Biomedical subjects
Publications and source records attributed to R Poll.
For the cultivation of animal cells perfused cell culture systems are advantageous. The measurement of the process parameters for the check of the culture is difficult through the small volumes and dimensions. A developed measuring system allows the measuring of the parameters temperature, pH-value and dissolved oxygen.
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For cultivating animal cells in bioreactors the maintenance of a fixed pH-value is of elementary importance. In a perfused cell culture system the pH-value is measured by electrochemical flow rate sensors. For the acceptance of a technical solution the integration in complex workplaces is necessary, thereby small size and low costs are the main features. For that a special measurement module was developed, consisting of measuring amplifier and microcontroller component with CAN-Bus-interface.
For computer-aided data acquisition and automated running of experiments in cell cultivation reactors networking of all sensoric and actoric devices is required. A low cost and high performance solution to this demand can be found by using the widely established CAN (Controller Area Network) bus. If standard PCs running MS Windows are used to control this network special measures have to be taken to prevent loss of data caused by differences in the computing power of the PC on one hand and microcontroller-based devices on the other.
OBJECTIVES: To determine the prevalence of Chlamydia trachomatis infection in male undergraduates and to investigate whether prevalence increases with time spent at university. To investigate the feasibility of screening men for C trachomatis by self sampling and posting of urine specimens. METHODS: The study design was a postal survey undertaken by the Department of Genito-Urinary Medicine (GUM) and Student University Health Service (SUHS) in SHEFFIELD: 2607 male undergraduates from the SUHS patient list were invited to participate in the study by providing a first void urine specimen and posting it to the laboratory. The main outcome measure was the detection of C trachomatis infection. RESULTS: 758 students participated in the study, a response rate of 29.1%. Nine students (1.2%) tested positive for C trachomatis. The prevalence of infection in the first, second, and third year of study was 0.7%, 1.5%, and 1.6% of participants respectively. There was no statistically significant difference in prevalence of infection between first and third year students (chi(2) test, p = 0.32). However, students with chlamydia had a higher median age (Mann-Whitney U test, p < or = 0.05). Contact tracing identified four further cases of C trachomatis infection. CONCLUSION: Screening for C trachomatis infection by postal survey is feasible. However, the response rate in this study was poor and the estimated sample size was not reached. Therefore, it has not been possible to determine the true prevalence of infection in this population or to accurately assess changes in prevalence with time spent at university.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Common heart arrhythmia monitors are limited to the electrical activity of the ventricles. Severe cardiac malfunctions exhibit typical defects of atrioventricular conduction which often can be efficiently treated with medicine or electrotherapy. The method described here enables the detection of complete atrioventricular blocks and may be used for the improvement of arrhythmia monitoring.
An already published method for automatic processing of a single ECG signal was tested on the base of a data set of a foreign clinic. The yielded results of the P-wave recognition (recognition ratio 87.1% with a failure ratio of 6.0%) confirm fully its reliability reported before. This paper gives a valuation of the method from the clinical point of view by reference to literature considering technical questions. The most important application of this method is the ECG processing under pressure requiring precise time - measuring, classification of separate patterns and recognition even of non-marked parts of the signal course as P-waves, ST-segments and T-waves. Methodical adaption of the method to the special range of application is necessary in all cases. General questions for prospective evaluation of a given automatic recognition system by physicians are discussed briefly.
Algorithms for digital pattern recognition optimized for the demands of the physician are urgently needed. They have to provide high levels of recognition, accuracy, reliability, artefact rejection and flexibility in detecting different types of signal time-course. The microcomputer algorithm presented here works on the principle of Walsh-transformation of signal sections and in-image judging. The algorithm efficiently solves simple tasks, and also recognizes, for instance, ECG P-waves using the same algorithm. A test with 1054 randomly selected outpatient's ECG and with an additional 72 ECGs of inpatients with clinically proved myocardial infarcts produced the following results: The recognition ratio for the R-wave amounted to 98.8% with a failure ratio of 2.3%, while an initial common P-T-pattern was correctly recognized in 80.3% of cases, with a failure ratio of 4.9%. The algorithm was implemented on a Z80 microprocessor and on a single-chip computer Z8.