Search

Resume Introduction L’administration des medicaments par sonde de nutrition enterale est une potentielle source de iatrogenie en raison du probleme de formes galeniques non adaptees. Objectifs Analyser les prescriptions des patients sous nutrition enterale afin de determiner si les formes galeniques prescrites etaient compatibles avec ce mode d’administration. Observer et evaluer les pratiques d’administration de ces medicaments par les infirmieres. Patients et methodes Nous avons prospectivement analyse 30 prescriptions de patients sous nutrition enterale par sonde gastrique dans le service de reanimation medicale de l’hopital universitaire Habib Bourguiba de Sfax. Nous avons observe et evalue les pratiques des infirmieres lors de la preparation et l’administration de medicaments a ces patients par sonde de nutrition enterale. Resultats Seuls 12 % des formes prescrites etaient liquides. Quatre-vingt-huit pour cent de ces medicaments ont ete broyes et les capsules ont ete ouvertes avant administration. Les formes galeniques etaient non conformes dans 22 % des cas (forme gastro-resistante pulverisee, administration de formes injectables avec risque d’irritation…). Sur les 78 medicaments administres par dix infirmiers differents, le temps entre le passage du medicament et celui de la nutrition enterale n’a pas ete respecte dans 56 % des observations, les medicaments ont ete melanges et administres en une seule fois dans 90 % des cas. Les gants ont ete portes dans 20 % des observations. Le rincage de la sonde n’a pas ete effectue entre des administrations consecutives ou avant chaque administration dans 100 % des observations. Conclusion Cette etude met en evidence le risque d’erreur lie a l’administration des medicaments par sonde de nutrition. La cooperation avec le pharmacien est necessaire afin de proposer des solutions par le choix de forme galenique adaptee ainsi que par la redaction de procedures d’administration.

Cosmetic or pharmaceutical composition containing superoxide dismutase (SOD) was usually used in topical administration, particularly, in fighting against skin ageing and in the protection of the skin against radiation exposure. Mesembryanthemum crystallinum is a halophyte plant widely used in the traditional medicine, characterized by the presence of anti-oxidants enzymes in responses to abiotic stresses. In the present study, we prepared a formulation with M. crystallinum extract characterized by naturally occurring SOD and catalase in association with other anti-oxidants molecules. The SOD activity was measured by 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl-tetrazolium bromide/riboflavin method, catalase by colorimetric method and the total anti-radical activity was measured by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) method. Formulations contain a significant SOD activity (8.33 U mg(-1)), a catalase activity (0.5 x 10(7) UC) and an anti-radical activity (30% of DPPH inhibition). The formulation storage (15 days at 4 degrees C) showed a marked loss of total anti-oxidant capacity. The addition of the M. crystallinum extract induced also a reduction in formulation viscosity and pH.

Most existing MIMO (multiput-input multiput-output) schemes optimize only either the diversity gain or the multiplexing gain. To obtain a good tradeoff between these two, the quasi-orthogonal group space-time (QoGST) architecture is proposed, wherein the transmit stream is subgrouped but encoded via an inter-group space-time block encoder, with group interference suppression at the receiver. This paper also considers another combined space-time coding and layered space-time architecture, which we refer to as group layered space-time (GLST), where space-time block coding is employed within each group. Under the assumption of Rayleigh fading and a prior perfect channel state information at the receiver, a performance analysis will demonstrate that both QoGST and GLST can achieve a good diversity-multiplexing tradeoff. QoGST is even superior to GLST. Simulation results will validate our analysis and further show that compared to the existent layered space-time block code (LSTBC) scheme, both QoGST and GLST can achieve a significant performance gain.

Link adaptation allows the transmitter to adapt to changing channel conditions. Critical to the design of link adaptation is the accuracy of channel state information at the transmitter. In this paper, we investigate the effect of imperfect channel state information and feedback delay on the performance of a multiple-input multiple-output zero-forcing receiver with adaptive power allocation. A closed-form approximate upper bound on bit error rate is derived for M-ary phase shift keying and M-ary quadrature amplitude modulation and it is valid for arbitrary numbers of transmit and receive antennas. Comparison with Monte Carlo simulations is also provided, showing that the results derived from this analytical bound are useful for system design

Spironolactone is a steroidal diuretic showing incomplete oral behaviour because of its low solubility and slow dissolution rate. In this study, we applied the nanoprecipitation method to prepare spironolactone-loaded nanocapsules, at laboratory-scale and pilot-scale. The effect of several formulation variables on the spironolactone-loaded nanocapsules properties (average size, drug release rate and drug entrapment) was investigated. The optimized formulations at laboratory-scale and pilot-scale lead to the preparation of spironolactone-loaded nanocapsules with a mean size of 320 and 400 nm, respectively, a high encapsulation efficiency (96.21% and 90.56% respectively), both stable for 6 months. The release of spironolactone from nanocapsules was rapid and complete in a simulated gastric fluid, therefore recourse to spironolactone nanoencapsulation should enhance its oral bioavailability and probably its efficiency. The optimized formulations lead to a high drug-concentration in the liquid preparation (1.5 mg/ml) allowing minimizing the preparation volume administered for children medication.

In this paper, we consider a multiuser multiple input multiple output (MIMO) CDMA system where each user is transmitting different streams spread with the same code on a set of multiple antennas. Signals from one user are received as one group and each user is thought of as a virtual group. At the receiver, group ordered successive interference cancellation detection is applied. Optimal and sub-optimal group detection orders that maximizes the system performance are then derived. Various linear group detectors are considered such as the linear decorrelators and a closed form expression of the optimal order is given for the case of each of these group detectors. Numerical results demonstrate significant gains in the system performance as well as the importance of group ordering

Group layered space-time architecture (GLST) combines space-time block coding and layered space-time processing, where the transmit stream is partitioned into different groups, and in each group, space-time block coding is applied. In the traditional receiver of GLST, group detection is applied first to suppress the interference from other groups, and then decoding is performed for the desired group. In this letter, a novel detector is proposed in which the entire groups are decoded first, and then group detection is performed next. Theoretical analysis will demonstrate that the new detector can achieve a significant capacity gain compared with the traditional one. Simulation results will further show that the proposed detector can obtain at least 4 dB gain at a frame-error rate of 10/sup -2/, for instance.

It is well known that multiple-input multiple-output (MIMO) systems provide two types of gains: diversity gains and spatial multiplexing gains. Recently, a tradeoff function of these two gains has been derived for a point-to-point MIMO system when optimal detection is used. In this paper, we extend the previous work to a more general MIMO system, where the transmitted data is coded in groups. Group detection is applied at the receiver to retrieve the data. It consists of a zero-forcing decorrelation that separates the groups, followed by a joint detection for each of the groups. Two receiver structures are considered in this paper; namely, group zero forcing (GZF) and group successive interference cancellation (GSIC). We assess the diversity-multiplexing tradeoff function of each of these receivers over a richly scattered Rayleigh fading channel. Three rate-allocation algorithms will be considered here; namely, equal rate, group-size proportional rate, and optimal-rate allocation. An explicit expression of the system tradeoff will be derived for both receivers with these three rate allocations. The obtained results will first be optimized over all possible group partitions for a given number of groups. Next, the number of groups will be varied to further optimize the system-tradeoff performance. An overall optimum tradeoff for a general MIMO system with group detection will then be obtained. Numerical results will indicate that optimum performance can be approached with very-low-complexity schemes for a wide range of data rates. It will be also demonstrated that group detection bridges the gap between the traditional decorrelator and the optimal receiver tradeoff performances.

We consider the transmission of K binary phase-shift keying signals over M diversity channels through a rich scattering environment. Improved group detection rules are proposed to mitigate the effect of the improper multiaccess interference, and an enhancement of the system receive diversity order is shown to be obtained. For example, it is demonstrated that a further gain of |g~|/2 per group is obtained compared with conventional group detection, where |g~| is the interfering group size. In addition, when there is only one antenna per group, the considered receiver with the improved detection rules is equivalent to the decorrelator. In this case, it is shown that (K-1) interferers can be nulled out, and that an M-(K-1/2) receive diversity order is achieved, compared with only M-/sup 2/K+1 with the conventional detection rules. Numerical results will further put in evidence such gains.

In this paper, we investigate the use of layered space-time (also known as the vertical Bell Laboratories layered space-time (V-BLAST) scheme) for multiuser detection in fading channels. The multiple transmit antennas in V-BLAST are treated as individual mobile station transmitters, while the base station consists of multiple receive antennas. In the proposed system, users are organized in groups and allocated a unique spreading code within the same group. Using these codes, we are able to separate the different groups, and layered space-time algorithm is then invoked to further remove the remaining interference between users. A decorrelator-type receiver-based layered space-time detection is proposed for both complex and real constellations. For the latter case, we derive our receiver after evaluating and comparing the performance of two decorrelators based on the V-BLAST scheme. It is demonstrated that a significant performance improvement and increase in system capacity is obtained with very low spreading factors. Further results are also introduced by considering reduced complexity receivers based on serial layered space-time group multiuser detection, and parallel layered space-time group multiuser detection.

Citrulline is an amino acid that becomes essential in situations of intestinal insufficiency such as short bowel syndrome. It is therefore interesting to provide the patients with dosage forms for routing citrulline to the colon. The aim of this work is to formulate microspheres of citrulline for colonic targeting by the technique of spray drying.Eudragit(®) FS 30D was selected as polymer to encapsulate citrulline using the spray drying technique. Citrulline and Eudragit(®) FS 30D were dissolved in water and ethanol, respectively. The aqueous and the ethanolic solutions were then mixed in 1:2 (v/v) ratio. Microspheres were obtained by nebulizing the citrulline-Eudragit(®) FS 30D solution using a Mini spray dryer equipped with a 0.7mm nozzle. The microspheres have been formulated using citrulline and Eudragit(®) FS 30D. The size distribution of microspheres was determined by light diffraction. The morphology of the microspheres was studied by electron microscopy. Manufacturing yields, encapsulation rate and dissolution profiles were also studied.The microspheres obtained had a spherical shape with a smooth surface and a homogeneous size except for the microspheres containing the highest concentration of polymer (90 %). The formulation showed that the size and morphology of the microspheres are influenced by the polymer concentration. Manufacturing yields were about 51 % but encapsulation rate were always very high (above 90 %). The in vitro dissolution study showed that the use of the Eudragit(®) FS 30D under these conditions is not appropriate to change the dissolution profile of the citrulline.This technique has led to the formulation of microspheres with good physical properties in terms of morphology and size. The compression of the microspheres should help to control citrulline release for colonic targeting.

Drugs' administration via feeding tubes is a potential source of iatrogenic events for the intensive care patients because of the problem of not adapted galenic forms.We analyzed the prescriptions of patients with enteral feedings to determine if the galenic forms were compatible with administration via feeding tubes. We also observed and analyzed the methods of drugs passage by nurses.We analyzed 30 prescriptions of patients with enteral feedings in the intensive care unit of Habib Bourguiba Sfax hospital, by a prospective and exhaustive way. We also, observed and evaluated the practices of preparation and administration of drugs to these patients via feeding tube by nurses.Only 12% of drugs were liquids. Eighty-eight percent of the drugs were pulverised and capsule open before administration. The galenic form was not in conformity for 20% of drugs because of the prohibition to crushing tablet or opening capsule (gastroresistant form was dissolved), or because of the administration of a parenteral form (risk of irritation). Among 78 drugs administered by 10 different nurses, the time between passage of the drug and enteral nutrition were not respected for 59% of the observations. The drugs were managed in mixture for 90% of the observations. The gloves were not worn in 80% of observations. No rinsing is made between consecutive administrations and before administration.This study shows that it is possible to reduce risk of administration errors in the intensive care unit and to facilitate the administration of drug via feeding tube by prescribing liquid oral form or soluble solid oral form. It also shows the need for cooperation with the pharmacist in order to adapt the galenic forms and to redact protocol of administration.

Background: The aim of the present study is to establish age- and sex-related reference ranges of serum IGF-I and IGF binding protein-3 (IGFBP-3) levels in a pattern of Tunisian children. Subjects and methods: Two hundred healthy Tunisian children (103 boys and 97 girls), aged between 6 and 16 yr, were considered in the study. Results: Mean serum levels of IGF-I and IGFBP-3 are observed to be higher in girls compared to boys of the same age interval. However, these differences were statistically significant only in pubertal ages (11–14 yr) for IGF-I and in pre-pubertal ages (6–10 yr) for IGFBP-3 (p

We consider a collaborative wireless distributed network, consisting of one source transmitting information to a remote destination in the presence of N relay nodes. We assume that all nodes have similar capabilities, are randomly distributed geographically, immersed in the clutter and close to the ground, each employing a single antenna. Assuming a Decode-and-Forward technique, we propose various collaborative approaches for signaling. Using well-known channel coding techniques, the destination is not able to start decoding its intended message until all nodes have decoded the entire message. Using more sophisticated coding techniques, the destination can start decoding the transmitted message at the start of the communication by the source. Various ways of organizing the relay collaboration are: Generalized Beamforming; Generalized Alamouti; and Simultaneous Casting. We then evaluate the performance of these collaborative approaches by simulations, employing an appropriate fading/path loss channel model. Obtained results will demonstrate the superiority of the sophisticated coding technique used and provide insights on when collaboration in networked multiple antennae systems is useful. Specifically, a gain of the order of 9 dB in the required transmit power is achieved assuming Simultaneous Casting and 0 dB transmit power per node, compared to the case when these sophisticated codes are not used. Finally, we also observe a gain in the system 10th percentile outage rate on the order of 1.4 bit/s/Hz at a 0 dB transmit power and with Generalized Beamforming, compared to the case where relays are not used.

We consider a compact multiple-input multiple-output (MIMO) system where antenna elements are placed linearly and side by side in a limited size array. Inevitably, both mutual coupling and spatial correlation effects have a strong presence in such system. We then investigate the performance of both hard and soft antenna selection in such conditions using Monte Carlo simulations. Our results indicate that soft selection could always achieve superior performance as compared to the hard selection even given the presence of mutual coupling. Our results will further conclude on the applicability range of antenna selection schemes.

The Human Genome Project improves our understanding of the molecular genetics basis of the inherited and complex diseases such as diabetes, schizophrenia, and cancer. Information from the human genome sequence is essential for several antenatal and neonatal screening programmes. The new genomic tools emerging from this project have revolutionized biology and medicine and have transformed our understanding of health and the provision of healthcare. Its implications pervade all areas of medicine, from disease prediction and prevention to the diagnosis and treatment of all forms of disease. Increasingly, it will be possible to drive predisposition testing into clinical practice, to develop new treatments or to adapt available treatments more specifically to an individual's genetic make-up. This genomic information should transform the traditional medications that are effective for every members of the population to personalized medicine and personalized therapy. The pharmacogenomics could give rise to a new generation of highly effective drugs that treat causes, not just symptoms.

We consider a receive antenna selection MIMO system, where only one receive antenna is selected out of Nr antennas. Spatial channel correlation will be considered at the receiver side only. We investigate here the capacity performance of such a system. In particular, we derive a closed-form expression of its outage probability expressed in an infinite series representation. To do so, we derive the joint cumulative distribution function and joint probability density function of the squared row norms of the channel matrix by using the statistical properties of multivariate chi-square random variables. Our simulation results will be shown to validate our analytical findings.

In this paper we consider a system in which multiple dipole antennas are placed side-by-side within a finite space at the receiver to form a uniform linear array, causing the dipole antennas to be closely spaced. We investigate the achievable rate with receive antenna selection and take into account both spatial correlation and mutual coupling effects between the antennas. We assume the full channel state information is available at the receiver but not at the transmitter. Opposite to what might be expected, the system achievable rate with receive antenna selection can outperform the system employing all the antennas, provided the number of antennas used is larger than a critical value. We also describe the optimal processing scheme which enumerates all possible antenna combinations and selects the combination maximizing the instantaneous achievable rate for a given channel realization.

In this study we propose a new architecture named VIP (VHE in mobile IP networks) which guarantees authorized user access and user mobility management. The main goal is to bring the VIP architecture closer to the current GSM networks. To achieve this goal our architecture is based on LDAP and RADIUS services. VIP is able to ensure user's mobility across different IP domains. For the transportation of personalized services across different networks VHE (Virtual Home Environment) is employed. VHE gives a set of recommendations for providing users their home environment in foreign networks. The VHE services are activated to transport the user's profile between the home and the foreign network. Index Terms—VHE, Roaming, IEEE 802.11, Security

Mobility management is an important topic in wireless networks. Mobile hosts are subject to changing their point of attachment from his home network to another foreign network. In terms of personalized services, the network manager must know the user location by implementing a roaming mechanism. VHE (virtual home environment) provides to the users an identical computing network environment in a foreign network to the one in their home network. In this paper we propose an architecture that ensures authorized user access and user mobility management. This architecture also guarantees the management of personalized services of the user according to the VHE specifications. We introduce a new concept named "mobility service provider" (MSP) which manages user mobility. The mechanisms for user authentication, management and update of the user profile, are based on LDAP (lightweight directory access protocol) services. For authorized user access, RADIUS (remote access dial in user service) security services are used. Additionally to user authentication, the main goal is service adaptability regardless of the equipment utilized. The VHE services are able to convey the user's profile between the home and foreign network. We present in this paper an architecture that supports user mobility.

Multiple-input multiple-output (MIMO) systems can provide two kinds of gain: diversity gain and multiplexing gain. Most existing MIMO schemes, including space-time coding and layered space-time, aim at maximizing either of them. Therefore, it is desirable to design a scheme to get a better tradeoff between the multiplexing gain and diversity gain. In this paper, a novel quasi-orthogonal group space-time (QOGST) architecture is proposed. In QOGST, the transmit stream is divided into several groups and all the groups are encoded via an inter-group space-time block encoder. Group interference suppression is adopted at the receiver. Performance is evaluated in terms of symmetric energy and it is shown that compared to the group layered space-time (GLST) architecture, the proposed QOGST can achieve a higher symmetric energy and a better diversity-multiplexing tradeoff. Simulation results validate our analysis and show that QOGST can achieve at least 3 dB gain over GLST at a FER of 10/sup -3/, for instance.

Summary form only given. VHE (virtual home environment) poses new challenges in terms of services customization and the integration of end-to-end QoS management. Our approach provides a model for the mobility management in IPv6 according to VHE context. In this paper we introduce an architecture which guarantees authorized user access and user mobility management. The mechanism used for user authentication is based on LDAP (lightweight directory access protocol) and RADIUS (remote access dial in user service) services, giving accurate localization of the mobile node even in the presence of hadover; at this point, the user must be re-authenticated and consequently the VHE services are activated to transport the user profile to the foreign network.

The aim of this work was to study theophylline dissolution and diffusion from a compressed ethylcellulose matrix through an artificial membrane. The sustained release tablets were manufactured manufactured by direct compression. Dissolution and diffusion studies were performed using an absorption simulator. In the donor compartment, different pH media were used: i) 1.2, 5, 6, ii) the same media supplemented with 10% glucose and iii) an amino acid medium. The receiver medium was held at pH 7.4. The Higuchi equation was used to elucidate the dissolution mechanism. Results showed that dissolution was mainly influenced by theophylline solubility with a mechanism based on diffusion. Diffusion rate was assessed by calculating the diffusion coefficients. Diffusion was essentially dependent on rate of theophylline release.

In this paper, we propose an improved pre-combining group detection in the presence of improper multi-access interference (MAI). We consider a transmission of K BPSK signals over M diversity channels in rich scattering environments. The different received signals are grouped at the receiver, and detected jointly in groups using maximum likelihood (ML) detection. The novelty of the proposed scheme consists in the proper use of the information contained in the MAI statistical properties. We show that the proposed receiver achieves higher diversity order gains than conventional group detectors. For example, a gain of the order of |G~|/2 is obtained for the group G compared with the conventional receiver, where |G~| is the interferers number. Particularly, when the group size is one, the proposed receiver is equivalent to a decorrelator that can null out (K-1) interferers while providing a diversity order of (M- (K-1/2) for each signal. Exact pairwise-error probability along with bounds for the bit-error rate are derived for each group. Numerical results will also show that optimum performance is closely approached when the proposed architecture is used.

Summary form only given. The aim is to present our adaptation model an adaptation strategy for UMTS multimedia services. The purpose of this strategy is to classify and then select service flows which are to be adapted in priority according to policies and strategic orientations laid down by the operator. Policies are specified according to factors which we defined. Fuzzy logic is used for the implementation of this strategy as it represents a natural reasoning mode useful to decide which commercial service adaptation policy is to be carried out according to resource use context.

We propose in this paper a novel group detection scheme that we denote by group ordered successive interference cancellation (GOSIC) multiuser detector. We consider a multiuser MIMO CDMA communication system, where each user carries more than one antenna, but is assigned only one spreading signature. Users are then considered as virtual groups. Our proposed receiver consists of ordering these users at the receiver side in order to maximize the overall system performance, and carrying group detection for each one using layered space-time processing. We define and derive the optimal user order based on the group signal to noise ratio (GSNR), and show that not only it is optimal in this sense but also in the sense of asymptotic symmetric energy. We also propose another sub-optimal order in order to overcome the complexity issues. Finally, we compare the performance of our proposed receivers with traditional group serial interference cancellation and conventional layered space-time multiuser architectures, and show that significant improvement is introduced.

Multiple-input multiple-output (MIMO) systems can provide great capacity improvement but suffer from multiple expensive RF chains. Antenna selection offers a good tradeoff between complexity and performance. This paper addresses the problem of optimal receive antenna selection in correlated channels. We consider the transmission of M independent signals to a base station with N correlated antennas and present two criteria for selecting the optimal L out of N receive antennas in terms of capacity maximization or BER minimization, assuming that only the long-term channel statistics, instead of the instantaneous channel state information, are known. Simulations will validate our theoretical analysis and demonstrate that within a rather wide angular spread range, the number of required RF chains can be significantly decreased using our proposed selection strategy while achieving very close performance to the instantaneous antenna selection system and the conventional MIMO system without antenna selection.

This paper assesses the impact of layered space-time multiuser detection (LAST-MUD) in wireless circuit switched and packet switched modes integrated CDMA systems. The network is hence composed of packet and circuit radio mobile stations transmitting to an antenna array at the base station receiver. These users are organized in different groups and users in a particular group are allocated the same spreading code. Therefore, the CDMA spreading technique will remove the interference between the groups and the layered space-time scheme will further remove the remaining interference between users. The effect of packet mode users on system performance is considered. Throughput and BER performances of packet and circuit mode users are hence investigated, respectively. The robustness of the LAST-MUD is also demonstrated against transmission power variation of packet mode users.

The upcoming 3/sup rd/ telecommunication telephony generation is setting forth a new set of challenges in the development and deployment of numerous telecom services which follow the requirements and expectations of end-users. This paper describes our approach to provide the user with an environment to set up his own preferences when using such multimedia telecom services. Our purpose is to keep services, profiles and behaviors unchanged and just compose them in a safe way in purpose to generate added value services that answer to the end user expectations. The first implementation is provided and tested on Web applications where we integrate the user profiles with no modification on the XML document. In particular we describe how we adapt the representation according to the end-user requirements. Then we extend our approach to a more flexible system. Our purpose was to provide an environment for end-user QoS control of multimedia telecom services that integrate behavior as well as profiles. We also present our evaluation of the approach that has been realized and the future study.

In this paper, we investigate the use of layered space-time scheme, known as V-BLAST, for multiuser detection over the uplink of a DS/CDMA communication system. The multiple transmit antennas in V-BLAST are treated as individual mobile station transmitters, while the base station consists of multiple receive antennas. The layered space-time algorithm is then invoked to detect the signals from all users. In addition, CDMA is also applied. Groups of users are arranged and allocated the same signature sequence or spreading code. The groups of users are first separated using the group spreading codes, and the layered space-time detection algorithm is then invoked to further remove the remaining interference. It is demonstrated that a significant performance improvement and increase in system capacity are obtained with very low spreading factors.

We assess the impact of layered space-time detection technique, known as V-BLAST, for multiuser detection over a packetized random access system based on CDMA and slotted Aloha. In this scheme, the multiple transmit antennas are treated as individual packet radio mobile stations, while the base station consists of multiple receive antennas. In addition, users are arranged in groups and allocated the same group signature sequence. The spreading technique is hence used to separate between the groups, and the layered space-time algorithm is then invoked to detect the signals from all users transmitting packets at the same time. A significant improvement in system throughput, delay and capacity are achieved.

ALOHA systems are some of the most attractive options for wireless applications which include packet transmission. However, despite their flexibility and simplicity, they present a very low channel throughput. The objective of this paper is to analyze the performance of such a protocol based layered space-time scheme over wireless communication links. A multiuser environment is hence considered in which each user carries only one transmit antenna. A generalization of Vertical-Layered Space-Time (V-BLAST) technique for BPSK modulation is then invoked to detect the transmitted signals through the use of multiple receive antennas at the base station. We asses in this paper the gain achieved by the proposed receiver; denoted by rT-BLAST, compared to the conventional V-BLAST system. We first consider the performance of this system over flat fading channels for a variety of system parameters. Then, throughput and delay performance are analyzed under different packetized traffics. It is demonstrated through simulation results that a significant improvement in system capacity, throughput and delay are achieved.

Objectifs A travers deux observations et une revue de la litterature nous allons insister sur l’importance du diagnostic et la prise en charge precoce de la dilatation kystique congenitale des voies biliaires. Sujets Nous rapportons deux observations de nourrissons de sexe feminin, hospitalises au service de chirurgie pediatrique de l’hopital Habib Thameur de Tunis. Resultats Le premier nourrisson âge de 17 mois, etait opere en urgence devant un tableau de peritonite. L’exploration peroperatoire a objective une peritonite biliaire en rapport avec un kyste du choledoque perfore. Il a eu une cholecystectomie avec une fermeture de la perforation sur un drain de kehr. Il a ete opere apres un mois et a eu une resection du kyste avec anastomose bilio-digestive. Les suites operatoires etaient simples. Le deuxieme nourrisson âge de 4 mois, a eu la meme prise en charge, sauf que chez ce dernier le diagnostic de dilatation kystique congenitale des voies biliaires a ete pose une semaine avant la perforation. Conclusions La dilatation kystique congenitale des voies biliaires est une malformation rare. Son diagnostic est de plus en plus precoce grâce au progres de l’imagerie. Une prise en charge therapeutique precoce est donc necessaire pour eviter une complication grave a savoir sa perforation.

Objectifs La tumeur rhabdoide renale est une tumeur agressive et extremement rare chez l’enfant. A travers de deux cas, nous rappelons ses particularites diagnostiques et ses modalites therapeutiques. Sujet / materiels et methodes Nous rapportons deux observations colliges au service de chirurgie pediatrique de l’hopital Habib Thameur de Tunis. Resultats principaux Observation n°1:garcon âge de 14 mois, presentant une masse abdominale. Le bilan radiologique a evoque le diagnostic de nephroblastome avec la presence de metastase pulmonaire. Une chimiotherapie neoadjuvante a ete instituee puis une nephrectomie droite a ete realisee. L’examen histologique etait en faveur d’une tumeur rhabdoide du rein. Malade a eu 3 autres seances de chimiotherapie. Le recul est de 3 mois. Observation n°2: garcon âge de 20 jours avec diagnostic antenatal d’une masse renale gauche. Le bilan radiologique etait en faveur d’une tumeur renale avec metastases hepatiques et osseuses. Une chirurgie premiere par nephrectomie a ete effectuee. L’histologie avait conclu a une tumeur rhabdoide du rein avec. Le recul est de 15 jours. Conclusions La tumeur rhabdoide renale est une tumeur rare, extremement agressive. Son traitement n’est pas bien codifie et son pronostic demeure sombre.

Objectif Le carcinome a cellules claires(CCC), bien que entite rare de l’enfant, doit faire partie des diagnostiques differentiels. Nous precisons notre demarche diagnostique et notre conduite a tenir, a propos d’un cas de (CCC). La rarete de cette pathologie chez l’enfant et l’evolution favorable justifient cette presentation. Resultats On vous presente l’observation d’un garcon, âge de 14 ans, sans antecedents pathologiques particuliers, qui a presente des lombalgies gauches et une hematurie totale. L’echographie a montre une masse echogene heterogene, polaire superieure renale gauche avec des micro calcifications. On porte le diagnostique d’une tumeur renale probablement maligne et on opte pour un traitement chirurgical. Le garcon a eu une nephrectureterectomie gauche elargie. L’etude anapatomopathologique de la piece a conclu a un (CCC) grade 1 de Furhmann, TNM T1a, stade 1 de Robson. L’enfant n’a eu aucun traitement adjuvant. Le recul a 12 ans post operatoire ne montre pas de recidive tumorale. Conclusion Bien que rare chez l’enfant(

Objectifs Le syndrome de Peutz-Jeghers est une affection autosomique dominante rare, associant une lentiginose a des hamartomes digestifs et comportant un risque d’association a des cancers. A travers une nouvelle observation, nous rappelons ses particularites diagnostiques et ses modalites therapeutiques. Sujet / materiels et methodes Nous rapportons une nouvelle observation colligee a l’hopital Habib Thameur de Tunis. Resultats principaux Garcon âge de 12 ans, aux antecedents d’anemie recidivante mal suivie, opere pour appendicite aigue a l’âge de 5 ans. Il presentait un Melena depuis 2 semaines. L’examen physique trouve une pâleur cutaneo-muqueuse et un melena au toucher rectal. Les differentes explorations ont conclu a un diverticule de Meckel. Les constatations per operatoire ont montre un diverticule de Meckel associe a plusieurs polypes au niveau du grele avec un nodule blanchâtre sur son bord mesenterique. Le malade a eu une resection anastomose. L’histologie a conclu a une polypose hamartomateuse de grele. Les suites operatoires etaient simples avec un recul d’un an. Conclusions Le syndrome de Peutz-Jeghers est une affection rare. Une surveillance est necessaire a fin de detecter des cancers associe qui determine le pronostic.

BackgroundThe PTEN tumour suppressor gene is frequently inactivated in a wide range of cancers and encodes a nonredundant phosphatase which antagonizes the PI3K signalling pathway. Previous IHC analysis and genomic characterization (through BAC CGH array) of a series of 135 sporadic breast carcinomas identified some tumours with decreased or absent PTEN levels and/or loss at 10q23.3, including the PTEN locus. Comprehensive molecular genetic analysis of PTEN, in addition to PI3KCA and TP53 point mutation screening were performed on this large homogenous series of breast carcinomas, giving a molecular portrait of key players of sporadic breast carcinogenesis.Materials and methodsA series of 135 sporadic invasive ductal carcinomas resected between 1989 and 1992 at Institut Bergonie underwent PTEN molecular genetic screening through QMPSF to detect gross genomic rearrangements and the recently developed Enhanced Mismatch Mutation Analysis (EMMA) to detect point mutations and to confirm gross genomic rearrangements. Tumours with a suspected PTEN large deletion identified using these techniques, along with any additional tumours previously shown to have decreased or absent PTEN levels and/or loss at 10q23.3, were analyzed using Agilent 4x44K high density oligo CGH arrays. The TP53 status of all tumours was assessed through IHC and direct sequencing. In addition, molecular analysis of the recurrent point mutations of PI3KCA, the catalytic subunit of the PI3 kinase, was performed.ResultsGross PTEN gene rearrangements were detected in 48 tumours through QMPSF ; 19 biallelic large deletions, 21 monoallelic large deletions and 8 large duplications. Variant EMMA profiles indicating a PTEN point mutation have been identified in approximately 15% of tumours which are confirmed by direct sequencing. High density oligo CGH array performed on 54 tumours demonstrates 7 monoallelic large deletions and 9 biallelic large deletions to date (analysis to be completed). A total of 39 tumours were shown to have mutant TP53 on IHC and/or a TP53 mutation, which interestingly only includes 8/19 tumours with a biallelic PTEN large deletion. Finally, an overall assessment of the above gene status, including results of the PI3KCA point mutation screen will be presented.ConclusionThis study shows that the predominant mechanism of PTEN inactivation in sporadic breast carcinomas is through gross genomic rearrangements rather than deleterious point mutations, and that this is not restricted to BRCA1-mutated tumours. Furthermore, previous reports have suggested that biallelic inactivation of PTEN in tumours with wild-type TP53 would result in cell death and therefore not be advantageous for tumour growth. In this series, we did not observe a correlation between biallelic inactivation of PTEN and TP53 mutation status (p=0.31, chi-squared test). Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3151.

Multiple-input multiple-output (MIMO) systems can provide two kinds of gain: diversity gain and multiplexing gain. Most existing MIMO schemes, including space-time coding and layered space-time, aim at maximizing either of them. Group transmission and detection is a good way to get a tradeoff between these two gains. In this paper, the diversity-multiplexing tradeoff functions of 3 schemes based on group transmission and detection, quasi-orthogonal group space-time (QoGST), group layered space-time (GLST) and layered space-time block codes (LSTBC), are provided and a vivid comparison among them demonstrates that QoGST achieves the best diversity-multiplexing tradeoff. GLST also gets significant gains over LSTBC. Simulation results will validate the analysis and show that QoGST can achieve at least 3 dB gain over GLST and 12 dB over LSTBC at a FER of 10/sup -3/, for instance.

MIMO systems have been shown to provide significant performance gains over traditional single antennas systems that fall in two categories: diversity and multiplexing rate. A tradeoff between these gains was recently put in evidence and has been quantified with the optimal detection. We consider the evaluation of such tradeoff when group detection is applied and particularly when the group zero forcing (GZF) receiver structure is considered. To do so, we define and evaluate the outage probability per group and derive the tradeoff obtained by each of the groups. The overall system tradeoff is then given by the minimum group tradeoff performance. Optimal rate allocation is also proposed so as to maximize GZF tradeoff performance. Comparison for a given group partition with equal rate allocation shows that optimal rate allocation allows us to both maximize the diversity and the multiplexing rate of GZF. Furthermore, considering a fixed number of antennas, we find the minimum required number of groups for a given tradeoff level, as well as the optimal group partition that maximizes the system tradeoff. Numerical results demonstrate the optimality of this scheme. Significant diversity gains are put in evidence demonstrating that GZF can efficiently bridge the gap between BLAST and the optimal receiver while offering lower levels of complexity.