jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Juntao Xiong | Rui Lin | Rongbin Bu | Zhen Liu | Zhengang Yang | Lianyi Yu
Source: Sensors (article, 2018-02-26)
Field: Chemistry — Analytical Chemistry

A Micro-Damage Detection Method of Litchi Fruit Using Hyperspectral Imaging Technology The non-destructive testing of litchi fruit is of great significance to the fresh-keeping, storage and transportation of harvested litchis. To achieve quick and accurate micro-damage detection, a non-destructive grading test method for litchi fruits was studied using 400-1000 nm hyperspectral imaging technology. The Huaizhi litchi was chosen in this study, and the hyperspectral data average for the region of interest (ROI) of litchi fruit was extracted for spectral data analysis. Then the hyperspectral data samples of fresh and micro-damaged litchi fruits were selected, and a partial least squares discriminant analysis (PLS-DA) was used to establish a prediction model for the realization of qualitative analysis for litchis with different qualities. For the external validation set, the mean per-type recall and precision were 94.10% and 93.95%, respectively. Principal component analysis (PCA) was used to determine the sensitive wavelength for recognition of litchi quality characteristics, with the results of wavelengths corresponding to the local extremum for the weight coefficient of PC3, i.e., 694, 725 and 798 nm. Then the single-band images corresponding to each sensitive wavelength were analyzed. Finally, the 7-dimension features of the PC3 image were extracted using the Gray Level Co-occurrence Matrix (GLCM). Through image processing, least squares support vector machine (LS-SVM) modeling was conducted to classify the different qualities of litchis. The model was validated using the experiment data, and the average accuracy of the validation set was 93.75%, while the external validation set was 95%. The results indicate the feasibility of using hyperspectral imaging technology in litchi postpartum non-destructive detection and classification. Hyperspectral imaging ; Principal component analysis ; Artificial intelligence ; Pattern recognition (psychology) ; Partial least squares regression ; Support vector machine ; Mathematics ; Linear discriminant analysis ; Computer science ; Least squares support vector machine ; Data set ; Statistics Spectroscopy and Chemometric Analyses ; Essential Oils and Antimicrobial Activity
Authors: Bidisha Samanta | Abir De | Niloy Ganguly | Manuel Gomez-Rodriguez
Source: arXiv (Cornell University) (preprint, 2018-02-14)
Field: Materials Science — Materials Chemistry

Designing Random Graph Models Using Variational Autoencoders With Applications to Chemical Design. Deep generative models have been praised for their ability to learn smooth latent representation of images, text, and audio, which can then be used to generate new, plausible data. However, current generative models are unable to work with graphs due to their unique characteristics--their underlying structure is not Euclidean or grid-like, they remain isomorphic under permutation of the nodes labels, and they come with a different number of nodes and edges. In this paper, we propose a variational autoencoder for graphs, whose encoder and decoder are specially designed to account for the above properties by means of several technical innovations. Moreover, the decoder is able to guarantee a set of local structural and functional properties in the generated graphs. Experiments reveal that our model is able to learn and mimic the generative process of several well-known random graph models and can be used to create new molecules more effectively than several state of the art methods. Autoencoder ; Computer science ; Generative grammar ; Euclidean geometry ; Theoretical computer science ; Generative model ; Representation (politics) ; Grid ; Encoder ; Graph ; Process (computing) ; Random graph ; Structuring ; Set (abstract data type) ; Artificial intelligence ; Algorithm ; Artificial neural network ; Mathematics Machine Learning in Materials Science ; Topic Modeling ; Advanced Graph Neural Networks
Authors: W. Joshua Kennedy | Sarah Izor | Bryan D. Anderson | Geoffrey J. Frank | Vikas Varshney | Gregory J. Ehlert
Source: ACS Applied Materials & Interfaces (article, 2018-11-27)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Thermal Reshaping Dynamics of Gold Nanorods: Influence of Size, Shape, and Local Environment The thermal reshaping of gold nanorods in a polymer matrix is an important phenomenon for many potential applications. However, a fundamental understanding of the various mechanisms that govern the nanorod reshaping dynamics is still lacking. Here, we provide evidence for a phenomenological model of the gold nanorod shape transformation based on the measurements and detailed analysis of the time-resolved thermal reshaping for a variety of gold nanorods having different geometries (aspect ratio, volume, diameter) in a cross-linked epoxy matrix at application relevant temperatures (120-220 °C). Our analysis suggests that (a) the nanorod reshaping dynamics consist of two temporal regimes that are governed by different phenomena and (b) the ultimate amount of reshaping at a given temperature depends strongly on the initial particle geometry and the mechanical stiffness of its surroundings. At short times, the shape transformation is dominated by a curvature-induced surface diffusion process, in which the activation energy for diffusion depends on curvature. At long times, however, the surrounding environment plays a key role in slowing the diffusion and stabilizing the nanorod shape. We show that the long-time behavior can be well described using a modified surface diffusion model that takes into account the slowing of atomic diffusivity as a result of external forces arising from mechanical constraints. The ability to tune both the final shape and the reshaping dynamics in nanocomposites opens up new possibilities in tailoring the optical properties of these materials. Nanorod ; Materials science ; Curvature ; Thermal diffusivity ; Nanotechnology ; Diffusion ; Chemical physics ; Thermal ; Surface diffusion ; Thermodynamics ; Physics ; Chemistry ; Geometry Gold and Silver Nanoparticles Synthesis and Applications ; Nanoparticle-Based Drug Delivery ; Nanomaterials and Printing Technologies
Authors: Jiemei Gao | Yi Lu | Liang Fang | Fang Wu | Faling Ling | Ting Guan | Liuting Shi | Baoshan Hu | Fanming Meng
Source: Environmental Engineering Science (article, 2018-03-29)
Field: Materials Science — Materials Chemistry

Efficient Removal of Methyl Orange and Heavy Metal Ion from Aqueous Solution by NiFe-Cl-Layered Double Hydroxide NiFe-layered double hydroxides (LDHs) with four different interlayer anions (NiFe-X-LDH, X = Cl−, NO3−, SO42−, and CO32−) were synthesized by a coprecipitation method. Their adsorption performance for methyl orange (MO) was first studied. It is found that the interlayer anions strongly affect the adsorption capacity, and adsorption amount of NiFe-X-LDH follows the order CO32−<SO42−<NO3−<Cl−, indicating that NiFe-Cl-LDH possesses the best MO adsorption property. Thus, effects of pH, solution temperature, contact time, and initial MO concentration on MO adsorption behavior of NiFe-Cl-LDH were further investigated systematically. It shows that the adsorbent presents good performance within the pH range of 5 to 6 and the adsorption capacity increases with the solution temperature. Thermodynamic data indicate that adsorption is spontaneous and endothermic. Weber's intraparticle diffusion model reveals that the adsorption includes two processes: external surface adsorption and intraparticle diffusion. Adsorption isotherm data are well fitted with the Langmuir model and the pseudo-second-order model, and the maximum MO adsorption capacity of NiFe-Cl-LDH is 769.23 mg/g, which is larger than some classical LDHs. In addition, the NiFe-Cl-LDH also exhibits high adsorption performance for Cr (VI) (60.24 mg/g) and As (III) (68.49 mg/g). Results show that NiFe-Cl-LDH is a promising material for separation of pollutants from aqueous solutions. Adsorption ; Aqueous solution ; Layered double hydroxides ; Hydroxide ; Coprecipitation ; Methyl orange ; Endothermic process ; Chemistry ; Inorganic chemistry ; Langmuir adsorption model ; Metal ; Metal hydroxide ; Diffusion ; Metal ions in aqueous solution ; Nuclear chemistry ; Organic chemistry ; Catalysis ; Thermodynamics Layered Double Hydroxides Synthesis and Applications ; Adsorption and biosorption for pollutant removal ; Supercapacitor Materials and Fabrication
Authors: Ansar R. Shaikh | Mazahar Farooqui | Rajendra H. Satpute | Syed Abed
Source: Journal of Drug Delivery and Therapeutics (article, 2018-12-21)
Field: Chemistry — Organic Chemistry

Overview on Nitrogen containing compounds and their assessment based on ‘International Regulatory Standards’ Heterocyclic compounds have a role in most fields of sciences such as medicinal chemistry, biochemistry also another area of sciences. More than 90% of new drugscontain heterocycles and the interface between chemistry and biology, at which so much new scientific insight, discovery and application is taking place is crossed by heterocyclic compounds. Compounds derived from heterocyclic rings in pharmacy, medicine, agriculture, plastic, polymer and other fields.Most active heterocycles that have shown considerable biological actions as antifungal, anti-inflammatory, antibacterial, anticonvulsant, antiallergic, herbicidal, anticancer activity. There is always a strong need for new and efficient processes in synthesizing of new Heterocycles.Alum have been used as a novel catalyst in the synthesis of Schiff’s bases. Synthesized Schiff’s bases are free from use of ICH class 1 and Class 2 solvents and also free from structural alerts genotoxic impurities. This review highlights on various aspects of heterocyclic compounds with its biological activity &amp; regulatory assessment based on the ‘International Regulatory Standards’. Keywords: Heterocycles. Nitrogen containing compounds Biological activity, History, Regulatory assessment, International Regulatory Standards Antifungal ; Chemistry ; Combinatorial chemistry ; Organic chemistry ; Biology Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and biological activity
Authors: Hiroko Tokoro | Asuka Namai | Marie Yoshikiyo | Rei Fujiwara | Kouji Chiba | Shin‐ichi Ohkoshi
Source: Scientific Reports (article, 2018-01-02)
Field: Materials Science — Materials Chemistry

Theoretical prediction of a charge-transfer phase transition Phase transition materials are attractive from the viewpoints of basic science as well as practical applications. For example, optical phase transition materials are used for optical recording media. If a phase transition in condensed matter could be predicted or designed prior to synthesizing, the development of phase transition materials will be accelerated. Herein we show a logical strategy for designing a phase transition accompanying a thermal hysteresis loop. Combining first-principles phonon mode calculations and statistical thermodynamic calculations considering cooperative interaction predicts a charge-transfer phase transition between the A-B and A<sup>+</sup>-B<sup>-</sup> phases. As an example, we demonstrate the charge-transfer phase transition on rubidium manganese hexacyanoferrate. The predicted phase transition temperature and the thermal hysteresis loop agree well with the experimental results. This approach will contribute to the rapid development of yet undiscovered phase transition materials. Phase transition ; Ferroics ; Rubidium ; Hysteresis ; Phase (matter) ; Charge (physics) ; Materials science ; Quantum phase transition ; Phonon ; Condensed matter physics ; Thermal ; Chemical physics ; Quantum critical point ; Statistical physics ; Physics ; Thermodynamics ; Quantum mechanics Solid-state spectroscopy and crystallography ; Perovskite Materials and Applications ; Organic and Molecular Conductors Research
Authors: Chi Ching Lau | Mustafa K. Bayazit | Philip James Thomas Reardon | Junwang Tang
Source: The Chemical Record (review, 2018-12-07)
Field: Chemistry — Organic Chemistry

Microwave Intensified Synthesis: Batch and Flow Chemistry Many studies have been conducted on organic and inorganic synthesis by microwave heating owing to its special heating mechanism, leading to improved reaction rate, higher purity and yields. We specifically demonstrated microwave heating in the fabrication of nanoparticles and polyester. By fine-tuning the microwave and experimental parameters, the materials prepared have shown excellent physical and bio-properties, e. g. narrow particle size distribution, controlled morphology, varied molecular structure and so forth. We further highlight the recent procedure of using fluidic reactors on preparing both metals and metal oxides nanoparticles. The experimental design strategies and fundamentals of the microwave interaction with chemicals are presented. Furthermore, the key factors and issues facing in this area are also discussed. Microwave ; Nanotechnology ; Microwave heating ; Fluidics ; Fabrication ; Nanoparticle ; Materials science ; Flow chemistry ; Polyester ; Particle (ecology) ; Continuous flow ; Metal ; Particle size ; Chemical engineering ; Process engineering ; Computer science ; Biochemical engineering ; Metallurgy ; Composite material ; Aerospace engineering ; Engineering Microwave-Assisted Synthesis and Applications ; Nanomaterials for catalytic reactions ; Innovative Microfluidic and Catalytic Techniques Innovation
Authors: Hannes A. Houck | Kevin De Bruycker | Christopher Barner‐Kowollik | Johan M. Winne | Filip Du Prez
Source: Macromolecules (article, 2018-04-11)
Field: Chemistry — Organic Chemistry

Tunable Blocking Agents for Temperature-Controlled Triazolinedione-Based Cross-Linking Reactions The remarkable reactivity of triazolinediones (TADs) toward olefin-type substrates marks them as highly attractive click reagents, in particular for polymer modification and cross-linking. Critically, their ultrafast reaction rates result in handling issues and a rather limited shelf life whereas a particular concern for polymer material applications is homogeneous network formation. Herein, we introduce 2-phenylindoles as highly promising blocking agents for TADs, giving bench-stable reagents at ambient temperature from which the initial TADs can be released upon heating. A set of 11 indoles with varying substitution patterns was synthesized, leading to a precise control for the temperature of deblocking within a broad range of 35–100 °C. The established indole–TAD platform was next applied to bivalent TAD reagents to enable on-demand TAD-based cross-linking reactions of a diene-containing polyurethane (Mn = 12.5 kDa). Fine-tuning of the curing temperatures, down to 50 °C, was evidenced via rheological measurements. Reagent ; Polymer ; Chemistry ; Curing (chemistry) ; Combinatorial chemistry ; Homogeneous ; Chemical engineering ; Polymer chemistry ; Materials science ; Organic chemistry ; Thermodynamics Click Chemistry and Applications ; Catalytic Cross-Coupling Reactions ; Chemical Synthesis and Analysis
Authors: Chun‐Fai Ng | Hak‐Fun Chow | Thomas C. W. Mak
Source: Angewandte Chemie International Edition (article, 2018-03-02)
Field: Materials Science — Biomaterials

Halogen‐Bond‐Mediated Assembly of a Single‐Component Supramolecular Triangle and an Enantiomeric Pair of Double Helices from 2‐(Iodoethynyl)pyridine Derivatives Construction of single-component supramolecular triangle and unprecedented spontaneous resolution of pairs of intertwined supramolecular 3<sub>1</sub> - and 3<sub>2</sub> -double helices by the self-assembly of achiral 2-(iodoethynyl)pyridine and its derivatives have been achieved through intermolecular ethynyl C-I⋅⋅⋅⋅N halogen bonds in the crystalline state. Fine-tuning of the molecular structure of the achiral monomer and choice of solvents for crystallization have a dominant effect on the resultant supramolecular architectures. Supramolecular chemistry ; Halogen bond ; Pyridine ; Intermolecular force ; Monomer ; Crystallography ; Chemistry ; Enantiomer ; Supramolecular assembly ; Crystallization ; Halogen ; Stereochemistry ; Supramolecular chirality ; Double bond ; Single bond ; Hydrogen bond ; Polymer chemistry ; Molecule ; Crystal structure ; Organic chemistry ; Alkyl ; Polymer Supramolecular Self-Assembly in Materials ; Crystallography and molecular interactions ; Supramolecular Chemistry and Complexes
Authors: Yulia D. Gordievskaya | Yury A. Budkov | Elena Yu. Kramarenko
Source: Soft Matter (article, 2018-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

An interplay of electrostatic and excluded volume interactions in the conformational behavior of a dipolar chain: theory and computer simulations The effect of an interplay between electrostatic and excluded volume interactions on the conformational behavior of a dipolar chain has been studied theoretically and by means of molecular dynamics simulations. Every monomer unit of the dipolar chain comprises a dipole formed by a charged group of the chain and an oppositely charged counterion. The counterion is assumed to freely move around the chain but keeping the distance between oppositely charged ions (the dipole length) fixed. The novelty of the developed mean-field theory is that variations of the dipole parameters (the dipole length and the counterion size) have been accounted for in both electrostatic and excluded volume contributions to the total free energy of the dipolar chain. It has been shown that conformational transitions between swollen and collapsed states of the chain can be induced by fine-tuning the balance between electrostatic and excluded volume interactions. In particular, in low-polar media not only globule but also extended coil conformations can be realized even under strong electrostatic attraction. The results of MD simulations of a dipolar chain with variable dipolar length support theoretical conclusions. Dipole ; Counterion ; Chemical physics ; Chemistry ; Electrostatics ; Molecular dynamics ; Chain (unit) ; Ion ; Crystallography ; Computational chemistry ; Physics ; Physical chemistry ; Quantum mechanics ; Organic chemistry Electrostatics and Colloid Interactions ; Dielectric materials and actuators ; Advanced Sensor and Energy Harvesting Materials
Authors: Mark R. Wilson | S.N. Barrientos-Palomo | Phil Stevens | N. L. Mitchell | Gerda Oswald | C. M. Nagaraja | J. P. S. Badyal
Source: ACS Applied Materials & Interfaces (article, 2018-01-22)
Field: Chemistry — Inorganic Chemistry

Substrate-Independent Epitaxial Growth of the Metal–Organic Framework MOF-508a Plasmachemical deposition is a substrate-independent method for the conformal surface functionalization of solid substrates. Structurally well-defined pulsed plasma deposited poly(1-allylimidazole) layers provide surface imidazole linker groups for the directed liquid-phase epitaxial (layer-by-layer) growth of metal-organic frameworks (MOFs) at room temperature. For the case of microporous [Zn (benzene-1,4-dicarboxylate)-(4,4'-bipyridine)<sub>0.5</sub>] (MOF-508), the MOF-508a polymorph containing two interpenetrating crystal lattice frameworks undergoes orientated Volmer-Weber growth and displays CO<sub>2</sub> gas capture behavior at atmospheric concentrations in proportion to the number of epitaxially grown MOF-508 layers. Materials science ; Epitaxy ; Microporous material ; Metal-organic framework ; Chemical engineering ; Imidazole ; Substrate (aquarium) ; Layer (electronics) ; Benzene ; Crystal growth ; Surface modification ; Metal ; Nanotechnology ; Crystallography ; Organic chemistry ; Adsorption ; Composite material ; Metallurgy ; Chemistry Metal-Organic Frameworks: Synthesis and Applications ; Enhanced Oil Recovery Techniques ; Machine Learning in Materials Science
Authors: Stefania Sandoval | Dejan Kepić | Ángel Pérez del Pino | E. M. Gyorgy | Andrés Gómez | Martin Pfannmoeller | Gustaaf Van Tendeloo | Belén Ballesteros | Gerard Tobías
Source: ACS Nano (article, 2018-07-05)
Field: Materials Science — Materials Chemistry

Selective Laser-Assisted Synthesis of Tubular van der Waals Heterostructures of Single-Layered PbI<sub>2</sub> within Carbon Nanotubes Exhibiting Carrier Photogeneration The electronic and optical properties of two-dimensional layered materials allow the miniaturization of nanoelectronic and optoelectronic devices in a competitive manner. Even larger opportunities arise when two or more layers of different materials are combined. Here, we report on an ultrafast energy efficient strategy, using laser irradiation, which allows bulk synthesis of crystalline single-layered lead iodide in the cavities of carbon nanotubes by forming cylindrical van der Waals heterostructures. In contrast to the filling of van der Waals solids into carbon nanotubes by conventional thermal annealing, which favors the formation of inorganic nanowires, the present strategy is highly selective toward the growth of monolayers forming lead iodide nanotubes. The irradiated bulk material bearing the nanotubes reveals a decrease of the resistivity as well as a significant increase in the current flow upon illumination. Both effects are attributed to the presence of single-walled lead iodide nanotubes in the cavities of carbon nanotubes, which dominate the properties of the whole matrix. The present study brings in a simple, ultrafast and energy efficient strategy for the tailored synthesis of rolled-up single-layers of lead iodide (i.e., single-walled PbI<sub>2</sub> nanotubes), which we believe could be expanded to other two-dimensional (2D) van der Waals solids. In fact, initial tests with ZnI<sub>2</sub> already reveal the formation of single-walled ZnI<sub>2</sub> nanotubes, thus proving the versatility of the approach. Carbon nanotube ; van der Waals force ; Materials science ; Nanotechnology ; Heterojunction ; Carbon nanobud ; Mechanical properties of carbon nanotubes ; Nanowire ; Nanotube ; Optical properties of carbon nanotubes ; Optoelectronics ; Chemistry ; Molecule ; Organic chemistry 2D Materials and Applications ; MXene and MAX Phase Materials ; Graphene research and applications
Authors: Jonathan Cailloux | Tobias Abt | Violeta García-Masabet | Orlando Onofre Santana Pérez | Miguel Sánchez‐Soto | F. Carrasco | M. Ll. Maspoch
Source: eXPRESS Polymer Letters (article, 2018-01-01)
Field: Materials Science — Biomaterials

Effect of the viscosity ratio on the PLA/PA10.10 bioblends morphology and mechanical properties PLA bio-blends with a predominantly biosourced PA10.10 in the composition range 10-50 wt% were prepared by melt blending in order to overcome the advanced brittleness of PLA. Due to the inherent immiscibility of the blends, 30 wt% of PA was needed to achieve a brittle-to-ductile transition and a co-continuous morphology was predicted at 58 wt% of PA. The initial enhancement of the PLA rheological behaviour through the environmentally friendly reactive extrusion process yielded a finer and more homogeneous microstructure and hence enhanced the mechanical properties of the bioblends at much lower PA contents. The brittle-to-ductile transition could be achieved with only 10 wt% and co-continuity was observed already at 44 wt% of PA. Results indicate the significant potential of modifying PLA flow behaviour as a promising green manufacturing method toward expanding PLA-based bio-blends applications. Materials science ; Rheology ; Brittleness ; Extrusion ; Morphology (biology) ; Composite material ; Microstructure ; Reactive extrusion ; Viscosity ; Environmentally friendly ; Homogeneous ; Chemical engineering ; Thermodynamics biodegradable polymer synthesis and properties ; Additive Manufacturing and 3D Printing Technologies ; Bone Tissue Engineering Materials