Protein homeostasis (proteostasis) is a result of a dynamic equilibrium between protein synthesis and degradation. It is important for healthy cell/organ functioning and is often associated with ...diseases such as neurodegenerative diseases and non-Alcoholic Fatty Liver disease. Heavy water metabolic labeling, combined with liquid-chromatography and mass spectrometry (LC-MS), is a powerful approach to study proteostasis in vivo in high throughput. Traditionally, intact peptide signals are used to estimate stable isotope incorporation in time-course experiments. The time-course of label incorporation is used to extract protein decay rate constant (DRC). Intact peptide signals, computed from integration in chromatographic time and mass-to-charge ratio (m/z) domains, usually, provide an accurate estimate of label incorporation. However, sample complexity (co-elution), limited dynamic range, and low signal-to-noise ratio (S/N) may adversely interfere with the peptide signals. These artifacts complicate the DRC estimations by distorting peak shape in chromatographic time and m/z domains. Fragment ions, on the other hand, are less prone to these artifacts and are potentially well suited in aiding DRC estimations. Here, we show that the label incorporation encoded into the isotope distributions of fragment ions reflect the isotope enrichment during the metabolic labeling with heavy water. We explore the label incorporation statistics for devising practical approaches for DRC estimations.
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•In vivo Proteome dynamics estimation using fragment ions.•Natural and fragment ion isotope distributions.•Spectral accuracy correction.•Time-course modeling.•Heavy Water Stable Isotope Metabolic Labeling.
Within the context of a \(5D\) space-time, we construct a unified theory of gravity and electromagnetism from which the Einstein field equations and Maxwell equations emerge, with homogenous Maxwell ...equations appearing naturally. We also introduce a well-defined five dimensional energy-momentum tensor consistent with our unification scheme. A correction term appears in Maxwell equations which can be used to explain the recently discovered galactic magnetic fields.
We present a five dimensional unified theory of gravity and electromagnetism which leads to modified Maxwell equations, suggesting a new origin for galactic magnetic fields. It is shown that a region ...with nonzero scalar curvature would amplify the magnetic fields under certain conditions.
Europhys.Lett.88:29001,2009 We consider a brane world scenario in which the bulk action is assumed to
have the form of a generic function of the Ricci scalar $f(\mathcal{R})$ and
derive the resulting ...Einstein field equations on the brane. In a constant
curvature bulk a conserved geometric quantity appears in the field equations
which can be associated with matter. We present cosmological and spherically
symmetric solutions by assuming specific forms for $f(\mathcal{R})$ and show
that the former can explain an accelerated expanding universe while the latter
may account for galaxy rotation curves.
We consider a brane world scenario in which the bulk action is assumed to have the form of a generic function of the Ricci scalar \(f(\mathcal{R})\) and derive the resulting Einstein field equations ...on the brane. In a constant curvature bulk a conserved geometric quantity appears in the field equations which can be associated with matter. We present cosmological and spherically symmetric solutions by assuming specific forms for \(f(\mathcal{R})\) and show that the former can explain an accelerated expanding universe while the latter may account for galaxy rotation curves.
The stability of isothermal dark matter halos has been widely studied before. In this paper, we investigate the stability of non-isothermal fermionic dark matter halos. We show that in the presence ...of temperature gradient, the force due to the pressure has both inward and outward components. In some regions of halos, the inward force that provides stability is due to the pressure rather than gravity. Moreover, it is shown that higher temperature gradients lead to halos with lower mass and size. We prove that if the temperature is left as a free positive profile, one can place no phase-space lower bound on the mass of dark matter. For halos that are in the low degeneracy classic domain, we derive an analytic expression of their temperature in terms of their mass density and place an upper bound on the mass of dark matter by requiring that temperature is not negative. We then use the Burkert mass profile for the Milky Way to show that if the central temperature of the halo is a few Kelvins, the mass of dark matter cannot exceed a few keV.
Abstract We replace general relativity (GR) and the cosmological constant ($$\Lambda $$ Λ ) in the standard cosmology (SM–GR–$$\Lambda $$ Λ –CDM) with a Lorentz gauge theory of gravity (LGT) and show ...that the standard model (SM) neutrinos can be the cold dark matter (CDM) because (1.) the expansion of the universe at early times is not as sensitive to the amount of radiation as in the SM–GR–$$\Lambda $$ Λ –CDM and (2.) in LGT there exists a spin-spin long-range force that is very stronger than the Newtonian gravity and interacts with any fermion including neutrinos. Assuming that neutrinos as heavy as 1 eV are the cold dark matter, the lower bound on the dimensionless coupling constant of LGT is derived to be $$10^{-7}$$ 10-7 which is small enough to be consistent with the upper bound that can be placed by the electroweak precision tests. We also show that the vacuum energy does not gravitate in LGT and a decelerating universe shifts spontaneously to an accelerating one right at the moment that we expect. Therefore, current observations can be explained in our cosmological model (SM–LGT) with lesser assumptions than in the SM–GR–$$\Lambda $$ Λ –CDM.
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