scholarly journals Anterior Scleral Regional Variation between Asian and Caucasian Populations

2020 ◽  
Vol 9 (11) ◽  
pp. 3419
Author(s):  
Alejandra Consejo ◽  
Richard Wu ◽  
Ahmed Abass
Keyword(s):  
Contact Lens ◽  
Regional Differences ◽  
Three Dimensional ◽  
Maximum Diameter ◽  
Temporal Region ◽  
Lens Design ◽  
Temporal Area ◽  
The Difference ◽  
Automated Technique ◽  
Processing Steps

Purpose: To evaluate the anterior scleral shape regional differences between Asian and Caucasian populations. Methods: The study included 250 Asian eyes and 235 Caucasian eyes from participants aged 22 to 67 years (38.5 ± 7.6). Three-dimensional (3D) corneo-scleral maps were acquired using a corneo-scleral topographer (Eye Surface Profiler, Eaglet Eye BV) and used to calculate sagittal height. For each 3D map, the sclera (maximum diameter of 18 mm) and cornea were separated at the limbus using an automated technique. Advanced data processing steps were applied to ensure levelled artefact-free datasets to build an average scleral shape map for each population. Results: Statistically, Asian and Caucasian sclerae are significantly different from each other in sagittal height (overall sclera, p = 0.001). The largest difference in sagittal height between groups was found in the inferior-temporal region (271 ± 203 µm, p = 0.03), whereas the smallest difference was found in the superior-temporal region (84 ± 105 µm, p = 0.17). The difference in sagittal height between Caucasian and Asian sclera increases with the distance from the limbus. Conclusions: Asian anterior sclera was found to be less elevated than Caucasian anterior sclera. However, the nasal area of the sclera is less elevated than the temporal area, independently of race. Gaining knowledge in race-related scleral topography differences could assist contact lens manufacturers in the process of lens design and practitioners during the process of contact lens fitting.

Polysensory properties of neurons in the anterior bank of the caudal superior temporal sulcus of the macaque monkey

1988 ◽  
Vol 60 (5) ◽  
pp. 1615-1637 ◽  
Author(s):  
K. Hikosaka ◽  
E. Iwai ◽  
H. Saito ◽  
K. Tanaka
Keyword(s):  
Visual Stimuli ◽  
Three Dimensional ◽  
Superior Temporal Gyrus ◽  
Superior Temporal Sulcus ◽  
Sensory Properties ◽  
Temporal Region ◽  
Directional Selectivity ◽  
Temporal Area ◽  
Response Properties ◽  
Visual Hemifield

1. We examined the sensory properties of cells in the anterior bank of the caudal part of the superior temporal sulcus (caudal STS) in anesthetized, paralyzed monkeys to visual, auditory, and somesthetic stimuli. 2. In the anterior bank of the caudal STS, there were three regions distinguishable from each other and also from the middle temporal area (MT) in the floor of the STS and area Tpt in the superior temporal gyrus. The three regions were located approximately in the respective inner, middle, and outer thirds of the anterior bank of the caudal STS. These three regions are referred to, from the inner to the outer, as the medial superior temporal region (MST), the mostly unresponsive region, and the caudal STS polysensory region (cSTP), respectively. 3. The extent of MST and its response properties agreed with previous studies. Cells in MST responded exclusively to visual stimuli, had large visual receptive fields (RFs), and nearly all (91%) showed directional selectivity. 4. In the mostly unresponsive region, three quarters of cells were unresponsive to any stimulus used in this study. A quarter of the cells responded to only visual stimuli and most did not show directional selectivity for moving stimuli. Several directionally selective cells responded to movements of three-dimensional objects, but not of projected stimuli. 5. The response properties of cells in the superficial cortex of the caudal superior temporal gyrus, a part of area Tpt, external to cSTP were different from those of cells in the three regions in the anterior bank of the STS. Cells in Tpt were exclusively auditory, and had much larger auditory RFs (mean = 271 degrees) than those of acoustically-driven cSTP cells (mean = 138 degrees). 6. The cSTP contained unimodal visual, auditory, and somesthetic cells as well as multimodal cells of two or all three modalities. The sensory properties of cSTP cells were as follows. 1) Out of 200 cells recorded, 102 (51%) cells were unimodal (59 visual, 33 auditory, and 10 somesthetic), 36 (18%) cells were bimodal (21 visual+auditory, 7 visual+somesthetic, and 8 auditory+somesthetic), and four (2%) cells were trimodal. Visual and auditory responses were more frequent than somesthetic responses: the ratio of the population of cells driven by visual: auditory: somesthetic stimuli was 3:2:1. 2) Visual RFs were large (mean diameter, 59 degrees), but two-thirds were limited to the contralateral visual hemifield. About half the cells showed directional selectivity for moving visual stimuli. None showed selectivity for particular visual shapes.(ABSTRACT TRUNCATED AT 400 WORDS)

Defocus ramp correction in spot-scan imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 130-131
Author(s):  
Kenneth H. Downing
Keyword(s):  
Computer Control ◽  
Three Dimensional ◽  
Sufficient Accuracy ◽  
Objective Lens ◽  
Electron Crystallography ◽  
Contrast Transfer Function ◽  
Tilt Axis ◽  
Specimen Height ◽  
The Difference ◽  
Envelope Functions

Three-dimensional structures of a number of samples have been determined by electron crystallography. The procedures used in this work include recording images of fairly large areas of a specimen at high tilt angles. There is then a large defocus ramp across the image, and parts of the image are far out of focus. In the regions where the defocus is large, the contrast transfer function (CTF) varies rapidly across the image, especially at high resolution. Not only is the CTF then difficult to determine with sufficient accuracy to correct properly, but the image contrast is reduced by envelope functions which tend toward a low value at high defocus.We have combined computer control of the electron microscope with spot-scan imaging in order to eliminate most of the defocus ramp and its effects in the images of tilted specimens. In recording the spot-scan image, the beam is scanned along rows that are parallel to the tilt axis, so that along each row of spots the focus is constant. Between scan rows, the objective lens current is changed to correct for the difference in specimen height from one scan to the next.

scholarly journals Regional differences in mortality rates during the COVID-19 epidemic in Italy

2020 ◽  
pp. 1-22
Author(s):  
Danila Azzolina ◽  
Giulia Lorenzoni ◽  
Luciano Silvestri ◽  
Ilaria Prosepe ◽  
Paola Berchialla ◽  
...  
Keyword(s):  
Regional Differences ◽  
Southern Italy ◽  
Meta Analysis ◽  
Analysis Data ◽  
Mortality Rates ◽  
Northern Italy ◽  
Admission Rates ◽  
Considerable Impact ◽  
The Difference ◽  
Disease Diffusion

Abstract Objective The COVID-19 outbreak started in Italy on February 20th, 2020, and has resulted in many deaths and intensive care unit (ICU) admissions. This study aimed to illustrate the epidemic COVID-19 growth pattern in Italy by considering the regional differences in disease diffusion during the first three months of the epidemic. Study design and methods Official COVID-19 data were obtained from the Italian Civil Protection Department of the Council of Ministers Presidency. The mortality and ICU admission rates per 100 000 inhabitants were calculated at the regional level and summarized via a Bayesian multilevel meta-analysis. Data were retrieved until April 21st, 2020. Results The highest cumulative mortality rates per 100 000 inhabitants were observed in northern Italy, particularly in Lombardia (85.3, 95% credibility intervals [CI] 75.7–94.7). The difference in the mortality rates between northern and southern Italy increased over time, reaching a difference of 67.72 (95% CI = 66–67) cases on April 2nd. Conclusions Northern Italy showed higher and increasing mortality rates during the first three months of the epidemic. The uncontrolled virus circulation preceding the infection spreading in southern Italy had a considerable impact on system burnout. This experience demonstrates that preparedness against the pandemic is of crucial importance to contain its disruptive effects.

The iron content of iron superoxide dismutase: determination by anomalous scattering

1983 ◽  
Vol 218 (1210) ◽  
pp. 119-126 ◽  
Keyword(s):  
Superoxide Dismutase ◽  
Iron Content ◽  
Three Dimensional ◽  
Anomalous Scattering ◽  
Total Iron Content ◽  
Iron Site ◽  
Iron Superoxide Dismutase ◽  
Density Map ◽  
The Difference ◽  
Electron Density Map

The number of iron atoms in the dimeric iron-containing superoxide dismutase from Pseudomonas ovalis and their atomic positions have been determined directly from anomalous scattering measurements on crystals of the native enzyme. To resolve the long-standing question of the total amount of iron per molecule for this class of dismutase, the occupancy of each site was refined against the measured Bijvoet differences. The enzyme is a symmetrical dimer with one iron site in each subunit. The iron position is 9 ņ from the intersubunit interface. The total iron content of the dimer is 1.2±0.2 moles per mole of protein. This is divided between the subunits in the ratio 0.65:0.55; the difference between them is probably not significant. Since each subunit contains, on average, slightly more than half an iron atom we conclude that the normal state of this enzyme is two iron atoms per dimer but that some of the metal is lost during purification of the protein. Although the crystals are obviously a mixture of holo- and apo-enzymes, the 2.9 Å electron density map is uniformly clean, even at the iron site. We conclude that the three-dimensional structures of the iron-bound enzyme and the apoenzyme are identical.

Utility of a semi-scleral contact lens design in the management of the irregular cornea

2013 ◽  
Vol 36 (3) ◽  
pp. 146-150 ◽  
Author(s):  
Miguel Romero-Jiménez ◽  
Patricia Flores-Rodríguez
Keyword(s):  
Contact Lens ◽  
Lens Design

scholarly journals SPECTRAL CORRELATIONS IN DISORDERED MESOSCOPIC METALS AND THEIR RELEVANCE FOR PERSISTENT CURRENTS

1996 ◽  
Vol 10 (28) ◽  
pp. 1397-1406 ◽  
Author(s):  
AXEL VÖLKER ◽  
PETER KOPIETZ
Keyword(s):  
Energy Levels ◽  
Three Dimensional ◽  
Average Density ◽  
Electron Interaction ◽  
Energy Window ◽  
Persistent Currents ◽  
Dependent Part ◽  
The Difference ◽  
Aharonov Bohm ◽  
Grand Canonical

We use the Lanczos method to calculate the variance σ2(E, ϕ) of the number of energy levels in an energy window of width E below the Fermi energy for noninteracting disordered electrons on a thin three-dimensional ring threaded by an Aharonov–Bohm flux ϕ. We confirm numerically that for small E the flux-dependent part of σ2(E, ϕ) is well described by the Altshuler–Shklovskii-diagram involving two Cooperons. However, in the absence of electron–electron interactions this result cannot be extrapolated to energies E where the energy-dependence of the average density of states becomes significant. We discuss consequences for persistent currents and argue that for the calculation of the difference between the canonical- and grand canonical current it is crucial to take the electron–electron interaction into account.

Evolution of Stress During Formation of Titanium Disilicide by Rta and Tube Furnace Annealing

1990 ◽  
Vol 202 ◽  
Author(s):  
J.F. Jongste ◽  
O.B. Loopstra ◽  
G.C.A.M. Janssen ◽  
S. Radelaar
Keyword(s):  
Integrated Circuit ◽  
Thermal Processing ◽  
Reaction Rates ◽  
Titanium Disilicide ◽  
Furnace Annealing ◽  
Integrated Circuit Fabrication ◽  
Annealing Step ◽  
Circuit Fabrication ◽  
The Difference ◽  
Processing Steps

Integrated circuit fabrication consists of many processing steps: e.g. lithography, etching, implantation and metallization. Some of these processes are combined with thermal processing. Heat treatments require special attention because previous fabrication steps may be influenced: e.g. dopant profiles may be deteriorated. The amount of interference of an annealing step with a former process is determined by the ratio of the reaction rates (and hence by the difference in activation energies).

Theory of ultrasonic attenuation in one and two dimensional metals

1976 ◽  
Vol 54 (14) ◽  
pp. 1454-1460 ◽  
Author(s):  
T. Tiedje ◽  
R. R. Haering
Keyword(s):  
Ultrasonic Attenuation ◽  
Three Dimensional ◽  
Electronic Systems ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
One Dimensional ◽  
The Difference

The theory of ultrasonic attenuation in metals is extended so that it applies to quasi one and two dimensional electronic systems. It is shown that the attenuation in such systems differs significantly from the well-known results for three dimensional systems. The difference is particularly marked for one dimensional systems, for which the attenuation is shown to be strongly temperature dependent.

The Measurement of Stresses in Composites

1986 ◽  
Vol 1 (2) ◽  
pp. 15-21 ◽  
Author(s):  
J. B. Cohen
Keyword(s):  
Three Dimensional ◽  
Stress System ◽  
Principal Stresses ◽  
Reasonable Time ◽  
Complete Measurement ◽  
Useful Life ◽  
Diffraction Peaks ◽  
The Difference ◽  
Full Investigation ◽  
Hydrostatic Component

AbstractAlthough there is mounting interest in the measurement of stresses in composite materials after fabrication and/or use, few measurements to date have not taken into account the three dimensional nature of the stress system in such materials. Most data give only the net stress, that is, the difference between principal stresses. A procedure for a more complete measurement (in a reasonable time) is developed here, including the separation of macrostresses and microstresses. If time does not permit a full investigation, measurements of the lattice parameters of the component phases provide a simple way to sample the hydrostatic component due to differential thermal contraction. The Barrett-Predecki method of adding filler is particularly promising for stress measurements in those composites whose component phases do not give appropriate diffraction peaks. This procedure could also be used for monitoring stresses during the useful life of such materials.

Chemical Stress Relaxation of NR Networks Prepared in the Swollen State

1986 ◽  
Vol 59 (4) ◽  
pp. 541-550 ◽  
Author(s):  
Kyung-Do Suh ◽  
Hidetoshi Oikawa ◽  
Kenkichi Murakami
Keyword(s):  
Stress Relaxation ◽  
Network Structure ◽  
Three Dimensional ◽  
Polymer Chains ◽  
Chemical Stress ◽  
Network Chain ◽  
Crosslinking Process ◽  
Dimensional Network ◽  
Chemical Relaxation ◽  
The Difference

Abstract From the experimental results of the present investigation, it is apparent that two kinds of networks which have a different three-dimensional network structure give quite different behavior of chemical stress relaxation, even if both networks have the same network chain density. The difference in three-dimensional network structure for the two kinds of rubber arises from the degree of entanglement, which changes with the concentration of the polymer chains prior to the crosslinking process. The direct cause of chemical relaxation is due to the scission of network chains by degradation, whereas the total relaxation is caused by the change of geometrical conformation of network chains. This then casts doubt on the basic concept of chemorheology which is represented by Equation 2.

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