Comparison of Fenton's oxidation and ozonation for removal of estrogens

This study compares efficiency of Fenton's oxidation and ozonation of 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) as two possible processes for removal of estrogens from aqueous solutions. The effectiveness of Fenton's oxidative removal was studied at different ratios of reagents Fe2+:H2O2 (1:0.5; 1:10; 1:20; 1:33), where with some molar ratios up to 100% removal of E2 and EE2 was achieved in the first few minutes of reaction. The best molar ratio for E2 (17beta-estradiol) removal was 1:33, while in the case of EE2 the most efficient one was 1:20 ratio. Ozonation was much faster, because complete removal of estrogens was achieved in 30 seconds (pH approximately eaqual 6), but the time of ozonation was extended up to 60 minutes trying to decompose formed by-products, expressing estrogenic activity, detected by YES (Yeast Estrogen Screening) assay. The obtained results showed that the removal efficiency of estrogens from waters should be assessed by a combination of chemical analyses and bioassay.     

Protus 2.0: Ontology-based semantic recommendation in programming tutoring system

With the development of the Semantic web the use of ontologies as a formalism to describe knowledge and information in a way that can be shared on the web is becoming common. The explicit conceptualization of system components in a form of ontology facilitates knowledge sharing, knowledge reuse, communication and collaboration and construction of knowledge rich and intensive systems. Semantic web provides huge potential and opportunities for developing the next generation of e-learning systems. In previous work, we presented tutoring system named Protus (PRogramming TUtoring System) that is used for learning the essence of Java programming language. It uses principles of learning style identification and content recommendation for course personalization. This paper presents new approach to perform effective personalization highly based on Semantic web technologies performed in new version of the system, named Protus 2.0. This comprises the use of an ontology and adaptation rules for knowledge representation and inference engines for reasoning. Functionality, structure and implementation of a Protus 2.0 ontology as well as syntax of SWRL rules implemented for on-the-fly personalization will be presented in this paper.     

Automatic determination of synergies by radial basis function artificial neural networks for the control of a neural prosthesis.

This paper describes an automatic method for synthesizing the control for a neural prosthesis (NP) that could augment elbow flexion/extension and forearm pronation/supination in persons with hemiplegia. The basis for the control was a synergistic model of reaching and grasping that uses temporal and spatial synergies between the arm and body segments. The synergies were determined from the movement data measured in nondisabled persons during the performance of functional tasks. The work space was divided into six zones: distance (two attributes) and laterality (three attributes). Radial basis function artificial neural networks (RBF ANN) were used to determine synergies. Sets of RBF ANN characterized with good generalization were selected as control laws for elbow flexion/extension and forearm pronation/supination. The validation was performed for three categories: inter-subject, distance, and laterality generalization. For all of the defined spatial synergies, the correlation was high for inter-subject and distance, yet low for the laterality scenario. This suggests the necessity for implementing different maps for different directions, but the same maps for different distances. The natural movements of the upper arm then drive the lower arm (elbow flexion/extension and forearm pronation/supination) in a way that is very well suited for the administration of functional electrical therapy (FET) in persons with hemiplegia soon after the onset of impairment.     

Environmental Factors That Affect Parathyroid Hormone and Calcitonin Levels

Calciotropic hormones, parathyroid hormone (PTH) and calcitonin are involved in the regulation of bone mineral metabolism and maintenance of calcium and phosphate homeostasis in the body. Therefore, an understanding of environmental and genetic factors influencing PTH and calcitonin levels is crucial. Genetic factors are estimated to account for 60% of variations in PTH levels, while the genetic background of interindividual calcitonin variations has not yet been studied. In this review, we analyzed the literature discussing the influence of environmental factors (lifestyle factors and pollutants) on PTH and calcitonin levels. Among lifestyle factors, smoking, body mass index (BMI), diet, alcohol, and exercise were analyzed; among pollutants, heavy metals and chemicals were analyzed. Lifestyle factors that showed the clearest association with PTH levels were smoking, BMI, exercise, and micronutrients taken from the diet (vitamin D and calcium). Smoking, vitamin D, and calcium intake led to a decrease in PTH levels, while higher BMI and exercise led to an increase in PTH levels. In terms of pollutants, exposure to cadmium led to a decrease in PTH levels, while exposure to lead increased PTH levels. Several studies have investigated the effect of chemicals on PTH levels in humans. Compared to PTH studies, a smaller number of studies analyzed the influence of environmental factors on calcitonin levels, which gives great variability in results. Only a few studies have analyzed the influence of pollutants on calcitonin levels in humans. The lifestyle factor with the clearest relationship with calcitonin was smoking (smokers had increased calcitonin levels). Given the importance of PTH and calcitonin in maintaining calcium and phosphate homeostasis and bone mineral metabolism, additional studies on the influence of environmental factors that could affect PTH and calcitonin levels are crucial.     

Determination of <Emphasis Type="Italic">Bacillus cereus</Emphasis> Emetic Toxin in Food Products by Means of LC–MS²

Cereulide is the heat-stable toxin produced by certain strains of Bacillus cereus. It is the main virulence factor of emetic B. cereus strains, which causes the emetic food poisoning syndrome, including rare fatal cases of food intoxications. Due to presumably low intoxication doses, a sensitive, specific, and robust technique is needed for its detection. In 2002, a LC–MS method was developed which allowed absolute quantification of cereulide using valinomycin as standard. This study describes the validation, according to the Commission Decision 2002/657/EC, of the LC–MS2 method, a tandem mass spectrometry technique, which guarantees lower detection limit and higher specificity. The LC–MS2 method, calibrated with valinomycin, was validated in rice and tested on various matrices (i.e., red beans, spices, and chili con carne) containing cereulide. The process combines a simple extraction step from the food matrix followed by LC–MS2 analysis and detection by ion trap mass spectrometer. The detection limit for cereulide in rice was 0.5 ng eq/g, which is 20 to 2,500 times lower than currently understood intoxicative doses between 10 and 1.280 ng/g previously reported for cereulide. The validated method was specific, sensitive, repeatable, and reproducible with recoveries ranging from 77% to 101%.     

Phenolic profile and antioxidant capacities of dried red currant from Serbia, extracted with different solvent

The antioxidant capacity and the phenolic content of 3 dried red currant samples from different geographical regions were studied. Three solvent systems were used (methanol, ethanol, and acetone) at the same concentrations (70%) and with 100% deionized water in presence 0.1% HCl. The antioxidant capacity of the dried fruit extracts was evaluated using DPPH radical scavenging assays. The efficiency of the solvents used to extract phenols from the 3 dried red currant samples varied considerably. The polyphenol content of the dried red currant samples was 3.26 to 12.68 mg gallic acid equivalent/g dried fruit. The high phenolic content was significantly correlated with the high antioxidant capacity. The following compounds were identified and quantified using HPLC with photodiode-array detection: 3 anthocyanins, 2 flavonols, 2 flavan-3-ols, and 3 hydroxycinnamic acids in all samples. Generally, red currant fruits are a rich source of phenolics, which shows an evident antioxidant capacity.     

Elemental Composition of Various Sour Cherry and Table Grape Cultivars Using Inductively Coupled Plasma Atomic Emission Spectrometry Method (ICP-OES)

Three sour cherry and three table grape cultivars were analyzed using inductively coupled plasma optical emission spectrometry. The elements: Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Cr, Cd, Co, Pb, and Ni were detected in all samples; four elements are very abundant (K, Na, Ca, and Mg), and four are not abundant (Cu, Fe, Mn, and Zn). Five of them are trace elements (Cr, Cd, Co, Pb, and Ni) at <0.1 mg/kg. Among the 13 elements analyzed, potassium was the most abundant element distributed throughout all categories of fruits. Iron was the predominant minor element constituents. Manganese concentration was the highest in table grape cultivars. The accuracy of the results was evaluated by spike recovery tests. Analysis of variance was used to establish the metals with significant difference in mean content between the cultivars from sour cherries and between table grapes. Principal component analysis was used to evaluate the distribution of metals.     

Application of Twisselmann extraction, SPME, and GC-MS to assess input sources for organophosphate esters into soil

Although the ubiquitous distribution of organophosphate esters (OPEs) in the environment has been documented very thoroughly, data on their occurrence in soil is so far sparse. In this study, an analytical method was developed to determine six OPEs in soil. The method consists of a combination of Twisselmann extraction and solid-phase microextraction (SPME), followed by gas chromatography-mass spectrometry (GC-MS). To develop the method, spiked soil was extracted using a Twisselmann extractor after freeze-drying. The extract was evaporated to dryness, redissolved, and filtered. A volume of 7 mL was then analyzed by SPME, followed by GC-MS. The effects of different parameters on analyte recoveries during sample preparation, e.g., solvent for Twisselmann extraction, solvent for redissolving the extract, addition of copper, and filtration of the extract, were systematically investigated. Under optimum conditions, 10 g soil samples were extracted using toluene, and the extract was redissolved in methanol/water (1:14) and filtered. It was not necessary to add copper. For TnBP, TBEP, TCPP, and TCEP, recoveries ranged from 77.0% to 89.6%. Those for TPP and TDCP were much lower, at 31.5% and 42.0%, respectively (addition level 22.9-45.8 ng g(-1)). The variability of recoveries under these conditions was between 0.3 and 16.2% (n = 3). Limits of detection (LOD) were 0.002-3 ng g(-1). When ultrasonication was used in place of Twisselmann extraction in the developed method, recoveries were three to four times lower (27.4% to 30.6%), but the variability of recoveries was below 3% (n = 3). The method was applied to quantify OPEs in soil collected from the university campus in Osnabrueck (Germany). Average concentrations (n = 6) in soil samples ranged from 1.23 ng g(-1) to 4.96 ng g(-1) (dry weight) for TCPP, TPP, and TCEP. The results demonstrate for the first time that atmospheric deposition leads to soil contamination by OPEs.     

The influence of genotypic variation in protein composition on emulsifying properties of soy proteins

This study describes the relationship between the emulsifying properties of soybean proteins and their composition, i.e., glycinin (11S) and β-conglycinin (7S). Twelve investigated soybean genotypes showed significant differences in storage protein composition. The β-conglycinin concentration positively correlated with extractable soluble protein content, which was positively correlated with protein extractability. These data suggest that the level of β-conglycinin has a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the 11S∶7S ratio and strongly and negatively correlated with the concentration of β-conglycinin. The emulsion stability index (ESI) showed a moderate positive correlation with the monomeric form of glycinin and a strong positive correlation with the ratio of the monomeric to dimeric form of glycinin. No association was evident between ESI and EAI. Also, no relationship was found between ESI or EAI and extractability. Based on these data, it appears that the 11S∶7S ratio strongly reflects the ability of soybean proteins to form emulsions, whereas the ratio of the two different forms of glycinin may be crucial factors for the stability of soybean protein emulsions. Thus, understanding the relationship between protein composition and functionality could be useful for further improvement of functional behavior of soy proteins in food systems.     

Synthesis and Characterization of Rutile TiO2 Nanopowders Doped with Iron Ions

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5–7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO₂ into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence.