Biomedical subjects

V Bonin

Publications and source records attributed to V Bonin.

6 recordsLinked to original sources

PubMed2005

Growth and survival of Escherichia coli O157:H7 during the manufacture and ripening of raw goat milk lactic cheeses.

The behaviour of Escherichia coli O157:H7 was studied during the manufacture and ripening of raw goat milk lactic cheeses. Cheese was manufactured from raw milk in the laboratory and inoculated with E. coli O157:H7 to a final concentration of 10, 100 and 1000 cfu ml(-1). E. coli O157:H7 was counted by CT-SMAC (Mac Conkey Sorbitol Agar with cefixim and tellurite) and O157:H7 ID throughout the manufacturing and ripening processes. When the milk was inoculated with 10, 100 or 1000 cfu ml(-1), counts decreased to less than 1 log(10) g(-1) in curds just prior to moulding. However, viable E. coli O157:H7 were found in cheeses throughout processing, and even after 42 days of ripening. Results indicate that E. coli O157:H7 survives the lactic cheese manufacturing process. Thus, the presence of low numbers of E. coli O157:H7 in milk destined for the production of raw milk lactic cheeses can constitute a threat to the consumer.

Animals↗

PubMed2001

Efficient evaluation of serial sections by iterative Gabor matching.

Evaluation of electron microscopic images of serial sections is a time-consuming process requiring a high level of expertise. Here we present an algorithm to ease and accelerate this process. It is a modification of an algorithm successfully used in computer vision for object recognition. However, rather than recognising individual structures, we estimate the spatial mapping of a whole section onto the consecutive one. This mapping is used to transfer labelled information of the very first section, e.g. a classification by a human expert of different visible structures, onto structures visible in the next section. We investigate its performance on an artificially constructed benchmark as well as on real electron microscopic samples taken in primary visual cortex and demonstrate its potential for dramatically facilitating the evaluation process of serial sections.

Algorithms↗

PubMed2000

Determination of the in vivo loading of the lumbar spine with a new approach directly at the workplace--first results for nurses.

OBJECTIVE: To determine the magnitude of workplace loading for nurses with and without a history of low back pain. DESIGN: A measurement system for the assessment of workplace loading as well as a model for the calculation of lumbo-sacral junction loading was designed and applied to a group of 12 nurses with and without a history of low back pain. BACKGROUND: Disagreement exists regarding the key factors in the aetiology of low back pain. Traditionally workplace loading is viewed as the dominant influence. Data for workplace loading in jobs with non-uniform tasks, however, do rarely exist. METHODS: A three-dimensional inverse-dynamic and force distribution model as well as the respective data acquisition system was used to assess the workplace loading of 12 nurses from surgical departments of two hospitals. The nurses were assigned to two groups based on their history of low back pain (with/without). Workplace loading was measured continuously for 4 h. RESULTS: No differences in workplace loading between nurses with/without a history of low back pain were found. Maximum values of the compressive force at the lumbo-sacral junction were high and well above suggested workplace load limits. High values occurred only during short-time periods (about 0.4% of total shift duration). CONCLUSIONS: A system for the assessment of overall workplace loading has been developed. First results for nurses suggest that critical loadings do exist at the workplace, even so they might not be the decisive factor for the development of low back pain. RELEVANCE: Preventative measures for low back pain in nursing have to include prevention of critical workplace loading. This approach by itself, however, is probably not sufficient.

Adult↗

PubMed1998

Biomechanical evaluation of anterior cervical spine stabilization.

STUDY DESIGN: An in vitro biomechanical study. OBJECTIVES: To simulate a severe compressive flexion injury for determination of the relative stability of different anterior instrumentation systems in a porcine model and to validate this model in human cadaveric specimens. SUMMARY OF BACKGROUND DATA: Anterior plate fixation is useful for high-grade mechanical insufficiency of the cervical spine and may prevent the need for a second procedure. METHODS: The cervical spines of 45 porcine and 12 cadaveric specimens were subjected to nondestructive flexion, lateral bending, and torsional testing on a modified universal testing machine. A corpectomy was performed with release of the posterior ligamentous structures. The specimens were stabilized with one of three anterior plate constructs. The nondestructive testing was repeated to evaluate structural stability (stiffness and neutral zone). Finally, destructive testing examined failure moment, energy to failure, and mechanism of failure. RESULTS: The instrumented specimens had flexural and lateral bending and torsional stiffness values that were similar to or greater than those of their paired intact specimens. The cervical spine locking plate had a significantly higher flexural stiffness ratio (plated:intact), torsional stiffness ratio, lower flexural neutral zone ratio, higher failure moment, and higher energy to failure than did the Caspar plate. CONCLUSIONS: The cervical spine locking plate is theoretically safer than the Caspar system because the posterior vertebral body cortex is not breached by the fixation screws, and the screws are less likely to back out anteriorly and irritate the esophagus. According to these results, the cervical spine locking plate system is biomechanically equivalent to and in some cases more stable than the Caspar system for fixation of a severe compressive flexion injury.

Aged↗

PubMed1997

Trunk muscle fatigue and associated EMG changes during a dynamic iso-inertial test.

This study was designed to investigate the relationship between trunk muscle fatigue and associated changes in the electromyographic (EMG) signals during a dynamic iso-inertial test. Eleven subjects performed dynamic trunk flexion/extension movements against 40% maximum voluntary contraction (MVC) torque until exhaustion in a tri-axial trunk dynamometer. EMG parameters in the time and frequency domain were studied by analysing changes of the signal amplitudes and the spectral density (using the zero-crossing-rate and the median frequency). The kinematics of the movement were analysed according to the movement velocities and the deviations from the required movement plane. The flexion and extension velocities decreased from the beginning to the end of the test. Movement deviations from the sagittal plane into the frontal and transverse plane increased with increasing test duration, as did the EMG amplitude. The median frequency during periods with maximum muscle activity decreased, as did the zero-crossing-rate. The increase in amplitude and decrease in median frequency were more pronounced in the trunk flexors than in the trunk extensors. The parameters of median frequency, zero-crossing-rate and amplitude seem to be sensitive identifiers of muscle fatigue during well-controlled dynamic contractions. While the kinematic data did not yield any information on the mechanisms of the fatigue, changes in the EMG parameters demonstrated that the duration of the test was limited by the fatigue of the trunk flexors.

Adult↗

PubMed1997

The influence of bandage characteristics and inter-individual application variations on underneath bandage pressures.

INTRODUCTION:: Cohesive bandages are applied to the legs of racehorses and horses with limb injuries for protection (prevention of abrasion) and support (reduction of movement at the fetlock joint). The support capacity of all commercially available bandages has been questioned. Consequently, the protection aspect of bandaging and the negative side effects, which can be caused by bandaging (eg pressure induced ischemia with subsequent necrosis), were emphasized. High pressures underneath bandages were shown to cause reduced blood flow. Pressures underneath certain types of bandages were shown to be higher than under others. It is unclear if these differences were due to differences in material characteristics between the bandage types or caused by differences in application by the trainers. The purpose of this study was to determine (a) if differences between different types of bandages are observed if these are applied similarly and (b) if earlier observed differences in pressures underneath bandages are reproducible when wrapped by different trainers. METHODS AND MATERIAL:: (a) A wrapping machine for the application of bandages to an artificial joint (simulating the human knee joint) was designed and built. The machine allows to wrap bandages with adjustable, constant tension under well defined wrapping angles in order to simulate a wrapping technique similar to the wrapping by trainers. The artificial joint is equipped with two pressure sensors (Parotec, Germany). After bandage application, the artificial joint was placed in a specially designed testing machine and cycled through 200 cycles from 0 degrees to 90 degrees of flexion at a frequency of 0.5 Hz. Pressure data were collected at a frequency of 20 Hz. The force required to unwind the bandage from its core was measured with a material testing machine. Five samples each of four different 4" wide cohesive bandages were tested: 'E': high modulus latex, 'V': low mod. latex, 'C': low mod. latex, 'F': medium mod. laminate non-latex. All bandages were applied at manufacturer suggested tensions (50% intercept length). (b) Fifth-three trainers from the Kentucky Horse Center (Lexington, KY) and the Payson Park Training Facility (Indiantown, FL) volunteered for the study. They applied their favoured brand and a type 'F' bandage to an artificial horse limb. Underneath bandage pressures were collected using a pressure mat (Mikro Emed, Novel GmbH, Germany) placed over the fetlock joint. RESULTS AND DISCUSSION:: (a) Maximum pressures during maximum flexion underneath the type 'E' bandage (5.7+/-0.4 N/cm(2)) were significantly higher than for all other bandages (no difference between other bandages, range 3.5+/-0.6 to 4.0+/-0.4 N/cm). The unwinding force for the type 'F' bandage was significantly lower (10.1+/-5.5N) than for all other bandages (range 22.7+/-11.3 to 42.3+/-15.1N). (b) Trainers applied the type 'E' bandage significantly tighter than the other bandages (18.7+/-3.7 N/cm(2) vs a range of 7.5+/-5.4 to 10.4+/-6.1 N/cm(2)); a tendency was observed that the type 'F' bandage was applied looser than the type 'V' bandage. The results of part (b) of this study are consistent with the earlier study. Based on the results of part (a) of this study it can be speculated that (I) The high pressures underneath the type 'E' bandage are clearly due to its material characteristics, and (II) The differences between the other bandages are not caused by material characteristics but probably by the differences in unwinding force. If the unwinding force is higher than the force required to extend the bandage to 50% intercept length, trainers will probably wrap tighter as suggested and desired.

Journal Article↗