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COB60 Flow Visualization of Heart Valves Prostheses in a Steady Flow Model

Edson D.R. Vieira, Éverton Dall’Agnol, Emanuel R.Woiski, Sérgio S. Mansur

Departamento de Engenharia Mecânica, Faculdade de Engenharia, UNESP - Ilha Solteira

CEP 15.385-000 Ilha Solteira - SP, Brasil, E-mail: delrio@feis.unesp.br

Ricardo A. Mazza

Departamento de Energia, Faculdade de Engenharia Mecânica, UNICAMP, Campinas - SP, Brasil,

Marcos Pinotti

Departamento de Engenharia Hidráulica e Recursos Hídricos, Faculdade de Engenharia, UFMG, Belo Horizonte - MG, Brasil

Domingos M. Braile

Braile Biomédica Ind. Com. e Rep. S.A., São José do Rio Preto - SP, Brasil

Although prosthetic heart valves have been used successfully for many years, an ideal prostheses has not been developed yet. Since the major part of heart valve prostheses related complications are due to flow disturbances, valve hydrodynamic characterization is an useful aid in designing new prostheses. In the present report, flow visualization in steady state flow model has been employed to study flow disturbances occurring downstream two types of bioprosthesis (porcine and bovine pericardium) tested in the mitral position. Flow visualization is an important tool for prosthetic valves evaluation using simple and low cost facilities.

Keywords: Flow visualization; dye injection; cardiac bioprosthesis; heart valves testing; steady flow; visualização de escoamento; injeção de corante líquido; biopróteses cardíacas; teste de válvulas cardíacas; escoamento não-pulsátil.

COB123 DUREZA DAS RESINAS ODONTOLÓGICAS E QUANTIDADE DE RADICAIS DETERMINADAS POR ESR / HARDNESS OF DENTAL COMPOSITES AND AMOUNT OF RADICALS DETERMINED BY ESR

Walter Sano & Cristina Barkevui Mekitarian de Mello

Departamento de Física Aplicada, Instituto de Física - USP - 05315-970 São Paulo, SP Brasil E-mail: sano@if.usp.br

Light-curing composite resins even being today one of the most used in restorative dental works its photo-polymerization process had not been completely explained. The type containing Bis-GMA and inorganic charge of zircon and silica was studied after its activation by a conventional visible light unit. Electron Spin Resonance (ESR) spectra were obtained along one month, commencing immediately after the activation and then recording periodically, so obtaining the decay over time of the relative number of the free radicals. A post-curing evidence was observed in agreement with Watts et al., 1987 who have been reported the evolution of the hardness number over time of similar materials. Analyzing the decay of the ESR intensity after the light activation, it is concluded that the resin cure process is due to the remaining radicals. Firstly half of them is converted in 1.2 days, in agreement with the results of the hardness number which starts from 45% and in one day attains 90% of the maximum value. Latterly they decay more slowly, with half-life of 12.6 days, also in agreement with the hardness number which reaches 96% in one week and tends to 100% in one month.

Keywords: dureza, resina odontológica, resina composta, radical livre, ressonância de spin eletrônico / hardness, dental composite, free radical, ESR

COB175 DINÂMICA DA INTERAÇÃO ENTRE O SISTEMA IMUNOLÓGICO E O VÍRUS HIV DYNAMICS OF THE INTERACTION BETWEEN IMMUNE SYSTEM AND HIV

Tiago Rodrigo Alves de Souza

Departamento de Engenharia Mecânica, Universidade de Brasília, 70.910.900, Brasília, DF - E-Mail: tiagor@guarany.cpd.unb.br

Marcelo Amorim Savi

Departamento de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia

22.290.270, Rio de Janeiro, RJ - E-Mail: d4savi@epq.ime.eb.br

The immune system is a complex network of organs containing cells that provides the means to make rapid, highly specific, and in general very protective responses against different pathogens. The acquired immunodeficiency syndrome (AIDS) occurs as a consequence of HIV action on organisms. The virus enters the bloodstream and destroys certain white blood cells, called T lymphocytes, that play a key role in the functioning of the immune system. AIDS impairs the immune system and leaves the victim susceptible to various opportunistic infections. This contribution evaluates the dynamical interaction between immune system and HIV described by the model proposed by Holton & May (1993). Initially, a discussion about immune system, HIV and AIDS is done. Then, the mathematical model is presented. Some numerical simulations are considered.

Keywords: Non-linear Dynamics, HIV/AIDS Dynamics, Biomechanics. / Dinâmica Não-Linear, Dinâmica HIV/AIDS, Biomecânica.

COB177 MODELOS CONSTITUTIVOS VISCOELÁSTICOS PARA O PULMÃO:CASO UNIDIMENSIONAL VISCOELASTIC CONSTITUTIVE MODELS FOR THE LUNG: ONE DIMENSIONAL CASE

Marcelo Amorim Savi

Departamento de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia, 22.290.270, Rio de Janeiro, RJ

E-Mail: d4savi@epq.ime.eb.br

Pedro Manuel Calas Lopes Pacheco

Departamento de Engenharia Mecânica, CEFET/RJ, 20.271.110, Rio de Janeiro, RJ - E-Mail: calas@cefet-rj.br

The simulation of vital phenomena may contribute either to define best conditions for living beings or to determine pathological treatments. These simulations need models which are capable to describe the behavior of biological systems. The simulation of respiratory system may contribute to evaluate some physiologic details of this system. Usually, constitutive models used to describe mechanical behavior of the lung is a combination of models to describe the biological tissue behavior associated with models to describe the surface tension stress effect in the alveolar walls. This work presents an overview of constitutive models for soft tissues and suggests viscoelastic models to describe the complete response of the lung. Polynomial and exponential models are considered to describe the elastic behavior of biological tissue. Some viscoelastic models are presented and discussed. One-dimensional results illustrate with qualitative coherence the stress-strain curves prescribed by these models.

Keywords: Constitutive Equations, Mechanics of Lungs, Biomechanics. Equações Constitutivas, Mecânica do Pulmão, Biomecânica.

COB199 MODELADO DE LA COLUMNA VERTEBRAL PARA PATOLOGIA LUMBAR.

Alvaro Ayala Ruiz^*, Miguel A. Cruz Morales^*, Felipe M. Camarillo^**,J. Alfonso López Jiménez^*, Felipe Lugo Ramírez^*

^* Centro de diseño Mecánico, Facultad de Ingeniería UNAM, Circuito exterior, Talleres de Ingeniería Mecánica, CU. México, D.F.

E-mail: alvaro@limac.fi-c.unam.mx.

^** Médico adscrito.- Hospital General de México, Servicio de Ortopedia, Pabellón 106., Dr. Balmis 168, Col. Doctores, CP 06726.

This essay is part of an integral spinal analysis (lumbar area) applying the finite element methodology. The software used in Patología lumbar, is NISA DISPLAY III. The objective is understand the spinal behavior and be able to redesign the pedicle screw fit which fail when certain weight condition is apply.

Keywords: Elemento finito, Modelado, Análisis , Columna vertebral, Análisis Plano.

COB1103 DISTRIBUIÇÃO DE PRESSÃO NA VOLUTA DE UMa BOMBA CENTRÍFUGA UTILIZADA EM BYPASS CARDIOPULMONAR COM OXIGENADOR DE MEMBRANA/VOLUTE PRESSURE DISTRIBUTIONS OF A CENTRIFUGAL PUMP WHEN USED IN CARDIOPULMONARY BYPASS WITH EXTRACORPOREAL MEMBRANE OXYGENATION

MAZZA, Ricardo A. e ROSA, Eugênio S.

mazza@fem.unicamp.br e rosa@fem.unicamp.br - Cx.Postal 6122 - UNICAMP/FEM/DE - 13081-970 - Campinas - SP - Brasil

Vanless centrifugal blood pump such as Bio-pump has been designed to be used as a ventricular assist device (VAD). Due to the positive results, specially the reported low blood damage, its use has been extend to cardiopulmonary bypass (CPB). Under an engineering point of view, CPB requires a higher operational pressure level due to the use of a membrane oxygenator and arterial filters in the blood circuit. Despite of the successful results in VAD or CPB applications some deficiencies were reported. The long term use in VAD, without pump replacement, is not recommended due to possibility of seal leakage between casing and pump base. Also, for CPB applications has been reported blood damage levels comparable to the ones when roller pumps are employed. In both cases one may associate these phenomena to a non-uniform pressure distribution along the pump volute. This work addresses to the measurements of the pressure distribution along the pump volute with an in vitro analog circuit of CPB. The working fluid was water and the measured pressure drop, flow rate and rotational speed were converted to the values correspondent to the measurements done with a blood analogue fluid by using of the similarity principle.

Keywords: Centrifugal Pump; Blood Pump; Vanless Pump; Volute; Pressure Measurements

COB1131 A THERMOREGULATORY MODEL OF THE HUMAN BODY: EXPOSURE TO HOT ENVIRONMENT

Maurício Silva Ferreira & Jurandir Itizo Yanagihara

Departamento de Engenharia Mecânica, Escola Politécnica - USP

Av. Prof. Mello Moraes, 2231 - São Paulo - SP - CEP 05508-900 - SP E-mail: Jiyanagi@usp.br

A transient mathematical model for the human heat transfer system has been developed. It is based on a single cylinder, representing the body, with concentric annular layers: core, muscle, fat and skin. It includes metabolic heat generation, conduction of heat in tissue, convection of heat by flowing blood, heat transfer by radiation, convection and evaporation at the surface and loss of heat through the respiratory tract. The control system has two inputs: the mean temperatures from skin and core. Output variables are: the skin blood flow (vasomotor response) and the sweat rate (sudomotor response). The model can be used to simulate body’s response to a rise in ambient temperature beyond initial value or to a sudden exposure to solar radiation. The results were compared to data in the literature and showed good agreement. The model with some modifications can be used in thermal comfort applications.

Keywords: Temperature regulation, thermoregulation, mathematical model, thermal comfort / Regulação da temperatura, termorregulação, modelos matemáticos, conforto térmico.

COB1264 DETERMINAÇÃO EXPERIMENTAL DO MÓDULO DE ELASTICIDADE DA TÍBIA HUMANA ATRAVÉS DO DMTA

Antônio Carlos Shimano¹ , Mario Francisco Mucheroni² & Sebastião Vicente Carnevarolo Jr.³

1 Lab. de Bioengenharia da Faculdade de Medicina de Ribeirão Preto - USP

2 Dep. de Eng. Mecânica da Escola de Engenharia de São Carlos - USP

3 Dep. de Materiais - Área de Polímeros - UFSCAR

In this study of the mechanical properties of bones, focused on human tibiae, it was obtained the axial dynamic Young's modulus. A large number of specimens from several locations and at different orientations were harvested from one fresh human tibia. The axial dynamic Young modulus was obtained directly from the Dynamic Mechanical Thermal Analysis (DMTA). Such tests are commonly used in polymers, and were performed isothermally at 36,5°C using three frequencies: 0,1 Hz, 1,0 Hz and 10,0 Hz.

Keywords: Bioengenharia, Ossos, Tíbia Humana, Ensaio Dinâmico, DMTA, Módulo de Elasticidade.

COB1265 ANÁLISE DINÂMICA EM TÍBIA HUMANA: SIMULAÇÕES E TESTES

EXPERIMENTAIS

Antônio Carlos Shimano¹ & Mario Francisco Mucheroni²

1 Lab. de Bioengenharia da Faculdade de Medicina de Ribeirão Preto - USP

2 Depto. de Eng. Mecânica da Escola de Engenharia de São Carlos - USP

A study on the theoretical and experimental determination of the mode shapes and natural frequencies of dry treated and wet fresh human tibiae is presented. Dynamic simulations are performed using the Finite Element Method. The experimental modal tests are performed using the hammer impact setup, well known in mechanical engineering applications. The four first frequencies and corresponding mode shapes were obtained. The results are compared and the differences are discussed.

Keywords: Bioengenharia, Ossos, Elementos Finitos, Análise Modal.

COB1269 MECHANICS OF FACIAL AGING

Fabiana R. Leta^1,4, Aura Conci^1,2, Djenane Pamplona³, Hans Weber⁴ & Ivo Pitanguy⁵

¹ Departamento de Engenharia Mecânica, ² Pós-Graduação em Computação, Aplicada e Automação - CAA, UFF - Universidade Federal Fluminense, CEP 10-240 Niterói, RJ, Brasil - E-mail: fabiana, aconci@caa.uff.br

³ Departamento de Engenharia Civil, ⁴ Departamento de Engenharia Mecânica, ⁵ Departamento de Cirurgia Plástica, Pontifícia Universidade Católica do Rio de Janeiro, CEP 22453-900 Rio de Janeiro, Brasil - E-mail: djenane@civ.puc-rio.br, hans@mec.puc-rio.br

This paper presents a model for face aging, that uses a warping technique to emulate the aging changes. The implemented process considers the age features of selected parts of a face such as the face outline and the shape of the lips. These age features were obtained by measuring the facial regions of women that have been photographed throughout their lives. We propose a new method to define the aging parameters based on mechanics analysis and than graphically represents the age effects.

Keywords: Facial aging, mechanics of aging, warping, biomechanic / envelhecimento facial, biomecânica, mecânica do envelhecimento.

COB1323 A 4-DIMENSIONAL MODEL OF THE HUMAN HEART

Edilberto Strauss

Universidade Federal Fluminense - UFF/CAA

Rua Passo da Pátria, 156 Bloco E Sala 350, CEP: 24210-240, Niterói-RJ, Brazil, e-mail: strauss@caa.uff.br

Peter Burger

Imperial College of London, 180 Queen's Gate, London - SW7 2BZ - UK, e-mail:pb@doc.ic.ac.uk

The development of a four-dimensional solid modeling system is described. The applied technique provides three-dimensional visualization and animation of the human heart during its activated phase (the cardiac cycle). The modeling procedure is based on medical data-images generated by a magnetic resonance (MR) scanner. The visualization of the moving heart is based on a new approach for modeling dynamic free form objects which is particularly suitable for animation. The animation procedure is done by a volumetric morphing technique described as topological merging.

Keyword: Heart Modelling, 4-Dimensional Modelling, Animation, Visualization, Dynamic Modelling.

COB1334 ENVELHECIMENTO FACIAL POR GRAVIDADE / THE ACTION OF GRAVITY ON FACIAL AGING

Djenane Pamplona, Hans I. Weber & Paula Calux

Departamento de Engenharia Civil, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marquês de São Vicente, 225 - Gávea

CEP 22453-900 - Rio de Janeiro, RJ -Brasil - E-mail: djenane@civ.puc-rio.br.

From the photos of the American astronaut Shannon Lucid, it could be observed that she looked much younger without the gravitational field acting on the muscles of her face. Facial aging is a biological phenomenon but the facial movement of the skin during aging is also due to mechanics. The present research is a first step in identifying the mechanical forces responsible for facial deformation owing to time. With the use of a Nonlinear Finite Elements formulation in a facial mask with the mechanical properties of the skin, it was possible to discuss the effects of gravity in the mechanics of facial aging. A strong correlation between the effects of gravity and the behavior of the aging parameters of our recent work was found.

Keywords: Envelhecimento, Biomembranas, Elemento Finito. / Aging, Biomembranes, Finite Elements.

COB1397 IMPLANTES METÁLICOS RECOBERTOS COM HIDROXIAPATITA/COATINGS OF THE HYDROXYAPATITE ON THE IMPLANTS METALS

Eliana Cristina da Silva Rigo⁽¹⁾ , Luci Cristina de Oliveira⁽¹⁾ , Luís Alberto dos Santos⁽¹⁾ , Raúl Garcia Carrodéguas⁽²⁾ & Anselmo Ortega Boschi⁽¹⁾

Departamento de Engenharia de Materiais - DEMa, Laboratório de Biocerâmicas - BioLab, Universidade Federal de São Carlos - UFSCAR - Rodovia Washington Luiz - Km 235 - CEP 13565-905 - São Carlos - S.P., e-mail: eliana@iris.ufscar.br⁽¹⁾

Centro de Biomateriais - Universidade de Havana - Havana - Cuba, e-mail: biomat@comuh.uh.cu⁽²⁾

Materials in current use as implants can be classified as bioinert, biotolerable, and bioactive depending on the nature of their interaction with the living tissues. Among the several materials employed in implantology metals deserve special attention because of their high mechanical strength. However, metals are biotolerable materials being not able to bind to bone. On the other hand, bioactive materials can form strong chemical bond with bone but fail under high mechanical loads. Hydroxyapatite is the main component of the bone mineral. It has been extensively studied as a bone graft material and its excellent bioactivity and osteoconductivity have been clearly established. However, hydroxyapatite grafting is only advisable in situations of low or only compressive loads because of its weakness. Numerous efforts have been made to combine the strength of metals and the biological properties of hydroxyapatite via coating procedures. Methods such as ion sputtering, plasma spray, sol-gel, electrolysis, and biomimetic procedures have been used.

In this work the authors present the above mentioned coating techniques and comment on their advantages and disadvantages. They also revise briefly the existing reports on hydroxyapatite coating on metals by the different methods.

Keywords: Hydroxyapatite, Coating, Bioceramics, Calcium phosphate. Recobrimento, Hidroxiapatita, Biocerâmicas, Fosfato de cálcio

COB1415 DESENVOLVIMENTO DE UM TORQUÍMETRO DE PRECISÃO PARA O ESTUDO DO DESEMPENHO DE IMPLANTES OSSEOINTEGRADOS / VELOPMENT OF A TORQUE GAUGE OF HIGH PRECISION TO THE STUDY OF THE PERFORMANCE ON IMPANTS OSSEOINTEGRATION

Eduardo Carlos Bianchi * , Marcelo de Almeida Souza Santos * , Ana Rita Rodrigues Bianchi

** , João Roberto Gonçalves *** & Darceny Zanetta Barbosa ****

* UNESP - FET - Bauru - Departamento de Engenharia Mecânica - Av. Eng. Luiz Edmundo

Carrijo Coube, S/N o ,17033-360 - Bauru - SP - E-mail: bianchi@bauru.unesp.br

** USP - Universidade de São Paulo - Bauru - Departamento de Materiais Dentários - Rua Al.

Octávio Pinheiro Brisola, 9-75, - 17043-101 - Bauru - SP

*** Faculdade de Odontologia de Araraquara - UNESP - Departamento de Clínica Infantil

**** Universidade de Uberlândia - Departamento de Cirurgia

This work show the development about a torque gauge of high precision to improvement of odontological research on osseointegration of dental implant. The results are exame from pratical analysis on obtained with the developed tool instrument.

Keywords: Torque gauge of high precision, odontological research, osseointegration of dental implant.

COB1416 DESENVOLVIMENTO DE UMA METODOLOGIA PARA A AVALIAÇÃO DO DESGASTE ABRASIVO DE RESINAS COMPOSTAS / DEVELOPMENT OF A METODOLOGY TO AVALIATION OF THE ABRASIVE WEAR OF COMPOSITE RESIN

Eduardo Carlos Bianchi^*, Antonio Carlos Pires Dias^*, Ana Rita Rodrigues Bianchi^**, César Antunes de Freitas^**

^* UNESP - FET - Bauru - Departamento de Engenharia Mecânica - Av. Eng. Luiz Edmundo Carrijo Coube, S/N^o ,17033-360 - Bauru - SP

E-mail: bianchi@bauru.unesp.br

^** USP - Universidade de São Paulo - Bauru - Departamento de Materiais Dentários - Rua Al. Octávio Pinheiro Brisola, 9-75, - 17043-101 -

Bauru - SP

This work intends to show a new method where there is a test stand watched by a computer. It can evaluate the wearing (in a quantity form) of the composite resin used in dentistc restoration.

Keywords: Desgaste de resinas dentárias, tribologia de resinas compostas, mecanismo de remoção de material

COB1470 ESTAÇÃO PARA AVALIAÇÃO IN VITRO DE OXIGENADORES E PERMUTADORES DE CALOR / STATION OF "IN VITRO" TESTS FOR OXYGENATORS AND HEAT EXCHANGERS.

Novello, W.P., Ferreira, M.M., Succi, R.., Pecorario, J. R.& Braile, D.M.

Divisão de Pesquisas e Publicações - Departamentos de P&D em Mecânica e Eletrônica da Braile Biomédica.

In spite of the great number of extracorporeal procedures performed in Brazil, a few places can evaluate the basic function parameters of gas exchangers (oxygenators) and heat exchangers. This paper describes the project, construction and utilization of a station of "in vitro" tests to be able to evaluate the oxygen transfer, heat transfer and pressure drop. It is composed by on line blood gas monitor, peristaltic pumps with control and indication of blood flow, gas blender, manometers, thermometers, magnetic water pump, water reservoir with temperature control, supports of test devices, flow meters and supports for Nitrogen, Carbon dioxide and oxygen cylinders. The project includes electric circuits from water temperature and flow meter management and hydraulic circuit for water circulation. The test circuits and the quantitative results of evaluations are presented in the blood membrane oxygenators and heat exchangers with different materials and designs. This station tests was able to quantify some of the main performance parameters of gas and heat exchangers with easible and safely.

Keywords: Extracorporeal circulation, oxygenators, gas exchangers and heat exchangers. Circulação extracorpórea, oxigenadores, trocadores de gases e trocadores de calor

COB1474 AN AUGMENTED ENDURANCE TEST WITH ELECTROMECHANICAL PULSATILE TOTAL ARTIFICIAL HEART (TAH)

Yukio Ohashi, Aron de Andrade, Kin-ichi Nakata, Jürgen Müller, Yukihiko Nosé.

Baylor College of Medicine, Department of Surgery, One Baylor Plaza, Houston, Texas 77030, USA - E-mail: yohashi@bcm.tmc.edu

A Total artificial heart (TAH) has been developed in the Department of Surgery at Baylor College of Medicine. This TAH successfully underwent a hydrodynamic study, hemolysis study and two acute implantations. Before initiating a preclinical study, the reliability of the device needs to be documented based on the durability of each component including the electrical parts through a long-term endurance study,

This TAH was submitted to a four-month running test with the most severe driving condition where a maximum dP/dt was chosen more than 15,000 mm Hg/sec that is almost six times higher than that of a normal driving condition. The pump was submersed into a water bath that was maintained at 37^O C. The TAH was driven in a LMA variable rate mode at 8 L/min outflow, 15 mm Hg preload, 100 mm Hg left afterload and 25 mm Hg right afterload. The outflow, pressures, temperature inside the TAH and electrical current were monitored.

Several stress concentrating portions were detected. The connection between the roller nut and support plate lies in one of the most stress concentrating portions, and a more reliable fixing procedure was required, A redesign was made in this portion to offer a durable connection. No malfunction of the actuator and controller was detected throughout the testing duration. The required electrical power was 14.7 ± 1.6 watts and the total efficiency was 12.6 ± 1,4 %. The temperature in the TAH was 45.9 ± 0.9^O C on the motor, and 37.8 ± 0.3^O C on the centerpiece.

Keywords: total artificial heart, durability, augmented endurance study, stress concentrating portion.

COB1475 AVALIAÇÃO "IN VITRO" DO ÍNDICE HEMOLÍTICO EM VENTRÍCULO ARTIFICIAL PULSÁTIL / IN VITRO EVALUATION OF THE HEMOLYSIS INDEX IN A PULSATILE VENTRICULAR ASSIST DEVICE

Sergio A. Hayashida, Maria de Lourdes L. Silva, Marina J. S. Maizato, Idágene A. Cestari & Adolfo A. Leirner

Divisão de Bioengenharia - InCor - HCFMUSP, CEP 05403-000 São Paulo, SP, Brasil - E-mail: biosergio@incor4.incor.usp.br

High biocompatibility and low hemolysis are important characteristics for allowing long term use of blood pumps. We present an improved system for testing the hemolysis produced by an implantable pulsatile ventricular assist device (VAD) presently under development at our laboratory. The system has two flexible blood chambers immersed in fluid filled reservoirs. The chambers are connected to VADs driven by a pneumatic actuator. The results obtained with fresh heparinized bovine blood in four experiments showed that this system has a low degree of contribution on total hemolysis produced and provides a reliable method to determine hemolytic performance of VADs.

Keywords: Ventricular assist device, hemolysis index, thrombogenicity, in vitro test. Dispositivo de assistência ventricular, índice de hemólise, trombogenicidade, teste in vitro.

COB1476 MÉTODO DE OBTENÇÃO DE UMA PRÓTESE EM SILICONE PARA TORACOSTOMIA / METHOD FOR PROSTHESIS PRODUCTION IN SILICONE FOR THORACOSTOMY

Helena T. T. Oyama, Marina J.S Maizato, Adolfo A. Leirner & Luis T. B. Filomeno*.

Divisão de Bioengenharia - InCor - HCFMUSP, Av. Dr. Enéas de Carvalho Aguiar,44 - Cerqueira César - São Paulo -CEP: 05403-000

E-mail: biohelena@incor4.incor.usp.br

*Divisão de Cirurgia Torácica e Cardiovascular - HC-FMUSP

This paper presents the design and construction of a thoracostomy silicone prosthesis. Its main utilization is in Clagett’s and modified Eloesser thoracostomies and for the treatment of chronic and post-pneumonectomy empyemas. The prosthesis designed consists of a silicone tube corrugated and with one internal and one external flange to avoid migration. It can be placed through 30 to 40 mm incision and resection of a segment of solely one rib, minimizing surgical trauma and resulting in a esthetically improved aspect, while maintaining adequate and continuous draining of the pleural space. Hitherto, the prosthesis was utilized in 20 patients subjected to thoracostomy with a follow up period of 11 to 312 days. The results obtained suggest that its utilization presents many advantages in comparison to the traditional method utilized.

Keywords: Chronic empyema, thoracostomy, thoracostomy prosthesis. / Empiema crônico, toracostomia, prótese de toracostomia.

COB1477 PRÓTESE VENTRICULAR IMPLANTÁVEL- PROJETO MECÂNICO / IMPLANTABLE VENTRICULAR PROSTHESIS-MECHANIC DESIGN

Marina J. S. Maizato, Milton S. Oshiro, Sérgio A. Hayashida, Maria L. Lopes, Eucydes F. Marques, Gina H. Hamamoto, *Cecília A. C. Zavaglia & Adolfo A. Leirner

Divisão de Bioengenharia do Instituto do Coração - HC FMUSP, Av. Dr. Enéas de Carvalho Aguiar, 44 - Cerqueira César - São Paulo(SP)- CEP: 05403-000, e.mail: biomarina@incor4.incor.usp.br

*Departamento de Engenharia Biomédica - UNICAMP

This paper describes the design of an implantable artificial ventricular assist device to support the heart as a bridge to heart transplantation, in patients with profound cardiac failure. The artificial ventricle presented has a free floating membrane, dividing two titanium carcass. The driving unit is pneumatic. Two silicone cannulae are used to conect the device to the patient’s heart (left ventricle apex to aorta). Each cannula is eqquiped with one bovine pericardium valve. A computer program (Microstation) was utilized to provide volumetric calculus, bidimensional and tridimensional visualization to optimize the design. The results show perspectives for clinical utilization.

Keywords: Artificial Ventricle, Mechanic Assist Circulation, Ventricular Assist Device, Artificial Organs, Artificial Implants, Temporary Assist Device. / Ventrículo Artificial, Assistência Circulatória Mecânica, Dispositivo de Assistência Ventricular, Órgão Artificial, Dispositivo de Assistência Temporária.

COB1479 APRESENTAÇÃO DE UM DISPOSITIVO PARA AVALIAÇÃO "IN VIVO" DE ADESIVOS ODONTOLÓGICOS EM ENSAIOS DE TRAÇÃO. /PRESENTATION OF A DEVICE TO EVALUATE DENTAL ADHESIVES "IN VIVO" BY TENSION TESTS.

Aparício Fiuza de Carvalho Dekon, Eduardo Carlos Bianchi, César Antunes de Freitas & Antonio Santa Rossa Neto

Departamento de Engenharia Mecânica, Faculdade de Engenharia e Tecnologia - UNESP

Rua Eng. Luis Edmundo Carrijo Coube s/n Fone : (014) 230 - 2111 , Ramal 148 - FAX : (014) 231-1718

Caixa Postal 473 E-mail : bianchi@bauru.unsp.br, CEP 17033 - 360 Bauru, São Paulo, Brasil

The purpose of this study is to present a device designed to quantify the force required to remove orthodontic brackets directly in the oral environment. Elastic deformation caused by tension are transformed in electrical resistance variations by strain gauges placed in load cells. Electrical signs generated during the moviment are amplified by an amplifying bridge and the variations registered in an oscillograph. A previous calibration with difinite weights allowed the identification of the force required for removing the brackets bonded on dental enamel. The device was used to verify the "in vivo" performance of two bonding systems. One of them, the Orthodontic Concise (3 M - Brazil) based in composite resin, is widely used in Orthodontics being available since several years. The other, Fuji Ortho LC (GC Corporation) an hybrid composite and glass ionomer adhesive, recently available. The results were mutually compared and analysed.

Keywords: Extensômetros, Adesão Ortodôntica, Força de Adesão / Strain gauges, Orthodontic bonding, Bond strength

COB1481 ÍNDICES DE HEMÓLISE E VISUALIZAÇÃO DO FLUXO NA "SPIRAL PUMP"(SP), UMA BOMBA CENTRÍFUGA DE SANGUE POR FUSO CÔNICO/INDEX OF HEMOLYSIS AND FLOW VIZUALIZATION ON THE "SPIRAL PUMP"(SP), A CENTRIFUGAL BLOOD PUMP USING A CONICAL SPINDLE

Aron J. P. Andrade, Cantídio M. Campos Neto, Vivian M. Escobar, José F. Biscegli

Departamento de Bioengenharia, Instituto "Dante Pazzanese" de Cardiologia

Av. Dr. Dante Pazzanese, 500, Ibirapuera, São Paulo, SP, Brasil, CEP: 04012-180

The Spiral Pump (SP) is a blood pump that utilizes the two well known centrifugal and axial pumping principles, simultaneously. The hydrodynamic performance of this pump was studied at several test conditions, using a closed circuit loop with plastic tubes and reservoir, filled with 500 ml of 37% glycerin-water solution. The results show that the SP has good pumping performance. The flow behavior was studied in the most important areas of the pump using a stroboscopic planar helium-neon laser light. Amberlite plastic particles (80 mesh) were used in suspension in the solution and were illuminated by the laser light during the pumping process. Several in vitro hemolysis tests were performed using bovine blood, simulating two pump conditions: as left ventricular assist device and as cardiopulmonary bypass.

Keywords: Centrifugal Pump, Blood Pump, Extracorporeal Circulation, Ventricular Assist Device, Hemolysis.

Bomba Centrífuga, Bomba de Sangue, Circulação Extracorpórea, Bomba de Assistência Ventricular, Hemólise

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