jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Kejian Wang | Geoffroy Prévot | Jean‐Noël Aqua
Source: Scientific Reports (article, 2024-01-29)
Field: Materials Science — Materials Chemistry

Anomalous intralayer growth of epitaxial Si on Ag(111) The epitaxial growth of silicene has been the subject of many investigations, controversies and non-classical results. In particular, the initially promising deposition of Si on a metallic substrate such as Ag(111) has revealed unexpected growth modes where Si is inserted at the beginning of the growth in the first atomic plane of the substrate. In order to rationalize this anomalous growth mode, we develop an out-of-equilibrium description of a lattice-based epitaxial growth model, which growth dynamics are analyzed via kinetic Monte-Carlo simulations. This model incorporates several effects revealed by the experiments such as the intermixing between Si and Ag, and surface effects. It is parametrized thanks to an approach in which we show that relatively precise estimates of energy barriers can be deduced by meticulous analysis of atomic microscopy images. This analysis enables us to reproduce both qualitatively and quantitatively the anomalous growth patterns of Si on Ag(111). We show that the dynamics results in two modes, a classical sub-monolayer growth mode at low temperature, and an inserted growth mode at higher temperatures, where the deposited Si atoms insert in the first layer of the substrate by replacing Ag atoms. Furthermore, we reproduce the non-standard [Formula: see text] shape of the experimental plot of the island density as a function of temperature, with a shift in island density variation during the transition between the submonoloyer and inserted growth modes. Epitaxy ; Silicene ; Monolayer ; Substrate (aquarium) ; Kinetic Monte Carlo ; Island growth ; Materials science ; Kinetic energy ; Condensed matter physics ; Crystallography ; Monte Carlo method ; Silicon ; Physics ; Chemistry ; Layer (electronics) ; Nanotechnology ; Optoelectronics ; Mathematics ; Geology ; Quantum mechanics Graphene research and applications ; 2D Materials and Applications ; Ga2O3 and related materials
Authors: Daniel Rutstrom | Luis Stand | M. Kapusta | Dylan Windsor | Haixuan Xu | Charles L. Melcher | Mariya Zhuravleva
Source: Optical Materials X (article, 2024-08-31)
Field: Materials Science — Materials Chemistry

Impurity-enhanced core valence luminescence via Zn-doping in cesium magnesium chlorides Scintillators with faster timing capabilities are currently in high demand for use in radiation detection systems in the fields of nuclear and medical physics. The limited number of suitable materials that meet the performance criteria of next generation detection systems presents an opportunity for discovery of new fast scintillator materials. In this work, the effects of doping several ultrafast core-valence luminescent (CVL) scintillators with divalent Zn is explored. Three compounds are investigated – CsMgCl 3 , Cs 2 MgCl 4 , and Cs 3 MgCl 5 – and single crystals of each doped with 5 mol% Zn are grown via the Bridgman method. Additionally, mixing across the full range of concentrations (from 0 % to 100 % Zn) is explored in the Cs 2 Mg 1-x Zn x Cl 4 and Cs 3 Mg 1-x Zn x Cl 5 systems. For low concentrations of Zn, light yields of all three compounds are enhanced (by up to ∼60 %) compared to the pure crystals, achieving what we believe to be the brightest known CVL, CsMgCl 3 :Zn 5 % (3400 ± 170 ph/MeV light yield). More importantly, Zn doping does not affect the ultrafast timing properties, with each composition maintaining a single-component decay time around 1–3 ns. A sub-100 ps coincidence time resolution (CTR) is also achieved with CsMgCl 3 :Zn 5 %. The results of this work reveal a new avenue towards obtaining brighter CVL materials, which could open up possibilities for more advanced ultrafast scintillators to be discovered moving forward. • A new strategy for improving scintillation light yield and timing performance of CVL materials is revealed. • Single crystals of undoped and Zn-doped CsMgCl 3 , Cs 2 MgCl 4 , and Cs 3 MgCl 5 were grown by the vertical Bridgman method. • Light yield at 662 keV increases by up to 60 % upon doping with 5 mol% Zn. • Slow decay components are not introduced with Zn doping. Impurity ; Valence (chemistry) ; Magnesium ; Doping ; Caesium ; Luminescence ; Inorganic chemistry ; Materials science ; Chemistry ; Radiochemistry ; Metallurgy ; Organic chemistry ; Optoelectronics Luminescence Properties of Advanced Materials ; Radiation Detection and Scintillator Technologies ; Nuclear materials and radiation effects
Authors: Inayat Ullah Irshad | Ajeet K. Sharma
Source: Biophysical Journal (article, 2024-09-13)
Field: Materials Science — Materials Chemistry

Understanding the regulation of protein synthesis under stress conditions Stress (linguistics) ; Chemistry ; Computational biology ; Biophysics ; Biology ; Philosophy ; Linguistics Enzyme Structure and Function ; Biochemical and Molecular Research ; Viral Infectious Diseases and Gene Expression in Insects
Authors: Jelena Todorović | I. Swapna | Antonio Suma | Vincenzo Carnevale | Harold H. Zakon
Source: Biophysical Journal (article, 2024-03-01)
Field: Chemistry — Electrochemistry

Dual mechanisms contribute to enhanced voltage dependence of an electric fish potassium channel Potassium ; Voltage ; Potassium channel ; Voltage-gated potassium channel ; Fish <Actinopterygii> ; Electric fish ; Channel (broadcasting) ; Voltage-gated ion channel ; Chemistry ; Materials science ; Biophysics ; Electrical engineering ; Biology ; Ion channel ; Fishery ; Biochemistry ; Engineering Electrochemical Analysis and Applications ; Fish biology, ecology, and behavior ; Photoreceptor and optogenetics research
Authors: Wentao Yue | Jun Shan | Runxian Jiao | Lichuan Zhang | Yuanping Chen | Hao Dong
Source: Applied Sciences (article, 2024-09-19)
Field: Materials Science — Materials Chemistry

Strain-Controlled Electronic and Magnetic Properties of Janus Nitride MXene Monolayer MnCrNO2 Two-dimensional (2D) van der Waals (vdW) magnetic materials show potential for the advancement of high-density, energy-efficient electronic and spintronic applications in future memory and computation. Here, by using first-principles density functional theory (DFT) calculations, we predict a new 2D Janus nitride MXene MnCrNO2 monolayer. Our results suggest that the optimized MnCrNO2 monolayer possesses a hexagonal structure and exhibits good dynamical stability. The intrinsic monolayer MnCrNO2 exhibits semiconductive properties and adopts a ferromagnetic ground state with an out-of-plane easy axis. It can sustain strain effects within a wide range of strains from −10% to +8%, as indicated by the phonon dispersion spectra. Under the biaxial tensile strain, a remarkable decrease in the bandgap of the MnCrNO2 is induced, which is attributed to the distinct roles played by Mn and Cr in the VBM or CBM bands. Furthermore, when the compressive strain reaches approximately −8%, the magnetic anisotropy undergoes a transition from an out-of-plane easy axis to an in-plane easy axis. This change is mainly influenced by the efficient hybridization of the d orbitals, particularly in Mn atoms. Our study of the Janus MXene MnCrNO2 monolayer indicates its potential as a promising candidate for innovative electronic and spintronic devices; this potential is expected to create interest in its synthesis. Janus ; Materials science ; Monolayer ; Condensed matter physics ; Nanotechnology ; Physics MXene and MAX Phase Materials ; 2D Materials and Applications ; Ferroelectric and Negative Capacitance Devices
Authors: Gordon C. Younkin | Martin L. Alani | Tobias Züst | Georg Jander
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2024-04-11)
Field: Materials Science — Biomaterials

Four enzymes control natural variation in the steroid core of <i>Erysimum</i> cardenolides Plants use an array of toxic compounds to defend themselves from attack against insects and other herbivores. One mechanism through which plants may evolve more toxic compounds is through modifications to the structure of compounds they already produce. In this study, we show how plants in the wallflower genus <i>Erysimum</i> use four enzymes to fine-tune the structure of toxic metabolites called cardenolides. Natural variation in the sequence and expression of a single enzyme called progesterone 5β-reductase 2 partly explains the variation in cardenolides observed across the <i>Erysimum</i> genus. These alterations to cardenolide structure over the course of evolution suggests that there may be context-dependent benefits to <i>Erysimum</i> to invest in one cardenolide variant over another. Natural (archaeology) ; Biology Phytochemistry and Bioactive Compounds ; Traditional and Medicinal Uses of Annonaceae ; Phytochemical Studies and Bioactivities
Authors: Byung-Jin Kwon | Seonghun Pyo | Yub Je | Hee‐Seon Seo | Sang-Goo Lee | Yongrae Roh
Source: AIP Advances (article, 2024-04-01)
Field: Materials Science — Materials Chemistry

Precise evaluation of the material constants of [011]-poled mangan-doped 0.32Pb(In1/2Nb1/2)O3-0.39Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystals Recently, there has been a surge of interest in [011]-poled Mn: PIN-PMN-PT piezoelectric single crystals for high-power transducers. These crystals boast impressive electromechanical coupling coefficients, piezoelectric constants in the transverse mode, and excellent heat resistance due to their high mechanical quality factor. To effectively design transducers using these crystals, understanding their material constants is crucial. Our study focused on determining these constants by employing the resonance method. We created eleven different resonators, analyzed their impedance spectra, and derived seventeen elastic compliance, piezoelectric, and dielectric constants. The precision of the obtained material constants was enhanced by minimizing the difference between the impedance spectra found through finite element analyses and actual measurements of each resonator. The accuracy of these derived constants was validated by comparing the impedance spectra obtained from analysis with those measured experimentally. This novel approach demonstrated a capability to derive more precise material constants than prior studies. These refined material constants hold the potential to enable more precise and effective design of acoustic transducers constructed from the single crystals. Doping ; Materials science ; Condensed matter physics ; Analytical Chemistry (journal) ; Crystallography ; Optoelectronics ; Chemistry ; Physics Ferroelectric and Piezoelectric Materials ; Microwave Dielectric Ceramics Synthesis ; Acoustic Wave Resonator Technologies
Authors: Luca Steiner | Andreas J. Achazi | Anne‐Marie Kelterer | Beate Paulus | Hans‐Ulrich Reißig
Source: Chemistry - A European Journal (article, 2024-03-21)
Field: Chemistry — Organic Chemistry

Diastereoselective Dearomatizing Cyclizations of 5‐Arylpentan‐2‐ones by Samarium Diiodide – A Computational Analysis This study analyzes the samarium diiodide-promoted cyclizations of 5-arylpentan-2-ones to dearomatized bicyclic products utilizing density functional theory. The reaction involves a single electron transfer to the carbonyl group, which occurs synchronously with the rate determining cyclization event, and a second subsequent proton-coupled electron transfer. These redox reactions are accurately computed employing small core pseudo potentials explicitly involving all f-electrons of samarium. Comparison of the energies of the possible final products rules out thermodynamic control of the observed regio- and diastereoselectivities. Kinetic control via appropriate transition states is correctly predicted, but to obtain reasonable energy levels the influence of the co-solvent hexamethylphosphortriamide has to be estimated by using a correction term. The steric effect of the bulky samarium ligands is decisive for the observed stereoselectivity. Carbonyl groups in para-position of the aryl group change the regioselectivity of the cyclization and lead to spiro compounds. The computations suggest again kinetic control of this deviating outcome. However, the standard mechanism has to be modified and the involvement of a complex activated by two SmI<sub>2</sub> moieties is proposed in which two electrons are transferred simultaneously to form the new C-C bond. Computation of model intermediates show the feasibility of this alternative+ mechanism. Samarium diiodide ; Samarium ; Chemistry ; Organic chemistry Asymmetric Synthesis and Catalysis ; Chemical synthesis and alkaloids ; Asymmetric Hydrogenation and Catalysis
Authors: Dong‐Hoon Lee | Chul‐Woong Woo | Hwon Heo | Yousun Ko | Ji Sung Jang | Seongwon Na | Nari Kim | Dong‐Cheol Woo | Kyung Won Kim | Do-Wan Lee
Source: Biomedicines (article, 2024-02-07)
Field: Materials Science — Materials Chemistry

Mapping Changes in Glutamate with Glutamate-Weighted MRI in Forced Swim Test Model of Depression in Rats Chemical exchange saturation transfer with glutamate (GluCEST) imaging is a novel technique for the non-invasive detection and quantification of cerebral Glu levels in neuromolecular processes. Here we used GluCEST imaging and <sup>1</sup>H magnetic resonance spectroscopy (<sup>1</sup>H MRS) to assess in vivo changes in Glu signals within the hippocampus in a rat model of depression induced by a forced swim test. The forced swimming test (FST) group exhibited markedly reduced GluCEST-weighted levels and Glu concentrations when examined using <sup>1</sup>H MRS in the hippocampal region compared to the control group (GluCEST-weighted levels: 3.67 ± 0.81% vs. 5.02 ± 0.44%, <i>p</i> < 0.001; and Glu concentrations: 6.560 ± 0.292 μmol/g vs. 7.133 ± 0.397 μmol/g, <i>p</i> = 0.001). Our results indicate that GluCEST imaging is a distinctive approach to detecting and monitoring Glu levels in a rat model of depression. Furthermore, the application of GluCEST imaging may provide a deeper insight into the neurochemical involvement of glutamate in various psychiatric disorders. Behavioural despair test ; Glutamate receptor ; Neurochemical ; Hippocampal formation ; Hippocampus ; Magnetic resonance imaging ; Rat model ; In vivo ; Depression (economics) ; Neuroscience ; Chemistry ; Internal medicine ; Nuclear magnetic resonance ; Endocrinology ; Medicine ; Psychology ; Biology ; Radiology ; Physics Lanthanide and Transition Metal Complexes ; Advanced MRI Techniques and Applications ; Electron Spin Resonance Studies
Authors: Rubén Pellicer-Guridi | Koen Custers | Joseba Solozabal‐Aldalur | A. Brodolin | Jason Francis | J. J. M. Varga | Asier Mongelos | J. Casanova | Margarethus M. Paulides | Gabriel Molina‐Terriza
Source: Advanced Quantum Technologies (article, 2024-11-29)
Field: Materials Science — Materials Chemistry

Versatile Quadrature Antenna for Precise Control of Large Electron Spin Ensembles in Diamond Abstract An easily reproducible inexpensive microwave antenna that can generate a strong and homogeneous magnetic field of arbitrary polarization is presented, which enables fast and coherent control of electron spins over a large volume. Unlike preceding works, a resonant antenna with ample optical access and which maintains its resonant behavior regardless of the proximity of other experimental hardware components is presented. This robustness is crucial as it enables using microscope objectives with short working distances to perform wide‐field imaging/sensing with bulk diamonds. The antenna generates a magnetic field strength of 22.3 A for 1 W total driving power, which doubles the power efficiency compared with previously reported patch antenna designs. The magnetic field homogeneity in a volume of , and is within 3%, 8% and 14%, respectively. The antenna can be driven off‐resonance without affecting the ellipticity and inhomogeneity of the field, and has a full‐width‐at‐half‐maximum bandwidth of 200 MHz. Its resonant frequency can be tuned over a 400 MHz range via varactors. The PCB files are provided open‐source. This work facilitates a robust and versatile piece of instrumentation, being particularly appealing for applications such as high sensitivity magnetometry and wide‐field imaging/sensing with nitrogen‐vacancy centers. Diamond ; Electron ; Quadrature (astronomy) ; Spin (aerodynamics) ; Physics ; Condensed matter physics ; Materials science ; Quantum mechanics ; Optics Diamond and Carbon-based Materials Research ; Graphene research and applications ; High-pressure geophysics and materials
Authors: Mateo Uldemolins | Andrej Mesaroš | G. D. Gu | Alexandra Palacio‐Morales | M. Aprili | Pascal Simon | Freek Massee
Source: Nature Communications (article, 2024-10-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Hund’s coupling mediated multi-channel quantum phase transition of a single magnetic impurity in Fe(Se, Te) Understanding the interplay between individual magnetic impurities and superconductivity is crucial for bottom-up construction of novel phases of matter. Sub-gap bound states that are used in this endeavor are typically considered as independent entities that each result from the exchange scattering between the respective impurity orbitals and electrons of the superconducting condensate. Here we present experimental evidence of individual multi-spin impurities where the sub-gap states are not independent. Specifically, we find that by tuning the energy of the state closest to zero through zero, all other sub-gap states change particle-hole asymmetry as well. We show that this can be understood by including Hund's coupling, which favors high-spin configurations, into a multi-orbital Anderson model. Unlike for the case of independent spins, the transition we observe signals the simultaneous departure of more than one quasiparticle from the impurity, while the parity of the ground state may remain unchanged. Our results show that Hund's coupling is not only crucial in generating high-spin impurities, but also to understand the transition between two distinct ground states, and should therefore be taken into account for e.g. impurity-based band-structure engineering. Condensed matter physics ; Physics ; Magnetic impurity ; Spins ; Quasiparticle ; Impurity ; Anderson impurity model ; Quantum phase transition ; Superconductivity ; Ground state ; Spin (aerodynamics) ; Asymmetry ; Electron ; Phase transition ; Quantum mechanics Iron-based superconductors research ; Rare-earth and actinide compounds ; Physics of Superconductivity and Magnetism
Authors: Jun‐Xiao Lin | Bo-Jun Chen | Shih-Min Hung | Wei‐Hsiang Liao | M. Hehn | Shih‐Jye Sun | Yu‐Ying Chang | Thomas Hauet | J. Hohlfeld | S. Mangin | Hua‐Shu Hsu
Source: ACS Applied Electronic Materials (article, 2024-12-16)
Field: Materials Science — Materials Chemistry

Electrically Modulated Multilevel Optical Chirality in GdFeCo Thin Films This study introduces a simple approach to dynamically control multilevel optical ellipticity in ferrimagnetic GdFeCo alloys by switching the spin orientation through Joule heating induced by electrical current, with the assistance of a low magnetic field of 3.5 mT. It is demonstrated that selecting specific compositions of Gd <sub><i>x</i></sub> (FeCo)<sub>100-<i>x</i></sub> alloys, with magnetic compensation temperatures near or above room temperature, allows for significant manipulation of the circular dichroism (CD) effect. This control enables the transformation of transmitted light from linearly polarized to elliptically polarized or the reversal of the rotation direction of elliptically polarized light across the photon energy range from visible (vis) to ultraviolet (UV). The efficacy of this method is rooted in the dominant contributions of FeCo to the CD effect in the vis-to-UV energy range. Because the magnetization of FeCo remains relatively independent of the temperature, substantial optical ellipticity is maintained for optical device applications, regardless of whether the compensation temperature is approached or crossed. Our results highlight the potential of GdFeCo thin films in chiral optics and demonstrate the selective contributions of rare-earth transition-metal elements to the CD effects, facilitating the design of advanced optical devices leveraging energy-resolved CD phenomena. Chirality (physics) ; Materials science ; Thin film ; Nanotechnology ; Chemistry ; Condensed matter physics ; Physics ; Quantum mechanics Phase-change materials and chalcogenides ; Chalcogenide Semiconductor Thin Films ; Magnetic and transport properties of perovskites and related materials
Authors: Francisco J. Quero | Guy Aidelberg | Hortense Vielfaure | Yann Huon de Kermadec | Séverine Cazaux | Amir Pandi | Ana Pascual-Garrigos | Aníbal Arce | Samuel Asamoah Sakyi | Urs Gaudenz | Fernán Federici | Jenny Molloy | Ariel B. Lindner
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2024-11-03)
Field: Chemistry — Physical and Theoretical Chemistry

qByte: Open-source isothermal fluorimeter for democratizing analysis of nucleic acids, proteins and cells Abstract Access to affordable and reliable scientific instrumentation remains a significant barrier to the democratization of healthcare and scientific research. In the field of biotechnology, in particular, the complexity, cost, and infrastructure requirements of many instruments continue to limit their accessibility, especially in resource-limited environments. Despite the recent increase in the development of open-source tools, driven by advances in digital fabrication and electronic prototyping, few of these projects have reached large-scale implementation or validation in real-world settings. Here, we present qByte, an open-source, 8-tube isothermal fluorimeter designed to overcome these barriers by offering a cost-effective ($60) yet production-ready solution. qByte leverages standard digital manufacturing and Printed Circuit Board (PCB) assembly techniques and is designed to be portable, making it ideal for both laboratory and field use. The device has been benchmarked against commercial real-time thermocyclers and spectrophotometers, showing comparable results across four key applications: nucleic acid amplification and detection, analysis of protein activity and stability, genetic construct characterization, and bacterial viability tests. Further testing including the on-site diagnosis of human parasites in Kumasi, Ghana, and field work in Patagonia, Chile, validated qByte’s reliability in real-world conditions. Taken together, our results proved qByte as flexible and reliable equipment for a variety of biological tests and applications, while its affordability and open-source design simplify further development and allow adaptation to the needs of future users. Fluorometer ; Nucleic acid ; Open source ; Isothermal process ; Chemistry ; Biochemistry ; Computer science ; Thermodynamics ; Physics ; Programming language ; Fluorescence thermodynamics and calorimetric analyses ; Computational Drug Discovery Methods ; Metabolomics and Mass Spectrometry Studies