Search results for "lcsh:Organic chemistry"
showing 10 items of 438 documents
Microfluidic Synthesis of Actuating Microparticles from a Thiol-Ene Based Main-Chain Liquid Crystalline Elastomer.
2016
In this article the microfluidic synthesis of strongly actuating particles on the basis of a liquid crystalline main-chain elastomer is presented. The synthesis is carried out in a capillary-based co-flow microreactor by photo-initiated thiol-ene click chemistry of a liquid crystalline monomer mixture. These microparticles exhibit a deformation from a spherical to a rod-like shape during the thermal-initiated phase transition of the liquid crystalline elastomer (LCE) at which the particles’ aspect ratio is almost doubled. Repeated contraction cycles confirm the complete reversibility of the particles’ actuation properties. The transition temperature of the LCE, the temperature range of the …
Semiflexible Polymers Interacting with Planar Surfaces: Weak versus Strong Adsorption
2020
Semiflexible polymers bound to planar substrates by a short-range surface potential are studied by Molecular Dynamics simulations to clarify the extent to which these chain molecules can be considered as strictly two-dimensional. Applying a coarse-grained bead-spring model, the chain length N and stiffness &kappa
Dephosphorylation of Centrins by Protein Phosphatase 2C α and β.
2009
In the present study, we identified protein phosphatases dephosphorylating centrins previously phosphorylated by protein kinase CK2. The following phosphatases known to be present in the retina were tested: PP1, PP2A, PP2B, PP2C, PP5, and alkaline phosphatase. PP2C 𝛼 and 𝛽 were capable of dephosphorylating P-Thr138-centrin1 most efficiently. PP2C𝛿 was inactive and the other retinal phosphatases also had much less or no effect. Similar results were observed for centrins 2 and 4. Centrin3 was not a substrate for CK2. The results suggest PP2C 𝛼 and 𝛽 to play a significant role in regulating the phosphorylation status of centrins in vivo.
Activity and Thermal Stability of Cobalt(II)-Based Olefin Polymerization Catalysts Adorned with Sterically Hindered Dibenzocycloheptyl Groups.
2019
Five examples of unsymmetrical 2-(2,4-bis(dibenzocycloheptyl)-6-methylphenyl- imino)ethyl)-6-(1-(arylyimino)ethyl)pyridine derivatives (aryl = 2,6-Me2C6H3 in L1
Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response
2018
Carbon dots (CDs) are an emerging family of nanosystems displaying a range of fascinating properties. Broadly speaking, they can be described as small, surface-functionalized carbonaceous nanoparticles characterized by an intense and tunable fluorescence, a marked sensitivity to the environment and a range of interesting photochemical properties. CDs are currently the subject of very intense research, motivated by their possible applications in many fields, including bioimaging, solar energy harvesting, nanosensing, light-emitting devices and photocatalyis. This review covers the latest advancements in the field of CDs, with a focus on the fundamental understanding of their key photophysica…
Effect of Halogen Ions on the Photocycle of Fluorescent Carbon Nanodots
2019
Carbon dots (C-dots) are well-known for their strong sensitivity to the environment, which reflects on intensity and shape changes of their fluorescence, induced by various interacting ions and molecules in solution. Although these interactions have been extensively studied in the last few years, especially in view of their possible sensing applications, the existing works have mostly focused on the quenching of C-dot fluorescence induced by metal cations. In fact, these latter easily bind to C-dots surfaces, which are negatively charged in most cases, promoting an electron transfer from the surface to them. Much less is known from the literature on the effect induced on C-dots by prototypi…
Chemical Composition Analysis, Antimicrobial Activity and Cytotoxicity Screening of Moss Extracts (Moss Phytochemistry)
2015
Mosses have been neglected as a study subject for a long time. Recent research shows that mosses contain remarkable and unique substances with high biological activity. The aim of this study, accordingly, was to analyze the composition of mosses and to screen their antimicrobial and anticancer activity. The total concentration of polyphenols and carbohydrates, the amount of dry residue and the radical scavenging activity were determined for a preliminary evaluation of the chemical composition of moss extracts. In order to analyze and identify the substances present in mosses, two types of extrahents (chloroform, ethanol) and the GC/MS and LC-TOF-MS methods were used. The antimicrobial activ…
Phytotoxic Activities of Mediterranean Essential Oils
2010
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Durability of Basalt/Hemp Hybrid Thermoplastic Composites
2019
The Achilles heel of thermoplastic natural fibre composites is their limited durability. The environmental degradation of the mechanical properties of hemp and hemp/basalt hybrid-reinforced high-density polyethylene (HDPE) composites has been investigated with a special focus on the effects of water ageing and accelerated ageing, including hygrothermal and UV radiation. Modification of the matrix was carried out using a maleic anhydride high-density polyethylene copolymer (MAPE) as a compatibilizer. Hybridization of hemp fibres with basalt fibres and the incorporation of MAPE were found to significantly decrease the water uptake (up to 75%) and increase the retention of mechanical propertie…
Multi-Alkenylsilsesquioxanes as Comonomers and Active Species Modifiers of Metallocene Catalyst in Copolymerization with Ethylene.
2018
The copolymers of ethylene (E) with open-caged iso-butyl-substituted tri-alkenyl-silsesquioxanes (POSS-6-3 and POSS-10-3) and phenyl-substituted tetra-alkenyl-silsesquioxane (POSS-10-4) were synthesized by copolymerization over the ansa-metallocene catalyst. The influence of the kind of silsesquioxane and of the copolymerization conditions on the reaction performance and on the properties of the copolymers was studied. In the case of copolymerization of E/POSS-6-3, the positive comonomer effect was observed, which was associated with the influence of POSS-6-3 on transformation of the bimetallic ion pair to the active catalytic species. Functionality of silsesquioxanes and polymerization par…