(n.) A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure.
Example Sentences:
(1) These results demonstrate that increased availability of galactose, a high-affinity substrate for the enzyme, leads to increased aldose reductase messenger RNA, which suggests a role for aldose reductase in sugar metabolism in the lens.
(2) Based on several previous studies, which demonstrated that sorbitol accumulation in human red blood cells (RBCs) was a function of ambient glucose concentrations, either in vitro or in vivo, our investigations were conducted to determine if RBC sorbitol accumulation would correlate with sorbitol accumulation in lens and nerve tissue of diabetic rats; the effect of sorbinil in reducing sorbitol levels in lens and nerve tissue of diabetic rats would be reflected by changes in RBC sorbitol; and sorbinil would reduce RBC sorbitol in diabetic man.
(3) The significance of the differences in these two patterns of actin is discussed in terms of differences in the accommodative ability and static lens shape in these two animals.
(4) The epithelium of Brunner's gland stained intensely with Ricinus communis agglutinin-I (RCA-I), succinylated-WGA (S-WGA) and wheat-germ agglutinin (WGA), moderately with Bandeirea simplicifolia agglutinin-I (BS-I), Concanavalia ensiformis agglutinin (Con A) peanut agglutinin (PNA) and Ulex europaeus agglutinin-I (UEA-I) and occasionally with Dolichos biflorus agglutinin (DBA), Lens culinaris agglutinin (LCA) and soybean agglutinin (SBA).
(5) That is, he believes, to look at massively difficult, interlocking problems through too narrow a lens.
(6) The advantages of the incision through the pars plana ciliaris are (1) easier approach to the vitreous cavity, (2) preservation of the crystalline lens and an intact iris, and (3) circumvention of the corneal and chamber angle complications sometimes associated with the transcorneal approach.
(7) The third patient was using an extended-wear soft contact lens for correction of residual myopia.
(8) The cellularity depends on the type of the lens and the material of the lens and on the clinical picture of the disease.
(9) Although lens haemagglutinins were detected in 6 out of 7 rabbits, in only 3 of the 6 animals did the titre reach a maximum of 1:640.
(10) Dioptric aniseikonia was calculated between 1 month and 24 months after surgery (with Gruber's and Huber's computer program) on the basis of most recently obtained values (bulb axis length, depth of the anterior chamber, lens thickness, necessary refraction), and compared with subjective measurements taken with the phase difference haploscope.
(11) We propose that a channel with these properties could contribute to maintenance of lens transparency and fluid balance.
(12) Although the lens did not alter stereopsis, it did produce severe color discrimination losses for normal and dichromatic subjects.
(13) The general efficacy of this intraocular lens compared with other anterior chamber lenses was not addressed in this study.
(14) However, the monkey lens low molecular weight proteins differ from the human low molecular weight proteins in charge as well as molecular weight determined by SDS-PAGE.
(15) Fifty-five myopic naval personnel with no previous contact lens experience were put through a three-week study using these contact lenses.
(16) A Stryker turning frame was used during surgical removal of a posterior displaced lens.
(17) The biocompatibility and fixation of a new silicone intraocular lens was evaluated in the cat eye.
(18) Both organisms have previously been found to be sequestered in the posterior lens capsule by histological and microbiological examination of excised capsular specimens.
(19) Previous experiments had demonstrated that the receptors for the lectins soybean agglutinin (SBA), wheat germ agglutinin, concanavalin A and Lens culinaris agglutinin all were relatively uniformly distributed on both myoblasts and myotubes, and that SBA receptors were capable of rapid redistribution on myotubes but not myoblasts at 4 degrees C (Sawyer & Akeson, 1983).
(20) The relative permittivity and conductivity of rabbit eye lens were measured in the frequency domain between 2 and 18 GHz at temperatures of 37 and 20 degrees C. An analysis of the data suggested that a significant proportion of the bulk water in nuclear and cortical lens tissue may behave differently to pure water.
Ocellus
Definition:
(n.) A little eye; a minute simple eye found in many invertebrates.
(n.) An eyelike spot of color, as those on the tail of the peacock.
Example Sentences:
(1) Each ocellus has a cuticular lens located on the distal end of a cuticular cone which encapsulates the receptor cells.
(2) It appears, therefore, that the graded receptor potential, which survives the application of tetrodotoxin, is responsible for mediating synaptic transmission in the ocellus.
(3) The receptory area of the ocellus terminates in a tapetum which contains granules, soluble in alcohol.
(4) A third type comes from the median ocellus and can be traced into the cervical connectives.
(5) This idea and alternatives have been tested on the barnacle lateral ocellus, a simple eye with only three photoreceptors, each with its own axon about 1 cm long.2.
(6) Membrane potential changes following illumination of a photoreceptor cell in the lateral ocellus of a barnacle (Balanus eburneus) were studied by means of intracellular recording and polarization techniques.
(7) The decay of the depolarizing and hyperpolarizing components of the visual signal was studied by recording intracellularly from single receptor axons of the median ocellus of the giant barnacle.2.
(8) Each ocellus has about 80 retinula cells whose axons project to corresponding ganglia from which 4 giant afferent interneurons (per ganglion) project to the brain.
(9) The visual pigment of each ocellus of mosquitoes reared in darkness was characterized by microspectrophotometry, and found to be the same.
(10) However, the two bilaterally positioned cells destined to become the pigment cells in the first step are still equipotent at this stage in that they can give rise to either the ocellus or otolith.
(11) Anatomically, the sensory cells of the dorsal ocellus of Tenodera were determined histologically to be grouped into two distinct regions, each group making its own separate contribution to the ocellar nerve.
(12) In the absence of this interaction, melanocyte specification proceeds along the dominant pathway that results in the differentiation of an ocellus.
(13) Five cells are accessory cells of the sensory structures: three lens cells and a pigment-cup cell in the ocellus, and a single pigment cell in the otolith.
(14) Of the remaining 79 cells, 36 are sensory, 17 receptors in the ocellus and 19 presumed hydrostatic pressure receptors; these lie on the right and left sides of the sensory vesicle, respectively.
(15) The light-evoked slow potential responses of the postsynaptic units are not altered by the application of tetrodotoxin to the ocellus.
(16) A small number of cells in the supraesophageal ganglion hyperpolarize when the median ocellus is illuminated and depolarize when it is shadowed.
(17) The spectral sensitivities of single Limulus median ocellus photoreceptors have been determined from records of receptor potentials obtained using intracellular microelectrodes.
(18) The spectral sensitivity curve for the repolarizing responses peaks at 480 nm; it is the only spectral sensitivity curve for a median ocellus electrical response known to peak at 480 nm.
(19) Our main conclusions are that: 1) the photoreceptors (retinular cells) of the lateral eye project only to the lamina; 2) the photoreceptors of the lateral rudimentary eye project to both the lamina and medulla; 3) the photoreceptors of the median ocellus project only to the ocellar ganglion; and 4) the photoreceptors of the rudimentary median (endoparietal) eye project to the ocellar ganglion and also into the optic tract.
(20) The view that the ocellus of the cockroach represents a degenerated structure can no longer be supported.