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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.
361

Terapia celular em modelo experimental do enfisema pulmonar induzido por meio de fumaça de cigarro. / Cell therapy in an experimental model of pulmonary emphysema induced by cigarette smoke.

Nathalia Longhini dos Santos 06 May 2014 (has links)
O enfisema pulmonar é caracterizado pela destruição das paredes alveolares, sendo a fumaça de cigarro o principal agente etiológico. Pretendeu-se, neste estudo, comparar os efeitos terapêuticos do transplante de células mononucleares da medula óssea (BMMC) e células mesenquimais (CTM) em animais com enfisema pulmonar induzido por exposição à fumaça de cigarro. Camundongos fêmeas da linhagem C57Bl6/J foram expostos à fumaça de cigarro durante 90 dias e, 21 dias após o término do período de exposição, receberam BMMC ou CTM derivadas da medula óssea de camundongos machos da linhagem C57Bl6/J, expressando a proteína GFP. As análises morfométricas mostraram que os tratamentos com BMMC e CTM foram eficientes na recuperação do parênquima pulmonar dos animais expostos à fumaça de cigarro. Testes de fluorescência direta e PCR mostraram a migração de BMMC e CTM para o pulmão. Desta forma, pode-se concluir que, morfologicamente, a terapia celular com BMMC ou CTM é eficaz no tratamento do enfisema pulmonar resultante da exposição à fumaça de cigarro em modelo animal. / Pulmonary emphysema is characterized by destruction of alveolar walls, and the cigarette smoking is the main etiologic agent. It was intended in this study to compare the therapeutic effects of the transplantation of bone marrow mononuclear cells (BMMC) and mesenchymal stem cells (MSC) in animals with pulmonary emphysema induced by exposure to cigarette smoke. C57Bl6/J female mice were exposed to cigarette smoke for 90 days and 21 days after the end of the exposure time, received BMMC or MSC derived from bone marrow of C57Bl6/J male mice expressing the GFP protein. The morphometric analysis showed that treatments with BMMC and MSC were efficient in recovering the lung of animals exposed to cigarette smoke. Fluorescence and PCR tests showed the migration of BMMC and MSC to the lung. Thus, it is concluded the cell therapy with BMMC or CTM is morphologically effective in the treatment of pulmonary emphysema resulting from exposure to cigarette smoke in an animal model.
362

Analýza silových účinků v tříbodovém závěsu na výstupní parametry traktoru / Analysis of the force effects in the three-point hitch on the output parameters of the tractor

Rendek, Marek January 2018 (has links)
The diploma thesis deals with the issue of force effects in the three-point hitch links in the multi-body environment depending on the forces ejected to the plow during the plowing. Through simulations, force responses under the tractor wheels are also identified for various conditions. The work is also analyzed for the impact of the upper link attachment relative to the tractor output parameters.
363

Sledování migrace mesenchymálních kmenových buněk v extracelulární matrix / Monitoring of mesenchymal stem cell migration in the extracellular matrix

Zumberg, Inna January 2020 (has links)
This master’s thesis contains a description of mesenchymal stem cells (MSC). The work includes knowledge about the process of migration and differentiation of MSCs. The theoretical part of this thesis also deals with the problem of cell cultivation in 2D and 3D environments. The most used materials for creating 3D scaffolds are described here. The practical part contains the description of the cell culture protocol for passaging and also describes the experiment in the cell laboratory. The results of the experiment are discussed using confocal microscope images. The proposed experiment was tested with a sufficient number of repetitions. The processing of microscopic images was performed in the MATLAB programming environment.
364

Optimální modelování nýtového spoje pomocí metody konečných prvků / Optimal modelling of rivet joints using finite element method

Giorgobiani, Ioseb January 2020 (has links)
Diplomová práce je zaměřena na optimální modelování nýtového spoje pro tři různé konfigurace pomocí metody konečných prvků v programu MSC. Nastran/Patran. Na základě prezentovaných výsledků je možné virtuálně simulovat chování nýtových spojů při zatížení, za účelem správného návrhu před provedením statických pevnostních zkoušek. Použitím těchto MKP simulací v procesu certifikace výrobku lze významně redukovat časovou i finanční náročnost pevnostních zkoušek. Při lepším porozumění chování konstrukce lze také lépe predikovat reálnou únosnost nýtových spojů.
365

Emulátor Mobilní telefonní ústředny / Mobile Switching Centre Emulator

Králíček, Jan January 2013 (has links)
This thesis attempts to provide basic overview of the topic of the GSM system and tries to design Mobile Switching Centre Emulator that could perform the operation Location Update. The first part of this thesis describes the principles and specifics of the GSM network (network structure, the operations required to support user mobility, network entities, etc.). The second part of this thesis describes the SS7 signaling protocols, SIGTRAN and MAP protocol. The final part deals with design of the emulator.
366

Lokale Realisierung von Vektoroperationen auf Parallelrechnern

Groh, U. 30 October 1998 (has links)
For the basic algebraic vector operations several variants of a local implementation on distributed memory parallel computers are presented and discussed systematically. In particular necessary and sufficient conditions are shown for the local realizability of the multiplication matrix by vector.
367

On an automatically parallel generation technique for tetrahedral meshes

Globisch, G. 30 October 1998 (has links)
In order to prepare modern finite element analysis a program for the efficient parallel generation of tetrahedral meshes in a wide class of three dimensional domains having a generalized cylindric shape is presented. The applied mesh generation strategy is based on the decomposition of some 2D-reference domain into single con- nected subdomains by means of its triangulations the tetrahedral layers are built up in parallel. Adaptive grid controlling as well as nodal renumbering algorithms are involved. In the paper several examples are incorporated to demonstrate both program's capabilities and the handling with.
368

Stabilization of large linear systems

He, C., Mehrmann, V. 30 October 1998 (has links)
We discuss numerical methods for the stabilization of large linear multi-input control systems of the form x=Ax + Bu via a feedback of the form u=Fx. The method discussed in this paper is a stabilization algorithm that is based on subspace splitting. This splitting is done via the matrix sign-function method. Then a projection into the unstable subspace is performed followed by a stabilization technique via the solution of an appropriate algebraic Riccati equation. There are several possibilities to deal with the freedom in the choice of the feedback as well as in the cost functional used in the Riccati equation. We discuss several optimality criteria and show that in special cases the feedback matrix F of minimal spectral norm is obtained via the Riccati equation with the zero constant term. A theoretical analysis about the distance to instability of the closed loop system is given and furthermore numerical examples are presented that support the practical experience with this method.
369

Parallel Preconditioners for Plate Problem

Matthes, H. 30 October 1998 (has links)
This paper concerns the solution of plate bending problems in domains composed of rectangles. Domain decomposition (DD) is the basic tool used for both the parallelization of the conjugate gradient method and the construction of efficient parallel preconditioners. A so-called Dirich- let DD preconditioner for systems of linear equations arising from the fi- nite element approximation by non-conforming Adini elements is derived. It is based on the non-overlapping DD, a multilevel preconditioner for the Schur-complement and a fast, almost direct solution method for the Dirichlet problem in rectangular domains based on fast Fourier transform. Making use of Xu's theory of the auxiliary space method we construct an optimal preconditioner for plate problems discretized by conforming Bogner-Fox-Schmidt rectangles. Results of numerical experiments carried out on a multiprocessor sys- tem are given. For the test problems considered the number of iterations is bounded independent of the mesh sizes and independent of the number of subdomains. The resulting parallel preconditioned conjugate gradient method requiresO(h^-2 ln h^-1 ln epsilon^-11) arithmetical operations per processor in order to solve the finite element equations with the relative accuracy epsilon.
370

A numerically stable, structure preserving method for computing the eigenvalues of real Hamiltonian or symplectic pencils

Benner, P., Mehrmann, V., Xu, H. 30 October 1998 (has links)
A new method is presented for the numerical computation of the generalized eigen- values of real Hamiltonian or symplectic pencils and matrices. The method is strongly backward stable, i.e., it is numerically backward stable and preserves the structure (i.e., Hamiltonian or symplectic). In the case of a Hamiltonian matrix the method is closely related to the square reduced method of Van Loan, but in contrast to that method which may suffer from a loss of accuracy of order sqrt(epsilon), where epsilon is the machine precision, the new method computes the eigenvalues to full possible accuracy.

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