Abstract

Traditionally, protein structures have been analysed by the secondary structure architecture and fold arrangement. An alternative approach that has shown promise is modelling proteins as a network of non-covalent interactions between amino acid residues. The network representation of proteins provide a systems approach to topological analysis of complex three-dimensional structures irrespective of secondary structure and fold type and provide insights into structure-function relationship. We have developed a web server for network based analysis of protein structures, NAPS, that facilitates quantitative and qualitative (visual) analysis of residue–residue interactions in: single chains, protein complex, modelled protein structures and trajectories (e.g. from molecular dynamics simulations). The user can specify atom type for network construction, distance range (in Å) and minimal amino acid separation along the

Abstract

Background and objectives Information and communication and technology (ICT) has changed the entire paradigm of society. ICT facilitates people to use medical services over the Internet, thereby reducing the travel cost, hospitalization cost and time to a greater extent. Recent advancements in Telecare Medicine Information System (TMIS) facilitate users/patients to access medical services over the Internet by gaining health monitoring facilities at home. Methods Amin and Biswas recently proposed a RSA-based user authentication and session key agreement protocol usable for TMIS, which is an improvement over Giri et al.'s RSA-based user authentication scheme for TMIS. In this paper, we show that though Amin–Biswas's scheme considerably improves the security drawbacks of Giri et al.'s scheme, their scheme has security weaknesses as it suffers from attacks such as privileged insider attack, user impersonation attack, replay attack and also offline password guessing attack. A new RSA-based user authentication scheme for TMIS is proposed, which overcomes the security pitfalls of Amin–Biswas's scheme and also preserves user anonymity property. Results The careful formal security analysis using the two widely accepted Burrows–Abadi–Needham (BAN) logic and the random oracle models is done. Moreover, the informal security analysis of the scheme is also done. These security analyses show the robustness of our new scheme against the various known attacks as well as attacks found in Amin–Biswas's scheme. The simulation of the proposed scheme using the widely accepted Automated Validation of Internet Security Protocols and Applications (AVISPA) tool is also done. Conclusions We present a new user authentication and session key agreement scheme for TMIS, which fixes the mentioned security pitfalls found in Amin–Biswas's scheme, and we also show that the proposed scheme provides better security than other existing schemes through the rigorous security analysis and verification tool. Furthermore, we present the formal security verification of our scheme using the widely accepted AVISPA tool. High security and extra functionality features allow our proposed scheme to be applicable for telecare medicine information systems which is used for e-health care medical applications.

Abstract

Mobile Healthcare (mHealth) continues to improve because of significant improvements and the decreasing costs of Information Communication Technologies (ICTs). mHealth is a medical and public health practice, which is supported by mobile devices (for example, smartphones) and, patient monitoring devices (for example, various types of wearable sensors, etc.). An mHealth system enables healthcare experts and professionals to have ubiquitous access to a patient’s health data along with providing any ongoing medical treatment at any time, any place, and from any device. It also helps the patient requiring continuous medical monitoring to stay in touch with the appropriate medical staff and healthcare experts remotely. Thus, mHealth has become a major driving force in improving the health of citizens today. First, we discuss the security requirements, issues and threats to the mHealth system. We then present a taxonomy of recently proposed security protocols for mHealth system based on features supported and possible attacks, computation cost and communication cost. Our detailed taxonomy demonstrates the strength and weaknesses of recently proposed security protocols for the mHealth system. Finally, we identify some of the challenges in the area of security protocols for mHealth systems that still need to be addressed in the future to enable cost-effective, secure and robust mHealth systems.

Abstract

In [1] the authorship was originally shown as “Ashok Kumar Das, Dheerendra Mishra and Sourav Mukhopadhyay”. This has now been corrected to “Dheerendra Mishra, Ashok Kumar Das and Sourav Mukhopadhyay”. We apologize for any inconvenience caused … 1. Mishra D, Das AK, Mukhopadhyay S. An anonymous and secure biometric-based enterprise digital rights management system for mobile environment. Security and Communica- tions Networks2015;8:3383–3404 . doi:10.1002/sec.1266." … SECURITY AND COMMUNICATION NETWORKS Security Comm. Networks 2016; 9:3762 … Published online 18 August 2016 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/sec.1604

Abstract

Wireless sensor networks (WSNs) have several applications ranging from the civilian to military applications. WSNs are prone to various hole attacks, such as sinkhole, wormhole, blackhole, and greyhole. Among these hole attacks, the sinkhole attack is the malignant one. A sinkhole attack allows a malicious node, called the sinkhole node, advertises a best possible path to the base station (BS). This misguides its neighbors to utilize that path more frequently. The sinkhole node has the opportunity to tamper with the data, and it also performs the modifications in messages or it drops messages or it produces unnecessary delay before forwarding them to the BS. On the basis of these malicious acts that are performed by a sinkhole attacker node, we consider three types of malicious nodes in a WSN: sinkhole message modification node (SMD), sinkhole message dropping node (SDP), and sinkhole message delay node (SDL). None of the existing techniques in the literature is capable to handle all three types of nodes at a time. This paper presents a new detection scheme for the detection of different types of sinkhole nodes for a hierarchical wireless sensor network (HWSN). To the best of our knowledge, this is the first attempt to design such a detection scheme in HWSNs which can detect SMD, SDP, and SDL nodes. In our approach, the entire HWSN is divided into several disjoint clusters, and each cluster has a powerful high-end sensor node (called a cluster head), which is responsible for the detection of different sinkhole attacker nodes if present in that cluster. We simulate our scheme using the widely-accepted NS2 simulator for measurement of various network parameters. The proposed scheme achieves around 95% detection rate and 1.25% false positive rate. These factors are significantly better than the previous related schemes. Furthermore, the computation and communication efficiency is achieved in our scheme. As a result, our scheme seems suitable for the sensitive critical applications, such as military applications.

Abstract

Mangrove, the intertidal halophytic vegetation, are one of the most significant and diverse ecosystem in the world. They protect the coast from sea erosion and other natural disasters like tsunami and cyclone. In view of their increased destruction and degradation in the current scenario, mapping of this vegetation is at priority. Globally researchers mapped mangrove vegetation using visual interpretation method or digital classification approaches or a combination of both (hybrid) approaches using varied spatial and spectral data sets. In the recent past techniques have been developed to extract these coastal vegetation automatically using varied algorithms. In the current study we tried to delineate mangrove vegetation using LISS III and Landsat 8 data sets for selected locations of Andaman and Nicobar islands. Towards this we made an attempt to use segmentation method, that characterize the mangrove vegetation based on their tone and the texture and the pixel based classification method, where the mangroves are identified based on their pixel values. The results obtained from the both approaches are validated using maps available for the region selected and obtained better accuracy with respect to their delineation. The main focus of this paper is simplicity of the methods and the availability of the data on which these methods are applied as these data (Landsat) are readily available for many regions. Our methods are very flexible and can be applied on any region.

Abstract

Studies of metal nanoclusters can provide valuable information on how various properties evolve in the nanoscale materials. Previously often mixed-sized products have been separated in order to study their size-related properties. We present here a one-pot aqueous synthesis protocol that allows direct observations of the evolutions of size-dependent optical and electrochemical properties of the gold nanoclusters while the clusters grow from a few-atom, ultra-small size to the plasmonic nanoparticle stage. Our selection of a mixed ligand system comprising of methionine and CTAB for the aqueous synthesis of gold nanoclusters by the chemical reduction of gold ions led to the slow growth of the nanoclusters making direct observations of the cluster growth and concomitant evolution of properties possible. UV-visible spectrophotometric and dynamic light scattering studies demonstrated the size-dependent transition from the molecule-like, non-plasmonic to plasmonic properties in the evolving nanoclusters. Differential pulse voltammetry studies demonstrated how the electrochemical properties changed from the molecule-like redox behavior to a quantized double-layer charging type with the growth of the nanocluster with time. Thermogravimetric analysis, MALDI-TOF mass spectrometry, etc. were employed to further characterize the nanocluster systems. This report will inspire further studies in understanding the evolution of the size-dependent

Abstract

Gold clusters are currently regarded as new-generation catalysts owing to their exceptional efficiency in accelerating several classes of reactions. Density functional theory (DFT) is the method of choice for the investigation of energy pathways of reactions assisted by metal nanoparticles due to their computational efficiency. However, the reliability of such theoretical studies depends to a large extent on the choice of the DFT functional used. In the present work, the performance of a series of DFT-based functionals to accurately model the prototypical CO oxidation reaction catalyzed by a cluster has been examined by comparing the results with those obtained from high-level ab initio CCSD(T) method. This comparison study has been carried along the two possible pathways [Eley–Rideal (ER) and the Langmuir–Hinshelwood (LH)]. No significant differences among the DFT functionals were observed in …

Abstract

Multidrug resistance in Mycobacterium tuberculosis (M. Tb) and its coexistence with HIV are the biggest therapeutic challenges in anti-M. Tb drug discovery. The current study reports a Virtual Screening (VS) strategy to identify potential inhibitors of Mycobacterial cyclopropane synthase (CmaA1), an important M. Tb target considering the above challenges. Five ligand-based pharmacophore models were generated from 40 different conformations of the cofactors of CmaA1 taken from molecular dynamics (MD) simulations trajectories of CmaA1. The screening abilities of these models were validated by screening 23 inhibitors and 1398 non-inhibitors of CmaA1. A VS protocol was designed with four levels of screening i.e., ligand-based pharmacophore screening, structure-based pharmacophore screening, docking and absorption, distribution, metabolism, excretion and the toxicity (ADMET) filters. In an …

Abstract

Bimetallic nanoparticles (NPs) have been shown to exhibit certain advantages over pure NPs in catalysis due to a synergistic effect. It is common to disperse NPs in a polymer matrix such as polyvinylpyrrolidone (PVP) to prevent flocculation, which imparts considerable electronic effects on the NPs. In the present study, the interactions between aqueous solutions of N-ethylpyrrolidone (EP, system chosen to model the monomeric form of PVP) and Au/Pd bimetallic NPs, which are relevant in catalysis, have been investigated using molecular dynamics simulations and density functional theory (DFT) method. The adequacy of the force fields used was assessed based on their ability to reproduce the structures and adsorption energies obtained using DFT calculations. The interactions of NPs with the environment were studied at various concentrations of aqueous solutions of EP to examine the strength of NP–EP and NP …