jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Georg Zagler | Michele Reticcioli | Clemens Mangler | Daniel Scheinecker | Cesare Franchini | Jani Kotakoski
Source: 2D Materials (article, 2020-06-12)
Field: Materials Science — Materials Chemistry

CuAu, a hexagonal two-dimensional metal Growth of two-dimensional metals has eluded materials scientists since the discovery of the atomically thin graphene and other covalently bound 2D materials. Here, we report a two-atom-thick hexagonal copper-gold alloy, grown through thermal evaporation on freestanding graphene and hexagonal boron nitride. The structures are imaged at atomic resolution with scanning transmission electron microscopy and further characterized with spectroscopic techniques. While the 2D structures are stable over months in vacuum, electron irradiation in the microscope provides sufficient energy to cause a phase transformation-atoms are released from their lattice sites with the gold atoms eventually forming face-centered cubic nanoclusters on top of 2D regions during observation. The presence of copper in the alloy enhances sticking of gold to the substrate, which has clear implications for creating atomically thin electrodes for applications utilizing 2D materials. Its practically infinite surface-to-bulk ratio also makes the 2D CuAu particularly interesting for catalysis applications. Hexagonal crystal system ; Metal ; Materials science ; Crystallography ; Condensed matter physics ; Geology ; Metallurgy ; Chemistry ; Physics Graphene research and applications ; ZnO doping and properties ; Copper-based nanomaterials and applications
Authors: Marina Kurbasic | Evelina Parisi | Ana M. García | Silvia Marchesan
Source: Current Topics in Medicinal Chemistry (review, 2020-03-16)
Field: Materials Science — Biomaterials

Self-Assembling, Ultrashort Peptide Gels as Antimicrobial Biomaterials Supramolecular antimicrobial hydrogels based on peptides are attractive soft materials for the treatment of infections, considering their ease of preparation and benign fate in biological settings and in the environment. In particular, stimuli-responsive systems that can be assembled/disassembled ad hoc could offer the opportunity to switch on/off their bioactivity as needed. Besides, the shorter is the peptide, the lower its cost of production. However, a structure-to-function relationship is yet to be defined and reported activities are generally not yet competitive relative to traditional antibiotics. Inspiration for their design can be found in host defense peptides (HDPs), which can self-assemble to exert their function. This article reviews research developments in this emerging area, and it examines features, differences and similarities between antimicrobial and amyloid peptides to open the avenue towards the next generation of supramolecular antimicrobial peptides as innovative therapeutic materials. Antimicrobial ; Self-healing hydrogels ; Supramolecular chemistry ; Peptide ; Antimicrobial peptides ; Nanotechnology ; Function (biology) ; Chemistry ; Self-assembling peptide ; Combinatorial chemistry ; Materials science ; Biochemistry ; Biology ; Cell biology ; Molecule ; Organic chemistry Supramolecular Self-Assembly in Materials ; Antimicrobial Peptides and Activities ; Polydiacetylene-based materials and applications
Authors: Kyu Myung Lee | Philipp Le | Stephan A. Sieber | Stephan M. Hacker
Source: Chemical Communications (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Degrasyn exhibits antibiotic activity against multi-resistant<i>Staphylococcus aureus</i>by modifying several essential cysteines Degrasyn inhibits deubiquitination enzymes and has anti-cancer activity. We here show that it also exhibits antimicrobial activity against multi-resistant Staphylococcus aureus. Structure activity relationship studies demonstrate an important role of the electrophilic α-cyanoacrylamide moiety as a Michael acceptor. A suite of chemical proteomic techniques unraveled binding of this moiety to various cysteine residues of essential proteins in a reversibly covalent manner. Staphylococcus aureus ; Antibiotics ; Mode of action ; Chemistry ; Microbiology ; Bacteria ; Biology ; Biochemistry ; Genetics Click Chemistry and Applications ; Antimicrobial Peptides and Activities ; Antimicrobial Resistance in Staphylococcus
Authors: A. Mariscal | Aitana Tarazaga Martín-Luengo | B. Galiana | C. Ballesteros | A. Bonanni | Javier Martín‐Sánchez | R. Serna
Source: The Journal of Physical Chemistry C (article, 2020-06-16)
Field: Materials Science — Materials Chemistry

Photoluminescence and Stoichiometry Correlation in Nanocrystalline EuO<i><sub>x</sub></i> Thin Films: Tunable Color Emission The development of broadband and ultracompact optoelectronic devices relies on the possibility of fabricating bright and tunable emitters at the nanoscale. Here, we show emission from EuO <i><sub>x</sub></i> (1 ≤ <i>x</i> < 1.4) thin films on silicon formed by nanocrystals with average sizes in the range of 5 nm. The photoluminescence emission of the nano-EuO <i><sub>x</sub></i> films is tunable as a function of the oxygen concentration changing from a green broadband Eu<sup>2+</sup>-related emission to a narrow red Eu<sup>3+</sup>-related emission. To reach these results has been instrumental through the use of a new methodology specially designed to achieve high-quality europium oxide films whose compositional properties are controlled by the growth base pressure and preserved thanks to a chemically stable and transparent cover layer of Al<sub>2</sub>O<sub>3</sub>. Our findings confirm the outstanding potential of nanostructured EuO <i><sub>x</sub></i> films as "one-compound" optical elements with tunable emission properties for their implementation in integrated silicon-based devices. Photoluminescence ; Materials science ; Nanocrystalline material ; Optoelectronics ; Thin film ; Europium ; Stoichiometry ; Silicon ; Luminescence ; Nanotechnology ; Analytical Chemistry (journal) ; Chemistry ZnO doping and properties ; Semiconductor materials and devices ; Silicon Nanostructures and Photoluminescence
Authors: Mélanie Auffan | Catherine Santaella | Lenka Brousset | Marie Tella | Elise Morel | Philippe Ortet | M. M. Barakat | Corinne Chanéac | Julien Issartel | Bernard Angeletti | Clément Levard | Jean‐Louis Hazemann | Mark R. Wiesner | Jérôme Rose | Alain Thiéry | Jean-Yves Bottero
Source: Environmental Science Nano (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

The shape and speciation of Ag nanoparticles drive their impacts on organisms in a lotic ecosystem Silver nanomaterials with different shapes (spheres, plates, wires, rods, cubes) are valued by industries and scientists for their shape-dependent properties which make them useful for diverse applications. Nanomaterials ; River ecosystem ; Genetic algorithm ; Rod ; Ecosystem ; Nanoparticle ; Nanotechnology ; Materials science ; Silver nanoparticle ; Environmental science ; Ecology ; Biology Nanoparticles: synthesis and applications ; Laser-Ablation Synthesis of Nanoparticles ; Quantum Dots Synthesis And Properties
Authors: Ganesan Karuppiah | C. Kailasanathan | Murugesan Palaniappan | Carlo Santulli | Sivasubramanian Palanisamy
Source: Molecules (article, 2020-11-27)
Field: Materials Science — Polymers and Plastics

Multiobjective Optimization of Fabrication Parameters of Jute Fiber/Polyester Composites with Egg Shell Powder and Nanoclay Filler In the present study, a model is presented to optimize the fabrication parameters of natural fiber reinforced polyester matrix composites with dual fillers. In particular, jute fiber mat was chosen as reinforcement and eggshell powder (ESP) and montmorillonite nanoclay (NC) were selected as fillers. The weight per square meter (GSM) of the fiber, the weight percentage of ESP and NC have been chosen as independent variables and the influence of these variables on tensile, flexural and impact strength of the composite has been inspected. The permutations of the different combinations of factors are intended to accomplish higher interfacial strength with the lowest possible number of tested specimens. The experiments were designed by the Taguchi strategy and a novel multi-objective optimization technique named COPRAS (COmplex PRoportional ASsessment of alternatives) was used to determine the optimal parameter combinations. Affirmation tests were performed with the optimal parameter settings and the mechanical properties were evaluated and compared. Experimental results show that fiber GSM and eggshell powder content are significant variables that improve mechanical strength, while the nanoclay appears less important. Composite material ; Materials science ; Ultimate tensile strength ; Taguchi methods ; Fiber ; Composite number ; Flexural strength ; Fabrication ; Filler (materials) ; Natural fiber ; Eggshell ; Izod impact strength test ; Polyester ; Orthogonal array ; Shell (structure) ; Wood flour Natural Fiber Reinforced Composites ; Mechanical Engineering and Vibrations Research ; Tribology and Wear Analysis
Authors: Chao Duan | Weihua Li | Rui Wang
Source: The Journal of Chemical Physics (article, 2020-08-10)
Field: Chemistry — Physical and Theoretical Chemistry

Conformation of a single polyelectrolyte in poor solvents Understanding the conformation of a polyelectrolyte (PE) is not only a fundamental challenge in polymer science but also critical for understanding the folding and aggregation of proteins. Here, we develop a theory by systematically including the electrostatic interactions into the self-consistent field theory for polymers to study the conformational behaviors of a single PE in poor solvents. As the backbone charge fraction of the PE increases, our theory predicts that the spherical globule (Sph) can either be elongated to a series of pearl-necklace (PN) structures or be flattened to two novel structures that have not been reported before: biconcave red cell and toroid. While the PN structures are stable conformations, the two fattened structures are metastable. We find that the cylindrical globule, the stability of which is under debate, is an unstable structure. The signature of the PN structures obtained by our calculation is less pronounced than that reported by other theoretical works due to the continuous change in the curvature from the pearl to the necklace, which, however, is in good agreement with the results from molecular simulations and neutron scattering experiments. In addition, our theory reveals different characteristics of the globule to PN transition: the transition from the Sph to the PN with double pearls is discontinuous, whereas those from adjacent PN structures are continuous at finite salt concentrations. Furthermore, we observe different scaling behaviors: the string width is not a constant as a thermal blob but decays as the backbone charge fraction increases. Polyelectrolyte ; Chemical physics ; Polymer ; Metastability ; Crystallography ; Folding (DSP implementation) ; Chemistry ; Curvature ; Scaling ; Charge (physics) ; Electrostatics ; Materials science ; Physics ; Physical chemistry Electrostatics and Colloid Interactions ; Material Dynamics and Properties ; Polymer Surface Interaction Studies
Authors: Jana Schiller | Eugenia V. Peresypkina | A.V. Virovets | Manfred Scheer
Source: Angewandte Chemie International Edition (article, 2020-04-24)
Field: Chemistry — Inorganic Chemistry

Metal‐Deficient Supramolecule Based on a Fivefold‐Symmetric Building Block An unprecedented cationic supramolecule [(Cp''Fe(η<sup>5</sup> -P<sub>5</sub> ))<sub>12</sub> {CuNCMe}<sub>8</sub> ]<sup>8+</sup> 2.66 nm in diameter was selectively isolated as a salt of the weakly coordinating anion [Al{OC(CF<sub>3</sub> )<sub>3</sub> }<sub>4</sub> ]<sup>-</sup> for the first time and characterized by X-ray structure analysis, PXRD, NMR spectroscopy, and mass spectrometry. Its metal-deficient core contains the lowest possible number of Cu atoms to connect 12 pentaphosphaferrocene units, providing a supramolecule with fullerene topology which, topologically, also represents the simplest homologue in the family of metal-deficient pentaphosphaferrocene-based supramolecules [{Cp<sup>R</sup> Fe(η<sup>5</sup> -P<sub>5</sub> )}<sub>12</sub> (CuX)<sub>20-n</sub> ]. The 12 vacant metal sites between the cyclo-P<sub>5</sub> rings, the largest number attained to date, make this compound a facile precursor for potential inner and outer modifications of the core as well as for functionalization via the substitution of labile acetonitrile ligands. Cationic polymerization ; Acetonitrile ; Crystallography ; Metal ; Salt (chemistry) ; Fullerene ; Chemistry ; Nuclear magnetic resonance spectroscopy ; Inner core ; Stereochemistry ; Materials science ; Polymer chemistry ; Organic chemistry Synthesis and characterization of novel inorganic/organometallic compounds ; Organometallic Complex Synthesis and Catalysis ; Inorganic Chemistry and Materials
Authors: Matteo Faltracco | Verena Sukowski | Max van Druenen | Trevor A. Hamlin | F. Matthias Bickelhaupt | Eelco Ruijter
Source: The Journal of Organic Chemistry (article, 2020-06-25)
Field: Chemistry — Organic Chemistry

Diastereoselective Synthesis of β-Lactams by Ligand-Controlled Stereodivergent Intramolecular Tsuji–Trost Allylation The diastereoselective synthesis of highly substituted β-lactams by intramolecular Tsuji-Trost allylation is reported. Judicious selection of the ligand on palladium allows selective access to either the <i>trans</i> isomer (in generally good to excellent yield with very high diastereomeric excess) or <i>cis</i> isomer (with yields and diastereoselectivity ranging from modest to excellent depending on the substrate). The reaction proceeds under exceedingly mild conditions (rt, no additives) with a broad range of substrates, which are readily accessible by the Ugi reaction. Intramolecular force ; Ligand (biochemistry) ; Stereochemistry ; Chemistry ; Receptor ; Biochemistry Synthesis and Catalytic Reactions ; Synthesis of β-Lactam Compounds ; Synthetic Organic Chemistry Methods
Authors: Stephen Carr | Daniel Massatt | Mitchell Luskin | Efthimios Kaxiras
Source: Physical Review Research (article, 2020-07-29)
Field: Materials Science — Materials Chemistry

Duality between atomic configurations and Bloch states in twistronic materials In this work, crystal momentum and atomic stacking configuration are introduced as dual variables in electronic moir\'e systems. Within the context of this duality, the authors explain the microscopic origins of several twistronic spectral features and provide multiple approaches for predicting them in new materials. Context (archaeology) ; Duality (order theory) ; Crystal (programming language) ; Dual (grammatical number) ; Stacking ; Momentum (technical analysis) 2D Materials and Applications ; Topological Materials and Phenomena ; Graphene research and applications
Authors: Sebastian Meyer | Zhi Yang Tan | Dmitry N. Chigrin
Source: Nanophotonics (article, 2020-02-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Multiphysics simulations of adaptive metasurfaces at the meta‐atom length scale Abstract Adaptive metasurfaces (MSs) provide immense control over the phase, amplitude and propagation direction of electromagnetic waves. Adopting phase‐change materials (PCMs) as an adaptive medium allows us to tune functionality of MSs at the meta‐atom length scale providing full control over MS (re‐)programmability. Recent experimental progress in the local switching of PCM‐based MSs promises to revolutionize adaptive photonics. Novel possibilities open new challenges, one of which is a necessity to understand and be able to predict the phase transition behavior at the sub‐micrometer scale. A meta‐atom can be switched by a local deposition of heat using optical or electrical pulses. The deposited energy is strongly inhomogeneous and the resulting phase transition is spatially non‐uniform. The drastic change of the material properties during the phase transition leads to time‐dependent changes in the absorption rate and heat conduction near the meta‐atom. These necessitate a self‐consistent treatment of electromagnetic, thermal and phase transition processes. Here, a self‐consistent multiphysics description of an optically induced phase transition in MSs is reported. The developed model is used to analyze local tuning of a perfect absorber. A detailed understanding of the phase transition at the meta‐atom length scale will enable a purposeful design of programmable adaptive MSs. Multiphysics ; Phase transition ; Atom (system on chip) ; Phase (matter) ; Photonics ; Materials science ; Absorption (acoustics) ; Length scale ; Nanophotonics ; Optoelectronics ; Thermal ; Nanotechnology ; Computational physics ; Computer science ; Physics ; Optics ; Condensed matter physics ; Mechanics ; Quantum mechanics ; Thermodynamics Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Liquid Crystal Research Advancements
Authors: Brice Saint-Michel | Valeria Garbin
Source: Current Opinion in Colloid & Interface Science (article, 2020-10-06)
Field: Materials Science — Materials Chemistry

Bubble dynamics for broadband microrheology of complex fluids Bubbles in complex fluids are often desirable, and sometimes simply inevitable, in the processing of formulated products. Bubbles can rise by buoyancy, grow or dissolve by mass transfer, and readily respond to changes in pressure, thereby applying a deformation to the surrounding complex fluid. The deformation field around a stationary, spherical bubble undergoing a change in radius is simple and localized, thus making it suitable for rheological measurements. This article reviews emerging approaches to extract information on the rheology of complex fluids by analysing bubble dynamics. The focus is on three phenomena: changes in radius by mass transfer, harmonic oscillations driven by an acoustic wave, and bubble collapse. These phenomena cover a broad range of deformation frequencies, from 10−4–106 Hz, thus paving the way to broadband microrheology using bubbles as active probes. The outstanding challenges that need to be overcome to achieve a robust technique are also discussed. Microrheology ; Bubble ; Rheology ; Complex fluid ; Deformation (meteorology) ; RADIUS ; Complex system ; Field (mathematics) Ultrasound and Cavitation Phenomena ; Microfluidic and Bio-sensing Technologies ; Ultrasound and Hyperthermia Applications
Authors: Agustín Apaolaza | D. Richard | M. R. Tejerina
Source: Processing and Application of Ceramics (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

Experimental and ab initio study of the structural and optical properties of ZnO coatings: Performance of the DFT+U approach In this work, ZnO coatings were produced by the spray-pyrolysis technique and characterized by scanning electron microscopy, X-ray diffraction and optical transmittance spectroscopy. The experimental results were compared to predictions obtained from electronic-structure calculations based on the Density Functional Theory plus U (DFT+U) approach. To this purpose, the 2H, 4H and 6H polytypes of ZnO were theoretically analysed, and DFT+U was assessed for the calculation of structural, electronic and optical properties of the hexagonal ZnO structures. We found that DFT+U is an effective and accurate method that combined with experimental measurements, allows a deeper insight about the coatings of the wurtzite (2H) phase synthesized in the laboratory. This comprehensive study of the pure ZnO is the first step towards the study of more complex ZnO-based coatings. Wurtzite crystal structure ; Materials science ; Density functional theory ; Transmittance ; Electronic structure ; Ab initio ; Hexagonal phase ; Spectroscopy ; Scanning electron microscope ; Hexagonal crystal system ; Computational chemistry ; Crystallography ; Optoelectronics ; Zinc ; Composite material ; Metallurgy ; Chemistry ; Organic chemistry ZnO doping and properties ; Magnetic and transport properties of perovskites and related materials ; Copper-based nanomaterials and applications
Authors: Anju Surendranath | P.V. Mohanan | J Zhou | A Kroll | M Holay | R Fang | L Zhang | X He | H Deng | H.-M Hwang | S Kargozar | M Mozafari | O Farokhzad | R Langer | A Mohs | J Provenzale | R Toy | L Bauer | C Hoimes | K Ghaghada | E Karathanasis | S Bryant | K Straker | C Wrigley | M Ahmadi | M Ghazvini | M Alhuyi Nazari | F Pourfayaz | G Lorenzini | T Ming | P Gore | A Purushothaman | M Naebe | X Wang | B Kandasubramanian | N Raina | P Sharma | P Slathia | D Bhagat | A Pathak | A Kahru | H.-C Dubourguier | S Wu | S Zhang | Y Gong | L Shi | B Zhou | G Tortella | O Rubilar | N Durn | M Diez | M Martnez | J Parada | A Seabra | P Shukla | P Chaurasia | K Younis | O Qadri | S Faridi | G Srivastava | T Zhang | Q Tan | X Yu | M Naderi | A Daneshshahraki | S Manjunatha | D Biradar | Y Aladakatti | O Sadik | A Zhou | S Kikandi | N Du | Q Wang | K Varner | S Pradhan | P Patra | S Das | S Chandra | S Mitra | K Dey | S Akbar | P Palit | A Goswami | T Prasad | P Sudhakar | Y Sreenivasulu | P Latha | V Munaswamy | K Reddy | T Sreeprasad | P Sajanlal | T Pradeep | L Zheng | F Hong | S Lu | C Liu | F Carmona | G Dal Sasso
Source: Biointerface Research in Applied Chemistry (article, 2020-10-31)
Field: Materials Science — Materials Chemistry

Impact of Nanoparticles in Balancing the Ecosystem Nanotechnology has contributed enormous breakthroughs in various scientific and engineering disciplines, from basic researches to advanced product development. Rapid advancements in nanotechnology have accomplished a great quantum leap in the areas of medicine, environment, agriculture, and renewable energy. As a result, there has been a growing interest to substitute conventional materials with nanomaterials in almost all scientific disciplines globally. This economic success has left behind the possibilities of critical adverse effects these materials can impart to the environment and its dependants. Several debates were ongoing worldwide on the effect of nanoparticle released metal ions and their subsequent toxicological impacts. It’s been anticipated that the increased application of nanoparticles will lead to abrupt unchecked emission of the same into various environmental strata. Therefore, despite these emerging advancements, the potential adverse effects these nanotechnological researchers can put forward also need a thorough investigation. This review article has highlighted the currently employed applications of engineered nanoparticles in agriculture technology and environmental restoration, adverse effects of its exposure to environmental flora and fauna, ecosystem toxicity, and related issues. Nanotechnology ; Agriculture ; Applications of nanotechnology ; Environmental science ; Ecology ; Materials science ; Biology Nanoparticles: synthesis and applications