Group Key Rekeying Technique with Secure Data Encryption in MANETs

A Mobile Ad hoc Network (MANET) is a collection of autonomous nodes or mobile devices that can arrange themselves in various ways and operate without strict network administration. Ensuring security in mobile ad hoc network is a challenging issue and most of the applications in mobile ad hoc networks involve group-oriented communication. In Mobile ad-hoc network, each node treated as a terminal and also acts as an intermediate router. In this scenario, multi-hop occurs for communication in mobile ad hoc network. There may be a possibility of threats and malicious nodes in between source and destination. Providing the security in MANET is entirely different from the traditional wired network. In the present scenario, various applications of the mobile ad hoc network have been proposed and issues are solved by using the cryptographic techniques. Mostly cryptographic techniques are used to provide the security to MANETs. Cryptographic techniques will not be efficient security mechanism if the key management is weak. The purpose of key management is to provide secure procedures for handling keys in the cryptographic technique. The responsibilities of key management include key generation, key distribution, and key maintenance. Several key management schemes have been introduced for MANETs. The Group key management scheme is an efficient method for key management in MANET. In group key management scheme, rekeying is used whenever a new node joins or existing node leaves from the group. In this paper, we propose a periodic rekeying method (PRK) and analyze the performance of LKH rekeying techniques in a group key management schemes. The symmetric encryption techniques are analyzed with different parameters, such as Throughput and Energy consumption. Security and performance of rekeying protocols are analyzed through detailed study and simulation

GPRKEY - A NOVEL GROUP KEY REKEYING TECHNIQUE FOR MANET

A Mobile Ad hoc Network (MANET) is a collection of autonomous nodes or mobile devices that can arrange themselves in various ways and work without strict network administration. Ensuring security in mobile ad hoc networks is a challenging issue and most of the applications in mobile ad hoc networks involve group oriented communication. Mostly cryptographic techniques are used to provide the security to MANETs. Cryptographic techniques will not be efficient security mechanism if the key management is weak. The issue of packet loss in MANET that is caused due to multi casting and backward and forward secrecy results in mobility. Hence, we investigate on this issue and propose a method to overcome this scenario. On analysing the situation we find that frequent rekeying leads to huge message overhead and hence increases energy utilization. With the existing key management techniques it causes frequent disconnections and mobility issues. Therefore, an efficient multi casting group key management will help to overcome the above problems. In this paper we propose a novel group key rekeying technique named GPRKEY (Group key with Periodic ReKEYing) deal with scalability issue of rekeying and also analyze the performance of the newly proposed key management method using key trees. In this approach we use the periodic rekeying to enhance the scalability and avoid out of sync problems. We use sub trees and combine them using the merging algorithm and periodic re-keying algorithm. The GPRKEY is evaluated through NS-2 simulation and compared with existing key management techniques OFT (One-way Function Tree) and LKH (Logical Key Hierarchy). The security and performance of rekeying protocols are analyzed through detailed study and simulation

Submerged membrane filtration adsorption hybrid system for the removal of organic micropollutants from a water reclamation plant reverse osmosis concentrate

© 2016 Elsevier B.V. Reverse osmosis (RO) is a widespread water treatment process utilised in water reuse applications. However, the improper discharge of RO concentrate (ROC) containing organic micropollutants such as pharmaceuticals into the environment may cause potential health risks to non-target species and particularly those in aquatic environments. A study was conducted using a submerged membrane-filtration/granular activated carbon (GAC) adsorption hybrid system to remove organic micropollutants from a water treatment plant ROC by initially adding 10 g GAC /L of membrane reactor volume with 10% daily GAC replacement. The percentage of dissolved organic carbon removal varied from 60% to 80% over an operation lasting 10 days. Removal of organic micropollutants was almost complete for virtually all compounds. Of the 19 micropollutants tested, only two remained (the less hydrophobic DEET 27 ng/L and the hydrophilic sulfamethoxazole 35 ng/L) below 80% removal on day 1, while five of the most hydrophobic micropollutants were detectable in very small concentrations ( 89%–> 99% being removed. High percentages of micropollutants were removed probably because of their high hydrophobicity or they had positive or neutral charges and therefore they were electrostatically adsorbed to the negatively charged GAC

Case Series of Triathletes with Takotsubo Cardiomyopathy Presenting with Swimming-Induced Pulmonary Edema

OBJECTIVES: To report three cases of triathletes who presented with swimming-induced pulmonary edema (SIPE) following water immersion. They were subsequently diagnosed with Takotsubo cardiomyopathy (TCM). DESIGN: Retrospective case series. METHOD: All cases were recreational athletes competing in mass participation triathlons between June 2018 and 2019. They were initially managed by the event medical team and subsequently at the local tertiary level hospital. Written consent was gained from all the subjects. RESULTS: The three triathletes were aged between 50 and 60 years, two were females, and all presented with acute dyspnoea on exiting the water. Two also presented with chest pain and haemoptysis. A diagnosis of SIPE was suspected by the medical event team on initial presentation of low oxygen saturations and clinical signs of pulmonary oedema. All were transferred to the local emergency department and had signs of pulmonary oedema on chest radiographs. Further investigations led to a diagnosis of TCM with findings of T wave inversion in anterolateral electrocardiogram leads and apical hypokinesia on transthoracic echocardiogram and unobstructed coronary arteries. CONCLUSIONS: This case series presents triathletes diagnosed with SIPE and TCM following the open water swim phase. It is unclear whether the myocardial dysfunction contributed to causation of SIPE or was the result of SIPE. Mass participation race organizers must be prepared that both SIPE and TCM can present in this population. Those presenting with an episode of SIPE require prompt evaluation of their cardiac and pulmonary physiology. Further research is required to ascertain the exact nature of the relationship between TCM and SIPE

A superior drug carrier – aponeocarzinostatin in partially unfolded state fully protects the labile antitumor enediyne

<p>Abstract</p> <p>Background</p> <p>Neocarzinostatin is a potent antitumor drug consisting of an enediyne chromophore and a protein carrier.</p> <p>Methods</p> <p>We characterized an intermediate in the equilibrium unfolding pathway of aponeocarzinostatin, using a variety of biophysical techniques including 1-anilino-8-napthalene sulfonate binding studies, size-exclusion fast protein liquid chromatography, intrinsic tryptophan fluorescence, circular dichroism, and ¹H-¹⁵N heteronuclear single quantum coherence spectroscopy.</p> <p>Results</p> <p>The partially unfolded protein is in molten globule-like state, in which ~60% and ~20% tertiary and secondary structure is disrupted respectively. Despite lacking a fully coordinated tertiary structure for assembling a functional binding cleft, the protein in molten globule-like state is still able to fully protect the labile chromophore. Titration of chromophore leads the partially denatured apoprotein to fold into its native state.</p> <p>Conclusion</p> <p>These findings bring insight into conserving mechanism of neocarzinostatin under harsh environment, where even the partially denatured apoprotein exhibits protective effect, confirming the superiority of the drug carrier.</p

Does the Spine Surgeon’s Experience Affect Fracture Classification, Assessment of Stability, and Treatment Plan in Thoracolumbar Injuries?

Study Design: Prospective survey-based study. Objectives: The AO Spine thoracolumbar injury classification has been shown to have good reproducibility among clinicians. However, the influence of spine surgeons’ clinical experience on fracture classification, stability assessment, and decision on management based on this classification has not been studied. Furthermore, the usefulness of varying imaging modalities including radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) in the decision process was also studied. Methods: Forty-one spine surgeons from different regions, acquainted with the AOSpine classification system, were provided with 30 thoracolumbar fractures in a 3-step assessment: first radiographs, followed by CT and MRI. Surgeons classified the fracture, evaluated stability, chose management, and identified reasons for any changes. The surgeons were divided into 2 groups based on years of clinical experience as \u3c10 years (n = 12) and \u3e10 years (n = 29). Results: There were no significant differences between the 2 groups in correctly classifying A1, B2, and C type fractures. Surgeons with less experience hadmore correct diagnosis in classifyingA3 (47.2% vs 38.5%in step 1, 73.6% vs 60.3% in step 2 and 77.8% vs 65.5% in step 3), A4 (16.7% vs 24.1% in step 1, 72.9% vs 57.8% in step 2 and 70.8% vs 56.0%in step3) and B1 injuries (31.9% vs 20.7% in step 1, 41.7% vs 36.8% in step 2 and 38.9% vs 33.9% in step 3). In the assessment of fracture stability and decision on treatment, the less and more experienced surgeons performed equally. The selection of a particular treatment plan varied in all subtypes except in A1 and C type injuries. Conclusion: Surgeons’ experience did not significantly affect overall fracture classification, evaluating stability and planning the treatment. Surgeons with less experience had a higher percentage of correct classification in A3 and A4 injuries. Despite variations between them in classification, the assessment of overall stability and management decisions were similar between the 2 groups. © The Author(s) 2017

Impact of Splenic Artery Embolization on the Success Rate of Nonoperative Management for Blunt Splenic Injury

Introduction Nonoperative management (NOM) has become the treatment of choice for hemodynamically stable patients with blunt splenic injury. Results of outcome after NOM are predominantly based on large-volume studies from level 1 trauma centers in the United States. This study was designed to assess the results of NOM in a relatively low-volume Dutch level 1 trauma center. Methods An analysis of a prospective trauma registry was performed for a 6-year period before (period 1) and after the introduction and implementation of splenic artery embolization (SAE) (period 2). Primary outcome was the failure rate of initial treatment. Results A total of 151 patients were reviewed. An increased use of SAE and a reduction of splenic operations during the second period was observed. Compared with period 1, the failure rate after observation in period 2 decreased from 25% to 10%. The failure rate after SAE in period 2 was 18%. The splenic salvage rate (SSR) after observation increased from 79% in the first period to 100% in the second period. During the second period, all patients with failure after observation were successfully treated with SAE. The SSR after SAE in periods 1 and 2 was respectively 100% and 86%. Conclusions SAE of patients with blunt splenic injuries is associated with a reduction in splenic operations. The failure and splenic salvage rates in this current study were comparable with the results from large-volume studies of level 1 trauma centers. Nonoperative management also is feasible in a relatively low-volume level 1 trauma center outside the United State

Diffusion Tensor Imaging and Tractography in Brown-Sequard Syndrome

This report illustrates the utility of DTI and DTT in delineating regions of cord injury in two patients with traumatic Brown-Sequard syndrome. Our results indicate that DTI provides clinically relevant information that supplements conventional MR imaging for patients with acute SCI