Structure determination of a tetradecapeptide mimicking the RXVRG consensus sequence recognized by a Xenopus laevis skin endoprotease: An approach based on simulated annealing and 1H NMR

Summary The tetradecapeptide of sequence H-Asp-Val-Asp-Glu-Arg ⁵-Asp-Val-Arg-Gly⁹-Phe-Ala-Ser-Phe-Leu-NH₂ is recognized by a putative maturation endoprotease of the Xenopus laevis skin, which cleaves between Arg⁸ and Gly⁹. A conformational search has been performed on this peptide by simulated annealing calculations. Two different models in agreement with the NMR data were found. The conformational difference between the two types of model is located in the consensus sequence, i.e., from Arg⁵ to Gly⁹.     

Building cost effective lower layer VPNs: The ILEC/CLEC dilemma

Layer 2 and layer 1 Virtual Private Network (VPN) services; ranging from simple leased lines to extending private LANs across public networks, are commonplace today. With the continuously growing economic difficulties, capital meltdown, and telecommunication business turmoil, delivering those VPN services at the lowest cost or with the maximum revenue margin, while committing to Service Level Agreements (SLA), has become essential. We show that whether we tackle the optimal VPN design problem from an Incumbent Local Exchange Carrier (ILEC) standpoint or from a Competitive Local Exchange Carrier (CLEC) standpoint, we obtain contradictory rules. We show that by building Edge Disjoint VPN trees and spreading the traffic all over the network, the ILEC can achieve maximum throughput and enhanced network performance; while by concentrating all the VPN traffic over a single tree, the CLEC can minimize the cost of leased bandwidth. We then propose two simple algorithms that can help carriers and service providers leverage their networks and increase their revenue margins while meeting SLA requirements. Copyright © 2010 John Wiley & Sons, Ltd.     

The impact of point-to-multipoint traffic concentration onmultirate networks design

We consider the problem of multirate network design with point-to-multipoint communications. We give a mathematical formulation for this problem. Using approximations, we show that traffic concentration on a small number of links significantly reduces the cost of the network. We then propose a heuristic based on the traffic concentration principle to solve the network design problem approximately. Because this heuristic no longer requires advanced knowledge of demand matrices, we explain how it can be used as the basis for real-time design procedures. By means of numerical results, we show that this heuristic yields nearly optimal solutions     

Spatially Enhanced Bags of Visual Words Representation to Improve Traffic Signs Recognition

Traffic signs play a very vital role in safe driving and in avoiding accidents by informing the driver about the speed limits or possible dangers such as icy roads, imminent road works or pedestrian crossings. Considering the processing time and classification accuracy as a whole, a novel approach for visual words construction was presented, which takes the spatial information of keypoints into account in order to enhance the quality of visual words generated from extracted keypoints using the distance and angle information in the Bags of Visual Words (BoVW) representation. In this paper, we proposed a new computationally efficient method to model global spatial distribution of visual words by taking into consideration the spatial relationships of its visual words. In the first step, the region of interest is extracted using a scanning window with a Haar cascade detector and an AdaBoost classifier to reduce the computational region in the hypothesis generation step. Second, the regions are represented with BoVW and spatial information for classification. Experimental results show that the suggested method could reach comparable performance of the state-of-the-art approaches with less computational complexity and shorter training time. It clearly demonstrates the complementarity of the additional relative spatial information provided by our approach to improve accuracy while maintaining short retrieval time, and can obtain a better traffic sign recognition accuracy than the methods based on the traditional BoVW model.     

Electrochemical characteristics of the n+-type GaAs substrate in HCl electrolyte and the morphology of the obtained structure

The anodic etching of n⁺-type GaAs (1 0 0) substrate in HCl aqueous solution has been investigated experimentally using an in situ current–voltage J (V) and capacitance–voltage C (V) measurements. In situ current–voltage, J (V), characteristics of the n⁺-GaAs/HCl interface exhibit the presence of three potential regions, which are attributed to different reaction mechanisms between HCl and n⁺-type GaAs surface. Also, current peaks appear in the J (V) characteristics which delimit the different potential regions. According to the Mott–Schottky relation, the characteristic C^?2 (V) exhibits the presence of two linear regions separated by a shoulder at about 1.15 V. This shoulder indicates the formation of porous GaAs/HCl interface. Scanning electron microscopy (SEM) images shows that GaAs etched in HCl can produce various surface morphologies depending on the anodization current density. Reasonable assumptions on the dissolution mechanisms according to the variety of morphologies are given.     

Optical characterization of highly mismatched InP/GaAs(l11)B epitaxial heterostructures

In this work, we investigate heteroepitaxial layers of InP with various thicknesses grown by metalorganic chemical vapor deposition on (111)B surfaces of GaAs substrates. We evaluate the heteroepilayers using low temperature photoluminescence (PL) and we discuss the dependence of the PL spectrum on temperature for the thick epilayer. We determine the residual strain for the various layer thicknesses with photoluminescence excitation spectroscopy. The strain is due to different lattice constants of layer and substrate material and is relaxed by the nucleation of misfit dislocations during growth. This relaxation process depends on substrate orientation, layer thickness and growth conditions.     

In-vehicle augmented reality TSR to improve driving safety and enhance the driver’s experience

In-vehicle contextual augmented reality (AR) has the potential to provide novel visual feedbacks to drivers for an enhanced driving experience. In this paper, we propose a new AR traffic sign recognition system (AR-TSR) to improve driving safety and enhance the driver’s experience based on the Haar cascade and the Bag-of-Visual-Words approach, using spatial information to improve accuracy and an overview of studies related to the driver’s perception and the effectiveness of the AR in improving driving safety. In the first step, the region of interest (ROI) is extracted using a scanning window with a Haar cascade detector and an AdaBoost classifier to reduce the computational region in the hypothesis generation step. Second, we proposed a new computationally efficient method to model global spatial distribution of visual words by taking into consideration the spatial relationships of its visual words. Finally, a multiclass sign classifier takes the positive ROIs and assigns a 3D traffic sign for each one using a linear SVM. Experimental results show that the suggested method could reach comparable performance of the state-of-the-art approaches with less computational complexity and shorter training time, and the AR-TSR more strongly impacts the allocation of visual attention during the decision-making phase.     

Biochemical and Molecular Study of <Emphasis Type="Italic">Carpobrotus edulis</Emphasis> Bioactive Properties and Their Effects on <Emphasis Type="Italic">Dugesia sicula</Emphasis> (Turbellaria,Tricladida) Regeneration

The traditional medicinal properties of Carpobrotus edulis are well recognized, particularly in Tunisia where it is used for wound healing. Thus, in this study, biochemical and molecular properties of its leaves’ bioactive aqueous-acetone extract were investigated. The total phenolic content (TPC) of the extract was estimated to be 184 ± 5 mg/100 g of fresh matter (FM). The qualitative and quantitative polyphenolic profile was determined by ultra performance liquid chromatography with diode array detection (UPLC-DAD) and showed that chlorogenic acid was the major compound (43.7%). The extract exhibits potent antioxidant capacities with IC50 = 56.19 and 58.91 μg/ml, as accessed via the anionic DPPH and cationic ABTS radical scavenging assays, respectively. The extract has high antibacterial properties, especially against the Gram+ Staphylococcus aureus and Bacillus cereus strains. To investigate the extract effect on regeneration, the flatworm Dugesia sicula Lepori, 1948, was used as a model. The macroscopic analysis of planarian cultures in ordinary medium containing phenolic extract at non-toxic concentrations illustrated that the extract caused morphological changes. Additionally, the molecular study through the fluorescence-activated cell sorting (FACS) technique showed that C. edulis polyphenols can harm the stem cells’ development. These results emphasize the ecotoxicological impact of phenolic rejections in the environment on flatworms’ physiology.     

A new variant of cuckoo search algorithm with self adaptive parameters to solve complex RFID network planning problem

Wireless Networks - With the paradigm of the Internet of things, each object in the physical world can be remotely identified, controlled, and located through networks. Thanks to their low cost and...