In the tiger salamander retina, visual signals are transmitted to the inner retina via six morphologically distinct types of photoreceptors: large/small rods, large/small single cones, and double cones composed of principal and accessory members. The objective of this study was to determine the morphology of these photoreceptors and their synaptic interconnection with bipolar cells and horizont...

PURPOSE Small-field dosimetry is challenging, and the main limitations of most dosimeters are insufficient spatial resolution, water nonequivalence, and energy dependence. The purpose of this study was to compare plastic scintillation detectors (PSDs) to several commercial stereotactic dosimeters by measuring total scatter factors and dose profiles on a CyberKnife system. METHODS Two PSDs wer...

We have labeled the growth cones of retinal ganglion cell axons with HRP in intact mouse embryos. This has allowed us to visualize growth cone morphology during outgrowth along an entire CNS pathway from origin to target; to ask whether growth cone forms, and thus behaviors, differ at various points along the pathway; and to study the relationships of growth cones with the cellular environment....

We have previously used retinal and sympathetic explants to show that growth cones recognize and retract from specific neurites in culture (Kapfhammer et al., 1986). In an effort to determine the generality of this phenomenon and to see how many different neurite labels can be detected by it, we have studied interactions between individual growth cones and neurites extending from a variety of n...

P. E. Larson, P. T. Gurney, D. G. Nishimura Electrical Engineering, Stanford University, Stanford, CA, United States Introduction Radial imaging, or projection reconstruction (PR), acquires data on radial spokes, enabling short TEs as well as being robust to motion, making it suitable for short-T2 and dynamic imaging applications. It requires longer scan times than Cartesian trajectories for th...

Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to t...

Hyperbolicity cones are convex algebraic cones arising from hyperbolic polynomials. A well-understood subclass of hyperbolicity cones is that of spectrahedral cones and it is conjectured that every hyperbolicity cone is spectrahedral. In this paper we prove a weaker version of this conjecture by showing that every smooth hyperbolicity cone is the linear projection of a spectrahedral cone, that ...

This paper describes the fabrication of arrays of spherical microlenses by self-assembly of microspheres and the use of these arrays for nearfield photolithography to generate repetitive microstructures in photoresist. We used these arrays of microspheres to fabricate two types of elastomeric membranes: (i) membranes that have microspheres embedded in their surface and (ii) membranes that have ...

Neurons were grown on plastic surfaces that were untreated, or treated with polylysine, laminin, or L1 and their growth cones were detached from their culture surface by applying known forces with calibrated glass needles. This detachment force was taken as a measure of the force of adhesion of the growth cone. We find that on all surfaces, lamellipodial growth cones require significantly great...