135 research outputs found
Establishment of porcine pulp-derived cell lines and expression of recombinant dentin sialoprotein and recombinant dentin matrix protein-1
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72436/1/j.1600-0722.2007.00426.x.pd
Non-simply-laced Lie algebras via F theory strings
In order to describe the appearance in F theory of the non--simply--laced Lie
algebras, we use the representation of symmetry enhancements by means of string
junctions. After an introduction to the techniques used to describe symmetry
enhancement, that is algebraic geometry, BPS states analysis and string
junctions, we concentrate on the latter. We give an explicit description of the
folding of D_{2n} to B_n of the folding of E_6 to F_4 and that of D_4 to G_2 in
terms of junctions and Jordan strings. We also discuss the case of C_n, but we
are unable in this case to provide a string interpretation.Comment: 24 pages, 3 figure
Double-Lepton Polarization Asymmetries and Branching Ratio in B \rar K_{0}^{*}(1430) l^+ l^- transition from Universal Extra Dimension Model
We investigate the B \rar K_{0}^{*}(1430) l^+ l^- transition in the
Applequist-Cheng-Dobrescu model in the presence of a universal extra dimension.
In particular, we calculate double lepton polarization asymmetries and
branching ratio related to this channel and compare the obtained results with
the predictions of the standard model. Our analysis of the considered
observables in terms of radius of the compactified extra-dimension as the
new parameter of the model show a considerable discrepancy between the
predictions of two models in low values.Comment: 12 Pages, 15 Figures and 1 Tabl
Amelioration of bleomycin-induced lung fibrosis in hamsters by dietary supplementation with taurine and niacin: biochemical mechanisms.
Interstitial pulmonary fibrosis induced by intratracheal instillation of bleomycin (BL) involves an excess production of reactive oxygen species, unavailability of adequate levels of NAD and ATP to repair the injured pulmonary epithelium, and an overexuberant lung collagen reactivity followed by deposition of highly cross-linked mature collagen fibrils resistant to enzymatic degradation. In the present study, we have demonstrated that dietary supplementation with taurine and niacin offered almost complete protection against the lung fibrosis in a multidose BL hamster model. The mechanisms for the protective effect of taurine and niacin are multifaceted. These include the ability of taurine to scavenge HOCl and stabilize the biomembrane; niacin's ability to replenish the BL-induced depletion of NAD and ATP; and the combined effect of taurine and niacin to suppress all aspects of BL-induced increases in the lung collagen reactivity, a hallmark of interstitial pulmonary fibrosis. It was concluded from the data presented at this Conference that the combined treatment with taurine and niacin, which offers a multipronged approach, will have great therapeutic potential in the intervention of the development of chemically induced interstitial lung fibrosis in animals and humans
The sensitivity of the zero position of the forward--backward asymmetry to new physics effects in the B -> K^\ast \mu^+ \mu^- decay
Starting with the most general effective Hamiltonian comprising scalar and
vector operators beyond the standard model, we discuss the impact of various
operators on the zero of the forward--backward asymmetry in the dileptonic B
decay B -> K^\ast \mu^+ \mu^-. We find that, zero of the asymmetry is highly
sensitive to the sign and size of the vector--vector operators and opposite
chirality counterparts of the usual operators. The scalar--scalar four--fermion
operators, on the other hand, have mild effect on the zero of the asymmetry.
Our results are expected to be checked in the near future experiments.Comment: 16 pp, 6 ps fig
F-Theory and the Mordell-Weil Group of Elliptically-Fibered Calabi-Yau Threefolds
The Mordell-Weil group of an elliptically fibered Calabi-Yau threefold X
contains information about the abelian sector of the six-dimensional theory
obtained by compactifying F-theory on X. After examining features of the
abelian anomaly coefficient matrix and U(1) charge quantization conditions of
general F-theory vacua, we study Calabi-Yau threefolds with Mordell-Weil
rank-one as a first step towards understanding the features of the Mordell-Weil
group of threefolds in more detail. In particular, we generate an interesting
class of F-theory models with U(1) gauge symmetry that have matter with both
charges 1 and 2. The anomaly equations --- which relate the Neron-Tate height
of a section to intersection numbers between the section and fibral rational
curves of the manifold --- serve as an important tool in our analysis.Comment: 29 pages + appendices, 5 figures; v2: minor correction
Analysis of Neutral Higgs-Boson Contributions to the Decays B_s -> l^+l^- and B -> K l^+l^-
We report on a calculation of Higgs-boson contributions to the decays B_s ->
l^+l^- and B -> K l^+l^- (l=e, mu) which are governed by the effective
Hamiltonian describing b -> s l^+ l^-. Compact formulae for the Wilson
coefficients are provided in the context of the type-II two-Higgs-doublet model
(2HDM) and supersymmetry (SUSY) with minimal flavour violation, focusing on the
case of large tan(beta). We derive, in a model-independent way, constraints on
Higgs-boson-mediated interactions, using present experimental results on rare B
decays including b -> s gamma, B_s -> mu^+ mu^-, and B -> K^(*) mu^+ mu^-. In
particular, we assess the impact of possible scalar and pseudoscalar
interactions transcending the standard model (SM) on the branching ratio of B_s
-> mu^+ mu^- and the forward-backward (FB) asymmetry of mu^- in B -> K mu^+
mu^- decay. We find that the average FB asymmetry, which is unobservably small
within the SM, and therefore a potentially valuable tool to search for new
physics, is predicted to be no greater than 4% for a nominal branching ratio of
about 6x10^{-7}. Moreover, striking effects on the decay spectrum of B -> K
mu^+ mu^- are already ruled out by experimental data on the B_s -> mu^+ mu^-
branching fraction. In addition, we study the constraints on the parameter
space of the 2HDM and SUSY with minimal flavour violation. While the type-II
2HDM does not give any sizable contributions to the above decay modes, we find
that SUSY contributions obeying the constraint on b -> s gamma can affect
significantly the branching ratio of B_s -> mu^+ mu^-. We also comment on
previous calculations contained in the literature.Comment: 29 pages, REVTeX, 8 figures. Minor corrections in Eqs. (5.4), (5.11)
and (6.3) of the published versio
Anomaly Equations and Intersection Theory
Six-dimensional supergravity theories with N=(1,0) supersymmetry must satisfy
anomaly equations. These equations come from demanding the cancellation of
gravitational, gauge and mixed anomalies. The anomaly equations have
implications for the geometrical data of Calabi-Yau threefolds, since F-theory
compactified on an elliptically fibered Calabi-Yau threefold with a section
generates a consistent six-dimensional N=(1,0) supergravity theory. In this
paper, we show that the anomaly equations can be summarized by three
intersection theory identities. In the process we also identify the geometric
counterpart of the anomaly coefficients---in particular, those of the abelian
gauge groups---that govern the low-energy dynamics of the theory. We discuss
the results in the context of investigating string universality in six
dimensions.Comment: 29 pages + appendices, 8 figures; v2: minor corrections, references
added; v3: minor corrections, reference adde
More Model-Independent Analysis of b->s Processes
We study model-independently the implications of non-standard scalar and
pseudoscalar interactions for the decays b ->s gamma, b -> s g, b -> s l^+l^-
(l=e,mu) and B_s -> mu^+ mu^-. We find sizeable renormalization effects from
scalar and pseudoscalar four-quark operators in the radiative decays and at
O(alpha_s) in hadronic b decays. Constraints on the Wilson coefficients of an
extended operator basis are worked out. Further, the ratios R_H = BR(B -> H
mu^+ mu^-)/BR(B -> H e^+ e^-), for H=K^(*), X_s, and their correlations with
B_s -> mu^+ mu^- decay are investigated. We show that the Standard Model
prediction for these ratios defined with the same cut on the dilepton mass for
electron and muon modes, R_H= 1 + O(m^2_mu/m^2_b), has a much smaller
theoretical uncertainty (<1%) than the one for the individual branching
fractions. The present experimental limit R_K < 1.2 puts constraints on scalar
and pseudoscalar couplings, which are similar to the ones from current data on
BR(B_s -> mu^+ mu^-). We find that new physics corrections to R_{K*} and
R_{X_s} can reach 13% and 10%, respectively.Comment: 28 pages, 6 figures; Table 1 updated, two refs added (to appear in
PRD
Lepton polarization correlations in
In this work we will study the polarizations of both leptons () in the
decay channel . In the case of the dileptonic inclusive
decay , where apart from the polarization asymmetries
of single lepton , one can also observe the polarization asymmetries of
both leptons simultaneously. If this sort of measurement is possible then we
can have, apart from decay rate, FB asymmetry and the six single lepton
polarization asymmetries (three each for and ), nine more
double polarization asymmetries. This will give us a very useful tool in more
strict testing of SM and the physics beyond. We discuss the double polarization
asymmetries of leptons in the decay mode within
the SM and the Minimal Supersymmetric extensions of it.Comment: 21 pages, 21 figures; version to match paper to appear in PR
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