159 research outputs found
Multiple D-branes as a D-brane
From BFSS matrix theory considerations, it is expected that a single
D-brane action can be obtained from N D-brane action in large N
limit. We examine and confirm this expectation by working out the details of
DBI and Chern-Simons terms of D-brane action from D-brane action.
We show that the same relation works for non-BPS, as well as BPS branesComment: 14 page
The interrelation between the generation of large-scale electric fields and that of large-scale magnetic fields during inflation
The interrelation between the generation of large-scale electric fields and
that of large-scale magnetic fields due to the breaking of the conformal
invariance of the electromagnetic field in inflationary cosmology is studied.
It is shown that if large-scale magnetic fields with a sufficiently large
amplitude are generated during inflation, the generation of large-scale
electric fields is suppressed, and vice versa. Furthermore, a physical
interpretation of the result and its cosmological significance are considered.Comment: 12 pages, no figure, title changed, typos correcte
Disulfide-induced self-assembled targets: A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles
A modified non-cross-linking gold-nanoparticles (Au-NPs) aggregation strategy has been developed for the label free colorimetric detection of DNAs/RNAs based on self-assembling target species in the presence of thiolated probes. Two complementary thiol- modified probes, each of which specifically binds at one half of the target introduced SH groups at both ends of dsDNA. Continuous disulfide bond formation at 3′ and 5′ terminals of targets leads to the self-assembly of dsDNAs into the sulfur- rich and flexible products with different lengths. These products have a high affinity for the surface of Au-NPs and efficiently protect the surface from salt induced aggregation. To evaluate the assay efficacy, a small part of the citrus tristeza virus (CTV) genome was targeted, leading to a detection limit of about 5 × 10-9 mol.L-1 over a linear ranged from 20 × 10-9 to 10 × 10-7 mol.L-1. This approach also exhibits good reproducibility and recovery levels in the presence of plant total RNA or human plasma total circulating RNA extracts. Self-assembled targets can be then sensitively distinguished from non-assembled or mismatched targets after gel electrophoresis. The disulfide reaction method and integrating self-assembled DNAs/RNAs targets with bare AuNPs as a sensitive indicator provide us a powerful and simple visual detection tool for a wide range of applications
Large-scale magnetic fields from inflation due to Chern-Simons-like effective interaction
We discuss the generation of large-scale magnetic fields due to the breaking
of the conformal invariance in the electromagnetic field through the -even
dimension-six Chern-Simons-like effective interaction with a fermion current in
inflationary cosmology. It is shown that the magnetic fields on 1Mpc scale with
the field strength of G at the present time can be generated even
for the scale of the effective interaction being the Planck scale.Comment: 13 pages, 2 figures, additional explanations include
The effect of trehalose administration on vascular inflammation in patients with coronary artery disease
Nambu-Poisson Bracket and M-Theory Branes Coupled to Antisymmetric Fluxes
By using the recently proposed prescription arXiv:0804.3629 for obtaining the
brane action from multiple branes action in BLG theory, we examine
such transition when 11 Dimensional background antisymmetric fluxes couple to
the brane world volume. Such couplings was suggested in arXiv:0805.3427
where it was used the fact that various fields in BLG theory are valued in a
Lie 3-algebra. We argue that this action and promoting it by Nambu-Poisson
bracket gives the expected coupling of fluxes with brane at least at weak
coupling limit. We also study some other aspects of the action for example, the
gauge invariance of the theory.Comment: 14 page
The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent
A Quintessentially Geometric Model
We consider string inspired cosmology on a solitary -brane moving in the
background of a ring of branes located on a circle of radius . The motion of
the -brane transverse to the plane of the ring gives rise to a radion field
which can be mapped to a massive non-BPS Born-Infeld type field with a cosh
potential. For certain bounds of the brane tension we find an inflationary
phase is possible, with the string scale relatively close to the Planck scale.
The relevant perturbations and spectral indices are all well within the
expected observational bounds. The evolution of the universe eventually comes
to be dominated by dark energy, which we show is a late time attractor of the
model. However we also find that the equation of state is time dependent, and
will lead to late time Quintessence.Comment: 11 pages, 3 figures. References and comments adde
Janus Field Theories from Non-Linear BF Theories for Multiple M2-Branes
We integrate the nonpropagating B_{\mu} gauge field for the non-linear BF
Lagrangian describing N M2-branes which includes terms with even number of the
totally antisymmetric tensor M^{IJK} in arXiv:0808.2473 and for the two-types
of non-linear BF Lagrangians which include terms with odd number of M^{IJK} as
well in arXiv:0809:0985. For the former Lagrangian we derive directly the
DBI-type Lagrangian expressed by the SU(N) dynamical A_{\mu} gauge field with a
spacetime dependent coupling constant, while for the low-energy expansions of
the latter Lagrangians the B_{\mu} integration is iteratively performed. The
derived Janus field theory Lagrangians are compared.Comment: 16 pages, LaTex, no figure
On Effective Potential in Tortoise Coordinate
In this paper, we study the field dynamics in Tortoise coordinate where the
equation of motion of a scalar can be written as Schrodinger-like form. We
obtain a general form for effective potential by finding the Schrodinger
equation for scalar and spinor fields and study its global behavior in some
black hole backgrounds in three dimension such as BTZ black holes, new type
black holes and black holes with no horizon.
Especially, we study the asymptotic behavior of potential at infinity,
horizons and origin and find that its asymptotic in BTZ and new type solution
is completely different from that of vanishing horizon solution. In fact,
potential for vanishing horizon goes to a fixed quantity at infinity, while in
BTZ and new type black hole we have an infinite barrier.Comment: 18 pages, 9 figure
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