1000 resultados para tag formation
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of this study was to assess penetration of adhesive material in enamel bleached with 35% hydrogen peroxide using optical polarized light microscopy. Extracted human teeth were randomly assigned to 5 groups, each representing a specific time interval between bleaching and the application of an adhesive material. They were designated as: (TC) the control group-restorations in unbleached teeth; (T0) comprising restorations carried out immediately after bleaching; (T7) comprising restorations 7 days after bleaching; (T14) comprising restorations 14 days after bleaching; and (T21) comprising restorations 21 days after bleaching. Length of resin tags was measured with an Axiophot photomicroscope at a x 400 magnification, and the results subjected to an ANOVA for a comparison between groups, with a p value of < 0.05. Differences between the groups were verified using a Tukey test at a confidence level of 5%. The specimens in the control group (TC) and experimental groups T7, T14 and T21 showed better penetration of adhesive material into enamel in comparison with experimental group T0. This suggests that a gap of at least 7 days should be left between bleaching enamel with 35% hydrogen peroxide and placing adhesive bonding agents and undertaking resin composite restoration work.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objective: This confocal microscopy study evaluated the cement/dentin and cement/post interfaces along theroot canalwallswhenfiberglasspostswerebonded to dentin using different types of cements. Material & Methods: Thirty endodontically treated premolars were divided into 3 groups according to the adhesive materials used in the bonding procedure: Prime & Bond 2.1/Self Cure + Enforce, RelyX Unicem and RelyX Luting. Rhodamine B dye was incorporated in the luting materials for the cementation of the fiber glass posts (Exacto, Angelus) to dentin. Three transversal slices (apical, middle and coronal) were examined under confocal laser scanning microscopy. Statistical analysis was performed using the Kappa, Kruskal-Wallis and Dunnet tests, in a significance level of 5%. Results: The Prime & Bond 2.1/Self Cure + Enforce presented a uniform formation of tags in the dentin but gaps in the cement/dentin interface. The RelyX Unicem and RelyX Luting presented an adhesive interface with a fewer amount of gaps, but showed shorter tag formation than the Enforce system. All cements presented the same pattern of bubbles inside the cements. The RelyX Luting presented a greater amount of cracks inside the cement in comparison with the other cements in the coronal third, while no difference was observed between RelyX Unicem and Enforce. The RelyX Luting showed the lowest quantity of cement penetration into the post. Conclusion: In general, the quality of bonding interfaces of fiber posts luted to root canals was affected by both location and type of cement.
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The Triassic Argilo-Gréseux Inférieur Formation (TAG-I) is one of the principal hydrocarbon reservoirs in the Berkine Basin of Algeria. Sedimentological studies have shown that it exhibits marked spatial and temporal facies variations on both a local field scale and a regional basinal scale. This variability, combined with a lack of diagnostic flora and fauna, makes regional correlation within the unit difficult. In turn, the lack of a consistent regional stratigraphic framework hampers the comparison of the various correlation schemes devised by operators in the basin. Contrasting the TAG-I in Blocks 402 and 405a exemplifies the problems encountered when attempting regionally to define a correlation framework for the interval. Between these two blocks, a distance of approximately 200 km, there are marked changes in the style of deposition from sand-dominated, proximal fluvial systems in the SW (Block 405a, MLN, MLC, KMD and MLNW fields) to a more distal, more clay-prone system in the NE (Block 402, ROD/BRSE/BSFN, SFNE and BSF fields). A chemostratigraphic study of the TAG-I in these two blocks has allowed a four-fold correlation framework to be defined, where each chemostratigraphic package has distinctive geochemical features. Chemostratigraphic Package 10, the oldest unit, lies above the Hercynian Unconformity, but beneath a geochemically identifiable hiatal surface. Chemostratigraphic Package 20 lies above the hiatal surface but is separated from the overlying packages by a mineralogical change identifiable in both claystone and sandstone geochemistry. Chemostratigraphic Packages 30 and 40 are chemically somewhat similar, but are separated by a regional event interpreted as a period of dolocrete and lacustrine development. By combining the geochemical differentiation of the units and recognition of their stratal boundaries, it is possible to define a correlation for the TAG-I between Blocks 402 and 405a. The proposed correlation between the two blocks suggests that the northern parts of Block 405a may have been occupied by a spur or subsidiary channel from the main SW–NE-trending fluvial system, resulting in one of the chemically defined packages being demonstrably absent in the MLNW, MLN, KMD and MLC fields when compared with the other areas of the study.
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In this paper we address the problem of forming procurement networks for items with value adding stages that are linearly arranged. Formation of such procurement networks involves a bottom-up assembly of complex production, assembly, and exchange relationships through supplier selection and contracting decisions. Recent research in supply chain management has emphasized that such decisions need to take into account the fact that suppliers and buyers are intelligent and rational agents who act strategically. In this paper, we view the problem of Procurement Network Formation (PNF) for multiple units of a single item as a cooperative game where agents cooperate to form a surplus maximizing procurement network and then share the surplus in a fair manner. We study the implications of using the Shapley value as a solution concept for forming such procurement networks. We also present a protocol, based on the extensive form game realization of the Shapley value, for forming these networks.
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A key step in the triacylglycerol (TAG) biosynthetic pathway is the final acylation of diacylglycerol (DAG) by DAG acyltransferase. In silico analysis has revealed that the DCR (defective in cuticular ridges) (At5g23940) gene has a typical HX4D acyltransferase motif at the N-terminal end and a lipid binding motif VX(2)GF at the middle of the sequence. To understand the biochemical function, the gene was overexpressed in Escherichia coli, and the purified recombinant protein was found to acylate DAG specifically in an acyl-CoA-dependent manner. Overexpression of At5g23940 in a Saccharomyces cerevisiae quadruple mutant deficient in DAG acyltransferases resulted in TAG accumulation. At5g23940 rescued the growth of this quadruple mutant in the oleate-containing medium, whereas empty vector control did not. Lipid particles were localized in the cytosol of At5g23940-transformed quadruple mutant cells, as observed by oil red O staining. There was an incorporation of 16-hydroxyhexadecanoic acid into TAG in At5g23940-transformed cells of quadruple mutant. Here we report a soluble acyl-CoA-dependent DAG acyltransferase from Arabidopsis thaliana. Taken together, these data suggest that a broad specific DAG acyltransferase may be involved in the cutin as well as in the TAG biosynthesis by supplying hydroxy fatty acid.
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A team of unmanned aerial vehicles (UAVs) with limited communication ranges and limited resources are deployed in a region to search and destroy stationary and moving targets. When a UAV detects a target, depending on the target resource requirement, it is tasked to form a coalition over the dynamic network formed by the UAVs. In this paper, we develop a mechanism to find potential coalition members over the network using principles from internet protocol and introduce an algorithm using Particle Swarm Optimization to generate a coalition that destroys the target is minimum time. Monte-Carlo simulations are carried out to study how coalition are formed and the effects of coalition process delays.
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In this paper we address the problem of forming procurement networks for items with value adding stages that are linearly arranged. Formation of such procurement networks involves a bottom-up assembly of complex production, assembly, and exchange relationships through supplier selection and contracting decisions. Research in supply chain management has emphasized that such decisions need to take into account the fact that suppliers and buyers are intelligent and rational agents who act strategically. In this paper, we view the problem of procurement network formation (PNF) for multiple units of a single item as a cooperative game where agents cooperate to form a surplus maximizing procurement network and then share the surplus in a fair manner. We study the implications of using the Shapley value as a solution concept for forming such procurement networks. We also present a protocol, based on the extensive form game realization of the Shapley value, for forming these networks.
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Detection of trace amounts of explosive materials is significantly important for security concerns and pollution control. Four multicomponent metal organic frameworks (MOFs-12, 13, 23, and 123) have been synthesized by employing ligands embedded with fluorescent tags. The multicomponent assembly of the ligands was utilized to acquire a diverse electronic behavior of the MOFs and the fluorescent tags were strategically chosen to enhance the electron density in the MOFs. The phase purity of the MOFs was established by PXRD, NMR spectroscopy, and finally by singlecrystal XRD. Single-crystal structures of the MOFs-12 and 13 showed the formation of three-dimensional porous networks with the aromatic tags projecting inwardly into the pores. These electron-rich MOFs were utilized for detection of ex- plosive nitroaromatic compounds (NACs) through fluorescence quenching with high selectivity and sensitivity. The rate of fluorescence quenching for all the MOFs follows the order of electron deficiency of the NACs. We also showed the detection of picric acid (PA) by luminescent MOFs is not always reliable and can be misleading. This attracts our attention to explore these MOFs for sensing picryl chloride (PC), which is as explosive as picric acid and used widely to prepare more stable explosives like 2,4,6-trinitroaniline from PA. Moreover, the recyclability and sensitivity studies indicated that these MOFs can be reused several times with parts per billion (ppb) levels of sensitivity towards PC and 2,4,6-trinitrotoluene (TNT).
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Hexagonal wireless sensor network refers to a network topology where a subset of nodes have six peer neighbors. These nodes form a backbone for multi-hop communications. In a previous work, we proposed the use of hexagonal topology in wireless sensor networks and discussed its properties in relation to real-time (bounded latency) multi-hop communications in large-scale deployments. In that work, we did not consider the problem of hexagonal topology formation in practice - which is the subject of this research. In this paper, we present a decentralized algorithm that forms the hexagonal topology backbone in an arbitrary but sufficiently dense network deployment. We implemented a prototype of our algorithm in NesC for TinyOS based platforms. We present data from field tests of our implementation, collected using a deployment of fifty wireless sensor nodes.
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Objectives: the purpose of this study is to employ optical microscopy to measure the thickness of the hybrid layer and the penetration (tags) of an aggressive self-etching adhesive system into sound dentin.Methods: occtusat cavities were prepared in 40 extracted human posterior teeth. The prepared teeth were randomly assigned to four experimental groups with 10 specimens each. The self-etching adhesive system Adper Prompt L-Pop was applied to the dentin surface as follows: Group 1: cavosurface enamel was etched for 60 s and dentin for 20 s with 35% phosphoric acid get, immediately followed by application of the self -etching adhesive with a brush to the entire cavity for 15 s; Groups 2, 3, and 4: no pre-etching was performed, and the self -etching adhesive was applied to both enamel and dentin for 15, 30 and 45 s, respectively. After curing, the cavities were fitted with composite resin Fittek Z250. Afterwards, the teeth were decalcified and the restorations were carefully removed for later embedding in paraffin. The specimens were serially sectioned at 6 mu m of thickness and sequentially mounted in glass slides. These sections were stained with Brown and Brenn staining for posterior analysis and measurement of the hybrid layer and resin tags on a tight microscope with a micrometric ocular 40/075. The results were submitted to analysis of variance at the 5% level.Results: whenever there was significance, the Tukey test was applied at the 5% level. The specimens receiving application of acid etching before the selfetching. adhesive displayed a larger thickness of the hybrid layer; on the other hand, specimens receiving only application of the self -etching adhesive on dentin for 15, 30 and 45 s exhibited similar thickness of the hybrid layer. As regards the resin tags, no statistically significant differences could be found between the study groups.Conclusions: it could be concluded that the increase in the time of application of the self-etching adhesive Adper Prompt L-Pop did not significantly influence the formation and thickness of hybrid layer, as well as its penetration into the sound dentin surface. (c) 2005 Elsevier Ltd. All rights reserved.
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Salpetrige Säure (HONO) ist eine wichtige Form von reaktivem Stickstoff, die aufgrund ihrer Photolyse zu Stickstoffmonoxid (NO) und dem Hydroxylradikal (OH), sehr kurzlebig ist. Ein genaues Verständnis der Quellen und Senken von HONO ist eine grundlegende Voraussetzung, um dessen Einfluss auf die Umwelt zu beurteilen. Allerdings wird immer noch nach einer starken HONO-Quelle am Tag gesucht und nächtliche HONO-Deposition auf den Boden wurde bisher stets nur postuliert. Diese Dissertation folgt der Zielsetzung die Prozesse der HONO-Aufnahme und Freisetzung von Böden aufzudecken und die zugrunde liegenden Mechanismen zu verstehen.rnUm die Rolle von HONO-Bodenemissionen zu quantifizieren, wurden 17 Böden in einem dynamischen Kammersystem untersucht. Es konnten HONO-Emissionen derselben Größenordnung wie die bereits gut untersuchten NO-Emissionen festgestellt werden. Unerwarteter Weise wurden die stärksten Emissionen bei Böden mit neutralem pH aus ariden und landwirt¬schaftlichen Gebieten beobachtet. Die Temperaturabhängigkeit der Bodenemissionen von HONO und NO führten zu der Annahme einer mikrobiellen Freisetzung von HONO, welche durch Reinkulturexperimente mit dem ammoniumoxidierenden Bakterium Nitrosomonas europaea bestätigt werden konnte. Ein konzeptionelles Model für die Freisetzung reaktiver Stickstoffverbindungen aus Böden in Abhängigkeit des Bodenwassergehaltes wurde um HONO-Emissionen erweitert.rnDurch Nachweise mittels Reinkultur- und Inhibitionsexperimenten konnten weitere Untersuchungen der bakteriellen Freisetzung von HONO aus Böden zeigen, dass innerhalb der bakteriellen Nitrifikation nur ammoniumoxidierende Bakterien zur Emission von HONO fähig sind. Durch kontrolliert initiierte Zelllyse konnte gezeigt werden, dass intrazellulär akkumuliertes Hydroxylamin (NH2OH) für die HONO-Freisetzung verantwortlich sind. Zum ersten Mal wurde NH2OH in der Gasphase nachgewiesen und dass dieses über den gesamten Bodenfeuchtebereich von ammoniumoxidierenden Bakterien freigesetzt wird. Es wurde gezeigt, dass die heterogene Reaktion von NH2OH mit Wasserdampf auf einer Glasperlenoberfläche HONO bildet. Diese Reaktion erklärt die beobachtete Freisetzung von HONO bei niedrigen Bodenfeuchten, da nur dann die Oberfläche zur Reaktion zur Verfügung steht und nicht von Wasser bedeckt ist.rnEine 15N Isotopenmarkierungsmethode wurde entwickelt um isotopenmarkiertes gasförmiges HONO zu messen, was die Untersuchung der Bildungsprozesse von HONO und dessen Rolle in biogeochemischen Zyklen ermöglicht. Die Anwendung dieser neuen Methode auf eine Bodenprobe die mit 15N Harnstoff angereichert und in einem dynamischen Kammersystem untersucht wurde, bestätigt die obigen Ergebnisse einer starken mikrobiellen Beteiligung von Bodenbakterien zur HONO Freisetzung.rnBidirektionale Flüsse von HONO wurden für sechs untersuchte Bodenproben gefunden. Die Richtung der Flüsse hängt dabei vom Umgebungsmischungsverhältnis von HONO und dem Bodenwassergehalt ab. Eine wichtige Größe, die die bidirektionalen Flüsse von HONO beschreibt, ist das „Ökosystem spezifische Kompensationsmischungsverhältnis von HONO“, χcomp. Dieser neue Begriff wurde definiert und eingeführt, da die verschiedenen in den Bodenaustausch von HONO involvierten Prozesse nicht mit dem klassischen Kompensationspunktkonzept kompatibel sind. Die Untersuchungen bestätigen neueste Feldbeobachtungen, dass HONO, welches bei hohen Umgebungsmischungsverhältnissen vom Boden adsorbiert wird, bei niedrigen Mischungsverhält-nissen wieder vom Boden desorbiert wird. Folglich wird nächtlich akkumuliertes HONO tagsüber in eine Quelle für HONO umgewandelt. Vier Prozesse - Verteilung von HONO zwischen Gas- und Flüssigphase nach Henrys Gesetz, bakterielle HONO Bildung aus NH2OH, Adsorption und Desorption von HONO - und deren Dominanz in speziellen Bodenfeuchtebereichen wurden identifiziert. Dadurch wurde ein konzeptionelles Model für die Prozesse, die in Aufnahme und Freisetzung von HONO aus Böden involviert sind, als Funktion der Bodenfeuchte entwickelt.rnZusammenfassend hat diese Dissertation die entscheidenden Prozesse im Austausch von HONO zwischen Boden und Atmosphäre aufgeklärt und den der bakteriellen HONO Bildung zugrunde liegenden Mechanismus aufgedeckt. Es konnte gezeigt werden, dass Böden sowohl eine wichtige Quelle als auch eine Senke für HONO sind und sollten folglich in zukünftigen Feldmessungen stärker berücksichtigt werden.rn