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Search Results: 1 - 10 of 22 matches for " Theofilos Tourtas "
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Preventive Effects of Omega-3 and Omega-6 Fatty Acids on Peroxide Mediated Oxidative Stress Responses in Primary Human Trabecular Meshwork Cells
Theofilos Tourtas, Marco T. Birke, Friedrich E. Kruse, Ulrich-Christoph Welge-Lüssen, Kerstin Birke
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031340
Abstract: Pathologic processes in glaucoma include increased apoptosis, accumulation of extracellular material in the trabecular meshwork and optic nerve, condensations of the cytoskeleton and precocious cellular senescence. Oxidative stress was shown to generate these alterations in primary ocular cells. Fatty acids omega-3 and -6 are alleged to constitute a prophylaxis against these deleterious effects. Here, we tested actual preventive effects omega-3 and -6 against peroxide induced stress responses in primary human trabecular meshwork cells. Changes of mitochondrial activity, proliferation, heat shock proteins, extracellular matrix components, and inflammatory markers were evaluated. Alterations of the cytoskeleton were evaluated by phalloidin labeling. Here we report a repressive effect of omega-6 on metabolic activity and proliferation, which was not detected for omega-3. Both agents were able to prevent the anti-proliferative effect of H2O2, but only omega-3 prevented metabolic repression. Expression of heat shock protein 27 was unaltered by both fatty acids, whereas heat shock protein 90 was significantly induced by both. Omega-6 increased fibronectin and connective tissue growth factor synthesis, as well as the amount of secreted fibronectin. Omega-3, instead, induced plasminogen activator inhibitor 1 synthesis. H2O2 further increased fibronectin production in omega-6 supplemented cells, which was not the case in omega-3 treated cells. H2O2 stimulation of plasminogen activator inhibitor 1 and connective tissue growth factor was repressed by both fatty acids. Both fatty acids appeared to abolish H2O2 mediated stimulation of nuclear factor κB and IL-6, but not IL-1α and IL-8. H2O2 induced formation of cross-linked actin networks and stress fibers, which was reduced by preemptive application of omega-3. Omega-6, in contrast, had no protective effect on that, and even seemed to promote condensation. Based on the observed side effects of omega-6, omega-3 appears to be the more beneficial fatty acid in respect of prophylactic intake for prevention of a glaucomatous disease.
The Place Branding of Istanbul for the Olympic Games of 2020
Pouliopoulos Theofilos
Podium : Sport, Leisure and Tourism Review , 2012, DOI: 10.5585/podium.v1i1.19
Abstract: This essay will examine one of the candidate cities of the 2020 Games, Istanbul. We are going to see the theoretical background of nation and place branding and how sports can be the ambassador of a nation. After, we will focus on Istanbul and Turkey. The political situation in Turkey and the role of the leading force in the Middle East is connected to a whole process for Turkey to gain power. The Olympic Games in Istanbul is a strategic point in this process and we are going to see what chances has Istanbul to host the greatest multi-sport event in the world. DOI: 10.5585/podium.v1i1.19
Site-specific Validation of Path Loss Models and Large-scale Fading Characterization for a Complex Urban Propagation Topology at 2.4 GHz
Theofilos Chrysikos,Stavros Kotsopoulos
Lecture Notes in Engineering and Computer Science , 2013,
The Role of Collybistin in Gephyrin Clustering at Inhibitory Synapses: Facts and Open Questions
Theofilos Papadopoulos,Tolga Soykan
Frontiers in Cellular Neuroscience , 2011, DOI: 10.3389/fncel.2011.00011
Abstract: Collybistin (Cb) is a brain-specific GDP/GTP-exchange factor, which interacts with the inhibitory receptor anchoring protein gephyrin. Data from mice carrying an inactivated Cb gene indicate that Cb is required for the formation and maintenance of gephyrin and gephyrin-dependent GABAA receptor (GABAAR) clusters at inhibitory postsynapses in selected regions of the mammalian forebrain. However, important aspects of how Cb’s GDP/GTP-exchange activity, structure, and regulation contribute to gephyrin and GABAAR clustering, as well as its role in synaptic plasticity, remain poorly understood. Here we review the current state of knowledge about Cb’s function and address open questions concerning its contribution to synapse formation, maintenance, plasticity, and adaptive changes in response to altered network activity.
A Back Propagation-Type Neural Network Architecture for Solving the Complete n × n Nonlinear Algebraic System of Equations  [PDF]
Konstantinos Goulianas, Athanasios Margaris, Ioannis Refanidis, Konstantinos Diamantaras, Theofilos Papadimitriou
Advances in Pure Mathematics (APM) , 2016, DOI: 10.4236/apm.2016.66033
Abstract: The objective of this research is the presentation of a neural network capable of solving complete nonlinear algebraic systems of n equations with n unknowns. The proposed neural solver uses the classical back propagation algorithm with the identity function as the output function, and supports the feature of the adaptive learning rate for the neurons of the second hidden layer. The paper presents the fundamental theory associated with this approach as well as a set of experimental results that evaluate the performance and accuracy of the proposed method against other methods found in the literature.
Evaluation of children 8 -9 years old based on their physical abilities
Biology of Exercise , 2009,
Abstract: This research deals with four basic abilities of two different samples. One group of 267 selected subjects, among a larger sample of 8 to 9 year old children and one of 211 non-selected. The target of the research was to evaluate the basic abilities, speed at 30 meters, endurance at speed with change of direction, jumping ability and throwing ability; furthermore, to found out the differences of performance among the two sexes at this age, separately for each sample; finally, to correlate the abilities of lower extremities that arise from the application of tests, with those of strength velocity at upper extremities, separately for boys and girls at selected and non selected subjects. Differences were examined with the one-way ANOVA,while the correlation was carried out by Pearson coefficient.Performances of boys of this age (8-9 years old) are statis-tically better than those of girls at all abilities measured innon-selected children (p<.001). However, in selected ones, the differences were smaller, mainly at speed the 70 meters from the standing position (p<.0001) and throwing strength velocity at upper extremities, as well as strength of vertical jump, at p<.05, while no difference was observed at speedwith change of direction at both sexes. Strength velocity atupper extremities is correlated to the basic abilities of lowerextremities more in non-selected children.
Wireless Information-Theoretic Security in an Outdoor Topology with Obstacles: Theoretical Analysis and Experimental Measurements
Theofilos Chrysikos,Tasos Dagiuklas,Stavros Kotsopoulos
EURASIP Journal on Wireless Communications and Networking , 2011, DOI: 10.1155/2011/628747
Wireless Information-Theoretic Security in an Outdoor Topology with Obstacles: Theoretical Analysis and Experimental Measurements
Chrysikos Theofilos,Dagiuklas Tasos,Kotsopoulos Stavros
EURASIP Journal on Wireless Communications and Networking , 2011,
Abstract: This paper presents a Wireless Information-Theoretic Security (WITS) scheme, which has been recently introduced as a robust physical layer-based security solution, especially for infrastructureless networks. An autonomic network of moving users was implemented via 802.11n nodes of an ad hoc network for an outdoor topology with obstacles. Obstructed-Line-of-Sight (OLOS) and Non-Line-of-Sight (NLOS) propagation scenarios were examined. Low-speed user movement was considered, so that Doppler spread could be discarded. A transmitter and a legitimate receiver exchanged information in the presence of a moving eavesdropper. Average Signal-to-Noise Ratio (SNR) values were acquired for both the main and the wiretap channel, and the Probability of Nonzero Secrecy Capacity was calculated based on theoretical formula. Experimental results validate theoretical findings stressing the importance of user location and mobility schemes on the robustness of Wireless Information-Theoretic Security and call for further theoretical analysis.
Decoding of Basic Emotions from Dynamic Visual Displays in Dementia: A Sign of Loss of Positivity Bias in Emotional Processing in Cognitively Unhealthy Aging?  [PDF]
Theofilos Gkinopoulos, Despina Moraitou, Georgia Papantoniou, Magdalini Nigritinou, Pantelis Ginos, Daphni Kotselidou
Open Journal of Medical Psychology (OJMP) , 2014, DOI: 10.4236/ojmp.2014.35034
Abstract: Difficulties in recognizing emotional signals might have serious implications for social interactions. Neurodegenerative diseases that affect neural networks involved in emotional displays processing might thus be connected with a disproportionate impairment in social life. This study aimed at examining the ability to decode basic emotions from dynamic visual displays in mild to moderate dementia. Thirty old adults diagnosed as demented, and 30 gender-matched healthy controls were administered a measure of emotion evaluation. The groups did not differ significantly in age and educational level. The emotion evaluation test was designed to examine a person’s ability to visually identify basic emotions and discriminate these from neutral expressions, when they were expressed as dynamic, subtle, day-to-day expressions. Results showed that demented participants had a great difficulty in recognizing the positively valenced emotions of happiness and pleasant surprise, while sadness, anger, and anxiety were the easiest emotions to recognize. Healthy controls were almost excellent on happiness recognition, while discrimination of non-emotional displays was the most difficult condition often mislabeled as anxiety or pleasant surprise. Results were mainly discussed in terms of socio-emotional selectivity theory positing that only older adults capable of exerting cognitive controlled favor emotional over non-emotional and positive over negative information.
Torsade de Pointes and Persistent QTc Prolongation after Intravenous Amiodarone
Anna P. Kotsia,Georgios Dimitriadis,Giannis G. Baltogiannis,Theofilos M. Kolettis
Case Reports in Medicine , 2012, DOI: 10.1155/2012/673019
Abstract: We report a case of torsade de pointes after intravenous amiodarone and concurrent hypokalemia. Despite treatment cessation and correction of electrolyte abnormalities, excessive QTc prolongation was noted, which persisted for 14 days. This prolonged course for QTc normalization may be attributed to the high rate of amiodarone loading and concurrent electrolyte disturbances coupled with possible underlying individual variability in pharmacokinetics.
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