Showing papers in "Irbm in 2008"
TL;DR: The goals of this study were to classify various approaches used to detect the fall and to point out the difficulty to compare the results of these studies, as there is currently no common evaluation benchmark.
Abstract: Falls affect, each year, tens of million of elderly people throughout the world. It can have immediate lethal consequences but also causes many disabling fractures and dramatic psychological consequences which reduce the independence of the person. Falls in the elderly is thus a major public health problem. The “early” detection of fall consequently raises the interest of searchers, as most of elderly fallers cannot return to a standing position on their own following a fall. It is also an interesting scientific problem because it is an ill-defined process. The goals of this study were to classify various approaches used to detect the fall and to point out the difficulty to compare the results of these studies, as there is currently no common evaluation benchmark.
252 citations
TL;DR: In this article, three groups of the amperomettic biosensors such as unmediated, mediated and based on direct transfer of electrons have been thoroughly described, and their advantages and disadvantages were shown.
Abstract: Three groups of the amperomettic biosensors such as unmediated, mediated and based on direct transfer of electrons have been thoroughly described, and their advantages and disadvantages were shown. The amperometric biosensors are mostly utilized in commercial devices since they are studied to a greater extent and have some advantages. The modem commercial systems based on amperometric biosensors and its applications have been presented. The major field of employing biosensors is medical diagnostics where numerous commercial devices are currently functioning.
147 citations
TL;DR: This work deals with a comparative study of the PSD obtained from normal, epileptic and alcoholic EEG signals, using fast Fourier transform by Welch's method, auto regressive method by Yule–Walker and Burg's method and other methods.
Abstract: Electroencephalogram (EEG) analysis remains problematic due to limited understanding of the signal origin, which leads to the difficulty of designing evaluation methods. In spite of these shortcomings, the EEG is a valuable tool in the evaluation of some neurological disorders as well as in the evaluation of overall cerebral activity. In most studies, which use quantitative EEG analysis, the properties of measured EEG are computed by applying power spectral density (PSD) estimation for selected representative EEG samples. The sample for which the PSD is calculated is assumed to be stationary. This work deals with a comparative study of the PSD obtained from normal, epileptic and alcoholic EEG signals. The power density spectra were calculated using fast Fourier transform (FFT) by Welch's method, auto regressive (AR) method by Yule–Walker and Burg's method. The results are tabulated for these different classes of EEG signals.
122 citations
TL;DR: A new algorithm for recognition of QRS complexes in the electrocardiogram (ECG) based on support vector machine (SVM) could function reliably even under the condition of poor signal quality of the ECG signal.
Abstract: Among all electrocardiogram (ECG) components, the QRS complex is the most significant feature. This paper presents a new algorithm for recognition of QRS complexes in the electrocardiogram (ECG) based on support vector machine (SVM). Digital filtering techniques are used to remove power line interference and baseline wander in the ECG signal. SVM is used as a classifier to delineate QRS and non-QRS regions. Algorithm performance was evaluated against the standard CSE ECG database. The results indicated that the algorithm achieved 99.3% of the detection rate. The percentage of false positive and false negative was 12.4 and 0.7% respectively. It could function reliably even under the condition of poor signal quality of the ECG signal.
73 citations
TL;DR: In this article, the toxicity of the various metals tested toward immobilized phosphatase is ranged as follows: Cd2++>Co2+>Zn2+−>Ni2+•Pb2+
Abstract: Alkaline phosphatase conductometric biosensors consisting of interdigitated gold electrodes and enzyme membranes have been used for assessment of heavy-metal ions in water. These analytes act as enzyme inhibitors. Enzyme residual activity has been measured in Tris-nitrate buffer without metal preincubation in the presence of Mg2+ ions as activator. The results indicate that the toxicity of the various metals tested toward immobilized phosphatase is ranged as follows: Cd2+ > Co2+ > Zn2+ > Ni2+ > Pb2+. Detection limits were about 0.5 ppm for Cd2+, 2 ppm for both Zn2+ and Co2+, 5 ppm for Ni2+ and 40 ppm for lead ions. In addition, the responses during 10 h were stable (RSD 4%) and a drift of about 7% per day was observed. The storage stability in buffer solution at 4 °C remained stable for more than one month.
53 citations
TL;DR: Some of the new and innovative work that endeavours to take molecular imprinting away from its chromatographic, synthetic past are described and make use of this technique in new, exciting and developing fields, such as drug delivery, biotechnology, biosensors, protein/drug recognition and in the development of novel materials.
Abstract: The principle of molecular imprinting has repeatedly been proven a successful and effective means of creating sites of specific recognition within polymers. After almost three decades of development, we finally have some evidence of large molecule imprinting. In this review, the authors aim to bring the molecular imprinting community up-to-date. We describe here some of the new and innovative work that endeavours to take molecular imprinting away from its chromatographic, synthetic past and make use of this technique in new, exciting and developing fields, such as drug delivery, biotechnology, biosensors, protein/drug recognition and in the development of novel materials. The main discussion analyses a variety of different two-dimensional and three-dimensional approaches recently developed for the recognition of larger molecules or biomolecules, such as proteins, viruses and cells, and how the traditional imprinting methods have been adapted to suit the mass transfer requirements of these biological templates. We also review a relatively new technique that has emerged from the imprinting approach, which aims to develop novel materials from the imprints of biological materials.
51 citations
TL;DR: A review of the recent techniques developed for the noninvasive in situ study of the adhesion process as well as systems that allow the measurement of adhesion force strengths over biomaterials can be found in this article.
Abstract: A major turning point in the biomaterials field would be to develop tools that can offer greater insight into cell behaviour on material surfaces Obtaining this information is very important for the development of long-term implantable materials because it can aid in improving cell adhesion and proliferation properties The amalgamation of multiple disciplines has already produced many interesting techniques and approaches for the characterisation of cell adhesion processes and force adhesion strength determination on biomaterials In this review, the authors provide an overview of the recent techniques developed for the noninvasive in situ study of the adhesion process as well as systems that allow the measurement of adhesion force strengths over biomaterials Techniques based on light internal reflection, electrochemical impedance spectroscopy, and the quartz crystal microbalance (QCM) are discussed for their capabilities in investigating the cell adhesion process Conversely, techniques such as flow cells, centrifugation, and cytodetachers are presented for the adhesion force measurement An emphasis on atomic force microscopy (AFM) will demonstrate its ability to probe both the cell adhesion process and cell adhesion force, depending on the approach used A discussion is followed on the strengths and/or weaknesses of these techniques Finally, new trends and possible long-term directions for determining both adhesion process and force are highlighted
41 citations
TL;DR: In this paper, a disposable electrochemical sensor for the detection of hydrogen peroxide, using screen-printed carbon-based electrodes (SPCEs) modified with multi-wall carbon nanotubes (MWCNs) dispersed in a polyethylenimine (PEI) mixture, was presented.
Abstract: This paper deals with the development of a disposable electrochemical sensor for the detection of hydrogen peroxide, using screen-printed carbon-based electrodes (SPCEs) modified with multi-wall carbon nanotubes (MWCNs) dispersed in a polyethylenimine (PEI) mixture. The modified sensors showed an excellent electrocatalytic activity towards the analyte, respect to the high overvoltage characterising unmodified screen-printed sensors. The composition of the PEI/MWCNT dispersion was optimised in order to improve the sensitivity and reproducibility. The optimised sensor showed good reproducibility (10% RSD calculated on three experiments repeated on the same electrode), whereas a reproducibility of 15% as RSD was calculated on electrodes from different preparations. Preliminary experiments carried out using glucose oxidase (GOD) as biorecognition element gave rise to promising results indicating that these new devices may represent interesting components for biosensor construction.
36 citations
TL;DR: Results showed that GPTS monolayer, allowing covalent attachment of antibodies bioreceptors, is better suited than DTSP and protein G to obtain a dense, stable and reproducible sensitive layer of antibodies.
Abstract: A multipurpose Love acoustic wave biosensor is described in this article. As mass loading is one of the main effect involved in acoustic wave sensors, a great range of biomolecules could be detected using such sensors. In this way, the antibody/antigen binding property was used to immobilise the target species. We first compared different coupling agents to link the antibodies sensitive layer to the SiO2 sensor surface. Results showed that GPTS monolayer, allowing covalent attachment of antibodies bioreceptors, is better suited than DTSP and protein G. It permits to obtain a dense, stable and reproducible sensitive layer of antibodies. Then, different biological species with different size and shape like proteins, bacteriophages or bacteria were detected using such sensor. Different models have been chosen to validate the effective detection of a large species range: an anti-mouse antibody has been used to simulate small molecules (
24 citations
TL;DR: In this article, the rib cage was reconstructed six times and shape and morphometric comparisons were performed between the reconstructions realised by the same observer and by different observers, which demonstrated a good intra-observer reproducibility for local and global morphometric parameters.
Abstract: Objective Few authors propose in vivo tools for 3D geometrical description of the rib cage for clinical or biomechanical applications. The purpose of this study is to present a method providing a personalized 3D geometry of the rib cage from biplanar X-rays, and to evaluate its intra- and interobserver reproducibility. A morphometric study of asymptomatic rib cages is also presented. Materials and methods Both frontal and lateral radiographs were taken on 15 asymptomatic volunteers. For each set of stereoradiographs the rib cage was reconstructed six times. Then, shape and morphometric comparisons were performed between the reconstructions realised by the same observer and by different observers. Results The extensive reproducibility evaluation performed demonstrated a good intra-observer reproducibility for local and global morphometric parameters, and a good interobserver reproducibility for global parameters (twice the standard deviation [2S.D.] Discussion The present study evaluated the intra- and interobserver reproducibility of a 3D reconstruction method of the rib cage whose accuracy was previously evaluated. Reproducibility results could not be compared to previous studies because the evaluation procedures were different. However, the morphometric data provided by the present stereoradiographic method could be compared and were found globally consistent with the previous published data. Conclusion The present study completes the evaluation of a stereoradiographic 3D reconstruction method of the rib cage. In addition, the morphometric data acquired will have an important clinical significance for researchers evaluating chest cage morphometry and development.
23 citations
TL;DR: In this paper, a nonlinear analysis of EEG signals was conducted to compare the differences in the nonlinear characteristics of the EEG during normal state and the epileptic state, and to test the hypothesis whether EEG signals were in accordance with linear stochastic models.
Abstract: Objectives The electroencephalogram (EEG) signal contains information about the state and condition of the brain. The aim of the study is to conduct a nonlinear analysis of the EEG signals and to compare the differences in the nonlinear characteristics of the EEG during normal state and the epileptic state. Data The EEG data used for this study – which consisted of epileptic EEG and normal EEG – were obtained from the EEG database available with the Bonn University, Germany. Results The attractors seen in normal and epileptic human brain dynamics were studied and compared. Surrogate data analyses were conducted on two nonlinear measures, namely the largest Lyapunov exponent and the correlation dimension, to test the hypothesis whether EEG signals were in accordance with linear stochastic models. Discussions The existence of deterministic chaos in brain activity is confirmed by the existence of a chaotic attractor; also, saturation of the correlation dimension towards a definite value is the manifestation of a deterministic dynamics. Also a reduction is observed between the dimensionalities of the brain attractors from normal state to the epileptic state. The evaluation of the largest Lyapunov exponent also confirms the lowering of complexity during an episode of seizure. Conclusion In case of Lyapunov exponent of EEG data, the change due to surrogating is small suggesting that it is not representing the system complexity properly but there is a marked change in the case of correlation dimension value due to surrogating.
TL;DR: It is illustrated the importance to identify the various pitfalls inherent to molecular analysis throughout an elaboration and analysis line: choice of solid support, surface physicochemistry, immobilisation of biomolecules, biomolecular recognition, microfluidics and detection.
Abstract: The present review describes the multidisciplinary approach followed by the Chemistry and Nanobiotechnology group of INL since ten years, to develop a complete technological platform dedicated to molecular diagnosis using biochips and biosensors. This work, replaced in an international context, illustrates the importance to identify the various pitfalls inherent to molecular analysis throughout an elaboration and analysis line: choice of solid support, surface physicochemistry, immobilisation of biomolecules, biomolecular recognition, microfluidics and detection.
TL;DR: This study begins with describing the new technique, which consists in filtering respiratory surface electromyogram signals (EMG + PLI), then, becoming familiar with it, and compared the method with the previous known techniques.
Abstract: This work focuses on the power line interference (PLI) rejection from surface EMG signal. It contains three parts: the algorithm, the experimental setting and the results. This study begins with describing the new technique, which consists in filtering respiratory surface electromyogram signals (EMG + PLI), then, becoming familiar with it. The proposed algorithm requires only one channel to both estimating the adaptive filter input reference noise and the EMG signal. The algorithm of PLI rejection has been organized into two steps. The first step insists to apply adaptive filter, especially the LMS one, in which the reference input is mathematically constructed using two different cosine functions; 50 Hz (the fundamental) function and 150 Hz (the first harmonic) function. Whereas, the second step applies the matching pursuit algorithm that uses the cosine packet dictionary to improve the result of PLI obtained at the first step. After trying statistical, as well as mathematical analysis, the complete investigation ensures that all details and steps make proof that our rigorous method is appropriate, we have also compared our method with the previous known techniques.
TL;DR: In this paper, the surface properties of thrombogenesis and haemolysis were compared in these three groups to identify a suitable method of processing so that it could be used in the vascular system without any thromboembolic complication.
Abstract: Versatile use of bovine pericardium in clinical cardiovascular surgery requires processing, especially cross-linking, to make the tissue non antigenic and mechanically strong. Forty-nine bovine pericardia were made acellular and then cross-linked by two different methods, group A (20) with formalin and group B (29) with heparin and subsequently, as a final measure, five of group B pericardia were gamma-ray sterilized with stipulated dose of 25 kGy and classified as group C. The surface property of thrombogenesis and haemolysis were compared in these three groups to identify a suitable method of processing so that it could be used in the vascular system without any thromboembolic complication. Extensive microscopical examination, mechanical testing and other physical property for biocompatibility studies were conducted on these three different groups with key focus on in vitro thrombogenicity studies. Heparin treated group B bovine pericardium appeared to be the best method of processing among these three by the above studies and was confirmed by laser confocal microscopy. Heparin cross-linked and heparin sodium treated processing had gained the higher tensile strength, and appeared to be nonthrombogenic, noncalcifiable (by animal experiments), biocompatible biomaterial, which can be used clinically.
TL;DR: In this article, the grafting of red blood cells (RBC) onto a gold electrode was described, where the anti-D layer was deposited onto a protein G layer and the bridge between the protein G and the gold transducer was formed using a mixed thiol-based self-assembled monolayer (SAM) (a mixture of 11-mercaptoundecanoic acid and 6mercapto-1hexanol in a 1/10 ratio).
Abstract: This study describes the grafting of red blood cells (RBC) onto a gold electrode. The erythrocytes were immobilised using antigen/antibody crosslinking based on the bonding of anti-D with the corresponding antigen of the RBC membrane that is shared by all erythrocytes from the positive rhesus group (O + ). To optimise the reproducibility of the modified electrode and to avoid nonspecific interactions, the anti-D layer was deposited onto a protein G layer. The bridge between the protein G and the gold transducer was formed using mixed thiol-based self-assembled monolayer (SAM) (a mixture of 11-mercaptoundecanoic acid and 6-mercapto-1-hexanol in a 1/10 ratio). Each layer deposited was characterized, firstly, with a quartz crystal microbalance to obtain the deposited mass and the corresponding number of moles per square centimetres and secondly, by electrochemical impedance spectroscopy (EIS) using a redox couple Fe(CN) 6 3−/4− (1:1) as an EIS probe. Subsequent modelling with appropriate circuitry enabled the values for each component representing the interface (electrode/film/solution) to be calculated at each step of the grafting process. From these results the surface coverage has been calculated to range from 95 to 98%.
TL;DR: In this paper, the effect of the number of polyelectrolyte layers and polarity of the outermost layer on the impedance and capacitance-voltage curves of a field-effect-based electrolyte-insulator-semiconductor (EIS) sensor was investigated.
Abstract: Impedance-spectroscopy (IS) and capacitance–voltage characteristics of a field-effect-based electrolyte–insulator–semiconductor (EIS) sensor functionalised with polyelectrolyte (PE) multilayers have been investigated. The PE multilayers were obtained using the layer-by-layer technique by a consecutive adsorption of positively charged (poly(allylamine hydrochloride)) (PAH) and negatively charged (poly(sodium 4-styrene sulfonate)) (PSS) on a p-Si–SiO2 structure. Alternating shifts in the impedance and capacitance–voltage curves have been observed after the adsorption of each polyanion and polycation layer, respectively. The effects of the number of the adsorbed PE layers and polarity of the outermost layer on the impedance and capacitance–voltage curves are discussed.
TL;DR: In this paper, le titane is used in the chirurgie orthopedique et dentaire for its excellent resistance a la corrosion and sa biocompatibilite.
Abstract: Resume Le titane est utilise dans le domaine de la chirurgie orthopedique et dentaire pour son excellente resistance a la corrosion et sa biocompatibilite. Afin d’ameliorer l’osteointegration a long terme du titane, des polymeres bioactifs porteurs de groupements ioniques tels que sulfonate (polystyrene sulfonate de sodium, polyNaSS) sont greffes de maniere covalente a leur surface par modification chimique et polymerisation radicalaire. La caracterisation des surfaces greffees realisee par spectroscopie infrarouge transformee de Fourier et spectroscopie de photoelectrons X, confirme la presence des groupements sulfonate a la surface des echantillons. La quantification de ces groupements, realisee par dosage colorimetrique, a ete evaluee a 5 μg/cm 2 . Par ailleurs, une etude de culture cellulaire in vitro a ete realisee afin d’etudier l’influence de ces polymeres bioactifs sur la mineralisation de cellules osseuses humaines (MG63). Au bout de 28 jours de culture sur les differentes surfaces greffees avec du polyNaSS et non greffees, la quantite de calcium presente sur chacune des surfaces est quantifiee. Les resultats obtenus montrent que la mineralisation de ces cellules est amelioree en presence du polyNaSS avec une quantite de calcium plus grande que dans le cas des surfaces non greffes. Parallelement a l’etude de culture cellulaire, l’adhesion des cellules sur le titane a ete evaluee en soumettant ces cellules ensemencees sur les surfaces a une force de cisaillement. Les resultats ont montre que les forces d’interaction des cellules sont plus importantes dans le cas des surfaces greffees avec du polyNaSS. Une etude est actuellement realisee en presence d’autres groupements ioniques tels que carboxylate et phosphate, afin d’etudier la reponse cellulaire.
TL;DR: A novel strategy for the design of a clinical urea biosensor using a process based on assembled multilayer systems and it was shown that capacitive measurements can be used to quantify the interaction between molecular systems, based on avidin and biotin molecules.
Abstract: In this report, we describe a novel strategy for the design of a clinical urea biosensor using a process based on assembled multilayer systems. Biotinylated enzyme (urease–subiotin) was immobilized on the biotinylated polypyrrole coated Chemical field effect capacitance (ChemFEC) devices using the high avidin–biotin affinity. The immobilized enzyme activity was checked by its catalytic conversion of urea into carbon dioxide and ammonia. Electrochemical response of the bridge system constructed on Si/SiO 2 /Si 3 N 4 electrodes to urea addition was evaluated using the capacity–potential measurements. In addition, contact-angle measurements were carried out to control the change of surface energy and their components before and after each layer formation. The developed urea biosensor demonstrates high performances: a good sensitivity of 50 mV/pUrea in the linear urea concentration range from 10 −4 to 10 −1 M and an excellent operational stability after three weeks of continuous use. The immobilized urease was characterised through its apparent Michaelis–Menten constant (5 mM) and the activation energy of the enzymatic reaction (20 kJ mol −1 ). It was also shown that capacitive measurements can be used to quantify the interaction between molecular systems, based on avidin and biotin molecules.
TL;DR: In this article, the global antioxidant capacity was deduced from the anodic charge passed during the plotting of cyclic voltammograms on platinum or gold microelectrodes on skin surface without any gel or water added.
Abstract: Potentiometry and cyclic voltammetry were proposed as simple, reliable and non invasive methods for the simultaneous determination of pH and antioxidant properties of skin. Experiments were performed with microelectrodes just deposited on skin surface without any gel or water added. pH was measured by means of the zero current potential of a tungsten W/WO3 sensor. A nerstian response was recorded in pH range 4 to 6 corresponding to the normal skin pH values. The global antioxidant capacity was deduced from the anodic charge passed during the plotting of cyclic voltammograms on platinum or gold microelectrodes. Comparing the half wave or peak potentials of these curves with those recorded for experiments performed in aqueous solution, the main hydrophilic antioxidants species were detected, i.e. ascorbic acid, uric acid and glutathione. This relatively easy-to-use analytical method made it possible to follow in real time the efficiency of topic treatment as well as to study the influence of oxidative stress.
TL;DR: In this article, the authors show that the efficiency of separation of sources is profondement dependant on the pretraitements appliques aux donnees, i.e., the applicability of these methods for compensing ces effets perturbateurs and rendre les spectres Raman descriptibles par un modele generatif lineaire.
Abstract: Resume La spectroscopie Raman est une technique efficace d’analyse de la composition moleculaire d’echantillons biologiques. Des methodes de separation de sources peuvent etre utilisees pour separer efficacement les informations denses melangees dans les spectres Raman acquis. Des deformations telles que le fond de fluorescence, le desalignement des pics ou l’heterogeneite de la largeur des pics remettent en cause le modele generatif lineaire requis par les methodes de separation de sources. Des pretraitements sont necessaires pour compenser ces effets perturbateurs et ainsi rendre les spectres Raman descriptibles par un modele generatif lineaire. Nous montrons dans cet article que l’efficacite des methodes de separation de sources est profondement dependante des pretraitements appliques aux donnees. L’etude du deparaffinage numerique du signal Raman d’une biopsie de peau humaine prouve les ameliorations ainsi apportees. Les methodes de separation de sources appliquees dans cet article sont : un algorithme classique d’analyse en composantes independantes (ACI), nomme joint approximate diagonalization of eigenmatrices (JADE) et deux methodes de separation de sources positives, appelees la factorisation en matrices non-negatives (FMN) et la separation de sources positives par maximum de vraisemblance (SSPMV).
TL;DR: Focussed ultrasound system developed for deep-seated tumours, say in the complex brain tissue, is studied here and nanotechnological approach is presented for different control mechanisms for the control of ultrasound intensity, focussing beam, thermal profile of temperature distribution in the tissue and dosage control levels.
Abstract: Hyperthermia is a technique of raising the temperature locally to treat say tumours. There are several hyperthermia modalities like radio frequency (RF), microwave, and ultrasound. RF and microwave hyperthermia are good for superficial treatment while ultrasound is good for the therapeutic treatment of deep-seated tumours, with the ability of easy focussing. Focussed ultrasound system developed for deep-seated tumours, say in the complex brain tissue, is studied here. Nanotechnological approach is presented here for different control mechanisms for the control of ultrasound intensity, focussing beam, thermal profile of temperature distribution in the tissue and dosage control levels. Ex vivo study of excised tumours, like breast tumours, bone tumours and other such samples, with the present system is also presented. Physical and biological effects on the human health are discussed.
TL;DR: Rat MRI using an 0.1 T device allows to answer to the biological questions studied in this work at the expense of long acquisition times compared to high field MRI.
Abstract: Objective This work aims at demonstrating the interest of low field magnetic resonance imaging (MRI) for in vivo imaging in rat. Material and methods MRI is performed using an open resistive 0.1 T magnet with a homogeneous zone measuring 6 cm × 10 cm × 10 cm. Rats under isoflurane gaseous anesthesia are placed in a technical cell for small animal imaging. Radio frequency solenoidal coils are developed for each application. Gradient echo T1 and T2-weighted sequences are programmed to acquire 3D data in vivo in rats. Results Acquisition times are comprised between 1 min for scout sequences and 2 h 10 min to acquire volumes with in-plane pixel size ranging from 0.37 to 1 mm and a slice thickness between 0.37 mm and 1.88 mm. Information obtained from our acquisitions are comparable to those reported in the literature about five applications: 1: intracerebral glioma; 2: cerebral contrast enhancement using manganese; 3: description of knee joint anatomy; 4: cardiac dynamic acquisition synchronized on cardiac rhythm; 5: whole body (thorax and abdomen) acquisition. Conclusion Rat MRI using an 0.1 T device allows to answer to the biological questions studied in this work at the expense of long acquisition times compared to high field MRI. Low field MRI offers economical and technical characteristics that could make it attractive to a non-specialized scientific community aiming at realizing daily MRI in vivo in rat.
TL;DR: The circulatory response to standing is discussed in five cosmonauts before and after short-duration spaceflight, and failing adaptive mechanisms of orthostatic blood-pressure control in patients who are prone to head-up tilt induced syncope are discussed.
Abstract: A total of five studies have been included in this work. The first two studies describe cardiovascular response changes to (simulated) microgravity in healthy subjects. In a third study, the circulatory response to standing is discussed in five cosmonauts before and after short-duration spaceflight. The last two studies deal with failing adaptive mechanisms of orthostatic blood-pressure control in patients who are prone to head-up tilt induced syncope. The team of Professor A. E. Aubert (F. Beckers, K. Couckuyt and J. Liu) from the Laboratory of Experimental Cardiology of the University Hospital in Leuven was involved in the completion of this thesis. Part of the work has been coordinated by Dr. W. Wieling (J. Gisolf and J.M. Karemaker) of the Academic Medical Center in Amsterdam and by Professor H. Ector (T. Reybrouck) of the Division of Clinical Cardiology in Leuven.
TL;DR: In this article, a hexavalent chromium-selective sensor based on polymeric membranes containing trioctylphosphine oxide (TOPO) deposited on a Si/SiO 2 /Si 3 N 4 structure was developed.
Abstract: A hexavalent chromium-selective sensor, based on polymeric membranes containing trioctylphosphine oxide (TOPO) deposited on a Si/SiO 2 /Si 3 N 4 structure, has been developed. The ion-sensitivity of TOPO was investigated by capacitance measurements (C-V) and electrochemical impedance spectroscopy. A quasi-nernstian response for Cr 2 O 7 2− exchange is shown. Selectivity coefficients and detection limits of Cr(VI) in the presence of interfering anions were determined experimentally using the fixed interference method. A detection limit of 10 −5 M of Cr(VI) is obtained even in presence of sulphate and chloride ions.
TL;DR: Fluoroquinolones are antibacterial agents, effective against Gram positive and Gram negative bacteria, and their electropolymerization properties were investigated in organic media.
Abstract: Fluoroquinolones are antibacterial agents, effective against Gram positive and Gram negative bacteria. With the aim of detecting fluoroquinolones rapidly and easily, fluoroquinolone models of ciprofloxacin functionalized by pyrrole or amino groups were synthesized. The electrochemical behavior of the pyrrole derivatives and their electropolymerization properties were investigated in organic media. In parallel, the amino derivative was chemically grafted onto an electropolymerized polypyrrole film. The resulting polymer has been incubated with anticiprofloxacin antibody, leading to the antibody immobilization by an immunoreaction with the ciprofloxacin model. The impedance behavior of the modified electrode was then examined towards the effect of ciprofloxacin.
TL;DR: La publication du genome du nematode Caenorhabditis elegans en 1998 a marque un tournant dans l’ensemble des programmes de sequencage puisque, pour the premiere fois, le genome d’un organisme metazoaire etait decrypte.
Abstract: Resume La publication du genome du nematode Caenorhabditis elegans en 1998 a marque un tournant dans l’ensemble des programmes de sequencage puisque, pour la premiere fois, le genome d’un organisme metazoaire etait decrypte. Depuis cet inventaire moleculaire, il est rapidement apparu que pres de 67 % des genes associes a des pathologies chez l’homme avait un equivalent chez ce petit ver de 1 mm de long. C. elegans peut etre maintenu au laboratoire de plusieurs facons (milieux de cultures, alimentation, etc.) qu’il est possible de combiner avec des traitements par des molecules exogenes ou metabolites secondaires tout en tirant avantage du grand nombre de mutants genetiques deja disponibles ou encore des ciblages moleculaires par ARN interference ou transgenese. Grâce a ces caracteristiques, plusieurs strategies ont d’ores et deja ete developpees afin de generer des cribles de medicaments orientes vers de nouvelles cibles ou groupes de cibles therapeutiques interessantes pour la sante humaine ou encore pour decrypter certains programmes a l’origine de mecanismes physiologiques regulateurs complexes. Nous proposons ici, par l’utilisation d’exemples, d’illustrer comment de nouvelles cibles therapeutiques peuvent etres identifiees grâce a l’utilisation combinee des informations deja disponibles sur ce modele qui contribue encore a l’emergence de nouveaux concepts de genomique quantitative.
TL;DR: PIM as mentioned in this paper is a portail d'information bilingue (francais/anglais) sur le medicament, dans un contexte multiterminologique.
Abstract: Resume Objectifs L’objectif de ce travail est la creation d’un portail d’information bilingue (francais/anglais) sur le medicament, dans un contexte multiterminologique. Materiel et methodes La construction du portail d’information sur le medicament (PIM) s’est appuyee sur le portail CISMeF en adaptant certaines fonctionnalites specifiques : creation du concept de substance, regroupant des descripteurs MeSH et des supplementary concept s traitant du medicament. Nous avons cree egalement une arborescence specifique de type de ressources, pour traiter du contenant de l’information (par exemple : notice medicamenteuse). Enfin, nous avons cree un metaterme specifique « medicament » englobant semantiquement tous les concepts precedents. Resultats PIM est le resultat d’une collaboration entre l’equipe CISMeF et la societe privee Vidal, specialiste de l’information sur les medicaments. L’URL de ce site est : http://doccismef.chu-rouen.fr/servlets/PIM . Les terminologies et classifications interrogeables par le PIM sont : le MeSH, l’ATC, les codes CAS et codes EINCS, les codes francais CIS, CIP et UCD, ainsi que les noms commerciaux et les denominations communes internationales des medicaments. Discussion En 2008, la National Library of Medicine (NLM) a mis en place le « Drug Information Portal ». Ce portail permet d’acceder aux informations concernant plus de 12 000 medicaments. La recherche peut s’y effectuer a partir du nom generique ou du nom commercial. A notre connaissance, la recherche par code CAS ou ATC n’est pas possible dans le US Drug Information Portal. Conclusion La realisation du PIM permet de faciliter la recherche d’information de l’utilisateur en se restreignant au domaine medicamenteux, mais en utilisant un contexte multiterminologique.
TL;DR: In this paper, a mise en place d'un protocole experimental rigoureux, puis de methodes cinematique et dynamique inverse avancees, prenant notamment en compte les centres et axes fonctionnels et les caracteristiques inertielles personnalisees au sujet.
Abstract: Resume Compte tenu du nombre croissant de pathologies du systeme osteoarticulaire, de plus en plus d’etudes cliniques s’appuient desormais sur l’evaluation des moments articulaires en trois dimensions. Le calcul de ces moments articulaires passe par la mise en place d’un protocole experimental rigoureux, puis de methodes cinematique et dynamique inverse avancees, prenant notamment en compte les centres et axes fonctionnels et les caracteristiques inertielles personnalisees au sujet. De plus, a partir de la mesure des bras de levier musculaires et de la mise en œuvre d’une technique d’optimisation numerique, il est possible d’affiner encore l’analyse pour estimer les efforts musculaires et les actions de contact articulaire.
TL;DR: A novel visualization technique is presented to display each ECG beat, which can be used to identify different types of abnormalities in the investigation of heart disease.
Abstract: An electrocardiogram (ECG) is an electrical recording of the heart and is used in the investigation of heart disease. It displays an apparent periodicity (of about 60–100 bpm in a healthy adult), but is not exactly periodic. The symptoms of disease may show up only during certain periods of the day, and that too may occur at random in the time scale. Visual media is a most effective tool for communication, especially when the data has subtle variations. A novel visualization technique is presented to display each ECG beat. The features like PR interval, QRS width, ST interval, are extracted from the magnitude and phase plot of different lead combinations. These features are displayed on a Cartesian quadrant as different curves, with a menu driven display strategy to visualize the ECG for a chosen interval. The scheme employed can be used to identify different types of abnormalities.
TL;DR: Un outil de recherche base sur les arbres de decision, qui sont bien adaptes pour traiter de l’information heterogene and incomplete, israe sur une base de retinopathies diabetiques classifiees.
Abstract: Resume Nous proposons dans cet article un systeme de raisonnement a base de cas pour la recherche de dossiers patients similaires a un cas donne en requete. Nous nous interessons a des dossiers patients constitues de plusieurs images accompagnees d’informations contextuelles (telles que l’âge, le sexe et les antecedents medicaux du patient). Plusieurs sources d’informations (parfois incompletes) sont en effet generalement necessaires pour diagnostiquer une pathologie. Nous proposons un outil de recherche base sur les arbres de decision, qui sont bien adaptes pour traiter de l’information heterogene et incomplete. Pour prendre en compte des images dans ce systeme, nous leur associons une signature definie a partir de leur contenu numerique. La methode est evaluee sur une base de retinopathies diabetiques classifiees. Sur cette base de donnees, les resultats sont interessants : la precision atteint 79,5 % pour une fenetre de retrouvaille de cinq cas, doublant pratiquement les resultats obtenus en n’utilisant que le contenu numerique d’une image.