Fluorine containing self‐crosslinking acrylic latexes with reduced flammability and their application as polymer binders for heterogeneous cation‐exchange membranes

In this study, self‐crosslinking core–shell latexes comprising copolymerized perfluorethyl groups and a novel flame retardant based on phosphazene derivative were prepared by the semi‐continuous non‐seeded emulsion polymerization of 2,2,2‐trifluorethyl methacrylate, methyl methacrylate, butyl acrylate, methacrylic acid, and hexaallylamino‐cyclo‐triphosphazene as main monomers. For interfacial crosslinking, diacetone acrylamide was copolymerized into the shell layer of latex particles to provide sites for subsequent reaction with adipic acid dihydrazide. The heterogeneous cation‐exchange membranes were obtained by dispersing commercial strong acid cation‐exchange resin powder in the latex binder and casting the mixture followed by keto‐hydrazide crosslinking reaction. It was found that the increased concentration of fluorine atoms and phosphazene units in the macromolecular structure of interfacially crosslinked emulsion polymers resulted in a significant enhancement of their flame resistance and shape stability in aqueous environment. Moreover, the easily prepared heterogeneous cation‐exchange membranes based on latexes with higher amounts of fluorine and phosphazene units were shown to exhibit satisfactory physicochemical and electrochemical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45467.     

Influence of food matrix on absorption of flavour compounds by linear low‐density polyethylene: proteins and carbohydrates

The effects of differences in food matrices on the absorption of four flavour compounds (limonene, decanal, linalool and ethyl 2‐methyl butyrate) into linear low‐density polyethylene (LLDPE) were studied using a large volume injection GC ‘in vial’ extraction method. Food components investigated included β‐lactoglobulin (β‐lg), casein, pectin, carboxymethylcellulose (CMC), lactose and saccharose. β‐lg interacted irreversibly with decanal (P < 0.01) and suppressed absorption of the latter by LLDPE by more than 50% after 14 days of exposure. Casein was capable of binding limonene and decanal (p < 0.05) by hydrophobic and covalent interactions, resulting in decreased absorption of 40% and 90%, respectively. The absorption rates of limonene, and to a leaser extent decanal, were decreased in presence of pectin and CMC. Increasing viscosity slowed down diffusion of flavour compounds from the matrix to LLDPE. An increase of absorption (p < 0.01) was observed for linalool and ethyl 2‐methyl butyrate, due to a ‘salting out’ effect caused by lactose and saccharose. The absorption of decanal was decreased (p < 0.01) after 14 days of exposure in the presence of lactose, saccharose and CMC. There might be an interactive effect between a sugar (residue) and decanal. Knowledge of the composition of a food matrix and packaging material is necessary to estimate the amount of flavour absorption. © 2000 Society of Chemical Industry     

A biosensing method for detection of caffeine in coffee

A specific inhibition of 3′,5′‐cyclic phosphodiesterase (CPDE) from bovine heart by methylxanthines was used in combination with a pH electrode to develop a new biosensing method for the detection of caffeine in coffee. The potential response changes of the sensor were proportional to the concentration of caffeine in the range 0–4 mg ml⁻¹. The response time was about 2–4 min. The standard deviation of five measurements of a 0.2 mg ml⁻¹ caffeine solution was ±7.1 µg ml⁻¹. The electrode gave a detection limit of 0.6 mg l⁻¹ caffeine. The concentration of caffeine in espresso coffee was analysed. This model gave excellent correlation between observed and predicted caffeine values. This electrode exhibits advantages such as fast response, short conditioning time and low cost of the instrumentation used. We also expected to be able to perform the detection of caffeine in food and clinical analysis. © 1999 Society of Chemical Industry     

Manipulating microstructure and mechanical properties of CuO doped 3Y-TZP nano-ceramics using spark-plasma sintering

Nano-powder composites of 3Y-TZP doped with 8 mol% CuO were processed by spark-plasma sintering (SPS). A 96% dense composite ceramic with an average grain size of 70 nm was obtained by applying the SPS process at 1100 °C and 100 MPa for 1 min. In contrast to normal, pressureless, sintering during SPS reactions between CuO and 3Y-TZP were suppressed, the CuO phase was reduced to metallic Cu, while the 3Y-TZP phase remained almost purely tetragonal. Annealing after SPS results in grain growth and tetragonal to monoclinic zirconia phase transformation. The grain size and monoclinic zirconia phase content are strongly dependent on the annealing temperature. By combining the processing techniques studied in this work, including traditional pressureless sintering, properties of the composite ceramic can be tuned via manipulation of microstructure. Tuning the mechanical properties of dense 8 mol% CuO doped 3Y-TZP composite ceramic by utilising different processing techniques is given as an example.     

Reproducibility of MRI-based white matter tract estimation using multi-fiber probabilistic tractography: effect of user-defined parameters and regions

Objective

There is a pressing need to assess user-dependent reproducibility of multi-fibre probabilistic tractography in order to encourage clinical implementation of these advanced and relevant approaches. The goal of this study was to evaluate both intrinsic and inter-user reproducibility of corticospinal tract estimation.

Materials and methods

Six clinical datasets including motor functional and diffusion MRI were used. Three users performed an independent tractography analysis following identical instructions. Dice indices were calculated to quantify the reproducibility of seed region, fMRI-based end region, and streamline maps.

Results

The inter-user reproducibility ranged 41–93%, 29–94%, and 50–92%, for seed regions, end regions, and streamline maps, respectively. Differences in streamline maps correlated with differences in seed and end regions. Good inter-user agreement in seed and end regions, yielded inter-user reproducibility close to the intrinsic reproducibility (92–97%) and in most cases higher than 80%.

Discussion

Uncertainties related to user-dependent decisions and the probabilistic nature of the analysis should be considered when interpreting probabilistic tractography data. The standardization of the methods used to define seed and end regions is a necessary step to improve the accuracy and robustness of multi-fiber probabilistic tractography in a clinical setting. Clinical users should choose a feasible compromise between reproducibility and analysis duration.

     

Emissions Production from Small Heat Sources Depending on Various Aspects

Mobile Networks and Applications - Solid fuels combustion is rather complicated because there is always environment pollution by emissions, mainly by particulate matter. The efforts of heat sources...     

Historical analysis of pharmacoeconomic terms

Scientometrics - Pharmacoeconomy is a young interdisciplinary science at the intersection of pharmacy, medicine and economics, focusing on the social aspects and implications of different types of...     

Inhomogeneity of CoCrW powder products manufactured by SLM technology

Journal of Mechanical Science and Technology - The article deals with selective laser melting process using CoCrW powder. Our aim was to identify the influence of product position on the building...     

Influence of Gluten and Gum Additives and Cryogenic Treatment on Some Properties and Morphology of Wheat Starch Complex Gels

The influence of gums (guar and xanthan) and gluten additives on the physicochemical properties and structural features of wheat starch gels (8%, w/w) subjected to cryogenic treatment at various temperatures (−9°C, −20°C, −40°C) was studied. Shear modulus and breaking stress of the gels were measured, the gels' morphology was studied with optical microscopy and the local mobility of water in the gels was determined with ESR. The total concentration of polysaccharide additives did not exceed 1% (w/w), and a 65:35 (w/w) mixture of guar and xanthan gums proved to be the optimal additive, which caused a noticeable increase in rigidity and strength of the resulting complex gels. Shear modulus and breaking stress of the gels decreased with lowering the temperature of the cryogenic treatment. The heterogeneous morphology of thin sections of the gel samples was revealed via optical microscopy. ESR studies showed that the local mobility of water was much lower in the gels than in pure water.