Neurofascin induces neurites by heterophilic interactions with axonal NrCAM while NrCAM requires F11 on the axonal surface to extend neurites

Neurofascin and NrCAM are two axon-associated transmembrane glycoproteins belonging to the L1 subgroup of the Ig superfamily. In this study, we have analyzed the interaction of both proteins using neurite outgrowth and binding assays. A neurofascin-Fc chimera was found to stimulate the outgrowth of tectal cells when immobilized on an inert surface but not as a soluble form using polylysine as substrate. Antibody blocking experiments demonstrate that neurite extension on immobilized neurofascin is mediated by NrCAM on the axonal surface. Under the reverse experimental conditions where NrCAM induces neurite extension, F11, and not neurofascin, serves as axonal receptor. Binding studies using transfected COS7 cells and immunoprecipitations reveal a direct interaction between neurofascin and NrCAM. This binding activity was mapped to the Ig domains within neurofascin. The neurofascin-NrCAM binding can be modulated by alternative splicing of specific stretches within neurofascin. These studies indicate that heterophilic interactions between Ig-like proteins implicated in axonal extension underlie a regulation by the neuron

Von Meyenburg Complex or Liver Metastasis? Case Report and Literature Review

Hepatic lesions represent a common finding in clinical practice. Bile ducts hamartomas, also known as Von Meyenburg complex, are benign hepatic malformations composed of small dilated cystic bile ducts lined by fibrous stroma. They represent a rare and asymptomatic clinic-pathological entity. Imagiological findings are variable, and may present as multiple small scattered lesions, or rarely as a single nodule. These findings may resemble secondary lesions and, although benign, there are cases of progression to colangiocarcinoma. Thus it is important to include this complex in the differential diagnoses of focal hepatic lesions, being necessary a detailed investigation for their differentiation. This case represents an atypical presentation of a rare and not frequently considered entity in clinical practic

Ground state correlations and mean-field in 16^{16}O

We use the coupled cluster expansion ($\exp(S)$ method) to generate the complete ground state correlations due to the NN interaction. Part of this procedure is the calculation of the two-body G matrix inside the nucleus in which it is being used. This formalism is being applied to $^{16}O$ in a configuration space of 50 $\hbar\omega$. The resulting ground state wave function is used to calculate the binding energy and one- and two-body densities for the ground state of $^{16}O$.Comment: 9 pages, 9 figures, LaTe

An optical threshold function based on polarization rotation in a single semiconductor optical amplifier

Optical threshold functions are a basic building block for alloptical signal processing, and this paper investigates a threshold function design reliant on a single active element. An optical threshold function based on nonlinear polarization rotation in a single semiconductor optical amplifier is proposed. It functions due to an induced modification of the birefringence of a semiconductor optical amplifier caused by an externally injected optical control signal. It is shown that switching from both the TE to the TM mode and vice versa is possible. The measured results are supported by simulation results based on the SOA rate equations. ©2007 Optical Society of Americ

A Measurement of Stimulated Emission From 83m-Kr(m)

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Plastic strain arrangement in copper single crystals in sliding

Deformation of tribologically loaded contact zone is one of the wear mechanisms in spite of the fact that no mass loss may occur during this process. Generation of optimal crystallographic orientations of the grains in a polycrystalline materials (texturing) may cause hardening and reducing the deformation wear. To reveal the orientation dependence of an individual gain and simplify the task we use copper single crystals with the orientations of the compression axis along [11 1] and [110]. The plastic deformation was investigated by means of optical, scanning electron microscopy and EBSD techniques. It was established that at least four different zones were generated in the course of sliding test, such as non-deformed base metal, plastic deformation layer sliding, crystalline lattice reorientation layer and subsurface grain structure layer. The maximum plastic strain penetration depth was observed on [110]-single crystals. The minimum stability of [11 1]-crystals with respect to rotation deformation mode as well as activation of shear in the sliding contact plane provide for rotation deformation localization below the worn surface. The high-rate accumulation of misorientations and less strain penetration depth was observed on [11 1]-crystals as compared to those of [110]-oriented ones

A Measurement of Parity-Violating Neutron Transmission in Xenon

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Neutron Drops and Skyrme Energy-Density Functionals

The J$^{\pi}$=0$^+$ ground state of a drop of 8 neutrons and the lowest 1/2$^-$ and 3/2$^-$ states of 7-neutron drops, all in an external well, are computed accurately with variational and Green's function Monte Carlo methods for a Hamiltonian containing the Argonne $v_{18}$ two-nucleon and Urbana IX three-nucleon potentials. These states are also calculated using Skyrme-type energy-density functionals. Commonly used functionals overestimate the central density of these drops and the spin-orbit splitting of 7-neutron drops. Improvements in the functionals are suggested

FAST CARS: Engineering a Laser Spectroscopic Technique for Rapid Identification of Bacterial Spores

Airborne contaminants, e.g., bacterial spores, are usually analyzed by time consuming microscopic, chemical and biological assays. Current research into real time laser spectroscopic detectors of such contaminants is based on e.g. resonant Raman spectroscopy. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. The connection with previous studies based on "Coherent Anti-Stokes Raman Spectroscopy" (CARS) is to be noted. However generating and utilizing maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is much more challenging. This extension of the CARS technique is called FAST CARS (Femtosecond Adaptive Spectroscopic Techniques for Coherent Anti-Stokes Raman Spectroscopy), and the present paper proposes and analyses ways in which it could be used to rapidly identify pre-selected molecules in real time.Comment: 43 pages, 21 figures; replacement with references added. Submitted to the Proceedings of National Academy of Science

Many-body effects in 16O(e,e'p)

Effects of nucleon-nucleon correlations on exclusive $(e,e'p)$ reactions on closed-shell nuclei leading to single-hole states are studied using $^{16}O(e,e'p)^{15}N$ ($6.32$ MeV, $3/2^-$) as an example. The quasi-hole wave function, calculated from the overlap of translationally invariant many-body variational wave functions containing realistic spatial, spin and isospin correlations, seems to describe the initial state of the struck proton accurately inside the nucleus, however it is too large at the surface. The effect of short-range correlations on the final state is found to be largely cancelled by the increase in the transparency for the struck proton. It is estimated that the values of the spectroscopic factors obtained with the DWIA may increase by a few percent due to correlation effects in the final state.Comment: 21 Pages, PHY-7849-TH-9