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Thessaloniki, Greece

The Alexander Technological Educational Institute of Thessaloniki , is a higher education public institute, part of the Greek tertiary education system, specialized on applied science. The institute has three campuses. The main campus is located 15 km outside the city of Thessaloniki in Sindos, the second campus is in the nearby city of Kilkis and the last campus is in Nea Moudania. Wikipedia.

Rigas P.G.,Alexander Technological Educational Institute of Thessaloniki
Analytical and Bioanalytical Chemistry

Amino acid analysis (AAA) has always presented an analytical challenge in terms of sample preparation, separation, and detection. Because of the vast number of amino acids, various separation methods have been applied taking into consideration the large differences in their chemical structures, which span from nonpolar to highly polar side chains. Numerous separation methods have been developed in the past 60 years, and impressive achievements have been made in the fields of separation, derivatization, and detection of amino acids (AAs). Among the separation methods, liquid chromatography (LC) prevailed in the AAA field using either pre-column or post-column labeling techniques in order to improve either separation of AAs or selectivity and sensitivity of AAA. Of the two approaches, the post-column technique is a more rugged and reproducible method and provides excellent AAs separation relatively free from interferences. This review considers current separations combined with post-column labeling techniques for AAA, comparison with the pre-column methods, and the strategies used to develop effective post-column methodology. The focus of the article is on LC methods coupled with post-column labeling techniques and studying the reactions to achieve optimum post-column derivatization (PCD) conditions in order to increase sensitivity and selectivity using various types of detectors (UV-Vis, fluorescence, electrochemical etc.) and illustrating the versatility of the PCD methods for practical analysis. [Figure not available: see fulltext.] © 2013 Springer-Verlag Berlin Heidelberg. Source

Panagopoulos G.,Alexander Technological Educational Institute of Thessaloniki
Environmental Earth Sciences

Karst aquifers can have a complex flow as a result of the formation of large conduits from dissolution features. As a result, a three-dimensional finite-difference groundwater flow model (equivalent porous media) may not apply as the dual porosity nature of karst features and the effects of turbulent flow cannot be directly simulated. Statistical analysis of karst hydrographs of the Trifilia aquifer in Greece showed the existence of a slightly karstified mass with high primary porosity that regulates the flow. An equivalent porous media model was developed to simulate the Trifilia karst aquifer using MODFLOW. Steady state and transient state calibration gave encouraging results for the equivalent porous media approach, which does not consider pipe flow or turbulence. Detailed hydrogeological research conducted in the area helped define the aquifer hydraulic conductivity zones and extent; and flux to/from the aquifer. Only hydraulic conductivity and specific yield were adjusted during calibration, as the flux to/from the system was considered known and applied as boundary conditions. Small mean absolute and RMS piezometric head error of the model under both steady and transient state conditions were achieved. © 2012 Springer-Verlag. Source

Rigas P.G.,Alexander Technological Educational Institute of Thessaloniki
Instrumentation Science and Technology

Amino acid analysis (AAA) is widely used for determining the composition of proteins and their concentration in foods, biological fluids, and tissues. Because of the vast number of amino acids, the chromatographic techniques provide separations of them based either on the charge or on hydrophobicity differences. Several chromatographic techniques have been applied for this purpose, with the method of choice being ion-exchange chromatography followed by post-column derivatization, as a more rugged and reproducible method provides excellent amino acid separation with relative freedom from interferences. This review considers recent relative reviews, current separation techniques, the most popular post-column reactions for amino acid analysis, comparison with the pre-column methods, the strategies used to develop effective post-column methodology, instrumentation technology, and applications in food and clinical analysis. The focus of the article is on liquid chromatographic methods coupled with post-column derivatization in order to increase sensitivity and selectivity, illustrating the versatility of the post-column derivatization (PCD) instrumentation for practical analysis. Copyright © Taylor & Francis Group, LLC. Source

Kazafeos K.,Alexander Technological Educational Institute of Thessaloniki
Diabetes Research and Clinical Practice

The term incretin effect was used to describe the fact that oral glucose load produces a greater insulin response than that of an isoglycemic intravenous glucose infusion. This difference has been attributed to gastrointestinal peptides GLP-1 and GIP. Since incretin effect is reduced in subjects with type 2 diabetes, despite GLP-1 activity preservation, two forms of incretin-based treatment have emerged: GLP-1R agonists, administered subcutaneously and DPP-4 inhibitors, administered orally. There is a great interest whether incretin-based treatment will be associated with sustained long-term control and improvement in β-cell function. The observation that GLP-1R agonists improve myocardial function and survival of cardiomyocytes highlights the need for further studies. Incretin-based therapies offer a new option and show great promise for the treatment of type 2 diabetes. © 2011 Elsevier Ireland Ltd. Source

Anagnostopoulos C.A.,Alexander Technological Educational Institute of Thessaloniki
Construction and Building Materials

The use of superplasticisers in microfine or regular cement-based grouts has become of vital importance in advanced professional grouting practices. These superplasticisers play an important role in the production of more durable grouts with improved rheological characteristics. This report presents a laboratory study of the effects of a new-generation polycarboxylate superplasticiser (PCE) on the rheological properties, mechanical strength, final setting time and bleeding of cement grouts in comparison to that of a polynaphthalene superplasticiser (SNF). The experiments were conducted using different superplasticiser dosages with cement grouts proportioned with a water to cement ratio (w/c) of 0.33, 0.4 or 0.5. The results showed that grouts with PCE had higher viscosity, slightly increased bleeding and longer setting times compared with the SNF admixture. However, the PCE improved the final strength, especially for grouts with a w/c ratio of 0.4 and 0.5, and decreased the yield stress. © 2013 Elsevier Ltd. All rights reserved. Source

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