Adaptive, optical, radial basis function neural network for handwritten digit recognition.

An adaptive, optical, radial basis function classifier for handwritten digit recognition is experimentally demonstrated. We describe a spatially multiplexed system that incorporates an on-line adaptation of weights and basis function widths to provide robustness to optical system imperfections and system noise. The optical system computes the Euclidean distances between a 100-dimensional input vector and 198 stored reference patterns in parallel by using dual vector-matrix multipliers and a contrastreversing spatial light modulator. Software is used to emulate an electronic chip that performs the on-line learning of the weights and basis function widths. An experimental recognition rate of 92.7% correct out of 300 testing samples is achieved with the adaptive training, versus 31.0% correct for nonadaptive training. We compare the experimental results with a detailed computer model of the system in order to analyze the influence of various noise sources on the system performance.

Ultrastructure and function of oviduct-uterine junction in Ascaris suum (Nematoda).

Cells comprising the oviduct-uterine junction of the female reproductive tract in Ascaris suum were shown to have a distinctive ultrastructure. The free luminal surface of each epithelial cell was bordered by an electron-dense layer that measured 90 to 120 nm in thickness and could be removed by treatment with pronase. Numerous membrane-bound, filament-containing bodies were present in the cytoplasm near the apical margin. These filaments, measuring 6.5 nm in diameter, coalesce (or condense) to form a larger coiled, or homogeneous, electron-dense substance. These membrane-bound, filament-containing bodies often fused with the plasma membrane and released their contents into the lumen. In other instances, the filamentous arrangements were not membrane bound and remained within the cytoplasm where they formed electron-dense masses adjacent to the plasma membrane. Basal infoldings suggestive of water or ion transport occurred in each cell. Externally, the cells were bordered by a basement lamina and muscle cells.

Immunological studies of the relationship between the antigenic change of Ascaris oocytes and the junctional fluid of the fertilization chamber.

Antigenic change on the surface of immature oocytes of Ascaris occurred during passage through the oviduct. Using immunodiffusion and immunoelectrophoretic techniques we examined the possible relationship between the antigenic change of immature oocytes and the junctional fluid (JF) which is present in the fertilization chamber. From the immunodiffusion it was found that the anti-immature oocyte serum (A-I serum) had more immunoprecipitation arcs than did the anti-mature oocyte serum (A-M serum) when reacted against the junctional fluid. This indicated that A-I serum contained more immunoglobulins that reacted with junctional fluid than did the A-M serum. This result was substantiated by using immunoelectrophoretic analysis and two dimension crossed immunoelectrophoresis. Our results suggest that during the migration toward the oviduct-uterine junction the immature oocytes might shed surface proteins into the luminal fluid. Alternatively, the membrane surface of mature oocytes may be altered by the interaction with the substances present in the junctional fluid.

The function of microtubules during spermatogenesis of Ancylostoma caninum.

Ancylostoma caninum spermatogonia appeared as unspecialized cells with large nuclei and little cytoplasm when examined by electron microscopy. Mitochondria and ribosomes were numerous but endoplasmic reticulum of either the rough or smooth variety was rarely observed. Microtubules were abundant but were mostly concentrated in areas where the cells connected with a central cytoplasmic core, or rachis. Microtubules present elsewhere in the cytoplasm were not associated with any particular organelle. In spermatocytes, microtubules became numerous and formed the spindle apparatus during the rapid meiotic divisions. Following the meiotic divisions the nuclei of the resulting spermatids were devoid of a nuclear envelope, and the chromatin became highly condensed. At this time, the microtubules surrounded the elongating nucleus as it became confined to the tapering, posterior portion of the spermatid. These observations indicate that microtubules are involved in determining this final morphological appearance of Ancylostoma spermatids. However, there is no evidence to indicate the microtubules are assembled into motile organelles to be utilized by the ameboid in utero spermatozoa.

Development and fate of the membranous organelles in spermatozoa of Ancylostoma caninum.

During development membranous organelles first appeared in the primary spermatocytes of Ancylostoma. They were derived from the Golgi as two separate components. One component, an electron-dense spheroid, quickly fused with other newly-formed cup-shaped, membranous structures to form the asymmetrical organelles. Initially the membranous organelles had a homogeneous matrix but later became filled with quantities to 6- 8-nm filaments. Following the meiotic reduction divisions each cell assumed a bipolar configuration. The membranous organelles and mitochondria were confined to the broad anterior region while the non-membrane bound nucleus became located in the narrow posterior region. Golgi membranes, endoplasmic reticulum, and numerous ribosomes were sloughed from the main cell body. The filaments lost their association with the membranous organelles and attached to the plasma membrane while the membranous portion of each organelle became progressively more complex and assumed a peripheral position in the cytoplasm. The resulting spermatid, with its condensed, posteriorly-projected nucleus, and broad anterior cytoplasm, had a tadpolelike appearance. Subsequent to deposition in the female uterus the membranous organelles fused with the plasma membrane and the mature spermatozoa became pleomorphic and moved in an ameboid manner. Because the pseudopods in the mature cell originated in those areas where the filaments previously attached to the plasma membrane it is surmised that the filaments consist of, or contain, actin. The significance of the fusion of the membranous organelles with the sperm plasma membrane, however, remains unknown.

Ascaris oocytes: ultrastructural and immunocytochemical changes during passage through the oviduct.

Slender, bipolar, immature, Ascaris suum oocytes assume a smooth, spherical configuration as they traverse the oviduct. The present investigation was conducted to determine if this morphological alteration might be accompanied by changes in surface membranes. Immunocytochemical studies were conducted utilizing (1) fluorescein-labeled, sheep, anti-rabbit IgG, (2) Sternberger's unlabeled, antibody-enzyme technique, (3) ferritin-labeled, sheep, anti-rabbit IgG, and (4) an immunobead, labeled-antibody technique. These procedures clearly demonstrated that the surface of both immature and mature oocytes possessed different specific antigens. It is assumed that this acquisition of new antigens (or the loss of older ones) by the mature oocyte is somehow related to a conditioning phenomenon which prepares the oocyte for fertilization.

Structure and function of the glandular vas deferens in Ascaris suum (Nematoda).

The glandular vas deferens in the linearly arranged male reproductive tract in Ascaris suum produces substances which cause marked morphological and physiological changes in the spermatozoa. The glandular secretions, presumably formed by the rough endoplasmic reticulum and Golgi saccules, are extruded from the cells and coalesce to form homogeneous masses in the gland lumen. In sexually inactive worms the secretory material is separated from the spermatozoa by a sphincter comprised of neuro-muscular-like cells. During copulation the sphincter lumen enlarges and the spermatozoa and sperm-activating glandular material are mixed and simultaneously transferred to the female worm.

Rapid morphological transformations of spermatozoa in the uterus of Brugia pahangi (Nematoda, Filarioidea).

Mature, umated male and female Brugia pahangi worms were implanted into the peritoneal cavity of gerbils, allowed to mate, and then recovered and examined by means of electron microscopy. The proximal portion of the uterus of female worms recovered in copula contained a morphologically heterogenous population of sperm ranging from a rigid, nonmotile form to the mature ameboid sperm. The immotile sperm are identical in morphology to sperm found within the seminal vesicle of the male. The in utero transformations occur in less than 1 hr, and probably represent a final maturation event preceding competency to fertilize eggs. First in the sequence of events leading to the mature spermatozoon is a decrease in the density of the cytoplasmic matrix concomitant with the elaboration of an abundant tubular smooth endoplasmic reticulum. The position and appearance of the sperm in the uterus suggest that the formation of this membranous system occurs within minutes and involves de novo assembly from cytoplasmic precursors. Following the appearance of the tubular membranous system, certain other membranous organelles become spherical, fuse with the plasmalemma, and release their electron-dense contents into the lumen of the uterus. Filamentous rodlike elements, previously extending the length of the peripheral cytoplasm, begin to disintegrate and cytoplasmic projections form at the margins of the cell. Polarization of the sperm results from the aggregation of mitochondria, nuclear material, endoplasmic reticulum, and membranous organelles at one pole of the cell leaving an organelle-free filamentous pseudopod at the other.

Ribosomal RNA synthesis during cleavage of Ascaris lumbricoides eggs.

The appearance of well-defined nucleoli in 4-celled Ascaris embryos is associated with the synthesis of ribosomal RNA.

Zygote formation in Ascaris lumbricoides (Nematoda).

Ultrastructural observations of the in utero sperm of Ascaris lumbricoides reveal that it consists of a relatively clear, ameboid anterior region and a conical posterior region containing numerous surface membrane specializations, dense mitochondria, a lipid-like refringent body of variable size, and a dense nucleus which lacks an apparent nuclear envelope. No acrosomal complex was observed. Pseudopods emanating from the anterior cytoplasm make first contact with the primary oocytes and appear to be responsible for the localized removal of the extraneous coat covering the oolemma. Subsequently the gamete membranes interdigitate and finally fuse. Because this pseudopodial action appears similar to that reported for the acrosomal filaments in flagellated sperm, the anterior region of the Ascaris sperm is thought to serve an acrosomal function. Following gamete-membrane fusion, the sperm nucleus acquires a particulate appearance and becomes disorganized. Once inside the oocyte, the sperm cytoplasm consists of dense mitochondria, ribosomes, and vesicles derived from the surface membrane specializations. The refringent body, whose contents possibly contribute to the synthesis of ribosomes, is usually absent by the time the sperm cytoplasm attains a central position in the egg.