861 research outputs found
INTERACTIONS OF HUMAN ORAL CELLS WITH ORAL BACTERIAL
poster abstractIntroduction: Streptococcus mutans is the main etiological cause of den-tal caries, and it has been shown that individuals who smoke have increased dental caries. S. mutans is known to bind to or interact with MG63 osteo-blasts. However, very little is known about the effects of tobacco directly on these bacteria on their ability to affect human pulp MG63 osteoblasts. We are hypothesizing that tobacco upregulates the expression of pro-inflammatory cytokines and MMPs to increase the pathogenic potential of S. mutans. The objective of this research project is to investigate the effects that nicotine, cigarette smoke condensate (CSC), and dissolvable smokeless tobacco (DST)-extract treated bacterial cells have on humanMG63 osteo-blasts, in respect to their release of pro-inflammatory and anti-inflammatory cytokines, as well as MMP expression. In addition, the effects of the S. mutans cells will be examined for the ability to affect MG63 osteoblast growth. The long-term goal is to develop treatment modalities to reduce the effects of smoking on dental caries.
Materials and Methods: S. mutans UA159 was incubated in Tryptic Soy Broth (TSB), with the following concentrations: 2 mg/mL nicotine, 0.125 mg/mL CSC, 100 uL/3 mL DST-extract, and a 0 mg/mL control group. The cultures were grown in the presence of the tobacco products for 8 h at 37oC in 5% CO2, and centrifuged to isolate cells and supernatants. The cells were washed and heat-killed for 1 h at 60oC. Human MG63 osteoblasts were iso-lated from extracted teeth, and cell passages 3-8 will be used. The tobacco-treated S. mutans cells and supernatants will be incubated with the osteo-blasts in culture plates for 72 h and cytokine expression evaluated by re-verse transcriptase polymerase chain reaction.
Results: The protein concentration of each tobacco-treated sample was found. The undiluted concentrations of the nicotine- and CSC-treated cells were slightly lower and the DST-treated cells was slightly higher than the control cells. The undiluted nicotine (p<0.05) and DST-treated supernatants were higher than the control, while the CSC supernatant protein concentra-tion was lower. From our previous studies, it was found that nicotine in-creases bacteriocin production of S. mutans, so we might hypothesize that nicotine induces bacteriocin secretion, thus increasing dental caries
Estimating Watershed Evapotranspiration with PASS. Part I: Inferring Root-Zone Moisture Conditions Using Satellite Dat
A model framework for parameterized subgrid-scale surface fluxes (PASS) has been modified and applied as
PASS1 to use satellite data, models, and limited surface observations to infer root-zone available moisture (RAM)
content with high spatial resolution over large terrestrial areas. Data collected during the 1997 Cooperative
Atmosphere–Surface Exchange Study field campaign at the Atmospheric Boundary Layer Experiments site in
the Walnut River watershed in Kansas were used to evaluate applications of the PASS1 approach to infer soil
moisture content at times of satellite overpasses during cloudless conditions. Data from Advanced Very High
Resolution Radiometers on the NOAA-14 satellite were collected and then adjusted for atmospheric effects by
using LOWTRAN7 and local atmospheric profile data from radiosondes. The input variables for PASS1 consisted
of normalized difference vegetation index and surface radiant temperature, together with representative observations
of downwelling solar irradiance, air temperature, relative humidity, and wind speed. Surface parameters,
including roughness length, albedo, surface conductance for water vapor, and the ratio of soil heat flux to net
radiation, were estimated with parameterizations suitable for the area using satellite data and land-use information;
pixel-specific near-surface meteorological conditions such as air temperature, vapor pressure, and wind speed
were adjusted according to local surface forcing; and RAM content was estimated using surface energy balance
and aerodynamic methods. Comparisons with radar cumulative precipitation observations and in situ soil moisture
estimates indicated that the spatial and temporal variations of RAM at the times of satellite overpasses were
simulated reasonably well by PASS1
Wettability influences cell behavior on superhydrophobic surfaces with different topographies
Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of polystyrene and poly(l-lactic acid) with different micro/nanotopographies were obtained from smooth surfaces using a simple phase-separation based method. Total protein was quantified and showed a less adsorption of bovine serum albumin onto rough surfaces as compared to smooth surfaces of the same material. The mouse osteoblastic MC3T3-E1 cell line and primary bovine articular chondrocytes were used to study cell attachment and proliferation. Cells attached and proliferate better in the smooth surfaces. The superhydrophobic surfaces allowed cells to adhere but inhibited their proliferation. This study indicates that surface wettability, rather than polymer type or the topography of the superhydrophobic surfaces, is a critical factor in determining cell behavior
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Feasibility studies of a compact mm-wave linac FEL
Short wavelength FELs impose stringent requirements on the quality of the electron beams. The key factor in obtaining a single-pass UV or x-ray FEL is the generation of small emittance electron beams with ultra-high brightness. The pioneering work at Los Alamos National Laboratory in the last decade has resulted in a dramatic improvement in the production of high electron beam brightness and small beam emittance using rf photocathode gun. The lower bound on the emittance of a 1-nC bunch without any emittance compensation is on the order of 3 {pi} mm-mrad. This is well within the emittance requirement being considered here. Although the original R&D work at Argonne, in collaboration with the University of Illinois at Chicago and University of Wisconsin-Madison, has produced encouraging results in the area of rf structure design, x-ray mask fabrication, and LIGA processing (Lithography, Electroforming, and Molding), the goal to prove feasibility has not yet been achieved. In this paper, we will present feasibility studies for a compact single-pass mm-linac FEL based on LIGA technology. This system will consist of a photocathode rf gun operated at 30 GHz, a 50-MeV superconducting constant gradient structure operated at 60 GHz, and a microundulator with 1-mm period
Pion propagation in real time field theory at finite temperature
We describe how the thermal counterpart of a vacuum two-point function may be
obtained in the real time formalism in a simple way by using directly the
matrices that different elements acquire in this formalism. Using
this procedure we calculate the analytic (single component) thermal amplitude
for the pion pole term in the ensemble average of two axial-vector currents to
two loops in chiral perturbation theory. The general expressions obtained for
the effective mass and decay constants of the pion are evaluated in the chiral
and the nonrelativistic limits. We also investigate the effect of massive
states on these effective parameters.Comment: 17 pages TeX and 9 eps figure
Hopping motion of lattice gases through nonsymmetric potentials under strong bias conditions
The hopping motion of lattice gases through potentials without
mirror-reflection symmetry is investigated under various bias conditions. The
model of 2 particles on a ring with 4 sites is solved explicitly; the resulting
current in a sawtooth potential is discussed. The current of lattice gases in
extended systems consisting of periodic repetitions of segments with sawtooth
potentials is studied for different concentrations and values of the bias.
Rectification effects are observed, similar to the single-particle case. A
mean-field approximation for the current in the case of strong bias acting
against the highest barriers in the system is made and compared with numerical
simulations. The particle-vacancy symmetry of the model is discussed.Comment: 8 pages (incl. 6 eps figures); RevTeX 3.
Schroedinger cat-like states by conditional measurements on a beam-splitter
A scheme for generating Schr\"{o}dinger cat-like states of a single-mode
optical field by means of conditional measurement is proposed. Feeding into a
beam splitter a squeezed vacuum and counting the photons in one of the output
channels, the conditional states in the other output channel exhibit a number
of properties that are very similar to those of superpositions of two coherent
states with opposite phases. We present analytical and numerical results for
the photon-number and quadrature-component distributions of the conditional
states and their Wigner and Husimi functions. Further, we discuss the effect of
realistic photocounting on the states.Comment: 6 figures(divided in subfigures) using a4.st
Skyrmion Excitations in Quantum Hall Systems
Using finite size calculations on the surface of a sphere we study the
topological (skyrmion) excitation in quantum Hall system with spin degree of
freedom at filling factors around . In the absence of Zeeman energy, we
find, in systems with one quasi-particle or one quasi-hole, the lowest energy
band consists of states with , where and are the total orbital and
spin angular momentum. These different spin states are almost degenerate in the
thermodynamic limit and their symmetry-breaking ground state is the state with
one skyrmion of infinite size. In the presence of Zeeman energy, the skyrmion
size is determined by the interplay of the Zeeman energy and electron-electron
interaction and the skyrmion shrinks to a spin texture of finite size. We have
calculated the energy gap of the system at infinite wave vector limit as a
function of the Zeeman energy and find there are kinks in the energy gap
associated with the shrinking of the size of the skyrmion. breaking ground
state is the state with one skyrmion of infinite size. In the presence of
Zeeman energy, the skyrmion size is determined by the interplay of the Zeeman
energy and electron-electronComment: 4 pages, 5 postscript figures available upon reques
A non-parametric structural hybrid modeling approach for electricity prices
We develop a stochastic model of zonal/regional electricity prices, designed to reflect information in fuel forward curves and aggregated capacity and load as well as zonal or regional price spreads. We use a nonparametric model of the supply stack that captures heat rates and fuel prices for all generators in the market operator territory, combined with an adjustment term to approximate congestion and other zone-specific behavior. The approach requires minimal calibration effort, is readily adaptable to changing market conditions and regulations, and retains sufficient tractability for the purpose of forward price calibration. The model is illustrated for the spot and forward electricity prices of the PS zone in the PJM market, and the set of time-dependent risk premiums are inferred and analyzed
Signal and System Approximation from General Measurements
In this paper we analyze the behavior of system approximation processes for
stable linear time-invariant (LTI) systems and signals in the Paley-Wiener
space PW_\pi^1. We consider approximation processes, where the input signal is
not directly used to generate the system output, but instead a sequence of
numbers is used that is generated from the input signal by measurement
functionals. We consider classical sampling which corresponds to a pointwise
evaluation of the signal, as well as several more general measurement
functionals. We show that a stable system approximation is not possible for
pointwise sampling, because there exist signals and systems such that the
approximation process diverges. This remains true even with oversampling.
However, if more general measurement functionals are considered, a stable
approximation is possible if oversampling is used. Further, we show that
without oversampling we have divergence for a large class of practically
relevant measurement procedures.Comment: This paper will be published as part of the book "New Perspectives on
Approximation and Sampling Theory - Festschrift in honor of Paul Butzer's
85th birthday" in the Applied and Numerical Harmonic Analysis Series,
Birkhauser (Springer-Verlag). Parts of this work have been presented at the
IEEE International Conference on Acoustics, Speech, and Signal Processing
2014 (ICASSP 2014
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