jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Rituparna Das | Arundhati Pal | Amal Paul
Source: Journal of Applied Biology & Biotechnology (article, 2019-03-01)
Field: Materials Science — Biomaterials

Bioconversion of sugarcane molasses to poly(3-hydroxybutyrate-co-3- hydroxyvalerate) by endophytic Bacillus cereus RCL 02 Sugarcane molasses, the by-product of sugar industry are rich in nutrients, growth factors and minerals and are efficiently utilized by the microorganisms for growth and production of primary as well as secondary metabolites of commercial importance. In this communication, we report the utilization of sugarcane molasses as the sole source of carbon for the production of copolymers of polyhydroxyalkanoates (PHAs) with improved material properties. The endophytic bacterium Bacillus cereus RCL 02 (MCC 3436) produced 7.8 g/L of PHA when grown in MS medium with 4% (w/v) sugarcane molasses under batch cultivation. Proton nuclear magnetic resonance ( 1 H NMR) analysis revealed that the copolymer so produced contain 12.4 mol% 3-hydroxyvalerate (3HV) along with 87.6 mol% 3-hydroxybutyrate (3HB). The copolyester, P(3HB-co-12.4 mol%-3HV) has been isolated and purified following standard solvent extraction method and partially characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric (TG) and differential scanning calorimetric (DSC) analysis. The material and thermal properties of the copolyester so produced indicated its potential for industrial application. Bioconversion ; Halophyte ; Bacillus cereus ; Botany ; Biology ; Food science ; Fermentation ; Bacteria ; Ecology ; Salinity biodegradable polymer synthesis and properties ; Enzyme Catalysis and Immobilization ; Biofuel production and bioconversion
Authors: Georgios Balokas | Benedikt Kriegesmann | Steffen Czichon | Raimund Rolfes
Source: Composites Part A Applied Science and Manufacturing (article, 2019-09-21)
Field: Materials Science — Polymers and Plastics

Stochastic modeling techniques for textile yarn distortion and waviness with 1D random fields Waviness ; Yarn ; Distortion (music) ; Stochastic process ; Random field ; Stochastic modelling ; Computer science ; Mathematics ; Mechanical engineering ; Engineering ; Statistics Textile materials and evaluations ; Mechanical Behavior of Composites ; Probabilistic and Robust Engineering Design
Authors: Cyntia M. Palacio | H.J. Rozeboom | Elisa Lanfranchi | Qinglong Meng | Marleen Otzen | Dick B. Janssen
Source: FEBS Journal (article, 2019-06-04)
Field: Materials Science — Biomaterials

Biochemical properties of a <i>Pseudomonas</i> aminotransferase involved in caprolactam metabolism The biodegradation of the nylon-6 precursor caprolactam by a strain of Pseudomonas jessenii proceeds via ATP-dependent hydrolytic ring opening to 6-aminohexanoate. This non-natural ω-amino acid is converted to 6-oxohexanoic acid by an aminotransferase (PjAT) belonging to the fold type I pyridoxal 5'-phosphate (PLP) enzymes. To understand the structural basis of 6-aminohexanoatate conversion, we solved different crystal structures and determined the substrate scope with a range of aliphatic and aromatic amines. Comparison with the homologous aminotransferases from Chromobacterium violaceum (CvAT) and Vibrio fluvialis (VfAT) showed that the PjAT enzyme has the lowest K<sub>M</sub> values (highest affinity) and highest specificity constant (k<sub>cat</sub> /K<sub>M</sub> ) with the caprolactam degradation intermediates 6-aminohexanoate and 6-oxohexanoic acid, in accordance with its proposed in vivo function. Five distinct three-dimensional structures of PjAT were solved by protein crystallography. The structure of the aldimine intermediate formed from 6-aminohexanoate and the PLP cofactor revealed the presence of a narrow hydrophobic substrate-binding tunnel leading to the cofactor and covered by a flexible arginine, which explains the high activity and selectivity of the PjAT with 6-aminohexanoate. The results suggest that the degradation pathway for caprolactam has recruited an aminotransferase that is well adapted to 6-aminohexanoate degradation. DATABASE: The atomic coordinates and structure factors P. jessenii 6-aminohexanoate aminotransferase have been deposited in the PDB as entries 6G4B (E∙succinate complex), 6G4C (E∙phosphate complex), 6G4D (E∙PLP complex), 6G4E (E∙PLP-6-aminohexanoate intermediate), and 6G4F (E∙PMP complex). Cofactor ; Chemistry ; Stereochemistry ; Pyridoxal phosphate ; Enzyme kinetics ; Pyridoxal ; Caprolactam ; Substrate (aquarium) ; Enzyme ; Hydrolysis ; Biochemistry ; Active site ; Organic chemistry ; Biology biodegradable polymer synthesis and properties ; Enzyme Structure and Function ; Biopolymer Synthesis and Applications
Authors: Gabriel Martínez‐Edo | Maria C. Llinàs | Salvador Borrós | David Sánchez‐García
Source: Nanomaterials (article, 2019-08-29)
Field: Materials Science — Materials Chemistry

Isothiocyanate-Functionalized Mesoporous Silica Nanoparticles as Building Blocks for the Design of Nanovehicles with Optimized Drug Release Profile A straightforward methodology for the synthesis of isothiocyanate-functionalized mesoporous silica nanoparticles (MSNs) by exposure of aminated MSNs to 1,1'-thiocarbonyldi-2(1<i>H</i>)-pyridone is reported. These nanoparticles are chemically stable, water tolerant, and readily react with primary amines without the formation of any by-product. This feature allows the easy modification of the surface of the nanoparticles for tuning their physical properties and the introduction of gatekeepers on the pore outlets. As a proof-of-concept, amino-isothiocyanate-functionalized MSNs have been used for the design of a nanocontainer able to release the drug Ataluren. The release profile of the drug can be easily fine-tuned with the careful choice of the capping amine. Mesoporous silica ; Nanoparticle ; Materials science ; Mesoporous material ; Nanotechnology ; Drug delivery ; Drug ; Isothiocyanate ; Mesoporous organosilica ; Microsphere ; Chemical engineering ; Chemistry ; Organic chemistry ; Pharmacology ; Engineering ; Catalysis Mesoporous Materials and Catalysis ; Nanoparticle-Based Drug Delivery ; Supramolecular Self-Assembly in Materials
Authors: Arnab Dawn | Xue Yao | Ying Yu | Jianxiong Jiang | Harshita Kumari
Source: Supramolecular chemistry (article, 2019-05-13)
Field: Chemistry — Organic Chemistry

Assessment of the <i>in vitro</i> toxicity of calixarenes and a metal-seamed calixarene: a chemical pathway for clinical application Calixarenes are known to form host-guest complexes and supramolecular nanoassemblies with well-defined architectures. However, the use of these materials in conjunction with drug moieties is still under explored. One reason is the insuffcient biocompatibility studies. Our present study represents a systematic <i>in vitro</i> investigation of the cytotoxicity associated with <i>C</i>-methylresorcin[4]arene, <i>C</i>-methylpyrogallol[4]arene, p-phosphonated calix[8]arene and a metal-seamed calixarene-copper(II) complex, using human HEK293 and rat C6G cell lines and two different cell viability assays (MTT and CellTiter-Glo) to avoid species-biased results. All compounds showed low to moderate toxicity. The trend in the CC<sub>50</sub> values indicated that the suppression of the coordination ability and the presence of phosphonate groups decrease the overall cytotoxicity of the compounds. The results of this study not only establish calixarenes and their immediate families as potential drug carriers and drug modifiers, but also reveal a pathway for fine-tuning their toxicological behaviour by appropriate chemical modification. Memphis ; Calixarene ; Chemistry ; Pharmacy ; Health science ; Pharmaceutical sciences ; Pharmacology ; Organic chemistry ; Medical education ; Medicine ; Family medicine ; Molecule Supramolecular Chemistry and Complexes ; Nanoparticle-Based Drug Delivery ; Chemical Synthesis and Analysis
Authors: Stella M. Luo | Kellie A. Stellmach | Stella Ikuzwe | Dennis Cao
Source: The Journal of Organic Chemistry (article, 2019-07-18)
Field: Materials Science — Materials Chemistry

Redox-Active Heteroacene Chromophores Derived from a Nonlinear Aromatic Diimide This work describes a three-step chromatography-free protocol for the synthesis of a novel organic materials building block, dichlorinated mellophanic diimide (MDI), that is shown to undergo nucleophilic substitution with a variety of <i>ortho</i> disubstituted benzenes to yield a series of chromophores. Furthermore, 1,2,4,5-tetrasubstituted benzenes can be used to synthesize tetraimide heteropentacene derivatives endcapped by MDI motifs. The fine-tuning effects of heteroatom identity were investigated by UV-vis and fluorescence spectroscopy, cyclic and differential pulse voltammetries, and density functional theory calculations. Oxidation of diamino MDI derivatives yields di- and tetraimide functionalized azaacenes with significantly lowered LUMO levels (down to -4.49 eV), narrowed band gaps (down to 1.81 eV), and high molar absorptivities (up to 84,000 M<sup>-1</sup> cm<sup>-1</sup>). Diimide ; Chromophore ; Chemistry ; HOMO/LUMO ; Photochemistry ; Redox ; Nucleophilic substitution ; Heteroatom ; Density functional theory ; Organic chemistry ; Computational chemistry ; Molecule Luminescence and Fluorescent Materials ; Nonlinear Optical Materials Research ; Organic Electronics and Photovoltaics
Authors: Erik Saparbaev | Vladimir Kopysov | Ruslan D. Yamaletdinov | Aleksandr Y. Pereverzev | Oleg V. Boyarkin
Source: Angewandte Chemie International Edition (article, 2019-03-29)
Field: Chemistry — Spectroscopy

Interplay of H‐Bonds with Aromatics in Isolated Complexes Identifies Isomeric Carbohydrates The tremendous isomeric diversity of carbohydrates enables a wide range of their biological functions but makes the identification and study of these molecules difficult. We investigated the ability of intermolecular interactions to communicate structural specificity of carbohydrates to protonated aromatic molecules in non-covalent complexes, isolated and cooled in the gas phase. Our study revealed that small structural differences between carbohydrate isomers of any type, including enantiomers, are accurately communicated by these interactions to aromatic molecules as detectable changes in their electronic excitation spectra. The specific response of the aromatics to the isomers of carbohydrates is fine-tuned by the interplay of the various involved non-covalent bonds. These findings enable the gas-phase identification and relative quantification of any isomers of oligosaccharides in their solution mixtures using the 2D UV-MS fingerprinting technique. Chemistry ; Molecule ; Covalent bond ; Protonation ; Intermolecular force ; Computational chemistry ; Stereochemistry ; Organic chemistry Analytical Chemistry and Chromatography ; Biochemical Analysis and Sensing Techniques ; Glycosylation and Glycoproteins Research
Authors: Aurelio García‐Valenzuela | Rafael Álvarez | J.P. Espinós | Víctor Rico | Jorge Gil‐Rostra | Alberto Palmero | Agustín R. González‐Elipe
Source: Applied Surface Science (article, 2019-05-24)
Field: Materials Science — Materials Chemistry

SiOx by magnetron sputtered revisited: Tailoring the photonic properties of multilayers Materials science ; Porous silicon ; Sputter deposition ; Nanostructure ; Photonics ; Deposition (geology) ; Silicon ; Etching (microfabrication) ; Refractive index ; Optoelectronics ; Porosity ; Thin film ; Sputtering ; Nanotechnology ; Optics ; Composite material ; Layer (electronics) Silicon Nanostructures and Photoluminescence ; Optical Coatings and Gratings ; Photonic Crystals and Applications
Authors: Ioannis K. Kouparitsas | Elisa Mele | Sara Ronca
Source: Polymers (article, 2019-04-13)
Field: Materials Science — Biomaterials

Synthesis and Electrospinning of Polycaprolactone from an Aluminium-Based Catalyst: Influence of the Ancillary Ligand and Initiators on Catalytic Efficiency and Fibre Structure In the present study, we investigated the catalytic performance of a 2,2′-methylenebis(6-tert-butyl-4-methylphenol) (MDBP)–aluminium complex for the ring-opening polymerisation (ROP) of ε-caprolactone in combination with various alcohols as initiators. Three different alcohols were investigated: 1-adamantanemethanol (A), 1H,1H,2H,2H-perfluoro-1-octanol (F) and isopropanol (I). Samplings of polycaprolactone (PCL) at various reaction times showed a linear increase in the polymer molecular weight with time, with very narrow polydispersity, confirming the living nature of the catalytic system. Scanning electron microscope (SEM) images of electrospun PCL fibre mats produced from 30 wt % dichloromethane/dimethyl sulfoxide solutions showed a high level of surface porosity with a reasonable homogeneity of fibre diameters. The values of the liquid absorption and water contact angle were measured for the electrospun mats, with the F-capped PCL consistently showing absorption values up to three times higher than those of PCL samples capped with the other two alcohols, as well as increased hydrophobicity. The nature of the alcohol can influence the surface hydrophobicity and absorption ability of electrospun fibres, demonstrating the possibility of tailoring material properties through controlled polymerisation. Polycaprolactone ; Electrospinning ; Catalysis ; Materials science ; Dispersity ; Chemical engineering ; Contact angle ; Scanning electron microscope ; Absorption of water ; Polymer ; Benzenesulfonic acid ; Lactide ; Polyester ; Polymerization ; Caprolactone ; Dichloromethane ; Polymer chemistry ; Porosity ; Composite material ; Chemistry ; Organic chemistry ; Solvent Electrospun Nanofibers in Biomedical Applications ; biodegradable polymer synthesis and properties ; Advanced Sensor and Energy Harvesting Materials
Authors: Linda K. Månsson | Tym de Wild | Feifei Peng | Stefan H. Holm | Jonas O. Tegenfeldt | Peter Schurtenberger
Source: Soft Matter (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Preparation of colloidal molecules with temperature-tunable interactions from oppositely charged microgel spheres The self-assembly of small colloidal clusters, so-called colloidal molecules, into crystalline materials has proven extremely challenging, the outcome often being glassy, amorphous states where positions and orientations are locked. In this paper, a new type of colloidal molecule is therefore prepared, assembled from poly(N-isopropylacrylamide) (PNIPAM)-based microgels that due to their well documented softness and temperature-response allow for greater defect tolerance compared to hard spheres and for convenient in situ tuning of size, volume fraction and inter-particle interactions with temperature. The microgels (B) are assembled by electrostatic adsorption onto oppositely charged, smaller-sized microgels (A), where the relative size of the two determines the valency (n) of the resulting core-satellite ABn-type colloidal molecules. Following assembly, a microfluidic deterministic lateral displacement (DLD) device is used to effectively isolate AB4-type colloidal molecules of tetrahedral geometry that possess a repulsive-to-attractive transition on crossing the microgels' volume phase transition temperature (VPTT). These soft, temperature-responsive colloidal molecules constitute highly promising building blocks for the preparation of new materials with emergent properties, and their optical wavelength-size makes them especially interesting for optical applications. Colloid ; Molecule ; SPHERES ; Chemical physics ; Particle (ecology) ; Materials science ; Nanotechnology ; Colloidal particle ; Core (optical fiber) ; Volume fraction ; Particle size ; Soft matter ; Chemical engineering ; Chemistry ; Physics ; Physical chemistry ; Organic chemistry ; Composite material Pickering emulsions and particle stabilization ; Surfactants and Colloidal Systems ; Polymer Surface Interaction Studies
Authors: Bhupendra Goswami | Ravi Yadav | Christoph Schoo | Peter W. Roesky
Source: Dalton Transactions (article, 2019-12-17)
Field: Chemistry — Organic Chemistry

Neutral and cationic enantiopure group 13 iminophosphonamide complexes Synthesis and reactivity of enantiopure iminophosphonamide ligand L-H (L = [Ph2P{N(R)CH(CH3)Ph}2]) with group 13 metal compounds has been investigated. The reaction of L-H with LiAlH4 afforded the aluminium monohydride complex [L2AlH]. The monochloride complexes [L2MCl] (M = Al, Ga) were accessed by reacting corresponding MCl3 (M = Al, Ga) with L-Li. Furthermore, the tetracoordinated aluminium cation [L2Al]+[GaCl4]- and gallium cation [L2Ga]+[AlCl4]- were obtained by chloride abstraction from [L2MCl] (M = Al, Ga), respectively. The title complexes represent the first examples of enantiopure group 13 metal complexes coordinated by chiral iminophosphonamides. All complexes have been characterized by single crystal X-ray diffraction, multinuclear NMR, EA and IR studies. Enantiopure drug ; Cationic polymerization ; Group (periodic table) ; Halide ; Chemistry ; Abstraction ; Ligand (biochemistry) ; Metal ; Stereochemistry ; Medicinal chemistry ; Polymer chemistry ; Organic chemistry ; Enantioselective synthesis ; Catalysis ; Biochemistry ; Philosophy Organophosphorus compounds synthesis ; Asymmetric Hydrogenation and Catalysis ; Chemical Synthesis and Characterization
Authors: Henrik Flötotto | Tim Secker | Paul Kögerler | Claire Besson
Source: European Journal of Inorganic Chemistry (article, 2019-09-04)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Amine‐Functionalized Spin Crossover Building Blocks Bistable spin crossover complexes such as [Fe{HB(pz) 3 } 2 ] (pzH = pyrazole) show promise for sensor applications and electrically‐controlled data storage units, but exploiting their potential hinges on their integration into a functional environment. We here present a system enabling such covalent post‐functionalization steps in both symmetric and asymmetric patterns, based on the amine‐functionalized complex [Fe{HB(4‐NH 2 pz)(pz) 2 } 2 ], obtained by reduction of the nitro analogue. The building block aspects of [Fe{HB(4‐NH 2 pz)(pz) 2 } 2 ] are showcased by its transformation into amide, imine and azo derivatives, which are structurally and magnetically characterized. All tris(pyrazolyl)borate complexes retain the spin crossover properties of their parent compound, with spin crossover temperatures ranging from 350 to 430 K. The transition parameters are correlated with the electronic properties of the functionalizing group, opening the possibility of fine‐tuning the spin crossover properties of the building block as it is integrated in the environment of choice. Spin crossover ; Chemistry ; Imine ; Amine gas treating ; Covalent bond ; Bistability ; Amide ; Crossover ; Block (permutation group theory) ; Combinatorial chemistry ; Crystallography ; Chemical physics ; Organic chemistry ; Optoelectronics ; Materials science Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: H. H. Wensink
Source: Crystals (article, 2019-03-10)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Effect of Size Polydispersity on the Pitch of Nanorod Cholesterics Many nanoparticle-based chiral liquid crystals are composed of polydisperse rod-shaped particles with considerable spread in size or shape, affecting the mesoscale chiral properties in, as yet, unknown ways. Using an algebraic interpretation of Onsager-Straley theory for twisted nematics, we investigate the role of length polydispersity on the pitch of nanorod-based cholesterics with a continuous length polydispersity, and find that polydispersity enhances the twist elastic modulus, K 2 , of the cholesteric material without affecting the effective helical amplitude, K t . In addition, for the infinitely large average aspect ratios considered here, the dependence of the pitch on the overall rod concentration is completely unaffected by polydispersity. For a given concentration, the increase in twist elastic modulus (and reduction of the helical twist) may be up to 50% for strong size polydispersity, irrespective of the shape of the unimodal length distribution. We also demonstrate that the twist reduction is reinforced in bimodal distributions, obtained by doping a polydisperse cholesteric with very long rods. Finally, we identify a subtle, non-monotonic change of the pitch across the isotropic-cholesteric biphasic region. Dispersity ; Materials science ; Twist ; Isotropy ; Rod ; Nanorod ; Elastic modulus ; Optics ; Condensed matter physics ; Composite material ; Nanotechnology ; Physics ; Polymer chemistry ; Geometry ; Mathematics Liquid Crystal Research Advancements ; Surfactants and Colloidal Systems ; Lipid Membrane Structure and Behavior
Authors: Eleutheria Papazoi | Antigoni Douvali | Stavros A. Diamantis | Giannis S. Papaefstathiou | Svetlana V. Eliseeva | Stéphane Pètoud | Antonios G. Hatzidimitriou | Theodore Lazarides | Manolis J. Manos
Source: Molecular Systems Design & Engineering (article, 2019-10-01)
Field: Chemistry — Inorganic Chemistry

Unravelling the mechanism of water sensing by the Mg<sup>2+</sup> dihydroxy-terephthalate MOF (<b>AEMOF-</b>1′) The amorphous compound [Mg(H<sub>2</sub>dhtp)(H<sub>2</sub>O)<sub>2</sub>] <bold>1′</bold> was shown to be a highly efficient and reusable luminescent sensor for the detection of water in THF, due to its transformation to the strongly emissive complex [Mg(H<sub>2</sub>dhtp)(H<sub>2</sub>O)<sub>5</sub>]·H<sub>2</sub>O <bold>1</bold>. Amorphous solid ; Luminescence ; Chemistry ; Crystallography ; Materials science ; Analytical Chemistry (journal) ; Optoelectronics ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Inorganic Fluorides and Related Compounds ; Molecular Sensors and Ion Detection
Authors: Yera Ussembayev | Zeger Hens | Kristiaan Neyts
Source: ACS Photonics (article, 2019-01-29)
Field: Materials Science — Materials Chemistry

Contrasting Anisotropy of Light Absorption and Emission by Semiconductor Nanoparticles Photon absorption and emission play a key role in our understanding of how light interacts with matter. An attractive system to explore these processes are semiconductor nanoparticles (SNP) with their distinguishable photoluminescence, which makes them widely applied in optoelectronics, laser technology, and biophotonics. In current implementations of SNP, there is only partial control over anisotropy in absorption or in emission, which limits their applicability in photonics. An emerging strategy to attain a certain degree of anisotropy is to embed a quantum dot in semiconductor shell structure. Here, we report how designing the shell geometry and the position of the quantum dot enables extended control over the anisotropy in absorption and emission by a core/shell nanoparticle in a solvent. Based on the dielectric effect, our approach provides an accessible route to achieve sharply contrasting anisotropies that may even have an opposite sign. Using this unique feature, we propose cross particles to transform unpolarized blue light into polarized red and green light for liquid crystal backlights and thumbtack particles to absorb sunlight and efficiently emit photons in a solar concentrator. The strong anisotropic contrast between absorption and emission of SNP may advance energy-efficient technology, biodiagnostics, and quantum information, as well as offer new insights on light–matter interaction at the nanoscale. Quantum dot ; Absorption (acoustics) ; Photonics ; Semiconductor ; Materials science ; Anisotropy ; Optoelectronics ; Photon ; Photoluminescence ; Biophotonics ; Photonic crystal ; Optics ; Physics Quantum Dots Synthesis And Properties ; Gold and Silver Nanoparticles Synthesis and Applications ; Chalcogenide Semiconductor Thin Films