Temporal aspects of the effects of cooling on responses of single auditory nerve fibers

During an investigation of the effects of cochlear cooling on frequency tuning and input/output relations of single auditory nerve fibers in gerbil (Ohlemiller and Siegel (1994) Hear. Res. 80, 174-190), cooling-related changes in post-stimulus time histogram (PSTH) shape and phase-locking to tonebursts were characterized in a small sample of neurons. Local cochlear cooling by 5-10 degrees C below normal core temperature did not alter overall PSTH shape, although some evidence was found for a reduction in the time constants of rapid and short term rate adaptation. The relative contributions of rapid and short term response components appeared unaltered. Effects of cooling on phase-locking were assessed by calculating the synchronization index for responses to intense ( > 70 dB SPL) tonebursts at 0.5, 1.0, and 2.0 kHz. Synchronization filter functions exhibited modest reductions in both magnitude and the upper frequency limit of phase-locking. The effects of cooling on the temporal character of responses appear distinct from those of a simple reduction in stimulus intensity. Results are interpreted in terms of cooling-related changes in responses of cochlear hair cells and afferent neurons, and suggest that temperature artifacts are unlikely to underlie reported species differences in PSTH shape and phase-locking.     

Tumor register: information system for tumor centers (author's transl)

The different activities in the scope of the tumor center already shows in the multiplicity of concepts for which incidence register, therapy register, clinical register or the supplies register are only a few examples. Such terms circumscribe a few interests from the therapeutic, epidemiologic or clinical and scientific aspects, which are projected on tumor centers as an expectation or a duty. From the compilation of these interests a bundle of unspecific aims results for which a classification according to various levels of information is suggested. Only cooperation of all levels makes possible a tumor register as an information system for medicine which supports the tasks of all those involved and makes the questions of the population more easily and more quickly answerable.     

Inertia forces and moments balancing in robot manipulators: a review

The balancing of linkages is an integral part of the mechanism design. Despite its long history, mechanism balancing theory continues to be developed and new approaches and solutions are constantly being reported. Hence, the balancing problems are of continued interest to researchers. Several laboratories around the world are very active in this area and new results are published regularly. In recent decades, new challenges have presented themselves, particularly, the balancing of robots for fast manipulation. Various design concepts and methods for balancing of robot manipulators are available in the literature. The author believes that this is an appropriate moment to present the state of the art of the studies devoted to balancing of robot manipulators and to summarize their research results. Thus, the aim of this paper is to propose a review of shaking force and shaking moment balancing methods used in robotics, in particular, for serial and parallel architectures. The described methods are arranged into two principal parts: the resultant inertia force (shaking force) balancing and the resultant inertia moment (shaking moment) balancing. Then each part is divided into subgroups according to features of balancing methods and illustrated via kinematic schemes. At the end of the paper, the balanced robot manipulators having particular structures, the balancing taking into account the payload, the reactionless space robots and the optimization methods used in the balancing of robot manipulators are discussed.     

Theory of getter pump evaluation. Sticking coefficients of common gases on continuously deposited getter films

The principal points of a theory for the evaluation of vacuum devices with adsorbing walls, based on real values and distribution of molecular densities and sticking coefficients over the adsorbing surfaces, are discussed.A semi-empirical model for sorption on continuously deposited metal films is proposed. Relations for the dependences of sticking coefficients on temperature and sorption ratio for N₂, CO, O₂ and H₂ sorption on Ti-films are given.Further practical aspects of getter pump evaluation and related problems of optimization as well as concrete examples are discussed.     

Purification, crystallisation and preliminary X-ray diffraction study of ribosome inactivating protein: saporin

OBJECTIVES: To compare transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography for feasibility, safety, duration, patient acceptance and concordance in inducing wall motion abnormalities. BACKGROUND: Transesophageal atrial pacing is an effective method of increasing heart rate and has been used in the assessment of coronary artery disease. METHODS: Both tests were performed in sequence on the same patients in random order. Transesophageal atrial pacing stress echocardiography began at a heart rate of 10 beats/min above the baseline value and was increased by 20 beats/min every two min until 85% of the age-predicted maximum heart rate or another end point was reached. Dobutamine echocardiography was performed using three-min stages and a maximum dose of 40 microg/kg per min. Atropine (total dose < or =2 mg) was administered at the start of the 40 microg/kg per min stage if needed to augment heart rate or during pacing if Wenckebach heart block occurred. RESULTS: Transesophageal atrial pacing stress echocardiography was feasible in 100 of 104 patients (96%); the duration (8.6+/-3.6 min) was significantly shorter than that of dobutamine stress echocardiography (15.1+/-3.9 min) (p = 0.0001). With transesophageal atrial pacing stress echocardiography, the recovery period was shorter, symptoms and dysrhythmias were fewer, hypertension and hypotension were less common and target heart rate was more frequently achieved. No complications occurred with either test. Patient acceptance was satisfactory. Agreement between results of both tests was good for segmental wall motion scoring with a 16-segment model, scores 1 to 5 (kappa: rest, 0.79; peak, 0.57) and test interpretation (normal, ischemia, infarction or resting wall motion abnormality with ischemia) (kappa: 0.77). CONCLUSIONS: Transesophageal atrial pacing stress echocardiography is a feasible, well-tolerated alternative to dobutamine stress echocardiography. It can be performed rapidly and shows good agreement with dobutamine stress echocardiography in the induction of myocardial ischemia.     

Bone tumors of the coracoid process of the scapula

Bone tumors of the coracoid process of the scapula are rare, and diagnosis and treatment often are delayed. The records of 18 patients with bone tumors of the coracoid process were reviewed. Histologic types included eight cases of ordinary chondrosarcoma, three cases of dedifferentiated chondrosarcoma, two cases of osteoid osteoma, and one case each of osteosarcoma, plasmacytoma, lymphoma, giant cell tumor, and aneurysmal bone cyst. All 18 patients had shoulder pain, and eight of them had been treated with steroid injections for nonneoplastic conditions. Radiologically, chondrosarcoma did not always show clear cortical destruction, and one giant cell tumor had features mimicking those of chondrosarcoma. Five patients (three with dedifferentiated chondrosarcoma, one with chondrosarcoma, one with plasmacytoma) died of disease. The coracoid process was the site with a markedly high proportion of chondrosarcomas. Bone tumors of the coracoid process may be difficult to detect on plain radiographs. In the patient with persistent shoulder pain unresponsive to the selected treatment, additional imaging studies should be considered to eliminate the possibility of a bone lesion.