Search results for "interactions."
showing 10 items of 1865 documents
Structure and thermal properties of a chitosan coated polyethylene bilayer film
2012
The thermal and the structural properties of chitosan coated polyethylene (PE) films were studied. The coating process did not significantly influence the thermal stability and the PE surface structure and/or composition of the polyolefin. Dehydration temperature of chitosan films reflected the strength of water/acetic acid/chitosan chains interactions. Glycerol, used as a plasticizer, formed new hydrophilic centres in the film matrix. Moreover it was better integrated in the CSEGLY than in CSAGLY network. Besides, the addition of a plasticizer in the chitosan films decreased the film degradation temperature. There were two main steps for the PE chitosan coated films degradation. The first …
HPMA-based block copolymers promote differential drug delivery kinetics for hydrophobic and amphiphilic molecules.
2015
Abstract We describe a method how polymeric nanoparticles stabilized with (2-hydroxypropyl)methacrylamide (HPMA)-based block copolymers are used as drug delivery systems for a fast release of hydrophobic and a controlled release of an amphiphilic molecule. The versatile method of the miniemulsion solvent-evaporation technique was used to prepare polystyrene (PS) as well as poly-d/l-lactide (PDLLA) nanoparticles. Covalently bound or physically adsorbed fluorescent dyes labeled the particles’ core and their block copolymer corona. Confocal laser scanning microscopy (CLSM) in combination with flow cytometry measurements were applied to demonstrate the burst release of a fluorescent hydrophobic…
Organic Polyradicals as Redox Mediators: Effect of Intramolecular Radical Interactions on Their Efficiency
2020
The spin–spin interactions between unpaired electrons in organic (poly)radicals, especially nitroxides, are largely investigated and are of crucial importance for their applications in areas such as organic magnetism, molecular charge transfer, or multiple spin labeling in structural biology. Recently, 2,2,6,6-tetramethylpiperidinyloxyl and polymers functionalized with nitroxides have been described as successful redox mediators in several electrochemical applications; however, the study of spin–spin interaction effect in such an area is absent. This communication reports the preparation of a novel family of discrete polynitroxide molecules, with the same number of radical units but differe…
Influence of Substrate Hydrophilicity on Structural Properties of Supported Lipid Systems on Graphene, Graphene Oxides, and Silica
2021
Pristine graphene, a range of graphene oxides, and silica substrates were used to investigate the effect of surface hydrophilicity on supported lipid bilayers by means of all-atom molecular dynamics simulations. Supported 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers were found in close-contact conformations with hydrophilic substrates with as low as 5% oxidation level, while self-assembled monolayers occur on pure hydrophobic graphene only. Lipids and water at the surface undergo large redistribution to maintain the stability of the supported bilayers. Deposition of bicelles on increasingly hydrophilic substrates shows the continuous process of reshaping of the supported system a…
Electron-phonon heat transport and electronic thermal conductivity in heavily doped silicon-on-insulator film
2003
Electron–phonon interaction and electronic thermal conductivity have been investigated in heavily doped silicon at subKelvin temperatures. The heat flow between electron and phonon systems is found to be proportional to T6. Utilization of a superconductor–semiconductor–superconductor thermometer enables a precise measurement of electron and substrate temperatures. The electronic thermal conductivity is consistent with the Wiedemann–Franz law. Peer reviewed
Stacking as a key property for creating nanoparticles with tunable shape: The case of squalenoyl-doxorubicin
2019
The development of elongated nanoparticles for drug delivery is of growing interest in recent years, due to longer blood circulation and improved efficacy compared to spherical counterparts. Squalenoyl-doxorubicin (SQ-Dox) conjugate was previously shown to form elongated nanoparticles with improved therapeutic efficacy and decreased toxicity compared to free doxorubicin. By using experimental and computational techniques, we demonstrate here that the specific physical properties of SQ-Dox, which include stacking and electrostatic interactions of doxorubicin as well as hydrophobic interactions of squalene, are involved in the formation of nanoassemblies with diverse elongated structures. We …
Self-Assembly of Amphiphilic Nanocrystals
2009
Amphiphilic hybrid materials are formed from polymer-coated semiconductor nanoparticles that simulate a surfactant-like response (see picture). The strength and density of the surface coating are the key assembling forces driving a transition from single particles to cylindrical or vesicular superstructures.
Biomaterial Surface Hydrophobicity-Mediated Serum Protein Adsorption and Immune Responses.
2019
The nature of the protein corona forming on biomaterial surfaces can affect the performance of implanted devices. This study investigated the role of surface chemistry and wettability on human serum-derived protein corona formation on biomaterial surfaces and the subsequent effects on the cellular innate immune response. Plasma polymerization, a substrate-independent technique, was employed to create nanothin coatings with four specific chemical functionalities and a spectrum of surface charges and wettability. The amount and type of protein adsorbed was strongly influenced by surface chemistry and wettability but did not show any dependence on surface charge. An enhanced adsorption of the …
Influence of the Ce: YAG amount on structure and optical properties of Ce:YAG-PMMA composites for white LED
2016
Ce:YAG-poly(methyl methacrylate) (PMMA) composites were prepared by using a melt compounding method, adding several amounts of Ce:YAG in the range 0.1–5wt.%. The optical properties of the obtained composites and of the composites combined with a blue LED were measured to investigate the effect of the amount of Ce:YAG on the resulting emitted light in view of possible application in white LED manufacture. An increase in Ce:YAG amount caused an increase in the emission and a shift of 15 nm, influencing the white LED performance. The structure and morphology of the composites were studied. The results show that the interaction between the two components, observed by using solid state NMR exper…
Temporal patterns in immune responses to a range of microbial insults (Tenebrio molitor).
2008
8 pages; International audience; Much work has elucidated the pathways and mechanisms involved in the production of insect immune effector systems. However, the temporal nature of these responses with respect to different immune insults is less well understood. This study investigated the magnitude and temporal variation in phenoloxidase and antimicrobial activity in the mealworm beetle Tenebrio molitor in response to a number of different synthetic and real immune elicitors. We found that antimicrobial activity in haemolymph increased rapidly during the first 48h after a challenge and was maintained at high levels for at least 14 days. There was no difference in the magnitude of responses …