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.     

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.     

Spray Drying of Goat Milk Protein Hydrolysates with Angiotensin Converting Enzyme Inhibitory Activity

A goat milk hydrolysate was stabilized by spray drying using different inlet air temperatures (170–230 °C) and feed flow rates (4–12 mL/min) following a central composite experimental design. In order to evaluate the effect of operational conditions on process yield, powder properties (density, moisture, hygroscopicity, and solubility) as well as angiotensin converting enzyme (ACE) inhibitory activity, experimental data were analyzed by response surface methodology. Input variables showed a significant influence on yield, density, and moisture, while hygroscopicity, solubility, and ACE inhibitory activity were not affected. The dried hydrolysate presented an average IC₅₀ value of 273.13 μg/mL, which involved a loss of 25 % in ACE inhibitory activity with respect to the feed. The variations detected in the low molecular weight fractions of the dried hydrolysates could be responsible for the variations in ACE inhibitory activity.     

Preparation and characterisation of poly(3,4-ethylenedioxythiophene) and poly(3,4-ethylenedioxythiophene)/poly(neutral red) modified carbon film electrodes, and application as sensors for hydrogen peroxide

Poly(3,4-ethylenedioxythiophene) (PEDOT) films have been prepared for the first time on carbon-film electrodes (CFE) in aqueous solution using electropolymerisation by potential cycling, potentiostatically and galavanostatically. Characterisation of the modified electrodes was done by cyclic voltammetry and electrochemical impedance spectroscopy and the stability of the polymer films was probed. The coated electrodes were tested for application as hydrogen peroxide sensors, by oxidation and reduction. A novel polymer film was also formed by modification of CFE by co-electropolymerisation of EDOT and the phenazine dye neutral red (NR) – (PEDOT/PNR) with a view to enhancing the properties for sensor applications. It was found that hydrogen peroxide reduction at the PEDOT/PNR coated electrodes could be carried out at a less negative potential, the sensor performance comparing very favourably with that of other polymer-modified electrodes reported in the literature.     

Protective Effects of Merlot Red Wine Extract and its Major Polyphenols in Pc12 Cells under Oxidative Stress Conditions

Abstract: The potential effect of the extracts from free‐run and pressed Merlot red wine has been evaluated in PC12 cells under oxidative stress situation. Comparing both vinification process, pressed Merlot red wine extract possessed higher neuroprotective activity than the free run wine, possibly attributed to the major content in all global polyphenolic families. High performance liquid chromatography determination of individual polyphenols showed that the major compounds found in Merlot red wine extract were quercetin, catechin, epicatechin, tyrosol, gallic acid, and procyanidins. Pretreatments with these polyphenolic compounds (0.25 mM and 0.1 mM, 24 h) significantly increased cell viability of H₂O₂ and Fenton reaction treated cells. Moreover, these polyphenols attenuated ROS production and decreased the Redox Index of glutathione (RI = GSSG/GSH + GSSG) in cells treated only with Fenton reaction. Furthermore, some polyphenols induced antioxidant enzymes activity and protein expression. Quercetin was the most active. These results support the beneficial effects of red wine extracts and some of its polyphenols under oxidative stress conditions. Practical Application: This research provides evidences of the preventive properties of wine extracts and its major polyphenols under oxidative stress conditions.     

Impact of cell wall‐degrading enzymes on water‐holding capacity and solubility of dietary fibre in rye and wheat bran

BACKGROUND: Rye and wheat bran were treated with several xylanases and endoglucanases, and the effects on physicochemical properties such as solubility, viscosity, water‐holding capacity and particle size as well as the chemical composition of the soluble and insoluble fractions of the bran were studied. A large number of enzymes with well‐defined activities were used. This enabled a comparison between enzymes of different origins and with different activities as well as a comparison between the effects of the enzymes on rye and wheat bran. RESULTS: The xylanases derived from Bacillus subtilis were the most effective in solubilising dietary fibre from wheat and rye bran. There was a tendency for a higher degree of degradation of the soluble or solubilised dietary fibre in rye bran than in wheat bran when treated with most of the enzymes. CONCLUSION: None of the enzymes increased the water‐holding capacity of the bran or the viscosity of the aqueous phase. The content of insoluble material decreased as the dietary fibre was solubilised by the enzymes. The amount of material that may form a network to retain water in the system was thereby decreased. © 2012 Society of Chemical Industry