A Scenario-Based Learning of Electrical Circuits

This paper presents a framework of an educational scenario for the teaching of electrical circuits at senior high schools. This scenario aims at the development of exploratory and critical thinking of students, the development of make-decision skills and knowledge transfer skills from one framework to another, the ability of collaboration and  in common approach of problem solving. During the lessons, the student teams discover the formulas and principles of the  total resistance, the voltage drop across the resistances, and the flowing current through the resistances, in series, in parallel, and in combination resistance circuits by comparing the circuits with each other and guided by the exploratory questions and scaffolding as well. At the end, the student teams solve an open-ended problem based upon their knowledge obtained through the activities. This framework has adopted and applied by educators with a great success. Keywords: Educational scenario, Problem solving, Social constructivism, Cooperative learning

On the Complexity of Dynamic Mechanism Design

We introduce a dynamic mechanism design problem in which the designer wants to offer for sale an item to an agent, and another item to the same agent at some point in the future. The agent's joint distribution of valuations for the two items is known, and the agent knows the valuation for the current item (but not for the one in the future). The designer seeks to maximize expected revenue, and the auction must be deterministic, truthful, and ex post individually rational. The optimum mechanism involves a protocol whereby the seller elicits the buyer's current valuation, and based on the bid makes two take-it-or-leave-it offers, one for now and one for the future. We show that finding the optimum deterministic mechanism in this situation - arguably the simplest meaningful dynamic mechanism design problem imaginable - is NP-hard. We also prove several positive results, among them a polynomial linear programming-based algorithm for the optimum randomized auction (even for many bidders and periods), and we show strong separations in revenue between non-adaptive, adaptive, and randomized auctions, even when the valuations in the two periods are uncorrelated. Finally, for the same problem in an environment in which contracts cannot be enforced, and thus perfection of equilibrium is necessary, we show that the optimum randomized mechanism requires multiple rounds of cheap talk-like interactions

Thermophoretic manipulation of the mechanical properties of biomaterials in microfluidics

The optimization of cell-substrate and cell-cell interactions is a central objective in tissue engineering applications. There is great potential to modulate and improve such interactions using extra cellular matrices that exhibit a gradient of mechanical properties that mimic accurately the in vivo tissue microenvironment and modulate cell behavior especially at the microscale. Here we show that by applying temperature gradients across a microfluidic channel and exploiting thermophoretic transport effects, it is possible to fabricate biocompatible hydrogels with controllable stiffness and porosity gradients. The elasticity of the hydrogels was evaluated locally by Atomic Force Microscopy revealing values between 20-100 kPa. The hydrogel microstructure was investigated by Scanning Electron Microscopy after supercritical drying and confirms the concentration gradient induced by thermophoresis. Moreover, we show that the stiffness gradient of the biomaterials can be effectively modulated by regulating the temperature difference across the microfluidic device and altering the concentration of gellan gum. Furthermore, the proliferation and level of mineralization of MC3T3 osteoblasts, seeded on the surface of the biomaterial, was monitored over time at different stiffness areas and time points, using live/dead assays and X-Ray Fluorescence technique. Cells show a preferential migration and proliferation towards the stiffer side where they also produce a higher mineralization (i.e., phosphorus and calcium deposits). Taken together, these results establish a new route to controlling the microstructure of cell culture matrices

A novel detrimental homozygous mutation in the WFS1 gene in two sisters from nonconsanguineous parents with untreated diabetes insipidus

Given the limited lifespan and with the recent progress in experimental treatments for WS, timely diagnosis and multidisciplinary treatment for DI/DM, hydronephrosis, and visual/psychiatric status-maintaining quality of life-are of crucial importance

Η γέννηση του καπιταλισμού στον Μαρξ και τον Βέμπερ

Αντικείμενο της διπλωματικής εργασίας είναι η γέννηση του καπιταλισμού. Το εν λόγω θέμα εξετάζεται από την οπτική της κοινωνικής θεωρίας, ενώ από τις πολλές δυνατές θεωρητικές προσεγγίσεις επιλέχθηκαν αυτές του Καρλ Μαρξ και του Μαξ Βέμπερ. Προτάσσεται η πραγμάτευση των διαφορετικών μεθοδολογικών επιλογών τους, διότι, παρότι δεν αποτελεί το κυρίως αντικείμενο της εργασίας, είναι αναγκαία για την ευχερέστερη κατανόηση των συγκεκριμένων αναλύσεων των δύο στοχαστών για τη γέννηση του καπιταλισμού. Στη συνέχεια παρουσιάζεται διεξοδικά αφενός η σχετική τοποθέτηση του Καρλ Μαρξ, η οποία χωρίζεται σε δύο ενότητες που αντιστοιχούν στην λογική και στην ιστορική στιγμή της ανάλυσής του, και αφετέρου εκείνη του Μαξ Βέμπερ, η οποία και αυτή διαιρείται σε δύο ενότητες, όπου εξετάζονται διαδοχικά α) ο ρόλος της προτεσταντικής ηθικής και β) η συμβολή ποικίλων άλλων κοινωνικών παραγόντων. Με βάση τα παραπάνω επιχειρήθηκε η σύγκριση των προσεγγίσεων τους για τη γέννηση του καπιταλισμού και διαπιστώθηκε η ύπαρξη μιας σχετικά εκτεταμένης συγγένειας μεταξύ τους. Ειδικότερα, φάνηκε πως η ανάλυση του Βέμπερ βασίστηκε σε μεγάλο βαθμό στην αντίστοιχη μαρξική· διαφώνησε σε ορισμένα σημεία της· επεξεργάστηκε και εκτίμησε διαφορετικά άλλα· τροποποίησε ορισμένα από αυτά· και κυρίως την εμπλούτισε διανοίγοντας νέες πτυχές του υπό εξέταση φαινομένου που έπρεπε να διερευνηθούν -και ως ένα βαθμό διερευνήθηκαν.The topic of this dissertation is the birth of capitalism. The issue is examined from the perspective of social theory, and out of numerous possible theoretical approaches it was the ones by Karl Marx and Max Weber that were chosen. It was deemed necessary to prioritize the two thinkers’ different methodological choices, because, despite not being the main subject of the study, it will facilitate understanding of their specific analyses of the birth of capitalism. What follows is a detailed account of Karl Marx's position, which is divided into two sections corresponding to the logical and historical moment of his analysis, and that of Max Weber’s, which is also divided into two sections, where the role of protestant ethic and the contribution of a variety of other social factors are discussed respectively. On the basis of the above, there has been an attempt to compare their approaches to the birth of capitalism and the existence of a relatively broad affinity was found between them. In particular, it appears that Weber's analysis was largely based on Marx’s; he disagreed on some points; elaborated upon and assessed some others; modified a number of them; and mainly enriched it by opening up new aspects of the phenomenon under consideration that had to be explored -and to some extent- were explored

Focal dystonia, tremor and myokymic discharges secondary to electrical injury

We describe the case of a male patient who developed electromyographically confirmed myokymia, dystonia and tremor and clinically confirmed focal dystonia and tremor, secondary to electrical injury. Dystonia is a rare complication of electrical injury. Myokymic discharges secondary to electrical injury are previously unreported. Dystonia and tremor EMG findings were present not only at the clinically affected muscles of the lower limb but also at the clinically unaffected upper limb muscles. This is the first case report to link myokymia as a secondary complication of an electrical injury

Bilateral De Quervain Syndrome after Aromatase Inhibitor Administration: A Case Report and Review of the Literature

Aromatase inhibitors are widely used as one of the main treatment options of both early and advanced hormone receptor-positive breast cancer in postmenopausal women. Unfortunately, musculoskeletal symptoms are often presented in patients treated with aromatase inhibitors (AIs), and, although the pathogenesis is unknown, postulated mechanisms have been described. Herein, to our knowledge, we present the first report of bilateral De Quervain syndrome related with AIs therapy with a review of the relevant literature

Quantitative determination of glycosaminoglycans in tears of diabetic patients

Marilita M Moschos1, Alexandros A Rouvas1, Spyridon Papadimitriou1, Athanasios Kotsolis1, Nikolaos Sitaras2, Michael Apostolopoulos11Department of Ophthalmology; 2Department of Pharmacology, University of Athens, GreecePurpose: To determine the amount of glycosaminoglycans (GAGs) in tears of patients with diabetic retinopathy (DR) and to compare it with normal subjects.Methods: 38 patients with DR and 24 normal volunteers were included. Thirty subjects suffered from background diabetic retinopathy (BDR) and 8 from proliferate diabetic retinopathy (PDR). For the GAGs assay, the uronic carbazole reaction was used.Results: The mean concentration of GAGs was significantly higher in patients with DR than in normal subjects. The GAGs concentration in patients with BDR or PDR was significantly higher than in normal subjects.Conclusion: The measurement of GAGs in tears of diabetic patients could be a tool in order to assess the stability or not of the disease.Keywords: glycosaminoglycans, tears, diabetic retinopath

Diving as a Scientist: Training, Recognition, Occupation - The “Science Diver” Project

Conducting scientific work underwater is a challenging endeavor. From collecting samples to protecting underwater cultural heritage sites scientific divers need to address issues concerning scientific methodology, diving safety, professional acknowledgement, training, legal implications etc. All of these matters are handled in different ways depending on factors like region, organizations involved, legal framework, diving philosophy etc. producing a diverse framework on scientific diving as a distinct type of underwater work. The ScienceDIVER project’s main objective is to study and analyze this fragmented landscape, in order to provide insight and suggestions towards a commonly accepted framework that will promote scientific diving as a means of forwarding knowledge both within the scientific community and its interaction with the public