Note: Frequency-conversion photonic Doppler velocimetry with an inverted circulator

Photonic Doppler velocimetry (PDV) is a fiber-based interferometer used in dynamic compression research. Conventional PDV systems are simple to construct but do not perform well in all measurement conditions, while universal PDV systems that support many different configurations are complex and expensive. A simpler approach is the use of external, inverted circulators which can be added and removed in a modular fashion. This technique permits frequency-conversion measurements with a conventional PDV system. Using a correction to remove baseline effects, frequency conversion systems can resolve low velocity transients that conventional PDV cannot.     

Evaluation of epoxy resin sealer after three root canal filling techniques by confocal laser scanning microscopy

The aim of this study was to evaluate the penetration of endodontic sealer into the dentin tubules, the integrity of the sealer layer perimeter, and the sealer area at the apical third after different filling techniques by confocal laser scanning microscopy (CLSM). Forty‐five mandibular premolars were mechanically prepared with ProTaper files, until F5 file. Thereafter, they were filled with an epoxy‐resin sealer (AH Plus) mixed with Rhodamine B dye (0.1% proportion) and allocated in three groups: Group 1, single master cone; Group 2, cold lateral compaction; and Group 3, Thermafil. For confocal laser scanning microscopy analysis, the specimens were transversely sectioned at 4 mm from the apex. The images at ×10 and ×40 were analyzed by Imagetool 3.0 software. Significant differences were not found among the three experimental groups according the dentin‐impregnate area by the sealer (P = 0.68) and between the sealer and root canal perimeter (P = 0.18). However, root canal filling techniques were significantly different when apical sealer areas were compared (P = 0.001). Thermafil group showed smaller sealer areas (8.09%) while cold lateral compaction and gutta‐percha master cone showed similar areas (17.37 and 21.18%, respectively). The dentin‐impregnated area was not dependent on the root canal filling technique. Single master cone, cold lateral condensation and Thermafil techniques presented integrity of the sealer perimeter close to 100% and Thermafil resulted in a significantly thinner sealer layer. Microsc. Res. Tech. 75:1277–1280, 2012. © 2012 Wiley Periodicals, Inc.     

Systemically alendronate was incorporated into dental tissues but did not cause morphological or mechanical changes in rats teeth

This study evaluated the effect of the systemic use of sodium alendronate in rats in vivo. Forty‐five Wistar rats aged 36 to 42 days and weighing 200 to 230 g were randomly assigned to a control group (n = 20), which received distilled water, and an experimental group (n = 25), which received 2 weekly doses of 1 mg/kg of chemically pure sodium alendronate. The animals were killed after 60 days of treatment. The tibias were removed for analysis of bone mineral density by dual‐energy X‐ray absorptiometry (DXA). Then, the maxillary incisors were extracted for analysis of the mineralized dental tissues using fluorescence spectroscopy (FS), scanning electron microscopy (SEM), bright field microscopy (BFM), and cross‐sectional microhardness (CSMH) testing. DXA and CSMH data were subjected to statistical analysis by Kruskal‐Wallis test (5% significance level). The experimental group presented higher bone mineral density than the control group by DXA. FS analysis revealed presence of alendronate in the mineralized dental tissues of the specimens of the experimental group. Significant morphological differences were not found by SEM and BFM. Enamel and dentin (100 and 300 μm from the dentinoenamel junction) CSMH data did not show significant difference between the control and experimental groups. Based on the obtained results, we conclude that while alendronate increased the bone mineral density and was incorporated into the mineralized dental tissues it did not cause significant alterations in the morphology and microhardness of rat incisor enamel and dentin. Microsc. Res. Tech. 75:1265–1271, 2012. © 2012 Wiley Periodicals, Inc.     

Analysis of the interface and bond strength of resin-based endodontic cements to root dentin

This study evaluated by scanning electron microscopy the interface between root dentin and resin cements, with or without additional application of a dual-cured one-step self-etching dentin adhesive. In addition, the push-out bond strength of these materials to dentin was evaluated. Root canals of 50 maxillary human canines were subjected to biomechanical preparation and randomly assigned into five groups (n = 10) according to the obturation employed: I. AH Plus/gutta-percha; II. Endo-REZ/gutta-percha; III. Epiphany SE/Resilon; IV. Endo-REZ/gutta-percha + adhesive; and V. Epiphany SE/Resilon + adhesive. After obturation, two cross sections of 1.0 mm of each third of the root were obtained and analyzed by SEM and push-out. Data were analyzed by Kruskal-Wallis, Two-way ANOVA and Tukey's HSD tests (α = 5%). Significant differences occurred between scores for gap parameters and tags; greater tag formation resulted for Epiphany SE (P < 0.05). There were also significant differences between groups for the bond strength. AH Plus (1.24 ± 0.70) showed higher values (P < 0.05) compared to groups II (0,17 ± 0.19), III (0.10 ± 0.06), IV (0.09 ± 0.08), and V (0.06 ± 0.03), which were statistically similar (P > 0.05). There was no significant difference between the root thirds (P > 0.05). It was concluded that the use of a self-etching adhesive system did not improve the adhesion of resin-based sealers to dentin and that AH Plus showed better bond strength when compared to other cements.     

Tropical linear-fractional programming and parametric mean payoff games

Tropical polyhedra have been recently used to represent disjunctive invariants in static analysis. To handle larger instances, tropical analogues of classical linear programming results need to be developed. This motivation leads us to study the tropical analogue of the classical linear-fractional programming problem. We construct an associated parametric mean payoff game problem, and show that the optimality of a given point, or the unboundedness of the problem, can be certified by exhibiting a strategy for one of the players having certain infinitesimal properties (involving the value of the game and its derivative) that we characterize combinatorially. We use this idea to design a Newton-like algorithm to solve tropical linear-fractional programming problems, by reduction to a sequence of auxiliary mean payoff game problems.     

Texture descriptor based on partially self-avoiding deterministic walker on networks

Texture image analysis is an important field of investigation that has attracted the attention from computer vision community in the last decades. In this paper, a novel approach for texture image analysis is proposed by using a combination of graph theory and partially self-avoiding deterministic walks. From the image, we build a regular graph where each vertex represents a pixel and it is connected to neighboring pixels (pixels whose spatial distance is less than a given radius). Transformations on the regular graph are applied to emphasize different image features. To characterize the transformed graphs, partially self-avoiding deterministic walks are performed to compose the feature vector. Experimental results on three databases indicate that the proposed method significantly improves correct classification rate compared to the state-of-the-art, e.g. from 89.37% (original tourist walk) to 94.32% on the Brodatz database, from 84.86% (Gabor filter) to 85.07% on the Vistex database and from 92.60% (original tourist walk) to 98.00% on the plant leaves database. In view of these results, it is expected that this method could provide good results in other applications such as texture synthesis and texture segmentation.     

Return loss and crosstalk mitigation in coupled vias for modern high‐speed packaging

A method for mitigating the return loss and crosstalk corresponding to coupled vias is presented in this article. The method is based on selecting the proper dimensions for the antipad holes related to vias as well as the most adequate distribution of the ground vias, which allows to simultaneously reducing impedance mismatch and undesirable via coupling. The usefulness of the method is demonstrated by improving the performance of a 2 × 3 array of six signal vias. As a result, return loss levels below ?45 dB and crosstalk levels below ?40 dB are obtained in the 0–50 GHz frequency range. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

The Construction-Integration framework: a means to diminish bias in LSA-based call routing

Semantic technology is commonly used for two purposes in the field of IVR (Interactive Voice Response). The first is to correct the output of voice recognition devices based on coherence with a context. The second is to perform what is referred to as “call routing”, requiring technology that categorizes utterances and returns a list of the most credible routes. Our paper focuses on the latter, aiming to use the Latent Semantic Analysis (LSA henceforth) computational model (Deerwester et al. in J. Am. Soc. Inf. Sci. 41:391–407, 1990) together with the Construction-Integration model (C-I henceforth), a psycholinguistically motivated algorithm (Kintsch in Int. J. Psychol. 33(6):411–420, 1998), to interpret, manage and successfully route user requests in an efficient and reliable manner. By efficient we mean that training is unnecessary when the destination model is altered, and exhaustive labeling of all utterances is not required, concentrating instead only on some sample destinations. By reliable we mean that the construction-integration algorithm attenuates the risks from intra-destination variability and word saliency. Technical and theoretical aspects are discussed. In addition, some destination assignment methods are tested and debated.     

NEGOSEIO: A framework for negotiations toward Sustainable Enterprise Interoperability

With the rise of the Internet, competitiveness is pressuring enterprises to build better solutions with fewer resources, following new trends and supporting new platforms and methodologies. On the other hand, legislation and regulations are updating frequently and deeply, and demanding rapid compliance from enterprises. These frequent business changes shake all the interoperability links between the enterprises, leading to periods of adaptation where business operation is not possible. The urge to rapidly regain interoperability often leads to unfounded, poorly-chosen solutions, which lead to inefficiency and rework. This paper proposes that the best way to have a strong interoperable environment is to perform constant, periodic maintenance operations in order to adapt enterprises to their surrounding ecosystem. It introduces NEGOSEIO, a framework that promotes continuous improvement and adaptation towards the management of interoperability on enterprise systems, and which has negotiations as a core mechanism to handle inconsistencies and solutions for the detected interoperability problems. Following this approach, enterprises shall become more adaptable to changes and external factors, consequently developing resilient and efficient interactions with its supply chain. The paper validates the framework with its application in a real business case of aerospace mission design on the European Space Agency (ESA).