A method of estimating linear and angular accelerations in head impacts to pedestrians

In order to investigate the relationship between impact to the head and brain injury, we have developed a method, using information obtained from reconstruction of the collisions, of estimating the peak linear and angular accelerations of the head for pedestrian impacts on a vehicle. This information includes the location of the impact on the head, the impact velocity of the head, and the stiffness of the struck surface. In developing the method we assumed that the velocity of the head on striking the vehicle was the same as the velocity of the vehicle itself, that the force vector was normal to the surface of the skull, that the force-deflection curve characterising the combined response of the impacted surfaces was linear, and that the kinetic energy of the head immediately prior to impact was converted into strain energy in deforming the head and the vehicle structure. Only the loading phase of the impact was considered, there was no assumption of an elastic unloading phase. Using cadavers, the validity of these assumptions and hence the usefulness of the method were tested by comparing the estimates of peak linear acceleration with the results of 18 pedestrian-vehicle impact reconstructions. On average, the method underestimated the experimental values by about 15%, with a range of +/- 35%. The results from the application of this method are currently being used to study the relationship between the magnitude and direction of the impact to the head and the distribution and severity of the brain injury resulting from actual collisions.     

Flexor carpi radialis tendinitis. Part I: Operative anatomy

The anatomical characteristics of the flexor carpi radialis tendon, the tendon sheath, the tunnel boundaries, and the adjacent structures were examined in twenty-five adult cadaveric specimens. Transverse and sagittal sections of the wrist and forearm, tenograms, and histological sections of the tendon were made from two additional specimens each. The musculotendinous portion of the flexor carpi radialis tendon begins an average of fifteen centimeters (range, twelve to seventeen centimeters) proximal to the radiocarpal joint; the muscular fibers end an average of eight centimeters (range, six to nine centimeters) proximal to the wrist. The synovial sheath extends from the origin to the insertion. The tendon enters a fibro-osseous tunnel at the proximal border of the trapezium and is separated from the carpal canal by a thick septum that functions, at its distal border, as a pivot point for the flexor pollicis longus. Within the tunnel, the tendon occupies 90 per cent of the available space and is in direct contact with the slightly roughened surface of the trapezium. The tendon lies within a few millimeters of the distal aspect of the radius, the scaphoid tubercle, the scaphoid-trapezium-trapezoid joint, and the carpometacarpal joint of the thumb. In most patients, the flexor carpi radialis tendon is inserted at three locations. A small slip is connected to the trapezial crest or tuberosity; 80 per cent of the remaining tendon is inserted on the base of the second metacarpal and 20 per cent, on the base of the third metacarpal. The deep palmar arch is located two to three millimeters distal to the insertion of the tendon.     

Respirator mask design modules and their interactions

The respirator performance rating table (PRT) scheme has been offered as a way to organize physiological information to be useful for mask design. Designers do not usually deal exclusively with one kind or another of mask physiological effect. This paper presents normal mask design modules and how they relate to mask physiological effects as given in the PRT.     

An epidemiologic study of non-occupational lifting as a risk factor for herniated lumbar intervertebral disc. The Northeast Collaborative Group on Low Back Pain

An epidemiologic case-control study of herniated lumbar intervertebral disc was conducted in Springfield, Massachusetts, New Brunswick, New Jersey, and New York, New York, to evaluate the role of several possible risk factors in the etiology of this disorder. Patients with signs and symptoms of herniated lumbar disc (N = 287) were matched to control subjects without back pain by age, sex, source of care, and geographic area. Of the total case-subject group, 177 were confirmed by surgery, computed tomographic scan, myelogram, or magnetic resonance imaging. This article focuses on non-occupational lifting, an activity not previously reported on. Frequent lifting of objects or children weighing 25 or more pounds with knees straight and back bent was associated with increased risk of herniated lumbar disc. This association was particularly strong among confirmed case subjects (relative risk = 3.95). Positive associations among confirmed case subjects were also seen for frequent lifting with arms extended (relative risk = 1.87) and twisting while lifting (relative risk = 1.90). No associations were found for frequent stretching or carrying. If confirmed in other investigations, these data suggest that instruction in lifting techniques should be extended into the home.     

Hörsaalmanagement

An innovative system for efficient lecture-room scheduling is introduced. The core of the system is a new mathematical model. For the solution a column generation approach is presented. A numerical investigation shows that the approach has a very high solution quality. All considered instances of the problem are solved almost optimally within reasonable time. For the application an internet-based system has been developed. All processes of information, communication, and scheduling are implemented in the system.