Edge Enhancement Optimization in Flexible Endoscopic Images to the Perception of Ear, Nose and Throat Professionals

Objectives: Digital endoscopes are connected to a video processor that applies various operations to process the image. One of those operations is edge enhancement that sharpens the image. The purpose of this study was to (1) quantify the level of edge enhancement, (2) measure the effect on sharpness and image noise, and (3) study the influence of edge enhancement on image quality perceived by ENT professionals. Methods: Three digital flexible endoscopic systems were included. The level of edge enhancement and the influence on sharpness and noise were measured in vitro, while systematically varying the levels of edge enhancement. In vivo images were captured at identical levels of one healthy larynx. Each series of in vivo images was presented to 39 ENT professionals according to a forced pairwise comparison test, to select the image with the best image quality for diagnostic purposes. The numbers of votes were converted to a psychometric scale of just noticeable differences (JND) according to the Thurstone V model. Results: The maximum level of edge enhancement varied per endoscopic system and ranged from 0.8 to 1.2. Edge enhancement increased sharpness and noise. Images with edge enhancement were unanimously preferred to images without edge enhancement. The quality difference with respect to zero edge enhancement reaches an optimum at levels between 0.7 and 0.9.Conclusion: Edge enhancement has a major impact on sharpness, noise, and the resulting perceived image quality. We conclude that ENT professionals benefit from this video processing and should verify if their equipment is optimally configured. Level of Evidence: N/A Laryngoscope, 2023.</p

Solid-state reference electrodes based on carbon nanotubes and polyacrylate membranes

A novel potentiometric solid-state reference electrode containing single-walled carbon nanotubes as the transducer layer between a polyacrylate membrane and the conductor is reported here. Single-walled carbon nanotubes act as an efficient transducer of the constant potentiometric signal originating from the reference membrane containing the Ag/AgCl/Cl− ions system, and they are needed to obtain a stable reference potentiometric signal. Furthermore, we have taken advantage of the light insensitivity of single-walled carbon nanotubes to improve the analytical performance characteristics of previously reported solid-state reference electrodes. Four different polyacrylate polymers have been selected in order to identify the most efficient reservoir for the Ag/AgCl system. Finally, two different arrangements have been assessed: (1) a solid-state reference electrode using photo-polymerised n-butyl acrylate polymer and (2) a thermo-polymerised methyl methacrylate:n-butyl acrylate (1:10) polymer. The sensitivity to various salts, pH and light, as well as time of response and stability, has been tested: the best results were obtained using single-walled carbon nanotubes and photo-polymerised n-butyl acrylate polymer. Water transport plays an important role in the potentiometric performance of acrylate membranes, so a new screening test method has been developed to qualitatively assess the difference in water percolation between the polyacrylic membranes studied. The results presented here open the way for the true miniaturisation of potentiometric systems using the excellent properties of single-walled carbon nanotubes

Bilateral multifocal Warthin's tumors in upper neck lymph nodes. report of a case and brief review of the literature

Cystadenolymphomas (Warthin's tumors) are the second most frequent lesions of the parotid gland. Due to their benign clinical behavior, the low rates of recurrence and malignant transformation they were classified as tumor-like lesions. In addition, a polyclonal growth of the epithelial components of the tumor could be detected. Warthin's tumors occur bilateral in 7-10%, whereas a multifocal appearance is extremely rare. Even if the pathogenesis is still unclear a heterotopia of salivary tissue during embryogenesis is the most likely explanation for the origin of these tumors in the upper neck and periparotideal region. Here we present a rare case of bilateral, multifocal, extraglandular Warthin's tumors in lymph nodes of the upper neck and give a brief review of the literature. If a primary malignancy can be excluded by a careful staging procedure prior to the operation an isolated excision of the lesions of the neck is the adequate treatment

Electronic properties, mechanical stability and reduction reaction energies for cubic lanthanide oxide composites: A computational modelling approach

Lanthanide(Ln) oxides represent an array of materials which exhibit unique properties, such as, superior mechanical, thermal, optical and magnetic properties, derived by their unfilled semicore 4f orbitals. Two forms of cerium oxide(CeO2 and Ce2O3) for instance have been the subject of numerous studies aiming to elucidate chemical and physical characteristics of their bulk and thin film properties. Cerium oxides have been widely deployed as catalysts in the preparation of active metal nanoparticles, as electrolytes or anode support materials. On the theoretical side, density functional theory(DFT) investigation has elucidated structures and electronic properties by utilizing hybrid DFT methods. Studied compounds include the A-type hexagonal structure and CeO2 with the cubic fluorite structure (space group Fm-3m). This study presents a comprehensive DFT + U account into electronic structures, mechanical properties of C-type lanthanide sesquioxides and thermodynamic (redox) properties. The aim of this work is fourfold: (1) to evaluate the effects of the Hubbard U parameter on the electronic and structural properties of C-type lanthanide sesquioxides (Ln2O3), (2) to assess the mechanical stability of all C-type lanthanide sesquioxides, (3) to elucidate the thermodynamic feasibility of CeO2 to undergo a redox reaction at temperatures relevant to catalytic applications, and (4) to underpin the effect of adding Hf and Zr to CeOδ [ δ=2-1.5] on reduction energies. We find that a Ueff value of ~ 5 eV reproduces the analogous experimental band gap of Ce2O3. Bader’s charge distributions on the C-type Ln2O3 have verified the ionic bonding nature of these compounds. Our analysis for the reduction energy of CeO2, in a wide range of temperatures, demonstrates that transfer cerium oxide between the two + 4 and + 3 oxidation states exhibit a temperature independent behavior. Preliminary results indicate that CeO2 alloyed with Hf or Zr results in enhancing its redox characteristics by lowering reduction enthalpies

Thermo-mechanical properties of cubic lanthanide oxides

This contribution investigates the effect of the addition of the Hubbard U parameter on the electronic structural and mechanical properties of cubic (C-type) lanthanide sesquioxides (Ln2O3). Calculated Bader's charges confirm the ionic character of LnO bonds in the C-type Ln2O3. Estimated structural parameters (i.e., lattice constants) coincide with analogous experimental values. The calculated band gaps energies at the Ueff of 5 eV for these compounds exhibit a non-metallic character and Ueff of 6.5 eV reproduces the analogous experimental band gap of cerium sesquioxide Ce2O3. We have thoroughly investigated the effect of the O/Ce ratios and the effect of hafnium (Hf) and zirconium (Zr) dopants on the reduction energies of CeOx configurations. Our analysis for the reduction energy of CeO2, over a wide range of temperatures displays that, shuffling between the two +4 and +3 oxidation states of Ce exhibit a temperature-independent behaviour. Higher O/Ce ratios necessitate lower reduction energies. Our results on CeHfZrO alloys are in reasonable agreements with analogous fitted values pertinent to lowering reduction energies and shrinkage in lattice parameters when contrasted with pure CeO2. Structural analysis reveals that Hf and Zr atoms in the solid solution are shifted towards the nearest vacancies upon reduction. It is hoped that values provided herein to shed an atomic-base insight into the reduction/oxidation thermodynamics of increasingly deployed catalysts for environmental applications