968 resultados para Hydrostatic bearing


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We report the genome sequence of Thermococcus superprofundus strain CDGST, a new piezophilic and hyperthermophilic member of the order Thermococcales isolated from the world’s deepest hydrothermal vents, at the Mid-Cayman Rise. The genome is consistent with a heterotrophic, anaerobic, and piezophilic lifestyle.

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Although the primary objective on designing a structure is to support the external loads, the achievement of an optimal layout that reduces all costs associated with the structure is an aspect of increasing interest. The problem of finding the optimal layout for bridgelike structures subjected to a uniform load is considered. The problem is formulated following a theory on economy of frame structures, using the stress volume as the objective function and including the selection of appropriate values for statically indeterminate reactions. It is solved in a function space of finite dimension instead of using a general variational approach, obtaining near-optimal solutions. The results obtained with this profitable strategy are very close to the best layouts known to date, with differences of less than 2% for the stress volume, but with a simpler layout that can be recognized in some real bridges. This strategy could be a guide to preliminary design of bridges subject to a wide class of costs.

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Purpose: To evaluate the antitumor activity of doxorubicine (DOX)-loaded nanoemulsion (NE) on Ehrlich ascites carcinoma (EAC)-bearing Swiss albino mice. Methods: The mice were divided into five groups (n = 20) according to the administered drug. Groups I - V were labeled as negative control (normal), positive control of the untreated EAC bearing mice (EAC control), blank nanoemulsion (BI-NE), DOX-loaded-NE (DOX/LNE) and free DOX (DOX-Sol), respectively. Cardiotoxicity was assessed by measuring changes in body and organ weight, analyzing serum enzymes and lipids, and examining histological changes in heart tissues by light microscopy. In addition, mean survival time (MST), increase in life span (ILS) and survival (S) of the mice were determined. Results: DOX/LNE group reduced levels of serum enzymes and lowered damage to heart tissues relative to DOX-Sol group. The MST of the DOX/LNE group (80 ± 0.0 days) was significantly greater than that for DOX-Sol group (34.6 ± 8.9 days), while ILS of DOX/LNE (265.30 days) was higher than that of DOX-Sol (57.99 days) by 4.6-fold. Conclusion: Administration of DOX/LNE to EAC-bearing mice improves the efficacy of DOX and reduce its side effects on the heart.

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This paper questions the current concept of quality as used in research assessment rankings and peer review, with special reference to the link often established between impact and the way this impact is measured in the form of citation counting. Taking translation studies as a case study, we will offer a two-level approach to reveal both the macro- and micro-level biases that exist in this regard. We will first review three key aspects related to the idea of the quality of publications, namely peer review, journal indexing, and journal impact factor. We will then pinpoint some of the main macro-level problems regarding current practices and criteria as applied to translation studies, such as Thomson Reuters World of Science's journal coverage, citation patterns, and publication format. Next we will provide a micro-textual and practical perspective, focusing on citation counts and suggesting a series of corrective measures to increase comparability.

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Seven Klebsiella pneumoniae isolates from dogs and cats in Spain were found to be highly resistant to aminoglycosides, and ArmA methyltransferase was responsible for this phenotype. All isolates were typed by multilocus sequence typing (MLST) as ST11, a human epidemic clone reported worldwide and associated with, among others, OXA-48 and NDM carbapenemases. In the seven strains, armA was borne by an IncR plasmid, pB1025, of 50 kb. The isolates were found to coproduce DHA-1 and SHV-11 β-lactamases, as well as the QnrB4 resistance determinant. This first report of the ArmA methyltransferase in pets illustrates their importance as a reservoir for human multidrug-resistant K. pneumoniae.

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TEM-1 is the dominant β-lactamase of Haemophilus influenzae and can be located on small plasmids. Three distinct plasmids with sizes from 4,304 to 5,646 nucleotides (nt) were characterized: pA1606, pA1209, and pPN223. In addition to TEM-1 and a replication enzyme of the Rep 3 superfamily, pA1606 carries a Tn3 resolvase gene and pA1606 and pA1209 carry an open reading frame (ORF) similar to a plasmid recombination enzyme gene described in Gram-positive bacteria. The plasmids transformed strain Rd to the ampicillin-resistant phenotype.

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Plasmid pB1000 is a mobilizable replicon bearing the bla(ROB-1) beta-lactamase gene that we have recently described in Haemophilus parasuis and Pasteurella multocida animal isolates. Here we report the presence of pB1000 and a derivative plasmid, pB1000', in four Haemophilus influenzae clinical isolates of human origin. Pulsed-field gel electrophoresis showed unrelated patterns in all strains, indicating that the existence of pB1000 in H. influenzae isolates is not the consequence of clonal dissemination. The replicon can be transferred both by transformation and by conjugation into H. influenzae, giving rise to recipients resistant to ampicillin and cefaclor (MICs, > or =64 microg/ml). Stability experiments showed that pB1000 is stable in H. influenzae without antimicrobial pressure for at least 60 generations. Competition experiments between isogenic H. influenzae strains with and without pB1000 revealed a competitive disadvantage of 9% per 10 generations for the transformant versus the recipient. The complete nucleotide sequences of nine pB1000 plasmids from human and animal isolates, as well as the epidemiological data, suggest that animal isolates belonging to the Pasteurellaceae act as an antimicrobial resistance reservoir for H. influenzae. Further, since P. multocida is the only member of this family that can colonize both humans and animals, we propose that P. multocida is the vehicle for the transport of pB1000 between animal- and human-adapted members of the Pasteurellaceae.

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Haemophilus parasuis, the causative agent of Glässer's disease, is one of the early colonizers of the nasal mucosa of piglets. It is prevalent in swine herds, and lesions associated with disease are fibrinous polyserositis and bronchopneumonia. Antibiotics are commonly used in disease control, and resistance to several antibiotics has been described in H. parasuis. Prediction of H. parasuis virulence is currently limited by our scarce understanding of its pathogenicity. Some genes have been associated with H. parasuis virulence, such as lsgB and group 1 vtaA, while biofilm growth has been associated with nonvirulent strains. In this study, 86 H. parasuis nasal isolates from farms that had not had a case of disease for more than 10 years were obtained by sampling piglets at weaning. Isolates were studied by enterobacterial repetitive intergenic consensus PCR and determination of the presence of lsgB and group 1 vtaA, biofilm formation, inflammatory cell response, and resistance to antibiotics. As part of the diversity encountered, a novel 2,661-bp plasmid, named pJMA-1, bearing the blaROB-1 β-lactamase was detected in eight colonizing strains. pJMA-1 was shown to share a backbone with other small plasmids described in the Pasteurellaceae, to be 100% stable, and to have a lower biological cost than the previously described plasmid pB1000. pJMA-1 was also found in nine H. parasuis nasal strains from a separate collection, but it was not detected in isolates from the lesions of animals with Glässer's disease or in nontypeable Haemophilus influenzae isolates. Altogether, we show that commensal H. parasuis isolates represent a reservoir of β-lactam resistance genes which can be transferred to pathogens or other bacteria.

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Axle bearing damage with possible catastrophic failures can cause severe disruptions or even dangerous derailments, potentially causing loss of human life and leading to significant costs for railway infrastructure managers and rolling stock operators. Consequently the axle bearing damage process has safety and economic implications on the exploitation of railways systems. Therefore it has been the object of intense attention by railway authorities as proved by the selection of this topic by the European Commission in calls for research proposals. The MAXBE Project (http://www.maxbeproject.eu/), an EU-funded project, appears in this context and its main goal is to develop and to demonstrate innovative and efficient technologies which can be used for the onboard and wayside condition monitoring of axle bearings. The MAXBE (interoperable monitoring, diagnosis and maintenance strategies for axle bearings) project focuses on detecting axle bearing failure modes at an early stage by combining new and existing monitoring techniques and on characterizing the axle bearing degradation process. The consortium for the MAXBE project comprises 18 partners from 8 member states, representing operators, railway administrations, axle bearing manufactures, key players in the railway community and experts in the field of monitoring, maintenance and rolling stock. The University of Porto is coordinating this research project that kicked-off in November 2012 and it is completed on October 2015. Both on-board and wayside systems are explored in the project since there is a need for defining the requirement for the onboard equipment and the range of working temperatures of the axle bearing for the wayside systems. The developed monitoring systems consider strain gauges, high frequency accelerometers, temperature sensors and acoustic emission. To get a robust technology to support the decision making of the responsible stakeholders synchronized measurements from onboard and wayside monitoring systems are integrated into a platform. Also extensive laboratory tests were performed to correlate the in situ measurements to the status of the axle bearing life. With the MAXBE project concept it will be possible: to contribute to detect at an early stage axle bearing failures; to create conditions for the operational and technical integration of axle bearing monitoring and maintenance in different European railway networks; to contribute to the standardization of the requirements for the axle bearing monitoring, diagnosis and maintenance. Demonstration of the developed condition monitoring systems was performed in Portugal in the Northern Railway Line with freight and passenger traffic with a maximum speed of 220 km/h, in Belgium in a tram line and in the UK. Still within the project, a tool for optimal maintenance scheduling and a smart diagnostic tool were developed. This paper presents a synthesis of the most relevant results attained in the project. The successful of the project and the developed solutions have positive impact on the reliability, availability, maintainability and safety of rolling stock and infrastructure with main focus on the axle bearing health.

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This paper presents the conception of an original superconducting Frictionless Zero Field Cooling bearing virtual prototype. In previous work also shown in this conference, a viability study of a Zero Field Cooling-superconducting bearing concept was conducted. It showed that the virtual prototype is feasible. Moreover, the simulation studies showed that a Zero Field Cooling superconducting track provides not only effective lateral stability but also higher levitation forces than the commonly used Field Cooling tracks. In this paper the new Zero Field Cooling -bearing virtual prototype is modeled in 3D. The virtual prototype was designed having in mind: i) a future implementation in high density polyurethane, for low temperature robustness; ii) future manufacturing in a three axes CNC milling machine and; iii) future implementation of some parts using an additive manufacturing technique.

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Convergent plate boundaries are sites of sustained chemical exchanges between the Earth’s surface and deep geochemical reservoirs, playing a major role in the global cycle of carbon and sulfur. However, carbon and sulfur recycling processes continue to be hotly debated. A critical gap in the knowledge of the whole subduction factory is given by the limited accessibility to the upper mantle residing above the subducting plate, the so-called mantle wedge. This thesis investigates the carbonate and sulfide metasomatism taking place during the whole metamorphic evolution of a mantle wedge involved in the Variscan continental collision. We integrate different detailed geochemical and petrological techniques to orogenic carbonated spinel and garnet peridotites from the Ulten Zone of the Eastern Italian Alps. Our data show that the Ulten Zone peridotite experienced multiple stages of addition and removal of carbon and sulfur throughout its metamorphic evolution, as follows: (1) The Variscan lithospheric mantle was initially depleted and sulfide-poor. It subsequently inherited a sulfur and carbon component during an early metasomatic stage, when hot, H2S-CO2-bearing melts leaving a subduction-modified source percolated the overlying spinel-facies peridotite in the mantle wedge; (2) Under peak eclogite-facies P-T conditions, pervasive carbonation and sulfidation occurred. Heterogeneous melt and fluid sources variably enriched in carbon, isotopically heavy sulfur and radiogenic Sr were involved; (3) Shortly after the attainment of peak-P conditions, peridotite bodies were incorporated in a tectonic mélange with the neighboring gneisses. Here, the Ulten Zone peridotite was exposed to channelized infiltration of hybridized C-O-H fluids that promoted the formation of veinlets of carbonates locally associated with sulfide grains. (4) Upon late retrogression, infiltration of serpentinizing fluids promoted C and S remobilization at shallow crustal levels.

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Recently, Physalaemus albifrons (Spix, 1824) was relocated from the Physalaemus cuvieri group to the same group as Physalaemus biligonigerus (Cope, 1861), Physalaemus marmoratus (Reinhardt & Lütken, 1862) and Physalaemus santafecinus Barrio, 1965. To contribute to the analysis of this proposition, we studied the karyotypes of Physalaemus albifrons, Physalaemus santafecinus and three species of the Physalaemus cuvieri group. The karyotype of Physalaemus santafecinus was found to be very similar to those of Physalaemus biligonigerus and Physalaemus marmoratus, which were previously described. A remarkable characteristic that these three species share is a conspicuous C-band that extends from the pericentromeric region almost to the telomere in the short arm of chromosome 3. This characteristic is not present in the Physalaemus albifrons karyotype and could be a synapomorphy of Physalaemus biligonigerus, Physalaemus marmoratus and Physalaemus santafecinus. The karyotype of Physalaemus santafecinus is also similar to those of Physalaemus marmoratus and Physalaemus biligonigerus owing to the presence of several terminal C-bands and the distal localization of the NOR in a small metacentric chromosome. In contrast, the Physalaemus albifrons karyotype has no terminal C-bands and its NOR is located interstitially in the long arm of submetacentric chromosome 8. The NOR-bearing chromosome of Physalaemus albifrons very closely resembles those found in Physalaemus albonotatus (Steindachner, 1864), Physalaemus cuqui Lobo, 1993 and some populations of Physalaemus cuvieri Fitzinger, 1826. Additionally, the Physalaemus albifrons karyotype has an interstitial C-band in chromosome 5 that has been exclusively observed in species of the Physalaemus cuvieri group. Therefore, we were not able to identify any chromosomal feature that supports the reallocation of Physalaemus albifrons.

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Cardiac arrest after open surgery has an incidence of approximately 3%, of which more than 50% of the cases are due to ventricular fibrillation. Electrical defibrillation is the most effective therapy for terminating cardiac arrhythmias associated with unstable hemodynamics. The excitation threshold of myocardial microstructures is lower when external electrical fields are applied in the longitudinal direction with respect to the major axis of cells. However, in the heart, cell bundles are disposed in several directions. Improved myocardial excitation and defibrillation have been achieved by applying shocks in multiple directions via intracardiac leads, but the results are controversial when the electrodes are not located within the cardiac chambers. This study was designed to test whether rapidly switching shock delivery in 3 directions could increase the efficiency of direct defibrillation. A multidirectional defibrillator and paddles bearing 3 electrodes each were developed and used in vivo for the reversal of electrically induced ventricular fibrillation in an anesthetized open-chest swine model. Direct defibrillation was performed by unidirectional and multidirectional shocks applied in an alternating fashion. Survival analysis was used to estimate the relationship between the probability of defibrillation and the shock energy. Compared with shock delivery in a single direction in the same animal population, the shock energy required for multidirectional defibrillation was 20% to 30% lower (P < .05) within a wide range of success probabilities. Rapidly switching multidirectional shock delivery required lower shock energy for ventricular fibrillation termination and may be a safer alternative for restoring cardiac sinus rhythm.

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A versatile and metal-free approach for the synthesis of carbocycles and of heterocycles bearing seven- and eight-membered rings is described. The strategy is based on ring expansion of 1-vinylcycloalkanols (or the corresponding silyl or methyl ether) mediated by the hypervalent iodine reagent HTIB (PhI(OH)OTs). Reaction conditions can be easily adjusted to give ring expansion products bearing different functional groups. A route to medium-ring lactones was also developed.

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Placental tissue injury is concomitant with tumor development. We investigated tumor-driven placental damage by tracing certain steps of the protein synthesis and degradation pathways under leucine-rich diet supplementation in MAC16 tumor-bearing mice. Cell signaling and ubiquitin-proteasome pathways were assessed in the placental tissues of pregnant mice, which were distributed into three groups on a control diet (pregnant control, tumor-bearing pregnant, and pregnant injected with MAC-ascitic fluid) and three other groups on a leucine-rich diet (pregnant, tumor-bearing pregnant, and pregnant injected with MAC-ascitic fluid). MAC tumor growth down-regulated the cell-signaling pathways of the placental tissue and decreased the levels of IRS-1, Akt/PKB, Erk/MAPK, mTOR, p70S6K, STAT3, and STAT6 phosphorylated proteins, as assessed by the multiplex Millipore Luminex assay. Leucine supplementation maintained the levels of these proteins within the established cell-signaling pathways. In the tumor-bearing group (MAC) only, the placental tissue showed increased PC5 mRNA expression, as assessed by quantitative RT-PCR, decreased 19S and 20S protein expression, as assessed by Western blot analysis, and decreased placental tyrosine levels, likely reflecting up-regulation of the ubiquitin-proteasome pathway. Similar effects were found in the pregnant injected with MAC-ascitic fluid group, confirming that the effects of the tumor were mimicked by MAC-ascitic fluid injection. Although tumor progression occurred, the degradation pathway-related protein levels were modulated under leucine-supplementation conditions. In conclusion, tumor evolution reduced the protein expression of the cell-signaling pathway associated with elevated protein degradation, thereby jeopardizing placental activity. Under the leucine-rich diet, the impact of cancer on placental function could be minimized by improving the cell-signaling activity and reducing the proteolytic process.