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Exploring anorganic bovine bone granules as osteoblast carriers for bone bioengineering: a study in rat critical-size calvarial defects

Zambuzzi, Willian F.; Fernandes, Gustavo V. O.; Iano, Flávia G.; Fernandes, Mileni da S.; Granjeiro, José Mauro; Oliveira, Rodrigo Cardoso
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.92%
It is known that current trends on bone bioengineering seek ideal scaffolds and explore innovative methods to restore tissue function. In this way, the objective of this study was to evaluate the behavior of anorganic bovine bone as osteoblast carrier in critical-size calvarial defects. MC3T3-E1 osteoblast cells (1x10(5) cells/well) were cultured on granules of anorganic bovine bone in 24-well plates and after 24 h these granules were implanted into rat critical-size calvarial defects (group Biomaterial + Cells). In addition, other groups were established with different fillings of the defect: Blood Clot (negative control); Autogenous Bone (positive control); Biomaterial (only granules) and Cells (only MC3T3-E1 cells). After 30 days, the animals were euthanized and the calvaria were technically processed in order to allow histological and morphometric analysis. It was possible to detect blood vessels, connective tissue and newly formed bone in all groups. Particularly in the Biomaterial + Cells group, it was possible to observe a profile of biological events between the positive control group (autogenous bone) and the group in which only anorganic bovine granules were implanted. Altogether, the results of the present study showed that granules of anorganic bovine bone can be used as carrier to osteoblasts and that adding growth factors at the moment of implantation should maximize these results.

A bioengenharia no Brasil, século XX: estado da arte; The brazilian’s bioengineering on XX century: art’s state

Antonio, Ana Maria
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/07/2004 PT
Relevância na Pesquisa
37.17%
Apresenta-se uma retrospectiva histórica do conhecimento e aplicação da engenharia biomédica/bioengenharia no Brasil; no período do século XX, enfocando a história da arte brasileira com relação à engenharia biomédica/bioengenharia, evidenciando perspectivas de desenvolvimento deste interessante campo de conhecimento. Por razões metodológicas e didáticas dividirão a engenharia biomédica/bioengenharia em áreas de aplicação: cardiologia, ortopedia, odontologia, oftalmologia, medicina regenerativa coadunando as áreas de ciências exatas e da terra onde, por exemplo, os conhecimentos das propriedades dos materiais utilizados, são evidenciados como composição química, estrutura, propriedades e aplicações, contextualmente definida como aplicação da engenharia biomédica/bioengenharia na medicina, de forma transitória ou permanente pelos diversos tecidos dos organismos dos seres vivos. Eles são utilizados como um todo ou parte de um biológico que trata, restaura ou substitui algum tecido, órgão ou função do corpo humano ou ainda como um material não viável utilizado em um dispositivo médico, com a intenção de interagir com o sistema biológico. A definição de bioengenharia foi encarada nessa dissertação de forma a direcionar a pesquisa de campo em empresas e núcleos que desenvolvem biomateriais...

Desenvolvimento de formulações cosméticas contendo pantenol e avaliação dos seus efeitos hidratantes na pele humana por bioengenharia cutânea; Development of cosmetic formulations containing panthenol and evaluation of their hydration effects on human skin by using Skin Bioengineering Techniques

Camargo Junior, Flavio Bueno de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/11/2006 PT
Relevância na Pesquisa
36.92%
As vitaminas vêm sendo muito utilizadas em cosméticos e dentre elas, o pantenol, por fazer parte da constituição normal da pele e devido as suas propriedades umectantes e cicatrizantes, tem tido destaque para aplicação nesta categoria de produtos. Devido ao interesse e a grande importância da realização de estudos que possam avaliar a influência das vitaminas na estabilidade física de formulações cosméticas, bem como de estudos científicos que comprovem os seus benefícios propostos, o objetivo dessa pesquisa foi o desenvolvimento, a avaliação da estabilidade e a eficácia na hidratação e nas propriedades viscoelásticas de formulações cosméticas contendo diferentes concentrações de pantenol. Para tal, foram desenvolvidas oito formulações, sendo três géis a base de polímeros hidrofílicos (formulações nos 1, 2, e 3), três géis creme a base de polímeros hidrofílicos e microemulsão de silicone (formulações nos 4, 5, e 6) e duas emulsões sendo uma delas a base de álcool batílico e lecitina de soja (formulação no 7) e a outra a base de manteiga de karité e carbômero (formulação no 8). Estas formulações foram acrescidas ou não de 0,5; 1,0 e 5,0% de pantenol e submetidas a testes preliminares de estabilidade. O estudo de estabilidade física foi realizado por determinação do comportamento reológico sendo que...

Projeto e construção de um motor elétrico linear aplicado à bioengenharia; Design and construction of a linear electric motor applied to bioengineering

Juliani, Aline Durrer Patelli
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/01/2011 PT
Relevância na Pesquisa
37.07%
Considerando-se o atual estagio de desenvolvimento das máquinas elétricas, tanto em termos de ferramentas computacionais auxiliares nas simulações e nos projetos, quanto de materiais e sistemas eletrônicos de acionamento e controle, propõe neste trabalho a construção de um dispositivo eletromecânico, na classe dos motores elétricos lineares, que atenda as necessidades e se aplique a bioengenharia, mais propriamente as próteses de membro superior, na forma de acionador translacional. Este dispositivo deve substituir os sistemas que utilizam motores elétricos rotativos com mecanismos de adaptação mecânica (roldanas, vários fios, redutores), que convertem o movimento rotacional em linear. Também, os dispositivos híbridos, como atuadores eletro-hidráulicos e eletropneumáticos, que necessitam de fontes de energia de naturezas diferentes da eletroeletrônica, podem ser substituídos pelas maquinas elétricas lineares. Uma revisão dos conceitos relacionados a área de bioengenharia e feita, destacando-se os mecanismos de transmissão existentes. E apresentada uma analise comparativa entre os principais motores lineares, enfatizando-se as características construtivas, as vantagens e as desvantagens de cada um, relacionados a aplicação. A escolha da maquina a ser projetada e construída recaiu no motor linear síncrono...

Cellular behavior as a dynamic field for exploring bone bioengineering: A closer look at cell-biomaterial interface

Gemini-Piperni, Sara; Takamori, Esther Rieko; Sartoretto, Suelen Cristina; Paiva, Katiucia B. S.; Granjeiro, Jose Mauro; Oliveira, Rodrigo Cardoso de; Zambuzzi, Willian Fernando
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 88-98
ENG
Relevância na Pesquisa
37.07%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Bone is a highly dynamic and specialized tissue, capable of regenerating itself spontaneously when afflicted by minor injuries. Nevertheless, when major lesions occur, it becomes necessary to use biomaterials, which are not only able to endure the cellular proliferation and migration, but also to substitute the original tissue or integrate itself to it. With the life expectancy growth, regenerative medicine has been gaining constant attention in the reconstructive field of dentistry and orthopedy. Focusing on broadening the therapeutic possibilities for the regeneration of injured organs, the development of biomaterials allied with the applicability of gene therapy and bone bioengineering has been receiving vast attention over the recent years. The progress of cellular and molecular biology techniques gave way to new-guided therapy possibilities. Supported by multidisciplinary activities, tissue engineering combines the interaction of physicists, chemists, biologists, engineers, biotechnologist, dentists and physicians with common goals: the search for materials that could promote and lead cell activity. A well-oriented combining of scaffolds...

Desenvolvimento de uma metodologia para analise de bioengenharia em ossos compactos com remodelagem superficial pelo metodo dos elementos de contorno 3D em meios transversalmente isotropicos; Development of a methodology for bioengineering analysis of compact bones with surface remodeling using 3D boundary element method in transversely isotropic media

Pedro Yoshito Noritomi
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/07/2005 PT
Relevância na Pesquisa
37.17%
Este trabalho mostra o desenvolvimento de uma metodologia para análise de problemas de bioengenharia, aplicando modelagem numérica elastostática de tensões e deformações, baseada no método dos elementos de contorno com formulação 3D para meios transversalmente isotrópicos lineares, incluindo a capacidade de simulação do comportamento de remodelagem óssea superficial. A implementação do núcleo transversalmente isotrópico sobre a estrutura básica de análise por elementos de contorno 3D utilizou a solução fundamental proposta por Pan & Chou e revisada por Loloi, tendo exigido o cálculo adicional das soluções fundamentais de força de superfície a partir da derivação das soluções fundamentais de deslocamento. O modelo de remodelagem óssea superficial baseou-se na hipótese de estímulo biológico por campo de deformação, partindo de um modelo 2D, adaptado para o espaço 3D com o uso de deformações principais como grandezas de referência. As implementações foram testadas através de análises numéricas de problemas com solução analítica e validações com resultados de aplicações comerciais baseadas em elementos finitos, para problemas padrão de engenharia, bem como comparações com resultados da literatura para problemas de bioengenharia. A análise dos resultados mostrará que...

A novel engineering systems approach for bioengineering education : the MIT-Portugal collaboration

Tan, Junjay; Newman, Dava J.; Cabral, J. M. S.; Mota, M.; Ponte, Manuel Nunes da
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Conferência ou Objeto de Conferência
Publicado em //2007 ENG
Relevância na Pesquisa
37.24%
This paper discusses the importance of an engineering systems approach to international bioengineering education and how a new educationalresearch program, the MIT-Portugal Program Bioengineering Systems focus area, aims to develop future global bioengineering leaders. The program, comprising both post-graduate advanced studies and doctoral programs, commences in September 2007. Several other international-collaborative educational and research programs—such as the Cambridge-MIT Institute, the Singapore MIT Alliance, and the Socrates/Erasmus “Erasmus Programme”—offer lessons learned in international collaboration. The MPP Bioengineering Systems program differs from these programs in several respects. The unique collaboration in MPP offers an engineering systems approach, a joint degree offered by three Portuguese universities, and collaborative teaching and research efforts between MIT and Portuguese faculty and students.

Exploring anorganic bovine bone granules as osteoblast carriers for bone bioengineering: a study in rat critical-size calvarial defects

Zambuzzi,Willian F.; Fernandes,Gustavo V. O.; Iano,Flávia G.; Fernandes,Mileni da S.; Granjeiro,José Mauro; Oliveira,Rodrigo Cardoso
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
36.92%
It is known that current trends on bone bioengineering seek ideal scaffolds and explore innovative methods to restore tissue function. In this way, the objective of this study was to evaluate the behavior of anorganic bovine bone as osteoblast carrier in critical-size calvarial defects. MC3T3-E1 osteoblast cells (1x10(5) cells/well) were cultured on granules of anorganic bovine bone in 24-well plates and after 24 h these granules were implanted into rat critical-size calvarial defects (group Biomaterial + Cells). In addition, other groups were established with different fillings of the defect: Blood Clot (negative control); Autogenous Bone (positive control); Biomaterial (only granules) and Cells (only MC3T3-E1 cells). After 30 days, the animals were euthanized and the calvaria were technically processed in order to allow histological and morphometric analysis. It was possible to detect blood vessels, connective tissue and newly formed bone in all groups. Particularly in the Biomaterial + Cells group, it was possible to observe a profile of biological events between the positive control group (autogenous bone) and the group in which only anorganic bovine granules were implanted. Altogether, the results of the present study showed that granules of anorganic bovine bone can be used as carrier to osteoblasts and that adding growth factors at the moment of implantation should maximize these results.

Bioengineering Human Microvascular Networks in Immunodeficient Mice

Lin, Ruei-Zeng; Melero-Martin, Juan M.
Fonte: MyJove Corporation Publicador: MyJove Corporation
Tipo: Artigo de Revista Científica
Publicado em 11/07/2011 EN
Relevância na Pesquisa
36.92%
The future of tissue engineering and cell-based therapies for tissue regeneration will likely rely on our ability to generate functional vascular networks in vivo. In this regard, the search for experimental models to build blood vessel networks in vivo is of utmost importance 1. The feasibility of bioengineering microvascular networks in vivo was first shown using human tissue-derived mature endothelial cells (ECs) 2-4; however, such autologous endothelial cells present problems for wide clinical use, because they are difficult to obtain in sufficient quantities and require harvesting from existing vasculature. These limitations have instigated the search for other sources of ECs. The identification of endothelial colony-forming cells (ECFCs) in blood presented an opportunity to non-invasively obtain ECs 5-7. We and other authors have shown that adult and cord blood-derived ECFCs have the capacity to form functional vascular networks in vivo7-11. Importantly, these studies have also shown that to obtain stable and durable vascular networks, ECFCs require co-implantation with perivascular cells. The assay we describe here illustrates this concept: we show how human cord blood-derived ECFCs can be combined with bone marrow-derived mesenchymal stem cells (MSCs) as a single cell suspension in a collagen/fibronectin/fibrinogen gel to form a functional human vascular network within 7 days after implantation into an immunodeficient mouse. The presence of human ECFC-lined lumens containing host erythrocytes can be seen throughout the implants indicating not only the formation (de novo) of a vascular network...

The toxicity and mutagenicity of the aflatoxin B₁ formamidopyrimidine DNA adduct

Smela, Maryann E. (Maryann Elizabeth), 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 222 leaves; 13542136 bytes; 13541895 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
36.92%
Aflatoxin B1 (AFB1) is a fungal metabolite that contaminates the food supply in certain areas of the world. It is produced by Aspergillusflavus and related fungi that grow on improperly stored foods such as corn, rice, and peanuts. Epidemiological studies have shown a correlation between exposure to AFBI and incidence of hepatocellular carcinoma (HCC). Mutations in p53 are observed in over 50% of the HCC samples studied, and a unique mutational hotspot occurs at the third position of codon 249 in this gene, yielding almost exclusively GC to TA transversions. It is of interest to evaluate the mutagenic properties of specific chemical structures of AFBI adducts in order to determine which of these may be responsible for the mutations that may play a role in the formation of HCC. The primary DNA adduct formed by the epoxide of AFB is the 8,9-dihydro-8-(N7-guanyl)-9-hydroxyaflatoxin B1 (AFBI-N7-Gua) adduct, which can lead to two secondary lesions, an apurinic site or a ring opened formamidopyrimidine (FAPY) adduct, which itself has two rotameric forms. This study focuses on of the determination of how well cells tolerate each of the AFB1-FAPY rotamers and of the type and frequency of mutations caused by the persistent AFB I-FAPY adduct in a site specifically modified M13 viral vector transfected into E. coli. Four major results were concluded from this work. First...

Analysis of community cancer mortality rates

Vatland, Janice A. (Janice Audrey)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 195 leaves; 8480365 bytes; 8480124 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
36.92%
by Janice A. Vatland.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Division of Bioengineering and Environmental Health, 2001.; Includes bibliographical references (leaves 186-193).

Investigations into therapeutic discovery and delivery of heparin-like glycosaminoglycans

Liu, Dongfang, 1969-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 153 p.; 7898927 bytes; 7898736 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
36.92%
Heparin-like glycosaminoglycans (HLGAGs) are complex polysaccharides found both in extracellular matrix (ECM) and at the cell surface where they, in a sequence-specific manner, bind to and regulate the biological activity of numerous proteins. Due to a lack of effective tools to study structure-function relationship of these complex molecules, the role(s) of HLGAGs in cancer remains largely indirect and poorly understood. To study the role(s) of HLGAGs in cancer growth, metastasis and angiogenesis, tumor systems were studied using heparinases I and III which have distinct substrate specificities. Studies, focusing on the biochemistry of the heparinase active site, elucidated key interactions important for enzymatic activities, thus enabling the biological studies presented here. In vitro cell culture study with heparinases as tools clearly showed that cell surface HLGAGs are involved in regulating fundamental cellular activities including cell proliferation, invasion and adhesion. Significantly, heparinase I and III demonstrated distinct effect on these cellular activities with heparinase III inhibiting tumor cell proliferation, invasion and adhesion in selected model systems and heparinase I inhibiting these processes. Further in vivo studies in animal tumor models confirmed and expanded the distinct responses to heparinase I and III treatment. HLGAG fragments generated from heparinase treatment were found to be responsible for the effect of heparinase treatment in tumor models. Moreover...

BE.010J / 2.790J / 6.025J / 7.38J / 10.010J Introduction to Bioengineering, Spring 2005; Introduction to Bioengineering

Matsudaira, Paul T.; Belcher, Angela M.; Grodzinsky, Alan J.
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
EN-US
Relevância na Pesquisa
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Designed as a freshmen seminar course, faculty from various School of Engineering departments describe the research and educational opportunities specific to and offered by their departments. Background lectures by the BE.010J staff introduce students to the fundamental scientific basis for bioengineering. Specially produced videos provide additional background information that is supplemented with readings from newspaper and magazine articles.

BE.010J Introduction to Bioengineering, Spring 2006; Introduction to Bioengineering

Belcher, Angela M.; Matsudaira, Paul T.; Lauffenburger, Douglas A.
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
EN-US
Relevância na Pesquisa
37.4%
Designed as a freshmen seminar course, faculty from various School of Engineering departments describe the research and educational opportunities specific to and offered by their departments. Background lectures by the BE.010J staff introduce students to the fundamental scientific basis for bioengineering. Specially produced videos provide additional background information that is supplemented with readings from newspaper and magazine articles. Description from course home page: Bioengineering at MIT is represented by the diverse curricula offered by most Departments in the School of Engineering. This course samples the wide variety of bioengineering options for students who plan to major in one of the undergraduate Engineering degree programs. The beginning lectures describe the science basis for bioengineering with particular emphasis on molecular cell biology and systems biology. Bioengineering faculty will then describe the bioengineering options in a particular engineering course as well as the type of research conducted by faculty in the department.

Quantification of benzo[a]pyrene-diol-epoxide adducts by laser-induced fluorescence spectroscopy

Özbal, Can Cemil, 1971-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 188 leaves
ENG
Relevância na Pesquisa
36.92%
by Can Cemil Özbal.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Division of Bioengineering and Environmental Health, 1999.; Includes bibliographical references.

Determination of the historical changes in primary and secondary risk factors for cancer using U.S. public health records

Herrero Jimenez, Pablo, 1972-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 354 p.
ENG
Relevância na Pesquisa
36.92%
Overall cancer mortality rates have risen from about 4% of all deaths in the early 20th century to about 25% of all deaths by the end of the century in the United States. To assess any potential hypotheses for this increase required knowledge of the mortality rate changes specific to each form of cancer, and the time points when these rates had changed. For this purpose, population and cancer mortality data of the U.S. were collected and organized to create age-specific mortality rates for each birth decade from the 1800s forward, delineated by the organ of incidence. Concurrently, cancer survival data were collected so as to correct for any effect of improved treatment on historical changes in cancer mortality rates. To analyze these data, a mathematical model for the three-stage process of carcinogenesis (initiation, promotion, and progression) was developed to estimate for each birth decade cohort the value of the fraction of the cohort at lifetime risk for that cancer, the value of the growth rate of the respective precancerous lesion, and the values for the mutation rates of normal and precancerous cells in the organ of incidence. This methodology permits the analysis of the potential historical effect of new chemical exposures during the last century on cancer mortality rates. These chemical exposures represent potential risk factors that determine the fraction of the population at risk of developing cancer (lifetime...

A clamp ligation method for point mutational spectrometry : marked increase in scanning range for the human genome

Kim, Andrea Seungsun, 1971-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 200 leaves
ENG
Relevância na Pesquisa
36.92%
The study of human mutagenesis requires methods of measuring somatic mutations in normal human tissues and inherited mutations in human populations. Such methods should permit measurement of rare mutations in the presence of abundant wild-type copies and should be general to the human genome. A sensitivity of 2 x 10-6 for point mutations was recently achieved in human cells using a novel method of target isolation, constant denaturant capillary electrophoresis (CDCE), and high-fidelity polymerase chain reaction (hifi-PCR) (Li-Sucholeiki and Thilly, 2000). This method is applicable to 100-base pair (bp) DNA domains juxtaposed with a naturally occurring domain of a higher melting temperature, or a natural clamp. Such sequence domains represent about 9% of the human genome. To permit analysis of rare point mutations in the human genome more generally, this thesis developed a procedure in which a clamp can be ligated to any 100-bp sequence of interest. This procedure was combined with the previous method to create a new method of point mutational analysis that is not dependent on a naturally occurring clamp. To demonstrate the new method, a sequence with a natural clamp, a part of the human hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene (cDNA-bp 223-318)...

Avaliação do campo acústico gerado pelos aparelhos de ultra-som terapêutico do programa de pós-graduação interunidades em bioengenharia, de acordo com a norma NBR-IEC 1689; Evaluation of the acoustic field produced by the therapeutic ultrasound apparatus of Interunits Postgraduate Program in Bioengineering according with NBR-IEC 1689

Valentini, Elton Antonio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 13/03/2006 PT
Relevância na Pesquisa
37.24%
O uso do ultra-som na área da saúde é bastante amplo, tanto para o diagnóstico por imagem como para o tratamento de inúmeras afecções (de feridas de pele a tumores malignos). No Programa de Pós-Graduação Interunidades em Bioengenharia há mais de 20 anos são feitas pesquisas sobre a interação do ultra-som com os tecidos biológicos. O presente trabalho objetiva avaliar os campos acústicos gerados pelos aparelhos de ultra-som terapêutico usados no Programa de Pós Graduação Interunidades em Bioengenharia de acordo com a norma NBR-IEC 1689. Para isto foi montado um tanque acústico e um sistema de posicionamento para a avaliação dos aparelhos, bem como foi desenvolvido um software para controle e automação do sistema. Os parâmetros que a norma pede que sejam avaliados e seu respectivo intervalo de tolerância são: potência de saída ('+ OU -' 20%); área de radiação efetiva ('+ OU -' 20%); intensidade efetiva ('+ OU -' 20%); freqüência de trabalho acústica ('+ OU -' 10%); relação de não-uniformidade do feixe ('+ OU -' 30%); intensidade máxima do feixe; tipo de feixe; fator de operação; forma de onda de modulação. Foram avaliados 8 aparelhos, sendo que 3 deles usados no ambulatório da bioengenharia e 5 usados em pesquisa. Para se avaliar os parâmetros dos equipamentos é necessário que eles estejam declarados no equipamento ou em manual que acompanha o equipamento. Na falta destas especificações fez se necessário a proposta de valores de referência para os aparelhos de ultra-som terapêutico da bioengenharia; The use of the ultrasound is quite wide health area...

Nitric oxide : cellular effects in vitro and in vivo

Wright, Teresa Leah, 1970-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 170 leaves; 9263085 bytes; 9262842 bytes; application/pdf; application/pdf
ENG
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The overall aim of this project was to investigate various cellular responses and toxic effects of nitric oxide, NO' and in vitro and in vivo. Nitric oxide gives rise to a complex spectrum of reactive species in oxygenated solution. The complexity of nitric oxide's chemistry is recapitulated in its effects on cells. Exposure to nitric oxide can result in changes on many different levels in cells ranging from protein and DNA damage, to damage to organelles and changes in gene expression, and even in cell death. Many models to study nitric oxide have been developed and will be used to study various responses to nitric oxide and related species. Nitric oxide and peroxynitrite-induced cellular damage has been and continues to be studied extensively using in vitro systems. Two systems have been used in this project, a delivery system for NO' as well as a cell line, which produces NO'. A Silasticʾ membrane delivery system can be used to treat bacteria or cells to mimic in vivo exposure to nitric oxide. Mutations induced by nitric oxide in a set of Salmonella tester strains can be studied utilizing this delivery system. Activated RAW264.7 macrophage cells have been used as an in vitro model of nitric oxide production and cytotoxicity SJL/J mice bearing the transplantable lymphoma RcsX have been established as an in vivo model of nitric oxide production and toxicity.; (cont.) This in vivo mouse model can be used to test results found in vitro. Specifically...

Sequencing complex polysaccharides

Shriver, Zachary (Zachary Holmes), 1973-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 140 leaves; 15464392 bytes; 15464198 bytes; application/pdf; application/pdf
ENG
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36.92%
Glycosaminoglycans are complex polysaccharides that exist at the cell/extracellular matrix interface. As such, these information-dense molecules are key regulators of extracellular signals. However, to date, there has been a lack of effective biochemical and analytical tools for the analysis of glycosaminoglycan structure and hence, there is very little understanding of exactly how glycosaminoglycan structure impinges on function. Development of such tools is especially important for a key subset of glycosaminoglycans, i.e., heparin/heparan sulfate-like glycosaminoglycans (HLGAGs). As a first step in the development of tools to study HLGAG structure, biochemical studies were completed on the heparinases, a family of three HLGAG-degrading enzymes from Flavobacterium heparinum. With heparinase I, it was found that calcium is a necessary cofactor for optimal activity and that two putative calcium coordinating motifs exist in heparinase I. With heparinase II, a single cysteine and three histidines were found to be critical for proper enzymatic function. Finally, with heparinase III, two histidines were found to be catalytically important.; (cont.) In addition to the development of the heparinases, sensitive analytical methodologies were developed to determine HLGAG structure. A novel mass spectrometric procedure was developed and used to define heparinase's II mechanism of action on defined oligosaccharide substrates. In addition...