O cádmio (Cd) é um metal pesado e dos mais abundantes elementos encontrados no ambiente. Existem evidências de sua relação coma osteopenia, osteoporose, e osteomalacia e fragilidade do tecido ósseo. Este estudo visa avaliar o efeito do pH da água de beber na gênese da alteração óssea provocada pela intoxicação por cádmio. Neste estudo, foram utilizados90 ratosWistar (Ratus Norvegicus albinus), adultos, machos,divididos em 6 grupos, aos quais foram administrados: A -solução de cloreto de Cd(400mg/L) com pH neutro (pH 7,0); B -solução de cloreto de Cd(400mg/L) com pH ácido (pH 5,0); C -solução de cloreto de Cd(400mg/L) com pH básico (pH 8,0). D -pH ácido (pH 5,0); E -pH básico (pH 8,0); F -pH neutro (pH 7,0). Nofêmur esquerdo de cada rato avaliou-se a densidade óssea, por meio do densitômetro de dupla emissão (DEXA), ensaiosbiomecânicos e escala de HU na tomografia computadorizada espiral.Os resultados demostram que a densidade óssea reduziunos grupos que receberam cádmio e no grupo sem administração de cádmio para o pH 5 ocorreu uma redução da densidade mineral óssea (DMO) e do conteúdo mineral ósseo (CMO). A rigidez biomecânica mostrou-se aumentada para o grupocom pH 5 sem cádmio. Como conclusão geral o cádmio reduziu a densidade óssea. / The cadmium (Cd) is a heavy metal, one of the most abundant elements found in the environment. There are evidences of its relationship in osteopenia, osteoporosis e osteomalacia and fragility of the bone tissue. This study aims to evaluatethe effect of the pH of the drinking water in the bonealteration origin caused by cadmium intoxication. This study envolved90 wistar rats (Ratus Norvegicus albinus), adults, males,divided in 6groups, were witch one receved: A -cadmium choride solution (400mg/L)withneutral ph (pH 7,0); B -cadmium choride solution(400mg/L) with acid ph (pH 5,0); C -cadmium choride solution(400mg/L)with basic ph(pH 8,0); D -with acid ph (pH 5,0); E -basic ph (pH 8,0); F -neutral pH (pH 7,0).Left femurs from each rat were evaluatedbybone density,DEXA,biomechanictest,HU scale from computerized tomography. The results shows that bone density became lower in the groups that received cadmium. In that wich received no cadmium with pH 5 ocurred an lower level of bone mineral density (BMO) andbone mineral content (BMC).The bone rigidity proved increased in the pH 5 with no cadmium. As a general conclusion, cadmium reduced the bone density.

Introduction. The etiology of adolescent idiopathic scoliosis (AIS) is largely unknown. AIS was well-documented to be associated with low bone mineral density (BMD) and abnormal bone quality. We hypothesized that bone matrix mineralization is abnormally low in AIS and that the abnormality could lead to the observed osteopenia and abnormal bone quality that might contribute to the etiopathogenesis of AIS. / Objectives. 1. To verify the abnormal bone mass and bone quality in AIS Vs normal matched controls 2. To study the bone matrix mineralization status, micro-architecture and mechanical property in AIS Vs controls 3. To study the cellular and molecular characterization of bone formation and resorption in AIS Vs controls 4. To study the possible association of abnormal bone quality with the curve progression / Methods. 1. The case-control study in Chapter 3 included 257 AIS and 187 age- and gender-matched normal controls. BMD and bone quality were measured with dual-energy X-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT) in vivo. 2. Chapter 4 studied iliac crest bone biopsies from 28 AIS and 9 controls. Bone mineral status was measured with DXA, micro-computed tomography (micro-CT) and energy dispersive X-ray spectroscopy; bone micro-architecture and mechanical property were measured with micro-CT, individual trabeculae segmentation analysis and finite element analysis (FEA). 3. Chapter 5 included 46 AIS and 23 controls. The mRNA expression of the bone tissue and primary osteoblastic and osteoclastic activities related to bone mineralization were studied. 4. Chapter 6 included 82 AIS patients. Bone quality was measured with HR-pQCT in vivo at baseline. Comparison was made between the stable and the progressive patients followed for more than 1.5 years after skeletal maturity. / Results. 1. In Chapter 3, both osteopenic and non-osteopenic AIS had lower areal BMD (aBMD) and trabecular and cortical volumetric BMD (vBMD) than their matched normal controls, with the non-osteopenic AIS reaching statistical significance (P<0.05). Osteopenic AIS had larger cortical perimeter and trabecular area than the osteopenic controls after adjustments of confounding factors (P<0.05); non-osteopenic AIS had significantly lower cortical area, thickness and vBMD than the non-osteopenic controls (P<0.05), and marginally significant cortical area and thickness after adjustments. 2. In Chapter 4, AIS had lower bone calcium content (Ca/C ratio) in trabecular bone than controls (P<0.05); moreover, AIS had significantly lower trabeculae rod number and thickness and mechanical property (P<0.05). Osteopenic AIS had significantly lower rod and plate micro-architecture (P<0.05) and 11.3% of decline of FEA mechanical property than non-osteopenic AIS. 3. In Chapter 5, AIS had lower expression of osteogenic markers (ALP and RUNX2) (P=0.009-0.132) and higher expression of extracellular matrix markers (COL1 and BGLAP) (P =0.109-0.132) in bone formation, and higher expression of bone resorption markers (TRAP and CTSK) (P =0.045-0.100). AIS also showed lower osteogenic differentiation potential and calcium nodule formation ability than controls. Within the subgroups, osteopenic AIS showed lower osteoblastic differentiation (P=0.009) and 41.8% decline of calcium formation abilities (P =0.186). The primary osteoblasts from the osteopenic AIS had higher pro-osteoclastogenic potential (P =0.034) and higher osteoclastogenic differentiation potential on osteoclasts. 4. In Chapter 6, progressive AIS had significantly lower aBMD, total vBMD and lower cortical area and thickness after adjustments (P<0.05). The predictive model showed that bone quality model was more predictive than the aBMD model which was more predictive than the basic model on curve progression. / Discussions The present study verified all the AIS had lower BMD and abnormal bone quality. It provided a direct evidence of lower calcium content in AIS which might contribute to the observed lower BMD. Therefore, these abnormalities in AIS could represent a spectrum of severity which is labeled as osteopenic or non-osteopenic with DXA and partly explained by the cellular and molecular studies. The longitudinal study showed AIS with poorer bone quality have significantly higher probability of curve progression. In summary, the present findings supported and confirmed our proposed hypothesis. / 引言：有研究提示AIS低骨量與骨質量異常與病因學有關。我們推測，AIS的骨基質礦化可能異常降低，進而導致低骨量和異常骨質量發生，這可能與AIS病因学有關。 / 目的：1. 驗證AIS的低骨量及骨質量異常 2. 调查AIS骨基質礦化、骨微結構和機械性能狀態 3. 研究AIS關於骨礦化的細胞分子功能 4. 探讨AIS骨質量與側彎進展間的關聯 / 方法：1. 通過雙能吸收儀和高分辨率外周定量CT比较低骨量和非低骨量AIS与其正常對照間骨密度和骨質量的差异 2. 通過雙能吸收儀、顯微CT和掃描電鏡與能量色散光譜儀檢測骨礦物質含量，及顯微CT、骨小梁個體分割和有限元分析法檢測骨微結構和力學性能，比較AIS和正常對照及AIS亞組間的差異。3. 通過檢測與骨礦化相關的mRNA，和原代成骨和破骨細胞培養，比較AIS和正常對照及AIS亞組間的差異。4. 通過高分辨率外周定量CT縱向隨診AIS患者，比較進展組和穩定組間骨質量差異。 / 結果：1. 低骨量和非低骨量AIS均比正常對照組骨密度和骨質量降低。2. AIS骨鈣含量降低，骨微結構和機械性能顯著異常。3. AIS骨形成標記物降低、骨吸收標記物升高，成骨分化潛能降低。低骨量AIS比非低骨量AIS成骨細胞分化能力降低和親破骨分化潛能升高。4. 側彎進展AIS骨密度和骨質量顯著異常。 / 討論：本研究結果支持我們的假設：AIS骨基質礦化異常，導致低骨量和異常骨質量，提示與AIS發病機理相關聯。 / Wang, Zhiwei. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 243-261). / Abstracts also in Chinese; appendixes includes Chinese. / Title from PDF title page (viewed on 09, September, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

Cheung Siu-king. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves [103-113]). / Abstracts in English and Chinese. / ACKNOWLEDGMENT --- p.i / TABLE OF CONTENTS --- p.ii / LIST OF ABBREVIATIONS --- p.vi / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.ix / ABSTRACT (ENGLISH VERSION) --- p.x / ABSTRACT (CHINESE VERSION) --- p.xii / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1. --- ADOLESCENT IDIOPATHIC SCOLIOSIS --- p.1 / Chapter 1.1.1. --- prevalence and geographic patterns of ais --- p.1 / Chapter 1.1.2. --- CLINICAL ASPECTS OF AIS --- p.3 / Chapter 1.1.3. --- ETIOLOGY OF AIS --- p.8 / Chapter 1.2. --- OBJECTIVES OF THIS STUDY --- p.24 / Chapter 2. --- SUBJECTS AND METHODS --- p.25 / Chapter 2.1. --- STUDY DESIGN --- p.25 / Chapter 2.2. --- SUBJECTS RECRUITMENT --- p.25 / Chapter 2.2.1. --- ais subjects --- p.25 / Chapter 2.2.2. --- control subjects --- p.25 / Chapter 2.2.3. --- GROUPING ACCORDING TO THE CHRONOLOGICAL AGE --- p.26 / Chapter 2.2.4. --- informed Consent --- p.26 / Chapter 2.2.5. --- EVALUATION OF COBB'S ANGLE --- p.26 / Chapter 2.3. --- ANTHROPOMETRIC ASSESSMENTS --- p.26 / Chapter 2.4. --- BMD MEASUREMENTS --- p.28 / Chapter 2.4.1. --- measured by dexa --- p.28 / Chapter 2.4.2. --- measured by pqct --- p.30 / Chapter 2.5. --- BONE FORMATION MARKER ： BALP --- p.32 / Chapter 2.5.1. --- SERUM COLLECTION --- p.32 / Chapter 2.5.2. --- ABBOTT METHODS FOR SERUM ALP ACTIVITY --- p.32 / Chapter 2.6. --- BONE RESORPTION MARKER ： DPD --- p.34 / Chapter 2.6.1. --- PYRILINK-D KITS REAGENT --- p.34 / Chapter 2.6.2. --- CREATININE ASSAY --- p.34 / Chapter 2.7. --- GENETIC MARKER - POLYMORPHISM OF ESTROGEN RECEPTOR GENE --- p.38 / Chapter 2.7.1. --- DIGESTION OF PERIPHERAL BLOOD CELLS --- p.38 / Chapter 2.7.2. --- QUANTITATION OF DNA --- p.39 / Chapter 2.7.3. --- CONFIRMATION OF INTEGRITY OF DNA --- p.39 / Chapter 2.7.4. --- POLYMERASE CHAIN REACTION (PCR) --- p.39 / Chapter 2.7.5. --- REACTION BUFFER --- p.39 / Chapter 2.8. --- STATISTICS --- p.45 / Chapter 3. --- RESULTS --- p.46 / Chapter 3 .1 --- SUBJECT DISTRIBUTION OF AIS AND NORMAL CONTROL --- p.46 / Chapter 3.1.1. --- "mean ages of menarche, breast development and pubic hair development" --- p.47 / Chapter 3.1.2. --- "PUBERTAL STATUES OF DIFFERENT AGE GROUPS EVALUATED BY MENARCHE, BREAST DEVELOPMENT AND PUBIC HAIR DEVELOPMENT" --- p.48 / Chapter 3.2. --- ANTHROPOMETRIC ASSESSMENTS --- p.49 / Chapter 3.2.1. --- OVERALL REVIEW OF ANTHROPOMETRIC ASSESSMENTS --- p.49 / Chapter 3.2.2. --- ANTHROPOMETRIC ASSESSMENTS ACCORDING TO THE CHRONOLOGICAL AGE --- p.50 / Chapter 3.3. --- BMD PROFILE OF AIS PATIENTS --- p.51 / Chapter 3.3.1. --- ABMD MEASURED BY DEXA (OVERALL REVIEW) --- p.51 / Chapter 3.3.2. --- ABMD IN DIFFERENT AGE GROUPS --- p.52 / Chapter 3.3.3. --- VBMD MEASURED BY PQCT (OVERALL REVIEW) --- p.52 / Chapter 3.3.4. --- VBMD IN DIFFERENT AGE GROUPS --- p.53 / Chapter 3.3.5. --- PREVALENCE OF OSTEOPENIA IN AIS PATIENTS --- p.53 / Chapter 3.3.6. --- SYMMETRY OF BILATERAL PROXIMAL FEMUR AND DISTAL TIBIA … --- p.54 / Chapter 3.3.7. --- CORRELATION OF ABMD AND VBMD WITH ANTHROPOMETRIC PARAMETERS AND SPINAL DEFORMITY --- p.54 / Chapter 3.4. --- BONE FORMATION MARKER- BALP --- p.55 / Chapter 3.5. --- BONE RESORPTION MARKER -DPD --- p.56 / Chapter 3.6. --- GENETIC MARKER -ESTROGEN RECEPTOR GENE --- p.57 / Chapter 4 --- DISCUSSION…… --- p.84 / Chapter 4.1 --- BONE MINERAL DENSITY OF AIS PATIENTS --- p.84 / Chapter 4.2 --- ANTHROPOMETRIC MEASUREMENTS --- p.89 / Chapter 4.3 --- BONE BIOCHEMICAL TURNOVER MARKER --- p.91 / Chapter 4.4 --- GENETIC MARKER - ER GENE --- p.97 / Chapter 4.4.1 --- OSTEOPORTIC CANDIDATE GENE- ER GENE --- p.98 / Chapter 4.4.2 --- NO CORRELATION BETWEEN ER GENE AND AIS --- p.99 / Chapter 4.5 --- SUMMARY --- p.100 / Chapter 5. --- CONCLUSION --- p.101 / BIBLIOGRAPHY --- p.XIV / APPENDIX --- p.XXV

Orientador: Mário Jefferson Quirino Louzada / Coorientador: Maria Tereza Nunes / Banca: Keico Okino Nonaka / Banca: José Carlos Silva Camargo Filho / Banca: Ivania Garavello / Banca: João Cesar Bedran de Castro / Resumo: Neste estudo foram avaliadas características ósseas dos fêmures de ratos machos Wistar, em diferentes idades, provendo fundamentação científica para o desenvolvimento de estratégias e mecanismos de prevenção de doenças ósseas. Para tanto, realizou-se a determinação dos parâmetros do fêmur de Rattus novergicus albinus com 2, 4, 6, 12, 14, 16 e 20 meses de idade, utilizando densitometria óssea, ensaio mecânico, análises celulares, análise de volume ósseo percentual, espessura trabecular, número de trabéculas e separação trabecular obtidas por microtomografia computadorizada. Os parâmetros ósseos foram apresentados como média e erro padrão da média, submetidos à análise de variância - ANOVA e teste de Tukey com p<0,05 para comparação entre os grupos. Os resultados indicaram alterações relacionadas com a idade, demonstrando que a força máxima, a rigidez, o material mineral do fêmur, a densidade mineral óssea do colo e cabeça do fêmur, o volume ósseo percentual, a espessura trabecular e a separação entre as trabéculas da cabeça do fêmur apresentaram aumento significativo (p<0,05) aos 12 meses de idade em relação aos animais mais novos e uma diminuição significativa (p<0,05) aos 16 e 20 meses de idade em relação aos animais de 12 meses. Houve menor marcação de TRAP em relação a OC nos animais jovens e adultos (2 e 12 meses de idade). Com base nos achados deste estudo, pode-se concluir que há uma progressão das características ósseas de Rattus novergicus albinus, linhagem Wistar, machos, até 12 meses de idade e uma diminuição dos parâmetros ósseos aos 16 e 20 meses de idade / Abstract: We evaluated the femur bone characteristics of male Wistar rats at different ages, providing scientific basis for the development of strategies and meechanisms for the prevention of bone diseases. For that purpose the determination of the parameters of the femur Rattus novergicus albinus with 2, 4, 6, 12, 14, 16 and 20 months of age using bone densitometry, mechanical testing, cellular analysis, analysis of bone volume percentage, trabecular thickness, trabecular number, and trabecular separation obtained by computed microtomography. The bone parameters were presented as mean and standard error of mean, subjected to analysis of variance - ANOVA and Tukey test with p <0.05 for comparison between groups. The results indicate changes related to age, demonstrating that the maximum strength, the stiffness, the mineral material of the femur, the bone mineral density of the femoral lap and head, the bone volume percentage, the trabecular thickness and the separation between the trabecular of the femoral head, showed a significant increase (p<0,05) at 12 months of age compared to younger animals and a significant decrease (p<0,05) at 16 and 20 months of age compared to animals 12 months. There was a lower mark of TRAP in relation to OC in young and adult animals (2 and 12 months of age). Based on our findings, we can conclude that there is a progression of bone characteristics in Rattus norvegicus albinus, Wistar lineage, males, until 12 months of age and a decrease in bone parameters between 16 and 20 months of age / Doutor

Made available in DSpace on 2014-06-11T19:31:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-22Bitstream added on 2014-06-13T19:40:49Z : No. of bitstreams: 1 coelho_jca_dr_araca.pdf: 844014 bytes, checksum: 4fad635e8e4d47e2b5b74469d27493b1 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Neste estudo foram avaliadas características ósseas dos fêmures de ratos machos Wistar, em diferentes idades, provendo fundamentação científica para o desenvolvimento de estratégias e mecanismos de prevenção de doenças ósseas. Para tanto, realizou-se a determinação dos parâmetros do fêmur de Rattus novergicus albinus com 2, 4, 6, 12, 14, 16 e 20 meses de idade, utilizando densitometria óssea, ensaio mecânico, análises celulares, análise de volume ósseo percentual, espessura trabecular, número de trabéculas e separação trabecular obtidas por microtomografia computadorizada. Os parâmetros ósseos foram apresentados como média e erro padrão da média, submetidos à análise de variância – ANOVA e teste de Tukey com p<0,05 para comparação entre os grupos. Os resultados indicaram alterações relacionadas com a idade, demonstrando que a força máxima, a rigidez, o material mineral do fêmur, a densidade mineral óssea do colo e cabeça do fêmur, o volume ósseo percentual, a espessura trabecular e a separação entre as trabéculas da cabeça do fêmur apresentaram aumento significativo (p<0,05) aos 12 meses de idade em relação aos animais mais novos e uma diminuição significativa (p<0,05) aos 16 e 20 meses de idade em relação aos animais de 12 meses. Houve menor marcação de TRAP em relação a OC nos animais jovens e adultos (2 e 12 meses de idade). Com base nos achados deste estudo, pode-se concluir que há uma progressão das características ósseas de Rattus novergicus albinus, linhagem Wistar, machos, até 12 meses de idade e uma diminuição dos parâmetros ósseos aos 16 e 20 meses de idade / We evaluated the femur bone characteristics of male Wistar rats at different ages, providing scientific basis for the development of strategies and meechanisms for the prevention of bone diseases. For that purpose the determination of the parameters of the femur Rattus novergicus albinus with 2, 4, 6, 12, 14, 16 and 20 months of age using bone densitometry, mechanical testing, cellular analysis, analysis of bone volume percentage, trabecular thickness, trabecular number, and trabecular separation obtained by computed microtomography. The bone parameters were presented as mean and standard error of mean, subjected to analysis of variance - ANOVA and Tukey test with p <0.05 for comparison between groups. The results indicate changes related to age, demonstrating that the maximum strength, the stiffness, the mineral material of the femur, the bone mineral density of the femoral lap and head, the bone volume percentage, the trabecular thickness and the separation between the trabecular of the femoral head, showed a significant increase (p<0,05) at 12 months of age compared to younger animals and a significant decrease (p<0,05) at 16 and 20 months of age compared to animals 12 months. There was a lower mark of TRAP in relation to OC in young and adult animals (2 and 12 months of age). Based on our findings, we can conclude that there is a progression of bone characteristics in Rattus norvegicus albinus, Wistar lineage, males, until 12 months of age and a decrease in bone parameters between 16 and 20 months of age

O cádmio (Cd) é um metal pesado e dos mais abundantes elementos encontrados no ambiente. Existem evidências de sua relação coma osteopenia, osteoporose, e osteomalacia e fragilidade do tecido ósseo. Este estudo visa avaliar o efeito do pH da água de beber na gênese da alteração óssea provocada pela intoxicação por cádmio. Neste estudo, foram utilizados90 ratosWistar (Ratus Norvegicus albinus), adultos, machos,divididos em 6 grupos, aos quais foram administrados: A -solução de cloreto de Cd(400mg/L) com pH neutro (pH 7,0); B -solução de cloreto de Cd(400mg/L) com pH ácido (pH 5,0); C -solução de cloreto de Cd(400mg/L) com pH básico (pH 8,0). D -pH ácido (pH 5,0); E -pH básico (pH 8,0); F -pH neutro (pH 7,0). Nofêmur esquerdo de cada rato avaliou-se a densidade óssea, por meio do densitômetro de dupla emissão (DEXA), ensaiosbiomecânicos e escala de HU na tomografia computadorizada espiral.Os resultados demostram que a densidade óssea reduziunos grupos que receberam cádmio e no grupo sem administração de cádmio para o pH 5 ocorreu uma redução da densidade mineral óssea (DMO) e do conteúdo mineral ósseo (CMO). A rigidez biomecânica mostrou-se aumentada para o grupocom pH 5 sem cádmio. Como conclusão geral o cádmio reduziu a densidade óssea. / The cadmium (Cd) is a heavy metal, one of the most abundant elements found in the environment. There are evidences of its relationship in osteopenia, osteoporosis e osteomalacia and fragility of the bone tissue. This study aims to evaluatethe effect of the pH of the drinking water in the bonealteration origin caused by cadmium intoxication. This study envolved90 wistar rats (Ratus Norvegicus albinus), adults, males,divided in 6groups, were witch one receved: A -cadmium choride solution (400mg/L)withneutral ph (pH 7,0); B -cadmium choride solution(400mg/L) with acid ph (pH 5,0); C -cadmium choride solution(400mg/L)with basic ph(pH 8,0); D -with acid ph (pH 5,0); E -basic ph (pH 8,0); F -neutral pH (pH 7,0).Left femurs from each rat were evaluatedbybone density,DEXA,biomechanictest,HU scale from computerized tomography. The results shows that bone density became lower in the groups that received cadmium. In that wich received no cadmium with pH 5 ocurred an lower level of bone mineral density (BMO) andbone mineral content (BMC).The bone rigidity proved increased in the pH 5 with no cadmium. As a general conclusion, cadmium reduced the bone density.

Orientador: Jorge Kennety Silva Formiga / Coorientadora: Vivian Silveira dos Santos Silva Bardini / Banca : João Maurício Ferraz da Silva / Banca: Denilson Paulo Souza dos Santos / Resumo: Os modelos matemáticos utilizados atualmente para análise variação da densidade óssea quando submetido a estímulos mecânicos, consideram apenas carregamentos estáticos ou a variação dentro de um curto espaço de tempo e permanecendo estático novamente. Esse artigo tem o objetivo de desenvolver dois novos modelos que permitam simular o comportamento do tecido ósseo de remodelagem e determinar as faixas de subcarga e sobrecarga onde ocorrem a reabsorção óssea, quando submetido a estímulos mecânicos variados oscilando no tempo. Tradicionalmente os estudos realizados para determinação da variação da densidade óssea, vem utilizando um modelo adotando uma equação diferencial ordinária (EDO) para analisar essa variação. A partir do modelo dessa EDO, foram desenvolvidas duas novas equações matemáticas para simular o comportamento do tecido ósseo quando submetido à estímulos mecânicos variados no tempo. A primeira equação utiliza uma variação da tensão seguindo o padrão de oscilação de uma onda senoidal e a segunda equação utiliza um padrão de onda resultante da combinação linear entre seno e cosseno. A resolução dessa EDO foi feita utilizando o método de Runge-Kutta de 5ª ordem, um integrador de maior precisão e permitindo uma melhor análise do comportamento do tecido ósseo através dos resultados obtidos com maior precisão para diversos níveis de tensão. A análise dos resultados obtidos através das simulações matemáticas empregando três tipos de carregamentos, estático, variável de ac... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract : The mathematical models currently used for bone density variation analysis when subjected to mechanical stimuli, consider only static loading or variation within a short time and remaining static again. This article aims to develop two new models that allow simulating the behavior of bone remodeling tissue and determine the underload and overload ranges where bone resorption occurs when subjected to varying mechanical stimuli oscillating over time. Traditionally, studies performed to determine bone density variation have been using a model using an ordinary differential equation (ODE) to analyze this variation. From the model of this ODE, two new mathematical equations were developed to simulate the behavior of bone tissue when subjected to varying mechanical stimuli over time. The first equation uses a voltage variation following the sine wave oscillation pattern and the second equation uses a wave pattern resulting from the linear combination of sine and cosine. The resolution of this ODE was performed using the 5th order Runge-Kutta method, a more accurate integrator and allowing a better analysis of bone tissue behavior through the results obtained with greater precision for various stress levels. The analysis of the results obtained through mathematical simulations employing three types of loads, static, variable according to the oscillation of a sine wave and variable through the oscillation of a sine-cosine wave, demonstrated that the behavior of bone tissue in relation to the stimuli Mechanics vary by type of loading. The stress levels applied for the three simulations were the same, but the bone remodeling behavior response was different for each type of loading. The resorption tension range, remodeling tension range and overload range change according to the type of loading applied, demonstrating that bone tissue behavior may ....(Complete abstract click electronic access below) / Mestre

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2010. / Härtill 4 uppsatser.

Diss. (sammanfattning) Linköping : Univ., 2002. / Härtill 7 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.