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Purpose To study the effects of different axial lengths on ultra-widefield imaging to determine the presence of distortion in images despite software correction and calculate an enlargement factor based on angular location. Design Experimental image analysis study. Study Objects Three 3-dimensional printed model eyes simulating eyes with axial lengths of 22, 24, and 26 mm. Each model has a grid of rings 9° apart centered at the posterior pole. Methods Single-center study performed at the National Institute for Health Research Moorfields Biomedical Research Centre (London, UK). Each model was imaged using Optos 200TX (Optos, Dunfermline, UK). Two images for each model eye that were corrected using V2 Vantage Pro software (Optos) were used for analysis and the average values obtained. Each image inter-ring area was measured using ImageJ to obtain a measured image area in pixel and square millimeters. This was compared with the true calculated object inter-ring area and an enlargement factor was determined. Main Outcome Measures Measured image inter-ring area in pixels and square millimeters. True calculated object inter-ring area in square millimeters. Results The enlargement factor of the rings gradually increases toward the periphery with factors of 1.4 at 45° and 1.9 at the equator. The axial lengths did not affect the enlargement factor of the rings imaged in 3 different model eyes (P = 0.9512). The anterior equator exhibits a significant distortion despite the software correction. Conclusion The enlargement factor depends on angular location and not axial length. The enlargement factors can be used in clinical practice to more accurately measure area in ultra-widefield imaging.

To assess glaucomatous damage to the lateral geniculate nucleus of the thalamus, as well as to its magnocellular and parvocellular layers, we examined the autopsy sections of the lateral geniculate nucleus of individuals with and without glaucoma. Five patients with a documented history of glaucoma and five controls with no ophthalmic or chronic central nervous system disease were included in this study. Neurons were counted in autopsy sections of the lateral geniculate nucleus. Cells were counted in 40 random microscopic fields of the magnocellular and parvocellular layers respectively. The mean magnocellular cell density for the glaucoma group of 2.72 ± 0.13 cells per square millimeter (mean ± SEM) was significantly less than that for the control group of 3.76 ± 0.13 cells per square millimeter (P

The erosion rates (expressed as grams per square millimeter per minute) of three casing steels (P110, N80 and K55) and hot-rolled 1020 steel in quartz sand-oil suspensions, GFN 140, solids loading 0.5–4 wt.%, at speeds from 9.35 to 18.7 m s −1 have been measured in a slurry pot tester. The velocity exponent was determined as 2.4 and the relationship of erosion rate to solids loading and particle size (for the particle size range 53–180 μm) determined. The erosion rates for all the steels were found to lie within a scatter band of ±15% and could not be related predictively with the measured tensile properties. Results are discussed in terms of the rate of particle impact on the eroding target and the need to control flow conditions through appropriate design to minimize erosion.

We have fabricated and studied superconducting wire networks with various geometrical properties including fractal, periodic, quasi-periodic, and random. We will discuss design and fabrication of these aluminum networks, which consist of nearly one million elements and span a square millimeter. We will present results of several studies of these networks.

The number of myelinated fibers per square millimeter of fasciculus gracilis, and of large and small myelinated fibers per square millimeter of fasciculus gracilis, at the C3 and T5 segements of spinal cord from 22 persons of different ages have been estimated, with a 95% confidence limit, assisted by semi-automatic methods of measurement and using programmed calculation and plotting. In addition, the histograms for diameter of myelinated fibers and mean diameter were obtained. At C3, the numbers of myelinated fibers ranged from 19,647/mm2 to 35,773/mm2, with a mean of 25,267/mm2. The number is less with older age. At T5, numbers of myelinated fibers ranged from 17,804/mm2 to 29,486/mm2, with a mean of 23,069/mm2. The number of myelinated fibers was greater at C3 than at T5 in subjects under 45. The mean diameter of myelinated fibers at C3 was smaller than that at T5. The normative data presented here should be useful for comparing with similarly derived data from patients with diseases of peripheral nerves, in evaluating the three-dimensional morphologic alteration of primary afferent neurons.

Image quality is limited by the information capacity of the image-forming system and can be computed from three parameters: contrast, resolution, and noise. These parameters can be combined to yield a single measure which determines the maximum amount of information obtainable from any x-ray system and is called the noise-equivalent number of quanta (NEQ) per unit area. The effects of image quality, expressed as noise-equivalent number of quanta (NEQ) per unit area, on the radiographic performance by dentists reading the position of an endodontic file in a root canal were studied. Three different speed films were used in conjunction with a fixed screen. NEQ values ranged between 0.64 × 10 4 and 14.3 × 10 4 per square millimeter. Components of variance associated with the position of the tooth apex and the tip of an endodontic file in a root canal were compared for the effect of different NEQs and observers. Results show that the standard deviation in locating a file tip and tooth apex may be a linear function of log NEQ. The estimated standard deviation associated with changes in NEQ was found to be relatively small compared to that observed among dentists. These findings indicate that a significant reduction in exposure would have a relatively small effect on the precision of endodontic distance measurements.

Samples from the center of a wide-field specular micrograph adequately assessed cell density and frequency distribution of cell areas. A preliminary analysis of the spread of values indicated whether an increased sample size was required. An algorithm determined how large a sample taken from the central photogreaph (three, five, or nine rectangles) was necessary to permit detection of a 10% change in cell area. This analysis of sample size also indicated that sampling by small-field specular microscopy was not representative of the surrounding square millimeter of corneal endothelium.

It has been suggested that patients who present with episodes of unexplained anaphylaxis (UEA) or unexplained flushing (UEF) have systemic mastocytosis (SM), a proposal believed to be supported by the presence of excess mast cell (MC) numbers in the skin of these individuals. To examine this hypothesis, we determined the number and distribution of MCs in the skin of nine normal subjects, nine patients with UEA/UEF, six patients with urticaria pigmentosa (UP), and 14 patients with SM. Skin biopsy specimens of normal subjects contained 38.4 +/- 4 (mean +/- SEM) MCs per square millimeter. Biopsy specimens of patients with UEA/UEF contained 71.8 +/- 13 MCs per square millimeter. Although the numbers were significantly different from numbers in skin of normal subjects (p less than 0.05), similar modest increases in MC numbers are observed in a number of skin conditions. In marked contrast, lesional biopsy specimens of patients with UP contained 596.5 +/- 278 MCs per square millimeter (p less than 0.05, n = 6, compared to MC numbers in the skin of normal subjects), and patients with SM had 720.6 +/- 176 MCs per square millimeter in lesional skin (p less than 0.01, n = 12, compared to normal skin). Patients with UP or SM also had increased MC numbers in nonlesional skin compared to normal skin (168.0 MCs per square millimeter, p less than 0.05, n = 5, and 184.4 MCs per square millimeter, p less than 0.01, n = 10, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Anthocyanin formation by Spirodela oligorrhiza has been determined as a function of irradiance. The highest yields resulted when the plants were incubated for 40 hours in the dark after irradiation. Saturation was reached in the red at about 20 k.ergs (1.3 × 10 −8 Einsteins) per square millimeter. The irradiance response curve for white fluorescent light, however, did not reach saturation at the highest values applied, namely 600 kiloergs per square millimeter, and possible explanations for this behavior are discussed. Using irradiances within the proportionality range, and calibrated intensities of monochromatic light from a high energy arc in a grating spectrograph, the action spectrum for anthocyanin synthesis was determined. The band widths for each point were less than 4 mμ. The resulting spectrum shows sharp peaks at 705 and (when number of fronds is used as parameter) at 300 mμ. The latter band in the ultraviolet has not yet been reported in other plants. Both blue and green light were relatively ineffective. In spite of many attempts, no evidence for control of anthocyanin formation by a red: far-red reversible system could be obtained.

This year a new low-cost ($7000) semi-automatic counting system has become available from Image Technology, Inc. of Deer Park, New York. Tracks in CR-39 from proton recoils, either chemically etched or electro-chemically etched, can easily be counted when the system's video camera is coupled to an optical microscope with a low-power objective. An area of one square millimeter can be counted in less than three seconds.