1,563 research outputs found
Prostaglandin E2 Adds Bone to a Cancellous Bone Site with a Closed Growth Plate and Low Bone Turnover in Ovariectomized Rats
The objects of this study were to determine the responses of a cancellous bone site with a closed growth plate, (the distal tibial metaphysis (DTM), to ovariectomy (OVX) and OVX plus a prostaglandin E(2) treatment, and compare the site's response to previous findings reported for another site, the proximal tibial metaphysis (PTM). Thirty five 3-month old female Sprague-Dawley rats were divided into five groups; basal, sham OVX, and OVX+0, +1, or +6 mg PGE(2)/kg/d injected subcutaneously for 3 months and given double fluorescent labels before sacrifice. Cancellous bone histomorphometric analyses were performed on 20 micrometer thick undecalcified DTM sections. Similar to the PTM, the DTM showed age-related decreases in bone formation and increases in bone resorption, but it differed in that at 3 months POST OVX there was neither bone loss nor changes in formation endpoints. Giving 1 mg PGE(2)/kg/d to OVX rats prevented most age-related changes and maintained the bone formation histomorphometry near basal levels. Treating OVX rats with 6 mg PGE(2)/kd/d prevented age-related bone changes, added extra bone, and improved microanatomical structure by stimulating bone formation, without altering bone resportion. Futhermore, After PGE(2) admimnistration, the DTM, a cancellous bone site with a closed growth plate, increased bone formation more than did the cancellous bone in the PTM
Remineralization of demineralized dentin using a dual analog system.
ObjectiveImproved methods are needed to remineralize dentin caries in order to promote conservation of dentin tissue and minimize the surgical interventions that are currently required for clinical treatment. Here, we test the hypothesis that bulk substrates can be effectively mineralized via a dual analog system proposed by others, using a tripolyphosphate (TPP) "templating analog" and a poly(acrylic acid) (PAA) or poly(aspartic acid) (pAsp) "sequestration analog," the latter of which generates the polymer-induced liquid-precursor (PILP) mineralization process studied in our laboratory.Material & methodsDemineralized human dentin slices were remineralized with and without pre-treatment with TPP, using either PAA or pAsp as the PILP process-directing agent. A control experiment with no polymer present was used for comparison.ResultsNo mineralization was observed in any of the PAA groups. In both the pAsp and no polymer groups, TPP inhibited mineralization on the surfaces of the specimens but promoted mineralization within the interiors. Pre-treatment with TPP enhanced overall mineralization of the pAsp group. However, when analysed via TEM, regions with little mineral were still present.ConclusionPoly(acrylic acid) was unable to remineralize demineralized dentin slices under the conditions employed, even when pre-treated with TPP. However, pre-treatment with TPP enhanced overall mineralization of specimens that were PILP-remineralized using pAsp
Oral health and later coronary heart disease: Cohort study of one million people
AIMS:
Systematic reviews report an association between poorer oral health and an increased risk of coronary heart disease. This contentious relationship may not be causal but existing studies have been insufficiently well powered comprehensively to examine the role of confounding, particularly by cigarette smoking. Accordingly, we sought to examine the role of smoking in generating the relationship between oral health and coronary heart disease in life-long non-smokers.
METHODS AND RESULTS:
In the Korean Cancer Prevention Study, 975,685 individuals (349,579 women) aged 30â95 years had an oral examination when tooth loss, a widely used indicator of oral health, was ascertained. Linkage to national mortality and hospital registers over 21 years of follow-up gave rise to 64,784 coronary heart disease events (19,502 in women). In the whole cohort, after statistical adjustment for age, there was a moderate, positive association between tooth loss and coronary heart disease in both men (hazard ratio for seven or more missing teeth vs. none; 95% confidence interval 1.08; 1.02, 1.14; Ptrend across tooth loss groups <0.0001) and women (1.09; 1.01, 1.18; Ptrend 0.0016). Restricting analyses to a subgroup of 464,145 never smokers (25,765 coronary heart disease events), however, resulted in an elimination of this association in men (1.01; 0.85, 1.19); Ptrend 0.7506) but not women (1.08; 0.99, 1.18; Ptrend 0.0086).
CONCLUSION: In men in the present study, the relationship between poor oral health and coronary heart disease risk appeared to be explained by confounding by cigarette smoking so raising questions about a causal link
Additive noise properties of active matrix flatĂą panel imagers
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134764/1/mp6721.pd
GALEX UV Color-Magnitude Relations and Evidence for Recent Star Formation in Early-type Galaxies
We have used the GALEX UV photometric data to construct a first
near-ultraviolet (NUV) color-magnitude relation (CMR) for the galaxies
pre-classified as early-type by SDSS studies. The NUV CMR is a powerful tool
for tracking the recent star formation history in early-type galaxies, owing to
its high sensitivity to the presence of young stellar populations. Our NUV CMR
for UV-weak galaxies shows a well-defined slope and thus will be useful for
interpreting the restframe NUV data of distant galaxies and studying their star
formation history. Compared to optical CMRs, the NUV CMR shows a substantially
larger scatter, which we interpret as evidence of recent star formation
activities. Roughly 15% of the recent epoch (z < 0.13) bright (M[r] < -22)
early-type galaxies show a sign of recent (< 1Gyr) star formation at the 1-2%
level (lower limit) in mass compared to the total stellar mass. This implies
that low level residual star formation was common during the last few billion
years even in bright early-type galaxies.Comment: This paper will be published as part of the Galaxy Evolution Explorer
(GALEX) Astrophysical Journal Letters Special Issue. Links to the full set of
papers will be available at http://www.galex.caltech.edu/PUBLICATIONS/ after
November 22, 200
Spurious Shear in Weak Lensing with LSST
The complete 10-year survey from the Large Synoptic Survey Telescope (LSST)
will image 20,000 square degrees of sky in six filter bands every few
nights, bringing the final survey depth to , with over 4 billion
well measured galaxies. To take full advantage of this unprecedented
statistical power, the systematic errors associated with weak lensing
measurements need to be controlled to a level similar to the statistical
errors.
This work is the first attempt to quantitatively estimate the absolute level
and statistical properties of the systematic errors on weak lensing shear
measurements due to the most important physical effects in the LSST system via
high fidelity ray-tracing simulations. We identify and isolate the different
sources of algorithm-independent, \textit{additive} systematic errors on shear
measurements for LSST and predict their impact on the final cosmic shear
measurements using conventional weak lensing analysis techniques. We find that
the main source of the errors comes from an inability to adequately
characterise the atmospheric point spread function (PSF) due to its high
frequency spatial variation on angular scales smaller than in the
single short exposures, which propagates into a spurious shear correlation
function at the -- level on these scales. With the large
multi-epoch dataset that will be acquired by LSST, the stochastic errors
average out, bringing the final spurious shear correlation function to a level
very close to the statistical errors. Our results imply that the cosmological
constraints from LSST will not be severely limited by these
algorithm-independent, additive systematic effects.Comment: 22 pages, 12 figures, accepted by MNRA
The potato rhizosphere microbiota correlated to the yield of three different regions in Korea
We examined potato rhizosphere bacterial and fungal communities across three regions: Cheongju, Pyeongchang, and Gangneung. These regions have varying soil and climate conditions, resulting in different yields. We found that precipitation was the main limiting factor in our study while soil physiochemical factors affect bacterial and fungal microbiota in correlation with yield. Both bacterial and fungal microbiota showed distinct patterns according to the regions. ASVs positively correlated with yield were predominantly found in the Pyeongchang region which also produced the highest yields, while ASVs negatively correlated with yield were associated with Gangneung where the lowest yields were observed. The greatest bacterial and fungal diversity was detected in Pyeongchang consisting of Propionibacteriales, Burkholderiales, and Vicinamibacteriales. Gangneung, on the other hand primarily belong to Sordariales, Mortierellales, Cystofilobasidiales, and Tremellales. The putative yield-negative ASVs detected in Gangneung may have been influenced by drought stress. This work has highlighted key bacterial and fungal taxa as well as core taxa that may potentially be associated with high and low yields of potato in relation to metadata which includes soil chemical and physical parameters as well as weather data. Taken together we suggest that this information can be used to assess site suitability for potato production
Effects of La substitution on superconducting state of CeCoIn5
We report effects of La substitution on superconducting state of heavy
fermion superconductor CeCoIn5, as seen in transport and magnetization
measurements. As opposed to the case of conventional superconductors, pair
breaking by nonmagnetic La results in depression of Tc and indicates strong gap
anisotropy. Upper critical field Hc2 values decrease with increased La
concentration, but the critical field anisotropy, gamma=Hc2(a)/Hc2(c), does not
change in the Ce_{1-x}La_xCoIn5 (x=0-0.15). The electronic system is in the
clean limit for all values of x.Comment: Submitted to Phys. Rev.
The Hubble Space Telescope Cluster Supernova Survey: V. Improving the Dark Energy Constraints Above z>1 and Building an Early-Type-Hosted Supernova Sample
We present ACS, NICMOS, and Keck AO-assisted photometry of 20 Type Ia
supernovae SNe Ia from the HST Cluster Supernova Survey. The SNe Ia were
discovered over the redshift interval 0.623 < z < 1.415. Fourteen of these SNe
Ia pass our strict selection cuts and are used in combination with the world's
sample of SNe Ia to derive the best current constraints on dark energy. Ten of
our new SNe Ia are beyond redshift , thereby nearly doubling the
statistical weight of HST-discovered SNe Ia beyond this redshift. Our detailed
analysis corrects for the recently identified correlation between SN Ia
luminosity and host galaxy mass and corrects the NICMOS zeropoint at the count
rates appropriate for very distant SNe Ia. Adding these supernovae improves the
best combined constraint on the dark energy density \rho_{DE}(z) at redshifts
1.0 < z < 1.6 by 18% (including systematic errors). For a LambdaCDM universe,
we find \Omega_\Lambda = 0.724 +0.015/-0.016 (68% CL including systematic
errors). For a flat wCDM model, we measure a constant dark energy
equation-of-state parameter w = -0.985 +0.071/-0.077 (68% CL). Curvature is
constrained to ~0.7% in the owCDM model and to ~2% in a model in which dark
energy is allowed to vary with parameters w_0 and w_a. Tightening further the
constraints on the time evolution of dark energy will require several
improvements, including high-quality multi-passband photometry of a sample of
several dozen z>1 SNe Ia. We describe how such a sample could be efficiently
obtained by targeting cluster fields with WFC3 on HST.Comment: 27 pages, 11 figures. Submitted to ApJ. This first posting includes
updates in response to comments from the referee. See
http://www.supernova.lbl.gov for other papers in the series pertaining to the
HST Cluster SN Survey. The updated supernova Union2.1 compilation of 580 SNe
is available at http://supernova.lbl.gov/Unio
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