A Wind Turbine Tower Design Based on the Use of Fibre-Reinforced Composites.

Abstract not availableJRC.G-Institute for the Protection and the Security of the Citizen (Ispra

Dynamic Motions of the HIV-1 Frameshift Site RNA

The HIV-1 frameshift site (FS) plays a critical role in viral replication. During translation, the HIV-1 FS transitions from a 3-helix to a 2-helix junction RNA secondary structure. The 2-helix junction structure contains a GGA bulge, and purine-rich bulges are common motifs in RNA secondary structure. Here, we investigate the dynamics of the HIV-1 FS 2-helix junction RNA. Interhelical motions were studied under different ionic conditions using NMR order tensor analysis of residual dipolar couplings. In 150 mM potassium, the RNA adopts a 43°(±4°) interhelical bend angle (β) and displays large amplitude, anisotropic interhelical motions characterized by a 0.52(±0.04) internal generalized degree of order (GDOint) and distinct order tensor asymmetries for its two helices (η = 0.26(±0.04) and 0.5(±0.1)). These motions are effectively quenched by addition of 2 mM magnesium (GDOint = 0.87(±0.06)), which promotes a near-coaxial conformation (β = 15°(±6°)) of the two helices. Base stacking in the bulge was investigated using the fluorescent purine analog 2-aminopurine. These results indicate that magnesium stabilizes extrahelical conformations of the bulge nucleotides, thereby promoting coaxial stacking of helices. These results are highly similar to previous studies of the HIV transactivation response RNA, despite a complete lack of sequence similarity between the two RNAs. Thus, the conformational space of these RNAs is largely determined by the topology of their interhelical junctions

Modeling Space Market Dynamics : An Illustration Using Panel Data for US Retail

Peer reviewedPostprin

Association between adolescent idiopathic scoliosis prevalence and age at menarche in different geographic latitudes

BACKGROUND: Age at menarche is considered a reliable prognostic factor for idiopathic scoliosis and varies in different geographic latitudes. Adolescent idiopathic scoliosis prevalence has also been reported to be different in various latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to investigate a possible association between prevalence of adolescent idiopathic scoliosis and age at menarche among normal girls in various geographic latitudes. An attempt is also made to implicate a possible role of melatonin in the above association. MATERIAL-METHODS: 20 peer-reviewed published papers reporting adolescent idiopathic scoliosis prevalence and 33 peer-reviewed papers reporting age at menarche in normal girls from most geographic areas of the northern hemisphere were retrieved from the literature. The geographic latitude of each centre where a particular study was originated was documented. The statistical analysis included regression of the adolescent idiopathic scoliosis prevalence and age at menarche by latitude. RESULTS: The regression of prevalence of adolescent idiopathic scoliosis and age at menarche by latitude is statistically significant (p < 0.001) and are following a parallel declining course of their regression curves, especially in latitudes northern than 25 degrees. CONCLUSION: Late age at menarche is parallel with higher prevalence of adolescent idiopathic scoliosis. Pubarche appears later in girls that live in northern latitudes and thus prolongs the period of spine vulnerability while other pre-existing or aetiological factors are contributing to the development of adolescent idiopathic scoliosis. A possible role of geography in the pathogenesis of idiopathic scoliosis is discussed, as it appears that latitude which differentiates the sunlight influences melatonin secretion and modifies age at menarche, which is associated to the prevalence of idiopathic scoliosis

Space environment effects on equipment and structures—current and future technologies

The space environment is extremely hostile to the spacecraft but also to the equipment it carries. The materials which are used to the external side of the spacecraft, the solar panels, the sensors, and the electronics circuits, suffer greatly from their exposure to it. Extreme temperatures, ultraviolet radiation, ionizing radiation from solar proton events and cosmic rays, atomic oxygen in LEO, as well as collisions with micrometeoroids and space debris are factors that degrade the stuff, multiply the mission cost, and increase the risk. Therefore, the state-of-art of material technology is needed. In this study, a set of materials and technologies are presented, which reduce the above-mentioned risks. Extreme temperatures, ultra-vacuum, atomic oxygen, and high-energy radiation including particles as well as energy sources (X- and gamma rays) are potential extreme exposure conditions. Testing and qualification of materials exposed to these extreme conditions is a difficult task, to enable the design and manufacturing of high-endurance reliable components to be used in the world’s most sophisticated satellite and spacecraft components, as well as in future endeavors into the vicinity of the Solar System. © The Author(s) 2021

Design of a metal commercial building with full body beams

75 σ.Αντικείμενο της διπλωματικής εργασίας αποτελεί η εναλλακτική μελέτη ενός υφιστάμενου μεταλλικού εμπορικού κτηρίου. Το κτήριο μελετήθηκε με ολόσωμες δοκούς, ενώ έχει κατασκευαστεί με δικτυώματα. Κύριος σκοπός της εργασίας είναι η ενασχόληση και εμβάθυνση στη διαδικασία σχεδιασμού - ανάλυσης και διαστασιολόγησης - ενός μεγάλου έργου με φέροντα οργανισμό από χάλυβα. Ο σχεδιασμός πραγματοποιήθηκε με βάση τους Ευρωκώδικες (Ευρωκώδικας 1 και 3) και τον Ελληνικό Αντισεισμικό Κανονισμό.The subject of this essay is the alternative study of an existing metal building. The building has been studied with full body beams instead of metal grid. The main purpose of this essay is the understanding of the design that refers to a stucture with metal load bearing system. The design took place with Eurocodes (Eurocode 1 and 3) and the Greek National Code for Earthquakes.Παναγιώτης Δ. Μουζάκη

Distributed system intelligent design

As the importance of Distributed Systems is rapidly increasing and relevant applications become more demanding, optimal design of Distributed Systems becomes a critical issue. Distributed System design is not a trivial task, since various parameters influencing the overall performance of the system have to be considered. For the successful integration of Distributed System components knowledge from different areas must be combined leading to increasing complexity. In this paper is presented the recent research work undertaken by the authors towards the development of an intelligent tool for designing Distributed Systems. Methodologies from the Artificial Intelligent domain are integrated within our research framework in order to propose alternatives solutions for the Distributed System architecture. © Springer-Verlag Berlin Heidelberg 1994