Dissertations / Theses on the topic 'Μεταξάς'
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Κατσικογιάννη, Μαρία. "Διερεύνηση διεπιφανειακών φαινομένων μεταξύ βακτηρίων και βιοϋλικών." Thesis, 2008. http://nemertes.lis.upatras.gr/jspui/handle/10889/1236.
Full textOne of the major problems arising from the use of implants and medical devices and impeding their long-term use is the emergence of nosocomial septic incidents related to infections caused by Coagulase negative staphylococci, most notably by S. epidermidis. The extensive use of antibiotics has resulted in multi-resistant bacterial strains of normal flora, making the need for developing antibacterial biomaterials of great importance. For this purpose it is necessary to study and understand the mechanism of bacterial adhesion to the surface of biomaterials. In this direction, we investigated the influence of the physicochemical interactions between bacteria and materials, the shear rate and their relative contribution on the ability of bacteria to adhere to the biomaterial surface and to activate the ica genes, which are responsible for the production of extracellular polymeric (slime), and in particular for the production of polysaccharide intercellular adhesin (PIA), that mediates cell-cell interactions. For this study, the surface of existing biomaterials was modified by plasma methods, self-assembled monolayers were prepared on glass, and the materials were physicochemicaly characterized. The applicability of the colloidal theories, such as the thermodynamic, the DLVO and the extended DLVO, for the prediction of bacterial adhesion was examined as well. The results showed that the increase in material surface energy and its polar component reduced bacterial adhesion, whereas adhesion was not significantly influenced by the non-polar character of the material surface. The thermodynamic theory explained satisfactorily the results for high ionic strength solutions, while DLVO for solutions with low ionic strength. The extended DLVO theory explained well the effects of both the solution and material surface properties to bacterial adhesion. The increase in shear rate reduced the number of adherent bacteria in a manner that depended on the bacteria-material physicochemical interactions, but not in the way that the above theories predicted. Therefore, bacterial adhesion considered as the result of a combination of the physicochemical and hydrodynamic interactions, and the formation of macromolecular bonds. The investigation of ica genes expression showed that the expression enhanced by the decrease in the material surface energy the increase in shear rate.
Χιωτέλης, Ιωάννης. "Μελέτη της αλληλεπίδρασης μεταξύ προσροφημένων πολυμερικών στρωμάτων." Thesis, 2007. http://hdl.handle.net/10889/7860.
Full textFlexible polymer chains end-tethered to a surface in good solvent tend to extend away from the surface due to excluded volume interactions. At sufficiently high grafting densities the chains become elongated normal to the surface, this extension being opposed by an elastic restoring force of entropic origin to form a layer of stretched chains referred to as a “polymer brush”. These systems have been studied extensively in recent years by numerous experimental techniques and theoretical methods. In the present investigation we have studied asymmetric star-shaped polymers whereby the different arms are either non-adsorbing PS chains or short PB chains terminating in a zwitterionic end-group known to adsorb strongly on surfaces such as mica or quartz. In this manner, it is possible on the one hand to form brushes with a single PS chain, but multiple zwitterionic stickers, and on the other to study the reverse case of multiple non-adsorbing arms attached to a surface via a single zwitterions. We have used the surface force balance technique to determine the interaction between such brush-layers formed on mica and neutron scattering to determine the absorbed amount and interanchor distance. Interactions between polymer brushes formed by highly asymmetric star-like polymers with a long PS arm and one, two or three short PB arms each terminating in a zwitterionic end-group were studied in order to explore the effect of the sticking energy on the brush structure. Polystyrene stars with two and three tails bearing a single end group were also studied to investigate how the height of the adsorbed layer and the grafting density are affected. Our measurements show no significant differences between PS with 1, 2 and 3 end groups. This may be due to kinetic reasons since additional polymer chains are hindered from attaching to a brush-bearing surface. The behavior of two PS chains with one end-group ((PS)2-PB-X) seems not to differ appreciably from that of PS-PB-X copolymer. On the other hand three PS chains with one end-group ((PS)3-PB-X) appeared to form layers with smaller brush height and greater interanchoring distance, relative to PS-PB-X layers. We can attribute this to the extra stretching that the three-chain architecture imposes on the adsorbed brush. In the present investigation we have also studied weak polyelectrolytes. Polyelectrolytes (charged polymer chains) remain among the least understood materials despite their importance in biology (proteins, DNA) and materials science. Their behavior and characteristics are not yet fully understood because of complicated correlations due to their charged nature that gives rise to long-range interactions. The counterplay of their properties as polymers and electrolytes with counterions around polyelectrolyte chains imposes additional difficulties on explaining their behavior. The association of counterions around polyelectrolytes and the pH of the solution are two parameters than can affect the properties of such systems. Especially weak polyelectrolytes (like poly-acrylic acid) are even sensitive to pH changes because of the alterable degree of dissociation. We measured forces between two charged polymer layers of Poly (isoprene-acrylic acid) diblock copolymers adsorbed on mica surfaces. Poly (isoprene-acrylic acid) diblock copolymers can be adsorbed from one end (poly-isoprene) which is sorter than the poly-(acrylic acid) part. The properties of the polymer layer at various salt concentrations and different pH of the solutions were measured by Surface Forces Apparatus. Information about the height of the polymer layer, and the adsorbed amount were extrapolated. The extracted results were compared with theoretical predictions showing well fit.
Λουκόπουλος, Βασίλειος. "Υπολογιστική ρευστομηχανική '' εσωτερική ροή μεταξύ δύο περιστρεφόμενων σφαιρών ''." Thesis, 2001. http://nemertes.lis.upatras.gr/jspui/handle/10889/2201.
Full textΖερβός, Θεόδωρος. "Αλληλεπίδραση μεταξύ ασύρματων τερματικών συσκευών και του ανθρωπίνου σώματος." Thesis, 2007. http://nemertes.lis.upatras.gr/jspui/handle/10889/739.
Full textΤhe object of this doctoral thesis is the study, in depth analysis and modelling of the electromagnetic interaction between the human body and the antennas used in the handsets of modern wireless telecommunication systems. The aim is twofold. On one hand is the estimation of the antenna efficiency reduction that is caused by the presence of the user’s body in small distance and on the other hand is the study and precise determination of the electromagnetic radiation absorbed by the human body (especially the human head) at the use of a wireless terminal. The final aim is the contribution in the design of wireless terminals (e.g. mobile telephones) that will be more efficient in their operation and simultaneously safer for their user. In this thesis, an extensive study and analysis of the parameters related with the interaction between the wireless terminal antenna and the user’s body were realized. Experimental terminal prototypes were designed, modelled, constructed and measured in the presence of human head models in order to estimate the radiation absorption from the head and the degradation of the antenna efficiency. An appropriate measurements methodology at the far field was developed for the precise measurement of the terminal antenna characteristics. According to the results, an intense change of the antenna characteristics and of its radiation diagram in the presence of the user’s head was observed. Also, the rapid decrease of absorbed power and the increase of the efficiency were calculated after moving the handset away from the head. An important operation improvement was achieved with beamforming, which is realized using multiple antennas at the terminal. Finally, the effect of the user’s hand at MIMO terminal performance was examined and a reduction of the mean capacity of the channel in the presence of the hand was found.
Χρηστοπούλου, Βασιλική. "Ανάμιξη ασύμβατων μεταξύ τους πολυμερών χωρίς τη χρήση συμβατοποιητών." Thesis, 2000. http://nemertes.lis.upatras.gr/jspui/handle/10889/2441.
Full textΦραγκούλια, Αγγελική. "Επιδημιολογική έρευνα σχέσεως μεταξύ καρκίνου και μόλυνσης με μυκοβακτηρίδιο φυματίωσης." Thesis, 1992. http://nemertes.lis.upatras.gr/jspui/handle/10889/2806.
Full textΧατζάρας, Βασίλειος. "Γεωτομή εγκάρσια στις Ελληνίδες μεταξύ δυτικής Κρήτης και νήσων Κυκλάδων." Thesis, 2010. http://hdl.handle.net/10889/6490.
Full textThe Hellenides are part of the Alpine–Himalayan mountain chain in the eastern Mediterranean and form an orocline connecting the Dinarides to the north with the Anatolides/Taurides to the southeast. They comprise several continental fragments that were amalgamated by continent-continent collision between the Eurasian and Apulian plates during Late Mesozoic–Cenozoic times, following the obliteration of a series of intervening and interconnected Mesozoic ocean basins (Neo-Tethyan). The remnants of these ancient ocean basins are mainly represented by two narrow ophiolitic belts known as the Pindos and the Vardar sutures that divide the Hellenides into: (1) the External Zones, which represent the telescoped northern margin of the Apulia microcontinent; (2) the Internal Zones, which are built up by the Pelagonian zone and the Cycladic massif and (3) the Hellenic Hinterland, which is defined by the Serbomacedonian and the Rhodope massif. This dissertation concentrates in the area of southern and central/eastern Aegean in order to study the exhumation mechanism of high-pressure (HP) rocks, the role of compression and extension in the orogenic evolution of the Hellenides, the influence of pre-existing Mesozoic structures on the Cenozoic deformation pattern and to better understand the connection between the Hellenides and the Anatolides. To do so, geological and structural mapping were combined with kinematic, structural, paleostress (calcite twinning, fault-slip data), strain, petrofabric and vorticity analyses, carried out on central and western Crete island as well as on Amorgos and Astypalea islands. In central Crete, the evolution of windows was controlled by two main contractional phases of deformation. The first phase (D1) was related to the ductile-stage of exhumation. NNW-SSE compression during D1 caused layer- and transport-parallel shortening in the upper thrust sheets (Tripolitsa, Pindos and Uppermost units), resulting in nappe stacking via low-angle thrusting. Synchronously, intracontinental subduction led to HP metamorphism of the lower tectonic units (Plattenkalk and Phyllite-Quartzite units), which, however, did not affect the most external parts of the southern Hellenides. Subsequent upward ductile extrusion of HP-rocks was characterized by both down-section increase of strain and up-section increase of the pure shear component. The second phase (D2) was associated with the brittle-stage of exhumation. D2 was governed by NNE-SSW compression and involved conspicuous thrust-related folding, considerable tectonic imbrication and formation of a Middle Miocene basin. The major D2-related Psiloritis thrust, crosscuts the entire nappe pile and its trajectory partially follows and reworks the D1-related contact between upper and lower (HP) tectonic units. Eduction and doming of the Talea window, was accompanied by gravity sliding of the upper thrust sheets and by out-of-the syncline thrusting. Late-orogenic collapse also contributed to the exhumation process. Therefore, it seems that the HP-rocks of central Crete were exhumed under continuous compression and that the role of extension was previously overestimated. The structural architecture of western Crete was mainly established by two contractional deformation phases followed by an extensional phase. SSW-directed thrusting from Oligocene to Lower Miocene times (D1 phase) led to brittle stacking of the upper thrust sheets (Tripolitsa and Pindos units) and concomitant ductile exhumation-related imbrication of the lower HP tectonic units (Phyllite-Quartzite, Tripali and Plattenkalk units). Kinematic analysis in the Phyllite-Quartzite unit reveals a main southward ductile transport followed by late bulk coaxial deformation. Structural trends of ductile D1 thrusts define a salient bounded to the east by a NE-trending transverse zone (Omalos transverse zone) situated in the western margin of the Lefka Ori window. At the eastern limb of the salient, the trajectories of L1 stretching lineation formed on a gently dipping S1 foliation in the Phyllite-Quartzite unit, show a clockwise rotation with proximity to the transverse zone. This suggests that the latter might have acted as an oblique buttress against the southward extruding Phyllite-Quartzite unit rocks. D2 phase was governed by regional NNE to NNW compression related to a pure compressive to transpressive paleostress regime and involved significant folding and out-of-sequence with respect to D1 thrusting. The early D2a phase is related to the brittle-stage of exhumation of the HP-units and spans from Middle to Upper Miocene. D2a deformation involved thrust-related folding, tectonic imbrication and the formation of a Middle Miocene thrust-top basin, previously described as a supradetachment basin. The F2a folds are characterized by a predominant S(SE)-vergence and show a pronounced curvature of their hinge orientations from a regional E-W to a local NE-SW trend only present close to the transverse zone. In the latter, combined forward-directed imbricate thrusting and backthrusting led to the development of a major pop-up structure and a triangle zone, the latter cored by an Upper Miocene basin. Moreover, the trend of compression axes within the transverse zone are deflected from the regional NNE to NNW orientation to a local (W)NW orientation, which is perpendicular to the transverse zone. These findings suggest that the Omalos transverse zone should have served as an oblique ramp to the southward transport of HP-rocks, while the steep dip of the ramp may has impeded displacement of the Phyllite-Quartzite unit rocks up the ramp acting as a buttress to their foreland propagation. The D2b phase lasted from Upper Miocene to Lower Pleistocene and involved SW-directed thrust-related folding and synchronous sinistral strike-slip faulting. The D2b-related paleostress field is characterized by a NE compression orientation defining a pure compressive to transpressive regime. During Pleistocene, compression gave its place to (W)NW transtension/pure extension. The described kinematic evolution of southern Hellenides in western Crete reveals that the NE-trending transverse zone, which is possibly aligned with an inherited rift-related Mesozoic fault system, exerted significant control on the deformation pattern at progressively shallower crustal levels. The Phyllite-Quartzite unit rocks comprise the body of an extruded crustal scale shear zone confined at its base by a major ductile thrust, the Basal thrust. New finite strain data from the thrust-sense shear zone were used to describe the variation of ductile strain with structural distance (D) from the Basal thrust. Sampling was carried out along three traverses across central and western Crete. The strain ratio in XZ sections (RXZ) was obtained using the theta-curve, the mean object ellipse and the mean radial length methods. All methods give very consistent results. Based on these results, three strain profiles were constructed depicting a non-linear increase of RXZ values with proximity to the Basal thrust. Based on these profiles, an empirical logarithmic function of equation type RXZ=α−βlnD was obtained, describing the relationship between RXZ and D. Deformation in both central and western Crete occurred under approximately plane strain conditions, although deviations towards the fields of constriction and flattening have also been recorded. The vorticity profiles above the Basal thrust plane show a down section increase in the kinematic vorticity number (Wm) from 0.5 to 1 in western Crete and a simple shear-dominated deformation with the presence of local domains with a higher pure shear component in central Crete. A transport-parallel elongation of 20−110% has been estimated for the Phyllite-Quartzite unit, implying that S-directed extrusive flow controlled the formation and exhumation of the Phyllite-Quartzite thrust-sense shear zone. In central Aegean, the Cycladic island of Amorgos consists of two HP-units, the marble-rich Amorgos unit, which is correlated to the Mesozoic cover sequence of the Menderes massif, and the Cycladic Blueschist unit. The field-based structural study shows that the deformation history of the Amorgos HP-rocks was principally governed by Upper Eocene−Lower Miocene ductile to brittle thrusting (D1−D3) followed by Middle−Upper Miocene oblique contractional movements (D4−D5). The D1 phase caused syn-blueschist-facies ductile thrusting of the Cycladic Blueschist unit over the Amorgos unit, with ambiguous kinematics. Progressive deformation under continuous NW-SE compression produced a sequence of imbricate NW-directed thrusts (D2/3) characterized by a stratification of fault-related rocks, with mylonitic zones (D2) giving way downwards to cataclastic zones (D3). Parallelism between slickenside lineations and mylonitic L2 lineations in the D2/3 thrust zones, indicates a continuum of kinematics from ductile to brittle conditions. Ductile D2 thrusting synchronous to greenschist-facies retrogression, was accompanied by mega-sheath folding during constrictional and pure-shear dominated deformation. Brittle D3 thrusting was associated with NW-verging F3 folds trending at high-angle to the transport direction. Orthogonal contraction gave its place to transpression during which the compression orientation changed from NW-SE (D4) to NE-SW (D5). Back-arc related NW-SE pure extension (D6) seems to have been established in post-Upper Miocene times and related high-angle normal faulting affected HP-rocks only after they had already reached the uppermost crustal levels. Therefore, a syn-compressional exhumation process is favored for the HP-rocks of Amorgos island. In eastern Aegean, the island of Astypalea consists of Cretaceous to Eocene carbonate rocks capped by an Upper Eocene flysch, the Astypalea unit, which is correlated to the Mesozoic cover sequence of the Menderes massif and of tectonically overlying Jurassic marbles, which are considered as lateral equivalent of part the Lycian nappes. The deformation history of Astypalea was governed by Oligocene−Lower Miocene thrusting (D1) followed by Middle−Upper Miocene oblique contractional movements (D2) that in turn gave their place to post-Upper Miocene extension (D3, D4). The D1 phase caused NW-directed ductile to brittle thrusting of the Jurassic marbles over the Astypalea unit under continuous NW-SE compression. The stratification of fault-related rocks, with a mylonitic (D1a) upper and a cataclastic (D1b) lower part, as well as the parallelism between slickenside lineations and mylonitic L1a lineations in the D1 thrust zone, indicates a continuum of kinematics from ductile to brittle conditions. In the thrust zone footwall, brittle D1b thrusting was associated with NW-verging F1b folds that refold isoclinal F1a folds. Orthogonal contraction gave its place to WNW triclinic transpression (D2) during which deformation was partitioned in contraction-dominated (NE contraction) and wrench-dominated (NW-directed shearing) domains. N-S transtension to pure extension (D3) seems to have been established in Pliocene times and was followed by WNW transtension possibly active from post-Middle Pleistocene till present. Summarizing, the HP-rocks of southern and central Aegean were exhumed under continuous compression, albeit with opposite kinematics. Compression governed deformation throughout Oligocene to Lower Pliocene (Amorgos, Astypalea) or Lower Pleistocene (Crete) and the area was subjected to transtension/pure extension from Plio-Pleistocene onwards. Therefore, the role of extension in the exhumation of HP-rocks and the orogenic evolution of southern and central/eastern Aegean seems to be overestimated.
Δασκαλόπουλος, Ευάγγελος. "Ανάλυση παραγόντων αξιολόγησης διαμεσολαβητικών δικτυακών τόπων παροχής υπηρεσιών μεταξύ καταναλωτών." Thesis, 2012. http://hdl.handle.net/10889/6525.
Full textNowadays, the internet takes a great and important part in everyday lives in the majority of Greek people , whether at home, at work or in both locales. In the Internet world, users are consumers, and this facts has a great significance in understanding their expectations. This present study comprises an effort in approaching several criteria which could be taken into account for evaluating websites. In the first part of the study there is a theoretical approach which consists of several models of evaluation, based on the existing bibliography. In addition to the theoretical base, an empiric investigation is also represented, which has achieved for the evaluation of three specific websites with different content. The purpose is not to define which sites are “good” and which are “bad,” but rather is to help in identifying the factors that affecting the evaluation of websites. The data was analyzed by using SPSS 19 and Factor analysis method was used to identify the factors.
Βήχου, Χριστίνα. "Πρωτόκολλα συμφωνίας κλειδιού μεταξύ σταθμών σε ad-hoc ασύρματα δίκτυα." Thesis, 2013. http://hdl.handle.net/10889/5976.
Full textIn Ad-Hoc wireless networks we use symmetric or asymmetric cryptographic algorithms in order to make sure of the integrity of the sending data. We can choose between these two choices if we consider the available storage and computational resources of the stations. Key agreement protocols are used for the determining of their basic communication secret. In this master thesis I study the complexity of the key agreement protocols and I implemented the k-place elimination protocol of the paper "Distributively Increasing the Percentage of Similarities Between Strings with Applications to Key Agreement" and two new protocols (CAP and AAP).
Ζαφειρόπουλος, Διονύσης. "Διερεύνηση παραμέτρων σύγκλισης μεταξύ δικτύων κινητής τηλεφωνίας και ασυρμάτων δικτύων δεδομένων." Thesis, 2009. http://nemertes.lis.upatras.gr/jspui/handle/10889/1799.
Full textIn this thesis, an effort of presenting the technological landscape of the telecommunication market takes place, with focus on the interoperability between the Mobile Telephony Networks and the Wireless Data Networks and the relative changes that have evolved through this interoperability, both regarding the provided services and the applied business models by the enterprises of the specific market. Within the frames of this effort, a detailed recording of technological developments is realised, in terms of technical specifications and standards, in the two aforementioned categories of networks, so as to conclude to those standards that are utilized by the next generation networks (4G) which will be: • Networks that will be unified so as the different technological platforms will function smoothly. • Networks that will be characterized by low cost of deployment. • The end user will be continuously connected with a wireless access network, enjoying the preferred services anywhere and anytime. The master thesis structure follows the aforementioned methodology. The 1st Chapter includes a short presentation of expected results, both in terms of technologies and services for next generation networks, which we usually refer to as 4G networks (4th Generation) or B3G networks (Beyond 3G) or finally as All - IP wireless networks (AIPN). In the 2nd Chapter, a detailed presentation of Mobile Telephony Networks takes place, from their first versions (1G) until the most modern (3.5G) that have been presented up to today. The analysis includes both the various generations of networks and the used standards, in terms of modulation and multiplexing techniques. The rest of the chapter focuses on the technical description of the prevailing networks, GSM, GPRS and UMTS, while the chapter ends with a short description of intersystem handover processes between GSM and UMTS. Τhe 3rd Chapter, includes an extensive description of the Wireless Data Networks standards such as: IEEE 802.15 Wireless Personal Area Networks (WPANs) with main representatives networks based on Bluetooth and IrDA, standard IEEE 802.11 Wireless Local Area Networks (WLANs) mainly represented by WiFi and HyperLan/2, IEEE 802.16 Wireless Metropolitan Area Networks (WMANs) standard, widely known as WiMax and finally the IEEE 802.20 Wireless Wide Area Networks (WWANs) standard, namely Mobile Broadband Wireless Access (MWBA) that is still under development and aspires to constitutes the wireless version of the xDSL technology, since it aims to provide wireless broadband services. In the 4th Chapter methodologies for integrating the two types of networks, are presented along with examples of interoperability between GPRS / UMTS and WLANs or between UMTS and WiMAX. Extensive discussion around the problems that should be faced, as the guarantee of bearable QoS level, the mechanisms for handover between the networks and the management of mobility of users and terminals, is held. Moreover, examples of integrated networks with both loose and tight coupling methodologies are presented. The last section of the chapter concerns a detailed description of architectures for interconnecting heterogeneous wireless networks over IP – based backhaul networks, namely All – IP networks, with special focus on policy based handover mechanisms and techniques for managing micromobility and macromobility issues. The 5th Chapter concerns the changes taking place in the telecommunications market deriving from the technological progress in the subject of heterogeneous wireless networks interconnection. New service packets are created, as a result of new business plans that are drawn up by the big telecommunications organizations. Finally, we present the developments in the Greek market and subsidised projects from Information Society AE, via which wireless networks have been materialised, with aim to promote Broadband Services.
Βαφείδης, Παναγιώτης. "Διερεύνηση στοιχείων διαλειτουργικότητας μεταξύ δικτύων κινητής τηλεφωνίας και ασυρμάτων δικτύων δεδομένων." Thesis, 2009. http://nemertes.lis.upatras.gr/jspui/handle/10889/1798.
Full textIn this thesis, an effort of presenting the technological landscape of the telecommunication market takes place, with focus on the interoperability between the Mobile Telephony Networks and the Wireless Data Networks and the relative changes that have evolved through this interoperability, both regarding the provided services and the applied business models by the enterprises of the specific market. Within the frames of this effort, a detailed recording of technological developments is realised, in terms of technical specifications and standards, in the two aforementioned categories of networks, so as to conclude to those standards that are utilized by the next generation networks (4G) which will be: • Networks that will be unified so as the different technological platforms will function smoothly. • Networks that will be characterized by low cost of deployment. • The end user will be continuously connected with a wireless access network, enjoying the preferred services anywhere and anytime. The master thesis structure follows the aforementioned methodology. The 1st Chapter includes a short presentation of expected results, both in terms of technologies and services for next generation networks, which we usually refer to as 4G networks (4th Generation) or B3G networks (Beyond 3G) or finally as All - IP wireless networks (AIPN). In the 2nd Chapter, a detailed presentation of Mobile Telephony Networks takes place, from their first versions (1G) until the most modern (3.5G) that have been presented up to today. The analysis includes both the various generations of networks and the used standards, in terms of modulation and multiplexing techniques. The rest of the chapter focuses on the technical description of the prevailing networks, GSM, GPRS and UMTS, while the chapter ends with a short description of intersystem handover processes between GSM and UMTS. Τhe 3rd Chapter, includes an extensive description of the Wireless Data Networks standards such as: IEEE 802.15 Wireless Personal Area Networks (WPANs) with main representatives networks based on Bluetooth and IrDA, standard IEEE 802.11 Wireless Local Area Networks (WLANs) mainly represented by WiFi and HyperLan/2, IEEE 802.16 Wireless Metropolitan Area Networks (WMANs) standard, widely known as WiMax and finally the IEEE 802.20 Wireless Wide Area Networks (WWANs) standard, namely Mobile Broadband Wireless Access (MWBA) that is still under development and aspires to constitutes the wireless version of the xDSL technology, since it aims to provide wireless broadband services. In the 4th Chapter methodologies for integrating the two types of networks, are presented along with examples of interoperability between GPRS / UMTS and WLANs or between UMTS and WiMAX. Extensive discussion around the problems that should be faced, as the guarantee of bearable QoS level, the mechanisms for handover between the networks and the management of mobility of users and terminals, is held. Moreover, examples of integrated networks with both loose and tight coupling methodologies are presented. The last section of the chapter concerns a detailed description of architectures for interconnecting heterogeneous wireless networks over IP – based backhaul networks, namely All – IP networks, with special focus on policy based handover mechanisms and techniques for managing micromobility and macromobility issues. The 5th Chapter concerns the changes taking place in the telecommunications market deriving from the technological progress in the subject of heterogeneous wireless networks interconnection. New service packets are created, as a result of new business plans that are drawn up by the big telecommunications organizations. Finally, we present the developments in the Greek market and subsidised projects from Information Society AE, via which wireless networks have been materialised, with aim to promote Broadband Services.
Μαραθιά, Αικατερίνη. "Φαινοτυπικές και λειτουργικές διαφορές μεταξύ Τ λεμφοκυττάρων πνευμονικού παρεγχύματος και περιφερικού αίματος." Thesis, 1995. http://nemertes.lis.upatras.gr/jspui/handle/10889/2889.
Full textΚαρκούλιας, Γεώργιος. "Ανάλυση της μεταγωγής σήματος μεταξύ των τριών υποτύπων του α2-αδρενεργικού υποδοχέα." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/3660.
Full textΠαναγούλης, Αθανάσιος. "Διερευνητική εργασία για τη μελέτη της σχέσης μεταξύ ασθενών-πελατών και φαρμακοποιών." Thesis, 2010. http://nemertes.lis.upatras.gr/jspui/handle/10889/4117.
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Θεοδωρακόπουλος, Παναγιώτης. "Χαρτογράφηση της θαλάσσιας ζώνης μεταξύ Λευκάδας και Αιτωλοακαρνανίας από δορυφορικές εικόνες ASTER." Thesis, 2012. http://hdl.handle.net/10889/5522.
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Καραχρήστος, Απόστολος. "Χρονικά εξαρτώμενες συσχετίσεις μεταξύ τεσσάρων ευρωπαϊκών χωρών των αγορών κεφαλαίου και ομολόγων." Thesis, 2013. http://hdl.handle.net/10889/6210.
Full textThe purpose of this study is to look at the relationship between stock market and bond market in four European Countries (Germany, France, Spain and Italy) for the period of December 1999 to December 2012. We attempt to examine whether the correlations between two classes of assets are time varying by using multivariate conditional volatility models. The data we are daily yields on 10-year bonds and the closures of the stock markets of these countries for each one individually. We start our investigation by applying GARCH model of Bollerslev (1990). Finally, through co integration with the process of Johansen test will look at whether our series completed long influencing each other and their mutual dependence and causality of these relations. Our paper aims to show us whether there is a long correlation between these two markets in order to help managers and financial analysts to create a portfolio with less risk and greater efficiency. Our results show a long-term correlation between these two markets and one market affects the other in the long run, so it is useful to have a portfolio of both assets.
Τζίφρα, Κλεοπάτρα. "Σχολικές σχέσεις και δραστηριότητες μεταξύ Ελλήνων και αλλοδαπών μαθητών Ε΄ και Στ΄ Δημοτικού." Thesis, 2008. http://nemertes.lis.upatras.gr/jspui/handle/10889/953.
Full textThe present study refers to school relations and extracurricular activities of Greek and foreign students. Particularly, subjects, such as relationships among students as well as the impact students’ origin has on it or relationships between students and their teacher have been studied. Finally, there has been investigated the influence which family and school have on students’ choice of extracurricular activities.
Σωτηροπούλου, Μαρία. "Σχηματισμός διαλυτών διαπολυμερών συμπλόκων μεταξύ υδατοδιαλυτών συμπολυμερών και ασθενών πολυοξέων, πολυηλεκτρολυτών ή πρωτεϊνών." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/3567.
Full textΝτάρλας, Γεράσιμος. "Εφαρμογή των κοινωνικών δικτύων στον κλάδο των συναλλαγών μεταξύ των επιχειρήσεων (αγορά αγαθών)." Thesis, 2014. http://hdl.handle.net/10889/8144.
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Ντάβαρη, Αθηνά. "Εφαρμογή των κοινωνικών δικτύων στον κλάδο των συναλλαγών μεταξύ των επιχειρήσεων (αγορά υπηρεσιών)." Thesis, 2014. http://hdl.handle.net/10889/8145.
Full textSocial media have only recently begun to be used by Greek companies, as tools of communication strategy. Consequently, business executives operating in social media, without having yet developed an adequate field of empirical research to support and justify the feasibility of using these tools in terms of increased efficiency, or other marketing objectives. The aim of this quantitative study is to investigate the reasons, ways and intensity of activity in social media by businesses that operate in the market business (b-to-b), and the impact of this activity on enterprise performance. Specifically, the hypothesis (H1) that we control is that strategies use and intensity of use of social media positively influence business performance, in terms of increasing sales and finding new clients and suppliers. To perform our research we drew a quantitative questionnaire based on preliminary qualitative research with personal interviews of experts on the topic and review of literature. The research sample constituted 405 firms, which were selected randomly from Online social media LinkedIn (a total of 2620 Greek firms have weblog therein), which was the research framework of our research. The quantitative research instrument was sent electronically to the personal online account executives that seem to represent the company at LinkedIn. Total respondents 116questionairs, with a response rate of 28.64%. The survey was conducted between 06/04/2013 and 07/29/2013. Statistical analysis of our data was performed with the statistical package SPSS v.21. The quantitative analysis includes descriptive statistics (means, standard deviations, testing normality of distributions), exploratory factor analysis, reliability analysis, correlation, multiple regressions. The findings provided partial support for the hypothesis H1, which argued that the intensity and the strategic use of social media have a positive effect on business performance, in terms of sales growth, finding new partners and new suppliers. Further, the research results in basic conclusions about the selection criteria, the reasons and how we could activate social media in the best way.
Τάσσης, Κωνσταντίνος. "Υλοποίηση της υπηρεσίας διαλειτουργικότητας μεταξύ τεχνικών circuit cross connect & any transfer over MPLS." 2005. http://nemertes.lis.upatras.gr/jspui/handle/10889/162.
Full textThe subject of this paper is the implementation techniques of L2 MPLS VPNs Cicruit Cross Connect (CCC) and Any Trasfer over MPLS (AtoM) that are provided by the two main manufactures of network connection (Juniper and Cisco). Furthermore this paper searches the special technical features of each technique and tries to find ways of interoperability between those two. This is useful when a providing L2 MPLS VPNs service expands in a network that consists of equipment of these two main manufactures . In the special occasion of EDET, which is a completely «Cisco» network the upper has implementation in the connection limits with GEANT, which is a completely «Juniper» network. Therefore the providing of L2 MPLS VPN between any carrier that is connected with EDET (eg. Academic Institute) and another carrier that is behind GEANT (of course out of EDET) presupposes the solution of the interoperability problems between these techniques.
Πάκου, Αντωνία. "Μελέτη της σχέσης μεταξύ δείκτη εμπιστοσύνης του καταναλωτή και χρηματιστηριακών αποδόσεων στα ευρωπαϊκά χρηματιστήρια." Thesis, 2008. http://nemertes.lis.upatras.gr/jspui/handle/10889/1218.
Full textThis paper studies the relationship between stock market developments and confidence index for the 27 EU countries - members over the years 1985-2006. We found that for the majority of the EU countries exists positive correlation between the stock market index and the confidence indicators (consumer confidence indicator and economic sentiment indicator) in the short horizon. The changes between these indexes tempt to move in the same direction contemporaneously and in the short horizon (of 1 month), with the new EU members to be an exception. The correlation becomes almost zero in the long horizon. For the most of the EU countries there is causality between the variables. Stock returns in general Granger-cause the Consumer Confidence Index and the Economic Sentiment Indicator, but not vice versa. We found also that there is feedback causality relationship between stock returns and confidence for France and the EU as a whole.
Καρακίτσος, Σπύρος. ""Flora Ionica" : καταγραφή της χλωρίδας των Ιονίων νήσων και οι μεταξύ τους φυτογεωγραφικές συνδέσεις." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/1097.
Full textΚαθαράκης, Δημήτριος. "Flora sporadum : καταγραφή της χλωρίδας των Β. Σποράδων και οι μεταξύ τους φυτογεωγραφικές συνδέσεις." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/1099.
Full textΠαπακωνσταντίνου, Παναγιώτα. "Η σχέση μεταξύ αντιλαμβανόμενης διαφθοράς, γραφειοκρατίας, εισοδήματος και οικονομικής ανάπτυξης : διερεύνηση σε 180 χώρες." Thesis, 2011. http://hdl.handle.net/10889/5361.
Full textThe purpose of our research was to investigate the effect of corruption in certain macroeconomic variables. Specifically, we wanted to examine the relationship between corruption and income level, based on the classification of the World Bank (EH1), corruption and slow economic growth (EH2), corruption and bureaucracy (EH3), corruption and tax revenues (EH5) and finally corruption and military spending (EH5). The research assumptions EH1 and EH4 are investigated in a descriptive analysis, as the goal in a such analysis is the finding of a pattern in “symmetavoli” of two variables, while EH2 is investigated in an explanatory analysis, designed in measuring any casual relationship between two variables. For the investigation of the above research hypotheses, we have choosen a sample of 180 countries, for which the data were available, regarding the index value of perceived corruption (Corruption Perception Index, CPI) for 2008. These countries, according to the classification that used by the World Bank (for economies with population greater than 30.000 people) belong in one of the following four categories based on GNI (gross national income per capita) in 2009: - Low Income Countries: countries with Gross National Income per capita less than $995. - Countries of Lower-Middle Income: countries with GNI per capita between $996 and $3.945. - Countries of Upper-Middle Income:countries with GNI per capita between $3946 and $12.195. - High Income Countries: Countries with GNI per capita greater than $12.196.
Ποφάντης, Ερμής. "Μελέτη της επίδρασης των α5GABAA υποδοχέων στη συναπτική πλαστικότητα μεταξύ ραχιαίου & κοιλιακού ιπποκάμπου." Thesis, 2013. http://hdl.handle.net/10889/6968.
Full textThe hippocampal synapses display conspicuous ability for long-term plasticity which is thought to underlie learning and memory. Growing evidence shows that this ability differs along the long axis of the hippocampus, with the ventral CA1 hippocampal synapses displaying remarkably lower ability for long-term potentiation(LTP) compared with their dorsal counterpart when activated with high-frequency stimulation. Here, we show that low frequency, 10Hz stimulation induced LTP more reliably in DH than in VH CA1 field. Blockade of alpha5 subunit-containing GABAA receptors eliminated the difference between DH and VH. We propose that α5GABAA receptor-mediated activity plays a crucial role in regulating the threshold for induction of LTP especially at the ventral CA1 hippocampal synapses. This might have important implications for the functional specialization along the hippocampus.
Αλεξάκη, Αρχοντία, and Μαγδαληνή Κυριάκου. "Ανάπλαση ενδιάμεσου χώρου μεταξύ της Άνω και Κάτω πόλης Πατρών : ανάδειξη και ενοποίηση μνημείων." Thesis, 2008. http://hdl.handle.net/10889/8577.
Full textThe present postgraduate thesis aims at the investigation of maintenance and distinction of cultural goods, as well as the subject of integration in the modern way of life. Thus, it is structured in three parts. First part concerns in the institutional frame, which has to do with the subjects of safeguarding, but also in theoretical or technical approaches and factors that are related with the distinction. In the second part is exposed the urban and historical development of Patras. It is also located the region in the centre of city which suffers and is downgraded the most, and for this thesis will be called as the intermediary space of Upper and Down city of Patras, while in the third part takes place an effort of effectuation of a scheme, considered all the conclusions that were carried out by the first part, by design proposals, for the particular region.
Μπατζιόλας, Παναγιώτης. "Σχέση ιατρικού επισκέπτη-ιατρού με σκοπό τη βελτίωση της επικοινωνίας μεταξύ φαρμακευτικών εταιρειών και ιατρών." Thesis, 2011. http://nemertes.lis.upatras.gr/jspui/handle/10889/4625.
Full textFor decades researchers investigated the attitudes of doctors toward their information resources available for drugs on the market. The problem was always the same: always choose the doctor based on the needs of the patient, or are there other factors that influence the choices? What is the role of pharmaceutical companies and to what extent can determine the specific terms of the scientist? Medical sales represent the highlight of communication link of the pharmaceutical company with their doctors,. What is the opinion of physicians regarding the usefulness of this communication? Our aim in this work is to approach and understand the criteria by which the doctor chooses the means that it can be updated for the purchase of medicines. Our work will be divided into two parts, the first part (theoretical) will be the bibliographic approach and while it will select the final model that will build the second part, practical. In practical through the model, we will focus on specific areas of research, exploring, through questionnaires, media doctors, and their relationship with the medical visitors. The ultimate goal of our research is to explore these questions in order to draw lessons for improving communication between pharmaceutical companies and physician.
Χιωτέλης, Ιωάννης. "Μελέτη της προσρόφησης πολυ-ηλεκτρολυτών σε διεπιφάνειες με απ' ευθείας μετρήσεις δυνάμεων μεταξύ των αλυσίδων." Thesis, 2002. http://hdl.handle.net/10889/6520.
Full textThe forces between adsorbed charged diblock copolymers were measured, by the use of the Surface Force Apparatus. Diblock copolymers forming a polymer brush structure were investigated in order to measure the adsorbed layer thickness and their behavior in salt solutions with different concentrations. As we investigate there is an interesting conformation related with the adsorbed layer. It seems to consist by two sections, an anchoring layer and a solvated brush in solution. The anchoring layer is formed from the hydrophobic blocks of the diblock polyelectrolytes. The hydrophilic blocks form a brush in solution. Positive counter ions that are found in conjunction with the negative charges on the polyelectrolyte disassociate in solution. There are as many counter ions as charges on the chain. The presence of salt in the solution means more disassociated ions in the solution. Changes to the salt concentration leads to changes to the forces as well as to the adsorbed layer. We investigate four different molecular weights of the sulfonated polyelectrolyte PtBS-NaPSS (90K, 120K, 150K, 400K) by changing the salt concentration. We find out that the adsorbed layer thickness decreases while the molecular weight increases. We also detect reduce to the layer thickness with salt concentration reduction. The adsorbed amount seems to reduce by increasing the molecular weight and increases by salt concentration reduction. Although the most important conclusion is the anchoring layer which forms a stiff layer very close to the substrate. Finally these polymeric systems can be used in numerous industrial applications as colloid stabilization, biocompatibilization, adhesion, and water treatment e.t.c.
Παρασκευουλάκου, Μπόκολα Παναγιώτα. "Τεκτονική ανάλυση της επαφής μεταξύ Φυλλιτικής-Χαλαζιτικής σειράς και ζώνης Τρίπολης στην περιοχή του Πάρνωνα." Thesis, 2013. http://hdl.handle.net/10889/7487.
Full textStractural analysis of the contact of the Phyllite-Quartzite series and the Tripolitsa limestones to the eastern margin of Parnon. As, however, the structural analysis and the geological history of the region of two tectonic windows of Parnon and Taygetos.
Πέττα, Κοραλία. "Διαφορά αντιμετώπισης συγκεκριμένων προβλημάτων της σχολικής πράξης μεταξύ δασκάλων πτυχιούχων Παιδαγωγικών Ακαδημιών και δασκάλων πτυχιούχων Παιδαγωγικών Τμημάτων." Thesis, 2012. http://hdl.handle.net/10889/6085.
Full textIn this research study we aim to explore the differences between teachers graduated from the Pedagogical Academies and those who graduated from the Primary Education Departments in coping with specific problems of school practice. We focus on the investigation of the teachers’ perceptions and pedagogical practices concerning discipline, diversity and students’ evaluation issues. With the method of the questionnaire we investigated the conceptions of 22 teachers graduated from Pedagogical Academies and 70 teachers graduated from the Primary Educations Departments. Our interpretative framework is the theory of social change, and in particular the theories Karl Marx and Max Weber, the theory of explaining and the theory of interpreting the social change. Through the analysis of the data it becomes obvious that the quantitative and qualitative change in the primary teachers’ education (from the two-year Pedagogical Academy in a four-year University Department) produced teachers with new pedagogical concepts and new intentions in school educational practice. The role of the teacher, as well as the characteristics of the teachers’ education has changed radically. The new type of the primary teacher, who studies at the Departments of Primary Education teacher of Pedagogical Department, has scientific identity and professional training. We consider that the improvement of the level of teachers’ studies brought change on the way of thinking and practicing and therefore social change. Teachers graduated at the Departments of Education operate within the school as agents of change and thus in the long run as factors social change: when the school is changing, slowly but surely, the society is changing as well.
Σαράντης, Κωνσταντίνος. "Συγκριτική μελέτη των φαρμακολογικών ιδιοτήτων του συμπλόκου του υποδοχέα GABAA/Βενζοδιαζεπινών μεταξύ του διαφραγματικού και κροταφικού ιπποκάμπου επίμυος." 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/464.
Full textΟ ιππόκαμπος στον αρουραίο είναι μια δομή σε C-σχήμα που εκτείνεται από τον διαφραγματικό πυρήνα προσθιοραχιαία έως τον κροταφικό λοβό οπισθιοκοιλιακά. Παρόλο που από παλιά θεωρείτο ως ομοιογενής δομή, έχουν παρατηρηθεί πολλές διαφορές σε όλα τα επίπεδα οργάνωσης μεταξύ του διαφραγματικού και του κροταφικού ιππόκαμπου. Οι βενζοδιαζεπίνες δρουν στις θέσεις δέσμευσης των βενζοδιαζεπινών, οι οποίες είναι αλλοστερικά συνδεδεμένες με το σύμπλοκο του GABAA, όπου ενισχύουν την δράση του GABA στους GABAA υποδοχείς, αυξάνοντας τη συχνότητα ανοίγματος του διαύλου των ιόντων χλωρίου (Cl-) και έχοντας μικρή μόνο επίδραση στο χρόνο ανοίγματος ή στην αγωγιμότητα του διαύλου. Προηγούμενη μελέτη υποδεικνύει ότι η έκφραση των α1-, β2- και γ2-υπομονάδων ήταν μικρότερη, ενώ αντίθετα η έκφραση των α2-, α5- και β1-υπομονάδων ήταν μεγαλύτερη στον κροταφικό ιπποκάμπο σε σύγκριση με τον διαφραγματικό ιππόκαμπο. Σύμφωνα με προηγούμενες μελέτες που αφορούν την συνέκφραση των υπομονάδων στο σύμπλοκο του GABAA υποδοχέα τα αποτελέσματα μας υποδηλώνουν ότι ο α1β2-υποτύπος του GABAA υποδοχέα επικρατεί στον διαφραγματικό ιππόκαμπο (ΔΙ), ενώ ο α2β1-υπότυπος κυριαρχεί στον κροταφικό ιππόκαμπο (ΚΙ). Επιπλέον, φαρμακολογικές μελέτες έχουν δείξει ότι η καταπραϋντική δράση της diazepam πραγματοποιείται μέσω των GABAA υποδοχέων, που περιέχουν την α1-υπομονάδα, ενώ η αγχολυτική δράση της πραγματοποιείται μέσω των υποδοχέων που φέρουν την α2-υπομονάδα. Επομένως, η μελέτη των φαρμακολογικών ιδιοτήτων των υποτύπων του GABAΑ υποδοχέα δίνει την δυνατότητα στο να σχεδιαστούν ειδικά φάρμακα τα οποία θα βελτιώνουν το κλινικό προφίλ ασθενειών, όπως το άγχος, η αϋπνία ή η επιληψία, δρώντας σε εξειδικευμένους υποτύπους του GABAΑ υποδοχέα. Ο στόχος της συγκεκριμένης εργασίας ήταν να μελετηθούν οι φαρμακολογικές ιδιότητες των υποτύπων του συμπλόκου του GABAA υποδοχέα/βενζοδιαζεπινών στον διαφραγματικό σε σύγκριση με τον κροταφικό ιππόκαμπο επίμυος. Έτσι, για τη μελέτη των θέσεων δέσμευσης των βενζοδιαζεπινών μεταξύ του διαφραγματικού και κροταφικού ιπποκάμπου χρησιμοποιήθηκε ο ευρέως φάσματος αγωνιστής των θέσεων δέσμευσης των βενζοδιαζεπινών, [3H]-flunitrazepam, σε μια αυτοραδιογραφική μελέτη. Επιπλέον, χρησιμοποιήθηκαν εξειδικευμένα φάρμακα, που δεσμεύονται σε συγκεριμένους υποτύπους του GABAA υποδοχέα, όπως το zolpidem (ειδικός αγωνιστής των GABAA υποδοχέων, που περιέχουν την α1-υπομονάδα), το etomidate (ειδικός θετικός αλλοστερικός ρυθμιστής των GABAA υποδοχέων, που περιέχουν τη β2-υπομονάδα) και το L-655,708 (ειδικός αντίστροφος αγωνιστής των GABAA υποδοχέων, που περιεχούν την α5-υπομονάδα) σε μια αυτοραδιγραφική κινητική μελέτη. Τα αποτελέσματα μας έδειξαν ότι οι τομές που προέρχονταν από τον ΚΙ συγκρινόμενες με αυτές από τον ΔΙ είχαν: Α) μειωμένη δέσμευση της [3H]-flunitrazepam στις CA1, CA3 και DG περιοχές, Β) μικρότερη χημική συγγένεια της δέσμευση της [3H]-flunitrazepam στη CA1 περιοχή, Γ) καμία διαφορά στον αριθμό των θέσεων δέσμευσης, Δ) μεγαλύτερες τιμές IC50 και EC50 για το zolpidem και το etomidate, αντίστοιχα και Ε) μικρότερες τιμές IC50 για το L-655,708. Συμπερασματικά, τα αποτελέσματά μας υποδεικνύουν διαφορετικές φαραμκολογικές ιδιότητες των υποτύπων του GABAΑ/ΒΖ υποδοχέα μεταξύ του ΔΙ και ΚΙ, ενώ επιβεβαιώνεται και ενισχύεται προηγούμενη μελέτη που υποδηλώνει ότι ο α1β2-υποτύπος του GABAA υποδοχέα επικρατεί στον διαφραγματικό ιππόκαμπο (ΔΙ), ενώ ο α2β1-υπότυπος κυριαρχεί στον κροταφικό ιππόκαμπο (ΚΙ). Η μελέτη αυτή είναι πιθανό να τυγχάνει ιδιαίτερης κλινικής αξίας, στην κατεύθυνση της ακριβέστερης ρύθμισης των αποτελεσματικών δόσεων των διάφορων μορίων που δρουν στις θέσεις δέσμευσης των βενζοδιαζεπινών των α1- και α2-υποτύπων του GABAA υποδοχέα.
The hippocampus in the rat appears grossly as an elongated structure with its long axis bending in a C-shaped manner from the septal nuclei rostrodorsally to the incipient temporal lobe caudoventrally. The long axis of the hippocampal formation is referred as the dorsoventral axis. Although hippocampus has been traditionally thought as a homogeneous structure, several studies have been demonstrated differences at several organization levels (from the behavioural to the cellular) between its dorsal (DH) and ventral (VH) pole. Pharmacological studies have shown that the α1-GABAA receptor subtype is associated with the sedative and anticonvulsant effects of benzodiazepines (BZs), whereas the α2-subtype is associated with the anxiolytic effects of BZs. Recent data have demonstrated a differential distribution of the GABAA receptor subunits between DH and VH, with the α1/β2 GABAA receptor subtype dominating in the DH and the α2/β1 subtype prevailing in the VH. We therefore study possible differences in the pharmacological properties and receptor binding parameters of the GABAA/BZ receptor subtypes between DH and VH, by examining: 1a) the specific binding of [3H]-flunitrazepam (BZ sites agonist), by using quantitative autoradiography, b) the kinetic parameters of [3H]-flunitrazepam specific binding, by using the “wipe off” technique and 2) the competitive displacement of [3H]-flunitrazepam binding by using zolpidem (a specific agonist of α1-subtype) and L-655,708 (a specific inverse agonist of α5-subtype) and the enhancement of [3H]-flunitrazepam binding by using etomidate (a selective positive modulator of β2- subunit), in an autoradiographical saturation kinetic study. Our results showed in VH compared to the DH: A) lower level of [3H]-flunitrazepam binding in CA1, CA3 and DG regions, B) higher KD value for [3H]-flunitrazepam specific binding in CA1 region and no differences in the Bmax value, C) higher IC50 and EC50 values for zolpidem and etomidate, respectively and D) lower IC50 values for L-655,708. In conclusion, the lower affinity of GABAA receptors for [3H]-flunitrazepam binding, the higher IC50 and EC50 values for zolpidem and etomidate, respectively, as well as the lower IC50 values for L-655,708 observed in VH compared to DH, support the evidence that the α1/β2-GABAA receptor subtype dominates in DH and the α2/β1-subtype prevails in VH and suggest differential pharmacological effects of the benzodiazepines in DH compared to VH, which could be of clinical relevence for the more accuate adjustment of the effective dose of α1- and α2-subtype specific BZ binding sites’ ligands.
Σπυροπούλου, Παρασκευή. "Μελέτη της σχέσης μεταξύ προφυλακτικών μέσων και βαρύτητας της κρανιοεγκεφαλικής κάκωσης βαθμολογούμενης σύμφωνα με την κλίμακα της Γλασκώβης." Thesis, 1995. http://nemertes.lis.upatras.gr/jspui/handle/10889/2875.
Full textΜαστρογιάννη, Ορθοδοξία. "Σύγκριση του μηχανισμού σηματοδότησης μεταξύ του φυσιολογικού και του πολυμορφικού α2Β-αδρενεργικού υποδοχέα σε νεφρικά και νευρικά κύτταρα." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/3657.
Full textΓρουζή, Ελισάβετ Ι. "Συγκριτική μελέτη μεταξύ υψηλών δόσεων σιπροφλοξασίνης έναντι κεφταζιντίμης+ αμικασίνης ως εμπειρική θεραπεία σε ουδετεροπενικούς ασθενείς που εμφανίζουν εμπύρετα επεισόδια." Thesis, 2006. http://nemertes.lis.upatras.gr/jspui/handle/10889/1180.
Full textThe aim of the present study was to compare administration of ciprofloxacin, given initially at the higher intravenous dose 400 mg three times a day for at least 72 hours, followed by oral administration 750 mg twice a day, with the standard combination regimen of ceftazidime plus amikacin as empiric treatment in patients with febrile neutropenia. In a prospective study, a total of 123 febrile neutropenic patients were randomized: 61 in the ciprofloxacin group and 62 in the ceftazidime plus amikacin group. In 78,1% of the patients acute leukemia was the underlying disease, another 19,5% of the patients suffered from high-grade non-Hodgkin’s lymphoma, and the remaining 2,4% of the patients suffered from aplastic anemia. The frequency of successful clinical response without modification at the end of therapy was almost identical for ciprofloxacin [49,2% (30/61 patients)] compared with that for ceftazidime plus amikacin [50% (31/62 patients)], (p=1,00). For 40/61 (65,6%) patients, it was possible to switch from parenteral ciprofloxacin to the oral after a mean of 4,3±069 days, and the response was successful for 30/40 (75%) patients. Gram-positive organisms accounted for 56,8% of all organisms isolated. The response to therapy in ciprofloxacin group was 40,0% for the microbiologically documented infections, 50% for the clinically documented infections and 55,2% for the episodes with fever of unknown origin, compared with 41,2%, 43,8% and 58,6% respectively in ceftazidime plus amikacin group. The efficacies of the regimens against gram-positive bacteremias were 20% for the ciprofloxacin group and 12,5% for the combination group. Superinfections were seen in 6 episodes in ciprofloxacin group and 4 episodes of reinfection in ceftazidime plus amikacin group (p=0,006). 3 patients (2 of ciprofloxacin group and 1 of combination group) died within 72 hours of randomization. Another 11 patients (7 vs 4 respectively, p=0,363) died before resolution of neutropenia. Of the total 12/14 patients died because of infection. The analysis of the data shown that the prolonged and severe granulocytopenia is a critical factor for the successful outcome. In ciprofloxacin group the neutropenia with neutrophils <100/μl for 14 days or more is significantly associated with the response to treatment (p=0,003). In the combination group this association is not significant (p=0,07). Logistic regression analyses were performed to estimate the probability of success and to identify “low risk” neutropenic patients. The covariates could be assessed at the onset of fever and during treatment as well. Among the tested covariates, the following variables were significant predictors of outcome at the onset of fever: absence of signs of clinically documented infection, neutrophils >100/μl, primary disease in remission, fever developing more than 10 days from the recent course of chemotherapy and outpatients status before the onset of fever. The significant predictors of outcome during treatment were: increasing neutrophils count >100/μl, increasing neutrophils count >500/μl, neutrophils <100/μl for less than 14 days and neutrophils <500/μl for less than 14 days as well. Furthermore episodes with 14 days or more of neutropenia <100/μl treated with ceftazidime plus amikacin had response rates 2,75 times higher compared to episodes treated with ciprofloxacin (p=0,038, odds ratio=2,75). Adverse events were mostly self-limited and were observed in 9 (14,7%) ciprofloxacintreated patients and 10 (16,1%) patients who were receiving the combination. In summary, this trial suggests that high-dose ciprofloxacin is therapeutically equivalent to the routine regimen of ceftazidime plus amikacin in “low risk” febrile neutropenic patients and has the advantages of intravenous and oral administration, without nepfro- and ototoxicity. However, it is very important that before an empirical therapy is chosen each hospital determine bacteriologic predominance and perform resistance surveillance.
Μπόκιας, Γεώργιος. "Συμπλοκοποίηση πολυμερών μέσω δεσμών υδρογόνου : αλληλεπιδράσεις μεταξύ του πολυακρυλικού οξέος ή συμπολυμερών του ακρυλικού οξέος και μη ιοντικών πολυβάσεων." Thesis, 1994. http://nemertes.lis.upatras.gr/jspui/handle/10889/2437.
Full textΠραγιάτη, Αγγελική Σ. "Ολοκληρωμένο σύστημα ανάπτυξης κατανεμημένων εφαρμογών βιομηχανικού ελέγχου με έμφαση στο μοντέλο διαχείρισης των περιορισμών πραγματικού χρόνου μεταξύ ετερογενών συσκευών." Thesis, 2004. http://nemertes.lis.upatras.gr/jspui/handle/10889/3243.
Full textΕυστρατίου, Μαρία-Αδαμαντία. "Σχέση μεταξύ ολικών κολοβακτηριοειδών, κοπρανωδών κολοβακτηριοειδών, κοπρανωδών στρεπτοκόκκων και Salmonella spp, Staphylococcus aureus, Candida albicans σε θαλάσσιο νερό περιοχών αναψυχής." Thesis, 1997. http://nemertes.lis.upatras.gr/jspui/handle/10889/2744.
Full textΠαύλου, Χάρης. "Η προληπτική αντιαρρυθμική θεραπεία στην οξεία φάση του εμφράγματος μυοκαρδίου, αιμοδυναμική συγκριτική μελέτη μεταξύ νέων ουσιών : σιβενζολίνη, φλεκαϊνίδη, μεξιλετίνη, προπαφαινόνη." Thesis, 1996. http://nemertes.lis.upatras.gr/jspui/handle/10889/2887.
Full textΘεοδοσίου, Ιωάννης, and Κωνσταντίνος Μπάλλας. "Κατανεμημένος έλεγχος κυκλοφορίας με σκοπό τη βελτιστοποίηση των συνθηκών ασφάλειας." Thesis, 2014. http://hdl.handle.net/10889/8154.
Full textDistributed traffic Control for Optimisation of the Safety Conditions.
Αγγελόπουλος, Ηρακλής. "Ο εκπαιδευτικός από τη σκοπιά των μαθητών : μια εμπειρική έρευνα μεταξύ μαθητών πρωτοβάθμιας εκπαίδευσης στο πλαίσιο της πολιτισμικής σχολικής ετερότητας : η περίπτωση του νομού Αχαΐας." Thesis, 2008. http://nemertes.lis.upatras.gr/jspui/handle/10889/1214.
Full textThis research was premised upon the fact that students feedback is very important. The purpose of this study was to determine elementary school students perceptions of the ideal teacher within a multicultural classroom environment in Patras elementary public school.
Μόσχοβος, Χρήστος. "In vitro ηλεκτροφυσιολογική μελέτη των μηχανισμών διαφοροποίησης μεταξύ διαφραγματικού και κροταφικού ιπποκάμπου ως προς την παθογένεση της επιληψίας, την συναπτική ευπλαστότητα και τη δικτυακή ρυθμογένεση." Thesis, 2009. http://nemertes.lis.upatras.gr/jspui/handle/10889/1880.
Full textFunctional segregation along the dorso-ventral axis of the hippocampus refers to epilepsy too. Using the model of magnesium-free medium and field recordings, single epileptiform discharges displayed higher incidence, rate, duration and intensity in ventral compared with dorsal rat hippocampal slices. The NMDA receptor antagonist AP5 shortened the discharges in ventral slices only. At 5 and 10μΜ of NMDA application 51% of the ventral but only 9% of the dorsal slices displayed persistent epileptiform discharges. We propose that the NMDA receptors contribute to the higher susceptibility of the ventral hippocampus to expression and long-term maintenance of epileptiform discharges. To study epileptogenesis following withdrawal of adenosinergic tone we used models of selective or non-selective blockade of adenosine receptors in magnesium-free medium and we recorded spontaneous or evoked field potentials in CA3 in dorsal as well as ventral slices. Blockade of A1 resulted in epileptogenesis in 31,13% of dorsal and in 52,76% of ventral slices used (P<0,05). NMDAR blockade increased epileptogenesis scores in both poles (76,38% in dorsal slices vs 80,68% in ventral slices). This NMDAR-dependent epileptogenesis was significantly aborted by blockade of A2R more in dorsal slices. Blockade of A1R under conditions of NMDAR blockade resulted to a similar increase of fEPSP slope in dorsal and ventral slices. The additional blockade of A2R decreased fEPSP slope to its original value in dorsal slices only. Simultaneous blockade of A1 and A2 receptors induced epileptogenesis practically in ventral slices only. This epileptogenesis was partially NMDA-dependent. Futrhermore A1R blockade resulted to an increase of fEPSP area under conditions of magnesium-free medium in dorsal slices only, whereas simultaneous blockade of both A1 and A2 receptors to an increase by 196,62% in dorsal slices and by 105,26% in ventral slices. We conclude that the selective or not blockade of adenosine receptors induces different kinds of epileptogenesis and this can be attributed to the different actions of adenosine receptors and the capability of ventral hippocampus to support NMDA-dependent epileptogenesis Employing field recordings from ventral hippocampal slices and two models of epileptogenesis, we found that HFOs associated with epileptiform bursts and excitatory synaptic transmission were co-modulated during epileptogenesis Pathological HFOs>200Hz were unequivocally present in persistent bursts induced by NMDA receptor-dependent but not NMDA receptor-independent mechanisms. The duration of pathological HFOs associated with persistent bursts but not of HFOs associated with bursts before the establishment of epileptogenesis was linearly and strongly correlated with the duration of bursts. Using 100Hz trains and medium with a higher concentration of potassium cations we induced LTP by stimulating associational/commissural fibers in CA3 region under conditions of NMDA receptor blockade. This new type of NMDAR-independent LTP displayed slow kinetics, did not change paired pulse facilitation and was prevented by simultaneous blockade of nifedipine-sensitive calcium channels. The incidence as well as the amplitude of LTP was greater in dorsal slices compared to ventral ones.
Θεοδωρακοπούλου, Γεωργία Φλ. "Η επίδραση της κοινωνικής υποστήριξης στις σχέσεις μεταξύ άγχους από την εργασία και ικανοποίησης από την εργασία, σε νοσηλεύτριες που εργάζονται σε ειδικές νοσηλευτικές μονάδες και γενικά νοσηλευτικά τμήματα." Thesis, 1995. http://nemertes.lis.upatras.gr/jspui/handle/10889/3173.
Full textΚακοσίμου, Ελένη. "Ασυμβασίες αντινεοπλασματικών φαρμάκων : Σχεδιασμός και ανάπτυξη κατάλληλης εφαρμογής για τον εντοπισμό και έλεγχο αυτών." Thesis, 2013. http://hdl.handle.net/10889/7635.
Full textMobile Health or mHealth, namely the use of mobile and wireless technologies in order to improve health services and achieve health goals, is today one of the most rapidly expanding fields of electronic health (eHealth). The number of health professionals that adopt smartphones to perform multiple tasks, during their everyday medical practice, is increasing constantly. This is due to the fact that smartphones provide advanced computing capabilities and high portability. Simultaneously, medication errors are among the most common medical errors which have negative impact both for the health of the patient and the expenditure on health sector. Drug prescribing is quite a complex procedure, considering the fact that requires the health expert to analyze multiple factors and retrieve, process, manage and digest large volume of information. According to the literature, the use of information technologies to assist health professionals in decision-making when prescribing drugs, can contribute significantly to the reduction of medication errors. In the context of our work, we explored and evaluated the major smartphone applications for drugs, aiming to the extraction of useful conclusions about the features and functions that they incorporate. One of the research key findings was the absence of a corresponding application for the drugs that are approved by the National Drug Organization of Greece. Therefore, we design and develop an application for checking drug-drug interactions which additionally provides the ability to view national formulary information about drugs. The analysis and design of the application was implemented in collaboration with future users, such as health professionals and patients, in order to ensure that will meet their needs and requirements and at the same time will remain user friendly. This application is intended for Android smart mobile devices (e.g. smartphones, tablet PCs) and the information that integrates is solely based on the national formulary of the National Drug Organization of Greece.
Τσαρούχας, Νικόλαος. "Electrophysiologιcal study of brain hypoxia." Thesis, 2009. http://nemertes.lis.upatras.gr/jspui/handle/10889/4120.
Full textΗ παρούσα ερευνητική εργασία στοχεύει στην ανάπτυξη εργαλείων Βιοϊατρικής Νευρομηχανικής (Βιοτεχνολογίες) για την σε βάθος λειτουργική μελέτη, ταχεία διάγνωση, συνεχή παρακολούθηση και έγκαιρη αντιμετώπιση οξέων και χρόνιων εγκεφαλικών διαταραχών, ατόμων που υπόκεινται σε ή πάσχουν από οιαδήποτε μορφή συστηματικής υποξαιμίας ή πιο εντοπισμένης εγκεφαλικής υποξίας, καθώς και για την λειτουργική αξιολόγηση και το συνεχή έλεγχο της προσαρμοστικότητας κατά την εξάσκηση των «υψιβατών», και γενικότερα ατόμων που ασκούν δραστηριότητες και λειτουργούν μέσα σε περιβάλλοντα αυξημένων οπτικο-γνωστικο-κινητικών απαιτήσεων (ένα είδος «στρες τεστ» για τον εγκέφαλο). Για το σκοπό αυτό υποβάλλουμε ολόκληρο το οπτικογνωστικό σύστημα, από το στοιχειώδες αισθητηριακό έως το πιο πολύπλοκο νοητικό επίπεδο, σε μια πειραματική δοκιμασία κατηγορικής διάκρισης σύνθετων οπτικογνωστικών ερεθισμάτων, μετά από υπερταχεία οπτική διέγερση που οδηγεί στην έκλυση κινητικής απάντησης κατά την κατηγοριοποίηση στόχων (εικόνες «ζώων» εκλύουν παραγωγικές αποκρίσεις) και στην καταστολή της κατά την κατηγοριοποίηση μη-στόχων (εικόνες «μη-ζώων» εκλύουν ανασταλτικές αποκρίσεις). Οι ταλαντωτικές ηλεκτροφυσιολογικές αποκρίσεις που συγχρόνως καταγράφονται στις ινιακές-κροταφικές-βρεγματικές περιοχές του εγκεφάλου αναλύονται στο πεδίο του χρόνου (<20Hz) και στο συζευγμένο χρονοφασματικό πεδίο ευρυζωνικά (1-60Hz) με το συνεχή μετασχηματισμό του κυματίου που βελτιστοποιεί την πολυφασματική ανάλυση της υψίσυχνης (≥20Hz) γ-ταλαντωτικής δραστηριότητας. Αυτή η δοκιμασία οπτικογνωστικής κατηγοριοποίησης λαμβάνει χώρα τόσο σε νορμοξαιμικές όσο και υποξαιμικές συνθήκες (ελεγχόμενη μείωση στον κορεσμό του αίματος σε οξυγόνο από ≥97% γύρω στο 80% για 15 λεπτά κάτω από συνθήκες υποβαρικής υποξίας μέσα σε υποβαρικό θάλαμο), προκειμένου να ελέγξουμε ηλεκτροφυσιολογικούς δείκτες που μπορούν να ανιχνεύσουν και να συλλάβουν με τον πιο ευαίσθητο και δυναμικό τρόπο ακόμη και τόσο βραχύβιες και σχετικά ήπιες μεταβολές της εγκεφαλικής λειτουργίας. Η στατιστική παραμετρική ανάλυση των χρονοφασματικών χαρτών και η γενικευμένη, στατιστικά πιο ασφαλής, μέθοδος ανάλυσης των διακυμάνσεων ανέδειξαν ως πλέον ευαίσθητους και αξιόπιστους τους ακόλουθους δείκτες: τις κύριες αιχμές των προκλητών δυναμικών, τον παράγοντα φασικής συνάφειας των ταλαντώσεων μεταξύ των μοναδιαίων καταγραφών και την εκλυόμενη ενέργεια των προκλητών/φασικά-κλειδωμένων και επαγόμενων/ολικών ταλαντώσεων. Οι ηλεκτροφυσιολογικοί αυτοί δείκτες σε συνδυασμό με ψυχομετρικές δοκιμασίες επιτρέπουν τη διερεύνηση των σταδίων/επιπέδων κάμψης καθώς και των αποθεμάτων αντιρρόπησης των οπτικο-αντιληπτικών και γνωστικών-νοητικών λειτουργιών του εγκεφάλου για τον καθορισμό των λειτουργικών ουδών ευαισθησίας διάφορων εγκεφαλικών λειτουργιών στην υποξία. Ανοίγουν μάλιστα το δρόμο. για το λειτουργικό χαρακτηρισμό, τη διάγνωση και την παρακολούθηση εγκεφαλικών προσβολών ή άλλων οξέων και χρόνιων παθολογικών καταστάσεων του εγκεφάλου.