114 research outputs found
The impact of the steel cord construction on its decline of breaking force after fatigue test in bidirectional bending conditions
In the paper the influence of bidirectional bending on breaking force of steel cord has been assessed. Tests were carried out under laboratory conditions on three types of cord. It was found that bidirectional bending of steel cord cause the deterioration of strength properties and weakening of steel cord as a result of its fatigue. The obtained results may find application in the wire industry while implementing the new production technologies of steel cord
The mechanical properties of high carbon steel wires drawn in conventional and hydrodynamic dies
In the paper the influence of the hydrodynamic die on mechanical properties has been assessed. The drawing process of Ï 5,5 mm wires to the final wire of Ï 2,5 mm was conducted in 7 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speed in the last passes was 8,2 m/s. On the basis of numerical analyses wire drawing process, the redundant strain of wires has been determined. In the case of the wires drawn with hydrodynamic dies the increase of plasticity properties have been noted. It has been shown that the increase of strength properties in wires drawn with conventional die is related to the occurrence in their bigger redundant strain
The effect of multiple bending of wire on the residual stresses of high carbon steel wires
Steel tire cord, springs and rope wires belong to the group of metal products from which the low residual stresses are required. In this paper the effect of multiple bending of wire on residual stresses of high carbon steel wires has been assessed. It was found that the application of the multi-roller straightening machine in the banding wire process enables to reduce the residual stresses in the drawn wires. It should be also noted that the value of the residual stresses depends on the type of straightener construction. The residual stresses on the basis of stress-strain curve has been determined. It has been stated that the application of seven-rolls straightener gives the best effect of straightening
The influence of drawing speed on structure changes in high carbon steel wires
In the paper the influence of the drawing speed on structure changes has been assessed. The Scanning Electron Microscope investigation confirmed that for wires drawn with high total draft, exceeding 80 %, makes it impossible to clearly assess the impact of drawing technology on structural changes in the drawn wires. Thus, to assess the structural changes necessary to apply quantitative methods. On the basis of examination of the wire structure by measuring of electrical resistance, the structure changes in drawn wires has been determined. It has been shown that the increase of drawing speed, especially above 15 m/s, causes an increase in structure defect, with a decline in platelet orientation of cementite in drawn wires
Hyperammonemic ComaâBarking Up the Wrong Tree
Hepatic encephalopathy and myxedema coma share clinical features: coma, ascites, anemia, impaired liver functions, and a âmetabolicâ electroencephalogram (EEG). Hyperammonemia, a hallmark of hepatic encephalopathy, has also been described in hypothyroidism. Differentiation between the 2 conditions, recognition of their possible coexistence, and the consequent therapeutic implications are of utmost importance. We describe a case of an 82-year-old woman with a history of mild chronic liver disease who presented with hyperammonemic coma unresponsive to conventional therapy. Further investigation disclosed severe hypothyroidism. Thyroid hormone replacement resulted in gain of consciousness and normalization of hyperammonemia. In patients with an elevated ammonia level, altered mental status, and liver disease, who do not have a clear inciting event for liver disease decompensation, overwhelming evidence of hepatic decompensation, or who do not respond to appropriate therapy for hepatic encephalopathy, hypothyroidism should be considered and evaluated
Lactoferrin is a survival factor for neutrophils in rheumatoid synovial fluid
Objectives. Lactoferrin is an iron-binding protein that is released from activated neutrophils at sites of inflammation and has anti-microbial as well as anti-inflammatory properties. This study set out to determine whether lactoferrin can delay neutrophil apoptosis and could act as a survival factor for neutrophils in SF
Allelic Exchange of Pheromones and Their Receptors Reprograms Sexual Identity in Cryptococcus neoformans
Cell type specification is a fundamental process that all cells must carry out to ensure appropriate behaviors in response to environmental stimuli. In fungi, cell identity is critical for defining âsexesâ known as mating types and is controlled by components of mating type (MAT) loci. MATâencoded genes function to define sexes via two distinct paradigms: 1) by controlling transcription of components common to both sexes, or 2) by expressing specially encoded factors (pheromones and their receptors) that differ between mating types. The human fungal pathogen Cryptococcus neoformans has two mating types (a and α) that are specified by an extremely unusual MAT locus. The complex architecture of this locus makes it impossible to predict which paradigm governs mating type. To identify the mechanism by which the C. neoformans sexes are determined, we created strains in which the pheromone and pheromone receptor from one mating type (a) replaced the pheromone and pheromone receptor of the other (α). We discovered that these âαaâ cells effectively adopt a new mating type (that of a cells); they sense and respond to α factor, they elicit a mating response from α cells, and they fuse with α cells. In addition, αa cells lose the α cell type-specific response to pheromone and do not form germ tubes, instead remaining spherical like a cells. Finally, we discovered that exogenous expression of the diploid/dikaryon-specific transcription factor Sxi2a could then promote complete sexual development in crosses between α and αa strains. These data reveal that cell identity in C. neoformans is controlled fully by three kinds of MATâencoded proteins: pheromones, pheromone receptors, and homeodomain proteins. Our findings establish the mechanisms for maintenance of distinct cell types and subsequent developmental behaviors in this unusual human fungal pathogen
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The 'knowledge politics' of democratic peace theory
How do academic ideas influence US foreign policy, under what conditions and with what consequences? This article traces the rise, âsecuritisationâ and political consequences of democratic peace theory (DPT) in the United States by exploring the work of Doyle, Diamond and Fukuyama. Ideas influence US foreign policy under different circumstances, but are most likely to do either during and after crises when the policy environment permits ânew thinkingâ, or when these ideas have been developed through state-connected elite knowledge networks, or when they are (or appear paradigmatically congenial to) foreign policymakersâ mindsets, or, finally, when they become institutionally-embedded. The appropriation of DPT by foreign policymakers has categorised the world into antagonistic blocs â democratic/non-democratic zones of peace/turmoil â as the corollary to a renewed American mission to make the world âsaferâ through âdemocracyâ promotion. The roles of networked organic intellectuals â in universities and think tanks, for instance â were particularly important in elevating DPT from the academy to national security managers
Pectinas de plantas medicinais: caracterĂsticas estruturais e atividades imunomoduladoras
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