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PubMed1988

Clinical engineering in a downsizing environment.

Hospitals are currently facing cost-cutting pressures. To meet the challenge, some hospitals have downsized by reducing costs and by promoting new lines of business. In this environment, clinical engineers may need a proactive strategy to maintain the integrity of their service, demonstrate its value, and develop new business opportunities including shared-service maintenance, technology assessment, microcomputer applications, and training.

Biomedical Engineering↗
PubMedDate not supplied

A new model to estimate the appropriate staff for a clinical engineering department.

This study points out that the Clinical Engineering Department (CED) can provide expertise for the improvement of healthcare services if the size of the CED is appropriately determined; that is when the number of engineers, technicians and administrative staff is suitable for the activities that they are intended to carry out and for the amount of equipment they must manage. The paper presents a simple and flexible model where the staff is estimated according to the activities that need to be carried out by the CED and according to the amount of biomedical equipment being managed. Several examples of application and comparisons with the results provided by other models are reported and discussed.

Biomedical Engineering↗
PubMed2005

Porous-conductive chitosan scaffolds for tissue engineering II. in vitro and in vivo degradation.

Porous-conductive chitosan scaffolds were fabricated by blending conductive polypyrrole (PPy) particles with chitosan solution and employing an improved phase separation method. In vitro and in vivo degradation behaviors of these scaffolds were investigated. In the case of in vitro degradation, an enzymatic degradation system was employed and lysozyme was used as a working enzyme. Meanwhile, the degradation products of scaffolds, glucosamine and N-acetyl-glucosamine, were also analyzed with a HPLC method. In vivo degradation of scaffolds was performed by subcutaneously implanting these scaffolds in rat for pre-scheduled time intervals. In the both cases, the weight-loss of scaffolds was monitored during the whole degradation process for evaluating the degradation of scaffolds. The changes in conductivity of scaffolds afterin vitro or in vivo degradation were also measured using a four-point technique. It was observed that the pore parameters of scaffolds themselves could significantly influence the degradation behaviors of scaffolds but the PPy content in the scaffolds seemed not to impart its effect to the degradation of scaffolds. Degradation dynamics of scaffolds and conductivity measurements indicated that these scaffolds shown fairly different behaviors in their in vitro and in vivo degradation process. According to the results obtained from in vitro and in vivo degradation of scaffolds and based on some requirements of practical tissue engineering application, it was suggested that the PPy content in the scaffold should be slightly higher than 3 wt.% but lower than 6 wt.%.

Animals↗
PubMed2006

Enhancement of spin coherence using Q-factor engineering in semiconductor microdisc lasers.

Semiconductor microcavities offer unique means of controlling light-matter interactions in confined geometries, resulting in a wide range of applications in optical communications and inspiring proposals for quantum information processing and computational schemes. Studies of spin dynamics in microcavities, a new and promising research field, have revealed effects such as polarization beats, stimulated spin scattering and giant Faraday rotation. Here, we study the electron spin dynamics in optically pumped GaAs microdisc lasers with quantum wells and interface-fluctuation quantum dots in the active region. In particular, we examine how the electron spin dynamics are modified by the stimulated emission in the discs, and observe an enhancement of the spin-coherence time when the optical excitation is in resonance with a high-quality (Q approximately 5,000) lasing mode. This resonant enhancement, contrary to expectations from the observed trend in the carrier-recombination time, is then manipulated by altering the cavity design and dimensions. In analogy with devices based on excitonic coherence, this ability to engineer coherent interactions between electron spins and photons may provide new pathways towards spin-dependent quantum optoelectronics.

Biomedical Engineering↗
PubMedDate not supplied

Ethical responsibilities of the clinical engineer.

Because of the growth of medical technology, Clinical Engineers have increased responsibilities in respect to this new technology and so to modern medicine itself. This results in a need to ensure that an ethical consciousness of responsibilities to patients, physicians, and institutions grows within Clinical Engineers as they move into evermore important roles within the health care system. Clinical Engineers must have clearly defined roles, as well as authority acknowledged and supported by other health care professionals. Most importantly, Clinical Engineers themselves must recognize the seriousness of their professional responsibilities as they contribute to the maintenance of equipment, use and design instrumentation, and fulfill roles in administration, management, and research. As members of the health care team, Clinical Engineers must be prepared to face ethical issues arising from defective or inadequate equipment, hazards and incidents, scarcity and resources, conflict of interest, confidentiality, clinical research, "truth-telling," and care of the terminally ill.

Biomedical Engineering↗
PubMed1979

Position of bioengineering education in Hungary.

Medical electronic equipment has been produced in Hungary since the early forties. Industrial production of bioengineering started only in 1957. At the same time the bioengineering section of the Scientific Society of Measurement and Automation was founded. This Section was instrumental in recognizing the necessity for and establishing a structured education programme in bioengineering which started in the Postgraduate Institute for Engineers within Budapest Technical University. Later this was incorporated in the programme of the Technical University as an optional subject. Today there is also a specialised engineering course at the Technical University. There are significant developments in the bioengineering education of physicians and medical students. This paper deals with the possibility of classification bioengineering devices which has proved useful in education in Hungary.

Biomedical Engineering↗
PubMed2000

Modulation of the mechanical properties of tissue engineered cartilage.

Cartilaginous constructs have been grown in vitro using chondrocytes, biodegradable polymer scaffolds, and tissue culture bioreactors. In the present work, we studied how the composition and mechanical properties of engineered cartilage can be modulated by the conditions and duration of in vitro cultivation, using three different environments: static flasks, mixed flasks, and rotating vessels. After 4-6 weeks, static culture yielded small and fragile constructs, while turbulent flow in mixed flasks induced the formation of an outer fibrous capsule; both environments resulted in constructs with poor mechanical properties. The constructs that were cultured freely suspended in a dynamic laminar flow field in rotating vessels had the highest fractions of glycosaminoglycans and collagen (respectively 75% and 39% of levels measured in native cartilage), and the best mechanical properties (equilibrium modulus, hydraulic permeability, dynamic stiffness, and streaming potential were all about 20% of values measured in native cartilage). Chondrocytes in cartilaginous constructs remained metabolically active and phenotypically stable over prolonged cultivation in rotating bioreactors. The wet weight fraction of glycosaminoglycans and equilibrium modulus of 7 month constructs reached or exceeded the corresponding values measured from freshly explanted native cartilage. Taken together, these findings suggest that functional equivalents of native cartilage can be engineered by optimizing the hydrodynamic conditions in tissue culture bioreactors and the duration of tissue cultivation.

Animals↗
PubMed1995

Engineering principles of mechanical stimulation of the middle ear.

This article presents the transducer principles of possible middle ear hearing devices with their characteristics and selection considerations summarized. The frequency response and the needed force and displacement at the ossicular chain sites were measured to determine approximately the system requirements and design considerations. The power required to vibrate the ossicular chain is estimated to be of the order of 0.1 watt, which is three orders of magnitude smaller than the power consumption of devices being developed in various laboratories. Careful engineering design and evaluation is needed. A design example of the transducer used with a partially implantable, noncontact electromagnetic hearing device is presented in this article with laboratory evaluation results.

Biomedical Engineering↗
PubMed2004

Cognitive and usability engineering methods for the evaluation of clinical information systems.

Increasingly healthcare policy and decision makers are demanding evidence to justify investments in health information systems. This demand requires an adequate evaluation of these systems. A wide variety of approaches and methodologies have been applied in assessing the impact of information systems in health care, ranging from controlled clinical trials to use of questionnaires and interviews with users. In this paper we describe methodological approaches which we have applied and refined for the past 10 years for the evaluation of health information systems. The approaches are strongly rooted in theories and methods from cognitive science and the emerging field of usability engineering. The focus is on assessing human computer interaction and in particular, the usability of computer systems in both laboratory and naturalistic settings. The methods described can be a part of the formative evaluation of systems during their iterative development, and can also complement more traditional assessment methods used in summative system evaluation of completed systems. The paper provides a review of the general area of systems evaluation with the motivation and rationale for methodological approaches underlying usability engineering and cognitive task analysis as applied to health information systems. This is followed by a detailed description of the methods we have applied in a variety of settings in conducting usability testing and usability inspection of systems such as computer-based patient records. Emerging trends in the evaluation of complex information systems are discussed.

Biomedical Engineering↗
PubMed1992

Collagen engineering for biomaterial use.

Collagen is a typical biological macromolecule having been utilized for a long period of time as a material like cellulose. However, its application is becoming comprehensive, ranging from classical applications such as the leather, gelatine and food industries to the current one, namely, biomaterial and biotechnological uses. The diversification of collagen applications was enhanced by two factors, the accumulation of the scientific knowledge that permitted proper engineering of collagen for a biomaterial use, and the demand for new biomaterials with characteristic biological properties including interaction with cells. The collagen engineering described in this paper is designed for biomaterial use, based on the fundamental chemical and biological properties of collagen; however, it would be useful also for other applications apart from biomaterials.

Biocompatible Materials↗
PubMed2005

Nanotechnology approaches for the regeneration and neuroprotection of the central nervous system.

Nanotechnology is the science and engineering concerned with the design, synthesis, and characterization of materials and devices that have a functional organization in at least 1 dimension on the nanometer (ie, one-billionth of a meter) scale. The ability to manipulate and control engineered self-assembling (ie, self-organizing) substrates at these scales produces macroscopic physical and/or chemical properties in the bulk material not possessed by the constituent building block molecules alone. This in turn results in a degree of functional integration between the engineered substrates and cellular or physiological systems not previously attainable. Applied nanotechnology aimed at the regeneration and neuroprotection of the central nervous system (CNS) will significantly benefit from basic nanotechnology research conducted in parallel with advances in cell biology, neurophysiology, and neuropathology. Ultimately the goal is to develop novel technologies that directly or indirectly aid in providing neuroprotection and/or a permissive environment and active signaling cues for guided axon growth. In some cases, it is expected that the neurosurgeon will be required to administer these substrates to the patient. As such, in order for nanotechnology applications directed toward neurological disorders to develop to their fullest potential, it will be important for neuroscientists, neurosurgeons, and neurologists to participate and contribute to the scientific process alongside physical science and engineering colleagues. This review will focus on emerging clinical applications aimed at the regeneration and neuroprotection of the injured CNS, and discuss other platform technologies that have a significant potential for being adapted for clinical neuroscience applications.

Biomedical Engineering↗
PubMed2006

Biomimetic approaches to protein and gene delivery for tissue regeneration.

Novel therapeutic strategies that promote wound healing seek to mimic the response of the body to wounding, to regenerate rather than repair injured tissues. Many synthetic or natural biomaterials have been developed for this purpose and are used to deliver wound therapeutics in a controlled manner that prevents unwanted and potentially harmful side-effects. Here, we review the natural and synthetic biomaterials that have been developed for protein and gene delivery to enhance tissue regeneration. Particular emphasis is placed on novel biomimetic materials that respond to environmental stimuli or release their cargo according to cellular demand. Engineering biomaterials to release therapeutic agents in response to physiologic signals mimics the natural healing process and can promote faster tissue regeneration and reduce scarring in severe acute or chronic wounds.

Animals↗
PubMed2002

Modeling and simulation: tools for metabolic engineering.

Mathematical modeling is one of the key methodologies of metabolic engineering. Based on a given metabolic model different computational tools for the simulation, data evaluation, systems analysis, prediction, design and optimization of metabolic systems have been developed. The currently used metabolic modeling approaches can be subdivided into structural models, stoichiometric models, carbon flux models, stationary and nonstationary mechanistic models and models with gene regulation. However, the power of a model strongly depends on its basic modeling assumptions, the simplifications made and the data sources used. Model validation turns out to be particularly difficult for metabolic systems. The different modeling approaches are critically reviewed with respect to their potential and benefits for the metabolic engineering cycle. Several tools that have emerged from the different modeling approaches including structural pathway synthesis, stoichiometric pathway analysis, metabolic flux analysis, metabolic control analysis, optimization of regulatory architectures and the evaluation of rapid sampling experiments are discussed.

Biomedical Engineering↗
PubMed2001

Tissue-engineered mucosa graft for reconstruction of the intraoral lining after freeing of the tongue: a clinical and immunohistologic study.

PURPOSE: This article describes the use of tissue-engineered mucosal grafts instead of split-thickness skin grafts after freeing of the tongue in patients who had previous resection of an oral squamous cell carcinoma and initial primary wound closure. PATIENTS AND METHODS: Tissue-engineered mucosal grafts, up to 75 cm2 in size, were cultured from biopsy specimens of the hard palate in 6 patients, starting 3 to 4 weeks before the operation. After freeing of the tongue, the engineered mucosa was implanted on the wound surface by using vaseline gauze as carrier and fixed with an intraoral gauze wound dressing. RESULTS: A good glossoalveolar sulcus was formed in 5 patients, resulting in good mobility of the tongue and a satisfactory denture-bearing surface. In 1 patient, there was a disturbance of wound healing, leading to severe shrinkage of the glossoalveolar sulcus and very limited improvement in tongue mobility. Preoperative bromodeoxyuridine (BrdU) labeling of the graft and postoperative immunohistochemical staining of biopsy specimens from the grafted areas with anti-BrdU showed that the cultured cells are integrated into the newly formed mucosal epithelium. Postoperative histologic investigations showed a differentiation process in the grafted mucosal epithelium, with a change in the expression of cytokeratins. At 6 months postoperatively, the typical pattern of normal nongrafted mucosa was regained. CONCLUSIONS: This investigation provides evidence that tissue-engineered mucosal cells can serve as a graft for large intraoral wounds. Complete intraoral lining is quickly reestablished, and normal epithelial differentiation is seen in the graft area within a 6-month postoperative period.

Adult↗
PubMed2000

Practical illustrations in tissue engineering: surgical considerations relevant to the implantation of osteoinductive devices.

This paper provides practical illustrations in the use of osteoinductive devices (biomaterial carriers coupled with osteoinductive morphogens) for bone tissue engineering. We discuss the considerations relative to the implantation of these devices that may induce tissues that are located outside the boundaries of the osteoinductive device as well as outside boundaries of the normal skeletal envelope. Five reports of osteoinductive devices generating such tissues are reviewed. Histologic and radiographic data from a sixth example are presented and compared with histologic and radiographic findings typical of two varieties of myositis ossificans. A theory is advanced that osteoinductive implants may induce ectopic tissues that resemble fibro-osseous pathologies. Finally characteristics of tissue-engineered bone graft substitutes that may contribute to development of these pathologies and device characteristics that may obviate these ectopic tissues are considered.

Animals↗