATR FT-IR and Raman spectroscopy Computer science ; Classifier (UML) ; Artificial intelligence ; Artificial neural network ; Pattern recognition (psychology) ; Fourier transform ; Radial basis function ; Materials science ; Fuzzy logic ; Process engineering ; Mathematics ; Engineering Spectroscopy and Chemometric Analyses ; Computational Drug Discovery Methods ; Rough Sets and Fuzzy Logic
Authors: Vikram Garaniya | Don McWilliam | Laurie Goldsworthy | Mohammadmahdi Ghiji
Source: Fuel (article, 2018-04-22)
Field: Chemistry — Analytical Chemistry

Extensive chemical characterization of a heavy fuel oil Asphaltene ; Chemistry ; Oxidizing agent ; Fraction (chemistry) ; Volatility (finance) ; Elution ; Chemical composition ; Solvent ; Combustion ; Oligomer ; Gel permeation chromatography ; Gravimetric analysis ; Inert gas ; Mass fraction ; Fractionation ; Organic chemistry ; Chromatography Petroleum Processing and Analysis ; Heat transfer and supercritical fluids ; Phase Equilibria and Thermodynamics
Authors: Javier Hernandez | V. H. Romero | Alfredo Escalante | Guillermo Toríz | Orlando J. Rojas | Belkis Sulbarán-Rangel
Source: BioResources (article, 2018-03-27)
Field: Materials Science — Biomaterials

Agave tequilana Bagasse as Source of Cellulose Nanocrystals via Organosolv Treatment Cellulose nanocrystals (CNCs) were isolated from Agave tequilana residues derived from ethanol production. Hemicelluloses and lignin extraction from agave bagasse was carried out via organosolv (ethanol/acetic) digestion followed by conventional sulfuric acid hydrolysis. The ethanol/acetic acid treatment resulted in cellulose yields of approximately 67% after lignin and ash removal. Compared to soda and sodium chlorite treatments with organosolv, the time and chemical load needed for delignification were remarkably reduced. The morphology of the cellulose fiber obtained in the three treatments was between 0.55 and 0.62 mm, with which CNC was obtained in the order of 83 to 195 nm in length. It is noteworthy that the longest cellulose fibers and nanocrystals were obtained from organosolv cellulose. The organosolv treatment led to a high purity cellulose, derived CNCs with a minimum energy consumption and mild chemical usage, and also considered the use of material streams associated with distillation processes. Thus, a viable alternative is suggested for the production of high quality CNC from widely available residual biomass that otherwise poses environmental and health-related risks. Organosolv ; Agave ; Bagasse ; Materials science ; Cellulose ; Chemical engineering ; Pulp and paper industry ; Botany ; Engineering Advanced Cellulose Research Studies ; Biofuel production and bioconversion
Authors: Ewa Ropelewska | Piotr Zapotoczny
Source: European Food Research and Technology (article, 2018-03-16)
Field: Chemistry — Analytical Chemistry

Classification of Fusarium-infected and healthy wheat kernels based on features from hyperspectral images and flatbed scanner images: a comparative analysis Wheat infections caused by fungi of the genus Fusarium decrease yields and have serious economic consequences. The produced mycotoxins have harmful effects on human and animal health. The aim of this study was to develop classification models based on selected textural parameters to distinguish between infected and healthy wheat kernels. The classification accuracy of kernels positioned on the ventral side was determined at 78–100% in the model based on textural parameters from hyperspectral images, and at 95–100% based on images generated by a flatbed scanner. Kernels positioned on the dorsal side were correctly classified in 78–98% based on hyperspectral images, and in 92–100% based on colour images. In the models combining textural parameters from the ventral and dorsal sides of wheat kernels, classification accuracy reached 76–98% in hyperspectral images, and 94–100% in images generated by a flatbed scanner. The imaging technique—flatbed scanner and the ventral side of the kernels provided higher classification accuracy results. The results will contribute to further research aiming to develop models for the determination of fungal chemotypes and/or fungal species based on selected textural features of wheat kernels. Hyperspectral imaging ; Scanner ; Artificial intelligence ; Pattern recognition (psychology) ; Fusarium ; Computer vision ; Mathematics ; Computer science ; Biology ; Botany Spectroscopy and Chemometric Analyses ; Mycotoxins in Agriculture and Food ; Plant Pathogens and Fungal Diseases
Authors: Jaimyun Jung | Jae Ik Yoon | Hyung Keun Park | Jin You Kim | Hyoung Seop Kim
Source: Materials Science and Engineering A (article, 2018-11-23)
Field: Materials Science — Materials Chemistry

Bayesian approach in predicting mechanical properties of materials: Application to dual phase steels Kriging ; Computer science ; Experimental data ; Bayesian probability ; Dual (grammatical number) ; Dual-phase steel ; Uncertainty quantification ; Gaussian process ; Process (computing) ; Property (philosophy) ; Phase (matter) ; Microstructure ; Gaussian ; Machine learning ; Artificial intelligence ; Materials science ; Statistics ; Mathematics Machine Learning in Materials Science ; Hydrogen embrittlement and corrosion behaviors in metals ; High Temperature Alloys and Creep
Authors: Wan Xu | Thierry Ollevier | Freddy Kleitz
Source: ACS Catalysis (article, 2018-01-08)
Field: Materials Science — Materials Chemistry

Iron-Modified Mesoporous Silica as an Efficient Solid Lewis Acid Catalyst for the Mukaiyama Aldol Reaction Fe-MCM-41 and Fe-SBA-15, two different iron-containing mesoporous silicas, were successfully synthesized by a straightforward and versatile method using iron acetylacetonate as a metal precursor. pH adjustment with ammonia during the synthesis was found to be an efficient way to improve the iron content. Physicochemical parameters of the iron-containing mesoporous silicas were obtained by nitrogen physisorption measurements, and the coordination environment of iron elements was validated by UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The surface acidity was tested by using a series of Hammett indicators. To further distinguish the Lewis acid sites on the surface, a pyridine adsorption FT-IR method was implemented. These prepared nanoporous catalysts were screened in the Mukaiyama aldol reaction as a model reaction catalyzed by a Lewis acid. The Lewis acid catalytic activity of the materials was fine-tuned, and the corresponding aldol products were obtained in good yield and selectivity. More importantly, the solid catalysts were very stable and could be reused at least nine times while maintaining the same catalytic activity. Lewis acids and bases ; Catalysis ; Mesoporous material ; Chemistry ; Aldol reaction ; Mesoporous silica ; Pyridine ; Physisorption ; Adsorption ; MCM-41 ; Lewis acid catalysis ; Inorganic chemistry ; X-ray photoelectron spectroscopy ; Nanoporous ; Yield (engineering) ; Organic chemistry ; Chemical engineering ; Materials science Mesoporous Materials and Catalysis ; Polyoxometalates: Synthesis and Applications ; Layered Double Hydroxides Synthesis and Applications
Authors: Simon E. Wawra | Lukas Pflug | Thaseem Thajudeen | Carola Kryschi | Michael Stingl | Wolfgang Peukert
Source: Nature Communications (article, 2018-11-15)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Determination of the two-dimensional distributions of gold nanorods by multiwavelength analytical ultracentrifugation Properties of nanoparticles are influenced by various parameters like size, shape or composition. Comprehensive high throughput characterization techniques are urgently needed to improve synthesis, scale up to production and make way for new applications of multidimensional particulate systems. In this study, we present a method for measuring two-dimensional size distributions of plasmonic nanorods in a single experiment. Analytical ultracentrifuge equipped with a multiwavelength extinction detector is used to record the optical and sedimentation properties of gold nanorods simultaneously. A combination of sedimentation and extinction properties, both depending on diameter and length of the dispersed nanorods, is used to measure two-dimensional distributions of gold nanorod samples. The length, diameter, aspect ratio, volume, surface and cross-sectional distributions can be readily obtained from these results. As the technique can be extended to other non-spherical plasmonic particles and can be used for determining relative amounts of particles of different shapes it provides complete and quantitative insights into particulate systems. Nanorod ; Sedimentation ; Materials science ; Analytical Ultracentrifugation ; Nanotechnology ; Ultracentrifuge ; Extinction (optical mineralogy) ; Biological system ; Chemistry ; Mineralogy ; Chromatography Gold and Silver Nanoparticles Synthesis and Applications ; Electrohydrodynamics and Fluid Dynamics ; Nanoparticle-Based Drug Delivery
Authors: Malte Schüler | Oleg E. Peil | Gernot J. Kraberger | Ronald Pordzik | Martijn Marsman | Georg Kresse | Tim O. Wehling | Markus Aichhorn
Source: Journal of Physics Condensed Matter (article, 2018-10-12)
Field: Materials Science — Materials Chemistry

Charge self-consistent many-body corrections using optimized projected localized orbitals In order for methods combining ab initio density-functional theory and many-body techniques to become routinely used, a flexible, fast, and easy-to-use implementation is crucial. We present an implementation of a general charge self-consistent scheme based on projected localized orbitals in the projector augmented wave framework in the Vienna Ab Initio Simulation Package. We give a detailed description on how the projectors are optimally chosen and how the total energy is calculated. We benchmark our implementation in combination with dynamical mean-field theory: first we study the charge-transfer insulator NiO using a Hartree-Fock approach to solve the many-body Hamiltonian. We address the advantages of the optimized against non-optimized projectors and furthermore find that charge self-consistency decreases the dependence of the spectral function-especially the gap-on the double counting. Second, using continuous-time quantum Monte Carlo we study a monolayer of SrVO<sub>3</sub>, where strong orbital polarization occurs due to the reduced dimensionality. Using total-energy calculation for structure determination, we find that electronic correlations have a non-negligible influence on the position of the apical oxygens, and therefore on the thickness of the single SrVO<sub>3</sub> layer. Ab initio ; Atomic orbital ; Curse of dimensionality ; Hamiltonian (control theory) ; Quantum Monte Carlo ; Hubbard model ; Physics ; Density functional theory ; Ab initio quantum chemistry methods ; Statistical physics ; Molecular physics ; Chemistry ; Monte Carlo method ; Quantum mechanics ; Electron ; Computer science ; Mathematics ; Molecule Electronic and Structural Properties of Oxides ; Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics