Purpose: To investigate the effectiveness of orthokeratology (ortho-k) lenses and corneal changes with increased compression factor for myopia control over a 2-year period.
Methods: Young participants (age: 6-<12 years), with low myopia (0.50-4.00 D) and low astigmatism (≤1.25 D), were recruited and allowed to choose to wear either single-vision spectacles or ortho-k lenses (randomly assigned to compression factor of either 0.75 or 1.75 D). Axial length and cycloplegic refraction were measured at six monthly intervals for two years by a masked examiner. The myopia control effectiveness was determined by axial elongation.
Results: A significant number of control (63 %) dropped out, mainly due to concern about myopia progression (58 %). A total of 75 participants (mean age: 9.3 ± 1.0 years; control: n = 11, ortho-k [0.75 D]: n = 29, ortho-k [1.75 D]: n = 35) completed the study. Considering ortho-k groups only, the mean axial elongation of participants wearing ortho-k lenses of conventional compression factor (0.75 D) and increased compression factor (1.75 D) were 0.53 ± 0.29 and 0.35 ± 0.29 mm, respectively, over the 2-year study period. The between-group differences in corneal health were not significant at all visits.
Conclusion: Participants wearing ortho-k lenses of increased compression factor further slowed axial elongation by 34%, when compared with the conventional compression factor without compromising corneal health. Further investigations are warranted to confirm the potential mechanism of an increased compression factor for improved myopia control effectiveness.
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http://dx.doi.org/10.1016/j.clae.2022.101745 | DOI Listing |
Sci Rep
January 2025
CSIRO Mineral Resources, Brisbane, QLD, 4069, Australia.
This paper investigates the impact of treatment with chemical solutions of varying pH values on the micro-macroscopic damage in coal samples under load, employing a combination of Small Angle X-ray Scattering (SAXS) experiments and uniaxial compression tests. The experimental results show that soaking coal samples in NaOH, HCl, and distilled water for 7 days leads to reductions in uniaxial compressive strength by 39.19%, 47.
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January 2025
School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology (IUST), P.O. Box 16844-13114, Tehran, Iran.
Surfactant chemistry can affect the phenolic foam (PF) properties by controlling the collision and combination of the created bubbles during foam production. The study was accomplished using two surfactant families, nonionic: polysorbate (Tween80) and anionic: sodium and ammonium lauryl sulfates (SLS30 and ALS70) and sodium laureth sulfate (SLES270) to manufacture PF foams. Tween80 and SLS30 resulted in foams with the lowest and highest densities, 20.
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January 2025
College of Mining, Liaoning Technical University, Fuxin, 123000, Liaoning, China.
With increasing mining depth, the coal pillars of a coal mine will be in a stressful environment characterized by high gas pressures and unidirectional loading. To investigate the damage evolution characteristics and energy evolution mechanism of coal pillars loaded in a gas pressure environment, a uniaxial compression test was performed on a coal body under different gas pressures using a load testing apparatus for gas-containing coal rocks. The obtained results showed that the mechanical properties of the coal body varied with the gas pressure.
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January 2025
School of petroleum engineering, Yangtze University, Wuhan, 430100, China.
Given the suboptimal physical properties and distinctive geological conditions of deep coalbed methane reservoirs, any reservoir damage that occurs becomes irreversible. Consequently, the protection of these deep coalbed methane reservoirs is of paramount importance. This study employs experimental techniques such as scanning electron microscopy, X-ray diffraction, and micro-CT imaging to conduct a comprehensive analysis of the pore structure, mineral composition, fluid characteristics, and wettability of coal seams 3# and 15# in the northern Qinshui Basin of China.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Novosibirsk State University, Pirogova 1, Novosibirsk 630090, Russian Federation.
High-pressure and low-temperature structural changes in the ferroelectric phase of (R)-3-quinuclidinol are analysed. The changes in unit-cell volume and parameters are continuous both on cooling and under increasing pressure. The anisotropy of the structural strain, however, is found to be different.
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