Impact of transduction scaling laws on nanoelectromechanical systems

We study the electromechanical transduction in nanoelectromechanical actuators and show that the differences in scaling for electrical and mechanical effects lead to an overall non-trivial scaling behavior. In particular, the previously neglected fringing fields considerably increase electrical forces and improve the stability of nanoscale actuators. This shows that electrostatics does not pose any limitations to downscaling of electromechanical systems, in fact in several respects, nanosystems outperform their microscale counterparts. As a specific example, we consider in-plane actuation of ultrathin slabs and show that devices consisting of a few layers of graphene are feasible, implying that electromechanical resonators operating beyond 40 GHz are possible with currently available technology

Chelator-free/chelator-mediated radiolabeling of colloidally stabilized iron oxide nanoparticles for biomedical imaging

The aim of this study was to develop a bioimaging probe based on magnetic iron oxide nanoparticles (MIONs) surface functionalized with the copolymer (p(MAA-g-EGMA)), which were radiolabeled with the positron emitter Gallium-68. The synthesis of the hybrid MIONs was realized by hydrolytic condensation of a single ferrous precursor in the presence of the copolymer. The synthesized MagP MIONs displayed an average D-h of 87 nm, suitable for passive targeting of cancerous tissues through the enhanced permeation and retention (EPR) effect after intravenous administration, while their particularly high magnetic content ascribes strong magnetic properties to the colloids. Two different approaches were explored to develop MIONs radiolabeled with Ga-68: the chelator-mediated approach, where the chelating agent NODAGA-NHS was conjugated onto the MIONs (MagP-NODAGA) to form a chelate complex with Ga-68, and the chelator-free approach, where Ga-68 was directly incorporated onto the MIONs (MagP). Both groups of NPs showed highly efficient radiolabeling with Ga-68, forming constructs which were stable with time, and in the presence of PBS and human serum. Ex vivo biodistribution studies of [Ga-68]Ga- MIONs showed high accumulation in the mononuclear phagocyte system (MPS) organs and satisfactory blood retention with time. In vivo PET imaging with [Ga-68]Ga-MagP MIONs was in accordance with the ex vivo biodistribution results. Finally, the MIONs showed low toxicity against 4T1 breast cancer cells. These detailed studies established that [Ga-68]Ga- MIONs exhibit potential for application as tracers for early cancer detection.Web of Science117art. no. 167

Inmate cancer patients – highlighting the importance of a holistic approach to oncological care

Purpose: Inmate oncologic patients' rates increased drastically worldwide. Elderly, limited exercise, unhealthy diet, hepatitis, HIV+ status, tobacco and alcohol use, constitute the main cancer risk factors. We present an outline of practical oncological management and ethical thinking, in the specific environment of a detention facility. Methods: PubMed, Cochrane Database of Controlled Trials, SCOPUS and grey literature were extensively searched upto October 2021. Ιncarcerated oncologic patients experiencevarious everyday challenges:their confinement in high securityfacilities, the lack of access to critical care and related ethicaldilemmas inherent to the context of a correctional facility. Results: The detention facilities may be inadequate in providing early cancer diagnosis and appropriate care mainlydue to a lack of specialized personnel, b) in-house or in external specialized cancer hospitals, care variability (e.g. admissions in small local or regional hospitals), c) delays inproviding access and d) gatekeeper systems. There is a paucity of administration of a) systemic therapy(chemotherapy, targeted drug therapy etc), b) radiotherapy, c)palliative care, and d) enrollment in clinical trials.  Conclusions: Correctional facilities must encourage teamwork between healthcare and correctional professionals inorder to improve the provided anticancer care

Nitrosative and Oxidative Stresses Contribute to Post-Ischemic Liver Injury Following Severe Hemorrhagic Shock: The Role of Hypoxemic Resuscitation

Purpose: Hemorrhagic shock and resuscitation is frequently associated with liver ischemia-reperfusion injury. The aim of the study was to investigate whether hypoxemic resuscitation attenuates liver injury. Methods: Anesthetized, mechanically ventilated New Zealand white rabbits were exsanguinated to a mean arterial pressure of 30 mmHg for 60 minutes. Resuscitation under normoxemia (Normox-Res group, n = 16, PaO2 = 95–105 mmHg) or hypoxemia (Hypox-Res group, n = 15, PaO 2 = 35–40 mmHg) followed, modifying the FiO 2. Animals not subjected to shock constituted the sham group (n = 11, PaO 2 = 95–105 mmHg). Indices of the inflammatory, oxidative and nitrosative response were measured and histopathological and immunohistochemical studies of the liver were performed. Results: Normox-Res group animals exhibited increased serum alanine aminotransferase, tumor necrosis factor- alpha, interleukin (IL)-1b and IL-6 levels compared with Hypox-Res and sham groups. Reactive oxygen species generation, malondialdehyde formation and myeloperoxidase activity were all elevated in Normox-Res rabbits compared with Hypox-Res and sham groups. Similarly, endothelial NO synthase and inducible NO synthase mRNA expression was up-regulated and nitrotyrosine immunostaining increased in animals resuscitated normoxemically, indicating a more intense nitrosative stress. Hypox-Res animals demonstrated a less prominent histopathologic injury which was similar to sham animals. Conclusions: Hypoxemic resuscitation prevents liver reperfusion injury through attenuation of the inflammatory respons

Globalisation and the Executive Committee: Reflections on the Contemporary Capitalist State

I touch very briefly on four specific points. First, the question of the precipitous decline, or even structural impossibility, of a 'national bourgeoisie' capable of retaining a relatively autonomous basis of capital accumulation, and of the new resulting internal equilibria in the dominant power blocks. Second, the growing fragmentation of the labouring population into numerous, mobile, differentiated and largely antagonistic fractions, with all that this implies for the process of dislocation and disorganisation of traditional forms of class struggle. Third, the new functions of the capitalist state which, in its increasingly authoritarian form, assumes overall reproductive responsibility by means of a growing regulation of the deregulation process. This is generating an unprecedented fusion, or confusion, of the state's economic and ideological functions. Fourth, the new developing forms of articulation between the various state apparatuses and the professional political personnel occupying their summits, on the one hand, and the representatives of big capital on the other

Η αλληλεπίδραση μεταξύ χρηματοοικονομικού κινδύνου και κρατικού κινδύνου για τον οικονομικό κύκλο στην Ευρωζώνη

We develop a dynamic stochastic general equilibrium model to study the role of the interdependence between financial intermediation and sovereign crises for economic activity and policy. The model is a synthesis of the leading, modern approaches in the literature of financial frictions and sovereign default. In particular, we model financial frictions following Bernanke et al. (1999) and we model the event of sovereign default, using the stochastic fiscal limit concept of Bi and Traum (2012). We find that an increase in capital investment risk, (risk shock), results in a considerably deeper recession, when sovereign risk is also present. The recession strongly depends on the government’s countercyclical financial sector rescues policy. An increase in capital investment risk raises government expenditures, which in turn raise debt. The increase in debt increases the probability of government default, which results in higher interest rates on bonds and bank deposits. The higher interest rates, working through the financial accelerator mechanism, further deepen the recession. This result has three policy implications. First, Euro Area policies dealing with failing banks aggravated the recession. Second, although there has been a supranational effort with the creation of the EFSF/ESM to provide loans to sovereigns, as long as there is no direct mechanism for financial sector rescues, Euro Area policies continue to exacerbate the recession. Third, in favor of austerity measures used in the EA, we find that government spending multipliers are smaller in the presence of sovereign risk.Αναπτύσσουμε ένα νεο-κεϋνσιανό (newKeynesian - ΝΚ) στοχαστικό δυναμικό μοντέλο γενικής ισορροπίας (dynamicstochasticgeneralequilibrium – DGSE) για να μελετήσουμε το ρόλο που έχει στον οικονομικό κύκλο η αλληλεξάρτηση μεταξύ της χρηματοοικονομικής διαμεσολάβησης (financial intermediation) και του κρατικού κινδύνου (sovereignrisk). Το μοντέλο μας συνθέτει τις κυρίαρχες σύγχρονες προσεγγίσεις σε δύο κατευθύνσεις της βιβλιογραφίας: των χρηματοοικονομικών τριβών (financial frictions) και του κινδύνου κρατικής πτώχευσης (sovereigndefault). Συγκεκριμένα, μοντελοποιούμε τις χρηματοοικονομικέςτριβές σύμφωνα με τους Bernanke κ.ά. (1999) και την πιθανότητα της κρατικής πτώχευσης χρησιμοποιώντας την ιδέα του στοχαστικού δημοσιονομικού ορίου των Bi και Traum (2012). Καταλήγουμε δε ότι, εφόσον υπάρχουν αλληλεπιδράσεις χρηματοοικονομικής διαμεσολάβησης και κρατικού κινδύνου, τότε μία αύξηση στον κίνδυνο της κεφαλαιακής επένδυσης (διαταραχή του επιπέδου κινδύνου), η οποία πηγάζει από τον χρηματοπιστωτικό τομέα, έχει ως αποτέλεσμα μία σημαντικά βαθύτερη ύφεση. Η ύφεση εξαρτάται σημαντικά από την προκυκλική/αντικυκλική πολιτική της κυβέρνησης σχετικά με τα απαιτούμενα κεφάλαια που διακρατεί για το πιθανό κόστος της διάσωσης του χρηματοπιστωτικού τομέα. Το παραπάνω αποτέλεσμα οδηγεί στα παρακάτω συμπεράσματα οικονομικής πολιτικής. Οι ευρωπαϊκές πολιτικές για τη διάσωση του χρηματοοικονομικού συστήματος έχουν χειροτερέψει την ύφεση. Εάν δεν υπάρξει κεντρικός ευρωπαϊκός μηχανισμός στα πλαίσια του EFSF/ESM που να χρηματοδοτεί απευθείας το τραπεζικό σύστημα το πρόβλημα θα εξακολουθεί να υπάρχει. Ο πολλαπλασιαστής των κρατικών δαπανών είναι μικρότερος όταν υπάρχει κρατικός κίνδυνος ευνοώντας πολιτικές οικονομικής λιτότητας

Methods for the simulation of buildings thermal behaviour and related case studies

158 σ.Προσομοίωση της θερμικής συμπεριφοράς ενός κτιρίου με χρήση πεπερασμένων διαφορών.Analysis of thermal behaviour of buildings using the finite difference method.Κωνσταντίνος Θ. Τσουκαλά

oι RHo GTPάσες στην παθοφυσιολογία και θεραπεία του καρκίνου

Rho GTPases, a prominent member of the RAS proteins family, function as molecular switches regulating fundamental biological processes in all eukaryotic cells, by modifying cell response on different molecular signalling pathways. Unlike the majority of RAS oncogenes, mutant forms of these proteins are rarely found. Nonetheless switching between the active GTP-bound forms to the inactive GDP forms, are additionally facilitated by a different set of molecules known as GEFs, GAPs and GDIs, whose deregulation is widely associated with the cancer phenotype. Principally, early research involved them in actions pertinent to cytoskeletal dynamics, cell polarity, focal adhesion and vesicle trafficking. However, recent evidence underpins the contribution of their aberrant expression in acquiring distinct hallmarks governing tumorigenesis, on top of premature assumptions on metastatic potential, like replicating immortality, apoptotic resistance and angiogenesis.Oι Rho GTPάσες αποτελούν ευρέως μελετημένα μέλη της υπεροικογένειας των Ras πρωτεϊνών. Λειτουργούν ως μοριακοί διακόπτες, ρυθμίζοντας θεμελιώδεις βιολογικές διεργασίες σε όλα τα ευκαρυωτικά κύτταρα, μετά από τροποποίηση της κυτταρικής απόκρισης σε διαφορετικές μοριακές οδούς σηματοδότησης. Σε αντίθεση με την πλειοψηφία των ογκογονιδίων Ras, σπανίως ευρίσκονται μεταλλαγμένα στελέχη των πρωτεϊνών αυτών. Εντούτοις η εναλλαγή μεταξύ ενεργού και ανενεργού μορφής, με την αντικατάσταση του GTP από GDP αντίστοιχα στο μόριό τους, διευκολύνεται από μία πρόσθετη σειρά μορίων γνωστών ως GEFs, GAPs και GDIs, των οποίων η απορρύθμιση έχει συσχετιστεί με τον καρκινικό φαινότυπο. Σε πρώιμα ερευνητικά ευρήματα η λειτουργία τους συσχετίστηκε κυρίως με την δυναμική αναδιοργάνωση του κυτταροσκελετού, την κυτταρική πολικότητα, την εστιασμένη προσκόλληση και την ενδοκυττάρια διακίνηση κυστιδίων. Ωστόσο, πέραν των πρώιμων υποθέσεων περί της συμβολής της άτυπης έκφρασής τους στη μετάσταση, στον ανεξέλεγκτο κυτταρικό πολλαπλασιασμό, στους αντι-αποπτωτικούς μηχανισμούς και στη νεοαγγειογένεση, πρόσφατα στοιχεία επισημαίνουν τη συμβολή αυτή κυρίως στην απόκτηση ιδιαίτερων χαρακτηριστικών που διέπουν την καρκινογένεση

Physics-Informed Neural Network Solution of Point Kinetics Equations for a Nuclear Reactor Digital Twin

A digital twin (DT) for nuclear reactor monitoring can be implemented using either a differential equations-based physics model or a data-driven machine learning model. The challenge of a physics-model-based DT consists of achieving sufficient model fidelity to represent a complex experimental system, whereas the challenge of a data-driven DT consists of extensive training requirements and a potential lack of predictive ability. We investigate the performance of a hybrid approach, which is based on physics-informed neural networks (PINNs) that encode fundamental physical laws into the loss function of the neural network. We develop a PINN model to solve the point kinetic equations (PKEs), which are time-dependent, stiff, nonlinear, ordinary differential equations that constitute a nuclear reactor reduced-order model under the approximation of ignoring spatial dependence of the neutron flux. The PINN model solution of PKEs is developed to monitor the start-up transient of Purdue University Reactor Number One (PUR-1) using experimental parameters for the reactivity feedback schedule and the neutron source. The results demonstrate strong agreement between the PINN solution and finite difference numerical solution of PKEs. We investigate PINNs performance in both data interpolation and extrapolation. For the test cases considered, the extrapolation errors are comparable to those of interpolation predictions. Extrapolation accuracy decreases with increasing time interval