“Wrapping” X3DOM around Web Audio API

Spatial sound has a conceptual role in the Web3D environments, due to highly realism scenes that can provide. Lately the efforts are concentrated on the extension of the X3D/ X3DOM through spatial sound attributes. This paper presents a novel method for the introduction of spatial sound components in the X3DOM framework, based on X3D specification and Web Audio API. The proposed method incorporates the introduction of enhanced sound nodes for X3DOM which are derived by the implementation of the X3D standard components, enriched with accessional features of Web Audio API. Moreover, several examples-scenarios developed for the evaluation of our approach. The implemented examples established the achievability of new registered nodes in X3DOM, for spatial sound characteristics in Web3D virtual worlds

Υπερέκφραση, καθαρισμός και χαρακτηρισμός μίας θερμόφιλης β-φωσφογλυκοζιδάσης από το Geobacillus sp. και παραγωγή καθαρών φωσφορυλιωμένων υποστρωμάτων

Το ένζυμο β-Ρ-γλυκοζιδάση (EC 3.2.1.86) είναι ένα σημαντικό μέλος της οικογένειας των γλυκοζιδικών υδρολασών GH1, με λειτουργία την υδρόλυση των β-(1,4)-γλυκοζιδικών δεσμών σε φωσφορυλιωμένα υποστρώματα. Η δράση του εξαρτάται από το βακτηριακό σύστημα μεταφοράς υδατανθράκων PEP:PTS (PhososphoEnolPyruvate: PhosphoTranspherase System), το οποίο ευθύνεται για την πρόσληψη και ταυτόχρονη φωφορυλίωση πλήθους εξωκυτταρικών ολιγοσακχαριτών. Για τη διεξαγωγή του βιοχημικού χαρακτηρισμού του ενζύμου, πραγματοποιήθηκε βιοσύνθεση και καθαρισμός φωσφορυλιωμένων δισακχαριτών, οι οποίοι χρησιμοποιήθηκαν ως υποστρώματα της β-Ρ-γλυκοζιδάσης. Κατόπιν έγινε υπερέκφραση του γονιδίου μίας GH1 β-Ρ-γλυκοζιδάσης, η οποία είχε προηγουμένως απομονωθεί από θερμόφιλο στέλεχος του Geobacillus sp. και το τελικό προϊόν υπέστη διαδικασία καθαρισμού. Μέσω μετρήσεων της ενζυμικής ενεργότητας σε ένα εύρος θερμοκρασιών και pH, προσδιορίστηκε ως βέλτιστη θερμοκρασία δράσης αυτή των 65°C και η τιμή pH 6. Οι μελέτες θερμοκρασιακής σταθερότητας έδειξαν ότι το ένζυμο δεν διατηρεί την αρχική του ενεργότητα μετά από επώαση σε θερμοκρασία 65 °C για διάστημα μίας ώρας. Τέλος, διαπιστώθηκε ότι η προσθήκη πιθανών αναστολέων στο ενζυμικό διάλυμα δεν επέφερε σημαντική μείωση της ενζυμικής ενεργότητας.The enzyme 6-phospho-β-glucosidase (EC 3.2.1.86) from glycoside hydrolase family 1 (GH1), catalyzes the hydrolysis of β-(1,4)-linked phosphorylated compounds. The enzymatic function is closely dependent on the bacterial PEP:PTS system (PhososphoEnolPyruvate: PhosphoTranspherase System), which is responsible for the uptake and simultaneous phosphorylation of numerous extracellular oligosaccharides. Production and purification of phosphorylated disaccharides to be used as substrates, was the first step towards the characterization of a novel β-P-glucosidase isolated from a thermophilic strain of Geobacillus sp. Moreover, sufficient quantities of protein were obtained as a result of overexpression in recombinant E. coli strains and purification. The optimal conditions of the enzymatic reaction were determined by measurement of enzymatic activity in different temperatures and pH values. Thus, optimal enzyme activity was exhibited at 65 °C and pH 6. Thermal stability was also ascertained. Incubation of the enzymatic solution across a range of temperatures resulted in a substantial decrease in activity. However, no significant decrease was observed following the addition of inhibitors

Spatial Sound Rendering – A Survey

Simulating propagation of sound and audio rendering can improve the sense of realism and the immersion both in complex acoustic environments and dynamic virtual scenes. In studies of sound auralization, the focus has always been on room acoustics modeling, but most of the same methods are also applicable in the construction of virtual environments such as those developed to facilitate computer gaming, cognitive research, and simulated training scenarios. This paper is a review of state-of-the-art techniques that are based on acoustic principles that apply not only to real rooms but also in 3D virtual environments. The paper also highlights the need to expand the field of immersive sound in a web based browsing environment, because, despite the interest and many benefits, few developments seem to have taken place within this context. Moreover, the paper includes a list of the most effective algorithms used for modelling spatial sound propagation and reports their advantages and disadvantages. Finally, the paper emphasizes in the evaluation of these proposed works

Scene integration for online VR advertising clouds

This paper presents a scene composition approach that allows the combinational use of standard three dimensional objects, called models, in order to create X3D scenes. The module is an integral part of a broader design aiming to construct large scale online advertising infrastructures that rely on virtual reality technologies. The architecture addresses a number of problems regarding remote rendering for low end devices and last but not least, the provision of scene composition and integration. Since viewers do not keep information regarding individual input models or scenes, composition requires the consideration of mechanisms that add state to viewing technologies. In terms of this work we extended a well-known, open source X3D authoring tool

Scene Integration for Online VR Advertising Clouds

This paper presents a scene composition approach that allows the combinational use of standard three dimensional objects, called models, in order to create X3D scenes. The module is an integral part of a broader design aiming to construct large scale online advertising infrastructures that rely on virtual reality technologies. The architecture addresses a number of problems regarding remote rendering for low end devices and last but not least, the provision of scene composition and integration. Since viewers do not keep information regarding individual input models or scenes, composition requires the consideration of mechanisms that add state to viewing technologies. In terms of this work we extended a well-known, open source X3D authoring tool

“Wrapping” X3DOM around Web Audio API

Spatial sound has a conceptual role in the Web3D environments, due to highly realism scenes that can provide. Lately the efforts are concentrated on the extension of the X3D/ X3DOM through spatial sound attributes. This paper presents a novel method for the introduction of spatial sound components in the X3DOM framework, based on X3D specification and Web Audio API. The proposed method incorporates the introduction of enhanced sound nodes for X3DOM which are derived by the implementation of the X3D standard components, enriched with accessional features of Web Audio API. Moreover, several examples-scenarios developed for the evaluation of our approach. The implemented examples established the achievability of new registered nodes in X3DOM, for spatial sound characteristics in Web3D virtual worlds