jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ray Miyazaki | Kenji Iida | Shohei Ohno | Tsuyoshi Matsuzaki | Takeyuki Suzuki | Mitsuhiro Arisawa | Jun‐ya Hasegawa
Source: Organometallics (article, 2022-11-21)
Field: Chemistry — Organic Chemistry

Substrate-Assisted Reductive Elimination Determining the Catalytic Cycle: A Theoretical Study on the Ni-Catalyzed 2,3-Disubstituted Benzofuran Synthesis via C–O Bond Activation 2,3-Disubstituted benzofurans with potential for pharmaceutical applications are effectively synthesized by Ni complexes via intramolecular C–O bond activation. The reaction pathway for the full catalytic cycle has been investigated using density functional theory (DFT) calculations. The rate-determining step is the reductive elimination of the product. A key result is that coordination to an alkynyl group of another substrate co-occurs with elimination, which not only improves thermodynamic stability of the product but also determines the reaction pathway of the catalytic cycle. The reductive elimination assisted by the solvent molecules or free ligand results in an endergonic reaction. This result is related to the enhancement of reductive elimination of C–C coupling products by the addition of olefins or alkynes and can be recognized as a self-cocatalytic effect of the substrate. The result adds another viewpoint in the design of catalytic reaction systems with effective catalytic cycles. Reductive elimination ; Chemistry ; Catalytic cycle ; Catalysis ; Intramolecular force ; Benzofuran ; Combinatorial chemistry ; Substrate (aquarium) ; Density functional theory ; Ligand (biochemistry) ; Coupling reaction ; Medicinal chemistry ; Computational chemistry ; Photochemistry ; Stereochemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Cyclopropane Reaction Mechanisms ; Asymmetric Hydrogenation and Catalysis
Authors: Maxime D. Charpentier | Raghunath Venkatramanan | Céline Rougeot | Tom Leyssens | Karen Johnston | Joop H. ter Horst
Source: Molecular Pharmaceutics (article, 2022-12-05)
Field: Chemistry — Spectroscopy

Multicomponent Chiral Quantification with Ultraviolet Circular Dichroism Spectroscopy: Ternary and Quaternary Phase Diagrams of Levetiracetam Chiral molecules are challenging for the pharmaceutical industry because although physical properties of the enantiomers are the same in achiral systems, they exhibit different effects in chiral systems, such as the human body. The separation of enantiomers is desired but complex, as enantiomers crystallize most often as racemic compounds. A technique to enable the chiral separation of racemic compounds is to create an asymmetry in the thermodynamic system by generating chiral cocrystal(s) using a chiral coformer and using the solubility differences to enable separation through crystallization from solution. However, such quaternary systems are complex and require analytical methods to quantify different chiral molecules in solution. Here, we develop a new chiral quantification method using ultraviolet-circular dichroism spectroscopy and multivariate partial least squares calibration models, to build multicomponent chiral phase diagrams. Working on the quaternary system of (<i>R</i>)- and (<i>S</i>)-2-(2-oxopyrrolidin-1-yl)butanamide enantiomers with (<i>S</i>)-mandelic acid in acetonitrile, we measure accurately the full quaternary phase diagram for the first time. By understanding the phase stabilities of the racemic compound and the enantiospecific cocrystal, the chiral resolution of levetiracetam could be designed due to a large asymmetry in overall solubility between both sides of the racemic composition. This new method offers improvements for chiral molecule quantification in complex multicomponent chiral systems and can be applied to other chiral spectroscopy techniques. Enantiomer ; Circular dichroism ; Chiral resolution ; Cocrystal ; Chemistry ; Mandelic acid ; Phase diagram ; Phase (matter) ; Molecule ; Organic chemistry ; Crystallography Molecular spectroscopy and chirality ; Analytical Chemistry and Chromatography ; Crystallization and Solubility Studies
Authors: Douglas Santos Silva | Maurício Maia Ribeiro | Jean da Silva Rodrigues | Alessandro de Castro Corrêa | Dênis Carlos Lima Costa | Heictor Alves de Oliveira Costa | Fernando José Aguirre Ramos da Silva | Alessandro José Gomes dos Santos | Marcelo Henrique Prado da Silva | Roberto Tetsuo Fujiyama
Source: Research Society and Development (article, 2022-02-24)
Field: Materials Science — Polymers and Plastics

Properties of flexural and impact of matrix composites polyester reinforced with short lignocellulosic fibers Composite materials stand out for enabling the development of new materials that are environmentally friendly, whose manufacturing processes and waste are increasingly less harmful, associated with good mechanical properties. In this context, this work sought to investigate the mechanical behavior in flexural and impact of polyester matrix composites with the inclusion of short fibers of sisal, piassava, raffia, mallow and jute arranged randomly. The mechanical properties of flexural were evaluated according to ASTM D 790 and the impact toughness Charpy with the ASTM D 6110 standard. The results showed that when subjected to flexural stresses, the composites presented resistance of 112 .12 MPa for the neat matrix and 35.21; 34.45; 27.29; 25.89 and 20.56 MPa with the inclusion of sisal, piassava, raffia, mallow and jute fibers, respectively. As for the impact test, they showed values of 31.50 kJ/m² for the neat matrix and 57.06; 52.52; 48.03; 38.02; 37.65 kJ/m² with the inclusion of sisal, piassava, raffia, mallow and jute fibers, respectively. Then, the fracture surface of the composites was analyzed with a microscope in order to correlate the fracture aspects with the mechanical properties. Charpy impact test ; Flexural strength ; Composite material ; Materials science ; SISAL ; Context (archaeology) ; Izod impact strength test ; Composite number ; Toughness ; Ultimate tensile strength Natural Fiber Reinforced Composites ; Logistics and Infrastructure Analysis
Authors: Nana Yang | Jingjing Xu | Fan Wang | Fan Yang | Danhong Han | Shengyong Xu
Source: Sensors (review, 2022-07-07)
Field: Chemistry — Physical and Theoretical Chemistry

Thermal Probing Techniques for a Single Live Cell Temperature is a significant factor in determining and characterizing cellular metabolism and other biochemical activities. In this study, we provide a brief overview of two important technologies used to monitor the local temperatures of individual living cells: fluorescence nano-thermometry and an array of micro-/nano-sized thin-film thermocouples. We explain some key technical issues that must be addressed and optimised for further practical applications, such as in cell biology, drug selection, and novel antitumor therapy. We also offer a method for combining them into a hybrid measuring system. Thermocouple ; Key (lock) ; Nanotechnology ; Computer science ; Selection (genetic algorithm) ; Biological system ; Biochemical engineering ; Materials science ; Biomedical engineering ; Biology ; Engineering ; Artificial intelligence thermodynamics and calorimetric analyses ; Thermal properties of materials ; Analytical Chemistry and Sensors
Authors: Gerry Roskam | Bas van de Velde | Andrea Gargano | Isabelle Köhler
Source: LCGC Europe (article, 2022-04-01)
Field: Chemistry — Spectroscopy

Supercritical Fluid Chromatography for Chiral Analysis, Part 2: Applications In the second part of this review article, the recent progress in supercritical fluid chromatography (SFC) for enantiomeric separations is evaluated. With the substantial developments carried out over the past years in instrumentation, columns, and detector hyphenation, the interest in chiral SFC has been steadily growing in various fields. In combination with novel developments in chiral stationary phase chemistries, the enantioselective analysis range has been significantly extended. Several applications reported on the enantioselective separation of drugs and pharmaceutical compounds using chiral SFC are discussed, including pharmaceutical applications, clinical research, forensic toxicology, and environmental sciences. Supercritical fluid chromatography ; Enantioselective synthesis ; Supercritical fluid ; Chiral stationary phase ; Chromatography ; Enantiomer ; Chemistry ; Stationary phase ; Gas chromatography ; Nanotechnology ; High-performance liquid chromatography ; Materials science ; Organic chemistry ; Catalysis Analytical Chemistry and Chromatography ; Chromatography in Natural Products ; Mass Spectrometry Techniques and Applications
Authors: Yikai Wang | Chun Hu | Zhongxiang Li | Dezhi Zheng | Fei Cui | Xiaojun Yang
Source: Applied Sciences (article, 2022-08-18)
Field: Materials Science — Materials Chemistry

Theoretical and Simulation Analysis of Static and Dynamic Properties of MXene-Based Humidity Sensors In this paper, the static and dynamic characteristics of the MXene-based IDE capacitive humidity sensor are investigated through theoretical modeling and simulation. It is found that the capacitance increases according to the thickness of the sensing film within a certain range while stopping increases along with the growth of the thickness when the thickness is over a threshold. When the thickness is at a tiny level, a larger thickness does not lead to a significant increase in the response time due to the diffusion mechanism of water molecules. When the thickness increases to certain extent, there is an evident relationship between the response time and the change of thickness. For the humidity-sensitive film, under the same relative humidity conditions, the capacitance has a positive correlation with temperature, and the response time shows the opposite trend. Subsequent studies on the sensitive mechanisms of MXene materials explain these phenomena and demonstrate the accuracy of the model. This provides a more accurate method for sensor design. The properties of the MXene capacitive humidity sensor can be optimized by changing its structure and adjusting material parameters. Capacitive sensing ; Humidity ; Materials science ; Capacitance ; Relative humidity ; Optoelectronics ; Composite material ; Electrical engineering ; Meteorology ; Engineering ; Chemistry ; Physics MXene and MAX Phase Materials ; Advanced Memory and Neural Computing ; Advanced Sensor and Energy Harvesting Materials
Authors: Veronica G. Reynolds | Devon H. Callan | Kumar Saurabh | Elizabeth Murphy | Kaitlin R. Albanese | Yan‐Qiao Chen | Claire Wu | Eliot Gann | Craig J. Hawker | Baskar Ganapathysubramanian | Christopher M. Bates | Michael L. Chabinyc
Source: Molecular Systems Design & Engineering (article, 2022-01-01)
Field: Materials Science — Materials Chemistry

Simulation-guided analysis of resonant soft X-ray scattering for determining the microstructure of triblock copolymers Resonant soft X-ray scattering (RSoXS) probes structure with chemical sensitivity that is useful for determining the morphology of multiblock copolymers. Copolymer ; Scattering ; Microstructure ; Materials science ; Small-angle X-ray scattering ; Morphology (biology) ; X-ray ; Optics ; Composite material ; Physics ; Polymer Block Copolymer Self-Assembly ; Advanced Polymer Synthesis and Characterization ; Nanoparticle-Based Drug Delivery
Authors: H. Georg Schulze | Shreyas Rangan | Martha Z. Vardaki | Michael W. Blades | Robin F. B. Turner | James M. Piret
Source: Applied Spectroscopy (article, 2022-10-13)
Field: Chemistry — Analytical Chemistry

Two-Dimensional Clustering of Spectral Changes for the Interpretation of Raman Hyperspectra Two-dimensional correlation spectroscopy (2D-COS) is a technique that permits the examination of synchronous and asynchronous changes present in hyperspectral data. It produces two-dimensional correlation coefficient maps that represent the mutually correlated changes occurring at all Raman wavenumbers during an implemented perturbation. To focus our analysis on clusters of wavenumbers that tend to change together, we apply a <i>k</i>-means clustering to the wavenumber profiles in the perturbation domain decomposition of the two-dimensional correlation coefficient map. These profiles (or trends) reflect peak intensity changes as a function of the perturbation. We then plot the co-occurrences of cluster members two-dimensionally in a manner analogous to a two-dimensional correlation coefficient map. Because wavenumber profiles are clustered based on their similarity, two-dimensional cluster member spectra reveal which Raman peaks change in a similar manner, rather than how much they are correlated. Furthermore, clustering produces a discrete partitioning of the wavenumbers, thus a two-dimensional cluster member spectrum exhibits a discrete presentation of related Raman peaks as opposed to the more continuous representations in a two-dimensional correlation coefficient map. We demonstrate first the basic principles of the technique with the aid of synthetic data. We then apply it to Raman spectra obtained from a polystyrene perchlorate model system followed by Raman spectra from mammalian cells fixed with different percentages of methanol. Both data sets were designed to produce differential changes in sample components. In both cases, all the peaks pertaining to a given component should then change in a similar manner. We observed that component-based profile clustering did occur for polystyrene and perchlorate in the model system and lipids, nucleic acids, and proteins in the mammalian cell example. This confirmed that the method can translate to "real world" samples. We contrast these results with two-dimensional correlation spectroscopy results. To supplement interpretation, we present the cluster-segmented mean spectrum of the hyperspectral data. Overall, this technique is expected to be a valuable adjunct to two-dimensional correlation spectroscopy to further facilitate hyperspectral data interpretation and analysis. Raman spectroscopy ; Wavenumber ; Perturbation (astronomy) ; Cluster analysis ; Chemistry ; Spectral line ; Correlation coefficient ; Statistical physics ; Physics ; Mathematics ; Optics ; Statistics ; Quantum mechanics Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Metabolomics and Mass Spectrometry Studies
Authors: Yunhua Wu | Dongmei Gan | Xuefeng Leng | Wenwu He | Xiuqiong Zhang | Chong Li | Xiaobo Gu | Ying Hu | Shijian Du | Yongtao Han
Source: Journal of Oleo Science (article, 2022-01-01)
Field: Chemistry — Organic Chemistry

Anti-ageing and Anti-lung Carcinoma Effects of Vulpinic Acid and Usnic Acid Compounds and Biological Investigations with Molecular Modeling Study Disorganization and breakdown of extracellular matrix proteins like fibronectin, collagen, and elastin are key characteristics of skin aging due to the increased activation of important proteolytic enzymes like elastases and collagenase enzymes. Also, inhibition of their enzymatic activities by natural molecules might be a promising factor to prevent extrinsic skin aging. All chemicals were obtained from Sigma-Aldrich unless otherwise stated. The assay employed was based on spectrophotometric methods reported in the literature. The collagenase and elastase inhibition assays of some phenolic compounds were performed according to the previous studies. These compounds showed excellent to good inhibitory activities of vulpinic acid against studied these enzymes with IC50 values of 195.36 µM for collagenase and 25.24 µM for elastase. The molecular docking calculations were conducted to investigate the chemical and biological activity of vulpinic acid and usnic acid against collagenase and elastase. The results indicated that these two compounds can interact with the essential residues of the enzymes and affect their activities. The calculations of binding free energies were also performed to obtain more details about the characteristics and free energies of the ligand-enzyme complexes. Additionally, both compounds exhibited the most potent inhibition in the three lung cancer cells, with an IC50 value of 21-68 µM, indicating that vulpinic acid is more potent than Doxorubicin, which exhibited an IC50 value of 21-29 µM. Collagenase ; Chemistry ; Enzyme ; Biochemistry ; Elastase ; Elastin ; IC50 ; Usnic acid ; Tyrosinase ; Stereochemistry ; In vitro ; Biology Plant-Derived Bioactive Compounds ; Microbial Natural Products and Biosynthesis ; Biological Activity of Diterpenoids and Biflavonoids
Authors: Eric W. Deutsch | Juan Antonio Vizcaíno | Andrew R. Jones | Pierre‐Alain Binz | Henry Lam | Joshua Klein | Wout Bittremieux | Yasset Pérez‐Riverol | David L. Tabb | Mathias Walzer | Sylvie Ricard‐Blum | Henning Hermjakob | Steffen Neumann | Tytus D. Mak | Shin Kawano | Luis Mendoza | Tim Van Den Bossche | Ralf Gabriels | Nuno Bandeira | Jeremy Carver | Benjamin Pullman | Zhi Sun | Nils Hoffmann | Jim Shofstahl | Yunping Zhu | Luana Licata | Federica Quaglia | Silvio C. E. Tosatto | Sandra Orchard
Source: ChemRxiv (preprint, 2022-10-17)
Field: Chemistry — Spectroscopy

The Proteomics Standards Initiative at Twenty Years: Current Activities and Future Work The Human Proteome Organization (HUPO) Proteomics Standards Initiative (PSI) has been successfully developing guidelines, data formats, and controlled vocabularies (CVs) for the proteomics community and other fields supported by mass spectrometry since its inception twenty years ago. Here we describe the general operation of the PSI, including its leadership, working groups, yearly workshops, and the document process by which proposals are thoroughly and publicly reviewed in order to be ratified as PSI standards. We briefly describe the current state of the many existing PSI standards, some of which remain the same as when originally developed, some of which have undergone subsequent revisions, and some of which have become obsolete. Then the set of proposals currently being developed are described, with an open call to the community for participation in the forging of the next generation of standards. Finally, we describe some synergies and collaborations with other organizations and look to the future in how the PSI will continue to promote the open sharing of data and thus accelerate the progress of the field of proteomics. Work (physics) ; Political science ; Human proteome project ; Process (computing) ; Data science ; Engineering ; Computer science ; Proteomics ; Biology Advanced Proteomics Techniques and Applications ; Metabolomics and Mass Spectrometry Studies ; Mass Spectrometry Techniques and Applications
Authors: Haisang Liu | Yordan Kyosev | Gaoming Jiang
Source: Communications in development and assembling of textile products (article, 2022-09-03)
Field: Materials Science — Polymers and Plastics

Yarn level simulation of warp-knitted clothing elements – first results and challenges To simulate a warp-knitted product with a specific shape, a mesh-based model for modeling and simulation is proposed. The three-dimensional geometry of the final fabric is represented as a set of polygons, each of them containing information about the 3D orientation of the yarns in the warp knitted structure. Using spatial mapping, stitch coordinates are transformed from the flat mesh model to the three-dimensional mesh model and the final rendering is accomplished. The method provides yarn level data for the complete structure and can be used for speeding up the design process of clothing with warp-knitted products. Several challenges with the larger data amount and possible ways for their solutions are discussed. Yarn ; Rendering (computer graphics) ; Clothing ; Computer science ; Process (computing) ; Set (abstract data type) ; Engineering drawing ; Orientation (vector space) ; Computer graphics (images) ; Geometry ; Engineering ; Mechanical engineering ; Mathematics Textile materials and evaluations ; 3D Shape Modeling and Analysis ; Additive Manufacturing and 3D Printing Technologies
Authors: Mika Sarvilahti | Lasse Laurson
Source: Physical Review Materials (article, 2022-12-06)
Field: Materials Science — Materials Chemistry

Bayesian optimization of discrete dislocation plasticity of two-dimensional precipitation-hardened crystals Discovering relationships between materials' microstructures and mechanical properties is a key goal of materials science. Here, we outline a strategy exploiting Bayesian optimization to efficiently search the multidimensional space of microstructures, defined here by the size distribution of precipitates (fixed impurities or inclusions acting as obstacles for dislocation motion) within a simple two-dimensional discrete dislocation dynamics model. The aim is to design a microstructure optimizing a given mechanical property, e.g., maximizing the expected value of shear stress for a given strain. The problem of finding the optimal discretized shape for a distribution involves a norm constraint, and we find that sampling the space of possible solutions should be done in a specific way in order to avoid convergence problems. To this end, we propose a general mathematical approach that can be used to generate trial solutions uniformly at random while enforcing an Euclidean norm constraint. Both equality and inequality constraints are considered. A simple technique can then be used to convert between Euclidean and other Lebesgue $p$-norm (the 1-norm in particular) constrained representations. Considering different dislocation-precipitate interaction potentials, we demonstrate the convergence of the algorithm to the optimal solution and discuss its possible extensions to the more complex and realistic case of three-dimensional dislocation systems where also the optimization of precipitate shapes could be considered. Norm (philosophy) ; Dislocation ; Materials science ; Mathematical optimization ; Eigenstrain ; Applied mathematics ; Mathematics Microstructure and mechanical properties ; High Temperature Alloys and Creep ; Machine Learning in Materials Science
Authors: Marvin Stephan | Birgit Stute | Eric von Lieres | Thomas J. J. Müller
Source: European Journal of Organic Chemistry (article, 2022-03-31)
Field: Materials Science — Materials Chemistry

Consecutive Three‐Component Synthesis of Phenothiazine‐Based Merocyanines – Bayesian Optimization, Electronic properties, and DSSC Characteristics** Abstract A consecutive three‐component Heck‐Knoevenagel synthesis of phenothiazinyl merocyanines was developed by statistical design of experiments (DoE) and Bayesian optimization furnishing nine red orange dyes starting from heteroaryl halides, acrolein and ethyl cyanoacetate. Besides scrutinizing the electronic properties of these merocyanines by cyclic voltammetry, absorption and emission spectroscopy, and (TD)DFT calculations their saponified carboxylic acids were employed in dye‐sensitized solar cell (DSSC) experiments showing promising solar cell performances with relative efficiencies of up to 93 % compared to the standard ruthenium dye N3 . Chemistry ; Dye-sensitized solar cell ; Ruthenium ; Photochemistry ; Combinatorial chemistry ; Organic chemistry ; Physical chemistry ; Electrode ; Electrolyte Photochromic and Fluorescence Chemistry ; Quantum Dots Synthesis And Properties ; TiO2 Photocatalysis and Solar Cells