Assessing water-quality data: The relationship between the water quality amelioration of Lake Balaton and the construction of its mitigation wetland

Lakes are sensitive to environmental changes and anthropogenic effects; and Lake Balaton, the largest shallow freshwater lake in Central Europe, is no exception. To protect the lake (primarily Keszthely Bay) against elevated nutrient loads, the Kis–Balaton Water Protection System (KBWPS) was constructed as a mitigation wetland at the mouth of the River Zala, the largest tributary of the lake. This research demonstrates the effect of the KBWPS on Keszthely Bay's oligotrophication processes. The concentration values of KBWPS and Keszthely Bay's measured parameters and their stochastic relations were analyzed by applying cluster- discriminant analysis, Wilks' lambda statistics, confirmatory principal component- (PCA), and input–output analyses to 19 parameters from 14 monitoring stations. First, the sampling sites were clustered for each year, showing that when the runoff in the system was low, Keszthely Bay behaved as a separate entity, while in the years with high runoff it rather displayed a similarity to the wetland area of the KBWPS. Secondly, PCA showed that, from the perspective of stochastic relations, changes in the background processes of Keszthely Bay were observed only after the settling of the KBWPS; and that the runoff in the examined years did not have any significant influence on it. Furthermore, the eutrophication processes moved upstream from Keszthely Bay to the hypertrophic area of KBWPS. This study confirms that the effects of the KBWPS – together with other load reduction measures – had a beneficial effect on the oligotrophication of Lake Balaton.     

Towards a multiplex cereal traceability tool using padlock probe ligation on genomic DNA

Current EU regulations on the protection of products with certain characteristics (geographical indications and designations of origin) aim to ensure fair competition for producers and increased consumers’ trust. Within the European integrated research project TRACE analytical methods are being developed to allow the maintenance of specific regulations for PGIs (products of protected geographical indication) and PDOs (products of designated origin). An example within the project is the PGI wheat variety Farro della Garfagnana. The aim of the research was to develop a method to establish the purity of Farro della Garfagnana DNA in complex cereal mixtures. The combined approach of padlock probe ligation and multiplex microarray detection can identify possible admixtures. One undesired ‘contaminant’ for Farro della Garfagnana is common bread wheat (Triticum aestivum), containing the BBA^uA^uDD genome. Since Farro harbours the BBA^uA^u genome, absence of the D-genome rules out the presence of bread wheat. The current detection limit of this multimethod is at least 2.5% bread wheat in Farro.     

The trajectories of secondary electrons in the scanning electron microscope

Three-dimensional simulations of the trajectories of secondary electrons (SE) in the scanning electron microscope have been performed for plenty of real configurations of the specimen chamber, including all its basic components. The primary purpose was to evaluate the collection efficiency of the Everhart-Thornley detector of SE and to reveal fundamental rules for tailoring the set-ups in which efficient signal acquisition can be expected. Intuitive realizations about the easiness of attracting the SEs towards the biased front grid of the detector have shown themselves likely as false, and all grounded objects in the chamber have been proven to influence the spatial distribution of the signal-extracting field. The role of the magnetic field penetrating from inside the objective lens is shown to play an ambiguous role regarding possible support for the signal collection.     

In Vitro Comparative Study of Solid Lipid and PLGA Nanoparticles Designed to Facilitate Nose-to-Brain Delivery of Insulin

The brain insulin metabolism alteration has been addressed as a pathophysiological factor underlying Alzheimer’s disease (AD). Insulin can be beneficial in AD, but its macro-polypeptide nature negatively influences the chances of reaching the brain. The intranasal (IN) administration of therapeutics in AD suggests improved brain-targeting. Solid lipid nanoparticles (SLNs) and poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) are promising carriers to deliver the IN-administered insulin to the brain due to the enhancement of the drug permeability, which can even be improved by chitosan-coating. In the present study, uncoated and chitosan-coated insulin-loaded SLNs and PLGA NPs were formulated and characterized. The obtained NPs showed desirable physicochemical properties supporting IN applicability. The in vitro investigations revealed increased mucoadhesion, nasal diffusion, and drug release rate of both insulin-loaded nanocarriers over native insulin with the superiority of chitosan-coated SLNs. Cell-line studies on human nasal epithelial and brain endothelial cells proved the safety IN applicability of nanoparticles. Insulin-loaded nanoparticles showed improved insulin permeability through the nasal mucosa, which was promoted by chitosan-coating. However, native insulin exceeded the blood-brain barrier (BBB) permeation compared with nanoparticulate formulations. Encapsulating insulin into chitosan-coated NPs can be beneficial for ensuring structural stability, enhancing nasal absorption, followed by sustained drug release.     

General conditions for online estimation and optimization of reliability characteristics

A novel approach to estimate reliability properties of systems or components individually during operation is presented. It is distinguished between slow and fast reliability states based on an equivalent system representation. Conditions for their observability and control are given and objectives for optimal reliability-based control are discussed in general.     

HPLC–ESI-MS investigation of tyrosol and hydroxytyrosol oxidation products in virgin olive oil

The aim of this research is the characterisation of the oxidation products of several hydrophilic phenols of virgin olive oil (VOO), such as hydroxytyrosol (3,4-DHPEA) and tyrosol (p-HPEA) and, their identification in the product during storage. This work is aimed at finding analytical indicators that can be used both as molecular markers of VOO “freshness” and for the evaluation of the shelf life of the product itself. Two oxidation systems were examined for the oxidation of p-HPEA and 3,4-DHPEA: enzymatic oxidation and Fenton oxidation. Reaction products were different for the two systems and were identified as quinones, dimers, and acids. During the autoxidation process, Fenton reaction oxidation products, but not enzymatic oxidation products, were found in VOO.     

Influence of carbohydrates on stability of papain in aqueous tetrahydrofuran mixture

BACKGROUND: The use of enzymes in organic solvents has extended the scale of their practical applications. Papain has been widely used in chemical syntheses because of its broad substrate specificity. The aim of the present study was to improve the stability of papain in aqueous tetrahydrofuran (THF) by using different saccharides. The effects of these carbohydrates on the structure of papain were followed by means of circular dichroism (CD) and fluorescence spectroscopic measurements. RESULTS: In contrast with most organic solvents, 60% (i.e. 600 mL L^?1) THF practically inactivated the enzyme within 30 min. Sugars protected papain from THF‐induced inactivation in the sequence D ‐ribose > D ‐fructose > D ‐glucose > D ‐saccharose > D ‐raffinose. Ribose at 1.6 mol L^?1 proved the most effective stabiliser: in 60% THF in the presence of ribose, papain preserved about 55% of its initial activity after 2 h. Fluorescence and near‐UV CD spectroscopic measurements revealed local changes in the papain conformation. With decrease in the free amino group content of the enzyme, protein‐carbohydrate interactions (Schiff base formation) were detected. CONCLUSION: These results demonstrate that the catalytic activity and stability of papain may be increased in aqueous THF by using different carbohydrates, when a more compact structure of the enzyme is formed. Copyright © 2008 Society of Chemical Industry