Fall from height in a stairwell--mechanics and simulation analysis.
The range of problems considered in the biomechanical analysis of a fall from height has been presented. A complicated case of a fall in a stairwell was investigated, the analysis of which demonstrates the research scale and aspect multitude. The scope of the article was restricted to the analysis of biomechanical problems and the simulation analysis of the event. A virtual 3D model of the stairwell was built using sketches, photographs and photogrammetric techniques. A dummy created according to the victim's data was parameterised. Using the PC-Crash biomechanical module a series of several hundred simulations were run following the adopted research plan, allowing for pre-formulated boundary conditions. The region of the stairwell where the accident was likely to originate and the victim's initial configuration were identified. It was proved that biomechanical simulation can bring invaluable benefits in exposing the mechanism of an event and verification of various hypotheses. Despite general similarities, each fall has its own specificity, which, making the use of methodological generalisations difficult, increases the significance of casuistry. The presented analysis can prove very useful in providing guidelines on investigating other cases.
Prognostic factors in victims of falls from height*
Objective:Falls from height cause significant mortality in the urban environment, but reliable prognostic factors have not been identified. Even the intuitive relation between the distance fallen and mortality rate has been questioned. Our objective was to determine factors predictive of increased mortality rate in victims of falls from height. Design:Clinical observational study, retrospective for January 1998 to May 1999 and prospective from June 1999 to September 2000. Setting:The study population was drawn from Seine-Saint-Denis, an urban region near Paris with 1.3 million inhabitants treated by a French out-of-hospital medical emergencies unit. Patients:Patients were victims of falls from height >3 m, age >12 yrs. Study entry was performed on the scene by an emergency physician from the medical emergencies unit. Interventions:None. Measurements and Main Results:Studied data included age, gender, circumstances of fall, height of fall, nature of the impact surface (soft or hard), transient impact preceding final impact, and part of the body touching the ground first. The primary end point was mortality. The study included 287 patients, 116 (40%) during the retrospective phase and 171 (60%) during the prospective phase. Ninety-seven patients (34%) ultimately died. In multivariate analysis, age (mean, 41.6 ± 16.6 yrs in patients who died vs. 34.9 ± 14.9 in survivors; odds ratio, 1.05; p < .0005); height of fall (median, 5.0; 3.8–8.0 vs. 2.0; 1.2–3.0 floors; odds ratio, 1.24; p < .0001); nature of the impact surface (hard in 39% vs. soft in 22%; odds ratio, 2.7; p < .05); and head, anterior, and lateral body surfaces touching the ground first (with respectively mortality rates of 44%, odds ratio, 16.7, p = .0001; 57%, odds ratio, 10.6, p < 0.005; 32%, odds ratio, 11.1, p < .001) were independently correlated with the final mortality rate. Conclusions:Patient age, height of fall, impact surface nature, and body part first touching the ground are independent prognostic factors in victims of falls from height.
Degradable polymers : principles and applications
1. Why Biodegradable Polymers? G. Scott. 2. An Overview of Biodegradable Polymers and Biodegradation of Polymers S.H. Huang. 3. Degradation and Stabilization of Carbon-Chain Polymers G. Scott. 4. Techniques and Methods of Polymer Degradation S. Karlsson, A.-C. Albertsson. 5. Biodegradation of Aliphatic Polyesters Suming Li, M. Vert. 6. Starch-Polymer Composites C. Bastioli. 7. Polymers from Renewable Sources E. Chiellini, et al. 8. Sustainable Poly(Hydroxyalkanoate) (PHA) Production G. Braunegg. 9. Polyhydroxyalkanoates: Properties and Modification for High Volume Application I. Chodak. 10. Biodegradable Polymers in Medicine E Piskin. 11. Environmentally Biodegradable Water-Soluble Polymers G. Swift. 12. Plastics and the Environment J. Guillet. 13. Degradable Hydrocarbon Polymers in Waste and Litter Control G. Scott, D.M. Wiles. Subject Index.