Determination of ciclopirox olamine in pharmaceutical products by capillary electrophoresis with capacitively coupled contactless conductivity detection

This paper describes the determination of ciclopirox olamine in pharmaceutical formulations using capillary electrophoresis with capacitively coupled contactless conductivity detection. In an alkaline medium, ciclopirox olamine is converted into an anionic species and its detection is possible in capillary electrophoresis with capacitively coupled contactless conductivity detection without an electroosmotic flow modifier, because it is a low-mobility species. A linear working range from 2.64 to 264 μg/mL in sodium hydroxide electrolyte as well as low detection limit (0.39 μg/mL) and a good repeatability (RSD = 3.4% for 264 μg/mL ciclopirox solution (n = 10)) were achieved. It was also possible to determine olamine in its cationic form when acetic acid was used as the electrolyte solution. The results obtained include a linear range from 26.4 to 184.8 μg/mL and a detection limit of 2.6 μg/mL olamine. The proposed methods were applied to the analysis of commercial pharmaceutical products and the results were compared with the values indicated by the manufacturer as well as those obtained using a titrimetric method recommended by American Pharmacopoeia.     

Integrated Process Production and Extraction of the Fibrinolytic Protease from Bacillus sp. UFPEDA 485

Fibrinolytic proteases are enzymes that degrade fibrin; these enzymes are a promising alternative for thrombolytic therapy, and microorganisms produce them. The aim of this study was to evaluate the optimum conditions for the integrated production and purification of fibrinolytic protease from Bacillus sp. UFPEDA 485. Extractive fermentation was carried out in a culture medium containing soybean flour and by adding polyethylene glycol (PEG) and Na₂SO₄ according to a 2³ experimental design. In all assays, the enzyme preferentially partitioned to the bottom phase (K?<?1), with an optimum activity of 835 U ml^?1 in the bottom phase (salt-rich phase). The best conditions for extractive fermentation were obtained with 18 % PEG 8000 and 13 % Na₂SO₄. Characterization showed that it is a metalloprotease, as a strong inhibition—residual activity of 3.13 %—occurred in the presence of ethylenediaminetetraacetic acid. It was also observed that enzymatic activity was stimulated in the presence of ions: CaCl₂ (440 %), MgCl₂ (440 %), FeSO₄ (268 %), and KCl (268 %). The obtained results indicate that the use of a low-cost substrate and the integration of fermentation with an aqueous two-phase system extraction may be an interesting alternative for the production of fibrinolytic protease.     

Quantitative analysis of biodiesel in blends of biodiesel and conventional diesel by comprehensive two-dimensional gas chromatography and multivariate curve resolution

In this paper, a method to determine the composition of blends of biodiesel with mineral diesel (BXX) by multivariate curve resolution with Alternating Least Squares (MRC-ALS) combined to comprehensive two-dimensional gas chromatography with Flame Ionization Detection (GC × GC-FID) is presented. Chromatographic profiles of BXX blends produced with biodiesels from different sources were used as input data. An initial evaluation carried out after multiway principal component analysis (MPCA) was used to reveal regions of the chromatograms were the signal was likely to be dependent on the concentration of biodiesel, regardless its vegetable source. After this preliminary step MCR-ALS modeling was carried out only using relevant parts of the chromatograms. The resulting procedure was able to predict accurately the concentration of biodiesel in the BXX samples regardless of its origin.     

First X-rays from a novel full-scale superconducting undulator at ANKA: Higher magnetic peak field than cryogenic permanent magnet devices

The ANKA Synchrotron Radiation Facility at KIT and Babcock Noell GmbH (BNG) are pursuing a Research & Development program on superconducting undulators (SCUs). The collaboration focuses on conduction-cooled SCUs with NbTi superconductor coils and a variable vacuum gap. Since SCUs can reach higher magnetic peak fields than permanent magnet in-vacuum insertion devices, including cryogenic ones (for the same gap and period length), they have the potential to increase the spectral range, brilliance and flux of existing state-of-the-art devices.     

Increased Sensitivity of Ascorbate Detection by Mediated Oxidation in Confined Electrochemical Cells

In this work, the EC’ mechanism involving ascorbate (AA⁻) and the oxidized form of ferrocenemethanol (FcMeOH) was explored as an analytical strategy to monitor AA⁻ at low concentration levels. The feasibility of this approach was investigated at different mass transport regimes utilizing macro- (glassy carbon) and ultramicroelectrodes (5 μm radius carbon disk). Cyclic voltammograms (CV) were recorded in acetate buffer solution (pH 3.7) using a glassy carbon electrode, and an expressive increase in the anodic peak current (and decrease in the cathodic peak) was noticed in the CV in a solution containing both FcMeOH and ascorbate, confirming the presence of an electrocatalytic process (EC’). The current increase was more pronounced when the reactants and products were confined in a thin solution layer, which was created by approaching an ultramicroelectrode close to an insulator surface. At optimized experimental conditions, a correlation between ascorbate concentration and the steady-state current measured at the ultramicroelectrode was established, allowing the development of an analytical method for ascorbate detection in the micromolar range. The proposed approach was used to quantify ascorbate in a commercial juice sample.     

Temperature dependence on phase evolution in the BaTiO3 polytypes studied using ab initio calculations

Identifying the forces that drive a temperature-induced phase transition is always challenging in the prospect of the first-principles methods. Herein, we perform a first-principles study of the temperature effects on structural, energetic, electronic, and vibrational properties of four BaTiO₃ polymorphs using quasi-harmonic approximations. Study of the stability between these four phases, which we break into contributions arising from the vibration of the lattice, electronic structure, and volume expansion/contraction, is helpful to confirm the sequence of phase transitions as cubic → tetragonal → orthorhombic → rhombohedral, as well as its transition temperatures. A general mechanism was proposed based on the combination between structural distortions at [TiO₆] clusters, vibrational characteristics, and electronic structure. These findings confirm the power of quasi-harmonic approximations to disclose the main fingerprints associated with both thermic and mechanical phase transitions, serving as a guide for further theoretical studies.     

Synthesis,characterization and in vitro antimicrobial prospecting of silver-doped ceria

Journal of Thermal Analysis and Calorimetry - In this work, Ag-doped CeO2 samples containing 0.5&nbsp;mol% Ag+ were successfully synthesized by the polymeric precursor method and then calcined...     

Experimental and theoretical study of the photophysics and structures of europium cryptates incorporating 3,3'-bi-isoquinoline-2,2'-dioxide.

A detailed photophysical study of [Eu within (biqO2.2.2)(CF3SO3)](CF3SO3)2. CH3CN.H2O (Eu within 1) and two other types of cryptates incorporating three 3,3'-biisoquinoline-2,2'-dioxide units has been performed. Structural crystallographic data of Eu within 1, electronic structure calculations and theoretical models were used to obtain the intramolecular energy transfer rates and the appropriate set of rate equations, which was solved numerically. Quantum yields and decay lifetimes were obtained from these results and compared to the experimental data. The role of the ligand-to-metal charge transfer (LMCT) states was ascertained. A theoretical ligand field and intensity analysis was carried out and the results agree very well with the emission spectra. The molecular structures of the lanthanide cryptates were successfully modelled by the YIII ion using the restricted Hartree-Fock (RHF) method, with the advantage of dealing with closed-shell systems. These molecular structures were used to explain the drastic differences in the photophysics of the three EuIII cryptates.     

Toward Improving the Mathematics Preparation of Elementary Preservice Teachers

Research suggests the importance of mathematics knowledge for teaching (MKT) for enabling elementary school teachers to effectively teach mathematics. MKT involves both mathematical content knowledge (M‐CK) and mathematical pedagogical content knowledge (M‐PCK). However, there is no consensus on how best to prepare elementary preservice teachers (PSTs) to achieve M‐CK and M‐PCK. This study builds on research related to MKT by investigating influences of mathematics content courses designed specifically for elementary PSTs (IMPACT courses—Impact of Mathematics Pedagogy and Content on Teaching) on their attitudes (i.e., confidence and motivation) toward M‐CK and M‐PCK. Results suggest that the PSTs who participated in these IMPACT courses not only acquired high levels of confidence and motivation toward M‐CK, but also showed significant and greater gains in attitudes toward M‐PCK, after taking the required mathematics methods course, than their counterparts. Further, the findings suggest that these IMPACT courses provided a mathematical foundation that allowed the PSTs to engage in mathematics teaching methods better than those PSTs who did not have such a foundation. These results suggest potential course experiences that may enhance M‐CK and M‐PCK for elementary PSTs.