Performance of a commercial polymerase chain reaction test for endocervical Chlamydia trachomatis infection in a university hospital population.

OBJECTIVES: To examine the accuracy of a commercial polymerase chain reaction (PCR) test (Amplicor CTR, Roche Diagnostic Systems, Branchburg NJ) for identification of endocervical chlamydial infections through both laboratory evaluation and among a diverse teaching hospital patient population. METHODS: Testing of reliable threshold inocula and reproducibility were carried out using laboratory stock organisms. Paired endocervical samples from patients with a wide range of indications were tested by PCR and an established culture procedure, and discrepant pairs were further analyzed to determine true results. RESULTS: Laboratory evaluation suggested that one copy of target DNA from a viable organism consistently yielded a positive result, and test reproducibility was very good, with an overall coefficient of variation of 15%. Compared to true results in 1,588 paired clinical samples from 1,489 women with a 10% prevalence of infection, the PCR test and culture yielded respective sensitivities of 87.4% and 78.0%, and negative predictive values of 98.6% and 97.6%. Specificity and positive predictive value for both tests were 100%. Cost per specimen was nearly identical at $18.84 and$18.88 respectively. Polymerase inhibitors and organisms lacking target DNA were not found in false-negative PCR samples. CONCLUSION: This commercial PCR test is accurate, cost-competitive, and much faster than culture for diagnosis of endocervical chlamydia infections in our population of intermediate prevalence of chlamydial infection

Charging/discharging kinetics of poly(3,4-ethylenedioxythiophene) in 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide ionic liquid under galvanostatic conditions

International audienc

Electrochemical behaviour of poly(3,4-ethylenedioxythiophene) in a room-temperature ionic liquid

The cyclic voltammetry responses and the redox switching dynamics of poly(3,4-ethylenedioxythiophene) (PEDOT) in a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (EMImTf2N), were investigated. The shape of the cyclic voltammograms showed two anodic and two cathodic peaks. These peak currents varied linearly with the scan rate indicating a thin-layer behaviour. No memory effects were observed during the cyclic voltammetry experiments in this ionic liquid. On the other hand, the redox switching dynamics of PEDOT were studied by means of potential step experiments. The analysis of chronocoulograms in term of RC-circuits indicated that the time dependence of the charge transferred during the potential step showed two time constants. These results were consistent with the postulated structure or morphology of the PEDOT film which contained two types of coexisting zones: a compact and an open structures. Keywords: Conducting polymer, Poly(3,4-ethylenedioxythiophene), Memory effect, Redox switching, Ionic liqui

Ions transfer mechanisms during the electrochemical oxidation of poly(3,4-ethylenedioxythiophene) in 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide ionic liquid

The cyclic voltammetry and the electrochemical impedance spectroscopy responses of p-doped poly(3,4-ethylenedioxythiophene) (PEDOT) electrodeposited on platinum electrode surface were studied in a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (EMITFSI). The influence of adding salt, lithium bis((trifluoromethyl)sulfonyl)amide (LiTFSI, Li(CF3SO2)2N), was studied. When PEDOT was prepared in acetonitrile, the cyclic voltammograms displayed two distinct anodic peaks indicating at least two redox reaction mechanisms. Results indicated that for one of these mechanisms 1-ethyl-3-methylimidazolium cation was the exchanged species during the oxidation, and at the same time bis((trifluoromethyl)sulfonyl)amide anion could be viewed as immobile ions trapped in the polymer film. The impedance responses were analyzed within two parallel diffusion paths that reflected the non-uniformity of the electroactive polymer film. The variation of the two time diffusion constants as a function of potential followed the same trend as the kinetic parameters determined by a potential step method. The total capacitance form electrochemical impedance spectroscopy was in agreement with that has obtained with cyclic voltammetry. Results showed also the importance of the electrodeposition conditions on the electrochemical behavior of PEDOT. Keywords: Poly(3,4-ethylenedioxythiophene), Ions transfer, Room-temperature ionic liquid, Conducting polymer, Impedanc

Réseaux interpénétrés électrocommandables pour l'actionnement et l'électrochromisme

Nous décrivons un nouveau concept de matériaux électriquement commandables constitués d'un réseau interpénétré de polymères (RIP) contenant au moins un polymère à conduction électronique et un polymère rendu conducteur ionique par ajout d'un électrolyte. Nous avons choisi d'utiliser comme polymère conducteur électronique le poly (3, 4-éthylènedioxythiophène) (PEDOT) considéré comme l'un des plus stables à l'état oxydé. Le polymère support d'électrolyte est un réseau (polymère réticulé) de poly (oxyde d'éthylène) (POE). Lorsque la quantité de PEDOT incorporée est relativement élevée (moins de 10 %), le système manifeste d'intéressantes et durables propriétés d'actionnement à l'air libre lorsqu'on le soumet à une faible tension. Par contre, pour une faible quantité de PEDOT (environ 0,5 %), le système constitue un dispositif autosupporté manifestant des propriétés électrochromes semblables à celles d'un film de PEDOT déposé sur un verre conducteur

Synthesis, polymerization and conducting properties of an ionic liquid-type anionic monomer

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Controlled polymerization of hexa-n-alkylcyclotrisiloxanes with long alkyl groups

Hexa-n-alkylcyclotrisiloxanes with side chains ranging from butyl up to decyl were polymerized anionically with cryptated lithium as the counterion. The polymerizations usually yielded polymers with low polydispersity, demonstrating the presence of a single growing species and the successful breaking up of aggregates. Formation of bimodal molecular weight distributions in the polymerization of the cyclic trimers containing heptyl up to decyl side chains can be explained by the presence of traces of siloxanediol, leading to some chains growing at both ends

Feasibility of conducting semi-interpenetrating networks based on a poly(ethylene oxide) network and poly(3,4-ethylenedioxythiophene) in actuator design

International audienc

Radical addition to 2‐isopropenyl‐5‐butoxyoxazole

The preparation and the spectroscopic analysis of a dimeric adduct (V) obtained from 2‐isopropenyl‐5‐butoxyoxazole (III) and α,α‐azobis‐isobutyronitrile (AIBN) (IV) are reported. It is noteworthy that (III) inhibits completely the homopolymerization of styrene. This is in strong opposition to the facile homopolymerization and copolymerization of 2‐isopropenyl‐4,5‐dimethyloxazole with styrene. The smooth formation of (V) is also in sharp contrast to the lack of reactivity of (III) towards cationic initiators. Copyright © 1986 John Wiley & Sons, Inc

Conducting IPN actuators: From polymer chemistry to actuator with linear actuation

International audienceAmong electroactive actuators, those based on electronic conducting polymers (ECPs) possess several advantages (low actuation voltages, large deformations, etc.) but also some drawbacks (bending movements only, delamination, etc.). In order to overcome the delamination process observed in working three-layered actuators, we have developed a new concept of actuator consisting in an interpenetrating polymer network (IPN) matrix in which 3,4-ethylenedioxythiophene (EDOT) is chemically polymerized. The typical IPN matrix results from the association of the two following cross-linked polymers: the first one, polyethylene oxide (PEO), will ensure the ionic conductivity of the system after salt incorporation while the second one, polybutadiene (PB), will allow to adjust the required mechanical properties. The chemical polymerization of EDOT within the IPN leads to the formation of a PEDOT gradient, its concentration decreasing from the outside faces towards the centre of the IPN. So, such a one-piece actuator is equivalent to a three-layered actuator. Applying a low potential (2–5 V) at a frequency from 0.1 to 15 Hz, up to 106 bending deformations in open air have been observed after incorporation of a room temperature ionic liquid. However, linear deformations are more interesting for a number of applications than simple bending motions. The description of the design of an open air working actuator with linear actuation is presented