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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Myocardial ischemia-reperfusion injury and systemic inflammatory response in high-risk cardiac surgery:a clinical study of the effects of high-dose glucose-insulin treatment and the use of leukocyte-depleting filter

Koskenkari, J. (Juha) 03 October 2006 (has links)
Abstract Cardiac surgery with cardiopulmonary bypass induces the activation of systemic inflammatory response syndrome (SIRS) and results in at least some degree of global myocardial ischemia. Although these responses are usually short-lived, they may lead to serious complications and organ system failures. The present study evaluated the effects of high-dose glucose-insulin (1IU/kg/h) treatment (GIK) administered with the hyperinsulinemic normoglycemic clamp technique and a leukocyte-depleting filter on markers of systemic inflammatory response and myocardial ischemia-reperfusion injury in certain cardiac surgical risk groups. The study involved four prospective randomized controlled clinical trials and 119 patients. Cardioprotective effects were measured as myocardial enzyme release, recovery of contractile function and incidence of arrhythmias in all studies. The hemodynamic and metabolic effects of high-dose glucose-insulin treatment were evaluated in patients admitted for combined aortic valve (AS) and coronary surgery (40) and for urgent coronary surgery (39), and the latter study also involved proinflammatory cytokine and C-reactive protein analyses. The impacts of leukocyte filter on the expression of neutrophil adhesion molecules along with proinflammatory cytokines were evaluated in patients admitted for combined aortic valve (AS) and coronary surgery (20) and for solitary coronary surgery (20). The high-dose glucose-insulin treatment was associated with better preserved myocardial contractile function and less need for inotropic support after combined aortic valve and coronary surgery (I) and attenuation of postoperative CRP release after urgent coronary surgery (II). No effects on postoperative myocardial enzyme release (I, II) or on proinflammatory cytokine responses (II) were detected. The number of hypoglycemic events was low. The use of a leukocyte filter throughout the cardiopulmonary bypass period increased the neutrophil adhesion molecule CD11b expression in patients with both normal and prolonged CPB times and was associated with an enhanced proinflammatory cytokine response (III, IV). In conclusion, high-dose glucose-insulin treatment is safe, but requires strict control of blood glucose level. It reduces the need for inotropic support in patients with compromised cardiac status. The use of leukocyte filter leads to increased leukocyte activation and proinflammatory reaction.
2

Comparação de malhas para problemas de corte e empacotamento / Comparison of grids to cutting and packing problems

Cunha, Jéssica Gabriela de Almeida 22 February 2018 (has links)
Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2018-03-15T20:24:53Z No. of bitstreams: 2 Dissertação - Jéssica Gabriela de Almeida Cunha - 2018.pdf: 3483915 bytes, checksum: 12c37e736c4d6f53761fc0255e6bff6d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-16T11:10:21Z (GMT) No. of bitstreams: 2 Dissertação - Jéssica Gabriela de Almeida Cunha - 2018.pdf: 3483915 bytes, checksum: 12c37e736c4d6f53761fc0255e6bff6d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-16T11:10:21Z (GMT). No. of bitstreams: 2 Dissertação - Jéssica Gabriela de Almeida Cunha - 2018.pdf: 3483915 bytes, checksum: 12c37e736c4d6f53761fc0255e6bff6d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-22 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / This work brings the use of grid of points in the resolution of cutting and packing problems that consider rectangular shaped items. The grids can be considered for mathematical programming models and heuristics, and they are independent of the problem. The following grids that are defined by the literature are considered for this work: canonical dissections (also known as normal patterns), reduced raster points, useful numbers, corner points, regular normal patterns, extreme points, and meet-in-the-middle patterns. The objective is to assess the influence of each grid on the resolution of cutting and packing problems, before and after applying reduction procedures, as the one related to update the items size. Theoretical results are obtained from relations of set and size between the grids, showing that the grid of normal patterns and useful numbers are equivalent and, thus, proving formally that the grid of reduced raster points ensures an optimal solution (this result has been formally opened in the literature). In addition, we propose a new procedure to reduce the size of grids. In order to validate the proposed procedure and evaluate the grids, we perform experiments over instances from the literature, where it is possible to observe that the grids of reduced raster points and meet-in-the-middle patterns are the smallest. Experiments were also conducted in a two-dimensional packing problem that uses an integer linear programming model to pack the items in points of a grid. The results indicate that using the reduction procedures it is possible to obtain optimal solutions quicker. / Este trabalho traz o uso de malhas de pontos na resolução de problemas de corte e empacotamento para itens com formato retangular. As malhas podem ser consideradas em modelos de programação matemática e heurísticas, sendo independentes do problema tratado. As seguintes malhas definidas pela literatura, canonical dissections (também conhecida por normal patterns), reduced raster points, useful numbers, corner points, regular normal patterns, extreme points e meet-in-the-middle patterns, são consideradas neste trabalho. O objetivo é apresentar relações que existem entre as malhas e analisar a influência delas sobre o tempo gasto na resolução de problemas de corte e empacotamento, antes e após aplicar procedimentos de redução, como atualizar o tamanho dos itens. Resultados teóricos são obtidos envolvendo relações de conjunto e tamanho entre as malhas, mostrando que a malha de normal patterns e useful numbers são equivalentes e, assim, permitindo provar formalmente que a malha de reduced raster points garante uma solução ótima (resultado que estava em aberto na literatura). Além disso, propõe-se um novo procedimento visando reduzir o tamanho das malhas. Como forma de validar o procedimento proposto e avaliar a redução que ele proporciona nas malhas, executam-se experimentos sobre instâncias da literatura, sendo possível observar que as malhas de reduced raster points e meet-in-the-middle patterns são as menores. Experimentos também foram realizados sobre um problema de empacotamento bidimensional que utiliza um modelo de programação linear inteira para empacotar os itens em pontos da malha. Os resultados indicam que utilizando os procedimentos de redução é possível obter soluções ótimas mais rapidamente.

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