Joseph Barbenel - Academia.edu (original) (raw)

Papers by Joseph Barbenel

Pressure sore prevalence and incidence were assessed in 275 patients who were admitted to a well-... more Pressure sore prevalence and incidence were assessed in 275 patients who were admitted to a well-staffed internal medicine ward during a 12-month study period or who were present on day 1. Pressure sore risk was assessed by use of the Braden scale and patients scoring 16 or less were provided with intensive preventive care. During the study period 5.1% (95% confidence interval 2.7-7.8) of 275 patients had pressure sores (prevalence) and 4.4% (1.9-6.9) developed sores (incidence). None of the 239 patients who were assessed as not being at risk developed a sore. 36 patients were assessed as being at risk at some time during the study and 12 of these developed sores despite receiving high-quality preventive care. The results suggest that not all pressure sores can be prevented in severely ill patients. We believe that the 4.4% incidence of sores in this study approaches the current limit of prevention.

Journal of Wound Care

Effective compression bandaging is critical for leg ulcer care. The bandaging technique of 18 nur... more Effective compression bandaging is critical for leg ulcer care. The bandaging technique of 18 nurses was assessed using a pressure monitor and the assessment repeated after training with feedback from the monitor. The use of a bandage marked with a tension indicator resulted in a small, insignificant improvement in bandaging technique. The combination of training and feedback significantly improved the nurses&amp;amp;amp;amp;amp;#39; bandaging technique. This improvement was sustained on retesting two weeks later.

Biomedizinische Technik/Biomedical Engineering, 2000

Thrombosis and Haemostasis

Platelet aggregation was studied at 37 degrees C in citrated whole human blood, using the Ultra F... more Platelet aggregation was studied at 37 degrees C in citrated whole human blood, using the Ultra Flo 100 Whole Blood Platelet Counter. Aggregation was measured as a fall in the number of single platelets following addition of an aggregating agent. At peak aggregation, the fall in the number of platelets induced by ADP (10 microM), collagen (1 microgram/ml) or thrombin (0.2 U/ml) was about 90%. When blood was incubated with the prostacyclin-analogue ZK36374, the aggregation responses to ADP, collagen and thrombin were reduced with IC50's = 0.5, 1.5 and 3 nM respectively and the corresponding IC100's were: 1, 3 and 12 nM. When ZK36374 was added at peak aggregation, the number of single platelets increased significantly due to disaggregation of preformed platelet aggregates. It is concluded that the present technique represents a rapid, sensitive and more physiological approach for investigating the effects of pharmacological agents on platelet aggregation.

European cells & materials

Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2002

We present our results of the effects of coplanar electrode's geometrical factors on the meas... more We present our results of the effects of coplanar electrode's geometrical factors on the measurement of bioelectrical impedance, one of the most widely measured physical properties in biomedical applications. Coplanar electrodes of different shapes and sizes were used to measure the electrical impedance of saline at different concentration and blood reconstituted at different hematocrit in either plasma or serum. The

2002 IEEE Ultrasonics Symposium, 2002. Proceedings., 2002

Despite significant advances in ultrasonic instrumentation, accurate and repeatable measurements ... more Despite significant advances in ultrasonic instrumentation, accurate and repeatable measurements of skin structure and dimensions remain problematic. Skin structure is complicated and structural boundaries are non-planar and may be diffuse, inhibiting the application of inversion methods for skin thickness measurement. Coupling a transducer to the skin surface with water or aqueous gel can produce significant artefacts in thickness measurement, which

IEEE Ultrasonics Symposium, 2004, 2004

The &amp;#39;inversion layer&amp;#39; transducer (ILT), incorporating oppositely ... more The &amp;#39;inversion layer&amp;#39; transducer (ILT), incorporating oppositely polarised piezoelectric zones across the thickness, has attracted recent interest. Such devices offer interesting properties particularly with regard to harmonic generation and the potential for wideband behaviour. This paper attempts to investigate the fundamental physical mechanisms that take place, through the creation of a 1D, linear systems model of the thickness mode ILT

IEEE Symposium on Ultrasonics, 2003, 2003

Much recent interest has been expressed regarding inversion layer piezoelectric transducers. Thes... more Much recent interest has been expressed regarding inversion layer piezoelectric transducers. These are multi-layered devices, incorporating a reversal in piezoelectric polarisation in the stack thickness, creating the potential for extended bandwidth and enhanced even harmonic sensitivity in thickness drive structures. The transducer properties are determined in turn by the relative dimensions of the polarised zones, in addition to the mechanical

With the rapid development of tissue engineering and gene therapy, collagen-based biomaterials ar... more With the rapid development of tissue engineering and gene therapy, collagen-based biomaterials are frequently used as cell transplant devices; an example is tissue-engineered skin substitutes. In this study of low level laser therapy (LLLT) we determined the influence of the irradiation and treatment parameters on the proliferation rate of 3T3 mouse fibroblast cells cultured on collagen-glycosaminoglycan (GAG) lattices and Petri

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011

Biomedical Engineers should be prepared to adapt to existing or forecasted needs. There is a stro... more Biomedical Engineers should be prepared to adapt to existing or forecasted needs. There is a strong pressure on education, training and life long learning programs to continuously adapt their objectives in order to face new requirements and challenges. The main objective of the TEMPUS IV, CRH-BME project is to update existing curricula in the field of Biomedical Engineering (BME) in order to meet recent and future developments in the area, address new emerging inter-disciplinary domains that appear as a result of the R&D progress and respond to the BME job market demands. The first step is to extensively review the curricula in the BME education field. In this paper, a proposal for a generic curriculum in the BME education is presented, in order to meet recent and future developments and respond to the demands of the BME job market. Adoption of the core program structure will facilitate harmonization of studies as well as student and staff exchange across Europe, thus promoting the ...

International journal of oral and maxillofacial surgery, 2012

The errors produced by occlusal wafers constructed on casts of the teeth mounted on a standard ar... more The errors produced by occlusal wafers constructed on casts of the teeth mounted on a standard articulator and an improved orthognathic articulator were investigated by carrying out simulated orthognathic surgery on plastic skulls. The wafers were used to relocate the position of the maxillae of the skulls. The vertical and horizontal displacements of the maxillae were determined from measurements of the positions of markers on the skull and teeth. Comparison of the magnitudes of the actual and intended movements showed that wafers constructed on the standard articulator had systematic prediction errors of up to 5mm, but the improved orthognathic articulator showed much smaller random errors. There was a statistically significant improvement in overall accuracy in predicting maxillary Le Fort I position with the use of the improved orthognathic articulator which the authors recommend for clinical use.

Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine, 2002

A new capillary viscometer is described in which a column of blood is discharged under a constant... more A new capillary viscometer is described in which a column of blood is discharged under a constant pressure, producing a variety of shear stresses during a single test. Measurement of the viscosity of Newtonian sucrose solutions showed good agreement between the viscosity determined from the new system and the expected values. The viscosity of whole blood was measured in a cone-and-plate viscometer at a wide range of shear rates and characterized using a power law model; good agreement was obtained between the capillary and rotational results at low and medium shear rates. High shear rate results could also be obtained by increasing the driving pressure. The new viscometer proved to be simple to use, utilized a small test volume and produced reliable results.

Biorheology

The influence of hematocrit on red blood cell aggregation was investigated using a modified autom... more The influence of hematocrit on red blood cell aggregation was investigated using a modified automated Myrenne Aggregometer System. Hematocrit values ranged from 20-70% at 10% increments, and were produced by resuspending washed red cells in autologous plasma. The Myrenne System produced seven kinetic parameters of red cell aggregation. The results indicate that hematocrit (Hct) had a strong and nonlinear effect on erythrocyte aggregability. At both low and high hematocrit, the aggregation intensity (AI) tends to decrease, reaching a plateau at 40% hematocrit. The disaggregation shear rate demonstrates an exponential relationship as In gamma TMIN = 3.29-0.0837 Hct. Time constants of the aggregation process such as T1/2, TSLOW and TFAST were rather inconsistent. The increase of hematocrit increased the rate of the fast phase aggregation and slightly slowed the secondary aggregation.

Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft für Medizinische Physik and the European Federation of Organisations for Medical Physics, 1985

L929 mouse fibroblasts were exposed to sinusoidally varying magnetic fields. Compared with contro... more L929 mouse fibroblasts were exposed to sinusoidally varying magnetic fields. Compared with controls the exposed cells showed differences in morphology, clustering and orientation with respect to the magnetic fields and an increased mitotic rate. These effects are time dependent, but occurred at frequencies of 10 and 27 MHz.

Clinical science (London, England : 1979), 1989

1. Aggregation assays are a commonly used technique for the study of granulocyte activation. Thes... more 1. Aggregation assays are a commonly used technique for the study of granulocyte activation. These studies are usually performed using a pure cell suspension in buffer. This necessitates a separation procedure which is time-consuming and may modify the function of the cells. Interaction between different cell types is precluded. 2. To avoid these disadvantages a method was developed which quantifies granulocyte aggregation in whole blood. Samples drawn from an incubated vessel before and after the addition of a chemotactic stimulus were fixed with formaldehyde to prevent disaggregation. Erythrocytes were then removed by chemical lysis and using an electronic cell-sizing device the number of single cells and aggregates could then be easily measured. 3. Results from a group of volunteers showed a rapid and reversible response to a chemotactic tripeptide, with a fall in single granulocyte count and the appearance of doublets and triplets. Lymphocytes were unaffected. Intra-assay reprod...

IFMBE Proceedings, 2011