jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Aleksandra Tobolska | Nina E. Wezynfeld | Urszula E. Wawrzyniak | Wojciech Bal | Wojciech Wróblewski
Source:  (article, 2021-06-30)
Field: Chemistry — Spectroscopy

Metal–Peptide Complexes—A Novel Class of Molecular Receptors for Electrochemical Phosphate Sensing Determination of phosphate anions concentration in body fluids provides information about various disorders such as hyperparathyroidism or vitamin D deficiency. Therefore, the monitoring of phosphates level is of interest for human health. Chemical sensors are a good alternative to classic analytical methods, but their construction requires the synthesis of appropriate receptors selectively binding the analyte. Amyloid β peptides (Aβ) related to Alzheimer’s Disease are well known for their neurotoxic properties. However, their N-terminally truncated analogs own unique coordination properties that could be employed in the design of potential receptors for biorelevant anionic species. The Aβ5-9 peptide possesses a His-2 binding motif and thus forms stable complexes with transition metal ions, where metal ion such as Cu(II) or Ni(II) is bound by three nitrogen (3N) from the His residue, the N-terminal amine, and the peptide backbone amide. The resulting chelates exhibit high stability and a labile coordination site enabling ternary interactions. Furthermore, metal-peptide complexes offer the possibility of fine-tuning their sensitivity and selectivity for desired applications by altering the amino acid sequence and metal ion center. The present work explores and compares the coordination and redox properties of Aβ5-9 complexes with Cu(II) and Ni(II) ions using electrochemical and spectroscopic techniques. The ability of binding biologically relevant phosphate anions and nucleotides by metal-peptide complexes was also studied. Obtained results provided a new insight into the design of a promising class of peptide-based molecular receptors with potential application as recognition elements in electrochemical biosensors and in vitro clinical diagnostics. Acknowledgments: This work has been financially supported by the Warsaw University of Technology under the program Excellence Initiative, Research University (ID-UB), BIOTECHMED-1 project no. PSP 504/04496/1020/45.010407 and implemented as a part of the Operational Program Knowledge Education Development 2014-2020 (Project No POWR.03.02.00-00-I007/16-00) co-financed by the European Social Fund. Chemistry ; Peptide ; Combinatorial chemistry ; Electrochemistry ; Amide ; Metal ; Metal ions in aqueous solution ; Inorganic chemistry ; Stereochemistry ; Biochemistry ; Organic chemistry Molecular Sensors and Ion Detection ; Advanced biosensing and bioanalysis techniques ; Electrochemical sensors and biosensors
Authors: Eri Yoshida
Source: Colloid and Surface Science (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Giant Vesicles of Amphiphilic Diblock Copolymer with Branched Side Chains Biomolecules of lipids and proteins optimize the hydrophobicity to precisely form their three-dimensional structures. The branching of hydrocarbon chains is appropriate for fine-tuning the hydrophobicity of the molecules because it provides a slight reduction in hydrophobicity. This paper describes the morphological changes of vesicles formed by an amphiphilic diblock copolymer supporting branched side chains in the hydrophobic block to elucidate the steric effect of the side chains on the morphology. The vesicles consisting of poly(methacrylic acid)-<i>block</i>-poly(isopropyl methacrylate-<i>random</i>-methacrylic acid), PMAA-<i>b</i>-P(iPMA-<i>r</i>-MAA), were obtained by the polymerization-induced self-assembly using the photo-nitroxide mediated controlled/living radical polymerization (photo-NMP) in an aqueous methanol solution (methanol/water=3/1 <i>v</i>/<i>v</i>). PMAA-<i>b</i>-P(iPMA-<i>r</i>-MAA) with a very high ratio of the iPMA units produced spherical vesicles. As the iPMA ratio decreased, the vesicles shrank, expanded again, and changed into sheets. The chain length of the hydrophobic block also dominated the morphology. For the high iPMA ratio constant, the copolymers with a short block produced two domains of micron-sized spherical vesicles and unspecific nano-sized particles fused. An increase in the block length changed the nanoparticles into nanospheres, accompanied by an increase in the number of micron-sized spherical vesicles. By further extending the block length, most of the nanospheres grew into micron-sized spherical vesicles. On the other hand, for the low iPMA ratio constant, an increase in the length of the hydrophobic chain changed the unspecific nanoparticles sheets into aggregates with an inverted hexagonal phase reticularly perforated. The PMAA-<i>b</i>-P(<i>n</i>-propyl methacrylate-<i>r</i>-MAA) copolymer produced flexible sheets with a smooth surface without any pores, while PMAA-<i>b</i>-P(methyl methacrylate-<i>r</i>-MAA) provided rods of laminated sheets. It was found that the formation of the inverted hexagonal phase was due to the steric repulsion of the bulky isopropyl groups in the hydrophobic blocks. These findings indicate that the morphology of the vesicles is manipulated not only by the hydrophobicity of the copolymer, but also by the bulkiness of the branched side chain in the hydrophobic block. Vesicle ; Copolymer ; Amphiphile ; Polymer chemistry ; Polymersome ; Methacrylic acid ; Polymerization ; Chemistry ; Side chain ; Micelle ; Materials science ; Chemical engineering ; Aqueous solution ; Organic chemistry ; Polymer ; Membrane Advanced Polymer Synthesis and Characterization ; Supramolecular Self-Assembly in Materials ; Polymer Surface Interaction Studies
Authors: Nayon Park | Forrest W. Eagle | Asher DeLarme | Madison Monahan | Talia LoCurto | Ryan Beck | Xiaosong Li | Brandi M. Cossairt
Source: ChemRxiv (preprint, 2021-08-04)
Field: Materials Science — Materials Chemistry

Tuning the Interfacial Stoichiometry of InP Core and InP/ZnSe Core/Shell Quantum Dots We demonstrate fine-tuning of the atomic composition of InP/ZnSe QDs at the core/shell interface. Specifically, we control the stoichiometry of both anions (P, As, S, and Se) and cations (In, Zn) at the InP/ZnSe core/shell interface and correlate these changes with the resultant steady-state and time-resolved optical properties of the nanocrystals. The use of reactive trimethylsilyl reagents results in surface-limited reactions that shift the nanocrystal stoichiometry to anion-rich and improve epitaxial growth of the shell layer. In general, anion deposition on the InP QD surface results in a redshift in the absorption, quenching of the excitonic photoluminescence, and a relative increase in the intensity of the broad trap-based photoluminescence, consistent with delocalization of the exciton wavefunction and relaxation of exciton confinement. Time-resolved photoluminescence data for the resulting InP/ZnSe QDs show an overall small change in the decay dynamics on the ns timescale, suggesting the relatively low photoluminescence quantum yields may be attributed to the creation of new thermally activated charge trap states and likely a dark population that is inseparable from the emissive QDs. Cluster-model density functional theory calculations show that the presence of core/shell interface anions give rise to electronic defects contributing to the redshift in the absorption. These results highlight a general strategy to atomistically tune the interfacial stoichiometry of InP QDs using surface-limited reaction chemistry allowing for precise correlations with electronic structure and photophysical processes. Photoluminescence ; Quantum dot ; Stoichiometry ; Exciton ; Delocalized electron ; Materials science ; Absorption (acoustics) ; Chemical physics ; Nanocrystal ; Nucleation ; Molecular physics ; Chemistry ; Nanotechnology ; Optoelectronics ; Condensed matter physics ; Physical chemistry ; Physics Quantum Dots Synthesis And Properties ; Semiconductor Quantum Structures and Devices ; Chalcogenide Semiconductor Thin Films
Authors: Ching-min Yeh | T. H. Jarrett | Yuan Gao | Chunxia Zhao | Andrew K. Whittaker | Frank Sainsbury | Alison White
Source: ChemRxiv (preprint, 2021-03-24)
Field: Materials Science — Biomaterials

Templating Core-Shell Particles Using Metal Ion-Chelating Biosurfactants Designer biosurfactants can be used to stabilise and functionalise interfaces. One particularly promising use is the stabilisation of oil-in-water emulsions, enabling fine tuning physical, chemical and biological surface properties. The ability of emulsion systems to carry high payloads makes them attractive for applications in medicine, food and fragrances, and cosmetics. However, they have limited long-term stability. Here we sought to use the metal ion-chelating ability of the biosurfactant peptide, AM1, to precipitate the formation of a gold metal shell on AM1-stabilised emulsions by electroless plating. We found that replacing the commonly used zinc(II) with palladium(II) for coordination by histidine residues of adjacent AM1 peptides produced interfacial films that maintained elasticity at acidic pH. Proton NMR suggested a coordination mechanism independent of the imidazole ring of the histidines. Nevertheless. stabilisation of emulsions at low pH enabled the deposition of a gold shell, albeit by an unexpected mechanism. We propose that gold nanoparticles forming in bulk are adsorbed onto the peptide-stabilised interface, accumulating into a particulate coating. The resulting one-step method for nanoparticle precipitation and shell formation will be useful for the creation of biocompatible core-shell particles for applications where large payloads of hydrophobic active compounds require stability over long time periods. Chelation ; Emulsion ; Metal ; Chemical engineering ; Nanoparticle ; Chemistry ; Imidazole ; Metal ions in aqueous solution ; Nanotechnology ; Adsorption ; Materials science ; Coating ; Colloidal gold ; Salt (chemistry) ; Organic chemistry Supramolecular Self-Assembly in Materials ; Polymer Surface Interaction Studies ; Corrosion Behavior and Inhibition
Authors: Charles Bryant | J. Payne | Calleigh Brannan | R. Marquez Tavera | Maitri Warusawithana
Source: University of North Florida Digital Commons (University of North Florida) (article, 2021-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Magnetic Properties of MBE Grown La1-xSrxMnO3 Thin Films versus Bulk Crystal Data We have studied how the ferromagnetic transition and other magnetic properties vary with concentration. Data collected has been analyzed, using SigmaPlot software, to better evaluate reduced dimensionality effects on the magnetic behavior of lanthanum strontium manganite (La1-xSrxMnO3 or LSMO). Measurements using reflection high-energy electron diffraction (RHEED) were incorporated to verify that the crystals are high quality. We then measured the magnetic properties using our Superconducting Quantum Interference Device (SQUID) magnetometer. These magnetic properties have been analyzed to determine the characteristics of the superlattice. The primary goal has involved the magnetic data collection and analysis. Our analysis has investigated the major ferromagnetic properties and other qualities of the samples. Critical temperature, saturated magnetic moment, remnant moment, and Bohr magneton versus temperature as well as the ferromagnetic to paramagnetic transition temperature have been studied in detail over a sample range of Sr concentration values from x = 0.04 to 0.20. This has provided a better insight into the interesting behavior exhibited at concentration x = 0.04, where the canted anti-ferromagnetic properties begin to become apparent in this doping range but aren’t apparent at higher doping (higher concentrations). Thanks to the research grant provided by The Office of Undergraduate Research we have the helium gas that is essential for producing the liquid helium needed for more measurements that will be required to fine tune and verify our data for scientific publication. Materials science ; Crystal (programming language) ; Condensed matter physics ; Thin film ; Crystallography ; Chemistry ; Physics ; Nanotechnology ; Computer science Magnetic and transport properties of perovskites and related materials ; Magnetic Properties of Alloys ; Rare-earth and actinide compounds
Source: Journal of Cranio-Maxillofacial Surgery (article, 2021-06-16)
Field: Materials Science — Materials Chemistry

EACMFS Awards Adenylyl cyclase ; Optogenetics ; Flavin group ; Second messenger system ; ADCY9 ; Biophysics ; ADCY10 ; ADCY6 ; Chemistry ; Biology ; Cell biology ; Signal transduction ; Biochemistry ; Enzyme ; Neuroscience Photochromic and Fluorescence Chemistry ; Algal biology and biofuel production
Authors: Nwigbo Solomon Chuka | Godwin Kingsley Obiazi | Ikebudu Kingsley Okechukwu
Source: Global Journal of Engineering and Technology Advances (article, 2021-07-17)
Field: Materials Science — Polymers and Plastics

Application of Taguchi Robust Design for optimizing tensile strength response of Ukam-plant fibre reinforced cashew nut shell liquid (CNSL) composite by the effects of control parameters This paper focuses on the application of Taguchi Robust Design to determine the optimum tensile strength of Ukam-Plant Fibre Reinforced CNSL Composite using indigenous or locally sourced vegetable or plant based natural fibres (Ukam-plant fibres) that are Lignocellulose as potential raw material. Tensile tests were conducted on the replicated samples of Ukam-Plant Fibre Reinforced CNSL Composite to obtain the optimum properties. Hounsfield Mosanto Tensometer, a universal testing machine was used to conduct tensile tests to determine the control factor levels quality characteristics considered necessary to optimize the mechanical property being investigated. Methodology of traditional and experimental design approach of Taguchi was used for the larger the better to obtain the highest signal to noise ratio (SN ratio) for the quality characteristic being investigated and also to correlate the control factors (fibre condition i.e. untreated, silane treated and alkaline treated, volume fraction and fibre size). Minitab 16 software was used for statistical analysis to fine-tune conclusions and produce quantitative estimates. The optimum settings were as follows: alkaline treatment, volume fraction of 50%, and 50mm of fibre size which resulted in 18.69MPa optimum tensile strength. The experimental results obtained agreed satisfactorily with the Minitab 16 software predictions. The mechanical property studied revealed that composite depends significantly on the reinforcement combination of control parameters. Taguchi methods ; Ultimate tensile strength ; Materials science ; Composite material ; Composite number ; Orthogonal array ; Reinforcement Natural Fiber Reinforced Composites ; Agricultural Engineering and Mechanization ; Mechanical Engineering and Vibrations Research
Authors: Nwigbo Solomon Chuka | Godwin Kingsley Obiazi | Ikebudu Kingsley Okechukwu
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2021-07-30)
Field: Materials Science — Polymers and Plastics

Application of Taguchi Robust Design for optimizing tensile strength response of Ukam-plant fibre reinforced cashew nut shell liquid (CNSL) composite by the effects of control parameters This paper focuses on the application of Taguchi Robust Design to determine the optimum tensile strength of Ukam-Plant Fibre Reinforced CNSL Composite using indigenous or locally sourced vegetable or plant based natural fibres (Ukam-plant fibres) that are Lignocellulose as potential raw material. Tensile tests were conducted on the replicated samples of Ukam-Plant Fibre Reinforced CNSL Composite to obtain the optimum properties. Hounsfield Mosanto Tensometer, a universal testing machine was used to conduct tensile tests to determine the control factor levels quality characteristics considered necessary to optimize the mechanical property being investigated. Methodology of traditional and experimental design approach of Taguchi was used for the larger the better to obtain the highest signal to noise ratio (SN ratio) for the quality characteristic being investigated and also to correlate the control factors (fibre condition i.e. untreated, silane treated and alkaline treated, volume fraction and fibre size). Minitab 16 software was used for statistical analysis to fine-tune conclusions and produce quantitative estimates. The optimum settings were as follows: alkaline treatment, volume fraction of 50%, and 50mm of fibre size which resulted in 18.69MPa optimum tensile strength. The experimental results obtained agreed satisfactorily with the Minitab 16 software predictions. The mechanical property studied revealed that composite depends significantly on the reinforcement combination of control parameters. Cashew nut ; Composite number ; Ultimate tensile strength ; Taguchi methods ; Shell (structure) ; Nut ; Composite material ; Materials science ; Structural engineering ; Engineering ; Chemistry Natural Fiber Reinforced Composites
Authors: Ching-min Yeh | T. H. Jarrett | Yuan Gao | Chunxia Zhao | Andrew K. Whittaker | Frank Sainsbury | Alison White
Source: ChemRxiv (preprint, 2021-03-24)
Field: Materials Science — Biomaterials

Templating Core-Shell Particles Using Metal Ion-Chelating Biosurfactants &lt;p&gt;Designer biosurfactants can be used to stabilise and functionalise interfaces. One particularly promising use is the stabilisation of oil-in-water emulsions, enabling fine tuning physical, chemical and biological surface properties. The ability of emulsion systems to carry high payloads makes them attractive for applications in medicine, food and fragrances, and cosmetics. However, they have limited long-term stability. Here we sought to use the metal ion-chelating ability of the biosurfactant peptide, AM1, to precipitate the formation of a gold metal shell on AM1-stabilised emulsions by electroless plating. We found that replacing the commonly used zinc(II) with palladium(II) for coordination by histidine residues of adjacent AM1 peptides produced interfacial films that maintained elasticity at acidic pH. Proton NMR suggested a coordination mechanism independent of the imidazole ring of the histidines. Nevertheless. stabilisation of emulsions at low pH enabled the deposition of a gold shell, albeit by an unexpected mechanism. We propose that gold nanoparticles forming in bulk are adsorbed onto the peptide-stabilised interface, accumulating into a particulate coating. The resulting one-step method for nanoparticle precipitation and shell formation will be useful for the creation of biocompatible core-shell particles for applications where large payloads of hydrophobic active compounds require stability over long time periods.&lt;/p&gt; Chelation ; Emulsion ; Metal ; Chemistry ; Chemical engineering ; Nanoparticle ; Imidazole ; Metal ions in aqueous solution ; Adsorption ; Nanotechnology ; Salt (chemistry) ; Materials science ; Combinatorial chemistry ; Organic chemistry Supramolecular Self-Assembly in Materials
Authors: Daniel Bím | Anastassia N. Alexandrova
Source: ChemRxiv (preprint, 2021-04-21)
Field: Chemistry — Electrochemistry

Electrostatic Regulation of Blue Copper Sites &lt;div&gt; &lt;p&gt;In the last 50 years, the blue copper proteins became central targets of investigation. Extensive experiments focused on the first- and second-coordination spheres of Cu to probe the effect of local perturbations on its properties. We found that local electric fields, generated by charged residues evolutionarily placed throughout the protein edifice, constitute an additional significant factor regulating blue copper proteins. These fields are not random, but exhibit a highly specific directionality, negative with respect to Cu-S&lt;sub&gt;Cys&lt;/sub&gt; and Cu-S&lt;sub&gt;Met&lt;/sub&gt; in the Cu first shell. The field magnitude contributes to fine-tuning of the geometric and electronic properties of Cu sites in individual blue copper proteins. Specifically, the local electric fields evidently control the Cu-S&lt;sub&gt;Met&lt;/sub&gt; bond distance, Cu(II)-S&lt;sub&gt;Cys&lt;/sub&gt; bond covalency, and the energies of the frontier molecular orbitals, which, in turn, govern the Cu(II/I) reduction potential and the relative absorption intensities at 450 nm and 600 nm.&lt;/p&gt; &lt;/div&gt; &lt;br&gt; Copper ; Electric field ; Crystallography ; Chemistry ; Atomic orbital ; Absorption (acoustics) ; SPHERES ; Bond length ; Copper protein ; Physics ; Electron ; Crystal structure ; Optics Electrochemical Analysis and Applications ; Trace Elements in Health ; Protein Structure and Dynamics
Authors: Michael K. Trubetskov
Source:  (article, 2021-09-09)
Field: Materials Science — Materials Chemistry

Efficient multilayer coating design with elements of machine learning Modern design tools allow solving a wide set of the most challenging multilayer design problems, but they require a deep knowledge of synthesis methods, and good expertise in applying various design tricks to obtain a good solution. During the last two decades computational performance of modern computers allows one to consider more computationally demanding approaches, including those ones based on deep search methods. Deep search approaches require enumeration of all possibilities on each iteration of a method. The number of different possibilities (layer insertion locations for the needle optimization, layer boundaries for the gradual evolution iteration, layer number for the design cleaner, etc.) is growing with the complexity of the coating. Therefore, the computational time of any deep search method considering all possibilities is also growing dramatically. To mitigate this challenge, we propose to use self-adapting algorithms accumulating information on main computational metrics (the numbers of required iterations, the evolution of merit functions versus iteration, the behavior of the merit function gradient norm). Accumulated information can be efficiently used to complete the computations of promising variants and to interrupt iterations of unfavorable variants very early. Proposed self-adapting and self-learning method serves as a superstructure upon well-known multilayer optimization methods, such as needle optimization, gradual evolution, design cleaner, etc. A huge advantage of the new self-learning method is that it does not require any careful fine tuning during computations. New method can run in completely automatic mode and nevertheless provide high quality solutions of challenging design problems. Computer science ; Computation ; Deep learning ; Set (abstract data type) ; Mathematical optimization ; Computer engineering ; Theoretical computer science ; Artificial intelligence ; Algorithm ; Mathematics Machine Learning in Materials Science ; Optical Coatings and Gratings ; Chemical and Physical Properties of Materials