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At least 541 records · Page 30Linked to original sources
PubMed1977

["On-line artefact rejection" at electric response audiometry (ERA). Use of an active, analog delay line as buffer in combination with a recognition of disturbing signals (author's transl)].

Some brief theoretical considerations about an artefact rejection basing upon the valuation of amplitudes are followed by a report on a new development of an "on-line artefact rejection" which uses an active analog delay line as buffer combined with a recognition of disturbing signals and can easily operate together with simple averagers. The advantages are shown and discussed by means of examples, but also the mistakes which can arise by too great limitations of the signal's level. Technical details are described briefly.

Acoustic Stimulation↗
PubMed1977

A multifunctional prosthesis control system based on time series identification of EMG signals using microprocessors.

This paper describes a real-time system for separation among several limb functions, in order to provide multifunctional control of an upper-limb prosthesis for above-elbow amputees. The system employs microprocessor hardware and is based on identification of voluntary myoelectric signals resulting from isometric contractions of the musculature of the residual limb, and on subsequent discrimination of these signals for control of the several degrees of motion of the prosthesis. The system requires only one to two electrode sites. (Contrary to the usual placement of electrode pairs directly over specific muscle bellies, to eliminate crosstalk, we prefer to place our electrode pair between muscles so as to acquire the different weakly-correlated signals associated with each of several different voluntary functions). The system satisfies the various practical constraints of weight, volume, and speed, as arise in practical prostheses. Preliminary amputee tests on the system have resulted in an 85 percent success rate using 8-bit double-precision micro-computer hardware.

Adult↗
PubMedDate not supplied

Continuous ATP regeneration process with stable acetate kinase.

Heat-stable acetate kinase (AK) from Bacillus stearothermophilus was successfully immobilized covalently to Sepharose resin by several conventional methods including carbodiimide, hydroxysuccinimide, cyanogen bromide, and glutaraldehyde and also by a new method which utilizes a bifunctional ADP derivative as a spacer. The latter method gave a higher yield in terms of enzyme activity than the conventional methods. The properties and kinetics of the immobilized AK were studied batchwise and in a column. The Michaelis-Menten equation could be applied to the immobilized AK column. The apparent Km values of ADP and acetyl phosphate for immobilized AK were not significantly different from those for free AK. The pH-activity profile of immobilized AK was similar to that of free AK. The heat stability of immobilized AK was markedly improved as compared with free AK. The immobilized AK retained more than 80% of the initial activity after continuous operation at 30 degrees C for 1 month. It was shown that the immobilized AK from B. stearothermophilus could be utilized as an ATP regeneration system in the bioreactor.

Acetate Kinase↗
PubMed1978

[Pacemakers: concerning check-ups (author's transl)].

The Authors have re-examined their case histories of 1503 patients who have had 2459 pacemakers implanted and who have undergone check-ups as outpatients. All the complications which have arisen from 1967 to the present have been taken into consideration. The total number of complications has been found in 355 patients with 14% of the total number of pacemakers and they have been subdivided into 3 groups: 1st group: complications arising during the stay in hospital (110); 2nd group: complications arising after discharge from hospital and discovered by the patient (239); 3rd group: complications found casually during outpatients' check-ups (6). Of the complications found after discharge, 97% belong to the second group and only 3% to the third group. 657 substituted pacemakers have also been taken into consideration with the purpose of finding out the parameters which showed up as the battery was running down. Out of 145 pacemakers substituted because of flat batteries, 130 (90%) have shown brusque variations in the frequency of stimulation, while only 15 (10%) have shown variations in other parameters (width, length of impulse, etc). The Authors therefore retain that a periodic outpatients' check-up of the pacemakers is of little use as regards the patients' safety and the complete utilization of the device, while they advise that the patient be educated so as to be able to carry out his own daily control of the pacemaker.

Bioelectric Energy Sources↗
PubMedDate not supplied

Construction of a system for the regeneration of adenosine 5'-triphosphate, which supplies energy to bioreactor.

An engineering model was successfully developed for an ATP regeneration system by using two enzymes, acetate kinase (AK) and adenylate kinase (AdK), both obtained from the thermophile Bacillus stearothermophilus. This model is composed of five units: a substrate unit consisting of substrate solutions--AMP, ATP, and acetyl phosphate (AcOP)--an enzymatic reactor unit consisting of AK and AdK immobilized to Sepharose 4B, an auto sampler unit, an analytical unit made up of high-performance liquid chromatography, and a control unit made up of a microcomputer. Operation of the four units could be systematically controlled by the microcomputer. Fundamental, operational conditions were examined using this engineering model. The conversion of AMP to ATP concentration and space velocity (SV). The minimum amount of ATP, which is required to obtain the 100% conversion of AMP to ATP, was determined to be about 4% of AMP concentration. The conversion of AMP to ATP was controlled effectively by changing the SV value. Based on the above experimental data, the continuous operation of an ATP regeneration system was tested at pH 7.5 and 30 degrees C under the conditions of 1.59 mM AMP, 0.084 mM ATP, and 5.0 mM AcOP. It was found that the conversion of AMP to ATP was more than 99% over a period of 6 days without changing SV.

Acetate Kinase↗
PubMed1984

The road ahead.

Explore the source record for details and available documents.

Artificial Limbs↗
PubMed1983

Functional comparison of upper extremity amputees using myoelectric and conventional prostheses.

Upper extremity amputees were tested on a standardized series of tasks using a myoelectric hand, a conventional prosthesis (cable-controlled hook), and their normal hand (unilateral amputees only). They answered also a questionnaire on activities of daily living (ADL) and provided other prosthetic information. Amputees who had been fitted only with a conventional prosthesis, and used their prosthesis regularly, tended to wear the prosthesis more hours per day (14 hours) than amputees fitted with a myoelectric hand (9.6 hours), some of whom continued to use a conventional prosthesis for some jobs. However, the amputees with myoelectric prostheses had a greater functional range of motion (ROM) than those with a conventional prosthesis, and many regular wearers of a myoelectric prosthesis had long since rejected a conventional prosthesis. Amputees took about 2.5 times as long to complete the tasks tested with a conventional prosthesis and about five times as long with a myoelectric prosthesis than with their normal hand. Despite the slower function, more than 60% of below-elbow (B-E) amputees accepted the myoelectric prosthesis in preference to a conventional prosthesis, which they had all been fitted with previously. Others preferred to continue using a conventional prosthesis to which they had become accustomed (13%) or no prosthesis (26%). The combination of function, ROM, and cosmetic appearance of a myoelectric prosthesis is preferred by most B-E amputees, despite its slower performance at the present time.

Activities of Daily Living↗