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PubMed2003

[An approach to the cardiovascular technology through the interdisciplinarity: a Latin American necessity].

The progresses obtained in the cardiovascular medicine during the last years come to transform the content and the practice of the profession. These advances are consequence of the contribution of basic disciplines like the physics, the chemistry and sciences of the information. Thanks to those disciplines, which establish narrow bonds to each other, appear in the language the transdisciplinary sciences like the biophysics and the biochemistry, an approach between biological and the inorganic thing; as well as the interdisciplinary techniques of the biomedical engineering, whose work move in the medical surroundings using tools of engineering, like the bioinstrumentation, the biomechanics, the bioelectronic and the biomaterials. With these set of tools, it has been possible to extend the diagnoses methods as well as the therapeutic ones in the cardiovascular area, improving substantially the quality of life of the patients. As a result of it, the doctor-engineer encounter becomes transcendent, increasing the dialogue between both disciplines; in what must take part professionals of wide diversity of areas: cardiologists, cardiovascular surgeons, mechanical engineers, electronics engineers, industrial systems engineers, physicists, designers, among others; contributing each one in its field of the knowledge, but coming together towards a same axis of action.

Biochemical Phenomena↗
PubMed1989

Holographic interferometry.

Since its inception three decades ago, holographic interferometry has proven to be a powerful nondestructive testing technique for the measurement of displacement and its derivatives. It is a whole-field, noncontact method which requires the use of a hologram to record three-dimensional information about the surface of an object. After a stress is applied to the object, its new surface geometry is compared with the previously recorded state. Changes of the surface of the object, which are manifest as a series of interference fringes superimposed on the image of the object, can be observed statically or in real time to reveal the displacement. Current state-of-the-art techniques such as heterodyne and digital phase shifting interferometry, which have extended the resolution of holographic interferometry far beyond fringe counting, are reviewed. Particular emphasis is placed upon applications in biomedical engineering and medicine, although potentially applicable techniques from other disciplines are examined. The paper is broken into two main parts. In the first part, the scope and potential limitations of this branch of metrology are presented. In the second part, a review of applications in biomedical engineering is presented. The references cited in the first section are the seminal papers in the field. The applications section, which relies upon the results of the first section, presents a critical review of the literature by analyzing the results of a few representative studies.

Fiber Optic Technology↗
PubMed2006

Confessions of a serial entrepreneur: a conversation with Alfred E. Mann. Interview by Molly Joel Coye.

In this wide-ranging interview, Alfred Mann describes the activities of several medical technology enterprises with which he is engaged. Several of them are companies that he formed; one is a nonprofit foundation, the Alfred E. Mann Foundation for Biomedical Engineering, founded to establish research-oriented institutes on a dozen university campuses and support their work in developing marketable innovations. Mann discusses the need to consider the cost implications of technology, in the context of U.S. health system reform, and describes several important innovations that have emerged from his companies over the years.

Biomedical Engineering↗
PubMedDate not supplied

1992 ALZA Distinguished Lecture: bioengineering and vascular biology.

The vascular system is naturally dynamic; fluid mechanics and mass transfer are closely integrated with blood and vascular cell function. We are beginning to understand how local wall shear stress and strain modulate endothelial cell metabolism at the gene level. This knowledge may help explain the focal nature of many vascular pathologies, including atherosclerosis. Understanding mechanical control of gene regulation at the level of specific promoter elements and transcription factors involved will lead to development of novel constructs for localized delivery of specific gene products in regions of high or low shear stress or strain in the vascular system. In addition, recent research has shown how local fluid mechanics can alter receptor specificity in cell-to-cell and cell-to-matrix protein adhesion and aggregation. Knowledge of the specific molecular sequences involved in cell-to-cell recognition will allow development of targeted therapeutics, with applications in thrombosis, inflammation, cancer metastasis, and sickle-cell anemia. Bioengineers are uniquely qualified to be leaders in this field, because advances require a synthesis of cell and molecular biology with systems analysis, transport phenomena, and quantitative modeling. Rapid progress in tissue engineering applications will require this new kind of biomedical engineer, which represents both a challenge and an opportunity for our profession.

Biomedical Engineering↗
PubMed2001

THOMAS MCMAHON: A Dedication in Memoriam.

Thomas A. McMahon (1943-1999) was a pioneer in the field of biomechanics. He made primary contributions to our understanding of terrestrial locomotion, allometry and scaling, cardiac assist devices, orthopedic biomechanics, and a number of other areas. His work was frequently characterized by the use of simple mathematical models to explain seemingly complex phenomena. He also validated these models through creative experimentation. McMahon was a successful inventor and also published three well-received novels. He was raised in Lexington, Massachussetts, attended Cornell University as an undergraduate, and earned a PhD at MIT. From 1970 until his death, he was a member of the faculty of Harvard University, where he taught biomedical engineering. He is fondly remembered as a warm and gentle colleague and an exemplary mentor to his students.

Journal Article↗
PubMed2005

Determining rigid body transformation parameters from ill-conditioned spatial marker co-ordinates.

The three-dimensional location of a body-fixed axis system is described by position and orientation parameters that can be calculated knowing local and global coordinates of three or more body-fixed markers. However, marker distribution can become ill-conditioned when marker placement is symmetrical with respect to the mean of the markers. As symmetry and ill-conditioning increases, random errors in marker locations can affect the stability of orientation parameters as a result of the mathematical approach adopted. The present study investigates the methods of Veldpaus et al. [1988; Journal of Biomechanics 21, 45], Challis [1995; Biomechanics 28, 733] and Andriacchi et al. [1998; Journal of Biomedical Engineering 120, 743] for obtaining segment orientation parameters when segment markers ranged from well-defined to highly ill-conditioned depending on the symmetry of segment markers. A novel fourth approach is also presented that enabled comparisons of the root mean square error of reconstructed marker coordinates to verify that an optimal solution was obtained. No single method produced optimal results for all axis orientation parameters when reconstructing movement trials. The best performed was the method of Veldpaus et al. [1988; Journal of Biomechanics 21, 45] based on consistent results and ease of implementation. The fourth approach presented provided a reliable method in all but the highly ill-conditioned markers, however implementation was computationally difficult. The method of Challis [1995; Biomechanics 28, 733] was only suited to well-conditioned marker sets which avoided markers lying in a single plane with symmetries in marker distribution relative to the mean. The method of Andriacchi et al. [1998; Journal of Biomedical Engineering 120, 743] produced, at best, orientation parameters that approximated the results obtained by least squares methods.

Algorithms↗
PubMed2005

Helical rosette nanotubes with tunable stability and hierarchy.

The design of nanostructured materials with tunable dimensions and properties that maintain their structural integrity under physiological conditions is a major challenge in biomedical engineering and nanomedicine. Helical rosette nanotubes (HRN) are a new class of materials produced through a hierarchical self-assembly process of low molecular weight synthetic organic modules in water. Here, we describe a synthetic strategy to tune their stability and hierarchy by preorganization of the self-assembling units, control of net charge per unit of nanotube surface area, amphiphilicity, and number of H-bonds per self-assembling module, and through peripheral steric (de)compression. Using these criteria, HRNs with tunable stability and hierarchical architecture were produced from self-assembling modules that (a) persist as individual molecules in solution, (b) self-assemble into HRN but denature at high temperature (<85 degrees C), (c) self-assemble into HRN whose structural integrity persists even in boiling water (>95 degrees C), and (d) self-assemble into well-dispersed short nanotubes, long nanotubes, ribbons, or superhelices. Given the biocompatibility, synthetic accessibility, and chemical and physical tunability of these materials, numerous applications in biomedical engineering, materials science, and nanoscience and technology are envisioned.

Journal Article↗
PubMed2004

Formulation of photon diffusion from spherical bioluminescent sources in an infinite homogeneous medium.

BACKGROUND: The bioluminescent enzyme firefly luciferase (Luc) or variants of green fluorescent protein (GFP) in transformed cells can be effectively used to reveal molecular and cellular features of neoplasia in vivo. Tumor cell growth and regression in response to various therapies can be evaluated by using bioluminescent imaging. In bioluminescent imaging, light propagates in highly scattering tissue, and the diffusion approximation is sufficiently accurate to predict the imaging signal around the biological tissue. The numerical solutions to the diffusion equation take large amounts of computational time, and the studies for its analytic solutions have attracted more attention in biomedical engineering applications. METHODS: Biological tissue is a turbid medium that both scatters and absorbs photons. An accurate model for the propagation of photons through tissue can be adopted from transport theory, and its diffusion approximation is applied to predict the imaging signal around the biological tissue. The solution to the diffusion equation is formulated by the convolution between its Green's function and source term. The formulation of photon diffusion from spherical bioluminescent sources in an infinite homogeneous medium can be obtained to accelerate the forward simulation of bioluminescent phenomena. RESULTS: The closed form solutions have been derived for the time-dependent diffusion equation and the steady-state diffusion equation with solid and hollow spherical sources in a homogeneous medium, respectively. Meanwhile, the relationship between solutions with a solid sphere source and ones with a surface sphere source is obtained. CONCLUSION: We have formulated solutions for the diffusion equation with solid and hollow spherical sources in an infinite homogeneous medium. These solutions have been verified by Monte Carlo simulation for use in biomedical optical imaging studies. The closed form solution is highly accurate and more computationally efficient in biomedical engineering applications. By using our analytic solutions for spherical sources, we can better predict bioluminescent signals and better understand both the potential for, and the limitations of, bioluminescent tomography in an idealized case. The formulas are particularly valuable for furthering the development of bioluminescent tomography.

Computer Simulation↗
PubMedDate not supplied

Education of clinical engineers in the 1990s.

This paper presents definitions of the terms bioengineering, biomedical engineering and clinical engineering. These definitions lead to the conclusion that clinical engineers must be individuals with at least a four-year bachelor's degree in an engineering specialty who are also well versed in the design, modification and testing of medical instrumentation. Educational programs for clinical engineers in the 1990s must be based upon clear definitions of these professionals' roles. Clinical engineering education should include direct professional experience obtained through internship programs similar to the program described here.

Biomedical Engineering↗
PubMed2004

The WEBD project: a research of new methodologies for a distant-learning 3D system prototype.

OBJECTIVES: To create and to spread a new interactive multimedia instrument, based upon virtual reality technologies, that allows both the running simulation of machines and equipment and the reproduction via Web of complex three-dimensional (3D) anatomical models such as the skull. METHODS: There were two main aspects of the project, one of design engineering and the other biomedical engineering, for the creation of "artificial" and anatomical objects. The former were made with 3D Studio Max R4 by Autodesk, San Rafael, CA, while the latter were created starting from real bones scanned with a CT system or a surface scanner and elaborated with different programs (3D Studio Max R4, Scenebuilder by Viewpoint, New York, NY and Spinfire by Actify, San Francisco, CA). The 3D models were to be integrated into web modules and had to respect file limits while preserving a sufficient definition. Two systems of evaluation were used, a questionnaire on a selected sample and an external evaluation by a different university. RESULTS: The Viewpoint format offers the best interactivity and size reduction (up to 96% from the original 3D model). The created modules included production of radiological images, rapid prototyping, and anatomy. The complete "3D Distant Learning Prototype" is available at www.webd.etsii.upm.es. CONCLUSIONS: The software currently available permits the construction of interactive modules. The verification on the selected sample and the evaluation by the University of Naples show that the structure is well organized and that the integration of the 3D models meets the requirements.

Computer Graphics↗
PubMed1998

Shape memory alloys for medical applications.

The shape memory alloys exhibit a number of remarkable properties, which open new possibilities in engineering and more specifically in biomedical engineering. The most important alloy used in biomedical applications is NiTi. This alloy combines the characteristics of the shape memory effect and superelasticity with excellent corrosion resistance, wear characteristics, mechanical properties and a good biocompatibility. These properties make it an ideal biological engineering material, especially in orthopaedic surgery and orthodontics. In this work the basis of the memory effect lies in the fact that the materials exhibiting such a property undergo a thermoelastic martensitic transformation. In order to understand even the most elementary engineering aspects of the shape memory effect it is necessary to review some basic principles of the formation and the characteristics of the martensitic phase. The different properties of shape memory, superelasticity, two-way shape memory, rubber-like behaviour and a high damping capacity are reviewed. Some applications proposed in recent years are described and classified according to different medical fields.

Alloys↗
PubMed2000

Ethical considerations for biomedical scientists and engineers: issues for the rank and file.

Biomedical science and engineering is inextricably linked with the fields of medicine and surgery. Yet, while physicians and surgeons, nurses, and other medical professionals receive instruction in ethics during their training and must abide by certain codes of ethics during their practice, those engaged in biomedical science and engineering typically receive no formal training in ethics. In fact, the little contact that many biomedical science and engineering professionals have with ethics occurs either when they participate in government-funded research or submit articles for publication in certain journals. Thus, there is a need for biomedical scientists and engineers as a group to become more aware of ethics. Moreover, recent advances in biomedical technology and the ever-increasing use of new devices virtually guarantee that biomedical science and engineering will become even more important in the future. Although they are rarely in direct contact with patients, biomedical scientists and engineers must become aware of ethics in order to be able to deal with the complex ethical issues that arise from our society's increasing reliance on biomedical technology. In this brief communication, the need for ethical awareness among workers in biomedical science and engineering is discussed in terms of certain conflicts that arise in the workaday world of the biomedical scientist in a complex, modern society. It is also recognized that inasmuch as workers in the many branches of bioengineering are not regulated like their counterparts in medicine and surgery, perhaps academic institutions and professional societies are best equipped to heighten ethical awareness among workers in this important field.

Authorship↗
PubMed2005

In memorium: Herman p. Schwan [1915-2005].

Herman P. Schwan [1915-2005] was a distinguished scientist and engineer, and a founding father of the field of biomedical engineering. A man of integrity, Schwan influenced the lives of many, including his wife and children, and his many students and colleagues. Active in science until nearly the end of his life, he will be very much missed by his family and many colleagues.

Biomedical Engineering↗
PubMed2006

Perspectives of gene therapy in stem cell tissue engineering.

Tissue engineering is an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain or improve tissue function. It is hoped that forming tissue de novo will overcome many problems in plastic surgery associated with such areas as wound healing and the immunogenicity of transplanted tissue that lead to dysfunctional repair. Gene therapy is the science of the transfer of genetic material into individuals for therapeutic purposes by altering cellular function or structure at the molecular level. Recently, tissue engineering has been used in conjunction with gene therapy as a hybrid approach. This combination of stem-cell-based tissue engineering with gene therapy has the potential to provide regenerative tissue cells within an environment of optimal regulatory protein expression and would have many benefits in various areas such as the transplantation of skin, cartilage or bone. The aim of this review is to outline tissue engineering and possible applications of gene therapy in the field of biomedical engineering as well as basic principles of gene therapy, vectors and gene delivery.

Animals↗
PubMed2006

Teaching cellular engineering.

Cellular engineering is one of the fastest growing subdisciplines in the field of Biomedical Engineering. It involves the application of engineering analysis to understand and control cellular behavior, with the ultimate objective of developing novel therapeutic or diagnostic approaches for the clinic or harnessing cellular function for commercial applications. Well-educated students in this area need strong foundational knowledge in engineering science, chemistry, and cell and molecular biology. In undergraduate curricula, the challenge is to include essential engineering skills plus appropriate levels of training in chemistry and biology while satisfying accreditation-mandated breadth in engineering training. At the graduate level, educators must accommodate students with diverse backgrounds and provide them with both a state-of-the-art understanding of the life sciences and the most advanced engineering skills. Engineering curricular content should include mechanics and materials, physical chemistry, transport phenomena, and control theory. Training from faculty with appointments and research programs in the life sciences is generally recommended, and additional life science content should also be integrated within the engineering curriculum. A capstone course in cellular engineering that includes opportunities for students to have hands-on experiences with state-of-the-art laboratory techniques is highly recommended.

Benchmarking↗
PubMedDate not supplied

Focus on: ORBIS International Flying Eye Hospital, Department of Technical Services.

The ORBIS International Flying Eye Hospital is dedicated to restoring sight to the blind through medical education programs in developing countries. The modification of a DC-10 aircraft to house a teaching hospital for ophthalmic surgery involved a variety of engineering challenges to satisfy standards for both hospital and aircraft safety. The Technical Services Department maintains all medical equipment on the aircraft, encountering situations not found in traditional clinical engineering departments. Technical education is also an important part of the ORBIS biomedical engineering program. Future plans include expansion of existing technical training efforts, as well as using technology to improve the medical education program as a whole.

Aircraft↗
PubMed2006

Regenerative inductive therapy based on DDS technology of protein and gene.

Recent development of biomedical engineering including biomaterials and drug delivery system (DDS) as well as basic biology and medicine has enabled cells to induce regeneration repairing of defective tissues as well as substitute the biological functions of damaged organs. For successful tissue regeneration, it is undoubtedly indispensable to give cells a local environment which allows cells to efficiently promote their proliferation and differentiation and consequently induce cell-based tissue regeneration. Tissue engineering is one of the biomedical forms to create this regeneration environment of cells. The tissue and organ repairing based on their regeneration induction has been realized by combining cells with the tissue engineering technology or methodology in a surgical or internally medical manner. This paper overviews the present status and future direction of tissue engineering for regenerative inductive therapy, briefly explaining the key technology of tissue engineering, especially DDS of growth factor and gene.

Animals↗
PubMedDate not supplied

[Distance learning using internet in the field of bioengineering].

The Leonardo da Vinci training programme supports innovative transnational initiatives for promoting the knowledge, aptitudes and skills necessary for successful integration into working life. Biomedical engineering is an emerging interdisciplinary field that contributes to understand, define and solve problems in biomedical technology within industrial and health service contexts. Paper presents a Leonardo da Vinci pilot-project called Web-based learning and training in the field of biomedical and design engineering (WEBD). This project has started on 2001. The WEBD project proposes to use advanced learning technologies to provide education in the www. Project uses interactive 3D graphics and virtual reality tools. The WEBD distance training permits users to experience and interact with a life-like model or environment, in safety and at convenient times, while providing a degree of control over the simulation that is usually not possible in the real-life situation.

Biomedical Engineering↗