jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Irfan Haider Abidi | Sindhu Priya Giridhar | Jonathan O. Tollerud | Jake Limb | Aishani Mazumder | Edwin L. H. Mayes | Billy J. Murdoch | Chenglong Xu | Ankit Bhoriya | Abhishek Ranjan | Taimur Ahmed | Yongxiang Li | Jeffrey A. Davis | Cameron L. Bentley | Salvy P. Russo | Enrico Della Gaspera | Sumeet Walia
Source: arXiv (Cornell University) (preprint, 2023-11-14)
Field: Materials Science — Materials Chemistry

Intrinsic defect engineering of CVD grown monolayer MoS$_2$ for tuneable functional nanodevices Defects in atomically thin materials can drive new functionalities and expand applications to multifunctional systems that are monolithically integrated. An ability to control formation of defects during the synthesis process is an important capability to create practical deployment opportunities. Molybdenum disulfide (MoS$_2$), a two-dimensional (2D) semiconducting material harbors intrinsic defects that can be harnessed to achieve tuneable electronic, optoelectronic, and electrochemical devices. However, achieving precise control over defect formation within monolayer MoS$_2$, while maintaining the structural integrity of the crystals remains a notable challenge. Here, we present a one-step, in-situ defect engineering approach for monolayer MoS$_2$ using a pressure dependent chemical vapour deposition (CVD) process. Monolayer MoS$_2$ grown in low-pressure CVD conditions (LP-MoS$_2$) produces sulfur vacancy (Vs) induced defect rich crystals primarily attributed to the kinetics of the growth conditions. Conversely, atmospheric pressure CVD grown MoS$_2$ (AP-MoS$_2$) passivates these Vs defects with oxygen. This disparity in defect profiles profoundly impacts crucial functional properties and device performance. AP-MoS$_2$ shows a drastically enhanced photoluminescence, which is significantly quenched in LP-MoS$_2$ attributed to in-gap electron donor states induced by the Vs defects. However, the n-doping induced by the Vs defects in LP-MoS$_2$ generates enhanced photoresponsivity and detectivity in our fabricated photodetectors compared to the AP-MoS$_2$ based devices. Defect-rich LP-MoS$_2$ outperforms AP-MoS$_2$ as channel layers of field-effect transistors (FETs), as well as electrocatalytic material for hydrogen evolution reaction (HER). This work presents a single-step CVD approach for in-situ defect engineering in monolayer MoS$_2$ and presents a pathway to control defects in other monolayer material systems. Molybdenum disulfide ; Monolayer ; Materials science ; Chemical vapor deposition ; Optoelectronics ; Photoluminescence ; Nanotechnology ; Doping ; Transistor ; Vacancy defect ; Field-effect transistor ; Passivation ; Layer (electronics) ; Voltage ; Chemistry ; Electrical engineering ; Crystallography 2D Materials and Applications ; Nanowire Synthesis and Applications ; Chalcogenide Semiconductor Thin Films
Authors: Patricia Poths | Santiago Vargas | Philippe Sautet | Anastassia N. Alexandrova
Source: ChemRxiv (preprint, 2023-11-13)
Field: Materials Science — Materials Chemistry

Beyond Boltzmann: thermalization of cluster catalyst ensembles can extend beyond reaction timescales The fluxionality of subnanocluster catalysts is essential for understanding their be- havior at an atomistic level. Up until now, when it is at all considered, fluxionality has been treated primarily thermodynamically, representing relevant isomer populations as their Boltzmann populations. Previous work supported this, suggesting that the Pt7/Al2O3 ensemble should be kinetically accessible within ns, based on the barrier heights for isomerization. In the current work, we explore the isomerization kinetics of gas-phase and surface-supported Pt4Hx clusters, using kMC to explore the evolution of isomer populations with time as a function of temperature. We additionally revisit the previously-obtained Pt7/Al2O3 network. This allows us to determine the temperature- dependent timescales at which the ensembles of these subnanoclusters reach thermal equilibirum. Gas-phase clusters readily thermalize by 350 K, while surface-supported clusters require temperatures between 500-700 K. These thermalization timescales de- pend on how structurally distinct the cluster isomers are within their ensemble. The greater the structural difference there is between low-energy structures, the longer it requires to reach thermal equilibrium. We show that it is essential to compute the barriers for isomerization between low-lying isomers in order to accurately determine either thermalization timescales, or non-equilibrium steady-state populations. Finally, we find that these thermalization timescales can extend to longer than catalytically- relevant timescales, depending on the reaction in question, indicating that isomerization is an essential feature of the reaction coordinate of a catalytic reaction Isomerization ; Thermalisation ; Cluster (spacecraft) ; Chemistry ; Potential energy surface ; Chemical physics ; Reaction coordinate ; Work (physics) ; Catalysis ; Kinetics ; Boltzmann constant ; Thermal ; Thermodynamics ; Statistical physics ; Computational chemistry ; Physics ; Molecule ; Quantum mechanics Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions ; Machine Learning in Materials Science
Authors: Mengen Wang | J. Anibal Boscoboinik | Deyu Lu
Source: The Journal of Physical Chemistry C (article, 2023-07-07)
Field: Chemistry — Inorganic Chemistry

First-Principles Study of <i>n</i>-Butane Monomolecular Cracking and Dehydrogenation on Two-Dimensional-Zeolite Model Systems: Reaction Mechanisms and Effects of Spatial Confinement Two-dimensional (2D) ultrathin (∼0.5 nm) aluminosilicate bilayer films, consisting of hexagonal prisms (a.k.a. double 6-membered rings D6R) with acidic bridging hydroxyl groups exposed on the surface, have been previously synthesized on a Ru(0001) surface as a zeolite model system. These structures are helpful for mimicking zeolite catalysts with D6R building blocks, such as chabazite. We performed density functional theory calculations to investigate the monomolecular cracking and dehydrogenation of n-butane molecules over the acidic hydroxyl groups of the 2D model system and compared the reaction energetics with that in bulk chabazite. The intrinsic activation energy barrier is the highest for dehydrogenation and lowest for central C–C bond cracking in bulk chabazite. The trend of intrinsic energy barriers for dehydrogenation and terminal and central C–C bond cracking is reproduced on the 2D aluminosilicate film. Overall, the activation barriers are higher on the 2D film than in bulk chabazite due to the lack of confinement in the former. We further explored the effects of the zeolite channel size on the n-butane adsorption and monomolecular cracking using different bulk nanoporous zeolite frameworks (TON, MEL, MEI, and VFI). We found that as the confinement of channels decreases, n-butane adsorption becomes weaker, and the intrinsic energy barrier of terminal C–C cracking increases. The activation energy barriers (dehydrogenation and terminal and central C–C cracking) on the 2D bilayer film surface, which may be considered as zeolite cages at the infinite cage size limit, are close to that in VFI with a relatively large channel size. Comparing the reaction pathway of n-butane terminal C–C cracking in 3D nanocages and on the surface of the 2D aluminosilicate film revealed that stabilizing the transition states in the 3D nanocages is responsible for the decrease in the intrinsic energy barriers for bulk zeolites. Chabazite ; Dehydrogenation ; Zeolite ; Microporous material ; Adsorption ; Aluminosilicate ; Activation energy ; Butane ; Materials science ; Cracking ; Density functional theory ; Chemistry ; Chemical engineering ; Physical chemistry ; Catalysis ; Computational chemistry ; Composite material ; Organic chemistry Zeolite Catalysis and Synthesis ; Mesoporous Materials and Catalysis ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Anna L. Neuer | Inge K. Herrmann | Alexander Gogos
Source: ChemRxiv (preprint, 2023-07-12)
Field: Materials Science — Materials Chemistry

Biochemical transformations of inorganic nanomedicines in buffers, cell cultures and organisms The field of nanomedicine is rapidly evolving, with new materials and formulations being reported almost daily. In this respect, inorganic and inorganic-organic composite nanomaterials have gained significant attention. However, the use of new materials in clinical trials and their final approval as drugs has been hampered by several challenges, one of which is the complex and difficult to control nanomaterial chemistry that takes place within the body. Several reviews have summarized investigations on inorganic nanomaterial stability in model body fluids, cell cultures, and organisms, focusing on their degradation as well as the influence of corona formation. However, in addition to these aspects, various chemical reactions of nanomaterials, including phase transformation and/or the formation of new/secondary nanomaterials, have been reported. In this review, we discuss recent advances in our understanding of biochemical transformations of medically relevant inorganic (composite) nanomaterials in environments related to their applications. We provide a refined terminology for the primary reaction mechanisms involved to bridge the gaps between different disciplines involved in this research. Furthermore, we highlight suitable analytical techniques that can be harnessed to explore the described reactions. Finally, we highlight opportunities to utilize them for diagnostic and therapeutic purposes and discuss current challenges and research priorities. Nanomedicine ; Nanotechnology ; Nanomaterials ; Biochemical engineering ; Terminology ; Chemistry ; Materials science ; Engineering ; Nanoparticle Nanoparticles: synthesis and applications
Authors: Subramanian K. R. S. Sankaranarayanan | Suvo Banik | Troy D. Loeffler | Sukriti Manna | Srilok Sriniva | Pierre Darancet | Henry Chan | Alexander Hexemer
Source: Research Square (preprint, 2023-01-19)
Field: Materials Science — Materials Chemistry

A Continuous Action Space Tree search for INverse desiGn (CASTING) Framework for Materials Discovery Action (physics) ; Inverse ; Tree (set theory) ; Space (punctuation) ; Computer science ; Theoretical computer science ; Mathematics ; Physics ; Combinatorics ; Geometry Machine Learning in Materials Science ; X-ray Diffraction in Crystallography ; Crystallization and Solubility Studies
Authors: Pavel Khramtsov | Артем С. Минин | Zarina Galaeva | Elena Mukhlynina | Maria Kropaneva | Mikhail Rayev
Source: ChemRxiv (preprint, 2023-06-13)
Field: Materials Science — Materials Chemistry

Optimization of the diaminobenzidine substrate composition improves the performance of peroxidase-like Prussian Blue nanozymes in colorimetric assays One of the emerging trends in modern analytical and bioanalytical chemistry is the substitution of enzyme labels, such as horseradish peroxidase, with nanozymes — nanoparticles that possess enzyme-like catalytic activity. Since enzymes and nanozymes typically have different catalytic mechanisms, it is expected that the optimal reaction conditions will also differ. The objective of this paper was to optimize the diaminobenzidine (DAB) chromogenic substrate to enhance the performance of Prussian Blue nanozymes in immunostaining applications. We elucidated that enhancers (such as imidazole), which are typically added to commercial DAB substrate solutions to boost the color signal generated by peroxidase, can suppress the activity of nanozymes. This issue can be resolved by optimizing a nanozyme-specific substrate buffer composition. More specifically, we demonstrated that buffers such as citrate, MES, HEPES, and TRIS containing 1.5-2 M NaCl or NH4Cl substantially increase DAB oxidation by Prussian Blue and provide a higher signal than commercial DAB formulations. Moreover, the composition of the substrate solution (type of buffer, ionic strength, additives) affects signal intensity to the same degree as buffer pH. Tuning the substrate buffer composition is, therefore, a simple and efficient way of signal amplification in nanozyme-based assays. Optimized DAB substrate formulations were applied to Prussian Blue-based tissue staining, western blotting assay of immunoglobulins, and dot blot assay of antibodies against SARS-CoV-2. Prussian blue ; Substrate (aquarium) ; Chemistry ; Horseradish peroxidase ; Peroxidase ; Chromogenic ; Combinatorial chemistry ; Chromatography ; Enzyme ; Biochemistry ; Electrode ; Electrochemistry Advanced Nanomaterials in Catalysis ; Advanced biosensing and bioanalysis techniques ; Biosensors and Analytical Detection
Authors: Hang Zhang | Sankaran Sundaresan | Michael A. Webb
Source: ChemRxiv (preprint, 2023-03-22)
Field: Materials Science — Surfaces, Coatings and Films

Molecular Dynamics Investigation of Nanoscale Hydrophobicity of Polymer Surfaces: What Makes Water Wet? The wettability of a polymer surface--related to its hydrophobicity or tendency to repel water--can be crucial for determining its utility, such as for a coating or a purification membrane. While wettability is commonly associated with the macroscopic measurement of a contact angle between surface, water, and air, the molecular physics that underlie these macroscopic observations are not fully known, and anticipating relative behavior of different polymers is challenging. To address this gap in molecular-level understanding, we use molecular dynamics simulations to investigate and contrast interactions of water with six chemically distinct polymers: polytetrafluoroethylene, polyethylene, polyvinyl chloride, poly(methyl methacrylate), Nylon 66, and polyvinyl alcohol. We show that several prospective quantitative metrics for hydrophobicity agree well with experimental contact angles. Moreover, the behavior of water in proximity to these polymer surfaces can be distinguished with analysis of interfacial water dynamics, extent of hydrogen bonding, and molecular orientation--even when macroscopic measures of hydrophobicity are similar. The predominant factor dictating wettability is found to be the extent of hydrogen-bonding between polymer and water, but the precise manifestation of hydrogen-bonding and its impact on surface-water structure varies. In the absence of hydrogen-bonding, other molecular interactions and polymer mechanics control hydrophobic ordering. These results provide new insights into how polymer chemistry specifically impacts water-polymer interactions and translates to surface hydrophobicity. Such factors may facilitate the design or processing of polymer surfaces to achieve targeted wetting behavior, and presented analyses can be useful in studying the interfacial physics of other systems. Wetting ; Polymer ; Contact angle ; Materials science ; Molecular dynamics ; Hydrogen bond ; Chemical physics ; Polyvinyl chloride ; Chemical engineering ; Nanoscopic scale ; Methyl methacrylate ; Nanotechnology ; Polymer chemistry ; Composite material ; Molecule ; Chemistry ; Monomer ; Organic chemistry ; Computational chemistry Surface Modification and Superhydrophobicity ; Phase Equilibria and Thermodynamics
Authors: Pei Zhang | Logan T. Kearney | Debsindhu Bhowmik | Zachary Fox | Amit K. Naskar | John Gounley
Source: arXiv (Cornell University) (preprint, 2023-10-25)
Field: Materials Science — Materials Chemistry

Transferring a molecular foundation model for polymer property predictions Transformer-based large language models have remarkable potential to accelerate design optimization for applications such as drug development and materials discovery. Self-supervised pretraining of transformer models requires large-scale datasets, which are often sparsely populated in topical areas such as polymer science. State-of-the-art approaches for polymers conduct data augmentation to generate additional samples but unavoidably incurs extra computational costs. In contrast, large-scale open-source datasets are available for small molecules and provide a potential solution to data scarcity through transfer learning. In this work, we show that using transformers pretrained on small molecules and fine-tuned on polymer properties achieve comparable accuracy to those trained on augmented polymer datasets for a series of benchmark prediction tasks. Transformer ; Computer science ; Benchmark (surveying) ; Scarcity ; Transfer of learning ; Polymer ; Labeled data ; Artificial intelligence ; Machine learning ; Materials science ; Engineering ; Electrical engineering Machine Learning in Materials Science ; Computational Drug Discovery Methods
Authors: P. D’Angelo | Francesco Tavani | Alessandro Tofoni
Source: Preprints.org (preprint, 2023-08-31)
Field: Chemistry — Inorganic Chemistry

Exploring the Methane to Methanol Oxidation Over Iron and Copper Sites in Metal-Organic Frameworks The direct methane to methanol (MTM) oxidation is a grand challenge in catalysis, with profound economical implications for the modern chemical industry. Bioinspired metal-organic frameworks (MOFs) with active iron and copper sites have been emerging very recently as innovative catalytic platforms to accomplish the MTM conversion under mild conditions. This review discusses the current state of the art regarding the application of MOFs with iron and copper catalytic centers to perform the MTM reaction, with a focus on the diverse spectroscopic techniques used to unveil the electronic and structural properties of the MOF catalysts at a microscopic level. We explore the synthetic strategies employed to incorporate iron and copper sites into different MOF topologies, the efficiency and selectivity of the iron- and copper-bearing MOF catalysts, and the ensuing MTM reaction mechanisms proposed on the basis of spectroscopic characterization supported by theory. In particular, we evidence how the combination of complementary spectroscopic tools probing different regions of the electromagnetic spectrum is particularly useful to reach a satisfactory understanding of the key reaction pathways and intermediates. Finally, we provide a critical perspective on future directions to advance the use of MOFs to accomplish the MTM reaction. Copper ; Catalysis ; Methanol ; Methane ; Metal-organic framework ; Anaerobic oxidation of methane ; Nanotechnology ; Materials science ; Metal ; Chemistry ; Combinatorial chemistry ; Organic chemistry ; Metallurgy Metal-Organic Frameworks: Synthesis and Applications ; Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions
Authors: A. Fert | Ramamoorthy Ramesh | Vincent Garcia | Fèlix Casanova | Manuel Bibès
Source: arXiv (Cornell University) (preprint, 2023-11-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Electrical control of magnetism by electric field and current-induced torques While early magnetic memory designs relied on magnetization switching by locally generated magnetic fields, key insights in condensed matter physics later suggested the possibility to do it electrically. In the 1990s, Slonczewzki and Berger formulated the concept of current-induced spin torques in magnetic multilayers through which a spin-polarized current may switch the magnetization of a ferromagnet. This discovery drove the development of spin-transfer-torque magnetic random-access memories (STT-MRAMs). More recent research unveiled spin-orbit-torques (SOTs) and will lead to a new generation of devices including SOT-MRAMs. Parallel to these advances, multiferroics and their magnetoelectric coupling experienced a renaissance, leading to novel device concepts for information and communication technology such as the MESO transistor. The story of the electrical control of magnetization is that of a dance between fundamental research (in spintronics, condensed matter physics, and materials science) and technology (MRAMs, MESO, microwave emitters, spin-diodes, skyrmion-based devices, components for neuromorphics, etc). This pas de deux led to major breakthroughs over the last decades (pure spin currents, magnetic skyrmions, spin-charge interconversion, etc). As a result, this field has propelled MRAMs into consumer electronics products but also fueled discoveries in adjacent research areas such as ferroelectrics or magnonics. Here, we cover recent advances in the control of magnetism by electric fields and by current-induced torques. We first review fundamental concepts in these two directions, then discuss their combination, and finally present various families of devices harnessing the electrical control of magnetic properties for various application fields. We conclude by giving perspectives in terms of both emerging fundamental physics concepts and new directions in materials science. Spintronics ; Magnetism ; Magnetization ; Condensed matter physics ; Physics ; Spin (aerodynamics) ; Engineering physics ; Magnetic field ; Ferromagnetism ; Quantum mechanics Magnetic and transport properties of perovskites and related materials ; Magnetic properties of thin films ; Multiferroics and related materials
Authors: Tatsuya Takagi
Source: Chem-Bio Informatics Journal (article, 2023-02-19)
Field: Materials Science — Materials Chemistry

How Beneficial or Threatening is Artificial Intelligence? Computer scientists have studied artificial intelligence and machine learning since computers were invented. There have been three waves of developments, in this field. First development, in the 1950s, computer chess and reversiTM, were realized. In the second development, “expert systems” attracted attention and started the “5th Generation Computer Project.” in 1980s. However, the results of both the developments were insufficient (for example, 5th Generation Computer was not created), and the enthusiasm for expecting new type of computers such as artificial intelligence quickly diminished. We are now in the third wave of the AI developments. Will it produce satisfactory results? Will it revolutionize life sciences? In this article, I have tried to answer these questions. Enthusiasm ; Field (mathematics) ; Computer science ; Third wave ; Artificial intelligence ; Expert system ; Data science ; Psychology ; Sociology Machine Learning in Materials Science ; Computational Drug Discovery Methods ; Machine Learning and Data Classification
Authors: Longhui Yu | Shangzhao Li | Tsoh Lam Cheung | Wenchao Liu | Dexiu Yan | Yudai Matsuda | Yusuke Kobayashi | Zhihong Guo | Pei‐Yuan Qian | Hugh Nakamura
Source: ChemRxiv (preprint, 2023-05-25)
Field: Chemistry — Organic Chemistry

Short, Chemoenzymatic Access to Cyctetryptomycin A and B A concise and chemoenzymatic synthesis of cyctetryptomycin A and B (1-2) using a Zr-catalyst and CttpC is reported. The recent discovery of cyctetryptomycin A and B (1-2) and their intriguing neuroprotective activities necessitated scalable synthesis to facilitate structure-activ-ity relationship studies. However, the synthesis of cyctetryptomycin A and B (1-2) solely by chemical reactions has proven to be impractical. Therefore, a novel approach using a short and chemoenzymatic strategy was developed to prepare cyctetryptomycin A and B (1-2) via Zr-catalyzed construction of two consecutive quaternary chiral carbons and CttpC-catalyzed direct oxidative coupling of the tryptophan moiety. Moiety ; Catalysis ; Combinatorial chemistry ; Chemistry ; Stereochemistry ; Oxidative coupling of methane ; Organic chemistry Synthetic Organic Chemistry Methods ; Microbial Natural Products and Biosynthesis ; Catalytic C–H Functionalization Methods