Biomedical subjects

Robert Puers

Publications and source records attributed to Robert Puers.

6 recordsLinked to original sources

PubMed2006

An inductive power link for a wireless endoscope.

An inductive link is presented that can handle freedom of motion. The envisaged application is to power a wireless camera capsule used for non-invasive visual inspection of the small bowel. Up to 150 mW of usable dc power can be delivered to the capsule for the entire duration of its travel along the gastric track. The outer dimensions of the power receiver compartment inside the capsule are Ø 10 mmx13 mm. The power efficiency of the link is measured to be 1% under worst-case geometrical conditions. The issue of patient's health and safety regarding exposure to the electromagnetic field is addressed. To this purpose, an experimental method is applied to predict specific absorption rates. Conversely, the effect of biological tissue on link performance and practical workability is evaluated as well. Electric shielding of the transmitter coil is applied to reduce biological tissue interaction. In this way, appliance on a living subject is made both safe and practically feasible.

Capsule Endoscopes↗

PubMed2006

Implantation of an RFID-tag into human molars to reduce hard forensic identification labor. Part I: working principle.

Recently the tsunami disaster, the London bombings and the landfall of hurricane Katrina demonstrated once more the need for an accurate, quick and easy to handle identification system. The implantation of a radio frequency identification (RFID) tag into a human tooth and the read-out of its information may give an answer to this problem. A description is given of the modification of an existing RFID-tag that was made for veterinary use. This modified system was implanted in human molars using directly bonded resin composites. A protocol for tooth preparation and tag implantation was developed. A study of tag read-out patterns, revealed their accurate read-out distance range, the optimal site of RFID-tag implantation, assemblage of its components, and dimensions of the primary coil. It was found that disassembling the commercial RFID-tags was practically feasible and resulted in a properly working set-up. Further research is needed to optimize the design and the stability of RFID-tags for human identification purposes.

Disasters↗

PubMed2006

Implantation of an RFID-tag into human molars to reduce hard forensic identification labor. Part 2: physical properties.

Modifying and implanting existing RFID-tags into extracted human molars was described previously [P. Thevissen, G. Poelman, B. Puers, M. De Cooman, G. Willems, Implantation of RFID-tag into human molars to reduce hard forensic identification labor. Part 1. Working principle, Forensic Sci. Int. 156 (2006)]. Maximal vertical occlusal load during which the implanted RFID-tags remain active was evaluated in vitro. The temperature dependency of the implanted RFID-tags was studied on the extracted teeth to find out the maximal obtainable temperature before failure and a test with embedded thermistors to verify temperature distributions. The maximal working temperature of the implanted RFID-tags was revealed and gave indications for the set-up of measuring intra oral and intra tooth temperature during the cremation of a human body. Fatigue was induced on the implanted teeth by thermocycling. The results of this investigation showed the need of putting an extra insulating layer around the modified tags before implantation. The different in vitro tests indicated that the implanted RFID-tags can support certain oral and forensic circumstances.

Disasters↗

PubMed2004

A repeated sampling bone chamber methodology for the evaluation of tissue differentiation and bone adaptation around titanium implants under controlled mechanical conditions.

A repeated sampling bone chamber methodology was developed for the study of the influence of the mechanical environment on skeletal tissue differentiation and bone adaptation around titanium implants. Via perforations, bone grows into the implanted outer bone chamber, containing an inner bone chamber with a central test implant. An actuator--easily mounted on the outer bone chamber--allows a controlled mechanical stimulation of the test implant. After each experiment, the inner bone chamber--with its content--can be harvested and analysed. A new inner bone chamber with a central implant can be inserted consecutively in the outer bone chamber and a new experiment can start. Pilot studies led to a reliable surgical protocol and showed the applicability of the methodology, offering the possibility to study skeletal tissue differentiation and adaptation around implants under well-controlled mechanical conditions, and this protected from external loading. Repeated sampling of the bone chamber allows conducting several experiments within the same animal at the same site, thereby excluding subject- and site-dependent variability and reducing the amount of experimental animals.

Adaptation, Physiological↗

PubMed2004

Implant design and interface force transfer. A photoelastic and strain-gauge analysis.

OBJECTIVES: To compare stress and strain magnitudes of butt-joint and internal-cone oral implants in a bone simulant. MATERIAL AND METHODS: Photoelastic and strain-gauged models of solitary Brånemark, ITI and Astra Tech implants were obtained. Vertical and 20 degrees oblique forces of 100 and 150 N were applied on the abutments in separate load cases. Isochromatic fringe patterns around implants were observed and photographed in the field of a polariscope. Strain-gauge measurements were performed and principal strains induced around implants were calculated. RESULTS: Isochromatic fringe orders of all designs were similar under both loading conditions (P>0.05). Strains around Brånemark implants were lower than around Astra Tech and ITI implants, particularly under vertical loads. The latter implants had similar strain magnitudes (P>0.05), although strains around the conical Astra Tech implant were lower under vertical load. CONCLUSIONS: Butt-joint and internal-cone oral implants have similar force distribution characteristics. The implant-abutment mating design is not a decisive factor affecting stress and strain magnitudes in a bone simulant.

Biomechanical Phenomena↗

PubMed2004

Smart textiles.

After technical textiles and functional textiles, also smart textiles came into force a few years ago. The term 'smart textiles' covers a broad range. The application possibilities are only limited by our imagination and creativity. In this presentation, it is further explored what smart textiles precisely mean. In a second part, an analysis is made of the possibilities, the state of affairs and the needs for further research.

Computer Communication Networks↗