jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sergey O. Ilyin | Viktoria Y. Melekhina | Anna V. Kostyuk | Н. М. Смирнова
Source: Polymers (article, 2022-10-13)
Field: Chemistry — Analytical Chemistry

Hot-Melt and Pressure-Sensitive Adhesives Based on Styrene-Isoprene-Styrene Triblock Copolymer, Asphaltene/Resin Blend and Naphthenic Oil Asphaltene/resin blend (ARB) extracted from heavy crude oil was used to modify poly(styrene-block-isoprene-block-styrene) (SIS) to make it an adhesive. There were prepared double and triple mixtures containing 10–60% SIS, 10–40% ARB, and 10–50% naphthenic oil used as an additional plasticizer. The viscoelasticity of the mixtures at 25 °C and 120 °C was studied, their flow curves were obtained, and the temperature dependences of the loss tangent and the components of the complex modulus were measured. In addition, the mixtures were used as hot-melt adhesives (HMAs) and pressure-sensitive adhesives (PSAs) in the shear, peel, and pull-off tests of the adhesive bonds that they formed with steel. Both naphthenic oil and ARB act as plasticizers for SIS and make it sticky. However, only the combined use of ARB and the oil allows for achieving the best set of adhesive properties of the SIS-based mixture. High-quality HMA requires low oil content (optimal SIS/ARB/oil ratio is 50/40/10, pull-off adhesion strength (τt) of 1990 kPa), whereas a lot of the oil is needed to give SIS characteristics of a PSA (SIS/ARB/oil is 20/40/40, τt of 100 kPa). At the same time, the resulting PSA can be used as a hot-melt pressure-sensitive adhesive (HMPSA) that has many times lower viscosity than HMA (13.9 Pa·s versus 2640 Pa·s at 120 °C and 1 s−1) but provides a less strong adhesive bond (τt of 960 kPa). Copolymer ; Styrene ; Isoprene ; Materials science ; Adhesive ; Asphaltene ; Chemical engineering ; Organic chemistry ; Composite material ; Chemistry ; Polymer Petroleum Processing and Analysis ; Analytical Chemistry and Chromatography ; Polymer composites and self-healing
Authors: Yongju Hong | Sandhya Venkateshalu | Sangyeon Jeong | Jong‐Sik Park | Kwangyeol Lee
Source: Small Science (article, 2022-12-03)
Field: Materials Science — Materials Chemistry

Regiospecific Cation Exchange in Nanocrystals and Its Potential in Diversifying the Nanostructural Library The cation-exchange reaction (CER), a promising nanocrystal (NC) engineering strategy, has undergone rapid progress in the past decade, sparking a big wave of interest in the post-synthetic tuning of chemical compositions, crystal phases, interfaces, morphologies, and corresponding properties. However, a significant gap has existed between the theoretical and actual CERs, hindering the popularization of CERs for explosive expansion in NC designs. A notable roadblock in this area has been the inability to control the site of cation exchange within the nanostructure, although partial cation exchange at desired sites can open an avenue to the vast structural diversity of nanostructures and accompany new physicochemical properties. Several notable successes have been recorded recently in fabricating predesigned hetero-nanostructures by thoroughly understanding the principles of cation exchange and by exploiting the peculiarity of each crystal system. Herein, recent advances achieved in the CER are introduced, unraveling the critical factors controlling regiospecificity by analyzing the developed theories and accumulated experimental results. It is further described how this knowledge can be harnessed to design advanced NCs, and the beneficial effect of regiospecificity on material properties is highlighted. Finally, the challenges and research directions are provided to encourage further research in this burgeoning field. Nanocrystal ; Nanotechnology ; Nanostructure ; Materials science Quantum Dots Synthesis And Properties ; Copper-based nanomaterials and applications ; Nanocluster Synthesis and Applications
Authors: Sangho Koh | Michio Sato | Kota Yamashina | Yuki Usukura | Masanori Toyofuku | Nobuhiko Nomura | Seiichi Taguchi
Source: Scientific Reports (article, 2022-03-01)
Field: Materials Science — Biomaterials

Controllable secretion of multilayer vesicles driven by microbial polymer accumulation Membrane vesicles (MVs) are formed in various microorganisms triggered by physiological and environmental phenomena. In this study, we have discovered that the biogenesis of MV took place in the recombinant cell of Escherichia coli BW25113 strain that intracellularly accumulates microbial polyester, polyhydroxybutyrate (PHB). This discovery was achieved as a trigger of foam formation during the microbial PHB fermentation. The purified MVs were existed as a mixture of outer MVs and outer/inner MVs, revealed by transmission electron microscopy. It should be noted that there was a good correlation between MV formation and PHB production level that can be finely controlled by varying glucose concentrations, suggesting the causal relationship in both supramolecules artificially produced in the microbial platform. Notably, the controllable secretion of MV was governed spatiotemporally through the morphological change of the E. coli cells caused by the PHB intracellular accumulation. Based on a hypothesis of PHB internal-pressure dependent envelope-disorder induced MV biogenesis, here we propose a new Polymer Intracellular Accumulation-triggered system for MV Production (designated "PIA-MVP") with presenting a mechanistic model for MV biogenesis. The PIA-MVP is a promising microbial platform that will provides us with a significance for further study focusing on biopolymer capsulation and cross-membrane transportation for different application purposes. Biogenesis ; Polyhydroxybutyrate ; Intracellular ; Secretion ; Biophysics ; Escherichia coli ; Chemistry ; Biopolymer ; Membrane ; Cell envelope ; Cell biology ; Vesicle ; Bacterial outer membrane ; Bacteria ; Biochemistry ; Polymer ; Biology ; Gene biodegradable polymer synthesis and properties ; Polymer Surface Interaction Studies ; Advanced Sensor and Energy Harvesting Materials
Authors: Sérgio R. S. Veloso | Raquel G. D. Andrade | Valéria Gomes | Carlos O. Amorim | V. S. Amaral | Verónica Salgueiriño | Paulo J. G. Coutinho | Paula M. T. Ferreira | Miguel A. Correa‐Duarte | Elisabete M. S. Castanheira
Source: International Journal of Molecular Sciences (article, 2022-11-16)
Field: Materials Science — Materials Chemistry

Oxidative Precipitation Synthesis of Calcium-Doped Manganese Ferrite Nanoparticles for Magnetic Hyperthermia Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (Ca<i><sub>x</sub></i>Mn<sub>1-<i>x</i></sub>Fe<sub>2</sub>O<sub>4</sub>) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy. Nanoparticle ; Materials science ; Superparamagnetism ; Magnetic nanoparticles ; Magnetic hyperthermia ; Magnetization ; Hyperthermia therapy ; Chemical engineering ; Aqueous solution ; Manganese ; Raman spectroscopy ; Precipitation ; Nanotechnology ; Chemistry ; Metallurgy ; Magnetic field ; Organic chemistry Magnetic Properties and Synthesis of Ferrites ; Iron oxide chemistry and applications ; Characterization and Applications of Magnetic Nanoparticles
Authors: Paulina Kalle | Marina A. Kiseleva | Sergei V. Tatarin | Daniil E. Smirnov | Alexander Y. Zakharov | В. В. Емец | Andrei V. Churakov | Stanislav I. Bezzubov
Source: Molecules (article, 2022-05-17)
Field: Chemistry — Organic Chemistry

A Panchromatic Cyclometalated Iridium Dye Based on 2-Thienyl-Perimidine Though 2-arylperimidines have never been used in iridium(III) chemistry, the present study on structural, electronic and optical properties of <i>N</i>-unsubstituted and <i>N</i>-methylated 2-(2-thienyl)perimidines, supported by DFT/TDDFT calculations, has shown that these ligands are promising candidates for construction of light-harvesting iridium(III) complexes. In contrast to <i>N</i>-H perimidine, the <i>N</i>-methylated ligand gave the expected cyclometalated μ-chloro-bridged iridium(III) dimer which was readily converted to a cationic heteroleptic complex with 4,4'-dicarboxy-2,2'-bipyridine. The resulting iridium(III) dye exhibited panchromatic absorption up to 1000 nm and was tested in a dye-sensitized solar cell. Iridium ; Chemistry ; Time-dependent density functional theory ; Panchromatic film ; Cationic polymerization ; Photochemistry ; Dimer ; Ligand (biochemistry) ; Molecule ; Polymer chemistry ; Organic chemistry ; Catalysis ; Physics Synthesis and Biological Evaluation ; Radical Photochemical Reactions ; Organic Light-Emitting Diodes Research
Authors: Roland Pfoh | Adithya S. Subramanian | Jingjing Huang | Dustin J. Little | Adam Forman | Benjamin R. DiFrancesco | Negar Balouchestani-Asli | Elena N. Kitova | John S. Klassen | Régis Pomès | Mark Nitz | P. Lynne Howell
Source: PLoS Pathogens (article, 2022-08-05)
Field: Materials Science — Materials Chemistry

The TPR domain of PgaA is a multifunctional scaffold that binds PNAG and modulates PgaB-dependent polymer processing The synthesis of exopolysaccharides as biofilm matrix components by pathogens is a crucial factor for chronic infections and antibiotic resistance. Many periplasmic proteins involved in polymer processing and secretion in Gram-negative synthase dependent exopolysaccharide biosynthetic systems have been individually characterized. The operons responsible for the production of PNAG, alginate, cellulose and the Pel polysaccharide each contain a gene that encodes an outer membrane associated tetratricopeptide repeat (TPR) domain containing protein. While the TPR domain has been shown to bind other periplasmic proteins, the functional consequences of these interactions for the polymer remain poorly understood. Herein, we show that the C-terminal TPR region of PgaA interacts with the de-N-acetylase domain of PgaB, and increases its deacetylase activity. Additionally, we found that when the two proteins form a complex, the glycoside hydrolase activity of PgaB is also increased. To better understand structure-function relationships we determined the crystal structure of a stable TPR module, which has a conserved groove formed by three repeat motifs. Tryptophan quenching, mass spectrometry analysis and molecular dynamics simulation studies suggest that the crystallized TPR module can bind PNAG/dPNAG via its electronegative groove on the concave surface, and potentially guide the polymer through the periplasm towards the porin for export. Our results suggest a scaffolding role for the TPR domain that combines PNAG/dPNAG translocation with the modulation of its chemical structure by PgaB. Periplasmic space ; Tetratricopeptide ; Sortase ; Porin ; Biochemistry ; Protein structure ; Protein domain ; Biophysics ; Chemistry ; Bacterial outer membrane ; Biology ; Cell biology ; Gene ; Escherichia coli Enzyme Structure and Function ; Bacterial biofilms and quorum sensing ; Enzyme Production and Characterization
Authors: Margherita Bini | Giorgia Brancolini | Valentina Tozzini
Source: Frontiers in Molecular Biosciences (review, 2022-09-19)
Field: Chemistry — Organic Chemistry

Aggregation behavior of nanoparticles: Revisiting the phase diagram of colloids Surface functionalization of metal nanoparticles (NPs), e.g., using peptides and proteins, has recently attracted a considerable attention in the field of design of therapeutics and diagnostics. The possibility of diverse functionalization allows them to selectively interact with proteins, while the metal core ensures solubility, making them tunable therapeutic agents against diseases due to mis-folding or aggregation. On the other hand, their action is limited by possible self-aggregation, which could be, however, prevented based on the full understanding of their phase diagram as a function of the environmental variables (temperature, ionic strength of the solution, concentration) and intrinsic characteristics (size, charge, amount, and type of functional groups). A common modeling strategy to study the phase behavior is to represent the NPs as spheres interacting via effective potentials implicitly accounting for the solvation effects. Their size put the NPs into the class of colloids, albeit with particularly complex interactions including both attractive and repulsive features, and a consequently complex phase diagram. In this work, we review the studies exploring the phases of these systems starting from those with only attractive or repulsive interactions, displaying a simpler disperse-clustered-aggregated transitions. The phase diagram is here interpreted focusing on the universal aspects, i.e., those dependent on the general feature of the potentials, and available data are organized in a parametric phase diagram. We then consider the potentials with competing attractive short range well and average-long-range repulsive tail, better representing the NPs. Through the proper combination of the attractive only and repulsive only potentials, we are able to interpret the appearance of novel phases, characterized by aggregates with different structural characteristics. We identify the essential parameters that stabilize the disperse phase potentially useful to optimize NP therapeutic activity and indicate how to tune the phase behavior by changing environmental conditions or the NP chemical-physical properties. Phase diagram ; Chemical physics ; Nanoparticle ; Solvation ; Phase (matter) ; Nanotechnology ; Colloid ; Chemistry ; Statistical physics ; Materials science ; Physics ; Molecule ; Physical chemistry Surfactants and Colloidal Systems ; Proteins in Food Systems ; Pickering emulsions and particle stabilization
Authors: Frederic Krätschmer | Xiaofei Sun | Sebastian Gillhuber | Hannes Kucher | Yannick J. Franzke | Florian Weigend | Peter W. Roesky
Source: Chemistry - A European Journal (article, 2022-12-19)
Field: Chemistry — Organic Chemistry

Fully Tin‐Coated Coinage Metal Ions: A Pincer‐Type Bis‐stannylene Ligand for Exclusive Tetrahedral Complexation The synthesis of a novel bis-stannylene pincer ligand and its complexation with coinage metals (Cu<sup>I</sup> , Ag<sup>I</sup> and Au<sup>I</sup> ) are described. All coinage metal centres are in tetrahedral coordination environments in the solid state and are exclusively coordinated by four neutral Sn<sup>II</sup> donors. <sup>119</sup> Sn NMR provided information about the behaviour in solution. All of the isolated compounds have photoluminescent properties, and these were investigated at low and elevated temperatures. Compared to the free bis-stannylene ligand, coordination to coinage metals led to an increase in the luminescence intensity. The new compounds were investigated in detail through all-electron relativistic density functional theory (DFT) calculations. Pincer movement ; Ligand (biochemistry) ; Tin ; Metal ; Crystallography ; Chemistry ; Tetrahedron ; Luminescence ; Tetrahedral molecular geometry ; Density functional theory ; Photoluminescence ; Ion ; Metal ions in aqueous solution ; Photochemistry ; Inorganic chemistry ; Materials science ; Computational chemistry ; Crystal structure ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Synthesis and characterization of novel inorganic/organometallic compounds ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
Authors: Samih Haj Ibrahim | Tomasz Wejrzanowski | Bartłomiej Przybyszewski | Rafał Kozera | Xabier García‐Casas | Ángel Barranco
Source: Materials (article, 2022-04-25)
Field: Materials Science — Surfaces, Coatings and Films

Role of Surface Topography in the Superhydrophobic Effect—Experimental and Numerical Studies Within these studies, the effect of surface topography for hydrophobic coatings was studied both numerically and experimentally. Chemically modified polyurethane coating was patterned by application of a laser beam. A set of patterns with variously distant linear peaks and grooves was obtained. The cross section of the pattern showed that the edges of the peaks and grooves were not sharp, instead forming a rounded, rectangle-like shape. For such surfaces, experimental studies were performed, and in particular the static contact angle (SCA), contact angle hysteresis (CAH), and roll-off angle (ROA) were measured. Profilometry was used to create a numerical representation of the surface. Finite volume method was then applied to simulate the behavior of the water droplets. The model developed herewith enabled us to reproduce the experimental results with good accuracy. Based on the verified model, the calculation was extended to study the behavior of the water droplet on the simulated patterns, both spiked and rectangular. These two cases, despite a similar SCA of the water droplet, have shown extremely different ROA. Thus, more detailed studies were dedicated to other geometrical features of such topography, such as the size and distance of the surface elements. Based on the results obtained herewith, the future design of superhydrophobic and/or icephobic topography is discussed. Contact angle ; Materials science ; Rectangle ; Hysteresis ; Surface (topology) ; Optics ; Composite material ; Geometry ; Physics ; Mathematics Surface Modification and Superhydrophobicity ; Fluid Dynamics and Heat Transfer ; Icing and De-icing Technologies
Authors: Ruggero Emmanuele | Michał Maciejczyk | Ashton Smith | Xinyue Cheng | Eric Masson | David J. Gosztola | Saw‐Wai Hla | Neil Robertson | Xuedan Ma
Source: ACS Photonics (article, 2022-04-26)
Field: Materials Science — Materials Chemistry

Microcavity-Modified Emission from Rare-Earth Ion-Based Molecular Complexes Despite the remarkable optical properties of rare-earth ion materials, their applications as light sources and in quantum technologies are often hindered by their long lifetimes and weak emission. Leveraging the natural compatibility of rare-earth ion molecular complexes with photonic structures, here we modify their photoluminescence properties by coupling them to a flexible open Fabry–Pérot cavity. The full in situ tunability of the Fabry–Pérot cavity allows fine control over its cavity modes and the achievement of resonant coupling between the rare-earth ion emission and the cavity modes. This configuration allows us to achieve a maximum photoluminescence enhancement factor of 30 and accelerate the decay rate up to two orders of magnitude. Our pump-power-dependent spectroscopic studies of the emitter–cavity system suggest that the cavity-modified emission is primarily caused by amplified spontaneous emission. These results suggest that integrating rare-earth ion molecular complexes with photonic structures could be a viable approach for the effective tuning of their optical properties. This natural compatibility, together with their versatile molecular structures and the resultant electronic states, renders rare-earth ion molecular complexes a potential alternative material platform for lighting and quantum applications. Photoluminescence ; Materials science ; Ion ; Spontaneous emission ; Photonics ; Optoelectronics ; Light emission ; Common emitter ; Chemical physics ; Optics ; Laser ; Chemistry ; Physics Lanthanide and Transition Metal Complexes ; Luminescence and Fluorescent Materials ; Strong Light-Matter Interactions
Authors: И. В. Рыжов | Alexey V. Eroshin | Yuriy A. Zhabanov | Daniil N. Finogenov | Pavel A. Stuzhin
Source: International Journal of Molecular Sciences (article, 2022-05-11)
Field: Materials Science — Materials Chemistry

DFT Study of Molecular Structure, Electronic and Vibrational Spectra of Tetrapyrazinoporphyrazine, Its Perchlorinated Derivative and Their Al, Ga and In Complexes Electronic and geometric structures of metal-free, Al, Ga and In complexes with tetrapyrazinoporphyrazine (TPyzPA) and octachlorotetrapyrazinoporphyrazine (TPyzPACl<sub>8</sub>) were investigated by density functional theory (DFT) calculations and compared in order to study the effect of chlorination on the structure and properties of these macrocycles. The nature of the bonds between metal atoms and nitrogen atoms was described using the NBO-analysis. Simulation and interpretation of electronic spectra were performed with the use of time-dependent density functional theory (TDDFT). A description of calculated IR spectra was carried out based on the analysis of the distribution of the potential energy of normal vibrational coordinates. Time-dependent density functional theory ; Natural bond orbital ; Density functional theory ; Computational chemistry ; Electronic structure ; Chemistry ; Spectral line ; Metal ; Derivative (finance) ; Molecular physics ; Physical chemistry ; Physics ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Metal complexes synthesis and properties ; Nonlinear Optical Materials Research
Authors: Shaoqiu Ke | Di Xie | Kai Zhang | Fangchao Cheng | Yiqiang Wu
Source: Materials Advances (article, 2022-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Ultraflexible all-in-one supercapacitors with high capacitance and ultrastable cycle performance enabled by wood cellulose network An aligned all-in-one architecture based on a wood cellulose network endowed the ultra-flexible all-solid-state supercapacitors with elevalated electronic/ionic conductivity, high capacitance and ultrastable cycle performance. Supercapacitor ; Capacitance ; Cellulose ; Materials science ; Process engineering ; Composite material ; Electrode ; Chemical engineering ; Engineering ; Chemistry Supercapacitor Materials and Fabrication ; Conducting polymers and applications ; Advanced Sensor and Energy Harvesting Materials