Spectroscopic EPR and IR studies of monomeric and dimeric species formed upon adsorption of nitric oxide on Ce0.75Zr0.25O2 and their reactivity with dioxygen

The interaction of nitric oxide with Ce_0.75Zr_0.25O₂ solid solution were investigated by means of EPR and IR spectroscopies. The influence of adsorption parameters such as adsorption temperature and pressure, presence of the O₂ co-reactant on the nature and relative surface abundance of the resultant mono- and dimeric NO species was elucidated. The thermal stability of the surface nitrosyl complexes and their reactivity toward dioxygen were also examined.     

Alteration of substrate specificity of cholesterol oxidase from Streptomyces sp. by site-directed mutagenesis

Despite the structural similarities between cholesterol oxidasefrom Streptomyces and that from Brevibacterium, both enzymesexhibit different characteristics, such as catalytic activity,optimum pH and temperature. In attempts to define the molecularbasis of differences in catalytic activity or stability, substitutionsat six amino acid residues were introduced into cholesteroloxidase using site-directed mutagenesis of its gene. The aminoacid substitutions chosen were based on structural comparisonsof cholesterol oxidases from Streptomyces and Brevibacterium.Seven mutant enzymes were constructed with the following aminoacid substitutions: L117P, L119A, L119F, V145Q, Q286R, P357Nand S379T. All the mutant enzymes exhibited activity with theexception of that with the L117P mutation. The resulting V145Qmutant enzyme has low activities for all substrates examinedand the S379T mutant enzyme showed markedly altered substratespecificity compared with the wild-type enzyme. To evaluatethe role of V145 and S379 residues in the reaction, mutantswith two additional substitutions in V145 and four in S379 wereconstructed. The mutant enzymes created by the replacement ofV145 by Asp and Glu had much lower catalytic efficiency forcholesterol and pregnenolone as substrates than the wild-typeenzyme. From previous studies and this study, the V145 residueseems to be important for the stability and substrate bindingof the cholesterol oxidase. In contrast, the catalytic efficiencies(k_cat/K_m) of the S379T mutant enzyme for cholesterol and pregnenolonewere 1.8- and 6.0-fold higher, respectively, than those of thewild-type enzyme. The enhanced catalytic efficiency of the S379Tmutant enzyme for pregnenolone was due to a slightly high k_catvalue and a low K_m value. These findings will provide severalideas for the design of more powerful enzymes that can be appliedto clinical determination of serum cholesterol levels and assterol probes.     

Monte Carlo simulation of radiation-induced solid state polymerization

A Monte Carlo method was used for a computer simulation of radiation-induced solid state polymerization. The propagation of polymer chains was simulated by means of self-avoiding random walks on a tetrahedral lattice. The initiation and termination of the chains were modelled by pseudorandom processes. The influence of conditions of the in-source process on the post-polymerization kinetics and on the degree of polymerization of the polymers was studied.     

Quality assessment for a visual and automatic license plate recognition

Video transmission and analysis is often utilized in applications outside of the entertainment sector, and generally speaking this class of video is used to perform specific tasks. Examples of these applications include security and public safety. The Quality of Experience (QoE) concept for video content used for entertainment differs significantly from the QoE of surveillance video used for recognition tasks. This is because, in the latter case, the subjective satisfaction of the user depends on achieving a given functionality. Recognizing the growing importance of video in delivering a range of public safety services, we focused on developing critical quality thresholds in license plate recognition tasks based on videos streamed in constrained networking conditions. Since the number of surveillance cameras is still growing it is obvious that automatic systems will be used to do the tasks. Therefore, the presented research includes also analysis of automatic recognition algorithms.     

Eliminability of cut in hypersequent calculi for some modal logics of linear frames

Hypersequent calculi, introduced independently by Pottinger and Avron, provide a powerful generalization of ordinary sequent calculi. In the paper we present a proof of eliminability of cut in hypersequent calculi for three modal logics of linear frames: K4.3, KD4.3 and S4.3. Our cut-free calculus is based on Avron's HC formalization for Gödel–Dummett's logic. The presented proof of eliminability of cut is purely syntactical and based on Ciabattoni, Metcalfe, Montagna's proof of eliminability of cut for hypersequent calculi for some fuzzy logics with modalities.     

Discrete time sliding mode control with reduced switching – a new reaching law approach

In this paper, a novel reaching law for discrete‐time variable structure systems is proposed. It ensures that the representative point (state) of the controlled plant approaches the switching plane in finite time and then crosses it in every subsequent step. Moreover, the proposed reaching law ensures that for the nominal plant the absolute value of the sliding variable asymptotically decreases to zero, and for the perturbed plant, it converges to a smaller interval around zero than with the application of previously proposed reaching laws. The control method proposed in this paper guarantees asymptotic stability of the nominal system and uniform ultimate boundedness of the perturbed one. Furthermore, the method ensures that the sliding variable rate of change (i.e. the difference between its values at any two subsequent sampling instants) is bounded by design parameters, which do not depend on the system initial conditions. This is a highly desirable property, as it results in a priori specified, ‘almost’ constant convergence rate of the sliding variable when the system state is far off the switching plane and helps enforce state constraints in the system. Copyright © 2014 John Wiley & Sons, Ltd.     

INSIGMA: an intelligent transportation system for urban mobility enhancement

Intelligent Transportation Systems (ITS) aim to improve safety, mobility and environmental performance of road transport. The INSIGMA project provides a fresh look at the possible innovations in this field, by enhancing the functionality and accuracy of ITS in urban environments. This paper describes the architecture, sensors, processing algorithms, output modules and advantages of the developed system. A comparison of existing ITS systems has been provided as background. Special attention has been given to performance and privacy issues, as the system includes social aspects such as location monitoring.