In Situ Incorporation of Praziquantel in Polymer Microparticles through Suspension Polymerization for Treatment of Schistosomiasis

Schistosomiasis is one of the major public health problems worldwide. Even though this is a common illness among preschool children in poor countries, treatment is carried out mainly through the administration of praziquantel tablets, which has some disadvantages, such as the strong bitter taste. As an alternative to overcome this problem, the development of new encapsulated praziquantel formulations is demanded. For this reason, suspension polymerizations are carried out for the in situ encapsulation of praziquantel into polymer microparticles, using methyl methacrylate (MMA) and cationic compounds (diethylaminoethyl methacrylate, DEAEMA, and dimethylaminoethyl methacrylate, DMAEMA) as comonomers. This technique allows for the preparation of polymer microparticles with high encapsulation efficiencies (>90%) with characteristic sizes ranging from 0.5 to 1500 µm. Drug release profiles show that praziquantel is released from poly(methyl methacrylate) microparticles slowly due to the existence of strong diffusional resistance. On the other hand, the addition of cationic comonomers renders polymer particles sensitive to pH variations, allowing for faster release of praziquantel in acidic environments, as found in the stomach.     

The Generalized Clifford-Gegenbauer Polynomials Revisited

By applying a method introduced by De Bie and Sommen in Clifford superanalysis, the orthogonality relations of the generalized Clifford–Gegenbauer polynomials of wavelet analysis are extended. Moreover, this new approach allows for proving new important properties of these polynomials, such as an annihilation equation, a differential equation and an expression in terms of the Jacobi polynomials on the real line. This paper is dedicated to the memory of our friend and colleague Jarolim Bureš     

Explicit portfolio for unit-linked life insurance contracts with surrender option

Introducing a surrender option in unit-linked life insurance contracts leads to a dependence between the surrender time and the financial market. [J. Barbarin, Risk minimizing strategies for life insurance contracts with surrender option, Tech. rep., University of Louvain-La-Neuve, 2007] used a lot of concepts from credit risk to describe the surrender time in order to hedge such types of contracts. The basic assumption made by Barbarin is that the surrender time is not a stopping time with respect to the financial market.The goal of this article is to make the hedging strategies more explicit by introducing concrete processes for the risky asset and by restricting the hazard process to an absolutely continuous process.First, we assume that the risky asset follows a geometric Brownian motion. This extends the theory of [T. Møller, Risk-minimizing hedging strategies for insurance payment processes, Finance and Stochastics 5 (2001) 419–446], in that the random times of payment are not independent of the financial market. Second, the risky asset follows a Lévy process.For both cases, we assume the payment process contains a continuous payment stream until surrender or maturity and a payment at surrender or at maturity, whichever comes first.     

Screening approach for chiral separation of pharmaceuticals IV. Polar organic solvent chromatography

The aim of this work is to determine generic screening conditions and an initial simple separation strategy allowing the rapid separation of drug enantiomers in polar organic solvent chromatography (POSC). Four cellulose/amylose-based stationary phases were investigated in detail using two mobile phase basis solvents commonly applied in this mode, i.e. acetonitrile and methanol. Polar mode is interesting for use in purification of enantiomers. In a first step, the parameters potentially influencing the separation, such as addition of an alcohol to the polar organic solvent or the type of mobile phase additive(s), were examined by means of experimental designs. Afterwards, the factors found most important are investigated in more detail. Results showed that the cellulose- and amylose-based stationary phases have very broad and complementary enantiorecognition abilities in the POSC mode. The type of organic solvent for the mobile phase appeared to have a dramatic influence on the quality of the separation. Based on the results, a screening strategy was proposed. Enantioseparation was observed in more than 85% of the tested compounds and analysis times of last eluted peak were usually below 10 min.     

Determination of hydroxycinnamic acids and volatile phenols in wort and beer by isocratic high-performance liquid chromatography using electrochemical detection

The suitability of a simple and rapid isocratic RP-HPLC method with amperometric electrochemical detection for the simultaneous detection and quantification of hydroxycinnamic acids and their corresponding aroma-active volatile phenols in wort and beer is reported. The technique gives good specificity and sensitivity, and can therefore be used for routine monitoring of hydroxycinnamic acids in wort and the development of volatile phenolic flavour compounds during the beer production process and subsequent conservation.     

Precision study on capillary electrophoresis methods for metacycline

A CE method for metacycline (MTC) determination was investigated in an inter-laboratory experiment. Many problems were encountered in this study, most of which were related to the transfer of the method to different CE equipment. The reported problems could be classified into different categories: problems related to the precision, to the parameters in the protocol, and to the MTC peak shape. As the peak shape problem was partially responsible for the poor precision, a new CE method was developed in order to obtain a good MTC peak shape on all equipment. The precision of this new method for MTC determination was examined in an intermediate precision study, where the influence of the factors "time" and "equipment" was investigated. Although the new method could be transferred to different instruments, the precision remained poor mainly due to the contributions of the between-replicate and the between-injection variances.     

Phase-Field Modelling in Extractive Metallurgy

The phase-field method has already proven its usefulness to simulate microstructural evolution for several applications, e.g., during solidification, solid-state phase transformations, fracture, etc. This wide variety of applications follows from its diffuse-interface approach. Moreover, it is straightforward to take different driving forces into account. The purpose of this paper is to give an introduction to the phase-field modelling technique with particular attention for models describing phenomena important in extractive metallurgy. The concept of diffuse interfaces, the phase-field variables, the thermodynamic driving force for microstructure evolution and the phase-field equations are discussed. Some of the possibilities to solve the equations describing microstructural evolution are also described, followed by possibilities to make the phase-field models quantitative and the phase-field modelling of the microstructural phenomena important in extractive metallurgy, i.e., multiphase field models. Finally, this paper illustrates how the phase-field method can be applied to simulate several processes taking place in extractive metallurgy and how the models can contribute to the further development or improvement of these processes.