jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Louise J. Gourlay | Marco Mangiagalli | Elisabetta Moroni | Marina Lotti | Marco Nardini
Source: FEBS Journal (article, 2024-02-23)
Field: Materials Science — Materials Chemistry

Structural determinants of cold activity and glucose tolerance of a family 1 glycoside hydrolase ( <scp>GH1</scp> ) from Antarctic <i>Marinomonas</i> sp. ef1 Cold-active enzymes support life at low temperatures due to their ability to maintain high activity in the cold and can be useful in several biotechnological applications. Although information on the mechanisms of enzyme cold adaptation is still too limited to devise general rules, it appears that very diverse structural and functional changes are exploited in different protein families and within the same family. In this context, we studied the cold adaptation mechanism and the functional properties of a member of the glycoside hydrolase family 1 (GH1) from the Antarctic bacterium Marinomonas sp. ef1. This enzyme exhibits all typical functional hallmarks of cold adaptation, including high catalytic activity at 5 °C, broad substrate specificity, low thermal stability, and higher lability of the active site compared to the overall structure. Analysis of the here-reported crystal structure (1.8 Å resolution) and molecular dynamics simulations suggest that cold activity and thermolability may be due to a flexible region around the active site (residues 298-331), whereas the dynamic behavior of loops flanking the active site (residues 47-61 and 407-413) may favor enzyme-substrate interactions at the optimal temperature of catalysis (T<sub>opt</sub>) by tethering together protein regions lining the active site. Stapling of the N-terminus onto the surface of the β-barrel is suggested to partly counterbalance protein flexibility, thus providing a stabilizing effect. The tolerance of the enzyme to glucose and galactose is accounted for by the presence of a "gatekeeping" hydrophobic residue (Leu178), located at the entrance of the active site. Glycoside hydrolase ; Biology ; Hydrolase ; Glycoside ; Biochemistry ; Chemistry ; Enzyme ; Botany Enzyme Structure and Function ; Protein Structure and Dynamics ; Algal biology and biofuel production
Authors: Guillaume Bastien | Lukáš Severa | Martin Škuta | Carina Santos | Jiří Rybáček | Veronika Šolı́nová | Ivana Cı́sařová | Václav Kašička | Jiřı́ Kaleta
Source: Chemistry - A European Journal (article, 2024-09-16)
Field: Chemistry — Organic Chemistry

Triptycene‐Based Tripodal Molecular Platforms Molecular platforms are essential components of various surface-mounted molecular devices. Here, we document the synthesis of two universal triptycene-based tripodal pedestals featuring terminal alkynes in the axial position. We showcase their versatility by incorporating them into the structures of diverse functional molecules such as unidirectional light-driven molecular motors, photoswitches, and Brownian molecular rotors using standard cross-coupling reactions. We also present their fundamental physical properties, including acidity constants, data from differential scanning calorimetry, and crystallographic analysis of two parent and five derived structures. Finally, and importantly, we demonstrate that the photochemical properties of selected photoswitch representatives remain uncompromised when fused with tripods. Triptycene ; Chemistry ; Organic chemistry Supramolecular Chemistry and Complexes ; Molecular Junctions and Nanostructures ; Luminescence and Fluorescent Materials
Authors: Jiří Kalmár | František Karlický
Source: Journal of Applied Physics (preprint, 2024-06-26)
Field: Materials Science — Materials Chemistry

Strain-induced changes of electronic and optical properties of Zr-based MXenes Zr-based MXenes recently attracted attention because of its experimental preparation showing temperature stability, mechanical strength, and promising energy, sensoric, and electrochemistry applications. However, necessary theoretical predictions at a precise/predictive level are complicated due to essential excitonic features and strong electron correlation (i.e., a necessity to go beyond standard density functional theory, DFT). Contrary to the prevailing focus on oxygen-terminated MXenes and standard predictions of other Zr-based MXenes as conductors, based on the hybrid DFT and GW many-body perturbational theory, we were able to find seven different semiconductors (five of them for their equilibrium geometry and two others under slight tensile biaxial strain) in the case of two- and three-layered Zr2CT2 and Zr3C2T2 configurations with various terminations (T = O, F, S, Cl). We observed semiconductor-to-conductor transition induced by strain in the majority of such Zr-based MXenes at an experimentally achievable strain range. Furthermore, using the Bethe–Salpeter equation (BSE), we demonstrated that selected semiconducting Zr-based MXenes possess high optical absorption efficiency (20%–30%) in the visible light range, underscoring their potential in photonic applications. The high sensitivity of Zr-based MXenes to external conditions and functionalization combined with the thermal stability makes the materials promising for applications at operational temperatures in electronic and optical technologies. MXenes ; Strain (injury) ; Materials science ; Nanotechnology ; Medicine ; Internal medicine MXene and MAX Phase Materials ; 2D Materials and Applications ; Ferroelectric and Negative Capacitance Devices
Authors: Jingjing Ru | Bing Zhao | Fan Guang Zeng | Feiyun Guo | Jinhua Liu | Jianzhong Chen
Source: Frontiers of Optoelectronics (article, 2024-09-04)
Field: Materials Science — Materials Chemistry

Dual-functional application of Ca2Ta2O7:Bi3+/Eu3+ phosphors in multicolor tunable optical thermometry and WLED Abstract A series of Bi 3+ /Eu 3+ co-doped Ca 2 Ta 2 O 7 (CTO:Bi 3+ /Eu 3+ ) phosphors were prepared by high-temperature solid-state method for dual-emission center optical thermometers and white light-emitting diode (WLED) device. By modulating the doping ratio of Bi 3+ /Eu 3+ and utilizing the energy transfer from Bi 3+ to Eu 3+ , the tunable color emission ranging from green to reddish-orange was realized. The designed CTO:0.04Bi 3+ /Eu 3+ optical thermometers exhibit significant thermochromism, superior stability, and repeatability, with maximum sensitivities of S a = 0.055 K −1 (at 510 K) and S r = 1.298% K −1 (at 480 K) within the temperature range of 300−510 K, owing to the different thermal quenching behaviors between Bi 3+ and Eu 3+ ions. These features indicate the potential application prospects of the prepared samples in visualized thermometer or high-temperature safety marking. Furthermore, leveraging the excellent zero-thermal-quenching performance, outstanding acid/alkali resistance, and color stability of CTO:0.04Bi 3+ /0.16Eu 3+ phosphor, a WLED device with a high R a value of 95.3 has been realized through its combination with commercially available blue and green phosphors, thereby demonstrating the potential application of CTO:0.04Bi 3+ /0.16Eu 3+ in near-UV pumped WLED devices. Graphical abstract Phosphor ; Materials science ; Thermometer ; Thermal stability ; Doping ; Color temperature ; Diode ; Optoelectronics ; Analytical Chemistry (journal) ; Chemistry ; Physics Luminescence Properties of Advanced Materials ; Gas Sensing Nanomaterials and Sensors ; Perovskite Materials and Applications
Authors: Yin Yin | Nelmary Roas‐Escalona | Markus B. Linder
Source: Advanced Materials Interfaces (article, 2024-01-02)
Field: Materials Science — Biomaterials

Molecular Engineering of a Spider Silk and Mussel Foot Hybrid Protein Gives a Strong and Tough Biomimetic Adhesive Abstract High performance bio‐based materials are an important part of future sustainable technology, and engineered proteins provide excellent possibilities as functional polymers. Adhesives are widely needed for composite materials and biomimetic structures. In biological adhesives, two features have emerged as especially interesting—the role of coacervation and the presence of 3,4‐dihydroxyphenylalanine (DOPA). To study these, protein engineering is used to construct a hybrid silk‐mussel foot protein (mfp) adhesive. Tyr residues in the purified mfp are oxidized to DOPA and an encoded SpyCatcher‐Tag system allowed easy click‐chemistry to couple silk and mfp and to study the parts separately. The combined silk‐mfp protein have a strong tendency to coacervate. DOPA affected the properties of coacervates and increased adhesion by several ways of measuring. In lap shear testing, the combined mfp‐silk protein is superior to any of the components studied separately. Coacervation is suggested to contribute to the adhesion of silk‐mfp, and shows several features suggested to lead to the strength and toughness of natural adhesives. In the lap shear system, coacervation have a stronger overall effect on adhesion than the presence of DOPA. The results show that protein design provides a route toward high performance biosynthetic polymers and future sustainable materials. SILK ; Coacervate ; Spider silk ; Adhesive ; Polymer science ; Materials science ; Adhesion ; Byssus ; Toughness ; Polymer ; Nanotechnology ; Polyurethane ; Composite material ; Mussel ; Chemistry ; Biology ; Layer (electronics) ; Biochemistry Silk-based biomaterials and applications ; Biochemical and Structural Characterization ; Adhesion, Friction, and Surface Interactions
Authors: Pedro M. Resende | Florian Le Goupil | Guillaume Fleury | Georges Hadziioannou
Source: Physical Review Applied (article, 2024-05-09)
Field: Materials Science — Materials Chemistry

Solid-state electrocaloric cooler controlled by a thermal switch Refrigeration systems based on electrocaloric materials are considered as potential alternatives for the current vapor compression--based devices. These systems offer efficiencies closer to the Carnot limits, while also being compatible with miniaturization, compactness, and integration into electronics and wearables. Several prototypes have been proposed that mostly rely on mechanical and fluid motion for heat transfer, which prevent these systems from reaching higher operation frequency, good thermal contact, and low loss. Motionless electrocaloric solid-state devices have so far been conceptualized, but their relative complexity has hampered prototyping. In this work, we study the performance of a solid-state electrocaloric cooler that relies on thermoelectric switches to control heat flow. Our device operation mode minimizes energy consumption by absorbing heat passively through the heat switches. The applied currents, absorbed heat, power consumption, and coefficient of performance are assessed for a wide set of parameters following a steady-state heat propagation model, covering operation temperature, material properties, geometric features, frequency of operation, and material polarization losses. We show that a coefficient of performance (COP) above 1 can be obtained for temperature spans up to 6 K (for different material properties, geometry factors, or electrocaloric loss) and adiabatic temperature changes around 1 K higher than the applied temperature span. Higher temperature spans between 6 to 10 K yield a COP of the order of 0.1, leading to a significant increase in power consumption. These results are intended to guide research into these solid-state devices, in terms of choice of materials, temperatures, and geometry. Electrocaloric effect ; Thermal ; Materials science ; State (computer science) ; Solid-state ; Engineering physics ; Meteorology ; Optoelectronics ; Computer science ; Physics Ferroelectric and Piezoelectric Materials ; Magnetic and transport properties of perovskites and related materials ; Multiferroics and related materials
Authors: Kristina Lundgren | Octav Caldararu | Esko Oksanen | Ulf Ryde
Source: IUCrJ (article, 2024-09-30)
Field: Chemistry — Inorganic Chemistry

Quantum refinement in real and reciprocal space using the <i>Phenix</i> and <i>ORCA</i> software X-ray and neutron crystallography, as well as cryogenic electron microscopy (cryo-EM), are the most common methods to obtain atomic structures of biological macromolecules. A feature they all have in common is that, at typical resolutions, the experimental data need to be supplemented by empirical restraints, ensuring that the final structure is chemically reasonable. The restraints are accurate for amino acids and nucleic acids, but often less accurate for substrates, inhibitors, small-molecule ligands and metal sites, for which experimental data are scarce or empirical potentials are harder to formulate. This can be solved using quantum mechanical calculations for a small but interesting part of the structure. Such an approach, called quantum refinement, has been shown to improve structures locally, allow the determination of the protonation and oxidation states of ligands and metals, and discriminate between different interpretations of the structure. Here, we present a new implementation of quantum refinement interfacing the widely used structure-refinement software Phenix and the freely available quantum mechanical software ORCA. Through application to manganese superoxide dismutase and V- and Fe-nitrogenase, we show that the approach works effectively for X-ray and neutron crystal structures, that old results can be reproduced and structural discrimination can be performed. We discuss how the weight factor between the experimental data and the empirical restraints should be selected and how quantum mechanical quality measures such as strain energies should be calculated. We also present an application of quantum refinement to cryo-EM data for particulate methane monooxygenase and show that this may be the method of choice for metal sites in such structures because no accurate empirical restraints are currently available for metals. Quantum ; Software ; Neutron ; Computer science ; Physics ; Chemistry ; Quantum mechanics Metal-Catalyzed Oxygenation Mechanisms ; Metalloenzymes and iron-sulfur proteins ; Enzyme Structure and Function
Authors: Shengru Zhou | Chao Liang | Ziqi Mei | Rongbo Xie | Zhenci Sun | Ji Li | Wenqiang Zhang | Yong Ruan | Xiaoguang Zhao
Source: Micromachines (article, 2024-01-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Design and Implementation of a Flexible Electromagnetic Actuator for Tunable Terahertz Metamaterials Actuators play a crucial role in microelectromechanical systems (MEMS) and hold substantial potential for applications in various domains, including reconfigurable metamaterials. This research aims to design, fabricate, and characterize structures for the actuation of the EMA. The electromagnetic actuator overcomes the lack of high drive voltage required by other actuators. The proposed actuator configuration comprises supporting cantilever beams with fixed ends, an integrated coil positioned above the cantilever's movable plate, and a permanent magnet located beneath the cantilever's movable plate to generate a static magnetic field. Utilizing flexible polyimide, the fabrication process of the EMA is simplified, overcoming limitations associated with silicon-based micromachining techniques. Furthermore, this approach potentially enables large-scale production of EMA, with displacement reaching up to 250 μm under a 100 mA current, thereby expanding their scope of applications in manufacturing. To demonstrate the function of the EMA, we integrated it with a metamaterial structure to form a compact, tunable terahertz absorber, demonstrating a potential for reconfigurable electromagnetic space. Actuator ; Cantilever ; Microelectromechanical systems ; Metamaterial ; Terahertz radiation ; Surface micromachining ; Fabrication ; Materials science ; Voltage ; Magnet ; Electromagnetic coil ; Planar ; Optoelectronics ; Electrical engineering ; Electronic engineering ; Engineering ; Computer science Metamaterials and Metasurfaces Applications ; Energy Harvesting in Wireless Networks ; Microwave Engineering and Waveguides
Authors: Junais Habeeb Mokkath
Source: ChemPhysChem (article, 2024-01-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Plasmon induced hot carrier distribution in Ag<sub>20</sub>‐CO composite The interaction between plasmons and the molecules leads to the transfer of plasmon-induced hot carriers, presenting innovative opportunities for controlling chemical reactions on sub-femtosecond timescales. Through real-time time-dependent density functional theory simulations, we have investigated the enhancement of the electric field due to plasmon excitation and the subsequent generation and transfer of plasmon-induced hot carriers in a linear atomic chain of Ag<sub>20</sub> and an Ag<sub>20</sub> -CO composite system. By applying a Gaussian laser pulse tuned to align with the plasmon frequency, we observe a plasmon-induced transfer of hot electrons from the occupied states of Ag to the unoccupied molecular orbitals of CO. Remarkably, there is a pronounced accumulation of hot electrons and hot holes on the C and O atoms. This phenomenon arises from the electron migration from the inter-nuclear regions of the C-O bond towards the individual C and O atoms. The insights garnered from our study hold the potential to drive advancements in the development of more efficient systems for catalytic processes empowered by plasmonic interactions. Plasmon ; Chemical physics ; Femtosecond ; Excitation ; Delocalized electron ; Electron transfer ; Electron ; Atomic physics ; Hot electron ; Molecular physics ; Density functional theory ; Atomic orbital ; Chemistry ; Chemical bond ; Electric field ; Materials science ; Laser ; Photochemistry ; Optoelectronics ; Computational chemistry ; Physics ; Optics Gold and Silver Nanoparticles Synthesis and Applications ; Nanocluster Synthesis and Applications ; nanoparticles nucleation surface interactions
Authors: Jianai Chen | Jin Liu | Liang Zeng | Guangsheng Dong | Xiaosong Guo | Mingjiao Sun | Haichao Liu | Yujie Dong | Cheng ZHANG | Weijun Li
Source: Advanced Optical Materials (article, 2024-09-30)
Field: Materials Science — Materials Chemistry

Temperature‐Dependent Reversible Afterglow Between Green, Orange, and Red in Dual‐Delay Organic Doped Material Abstract Achieving a wide‐range color‐tunable and dynamically long‐afterglow emission in a single‐doped system remains a challenge. In this study, a unique host‐guest doped material, TPA‐PTPQ/TPA, exhibits dual‐delay emission at 516 and 605 nm, both with long lifetimes of up to 108 and 145 ms, which derives from thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) mechanisms, respectively. Notably, this host‐guest material demonstrates a temperature‐dependent dynamically reversible afterglow characteristic, transitioning green, orange, and red with a substantial spectra shift of ≈90 nm under different temperature conditions. This phenomenon is due to the diverse temperature effect on TADF and RTP emissions. These remarkable luminescence properties are successfully applied in security checks and anti‐counterfeiting encryption. This study provides valuable insights into the design of dynamically reversible dual‐delay‐emissive long‐afterglow luminescent materials based on a host‐guest doping system. Afterglow ; Materials science ; Doping ; Orange (colour) ; Dual (grammatical number) ; Optoelectronics ; Optics ; Physics Luminescence and Fluorescent Materials ; Polydiacetylene-based materials and applications ; Organic Light-Emitting Diodes Research
Authors: Yuan‐Fong Chou Chau
Source: Nanomaterials (article, 2024-04-11)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Boosting Second Harmonic Generation Efficiency and Nonlinear Susceptibility via Metasurfaces Featuring Split-Ring Resonators and Bowtie Nanoantennas This work investigates a metasurface design to achieve remarkable second harmonic generation (SHG) conversion efficiency and enhance effective nonlinear susceptibility using the finite element method. The elements of the designed structure are composed of a rectangular split-ring resonator Ag film, a bowtie-shaped Ag nanoantenna, and a pair of Bi bars that induce nonlinear optical phenomena due to the nonuniform distribution of the electric and magnetic fields within the device surface. The simulation results agree perfectly with the theory and demonstrate outstanding achievements in terms of SHG conversion efficiency (<i>η</i>) and effective nonlinear susceptibility (χeff(2)). Specifically, the metasurface reaches a peak <i>η</i> value of 4.544×10-8 and an effective nonlinear susceptibility of 3.4×104 pm/V. This work presents a novel and versatile design to achieve high <i>η</i> and χeff(2) in an SHG metasurface. Resonator ; Second-harmonic generation ; Nonlinear system ; Energy conversion efficiency ; Nonlinear optics ; Harmonic ; Split-ring resonator ; Materials science ; Optoelectronics ; Optics ; Ring (chemistry) ; Finite element method ; Physics ; Acoustics ; Chemistry ; Quantum mechanics Metamaterials and Metasurfaces Applications ; Plasmonic and Surface Plasmon Research ; Advanced Antenna and Metasurface Technologies
Authors: Md Akram Ahmad | Pankaj Kumar | Bhubon Chandra Mech | Jitendra Kumar
Source: Scientific Reports (article, 2024-05-03)
Field: Materials Science — Materials Chemistry

Trade-off analysis between gm/ID and fT of GNR-FETs with single-gate and double-gate device structure This study examines the operational parameters of field-effect transistors (FETs) using single-gate (SG) and double-gate (DG) graphene nanoribbons (GNRs) within the analog/RF domain. A detailed exploration is conducted through an atomistic p<sub>z</sub> orbital model, derived from the Hamiltonian of graphene nanoribbons, employing the nonequilibrium Green's function formalism (NEGF) for analysis. The atomic characteristics of the GNRFETs channel are accurately described by utilizing a tight-binding Hamiltonian with an atomistic p<sub>z</sub> orbital basis set. The primary focus of the analysis revolves around essential analog/RF parameters such as transconductance, transconductance generation factor (TGF), output resistance, early voltage, intrinsic gain, gate capacitance, cut-off frequency, and transit time. Furthermore, the study assesses the gain frequency product (GFP), transfer frequency product (TFP), and gain transfer frequency product (GTFP) to evaluate the balance between transistor efficiency, gain, and cut-off frequency. The research outcomes indicate that double-gate GNRFETs exhibit superior analog/RF performance in comparison to their single-gate counterparts. However, both types of devices demonstrate cut-off frequencies in the gigahertz range. The extensive data presented in this study provides valuable insights into the characteristics of SG and DG GNRFETs, particularly in terms of the figure-of-merit (FoM) for analog/RF performance, offering a comprehensive analysis of the trade-offs in analog applications. In addition, the analysis has been extended be performing a high-performance hybrid 6T static random-access memory (SRAM) to get the impact in their circuit level variation as well as improvement in their circuit performance. Transconductance ; Transistor ; Capacitance ; Gain–bandwidth product ; Physics ; Field-effect transistor ; Optoelectronics ; Figure of merit ; Materials science ; Electronic engineering ; Voltage ; CMOS ; Amplifier ; Operational amplifier ; Engineering ; Quantum mechanics Graphene research and applications ; Quantum and electron transport phenomena ; Advancements in Semiconductor Devices and Circuit Design