jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Heda Guan | Donglei Zou | Haiyang Yu | Meijun Liu | Zhi Liu | Wentian Sun | Feifan Xu | Yangxue Li
Source: Frontiers in Materials (article, 2019-02-19)
Field: Materials Science — Materials Chemistry

Adsorption Behavior of Iodine by Novel Covalent Organic Polymers Constructed Through Heterostructural Mixed Linkers The efficient capture and storage radioactive iodine (129I or 131I) formed during the extensive use of nuclear energy is of paramount importance. In this work, we presented a novel covalent organic polymer (JLUE-COP-3) constructed through heterostructural mixed linkers with perforated porousness, plenty of π-conjugated phenyl rings and functional –CO–NH– and –SO3H groups to iodine adsorption process. After fully characterizing the morphology and structure, the adsorption behavior of iodine by the resultant polymers were explored in detail. The external adsorption behavior was determined to obey the pseudo-second order kinetic model according to the kinetic analysis. The maximum liquid adsorption capacity was obtained to reach 153.85 mg/g at 298 K, which was evaluated by the Langmuir isotherm model. In addition, the negative attributes of ΔGo as well as the positive attributes of ΔHo and ΔSo at three temperatures, indicated the nature of the iodine adsorption over JLUE-COP-3 was spontaneous and endothermic. Adsorption ; Endothermic process ; Polymer ; Covalent bond ; Langmuir adsorption model ; Chemical engineering ; Conjugated system ; Materials science ; Chemistry ; Polymer chemistry ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Luminescence and Fluorescent Materials
Authors: Orestis Vryonis | Thomas Andritsch | A. S. Vaughan | P. L. Lewin
Source: Journal of Materials Science (article, 2019-02-27)
Field: Materials Science — Materials Chemistry

An alternative synthesis route to graphene oxide: influence of surface chemistry on charge transport in epoxy-based composites A synthetic route for the production of graphene oxide is described, in which the commonly used potassium permanganate (KMnO4) is replaced by chromium trioxide (CrO3) as the oxidizing agent. Raman spectroscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy demonstrate that the product is characterized by a reduced level of oxidation and a reduced defect content, compared to conventional graphene oxide (GO). We therefore term the product moderately oxidized graphene oxide (mGO). In comparison with GO, it is shown that when introduced into an epoxy matrix, mGO offers significant potential benefits. These include: excellent compatibility with the epoxy matrix leading to a low percolation threshold for electrical conductivity (~ 0.5 vol%); an associated increase in electrical conductivity of about eight orders of magnitude; no adverse influence on the epoxy curing reactions; potentially simplified material processing strategies. Epoxy ; Graphene ; Materials science ; Oxide ; Thermogravimetric analysis ; Oxidizing agent ; X-ray photoelectron spectroscopy ; Raman spectroscopy ; Composite material ; Potassium permanganate ; Percolation threshold ; Chemical engineering ; Curing (chemistry) ; Inorganic chemistry ; Electrical resistivity and conductivity ; Nanotechnology ; Organic chemistry ; Chemistry Graphene research and applications ; Polymer Nanocomposite Synthesis and Irradiation ; High voltage insulation and dielectric phenomena
Authors: Ru Zhou | Biqing Huang | Yanming Ding | Wenjuan Li | Jingjing Mu
Source: Polymers (article, 2019-12-12)
Field: Materials Science — Materials Chemistry

Thermal Decomposition Mechanism and Kinetics Study of Plastic Waste Chlorinated Polyvinyl Chloride Chlorinated polyvinyl chloride (CPVC), as a new type of engineering plastic waste, has been used widely due to its good heat resistance, mechanical properties and corrosion resistance, while it has become an important part of solid waste. The pyrolysis behaviors of CPVC waste were analyzed based on thermogravimetric experiments to explore its reaction mechanism. Compared with polyvinyl chloride (PVC) pyrolysis, CPVC pyrolysis mechanism was divided into two stages and speculated to be dominated by the dehydrochlorination and cyclization/aromatization processes. A common model-free method, Flynn-Wall-Ozawa method, was applied to estimate the activation energy values at different conversion rates. Meanwhile, a typical model-fitting method, Coats-Redfern method, was used to predict the possible reaction model by the comparison of activation energy obtained from model-free method, thereby the first order reaction-order model and fourth order reaction-order model were established corresponding to these two stages. Eventually, based on the initial kinetic parameter values computed by model-free method and reaction model established by model-fitting method, kinetic parameters were optimized by Shuffled Complex Evolution algorithm and further applied to predict the CPVC pyrolysis behaviors during the whole temperature range. Chlorinated polyvinyl chloride ; Polyvinyl chloride ; Pyrolysis ; Activation energy ; Materials science ; Thermogravimetric analysis ; Order of reaction ; Kinetics ; Reaction mechanism ; Thermal decomposition ; Decomposition ; Exothermic reaction ; Chemical engineering ; Reaction rate constant ; Thermodynamics ; Composite material ; Chemistry ; Organic chemistry ; Catalysis Thermal and Kinetic Analysis ; Polymer Science and PVC ; Thermochemical Biomass Conversion Processes
Authors: Kristina Bruun | Carsten Hille
Source: Scientific Reports (article, 2019-07-19)
Field: Materials Science — Materials Chemistry

Study on intracellular delivery of liposome encapsulated quantum dots using advanced fluorescence microscopy Quantum dots increasingly gain popularity for in vivo applications. However, their delivery and accumulation into cells can be challenging and there is still lack of detailed information. Thereby, the application of advanced fluorescence techniques can expand the portfolio of useful parameters for a more comprehensive evaluation. Here, we encapsulated hydrophilic quantum dots into liposomes for studying cellular uptake of these so-called lipodots into living cells. First, we investigated photophysical properties of free quantum dots and lipodots observing changes in the fluorescence decay time and translational diffusion behaviour. In comparison to empty liposomes, lipodots exhibited an altered zeta potential, whereas their hydrodynamic size did not change. Fluorescence lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS), both combined with two-photon excitation (2P), were used to investigate the interaction behaviour of lipodots with an insect epithelial tissue. In contrast to the application of free quantum dots, their successful delivery into the cytosol of salivary gland duct cells could be observed when applying lipodots. Lipodots with different lipid compositions and surface charges did not result in considerable differences in the intracellular labelling pattern, luminescence decay time and diffusion behaviour. However, quantum dot degradation after intracellular accumulation could be assumed from reduced luminescence decay times and blue-shifted luminescence signals. In addition to single diffusing quantum dots, possible intracellular clustering of quantum dots could be assumed from increased diffusion times. Thus, by using a simple and manageable liposome carrier system, 2P-FLIM and 2P-FCS recording protocols could be tested, which are promising for investigating the fate of quantum dots during cellular interaction. Quantum dot ; Liposome ; Fluorescence correlation spectroscopy ; Biophysics ; Luminescence ; Intracellular ; Fluorescence ; Fluorescence-lifetime imaging microscopy ; Microscopy ; Fluorescence microscope ; Materials science ; Nanotechnology ; Chemistry ; Optoelectronics ; Physics ; Biology ; Optics ; Biochemistry Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Carbon and Quantum Dots Applications
Authors: Abhinav Jain | Patrick A. Burr | Dallas R. Trinkle
Source: Physical Review Materials (article, 2019-03-18)
Field: Materials Science — Materials Chemistry

First-principles calculations of solute transport in zirconium: Vacancy-mediated diffusion with metastable states and interstitial diffusion Zirconium alloys are the most widely used nuclear fuel cladding materials for light water power reactors where irradiation damage causes solute redistribution, leading to degradation of alloy properties such as corrosion resistance. Designing radiation-tolerant zirconium alloys requires a thorough understanding of the atomic-scale transport behavior of the alloying elements in Zr. We perform density function theory calculations to investigate the diffusion of Sn, Cr, Fe, Be, Al, and Ni in the hexagonal close-packed (HCP) Zr matrix. We develop a methodology to accurately model the metastable vacancy states along the basal migration path, known to occur in group IV metals. We compute the vacancy-mediated solute diffusion coefficients and drag ratios using the kinetic Monte Carlo method and an analytic Green's function method---the agreement between the two validates our methodology. The computed diffusion coefficients of Sn and Al show good agreement with the experimental data and we expect these solutes to diffuse via the vacancy-mediated mechanism. We use a Green's function approach, parameterized with data from density functional theory calculations, to compute the interstitial diffusion coefficients of Cr, Fe, Be, and Ni in the HCP Zr lattice. The computed diffusion coefficients of Cr, Ni, and Be agree with the experimental measurements within one order of magnitude, while those of Fe are within two orders of magnitude of the experimental measurements. The drag ratios for Cr, Fe, Be, and Ni are positive up to 1235 K, which suggests that nonequilibrium vacancy fluxes could drag these solutes toward sinks such as dislocation loops and grain boundaries. We also compute the transport coefficients without including the metastable states, and using the eight- and thirteen-frequency model. Our results show significant differences in drag ratio for the eight- and thirteen-frequency model predictions compared with the Green's function methodology, but smaller errors in the solute diffusivity. Combining interstitial and vacancy-mediated diffusivities, we predict the unusual result that increased vacancy concentration slows down solute diffusivity, while a sufficiently high vacancy concentration can change the dominant mechanism to an accelerated vacancy-mediated diffusion. Materials science ; Vacancy defect ; Zirconium ; Solvent drag ; Diffusion ; Thermodynamics ; Metastability ; Alloy ; Lattice diffusion coefficient ; Density functional theory ; Kinetic Monte Carlo ; Chemical physics ; Condensed matter physics ; Metallurgy ; Microstructure ; Effective diffusion coefficient ; Monte Carlo method ; Computational chemistry ; Grain boundary ; Chemistry ; Physics Nuclear Materials and Properties ; Fusion materials and technologies ; Nuclear reactor physics and engineering
Authors: Dinesh Kumar Yadav | Parshant Kaushik | Pankaj | Virendra Singh Rana | Deeba Kamil | Dilip Khatri | Najam Akhtar Shakil
Source: Frontiers in Chemistry (article, 2019-11-26)
Field: Chemistry — Organic Chemistry

Microwave Assisted Synthesis, Characterization and Biological Activities of Ferrocenyl Chalcones and Their QSAR Analysis A new microwave method (MM) has been developed for the synthesis of a series of 16 substituted ferrocenyl chalcones using acetylferrocene (<b>1</b>) with different aldehydes (<b>2a-2p</b>) and comparing it with conventional method (CM). The synthesized compounds were characterized by various spectroscopic techniques <i>viz</i> IR, HR-MS, <sup>1</sup>H NMR, and <sup>13</sup>C NMR. The time required for completion of reaction in MM varied from 1 to 5 min as compared to CM which required 10-40 h. All the synthesized compounds were screened for antifungal activity against <i>Sclerotium rolfsii</i> and <i>Alternaria solani</i>. <i>In vitro</i> fungicidal activity revealed that compound <b>3o</b> (ED<sub>50</sub> = 23.24 mg L<sup>-1</sup>) was found to be most active against <i>S. rolfsii</i>. But in case of <i>A. solani</i>, compound <b>3c</b> (ED<sub>50</sub> = 29.9 mg L<sup>-1</sup>) showed highest activity. The nematicidal activity revealed that the compound <b>3b</b> was more potent with LC<sub>50</sub> values of 10.67, 7.30, and 4.55 ppm at 24, 48, and 72 h, respectively. 2D-Quantitative Structural Activity Relationship (2D-QSAR) analysis of these ferrocenyl chalcones was carried out by developing three different models namely Partial Least Squares (PLS, Model 1), Multiple Linear Regression (MLR, Model 2) and Principal Component Regression (PCR, Model 3). Statistical significance and predictive ability of these models were assessed by internal and external validation and also verified by leave one-out cross-validation. QSAR study revealed that MLR for <i>S. rolfsii</i> (<i>r</i> <sup>2</sup> = 0.999, <i>q</i> <sup>2</sup> = 0.996), PLS for <i>A. solani</i> (<i>r</i> <sup>2</sup> = 0.934, <i>q</i> <sup>2</sup> = 0.749) and PCR for <i>M. incognita</i> (<i>r</i> <sup>2</sup> = 0.878, <i>q</i> <sup>2</sup> = 0.772) were the best model. The physico-chemical parameters were calculated using VLife MDS 4.6 software. QSAR study could be employed for structure optimization to achieve better activity. Quantitative structure–activity relationship ; Chemistry ; Chalcone ; Proton NMR ; Sclerotium ; Meloidogyne incognita ; Stereochemistry ; Partial least squares regression ; Nuclear chemistry ; Organic chemistry ; Mathematics ; Nematode ; Botany Ferrocene Chemistry and Applications ; Synthesis and biological activity ; Multicomponent Synthesis of Heterocycles
Authors: Tommaso Morresi | Andrea Pedrielli | S. a Beccara | Ruggero Gabbrielli | Nicola M. Pugno | Simone Taioli
Source: Carbon (article, 2019-12-16)
Field: Materials Science — Materials Chemistry

Structural, electronic and mechanical properties of all-sp2 carbon allotropes with density lower than graphene Graphene ; Materials science ; Planar ; Rigidity (electromagnetism) ; Carbon fibers ; Fermi level ; Density of states ; Graphyne ; Phonon ; Electronic band structure ; Electronic structure ; Condensed matter physics ; Work (physics) ; Nanotechnology ; Composite material ; Physics ; Composite number ; Thermodynamics ; Computer science Graphene research and applications ; 2D Materials and Applications ; Boron and Carbon Nanomaterials Research
Authors: Baoqin Lin | Jianxin Guo | Lintao Lv | Zhe Liu | Xiang Ji | Jing Wu
Source: IEEE Access (article, 2019-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

An Ultra-Wideband Reflective Phase Gradient Metasurface Using Pancharatnam-Berry Phase Designing a transmissive and reflective phase gradient metasurface (PGM) using Pancharatnam–Berry (PB) geometrical phase must be based on an appropriate metasurface, which can realize circular-polarization (CP)-conversion transmission and CP-maintaining reflection, respectively. When an appropriate metasurface is proposed, a PGM can be easily constructed by gradually rotating the anisotropic or chiral resonators in different unit cells. In this paper, to design an ultra-wideband reflective PGM, first, an ultra-wideband CP-maintaining metasurface is proposed, and the numerical simulation results show that the proposed metasurface can realize CP-maintaining reflection at CP incidence between 8.43 and 26.93 GHz; in addition, a PB phase will be generated in its co-polarized reflection coefficient by rotating the anisotropic resonators in its unit cells. Thus, based on the metasurface, an ultra-wideband PGM is constructed successfully, the simulated and experimental results show that the PGM can realize ultra-wideband anomalous reflection at arbitrarily polarized incidence, and almost all the reflected waves at right-handed and left-handed CP (RHCP and LHCP) incidences will both be deflected to an anomalous direction; in addition, the reflected waves at linear and elliptical polarized (LP and EP) incidences will be separated into two beams for the LP and EP waves that can both be decomposed into a pair of RHCP and LHCP waves. Furthermore, finally, a detailed theoretical analysis is presented for the CP-maintaining reflection of the proposed metasurface. Wideband ; Physics ; Resonator ; Optics ; Polarization (electrochemistry) ; Reflection (computer programming) ; Reflection coefficient ; Anisotropy ; Phase (matter) ; Linear polarization ; Geometric phase ; Computer science Metamaterials and Metasurfaces Applications ; Antenna Design and Analysis ; Advanced Antenna and Metasurface Technologies
Authors: Davıd L. Andrews
Source: Methods and Applications in Fluorescence (article, 2019-03-19)
Field: Chemistry — Spectroscopy

Chirality in fluorescence and energy transfer Optical polarization features associated with the fundamental processes of molecular fluorescence and resonance energy transfer are in general studied with reference to plane polarizations. When any of the species involved is chiral, the associated emission processes may exhibit an element of circular polarization-a degree of optical helicity. Although usually a minor effect, some systems can exhibit a sizeable component of circularly polarized luminescence, whose helicity correlates with the enantiomeric form. In studies of multi-component systems, in which initial excitation of a donor species-followed by energy transfer-leads to emission from an acceptor molecule, the handedness of both donor and acceptor may influence output circularity. In systems with an achiral acceptor, a degree of fluorescence circularity may be influenced by the handedness of a chiral donor, but this should not be construed in terms of 'conveying' chirality. Chiral molecules may also play a passive role by inducing helicity in the fluorescence from achiral neighbours, and further tiers of complexity arise if the initial excitation is itself of circular polarization. In all such processes, symmetry principles play a major role in determining a sensitivity to molecular handedness, and their detailed consideration enables a range of new experimental procedures to be identified. Casting the fundamental theory in terms of formal photon-molecule couplings enables the quantum mechanisms involved in all such phenomena to be clearly resolved. The results provide fresh physical insights, and establish connections across a range of indirectly related chiroptical phenomena including induced circular dichroism. Energy transfer ; Chirality (physics) ; Fluorescence ; Förster resonance energy transfer ; Chemistry ; Physics ; Chemical physics ; Optics ; Nuclear physics Molecular spectroscopy and chirality ; Photoreceptor and optogenetics research ; Spectroscopy and Quantum Chemical Studies
Authors: Alena Gribko | Julian Künzel | Desirée Wünsch | Qiang Lü | Sophie Madeleine Nagel | Shirley K. Knauer | Roland H. Stauber | Guo‐Bin Ding
Source: International Journal of Nanomedicine (review, 2019-06-01)
Field: Materials Science — Biomaterials

&lt;p&gt;Is small smarter? Nanomaterial-based detection and elimination of circulating tumor cells: current knowledge and perspectives&lt;/p&gt; Circulating tumor cells (CTCs) are disseminated cancer cells. The occurrence and circulation of CTCs seem key for metastasis, still the major cause of cancer-associated deaths. As such, CTCs are investigated as predictive biomarkers. However, due to their rarity and heterogeneous biology, CTCs' practical use has not made it into the clinical routine. Clearly, methods for the effective isolation and reliable detection of CTCs are urgently needed. With the development of nanotechnology, various nanosystems for CTC isolation and enrichment and CTC-targeted cancer therapy have been designed. Here, we summarize the relationship between CTCs and tumor metastasis, and describe CTCs' unique properties hampering their effective enrichment. We comment on nanotechnology-based systems for CTC isolation and recent achievements in microfluidics and lab-on-a-chip technologies. We discuss recent advances in CTC-targeted cancer therapy exploiting the unique properties of nanomaterials. We conclude by introducing developments in CTC-directed nanosystems and other advanced technologies currently in (pre)clinical research. Nanomaterials ; Nanotechnology ; Cancer research ; Materials science ; Medicine Nanoparticle-Based Drug Delivery ; Cancer Cells and Metastasis ; Nanoplatforms for cancer theranostics
Authors: Eduardo Carasek | Gabrieli Bernardi | Sângela Nascimento do Carmo | Camila M.S. Vieira
Source: Separations (article, 2019-07-16)
Field: Chemistry — Analytical Chemistry

Alternative Green Extraction Phases Applied to Microextraction Techniques for Organic Compound Determination The use of green extraction phases has gained much attention in different fields of study, including in sample preparation for the determination of organic compounds by chromatography techniques. Green extraction phases are considered as an alternative to conventional phases due to several advantages such as non-toxicity, biodegradability, low cost and ease of preparation. In addition, the use of greener extraction phases reinforces the environmentally-friendly features of microextraction techniques. Thus, this work presents a review about new materials that have been used in extraction phases applied to liquid and sorbent-based microextractions of organic compounds in different matrices. Extraction (chemistry) ; Sorbent ; Solid-phase microextraction ; Sample preparation ; Environmentally friendly ; Chromatography ; Chemistry ; Materials science ; Gas chromatography–mass spectrometry ; Organic chemistry ; Mass spectrometry ; Adsorption Analytical chemistry methods development ; Analytical Chemistry and Chromatography ; Electrochemical Analysis and Applications
Authors: Feng Huo | Yuhang Liu | Mingguang Zhu | En Gao | Bin Zhao | Xiupei Yang
Source: ACS Applied Materials & Interfaces (article, 2019-07-08)
Field: Materials Science — Materials Chemistry

Ultrabright Full Color Carbon Dots by Fine-Tuning Crystal Morphology Controllable Synthesis for Multicolor Bioimaging and Sensing In this paper, two kinds of novel carbon nanocrystals (CNCs) with different crystal morphologies (the branch-chain young sprout form (CM1) and conifer-pine form (CM2)) were obtained in a controllable way. The mechanism of crystal morphological development was explored well. When the two kinds of the CNCs were dissolved in different polar solvents, they voluntarily become "ultrafine crystals" at the moment. After that, the ultrabright full color carbon dots (UBFCCDs) have been preliminarily prepared by fine-controlling. With the evaporation of the solvents, the CNCs crystallized again, which could repeat back and forth many times. After the conditions of preparing for CDs were optimized carefully, the as-prepared CDs exhibit ultrabright effects of multiexcitation and multiemission (from blue to red) and can show unique up-conversion luminescence characteristics under a lower excitation wavelength of 660 nm instead of a near-infrared wavelength of 980 or 808 nm. Significantly, the QY% of the UBFCCDs can reach 78.0%, which is higher than that of the traditional hydrothermal methods of discarding precipitation and carrying out dialysis (QY% = 69.0%). The as-prepared CDs can be used for multicolor biomedical imaging in vivo and in vitro and metal ion sensing and also show their potential value for industrial applications. Materials science ; Carbon fibers ; Crystal (programming language) ; Nanotechnology ; Luminescence ; Hydrothermal circulation ; Evaporation ; Nanocrystal ; Precipitation ; Optoelectronics ; Chemical engineering Carbon and Quantum Dots Applications ; Nanocluster Synthesis and Applications ; Graphene and Nanomaterials Applications