Development of procedures for the design, optimization and manufacturing of customized orthopaedic and trauma implants: Geometrical/anatomical modelling from 3D medical imaging

Tese de Doutoramento (Programa Doutoral em Engenharia Biomédica)

Modelagem molecular na caracterização eletrônica de oligopeptídeos e na descrição quântica da interação fármaco-receptor

In this dissertation, the theoretical principles governing the molecular modeling were applied for electronic characterization of oligopeptide α3 and its variants (5Q, 7Q)-α3, as well as in the quantum description of the interaction of the aminoglycoside hygromycin B and the 30S subunit of bacterial ribosome. In the first study, the linear and neutral dipeptides which make up the mentioned oligopeptides were modeled and then optimized for a structure of lower potential energy and appropriate dihedral angles. In this case, three subsequent geometric optimization processes, based on classical Newtonian theory, the semi-empirical and density functional theory (DFT), explore the energy landscape of each dipeptide during the search of ideal minimum energy structures. Finally, great conformers were described about its electrostatic potential, ionization energy (amino acids), and frontier molecular orbitals and hopping term. From the hopping terms described in this study, it was possible in subsequent studies to characterize the charge transport propertie of these peptides models. It envisioned a new biosensor technology capable of diagnosing amyloid diseases, related to an accumulation of misshapen proteins, based on the conductivity displayed by proteins of the patient. In a second step of this dissertation, a study carried out by quantum molecular modeling of the interaction energy of an antibiotic ribosomal aminoglicosídico on your receiver. It is known that the hygromycin B (hygB) is an aminoglycoside antibiotic that affects ribosomal translocation by direct interaction with the small subunit of the bacterial ribosome (30S), specifically with nucleotides in helix 44 of the 16S ribosomal RNA (16S rRNA). Due to strong electrostatic character of this connection, it was proposed an energetic investigation of the binding mechanism of this complex using different values of dielectric constants (ε = 0, 4, 10, 20 and 40), which have been widely used to study the electrostatic properties of biomolecules. For this, increasing radii centered on the hygB centroid were measured from the 30S-hygB crystal structure (1HNZ.pdb), and only the individual interaction energy of each enclosed nucleotide was determined for quantum calculations using molecular fractionation with conjugate caps (MFCC) strategy. It was noticed that the dielectric constants underestimated the energies of individual interactions, allowing the convergence state is achieved quickly. But only for ε = 40, the total binding energy of drug-receptor interaction is stabilized at r = 18A, which provided an appropriate binding pocket because it encompassed the main residues that interact more strongly with the hygB - C1403, C1404, G1405, A1493, G1494, U1495, U1498 and C1496. Thus, the dielectric constant ≈ 40 is ideal for the treatment of systems with many electrical charges. By comparing the individual binding energies of 16S rRNA nucleotides with the experimental tests that determine the minimum inhibitory concentration (MIC) of hygB, it is believed that those residues with high binding values generated bacterial resistance to the drug when mutated. With the same reasoning, since those with low interaction energy do not influence effectively the affinity of the hygB in its binding site, there is no loss of effectiveness if they were replaced.

Propriedades física de molécilas orgânicas e compostos do tipo perovskita CdSiO3 e CaPbO3

In the first part of this work our concern was to investigate the thermal effects in organic crystals using the theory of the polarons. To analyse such effect, we used the Fröhlich s Hamiltonian, that describes the dynamics of the polarons, using a treatment based on the quantum mechanics, to elucidate the electron-phonon interaction. Many are the forms to analyzing the polaronic phenomenon. However, the measure of the dielectric function can supply important information about the small polarons hopping process. Besides, the dielectric function measures the answer to an applied external electric field, and it is an important tool for the understanding of the many-body effects in the normal state of a polaronic system. We calculate the dielectric function and its dependence on temperature using the Hartree-Fock decoupling method. The dieletric function s dependence on the temperature is depicted by through a 3D graph. We also analyzed the so called Arrhenius resistivity, as a functionof the temperature, which is an important tool to characterize the conductivity of an organic molecule. In the second part we analyzed two perovskita type crystalline oxides, namely the cadmium silicate triclinic (CdSiO3) and the calcium plumbate orthorhombic (CaPbO3), respectively. These materials are normally denominated ABO3 and they have been especially investigated for displaying ferroelectric, piezoelectric, dielectrics, semiconductors and superconductors properties. We found our results through ab initio method within the functional density theory (DFT) in the GGA-PBE and LDA-CAPZ approximations. After the geometry optimization for the two structure using the in two approximations, we found the structure parameters and compared them with the experimental data. We still determined further the angles of connection for the two analyzed cases. Soon after the convergence of the energy, we determined their band structures, fundamental information to characterize the nature of the material, as well as their dielectrics functions, optical absorption, partial density of states and effective masses of electrons and holes

Análise vibracional do α-tocoferol

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo da interação entre flavonóides e a albumina do soro humano

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Otimização topológica de transdutores piezelétricos considerando não-linearidade geométrica

Este trabalho aborda o projeto otimizado de transdutores eletro-mecânicos baseados no fenô- meno da piezeletricidade e submetidos a não-linearidade geométrica. Para este m, é proposta uma formulação de equilíbrio para descrever o movimento nito de um corpo piezelétrico e a sua discretização por meio do método dos Elementos Finitos. Problemas de equilíbrio com pontos limites podem ser corretamente simulados com a abordagem de solução proposta, pois questões como a imposição de comprimento de arco em problemas acoplados são discutidas. Diferentes métodos de controle de arco são discutidos e é proposta a consideração do método dos Deslocamentos Generalizados como um tipo de controle de comprimento de arco da família das restrições ortogonais. A formulação de otimização proposta consiste na maximização de componentes do vetor de estado de alguns pontos da estrutura (portas de saída) com restrição de volume e valores de algumas posições do vetor de estado. A análise de sensibilidade proposta, baseada na abordagem adjunta, é su cientemente geral para permitir o projeto de atuadores e sensores e permite a aplicação de condições de contorno essenciais não-homogêneas, como é o caso da diferença de potencial. O método das Assíntotas Móveis Generalizadas (GMMA) é utilizado conjuntamente com a tradicional Programação Linear Sequencial (SLP) para a solução do problema de otimização e suas implementações são discutidas em detalhes. Resultados mostrando a in uência da não-linearidade geométrica e/ou rigidez externa nãolinear no projeto de transdutores piezelétricos são apresentados e discutidos.

Comparação entre um método aproximado e um método numérico para cálculo de deformações em treliças e otimização dessas estruturas

Pretende-se estudar a utilização de um método analítico relativamente básico para cál-culo de deformações em treliças com vãos consideravelmente longos, com o intuito de ajudar o projetista a conceber um futuro projeto antes de conhecer a geometria da estrutura reticulada as-sim como as áreas de secção transversal dos elementos que a compõe. Numa primeira fase é avaliado o grau de aproximação à realidade do método analítico, e numa segunda fase é avaliado o ganho que pode ser obtido por utilização de métodos numéricos, podendo esta dissertação ser dividida em duas partes:  Uma análise estrutural comparativa entre um método analítico aproximado para o cálculo de deformações em treliças e um método numérico obtido a partir de um programa for-mulado para se usar em MATLAB, o PROAES, com o objetivo de avaliar a sua aderência à realidade;  Otimização dessas estruturas, primeiro de topologia para definir quais os elementos que serão necessários para a composição geométrica da treliça e em seguida uma combinação de otimização dimensional com otimização de forma para definir o valor das áreas de secção transversal de cada um dos elementos e a posição dos nós que os unem. Pretende-se também salientar a importância da carga crítica em estruturas do tipo tre-liça, nos elementos sujeitos a esforços normais de compressão, e qual a influência na geometria da estrutura e nas suas dimensões. O programa PROAES torna-se vantajoso face a outros algoritmos de otimização porque tem em conta as derivadas dos constrangimentos em ordem às variáveis consideradas no projeto, o que para além de acelerar o processo de otimização a nível informático, torna-se mais focado na procura de uma solução, na medida em que é um método determinístico e não aleatório, como é o caso, por exemplo, do método dos algoritmos genéticos.

Otimização de forma aplicando B-splines sob critério integral de tensões

This work proposes a computational methodology to solve problems of optimization in structural design. The application develops, implements and integrates methods for structural analysis, geometric modeling, design sensitivity analysis and optimization. So, the optimum design problem is particularized for plane stress case, with the objective to minimize the structural mass subject to a stress criterion. Notice that, these constraints must be evaluated at a series of discrete points, whose distribution should be dense enough in order to minimize the chance of any significant constraint violation between specified points. Therefore, the local stress constraints are transformed into a global stress measure reducing the computational cost in deriving the optimal shape design. The problem is approximated by Finite Element Method using Lagrangian triangular elements with six nodes, and use a automatic mesh generation with a mesh quality criterion of geometric element. The geometric modeling, i.e., the contour is defined by parametric curves of type B-splines, these curves hold suitable characteristics to implement the Shape Optimization Method, that uses the key points like design variables to determine the solution of minimum problem. A reliable tool for design sensitivity analysis is a prerequisite for performing interactive structural design, synthesis and optimization. General expressions for design sensitivity analysis are derived with respect to key points of B-splines. The method of design sensitivity analysis used is the adjoin approach and the analytical method. The formulation of the optimization problem applies the Augmented Lagrangian Method, which convert an optimization problem constrained problem in an unconstrained. The solution of the Augmented Lagrangian function is achieved by determining the analysis of sensitivity. Therefore, the optimization problem reduces to the solution of a sequence of problems with lateral limits constraints, which is solved by the Memoryless Quasi-Newton Method It is demonstrated by several examples that this new approach of analytical design sensitivity analysis of integrated shape design optimization with a global stress criterion purpose is computationally efficient

Otimização do processo de extração e isolamento do antimalárico artemisinina a partir de Artemisia annua L.

Malaria is still one of the major diseases in the world, causing physical and economic problems in tropical regions. Artemisinin (Qinghaosu), a natural compound identified in Artemisia annua L. , is an effective drug mainly against cerebral malaria. The action of this drug is immediate and parasitaemia in the treatment of drug-resistant malaria is rapidily reduced, justifying the industrial production of artemisinin. This article focuses on the industrial production of this potent antimalarial drug, including strategies for enhancing yield using inexpensive and easy steps.

Otimização das condições de produção de ésteres etílicos a partir de óleo de peixe com elevado teor de ácidos graxos ômega-3

The production of ethyl esters by alcoholysis is an alternative for splitting triacylglycerols due to the possibility of using low temperatures, which results in oxidative protection of the polyunsaturated fatty acids. Ethyl esters produced under mild conditions of temperature could be used as substrate for obtaining structured lipids. The reaction parameters of production of ethyl esters from fish oil with high content of omega-3 fatty acids by alcoholysis were optimized using response surface methodology. An experimental design (2³) (with levels +1 and -1, six axial points with levels -alpha and +alpha and three central points) was applied. The variables investigated were concentration of catalyst, amount of ethyl alcohol and temperature. Ethyl ester conversion was monitored by high performance size exclusion chromatography (HPSEC) and the best result obtained was 95% conversion rate. The optimal conditions were 40 °C, 1% of NaOH and 36% of ethanol.

Otimização das condições de extração de saponinas em Ampelozizyphus amazonicus usando planejamento experimental e metodologia de superfície de resposta

This works describes the use of experimental design and surface response methodology for optimization of saponin extraction from Ampelozizyphus amazonicus. For this purpose, a method employing extraction based on maceration assisted by ultrasound technique was utilized. The following factors were studied: extraction length of time and solvent composition. The total saponin was determined by using a gravimetric method and the results expressed by their relative proportion to total crude extract. For the specific condition, 60% hydro-alcoholic solution and 18 minutes extraction length of time has shown the best results. This method can be useful for extraction of substances with biological importance

Modelo dinâmico de simulação e otimização da força normal de reação do solo para um mecanismo de corte basal

The physical model was based on the method of Newton-Euler. The model was developed by using the scientific computer program Mathematica®. Several simulations where tried varying the progress speeds (0.69; 1.12; 1.48; 1.82 and 2.12 m s-1); soil profiles (sinoidal, ascending and descending ramp) and height of the profile (0.025 and 0.05 m) to obtain the normal force of soil reaction. After the initial simulations, the mechanism was optimized using the scientific computer program Matlab® having as criterion (function-objective) the minimization of the normal force of reaction of the profile (FN). The project variables were the lengths of the bars (L1y, L2, l3 and L4), height of the operation (L7), the initial length of the spring (Lmo) and the elastic constant of the spring (k t). The lack of robustness of the mechanism in relation to the variable height of the operation was outlined by using a spring with low rigidity and large length. The results demonstrated that the mechanism optimized showed better flotation performance in relation to the initial mechanism.

Projeto de um cortador de base para colhedora de cana-de-açúcar utilizando otimização matemática

A base-cutter represented for a mechanism of four bars, was developed using the Autocad program. The normal force of reaction of the profile in the contact point was determined through the dynamic analysis. The equations of dynamic balance were based on the laws of Newton-Euler. The linkage was subject to an optimization technique that considered the peak value of soil reaction force as the objective function to be minimized while the link lengths and the spring constant varied through a specified range. The Algorithm of Sequential Quadratic Programming-SQP was implemented of the program computational Matlab. Results were very encouraging; the maximum value of the normal reaction force was reduced from 4,250.33 to 237.13 N, making the floating process much less disturbing to the soil and the sugarcane rate. Later, others variables had been incorporated the mechanism optimized and new otimization process was implemented .

Otimização da eficiência de limpeza em equipamento de beneficiamento de tomate de mesa

The post-harvesting cleaning process in fresh market tomatoes production is essential to the consumer acceptance, since the degree of dirtiness of the fruits is directly related to its quality. However, the washing stage of the cleaning process of commercial packinghouse demands an excessive water volume, bringing serious environmental concerns. The objective of this work was to compare the cleaning efficiency in two cleaning systems through the evaluation of different operational conditions of the cleaning process, related with the brush rotation, water flow and fruit standing time under the system. It was compared the conventional system utilized in commercial equipment with a system using commercial sprays. The results showed that the cleaning efficiency was not directly related to the water volume used, but to the water pressure, standing time and brushes rotation. Therefore, the use of commercial sprays can bring benefits to the cleaning efficiency, increasing it up to 13%, and to the environmental, decreasing water consumption.