2,934 research outputs found
Sugawara and vertex operator constructions for deformed Virasoro algebras
From the defining exchange relations of the A_{q,p}(gl_{N}) elliptic quantum
algebra, we construct subalgebras which can be characterized as q-deformed W_N
algebras. The consistency conditions relating the parameters p,q,N and the
central charge c are shown to be related to the singularity structure of the
functional coefficients defining the exchange relations of specific vertex
operators representations of A_{q,p}({gl_{N}) available when N=2.Comment: 23 page
The Integrals of Motion for the Deformed W-Algebra II: Proof of the commutation relations
We explicitly construct two classes of infinitly many commutative operators
in terms of the deformed W-algebra , and give proofs of the
commutation relations of these operators. We call one of them local integrals
of motion and the other nonlocal one, since they can be regarded as elliptic
deformation of local and nonlocal integrals of motion for the algebra.Comment: Dedicated to Professor Tetsuji Miwa on the occasion on the 60th
birthda
Graph-theory induced gravity and strongly-degenerate fermions in a self-consistent Einstein universe
We study UV-finite theory of induced gravity. We use scalar fields, Dirac
fields and vector fields as matter fields whose one-loop effects induce the
gravitational action. To obtain the mass spectrum which satisfies the
UV-finiteness condition, we use a graph-based construction of mass matrices.
The existence of a self-consistent static solution for an Einstein universe is
shown in the presence of degenerate fermion.Comment: 16pages, 1figur
Testing Parity Symmetry with the Polarized Cosmic Microwave Background
New physics in the early Universe could lead to parity-violation in the late
Universe, sourcing statistics whose sign changes under point reflection. The
best constraints on such phenomena have come from the Planck temperature
fluctuations; however, this is already cosmic-variance-limited down to
relatively small scales, thus only small improvements are expected in the
future. Here, we search for signatures of parity-violation in the polarized
CMB, using the Planck PR4 - and -mode data. We perform both a
simulation-based blind test for any parity-violating signal at , and
a targeted search for primordial gauge fields (and the amplitudes of a
generic collapsed model) at . In all cases, we find no evidence for
new physics, with the model-independent test finding consistency with the
FFP10/NPIPE simulation suite at , and the gauge field test
constraining the fractional amplitude of gauge fields during inflation to be
below at confidence level for a fiducial model. The
addition of polarization data can significantly improve the constraints,
depending on the particular model of primordial physics, and the bounds will
tighten significantly with the inclusion of smaller-scale information.Comment: 15 pages, 9 figures. Submitted to Phys. Rev.
Subnanomolar antisense activity of phosphonate-peptide nucleic acid (PNA) conjugates delivered by cationic lipids to HeLa cells
In the search of facile and efficient methods for cellular delivery of peptide nucleic acids (PNA), we have synthesized PNAs conjugated to oligophosphonates via phosphonate glutamine and bis-phosphonate lysine amino acid derivatives thereby introducing up to twelve phosphonate moieties into a PNA oligomer. This modification of the PNA does not interfere with the nucleic acid target binding affinity based on thermal stability of the PNA/RNA duplexes. When delivered to cultured HeLa pLuc705 cells by Lipofectamine, the PNAs showed dose-dependent nuclear antisense activity in the nanomolar range as inferred from induced luciferase activity as a consequence of pre-mRNA splicing correction by the antisense-PNA. Antisense activity depended on the number of phosphonate moieties and the most potent hexa-bis-phosphonate-PNA showed at least 20-fold higher activity than that of an optimized PNA/DNA hetero-duplex. These results indicate that conjugation of phosphonate moieties to the PNA can dramatically improve cellular delivery mediated by cationic lipids without affecting on the binding affinity and sequence discrimination ability, exhibiting EC50 values down to one nanomolar. Thus the intracellular efficacy of PNA oligomers rival that of siRNA and the results therefore emphasize that provided sufficient in vivo bioavailability of PNA can be achieved these molecules may be developed into potent gene therapeutic drugs
Effective photo-enhancement of cellular activity of fluorophore-octaarginine antisense PNA conjugates correlates with singlet oxygen formation, endosomal escape and chromophore lipophilicity
Abstract Photochemical internalization (PCI) is a cellular drug delivery method based on the generation of light-induced reactive oxygen species (ROS) causing damage to the endosomal membrane and thereby resulting in drug release to the cytoplasm. In our study a series of antisense fluorophore octaarginine peptide nucleic acid (PNA) conjugates were investigated in terms of PCI assisted cellular activity. It is found that tetramethylrhodamine and Alexa Fluor 555 conjugated octaarginine PNA upon irradiation exhibit more than ten-fold increase in antisense activity in the HeLa pLuc705 luciferase splice correction assay. An analogous fluorescein conjugate did not show any significant enhancement due to photobleaching, and neither did an Alexa Fluor 488 conjugate. Using fluorescence microscopy a correlation between endosomal escape and antisense activity was demonstrated, and in parallel a correlation to localized formation of ROS assigned primarily to singlet oxygen was also observed. The results show that tetramethylrhodamine (and to lesser extent Alexa Fluor 555) conjugated octaarginine PNAs are as effectively delivered to the cytosol compartment by PCI as by chloroquine assisted delivery and also indicate that efficient photodynamic endosomal escape is strongly dependent on the quantum yield for photochemical singlet oxygen formation, photostability as well as the lipophilicity of the chromophore
Local Judicial Practices in a Quilombola Territory in Marajó, Pará, Brazil
This article analyzes the socio-judicial organization of a Quilombola community in the state of Pará, Brazil. Using a pluralistic judicial systems approach, we seek to understand how Quilombolas define who has local land rights and to what capacity they can use the territory. The analysis was based on ethnographic field research in the community of Bairro Alto, on Marajó island, in Pará state, Brazil. Methods included: participant observation, interviews and questionnaires. The results showed that order in the territory is maintained through local judicial practices constructed during land occupation processes, and later reorganized on the basis of social relationships involving large-scale farmers, ranchers, neighboring Quilombola communities, and the State. Judicial tenets, intrinsic to the community, guide residents’ current land struggles where they are fighting to restore lands expropriated by ranchers that pertain to their original territory. Local legal practices converge with principles of article 68 of the Federal Constitution, making possible the correction of historical injustices related to land struggles in Quilombola communities.
Cell number and transfection volume dependent peptide nucleic acid antisense activity by cationic delivery methods
Efficient intracellular delivery is essential for high activity of nucleic acids based therapeutics, including antisense agents. Several strategies have been developed and practically all rely on auxiliary transfection reagents such as cationic lipids, cationic polymers and cell penetrating peptides as complexing agents and carriers of the nucleic acids. However, uptake mechanisms remain rather poorly understood, and protocols always require optimization of transfection parameters. Considering that cationic transfection complexes bind to and thus may up-concentrate on the cell surface, we have now quantitatively compared the cellular activity (in the pLuc705 HeLa cell splice correction system) of PNA antisense oligomers using lipoplex delivery of cholesterol- and bisphosphonate-PNA conjugates, polyplex delivery via a PNA-polyethyleneimine conjugate and CPP delivery via a PNA-octaarginine conjugate upon varying the cell culture transfection volume (and cell density) at fixed PNA concentration. The results show that for all delivery modalities the cellular antisense activity increases (less than proportionally) with increasing volume (in some cases accompanied with increased toxicity), and that this effect is more pronounced at higher cell densities. These results emphasize that transfection efficacy using cationic carriers is critically dependent on parameters such as transfection volume and cell density, and that these must be taken into account when comparing different delivery regimes
Magnetic field effects on two-dimensional Kagome lattices
Magnetic field effects on single-particle energy bands (Hofstadter
butterfly), Hall conductance, flat-band ferromagnetism, and magnetoresistance
of two-dimensional Kagome lattices are studied. The flat-band ferromagnetism is
shown to be broken as the flat-band has finite dispersion in the magnetic
field. A metal-insulator transition induced by the magnetic field (giant
negative magnetoresistance) is predicted. In the half-filled flat band, the
ferromagnetic-paramagnetic transition and the metal-insulator one occur
simultaneously at a magnetic field for strongly interacting electrons. All of
the important magnetic fields effects should be observable in mesoscopic
systems such as quantum dot superlattices.Comment: 10 pages, 4 figures, and 1 tabl
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