Oligomeric Composition of Polyols From Fatty Acid Methyl Ester: The Effect of Ring‐Opening Reactants of Epoxide Groups

Commercial availability of fatty acid methyl ester (FAME) from palm oil targeted for biodiesel offers a good feedstock for the production of structurally well‐defined polyols for polyurethane applications. The effect of molecular weight (MW), odd and even carbon numbers, and the linear and branched structure reactants used in the ring‐opening reaction of epoxidized fatty acid methyl ester (E‐FAME) on the properties of polyols was investigated. Conversions of E‐FAME to PolyFAME polyols were confirmed by Fourier transform infrared analysis, oxirane oxygen content, and hydroxyl number. Gel permeation chromatography (GPC) calibrated against polyether polyols as a standard and vapor pressure osmometry were used for MW determination. GPC chromatograms of PolyFAME polyols clearly demonstrated the formation of oligomers during ring‐opening reactions. MW, and odd and even carbon numbers in a structure of linear diols and branched diol used in the syntheses of PolyFAME polyols did not have an effect on crystallinity, glass transition, or melt temperatures measured using Differential scanning calorimetry (DSC). PolyFAME polyols ring‐opened with water, methanol, and 1,2‐propanediol contained secondary hydroxyl groups, whereas PolyFAME polyols ring‐opened with linear diols contained a mixture of primary and secondary hydroxyl groups. It was found that the concentration of primary hydroxyl groups increased significantly by increasing the number of carbons from C2 to C3 in the linear diols. The viscosity of PolyFAME polyols also increased with the MW of linear diols used in the E‐FAME ring‐opening reaction. These findings would be beneficial for formulators in choosing the most cost effective polyols for polyurethane formulations.     

A DMA study of the interfacial changes on injection‐molded iPP/mica composites modified by a p‐phenylen‐bis‐maleamic acid grafted atactic polypropylene

Present work concerns to the study of the dynamic mechanical and thermal responses of selected polypropylene (iPP)/mica composites with a modified interface from the matrix side by using a p‐phenylen‐bis‐maleamic acid grafted atactic polypropylene, coming from a byproduct of industrial polymerization reactors. Thus, the study is mainly focused on the 75/25 iPP/mica ratio since it was identified in previous works as providing the maximum inter mica particle distance to assure they should participate in the overall process of dissipation of the mechanical energy supplied to the composites. Hence, the present dynamic mechanical analysis discussion tries to correlate the damping responses of the injection‐molded composites with those previously obtained but over compression molded composites as the basis of further studies all along the compositional iPP/mica map. Therefore, the latter let us, on the one hand, to follow how the main values of the different dynamic mechanical analysis parameters vary because of the interfacial modifier presence, and on the other, to develop a robust correlation between them and the corresponding macroscopic mechanical parameters. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45366.     

Fitting success for three multifocal designs: Multicentre randomised trial

Purpose

To determine if the discontinuation of commercially-available simultaneous vision Multifocal Soft Contact Lenses is independent from the multifocal design. To determine causes for discontinuation and psychosocial factors involved.

Interaction of erythrocytes with magnetic nanoparticles

Internalization of biocompatible magnetic nanoparticles by red blood cells (RBCs) is a key issue for opportunities of new applications in the biomedical field. In this study, we used in vitro tests to provide evidences of magnetic nanoparticle internalization by mice red blood cells. The internalization process depends upon the nanoparticle concentration and the nanoparticle hydrodynamic radii. The cell internalization of surface-coated maghemite nanoparticles was indirectly tracked by Raman spectroscopy and directly observed using transmission electron microscopy. The observation of nanoparticle cell uptaking using in vitro experiments represents an important breakthrough for the application of nanomagnetism in diagnosis and therapy of RBC-related diseases.     

Influence of yeast strain on ochratoxin A content during fermentation of white and red must

The aim of this work was to examine whether the yeast strains, responsible for alcoholic fermentation, have an influence on the concentration of ochratoxin A (OTA) in wine. Before the fermentation, OTA was added to musts up to a concentration of about 2 microg/l. OTA content was determined in white and red wines resulting from respective musts and in methanolic extract of the yeast lees (MEL). Data showed a significant reduction of OTA at the end of alcoholic fermentation. However, depending on the yeast strain involved in the fermentation, there was a difference in the content of OTA in the wines. The percentage of OTA removal during the fermentation was between 46.83% and 52.16% in white wine and between 53.21% and 70.13% in red wine. The absence of degradation products suggested an adsorption mechanism. OTA concentration in MEL resulting from red must fermentation was higher than in white. A significant amount of OTA was not recovered either from wine or from MEL.     

Production of biogenic amines by lactic acid bacteria: screening by PCR, thin-layer chromatography, and high-performance liquid chromatography of strains isolated from wine and must

Biogenic amines are frequently found in wine and other fermented food. We investigated the ability of 133 strains of lactic acid bacteria isolated from musts and wines of different origins to produce histamine, tyramine, and putrescine. We detected the genes responsible for encoding the corresponding amino acid decarboxylases through PCR assays using two primer sets for every gene: histidine decarboxylase (hdc), tyrosine decarboxylase (tdc), and ornithine decarboxylase (odc); these primers were taken from the literature or designed by us. Only one strain of Lactobacillus hilgardii was shown to possess the hdc gene, whereas four strains of Lactobacillus brevis had the tdc gene. None of the Oenococcus oeni strains, the main agents of malolactic fermentation, was a biogenic amine producer. All PCR amplicon band-positive results were confirmed by thin-layer chromatography and high-performance liquid chromatography analyses.     

Dithizone modified gold nanoparticles films for potentiometric sensing

For the first time, application of a membrane composed of gold nanoparticles decorated with complexing ligand for potentiometric sensing is shown. Gold nanoparticles drop cast from a solution form a porous structure on a substrate electrode surface. Sample cations can penetrate the gold nanoparticles layer and interact with ligand acting as a charged ionophore, resulting in Nernstian potentiometric responses. Anchoring of complexing ligand on the gold surface abolishes the necessity of ionophore application. Moreover, it opens the possibility of preparation of potentiometric sensors using chelators of significantly different selectivity patterns further enhanced by the absence of polymeric membrane matrix. This was clearly seen, for example, for gold nanoparticles stabilizing the applied ligand-dithizone-thiol conformation leading to a high potentiometric selectivity toward copper ions, much higher than that of ionophores typically used to induce selectivity for polymeric ion-selective membranes.     

Cancer‐Cell‐Specific Induction of Apoptosis Using Mesoporous Silica Nanoparticles as Drug‐Delivery Vectors

Targeted delivery of the chemotherapeutic agent methotrexate (MTX) to cancer cells using poly(ethyleneimine)‐functionalized mesoporous silica particles as drug‐delivery vectors is reported. Due to its high affinity for folate receptors, the expression of which is elevated in cancer cells, MTX serves as both a targeting ligand and a cytotoxic agent. Enhanced cancer‐cell apoptosis (programmed cell death) relative to free MTX is thus observed at particle concentrations where nonspecific MTX‐induced apoptosis is not observed in the nontargeted healthy cell line, while corresponding amounts of free drug affect both cell lines equally. The particles remain compartmentalized in endo‐/lysosomes during the time of observation (up to 72 h), while the drug is released from the particle only upon cell entry, thereby inducing selective apoptosis in the target cells. As MTX is mainly attached to the particle surface, an additional advantage is that the presented carrier design allows for adsorption (loading) of additional drugs into the pore network for therapies based on a combination of drugs.     

Liquid Chromatography-Mass Spectrometry in the Analysis of Pesticide Residues in Food

The analysis of pesticide residues in food is nowadays an increasingly important task. Quality control has to be very strict in order to safeguard the consumers’ health. One of the most important goals of food quality assurance is testing food for residues and contaminants. Among chemical hazards, the contamination of food with pesticides has been characterized as a significant source of many serious diseases. Consumption of food containing pesticide residues may cause cancer, malformations, and damage to the endocrine, nervous, and immune system. In order to assure human food safety, The European Community has established maximum residue limits (MRL) of pesticides permitted in products of animal or vegetable origin that are intended for human consumption. In the EU, Regulation (EC) No. 396/2005 of the European Parliament and Council on pesticide residues established the levels of pesticide residues allowed in food and feed. To ensure the compliance of marketed food commodities with the law on food safety, sensitive and reliable analytical methods for the determination of pesticide residues are required. Multiresidue liquid chromatography-mass spectrometry methods (LC-MS) are widely recognized as an ideal, highly specific, and extremely sensitive technique for testing food products. This review discusses LC-MS approaches applied most widely to pesticide residue analysis over the last few years. The main ionization methods and MS detectors used as analytical tools in quantification and/or identification/confirmation of pesticide residues in food are presented.