Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients

International audienceIn this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period is varying function of time, during exercise. This technique allows the estimation of the autonomic nervous system modulation (ANS) from the beat occurrences. The estimated respiratory sinus arrhythmia is then filtered in the time-frequency domain around the respiration using a time-varying filter. It is proven that the Spectrogram is a convenient time-frequency representation that allows the implementation of such filter. The recorded data comes from exercise test performed by ten heart transplant patients. The magnitude of the filtered modulation of the heart rate due to respiration is compared to the date of transplantation taking into account the volume of respiration. It reveals that the normalized magnitude of the filtered variability, is significantly increased as the age of transplantation is higher with a high correlation coefficient (R=0.74, p=0.01). This correlation raised to 0.82 when considering dynamic behavior of the parameters. Applied to our dataset, standard parameter fails to exhibit such correlation

Superconductivity in hole-doped C60 from electronic correlations

We derive a model for the highest occupied molecular orbital band of a C60 crystal which includes on-site electron-electron interactions. The form of the interactions are based on the icosahedral symmetry of the C60 molecule together with a perturbative treatment of an isolated C60 molecule. Using this model we do a mean-field calculation in two dimensions on the [100] surface of the crystal. Due to the multi-band nature we find that electron-electron interactions can have a profound effect on the density of states as a function of doping. The doping dependence of the transition temperature can then be qualitatively different from that expected from simple BCS theory based on the density of states from band structure calculations

EuPathDomains: The Divergent Domain Database for Eukaryotic Pathogens

International audienceEukaryotic pathogens (e.g. Plasmodium, Leishmania, Trypanosomes, etc.) are a major source of morbidity and mortality worldwide. In Africa, one of the most impacted continents, they cause millions of deaths and constitute an immense economic burden. While the genome sequence of several of these organisms is now available, the biological functions of more than half of their proteins are still unknown. This is a serious issue for bringing to the foreground the expected new therapeutic targets. In this context, the identification of protein domains is a key step to improve the functional annotation of the proteins. However, several domains are missed in eukaryotic pathogens because of the high phylogenetic distance of these organisms from the classical eukaryote models. We recently proposed a method, co-occurrence domain detection (CODD), that improves the sensitivity of Pfam domain detection by exploiting the tendency of domains to appear preferentially with a few other favorite domains in a protein. In this paper, we present EuPathDomains (http://www.atgc-montpellier.fr/EuPathDomains/), an extended database of protein domains belonging to ten major eukaryotic human pathogens. EuPathDomains gathers known and new domains detected by CODD, along with the associated confidence measurements and the GO annotations that can be deduced from the new domains. This database significantly extends the Pfam domain coverage of all selected genomes, by proposing new occurrences of domains as well as new domain families that have never been reported before. For example, with a false discovery rate lower than 20%, EuPathDomains increases the number of detected domains by 13% in Toxoplasma gondii genome and up to 28% in Cryptospordium parvum, and the total number of domain families by 10% in Plasmodium falciparum and up to 16% in C. parvum genome. The database can be queried by protein names, domain identifiers, Pfam or Interpro identifiers, or organisms, and should become a valuable resource to decipher the protein functions of eukaryotic pathogens

Theory for transport through a single magnetic molecule: Endohedral N@C60

We consider transport through a single N@C60 molecule, weakly coupled to metallic leads. Employing a density-matrix formalism we derive rate equations for the occupation probabilities of many-particle states of the molecule. We calculate the current-voltage characteristics and the differential conductance for N@C60 in a break junction. Our results reveal Coulomb-blockade behavior as well as a fine structure of the Coulomb-blockade peaks due to the exchange coupling of the C60 spin to the spin of the encapsulated nitrogen atom.Comment: 5 pages, 4 figures, v2: version as publishe

The Networked Smart Gadgets and Their Role(s) in Enhancing Learning Autonomy in Higher Education’s EFL Context

The present study explores the perceptions of EFL teachers in higher education on the role of handheld networked devices in promoting autonomous learning. In this project 43 male teachers from King Abdulaziz University (KAU) and the University of Jeddah (UJ) in Saudi Arabia (KSA) responded to a survey. Qualitative data, on the other hand, was gathered through a silent interview where informants answered five open-ended questions related to study’s research questions. The findings revealed the participants value the usefulness of smartphones in enhancing autonomy in language learning. They were also of the view that smartphones have beneficial characteristics when used in actual classroom. In addition, the results show that most of the participants are for a purposeful and guided integration of this type of technology in order to help learners develop the required linguistic and extra-linguistic skills. Equally important was the finding that use the of smartphones along well-developed L2 learning applications in language learning cannot replace the teachers’ vital and crucial role in the whole learning process

Important role of alkali atoms in A4C60

We show that hopping via the alkali atoms plays an important role for the t1u band of A4C60 (A=K, Rb), in strong contrast to A3C60. Thus the t1u band is broadened by more than 40 % by the presence of the alkali atoms. The difference between A4C60 and A3C60 is in particular due to the less symmetric location of the alkali atoms in A4C60.Comment: 5 pages, revtex, 2 figures, submitted to Phys. Rev. B more information at http://www.mpi-stuttgart.mpg.de/dokumente/andersen/fullerene

Encapsulation de la vitamine E dans des vecteurs pharmaceutiques inhalables préparés par des contacteurs à membrane

The present study investigated the preparation of pharmaceutical drug carriers encapsulating the vitamin E and intended for pulmonary administration after nebulisation. Vitamin E, a physiological antioxidant, could be used to prevent cigarette smoke toxicity since several pulmonary disorders are mainly caused by oxidative stress phenomena. The methods used for the drug carriers’ preparation were based on the membrane emulsification principle. In these methods, the to-be-dispersed phase was injected in the continuous phase through the pores of a microporous membrane. The advantages of this method are: a better control over the diffusive mixing at the liquid / membrane interface and thus a fine control of droplets size distribution, a less energy consumption and an easy extrapolation of the obtained results for an industrial large scale-up. In order to investigate the preparation processes, key parameters influence on particles characteristics was investigated. Different experimental set-ups were used: (i) tubular membranes with a cross flow circulation of the continuous phase, (ii) stirred cell device with a flat micro-engineered membrane, (iii) oscillating membrane module in a stationary continuous phase. For direct emulsification, various membranes were used such as : SPG membranes, micro-engineered membranes and ceramic membranes. For premix emulsification, a packed bed of glass beads, called dynamic membrane, was studied. Four different drug carriers were developed during this study: liposomes, micelles, nano-emulsion and solid-lipid particles. The different encapsulating systems were characterized in terms of size distribution, zeta potential, microscopic morphology, encapsulation efficiency and stability. Results showed that the obtained drug carriers presented convenient properties. After nebulization of vitamin E encapsulating systems, the obtained aerosols presented satisfying aerodynamic characteristics which allowed the prediction (using a mathematical model) of a high level of vitamin E deposit on its action siteL'objectif de ce travail est de développer des vecteurs pharmaceutiques, encapsulant la vitamine E, adaptés à l'administration pulmonaire par aérosolisation. La vitamine E, antioxydant physiologique, peut être utilisée pour lutter contre les phénomènes du stress oxydatif en particulier ceux observés au niveau pulmonaire. L'encapsulation de la vitamine E dans des vecteurs inhalables a été envisagée afin d'optimiser son efficacité thérapeutique en améliorant la concentration du principe actif pouvant atteindre son site d'action, les alvéoles pulmonaires. Les différents systèmes d'encapsulation de la vitamine E ont été préparés par des méthodes utilisant des contacteurs à membrane. Le principe de préparation se résume au passage de la phase dispersée, à travers les pores d'une membrane microporeuse, au sein de la phase continue. Les avantages de cette technique sont en particulier une bonne reproductibilité et un faible apport d'énergie et par conséquent un coût d'exploitation modéré. De plus, les procédés à base de contacteurs à membrane se prêtent aisément au passage à l'échelle de production industrielle. Au cours de ce travail, les paramètres influençant le procédé de fabrication par contacteur à membrane ont été étudiés ; principalement la pression transmembranaire de passage de la phase discontinue, la force de cisaillement de la phase continue et la microstructure de la membrane utilisée. Différentes configurations membranaires ont été testées telles que (i) les modules membranaires tubulaires avec écoulement tangentiel de la phase continue, (ii) les membranes planes montées dans des cellules d'agitation et (iii) les membranes dotées d'un mouvement d'oscillation à l'intérieur de la phase continue. En cas d'émulsification directe, diverses membranes ont été utilisées : des membranes SPG, des membranes microsieves et des membranes en céramique. Pour la « premix emulsification » des membranes dites dynamiques, constituées par un lit de billes en verre, ont été étudiée

Assessment of liposome disruption to quantify drug delivery in vitro

Efficient liposome disruption inside the cells is a key for success with any type of drug delivery system. The efficacy of drug delivery is currently evaluated by direct visualization of labeled liposomes internalized by cells, not addressing objectively the release and distribution of the drug. Here, we propose a novel method to easily assess liposome disruption and drug release into the cytoplasm. We propose the encapsulation of the cationic dye Hoechst 34,580 to detect an increase in blue fluorescence due to its specific binding to negatively charged DNA. For that, the dye needs to be released inside the cell and translocated to the nucleus. The present approach correlates the intensity of detected fluorescent dye with liposome disruption and consequently assesses drug delivery within the cells.Eugénia Nogueira (SFRH/BD/81269/2011), Célia F. Cruz (SFRH/BD/ 100927/2014) and Ana Loureiro (SFRH/BD/81479/2011) hold scholarships from Fundação para a Ciência e a Tecnologia (FCT). This study was funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement NMP4-LA-2009-228827 NANOFOL. This study was also supported by FEDER through POFC – COMPETE and by national funds from FCT through the project PEst-UID/ BIA/4050/2013 and the strategic funding of ID/BIO/04469/2013 unit.We thank the Immuno-haemotherapy Department of Hospital de São João (Porto, Portugal) for providing buffy coats from healthy volunteers

Conception et réalisation d'un séchoir cylindro-parabolique pour les produits agro-alimentaire de la région d’eloued

Dans le domaine de la technologie de séchage, les méthodes de séchage traditionnelles sont considérées comme moins efficaces et chronophages. La présente étude vise à développer le séchoir solaire indirect pour les produits agro-alimentaires de la région d'El-Oued (Sud-Est de l'Algérie) notamment l’arachide. Le séchoir utilise un concentrateur parabolique pour améliorer ses performances en augmentant sa température et par conséquent une diminution du temps de séchage. Le séchoir solaire réalisé, dans ce travail, a été testé sur les piments rouges durant avril 2018 et 2020. La température dans la chambre de séchage est atteinte enivrante 55 °C avec un temps de séchage de 5 h, alors que le taux de séchage soit le teneur en eau passe 47 to 9% pour l’arachide et pour piment rouge le taux d’humidité dimunue de 90% à l’équilibre durant 5 heures

La gestion des centrales hydroélectriques en série par balancement des réservoirs

RÉSUMÉ Le but de cette thèse est de développer un logiciel qui puisse gérer efficacement plusieurs réservoirs et centrales hydroélectriques sur une rivière. La règle de gestion que nous avons développée consiste à trouver un compromis entre les besoins pour la compagnie de générer des bénéfices et les risques d’inondation et de manquer de l’eau, et ceci sans connaître à l’avance les apports d’eau qui entreront dans les réservoirs dans les semaines futures. Notre approche consiste tout d’abord à agréger toutes les installations hydroélectriques de la rivière de façon à n’avoir qu’un seul réservoir à gérer. Par la suite, nous déterminons une politique de gestion du réservoir unique avec la programmation dynamique stochastique. L’étape d’après consiste à répartir la production du réservoir unique entre toutes les installations de la rivière. Cette répartition entre les installations est faite par la méthode de balancement des réservoirs qui consiste à déterminer le contenu de chaque réservoir en fonction du contenu du réservoir agrégé. Les fonctions qui déterminent le contenu de chaque réservoir en fonction du contenu du réservoir agrégé sont appelées fonctions de balancement. Les fonctions de balancement sont déterminées par une méthode de régression non paramétrique appelée régression multi variée par spline adaptative (Multivariate Adaptive Regression Splines (MARS)). La méthode MARS permet d’ajuster automatiquement des modèles polynomiaux par parties. À ma connaissance, c’est la première fois qu’on utilise cette méthode de régression pour déterminer des fonctions de balancement. Pour valider la méthode que nous avons développée, nous avons comparé les résultats de cette méthode à ceux obtenus avec la programmation dynamique stochastique pour des problèmes de deux et trois réservoirs en série. Enfin, nous avons appliqué notre approche à un problème de grande taille, et plus précisément de sept réservoirs en série.----------ABSTRACT This thesis presents our approach for determining a weekly operating policy of a hydropower system consisting of several reservoirs in series using an aggregation disaggregation method and a balancing rule. The objective function consists in maximizing the difference between the revenues of the energy surplus sold on the spot market and the cost of the energy bought to meet demand. The first step of the method consists in aggregating all installations on the river and then solving the aggregate model with stochastic dynamic programming. The feedback operating policy obtained by solving the aggregate model gives the amount of energy that should be stored at the end of each period. The second step consists of finding a rule and a relation which optimally allocates the entire storage between the reservoirs using a balancing rule. These rules were obtained by applying both, classical linear regression and the Multivariate Adaptive Regression Method (MARS) to results from a deterministic model that maximize hydropower production. Balancing reservoirs means managing the hydroelectric installations so that the total amount of potential energy stored in the system is distributed among the reservoirs of the system. This distribution must take into account the randomness of the reservoir inflows, the efficiency of the installations, and the variations of the water heads and the risk of spillage. This report will show how to determine and improve balancing rules for several reservoirs in series and will compare the results obtained for two and three reservoirs to those obtained with stochastic dynamic programming. The proposed method was also extended to a large scale system and more precisely to seven reservoirs in series