53,269 research outputs found
Odontoameloblastoma with extensive chondroid matrix deposition in a guinea pig
Odontoameloblastomas (previously incorporated within ameloblastic odontomas) are matrix-producing odontogenic mixed tumors and are closely related in histologic appearance to the 2 other types of matrix-producing odontogenic mixed tumors: odontomas and ameloblastic fibro-odontomas. The presence or absence of intralesional, induced non-neoplastic tissue must be accounted for in the diagnosis. Herein we describe a naturally occurring odontoameloblastoma with extensive chondroid cementum deposition in a guinea pig (Cavia porcellus). Microscopically, the mass featured palisading neoplastic odontogenic epithelium closely apposed to ribbons and rings of a pink dental matrix (dentinoid), alongside extensive sheets and aggregates of chondroid cementum. The final diagnosis was an odontoameloblastoma given the abundance of odontogenic epithelium in association with dentinoid but a paucity of pulp ectomesenchyme. Chondroid cementum is an expected anatomical feature of cavies, and its presence within the odontoameloblastoma was interpreted as a response of the ectomesenchyme of the dental follicle to the described neoplasm. Our case illustrates the inductive capabilities of odontoameloblastomas while highlighting species-specific anatomy that has resulted in a histologic appearance unique to cavies and provides imaging and histologic data to aid diagnosis of these challenging lesions
Ultrahigh Transmission Optical Nanofibers
We present a procedure for reproducibly fabricating ultrahigh transmission
optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode
transmissions of 99.95 0.02%, which represents a loss from tapering of
2.6 10 dB/mm when normalized to the entire stretch. When
controllably launching the next family of higher-order modes on a fiber with
195 mm stretch, we achieve a transmission of 97.8 2.8%, which has a loss
from tapering of 5.0 10 dB/mm when normalized to the
entire stretch. Our pulling and transfer procedures allow us to fabricate
optical nanofibers that transmit more than 400 mW in high vacuum conditions.
These results, published as parameters in our previous work, present an
improvement of two orders of magnitude less loss for the fundamental mode and
an increase in transmission of more than 300% for higher-order modes, when
following the protocols detailed in this paper. We extract from the
transmission during the pull, the only reported spectrogram of a fundamental
mode launch that does not include excitation to asymmetric modes; in stark
contrast to a pull in which our cleaning protocol is not followed. These
results depend critically on the pre-pull cleanliness and when properly
following our pulling protocols are in excellent agreement with simulations.Comment: 32 pages, 10 figures, accepted to AIP Advance
Review of finite fields: Applications to discrete Fourier, transforms and Reed-Solomon coding
An attempt is made to provide a step-by-step approach to the subject of finite fields. Rigorous proofs and highly theoretical materials are avoided. The simple concepts of groups, rings, and fields are discussed and developed more or less heuristically. Examples are used liberally to illustrate the meaning of definitions and theories. Applications include discrete Fourier transforms and Reed-Solomon coding
Photon pair generation using four-wave mixing in a microstructured fibre: theory versus experiment
We develop a theoretical analysis of four-wave mixing used to generate photon
pairs useful for quantum information processing. The analysis applies to a
single mode microstructured fibre pumped by an ultra-short coherent pulse in
the normal dispersion region. Given the values of the optical propagation
constant inside the fibre, we can estimate the created number of photon pairs
per pulse, their central wavelength and their respective bandwidth. We use the
experimental results from a picosecond source of correlated photon pairs using
a micro-structured fibre to validate the model. The fibre is pumped in the
normal dispersion regime at 708nm and phase matching is satisfied for widely
spaced parametric wavelengths of 586nm and 894nm. We measure the number of
photons per pulse using a loss-independent coincidence scheme and compare the
results with the theoretical expectation. We show a good agreement between the
theoretical expectations and the experimental results for various fibre lengths
and pump powers.Comment: 23 pages, 9 figure
Azimuthal Asymmetry of Direct Photons in High Energy Nuclear Collisions
We show that a sizeable azimuthal asymmetry, characterized by a coefficient
v_2, is to be expected for direct photons produced in non-central high energy
nuclear collisions. This signal is generated by photons radiated by jets
interacting with the surrounding hot plasma. The anisotropy is out of phase by
an angle with respect to that associated with the elliptic anisotropy
of hadrons, leading to negative values of v_2. Such an asymmetry, if observed,
could be a signature for the presence of a quark gluon plasma and would
establish the importance of jet-plasma interactions as a source of
electromagnetic radiation.Comment: New title. Final versio
High Order Finite Element Discretization of the Compressible Euler and Navier-Stokes Equations
We present a high order accurate streamline-upwind/Petrov-Galerkin (SUPG) algorithm for the solution of the compressible Euler and Navier-Stokes equations. The flow equations are written in terms of entropy variables which result in symmetric flux Jacobian matrices and a dimensionally consistent Finite Element discretization. We show that solutions derived from quadratic element approximation are of superior quality next to their linear element counterparts. We demonstrate this through numerical solutions of both classical test cases as well as examples more practical in nature
Tripartite phase separation of two signal effectors with vesicles priming B cell responsiveness.
Antibody-mediated immune responses rely on antigen recognition by the B cell antigen receptor (BCR) and the proper engagement of its intracellular signal effector proteins. Src homology (SH) 2 domain-containing leukocyte protein of 65 kDa (SLP65) is the key scaffold protein mediating BCR signaling. In resting B cells, SLP65 colocalizes with Cbl-interacting protein of 85 kDa (CIN85) in cytoplasmic granules whose formation is not fully understood. Here we show that effective B cell activation requires tripartite phase separation of SLP65, CIN85, and lipid vesicles into droplets via vesicle binding of SLP65 and promiscuous interactions between nine SH3 domains of the trimeric CIN85 and the proline-rich motifs (PRMs) of SLP65. Vesicles are clustered and the dynamical structure of SLP65 persists in the droplet phase in vitro. Our results demonstrate that phase separation driven by concerted transient interactions between scaffold proteins and vesicles is a cellular mechanism to concentrate and organize signal transducers
Generation of the auroral kilometric radiation
For abstract, see A82-3554
Human engineering design criteria study Final report
Human engineering design criteria for use in designing earth launch vehicle systems and equipmen
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