Sustained release of potassium diclofenac from a pH‐responsive hydrogel based on gum arabic conjugates into simulated intestinal fluid

This work describes the preparation, the swelling properties and the potassium diclofenac (KDF) release profile of hydrogels of gum arabic (GA), N′,N′‐dimethylacrylamide, and methacrylic acid. In order to convert GA into a hydrogel, the polysaccharide was vinyl‐modified with glycidyl methacrylate. The hydrogels showed pH‐responsive swelling changes, which were more expressive in the basic environment. Release data of KDF were adjusted to a diffusion‐based kinetic model that provides an important insight on affinity of the drug for hydrogel and solvent, which may be the leading parameter for release of guest molecules from polymers. The KDF release from the hydrogels into simulated intestinal fluid decreases when the amount of modified GA increases. This was demonstrated to be due to the higher affinity of KDF for GA‐richer hydrogel, which makes the anti‐inflammatory release less favorable. The analysis of released drug half‐time (t_1/2 = 16.10 and 21.51 h) indicated sustained release characteristics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43319.     

Optimization of wastes content in ceramic tiles using statistical design of mixture experiments

Mineral extraction and processing industries have been cited as sources of environmental contamination and pollution. The inclusion of wastes into productive cycles represents an alternative form of restoration, which is interesting from both environmental and economic standpoints. In this work, the development of ceramic tile formulations containing kaolin processing and granite sawing wastes was investigated using the statistical design of mixture experiments methodology. Ten formulations using the raw materials, red clay, kaolin processing and granite sawing wastes, were selected and used in the mixture design. Test specimens were fired and characterized to determine their water absorption, linear firing shrinkage and modulus of rupture. Regression models were calculated, correlating the properties with the composition. The significance and validity of the models were confirmed by statistical analysis and verification experiments. The regression models were used to optimize the waste content in ceramic compositions. The results showed that formulations containing up to 62% of waste could be used in the production of ceramic tiles.     

Preparation of Cordierite Materials with Tailored Porosity by Gelcasting with Polysaccharides

This paper deals with the rheological characterization of agar and foaming surfactant-containing suspensions for obtaining stoichiometric cordierite samples with tailored open macroporosity and their characterization through density and microstructural studies. The influence of the processing parameters solid loading (20, 30, and 45 vol%), slip temperature (65°C, 45°C, and 40°C), and agar/surfactant ratio (10.2, 8.0, and 5.6) on the obtained bodies is discussed. Open Porosity (up to 76 vol%) and average cell size were found to be strongly dependent on solids loading.     

Evaluation of the removal of n-butanol vapor by the poly(lactic acid)-zeolite-TiO2 composite and formation of by-products

The use of polymeric films incorporated with zeolite-TiO₂ composites associated with UV radiation can be an alternative in the removal of volatile organic compounds (VOCs) through the adsorption and photodegradation processes. This study produced poly(lactic acid) (PLA) films incorporated with 13× zeolite, TiO₂, and 13×-TiO₂ zeolite composite to remove n-butanol and evaluate the by-products generated in the process. The results showed that 13× zeolite and TiO₂ added individually or as a composite to PLA, gave the polymer matrix a significant increase in the removal capacity of n-butanol. The best performance was presented by the zeolite-TiO₂, composite, confirming a synergistic effect. However, the formation of CO and CO₂ exceeded the expected values, with the verification that the polymeric matrix underwent photodegradation action by TiO₂. The polymeric film only containing zeolite is the most suitable for the removal of VOCs, as it did not present degradation of the PLA, generating a lower concentration of by-products.     

A theoretical and experimental study of phosphate ester inhibitors for AISI 1018 in carbon dioxide-saturated 3.5 wt% NaCl solution

Phosphate ester was investigated as a corrosion inhibitor for AISI 1018 carbon steel in carbon dioxide-saturated chloride solutions at different temperatures and pressures. The corrosion tests were realized by electrochemical techniques, weight loss measurements, bubble tests, and a high-pressure/high-temperature autoclave system. The corrosion tests demonstrated that the investigated molecule is an excellent corrosion inhibitor. The inhibiting effect is even bigger at high pressure and temperature than at atmospheric pressure and room temperature. The thermodynamic parameters were calculated and determined to obey the Langmuir isotherm. Polarization studies revealed that the evaluated inhibitor is a mixed type.     

Ethylene and Nitric Oxide Involvement in the Regulation of Fe and P Deficiency Responses in Dicotyledonous Plants

Iron (Fe) and phosphorus (P) are two essential elements for plant growth. Both elements are abundant in soils but with poor availability for plants, which favor their acquisition by developing morphological and physiological responses in their roots. Although the regulation of the genes related to these responses is not totally known, ethylene (ET) and nitric oxide (NO) have been involved in the activation of both Fe-related and P-related genes. The common involvement of ET and NO suggests that they must act in conjunction with other specific signals, more closely related to each deficiency. Among the specific signals involved in the regulation of Fe- or P-related genes have been proposed Fe-peptides (or Fe ion itself) and microRNAs, like miR399 (P), moving through the phloem. These Fe- or P-related phloem signals could interact with ET/NO and confer specificity to the responses to each deficiency, avoiding the induction of the specific responses when ET/NO increase due to other nutrient deficiencies or stresses. Besides the specificity conferred by these signals, ET itself could confer specificity to the responses to Fe- or P-deficiency by acting through different signaling pathways in each case. Given the above considerations, there are preliminary results suggesting that ET could regulate different nutrient responses by acting both in conjunction with other signals and through different signaling pathways. Because of the close relationship among these two elements, a better knowledge of the physiological and molecular basis of their interaction is necessary to improve their nutrition and to avoid the problems associated with their misuse. As examples of this interaction, it is known that Fe chlorosis can be induced, under certain circumstances, by a P over- fertilization. On the other hand, Fe oxides can have a role in the immobilization of P in soils. Qualitative and quantitative assessment of the dynamic of known Fe- and P-related genes expression, selected ad hoc and involved in each of these deficiencies, would allow us to get a profound knowledge of the processes that regulate the responses to both deficiencies. The better knowledge of the regulation by ET of the responses to these deficiencies is necessary to properly understand the interactions between Fe and P. This will allow the obtention of more efficient varieties in the absorption of P and Fe, and the use of more rational management techniques for P and Fe fertilization. This will contribute to minimize the environmental impacts caused by the use of P and Fe fertilizers (Fe chelates) in agriculture and to adjust the costs for farmers, due to the high prices and/or scarcity of Fe and P fertilizers. This review aims to summarize the latest advances in the knowledge about Fe and P deficiency responses, analyzing the similarities and differences among them and considering the interactions among their main regulators, including some hormones (ethylene) and signaling substances (NO and GSNO) as well as other P- and Fe-related signals.     

Influence of the type and the comonomer contents on the mechanical behavior of ethylene/α‐olefin copolymers

The influences of the type and concentration of α‐olefin (1‐hexene, 1‐octene, 1‐decene, 1‐octadecene, 4‐methyl‐1‐pentene) on the mechanical behavior and crystallinity degree of some ethylene/α‐olefin copolymers obtained by metallocene catalysts were studied by means of stress/strain experiments. The crystallinity degree of these copolymers has been determined by X‐ray measurements. It has been observed that the copolymers show less resistance to strain as the comonomer content increases and the crystallinity decreases. Most of the studied copolymers exhibit a significant increase in the crystallinity level after the stress/strain experiments. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1194–1200, 1999     

Warm asphalt mixtures produced with addition of CCBit

There is a growing concern with the environmental damage caused by the various types of industrial activities. Because of that, research in paving has sought alternatives to reduce fuel consumption and emissions of greenhouse gases generated by those. The warm mixtures have received increasing attention because they are capable of decreasing the mixture and compaction temperatures of asphalt mixtures. The objective of this study was to evaluate the effect of the incorporation of CCBit from the mechanical characterization of asphalt mixtures. From the results, it was found that the incorporation of CCBit has the advantage of reducing mixing and compaction temperatures without harming their mechanical behavior.     

In situ spectroscopy studies of ethanol oxidation reaction using a single fuel cell/ATR-FTIR setup

This work presents a new method to study the ethanol oxidation reaction in a functional fuel cell adapting the single cell on an ATR-FTIR accessory. Using this configuration it was possible to observe the formation of the main products — acetaldehyde and acetic acid — and also measure the decay of the ethanol concentration at various temperatures. Furthermore, it was ascertained that the increment of power density with the temperature increase in the Pt/C anode fuel cell favors the acetaldehyde production. The proposed setup is a very promising characterization technique for studies of in situ electrochemical oxidation of small organic molecules.     

Viral pollution determination of superficial waters (river water and sea-water) from the urban area of Barcelona (Spain)

Various surface water systems in the metropolitan area of Barcelona (Spain), including two rivers and three beaches, were analysed for human viruses using glass powder as adsorbent to concentrate them. The method used allows concentration of large volumes (up to 2001), of water in a single step. Values obtained varied from 18.4 to values higher than 55 MPNCU 1⁻¹in the Besôs river and 0.44-44 MPNCU 1⁻¹in the Llobregat river. Viruses were isolated from approx. 70% of sea-water samples, the values ranging from 0 to 1.60 MPNCU 1⁻¹. Findings are discussed in terms of correlation between virus pollution and bacterial indicators of fecal contamination. Also, the suitability of glass powder adsorption to concentrate viruses in sea-water is discussed.