Preparation and characterization of β‐cyclodextrin‐linked chitosan microparticles

Hydrophobically modified chitosan containing β‐cyclodextrin (CD) units was synthesized by using tosylated β‐CD. The final product was characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis and TGA, and rheometry. The polymer bearing β‐CD moieties was used to obtain crosslinked microparticles by spray‐drying which could then be used in a controlled release system for drugs. FTIR confirmed the formation of an amide linkage between cyclodextrin and chitosan. As fluorescence spectroscopy demonstrated, hydrophobic microenvironments were formed by chitosan bearing cyclodextrin in solution at lower concentrations than for chitosan. Rheometry and FTIR showed the crosslinking of the new polymer using genipin, a molecule of natural origin. Microspheres (MS) obtained by spray‐drying showed narrow size distribution when β‐CD was grafted onto chitosan and ξ‐potential of MS was slightly lower although it remained positive. In conclusion, β‐CD linked chitosan polymer can be considered as a very promising controlled drug delivery system for drugs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Forecasting of Hydrographs to Simulate Long Term Recharge From Rivers in Numerical Models of Mining Reservoirs; Application to A Coal Mine in NW Spain

Although the natural permeability of rocks in the Asturian Central Coal Basin (NW Spain) is generally low, intensive mining activities over many decades has given rise to fracture flow paths that are far more permeable than those associated with the natural lithology. Abandoned and flooded mining works set up artificial ‘pseudo‐karst’ aquifers, which can act as underground reservoirs, with many potential applications. In particular, a mining reservoir shaped by two connected mining shafts within the River Turón basin has been studied. A runoff model was used to produce accurate simulations of streamflow in three different gauging stations during a monitored period of 2 years. The purpose was to use this model in the forecast situation, in order to predict long‐term situations in a hydrogeological FEFLOW model. It was necessary to develop depletion curves for each gauging station based on the available daily effective rainfall and measured flow data, as well as the knowledge of the basin characteristics. The resulting simulated hydrographs were very similar to the measured hydrographs during the monitored period, so the adequate adjusting allows input of the flow for forecast purposes. The model produced forecast hydrographs that had a r = 0.8 and difference in annual volume ranging from 1.6% to 5%. The defined model was applied to a rainfall data set of 30 years, and the average recharge from the river to the mining reservoir could be adequately estimated. The method developed needs to be refined and tested on additional years, but the approach appears to be applicable to operational runoff forecasting for numerical models input data. Copyright © 2015 John Wiley & Sons, Ltd.     

Optimization of Sesame Oil Extraction by Screw-Pressing at Low Temperature

Box-Behnken designs were used to optimize a process for sesame oil extraction by screw-pressing at low temperature (50 °C). Experimental designs included seed moisture content (SMC), pressing speed (PS), and restriction die (RD) as the main processing parameters. Extractions at pilot plant scale showed a peak in oil recovery (OR, 71.1 ± 2.80%) at 12.3% SMC, 4 mm RD, and 20 rpm PS. Theoretical models were scanned against experimental data in order to scale up the proposed oil extraction process to industrial scale. A fitted model for OR showed a maximum predicted value similar to the highest experimental value (74.4 ± 1.23%) under the following conditions: 8.03% SMC, 10 mm RD, and 20 rpm PS. Chemical quality parameters of oils obtained at both pilot and industrial scales were in the ranges stated in Codex (FAO/WHO) standards for non-refined sesame oil.     

Coordinating control of production-inventory systems

In most cases real world subsystems for inventory and production control are designed according to very elementary control principles. In order to control the total system, some kind of coordinating control of the subsystems is needed. The approach pursued in this paper is to control the over-all-system by varying different control-parameters of the subsystems. The control system is therefore regarded as a two-level hierarchical system. Coordinating control is carried out with the aid of simple dynamic models based on aggregate terms. Problems concerning the identification of inventory-dynamics ore highlighted. In order to show how the models developed can be used efficiently for coordinating the control of an integrated production-inventory system, a simple control principle is applied to a simulated system.     

Automatic word naming recognition for an on-line aphasia treatment system

One of the most common effects among aphasia patients is the difficulty to recall names or words. Typically, word retrieval problems can be treated through word naming therapeutic exercises. In fact, the frequency and the intensity of speech therapy are key factors in the recovery of lost communication functionalities. In this sense, speech and language technology can have a relevant contribution in the development of automatic therapy methods. In this work, we present an on-line system designed to behave as a virtual therapist incorporating automatic speech recognition technology that permits aphasia patients to perform word naming training exercises. We focus on the study of the automatic word naming detector module and on its utility for both global evaluation and treatment. For that purpose, a database consisting of word naming therapy sessions of aphasic Portuguese native speakers has been collected. In spite of the different patient characteristics and speech quality conditions of the collected data, encouraging results have been obtained thanks to a calibration method that makes use of the patients’ word naming ability to automatically adapt to the patients’ speech particularities.     

Liquid chromatographic determination of caffeine and adrenergic stimulants in food supplements sold in Brazilian e-commerce for weight loss and physical fitness

Methyl-xanthines and adrenergic stimulants, such as caffeine and synephrine, are commonly added to food supplements due to their stimulating and thermogenic effects. In addition, the abusive consumption of food supplements with ergogenic and aesthetic purposes has been observed worldwide. This work describes the study of caffeine, p-synephrine, hordenine, octopamine, tyramine, ephedrine and salicin as stimulants in dietary supplements marketed in Brazil for weight loss and physical fitness claims. A total of 94 different products were acquired from 30 Brazilian websites. Thus, the sampling of marketed supplements was performed in virtual commerce (e-commerce) with claims of weight loss, appetite reduction, fat burning and metabolism acceleration. The developed analytical method involved the separation of the stimulants by HPLC with diode array detection (HPLC-DAD) by using a gradient elution of flow rate (0.7–2.5 ml min^?1) and mobile phase composition (0.1% H₃PO₄/methanol). The validated method was applied to the study of 46 dietary supplements. Caffeine, p-synephrine and ephedrine were found to be present as stimulants in 52% of the studied samples marketed as encapsulated or bulk forms. Caffeine was found to be present in concentrations that represent doses from 25.0 to 1476.7 mg day^–1. Synephrine was found in concentrations that represent doses from 59.1 to 127.0 mg day^–1. Ephedrine was found to be associated with caffeine in one formulation at a concentration representing a 26.1 mg day^–1 dosage.