Sewage sludge coke estimation using thermal analysis

The imposition of more stringent legislation by CETESB in the State of São Paulo (Brazil) governing the disposal and utilization of sewage sludge, coupled with the growth in its generation has prompted a drive for alternative uses of sewage sludge. One option that is especially promising, due to its potential to valorize sludge, is its conversion into carbonaceous adsorbents or coke for industrial effluents treatment. Thus, a methodology is presented to estimate the coke produced from the sludge of a sewage treatment station using thermal analysis. The used sewage sludge, which comes from aerobic treatment, was collected in the wastewater treatment station of Barueri, one of the largest of the São Paulo metropolitan area. The sludge samples were collected, dried, ground, and milled until they passed an ABNT 200 sieve. The inert ambient used during its thermal treatment produces inorganic matter and coke as residual materials. Coke formation occurs in the 200–500 °C range and, between 500 and 900 °C, its thermal decomposition occurs. The highest formation of coke occurs at 500 °C.     

Study of the thermal behavior of the transition phase of Co(II)–diclofenac compound by non-isothermal method

The Co(II)–diclofenac complex was evaluated by simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The DTA curve profile shows one exothermic peak because of the transition phase of the compound between 170 and 180 °C, which was confirmed by X-ray powder diffractometry. The transition phase behavior was studied by DSC curves at several heating rates of a sample mass between 1 and 10 mg in nitrogen atmosphere and in a crucible with and without a lid. Thus, the kinetic parameters were evaluated using an isoconversional non-linear fitting proposed by Capela and Ribeiro. The results show that the activation energy and pre-exponential factor for the transition phase is dependant on the different experimental conditions. Nevertheless, these results indicate that the kinetic compensation effect shows a relationship between them.     

Anti-inflammatory activity of alkaloids: an update from 2000 to 2010

Many natural substances with proven anti-inflammatory activity have been isolated throughout the years. The aim of this review is to review naturally sourced alkaloids with anti-inflammatory effects reported from 2000 to 2010. The assays were conducted mostly in vivo, and carrageenan-induced pedal edema was the most used experimental model. Of the 49 alkaloids evaluated, 40 demonstrated anti-inflammatory activity. Of these the most studied type were the isoquinolines. This review was based on NAPRALERT data bank, Web of Science and Chemical Abstracts. In this review, 95 references are cited.     

Study of double perovskite La2B(II)MnO6 (B: Ni,Co, Cu) as electrode materials for energy storage

Journal of Solid State Electrochemistry - In this paper, the study of the potential capacity of energy storage in supercapacitors containing oxide La2B(II)MnO6 (with B = Cu, Co, Ni) as...     

Nonlinear screening in multilayer graphene systems

Electrostatic screening in multilayer graphene is highly nonlinear due to the vanishing density of states at the Fermi level. Using a discrete model we study the charge screening normal to the layers. Our model shows a strong charge and temperature dependence and has a simple continuum limit at T=0 for undoped systems. Doped systems can exhibit more complex behavior due to minority-carrier screening. Most importantly we find that the screening length can vary more than an order of magnitude depending on the experimental conditions, reconciling the large range of screening lengths reported in previous experiments. This has important consequences for technological applications of multilayer graphene used in electrodes or transistor channels.     

Surfaces of Rotation with Constant Extrinsic Curvature in a Conformally Flat 3-Space

In this work, we relate the extrinsic curvature of surfaces with respect to the Euclidean metric and any metrics that are conformal to the Euclidean metric. We introduce the space ${\mathbb{E}_3}$ ??the 3-dimensional real vector space equipped with a conformally flat metric that is a solution of the Einstein equation. We characterize the surfaces of rotation with constant extrinsic curvature in the space ${\mathbb{E}_3}$ . We obtain a one-parameter family of two-sheeted hyperboloids that are complete surfaces with zero extrinsic curvature in ${\mathbb{E}_3}$ . Moreover, we obtain a one-parameter family of cones and show that there exists another one-parameter family of complete surfaces of rotation with zero extrinsic curvature in ${\mathbb{E}_3}$ . Moreover, we show that there exist complete surfaces with constant negative extrinsic curvature in ${\mathbb{E}_3}$ . As an application we prove that there exist complete surfaces with Gaussian curvature K ?? ? ?? < 0, in contrast with Efimov??s Theorem for the Euclidean space, and Schlenker??s Theorem for the hyperbolic space.     

Three-dimensional large deformation analysis of thin walled beams

A set of kinematic assumptions and constraints is used to develop a formulation for the analysis of thin-walled beams, of arbitrary open cross-section, subjected to arbitrarily large displacements in three-dimensional space. The validity of the formulation is illustrated through numerical solutions for elastic lateral-torsional post-buckling behavior of “I” beams, and a comparison of these solutions with experimental results.     

Citrinin (CIT) determination in rice samples using a micro fluidic electrochemical immunosensor

The development of an electrochemical immunosensor incorporated in a micro fluidic cell for quantification of citrinin (CIT) mycotoxin in rice samples is described for the first time. Both CIT present in rice samples and immobilized on a gold surface electrodeposited on a glassy carbon (GC) electrode modified with a cysteamine self-assembled monolayer were allowed to compete for the monoclonal mouse anti-CIT IgG antibody (mAb-CIT) present in solution. Then, an excess of rabbit anti mouse IgG (H + L) labelled with the horseradish peroxidase (secAb-HRP) was added, which reacts with the mAb-CIT which is in the immuno-complex formed with the immobilized CIT on the electrode surface. The HPR, in the presence of hydrogen peroxide (H₂O₂) catalyzes the oxidation of catechol (H₂Q) whose back electrochemical reduction was detected on a GC electrode at −0.15 V vs Ag/AgCl by amperometric measurements. The current measured is proportional to the enzymatic activity and inversely proportional to the amount of CIT present in the rice samples. This immunosensor for CIT showed a range of work between 0.5 and 50 ng mL⁻¹. The detection (LOD) and the quantification (LOQ) limits were 0.1 and 0.5 ng mL⁻¹, respectively. The coefficients of variation intra- and inter-assays were less than 6%. The electrochemical detection could be done within 2 min and the assay total time was 45 min. The immunosensor was provided to undertake at least 80 determinations for different samples with a minimum previous pre-treatment. Our electrochemical immunosensor showed a higher sensitivity and reduced analysis time compared to other analytical methods such as chromatographic methods. This methodology is fast, selective and very sensitive. Thus, the immunosensor showed to be a very useful tool to determine CIT in samples of cereals, mainly rice samples.     

Comparative analysis of nanocomposites based on polypropylene and different montmorillonites

Nanocomposites of polypropylene (PP) were prepared by melt mixing using maleic anhydride modified polypropylene (PPg) and different organophilic montmorillonites (OMMT). The selected organo-modified clays differ in their initial particle size, amount and type of surfactant and/or their cation-exchange capacity. All composites have 80, 15 and 5 wt% of PP, PPg and OMMT, respectively. The materials were characterized using TGA, XRD, SEM and rotational rheometry. Cloisite 15A, Cloisite 93A, Nanomer I44 and a bentonite modified with octadecylammonium (B18) display intercalation and exfoliation after mixing and annealing and produce nanocomposites with different degrees of ‘solid-like’ rheological behavior. The composites based in Cloisite 15A and Nanomer I44, which use the same intercalant, show very similar phase structure and rheological response, regardless of the origin and initial characteristics of the clays. These nanocomposites are the most affected by the thermal history during rheological characterization in the molten state. On the other hand, Cloisite 10A and Cloisite 30B display collapse of the silicate layers after compounding with no evidence of exfoliation.     

An N-capping asparagine–lysine–proline (NKP) motif contributes to a hybrid flexible/stable multifunctional peptide scaffold

Structural diversity drives multiple biological activities and mechanisms of action in linear peptides. Here we describe an unusual N-capping asparagine-lysine-proline (NKP) motif that confers a hybrid multifunctional scaffold to a computationally designed peptide (PaDBS1R7). PaDBS1R7 has a shorter α-helix segment than other computationally designed peptides of similar sequence but with key residue substitutions. Although this motif acts as an α-helix breaker in PaDBS1R7, the Asn5 presents exclusive N-capping effects, forming a belt to establish hydrogen bonds for an amphipathic α-helix stabilization. The combination of these different structural profiles was described as a coil/N-cap/α-helix scaffold, which was also observed in diverse computational peptide mutants. Biological studies revealed that all peptides displayed antibacterial activities. However, only PaDBS1R7 displayed anticancer properties, eradicated Pseudomonas aeruginosa biofilms, decreased bacterial counts by 100–1000-fold in vivo, reduced lipopolysaccharide-induced macrophages stress, and stimulated fibroblast migration for wound healing. This study extends our understanding of an N-capping NKP motif to engineering hybrid multifunctional peptide drug candidates with potent anti-infective and immunomodulatory properties.

An unusual N-capping asparagine-lysine-proline (5NKP7) motif yields a coil/N-cap/α-helix multifunctional scaffold in a computer-made peptide selective for anionic surfaces and with anticancer, antibacterial, antibiofilm, anti-infective (in vivo), and immunomodulatory potential.