Biomedical Engineering and Bioengineering Commons^™

The Crystallisation Of Glasses From The Ternary Caf2-Caal2si2o8-P2 O5 System, A. Clifford, R. G. Hill, Mark R. Towler, D. J. Wood

Chemical and Biochemical Engineering Faculty Research & Creative Works

A study of glasses from the ternary system CaF₂-CaAl₂Si₂O₈-P₂O₅ has been carried out. It has been shown that glasses with low phosphorus contents and high fluorite contents crystallise to fluorite. Fluorine reduces the glass transition temperature and is also required for the formation of fluorapatite (FAP). In the absence of fluorine in the glass no apatite phase is formed. Bulk nucleation of FAP is favoured for glasses with Ca:P ratios close to the apatite stoichiometry of 1.67 and with low crosslink densities. Thermal gravimetric analysis showed significant weight losses …

A Preliminary Comparison Of The Mechanical Properties Of Chemically Cured And Ultrasonically Cured Glass Ionomer Cements, Using Nano-Indentation Techniques, Mark R. Towler, A. J. Bushby, R. W. Billington, R. G. Hill

Chemical and Biochemical Engineering Faculty Research & Creative Works

There is a requirement for a dental cement with properties comparable or superior to conventional glass ionomer cements (GICs) but with the command set properties of the resin modified GICs. The objective of this work was to show that the application of ultrasound to conventional Fuji IX commercial glass ionomer cement imparts a command set, whilst improving the short-term surface mechanical properties. Nano-indentation techniques were employed to highlight the improvements in hardness and creep resistance imparted to the cement through the application of ultrasound. The instant set imparted by the application of ultrasound provides improved surface hardness and creep, particularly …

Novel Processing Of Hydroxyapatite-Zirconia Composites Using Nano-Sized Particles, Mark R. Towler, I. R. Gibson, S. M. Best

Chemical and Biochemical Engineering Faculty Research & Creative Works

A method to produce composites of hydroxyapatite (HA) with ZrO2 (Y-TZP) additions between 0 and 10 wt % at a low sinter temperature of 750 °C is presented. The method limits the amount of reaction between the HA and ZrO2. A ZrO2 loading level that would improve strength while limiting the decomposition of the HA is studied.

Effects Of Adding Sodium And Fluoride Ions To Glass Ionomer On Its Interactions With Sodium Fluoride Solution, R. W. Billington, P. C. Hadley, Mark R. Towler, G. J. Pearson, J. A. Williams

Chemical and Biochemical Engineering Faculty Research & Creative Works

This investigates the effects of the addition of Na and F ions to a glass ionomer cement in which those ions are not inherently present on its interactions with dilute (0.2%) NaF solution. Both the effect of the solution on the cement's surface morphology and the effect of the cement on the solution in terms of take up of Na⁺ and F^- and of change in pH are to be investigated. These results are to be compared to previous results obtained with glasses which contained both, one, or neither of the ions as components of their glasses. NaF …

The Influence Of Poly(Acrylic Acid) Molar Mass On The Properties Of Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Sinead Kenny, Robert G. Hill, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The influence of poly (acrylic acid) molar mass was investigated on cements formed from zinc oxide-apatite mixtures at three aging times: one, seven and 28 days. Cements based on both hydroxyapatite and fluorapatite were investigated. The compressive strength, un-notched fracture strength and fracture toughness increased markedly with poly (acrylic acid) molar mass. The fracture toughness and un-notched fracture strength increased with aging time for the two highest molar mass cements but decreased with time for the two lowest molar mass cements. The greater chain entanglement density present in the higher molar mass cements is thought to contribute significantly to the …

Optimization Of Insertion Holes And Anchor Design For Cylinder Shaped Toggle Type Suture Anchors, Adam Fedenia

Masters Theses

This research was performed to optimize insertion holes and anchor design for cylinder shaped toggle type suture anchors. Four types of anchors were investigated in terms of pull strength and design in acrylic plate and pig bone. They included small type A and B anchors and large type A and B anchors.

Pull strength trends suggest that the small type anchors behave similarly since their external dimensions are identical, with the exception of type A anchor having a hole running from one end of the cylinder to the other like a pipe. It was found that the suture would fail …

Fetal Heart Rate Detection With A Passive Acoustic Sensor System, Zongyao Zhou

Electrical & Computer Engineering Theses & Dissertations

Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones from noise contaminated signals obtained from passive acoustic sensors. A nonlinear Teager energy operator is utilized for detection of the fetal heart tone event. Autocorrelation and a parallel redundancy correction algorithm derives fetal heart rates. A real time monitoring system is described which records and plots the time history of both the fetal heart rate and the acoustic fetal heart signal. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a …

New In Vivo And In Vitro Techniques For Quantification Of Lateral Force Levels That Cause Implants To Fail : A Progress Report On Monkey Research, V. Leroy Leggitt

Loma Linda University Electronic Theses, Dissertations & Projects

Two new techniques for quantification of forces generated by an expansion screw apparatus placed between pairs of cylindrical endosseous titanium implants are described, along with preliminary data gained from their use in Macaca rhesus monkeys. Strain gages were bonded to the expansion apparatus and were calibrated either directly by micro load cell, or indirectly by Instron Machine to reflect the applied force.

Immediate loads of up to 6 kilograms have been applied to the implants with no increase in mobility as verified by a Periotest device. No previous studies on the orthodontic uses of implants have evaluated in vivo forces …

Signal Processing Methodologies For An Acoustic Fetal Heart Rate Monitor, Robert A. Pretlow Iii

Electrical & Computer Engineering Theses & Dissertations

Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively "trained" in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the …

Lecture Draft On Sensory Recall Device - 1980, Wendy J. Gordon

Scholarship Chronologically

Perception is a bodily function. The brain “sees” according to the orders which the optic nerve relays from its position at the back of the eye. Similarly, it is the brain which also "hears." As we know from our dreaming and our remembering, neither eye nor ear is indispensable to having the sensations of seeing and hearing.

Informed Consent And The Investigational Use Of Medical Devices: A Comparison Of Common Law Duties With Those Imposed On Researchers Under Section 520(G) Of The Medical Device Amendments Of 1976, Thomas G. Field Jr., Dominic Piacenza

Law Faculty Scholarship

This paper will deal with with exemption granted [under the Medical Device Amendments Act of 1976] for the investigational use of devices subject to premarket testing, and more particularly, with the obligation of an investigator seeking such exemption to secure an informed consent agreement from human subjects (or their representatives) under § 520(g)(3)(D) of the Act. It will also consider the relationship between the statutory obligation and that which might be imposed by the common law of negligence.

A Procedure For The Measurement Of Glosso-Maxillary Forces, Howard L. Lilly Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this investigation was to develop a clinically feasible procedure for recording the magnitudes of glosso-maxillary forces at four palatal loci using an electronic transducer system described by Lear et, al. (1965). Of particular interest was the development of a convenient and accurate calibration device for both intraoral and extraoral application. A further object of interest was the effect an acrylic carrier plate might introduce to the magnitude of force response. Finally whether or not any significant adaptation to the carrier plate or to the transducers occurs during a reasonable testing period (six to seven hours).

A calibration …

Sharpening And Care Of Mulesing Shears, A L. Jones

Journal of the Department of Agriculture, Western Australia, Series 4

THIS year will probably see more sheep mulesed in Western Australia than ever before.

It is not surprising, therefore, that some improvements have been made to the standard mulesing shears.

New modified shears make mulesing easier —but they must be properly sharpened.