436 research outputs found
DEVELOPMENT AND IN-VITRO EVALUATION OF QUANTUM DOTS AS A CARRIER FOR DELIVERY OF 5-FLUOROURACIL
Objective: The present study was aimed to develop and evaluate quantum dots (QDs) as a carrier for delivery of 5-fluorouracil (5-FU).Methods: This research work includes a synthesis, characterization and in vitro study of 5-fluorouracil (5-FU) QDs. Zinc oxide QDs were synthesized, and the drug was loaded on them. These QDs were further coated with Eudragit E PO to achieve drug release only at the acidic pH range as well as to overcome release of drug in the formulation vehicle itself.Results: For 5-FU QDs optimized batch, yield (74±0.001 %), drug loading (85.58±0.08 %) and drug content (95±0.015%) were observed. FTIR spectroscopy revealed no any incompatibility between drug, polymer and metal SEM images shown drug loaded QDs with rough surface and Eudragit E PO coated QDs with smooth surface. The DSC curve of 5-FU exhibits peak at 286 °C corresponding to its melting point and Eudragit E PO coated QDs exhibit peak at 272 °C. This shifting of the endotherm suggested possible interaction of 5-FU and Eudragit E PO coated QDs. The diffractogram of pure drug showed multi-crystalline nature. However pure Eudragit E PO showed amorphous nature. Optimized QDs showed the crystalline nature of the drug. Mean particle size of optimized formulation batch was 201.92 nm and zeta potential was found+1.85 mV.Conclusion: An Optimized batch of QDs has the potential to utilize in future for imaging of cancer cells and targeting delivery of 5-FU.Â
Probing top charged-Higgs production using top polarization at the Large Hadron Collider
We study single top production in association with a charged Higgs in the
type II two Higgs doublet model at the Large Hadron Collider. The polarization
of the top, reflected in the angular distributions of its decay products, can
be a sensitive probe of new physics in its production. We present theoretically
expected polarizations of the top for top charged-Higgs production, which is
significantly different from that in the closely related process of t-W
production in the Standard Model. We then show that an azimuthal symmetry,
constructed from the decay lepton angular distribution in the laboratory frame,
is a sensitive probe of top polarization and can be used to constrain
parameters involved in top charged-Higgs production.Comment: 22 pages, 18 Figures, Discussions about backgrounds and NLO
corrections added, figures modified, references added, Version published in
JHE
On measurement of top polarization as a probe of production mechanisms at the LHC
In this note we demonstrate the use of top polarization in the study of resonances at the LHC, in the possible case where the dynamics implies
a non-zero top polarization. As a probe of top polarization we construct an
asymmetry in the decay-lepton azimuthal angle distribution (corresponding to
the sign of ) in the laboratory. The asymmetry is non-vanishing
even for a symmetric collider like the LHC, where a positive axis is not
uniquely defined. The angular distribution of the leptons has the advantage of
being a faithful top-spin analyzer, unaffected by possible anomalous
couplings, to linear order. We study, for purposes of demonstration, the case
of a as might exist in the little Higgs models. We identify kinematic cuts
which ensure that our asymmetry reflects the polarization in sign and
magnitude. We investigate possibilities at the LHC with two energy options:
TeV and TeV, as well as at the Tevatron. At the
LHC the model predicts net top quark polarization of the order of a few per
cent for GeV, being as high as for a smaller mass
of the of GeV and for the largest allowed coupling in the model, the
values being higher for the TeV option. These polarizations translate to a
deviation from the standard-model value of azimuthal asymmetry of up to about
() for () TeV LHC, whereas for the Tevatron, values as high as
are attained. For the TeV LHC with an integrated luminosity of 10
fb, these numbers translate into a sensitivity over a large
part of the range GeV.Comment: 28 page, LaTeX, requires JHEP style file, 12 figures. Typos corrected
and references adde
The Neutron Electric Dipole Moment and CP-violating Couplings in the Supersymmetric Standard Model without R-parity
We analyze the neutron electric dipole moment (EDM) in the Minimal
Supersymmetric Model with explicit R-parity violating terms. The leading
contribution to the EDM occurs at the 2-loop level and is dominated by the
chromoelectric dipole moments of quarks, assuming there is no tree-level
mixings between sleptons and Higgs bosons or between leptons and gauginos.
Based on the experimental constraint on the neutron EDM, we set limits on the
imaginary parts of complex couplings and
due to the virtual b-loop or tau-loop.Comment: final manuscript to appear in Phys. Rev. D, 15 pages, latex, 4
figures include
Partial Covering Arrays: Algorithms and Asymptotics
A covering array is an array with entries
in , for which every subarray contains each
-tuple of among its rows. Covering arrays find
application in interaction testing, including software and hardware testing,
advanced materials development, and biological systems. A central question is
to determine or bound , the minimum number of rows of
a . The well known bound
is not too far from being
asymptotically optimal. Sensible relaxations of the covering requirement arise
when (1) the set need only be contained among the rows
of at least of the subarrays and (2) the
rows of every subarray need only contain a (large) subset of . In this paper, using probabilistic methods, significant
improvements on the covering array upper bound are established for both
relaxations, and for the conjunction of the two. In each case, a randomized
algorithm constructs such arrays in expected polynomial time
Pattern Avoidance in Poset Permutations
We extend the concept of pattern avoidance in permutations on a totally
ordered set to pattern avoidance in permutations on partially ordered sets. The
number of permutations on that avoid the pattern is denoted
. We extend a proof of Simion and Schmidt to show that for any poset , and we exactly classify the posets for which
equality holds.Comment: 13 pages, 1 figure; v2: corrected typos; v3: corrected typos and
improved formatting; v4: to appear in Order; v5: corrected typos; v6: updated
author email addresse
High Precision and -production data and the Nuclear Glue
We use the high statistics E-772 data on the nuclear dependence of the
production of quarkonia and and dimuons at large
transverse momentum in - collisions to get information about the
gluonic EMC effect. We find a satisfactory quantitative agreement of the
theoretical predictions with the data although none of the models of the EMC
effect we consider could account for the entire data. Since all the qualitative
features are understood none the less in terms of perturbative QCD with nuclear
dependent parton densities, our results suggest that these data can now be used
for a better determination of the nuclear parton densities. Our conslusions are
shown to be insensitive to the hadronisation mechanism for the quarkonia.Comment: 28 pages, 8 Figures (included as uuencoded figs.uu file at the end),
RevTeX, TIFR/TH/93-57, BU-TH-93/
Flavor Alignment in SUSY GUTs
A Supersymmetric Grand unified model is constructed based on SO(10)xSO(10)
symmetry in which new types of Yukawa matrices couple standard and exotic
fermions. Evolution of these couplings from the Grand Unified scale to the
electroweak scale causes some of them to be driven to their fixed points. This
solves the supersymmetric alignment problem and ensures that there are no
observable flavor changing neutral currents mediated by supersymmetric
particles. Fermion hierarchy and neutrino mixing constraints are automatically
satisfied in this formalism.Comment: 20 pages, 1 figur
Forward Physics at the LHC (Elba 2010)
The papers review the main theoretical and experimental aspects of the
Forward Physics at the Large Hadron Collider
Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space
The scale factor , which characterizes double parton collisions
in high energy hadron interactions, is a direct manifestation of the
distribution of the interacting partons in transverse space, in such a way that
different distributions give rise to different values of in
different double parton collision processes. We work out the value of the scale
factor in a few reactions of interest, in a correlated model of the
multi-parton density of the proton recently proposed.Comment: 10 pages, 2 figure
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