jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Rim Mheich | Mădălina Petcu | Raafat Talhouk
Source: Communications on Pure &amp Applied Analysis (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

On the Logarithmic Cahn-Hilliard Equation with General Proliferation Term Our aim in this article is to study the well-posedness of the generalized logarithmic nonlinear Cahn-Hilliard equation with regularization and proliferation terms. We are interested in studying the asymptotic behavior, in terms of finite-dimensional attractors, of the dynamical system associated with the problem and majorate the rate of convergence between the solutions of the Cahn-Hilliard equation and the regularized one. Additionally, we present some further regularity results and subsequently prove a strict separation property of the solution. Finally, we provide some numerical simulations to compare the solution with and without the regularization term, and more. Cahn–Hilliard equation ; Term (time) ; Logarithm ; Mathematics ; Mathematical physics ; Physics ; Mathematical analysis ; Applied mathematics ; Partial differential equation Solidification and crystal growth phenomena ; Fluid Dynamics and Thin Films ; Differential Equations and Numerical Methods
Authors: Matteo Massaro | Adolfo del Campo
Source: arXiv (Cornell University) (preprint, 2024-10-07)
Field: Chemistry — Spectroscopy

Spatial Form Factor for Point Patterns: Poisson Point Process, Coulomb Gas, and Vortex Statistics Point processes have broad applications in science and engineering. In physics, their use ranges from quantum chaos to statistical mechanics of many-particle systems. We introduce a spatial form factor (SFF) for the characterization of spatial patterns associated with point processes. Specifically, the SFF is defined in terms of the averaged even Fourier transform of the distance between any pair of points. We focus on homogeneous Poisson point processes and derive the explicit expression for the SFF in $d$-spatial dimensions. The SFF can then be found in terms of the even Fourier transform of the probability distribution for the distance between two independent and uniformly distributed random points on a $d$-dimensional ball, arising in the ball line picking problem. The relation between the SFF and the set of $n$-order spacing distributions is further established. The SFF is analyzed in detail for $d=1,2,3$ and in the infinite-dimensional case, as well as for the $d$-dimensional Coulomb gas, as an interacting point process. As a physical application, we describe the spontaneous vortex formation during Bose-Einstein condensation in finite time recently studied in ultracold atom experiments and use the SFF to reveal the stochastic geometry of the resulting vortex patterns. In closing, we also introduce a generalization of the SFF applicable to arbitrary sets in a metric space. Coulomb ; Homogeneous ; Factor (programming language) ; Point process ; Process (computing) ; Point (geometry) ; Poisson distribution ; Physics ; Statistical physics ; Mathematics ; Computer science ; Quantum mechanics ; Geometry ; Statistics Adsorption, diffusion, and thermodynamic properties of materials
Authors: Junqing Xu
Source: arXiv (Cornell University) (preprint, 2024-08-22)
Field: Materials Science — Materials Chemistry

Spin relaxation in graphite due to spin-orbital-phonon interaction from first-principles density-matrix approach We predict "intrinsic" spin relaxation times ($T_{1}$) of graphite due to spin-orbit-phonon interaction, i.e., the combination of spin-orbit coupling and electron-phonon interaction, using our developed first-principles density-matrix approach. We obtain ultralong $T_{1}$, e.g., $\sim$600 ns at 300 K, which leads to ultralong in-plane spin diffusion length $\sim$110 $μ$m within the drift-diffusion model. Our prediction sets the upper bound of $T_{1}$ of graphite at each given temperature and Fermi level. The anisotropy ratios of $T_{1}$ or values of $T_{1z}/T_{1x}$ are found small and around 0.6. We examine the applicability of the well-known Elliot-Yafet (EY) relation, which declares that spin relaxation rate $T_{1α}^{-1}$ ($α=x,y,z$) is proportional to the product of the ensemble average of spin mixing parameter $\left\langle b_α^{2}\right\rangle $ and carrier relaxation rate $τ_{p}^{-1}$. Our numerical tests suggest that the EY relation works qualitatively if the degeneracy threshold $t^{\mathrm{deg}}$ for evaluating $b_α^{2}$ is elatively large (not much smaller than or comparable to $k_{B}T$), e.g., $10^{-3}$ eV or larger, but fails if $t^{\mathrm{deg}}$ is too tiny (much smaller than $k_{B}T$), e.g., $10^{-6}$ eV or smaller. Condensed matter physics ; Spin (aerodynamics) ; Phonon ; Relaxation (psychology) ; Spin density ; Physics ; Graphite ; Matrix (chemical analysis) ; Materials science ; Medicine ; Thermodynamics Graphite, nuclear technology, radiation studies
Authors: Charlotte Pignol | Antonio Ortu | L. Nicolas | Virginia D’Auria | Sébastien Tanzilli | T. Chanelière | Mikael Afzelius | Jean Etesse
Source: arXiv (Cornell University) (preprint, 2024-08-04)
Field: Materials Science — Materials Chemistry

Decoherence induced by dipole-dipole couplings between atomic species in rare-earth ion-doped Y$_2$SiO$_5$ Rare-earth ion doped crystals are state-of-the-art platforms for processing quantum information, particularly thanks to their excellent optical and spin coherence properties at cryogenic temperatures. Experimental observations have shown that the application of a static magnetic bias field significantly improves the coherence times in the rare-earth ions ensemble, but only a few studies have focused on its the dependency as a function of both magnetic field direction and amplitude. This is especially true for magnetic field amplitudes under the mT, and for low magnetic dipole moment ions. In this paper, we investigate the relationship between the magnetic field parameters and the decoherence caused by magnetic dipole-dipole coupling with the nearest neighbors nuclear spins in the crystal. The primary non-Kramers rare-earth ions investigated here are europium and praseodymium, but we also extend our study to the ytterbium Kramers ion due to its low magnetic dipole in the mT range. We perform theoretical investigations and simulations of the energy structure and coherence time evolution and identify good correspondences between experimental and simulated spin echo data. This work allows us to pinpoint the most relevant decoherence mechanisms in the considered magnetic field regime, and to predict favorable magnetic configurations. Dipole ; Rare earth ; Quantum decoherence ; Doping ; Ion ; Atomic physics ; Electric dipole transition ; Earth (classical element) ; Physics ; Materials science ; Condensed matter physics ; Chemistry ; Magnetic dipole ; Quantum mechanics ; Quantum ; Mineralogy Luminescence Properties of Advanced Materials ; Solid-state spectroscopy and crystallography ; Glass properties and applications
Authors: Matteo Fornoni
Source: arXiv (Cornell University) (preprint, 2024-02-06)
Field: Materials Science — Materials Chemistry

Maximal regularity and optimal control for a non-local Cahn-Hilliard tumour growth model We consider a non-local tumour growth model of phase-field type, describing the evolution of tumour cells through proliferation in presence of a nutrient. The model consists of a coupled system, incorporating a non-local Cahn-Hilliard equation for the tumour phase variable and a reaction-diffusion equation for the nutrient. First, we establish novel regularity results for such a model, by applying maximal regularity theory in weighted $L^p$ spaces. This technique enables us to prove the local existence and uniqueness of a regular solution, including also chemotaxis effects. By leveraging time-regularisation properties and global boundedness estimates, we further extend the solution to a global one. These results provide the foundation for addressing an optimal distributed control problem, aimed at identifying a suitable therapy guiding the tumour towards a predefined target. Specifically, we prove the existence of an optimal therapy and, by studying the Fréchet-differentiability of the control-to-state operator and introducing the adjoint system, we derive first-order necessary optimality conditions. Cahn–Hilliard equation ; Growth model ; Mathematics ; Applied mathematics ; Control (management) ; Mathematical economics ; Economics ; Control theory (sociology) ; Mathematical analysis Solidification and crystal growth phenomena
Authors: Ilaria Sandei | Thembaninkosi G. Gaule | Matthew Batchelor | Emanuele Paci | Yi‐Yeoun Kim | Alexander N. Kulak | Darren C. Tomlinson | Fiona C. Meldrum
Source: Biomaterials Science (article, 2024-01-01)
Field: Materials Science — Biomaterials

Phage display identifies Affimer proteins that direct calcium carbonate polymorph formation A key factor in biomineralization is the use of organic molecules to direct the formation of inorganic materials. However, identification of molecules that can selectively produce the calcium carbonate polymorphs calcite or aragonite has proven extremely challenging. Here, we use a phage display approach to identify proteins - rather than the short peptides typically identified using this method - that can direct calcium carbonate formation. A 1.3 × 10<sup>10</sup> library of Affimer proteins was displayed on modified M13 phage, where an Affimer is a ≈13 kDa protein scaffold that displays two variable regions of 9-13 residues. The phage displaying the Affimer library were then screened in binding assays against calcite and aragonite at pH 7.4, and four different strongly-binding proteins were identified. The two aragonite-binding proteins generated aragonite when calcium and magnesium ions were present at a 1 : 1 ratio, while the calcite-binding proteins produce magnesium-calcite under the same conditions. Calcite alone formed in the presence of all four proteins in the absence of magnesium ions. In combination with molecular dynamics simulations to evaluate the conformations of the proteins in solution, this work demonstrates the importance of conformation in polymorph control, and highlights the importance of magnesium ions, which are abundant in seawater, to reduce the energetic barriers associated with aragonite formation. Calcium carbonate ; Chemistry ; Calcium ; Phage display ; Carbonate ; Biophysics ; Biomineralization ; Crystallography ; Biochemistry ; Biology ; Astrobiology ; Organic chemistry Calcium Carbonate Crystallization and Inhibition ; Enzyme function and inhibition ; Enzyme Structure and Function
Authors: Dongmei Huang | Shikui Tu
Source:  (article, 2024-12-03)
Field: Materials Science — Materials Chemistry

MulMol: Transformer-based Multi-Task Molecular Representation Learning Molecular representations are crucial for accurately predicting molecular properties and are fundamental in drug design and related fields. Recently, self-supervised models have leveraged large-scale unlabeled molecular data, with transformers extending learning capabilities. However, existing frameworks predominantly rely on training data for understanding molecular structures, leading to limited generalization on diverse downstream tasks. Moreover, these models often fail to integrate molecular property knowledge effectively, further constraining their ability to generalize. To address these limitations, we propose a multi-task pre-training strategy, MulMol, which combines masked molecular structure reconstruction with property reconstruction, and incorporates contrastive learning to enhance performance. Furthermore, we introduce a similarity comparison task to ensure that the model maintains property consistency despite structural deficiencies at different positions. Evaluations on 11 benchmark datasets demonstrate that MulMol outperforms existing baselines in molecular property prediction across various domains, offering a robust AI-driven tool for drug discovery. The source code is publicly accessible on https://github.com/CMACH508/MulMol. Computer science ; Transformer ; Task (project management) ; Representation (politics) ; Artificial intelligence ; Natural language processing ; Engineering ; Electrical engineering ; Systems engineering ; Voltage Machine Learning in Materials Science ; Machine Learning in Bioinformatics
Authors: Joina Gunjan Singh | Ankit Kumar Singh | Nurul Hidayah Mohamad Idris | Nattasa Kitchawengkul | Purim Jarujamrus | Hooi Ling Lee | Maria Grishina | Nadezhda Palko | Prateek Pathak | Amita Verma
Source: Discover Nano (article, 2024-12-02)
Field: Materials Science — Materials Chemistry

Citric acid based (CQDs/TiO2) nanocomposites against SARS-COV-2: theoretical, photocatalytic and computational studies In the last decade, carbon quantum dots (CQDs), a novel class of carbon-based nanomaterials, have received increasing attention due to their distinct properties. Carbon Quantum Dots/Titanium Dioxide (CQDs/TiO<sub>2</sub>) Nanocomposites were reported as potent compounds against SARS-COV-2. In this manuscript, citric acid is the carbon precursor used to synthesize carbon quantum dots (CQDs). Using a green approach, the synthesized CQD fabricates the Carbon Quantum Dots/Titanium Dioxide (CQDs/TiO2) Nanocomposites. Synthesized composites were characterized by using a UV-visible spectrophotometer, Fourier-transformed infrared (FTIR) spectrometry, X-ray diffractometry (XRD), and Scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX). Methylene blue was used to check the Photocatalytic activity of synthesized (CQDs/TiO<sub>2</sub>) nanocomposites of different concentrations. Computational modeling of agglomerates of CQD and TiO2 nanoparticles with the formula TiO<sub>2</sub>…….. Ti<sub>253</sub>O<sub>506</sub> demonstrated two stages of the nanocomposite formation, including the formation of agglomerates with the neutral and salt-like structures with the total gain in the Gibbs free energy - 38.397 kcal/mole. In silico, Molecular docking studies of citric acid were evaluated against SARS-COV-2 protein to understand their mechanism and key amino acid interactions along with standard drug remdesivir. The photocatalytic activity of CQDs/TiO<sub>2</sub> showed extremely promising results. Based on this study, the proposed mechanism of action of these compounds is reported. A detailed investigation of CQDs/TiO<sub>2</sub> against SARS-CoV-2 is needed, which is another part of the research in our next manuscript. Nanocomposite ; Photocatalysis ; Titanium dioxide ; Nanomaterials ; Citric acid ; Materials science ; Fourier transform infrared spectroscopy ; Nuclear chemistry ; Chemical engineering ; Nanotechnology ; Chemistry ; Organic chemistry ; Composite material ; Catalysis Carbon and Quantum Dots Applications ; Advanced Nanomaterials in Catalysis ; Nanocluster Synthesis and Applications
Authors: Sana Shamim | Ajmal Khan | Mahwish Akhtar | Nighat Shafi | Tehseen Quds | Sabahat Naeem | Rabya Munawar
Source: RADS Journal of Pharmacy and Allied Health Sciences (article, 2024-03-30)
Field: Chemistry — Organic Chemistry

Synthesis and Characterization of C-3 Modified Gemifloxacin Derivatives as Potential Anti-Urease and Antimicrobial Agents Background: Quinolones derivatives have been clinically effective and are used to treat bacterial infections in either community or hospital environments. In current circumstances, acquired microbial resistance (AMR) have gained profound interest for investigators due to irregular/ misuse of antibiotics. Objective: In order to overwhelm the resistance and increase the effectiveness, gemifloxacin-H2 receptor antagonist (cimetidine, famotidine and ranitidine) carboxamide derivatives were designed and synthesized by means of structural modifications at the C-3 position of gemifloxacin (GMFX), an important member of fluoroquinolone class. Method: Synthesis method allows incorporating number of substituents (cimetidine, famotidine and ranitidine)on carboxylic group of gemifloxacinpresent at position C-3. These synthesized derivatives were screened for their physicochemical properties and structurally characterized by spectroscopic analysis (UV-Vis, FT-IR, 1HNMR and Mass). Their in-vitro microbial activities (disk diffusion method) and anti-urease effectiveness were also determined. Results: Three new carboxamide derivatives (G-D21, G-D22 and G-D23) were synthesized in good yield. Spectroscopic studies reveals that the changes occurs at 1645-1639cm-1 attributed to υ(C=O) carb, which was originally observed at 1641-1633 cm-1 in gemifloxacin, indicating formation of amide bond. These derivatives didnot exhibit strong antibacterial response but G-D22 possess highest anti-urease activity (93.5%). Conclusion: Therefore, here we can conclude that these characterized carboxamide derivatives of gemifloxacin didn’t exhibits microbial activities better than gemifloxacin against the studied organisms rather they were potent against the urease enzyme than the parent molecule. Gemifloxacin ; Antimicrobial ; Urease ; Chemistry ; Combinatorial chemistry ; Characterization (materials science) ; Microbiology ; Ciprofloxacin ; Nanotechnology ; Organic chemistry ; Biochemistry ; Antibiotics ; Biology ; Materials science ; Enzyme Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and biological activity ; Synthesis of heterocyclic compounds
Authors: Ümmühan Solmaz
Source:  (article, 2024-05-30)
Field: Chemistry — Inorganic Chemistry

N2,N6-bis((2-Ethoxyphenyl)carbamothioyl)pyridine-2,6-dicarboxamide: Molecular Crystal Structure, Supramolecular Architecture, Hirshfeld Surface Analysis and Interaction Energies The compound N2,N6-bis((2-ethoxyphenyl)carbamothioyl)pyridine-2,6-dicarboxamide was synthesized in two steps with high yield, and its structure was comprehensively characterized using various techniques such as elemental analysis, UV-Vis, 1H NMR, and single-crystal X-ray diffraction. It was determined that the crystal lattice of the compound is stabilized by intramolecular and intermolecular hydrogen bonds, as well as C-H⋅⋅⋅π (C16-H16C⋅⋅⋅Cg(2)) and π⋅⋅⋅π (Cg(2)⋅⋅⋅Cg(2), Cg(1)⋅⋅⋅Cg(3)) interactions, and these interactions play a very important role in defining the overall supramolecular crystal structure of the compound. Hirshfeld surface analysis and two-dimensional fingerprint analysis revealed that H···H (43,4%), S⋯H (10,3%), and C⋯H (8,1%) interactions are more prominent compared to other intermolecular interactions and play a significant role in stabilizing the crystal structure of the compound. Additionally, energy framework calculations determined the three-dimensional topology and interaction energies of the primary interactions within the crystal lattice. Observations concluded that the dispersion energy of the compound (-462,385 kJ/mol) has a greater impact compared to other interaction energies. Pyridine ; Supramolecular chemistry ; Crystal structure ; Crystal (programming language) ; Surface (topology) ; Crystallography ; Hydrogen bond ; Chemistry ; Materials science ; Molecule ; Mathematics ; Organic chemistry ; Geometry ; Computer science Crystal structures of chemical compounds ; Crystallography and molecular interactions ; Lanthanide and Transition Metal Complexes
Authors: Manal Abdel Fattah Ezzat | Heba Abdelrasheed Allam | Samy Mohamady | Samar M. Mogheith
Source: Egyptian Journal of Chemistry (article, 2024-05-13)
Field: Chemistry — Organic Chemistry

Overview on synthetic strategies and bioactivities of pyrazolopyridines. There is undeniable evidence that many N-heterocycles exhibit a wide range of biological functions. Recently, derivatives with better bioactivities have been generated by condensing the different heterocycles. Pyrazolopyridines have been able to pique the interest of many researchers among many other condensed heterocycles, due to the wide range of actions they exhibit. Furthermore, each type of condensed heterocycle has been specifically highlighted in this review in terms of design and biological activities. In silico methods and structure-activity relationship have also been discussed wherever reported. Computational biology ; Computer science ; Biochemical engineering ; Biology ; Engineering Synthesis and biological activity
Authors: Gonzalo Valdivieso | Neudo Urdaneta | Bruno Pribanic | Ronald Vargas | Rafael E. Rodríguez‐Lugo
Source: Chemical Papers (article, 2024-10-04)
Field: Materials Science — Materials Chemistry

10-[(4-Cyanobenzylidene)]-Anthracen-9(10H)-One: syntheses, characterization and application in UV light detection Abstract In this work, the compound 10-[(4-cyanobenzylidene)]-anthracen-9(10 H )-one ( 1 ) has been synthesized from the corresponding anthrone and 4-cyanobenzaldehyde. It has been characterized by nuclear magnetic resonance (NMR), infrared spectroscopy (IR), high-resolution mass spectroscopy (HRMS) and single-crystal X-ray diffraction (XRD) analysis. Moreover, square wave voltammetry (SWV) was performed to determine the HOMO and LUMO potential levels of the anthrone derivative 1 , which indicates that sensitization of TiO 2 -based electrodes is thermodynamically feasible. Therefore, this characteristic of compound 1 allowed its incorporation in a Grätzel-type solar cell. Photocurrent density measurements under UV irradiation are proportional to the light source intensity, and the operational parameters of the photoelectrochemical cell are relatively stable over time. In fact, the sensitivity of the generated photocurrent normalized by the supplied irradiance for TiO 2 - 1 (7.73 µA/mW) as a photoanode is higher than that of TiO 2 alone (5.14 µA/mW), indicating the improvement that 1 provides to TiO 2 with respect to UV light detection. The higher photocurrent and the improved stability due to the implementation of 1 are very promising for possible applications as a sensitizer for UV light intensity sensors in dye-sensitized solar cells (DSSC). Characterization (materials science) ; Chemistry ; Environmental chemistry ; Materials science ; Nanotechnology Photochromic and Fluorescence Chemistry ; TiO2 Photocatalysis and Solar Cells ; Organic Chemistry Cycloaddition Reactions
Authors: Pierre Braunstein
Source: Comptes Rendus Chimie (review, 2024-09-18)
Field: Chemistry — Organic Chemistry

Synthesis and Applications in Chemistry and Materials (ed. A. J. L. Pombeiro, K. T. Mahmudov and M. F. C. Guedes da Silva), Series on Chemistry, Energy and the Environment, vol. 11–14, World Scientific Publishing (March 2024): a review Critical review of four new volumes in the book series “Series on Chemistry, Energy and the Environment” (World Scientific Publishing, Singapore): Synthesis and Applications in Chemistry and Materials , 4 volumes, 2100 pages (March 2024). https://doi.org/10.1142/13309 . Volume 11: Metal Coordination and Nanomaterials Volume 12: Enzymatic and Organic Systems Volume 13: Metal Complex Catalytic Systems and Materials Volume 14: Biomass and Waste Valorisation, Functional Materials, Energy Conversion and Supercritical Systems These volumes were edited by Armando J. L. Pombeiro (Universidade de Lisboa, Portugal), Kamran T. Mahmudov (Universidade de Lisboa, Portugal) and M. Fátima C. Guedes da Silva (Universidade de Lisboa, Portugal). Chemistry ; Series (stratigraphy) ; Organic chemistry ; Biology Chemical Synthesis and Reactions