Rheological Measurements and Thermal Characterization of Lamellar Gel Phase Emulsions Developed with Cetearyl Alcohol/Nonionic Ethoxylated Surfactants

The aim of this research was to characterize emulsion systems (ES) containing nonionic ethoxylated surfactants by using rheological, microscopic, and thermogravimetric assays. Three formulations were developed: ES-1: 8.0% (w/w) oleth-20; ES-2: 4.0% (w/w) oleth-20 / 4.0% (w/w) steareth-21; and ES-3: 8.0% (w/w) steareth-21. The systems showed typical non-Newtonian pseudo-plastic behavior. The presence of a lamellar gel phase was observed for all systems, with ES-2 being more pronounced. Through thermogravimetry, the profiles of the three systems were found to be similar, consisting of two main events, the first one being characterized by loss of water and, beyond 110°C, by loss of the oil phase.     

Adsorption and Electrooxidation of Nucleic Acids at Glassy Carbon Electrodes Modified with Multiwalled Carbon Nanotubes Dispersed In Polylysine

We report the advantages of the adsorption and electrooxidation of oligonucleotides and calf‐thymus double stranded DNA (dsDNA) at glassy carbon electrodes (GCE) modified with a dispersion of multiwalled carbon nanotubes (MWCNT) in poly‐L ‐lysine (Plys) (GCE/MWCNT‐Plys). Important enhancement in the guanine oxidation signal was obtained by adsorptive stripping voltammetry (AdSV) due to a most favorable interaction between the negatively charged DNAs and the positively charged Plys that support the MWCNT. The layer of oligo(dG)₁₁ immobilized at GCE/MWCNT‐Plys was successfully used for the selective detection of the hybridization event using oligo(dG)₁₁/oligo(dC)₁₁ as model.     

Adamantane-bearing benzylamines and benzylamides: novel building blocks for supramolecular systems with finely tuned binding properties towards β-cyclodextrin

Novel building blocks for the synthesis of supramolecular components based on adamantane-bearing benzylamines were prepared. The binding properties of these amines and the corresponding acetamides towards β-cyclodextrin (β-CD) were studied using mass spectrometry, NMR spectrometry, isothermal titration calorimetry and semi-empirical calculations. It was found that all of the examined guests predominantly formed 1:1 inclusion complexes in an enthalpy-driven manner with association constants of the order of 10²–10³ M^? 1. Stronger binding to the β-CD cavity was observed for guests with a longer spacer between the adamantane and benzene moieties and/or a 1,4-disubstituted benzene ring.     

Effects of Humidity,Temperature and Bismuth Electrodeposition on Electroanalytical Performances of Nafion‐coated Printed Electrodes for Cd2+ and Pb2+ Detection

The synergistic use of Nafion polymeric membrane and in situ electrodeposited bismuth film is a worthwhile strategy to develop electrochemical sensors for the detection of Cd²⁺ and Pb²⁺. However, Nafion thin films morphological and conductivity properties have a strong dependence on the environmental conditions, such as relative humidity and temperature, while the bismuth in situ electroplating can affect the repeatability of measurements. With the aim to overcome these drawbacks, the effects of the storage environmental conditions were investigated to improve the morphological stability and electroanalytical performances of Nafion film‐based sensor for the detection of Cd²⁺ and Pb²⁺. Nafion‐coated graphite‐based screen‐printed electrodes were stored at different humidity and temperature conditions and characterised by using square wave anodic stripping voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. Significant differences were observed at the varying of humidity conditions, with an enhancement of sensor electrochemical performances at lower humidity. Furthermore, different approaches for bismuth in situ electrodeposition on Nafion‐coated screen‐printed electrodes were compared by using overlap or removal approach. This study disclosed considerable differences in the electrochemical performances and morphology of the resulting bismuth‐sensor, obtaining an enhancement of the working stability for the removal approach.     

Preliminary study for simultaneous detection and quantification of androgenic anabolic steroids using ELISA and pattern recognition techniques

A first step towards the multidetection, identification and quantification of anabolic androgenic steroids by enzyme-linked immunosorbent assay (ELISA) has been performed in this study. This proposal combines multiple competitive ELISA assays with different cross-reactivity profiles and multivariate data analysis techniques. Data have been analyzed by principal component analysis in conjunction with a novel K-nearest line classifier. This proposal allows simultaneous detection of up to four different steroids in the range of concentration from 0.1 to 316.2 nM with a total rate of 90.6% of correct detection, even in the presence of cross-reactivities. A methodology for concentration prediction is also presented with satisfactory results.     

Thermal transformation of a layered multifunctional network into a metal-organic framework based on a polymeric organic linker

The preparation of layered [La(H(3)nmp)] as microcrystalline powders from optimized microwave-assisted synthesis or dynamic hydrothermal synthesis (i.e., with constant rotation of the autoclaves) from the reaction of nitrilotris(methylenephosphonic acid) (H(6)nmp) with LaCl(3)·7H(2)O is reported. Thermogravimetry in conjunction with thermodiffractometry showed that the material undergoes a microcrystal-to-microcrystal phase transformation above 300 °C, being transformed into either a three-dimensional or a two-dimensional network (two models are proposed based on dislocation of molecular units) formulated as [La(L)] (where L(3-) = [-(PO(3)CH(2))(2)(NH)(CH(2)PO(2))O(1/2)-](n)(3n-)). The two crystal structures were solved from ab initio methods based on powder X-ray diffraction data in conjunction with structural information derived from (13)C and (31)P solid-state NMR, electron microscopy (SEM and EDS mapping), FT-IR spectroscopy, thermodiffractometry, and photoluminescence studies. It is shown that upon heating the coordinated H(3)nmp(3-) anionic organic ligand undergoes a polymerization (condensation) reaction to form in situ a novel and unprecedented one-dimensional polymeric organic ligand. The lanthanum oxide layers act, thus, simultaneously as insulating and templating two-dimensional scaffolds. A rationalization of the various steps involved in these transformations is provided for the two models. Photoluminescent materials, isotypical with both the as-prepared ([(La(0.95)Eu(0.05))(H(3)nmp)] and [(La(0.95)Tb(0.05))(H(3)nmp)]) and the calcined ([(La(0.95)Eu(0.05))(L)]) compounds and containing stoichiometric amounts of optically active lanthanide centers, have been prepared and their photoluminescent properties studied in detail. The lifetimes of Eu(3+) vary between 2.04 ± 0.01 and 2.31 ± 0.01 ms (considering both ambient and low-temperature studies). [La(H(3)nmp)] is shown to be an effective heterogeneous catalyst in the ring opening of styrene oxide with methanol or ethanol, producing 2-methoxy-2-phenylethanol or 2-ethoxy-2-phenylethanol, respectively, in quantitative yields in the temperature range 40-70 °C. The material exhibits excellent regioselectivity to the β-alkoxy alcohol products even in the presence of water. Catalyst recycling and leaching tests performed for [La(H(3)nmp)] confirm the heterogeneous nature of the catalytic reaction. Catalytic activity may be attributed to structural defect sites. This assumption is somewhat supported by the much higher catalytic activity of [La(L)] in comparison to [La(H(3)nmp)].     

Behavior of Wild-type and Transfected S2 Cells Cultured in Two Different Media

An animal protein-free medium composed of IPL-41 containing 6 g L^?1 yeastolate ultrafiltrate, 10 g L^?1 glucose, 2 g L^?1 lactose, 5 g L^?1 glutamine, 1% lipid emulsion, and 0.1% Pluronic F-68 was used for producing recombinant proteins in batch mode employing two cell lines, S2AcRVGP2k expressing the G glycoprotein from rabies virus (RVGP) and S2AcHBsAgHy-9C expressing the surface antigen of hepatitis B virus (HBsAg), both obtained from Drosophila melanogaster S2 cells. Growth of wild-type S2 cells was also evaluated in the same medium. Cell behavior in the tested medium was compared to that verified in Sf900 II®. The results show that in shake flasks, S2AcRVGP2k and S2AcHBsAgHy-9C cells reached around 2?×?10⁷ cells mL^?1 in both media. In supplemented IPL-41 and Sf900 II® media, S2AcRVGP2k cells produced 367 ng RVGP mL^?1 and 638 ng RVGP mL^?1, respectively, while S2AcHBsAgHy-9C cells correspondently produced 573 ng HBsAg mL^?1 and 322 ng HBsAg mL^?1 in the mentioned media. In stirred tanks, S2AcRVGP2k cells reached 3?×?10⁷ cells mL^?1 and produced up to 758 ng RVGP mL^?1. In general, glucose was consumed by cells, while lactate and ammonia were produced.     

N-linked peptidoresorc[4]arene-based receptors as noncompetitive inhibitors for α-chymotrypsin

This paper deals with the design, synthesis, and evaluation of a new series of receptors for protein surface recognition. The design of these agents is based around the attachment of four constrained dipeptide chains onto a central resorc[4]arene scaffold. By varying the sequence, nature, and stereochemistry of the chains we prepared anionically functionalized N-linked peptidoresorc[4]arenes 12, 13, and 17 by Pd/C-catalyzed hydrogenation of the corresponding benzyl esters 10, 11, and 16. From this family of receptors we have identified noncompetitive inhibitors of α-chymotrypsin (ChT), which function by binding to the surface of the enzyme in the neighborhood of the active site cleft (K(i) values ranging from 12.4 ± 5.1 μM for free carboxylic acid (+)-12b to 0.76 ± 0.14 μM for benzyl ester (-)-16a). For anionically functionalized receptors 12, 13, and 17 the ChT inhibition is based essentially on electrostatic interaction, and the bound enzyme can be released from the resorcarene surface by increasing the ionic strength, with its activity almost completely restored. For receptors with terminal benzyl ester groups (10 and 16) a hydrophobic network can be suggested.     

Europium(III) Concentration Effect on the Spectroscopic and Photoluminescent Properties of BaMoO4:Eu

BaMoO₄:Eu (BEMO) powders were synthesized by the polymeric precursor method (PPM), heat treated at 800 °C for 2 h in a heating rate of 5 °C/min and characterized by powder X-ray diffraction patterns (XRD), Fourier Transform Infra-Red (FTIR) and Raman spectroscopy, besides room temperature Photoluminescence (PL) measurements. The emission spectra of BEMO samples under excitation of 394 nm present the characteristic Eu³⁺ transitions. The relative intensities of the Eu³⁺ emissions increase as the concentration of this ion increases from 0.01 to 0.075 mol, but the luminescence is drastically quenched for the Ba_0.855Eu_0.145MoO₄ sample. The one exponential decay curves of the Eu^{3+ 5}D₀→⁷F₂ transition, λ _exc = 394 nm and λ _em = 614 nm, provided the decay times of around 0.54 ms for all samples. It was observed a broadening of the Bragg reflections and Raman bands when the Eu⁺³ concentration increases as a consequence of a more disordered material. The presence of MoO₃ and Eu₂Mo₂O₇ as additional phases in the BEMO samples where observed when the Eu³⁺ concentration was 14.5 mol%.