Category Archives: Seminars

Tuesday 19 February 2019 16:00 – 17:00 Seminar Room 1

Dr. Nasos Argyriou Institute of Mediterranean Studies (IMS)

Abstract
The determination of geomorphology plays an important role in archaeological landscape research. Several landform types can be distinguished by characteristic geomorphic attributes that portray the surrounding landscape of a settlement and evaluate its geographical importance in terms of its ability to sustain a population. Various geoinformatic approaches are acknowledged, by using the freely available ASTER G-DEM, to provide valuable knowledge regarding the interfered processes shaping landscapes. The locations of archaeological settlements and the characterization of the dominant surrounding landscape geomorphometrics can reveal insights into the development of settlements and provide a better understanding of human behavior, with regard the landscape characteristics over time, such as the water management. In order to assess the best routes for water resources reaching the major settlements a multi-disciplinary approach within a Geographical Information Systems (GIS) environment is acknowledged by using integrated Multi-Criteria Decision Analysis (MCDA) and Least-Cost Path Analysis (LCPA). Such an approach proves to be a valuable tool for archaeologists to determine and evaluate the sustainability of the settlements and the water management planning in ancient periods.

Tuesday 29 January 2019 16:00 – 17:00 A. Payatakes Seminar Room

“On the Converse Problem for the Two-Component Gross-Pitaevskii System with a Large Coupling”

Dr. Christos Sourdis Institute of Applied and Computational Mathematics (IACM)

Abstract
Strongly coupled elliptic systems arise in the study of repulsive two-component Bose-Einstein condensates. In the strong competition (repulsion) limit, solutions that remain uniformly bounded are known to converge uniformly to a limiting profile whose components have disjoint supports wherein they satisfy limiting elliptic problems. Actually, their supports are separated by interfaces, across which the limiting profiles are merely Lipschitz continuous. In fact, the difference of these segregated components is a classical, sign-changing solution to a limiting scalar PDE. We will present the main known results and the state of the art, paying special emphasis on the blow-up limit problem near the interface and its linearization. We will then focus in the converse direction, that is whether solutions of the aforementioned limit scalar PDE problem can give rise to corresponding solutions of the coupled system for large values of the coupling parameter. Under natural linear nondegeneracy assumptions on a solution of the limit problem, we show that this is indeed the case in the radial setting. Our approach is perturbative, based on making rigorous formal matched asymptotics via a linearization procedure. Moreover, we provide fine estimates for the convergence to the corresponding solutions of the limit problems as the coupling parameter tends to infinity. This talk is based on a joint work with J-B. Casteras (Free University of Brussels).

Tuesday 18 December 2018 16:00 – 17:00 Seminar Room 1

“Systems Biology approach for the elucidation of system-wide p53dependent signaling pathways in Hodgkin and Non-Hodgkin lymphomas towards efficient therapeutic strategies”

Dr. Konstantina Psatha Institute of Molecular Biology and Biotechnology (IMBB)

Abstract
Lymphomas usually harbor a functionally inactive wild-type (wt) p53, promoting cell proliferation and survival, genomic instability and lymphoma resistance in therapy. Decoding the perturbed protein phosphorylation motifs contributing to lymphomagenesis is still required. The recently developed small molecule and p53-MDM2 antagonist, Nutlin-3a (N3a), induces a non-genotoxic reactivation of wtp53 protein, providing an excellent model system for the comprehensive understanding of p53 regulation, its effect on cell cycle arrest and apoptosis in lymphoma cells. In the present study, we used in vitro model lymphoma cell lines corresponding to different lymphoma subtypes +/- N3a for global comparative phosphoproteomic profiling, aiming to identify key phosphorylation events characteristic for every lymphoma (sub) type. The resulted datasets are being processed and evaluated by advanced bioinformatics tools, to conceptualize the first dynamic and detailed cell signaling map of lymphoma cells bearing a N3a-reactivated, offering detailed insights on the beneficial effect of N3a-mediated p53’s reactivation in the treatment of human lymphoma.

Tuesday 11 December 2018 16:00 – 17:00 Seminar Room 1

” Overcoming challenges of ancient DNA analysis ”

Dr. Nikolaos Psonis Institute of Molecular Biology and Biotechnology (IMBB)

Abstract
The past decade has witnessed a revolution in ancient DNA (aDNA) research. Although the focus of the field was previously limited to mitochondrial DNA and a few nuclear markers, whole genome sequences from the past can now be harnessed. This became possible via the massive sequence throughput of Next Generation Sequencing platforms and the ability to target short and degraded DNA molecules. Many ancient specimens previously unsuitable for DNA analyses because of extensive degradation can now successfully be used as source materials. Additionally, contamination issues that have haunted aDNA research for decades, particularly in human studies, can now be efficiently and confidently quantified. As such, the field of aDNA has entered the new era of genomics and has provided valuable information when testing specific hypotheses related to the past.

Tuesday 4 December 2018 16:00 – 17:00 Seminar Room 1

” Polarization-resolved second harmonic generation (P-SHG) imaging microscopy and applications”

Dr. Sotiris Psilodimitrakopoulos Institute of Electronic Structure and Laser (IESL)

Abstract
Traditionally, analysis of second harmonic generation (SHG) imaging has been achieved by evaluating the strength of the generated SHG signal, used for contrast. While non-linear signals intensities remain the “gold standard” for microscopists, this approach is inherently highly subjective, as the accuracy depends on the experience and skill of the interpreting scientist. There remains a clear need for quantitative, optical microscopy approaches that eliminate the artifacts inherent in the interpretation of SHG signal intensities. Towards that goal, we utilized polarization analysis of the SHG signals to probe the orientational information of the implicating SHG active assemblies. In particular, we upgraded a regular Zeiss fluorescence microscope into a fully-motorized polarization-resolved multi-photon microscope, using an Yb:KGW femtosecond laser, galvanometric mirrors and photomultiplier tubes, as well as retardation plates, analyzers, appropriate electronics, optics and filters1 (Fig.1). In this seminar, after introducing the raster-scanning imaging microscopy technique I will demonstrate how polarization-resolved SHG (P-SHG) imaging can be used for the detailed evaluation of crystal quality in 2D transition-metal dichalcogenide (TMD) materials as well as other applications of P-SHG imaging.

Tuesday 20 November 2018 16:00 – 17:00 A. Payatakes Seminar Room

“Innovation Management Policies in Greece during the 20th Century. Institutional Organization and Experts’ Contributions on Intellectual Property and Technical Standardization Issues.”

Spyros Tzokas, PhD, Institute for Mediterranean Studies (IMS)

Abstract
The presentation focuses on aspects of the policy management for the Intellectual Property and the Technical Standardization, highlighting the conditions that allowed (or even prevented) the production of a “primary” innovation in the Greek case. Since the early 20th century and until the Second War, the ways for the transition from the theory to practice for the advancements of industrial and business firms -according the moto ‘Industry-based-Science’- had been at the core of the expert’s debates in Greece and internationally. In the 1920s, after the end of the First War, under the pressure of the international conventions and as well as under an intensive protectionist trade policy, the Greek state, among others, established a legal system to regulate and rationalize the institutional context of the original/innovative ideas (inventions, patents, trademarks) in order foremost to protect and afterwards to internationalize the domestic production. At the same time, the local scientific and technical communities cooperated with the foreign scientific communities by were participating in international association’s debates on the definition of the technical units and standards to establish a common terminology in which they would integrate rationally the technical knowledges and practices for the normalization of an international system of standardization of the industrial methods and products. This process is emerged here by the emphasis on the endeavors and the initiatives of engineers, scientists and lawyers who contributed to these issues under the influences of a violent ideological, socioeconomic and cultural transformation of societies in Greece and abroad during the Interwar period.

Tuesday 13 November 2018 16:00 – 17:00 A. Payatakes Seminar Room

“The shipbuilding industry of Perama: labour and social labour reproduction”

Eleni Kyramargiou, PhD Institute for Mediterranean Studies (IMS)

Abstract
At the end of the 1960’s, the Piraeus Port Authority (PPA) transformed part of the coastal area of Perama in the Free Shipbuilding Zone. The establishment of this special shipyard which took on contract work in shipbuilding and maintenance by work sector, thus offering flexible but highlycompensated employment, led to the development of a whole network of professional relationships and activities which affected the evolution of the city of Perama on both the economic and the social level. The development of a mid-sized shipbuilding industry resulted in not only an increase in the businesses operating on the site, with foremen becoming business owners overnight, but also in employed personnel. More and more craftsmen, both qualified and unqualified, entered the workforce of the Zone. In 2008, the global shipping industry went through a period of great crisis which definitively affected the Greek shipping industry. This crisis was combined with the political and financial issues faced by the Skaramanga Shipyard; problems which remain unresolved until today, rendering the largest shipyard in the country inactive. In a short period of time, in effect all work in the Zone was interrupted, many businesses closed down permanently or temporarily, and thousands of workers were made redundant. In this context, the present talk will discuss issues related to labour in the shipbuilding industry. More specifically, we are going to discuss the subject of expertise in the different work sectors of the Zone, either through apprentice schools or through work itself, with the aim to highlight the process of social labour reproduction in the Zone during the last 50 years.

Tuesday 6 November 2018 16:00 – 17:00 Seminar Room 1

“Functional 3D Photonic Nanostructures Tuned for the Visible”

Dr. Ioanna Sakellari Institute of Electronic Structure and Laser (IESL)

Abstract
By coupling light with nanostructures many skills in controlling light have been achieved, most of which are impossible by bulk materials. A typical example of this type of novel artificially constructed materials is photonic crystals, i.e., a material that possesses a spatially periodic dielectric constant, which can strongly modulate electromagnetic waves and drive a photonic stopband; a frequency region where the propagation of light is forbidden. Depending on the dimensions of the photonic crystal, photonic stop-bands appear at different frequencies. Furthermore, utilizing the capabilities of modern nanotechnology, these interactions can be tailored at will depending on the material properties, the nanostructure geometry, and its surrounding. In this context, in the present talk, the synthesis of a novel active 3D printable hybrid material that can be employed for the fabrication of visible light active 3D photonic devices by combining twophoton direct laser writing and in situ synthesis of semiconductor nanoparticles will be discussed. In particular, it will be demonstrated experimentally how the two-in-one functional properties of the novel active nanocomposite material presented – namely high spatial resolution and high χ(3) nonlinear response, can be effectively utilized, firstly, to realize the visible light photonic band gap properties of 3D woodpile photonic crystals as clearly evidenced by the existence of pronounced photonic stop-bands and, secondly, to demonstrate, for the first time, evidence of ultrafast dynamic tuning of the photonic band gap properties in the visible. The work presented shows that the integration of active media and functional materials is a promising approach to the realization of active integrated photonics for visible light using high throughput technologies.

Thursday 1 November 2018 16:00 – 17:00 A. Payatakes Seminar Room

Dr. Georgia Antonopoulou Institute of Chemical Engineering Sciences (ICE-HT)

Abstract
Anaerobic digestion is a mature biological conversion process in which biomass is transformed into biogas, a mixture of methane and carbon dioxide. The process can be oriented towards dark fermentation, where hydrogen might be produced instead of methane, by controlling operational parameters such as the reactor pH and hydraulic retention time (HRT), inhibiting thus the methanogenesis. In this presentation, fermentative hydrogen production and anaerobic digestion of wastes /wastewaters or energy crops with readily fermentable sugars will be discussed. The factors affecting both processes will be analyzed and correlated with the main metabolites which are produced. In the sequel, the use of lignocellulosic biomass as feedstock for the production of secondgeneration biofuels, such as biohydrogen and biomethane will be considered. Lignocellulosic biomass consists of holocelluloses (cellulose, hemicellulose) and lignin, which vary quantitatively and qualitatively according to the plant material. The presence of lignin is apparently the most important factor affecting the biodegradability of lignocellulosic materials, although other factors such as the crystallinity of cellulose and the accessible surface area may also play an important role. Hence, in the present study, different pretreatment schemes will be analyzed for enhancing the yields and rates of biohydrogen and biomethane production from different kind of lignocellulosic materials.

Tuesday 23 October 2018 16:00 – 17:00 Seminar Room 1

“Geophysics for Archaeology” ..from the Fundamentals to Future Perspectives..

Dr. Melda KÜÇÜKDEMİRCİ Institute of Mediterranean Studies (IMS)

Abstract
Scientist from all around the world promoted an increasing specialization in geophysical survey techniques, data processing and interpretation that resulted in a well-defined discipline called Archaeological Geophysics and it is one of the most valuable tools in the hands of Archaeologists to define the physical and geometric properties of unseen buried structures under the ground. Development of data processing, image visualization techniques, 3D image display ways makes the researchers from other disciplines understand the geophysical data and results easier. Besides, qualitative and quantitative integration approaches are found very useful to achieve complementary and improved information about the buried archaeological target. Recently, the use of artificial intelligence for digital image processing has opened new research prospects also for geophysics. Especially automated image segmentation has become a very important task in today’s scenario for many disciplines as medicine, remote sensing so forth. Segmentation refers to the process of partitioning a digital image into multiple regions and representation of the image in that way is thought to be useful for objective analysis of geophysical maps during the interpretation. In this presentation, the applications of data integration approaches and first attempts on image segmentation approach by using artificial neural networks will be discussed.