Tosylmethylisocyanide (TosMIC) [3+2] cycloaddition reactions: A facile Van Leusen protocol for the synthesis of the new class of spirooxazolines,spiropyrrolines and Chromeno[3,4-c]pyrrols

The reactivity and chemo-, regio- and diastreo-selectivity of tosylmethyl isocyanides (TosMIC) are investigated in Van Leusen type [3 + 2] cycloaddition reactions with the various activate cyclic ketones and double CC bonds in the synthesis of spirooxazolines, spiropyrrolines and chromeno[3,4-c]pyrrols in good to excellent yields under catalyst-free conditions without any activation at ambient temperature.     

Electrospun Polyethylene Terephthalate/Graphene Nanocomposite as a New Solid-Phase Microextraction Fiber Coating for Enhanced Determination of Organochlorine Compounds

A new unbreakable solid-phase microextraction fiber coating based on polyethylene terephthalate/graphene nanocomposite was developed. The nanocomposite coatings were prepared by an electrospinning technique using a polyethylene terephthalate (PET) polymer solution containing the dispersed graphene on the outer surface of a stainless-steel rod. The applicability of polyethylene terephthalate/graphene nanocomposite coatings was examined by extraction of organochlorine compounds (OCs) including heptachlor epoxide, aldrin, γ-HCH, and β-HCH from aqueous samples in headspace mode. Influential parameters on extraction efficiency such as polymer concentration, the weight ratio of components, the electrospinning time, time and temperature of extraction, the salt concentration, and desorption condition were investigated. Eventually, the developed method was validated by gas chromatography micro electron capture detector (GC-µECD). At the optimum conditions, the intra-day relative standard deviations for the determination of chloro compounds in distilled water spiked at the levels of 400, 800, and 1500 ng L^??1 were 1.9–7.3% (n?=?3), the limit of detection is between 5 and 30 ng L^??1, and the calibration plots cover the 100 to 5000 ng L^??1 range. Inter-day precision values obtained for three replicates measured on different days were in the range of 2.6–9.5% at concentration levels of 400, 800, and 1500 ng L^??1. The method was applied to the analysis of (spiked) water samples and relative recoveries were found to range from 81 to 106%.     

An Energy-Aware Hybrid Approach for Wireless Sensor Networks Using Re-clustering-Based Multi-hop Routing

In recent years, cloud computing provides a spectacular platform for numerous users with persistent and alternative varying requirements. In the cloud environment, security and service availability are the two most significant factors during the data encryption process. For providing optimal service availability, it is necessary to establish a load balancing technique that is capable of balancing the request from diverse nodes present in the cloud. This paper aims in establishing a dynamic load balancing technique using the APMG approach. Here in this paper, we integrated adaptive neuro-fuzzy interference system-polynomial neural network as well as memory-based grey wolf optimization algorithm for optimal load balancing. The memory-based grey wolf optimization algorithm is employed to enhance the precision of ANFIS-PNN and to maximize the locations of the membership functions respectively. Also, two significant factors namely the turnaround time and CPU utilization involved in optimal load balancing scheme are evaluated. Finally, the performance evaluation of the proposed MG-ANFIS based dynamic load balancing approach is compared with various other load balancing approaches to determine the system performances.

     

Multiple mix zones de-correlation trajectory privacy model for road network

Preserving privacy of vehicle movement is an important challenge in road networks; as trajectory data with spatiotemporal information may reveal much individual information. One of the main threats is revealing history location of vehicle trajectories while it stops and again moves toward the destination. Generally, vehicles stop at mostly two places; the first one is traffic light (signal system)/traffic jam and second is at parking locations such as office, shopping mall, home, hospital etc. While existing works only consider social spots. To cope with this issue, we present a new multiple mix zones de-correlation privacy model in which the degree of de-correlation between parking locations and traffic light/traffic jam places. Further, we consider multiple mix zones method to replace parking locations and traffic light/traffic jam places by de-correlation mix zone region. This paper presents an improved privacy traffic monitoring system for road network applications via a proposed security scheme. Specifically, the proposed model analyzes the monitored scene and deployed mix zones parking location and traffic light/traffic jam places. Our method achieved a high privacy level and anonymity solution for trajectory model; moreover, it also balances the service quality and privacy protection. Finally, we performed experiments on real-world data and showed the effectiveness of our method in comparison to existing methods.

     

Efficient privacy-preserving group-nearest-neighbor queries with the presence of active adversaries

Location-based services (LBSs) allow users to ask location-dependent queries and receive information based on their location. A group of users can send a group-nearest-neighbor (GNN) query in order to receive a Point Of Interest (POI). This POI in turn shows a point which is the minimum distance from all members of the group. To benefit from these services, it is important to preserve the location privacy of each group user from others in the group (Intragroup location privacy) as well as from anyone outside of the group, including the LBS, (Intergroup location privacy). It may also be necessary to protect the location privacy of the resulting POI from the LBS and other possible attackers. In this paper, we propose two different privacy-preserving protocols for finding the exact answer to a GNN query among a set of returned POIs. The first protocol assumes a semi-honest model while the second one works in a malicious model. The proposed protocols are based on the Anonymous Veto network and Burmester–Desmedt key establishment protocols. The security analysis shows that the proposed protocols provide both Intragroup and Intergroup location privacy; they also protect the location privacy of the resulting POI and are resistant to collusion and multi-point aggregate distance attacks. The performed analyses indicate that they incur a constant computation cost per user and are efficient in terms of computation and communication costs.

     

Fair and stable joint beacon frequency and power control for connected vehicles

In vehicular communications, periodic one-hop broadcast of beacons allows cooperative awareness for vehicles. To avoid congestion in the shared channel used for transmission of beacons, a joint beacon frequency and power control protocol based on game theory is presented in this paper. The existence, uniqueness and stability of the Nash Equilibrium (NE) of the game is proved mathematically. An algorithm is devised to find the equilibrium point in a distributed manner and its stability and convergence has been validated using simulation. The algorithm converges to the NE from any initial frequency and power and it can provide both fairness in power and weighted fairness in frequency. The protocol has per vehicle parameters, hence, every vehicle can control its share of the bandwidth according to its dynamics or safety application requirements while the whole usage of bandwidth is controlled at a desired level.

     

Exploring Energy Efficient Architectures for RLWE Lattice-Based Cryptography

Journal of Signal Processing Systems - Quantum computers are imminent threat to secure signal processing because they can break the contemporary public-key cryptography schemes in polynomial time....     

Electrochemical behavior of electrodeposited rutin film on a multi-wall carbon nanotubes modified glassy carbon electrode. Improvement of the electrochemical reversibility and its application as a hydrazine sensor

By immobilizing rutin at the surface of a glassy carbon electrode (GCE) modified with multi-wall carbon nanotubes (MWCNT), a new modified electrode has been fabricated and its electrochemical behavior was investigated by cyclic voltammetry. Cyclic voltammograms of the resulting modified electrode show stable and a well defined redox couple with surface confined characteristics. The results show that the reversibility of rutin is significantly improved at a MWCNT modified GCE in comparison with GCE alone. The charge transfer coefficient, α, was calculated to be 0.4, and charge transfer rate constant, k_s, was 46.7 s⁻¹ in pH 8, indicating great facilitation of the electron transfer between rutin and MWCNT deposited on the electrode surface. The rutin MWCNT (RMWCNT) modified GCE showed excellent mediation of hydrazine oxidation: a decrease in the overvoltage of hydrazine electrooxidation was observed as well as a dramatic increase in the peak current compared to that seen at a rutin modified GCE (RMGCE), activated GCE or bare GCE. Hydrazine was determined amperometrically at the surface of RMWCNT modified GCE in pH 8. Under the optimized conditions the calibration curve is linear in the concentration range 2.0–190.0 μM hydrazine. The detection limit and sensitivity are 0.61 μM and 0.0656 μA μM⁻¹, respectively. Finally the kinetic parameters of the electron transfer coefficient, α, the heterogeneous rate constant of dependent to different potentials, k′(E), and the standard heterogeneous rate constant, k⁰, for oxidation of hydrazine at the RMWCNT surface were determined using various electrochemical methods. The advantages of this modified electrode for hydrazine determination are high sensitivity, excellent catalytic activity, short response time, wide linear range, and high exchange current density.     

Determination of Ibuprofen in human plasma by high-performance liquid chromatography: validation and application in pharmacokinetic study

A specific method for the simultaneous determination of S-(+)Ibuprofen and R-(-)Ibuprofen enantiomers in human plasma is described. Adopting a high-performance liquid chromatographic (HPLC) system with spectrofluorometer detector, the compounds were extracted from plasma in alcohol medium and were separated on C18 column, using a solution of acetonitrile-water-acetic acid-triethylamine as mobile phase. The limit of quantitation was 0.1 microg/mL for both compounds. The method was validated by intra-day assays at three concentration levels and was used in a kinetic study in healthy volunteers. During the study we carried out inter-day assays to confirm the feasibility of the method.     

Fabrication of a nanostructured TiO2/carbon nanotube composite electrode for voltammetric and impedimetric determination of NTO explosive in the water and soil samples

An electrochemical oxidation route was developed for sensitive and selective assay of nitrotriazolone (NTO) explosive in some environmental samples on a multi-walled carbon nanotube (MWCNTs)/TiO₂ nanocomposite paste electrode, for prevention of the analytical interference of conventional reducible energetic compounds. Detailed evaluations were made for the electrochemical behaviour of NTO on the modified electrode by adsorptive stripping voltammetry, electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques in the pH range of 2.0–10.0. Parameters such as diffusion coefficient constant of NTO were calculated, and various experimental conditions were also optimised. Under optimal conditions the calibration curve had two linear dynamic ranges of 130.0–3251.5 μg L^?1 and 6.5–26.0 mg L^?1 with a detection limit of 26.0 μg L^?1 (0.2 μmol L^?1) and precision of <3%. This electrochemical sensor was further applied to determine NTO in real soil and water samples with satisfactory results.