103 resultados para Valves.


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Infective endocarditis is a process in which an infection attacks the heart endothelial surface, and is commonly caused by bacterial colonization, which is called bacterial endocarditis. It is a condition rarely found in dogs and cats, and is more prevalent in male dogs of large size. It mainly affects the left side of the heart, affecting the mitral and aortic valves with greater frequency. The circulation of the bacterium in the bloodstream is what gives rise endocarditis, and is caused by any non-aseptic process that serves as a gateway for bacterium in the body, as from a skin lesion, even as an invasive procedure, such as, catheterization and surgery. The ante-mortem diagnosis is difficult because the clinical signs of endocarditis are varied and common to other diseases, summing up the signs of infection (fever, lethargy, weight loss), and presence of heart murmur and may show signs of congestive heart failure. Thus, the diagnosis is most often through autopsy. To arrive at a diagnosis should be used, besides the history and physical examination, some laboratory tests, especially blood cultures and echocardiography. Treatment is accomplished through the use of antibiotics for long period of time, it is very important to follow the results of susceptibility after its outcome is revealed. The prognosis for bacterial endocarditis ranges from guarded to poor, and can be assessed mainly by the echocardiography. There are few studies in veterinary about the bacterial endocarditis, and the majority is case reports

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pressure drop and energy efficiency of compressors in chemical plants are the focus of this study. Its objective is an analysis of possible sources of energy loss through the study of pressure loss in pipes, calculation of thermodynamic efficiency of the compressors. Important issues are raised for this analysis such as the types of compressors, the operating range of each compressor, compression types, as well as a study of accessories such as filters and valves. After studying these issues was carried out calculations of pressure drop step-bystep and with a software WIPCD. Followed by the calculation of efficiency of compressors and monthly energy cost of each compressor in operation. Finally, the study shows some suggestions for immediate improvements, changes and suggestions for possible future purchases of compressors

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This work studies the most commonly used methods and make comparisons and discussions of the findings made by each of them and the results provided by them. The objective of this research was to show that the method of characteristics is currently the most efficient method to perform these simulations because of its broad scope low simplifications, requirement allowing to consider every detail of the pipe and fluid. Manual calculations are performed and also a software capable of calculating this phenomenon for various situations, such as water pump, elevated tanks, valves and quick maneuver was developed. The software is based on the method of characteristics that is currently recommended by ABNT. These methods, and the results are obtained numerically and graphically are adopted pipes and amount of downstream conditions and in which will be applied. The conclusions reached showed that the Allievi method is widely used yet because of its efficiency and quick calculation for simple pipes. The method of characteristics, although a lot of work to be calculated due to the calculation is iterative process and requires a program to use it, is the only one that allows the calculation with all amount to the conditions situations and downstream of all the pipe possibilities found

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Calcific aortic valve disease (CAVD) is a chronic disorder characterized by an abnormal mineralization of the leaflets, which is accelerated in bicuspid aortic valve (BAV). It is suspected that mechanical strain may promote/enhance mineralization of the aortic valve. However, the effect of mechanical strain and the involved pathways during mineralization of the aortic valve remains largely unknown. Valve interstitial cells (VICs) were isolated and studied under strain conditions. Human bicuspid aortic valves were examined as a model relevant to increase mechanical strain. Cyclic strain increased mineralization of VICs by several-fold. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analyses revealed that mechanical strain promoted the formation of mineralized spheroid microparticles, which coalesced into larger structure at the surface of apoptotic VICs. Apoptosis and mineralization were closely associated with expression of ENPP1. Inhibition of ENPP1 greatly reduced mineralization of VIC cultures. Through several lines of evidence we showed that mechanical strain promoted the export of ENPP1-containing vesicles to the plasma membrane through a RhoA/ROCK pathway. Studies conducted in human BAV revealed the presence of spheroid mineralized structures along with the expression of ENPP1 in areas of high mechanical strain. Mechanical strain promotes the production and accumulation of spheroid mineralized microparticles by VICs, which may represent one important underlying mechanism involved in aortic valve mineralization. RhoA/ROCK-mediated export of ENPP1 to the plasma membrane promotes strain-induced mineralization of VICs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new species of Myxosporea, Henneguya aequidens sp. n. (Myxozoa: Myxobolidae), was described based on its ultrastructural features. This is a parasite of the freshwater fish Aequidens plagiozonatus, in the Peixe-boi River, Para, Brazil. This parasite was found in the gills, in the form of whitish ellipsoid cysts with mature spores inside them. The average spore body was 15 +/- 0.9 mu m in length (n = 30) and 6 +/- 0.8 mu m in width (n = 30), and the tail measured 27 +/- 0.5 mu m in length (n = 15). The spores showed typical features of the genus Henneguya with two valves of equal size and two symmetrical polar capsules of 3 +/- 0.3 mu m in length and 2 +/- 0.3 mu m in width. Each polar capsule had a polar filament forming a helix from the apical region to the polar caps, with four to six turns. Based on the ultrastructural differences in morphology of these spores, the location of the parasite, and its host specificity, this parasite was described as a new species.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In water distribution systems, old metallic pipes have been replaced by plastic pipes due to their deterioration over time. Although acoustic methods are effective in finding leaks in metallic pipes, they have been found to be problematic when applied to plastic pipes due to the high damping within the pipe wall and the surrounding medium. This is responsible for the leak signal not traveling long distances. Moreover, the leak energy in plastic pipes is generally located at a narrow frequency range located at low frequencies. However, the presence of resonances can narrow even more this frequency range. In order to minimise the influence of background noise and resonances on the calculation of the time delay estimate, band-pass filters are often used to supress undesirable frequency components of the noise. The objective of this paper is to investigate the influence of resonances in the pipe system (pipe, valves, connections and hydrants), on the time delay estimate calculated using acoustic signals. Analytical models and actual leak data collected in a bespoke rig located in the United Kingdom are used to investigate this feature.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Engenharia Mecânica - FEG

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The oral anticoagulants (AOC) and platelet antiagregants are drugs used for the prevention of thromboembolic phenomena, such as pulmonary embolism in patients with atrial fribrilation heart valves, thrombosis and pulmonary embolism. For patients who are undergoing surgical procedures-dentistry were asked to discontinue the use of anticoagulants until the value of the INR remained = 2.0, that in order to avoid trans and hemorrhages in the postoperative period. However, the AOC can cause the formation of a clot, leading to obstruction of blood pathways. Thus, it became doubtful the medicine for surgery, in which local hemostatic measures would be sufficient to promote hemostasis. Thus, the objective of the review was to evaluate the risk of bleeding in patients AOC users that are subjected to surgical procedures, through a bibliographical survey carried out in relevant clinical studies published between 1990 and 2012, by the MedlinePubMed data. In this review of literature was concluded that the benefit of thromboembolism prevention overcomes the risk hemorrhage, therefore, it is recommended to keep the dose of anticoagulant therapy unchanged for patients undergoing oral surgery and implant dentistry, using appropriate INR levels with the assistance of local hemostatic. In addition, a refined surgical technique should be performed in these patients. With respect to the most invasive oral surgery, with a risk of bleeding, treatment may be necessary in conjunction with the medical staff.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Engenharia Mecânica - FEIS

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The modernization of the world made the speed, accuracy and reliability of all existing processes become increasingly necessary. For this evolution to occur every day, the evolution of the equipment was strategic, but not as much as needed. It is necessary for such equipment to ensure its function and, in case of failure, an early diagnosis to prevent loss. Therefore the evolution of maintainability and reliability in equipment is also paramount. Thus, the growth of forms of maintenance was driven by this scenario, forming maintenance philosophies. Among many, there is the RCM, which have its focus on the identification, parameters development and performance preview. One of those methodologies from this idea is the FMEA, process that has been studied and implemented this work, aiming the anticipation of failure modes and guidance for the use of a heat exchanger and a pump. This implementation has the aid of another process of RCM, the PHA, which was also shown and implemented, these results being used to start the FMEA process. The results show the activities with the highest chance of failure, presenting also the measures to be taken to avoid or minimize them. It is shown, in this paper, concern with the valves because they maintain control and system security, and its flaws related to accidents with possible danger to people and the whole system, emphasizing the priority of action