MIMO Antennas: Design Approaches, Techniques and Applications

The excessive use of digital platforms with rapidly increasing users in the wireless domain enforces communication systems to provide information with high data rates, high reliability and strong transmission connection quality. Wireless systems with single antenna elements are not able to accomplish the desired needs. Therefore, multiple-input multiple-output (MIMO) antennas are getting more attention in modern high-speed communication systems and play an essential part in the current generation of wireless technology. However, along with their ability to significantly increase channel capacity, it is a challenge to achieve an optimal isolation in a compact size for fifth-generation (5G) terminals. Portable devices, automobiles, handheld gadgets, smart phones, wireless sensors, radio frequency identification and other applications use MIMO antenna systems. In this review paper, the fundamentals of MIMO antennas, the performance parameters of MIMO antennas, and different design approaches and methodologies are discussed to realize the three most commonly used MIMO antennas, i.e., ultra-wideband (UWB), dual-band and circularly polarized antennas. The recent MIMO antenna design approaches with UWB, dual band and circularly polarized characteristics are compared in terms of their isolation techniques, gain, efficiency, envelope correlation coefficient (ECC) and channel capacity loss (CCL). This paper is very helpful to design suitable MIMO antennas applicable in UWB systems, satellite communication systems, GSM, Bluetooth, WiMAX, WLAN and many more. The issues with MIMO antenna systems in the indoor environment along with possible solutions to improve their performance are discussed. The paper also focuses on the applications of MIMO characteristics for future sixth-generation (6G) technology

Monomerization alters the dynamics of the lid region in <i>Campylobacter jejuni</i> CstII: an MD simulation study

<p>CstII, a bifunctional (α2,3/8) sialyltransferase from <i>Campylobacter jejuni</i>, is a homotetramer<i>.</i> It has been reported that mutation of the interface residues Phe121 (F121D) or Tyr125 (Y125Q) leads to monomerization and partial loss of enzyme activity, without any change in the secondary or tertiary structures. MD simulations of both tetramer and monomer, with and without bound donor substrate, were performed for the two mutants and WT to understand the reasons for partial loss of activity due to monomerization since the active site is located within each monomer. RMSF values were found to correlate with the crystallographic B-factor values indicating that the simulations are able to capture the flexibility of the molecule effectively. There were no gross changes in either the secondary or tertiary structure of the proteins during MD simulations. However, interface is destabilized by the mutations, and more importantly the flexibility of the lid region (Gly152-Lys190) is affected. The lid region accesses three major conformations named as open, intermediate, and closed conformations. In both Y121Q and F121D mutants, the closed conformation is accessed predominantly. In this conformation, the catalytic base His188 is also displaced. Normal mode analysis also revealed differences in the lid movement in tetramer and monomer. This provides a possible explanation for the partial loss of enzyme activity in both interface mutants. The lid region controls the traffic of substrates and products in and out of the active site, and the dynamics of this region is regulated by tetramerization. Thus, this study provides valuable insights into the role of loop dynamics in enzyme activity of CstII.</p

Human -acetylglucosaminyltransferase II substrate recognition uses a modular architecture that includes a convergent exosite

Asn-linked oligosaccharides are extensively modified during transit through the secretory pathway, first by trimming of the nascent glycan chains and subsequently by initiating and extending multiple oligosaccharide branches from the trimannosyl glycan core. Trimming and branching pathway steps are highly ordered and hierarchal based on the precise substrate specificities of the individual biosynthetic enzymes. A key committed step in the synthesis of complex-type glycans is catalyzed by N-acetylglucosaminyltransferase II (MGAT2), an enzyme that generates the second GlcNAcβ1,2- branch from the trimannosyl glycan core using UDP-GlcNAc as the sugar donor. We determined the structure of human MGAT2 as a Mn2+-UDP donor analog complex and as a GlcNAcMan3GlcNAc2-Asn acceptor complex to reveal the structural basis for substrate recognition and catalysis. The enzyme exhibits a GT-A Rossmann-like fold that employs conserved divalent cation-dependent substrate interactions with the UDP-GlcNAc donor. MGAT2 interactions with the extended glycan acceptor are distinct from other related glycosyltransferases. These interactions are composed of a catalytic subsite that binds the Man-α1,6- monosaccharide acceptor and a distal exosite pocket that binds the GlcNAc-β1,2Man-α1,3Manβ- substrate "recognition arm." Recognition arm interactions are similar to the enzyme-substrate interactions for Golgi α-mannosidase II, a glycoside hydrolase that acts just before MGAT2 in the Asn-linked glycan biosynthetic pathway. These data suggest that substrate binding by MGAT2 employs both conserved and convergent catalytic subsite modules to provide substrate selectivity and catalysis. More broadly, the MGAT2 active-site architecture demonstrates how glycosyltransferases create complementary modular templates for regiospecific extension of glycan structures in mammalian cells

Human -acetylglucosaminyltransferase II substrate recognition uses a modular architecture that includes a convergent exosite

Asn-linked oligosaccharides are extensively modified during transit through the secretory pathway, first by trimming of the nascent glycan chains and subsequently by initiating and extending multiple oligosaccharide branches from the trimannosyl glycan core. Trimming and branching pathway steps are highly ordered and hierarchal based on the precise substrate specificities of the individual biosynthetic enzymes. A key committed step in the synthesis of complex-type glycans is catalyzed by N-acetylglucosaminyltransferase II (MGAT2), an enzyme that generates the second GlcNAcβ1,2- branch from the trimannosyl glycan core using UDP-GlcNAc as the sugar donor. We determined the structure of human MGAT2 as a Mn2+-UDP donor analog complex and as a GlcNAcMan3GlcNAc2-Asn acceptor complex to reveal the structural basis for substrate recognition and catalysis. The enzyme exhibits a GT-A Rossmann-like fold that employs conserved divalent cation-dependent substrate interactions with the UDP-GlcNAc donor. MGAT2 interactions with the extended glycan acceptor are distinct from other related glycosyltransferases. These interactions are composed of a catalytic subsite that binds the Man-α1,6- monosaccharide acceptor and a distal exosite pocket that binds the GlcNAc-β1,2Man-α1,3Manβ- substrate "recognition arm." Recognition arm interactions are similar to the enzyme-substrate interactions for Golgi α-mannosidase II, a glycoside hydrolase that acts just before MGAT2 in the Asn-linked glycan biosynthetic pathway. These data suggest that substrate binding by MGAT2 employs both conserved and convergent catalytic subsite modules to provide substrate selectivity and catalysis. More broadly, the MGAT2 active-site architecture demonstrates how glycosyltransferases create complementary modular templates for regiospecific extension of glycan structures in mammalian cells

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Not AvailableWeather based pest forecasts form an essential component of integrated pest management (IPM). PESTPREDICT is a mobile application developed using Java and Android version 4.1 (Jelly Bean) in Eclipse Juno framework for weather based predictions of insect pests and diseases of Rice, Pigeonpea, Groundnut and Tomato developed based on field data on pests and weather accrued through ICT based pest surveillance under National Innovation in Climate Resilient Agriculture. Models of pest forecasts developed using approaches ranging from simple thumb rules to sophisticated statistical models for 25 locations across India have been built in the mobile application. In Pest Prediction Empirical Model Based System [PESTPREDICT - EMS (kharif)] user can get predictions of 29 insects, 24 diseases and two generalist predators (coccinellids and spiders) across crops (locations) of rice (6), pigeonpea (6), groundnut(5) and tomato across 11 States by providing inputs of weather associated with model equations of kharif. PESTPREDICT-EMS (rabi) offers prediction of insect pests and diseases of rabi groundnut for locations of Anantapur (AP), Junagadh (GJ), Dharwad (KA) and Cuddalore (TN). Rule based system predicting largely rice insect pests, Spodoptera litura of groundnut and early blight of tomato (PESTPREDICT-RBS) are built in the mobileapp. PESTPREDICT assists researchers, extension personnel of agriculture and farmers to get location specific forecasts of desired insect pest(s) or disease(s) for their effective management on target crops. PESTPREDICT reduces calculation efforts and provides an instant and extempore framework for use of developed prediction models. The open source application also facilitates easy prediction of insect pest dynamics for the current and future climate scenarios when the relevant values of temperature relating to the emission scenarios are available. Currently this application is aimed for field use to predict the incidence of pests of four target crops of the real time pest dynamic study locations under National Innovations in Climate Resilient Agriculture (NICRA) for the purposes of issuing ‘pest alerts’ at times of high severity or above economic threshold levels.Not Availabl

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Not AvailableFurnishes information on Pestpredict app developed for android phones. Covers profile of insect pests and disease for prediction, how to install it, How to use it and way forward besides supplementary informationNot Availabl