4,306 research outputs found

    Improving Air Interface User Privacy in Mobile Telephony

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    Although the security properties of 3G and 4G mobile networks have significantly improved by comparison with 2G (GSM), significant shortcomings remain with respect to user privacy. A number of possible modifications to 2G, 3G and 4G protocols have been proposed designed to provide greater user privacy; however, they all require significant modifications to existing deployed infrastructures, which are almost certainly impractical to achieve in practice. In this article we propose an approach which does not require any changes to the existing deployed network infrastructures or mobile devices, but offers improved user identity protection over the air interface. The proposed scheme makes use of multiple IMSIs for an individual USIM to offer a degree of pseudonymity for a user. The only changes required are to the operation of the authentication centre in the home network and to the USIM, and the scheme could be deployed immediately since it is completely transparent to the existing mobile telephony infrastructure. We present two different approaches to the use and management of multiple IMSIs

    Observations on antifertility and abortifacient herbal drugs

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    This communication presents first hand information gathered on 36 medicinal plants belonging to 23 families traditionally used by the tribal and rural women of northern areas of North West Frontier Province (NWFP), Pakistan for birth control. Study provides information on local names, mode of administration and dosages as `practiced by rural and tribal women. Most effective plant species to induce abortion include: Artemisia maritime L., Boerhavaia diffusa Auct. Plur., Buddleja asiatica Lour, Chrysanthemum parthenium (L.) Bernh, Justacia adhatod L., Ricinus communis L., Zingiber officinale Roscol., Daucus crota L., Momordica charantia L., Plumbago zeylanica L., Sapindus mukorossi Gaertn., Plantago ovata Forssk, Tanacetum vulgare and Arctium lappa L. The most widely used contraceptives are: Amaranthus viridis L., Achyranthes aspera L., Ricinus communis L., Mentha arvensis L., Nepeta cataria L., Cuscuta reflexa Roxb., Curcuma longa L., Foeniculum vulgare Miller., Butea monosperma (Lam.) O. Kze., Albizia lebbeck (L.) Bth., Ficus religosa L. and Mentha longifolia (L.) Huds. The tribalpopulation of the region primarily depends upon these plants for family planning. They use herbal drugs to induce abortion and as contraceptives. Further studies on chemical and pharmacologicalactions are suggested to validate the claims

    Formulation and Evaluation of Tramadol HCl Matrix Tablets Using Carbopol 974P and 934 as Rate-Controlling Agents

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    Purpose: To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 974P and 934 polymers as rate-controlling agents.Methods: The tablets were prepared by direct compression method using various drug to polymer (D:P) ratios. Co-excipients, including carboxymethylcellulose, starch and/or hydroxypropyl methylcellulosewere also used to modulate the formulations. Various physical tests and in vitro dissolution studies were carried out on the formulations. The dissolution data were subjected to various release modelsResults: As the concentration of the polymer (rate-controlling agent) increased, dissolution rate decreased, For the formulation containing Carbopol 974P at D:P ratio of 10:7, drug release decreased to 83 % compared with the release rate of 99 % for the formulation with D:P ratio of 10:3. Kinetic analysis indicates that drug release mechanism was anomalous non-Fickian diffusion.Conclusion: Both Carbopol 974P and 934 can be used as rate-controlling agents in the formulation of tramadol HCl CR tablets. Appropriate selection of drug/polymer ratio can be applied effectively to modulate the dissolution rate of the drug.Keywords: Tramadol, Carbopol, Carboxymethylcellulose (CMC), Hydroxypropyl methylcellulose, Controlled releas

    Enhanced regeneration in explants of tomato (Lycopersicon esculentum L.) with the treatment of coconut water

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    A standardized protocol was developed to enhance the in vitro regeneration efficiency of five varieties of tomato from hypocotyls and leaf disc with the involvement of coconut water. Different concentrations of IAA and kinetin were used alone and in combination with 12% of coconut water.Significant differences for regeneration, time taken to regenerate and number of leaf primordial were observed for different treatments, type of explant, use of coconut water and also among varieties. Higher regeneration was obtained in Avinash followed by Roma and Rio Grande. Maximum regeneration 95.75% was obtained with 0.5 mgL-1 of IAA, 1.5 mgL-1 Kinetin along with 12% coconut water in Avinash and hypocotyl was proved to be better for regeneration than leaf discs. The inclusionof coconut water in the media significantly reduced the number of days taken for callus induction leading to regeneration, as compared to media without coconut water. Significant increase in number of shoot primordial was observed in hypocotyls as well as in leaf disc derived calli with the addition of coconut water. Plants obtained were transferred to the glass house in small pots of compost and higher frequency of survival was observed from plantlets obtained with the addition of coconut water

    Intercultural New Media Studies: The Next Frontier in intercultural Communication

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    New media (ICT\u27s) are transforming communication across cultures. Despite this revolution in cross cultural contact, communication researchers have largely ignored the impact of new media on intercultural communication. This groundbreaking article defines the parameters of a new field of inquiry called Intercultural New Media Studies (INMS), which explores the intersection between ICT\u27s and intercultural communication. Composed of two research areas—(1) new media and intercultural communication theory and (2) culture and new media—INMS investigates new digital theories of intercultural contact as well as refines and expands twentieth-century intercultural communication theories, examining their salience in a digital world. INMS promises to increase our understanding of intercultural communication in a new media age and is the next frontier in intercultural communication

    Real-time Processor-in-Loop investigation of a modified non-linear state observer using sliding modes for speed sensorless induction motor drive in electric vehicles

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    Tracking performance and stability play a major role in observer design for speed estimation purpose in motor drives used in vehicles. It is all the more prevalent at lower speed ranges. There was a need to have a tradeoff between these parameters ensuring the speed bandwidth remains as wide as possible. This work demonstrates an improved static and dynamic performance of a sliding mode state observer used for speed sensorless 3 phase induction motor drive employed in electric vehicles (EVs). The estimated torque is treated as a model disturbance and integrated into the state observer while the error is constrained in the sliding hyperplane. Two state observers with different disturbance handling mechanisms have been designed. Depending on, how they reject disturbances, based on their structure, their performance is studied and analyzed with respect to speed bandwidth, tracking and disturbance handling capability. The proposed observer with superior disturbance handling capabilities is able to provide a wider speed range, which is a main issue in EV. Here, a new dimension of model based design strategy is employed namely the Processor-in-Loop. The concept is validated in a real-time model based design test bench powered by RT-lab. The plant and the controller are built in a Simulink environment and made compatible with real-time blocksets and the system is executed in real-time targets OP4500/OP5600 (Opal-RT). Additionally, the Processor-in-Loop hardware verification is performed by using two adapters, which are used to loop-back analog and digital input and outputs. It is done to include a real-world signal routing between the plant and the controller thereby, ensuring a real-time interaction between the plant and the controller. Results validated portray better disturbance handling, steady state and a dynamic tracking profile, higher speed bandwidth and lesser torque pulsations compared to the conventional observer

    Earliest-deadline-based scheduling to reduce urban traffic congestion

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    One of the major problems, caused by traffic congestion, owes its existence to the unwanted delay experienced by the priority vehicles. The evaluation of two scheduling algorithms as adaptive traffic control algorithms has been proposed here to reduce this unwanted delay. One of these algorithms is the earliest deadline first (EDF) algorithm, whereas the other is the fixed priority (FP) algorithm. The performance of both algorithms as adaptive traffic light control algorithms is evaluated for isolated traffic intersections. A comparative study is performed here, where the performance of these algorithms is compared against a fixed static traffic light controller. Moreover, their performance is also compared against each other. Conclusive results from the simulation of the algorithms reveal that the number of stops, average delay, and mean trip time of the priority vehicles is significantly reduced by the implementation of these algorithms. Furthermore, it has been shown that the overall performance of EDF is much better than FP in terms of improvement of different performance measures for congestion reduction of priority vehicles. © 2014 IEEE

    Evaluations of the effect of sodium metabisulfite on the stability and dissolution rates of various model drugs from the extended release polyethylene oxide matrices

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    Purpose: This study examines the effect of sodium metabisulfite (SMB) as an antioxidant on the stability and release of various model drugs namely propranolol HCl, theophylline and zonisamide from the polyethylene oxide (PEO) tablets. The antioxidant was used to minimise degradation and instability of the manufactured tablets when stored at 40°C (55±5 % RH) over 8 weeks. Method: Multiple batches of tablets weighing 240 mg (50% w/w) with a ratio of 1:1 drug: polymer and 1% (w/w) sodium metabisulfite containing different model drugs and various molecular weights of PEO 750 and 303 were produced. Results: The results indicated that the use of sodium metabisulfite marginally assisted in reducing drug release and degradation via oxidation in propranolol HCl tablets containing both PEO 750 and 303. In the case of poorly and semi-soluble drugs (zonisamide and theophylline) the formulations with both PEO showed entirely superimposable phenomenon and different release profiles compared to control samples (matrices without SMB). DSC study demonstrated the modifications of the polymer due to degradation and observed the effect of SMB on the thermal degradation of the PEO matrices. Conclusion: The use of antioxidant has assisted in retaining the stability of the manufactured tablets with different model drugs especially those with the highly soluble drug that are susceptible to rapid degradation. This has been reflected by an extended release profile of various drugs used at various stages of the storage time up to 8 weeks

    Platelet-rich plasma induces post-natal maturation of immature articular cartilage and correlates with LOXL1 activation

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    Platelet-­rich plasma (PRP) is used to stimulate the repair of acute and chronic cartilage damage even though there is no definitive evidence of how this is achieved. Chondrocytes in injured and diseased situations frequently re­ express phenotypic biomarkers of immature cartilage so tissue maturation is a potential pathway for restoration of normal structure and function. We used an in vitro model of growth factor­induced maturation to perform a comparative study in order to determine whether PRP can also induce this specific form of remodeling that is characterised by increased cellular proliferation and tissue stiffness. Gene expression patterns specific for maturation were mimicked in PRP treated cartilage, with chondromodulin, collagen types II/X downregulated, deiodinase II and netrin­1 upregulated. PRP increased cartilage surface cell density 1.5­fold (P < 0.05), confirmed by bromodeoxyuridine incorporation and proportionate increases in proliferating cell nuclear antigen gene expression. Atomic force microscopy analysis of PRP and growth factor treated cartilage gave a 5­fold increase in stiffness correlating with a 10­fold upregulation of lysyl oxidase like­1 gene expression (P < 0.001). These data show PRP induces key aspects of post­natal maturation in immature cartilage and provides the basis to evaluate a new biological rationale for its activity when used clinically to initiate joint repair
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