1,731 research outputs found
Watery-whiteness of market eggs
It was found impossible to measure the viscosity of thick egg albumen by the methods employed. Thin albumen, however, was found to be just as viscous in watery-white eggs as in those of first quality. The defect appears to be confined to the apparent thick albumen only. Watery-white eggs kept almost as well as first quality over a 14-day period. The differences were not large enough to warrant the inclusion of watery-white eggs with second-quality eggs, whose keeping quality was very poor. No evidence of bacterial infection was found in the watery-white eggs, and efforts to transfer the defect to normal eggs using the water-white albumen as inoculum were unsuccessful
No anomalous scaling in electrostatic calibrations for Casimir force measurements
In a recent paper (Phys.Rev.A78, 020101(R) (2008)), Kim at al. have reported
a large anomaly in the scaling law of the electrostatic interaction between a
sphere and a plate, which was observed during the calibration of their Casimir
force set-up. Here we experimentally demonstrate that in proper electrostatic
calibrations the scaling law follows the behavior expected from elementary
electrostatic arguments, even when the electrostatic voltage that one must
apply to minimize the force (typically ascribed to contact potentials) depends
on the separation between the surfaces.Comment: Final versio
Melting temperature of screened Wigner crystal on helium films by molecular dynamics
Using molecular dynamics (MD) simulation, we have calculated the melting
temperature of two-dimensional electron systems on \AA-\AA helium
films supported by substrates of dielectric constants
at areal densities varying from cm to cm. Our results are in good agreement with the available
theoretical and experimental results.Comment: 4 pages and 4 figure
TAG1 regulates the endocytic trafficking and signaling of the semaphorin3A receptor complex.
Endocytic trafficking of membrane proteins is essential for neuronal structure and function. We show that Transient Axonal Glycoprotein 1 (TAG1 or CNTN2), a contactin-related adhesion molecule, plays a central role in the differential trafficking of components of the semaphorin3A (Sema3A) receptor complex into distinct endosomal compartments in murine spinal sensory neuron growth cones. The semaphorin3A receptor is composed of Neuropilin1 (NRP1), PlexinA4, and L1, with NRP1 being the ligand-binding component. TAG1 interacts with NRP1, causing a change in its association with L1 in the Sema3A response such that L1 is lost from the complex following Sema3A binding. Initially, however, L1 and NRP1 endocytose together and only become separated intracellularly, with NRP1 becoming associated with endosomes enriched in lipid rafts and colocalizing with TAG1 and PlexinA4. When TAG1 is missing, NRP1 and L1 fail to separate and NRP1 does not become raft associated; colocalization with PlexinA4 is reduced and Plexin signaling is not initiated. These observations identify a novel role for TAG1 in modulating the intracellular sorting of signaling receptor complexes
Fully Analyzing an Algebraic Polya Urn Model
This paper introduces and analyzes a particular class of Polya urns: balls
are of two colors, can only be added (the urns are said to be additive) and at
every step the same constant number of balls is added, thus only the color
compositions varies (the urns are said to be balanced). These properties make
this class of urns ideally suited for analysis from an "analytic combinatorics"
point-of-view, following in the footsteps of Flajolet-Dumas-Puyhaubert, 2006.
Through an algebraic generating function to which we apply a multiple
coalescing saddle-point method, we are able to give precise asymptotic results
for the probability distribution of the composition of the urn, as well as
local limit law and large deviation bounds.Comment: LATIN 2012, Arequipa : Peru (2012
Fiber-diffraction Interferometer using Coherent Fiber Optic Taper
We present a fiber-diffraction interferometer using a coherent fiber optic
taper for optical testing in an uncontrolled environment. We use a coherent
fiber optic taper and a single-mode fiber having thermally-expanded core. Part
of the measurement wave coming from a test target is condensed through a fiber
optic taper and spatially filtered from a single-mode fiber to be reference
wave. Vibration of the cavity between the target and the interferometer probe
is common to both reference and measurement waves, thus the interference fringe
is stabilized in an optical way. Generation of the reference wave is stable
even with the target movement. Focus shift of the input measurement wave is
desensitized by a coherent fiber optic taper
Recursive solutions for Laplacian spectra and eigenvectors of a class of growing treelike networks
The complete knowledge of Laplacian eigenvalues and eigenvectors of complex
networks plays an outstanding role in understanding various dynamical processes
running on them; however, determining analytically Laplacian eigenvalues and
eigenvectors is a theoretical challenge. In this paper, we study the Laplacian
spectra and their corresponding eigenvectors of a class of deterministically
growing treelike networks. The two interesting quantities are determined
through the recurrence relations derived from the structure of the networks.
Beginning from the rigorous relations one can obtain the complete eigenvalues
and eigenvectors for the networks of arbitrary size. The analytical method
opens the way to analytically compute the eigenvalues and eigenvectors of some
other deterministic networks, making it possible to accurately calculate their
spectral characteristics.Comment: Definitive version accepted for publication in Physical Reivew
Endocytosis Occurs Independently Of Annexin-Vi In Human A431 Cells
Annexin VI is one of a family of calcium-dependent phospholipid-binding proteins. Although the function of this protein is not known, various physiological roles have been proposed, including a role in the budding of clathrin-coated pits (Lin et al., 1992. Cell. 70:283-291.). In this study we have investigated a possible endocytotic role for annexin VI in intact cells, using the human squamous carcinoma cell line A431, and report that these cells do not express endogenous annexin VI, as judged by Western and Northern blotting and PCR/Southern blotting. To examine whether endocytosis might in some way be either facilitated or inhibited by the presence of annexin VI, a series of A431 clones were isolated in which annexin VI expression was achieved by stable transfection. These cells expressed annexin VI at similar levels to other human cell types. Using assays for endocytosis and recycling of the transferrin receptor, we report that each of these cellular processes occurs with identical kinetics in both transfected and wild-type A431 cells. In addition, purified annexin VI failed to support the scission of coated pits in permeabilized A431 cells. We conclude that annexin VI is not an essential component of the endocytic pathway, and that in A431 cells, annexin VI fails to exert any influence on internalization and recycling of the transferrin receptor
Interaction of vortices in thin superconducting films and Berezinskii-Kosterlitz-Thouless transition
The precondition for the BKT transition in thin superconducting films, the
logarithmic intervortex interaction, is satisfied at distances short relative
to , is the London penetration depth of the
bulk material and is the film thickness. For this reason, the search for
the transition has been conducted in samples of the size . It is
argued below that film edges turn the interaction into near exponential
(short-range) thus making the BKT transition impossible. If however the
substrate is superconducting and separated from the film by an insulated layer,
the logarithmic intervortex interaction is recovered and the BKT transition
should be observable.Comment: 4 pages, no figure
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