The Role of Inflammatory Mediators in the Pathogenesis of Otitis Media and Sequelae

This review deals with the characteristics of various inflammatory mediators identified in the middle ear during otitis media and in cholesteatoma. The role of each inflammatory mediator in the pathogenesis of otitis media and cholesteatoma has been discussed. Further, the relation of each inflammatory mediator to the pathophysiology of the middle and inner ear along with its mechanisms of pathological change has been described. The mechanisms of hearing loss including sensorineural hearing loss (SNHL) as a sequela of otitis media are also discussed. The passage of inflammatory mediators through the round window membrane into the scala tympani is indicated. In an experimental animal model, an application of cytokines and lipopolysaccharide (LPS), a bacterial toxin, on the round window membrane induced sensorineural hearing loss as identified through auditory brainstem response threshold shifts. An increase in permeability of the blood-labyrinth barrier (BLB) was observed following application of these inflammatory mediators and LPS. The leakage of the blood components into the lateral wall of the cochlea through an increase in BLB permeability appears to be related to the sensorineural hearing loss by hindering K+ recycling through the lateral wall disrupting the ion homeostasis of the endolymph. Further studies on the roles of various inflammatory mediators and bacterial toxins in inducing the sensorineumral hearing loss in otitis media should be pursued

A novel LTPO AMOLED pixel circuit and driving scheme for variable refresh rate

This paper proposes a novel pixel circuit and driving scheme that adopts low-temperature polycrystalline silicon and oxide thin-film transistors (LTPO TFTs) for mobile devices using active-matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit and driving scheme provide uniform luminance and render flicker invisible at variable refresh rates (VRRs) from 1 to 120 Hz. Using the proposed pixel circuit with extended compensation time (tCOMP) improves the luminance uniformity at a high-frame rate. The proposed driving scheme applies a voltage to the driving TFTs (D-TFTs) higher than the programmed data voltage during the skip frame. This reduces the flicker caused by the hysteresis of D-TFTs during low-frame rate driving. A 6.0-inch quad high-definition (QHD) LTPO-based AMOLED display was fabricated using the new pixel circuit and driving scheme. Experimental results of the proposed pixel circuit show that the standard deviation of luminance was reduced from 0.056 to 0.008 by extending tCOMP from 2 to 8 µs. The flicker level was −51 dB, so there was no visual artifact during 1 Hz driving. A flicker-free LTPO-based AMOLED display with low power consumption is possible; driving can proceed in 1–120 Hz range

P-modified and carbon shell coated Co nanoparticles for efficient alkaline oxygen reduction catalysis

Described herein is the development of a novel Co-based oxygen electrode catalyst coupled with unique carbon structures. The present carbon shell coated Co nanoparticles of which the surface composites are modified by phosphorus incorporation, exhibit efficient oxygen reduction activities as well as oxygen evolving properties.N

Phosphate adsorption and its effect on oxygen reduction reaction for PtxCoy alloy and Aucore–Ptshell electrocatalysts

The phosphate adsorption characteristics and its effect on oxygen reduction reaction (ORR) were examined for various carbon-supported catalysts (Pt/C, Pt3Co/C, PtCo/C, and Aucore–Ptshell/C). Using cyclic voltammetry (CV) and the addition of phosphoric acid, the degree of phosphate adsorption for each catalyst was evaluated based on the intensity of the phosphate adsorption peaks (0.25–0.3 V and 0.5–0.65 V) and on the decrease in the platinum oxidation current (0.9 V). In the N2O reduction technique, the surface structures were analyzed using N2O as an electrochemical probe, which showed that as the Co content increased, (i) steps or defects were introduced by surface reconstruction, (ii) the phosphate adsorbed more strongly compared to Pt/C with a preference for the terrace sites, and (iii) the potential of zero total charge (PZTC) shifted to negative potentials. In the case of the Aucore–Ptshell/C, the phosphate adsorption was found to be weaker than other catalysts, including Pt/C catalyst. The relative ORR activity with PA addition, normalized by that with no phosphate adsorption, was significantly smaller for Co containing alloy catalysts (PtCo/C: 18.2%) and larger for Aucore–Ptshell (30.2%) compared with the Pt/C catalyst (27.8%), confirming the phosphate adsorption characteristics of each catalyst, as measured by CV and N2O reduction analysis.11Nsciescopu

Development of a galvanostatic analysis technique as an in-situ diagnostic tool for PEMFC single cells and stacks

A new galvanostatic analysis technique was developed for PEMFC single cells and stacks, while conventional potentiodynamic techniques, such as cyclic voltammetry for an electrochemical active surface area (EAS) and linear sweep voltammetry for a crossover current , cannot be directly utilized for stacks. Using a developed relationship for double-layer charging region, the and Cdl (double-layer capacitance) of a PEMFC single cell could be determined from the galvanostatic data under an atmosphere of nitrogen (cathodes) and hydrogen (anodes). Then, simply from the elapsed time in hydrogen adsorption/desorption region, EAS or roughness factors could be analyzed for a PEMFC single cell. For a 5-cell PEMFC stack, it was experimentally confirmed that the same analysis technique can be applied to analyze performance distribution in PEMFC stacks. As the characteristics of catalyst layers (EAS and Cdl) and polymer electrolyte membranes of individual cells can be analyzed without stack disassembly, the developed galvanostatic technique is expected to be utilized for the degradation study and performance monitoring of practical PEMFC stacks.11Nsciescopu

Effect of Se modification on RuSey/C electrocatalyst for oxygen reduction with phosphoric acid

Carbon-supported Se-modified-Ru catalysts (RuSey/C) were synthesized, and their phosphate adsorption characteristics were evaluated using electrochemical techniques and in-situ X-ray absorption spectroscopy (XAS). When phosphoric acid was added, the ORR activity of unmodified Ru/C decreased by 26.8% because the active sites were blocked by electrochemical adsorption, as confirmed by CV. However, for RuSey/C, the ORR activity was enhanced with phosphoric acid (RuSe1.56/C: 63.8%), which indicates that the kinetics at each site increased to compensate for the site blocking effect. The XAS results demonstrated that, for RuSey/C, phosphoric acid molecules or phosphate anions primarily interacted with Se atoms, and the oxidation state of Ru atoms decreased. Therefore, it was concluded that the enhanced ORR kinetics originated from the decreased oxygen binding energy with larger electrostatic repulsion. © 2012 Elsevier B.V. All rights reserved.1441sciescopu

Effect of Se modification on RuSey/C electrocatalyst for oxygen reduction with phosphoric acid

Carbon-supported Se-modified-Ru catalysts (RuSey/C) were synthesized, and their phosphate adsorption characteristics were evaluated using electrochemical techniques and in-situ X-ray absorption spectroscopy (XAS). When phosphoric acid was added, the ORR activity of unmodified Ru/C decreased by 26.8% because the active sites were blocked by electrochemical adsorption, as confirmed by CV. However, for RuSey/C, the ORR activity was enhanced with phosphoric acid (RuSe1.56/C: 63.8%), which indicates that the kinetics at each site increased to compensate for the site blocking effect. The XAS results demonstrated that, for RuSey/C, phosphoric acid molecules or phosphate anions primarily interacted with Se atoms, and the oxidation state of Ru atoms decreased. Therefore, it was concluded that the enhanced ORR kinetics originated from the decreased oxygen binding energy with larger electrostatic repulsion. Keywords: Se-modified-Ru catalyst, Oxygen reduction reaction, Phosphoric acid, High temperature-PEMF

Reversible Surface Segregation of Pt in a Pt₃Au/C Catalyst and Its Effect on the Oxygen Reduction Reaction

Reversible surface segregation of Pt in Pt₃Au/C catalysts was accomplished through a heat treatment under a CO or Ar atmosphere, which resulted in surface Pt segregation and reversed segregation, respectively. The Pt-segregated Pt₃Au/C exhibited a significantly improved oxygen reduction reaction (ORR) activity (227 mA/mg_metal) compared to that of commercial Pt/C (59 mA/mg_metal). For the Pt-segregated Pt₃Au/C, the increased OH-repulsive properties were validated by a CO bulk oxidation analysis and also by density functional theory (DFT) calculations. Interestingly, the DFT calculations revealed that the binding energy for Pt-segregated Pt₃Au (111) surfaces was 0.1 eV lower than that for Pt (111) surfaces, which has been previously reported to exhibit the optimum OH binding energy for the ORR. Therefore, the reversible surface segregation is expected to provide a practical way to control the surface states of Pt–Au bimetallic catalysts to enhance ORR activity. In addition, the Pt-segregated Pt₃Au/C showed excellent electrochemical stability, as evidenced by its high-performance retention (96.4%) after 10 000 potential cycles, in comparison to that of Pt/C (55.3%)