Search results for "Functionalization"
showing 10 items of 137 documents
Duplicated cytoglobin genes in teleost fishes
2005
Cytoglobin is a recently discovered myoglobin-related O2-binding protein of vertebrates with uncertain function. It occurs as single-copy gene in mammals. Here, we demonstrate the presence of two paralogous cytoglobin genes (Cygb-1 and Cygb-2) in the teleost fishes Danio rerio, Oryzias latipes, Tetraodon nigroviridis, and Takifugu rubripes. The globin-typical introns at positions B12.2 and G7.0 are conserved in both genes, whereas the C-terminal exon found in mammalian cytoglobin is absent in the fish genes. Phylogenetic analyses show that the two cytoglobin genes diverged early in teleost evolution. This is confirmed by gene synteny analyses, which suggest a large-scale duplication event. …
An Atom-Economical Approach to Functionalized Single-Walled Carbon Nanotubes: Reaction with Disulfides
2013
Owing to their unique structure, thermal stability, and mechanical and electronic properties, single-walled carbon nanotubes (SWCNTs) have been a subject of continuous and intense interest. However, various applications in many fields, such as molecular electronics, solar cells, and nanomedicine, often require the development of reproducible protocols for the chemical modification of SWCNTs. In fact, one of the main drawbacks of the use of SWCNTs is their tendency to aggregate and intrinsic poor solubility, which prevent their manipulation and limit their potential. To date, several methods have been described for the chemical functionalization of SWCNTs; however, new versatile and reliable…
Magnaporthe oryzae as an expression host for the production of the unspecific peroxygenase AaeUPO from the basidiomycete Agrocybe aegerita.
2021
Abstract The filamentous fungus Magnaporthe oryzae has the potential to be developed as an alternative platform organism for the heterologous production of industrially important enzymes. M. oryzae is easy to handle, fast‐growing and unlike yeast, posttranslational modifications like N‐glycosylations are similar to the human organism. Here, we established M. oryzae as a host for the expression of the unspecific peroxygenase from the basidiomycete Agrocybe aegerita (AaeUPO). Note, UPOs are attractive biocatalysts for selective oxyfunctionalization of non‐activated carbon‐hydrogen bonds. To improve and simplify the isolation of AaeUPO in M. oryzae, we fused a Magnaporthe signal peptide for pr…
Palladium-catalyzed heteroaryl thioethers synthesis overcoming palladium dithiolate resting states inertness: Practical road to sulfones and NH-sulfo…
2018
International audience; We provide efficient synthetic access to heteroaryl sulfones in two-steps using a simple palladium-1,1'-bis [(diphenyl)phosphanyl]ferrocene catalyst to form in high yields variously functionalized heteroaromatic thioethers. Pyridinyl-containing substrates can be subsequently selectively oxidized into sulfones and NH-sulfoximines by using very mild oxidation conditions with a high functional group tolerance. In the palladium catalyzed C-S coupling of heteroaromatic thiols, reactivity limitation is attached with electron-deficient thiols. We show that this limitation can be resolved by the successful use of 2-bromoheteroarenes in the C-S coupling. We established herein…
Electrochemical C−H Functionalization of (Hetero)Arenes—Optimized by DoE
2020
Abstract A novel approach towards the activation of different arenes and purines including caffeine and theophylline is presented. The simple, safe and scalable electrochemical synthesis of 1,1,1,3,3,3‐hexafluoroisopropanol (HFIP) aryl ethers was conducted using an easy electrolysis setup with boron‐doped diamond (BDD) electrodes. Good yields up to 59 % were achieved. Triethylamine was used as a base as it forms a highly conductive media with HFIP, making additional supporting electrolytes superfluous. The synthesis was optimized using Design of Experiment (DoE) techniques giving a detailed insight to the significance of the reaction parameters. The mechanism was investigated by cyclic volt…
Reversible self-assembly of metal chalcogenide/metal oxide nanostructures based on Pearson hardness.
2010
Nanotechnology has reached a stage of development where not individual nanoparticles but rather systems of greater complexity are the focus of concern. These complex structures incorporate two or more types of materials, an example of which is the formation of metal–semiconductor hybrids, which effectively combine the properties of both materials. The assembly of multicomponent nanoparticles from constituents with different optical, electrical, magnetic, and chemical properties can lead to novel functionalities that are independent of the individual components and may be tailored to fit a specific application. These applications include such far-reaching challenges as solar energy conversio…
Fabrication of Single Cylindrical Au-Coated Nanopores with Non-Homogeneous Fixed Charge Distribution Exhibiting High Current Rectifications
2014
We have designed and characterized a cylindrical nanopore that exhibits high electrochemical current rectification ratios at low and intermediate electrolyte concentrations. For this purpose, the track-etched single cylindrical nanopore in polymer membrane is coated with a gold (Au) layer via electroless plating technique. Then, a non-homogeneous fixed charge distribution inside the Au-coated nanopore is obtained by incorporating thiol-terminated uncharged poly(N-isopropylacrylamide) (PNIPAM) chains in series to poly(4-vinyl pyridine) (PVP) chains, which are positively charged at acidic pH values. The functionalization reaction is checked by measuring the current–voltage (I–V) curves prior …
Conformation of Polyethylene Glycol inside Confined Space: Simulation and Experimental Approaches
2021
The modification of the inner nanopore wall by polymers is currently used to change the specific properties of the nanosystem. Among them, the polyethylene glycol (PEG) is the most used to prevent the fouling and ensure the wettability. However, its properties depend mainly on the chain structure that is very difficult to estimate inside this confined space. Combining experimental and simulation approaches, we provide an insight to the consequence of the PEG presence inside the nanopore on the nanopore properties. We show, in particular, that the cation type in the electrolyte, together with the type of electrolyte (water or urea), is at the origin of the ion transport modification in the n…
Enhancing the mechanical performance of polymer based nanocomposites by plasma-modification of nanoparticles
2012
Abstract The possibility of enhancing the mechanical performance of two different polymer-based nanocomposites using polyamide 6 (PA6) and poly[ethylene-co-(vinyl acetate)] (EVA) as matrices was investigated. The nanofillers used were, respectively, either carbon nanotubes (CNTs) or an organically modified montmorillonite (Cloisite 15A), both previously modified by plasma treatment to introduce polar moieties. The nanofillers were fully characterized by Raman spectroscopy, XPS, FT-IR and XRD, demonstrating their effective modification with oxygenated groups. The nanocomposites were prepared by melt processing in order to obtain films and fibres. The mechanical tests carried out on the nanoc…
Functionalization of aliphatic polyesters by nitroxide radical coupling
2014
Functionalized poly(butylene succinate) (PBS) samples were prepared by a post-polymerization method based on the coupling reaction between TEMPO derivatives bearing different functionalities and PBS macroradicals generated by H-abstraction using a peroxide. 4-Benzoyloxy-2,2,6,6-tetramethylpiperidine-1- oxyl (BzO-TEMPO) and 4-(1-naphthoate)-2,2,6,6-tetramethylpiperidine-1-oxyl (NfO-TEMPO), a pro-fluorescent nitroxide, were successfully grafted on PBS, as revealed by MALDI TOF MS and UV-Vis spectroscopy. The functionalization degrees were accurately determined by UV-Vis analysis and confirmed by 1H-NMR spectroscopy. The grafting site was identified by combining theoretical calculations with e…