jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Tejal Pawale | Justin Swain | Mohammad Reza Hashemi | Giordano Tierra | Xiao Li
Source: Advanced Materials Interfaces (article, 2023-04-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Dynamic Motions of Topological Defects in Nematic Liquid Crystals under Spatial Confinement Abstract Topological defects (TDs) have become a sensational topic due to their significant influence on the unusual optical and physiochemical characteristics of the material. To facilitate their application across a wide range of disciplines it is desirable to analyze and gain fundamental understanding of TDs in both equilibrium and nonequilibrium systems. Liquid crystals (LCs) are considered an ideal system for study given the direct visualization of TDs and a straightforward analyzation process. In addition to the equilibrium morphology of LC TDs, it is also of great interest to track and control the formation and annihilation of defects during thermodynamic processes. However, controlling the dynamic behavior of formed defects remains a challenge. Here, nematic LCs confined in a cell exhibiting surfaces with periodic anchoring conditions containing surface topography are relied on. The effects of patterned surface characteristics such as width, periodicity, and degree of curvature on defects dynamic motion, stabilization, and annihilation are explored. The computational experiments recapitulate the TDs transition path and provide free energy‐based predictions of critical distances for defect annihilation. Taken together, this simple approach offers a promising opportunity to control the dynamics of TDs in LCs through chemical patterned surfaces with topography. Annihilation ; Liquid crystal ; Non-equilibrium thermodynamics ; Materials science ; Curvature ; Chemical physics ; Topological defect ; Surface (topology) ; Thermodynamic equilibrium ; Topology (electrical circuits) ; Nanotechnology ; Condensed matter physics ; Optoelectronics ; Physics ; Thermodynamics ; Geometry Liquid Crystal Research Advancements ; Micro and Nano Robotics ; Advanced Materials and Mechanics
Authors: László Petri | Péter Ábrányi‐Balogh | Noémi Csorba | Aaron Keeley | József Simon | Ivan Ranđelović | József Tóvári | Gitta Schlosser | Dániel Szabó | László Drahos | György M. Keserű
Source: Molecules (article, 2023-03-29)
Field: Chemistry — Organic Chemistry

Activation-Free Sulfonyl Fluoride Probes for Fragment Screening SuFEx chemistry is based on the unique reactivity of the sulfonyl fluoride group with a range of nucleophiles. Accordingly, sulfonyl fluorides label multiple nucleophilic amino acid residues, making these reagents popular in both chemical biology and medicinal chemistry applications. The reactivity of sulfonyl fluorides nominates this warhead chemotype as a candidate for an external, activation-free general labelling tag. Here, we report the synthesis and characterization of a small sulfonyl fluoride library that yielded the 3-carboxybenzenesulfonyl fluoride warhead for tagging tractable targets at nucleophilic residues. Based on these results, we propose that coupling diverse fragments to this warhead would result in a library of sulfonyl fluoride bits (SuFBits), available for screening against protein targets. SuFBits will label the target if it binds to the core fragment, which facilitates the identification of weak fragments by mass spectrometry. Sulfonyl ; Nucleophile ; Reactivity (psychology) ; Chemistry ; Fluoride ; Combinatorial chemistry ; Warhead ; Reagent ; Stereochemistry ; Organic chemistry ; Inorganic chemistry ; Catalysis ; Medicine Click Chemistry and Applications ; Peptidase Inhibition and Analysis ; Chemical Synthesis and Analysis
Authors: Marta Solas | Miguel Ángel Muñoz | Fernando Martínez | Lorena Renedo | Samuel Suárez‐Pantiga | Roberto Sanz
Source: ChemPlusChem (article, 2023-09-29)
Field: Chemistry — Organic Chemistry

Catalyst‐ and Substrate‐Controlled Regiodivergent Synthesis of Carbazoles through Gold‐Catalyzed Cyclizations of Indole‐Functionalized Alkynols A wide variety of regioselectively substituted carbazole derivatives can be synthesized by the gold-catalyzed cyclization of alkynols bearing an indol-3-yl and an additional group at the homopropargylic positions. The regioselectivity of the process can be controlled by both the oxidation state of the gold catalyst and the electronic nature of the substituents of the alkynol moiety. The 1,2-alkyl migration in the spiroindoleninium intermediate, generated after indole attack to the activated alkyne, is favored with gold(I) complexes and for electron-rich aromatic substituents at the homopropargylic position, whereas the 1,2-alkenyl shift is preferred when using gold(III) salts and for alkyl or non-electron-rich aromatic groups. Carbazole ; Moiety ; Regioselectivity ; Catalysis ; Alkyne ; Indole test ; Chemistry ; Alkyl ; Substrate (aquarium) ; Combinatorial chemistry ; Cycloisomerization ; Organic chemistry Catalytic Alkyne Reactions ; Catalytic C–H Functionalization Methods ; Sulfur-Based Synthesis Techniques
Authors: Liang Yu | Ziwei Li | Hua Chen | Kaimin Chen | Xuhong Guo
Source: Polymers (article, 2023-04-19)
Field: Materials Science — Surfaces, Coatings and Films

Temperature Responsive Diblock Polymer Brushes as Nanoreactors for Silver Nanoparticles Catalysis Metal nanoparticles are widely used in catalysis. Loading metal nanoparticles into polymer brushes has aroused wide attention, but regulation of catalytic performance still needs to be improved. The novel diblock polymer brushes, polystyrene@sodium polystyrene sulfonate-b-poly (N-isopropylacrylamide) (PSV@PSS-b-PNIPA) and PSV@PNIPA-b-PSS with reversed block sequence, were prepared by surface initiated photoiniferter-mediated polymerization (SI-PIMP) and used as nanoreactors to load silver nanoparticles (AgNPs). The block sequence caused the difference of conformation and further affected the catalytic performance. PSV@PNIPA-b-PSS@Ag was found to be able to control the amount of AgNPs exposed to external reactant of 4-nitrophenol at different temperatures to achieve regulation of the reaction rate due to the hydrogen bonds and further physical crosslinking between PNIPA and PSS. Nanoreactor ; Polystyrene ; Materials science ; Poly(N-isopropylacrylamide) ; Polymer ; Catalysis ; Silver nanoparticle ; Nanoparticle ; Chemical engineering ; Polymerization ; Polystyrene sulfonate ; Polymer chemistry ; Copolymer ; Nanotechnology ; Chemistry ; Organic chemistry ; Composite material Polymer Surface Interaction Studies ; Nanocluster Synthesis and Applications ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Jorge R. Galeano-Cabral | Eliana Karr | Benny Schundelmier | Olatunde Oladehin | Eun Sang Choi | Theo Siegrist | Juan C. Ordóñez | Sarvjit Shastri | Valeri Petkov | Ryan Baumbach | Kaya Wei
Source: Physical Review Materials (article, 2023-02-28)
Field: Materials Science — Materials Chemistry

Enhanced thermoelectric properties of heavy-fermion compounds <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Yb</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>Ce</mml:mi><mml:mi>y</mml:mi></mml:msub><mml:msub><mml:mi>Sm</mml:mi><mml:mi>z</mml:mi></mml:msub><mml:msub><mml:mi>Ir</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Zn</mml:mi><mml:mn>20</mml:mn></mml:msub></mml:mrow></mml:math> (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>x</mml:mi><mml:mo>+</mml:mo><mml:mi>y</mml:mi><mml:mo>+</mml:mo><mml:mi>z</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:math>) Thermoelectric materials hold tremendous promise for advances in fundamental science and practical applications, particularly for robust electricity generation in extreme and remote environments. Despite this, for most materials the energy conversion efficiency is limited by the proportionality between the electrical and thermal conductivities and small values of the Seebeck coefficient for metals. It was previously reported that the heavy-fermion compound ${\mathrm{YbIr}}_{2}{\mathrm{Zn}}_{20}$ exhibits large Seebeck coefficient [E. Mun et al., Phys. Rev. B 86, 115110 (2012)] and thermoelectric figure of merit $ZT$ at 35 K [K. Wei et al., Sci. Adv. 5, eaaw6183 (2019)]. This behavior is primarily associated with strong hybridization between the $f$- and conduction electron states. Here, we seek to improve the thermoelectric properties through chemical substitution on the Yb site using Ce and Sm. By surveying different levels of substitution, we find that the thermoelectric properties vary strongly with the $f$-element ratio. This confirms that electronic hybridization dominates the thermoelectric properties and clarifies directions for optimizing these materials for applications. We also investigate the impact of the disorder on the thermal conductivity, where we find only weak variation with lanthanide content. Thermoelectric effect ; Seebeck coefficient ; Thermoelectric materials ; Thermal conductivity ; Materials science ; Figure of merit ; Lanthanide ; Condensed matter physics ; Electrical resistivity and conductivity ; Thermodynamics ; Physics ; Optoelectronics ; Quantum mechanics ; Ion Advanced Thermoelectric Materials and Devices ; Rare-earth and actinide compounds ; Magnetic and transport properties of perovskites and related materials
Authors: Lingfeng Wang | Lu Chen | Shihuan Chen | Qinglan Ye | Xuetang Xu | Fan Wang
Source: Chemistry - A European Journal (article, 2023-02-14)
Field: Materials Science — Electronic, Optical and Magnetic Materials

CoNi<sub>2</sub>S<sub>4</sub> Electrode with High Mass‐Loading for High‐Energy‐Density Supercapacitor: Role of S‐Containing Anions Exchange Anion exchange is recognized as an effective method to regulate the composition, electronic conductivity, and electrochemical behavior of the transition metal-based compounds. In this work, anion exchange is adopted as a rational post-treatment route to facilitate the capacitive activity of CoNi<sub>2</sub> S<sub>4</sub> nanoparticle arrays grown on carbon cloth (CC) with high mass-loading. As soaked in saturated Na<sub>2</sub> S solution, the CoNi<sub>2</sub> S<sub>4</sub> /CC electrode showed an increased capacity from 483 C g<sup>-1</sup> to 841 C g<sup>-1</sup> at 10 mA cm<sup>-2</sup> with excellent rate performance and stable cycling performance, which was superior to the CoNi<sub>2</sub> S<sub>4</sub> /CC electrode activated by NaBH<sub>4</sub> reduction. Anion exchange was beneficial for enhancing the crystallinity, retaining the adhesion of nanoarrays, and realizing low resistance nature in a mild route. The as-assembled CoNi<sub>2</sub> S<sub>4</sub> /CC//activated CC hybrid supercapacitor delivered a high areal capacitance of 1.28 F cm<sup>-2</sup> at 5 mA cm<sup>-2</sup> , and achieved an energy density of 0.58 mWh cm<sup>-2</sup> at a power density of 4.5 mW cm<sup>-2</sup> with excellent cycle stability with 90.6 % capacity retention after 10000 cycles. Supercapacitor ; Capacitance ; Electrode ; Crystallinity ; Power density ; Electrochemistry ; Materials science ; Ion ; Chemical engineering ; Activated carbon ; Nanotechnology ; Analytical Chemistry (journal) ; Chemistry ; Composite material ; Physical chemistry ; Chromatography ; Power (physics) ; Thermodynamics ; Organic chemistry Supercapacitor Materials and Fabrication ; Advancements in Battery Materials ; Electrocatalysts for Energy Conversion
Authors: Rubén Álvarez‐Yebra | Ricard López‐Coll | Núria Clos‐Garrido | David Lozano | Agustí Lledó
Source: Israel Journal of Chemistry (article, 2023-07-06)
Field: Chemistry — Organic Chemistry

Calix[5]arene Self‐Folding Cavitands: A New Family of Bio‐Inspired Receptors with Enhanced Induced Fit Behavior Abstract Self‐folding cavitands represent the quintessential form of bioinspired synthetic receptors, featuring deep hydrophobic cavities that engage in host‐guest chemistry reminiscent of that operating in biomolecules. Although remarkable proof‐of‐concept applications have been reported, the narrow and rigid spaces of the legacy resorcin[4]arene derived hosts constitute a liability towards the development of specific applications in catalysis, sensing or sequestration. While notable efforts to expand the size of the cavities have been reported, the development of confined spaces reproducing the highly adaptable nature of biological receptors is a largely unaddressed issue. This review summarizes the development of a new family of calix[5]arene derived self‐folding cavitands displaying enhanced induced fit and conformational selection phenomena. Our approach capitalizes on hydrogen bonding preorganization rather than the covalent restriction approaches customary of conventional supramolecular chemistry. Chemistry ; Supramolecular chemistry ; Folding (DSP implementation) ; Biomolecule ; Calixarene ; Nanotechnology ; Molecular recognition ; Hydrogen bond ; Host–guest chemistry ; Combinatorial chemistry ; Molecule ; Organic chemistry ; Biochemistry Supramolecular Chemistry and Complexes ; Molecular Sensors and Ion Detection ; Crystallography and molecular interactions
Authors: Liangyu Qian | Priyesh Mohanty | Arul Jayaraman | Jeetain Mittal | Xuejun Zhu
Source: Journal of Biological Chemistry (article, 2023-12-23)
Field: Materials Science — Materials Chemistry

Specific residues and conformational plasticity define the substrate specificity of short-chain dehydrogenases/reductases Short-chain dehydrogenases/reductases (SDRs) are one of the most prevalent enzyme families distributed among the sequenced microorganisms. Despite the presence of a conserved catalytic tetrad and high structural similarity, these enzymes exhibit different substrate specificities. The insufficient knowledge regarding the amino acids underlying substrate specificity hinders the understanding of the SDRs' roles in diverse and significant biological processes. Here, we performed bioinformatic analysis, molecular modeling, and mutagenesis studies to identify the key residues that regulate the substrate specificities of two homologous microbial SDRs (i.e., DesE and KduD). Further, we investigated the impact of altering the physicochemical properties of these amino acids on enzyme activity. Interestingly, molecular dynamics simulations also suggest a critical role of enzyme conformational flexibility in substrate recognition and catalysis. Overall, our findings improve the understanding of microbial SDR substrate specificity and shed light on future rational design of more efficient and effective biocatalysts. Substrate specificity ; Chain (unit) ; Substrate (aquarium) ; Biochemistry ; Chemistry ; Plasticity ; Stereochemistry ; Biophysics ; Crystallography ; Biology ; Enzyme ; Materials science ; Physics Enzyme Structure and Function ; Biochemical and Molecular Research ; Protein Structure and Dynamics
Authors: Julia C. Bulmahn | Andrey N. Kuzmin | Carol Parker | Robert J. Genco | Hilliard L. Kutscher | Paras N. Prasad
Source: Chemical & Biomedical Imaging (article, 2023-08-21)
Field: Materials Science — Materials Chemistry

Upconversion Nanoparticles as Imaging Agents for Dental Caries Dental caries (cavities) is the most prevalent disease worldwide; however, current detection methods suffer from issues associated with sensitivity, subjective interpretations, and false positive identification of carious lesions. Therefore, there is a great need for the development of more sensitive, noninvasive imaging methods. The 30 nm core@shell NaYF<sub>4</sub>; Yb20%, Er2%@NaYF<sub>4</sub> upconversion nanoparticles (UCNPs), exhibiting strong upconversion emission from erbium upon excitation at 975 nm, were used in the imaging of locations of demineralized enamel and oral biofilm formation for the detection of dental caries. UCNPs were modified with poly(acrylic acid) (PAA) or poly-d-lysine (PDL), and targeting peptides were conjugated to their surface with affinity for either hydroxyapatite (HA), the material dentin is composed of, or the caries causing bacteria <i>Streptococcus mutans</i>. A statistical difference in the binding of targeted vs nontargeted UCNPs to HA was observed after 15 min, using both upconversion fluorescence of UCNP (<i>p</i> < 0.001) and elemental analysis (<i>p</i> = 0.0091). Additionally, using the HA targeted UCNPs, holes drilled in the enamel of bovine teeth with diameters of 1.0 and 0.5 mm were visible by the green emission after a 20 min incubation with no observable nonspecific binding. A statistical difference was also observed in the binding of targeted versus nontargeted UCNPs to <i>S. mutans</i> biofilms. This difference was observed after 15 min, using the fluorescence measurements (<i>p</i> = 0.0125), and only 10 min (<i>p</i> < 0.001) using elemental analysis via ICP-OES measurements of Y<sup>3+</sup> concentration present in the biofilms. These results highlight the potential of these UCNPs for use in noninvasive imaging diagnosis of oral disease. Streptococcus mutans ; Enamel paint ; Fluorescence ; Photon upconversion ; Chemistry ; Biofilm ; Dentin ; Nanoparticle ; Nuclear chemistry ; Dentistry ; Materials science ; Nanotechnology ; Bacteria ; Medicine ; Optics Luminescence Properties of Advanced Materials ; Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics
Authors: Baptiste Neil | Lamine Saadi | Louis Fensterbank | Clément Chauvier
Source: Angewandte Chemie (article, 2023-06-07)
Field: Chemistry — Organic Chemistry

Organopotassium‐Catalyzed Silylation of Benzylic C(<i>sp</i><sup>3</sup>)−H Bonds Abstract Benzylsilanes have found increasing applications in organic synthesis as bench‐stable synthetic intermediates, yet are mostly produced by stoichiometric procedures. Catalytic alternatives based on the atom‐economical silylation of benzylic C( sp 3 )−H bonds remain scarcely available as specialized directing groups and catalytic systems are needed to outcompete the kinetically‐favored silylation of C( sp 2 )−H bonds. Herein, we describe the first general and catalytic‐in‐metal undirected silylation of benzylic C( sp 3 )−H bonds under ambient, transition metal‐free conditions using stable tert ‐butyl‐substituted silyldiazenes ( t Bu−N=N−SiR 3 ) as silicon source. The high activity and selectivity of the catalytic system, exemplified by the preparation of various mono‐ or gem ‐bis benzyl(di)silanes, originates from the facile generation of organopotassium reagents, including tert ‐butylpotassium. Silylation ; Silanes ; Catalysis ; Chemistry ; Reagent ; Transition metal ; Selectivity ; Silicon ; Combinatorial chemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Catalytic Cross-Coupling Reactions ; Organoboron and organosilicon chemistry
Authors: Kevin L. Sack | Nicolas Mandel | Nicola M. Pugno | Deon Bezuidenhout | Georges Limbert | Francesco Moscato | Neil H. Davies | Thomas Franz | Tamer Abdalrahman
Source: Meccanica (article, 2023-07-01)
Field: Materials Science — Biomaterials

Micromechanical homogenization of a hydrogel-filled electrospun scaffold for tissue-engineered epicardial patching of the infarcted heart: a feasibility study Abstract For tissue engineering applications, accurate prediction of the effective mechanical properties of tissue scaffolds is critical. Open and closed cell modelling, mean-field homogenization theory, and finite element (FE) methods are theories and techniques currently used in conventional homogenization methods to estimate the equivalent mechanical properties of tissue-engineering scaffolds. This study aimed at developing a formulation to link the microscopic structure and macroscopic mechanics of a fibrous electrospun scaffold filled with a hydrogel for use as an epicardial patch for local support of the infarcted heart. The macroscopic elastic modulus of the scaffold was predicted to be 0.287 MPa with the FE method and 0.290 MPa with the closed-cell model for the realistic fibre structure of the scaffold, and 0.108 MPa and 0.540 MPa with mean-field homogenization for randomly oriented and completely aligned fibres. The homogenized constitutive description of the scaffold was implemented for an epicardial patch in a FE model of a human cardiac left ventricle to assess the effects of patching on myocardial mechanics and ventricular function in the presence of an infarct. Epicardial patching was predicted to reduce maximum myocardial stress in the infarcted LV from 19 kPa (no patch) to 9.5 kPa (patch) and to marginally improve the ventricular ejection fraction from 40% (no patch) to 43% (patch). This study demonstrates the feasibility of homogenization techniques to represent complex multiscale structural features in a simplified but meaningful and effective manner. Homogenization (climate) ; Materials science ; Scaffold ; Biomedical engineering ; Tissue engineering ; Finite element method ; Composite material ; Structural engineering ; Medicine Electrospun Nanofibers in Biomedical Applications ; Tissue Engineering and Regenerative Medicine ; Elasticity and Material Modeling
Authors: Estibaliz Ruiz‐Bilbao | Amaia Iturrospe | Santiago Reinoso | Beñat Artetxe | Garikoitz Beobide | Leire San Felices | Luís Lezama | Juan M. Gutiérrez‐Zorrilla | Shaza Darwish | Debobroto Sensharma | Michael J. Zaworotko
Source: Angewandte Chemie International Edition (article, 2023-06-15)
Field: Chemistry — Inorganic Chemistry

Consecutive Single‐Crystal‐to‐Single‐Crystal Isomerization of Novel Octamolybdate Anions within a Microporous Hybrid Framework with Robust Water Sorption Properties The 3D hybrid framework [{Cu(cyclam)}<sub>3</sub> (κ-Mo<sub>8</sub> O<sub>27</sub> )] ⋅ 14H<sub>2</sub> O (1) (cyclam=1,4,8,11-tetraazacyclotetradecane) undergoes sequential single-crystal-to-single-crystal transformations upon heating to afford two different anhydrous phases (2 a and 3 a). These transitions modify the framework dimensionality and enable the isomerization of κ-octamolybdate (κ-Mo<sub>8</sub> ) anions into λ (2 a) and μ (3 a) forms through metal migration. Hydration of 3 a involves condensation of one water molecule to the cluster to afford the γ-Mo<sub>8</sub> isomer in 4, which dehydrates back into 3 a through the 6 a intermediate. In contrast, 2 a reversibly hydrates to form 5, exhibiting the same Mo<sub>8</sub> cluster as that of 1. It is remarkable that three of the Mo<sub>8</sub> clusters (κ, λ and μ) are new and that up to three different microporous phases can be isolated from 1 (2 a, 3 a, and 6 a). Water vapor sorption analyses show high recyclability and the highest uptake values for POM-based systems. The isotherms display an abrupt step at low humidity level desirable for humidity control devices or water harvesting in drylands. Microporous material ; Cyclam ; Sorption ; Isomerization ; Single crystal ; Anhydrous ; Cluster (spacecraft) ; Chemistry ; Sodalite ; Crystal (programming language) ; Crystallography ; Materials science ; Physical chemistry ; Adsorption ; Zeolite ; Organic chemistry ; Metal ; Catalysis Metal-Organic Frameworks: Synthesis and Applications ; Polyoxometalates: Synthesis and Applications ; Advanced Photocatalysis Techniques