jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Joseph J. Shaffer | Merry Mani | Samantha Schmitz | Jia Xu | Nana Owusu | Dee Wu | Vincent A. Magnotta | John A. Wemmie
Source: Frontiers in Psychiatry (review, 2020-09-24)
Field: Materials Science — Materials Chemistry

Proton Exchange Magnetic Resonance Imaging: Current and Future Applications in Psychiatric Research Proton exchange provides a powerful contrast mechanism for magnetic resonance imaging (MRI). MRI techniques sensitive to proton exchange provide new opportunities to map, with high spatial and temporal resolution, compounds important for brain metabolism and function. Two such techniques, chemical exchange saturation transfer (CEST) and T1 relaxation in the rotating frame (T1ρ), are emerging as promising tools in the study of neurological and psychiatric illnesses to study brain metabolism. This review describes proton exchange for non-experts, highlights the current status of proton-exchange MRI, and presents advantages and drawbacks of these techniques compared to more traditional methods of imaging brain metabolism, including positron emission tomography (PET) and MR spectroscopy (MRS). Finally, this review highlights new frontiers for the use of CEST and T1ρ in brain research. Positron emission tomography ; Functional magnetic resonance spectroscopy of the brain ; Magnetic resonance imaging ; Nuclear magnetic resonance ; Neuroimaging ; Proton magnetic resonance ; Brain function ; Neuroscience ; Medicine ; Physics ; Psychology ; Radiology Lanthanide and Transition Metal Complexes ; Advanced MRI Techniques and Applications ; Electron Spin Resonance Studies
Authors: Lalit Mohan Kandpal | Jayoung Lee | Hyungjin Bae | Moon S. Kim | Insuck Baek | Byoung–Kwan Cho
Source: Sensors (article, 2020-01-03)
Field: Chemistry — Analytical Chemistry

Near-Infrared Transmittance Spectral Imaging for Nondestructive Measurement of Internal Disorder in Korean Ginseng The grading of ginseng (Panax ginseng) including the evaluation of internal quality attributes is essential in the ginseng industry for quality control. Assessment for inner whitening, a major internal disorder, must be conducted when identifying high quality ginseng. Conventional methods for detecting inner whitening in ginseng root samples use manual inspection, which is time-consuming and inaccurate. This study develops an internal quality measurement technique using near-infrared transmittance spectral imaging to evaluate inner whitening in ginseng samples. Principle component analysis (PCA) was used on ginseng hypercube data to evaluate the developed technique. The transmittance spectra and spectral images of ginseng samples exhibiting inner whitening showed weak intensity characteristics compared to normal ginseng in the region of 900-1050 nm and 1150-1400 nm respectively, owing to the presence of whitish internal tissues that have higher optical density. On the basis of the multivariate analysis method, even a simple waveband ratio image has the great potential to quickly detect inner whitening in ginseng samples, since these ratio images show a significant difference between whitened and non-whitened regions. Therefore, it is possible to develop an efficient and rapid spectral imaging system for the real-time detection of inner whitening in ginseng using minimal spectral wavebands. This novel strategy for the rapid, cost-effective, non-destructive detection of ginseng's inner quality can be a key component for the automation of ginseng grading. Ginseng ; Near-infrared spectroscopy ; Materials science ; Biomedical engineering ; Computer science ; Biological system ; Artificial intelligence ; Optics ; Chemistry ; Medicine ; Physics ; Biology Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Food Quality and Safety Studies
Authors: Patricia Sanmartín | Michela Gambino | Elsa Fuentes | Miguel Serrano
Source: Sensors (article, 2020-04-20)
Field: Chemistry — Analytical Chemistry

A Simple, Reliable, and Inexpensive Solution for Contact Color Measurement in Small Plant Samples Correct color measurement by contact-type color measuring devices requires that the sample surface fully covers the head of the device, so their use on small samples remains a challenge. Here, we propose to use cardboard adaptors on the two aperture masks (3 and 8 mm diameter measuring area) of a broadly used portable spectrophotometer. Adaptors in black and white to reduce the measuring area by 50% and 70% were applied in this study. Representatives of the family Campanulaceae have been used to test the methodology, given the occurrence of small leaves. Our results show that, following colorimetric criteria, the only setting providing indistinguishable colors according to the perception of the human eye is the use of a 50%-reducing adaptor on the 3-mm aperture. In addition, statistical analysis suggests the use of the white adaptor. Our contribution offers a sound measurement technique to gather ecological information from the color of leaves, petals, and other small samples. Aperture (computer memory) ; Computer science ; Artificial intelligence ; Computer vision ; Sample (material) ; Optics ; Engineering ; Chemistry ; Physics ; Mechanical engineering Spectroscopy and Chemometric Analyses ; Leaf Properties and Growth Measurement ; Advanced Chemical Sensor Technologies
Authors: T. E. G. Alvarez-Arenas | Domingo Sancho‐Knapik | José Javier Peguero‐Pina | Eustaquio Gil‐Pelegrín
Source: Frontiers in Plant Science (article, 2020-05-29)
Field: Chemistry — Analytical Chemistry

Surface Density of the Spongy and Palisade Parenchyma Layers of Leaves Extracted From Wideband Ultrasonic Resonance Spectra The wide band and air-coupled ultrasonic resonant spectroscopy together with a modified Simulated Annealing metaheuristic algorithm and a 1D layered acoustic-model are used to resolve the structure of plant leaves. In particular, this paper focuses on the extraction of the surface density of the different layers of tissue in leaves having a relatively simple structure. There are three main reasons to select the surface density as the focus of this study: (i) it is a parameter directly extracted by the proposed technique and it requires no further processing, (ii) it is relevant in order to study the dynamic of the water within the different tissues of the leaves and also to study the differential development of the different tissues, and (iii) unlike other parameters provided by this technique (like resonant frequency, impedance, ultrasonic elastic modulus, or ultrasonic damping), this parameter can be easier to understand as it is a direct measure of mass per unit surface. The selection of leaves with a simple structure is justified by the convenience of avoiding an unnecessary complication of the data extraction step. In this work, the technique was applied to determine the surface density of the palisade and spongy parenchyma layers of tissue of <i>Ligustrum lucidum</i>, <i>Vitis vinifera</i>, and <i>Viburnum tinus</i> leaves. The first species was used to study the variation of the surface density at full turgor with the thickness of the leaf, while the two other species were used to study the variation of the surface densities with the variation in the leaf relative water content. Consistency of the results with other conventional measurements (like overall surface density, and cross-section optical and cryo-SEM images) is discussed. The results obtained reveal the potential of this technique; moreover, the technique presents the additional advantage that can be applied <i>in-vivo</i> as it is completely non-invasive, non-destructive, fast, and equipment required is portable. Ultrasonic sensor ; Biological system ; Materials science ; Turgor pressure ; Acoustic impedance ; Acoustics ; Botany ; Physics ; Biology Spectroscopy and Chemometric Analyses ; Leaf Properties and Growth Measurement ; Plant Surface Properties and Treatments
Authors: Hiroshi Tsukahara | Kaoru Iwano | T. Ishikawa | Chiharu Mitsumata | Kanta Ono
Source: NPG Asia Materials (article, 2020-04-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Relationship between magnetic nucleation and the microstructure of a hot-deformed permanent magnet: micromagnetic simulation Abstract The grains initiating magnetization reversal in the microstructure of a hot-deformed permanent magnet have been identified in this study by performing micromagnetic simulations based on the Landau–Lifshitz–Gilbert equation. Hot-deformed permanent magnets comprise tabular grains, the easy-axis orientations of which are inclined with respect to the nominal easy axis of the permanent magnet. In the simulation model, the grains complexly overlap, similar to in actual permanent magnets. We analyze the simulation results considering grain overlap and the easy-axis tilt angles of the grains. The initiation of magnetic nucleation requires a high concentration of grains with large easy-axis tilt angles. We clarify the magnetic-nucleation process and provide a method to enhance the performance of permanent magnets by avoiding a high concentration of grains with large easy-axis tilt angles. Magnet ; Nucleation ; Materials science ; Microstructure ; Tilt (camera) ; Condensed matter physics ; Micromagnetics ; Magnetization ; Magnetic field ; Composite material ; Mechanical engineering ; Physics ; Thermodynamics Magnetic Properties of Alloys ; Magnetic properties of thin films ; Magnetic and transport properties of perovskites and related materials
Authors: John Bradshaw | Brooks Paige | Matt J. Kusner | Marwin Segler | José Miguel Hernández-Lobato
Source:  (preprint, 2020-12-21)
Field: Materials Science — Materials Chemistry

Barking up the right tree: an approach to search over molecule synthesis DAGs When designing new molecules with particular properties, it is not only important what to make but crucially how to make it. These instructions form a synthesis directed acyclic graph (DAG), describing how a large vocabulary of simple building blocks can be recursively combined through chemical reactions to create more complicated molecules of interest. In contrast, many current deep generative models for molecules ignore synthesizability. We therefore propose a deep generative model that better represents the real world process, by directly outputting molecule synthesis DAGs. We argue that this provides sensible inductive biases, ensuring that our model searches over the same chemical space that chemists would also have access to, as well as interpretability. We show that our approach is able to model chemical space well, producing a wide range of diverse molecules, and allows for unconstrained optimization of an inherently constrained problem: maximize certain chemical properties such that discovered molecules are synthesizable. Chemical space ; Directed acyclic graph ; Computer science ; Interpretability ; Tree (set theory) ; Simple (philosophy) ; Theoretical computer science ; Generative model ; Vocabulary ; Generative grammar ; Artificial intelligence ; Algorithm ; Chemistry ; Drug discovery ; Mathematics Machine Learning in Materials Science ; Computational Drug Discovery Methods ; Protein Structure and Dynamics
Authors: Giovanni Gomes Guerreiro | Fabrício V. de Andrade | Márcio Roberto de Freitas
Source: Ceramics International (article, 2020-08-26)
Field: Materials Science — Materials Chemistry

Carbon nanostructures based-adsorbent obtained from iron ore tailings Adsorption ; Materials science ; Amorphous carbon ; Chemical engineering ; Langmuir adsorption model ; Carbon fibers ; Cationic polymerization ; Amorphous solid ; Organic chemistry ; Chemistry ; Composite material ; Polymer chemistry ; Composite number Graphene research and applications ; Adsorption and biosorption for pollutant removal ; Graphene and Nanomaterials Applications
Authors: Vladimir V. Botvin | Svetlana Karaseva | В. В. Хасанов | A. G. Filimoshkin
Source: Polymers (article, 2020-10-17)
Field: Materials Science — Biomaterials

Kinetic Study of Depolymerization of Lactic and Glycolic Acid Oligomers in the Presence of Oxide Catalysts For glycolic acid oligomers (GAO): l-lactic acid oligomers (LAO) mixtures, as an example, it was shown that the nature of the active sites of the catalysts significantly affect the depolymerization process. So, ZnO, which has mainly basic sites, leads to the highest yield of cyclic diesters. On the contrary, depolymerization in the presence of acidic γ-Al<sub>2</sub>O<sub>3</sub> and without a catalyst is characterized by lower diester yields due to the prevalence of a side polycondensation reaction. Using GAO:LAO mixtures, it was shown that in the case of three studied systems (with ZnO, γ-Al<sub>2</sub>O<sub>3</sub>, and without catalyst), mixed interactions occurred, including <i>homo</i>-paired and <i>hetero</i>-paired intermolecular interactions, as well as intramolecular interactions of oligomeric molecules. Kinetic models of the processes under study were determined by isoconversional thermal analysis. In the case of depolymerization of oligomers in the presence of ZnO, the kinetic model was between the kinetic models of the first (F1) and second (F2) orders, while in depolymerization in the presence of γ-Al<sub>2</sub>O<sub>3</sub> and without a catalyst, the process was described by diffusion models such as the Jander equation (D3) and Zhuravlev, Lesokin, Tempelman equation (D5). Depolymerization ; Glycolic acid ; Catalysis ; Chemistry ; Polymerization ; Intramolecular force ; Polymer chemistry ; Lactic acid ; Yield (engineering) ; Condensation polymer ; Materials science ; Polymer ; Organic chemistry biodegradable polymer synthesis and properties ; Carbon dioxide utilization in catalysis ; Thermal and Kinetic Analysis
Authors: Omirserik Baigenzhenov | А.Т. Khabiyev | Brajendra Mishra | M. Deniz Turan | М.С. Акбаров | Т.А. Чепуштанова
Source: Minerals (article, 2020-07-31)
Field: Chemistry — Inorganic Chemistry

Uranium (VI) Recovery from Black Shale Leaching Solutions Using Ion Exchange: Kinetics and Equilibrium Studies This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact time at room temperature. These experiments addressed sorption kinetics and sorption isotherm. The maximum sorption capacity reached 55.8 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at initial uranium concentration of 0.62 mg·L−1. To describe sorption kinetics pseudo-first-order, pseudo-second-order and intraparticle diffusion models were proposed. Studies indicated that the sorption of uranium can be fitted by a pseudo-second-order kinetic model very well. Equilibria were described by Langmuir, Freundlich, and Dubinin–Radushkevich equations. The experimental sorption isotherm is successfully described by the Langmuir model. Sorption ; Uranium ; Kinetics ; Langmuir ; Chemistry ; Freundlich equation ; Leaching (pedology) ; Oil shale ; Ion exchange ; Diffusion ; Langmuir adsorption model ; Inorganic chemistry ; Nuclear chemistry ; Thermodynamics ; Ion ; Adsorption ; Materials science ; Geology ; Physical chemistry ; Organic chemistry ; Soil water ; Metallurgy ; Soil science Radioactive element chemistry and processing ; Extraction and Separation Processes ; Adsorption and biosorption for pollutant removal
Authors: W. A. Monika Madhavi | Samantha Weerasinghe | Konstantin I. Momot
Source: Journal of Molecular Liquids (article, 2020-11-09)
Field: Chemistry — Spectroscopy

Reorientational dynamics of molecules in liquid methane: A molecular dynamics simulation study Rotational diffusion ; Legendre polynomials ; Chemistry ; Relaxation (psychology) ; Diffusion ; Rotation around a fixed axis ; Molecular dynamics ; Molecule ; Chemical physics ; Molecular physics ; Rotational dynamics ; Thermodynamics ; Computational chemistry ; Classical mechanics ; Physics ; Quantum mechanics ; Organic chemistry Advanced NMR Techniques and Applications ; NMR spectroscopy and applications ; Molecular spectroscopy and chirality
Authors: Ali Boukhemkhem | Alejandro Herrero Pizarro | Carmen B. Molina
Source: Clay Minerals (article, 2020-06-01)
Field: Materials Science — Biomaterials

Enhancement of the adsorption properties of two natural bentonites by ion exchange: equilibrium, kinetics and thermodynamic study ABSTRACT In this investigation, Maghnia (Ma) and Mostaganem (Ms) bentonite clays, mined from west Algeria, with no prior affinity for anionic dyes, were modified by simple ion exchange with aqueous Fe 3+ solutions, followed by calcination at 500°C. The resulting materials, Fe-Ma and Fe-Ms, respectively, were employed as adsorbents for methyl orange. The starting materials and the two adsorbents were characterized by X-ray diffraction, N 2 adsorption–desorption isotherms, Brunauer–Emmett–Teller specific surface area and X-ray fluorescence and by determining the point of zero charge. The effects of various variables, such as initial dye concentration, contact time, adsorbent dose, initial pH and adsorption temperature, were studied. The kinetics were well described by the pseudo-second-order model and the mechanism was determined from the intraparticle diffusion model, while corresponding isotherms fitted better to the Freundlich model. Thermodynamic parameters showed that the adsorption process was endothermic, spontaneous and physical in nature, accompanied by an increase of entropy. Adsorption ; Endothermic process ; Chemistry ; Freundlich equation ; Bentonite ; Kinetics ; Desorption ; Ion exchange ; Aqueous solution ; Thermodynamics ; Mass action law ; Ion ; Chemical engineering ; Physical chemistry ; Organic chemistry Clay minerals and soil interactions ; Adsorption and biosorption for pollutant removal ; Iron oxide chemistry and applications
Authors: Xinyao Wang | Jian Liu
Source: ChemNanoMat (article, 2020-06-17)
Field: Chemistry — Organic Chemistry

Functional Micro/Nanoreactors for Nanospace‐Confined Migrations and Diffusions Abstract Diffusion is a natural phenomenon and essential in many fields. Conceptually, diffusion in solid materials, especially in the confined micro/nano‐spaces, can boost the development of new functional nanomaterials for applications across a range of areas. In this Minireview, we categorize the diffusion behavior at the nanoscale including atom/ion diffusion and direct migration of nanoparticles, and discuss how these two strategies can be applied for the construction of nanoreactors with unique structures and components. The understanding of diffusion principles in a confined system is summarized in detail. Moreover, the development opportunities of diffusion process in future research are outlined. Nanoreactor ; Nanotechnology ; Diffusion ; Materials science ; Computer science ; Nanoparticle ; Physics Nanomaterials for catalytic reactions ; Electrocatalysts for Energy Conversion ; Copper-based nanomaterials and applications
Authors: Yalin Cheng | Kaiqian Wang | Biyang Tu | Shan Xue | Jiahui Deng | Haisheng Tao
Source: RSC Advances (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Adsorption of divalent cadmium by calcified iron-embedded carbon beads A novel iron-embedded carbon bead was prepared by the calcination of a calcium alginate gel bead mixed with iron nanoparticles coated by polydopamine. The prepared iron-embedded carbon bead was characterized by infrared spectrum analysis, X-ray diffraction, Raman spectroscopy, vibrating sample magnetometry, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. It was discovered that the novel structure efficaciously prevented the agglomeration of iron nanoparticles. Additionally, the effects of dose, pH, exposure time, temperature and initial concentration on the adsorption of Cd(ii) were studied, and the reusability of the material was analyzed. Fe/SA-C showed high Cd(ii) removal capability (220.3, 225.7, 240.8 mg g<sup>-1</sup> at 288, 298, 308 K), easy recoverability and high stability. In addition, some slightly different interpretations of the adsorption mechanism are given. This study clearly revealed that Fe/SA-C has potential application in the removal of Cd(ii). Adsorption ; Raman spectroscopy ; Transmission electron microscopy ; Scanning electron microscope ; X-ray photoelectron spectroscopy ; Calcination ; Chemistry ; Nuclear chemistry ; Nanoparticle ; Cadmium ; Carbon fibers ; Infrared spectroscopy ; Chemical engineering ; Materials science ; Nanotechnology ; Catalysis ; Physical chemistry ; Composite number ; Organic chemistry Nanomaterials for catalytic reactions ; Adsorption and biosorption for pollutant removal ; Graphene and Nanomaterials Applications
Authors: Giana Almeida | Sandra Domenek | Patrick Perré
Source: Polymer (article, 2020-02-07)
Field: Materials Science — Polymers and Plastics

TransPoly: A theoretical model to quantify the dynamics of water transfer through nanostructured polymer films Fick's laws of diffusion ; Mass transfer ; Polymer ; Relaxation (psychology) ; Materials science ; Diffusion ; Thermodynamics ; Constant (computer programming) ; Chemical physics ; Chemistry ; Composite material ; Physics ; Computer science Polymer crystallization and properties ; Polymer Nanocomposites and Properties ; Advanced Cellulose Research Studies
Authors: Ajay Kumar | Uday Maitra
Source: SN Applied Sciences (article, 2020-11-10)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Facile bile salt-induced synthesis of porous MnO2 nanoflowers: applications in dye removal and oxidation Potassium permanganate ; Cationic polymerization ; Adsorption ; Chemistry ; Salt (chemistry) ; Allylic rearrangement ; Inorganic chemistry ; Permanganate ; Oxide ; Porosity ; Catalysis ; Chemical engineering ; Organic chemistry Supercapacitor Materials and Fabrication ; Nanomaterials for catalytic reactions ; Conducting polymers and applications