Anisometropia represents a unique example of ocular development, where the two eyes of an individual, with an identical genetic background and seemingly subject to identical environmental influences, ...can grow asymmetrically to produce significantly different refractive errors. This review provides an overview of the research examining myopic anisometropia, the ocular characteristics underlying the condition and the potential aetiological factors involved. Various mechanical factors are discussed, including corneal structure, intraocular pressure and forces generated during near work that may contribute to development of anisomyopia. Potential visually guided mechanisms of unequal ocular growth are also explored, including the influence of astigmatism, accommodation, higher-order aberrations and the choroidal response to altered visual experience. The association between binocular vision, ocular dominance and asymmetric refraction is also considered, along with a review of the genetic contribution to the aetiology of myopic anisometropia. Despite a significant amount of research into the biomechanical, structural and optical characteristics of anisometropic eyes, there is still no unifying theory, which adequately explains how two eyes within the same visual system grow to different endpoints.
In 2018, a set of entrustable professional activities (EPAs) and procedural skills assessments were developed for anesthesiology training, but they did not assess all the Accreditation Council for ...Graduate Medical Education (ACGME) milestones. The aims of this study were to (1) remap the 2018 EPA and procedural skills assessments to the revised ACGME Anesthesiology Milestones 2.0, (2) develop new assessments that combined with the original assessments to create a system of assessment that addresses all level 1 to 4 milestones, and (3) provide evidence for the validity of the assessments.
Using a modified Delphi process, a panel of anesthesiology education experts remapped the original assessments developed in 2018 to the Anesthesiology Milestones 2.0 and developed new assessments to create a system that assessed all level 1 through 4 milestones. Following a 24-month pilot at 7 institutions, the number of EPA and procedural skill assessments and mean scores were computed at the end of the academic year. Milestone achievement and subcompetency data for assessments from a single institution were compared to scores assigned by the institution's clinical competency committee (CCC).
New assessment development, 2 months of testing and feedback, and revisions resulted in 5 new EPAs, 11 nontechnical skills assessments (NTSAs), and 6 objective structured clinical examinations (OSCEs). Combined with the original 20 EPAs and procedural skills assessments, the new system of assessment addresses 99% of level 1 to 4 Anesthesiology Milestones 2.0. During the 24-month pilot, aggregate mean EPA and procedural skill scores significantly increased with year in training. System subcompetency scores correlated significantly with 15 of 23 (65.2%) corresponding CCC scores at a single institution, but 8 correlations (36.4%) were <30.0, illustrating poor correlation.
A panel of experts developed a set of EPAs, procedural skill assessment, NTSAs, and OSCEs to form a programmatic system of assessment for anesthesiology residency training in the United States. The method used to develop and pilot test the assessments, the progression of assessment scores with time in training, and the correlation of assessment scores with CCC scoring of milestone achievement provide evidence for the validity of the assessments.
Purpose. To investigate static upper eyelid pressure and contact with the ocular surface in a group of young adult subjects. Methods. Static upper eyelid pressure was measured for 11 subjects using a ...piezoresistive pressure sensor attached to a rigid contact lens. Measures of eyelid pressure were derived from an active pressure cell (1.14-mm square) beneath the central upper eyelid margin. To investigate the contact region between the upper eyelid and the ocular surface, the authors used pressure-sensitive paper and the lissamine-green staining of Marx's line. These measures, combined with the pressure sensor readings, were used to derive estimates of eyelid pressure. Results. The mean contact width between the eyelids and the ocular surface estimated using pressure-sensitive paper was 0.60 +/- 0.16 mm, whereas the mean width of Marx's line was 0.09 +/- 0.02 mm. The mean central upper eyelid pressure was calculated to be 3.8 +/- 0.7 mm Hg (assuming that the whole pressure cell was loaded), 8.0 +/- 3.4 mm Hg (derived using the pressure-sensitive paper imprint widths), and 55 +/- 26 mm Hg (based on contact widths equivalent to Marx's line). Conclusions. The pressure-sensitive paper measurements suggested that a band of the eyelid margin, significantly larger than the anatomic zone of the eyelid margin known as Marx's line, had primary contact with the ocular surface. Using these measurements as the contact between the eyelid margin and the ocular surface, the authors believe that the mean pressure of 8.0 +/- 3.4 mm Hg is the most reliable estimate of static upper eyelid pressure.
A new family of highly active ethylene tri-/tetramerization catalysts based on N-phosphinoamidinechromium complexes has been investigated. The 1-hexene to 1-octene molar ratio can be tuned from 140 ...to 1.5 by varying the steric environment around the chromium center, and product purities are very good to excellent. Precatalyst tridentate coordination effectively shuts down catalytic activity, suggesting that THF abstraction from the chromium center by the Lewis acidic aluminum activator is necessary to achieve an active catalyst system.
Infrared spectroscopic imaging provides micron-scale spatial resolution with molecular contrast. While recent work demonstrates that sample morphology affects the recorded spectrum, considerably less ...attention has been focused on the effects of the optics, including the condenser and objective. This analysis is extremely important, since it will be possible to understand effects on recorded data and provides insight for reducing optical effects through rigorous microscope design. Here, we present a theoretical description and experimental results that demonstrate the effects of commonly-employed cassegranian optics on recorded spectra. We first combine an explicit model of image formation and a method for quantifying and visualizing the deviations in recorded spectra as a function of microscope optics. We then verify these simulations with measurements obtained from spatially heterogeneous samples. The deviation of the computed spectrum from the ideal case is quantified via a map which we call a deviation map. The deviation map is obtained as a function of optical elements by systematic simulations. Examination of deviation maps demonstrates that the optimal optical configuration for minimal deviation is contrary to prevailing practice in which throughput is maximized for an instrument without a sample. This report should be helpful for understanding recorded spectra as a function of the optics, the analytical limits of recorded data determined by the optical design, and potential routes for optimization of imaging systems.
To investigate associations between the topography of the cornea and the morphology of the eyelids in a population of young adult subjects with a range of refractive errors.
Corneal topography data ...and digital images of the anterior eye were acquired for 100 young adult subjects. The corneal topography data and palpebral fissure images were analyzed to determine a range of parameters describing the shape of the cornea and the morphology of the palpebral fissure. Correlation analysis was carried out to investigate for significant associations between the parameters describing the topography of the cornea and the parameters describing the morphology of the palpebral fissure.
A number of highly significant correlations were found between the best-fitting corneal spherocylinder and the eyelid morphology parameters. The corneal best-fit sphere (M) was significantly correlated with the horizontal palpebral fissure width (r = -0.428; P < 0.001). Corneal astigmatism power vector J45 was significantly correlated with the angle of the palpebral fissure (r = 0.392; P < 0.001). The axis of corneal astigmatism was also found to be significantly correlated with the angle of the palpebral fissure (r = 0.317; P = 0.005).
A number of significant associations exist between the corneal spherocylinder and the morphology of the eyelids in a normal adult population.
A family of chromium complexes bearing tridentate pyridine-based ligands are disclosed as highly active precatalysts for the oligomerization of ethylene. The ligands are comprised of two distinct ...types: Type 1, in which both ketone groups of 2,6-diacetylpyridine are converted to imines to produce pyridine bisimine NNN ligands; and Type 2, in which only one ketone group of 2,6-diacetylpyridine is condensed with an aniline derivative to give monoimine NNO coordination sets. Ligands of either type are coordinated to chromium(II) or chromium(III) chlorides, and activation of the resultant complexes with methylaluminoxane (MAO) produces highly active ethylene oligomerization and polymerization catalysts. Catalysts of Type 1 (NNN set) generally produce 1-butene when only two ortho alkyl substituents are present but switch to making waxes or polyethylene when the size and/or number of ortho substituents are increased. Catalysts of Type 2 (NNO set) produce waxes and polyethylene under all of the substitution patterns studied. The butene-producing catalysts can make 1-butene with 99.5+% purity, and the wax-producing catalysts make highly linear to moderately branched waxes, depending on the presence of an α-olefin comonomer.
There is great interest in assessing the in vivo toxicity of chemicals using nonanimal alternatives. However, acute mammalian toxicity is not adequately predicted by current in silico or in vitro ...approaches. Mechanisms of acute toxicity are likely conserved across invertebrate, aquatic, and mammalian species, suggesting that dose-response concordance would be high and in vitro mechanistic data could predict responses in multiple species under conditions of similar bioavailability. We tested this hypothesis by comparing acute toxicity between rat, daphnia, and fish and by comparing their respective acute data to inhibition of mitochondria membrane potential (MMP) using U.S. Environmental Protection Agency ToxCast in vitro high-throughput screening data. Logarithmic scatter plots of acute toxicity data showed a clear relationship between fish, daphnia, and intravenous rat but not oral rat data. Similar plots versus MMP showed a well-delineated upper boundary for fish, daphnia, and intravenous data but were scattered without an upper boundary for rat oral data. Adjustments of acute oral rat toxicity values by simulating fractional absorption and CYP-based metabolism as well as removing compounds with hydrolyzable linkages or flagged as substrates for glucuronidation delineated an upper boundary for rat oral toxicity versus MMP. Mitochondrial inhibition at low concentrations predicted highly acutely toxic chemicals for fish and daphnia but not the rat where toxicity was often attenuated. This use of a single high-throughput screening assay to predict acute toxicity in multiple species represents a milestone and highlights the promise of such approaches but also the need for refined tools to address systemic bioavailability and the impact of limited absorption and first pass metabolism.
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