Mastiodite masquee: a propos de deux observations

La mastoïdite masquée (MM) se définit comme un état inflammatoire latent de la muqueuse et de l’os mastoïdien avec un tympan normal. Elle est révélée par une complication généralement endocrânienne. Le traitement est une mastoïdectomie associée à une antibiothérapie intraveineuse. Nous rapportons deux observations de mastoïdites masquées dont le diagnostic a été évoqué par l’examen tomodensitométrique qui a rattaché les complications endocrâniennes à leur origine mastoïdienne. Le but de notre travail est de discuter les circonstances diagnostiques, les investigations paracliniques et le traitement des mastoïdites masquées.Mots-clés : mastoïdite masquée, complications endocrâniennes, mastoïdectomie

Carcinome Anaplasique De La Thyroïde: A Propos De 11cas

Introduction : le carcinome anaplasique de la thyroïde est une tumeur rare, mais agressive. Le but de notre travail est d\'étudier les aspects cliniques et de discuter les modalités thérapeutiques de ce cancer. Matériel et méthodes : Il s\'agit d\'une étude rétrospective de 11 cas de carcinomes anaplasiques de la thyroïde colligés et traités au service d\'ORL et de CCF du CHU Farhat Hached Sousse sur une période de 16 ans (1990-2005). Résultats : l\'âge moyen de nos malades était de 60 ans, il s´agissait de 7 femmes et 4 hommes. Les signes de compression locale étaient présents dans 7 cas et l\'examen physique a objectivé un goitre chez 8 malades avec une taille moyenne de 6 cm. L\'atteinte ganglionnaire était observée dans 8 cas et les métastases à distance dans 2 cas. 4 malades ont eu une trachéotomie en urgence avec biopsie thyroïdienne. Les 7 autres malades ont eu une thyroïdectomie totale associée à un curage cervical bilatéral. La radiothérapie a été indiquée dans 10 cas, elle était palliative dans 6 cas. L\'évolution était fatale chez 10 malades avec une survie inférieure à un an. Une seule patiente est en vie, en rémission complète avec un recul de 10 ans. Conclusion : malgré les multiples modalités thérapeutiques envisagées, le pronostic du carcinome anaplasique de la thyroïde reste fâcheux avec une survie ne dépassant qu\'exceptionnellement un an.Introduction: thyroid anaplasic carcinoma of is a rare, but aggressive tumour. Our aim is to study the clinical aspects and to discuss the therapeutic methods of this cancer with great metastatic capacity and bad prognosis. Material and methods: It is a retrospective study of 11 cases of thyroid anaplasic carcinoma treated in the ENT department of Farhat Hached Hospital over one 16 years period (1990-2005). Results: the average age of our patients was 60 years with a female prevalence. The signs of local compression were present in 7 cases and the physical examination objectified a goitre among 8 patients with an average size of 6 cm. Lymph nodes were observed in 8 cases and metastases were noted among 2 patients. 4 patients had a tracheotomy in urgency and 7 other patients had a total thyroïdectomy associated to a bilateral lymph node dissection. The radiotherapy was indicated in 10 cases, palliative in 6 cases. The survival was less than one year for 10 patients. Only one patient is still alive with a complete remission after 10 years of follow up. Conclusion: in spite of the multiple therapeutic methods considered, the prognosis of anaplasic carcinoma of the thyroid is very bad with a survival exceeding rarely a year. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 12-1

Design and analysis of vibration energy harvesters based on peak response statistics

Energy harvesting using cantilever piezoelectric vibration energy harvesters excited by Gaussian broadband random base excitation is considered. The optimal design and analysis of energy harvesters under random excitation is normally performed using the mean and standard deviation of a response quantity of interest, such as the voltage. An alternative approach based on the statistics of the peak voltage is developed in this paper. Three extreme response characteristics, namely (a) level crossing, (b) response peaks above certain level, and (c) fractional time spend above a certain level, have been employed. Two cases, namely the harvesting circuit with and without an inductor, have been considered. Exact closed-form expressions have been derived for number of level crossings, statistics of response peaks and fractional time spend above a certain level for the output voltage. It is shown that these quantities can be related to the standard deviation of the voltage and its derivative with respect to time. Direct numerical simulation has been used to validate the analytical expressions. Based on the analytical results, closed-form expressions for optimal system parameters have been proposed. Numerical examples are given to illustrate the applicability of the analytical results

Electromechanical analysis of an adaptive piezoelectric energy harvester controlled by two segmented electrodes with shunt circuit networks

This paper presents an adaptive power harvester using a shunted piezoelectric control system with segmented electrodes. This technique has spurred new capability for widening the three simultaneous resonance frequency peaks using only a single piezoelectric laminated beam where normally previous works only provide a single peak for the resonance at the first mode. The benefit of the proposed techniques is that it provides effective and robust broadband power generation for application in self-powered wireless sensor devices. The smart structure beam with proof mass offset is considered to have simultaneous combination between vibration-based power harvesting and shunt circuit control-based electrode segments. As a result, the system spurs new development of the two mathematical methods using electromechanical closed-boundary value techniques and Ritz method-based weak-form analytical approach. The two methods have been used for comparison giving accurate results. For different electrode lengths using certain parametric tuning and harvesting circuit systems, the technique enables the prediction of the power harvesting that can be further proved to identify the performance of the system using the effect of varying circuit parameters so as to visualize the frequency and time waveform responses

Design, analysis, and feedback control of a nonlinear micro-piezoelectric–electrostatic energy harvester

A nonlinear micro-piezoelectric–electrostatic energy harvester is designed and studied using mathematical and computational methods. The system consists of a cantilever beam substrate, a bimorph piezoelectric transducer, a pair of tuning parallel-plate capacitors, and a tip–mass. The governing nonlinear mathematical model of the electro-mechanical system including nonlinear material and quadratic air-damping is derived for the series connection of the piezoelectric layers. The static and modal frequency curves are computed to optimize the operating point, and a parametric study is performed using numerical methods. A bias DC voltage is used to adapt the system to resonate with respect to the frequency of external vibration. Furthermore, to improve the bandwidth and performance of the harvester (and achieve a high level of harvested power without sacrificing the bandwidth), a nonlinear feedback loop is integrated into the design

New materials and devices for preventing catheter-related infections

Catheters are the leading source of bloodstream infections for patients in the intensive care unit (ICU). Comprehensive unit-based programs have proven to be effective in decreasing catheter-related bloodstream infections (CR-BSIs). ICU rates of CR-BSI higher than 2 per 1,000 catheter-days are no longer acceptable. The locally adapted list of preventive measures should include skin antisepsis with an alcoholic preparation, maximal barrier precautions, a strict catheter maintenance policy, and removal of unnecessary catheters. The development of new technologies capable of further decreasing the now low CR-BSI rate is a major challenge. Recently, new materials that decrease the risk of skin-to-vein bacterial migration, such as new antiseptic dressings, were extensively tested. Antimicrobial-coated catheters can prevent CR-BSI but have a theoretical risk of selecting resistant bacteria. An antimicrobial or antiseptic lock may prevent bacterial migration from the hub to the bloodstream. This review discusses the available knowledge about these new technologies