Search results for " Impedance"
showing 10 items of 380 documents
Acute cytotoxicity and apoptotic effects after l-Pam exposure in different cocultures of the proximal and distal respiratory system.
2009
Abstract Sulphur and nitrogen mustard are strong alkylating agents which can cause after inhalation acute lung injury in the larynx, trachea and large bronchi and can lead to alveolar edema. In our study we tested the N-Lost l -Phenylalanine Mustard ( l -Pam). Therefore we seeded the alveolar type II cell line NCI H441 on the upper membrane of a Transwell filter plate and the endothelial cell line ISO-Has-1 on the lower side of the membrane for the alveolar model and combined the human bronchial explant-outgrowth cells and fibroblasts in the bronchial model and exposed both models with various concentrations of l -Pam. Treatment with l -Pam led to a concentration-dependent decrease of the t…
A Deep Insight into Different Acidic Additives as Doping Agents for Enhancing Proton Conductivity on Polybenzimidazole Membranes
2020
[EN] The use of phosphoric acid doped polybenzimidazole (PBI) membranes for fuel cell applications has been extensively studied in the past decades. In this article, we present a systematic study of the physicochemical properties and proton conductivity of PBI membranes doped with the commonly used phosphoric acid at different concentrations (0.1, 1, and 14 M), and with other alternative acids such as phytic acid (0.075 M) and phosphotungstic acid (HPW, 0.1 M). The use of these three acids was reflected in the formation of channels in the polymeric network as observed by cross-section SEM images. The acid doping enhanced proton conductivity of PBI membranes and, after doping, these conducti…
EIS and Ac-electrogravimetry study of PB films in KCl, NaCl, and CsCl aqueous solutions
2003
Prussian Blue films have been studied by means of ac-electrogravimetry, electrochemical impedance spectroscopy, and electrochemical quartz crystal microbalance in different aqueous salt solutions. Impedance data was interpreted in terms of a model based on a potential drop at the electrode/film interface and a potential drop at the film/solution interface. Quantitative results obtained by the fitting of impedance and ac-electrogravimetry allow to conclude that the main contribution to the potential drop at the film/solution interface is due to the dehydration-hydration process of cations on entering or leaving the film.
Innovative Combination of Three Alternating Current Relaxation Techniques: Electrical Charge, Mass, and Color Impedance Spectroscopy. Part II: Prussi…
2009
The simultaneous recording of three impedance functions (electrochemical impedance, color, and mass impedance) allows the role of different species to be distinguished easily during electrochemical processes in conducting and electrochromic films. Herein, this technique has been applied to the study of the Prussian blue films at several potentials between the blue form (Prussian blue) and the colorless form (Everitt’s salt). At these potentials, these electrochemical reactions take place by means of exchange of different ions. Thus, the exchange of potassium cations is related to the changes of absorbance at 690 nm, whereas the exchange of protons does not introduce color changes at this wa…
Electrochemical impedance spectroscopy as a tool to estimate thickness in PB films
2006
The analysis of the faradaic impedance of electroactive films provides a characteristic point from which it is possible to estimate the thickness of thin films. Thus, electrochemical impedance spectroscopy was used in this paper as a fast and easy technique to estimate this thickness. The proposed method was checked on PB films. Keywords: Prussian blue, Electrochemical impedance spectroscopy, Thickness
Correction of mass drift in ac-electrogravimetry of Prussian Yellow films. Mass impedance under apparently non-steady state condition
2014
Abstract Mass impedance spectroscopy allows the modulated response of mass of a resonant electrode to be followed at different perturbation frequencies during electrochemical impedance spectroscopy experiments (ac-electrogravimetry). However, some difficulties appear if a continuous mass change takes place foreign to the mass changes due to the ac-modulated electrochemical processes. A new strategy is proposed to solve this limitation. Both, mass and potential analog signals are recorded frequency by frequency from 100 Hz up to the lowest frequencies. Then, a numerical procedure based on a multiparametric fitting of raw data against the elapsed time allows the contribution due to the modula…
Audiological Investigation of Otitis Media in Children with Atopy
2011
Otitis media (OM) describes an inflammatory process within the middle ear space that is generally associated with accumulation of fluid and that may lead to hearing loss, learning difficulties, and delays in language development. The pathogenesis of OM is multifactorial, involving the adaptive and native immune system, eustachian tube dysfunction, viral and bacterial load, and genetic and environmental factors. The involvement of IgE-mediated allergic reactions in the pathogenesis of OM has been suggested by clinical observations of a high prevalence of OM among patients with allergies. Evidence from studies involving tympanometric measurements, audiometric measurements, and otoscopic exami…
Comparison of quantitative analysis techniques for the determination of heat seal lacquer layers on aluminum blister foils
2010
For decades a gravimetric method has been common standard for the determination of heat seal lacquers on aluminum blister foils. With the availability of appropriate techniques such as interferometric, infrared reflection absorption spectroscopic (IRRAS), beta backscatter, impedance spectroscopic and eddy current techniques respectively, more efficient determinations can be foreseen which are subject of the present communication. The different methods were compared to each other regarding parameters required for validation of analytical procedures according to the ICH guidelines Q2 (R1) such as linearity, precision, accuracy, robustness and quantitation limits. The interferometric, IRRAS an…
Constrained-Design of Passive UHF RFID Sensor Antennas
2013
Passive UHF RFID tags may be used, beside labeling, to remotely observe the physical/chemical change of the tagged object, through modulation of their impedance and gain, thus acting as sensor antennas. The design of this new class of devices can be mastered by fully understanding the relationship between communication and sensing with the purpose to balance the maximization of the dynamic range of the response with the stability of the read distance. A new kind of communication/sensing nomogram permits to display both behaviors in a unitary way and to predict their physical limits, as well as to formalize a multi-parameter general-purpose optimization methodology. The procedure is demonstr…
Pervasive body sensing: Implanted RFID tags for vascular monitoring
2010
Beside the common logistic usages of the Radio Frequency Identification (RFID) technology, one of the most innovative and promising applications is the possibility to process the backscattering signals to detect additional information about the target, such as its state and its evolution, without any specific embedded sensor or local power supply. The rationale of this idea lies in the clear dependence of the tag's input impedance and reflectivity on the physical and geometrical features of a real target. When the object where the tag is attached on undergoes some changes along with the time, the tag's electrical features also change and these variations can be remotely detected by the read…