75 research outputs found
Low-energy features of SU(2) Yang-Mills theory with light gluinos
We report on the latest results of the low-lying spectrum of bound states in
SU(2) Yang-Mills theory with light gluinos. The behavior of the disconnected
contributions in the critical region is analyzed. A first investigation of a
three-gluino state is also discussed.Comment: Talk presented at LATTICE99(Higgs, Yukawa, SUSY), Pisa (Italy),3
pages; to be published in Nucl. Phys. B (Proc. Suppl.
SUSY Ward identities in N=1 SYM theory on the lattice
The SUSY Ward identities (WIs) for the N=1 SU(2) SUSY Yang Mills theory
discretized on the lattice with Wilson fermions (gluinos) are considered. The
study is performed in the framework of a Monte Carlo simulation of the model
with light dynamical gluinos. The renormalization and mixing constants of the
lattice SUSY current and and the additively renormalized gluino
mass are unknown parameters of the SUSY WIs. Using suitable on-shell
combinations of the WIs, the ratios and are determined
non-perturbatively at one value of the coupling constant and two values
of the hopping parameter .Comment: Lattice 2000 (Supersymmetry), 4 pages, 2 figure
Lattice supersymmetric Ward identities
SUSY Ward identities for the N=1 SU(2) SUSY Yang-Mills theory are studied on
the lattice in a non-perturbative numerical approach. As a result a
determination of the subtracted gluino mass is obtained.Comment: 3 pages, 2 figures, Lattice2001(higgssusy
SUSY Ward identities in 1-loop perturbation theory
We present preliminary results of a study of the supersymmetric (SUSY) Ward
identities (WIs) for the N=1 SU(2) SUSY Yang-Mills theory in the context of
one-loop lattice perturbation theory. The supersymmetry on the lattice is
explicitly broken by the gluino mass and the lattice artifacts. However, the
renormalization of the supercurrent can be carried out in a scheme that
restores the nominal continuum WIs. The perturbative calculation of the
renormalization constants and mixing coefficients for the local supercurrent is
presented.Comment: Lattice2001(higgssusy); 3 page
Hydroxyapatite nanocrystals as a smart, pH sensitive, delivery system for kiteplatin
Hydroxyapatite (HA) nanocrystals are important inorganic constituents of biological hard tissues in vertebrates and have been proposed as a bone substitute or a coating material for prostheses in biomedicine. Hydroxyapatite is also amenable for its capacity to bind to a great variety of biomolecules and therapeutic agents. As drug carriers, apatite nanoparticles also have the advantage of pH dependent solubility and low toxicity. Thus HA nanoparticles are negligibly soluble at physiological pH but their dissolution is accelerated at lower pH such as that typically found in the vicinity of tumors. In the present study we have investigated the adsorption on and the release from biomimetic HA nanoparticles of two platinum derivatives of cis-1,4-diaminocyclohexane ([PtX2(cis-1,4-DACH)], X2 = Cl2 (1) and 1,1-cyclobutanedicarboxylate (CBDCA, 2)). The first of the two compounds proved to be active against colon cancer cells also resistant to oxaliplatin. The release has been investigated as a function of pH to mimic the different physiological environments of healthy tissues and tumors, and the in vitro cytotoxicity of the releasates from the HA matrices has been assessed against various human cancer cell lines. The results fully confirmed the potential of 1-loaded HA nanoparticles as bone-specific drug delivery devices
Lattice energy-momentum tensor with Symanzik improved actions
We define the energy-momentum tensor on lattice for the and
for the nonlinear -model Symanzik tree-improved actions, using Ward
identities or an explicit matching procedure. The resulting operators give the
correct one loop scale anomaly, and in the case of the sigma model they can
have applications in Monte Carlo simulations.Comment: Self extracting archive fil
Effective Lagrangian for Quantum Black Holes
We discuss the most general effective Lagrangian obtained from the assumption
that the degrees of freedom to be quantized, in a black hole, are on the
horizon. The effective Lagrangian depends only on the induced metric and the
extrinsic curvature of the (fluctuating) horizon, and the possible operators
can be arranged in an expansion in powers of \mpl/M, where \mpl is the
Planck mass and the black hole mass. We perform a semiclassical expansion
of the action with a formalism which preserves general covariance explicitly.
Quantum fluctuations over the classical solutions are described by a single
scalar field living in the 2+1 dimensional world-volume swept by the horizon,
with a given coupling to the background geometry. We discuss the resulting
field theory and we compute the black hole entropy with our formalism.Comment: 24 pages, Latex, Nucl. Phys. B, to appea
ATP Sensitive Potassium Channels in the Skeletal Muscle Function: Involvement of the KCNJ11(Kir6.2) Gene in the Determination of Mechanical Warner Bratzer Shear Force
The ATP-sensitive K-channels (KATP) are distributed in the tissues coupling metabolism with K ions efflux. KATP subunits are encoded by KCNJ8 (Kir6.1), KCNJ11 (Kir6.2), ABCC8 (SUR1), and ABCC9 (SUR2) genes, alternative RNA splicing give rise to SUR variants that confer distinct physiological properties on the channel. An high expression/activity of the sarco-KATP channel is observed in various rat fast-twitch muscles, characterized by elevated muscle strength, while a low expression/activity is observed in the slow twitch muscles characterized by reduced strength and frailty. Down-regulation of the KATP subunits of fast-twitch fibers is found in conditions characterized by weakness and frailty. KCNJ11 gene knockout mice have reduced glycogen, lean phenotype, lower body fat, and weakness. KATP channel is also a sensor of muscle atrophy. The KCNJ11 gene is located on BTA15, close to a QTL for meat tenderness, it has also a role in glycogen storage, a key mechanism of the postmortem transformation of muscle into meat. The role of KCNJ11 gene in muscle function may underlie an effect of KCNJ11 genotypes on meat tenderness, as recently reported. The fiber phenotype and genotype are important in livestock production science. Quantitative traits including meat production and quality are influenced both by environment and genes. Molecular markers can play an important role in the genetic improvement of animals through breeding strategies. Many factors influence the muscle Warner-Bratzler shear force including breed, age, feeding, the biochemical, and functional parameters. The role of KCNJ11gene and related genes on muscle tenderness will be discussed in the present review
Transcript Regulation of the Recoded Archaeal α-L-Fucosidase In Vivo
Genetic decoding is flexible, due to programmed deviation of the ribosomes from standard translational rules, globally termed ârecodingâ. In Archaea, recoding has been unequivocally determined only for termination codon readthrough events that regulate the incorporation of the unusual amino acids selenocysteine and pyrrolysine, and for â1 programmed frameshifting that allow the expression of a fully functional α-l-fucosidase in the crenarchaeon Saccharolobus solfataricus, in which several functional interrupted genes have been identified. Increasing evidence suggests that the flexibility of the genetic code decoding could provide an evolutionary advantage in extreme conditions, therefore, the identification and study of interrupted genes in extremophilic Archaea could be important from an astrobiological point of view, providing new information on the origin and evolution of the genetic code and on the limits of life on Earth. In order to shed some light on the mechanism of programmed â1 frameshifting in Archaea, here we report, for the first time, on the analysis of the transcription of this recoded archaeal α-l-fucosidase and of its full-length mutant in different growth conditions in vivo. We found that only the wild type mRNA significantly increased in S. solfataricus after cold shock and in cells grown in minimal medium containing hydrolyzed xyloglucan as carbon source. Our results indicated that the increased level of fucA mRNA cannot be explained by transcript up-regulation alone. A different mechanism related to translation efficiency is discusse
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