2,178 research outputs found
Functional proteomics.
Background: With the increase in the number of genome sequencing projects, there is a concomitant exponential growth in the number of protein sequences whose function is still unknown. Functional proteomics constitutes an emerging research area in the proteomic field whose approaches are addressed towards two major targets: the elucidation of the biological function of unknown proteins and the definition of cellular mechanisms at the molecular level. Methods: The identification of interacting proteins in stable complexes in vivo is essentially achieved by affinity-based procedures. The basic idea is to express the protein of interest with a suitable tag to be used as a bait to fish its specific partners out from a cellular extract. Individual components within the multi-protein complex can then be identified by mass spectrometric methodologies. Results and conclusions: The association of an unknown protein with partners belonging to a specific protein complex involved in a particular mechanism is strongly suggestive of the biological function of the protein. Moreover, the identification of protein partners interacting with a given protein will lead to the description of cellular mechanisms at the molecular level. The next goal will be to generate animal models bearing a tagged form of the bait protein
Resonant modes in strain-induced graphene superlattices
We study tunneling across a strain-induced superlattice in graphene. In
studying the effect of applied strain on the low-lying Dirac-like spectrum,
both a shift of the Dirac points in reciprocal space, and a deformation of the
Dirac cones is explicitly considered. The latter corresponds to an anisotropic,
possibly non-uniform, Fermi velocity. Along with the modes with unit
transmission usually found across a single barrier, we analytically find
additional resonant modes when considering a periodic structure of several
strain-induced barriers. We also study the band-like spectrum of bound states,
as a function of conserved energy and transverse momentum. Such a
strain-induced superlattice may thus effectively work as a mode filter for
transport in graphene
Exploring the mechanism of formation of native-like and precursor amyloid oligomers for the native acylphosphatase from Sulfolobus solfataricus
Over 40 human diseases are associated with the formation of well-defined proteinaceous fibrillar aggregates. Since the oligomers precursors to the fibrils are increasingly recognized to be the causative agents of such diseases, it is important to elucidate the mechanism of formation of these early species. The acylphosphatase from Sulfolobus solfataricus is an ideal system as it was found to form, under conditions in which it is initially native, two types of prefibrillar aggregates: (1) initial enzymatically active aggregates and (2) oligomers with characteristics reminiscent of amyloid protofibrils, with the latter originating from the structural reorganization of the initial assemblies. By studying a number of protein variants with a variety of biophysical techniques, we have identified the regions of the sequence and the driving forces that promote the first aggregation phase and show that the second phase consists in a cooperative conversion involving the entire globular fol
Dynamical polarization of graphene under strain
We study the dependence of the plasmon dispersion relation of graphene on
applied uniaxial strain. Besides electron correlation at the RPA level, we also
include local field effects specific for the honeycomb lattice. As a
consequence of the two-band character of the electronic band structure, we find
two distinct plasmon branches. We recover the square-root behavior of the
low-energy branch, and find a nonmonotonic dependence of the strain-induced
modification of its stiffness, as a function of the wavevector orientation with
respect to applied strain.Comment: Phys. Rev. B, accepte
Statistical correlations of an anyon liquid at low temperatures
Using a proposed generalization of the pair distribution function for a gas
of non-interacting particles obeying fractional exclusion statistics in
arbitrary dimensionality, we derive the statistical correlations in the
asymptotic limit of vanishing or low temperature. While Friedel-like
oscillations are present in nearly all non-bosonic cases at T=0, they are
characterized by exponential damping at low temperature. We discuss the
dependence of these features on dimensionality and on the value of the
statistical parameter alpha.Comment: to appear in Phys. Chem. Liquid
Abdominal intercostal hernia: a rare complication after blunt trauma.
Abdominal intercostal hernia (AIH) is uncommonly reported in the literature with only 20 cases reported to date.1–3 We report a case of a delayed incarcerated AIH secondary to blunt trauma from a motor vehicle accident in which the colon and diaphragm herniated through an associated chest defect that was repaired successfully through a transabdominal approach using primary repair of the defect in combination with onlay porcine patch reinforcement
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