977 resultados para part pure bending


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The potential therapeutic value of cell-based therapy with mesenchymal stem cells (MSC) has been reported in mouse models of polymicrobial peritoneal sepsis. However, the mechanisms responsible for the beneficial effects of MSC have not been well defined. Therefore, we tested the therapeutic effect of intravenous bone marrow-derived human MSC in peritoneal sepsis induced by gram-negative bacteria. At 48 h, survival was significantly increased in mice treated with intravenous MSC compared with control mice treated with intravenous fibroblasts (3T3) or intravenous PBS. There were no significant differences in the levels of TNF-a, macrophage inflammatory protein 2, or IL-10 in the plasma. However, there was a marked reduction in the number of bacterial colony-forming units of Pseudomonas aeruginosa in the blood of MSC-treated mice compared with the 3T3 and PBS control groups. In addition, phagocytic activity was increased in blood monocytes isolated from mice treated with MSC compared with the 3T3 and PBS groups. Furthermore, levels of C5a anaphylotoxin were elevated in the blood of mice treated with MSC, a finding that was associated with upregulation of the phagocytosis receptor CD11b on monocytes. The phagocytic activity of neutrophils was not different among the groups. There was also an increase in alternately activated monocytes/macrophages (CD163- and CD206-positive) in the spleen of the MSC-treated mice compared with the two controls. Thus intravenous MSC increased survival from gram-negative peritoneal sepsis, in part by a monocyte-dependent increase in bacterial phagocytosis.

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Recent in vivo studies indicate that mesenchymal stem cells (MSCs) may have beneficial effects in the treatment of sepsis induced by bacterial infection. Administration of MSCs in these studies improved survival and enhanced bacterial clearance. The primary objective of this study was to test the hypothesis that human MSCs possessed intrinsic antimicrobial properties. We studied the effect of human MSCs derived from bone marrow on the bacterial growth of Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. MSCs as well as their conditioned medium (CM) demonstrated marked inhibition of bacterial growth in comparison with control medium or normal human lung fibroblasts (NHLF). Analysis of expression of major antimicrobial peptides indicated that one of the factors responsible for the antimicrobial activity of MSC CM against Gram-negative bacteria was the human cathelicidin antimicrobial peptide, hCAP-18/LL-37. Both m-RNA and protein expression data showed that the expression of LL-37 in MSCs increased after bacterial challenge. Using an in vivo mouse model of E. coli pneumonia, intratracheal administration of MSCs reduced bacterial growth (in colony-forming unit) in the lung homogenates and in the bronchoalveolar lavage (BAL) fluid, and administration of MSCs simultaneously with a neutralizing antibody to LL-37 resulted in a decrease in bacterial clearance. In addition, the BAL itself from MSC-treated mice had a greater antimicrobial activity in comparison with the BAL of phosphate buffered saline (PBS)-treated mice. Human bone marrow-derived MSCs possess direct antimicrobial activity, which is mediated in part by the secretion of human cathelicidin hCAP-18/ LL-37.

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The aim of this paper was to define the outcomes and risks of stereotactic radiosurgery (SRS) for Spetzler-Martin Grade I and II arteriovenous malformations (AVMs).

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The authors conducted a study to define the long-term outcomes and risks of stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) of the basal ganglia and thalamus.

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In this paper, the authors' goal was to define the long-term outcomes and risks of stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) of the medulla, pons, and midbrain.

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The aims of this article are to examine Lifetime Home Standards (LTHS) and Part M of the UK Building Regulations and to discuss how relevant and successful they are. The UK government expects all new homes to be built to LTHS by 2013. This is increasingly important with an ageing population. The home environment can enable independence and provide a therapeutic place for everyone. As Part M of the building regulations are compulsory in all housing and LTHS are mandatory for public sector housing, a review of research articles was undertaken on these standards. The paper begins with a brief background on accessibility regulations, followed by a critical review of the standards that takes the body of literature that has been written around them into account. This review suggests that the standards should be improved and that designers and architects face challenges to creatively incorporate them into housing design.

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This exhibition profiles the curatorial approach of PS² and the work of creative practitioners who have practiced alongside and with the organisation. PS² is a Belfast-based, voluntary arts organisation that initiates projects inside and outside its project space. It seeks to develop a socio-spatial practice that responds to the post-conflict context of Northern Ireland, with particular focus on active intervention and social interaction between local people, creative practitioners, multidisciplinary groups and theorists.
Morrow has collaborated with PS² since its inception in 2005, acting as curatorial advisor specifically on the projects that occur outside PS² . She regards her involvement as a parallel action to her pedagogical explorations within architectural education.

Morrow's personal contribution to the Exhibition aimed to:
-interrogate PS² spatial projects
-contextualise PS² curatorial practice
-open up the analytical framework and extend to similar local practices

The Shed, Galway, Ireland is a joint Galway City Arts and Harbour Company venture. The exhibition subsequently travelled to DarcSpace Gallery, Dublin (Sept 2013).

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The unsteady gas dynamic phenomena in a racecar airbox have been examined, and resonant tuning effects have been considered. A coupled 1D/3D analysis, using the engine simulation package Virtual 4-Stroke and the CFD package FLUENT, was used to model the engine and airbox. The models were experimentally validated. An airbox was designed with a natural frequency in the region of 75 Hz. A coupled 1D/3D analysis of the airbox and a Yamaha R6 4 cylinder engine predicted resonance at the single-cylinder induction frequency; 75 Hz at an engine speed of 9000 rpm.

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Steady simulations were performed to investigate tip leakage flow and heat transfer characteristics on the rotor blade tip and casing in a single-stage gas turbine engine. A typical high-pressure gas turbine stage was modeled with a pressure ratio of 3.2. The predicted isentropic Mach number and adiabatic wall temperature on the casing showed good agreement with available experimental data under similar operating condition. The present numerical study focuses extensively on the effects of tip clearance heights and rotor rotational speeds on the blade tip and casing heat transfer characteristics. It was observed that the tip leakage flow structure is highly dependent on the height of the tip gap and the speed of the rotor. In all cases, the tip leakage flow was seen to separate and recirculate just around the corner of the pressure side of the blade tip. This region of re-circulating flow enlarges with increasing clearance heights. The separated leakage flow reattaches afterwards on the tip surface. Leakage flow reattachment was shown to enhance surface heat transfer at the tip. The interaction between tip leakage flow and secondary flows that is induced by the relative casing motion is found to significantly influence the blade tip and casing heat transfer distribution. A region of critical heat transfer exists on the casing near the blade tip leading edge and along the pressure-side edge for all the clearance heights that were investigated. At high rotation speed, the region of critical heat transfer tends to move towards the trailing edge due to the change in inflow angle.

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The commercial production of vanillin from sodium lignosulfonate under highly alkaline conditions, catalyzed by Cu2+ at elevated temperature and pressures up to 10 bar, has been simulated in a 3-L stirred reactor. Initially, the process was operated in the presence of nitrogen in dead-end mode, and it was shown that vanillin and vanillic acid were formed by hydrolysis at temperatures of 120, 140, and 160 °C. At the two higher temperatures, the amount of vanillin produced was the same. Subsequently, experiments were conducted at the same elevated pressures and temperatures with addition of air or oxygen-enriched air once the temperature in the reactor had reached temperatures similar to those used when only hydrolysis occurred. In this case, the concentration of vanillin at 140 and 160 °C was equal to that due to hydrolysis, and the subsequent 2-fold increase was due to oxidation. In addition, both vanillic acid and acetovanillone (which has rarely been reported) were produced, as was hydrogen. Thus, for the first time, it has been shown that the production of vanillin (and other compounds) from sodium lignosulfonate at elevated temperatures involves hydrolysis and oxidation, with hydrolysis starting at just above 100 °C, that is, much lower than has previously been reported. Approximately 50% is produced by each mechanism. In addition, the orders of the reactions of the different steps were estimated, and the reaction mechanisms are discussed.

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NiTi wires and their weldments are commonly used in micro-electro-mechanical systems (MEMS), and in such applications, cyclic loading are commonly encountered. In this paper, the bending-rotation fatigue (BRF) test was used to study the bending fatigue behavior of NiTi wire laser weldment in the small-strain regime. The fracture mechanism, which includes crack initiation, crack growth and propagation of the weldment in the BRF test, was investigated with the aid of SEM fractography and discussed in terms of the microstructure. It was found that crack initiation was primarily surface-condition dependent. The cracks were found to initiate at the surface defects at the weld zone (WZ) surface, and the crack propagation was assisted by the gas inclusions in the WZ. The weldment was finally fractured in a ductile manner. The fatigue life was found to decrease with increasing surface strain and also with increasing bending frequency (controlled by the rotational speed in the BRF test). In comparison, the fatigue life of the unwelded NiTi wires was higher than their welded counterparts at all strain levels and bending frequencies. The decrease in fatigue resistance of the weldment could be attributed to the surface and microstructural defects introduced during laser welding.

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Hydrodynamic models are a powerful tool that can be used by a wide range of end users to assist in predicting the effects of both physical and biological processes on local environmental conditions. This paper describes the development of a tidal model for Strangford Lough, Northern Ireland, a body of water renowned for the location of the first grid-connected tidal turbine, SeaGen, as well as the UK’s third Marine Nature Reserve. Using MIKE 21 modelling software, the development, calibration and performance of the modelare described in detail. Strangford Lough has a complex flow pattern with high flows through the Narrows (~3.5 m/s) linking the main body of the Lough to the Irish Sea and intricate flow patterns around the numerous islands. With the aid of good quality tidal and current data obtained throughout the Lough during the model development, the surface elevation and current magnitude between the observed and numerical model were almost identical with model skill >0.98 and >0.84 respectively. The applicability of the model is such that it can be used as an important tool for the prediction of important ecological processes as well as engineering applications within Strangford Lough.