jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: A. Okamoto | Shintaro Toda | Takumi Tsujihata | Takaki Kamada | Maowei Huang | Yusuke Hashimoto | Seiichi Isojima | Hirotake Kajii | Satoshi Seino | Tetsusei KURASHIKI
Source: Advanced Materials Interfaces (article, 2024-10-31)
Field: Materials Science — Materials Chemistry

Enhanced Optical Properties of Green‐Emitting InP Quantum Dots with Matched Junctions of the Core and Mn‐Doped Novel Shells Abstract Indium phosphide (InP) quantum dots (QDs) offer a promising alternative to (Restriction of Hazardous Substances) restricted cadmium‐based QDs, however, their performance is limited by surface defects and weak quantum confinement. This study introduces a novel approach to enhance the optical properties of InP QDs through manganese (Mn) doping into the zinc selenide and zinc sulfide shell. This aims to expand the bandgap of the shells and adjust its lattice constant to better match the InP core. A comprehensive investigation of the effect of Mn‐doping concentration reveals that optimal properties are developed at a 10% feed ratio, resulting in improved crystallinity, reduced interfacial defects, and enhanced quantum confinement. X‐ray diffraction and transmission electron microscopy confirm the structural improvements and spectroscopic analyses demonstrate remarkable enhancement of optical properties. Notably, the photoluminescence quantum yield reaches 83% in the green emission region (λ ≈535 nm), a significant improvement over undoped QDs. Time‐resolved photoluminescence measurements indicate extended carrier lifetimes, supporting the effect of defect reduction. This strategy not only addresses the long‐standing challenges of InP QDs but also opens new avenues for designing high‐performance, environmentally friendly nanomaterials for various optoelectronic applications, including displays, lighting, and photovoltaics. Materials science ; Quantum dot ; Core (optical fiber) ; Doping ; Optoelectronics ; Nanotechnology ; Composite material Quantum Dots Synthesis And Properties ; Semiconductor Quantum Structures and Devices ; Chalcogenide Semiconductor Thin Films
Authors: A. Amoddeo
Source: Symmetry (review, 2024-12-27)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Moving Mesh Partial Differential Equation Modelling of a 5CB Nematic Liquid Crystal Confined in Symmetric and Asymmetric Pi-Cells: A Review The switching properties of nematic liquid crystals under electrical and mechanical stresses play a fundamental role in the design and fabrication of electro-optical devices. Depending on the stress applied to a nematic texture confined in a pi-cell, different nematic configurations are allowed inside the cell, while the induced distortion is relaxed by means of growing biaxial domains which can end with the order reconstruction phenomenon, a transition connecting two topologically different nematic textures which can occur in different regions of the pi-cell. Due to the different space and time scales involved, modelling in the frame of the Landau–de Gennes order tensor theory is mandatory to correctly describe the fast-switching mechanisms involved, while from a computational point of view, sophisticated numerical techniques are required to grasp tiny and fast features which can be predicted by the mathematical modelling. In this paper, we review the results obtained from the mathematical and numerical modelling of a 5CB liquid crystal confined in a pi-cell performed by using a numerical technique based on the equidistribution principle, tailored for the description of a complex physical system in which fast switching phenomena are coupled with strong distortions. After a recap on the underneath theory and on the numerical method, we focus on the switching properties of the nematic material when subjected to variable mechanical and electrical stresses in both symmetric and asymmetric conditions. Liquid crystal ; Biaxial nematic ; Cauchy stress tensor ; Tensor (intrinsic definition) ; Distortion (music) ; Texture (cosmology) ; Materials science ; Numerical analysis ; Optics ; Mechanics ; Physics ; Classical mechanics ; Mathematics ; Mathematical analysis ; Geometry ; Computer science ; Image (mathematics) ; Optoelectronics Liquid Crystal Research Advancements ; Plant Reproductive Biology ; Nonlinear Dynamics and Pattern Formation
Authors: Hemant Kumar Tatapudi | Ravinder Bairam | Vanaja Kassireddy | Riazuddin Mohammed | Ankitha Baithi | Sowmya Yata
Source: Drug Analytical Research (article, 2024-07-19)
Field: Chemistry — Analytical Chemistry

An Optimized Box-Behnken Design RP-HPLC Method For The Quantification Of Umiclinidinium Bromide And Vilanterol Trifenate In Oral Inhalation A liquid chromatographic method with enhanced efficacy has been proposed for the simultaneous quantification of Vilanterol Trifenate and Umiclinidinium Bromide in pharmaceutical formulation. This method is straightforward, sensitive, accurate, precise, and dependable. The RP-HPLC method's experimental parameters were multivariately optimized using the design of experiments (DoE). Mathematical models were created using three independent variables: the percentage of acetonitrile, the strength of the buffer, and the pH of the mobile phase. In order to examine the response surface methodology and the effects of these independent factors, a box-behnken design (BBD) was utilized. The optimized and forecasted data from the contour diagram utilized a mixture of acetonitrile (58.6% v/v) and phosphate buffer (12.6 mM) with a pH of 5.1. The flow rate was adjusted to 1 milliliter per minute and the analytical wavelength employed was 272 nm. The pharmaceuticals were successfully separated with high resolution in less than 6 minutes under ideal conditions, and the validation process was conducted in accordance with the requirements set by the International Council for Harmonisation (ICH). The findings indicated that the Quality by Design technique was effective in optimizing the RP-HPLC method for quantifying Vilanterol Trifenate and Umiclinidinium Bromide. Box–Behnken design ; Inhalation ; Bromide ; Chromatography ; Chemistry ; Pharmacology ; Medicine ; Response surface methodology ; Anesthesia ; Organic chemistry Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Sensors ; Analytical Chemistry and Chromatography
Authors: Eli C. Zuercher | Andrew T. Poore | Devendra Prajapat | Joseph Palazzo | Astrid Thomas | Caitlin Birthright | Jack Lawrence | Ming Chen | Shiliang Tian
Source: Dalton Transactions (article, 2024-12-05)
Field: Chemistry — Spectroscopy

Secondary sphere interactions modulate peroxynitrite scavenging by the E2 domain of amyloid precursor protein Peroxynitrite (ONOO<sup>-</sup>) is a highly reactive nitrogen species that can cause significant damage to proteins, lipids, and DNA. Various enzymes, including metalloenzymes, play crucial roles in reducing ONOO<sup>-</sup> concentrations to protect cellular components. While the interaction of ONOO<sup>-</sup> with heme proteins is well known, the reduction by Cu-containing proteins is less studied. Amyloid precursor protein (APP), implicated in Alzheimer's disease, has an E2 domain that binds copper ions with a dissociation constant of <i>K</i><sub>D</sub> ∼ 10<sup>-12</sup> M and is proposed to be involved in iron homeostasis, copper trafficking, and oxidative stress response. Our recent studies using EXAFS, UV-Vis, and EPR spectroscopy revealed a previously unidentified labile water ligand in the Cu(II) site of the E2 domain, suggesting reactivity with anionic substrates like ONOO<sup>-</sup>. Experimental data showed that Cu(I)-E2 reduces ONOO<sup>-</sup> at a significant rate (1.1 × 10<sup>5</sup> M<sup>-1</sup> s<sup>-1</sup>), comparable to native peroxynitrite scavengers, while maintaining active site integrity through multiple redox cycles. This study further investigates the mechanism of ONOO<sup>-</sup> reduction by Cu(I)-E2 using the Griess assay, demonstrating that reduction occurs <i>via</i> single electron transfer, forming nitrite and nitrate. This process aligns with previous findings that Cu(I)-E2 is oxidized to Cu(II)-E2 upon ONOO<sup>-</sup> reduction. Mutations at Lys435, affecting secondary sphere interactions, revealed that factors beyond electrostatics are involved in substrate recruitment. MD simulations suggest that steric hindrance from a newly formed hydrogen bond also plays a role. Understanding ONOO<sup>-</sup> reduction by the E2 domain of APP expands our knowledge of copper proteins in mitigating oxidative stress and elucidates their physiological and pathological roles, particularly in Alzheimer's disease. Peroxynitrite ; Scavenging ; Chemistry ; Amyloid (mycology) ; Domain (mathematical analysis) ; Protein aggregation ; Biophysics ; Biochemistry ; Biology ; Antioxidant ; Superoxide ; Enzyme ; Inorganic chemistry Molecular Sensors and Ion Detection ; Redox biology and oxidative stress ; Mitochondrial Function and Pathology
Authors: Daria Gashnikova | Florian Maurer | Eric Sauter | Sarah Bernart | Jelena Jelic | Paolo Dolcet | Carina B. Maliakkal | Yuemin Wang | Christof Wöll | Felix Studt | Christian Kübel | Maria Casapu | Jan‐Dierk Grunwaldt
Source: Angewandte Chemie (article, 2024-06-15)
Field: Materials Science — Materials Chemistry

Highly Active Oxidation Catalysts through Confining Pd Clusters on CeO<sub>2</sub> Nano‐Islands Abstract CeO 2 ‐supported noble metal clusters are attractive catalytic materials for several applications. However, their atomic dispersion under oxidizing reaction conditions often leads to catalyst deactivation. In this study, the noble metal cluster formation threshold is rationally adjusted by using a mixed CeO 2 ‐Al 2 O 3 support. The preferential location of Pd on CeO 2 islands leads to a high local surface noble metal concentration and promotes the in situ formation of small Pd clusters at a rather low noble metal loading (0.5 wt %), which are shown to be the active species for CO conversion at low temperatures. As elucidated by complementary in situ/operando techniques, the spatial separation of CeO 2 islands on Al 2 O 3 confines the mobility of Pd, preventing the full redispersion or the formation of larger noble metal particles and maintaining a high CO oxidation activity at low temperatures. In a broader perspective, this approach to more efficiently use the noble metal can be transferred to further systems and reactions in heterogeneous catalysis. Noble metal ; Catalysis ; Oxidizing agent ; Metal ; Heterogeneous catalysis ; Chemical engineering ; Cluster (spacecraft) ; Chemistry ; Nanoparticle ; Precious metal ; Nanotechnology ; Materials science ; Inorganic chemistry ; Organic chemistry Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions ; Nanomaterials for catalytic reactions
Authors: María Rosell | Verónica Torregrosa‐Rivero | Diego Herrera‐Ochoa | Andrés Garzón‐Ruiz | Javier García‐Martínez | Elena Serrano | Cristina Martín
Source: ChemPhotoChem (article, 2024-05-24)
Field: Materials Science — Materials Chemistry

Unlocking the Potential of Different Types of Biomass‐Derived Carbon Dots as Fluorescence Lifetime Imaging Probes Abstract The ongoing search for innovative and environmentally friendly luminescent materials coupled with customizable physical and chemical properties at the nanoscale positions carbon dots (CDots) as ideal candidates for photonic applications. However, even today, their rational design for specific applications remains elusive due to the unknown relationship between optical and structural properties. Therefore, this study aims to fill this gap by linking the chemical structure of the precursor and synthetic conditions to the final structural composition of the CDots and, by extension, to their optical properties. The study shows that while CDots are chemically stable, their optical properties, which are determined by the carbonaceous core and surface groups, are highly pH dependent. These properties, together with the long fluorescence lifetimes observed in living cells (&gt;10 ns), make these biomass‐derived CDots promising probes for time‐resolved fluorescence imaging. Nanotechnology ; Fluorescence ; Fluorescence-lifetime imaging microscopy ; Materials science ; Optics ; Physics Carbon and Quantum Dots Applications ; Nanocluster Synthesis and Applications ; Quantum Dots Synthesis And Properties
Authors: Dongxin Zhang | Aravind Raji | Luis M. Vicente‐Arche | Alexandre Gloter | Manuel Bibès | Lucía Iglesias
Source: arXiv (Cornell University) (preprint, 2024-11-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Achieving superconductivity in infinite-layer nickelate thin films by aluminum sputtering deposition The recent discovery of superconductivity in infinite-layer (IL, ABO$_2$) nickelates has opened a new avenue to deepen the understanding of high-temperature superconductivity. However, progress in this field is slowed by significant challenges in material synthesis and the scarcity of research groups capable of producing high quality superconducting samples. IL nickelates are obtained from a reduction of the perovskite ABO$_3$ phase, typically achieved by annealing using CaH$_2$ as a reducing agent. Here, we present a new method to synthesize superconducting infinite-layer nickelate Pr$_{0.8}$Sr$_{0.2}$NiO$_2$ thin films using an aluminum overlayer deposited by sputtering as a reducing agent. We systematically optimized the aluminum deposition parameters and obtained superconducting samples reduced either in situ or ex situ (after air exposure of the precursor ABO$_3$ films). A comparison of their crystalline quality and transport properties shows that in situ Al reduction enhances the quality of the superconducting Pr$_{0.8}$Sr$_{0.2}$NiO$_2$ thin films, achieving a maximum superconducting transition temperature $T_{c}^{onset}$ of 17 K, in agreement with the optimum value reported for this compound. This simple synthesis route, much more accessible than existing methods, offers better control and reproducibility over the topotactic transformation, opening new opportunities to gain insights into the physics of superconductivity in nickelates. Sputtering ; Superconductivity ; Layer (electronics) ; Deposition (geology) ; Thin film ; Materials science ; Aluminium ; Layer by layer ; Metallurgy ; Condensed matter physics ; Nanotechnology ; Physics ; Geology Copper Interconnects and Reliability ; Physics of Superconductivity and Magnetism ; nanoparticles nucleation surface interactions
Authors: Rakan Saeb | Bryan Boulenger | Josep Cornellà
Source: ChemRxiv (preprint, 2024-04-03)
Field: Chemistry — Organic Chemistry

“Naked Nickel”-Catalyzed Amination of Heteroaryl Bromides In this article we report that the air-stable “naked nickel” [Ni(4-tBustb)3] is a competent catalyst in thermal C–N bond formation between (hetero)aryl bromides and N-based nucleophiles. The catalytic system is characterized by a “naked nickel” complex and Zn, the absence of external light sources, photocatalysts, exogeneous ligands, as well as electrical setups. By applying this method, various heteroaryls bearing Lewis-basic heteroatoms can be accommodated and directly aminated with a set of primary and secondary amines. Amination ; Nickel ; Catalysis ; Chemistry ; Combinatorial chemistry ; Business ; Organic chemistry Catalytic Cross-Coupling Reactions ; Asymmetric Hydrogenation and Catalysis ; Nanomaterials for catalytic reactions
Authors: G. L. Huang | K. C. Ting | Nagaraju Narayanam | Dong-Rong Wu | Tzung-En Hsieh | K.L. Tsai | Dawei Yang | Qi-Xun Tang | Bo-Kai Su | Yuting Kang | Shing‐Jong Huang | Ching‐Hsiang Chen | Yuan‐Pin Chang | Lan‐Sheng Yang | Yu‐Chiang Chao | Elise Y. Li | Yi‐Hsin Liu
Source: Angewandte Chemie International Edition (article, 2024-12-06)
Field: Materials Science — Materials Chemistry

Unexpected Magnetic Moments in Manganese‐Doped (CdSe)<sub>13</sub> Nanoclusters: Role of Ligands This study explores the enhancement in magnetic and photoluminescence properties of Mn<sup>2+</sup>-doped (CdSe)<sub>13</sub> nanoclusters, significantly influenced by the introduction of paramagnetic centers through doping, facilitated by optimized precursor chemistry and precisely controlled surface ligand interactions. Using a cost-effective and scalable synthesis approach with elemental Se and NaBH<sub>4</sub> (Se-NaBH<sub>4</sub>) in n-octylamine, we tailored bonding configurations (Cd-O, Cd-N, and Cd-Se) on the surface of nanoclusters, as confirmed by EXAFS analysis. These bonding configurations allowed for tunable Mn<sup>2+</sup>-doping with tetrahedral coordination, further stabilized by hydrogen-bonded acetate ligands, as evidenced by <sup>13</sup>C NMR and IR spectroscopy. Mulliken charge analysis indicates that the charge redistribution on Se<sup>2-</sup> suggests electron transfer between surface ligands and the nanocluster, contributing to spin fluctuations. These tailored configurations markedly increased the nanoclusters' magnetic susceptibility and photoluminescence efficiency. The resulting nanoclusters demonstrated a clear concentration-dependent response in emission lifetimes and intensities upon exposure to magnetic field effects (MFE) and spin-spin coupling, alongside a large magnetic moment exceeding 40 μ<sub>B</sub> at 180 K. These findings highlight the potential of these nanoclusters for magneto-optical devices and spintronic applications, showcasing their tunable magnetic properties and exciton dynamics. Nanoclusters ; Photoluminescence ; Magnetic moment ; Spintronics ; Materials science ; Paramagnetism ; Doping ; Magnetic semiconductor ; Dopant ; Chemical physics ; Crystallography ; Chemistry ; Nanotechnology ; Condensed matter physics ; Ferromagnetism ; Optoelectronics ; Physics Quantum Dots Synthesis And Properties ; Nanocluster Synthesis and Applications ; Chalcogenide Semiconductor Thin Films
Authors: Berenika Masaryk | Miroslav Soural
Source: ACS Omega (article, 2024-09-05)
Field: Chemistry — Organic Chemistry

Metal-Free Synthesis of Polysubstituted Triazoloquinoxalines Using Alkynols as the Key Building Blocks <i>o</i>-Phenylenediamines, <i>o</i>-nitroanilines, and Boc-<i>o</i>-phenylenediamines were converted to <i>N</i>-Ts/Ns-<i>o</i>-phenylenediamines, followed by Mitsunobu alkylation with prop-2-yn-1-ols. After one-pot azidation, the resulting intermediates underwent Huisgen cycloaddition, which yielded Ts/Ns-dihydrotriazoloquinoxalines. Cleavage of the arylsulfonyl moiety provided (dihydro)triazoloquinoxalines with the possibility of modifying the <i>N</i> <sup>5</sup> position. The application of but-3-yn-1-ols and pent-4-yn-1-ols allowed the preparation of benzotriazolodiazepines and benzotriazolodiazocines. The developed protocols enable the preparation of diversely substituted products from readily available starting materials under mild and metal-free conditions. Key (lock) ; Computer science ; Combinatorial chemistry ; Chemistry ; Computer security Synthesis and Biological Evaluation ; Click Chemistry and Applications ; Cyclopropane Reaction Mechanisms
Authors: J. Cernicharo | C. Cabezas | M. Agúndez | Yasuki Endo | B. Tercero | N. Marcelino | P. de Vicente
Source: arXiv (Cornell University) (preprint, 2024-06-10)
Field: Chemistry — Physical and Theoretical Chemistry

QUIJOTE discovery of the cation radicals HC5N+ and HC7N+ We present the discovery with the QUIJOTE line survey of the cations HC5N+ and HC7N+ in the direction of TMC-1. Seven lines with half-integer quantum numbers from J=25/2-23/2 to 37/2-35/2 have been assigned to HC5N+ and eight lines from J=55/2-53/2 to 71/2-69/2 to HC7N+. Both species have inverted 2Pi ground electronic states with very good estimates for their B0 and AS0 constants based on optical observations. The lines with the lowest J of HC5N+ exhibit multiple components due to the hyperfine structure introduced by the H and N nuclei. However, these different components collapse for the higher J. No hyperfine structure is found for any of the lines of HC7N+. The derived effective rotational and distortion constants for HC5N+ are Beff = 1336.662+/- 0.001 MHz and Deff = 27.4+/-2.6 Hz, while for HC7N+ they are Beff = 567.85036+/-0.00037 MHz and Deff = 4.01+/-0.19 Hz. From the observed intensities, we derived Trot = 5.5+/-0.5K and N = (9.9+/-1.0)x 1010 cm-2 for HC5N+, while we obtained Trot = 8.5+/-0.5K and N = (2.3+/-0.2)x1010 cm-2 for HC7N+. The HC5N/HC5N+, C5N/HC5N+, C5N-/HC5N+, HC7N/HC7N+, HC5N+/HC7N+, and C7N-/HC7N+ abundance ratios are 670+/-80, 4.8+/-0.8, 1.2+/-0.2, 1000+/-150, 4.2+/-0.5, and 2.2+/-0.2, respectively. We have run chemical modelling calculations to investigate the formation and destruction of these new cations. We find that these species are mainly formed through the reactions of H2 and the cations C5N+ and C7N+, and by the reactions of H+ with HC5N and HC7N, while they are mostly destroyed through a reaction with H2 and a dissociative recombination with electrons. Based on the underestimation of the abundances of HC5N+ and HC7N+ by the chemical model by a factor around 20, we suggest that the rate coefficients currently assumed for the reactions of these cations with H2 could be too high by the same factor, something that will be worth investigating. Radical ; Chemistry ; Organic chemistry Various Chemistry Research Topics ; Chemistry and Stereochemistry Studies ; Free Radicals and Antioxidants
Authors: H. R. Christiansen | Rodrigo Maciel Lima
Source: Physica B Condensed Matter (article, 2024-09-26)
Field: Materials Science — Materials Chemistry

Effective particles in a multishell nanostructure with hardcore Nanostructure ; Materials science ; Nanotechnology Quantum Dots Synthesis And Properties ; Gold and Silver Nanoparticles Synthesis and Applications ; nanoparticles nucleation surface interactions
Authors: Masaru Miyagi | Evan Kiesel | Kelao Neumbo | Takashi Nakazawa
Source: ChemRxiv (preprint, 2024-02-06)
Field: Chemistry — Spectroscopy

Deuterium Labeling of Isoaspartic and Isoglutamic Acids for Mass Spectrometry Analysis Isoaspartic acid (isoAsp) is a common protein modification that spontaneously arises from asparagine or aspartic acid, and it has been linked to various diseases and health conditions. However, current methods for identifying isoAsp sites in proteins often suffer from ambiguity and have not gained widespread adoption. We have developed a novel method that exclusively labels isoAsp with deuterium. This method capitalizes on the unique structural characteristics of isoAsp residues, which possess a free α-carboxyl group and can form an oxazolone ring. Once the oxazolone ring forms, it facilitates racemization at the Cα-position, incorporating a deuteron from a D2O solvent. The sites of deuterium-incorporated isoAsp in proteins can be unequivocally determined by comparing the precursor and product ion masses of the peptides from proteins reacted in H2O and D2O. The effectiveness of this method has been demonstrated through its application to model proteins, lysozyme and rituximab. Furthermore, we have confirmed that the isoAsp deuterium labeling reaction efficiently labels both L- and D-isoAsp without distinction, as well as isoglutamic acid (isoGlu), for which no effective detection methods currently exist. Mass spectrometry ; Deuterium ; Chemistry ; Chromatography ; Nuclear physics ; Physics Mass Spectrometry Techniques and Applications ; Analytical Chemistry and Chromatography ; Metabolomics and Mass Spectrometry Studies