Application of ideal pressure distribution in development process of automobile seats.

BACKGROUND: In designing a car seat the ideal pressure distribution is important as it is the largest contact surface between the human and the car. Because of obstacles hindering a more general application of the ideal pressure distribution in seating design, multidimensional measuring techniques are necessary with extensive user tests. OBJECTIVE: The objective of this study is to apply and integrate the knowledge about the ideal pressure distribution in the seat design process for a car manufacturer in an efficient way. METHODS: Ideal pressure distribution was combined with pressure measurement, in this case pressure mats. In order to integrate this theoretical knowledge of seating comfort in the seat development process for a car manufacturer a special user interface was defined and developed. RESULTS: The mapping of the measured pressure distribution in real-time and accurately scaled to actual seats during test setups directly lead to design implications for seat design even during the test situation. Detailed analysis of the subject's feedback was correlated with objective measurements of the subject's pressure distribution in real time. Therefore existing seating characteristics were taken into account as well. CONCLUSIONS: A user interface can incorporate theoretical and validated 'state of the art' models of comfort. Consequently, this information can reduce extensive testing and lead to more detailed results in a shorter time period.

Technical note: spine loading in automotive seating.

For car manufacturers, seat comfort is becoming more important in distinguishing themselves from their competitors. Therefore, many studies on participative seat comfort are carried out. In this paper, an objective assessment approach is reported which evaluates the concept of "optimal load distribution", based on the identification of a close relationship between the pressure on the seat and the discomfort felt by the person sitting. An in vivo measurement of the pressure in the spinal disc, which is an indicator of the load in the spine, was performed. For this research, a pressure sensor was implanted with a canula in the middle of the disc intervertebralis of a participant. The local pressure on the disc was established for the participant in an automobile seat set in various seat positions. The results indicate that in the seat position with the pressure distribution corresponding to the most comfortable posture the pressure in the intervertebral disc is lowest. The pressure in this position is 0.5 bar, while in the upright seated position the pressure is 1.6 bar.

Computer simulation for ergonomic improvements in laparoscopic surgery.

It is the aim of this study to reduce the stress and strain of the medical staff during laparoscopic operations, and, simultaneously, to increase the safety and efficiency of an integrated operation room (OR) by an ergonomic redesign. This was attempted by a computer simulation approach using free modelling of the OR and 3D human models (manikins). After defining ergonomically "ideal" postures, optimal solutions for key elements of an ergonomic design of the OR (position and height of the image displays, height of the OR table and the Mayo stand) could be evaluated with special regard to the different individual body size of each member of the team. These data should be useful for the development of team adapted, user friendly integrated OR suites of the future.

Ergonomic assessment of the static stress confronted by surgeons during laparoscopic cholecystectomy.

BACKGROUND: Only a few reports on static strain in the spine, neck, and head of the surgeon are available, describing it as "distinctly harmful." The aim of this study was to objectively prove the static burden during laparoscopic operations. For this, new industrial software called PCMAN was used, capable of measuring and comparing the postures of the surgeon at different monitor placements. METHODS: Two simultaneous and synchronized video recordings of laparoscopic cholecystectomies (LC) were done using miniDV digital camcorders with the cameras standing at a 90 degrees angle to each other. Twenty operations were performed using two different placements of the monitor. In 10 cases, the monitor was placed at the patient's head in the center, and in 10 cases at the left side of the patient. Using the time codes of the recordings, different steps of the operation were identified, and the duration of these measured in seconds. Very characteristic, longer lasting postures were imported to and analyzed with the software. Results of the different setups were compared to each other, and to an "ideal" comfort posture. RESULTS: During the intermediate steps of the operations the rate of static phases is significantly higher. Measuring the typical postures of these phases the trunk and head are significantly more rotated and bent than in comfort positions. When the monitor was at the side of the patient facing the surgeon, results were closer to the comfort posture. CONCLUSIONS: It was proven that surgeons are confronted by significant static burden during LC. The software used was able to evaluate objectively the static posture of the surgeon during series of LC. Results also confirmed that the position of monitors significantly influences the surgeon's posture. Best setups for the whole team can be achieved by adjustable multiple monitor systems.

[Backward fall in Alpine skiing. Case study of the effect of the back spoiler of the ski shoe on muscle activity and kinematics]. / Der Rückwärtsfall im alpinen Skilauf. Fallstudie zum Einfluss des Heckspoilers des Skischuhes auf die Muskelaktivität und die Kinematik.

For the investigation of the boot-induced anterior cruciate ligament injury and experimental case study with a prototype ski boot was performed. The back spoiler of this boot was designed to yield by only some degrees with a certain level of backward moment. A mechanical switch allowed to activate or to block this mechanism. Ten jumps over a prepared hill with activated and ten jumps with blocked spoiler mechanism were performed in randomised order. During the jump and landing the EMG of eight lower extremity muscles were recorded and synchronised to two S-VHS cameras suitable for 2D-analysis of the angle kinematics. The aim of these experiments was to quantify the muscular and kinematic effects caused by the new spoiler characteristics and also to establish a method for their judgement. For the quantification of the muscular effects an activity quotient was defined and for the analysis of the kinematics the time history of three body angles and their variation between the trials were found to be appropriate. The results of this case study showed an increase of the activity quotient for all observed muscles and a higher accuracy of motion with the activated spoiler mechanism. These findings an be taken as an indication for better muscular joint guiding in the knee and justify a randomised field study using the proposed methods.

Vibrio parahaemolyticus -- a marine pathogen detected in South African coastal waters.

Vibrio parahaemolyticus has been detected in the Natal and Eastern Cape costal water of South Africa. As a proven cause of gastro-enteritis or a potential pathogen to humans, it is an organism of importance to public health. Outlines of the history, pathogenicity and identification are given, as well as the results of the local investigation of this organism.

Cat bite transmission of Yersinia pestis infection to man.

The transmission of bubonic plague from the kitten of a domestic cat to a man by means of a bite on a finger is described. The human case was complicated by the development of a secondary meningitis, followed, after specific therapy, by protracted recovery. The kitten showed swollen lymph nodes of the head and neck, frothing at the mouth and nostrils, and signs of an acute infectious disease which had a fatal termination. Yersinia pestis was isolated on about the 8th day from the cerebrospinal fluid of the man. The foster mother of the kitten exhibited signs of spinal and cerebral meningitis but recovered following treatment; her serum contained plague antibody levels of 1:512 and 1:1024 on the 22nd and 34th days respectively after the first evidence of illness. Three litter mates of the kitten also died. The outbreak occurred on a farm in the Graaff-Reinet district of the eastern Cape Province, which is situated about 160 km from the nearest known natural plague focus.