An analysis on decentralized adaptive MAC protocols for Cognitive Radio networks

The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum and inefficiency in its utilization has been smartly addressed by the Cognitive Radio (CR) Technology which is an opportunistic network that senses the environment, observes the network changes, and then using knowledge gained from the prior interaction with the network, makes intelligent decisions by dynamically adapting their transmission characteristics. In this paper some of the decentralized adaptive MAC protocols for CR networks have been critically analyzed and a novel adaptive MAC protocol for CR networks, DNG-MAC which is decentralized and non-global in nature, has been proposed. The results show the DNG-MAC out performs other CR MAC protocols in terms of time and energy efficiency

A nanocommunication system for endocrine diseases

Nanotechnology is a newand very promising area of research which will allow several new applications to be created in different fields, such as, biological, medical, environmental, military, agricultural, industrial and consumer goods. This paper focuses specifically on nanocommunications, which will allow interconnected devices, at the nano-scale, to achieve collaborative tasks, greatly changing the paradigm in the fields described. Molecular communication is a new communication paradigm which allows nanomachines to exchange information using molecules as carrier. This is the most promising nanocommunication method within nanonetworks, since it can use bio-inspired techniques, inherit from studied biological systems, which makes the connection of biologic and man-made systems a easier process. At this point, the biggest challenges in these type of nanocommunication are to establish feasible and reliable techniques that will allow information to be encoded, and mechanisms that ensure a molecular communication between different nodes. This paper focus on creating concepts and techniques to tackle these challenges, and establishing new foundations on which future work can be developed. The created concepts and techniques are then applied in an envisioned medical application, which is based on a molecular nanonetwork deployed inside the Human body. The goal of this medical application is to automatously monitor endocrine diseases using the benefits of nanonetworks, which in turn connects with the internet, thus creating a Internet of NanoThings system. The concepts and techniques developed are evaluated by performing several simulations and comparing with other researches, and the results and discussions are presented on the later sections of this paper

Underground Environment Aware MIMO Design Using Transmit and Receive Beamforming in Internet of Underground Things

In underground (UG) multiple-input and multiple-output (MIMO), the transmit beamforming is used to focus energy in the desired direction. There are three different paths in the underground soil medium through which the waves propagates to reach at the receiver. When the UG receiver receives a desired data stream only from the desired path, then the UG MIMO channel becomes three path (lateral, direct, and reflected) interference channel. Accordingly, the capacity region of the UG MIMO three path interference channel and degrees of freedom (multiplexing gain of this MIMO channel requires careful modeling). Therefore, expressions are required derived the degrees of freedom of the UG MIMO interference channel. The underground receiver needs to perfectly cancel the interference from the three different components of the EM-waves propagating in the soil medium. This concept is based upon reducing the interference the undesired components to minimum at UG receiver using the receive beamforming. In this paper, underground environment aware MIMO using transmit and receive beamforming has been developed. The optimal transmit beamforming and receive combin- ing vectors under minimal inter-component interference constraint are derived. It is shown that UG MIMO performs best when all three component of the wireless UG channel are leveraged for beamforming. The environment aware UG MIMO technique leads to three-fold performance improvements and paves the wave for design and development of next generation sensor-guided irrigation systems in the field of digital agriculture

A survey on MAC protocols for complex self-organizing cognitive radio networks

Complex self-organizing cognitive radio (CR) networks serve as a framework for accessing the spectrum allocation dynamically where the vacant channels can be used by CR nodes opportunistically. CR devices must be capable of exploiting spectrum opportunities and exchanging control information over a control channel. Moreover, CR nodes should intelligently coordinate their access between different cognitive radios to avoid collisions on the available spectrum channels and to vacate the channel for the licensed user in timely manner. Since inception of CR technology, several MAC protocols have been designed and developed. This paper surveys the state of the art on tools, technologies and taxonomy of complex self-organizing CR networks. A detailed analysis on CR MAC protocols form part of this paper. We group existing approaches for development of CR MAC protocols and classify them into different categories and provide performance analysis and comparison of different protocols. With our categorization, an easy and concise view of underlying models for development of a CR MAC protocol is provided

Multi-Channel Distributed Coordinated Function over Single Radio in Wireless Sensor Networks

Multi-channel assignments are becoming the solution of choice to improve performance in single radio for wireless networks. Multi-channel allows wireless networks to assign different channels to different nodes in real-time transmission. In this paper, we propose a new approach, Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks (WSNs) over 802.11 networks. We presented simulation experiments in order to investigate the characteristics of multi-channel communication in wireless sensor networks using an NS2 platform. Nodes only use a single radio and perform channel switching only after specified threshold is reached. Single radio can only work on one channel at any given time. All nodes initiate constant bit rate streams towards the receiving nodes. In this work, we studied the impact of non-overlapping channels in the 2.4 frequency band on: constant bit rate (CBR) streams, node density, source nodes sending data directly to sink and signal strength by varying distances between the sensor nodes and operating frequencies of the radios with different data rates. We showed that multi-channel enhancement using our proposed algorithm provides significant improvement in terms of throughput, packet delivery ratio and delay. This technique can be considered for WSNs future use in 802.11 networks especially when the IEEE 802.11n becomes popular thereby may prevent the 802.15.4 network from operating effectively in the 2.4 GHz frequency band

Interactive models of communication at the nanoscale using nanoparticles that talk to one another

[EN] 'Communication' between abiotic nanoscale chemical systems is an almost-unexplored field with enormous potential. Here we show the design and preparation of a chemical communication system based on enzyme-powered Janus nanoparticles, which mimics an interactive model of communication. Cargo delivery from one nanoparticle is governed by the biunivocal communication with another nanoparticle, which involves two enzymatic processes and the interchange of chemical messengers. The conceptual idea of establishing communication between nanodevices opens the opportunity to develop complex nanoscale systems capable of sharing information and cooperating.A. L.-L. is grateful to 'La Caixa' Banking Foundation for his PhD fellowship. We wish to thank the Spanish Government (MINECO Projects MAT2015-64139-C4-1, CTQ2014-58989-P and CTQ2015-71936-REDT and AGL2015-70235-C2-2-R) and the Generalitat Valenciana (Project PROMETEOII/2014/047) for support. The Comunidad de Madrid (S2013/MIT-3029, Programme NANOAVANSENS) is also gratefully acknowledged.Llopis-Lorente, A.; Díez, P.; Sánchez, A.; Marcos Martínez, MD.; Sancenón Galarza, F.; Martínez-Ruiz, P.; Villalonga, R.... (2017). Interactive models of communication at the nanoscale using nanoparticles that talk to one another. Nature Communications. 8:1-7. https://doi.org/10.1038/ncomms15511S178Tseng, R., Huang, J., Ouyang, J., Kaner, R. & Yang, Y. Polyaniline nanofiber/gold nanoparticle nonvolatile memory. Nano Lett. 5, 1077–1080 (2005).Liu, R. & Sen, A. Autonomous nanomotor based on copper-platinum segmented nanobattery. J. Am. Chem. Soc. 133, 20064–20067 (2011).Valov, I. et al. Nanobatteries in redox-based resistive switches require extension of memristor theory. Nat. Commun. 4, 1771 (2013).Tarn, D. et al. Mesoporous silica nanoparticle nanocarriers: biofunctionality and biocompatibility. Acc. Chem. Res. 46, 792–801 (2013).Kline, T. & Paxton, W. Catalytic nanomotors: remote-controlled autonomous movement of striped metallic nanorods. Angew. Chem. Int. Ed. 117, 754–756 (2005).Akyildiz, I. F., Brunetti, F. & Blázquez, C. Nanonetworks: a new communication paradigm. Comput. Netw. 52, 2260–2279 (2008).Suda, T., Moore, M., Nakano, T., Egashira, R. & Enomoto, A. Exploratory research on molecular communication between nanomachines. Nat. Comput. 25, 1–30 (2005).Malak, D. & Akan, O. B. Molecular communication nanonetworks inside human body. Nano Commun. Netw. 3, 19–35 (2012).Akyildiz, I. F., Jornet, J. M. & Pierobon, M. Nanonetworks: a new frontier in communications. Commun. ACM 54, 84–89 (2011).Nakano, T., Moore, M. J., Wei, F., Vasilakos, A. V. & Shuai, J. Molecular communication and networking: opportunities and challenges. IEEE Trans. Nanobiosci. 11, 135–148 (2012).Waters, C. M. & Bassler, B. L. Quorum sensing: cell-to-cell communication in bacteria. Annu. Rev. Cell Dev. Biol. 21, 319–346 (2005).Dickschat, J. S. Quorum sensing and bacterial biofilms. Nat. Prod. Rep. 27, 343–369 (2010).Kerényi, Á., Bihary, D., Venturi, V. & Pongor, S. Stability of multispecies bacterial communities: signaling networks may stabilize microbiomes. PLoS ONE 8, e57947 (2013).Gotti, C. & Clementi, F. Neuronal nicotinic receptors: from structure to pathology. Prog. Neurobiol. 74, 363–396 (2004).Betke, K. M., Wells, C. A. & Hamm, H. E. GPCR mediated regulation of synaptic transmission. Prog. Neurobiol. 96, 304–321 (2012).Qian, L., Winfree, E. & Bruck, J. Neural network computation with DNA strand displacement cascades. Nature 475, 368–372 (2011).Benenson, Y. Biomolecular computing systems: principles, progress and potential. Nat. Rev. Genet. 13, 455–468 (2012).Ball, P. Chemistry meets computing. Nature 406, 118–120 (2000).de Silva, A. P. & McClenaghan, N. D. Molecular-Scale Logic Gates. Chem. Eur. J. 10, 574–586 (2004).Condon, A. Automata make antisense. Nature 429, 351–352 (2004).Seelig, G., Soloveichik, D., Zhang, D. Y. & Winfree, E. Enzyme-free nucleic acid logic circuits. Science 314, 1585–1588 (2006).Douglas, S. M., Bachelet, I. & Church, G. M. A logic-gated nanorobot for targeted transport of molecular payloads. Science 335, 831–834 (2012).Angelos, S., Yang, Y. W., Khashab, N. M., Stoddart, J. F. & Zink, J. I. Dual-controlled nanoparticles exhibiting AND logic. J. Am. Chem. Soc. 131, 11344–11346 (2009).Liu, H. et al. Dual-responsive surfaces modified with phenylboronic acid-containing polymer brush to reversibly capture and release cancer cells. J. Am. Chem. Soc. 135, 7603–7609 (2013).Lee, J. W. & Klajn, R. Dual-responsive nanoparticles that aggregate under the simultaneous action of light and CO2 . Chem. Commun. 51, 2036–2039 (2015).Liu, D. et al. Resettable, multi-readout logic gates based on controllably reversible aggregation of gold nanoparticles. Angew. Chem. Int. Ed. 50, 4103–4107 (2011).Chitode, J. S. Communication Theory Technical Publications (2010).Wood, J. T. Communication in Our Lives Wadsworth (2009).Guardado-Alvarez, T. M., Sudha Devi, L., Russell, M. M., Schwartz, B. J. & Zink, J. I. Activation of snap-top capped mesoporous silica nanocontainers using two near-infrared photons. J. Am. Chem. Soc. 135, 14000–14003 (2013).Baeza, A., Guisasola, E., Ruiz-Hernández, E. & Vallet-Regí, M. Magnetically triggered multidrug release by hybrid mesoporous silica nanoparticles. Chem. Mater. 24, 517–524 (2012).Zhang, Z. et al. Biocatalytic release of an anticancer drug from nucleic-acids-capped mesoporous SiO2 using DNA or molecular biomarkers as triggering stimuli. ACS Nano 7, 8455–8468 (2013).Tang, F., Li, L. & Chen, D. Mesoporous silica nanoparticles: synthesis, biocompatibility and drug delivery. Adv. Mater. 24, 1504–1534 (2012).Li, Z., Barnes, J. C., Bosoy, A., Stoddart, J. F. & Zink, J. I. Mesoporous silica nanoparticles in biomedical applications. Chem. Soc. Rev. 41, 2590–2605 (2012).Coll, C., Bernardos, A., Martínez-Máñez, R. & Sancenón, F. Gated silica mesoporous supports for controlled release and signaling applications. Acc. Chem. Res. 46, 339–349 (2013).Aznar, E. et al. Gated materials for on-command release of guest molecules. Chem. Rev. 116, 561–718 (2016).Díez, P. et al. Toward the design of smart delivery systems controlled by integrated enzyme-based biocomputing ensembles. J. Am. Chem. Soc. 136, 9116–9123 (2014).Villalonga, R. et al. Enzyme-controlled sensing-actuating nanomachine based on Janus Au-mesoporous silica nanoparticles. Chem. Eur. J. 19, 7889–7894 (2013).Jerez, G., Kaufman, G., Prystai, M., Schenkeveld, S. & Donkor, K. K. Determination of thermodynamic pKa values of benzimidazole and benzimidazole derivatives by capillary electrophoresis. J. Sep. Sci. 32, 1087–1095 (2009).Sheffner, A. L. The reduction in vitro in viscosity of mucoprotein solutions by a new mucolytic agent, N-acetyl-L-cysteine. Ann. N. Y. Acad. Sci. 106, 298–310 (1963).Turkevich, J., Stevenson, P. C. & Hillier, J. A study of the nucleation and growth processes in the synthesis of colloidal gold. Discuss. Faraday Soc. 11, 55–75 (1951).Frens, G. Controlled Nucleation for the Regulation of the Particle Size in Monodisperse Gold Suspensions. Nature 241, 20–22 (1973).Yousef, F. O., Zughul, M. B. & Badwan, A. A. The modes of complexation of benzimidazole with aqueous β-cyclodextrin explored by phase solubility, potentiometric titration, 1H-NMR and molecular modeling studies. J. Incl. Phenom. Macrocycl. Chem. 57, 519–523 (2007).Sánchez, A., Díez, P., Martínez-Ruíz, P., Villalonga, R. & Pingarrón, J. M. Janus Au-mesoporous silica nanoparticles as electrochemical biorecognition-signaling system. Electrochem. Commun. 30, 51–54 (2013).Akyildiz, I. F., Pierobon, M., Balasubramaniam, S. & Koucheryavy, Y. The internet of Bio-Nano things. IEEE Commun. Mag. 53, 32–40 (2015).Sancenón, F., Pascual, L., Oroval, M., Aznar, E. & Martínez-Máñez, R. Gated silica mesoporous materials in sensing applications. ChemistryOpen 4, 418–437 (2015).Akyildiz, I. & Jornet, J. The Internet of nano-things. IEEE Wirel. Commun. 17, 58–63 (2010).Giménez, C. et al. Towards chemical communication between gated nanoparticles. Angew. Chem. Int. Ed. 53, 12629–12633 (2014).Davis, B. G., Lloyd, R. C. & Jones, J. B. Controlled site-selective glycosylation of proteins by a combined site-directed mutagenesis and chemical modification approach. J. Org. Chem. 63, 9614–9615 (1998)

Calcifications in atherosclerotic plaques and impact on plaque biomechanics

The catastrophic mechanical rupture of an atherosclerotic plaque is the underlying cause of the majority of cardiovascular events. The infestation of vascular calcification in the plaques creates a mechanically complex tissue composite. Local stress concentrations and plaque tissue strength properties are the governing parameters required to predict plaque ruptures. Advanced imaging techniques have permitted insight into fundamental mechanisms driving the initiating inflammatory-driven vascular calcification of the diseased intima at the (sub-) micron scale and up to the macroscale. Clinical studies have potentiated the biomechanical relevance of calcification through the derivation of links between local plaque rupture and specific macrocalcification geometrical features. The clinical implications of the data presented in this review indicate that the combination of imaging, experimental testing, and computational modelling efforts are crucial to predict the rupture risk for atherosclerotic plaques. Specialised experimental tests and mo