Influence of the deposition parameters on the morphology and electrical conductivity of PANI/PSS self-assembled films

The influence of deposition parameters, namely polymer concentration and pH of the deposition solution, cleaning, and drying steps on the morphology and electrical characteristics of polyaniline and sulfonated polystyrene (PANI/PSS) nanostructured films deposited by the self-assembly technique is evaluated by UV–Vis spectroscopy, optical and atomic force microscopy, and electrical resistance measurements. It is found that stirring the cleaning solution during the cleaning step is crucial for obtaining homogenous films. Stirring of the cleaning solution also influences the amount of PANI adsorbed in the films. In this regard, the drying process seems to be less critical since PANI amount and film thickness are similar in films dried with N₂ flow or with an absorbent tissue. It is observed, however, that drying with N₂ flow results in rougher films. As an additional point, an assessment of the influence of the deposition method (manual versus mechanical) on the film characteristics was carried out. A significant difference on the amount of PANI and film thickness between films prepared by different human operators and by a homemade mechanical device was observed. The variability in film thickness and PANI adsorbed amount is smaller in films mechanically assembled.     

Scientific research ontology to support systematic review in software engineering

The term systematic review is used to refer to a specific methodology of research, developed in order to gather and evaluate the available evidence pertaining to a focused topic. It represents a secondary study that depends on primary study results to be accomplished. Several primary studies have been conducted in the field of Software Engineering in the last years, determining an increasing improvement in methodology. However, in most cases software is built with technologies and processes for which developers have insufficient evidence to confirm their suitability, limits, qualities, costs, and inherent risks. Conducting systematic reviews in Software Engineering consists in a major methodological tool to scientifically improve the validity of assertions that can be made in the field and, as a consequence, the reliability degree of the methods that are employed for developing software technologies and supporting software processes. This paper aims at discussing the significance of experimental studies, particularly systematic reviews, and their use in supporting software processes. A template designed to support systematic reviews in Software Engineering is presented, and the development of ontologies to describe knowledge regarding such experimental studies is also introduced.     

Multifractality in fidelity sequences of optimized Toffoli gates

We analyze the multifractality in the fidelity sequences of several engineered Toffoli gates. Using quantum control methods, we consider several optimization problems whose global solutions realize the gate in a chain of three qubits with XY Heisenberg interaction. Applying a minimum number of control pulses assuring a fidelity above 99 % in the ideal case, we design stable gates that are less sensitive to variations in the interqubits couplings. The most stable gate has the fidelity above 91 % with variations about 0.1 %, for up to 10 % variation in the nominal couplings. We perturb the system by introducing a single source of 1 / f noise that affects all the couplings. In order to quantify the performance of the proposed optimized gates, we calculate the fidelity of a large set of optimized gates under prescribed levels of coupling perturbation. Then, we run multifractal analysis on the sequence of attained fidelities. This way, gate performance can be assessed beyond mere average results, since the chosen multifractality measure (the width of the multifractal spectrum) encapsulates into a single performance indicator the spread of fidelity values around the mean and the presence of outliers. The higher the value of the performance indicator the more concentrated around the mean the fidelity values are and rarer is the occurrence of outliers. The results of the multifractal analysis on the fidelity sequences demonstrate the effectiveness of the proposed optimized gate implementations, in the sense they are rendered less sensitive to variations in the interqubits coupling strengths.     

Geodesic-driven visual effects over complex surfaces

Texture mapping is an important technique for adding visual details to geometric models. Image-based texture mapping is the most popular approach, but it relies on pre-computed images which often limit their use to static effects. For adding dynamic effects, procedural-based texturing is more adequate. Since it rely on functions to describe texturing patterns, procedural texturing allows for a more compact representation and control of visual effects by a simple change of parameters. In this work we describe GeoTextures, an approach that uses geodesic distance fields defined from multiple sources at different locations over a model surface to place, advect, and combine procedural visual effects over complex surfaces. The use of geodesics extends the scope of common procedural textures which are usually limited to using spatial 3D coordinates or 2D texture coordinates. We illustrate the flexibility of our real-time approach with a range of visual effects, such as time-based propagation of weathering phenomena, transparency effects, and mesh displacement over surfaces with smooth silhouettes using hardware based tessellation available in current graphics cards.     

Aqueous two-phase systems: a new approach for the determination of p-aminophenol

A new method has been developed for the spectrophotometric determination of p-aminophenol (PAP) in water, paracetamol formulations and human urine samples with a recovery rate between 94.9 and 101%. This method exploits an aqueous two-phase system (ATPS) liquid-liquid extraction technique with the reaction of PAP, sodium nitroprusside and hydroxylamine hydrochloride in pH 12.0, which produces the [Fe₂(CN)₁₀]¹⁰⁻ anion complex that spontaneously concentrates in the top phase of the ATPS (K[Fe₂(CN)₁₀]¹⁰⁻=97.7). The ATPS does not require an organic solvent, which is a safer and cleaner liquid-liquid extraction technique for the determination of PAP. The linear range of detection was from 5.00 to 500 μg kg⁻¹ (R ≥ 0.9990; n = 8) with a coefficient of variation of 2.11% (n = 5). The method exhibited a detection limit of 2.40 μg kg⁻¹ and a quantification limit of 8.00 μg kg⁻¹. The ATPS method showed a recovery that ranged between 96.4 and 103% for the determination of PAP in natural water and wastewater samples, which was in excellent agreement with the results of the standard 4-aminoantipyrine method that was performed on the same samples.     

Lactose-hydrolyzed milk powder: Physicochemical and technofunctional characterization

The objective of this work is to demonstrate the effect of operational drying parameters on the physicochemical and techno-functional properties of lactose-hydrolyzed milk powder (LHMP). LHMP showed water content superior to the control regardless of drying conditions, which is a direct result of the difficulties encountered in drying the product. For a lab-scale spray dryer, the LHMP produced at θ_air,in?=?145°C and m_CM?=?1.0?kg?·?h^?1 was the only sample that met all stipulated quality parameters: water content <5% (w/w), a_w?93, particle sizes similar to control, and complete rehydration.     

Effects of Purified Saccharomyces cerevisiae (1→3)-β-Glucan on Venous Ulcer Healing

Water-insoluble glucan was isolated from the baker's yeast Saccharomyces cerevisiae. The yeast cells were treated with alkali and the residue then with acid. Chemical and NMR (1D and 2D) analyses showed that a linear (1→3)-β-glucan was purified that was not contaminated with other carbohydrates, proteins or phenolic compounds. The effects of the glucan on wound healing were assessed in human venous ulcers by histopathological analysis after 30 days of topical treatment. (1→3)-β-glucan enhanced ulcer healing and increased epithelial hyperplasia, as well as increased inflammatory cells, angiogenesis and fibroblast proliferation. In one patient who had an ulcer that would not heal for over 15 years, glucan treatment caused a 67.8% decrease in the area of the ulcer. This is the first study to investigate the effects of (1→3)-β-glucan on venous ulcer healing in humans; our findings suggest that this glucan is a potential natural biological response modifier in wound healing.     

Preparation of CTAB-functionalized aqai stalk and its efficient application as adsorbent for the removal of Direct Blue 15 and Direct Red 23 dyes from aqueous media

In this work, a new adsorbent material based on the chemical modification of aqai stalk (AS) with hexadecyltrimethylammonium bromide (CTAB) was proposed, forming a new material called AS-CTAB. The characterization data from the AS-CTAB adsorbent indicated that the biomass was chemically modified by the surfactant. The prepared material was successfully used as an adsorbent for the removal of Direct Blue 15 (DB-15) and Direct Red 23 (DR-23) from aqueous solutions. For both dyes, adsorption followed the Avrami kinetic model. The kinetic data were better fitted using the nonlinear Avrami fractional model for both dyes. The contact time between the adsorbent and adsorbate was fixed at 180 and 30?min for DB-15 and DR-23, respectively. This remarkable difference of contact time between the dyes with AS-CTAB adsorbent was attributed to the difference in the physicochemical characteristics of the dyes such as size of the molecule, hydrophilic–lipophilic balance, and polar surface area (PA). The Liu isotherm model displayed Q_max of 394.2 and 454.9?mg?g^?1 for DB-15 and DR-23, respectively, at 45°C. Since the AS-CTAB is not a porous material, electrostatic interaction was the main mechanism involved in the adsorption process for both dyes. The thermodynamic adsorption reaction was shown to be a spontaneous and endothermic process. The AS-CTAB adsorbent was also tested in the treatment of synthetic dye effluents and presented a removal of up to 95.41% of a simulated effluent containing several dyes and high saline concentration.     

Preparation of mesoporous geopolymer using metakaolin and rice husk ash as synthesis precursors and its use as potential adsorbent to remove organic dye from aqueous solutions

In this work, mesoporous geopolymer was synthesized using a novel and easy synthesis route employing metakaolin and rice husk ash as sources of silica and alumina, and soybean oil as a mesostructure-directing agent. For comparison purposes, a geopolymer sample was produced without the use of oil. The samples were characterized by Fourier transform infrared spectroscopy (FT–IR), X–ray diffraction (XRD), specific surface area, pore volume, average pore size, and pore size distribution (BET and BJH methods). The materials were tested to remove methyl violet 10B dye from aqueous solutions. The results showed that the mesoporous geopolymer presented adsorptive superior behavior compared to the geopolymer prepared without the use of oil, being attributed to its superior pore properties. The adsorption equilibrium was attained within 120 min, and the maximum adsorption capacity of mesoporous geopolymer was 276.9 mg g^–1. Therefore, the mesoporous geopolymer prepared in this work comprises a potential adsorbent, presenting pore intrinsic properties that result in a high adsorption capacity.     

An immune-inspired multi-objective approach to the reconstruction of phylogenetic trees

This work presents the application of the omni-aiNet algorithm—an immune-inspired algorithm originally developed to solve single and multi-objective optimization problems—to the reconstruction of phylogenetic trees. The main goal here is to automatically evolve a population of phylogenetic unrooted trees, possibly with distinct topologies, by minimizing at the same time two optimization criteria: the minimum evolution and the mean-squared error. This proposal generates, in a single run, a set of non-dominated solutions that represent the trade-offs of the two conflicting objectives, and gives the user the possibility of having distinct explanations for the differences observed at the terminal nodes of the trees. A series of experimental results is also reported in this work, in order to illustrate the effectiveness of the proposal and its capability to overcome the restrictive feedback provided by the application of well-known algorithms for phylogenetic reconstruction, such as the Neighbor Joining. Besides, the methodology presented in this work is compared to the popular NSGA-II algorithm, also modified to solve phylogenetic reconstruction problems.