Polyluminol/hydrogel composites as new electrochemiluminescent-active sensing layers

This paper reports on electrochemiluminescent sensors and biosensors based on polyluminol/hydrogel composite sensing layers using chemical or biological membranes as hydrogel matrices. In this work, luminol is electropolymerized under near-neutral conditions onto screen-printed electrode (SPE)-supported hydrogel films. The working electrode coated with a hydrogel film is soaked in a solution containing monomeric luminol units, allowing the monomeric luminol units to diffuse inside the porous matrix to the electrode surface where they are electropolymerized by cyclic voltammetry (CV). Sensors and enzymatic biosensors for H₂O₂ and choline detection, respectively, have been developed, using choline oxidase (ChOD) as a model enzyme. In this case, hydrogel is used both as the enzymatic immobilization matrix and as a template for the electrosynthesis of polyluminol. The enzyme was immobilized by entrapment in the gel matrix during its formation before electropolymerization of the monomer. Several parameters have been optimized in terms of polymerization conditions, enzyme loading, and average pore size. Using calcium alginate or tetramethoxysilane (TMOS)-based silica as porous matrix, H₂O₂ and choline detection are reported down to micromolar concentrations with three orders of magnitude wide dynamic ranges starting from 4?×?10^?7 M. Polyluminol/hydrogel composites appear as suitable electrochemiluminescence (ECL)-active sensing layers for the design of new reagentless and disposable easy-to-use optical sensors and biosensors, using conventional TMOS-based silica gel or the more original and easier to handle calcium alginate, reported here for the first time in such a configuration, as the biocompatible hydrogel matrix. Figure

Elaboration of electrochemiluminent polyluminol/hydrogel composite sensing layers     

Synthesis,characterization and controlled toxicity of a novel hybrid material based on cisplatin and docetaxel

This paper is focused on the synthesis and characterization of a novel hybrid material based on cisplatin and docetaxel-loaded functionalized simultanously carbon nanotubes able to be used in cancer therapy as drug delivery system with controlled toxicity. This material was physico-chemically investigated by determining the structure, as evidenced by Fourier transform infrared (FTIR) spectroscopy, transmission electronmicroscopy (TEM) and its stability was studied with the aid of thermogravimetric analysis (TGA). The amount of platinum ions released into the solution of simulated body fluid (SBF) was highlighted by coupled plasma mass spectrometry (ICP-MS). Toxicology experiments were performed with MDA-MB 231 breast cancer epithelial cells. The performance of the new drug delivery hybrid material was compared with functionalised carbon nanotubes with therapeutic agents functionalized with a single therapeutic agent.      

The Qualitative Analysis and the Critical Hypersurfaces of Elliptic and Hyperbolic PDEs

Many boundary value problems of PDEs of the applied mathematics lead to the solving of equivalent elliptic and hyperbolic quadratic algebraic equations (QAEs) with variable coefficients. The qualitative analysis of elliptic and hyperbolic QAEs is started here by the determination of their behaviors by systematical variation of their free and linear terms, from −∞ to +∞ and by their visualization. It comes out that, for these variations of their coefficients, the elliptic and hyperbolic QAEs have critical hypersurfaces, which are obtained by cancellation of their great determinant as in [1], [2]. The critical hypersurface can be considered as a limit of existence of real solutions of an elliptic QAE. The hyperbolic QAE degenerates jumps and breaks along its critical hypersurface, which is also its asymptote. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

One step nanoencapsulation of corrosion inhibitors for gradual release application

The direct application of corrosion inhibitors on metal surfaces is potentially dangerous for the environment and the restoration operators, thus new conservation strategies are mandatory. In this study, two copper corrosion inhibitors, 1H-benzotriazole (BTA) and 5-phenyl-1H-tetrazole (PT), are encapsulated in a silica nanocontainer, for future application in smart coatings, with the aim to reduce the amount of chemicals used in treatments, their dispersion in the environment and the direct exposure of the operators to these chemicals. In particular, composite silica nanocapsules, containing the corrosion inhibitors, are prepared via one-step synthesis, based on mini-emulsion polymerisation processes.The morphology, structure, and texture of these loaded silica nanocontainers are characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ physisorption (BET/BJH). Micro-Raman spectroscopy (RS) is performed to characterise the composition. UV–visible spectroscopy and thermal analysis (TG/DSC) are performed for the loading and encapsulation efficiency (L%, EE%) study.Synthesised nanocapsules show a core-shell structure and, when loaded with the inhibitors, have size ranging from about 130 to 170 nm and a BET surface area of the order of 800 m²/g. The EE% is maximum in the case of BTA and decreases to ～52% in the case of PT.     

Rational Development of a Metal-Free Bifunctional System for the C−H Activation of Methane: A Density Functional Theory Investigation

The activation or heterolytic splitting of methane, a challenging substrate usually restricted to transition metals, has so far proven elusive in experimental frustrated Lewis pair (FLP) chemistry. In this article, we demonstrate, using density functional theory (DFT), that 1-aza-9-boratriptycene is a conceptually simple intramolecular FLP for the activation of methane. Systematic comparison with other FLP systems allows to gain insight into their reactivity with methane. The thermodynamics and kinetics of methane activation are interpreted by referring to the analysis of the natural charges and by employing the distortion-interaction/activation strain (DIAS) model. These showed that the nature of the Lewis base influences the selectivity over the reaction pathway, with N Lewis bases favoring the deprotonation mechanism and P bases the hydride abstraction one. The lower barrier of activation for 1-aza-9-boratriptycene and the higher products stability are due to a better interaction energy than its counterparts, itself due to electrostatic interactions with the methane moiety, favorable orbital overlaps allowed by the side-attack, and space proximity between the B and N atoms.     

Impact of Matrix Metalloproteinase-9 during Periodontitis and Cardiovascular Diseases

Matrix metalloproteinase-9 (MMP-9) has been shown to play a key role in endothelial function and perhaps pivotal in the correlation between periodontal disease and cardiovascular disease (CVD). For the study, the impact of MMP-9 of periodontitis and CVD on serum and saliva concentrations was analyzed. For the study patients with periodontitis (n = 31), CVD (n = 31), periodontitis + CVD (n = 31), and healthy patients (n = 31) were enrolled. Clinical and demographic characteristics as well as serum and salivary MMP-9 were evaluated. MMP-9 concentrations in serum and saliva were statistically elevated in patients with CVD (p < 0.01) and in patients with periodontitis plus CVD (p < 0.001) compared to patients with periodontitis and healthy subjects. Multivariate regression analysis showed that c-reactive protein (hs-CRP) was the only significant predictor for MMP-9 serum (p < 0.001), whereas hs-CRP (p < 0.001) and total cholesterol (p = 0.029) were the statistically significant salivary MMP-9 predictors. This study evidenced that patients with CVD and periodontitis + CVD presented elevated MMP-9 concentrations in serum and saliva compared to patients with periodontitis and healthy subjects. Furthermore, hs-CRP was a negative predictor of serum and salivary MMP-9.     

Prevalence of Antimicrobial Resistant Bacteria from Conjunctival Flora in an Eye Infection Prone Breed (Saint Bernard)

The conjunctival bacterial resident and opportunistic flora of dogs may represent a major source of dissemination of pathogens throughout the environment or to other animals and humans. Nevertheless, contamination with bacteria from external sources is common. In this context, the study of the antimicrobial resistance (AMR) pattern may represent an indicator of multidrug resistant (MDR) strains exchange. The present study was focused on a single predisposed breed—Saint Bernard. The evaluated animals were healthy, but about half had a history of ocular disease/treatment. The swabs collected from conjunctival sacs were evaluated by conventional microbiological cultivation and antimicrobial susceptibility testing (AST). The most prevalent Gram-positive was Staphylococcus spp.; regardless of the history, while Gram-negative was Pseudomonas spp.; exclusively from dogs with a history of ocular disease/treatment. Other identified genera were represented by Bacillus, Streptococcus, Trueperella, Aeromonas and Neisseria. The obtained results suggest a possible association between the presence of mixed flora and a history of ocular disease/treatment. A high AMR was generally observed (90%) in all isolates, especially for kanamycin, doxycycline, chloramphenicol and penicillin. MDR was recorded in Staphylococcus spp. and Pseudomonas spp. This result together with a well-known zoonotic potential may suggest an exchange of these strains within animal human populations and the environment.     

Physicochemical Characterization,Antioxidant Capacity,and Sensory Properties of Murici (Byrsonima crassifolia (L.) Kunth) and Taperebá (Spondias mombin L.) Beverages

Amazonian fruits are excellent sources of bioactive compounds and can be used in beverages to improve the nutritional and sensorial characteristics. The present study aimed to develop a blend of murici (Byrsonima Crassifolia (L.) Kunth) and taperebá (Spondias Mombin L.) through experimental design and investigating the nutritional and sensorial characteristics of fruits and beverages. The murici was highlighted as higher vitamin C content (58.88 mg · 100 g⁻¹) compared to taperebá (25.93 mg · 100 g⁻¹). The murici and taperebá are good sources of total phenolic compounds (taperebá 1304.15 ± 19.14 mgGAE · 100 g⁻¹ and the murici of 307.52 ± 19.73 mg GAE · 100 g⁻¹) and flavonoids (174.87 ± 1.76 μgQE/g and 129.46 ± 10.68 μgQE/g, murici and taperebá, respectively), when compared to other Brazilian fruits. The antioxidant capacity in different methods revealed that the taperebá had a higher average in the results, only in the ORAC method and did not present a significant difference (p > 0.05) in relation to the murici. The beverage development was performed using experimental design 2³, showed through sensory analysis and surface response methodology that murici and high sugar content (between 12.5 and 14.2% of sugar) influenced in sensory acceptance. Our findings indicate that beverages with improved nutrition and a sensory acceptance can be prepared using taperebá and murici fruits.     

Large-scale Monte Carlo study of a realistic lattice model for Ga(1-x)MnxAs

Mn-doped GaAs is studied with a real-space Hamiltonian on an fcc lattice that reproduces the valence bands of undoped GaAs. Large-scale Monte Carlo (MC) simulations on a Cray XT3, using up to a thousand nodes, were needed. Spin-orbit interaction and the random distribution of the Mn ions are considered. The hopping amplitudes are functions of the GaAs Luttinger parameters. At the realistic coupling J approximately 1.2 eV the MC Curie temperature and magnetization curves agree with experiments for x = 8.5% annealed samples. Mn-doped GaSb and GaP are also briefly discussed.