Tubular dentin sealer penetration after different final irrigation protocols: A confocal laser scanning microscopy study

The aim of this study was to evaluate tubular dentin sealer penetration, comparing different final irrigation protocols using a conventional needle (CONV), EndoActivator system (EAS), EndoVac system (EVS), and ultrasound (PUI). Initially, fifty‐two first maxillary molars with a single canal in the palatal root, without abrupt curvatures, resorptive processes, or previous endodontic treatment were selected for this study. Then, the crowns were sectioned to obtain palatal roots 15 mm in length. The root canals were prepared with the ProTaper Universal System and irrigated with 5% NaOCl. Afterwards, the specimens were divided into four groups (n. 13), according to the final irrigation protocol: CONV, EAS, EVS, and PUI. After filling, slices at 3 mm and 5 mm from the apex were obtained for analysis by confocal laser scanning microscopy. Two‐way comparisons between the groups and the levels were performed with Games Howell's test (p < .05). Tubular dentin sealer penetration was higher at 5 mm compared with 3 mm from the apex (p < .05). The EAS group showed a higher percentage of tubular dentin sealer penetration, compared with the CONV group, at both levels. At 3 mm, there was no statistically significant difference among EAS, EVS, and PUI; however, these groups showed better performance, compared with the CONV group. At 5 mm, there was no statistically significant difference between the EAS and EVS groups, but both showed higher sealer penetration than the PUI group (p < .05). The EAS and EVS groups achieved better degrees of tubular dentin sealer penetration, compared with the other groups.     

Structural and thermal behavior of 45S5 Bioglass®-based compositions containing alumina and strontium

The present research exposes the influence of 2 mol% of Al₂O₃ and 2 mol% SrO in 45S5 Bioglass^®-based compositions. Four compositions were produced to elucidate the difference in how both oxides influence structure and thermal behavior separately and their synergy when together. Thermal properties, crystallization tendency, and sintering behavior was evaluated by differential scanning calorimetry, hot stage microscopy, and dilatometry. Changes of medium-range structures were characterized by Qⁿ distribution of Raman spectroscopy and evaluation of ³¹P, ²⁷Al, ²³Na, and ²⁹Si environment obtained by magic angle spinning nuclear magnetic resonance. Despite Qⁿ distribution was predominantly Q² in all samples, the composition criteria used enabled improved processing and stabilibity characteristics. The addition of Al₂O₃ and SrO promoted larger sinterability parameter (S_c) which indicates better sintering behavior, the glass stability against crystallization doubled (K_H) compared to 45S5 and the processing window enlarged from 106 to 171.     

Single-step creation of localized Delaunay triangulations

A localized Delaunay triangulation owns the following interesting properties for sensor and wireless ad hoc networks: it can be built with localized information, the communication cost imposed by control information is limited, and it supports geographical routing algorithms that offer guaranteed convergence. This paper presents two localized algorithms, fast localized Delaunay triangulation 1 (FLDT1) and fast localized Delaunay triangulation 2 (FLDT2), that build a graph called planar localized Delaunay triangulation, PLDel, known to be a good spanner of the Unit Disk Graph, UDG. Our algorithms improve previous algorithms with similar theoretical bounds in the following aspects: unlike previous work, FLDT1 and FLDT2 build PLDel in a single communication step, maintaining a communication cost of O(n log n), which is within a constant of the optimal. Additionally, we show that FLDT1 is more robust than previous triangulation algorithms, because it does not require the strict UDG connectivity model to work. The small signaling cost of our algorithms allows us to improve routing performance, by efficiently using the PLDel graph instead of sparser graphs, like the Gabriel or the Relative Neighborhood graphs.     

Dimensional Effects on Magnetic Properties of Fe–Si Steels Due to Laser and Mechanical Cutting

Microstructural deterioration near the cut line and presence of residual stresses both affect the magnetic properties of cut parts. In this paper, the differences between microstructural deterioration resulting from mechanical and laser cutting as well as the sample size effects observed upon hysteresis will be discussed. It will be shown that the underlying mechanism for changes in magnetic properties due to mechanical cutting is distinct from that of laser cutting.      

Development of an Educational Environment for Simulating Multistatic UWB Radars for Locating an Intruder Inside Indoor Environment

This work describes a educational tool developed in Java language for simulating a multi-static radar. This radar is used to identify the presence of an intruder inside a residence. In order to obtain high resolution, the radar operates with ultra-wideband pulses (Gaussian monocycle), which have maximum spectral amplitude at 1 GHz and half power bandwidth of approximately 1 GHz. For the estimation of the intruder's position, the optimization technique particle swarm optimization (PSO) is employed. The simulator allows that the users define the parameters to be used by the radar and obtain the estimation of the intruder's position. Besides that, the software automatically generates animations of the wave propagation inside the residence, graphics of the signal at the receiving points and a final report with all the information related to the simulations.     

Palynological and physicochemical data characterisation of honeys produced in the Entre‐Douro e Minho region of Portugal

Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physicochemical properties may increase the commercial value of these products. The characteristics of thirty‐one honeys produced in the Entre‐Douro e Minho region in Portugal were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural contain, apparent sucrose, reducing sugars and diastase activity) were determined. The samples were found to meet international honey specifications. The present study found a linear regression between the ash content of honeys and their specific conductivity. Five samples are listed as Eucalyptus honey, one sample as Citrus honey, and twenty‐five samples as multifloral honeys. Of the total, 87.1% exceeded the quality parameters and should be labelled as ‘virgin’ honey.     

Self-organizing continuous attractor networks and path integration: one-dimensional models of head direction cells

Some neurons encode information about the orientation or position of an animal, and can maintain their response properties in the absence of visual input. Examples include head direction cells in rats and primates, place cells in rats and spatial view cells in primates. 'Continuous attractor' neural networks model these continuous physical spaces by using recurrent collateral connections between the neurons which reflect the distance between the neurons in the state space (e.g. head direction space) of the animal. These networks maintain a localized packet of neuronal activity representing the current state of the animal. We show how the synaptic connections in a one-dimensional continuous attractor network (of for example head direction cells) could be self-organized by associative learning. We also show how the activity packet could be moved from one location to another by idiothetic (self-motion) inputs, for example vestibular or proprioceptive, and how the synaptic connections could self-organize to implement this. The models described use 'trace' associative synaptic learning rules that utilize a form of temporal average of recent cell activity to associate the firing of rotation cells with the recent change in the representation of the head direction in the continuous attractor. We also show how a nonlinear neuronal activation function that could be implemented by NMDA receptors could contribute to the stability of the activity packet that represents the current state of the animal.     

Self-organizing continuous attractor networks and path integration: two-dimensional models of place cells

Single-neuron recording studies have demonstrated the existence of neurons in the hippocampus which appear to encode information about the place where a rat is located, and about the place at which a macaque is looking. We describe 'continuous attractor' neural network models of place cells with Gaussian spatial fields in which the recurrent collateral synaptic connections between the neurons reflect the distance between two places. The networks maintain a localized packet of neuronal activity that represents the place where the animal is located. We show for two related models how the representation of the two-dimensional space in the continuous attractor network of place cells could self-organize by modifying the synaptic connections between the neurons, and also how the place being represented can be updated by idiothetic (self-motion) signals in a neural implementation of path integration.     

A DUAL‐MODE ADAPTIVE ROBUST CONTROLLER APPLIED TO THE SPEED CONTROL OF A THREE‐PHASE INDUCTION MOTOR

This work presents a Dual‐Mode Adaptive Robust Controller applied to the angular shaft speed control of a three‐phase induction motor. A liaison between a Model Reference Adaptive Controller (MRAC) and a Variable Structure Model Reference Adaptive Controller (VS‐MRAC) through a tuning parameter is obtained using fuzzy logic. The basic idea of the Dual‐Mode controller is adding both the advantages of the VS‐MRAC transient behavior with the steady‐state properties of the conventional MRAC.