ITBM-RBM最新文献

Bone substitutes are more and more used in bone surgery for their biologic safety, clinic efficiency and facility to synthesize. However many devices are actually marketed which are not similar according to their theoretical composition. We did not find any comparative physicochemical or clinical study which allows to evaluate them. The aim of this study is to compare with the same analysis methods the physicochemical properties of 14 marketed materials (blocs and granules). X-ray diffraction and infrared spectroscopy were used for components determination. Secondary electron microscopy (SEM) was performed for porosity measurements and micro-indentation method was applied to determine the elastic limits. At last a dissolution test was performed. The results have shown that the composition is likely those claimed by manufacturers excepted for one material. However mineral impurities were detected in some substitutes. All materials are not macroporous (some of them have macroporosity less than 30%). Moreover we observed a large diversity between materials (macroporosity comprised between 30 and 60%). Micro-indentation method allowed to characterize three groups of substitutes (elastic limit lower than 10 MPa, comprised between 30 and 40 MPa, upper 100 MPA). Results from dissolution experiments did not show any correlation with theoretical composition. This study shows that all materials have a nearby composition. The macroporosity and mechanical properties are not similar according the several studied substitutes. However these last properties have a great influence on the osseous integration and it would be on interest to perform some clinical comparative study with these bone substitutes.

Analysis of speech has become a popular non-invasive tool for assessing the speech abnormalities. Acoustic nature of the abnormal speech gives relevant information about the type of disorder in the speech production system. These signals are essentially non-stationary; may contain indicators of current disease, or even warnings about impending diseases. The indicators may be present at all times or may occur at random — during certain intervals of the day. However, to study and pinpoint abnormalities in voluminous data collected over several hours is strenuous and time consuming. Therefore, computer based analytical tools for in-depth study and classification of data over daylong intervals can be very useful in diagnostics. This paper deals with the classification of certain diseases using artificial neural network, and then analyzed. This analysis is carried out using continuous wavelet transformation patterns. The results for various types of subjects discussed in detail and it is evident that the classifier presented in this paper has a remarkable efficiency in the range of 80–85% of accuracy.

The preferred assessment of bone biomechanical competence in vitro is by direct mechanical testing and in vivo by X-ray absorptiometry techniques. For more than 30 years investigators have been developing alternative techniques, by ultrasonic methods, aimed at providing (i) the elastic properties in vitro without the complications related the destructive character of mechanical testing and (ii) the evaluation of the fracture risk in vivo, taking benefit of the propagation of elastic wave which are inherently affected by both material and structural bone properties. The in vitro strategy includes the use of multiscale ultrasonic assessment for the combined evaluation of both the material (or intrinsic) and the structural elastic properties in various axes of symmetry. The in vivo approach involves the use of the different propagation modes (bulk wave, guided wave, surface wave) permitted by the ultrasonic approach. We will review the in vitro and clinical data on each ultrasonic approach and discuss potential areas of development in the field of quantitative bone assessment bone.

Because of the rise in life expectancy and in the prevalence of age-related diseases, the population in long-term care institutions is increasing. Among them are patient who shout. These put to the test the nursing staff. A quarter of the patients in long-term care institutions shout at least 4 times a week. The shouting and screaming may be intense and represent a real burden for the staff. In spite of this, shouting remains little studied while it is recognized as a disturbing phenomenom. The quiritachronometer is a detecting system, which records the duration of the shouting and restlessness of a bed-ridden patient. On one hand, a microphonical sensor is set to detect when a sound threshold is crossed and on the other hand, a passive infrared dispositive registers the movements in the bed. The artificial intelligence of the analysing software treats the data and displays the results in the shape of a circular 24-hours'diagram. The data thus collected are transmitted to the medical staff who can then adapt the treatment to the patient's state. The quiritachronometer has been compared to the evaluation results put forward by the specialized staff of a long term-care hospital unit. Confronting results from both methods, experts have agreed and validated, unanimously, the quiritachronometer. Through the example of a medical case, we could show the praticality and medical interest of the quiritachronometer in the evaluation of the treatment and the diagnosis of the shouting in a patient with cognitive impairments and communication hindrance.

High frequency electrical stimulation by means of electrodes implanted into the brain has become an accepted technique for treatment of Parkinson's disease. The electrical field distribution normally inserted into the sub thalamic nucleus minimise abnormal brain activity. Square wave pulses of 1–3.6 V with duration of 60–90 μs at a frequency range of 130–185 pps are generally used. Every electrode unit consists of four cylindrical electrodes positioned in a row and can be switched on independently. This paper determines the contact impedance of the electrodes for different frequencies and proposes improvement to reduce the contact impedance between the electrodes and the brain. Measurements were performed by placing the electrodes in a tank filled with saline. Different frequencies were applied on two electrodes via a resistor. The current was measured through the resistor and the voltage was registered between one of the electrodes and a third non current carrying electrode. The obtained values were used to calculate the contact impedance. The result shows large contact impedance for the used frequency compared to the impedance of the treated tissue, which means that variation in contact impedance can result in variation in the electrical field applied to the tissue.