jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Xiaoli Chen | Jingyi Pan | Jing‐jing Fu | Xin Zhu | Chen Zhang | Li Zhou | Yan Wang | Ziyu Lv | Ye Zhou | Su‐Ting Han
Source: Advanced Electronic Materials (article, 2018-09-20)
Field: Materials Science — Materials Chemistry

Polyoxometalates‐Modulated Reduced Graphene Oxide Flash Memory with Ambipolar Trapping as Bidirectional Artificial Synapse Abstract Employing flash memories that function as the analogue synapse cleft for implementation of neural systems is a popular approach. For practical application in synapse mimicking, ambipolar trapping of both holes and electrons enables the weight updated linearity, symmetric conductivity variation, and desired variation margin, which are consistent with biological synapse. Nevertheless, most of the flash memory exhibits unipolar charge trapping behavior. Here, the first polyoxometalates (POMs)‐modulated reduced graphene oxide (RGO)‐based flash memory with ambipolar charge trapping characteristics is reported. Keggin type [PW 12 O 40 ] 3− (PW) is selected to function as both catalyst for in situ photoreduction of the graphene oxide (GO) into RGO under UV illumination and electron trapping sites. The electrons accepting property of PW induces energy level realignment between the PW/RGO interface and the subsequent ambipolar charge trapping. Furthermore, the selected features of biological synaptic behavior, including short‐term plasticity and long‐term plasticity as well as paired pulse facilitation and depression, are mimicked. It is worth noting that almost symmetrical potentiation and depression synaptic behavior is obtained. This work provides new opportunities to realize reconfigurable characteristics of electronic devices via engineering of POMs, which is significantly meaningful to emerging artificial intelligence. Graphene ; Ambipolar diffusion ; Materials science ; Oxide ; Flash memory ; Trapping ; Optoelectronics ; Nanotechnology ; Electron ; Synapse ; Computer science ; Physics ; Neuroscience ; Embedded system Polyoxometalates: Synthesis and Applications ; Advanced Memory and Neural Computing ; Advanced Nanomaterials in Catalysis
Authors: Sidsel Ammitzbøll Bogh | Miguel R. Carro‐Temboury | Cecilia Cerretani | Steven M. Swasey | Stacy M. Copp | E. G. Gwinn | Tom Vosch
Source: Methods and Applications in Fluorescence (article, 2018-02-09)
Field: Materials Science — Materials Chemistry

Unusually large Stokes shift for a near-infrared emitting DNA-stabilized silver nanocluster In this paper we present a new near-IR emitting silver nanocluster (NIR-DNA-AgNC) with an unusually large Stokes shift between absorption and emission maximum (211 nm or 5600 cm<sup>-1</sup>). We studied the effect of viscosity and temperature on the steady state and time-resolved emission. The time-resolved results on NIR-DNA-AgNC show that the relaxation dynamics slow down significantly with increasing viscosity of the solvent. In high viscosity solution, the spectral relaxation stretches well into the nanosecond scale. As a result of this slow spectral relaxation in high viscosity solutions, a multi-exponential fluorescence decay time behavior is observed, in contrast to the more mono-exponential decay in low viscosity solution. Viscosity ; Stokes shift ; Relaxation (psychology) ; Nanosecond ; Exponential decay ; Absorption (acoustics) ; Materials science ; Emission spectrum ; Exponential function ; Analytical Chemistry (journal) ; Chemistry ; Luminescence ; Spectral line ; Optics ; Optoelectronics ; Physics ; Laser Nanocluster Synthesis and Applications ; Gold and Silver Nanoparticles Synthesis and Applications ; Advanced Nanomaterials in Catalysis
Authors: Batirtze Prats‐Mateu | Martin Felhofer | Anna de Juan | Notburga Gierlinger
Source: Plant Methods (article, 2018-07-04)
Field: Chemistry — Analytical Chemistry

Multivariate unmixing approaches on Raman images of plant cell walls: new insights or overinterpretation of results? VCA is recommended as a good preliminary approach, since it is fast, does not require setting many input parameters and the endmember spectra result in good approximations of the raw data. Yet the endmember spectra are more correlated and mixed than those retrieved by NMF and MCR-ALS methods. The latter two give the best model statistics (with lower lack of fit in the models), but care has to be taken about overestimating the rank as it can lead to artificial shapes due to peak splitting or inverted bands. Multivariate statistics ; Raman spectroscopy ; Multivariate analysis ; Artificial intelligence ; Computer science ; Mathematics ; Statistics ; Optics ; Physics Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Phytochemicals and Antioxidant Activities
Authors: Peng Chen | Xiaohu Liu | Garima Goyal | Nhung Thi Tran | James C. S. Ho | Yi Wang | Daniel Aili | Bo Liedberg
Source: Analytical Chemistry (article, 2018-03-15)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Nanoplasmonic Sensing from the Human Vision Perspective Localized surface plasmon resonance (LSPR) constitutes a versatile technique for biodetection, exploiting the sensitivity of plasmonic nanostructures to small changes in refractive index. The optical shift in the LSPR band caused by molecular interactions in the vicinity of the nanostructures are typically <5 nm and can readily be detected by a spectrophotometer. Widespread use of LSPR-based sensors require cost-effective devices and would benefit from sensing schemes that enables use of very simple spectrophotometers or even naked-eye detection. This paper describes a new strategy facilitating visualization of minute optical responses in nanoplasmonic bioassays by taking into account the physiology of human color vision. We demonstrate, using a set of nine different plasmonic nanoparticles, that the cyan to green transition zone at ∼500 nm is optimal for naked-eye detection of color changes. In this wavelength range, it is possible to detect a color change corresponding to a wavelength shift of ∼2-3 nm induced by refractive index changes in the medium or by molecular binding to the surface of the nanoparticles. This strategy also can be utilized to improve the performance of aggregation-based nanoplasmonic colorimetric assays, which enables semiquantitative naked-eye detection of matrix metalloproteinase 7 (MMP7) activity at concentrations that are at least 5 times lower than previously reported assays using spherical gold nanoparticles. We foresee significant potential of this strategy in medical diagnostic and environmental monitoring, especially in situations where basic laboratory infrastructure is sparse or even nonexistent. Finally, we demonstrate that the developed concept can be used in combination with cell phone technology and red-green-blue (RGB) analysis for sensitive and quantitative detection of MMP7. Chemistry ; Perspective (graphical) ; Nanotechnology ; Artificial intelligence Gold and Silver Nanoparticles Synthesis and Applications ; Biosensors and Analytical Detection ; Advanced biosensing and bioanalysis techniques
Authors: Liliang Huang | Pengcheng Chen | Mohan Liu | Xianbiao Fu | Pavlo Gordiichuk | Yanan Yu | Chris Wolverton | Yijin Kang | Chad A. Mirkin
Source: Proceedings of the National Academy of Sciences (article, 2018-03-23)
Field: Materials Science — Materials Chemistry

Catalyst design by scanning probe block copolymer lithography Scanning probe block copolymer lithography (SPBCL), in combination with density-functional theory (DFT), has been used to design and synthesize hydrogen evolution catalysts. DFT was used to calculate the hydrogen adsorption energy on a series of single-element, bimetallic, and trimetallic (Au, Pt, Ni, and Cu) substrates to provide leads that could be synthesized in the form of alloy or phase-separated particles via SPBCL. PtAuCu (18 nm, ∼1:1:1 stoichiometry) has been identified as a homogeneous alloy phase that behaves as an effective hydrogen evolution catalyst in acidic aqueous media, even when it is made in bulk form via solution phase methods. Significantly, the bulk-prepared PtAuCu/C nanocatalyst discovered via this process exhibits an activity seven times higher than that of the state-of-the-art commercial Pt/C catalyst (based upon Pt content). The advantage of using SPBCL in the discovery process is that one can uniformly make particles, each consisting of a uniform phase combination (e.g., all alloy or all phase-segregated species) at a fixed elemental ratio, an important consideration when working with polyelemental species where multiple phases may exist. Catalysis ; Lithography ; Copolymer ; Nanotechnology ; Computer science ; Field (mathematics) ; Work (physics) ; Materials science ; Block (permutation group theory) ; Process engineering ; Stoichiometry ; Biochemical engineering ; Chemistry ; Polymer ; Mechanical engineering ; Engineering ; Mathematics ; Organic chemistry ; Optoelectronics Machine Learning in Materials Science ; Block Copolymer Self-Assembly ; Ferroelectric and Negative Capacitance Devices
Authors: Denis Machon | Vittoria Pischedda | Sylvie Le Floch | A. San Miguel
Source: Journal of Applied Physics (article, 2018-10-28)
Field: Chemistry — Organic Chemistry

Perspective: High pressure transformations in nanomaterials and opportunities in material design Pressure and temperature phase transitions of nanomaterials often differ significantly from those of their bulk parents, offering novel approaches for the engineering of original materials. The importance or even the dominance of surface atoms in the nanoworld enhances the effects of environment, geometry, and intercalation. In the present article, we explore the current knowledge of these effects, as evidenced in the high pressure phase diagrams of nanomaterials such as nanocrystals, carbon nanotubes, fullerites, graphene, and other 2D systems, as well as nanoporous structures like clathrates or zeolites. Recent advances and future challenges in the use of extreme thermodynamic conditions to develop new functional nanomaterials, composites, or devices will be reviewed, along with the specificities of the experimental environment required for these investigations. Nanomaterials ; Nanotechnology ; Materials science ; Nanoporous ; Graphene ; Carbon nanotube ; High pressure ; Engineering physics ; Engineering Fullerene Chemistry and Applications ; Carbon Nanotubes in Composites ; Graphene research and applications
Authors: Aude-Héloïse Bonardi | Frédéric Dumur | Guillaume Noirbent | Jacques Lalevée | Didier Gigmès
Source: Beilstein Journal of Organic Chemistry (review, 2018-12-12)
Field: Chemistry — Organic Chemistry

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region Recent progresses achieved in terms of synthetic procedures allow now the access to polymers of well-defined composition, molecular weight and architecture. Thanks to these recent progresses in polymer engineering, the scope of applications of polymers is far wider than that of any other class of material, ranging from adhesives, coatings, packaging materials, inks, paints, optics, 3D printing, microelectronics or textiles. From a synthetic viewpoint, photoredox catalysis, originally developed for organic chemistry, has recently been applied to the polymer synthesis, constituting a major breakthrough in polymer chemistry. Thanks to the development of photoredox catalysts of polymerization, a drastic reduction of the amount of photoinitiators could be achieved, addressing the toxicity and the extractability issues; high performance initiating abilities are still obtained due to the catalytic approach which regenerates the catalyst. As it is a fast-growing field, this review will be mainly focused on an overview of the recent advances concerning the development of organic and organometallic photoredox catalysts for the photoreticulation of multifunctional monomers for a rapid and efficient access to 3D polymer networks. Photoredox catalysis ; Polymer ; Nanotechnology ; Chemistry ; Microelectronics ; Catalysis ; Organic synthesis ; Polymerization ; Polymer science ; Organic chemistry ; Materials science ; Photocatalysis Photopolymerization techniques and applications ; Radical Photochemical Reactions ; Advanced Polymer Synthesis and Characterization
Authors: Stavros Alexandros Theofanidis | Vladimir Galvita | Christos Konstantopoulos | Hilde Poelman | Guy Marin
Source: Materials (review, 2018-05-17)
Field: Materials Science — Materials Chemistry

Fe-Based Nano-Materials in Catalysis The role of iron in view of its further utilization in chemical processes is presented, based on current knowledge of its properties. The addition of iron to a catalyst provides redox functionality, enhancing its resistance to carbon deposition. FeO<sub>x</sub> species can be formed in the presence of an oxidizing agent, such as CO₂, H₂O or O₂, during reaction, which can further react via a redox mechanism with the carbon deposits. This can be exploited in the synthesis of active and stable catalysts for several processes, such as syngas and chemicals production, catalytic oxidation in exhaust converters, etc. Iron is considered an important promoter or co-catalyst, due to its high availability and low toxicity that can enhance the overall catalytic performance. However, its operation is more subtle and diverse than first sight reveals. Hence, iron and its oxides start to become a hot topic for more scientists and their findings are most promising. The scope of this article is to provide a review on iron/iron-oxide containing catalytic systems, including experimental and theoretical evidence, highlighting their properties mainly in view of syngas production, chemical looping, methane decomposition for carbon nanotubes production and propane dehydrogenation, over the last decade. The main focus goes to Fe-containing nano-alloys and specifically to the Fe⁻Ni nano-alloy, which is a very versatile material. Catalysis ; Dehydrogenation ; Oxidizing agent ; Syngas ; Redox ; Materials science ; Carbon fibers ; Oxide ; Carbon nanotube ; Methane ; Chemical engineering ; Nanotechnology ; Chemistry ; Metallurgy ; Organic chemistry ; Composite material Catalytic Processes in Materials Science ; Catalysts for Methane Reforming ; Electrocatalysts for Energy Conversion
Authors: Martina Kirilova | Virginia Toy | Jeremy S. Rooney | Carolina Giorgetti | Keith C. Gordon | Cristiano Collettini | Toru Takeshita
Source: Solid Earth (article, 2018-02-27)
Field: Materials Science — Materials Chemistry

Structural disorder of graphite and implications for graphite thermometry Abstract. Graphitization, or the progressive maturation of carbonaceous material, is considered an irreversible process. Thus, the degree of graphite crystallinity, or its structural order, has been calibrated as an indicator of the peak metamorphic temperatures experienced by the host rocks. However, discrepancies between temperatures indicated by graphite crystallinity versus other thermometers have been documented in deformed rocks. To examine the possibility of mechanical modifications of graphite structure and the potential impacts on graphite thermometry, we performed laboratory deformation experiments. We sheared highly crystalline graphite powder at normal stresses of 5 and 25 megapascal (MPa) and aseismic velocities of 1, 10 and 100 µm s−1. The degree of structural order both in the starting and resulting materials was analyzed by Raman microspectroscopy. Our results demonstrate structural disorder of graphite, manifested as changes in the Raman spectra. Microstructural observations show that brittle processes caused the documented mechanical modifications of the aggregate graphite crystallinity. We conclude that the calibrated graphite thermometer is ambiguous in active tectonic settings. Graphite ; Crystallinity ; Raman spectroscopy ; Materials science ; Composite material ; Brittleness ; Deformation (meteorology) ; Aggregate (composite) ; Mineralogy ; Metamorphic rock ; Geology ; Geochemistry ; Optics Graphite, nuclear technology, radiation studies ; High-pressure geophysics and materials ; Nuclear materials and radiation effects
Authors: Xin Qian | Ronggui Yang
Source: Physical review. B./Physical review. B (article, 2018-12-27)
Field: Materials Science — Materials Chemistry

Temperature effect on the phonon dispersion stability of zirconium by machine learning driven atomistic simulations It is well known that conventional harmonic lattice dynamics cannot be applied to dynamically unstable crystals at 0 K, such as the high-temperature body centered cubic (bcc) phase of crystalline Zr. Predicting phonon spectra at finite temperature requires the calculation of force constants to the third, fourth, and even higher orders; however, it remains challenging to determine at which order the Taylor expansion of the potential-energy surface for different materials should be cut off. Molecular dynamics, on the other hand, intrinsically includes arbitrary orders of phonon anharmonicity; however, its accuracy is severely limited by the empirical potential field used. Recently, machine learning algorithms have emerged as promising tools to build accurate potentials for molecular dynamics simulation. In this paper, we approach the problem of predicting phonon dispersion at finite temperature by performing molecular dynamics simulations with machine learning driven potential fields. We developed Gaussian approximation potential models for both the hexagonal close packed (hcp) phase and the bcc phase of zirconium crystals. The developed potential field is first validated with static properties including energy-volume relationship, elastic constants, and phonon dispersions at 0 K. Molecular dynamics simulations are then performed to stochastically sample the potential-energy surface and to calculate the phonon dispersion at elevated temperatures. The phonon renormalization in bcc Zr is successfully captured by the molecular dynamics simulation at 1188 K. The instability of the bcc structure is found to originate from the double-well shape of the potential-energy surface where the local maximum is located in an unstable equilibrium position. The stabilization of the bcc phase at high temperature is due to the dynamical average of the low-symmetry minima of the double well due to atomic vibrations. Phonon ; Anharmonicity ; Molecular dynamics ; Potential energy ; Condensed matter physics ; Surface phonon ; Maxima and minima ; Materials science ; Morse potential ; Lattice (music) ; Force field (fiction) ; Physics ; Atomic physics ; Quantum mechanics Nuclear Materials and Properties ; Machine Learning in Materials Science ; Thermal properties of materials
Authors: Souad Rakass | Hicham Oudghiri Hassani | Mostafa Abboudi | Fethi Kooli | Ahmed Mohmoud | Ateyatallah Aljuhani | Fahd Al Wadaani
Source: Molecules (article, 2018-09-08)
Field: Chemistry — Inorganic Chemistry

Molybdenum Trioxide: Efficient Nanosorbent for Removal of Methylene Blue Dye from Aqueous Solutions Nano Molybdenum trioxide (α-MoO₃) was synthesized in an easy and efficient approach. The removal of methylene blue (MB) in aqueous solutions was studied using this material. The effects of various experimental parameters, for example contact time, pH, temperature and initial MB concentration on removal capacity were explored. The removal of MB was significantly affected by pH and temperature and higher values resulted in increase of removal capacity of MB. The removal efficiency of Methylene blue was 100% at pH = 11 for initial dye concentrations lower than 150 ppm, with a maximum removal capacity of 152 mg/g of MB as gathered from Langmuir model. By comparing the kinetic models (pseudo first-order, pseudo second-order and intraparticle diffusion model) at various conditions, it has been found that the pseudo second-order kinetic model correlates with the experimental data well. The thermodynamic study indicated that the removal was endothermic, spontaneous and favorable. The thermal regeneration studies indicated that the removal efficiency (99%) was maintained after four cycles of use. Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM) confirmed the presence of the MB dye on the α-MoO₃ nanoparticles after adsorption and regeneration. The α-MoO₃ nanosorbent showed excellent removal efficiency before and after regeneration, suggesting that it can be used as a promising adsorbent for removing Methylene blue dye from wastewater. Methylene blue ; Aqueous solution ; Molybdenum trioxide ; Chemistry ; Molybdenum blue ; Molybdenum ; Nuclear chemistry ; Methylene ; Photochemistry ; Inorganic chemistry ; Organic chemistry ; Photocatalysis Metal-Organic Frameworks: Synthesis and Applications ; Adsorption and biosorption for pollutant removal ; Nanomaterials for catalytic reactions
Authors: Katelyn Rose Bittleman | Shuping Dong | Maren Roman | Yong Woo Lee
Source: ACS Omega (article, 2018-10-24)
Field: Materials Science — Biomaterials

Folic Acid-Conjugated Cellulose Nanocrystals Show High Folate-Receptor Binding Affinity and Uptake by KB and Breast Cancer Cells The study evaluates cellulose nanocrystals (CNCs) as nanocarriers for targeted, intracellular delivery of molecular agents. CNCs were labeled with fluorescein-5'-isothiocyanate as an imaging agent and conjugated to folic acid (FA) as a targeting ligand. The CNC conjugates were characterized by UV-vis spectroscopy, ζ-potential analysis, dynamic light scattering, and atomic force microscopy. Cellular binding/uptake of the FA-conjugated CNCs by KB and MDA-MB-468 cells was quantified with cellular uptake assays. Internalization of the particles was confirmed by confocal microscopy. Uptake mechanisms were determined by inhibition studies with chlorpromazine and genistein. Binding affinity was qualitatively assessed with a free folate inhibition assay. Both KB and MDA-MB-468 cells exhibited significant and folate-receptor specific binding/uptake of FA-conjugated CNCs. Clathrin-mediated endocytosis was a significant uptake mechanism in both cell types, whereas caveolae-mediated endocytosis only played a significant role in MDA-MB-468 cells. Uptake inhibition of FA-conjugated CNCs by KB cells required high concentrations (>1 mM) of free FA. The observed FR-specific internalization of FA-conjugated CNCs by FR-positive cancer cells and tumors and their remarkable high affinity for the FR demonstrate the great potential of CNCs as novel nanocarriers for imaging agents and chemotherapeutics in the early detection and treatment of cancer. Endocytosis ; Internalization ; Nanocarriers ; Folate receptor ; Chemistry ; Conjugated system ; Confocal microscopy ; Fluorescein isothiocyanate ; Cancer cell ; Receptor-mediated endocytosis ; Biophysics ; Biochemistry ; Drug delivery ; Cell ; Cell biology ; Biology ; Cancer ; Fluorescence Advanced Cellulose Research Studies ; Polysaccharides and Plant Cell Walls
Authors: Ummarah Kanwal | Nadeem Irfan Bukhari | Nosheen Fatima Rana | Mehreen Rehman | Khalid Hussain | Nasir Abbas | Arshad Mehmood | Abida Raza
Source: International Journal of Nanomedicine (article, 2018-12-01)
Field: Materials Science — Biomaterials

Doxorubicin-loaded quaternary ammonium palmitoyl glycol chitosan polymeric nanoformulation: uptake by cells and organs The features of nanoformulation, ie, small particle size, sustained drug release, and enhanced cellular uptake, potential to target tumor passively coupled with the possibility of monitoring of tumor localization by optical imaging may make DOX-GCPQ an efficient nanotheranostic system. Zeta potential ; Doxorubicin ; Chitosan ; Biodistribution ; Cytotoxicity ; Materials science ; Nuclear chemistry ; MTT assay ; Particle size ; Biophysics ; Dynamic light scattering ; Dispersity ; Chemistry ; In vitro ; Nanotechnology ; Nanoparticle ; Biochemistry ; Polymer chemistry ; Medicine ; Biology ; Chemotherapy Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; Polymer Surface Interaction Studies