Search results for "LYST"

Catalytic transesterification of Pistacia chinensis seed oil using HPW immobilized on magnetic composite graphene oxide/cellulose microspheres

2018

Abstract In the present study, magnetic composite graphene oxide/cellulose (GO/CM@Fe3O4) microspheres were prepared as support material, which are cost-efficient, non-toxic and environmental friendly. The microspheres with higher adsorption capacity were further modified using triethylene tetramine (TETA), and H3PW12O40 (HPW) was immobilized to form GO/CM-NH2@Fe3O4-HPW microspheres as heterogeneous catalyst for biodiesel production. The novel heterogeneous catalyst was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and X-ray diffractometry (XRD). For the first time, GO/CM-NH2@Fe3O4--HPW was applied in the tr…

1992

Semi-IPN's of different composition, based on linear poly(methyl vinyl ether) (PVME) and crosslinked polystyrene are studied using stress and birefringence measurements in simple elongation. From quasistatic stress-strain experiments at constant T(experiment)-Tg, it can be deduced that the stress results only from the deformation of the polystyrene network, while the PVME chains do not contribute to the macroscopic stress. The concentration dependence of the network modulus is adequately described by the rubber elastic theories

Rapid formation of plasma protein corona critically affects nanoparticle pathophysiology

2013

In biological fluids, proteins bind to the surface of nanoparticles to form a coating known as the protein corona, which can critically affect the interaction of the nanoparticles with living systems. As physiological systems are highly dynamic, it is important to obtain a time-resolved knowledge of protein-corona formation, development and biological relevancy. Here we show that label-free snapshot proteomics can be used to obtain quantitative time-resolved profiles of human plasma coronas formed on silica and polystyrene nanoparticles of various size and surface functionalization. Complex time- and nanoparticle-specific coronas, which comprise almost 300 different proteins, were found to …

Palladium-catalyzed formation and reactions of iodo- and bromosiloxane intermediates

2012

Polysiloxanes are useful materials because of their functionality, such as high thermal stability, electrical resistance, and hydrophobicity. In this regard, we studied palladium-catalyzed formation of iodo-and bromopolysiloxanes from two types of hydrosiloxanes, alpha,omega-dihydropoly(dimethylsiloxane) (1) and cyclotetra(hydromethylsiloxane) (2), and their reactions. Treatment of 1 with mixtures of cyclic ethers or lactones and MeI or allylBr in the presence of a catalytic amount of PdCl2 gave the corresponding alpha,omega-bis(haloalkoxy and haloalkanoyloxy) poly(dimethylsiloxane)s in good yields, via iodo-and bromopoly(dimethylsiloxane) intermediates. Transformation of the iodobutoxy-ter…

Preparation of photocatalysts by physical methodologies

2021

The synthesis of photocatalytic materials is an important task for obtaining better results in terms of activity and/or selectivity in photocatalysis. This chapter reports an overview of the main methodologies using physical techniques to obtain bulky, supported powders or films and coatings to be used as heterogeneous photocatalysts. The classical chemical methodologies for the preparation of photocatalytic materials are presented in the previous chapter, so the information presented here complements the aforementioned one. Materials scientists and engineers have made significant progresses in the improvement of methods of synthesis of nanomaterial solids by developing different apparatuse…

Cationic and Zwitterionic Polymerizable Surfactants:  Quaternary Ammonium Dialkyl Maleates. 1. Synthesis and Characterization

1999

Cationic and zwitterionic reactive dialkyl maleates with different hydrophobic chain lengths (R = C10H21, C12H25, C16H33, and C18H37), and some similar surfactants without double bonds were synthesized with an aim to use them as stabilizers in the batch and seeded emulsion copolymerization of styrene and butyl acrylate (part 2 of this series). Surfactants are obtained in a three-step synthesis, starting from ring opening of maleic anhydride, followed by O alkylation with an aminoalkyl compound, and finishing with quaternization of the amino group in the hydrophilic part of the molecule. The chemical structure of surfactants was confirmed by 1H NMR. Melting points and critical micelle concen…

Preservation of dendritic cell function upon labeling with amino functionalized polymeric nanoparticles.

2010

Dendritic cells (DCs) are key players in eliciting immunity against antigens, therefore making them the focus of many investigations on immune responses in infections, cancer and autoimmune diseases. Nanosized materials have just recently been investigated for their use as carriers of antigens and as labeling agents for DCs. For this later use nanoparticles should be non-toxic and should most importantly not alter the physiological functions of DCs. Here we demonstrate that by the use of polymeric fluorescent nanoparticles as synthesized by the miniemulsion process immature DCs (iDCs) can be efficiently labeled intracellularly. Amino functionalized nanoparticles are more effective than carb…

Functionalized Polystyrene Nanoparticles Trigger Human Dendritic Cell Maturation Resulting in Enhanced CD4+T Cell Activation

2012

Nanoparticles (NP) represent a promising tool for biomedical applications. Here, sulfonate- and phosphonate-functionalized polystyrene NP are analyzed for their interaction with human monocyte-derived dendritic cells (DC). Immature dendritic cells (iDC) display a higher time- and dose-dependent uptake of functionalized polystyrene NP compared to mature dendritic cells (mDC). Notably, NP induce an enhanced maturation of iDC but not of mDC (upregulation of stimulatory molecules and cytokines). NP-triggered maturation results in a significantly enhanced T cell stimulatory capacity (increased CD4(+) T cell proliferation and IFN-γ production), indicating a shift to a pronounced Th1 response. Imm…

Phytosociological remarks on residual woodlands of Laurus nobilis in Sicily

2010

A phytosociological study was done of Laurus nobilis woodlands in Sicily. The analysis, based on 18 relevés, supports the definition of a new syntaxon (Acantho mollis-Lauretum nobilis ass. nov.), considered as a vicariant of similar vegetation aspects described in other Mediterranean areas (Iberian and Italian peninsulas). The study mainly includes some unpublished sites where polycormic individuals of laurel, sometimes reaching 13-15 meters in height, dominates the tree layer. This vegetation is also characterized by some laurophyllous species (Hedera helix, Rhamnus alaternus, Smilax aspera and sometimes Viburnum tinus) and lianas (Rubia peregrina var. longifolia, Asparagus acutifolius, Ta…

Dynamic thermal expansivity near the glass transition

2000

Dielectric techniques were used to investigate the thermal expansivity of polystyrene films. Capacitive scanning dilatometry (CSD) employs temperature ramping in order to monitor the non-linear structural relaxation in the glass transformation range and to quantify liquid fragility. In the linear response regime, the complex thermal expansivity is obtained as a function of the temperature cycling frequency and is observed to reflect the structural relaxation.