Technology and Health Care - Volume 11, issue 3

Authors: Evrensel, Cahit A. | Khan, Md. Raquib U.

Article Type: Research Article

Abstract: Basic wave interaction mechanism between the laminar airflow and viscoelastic layer in a rigid tube is investigated numerically. The purpose is to explore the effect of mucus viscoelasticity on the stability of the coupled airflow-mucus system in pulmonary airways under clinical conditions where the serous layer is absent. The results indicate that the onset flow speed, for the initiation of unstable surface waves, is very sensitive to mucus viscosity and it may be as high as 35 times the elastic case for a very viscous mucus with the same elasticity. While the onset speed and wavelength increases, wave speed decreases …with increasing mucus viscosity, reducing from about 40% of the flow speed for elastic mucus to less than 1% for a very viscous mucus. Also, a case study for a patient with chronic bronchitis shows that large amplitude waves may form on the mucus surface during forced expiration. Show more

DOI: 10.3233/THC-2003-11301

Citation: Technology and Health Care, vol. 11, no. 3, pp. 149-159, 2003

Authors: Spanu, Christian E. | Hefzy, Mohamed Samir

Article Type: Research Article

Abstract: A two-dimensional anatomically based mathematical model of the human knee joint was developed to understand its biomechanics in deep flexion. The model was used to determine the internal knee loads as it simulates isometric quadriceps and hamstring co-contractions at different flexion angles during deep squat. It was found that in order to achieve deep flexion, large muscle forces are required, resulting in large tibio–femoral contact forces. In deep flexion, the femoral contact point was located on the most proximal point of the posterior condyle, location which was not affected by the level of quad activation. Conversely, the location of the …tibial contact point was highly affected by the level of quad activation. Both anterior and posterior fiber bundles of the posterior cruciate ligament were found to carry high loads when the knee is maximally flexed. These results point to the important role of the posterior cruciate ligament in this position, and suggest the necessity of retaining this ligament during total knee replacement (TKR) procedures that allows for maximum flexion angles. Furthermore, the present data provide an explanation why most TKR's do not allow deep flexion: while contact occurs on the most proximal points of the posterior condyles in normal knees, this portion of the condyles is not presently resurfaced when performing a TKR. Show more

Keywords: deep knee flexion, squat, isometric quad and hamstring co-contractions

DOI: 10.3233/THC-2003-11302

Citation: Technology and Health Care, vol. 11, no. 3, pp. 161-181, 2003

Authors: Davis, K.G. | Parnianpour, M.

Article Type: Research Article

Abstract: Spinal load models have become an increasingly valuable tool for the evaluation of the stress placed on the spine. In order to get an accurate representation of these spinal loads, they must be compared to known tolerance values. Bone mineral content and density of the lumbar spine of 23 males and 21 females was measured using a dual energy x-ray absorptiometry. Compression tolerance values were predicted by previously published studies based upon bone mineral levels. Anthropometric measurements were recorded and related to the compression tolerance values through the use of multivariate linear regression techniques. Compression tolerance values based on the …bone mineral content or density explains more of the individual variability than solely age-based estimates. Several anthropometric variable regression models were developed that resulted in moderate to good predictive power (R2 = 0.62 to 0.81). The current study describes a useful alternative to traditional tolerance estimates that accounts for individual differences requiring non-invasive and time-efficient procedures. Show more

DOI: 10.3233/THC-2003-11303

Citation: Technology and Health Care, vol. 11, no. 3, pp. 183-193, 2003

Authors: Roback, Kerstin | Herzog, Almut

Article Type: Research Article

Abstract: Due to an ageing population and improved treatment possibilities, a shortage in hospital beds is a fact in many countries. Home healthcare schemes using information technology (IT) are under development as a response to this and with the intention to produce a more cost-effective care. So far it has been shown that home healthcare is beneficial to certain patient groups. The trend is a widening of the criteria for admission to home healthcare, which means treatment in the home of more severe conditions that otherwise would require in-hospital care. Home informatics has the potential to become a means of providing …good care at home. In this process, it is important to consider what new risks will be encountered when placing electronic equipment in the home care environment. Continuous assessment and guidance is important in order to achieve a safe and effective care. Based on a review of current knowledge this paper presents an inventory of risks and adverse events specific to this area. It was found that risks and adverse events could stem from technology in itself, from human-technology interaction conditions or from the environment in which the technology is placed. As a result from the risk inventory, this paper proposes guidelines for the planning and assessment of IT-based hospital-at-home schemes . These assessment guidelines are specifically aimed at performance improvement and thus to be considered a complement to the more general guidelines on telehomecare adopted by the American Telemedicine Association (ATA) in October 2002. Show more

Keywords: assessment, home informatics, hospital-at-home, telehomecare

DOI: 10.3233/THC-2003-11304

Citation: Technology and Health Care, vol. 11, no. 3, pp. 195-206, 2003

Authors: Heybeli, Nurettin | Oktar, Faik Nuzhet | Ozyazgan, Sibel | Akkan, Gokhan | Ozsoy, Serhat

Article Type: Research Article

Abstract: Treatment of osteomyelitis with local antibiotic delivery systems has become a common practice in orthopaedic surgery. This study attempted to show that locally produced pure or bioglass reinforced plaster of Paris, hydroxyapatite and sodium alginate are promising biomaterials and mainly because of economical reasons and availability, may be an alternative in clinical practice, especially for developing countries. A total of 32 rabbits were divided into four groups (n:8). In group A, sodium alginate + cephazoline; in group B, plaster of Paris + bioglass + cephazoline; in group C, plaster of Paris + hydroxyapatite + cephazoline and in group D, plaster …of Paris + cephazoline were used. The blood serum cephazoline concentrations were analyzed by high performance liquid chromatography on days 1 to 10 everyday and then at days 13, 17, 18, 24, 25 and 30. The mean values ± standard deviations and median values of blood serum antibiotic concentrations for groups A, B, C and D were 1.45 ± 0.40 (1.42) mcg/ml, 1.53 ± 0.64 (1.31) mcg/ml, 1.92 ± 0.39 mcg/ml (1.90) and 1.41 ± 0.65 (1.25) mcg/ml, respectively. The detected antibiotic level was constantly over the minimum inhibitory concentration for Staphylococcus aureus. In conclusion, it can be stated that these materials are promising as a antibiotic delivery system even with simple production methods. Show more

Keywords: osteomyelitis, hydroxyapatite, plaster of Paris, calcium sulfate, sodium alginate, bioglass, local antibiotic delivery

DOI: 10.3233/THC-2003-11305

Citation: Technology and Health Care, vol. 11, no. 3, pp. 207-216, 2003