Massive MIMO-based system analysis and comparison with MIMO based-systems

The thesis is focused on introducing basic MIMO-based and Massive MIMO-based systems and their possible benefits. Then going through the implementation options that we have, according to 3GPP standards, for 5G systems and how the transition is done from a non-standalone 5G RAN to a completely standalone 5G RAN. Having introduced the above-mentioned subjects and providing some definition of telecommunications principles, we move forward to a more technical analysis of the Capacity, Throughput, Power consumption, and Costs. Comparing all the mentioned parameters between a Massive-MIMO-based system and a MIMO-based system. In the analysis of power consumption and costs, we also introduce the concept of virtualization and its benefits in terms of both power and costs. Finally, we try to justify a trade-off between having a more reliable system with a high capacity and throughput while keeping the costs as low as possible.

Study of an advanced transport system exploiting magnetic levitation: the Beckhoff XPlanar

The transport system is one of the most important components to be chosen in the design of an automatic machine. There is a wide variety of different choices that can be made in picking this element, each one having its own strengths and its own drawbacks. If it is desired to obtain some elaborate behaviour from the transport system, it is a good idea to think about some flexible and advanced solutions. Among these transport systems, the newest is the Beckhoff XPlanar. This transport system exploits magnetic levitation to move some passive magnetic movers on a completely customizable plane, in an entirely contact-free way. This provides a fast, clean, and noiseless motion, which is extremely desirable in a modern automatic machine. The purpose of this Thesis is to analyse the potentialities and the problems of this new device, starting from the basics. After having presented in detail the topic, an analysis on the hardware components needed to build this system is performed. Then, it is conducted a study on the concepts needed to know how to build a controller having the purpose of dealing with this system. After that, the various types of motion are studied and executed and, later on, some experiments on the real kit are carried out. These studies start from the diagnostic and involve other analyses that are used to test the limits of this transport system. In performing these analyses, it is noticed how the kit presents some problems in reaching the limits of the dynamics. Finally, two different types of station cycle are implemented, which are useful to get a rough idea on the potentialities of this new advanced transport system.

Solid Lipid Nanoparticles As Nucleic Acid Delivery System: Properties And Molecular Mechanisms.

Solid lipid nanoparticles (SLNs) have been proposed in the 1990s as appropriate drug delivery systems, and ever since they have been applied in a wide variety of cosmetic and pharmaceutical applications. In addition, SLNs are considered suitable alternatives as carriers in gene delivery. Although important advances have been made in this particular field, fundamental knowledge of the underlying mechanisms of SLN-mediated gene delivery is conspicuously lacking, an imperative requirement in efforts aimed at further improving their efficiency. Here, we address recent advances in the use of SLNs as platform for delivery of nucleic acids as therapeutic agents. In addition, we will discuss available technology for conveniently producing SLNs. In particular, we will focus on underlying molecular mechanisms by which SLNs and nucleic acids assemble into complexes and how the nucleic acid cargo may be released intracellularly. In discussing underlying mechanisms, we will, when appropriate, refer to analogous studies carried out with systems based on cationic lipids and polymers, that have proven useful in the assessment of structure-function relationships. Finally, we will give suggestions for improving SLN-based gene delivery systems, by pointing to alternative methods for SLNplex assembly, focusing on the realization of a sustained nucleic acid release.

Self-etch Adhesive Systems: A Literature Review.

This paper presents the state of the art of self-etch adhesive systems. Four topics are shown in this review and included: the historic of this category of bonding agents, bonding mechanism, characteristics/properties and the formation of acid-base resistant zone at enamel/dentin-adhesive interfaces. Also, advantages regarding etch-and-rinse systems and classifications of self-etch adhesive systems according to the number of steps and acidity are addressed. Finally, issues like the potential durability and clinical importance are discussed. Self-etch adhesive systems are promising materials because they are easy to use, bond chemically to tooth structure and maintain the dentin hydroxyapatite, which is important for the durability of the bonding.

Pollination Ecology Of Two Species Of Elleanthus (orchidaceae): Novel Mechanisms And Underlying Adaptations To Hummingbird Pollination.

Relationships among floral biology, floral micromorphology and pollinator behaviour in bird-pollinated orchids are important issues to understand the evolution of the huge flower diversity within Orchidaceae. We aimed to investigate floral mechanisms underlying the interaction with pollinators in two hummingbird-pollinated orchids occurring in the Atlantic forest. We assessed floral biology, nectar traits, nectary and column micromorphologies, breeding systems and pollinators. In both species, nectar is secreted by lip calli through spaces between the medial lamellar surfaces of epidermal cells. Such form of floral nectar secretion has not been previously described. Both species present functional protandry and are self-compatible yet pollinator-dependent. Fruit sets in hand-pollination experiments were more than twice those under natural conditions, evidencing pollen limitation. The absence of fruit set in interspecific crosses suggests the existence of post-pollination barriers between these synchronopatric species. In Elleanthus brasiliensis, fruits resulting from cross-pollination and natural conditions were heavier than those resulting from self-pollination, suggesting advantages to cross-pollination. Hummingbirds pollinated both species, which share at least one pollinator species. Species differences in floral morphologies led to distinct pollination mechanisms. In E. brasiliensis, attachment of pollinaria to the hummingbird bill occurs through a lever apparatus formed by an appendage in the column, another novelty to the knowledge of orchids. In E. crinipes, pollinaria attachment occurs by simple contact with the bill during insertion into the flower tube, which fits tightly around the bill. The novelties described here illustrate the overlooked richness in ecology and morphophysiology in Orchidaceae. This article is protected by copyright. All rights reserved.

Engineered Nanoparticles And Organic Matter: A Review Of The State-of-the-art.

Growth in the development and production of engineered nanoparticles (ENPs) in recent years has increased the potential for interactions of these nanomaterials with aquatic and terrestrial environments. Carefully designed studies are therefore required in order to understand the fate, transport, stability, and toxicity of nanoparticles. Natural organic matter (NOM), such as the humic substances found in water, sediment, and soil, is one of the substances capable of interacting with ENPs. This review presents the findings of studies of the interaction of ENPs and NOM, and the possible effects on nanoparticle stability and the toxicity of these materials in the environment. In addition, ENPs and NOM are utilized for many different purposes, including the removal of metals and organic compounds from effluents, and the development of new electronic sensors and other devices for the detection of active substances. Discussion is therefore provided of some of the ways in which NOM can be used in the production of nanoparticles. Although there has been an increase in the number of studies in this area, further progress is needed to improve understanding of the dynamic interactions between ENPs and NOM.

Short-term Physiological Changes In Roots And Leaves Of Sugarcane Varieties Exposed To H2o2 In Root Medium.

The aim of this study was to evaluate the differential sensitivity of sugarcane genotypes to H2O2 in root medium. As a hypothesis, the drought tolerant genotype would be able to minimize the oxidative damage and maintain the water transport from roots to shoots, reducing the negative effects on photosynthesis. The sugarcane genotypes IACSP94-2094 (drought tolerant) and IACSP94-2101 (drought sensitive) were grown in a growth chamber and exposed to three levels of H2O2 in nutrient solution: control; 3mmolL(-1) and 80mmolL(-1). Leaf gas exchange, photochemical activity, root hydraulic conductance (Lr) and antioxidant metabolism in both roots and leaves were evaluated after 15min of treatment with H2O2. Although, root hydraulic conductance, stomatal aperture, apparent electron transport rate and instantaneous carboxylation efficiency have been reduced by H2O2 in both genotypes, IACSP94-2094 presented higher values of those variables as compared to IACSP94-2101. There was a significant genotypic variation in relation to the physiological responses of sugarcane to increasing H2O2 in root tissues, being root changes associated with modifications in plant shoots. IACSP94-2094 presented a root antioxidant system more effective against H2O2 in root medium, regardless H2O2 concentration. Under low H2O2 concentration, water transport and leaf gas exchange of IACSP94-2094 were less affected as compared to IACSP94-2101. Under high H2O2 concentration, the lower sensitivity of IACSP94-2094 was associated with increases in superoxide dismutase activity in roots and leaves and increases in catalase activity in roots. In conclusion, we propose a general model of sugarcane reaction to H2O2, linking root and shoot physiological responses.

Evaluating resin-enamel bonds by microshear and microtensile bond strength tests: effects of composite resin

OBJECTIVES: The aims of this study were to evaluate the effect of resin composite (Filtek Z250 and Filtek Flow Z350) and adhesive system [(Solobond Plus, Futurabond NR (VOCO) and Adper Single Bond (3M ESPE)] on the microtensile (μTBS) and microshear bond strength (μSBS) tests on enamel, and to correlate the bond strength means between them. MATERIAL AND METHODS: Thirty-six extracted human molars were sectioned to obtain two tooth halves: one for μTBS and the other one for μSBS. Adhesive systems and resin composites were applied to the enamel ground surfaces and light-cured. After storage (37(0)C/24 h) specimens were stressed (0.5 mm/min). Fracture modes were analyzed under scanning electron microscopy. The data were analyzed using two-way ANOVA and Tukey's test (α=0.05). RESULTS: The correlation between tests was estimated with Pearson's product-moment correlation statistics (α =0.05). For both tests only the main factor resin composite was statistically significant (p<0.05). The correlation test detected a positive (r=0.91) and significant (p=0.01) correlation between the tests. CONCLUSIONS: The results were more influenced by the resin type than by the adhesives. Both microbond tests seem to be positive and linearly correlated and can therefore lead to similar conclusions.

Complex networks: the key to systems biology

Though introduced recently, complex networks research has grown steadily because of its potential to represent, characterize and model a wide range of intricate natural systems and phenomena. Because of the intrinsic complexity and systemic organization of life, complex networks provide a specially promising framework for systems biology investigation. The current article is an up-to-date review of the major developments related to the application of complex networks in biology, with special attention focused on the more recent literature. The main concepts and models of complex networks are presented and illustrated in an accessible fashion. Three main types of networks are covered: transcriptional regulatory networks, protein-protein interaction networks and metabolic networks. The key role of complex networks for systems biology is extensively illustrated by several of the papers reviewed.