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Comparison of Central Corneal Thickness using Anterior Segment Optical Coherence Tomography Versus Ultrasound Pachymetry
摘要： Introduction: Corneal thickness is an important and sensitive indicator of corneal health. It is useful in monitoring corneal diseases such as corneal oedema and keratoconus, and selecting patients for refractive surgery. Central Corneal Thickness (CCT) is a risk factor for Primary Open-Angle Glaucoma (POAG). Aim: To compare CCT using ultrasound pachymetry and Anterior Segment Optical Coherence Tomography (AS-OCT), and also to find out the reproducibility of AS–OCT readings for both central and pericentral corneal areas. Materials and Methods: This prospective cross-sectional study was conducted on 120 patients above 40 years of age, and with clinically normal corneas, who underwent CCT measurements by both ultrasound and AS-OCT. Both the eyes were analysed. Two measurements by AS-OCT and 25 measurements by ultrasound pachymetry were taken. The readings were averaged and compared by paired t-test. Repeatability of the OCT pachymetry map sector averages, was assessed by pooled standard deviation, obtained from the two measurements taken from each eye. Results: The CCT in right eye by OCT and ultrasound was 516.28±29.76 μm and 532.42±29.71 μm, respectively. The CCT in left eye by OCT and ultrasound was 515.82±29.88 μm and 532.36±29.83 μm, respectively. The difference in CCT measurement by AS-OCT and ultrasound was statistically significant (p<0.001); mean ultrasound CCT being 16.14 μm and 16.54 μm greater than the mean AS-OCT, CCT in right eye and left eye respectively. For AS-OCT, intra-session repeatability was measured. Repeatability of the OCT mapping was 0.01 μm to 1.6 μm and 0.01 μm to 1.9 μm in the right eye and left eye respectively. Conclusion: The CCT measurement by ultrasound pachymetry gives higher values compared to AS-OCT measurement. Hence, they cannot be interchangeably used in clinical practice. The AS- OCT provides highly repeatable pachymetry map measurements both centrally and pericentrally.
关键词： Primary open-angle glaucoma,Reproducibility,2-mm pachymetry map
更新于2025-09-09 09:28:46
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NOVEL MATRIX SUBLIMATION DEVICE FOR MALDI MASS SPECTROMETRY IMAGING
摘要： Sublimation is a widely used method for matrix deposition in imaging mass spectrometry experiments. Still, most of the time standard glass sublimators are used for this purpose, which do not enable optimal matrix deposition reproducibility, compromising inter-experiment comparison of the results. Here we present an in-house designed stainless steel sublimator in which the parameters that have the strongest influence over matrix deposition reproducibility can be easily monitored. Using sections of human colon biopsies we demonstrate the capabilities of this new prototype.
关键词： mass spectrometry imaging,matrix sublimation,stainless steel sublimator,reproducibility,MALDI
更新于2025-09-09 09:28:46
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Repeatability and Reproducibility of Quantification of Superficial Peri-papillary Capillaries by four Different Optical Coherence Tomography Angiography Devices
摘要： This study was performed to test the repeatability and reproducibility of measurements of peri-papillary capillaries from four optical coherence tomography angiography (OCTA) devices. 109 healthy eyes were imaged with four OCTA devices (Spectralis, Optovue, Triton and Cirrus). A 3 × 3 mm scan pattern centered on the disc was repeated twice by each device. En face images of superficial capillary plexus were screened and processed for calculation. Vessel length density (VLD) was calculated on four equally divided parts of a ring between two concentric circles manually centered on the disc. General linear model (GLM) was used to test the impact of device and location on VLD. Intraclass correlation coefficient (ICC) of VLD between repeated scans was calculated. Of 218 acquisitions, 36%, 92%, 76% and 88% were eligible for analysis from Spectralis, Optovue, Triton and Cirrus, respectively. ICC was 0.94, 0.90, 0.84 and 0.87 for the four devices. GLM showed measurements significantly varied among devices (P < 0.001) and locations (P < 0.001). Pairwise comparison showed Triton = Spectralis >Optovue >Cirrus, and temporal = nasal >superior = inferior in measuring capillary VLD. This study revealed the repeatability of measuring peri-papillary capillaries was high for all four devices, while the reproducibility among the machines was unfavorable.
关键词： optical coherence tomography angiography,vessel length density,peri-papillary capillaries,reproducibility,repeatability
更新于2025-09-09 09:28:46
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[IEEE 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Erlagol (Altai Republic), Russia (2018.6.29-2018.7.3)] 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Analysis of the Technological Parameters Influence on the Reproducibility of the Active Dielectrics Properties
摘要： An analytical description of the process parameters and various industry sorts of external factors influence (heat, electrical, magnetic, mechanical) on active dielectrics properties (relative permittivity, polarization) that govern the materials use in functional electronics elements is presented. The article proves expediency of x-rays use to improve the reproducibility of dielectric properties of hydrogen-containing ferroelectrics (for example, triglycine sulfate). Higher reproducibility of parameters is due to the presence of flat areas in dependence of the relative permittivity on the electric field (cid:304)(E) during (cid:534)-radiation exposure, and therefore the additional errors of dialectic properties measurement are reduced significantly due to the impossibility of fixing the exact values of process parameters. For example, when the radiation dose D = 50 kR extra measurement error (cid:304) is reduced not less than 2.5 times.
关键词： properties reproducibility,radiation,Active dielectric,dielectric permeability,electric field strength
更新于2025-09-09 09:28:46
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Cs Oleate Precursor Preparation for Lead Halide Perovskite Nanocrystal Synthesis: The Influence of Excess Oleic Acid on Achieving Solubility, Conversion, and Reproducibility.
摘要： In the colloidal synthesis of inorganic perovskite materials, cesium oleate (CsOL) is the most commonly used Cs precursor. Yet despite its ubiquitous use in literature, CsOL has been observed to be insoluble at room temperature and leads to surprisingly inconsistent results in CsPbX3 nanocrystal synthesis depending on the Cs salt from which the precursor is derived. We show that under the conditions used in most reports, the amount of oleic acid (OA) added, while stoichiometrically sufficient, still leads to incomplete conversion of the Cs salts to CsOL. This results in a mixture of Cs sources being present during the reaction, causing decreased homogeneity and reproducibility. When a 1:5 Cs:OA ratio is used, complete conversion is readily obtained even under mild conditions, resulting in a precursor solution that is soluble at room temperature and yields identical synthetic results regardless of the initial Cs source. Further, 1H nuclear magnetic resonance (NMR) of solutions prepared using varying Cs:OA ratios shows that the maximum ratio of Cs:OA obtainable in solution is 1:5, with any excess Cs present in the precipitate. We believe the use of a soluble, fully converted CsOL reagent will improve reproducibility for Cs-based perovskite synthesis and directly benefit synthetic methods based on microfluidics.
关键词： reproducibility,inorganic perovskite materials,microfluidics,CsPbX3 nanocrystal synthesis,colloidal synthesis,oleic acid,solubility,cesium oleate
更新于2025-09-04 15:30:14